英文论文diesel engine development and durability

生物柴油循环英语作文Possible essay:Bio-diesel Cycling: Enhancing Sustainability and Energy SecurityBio-diesel, or fatty acid methyl ester (FAME), is a renewable and clean-burning alternative to petroleum diesel that can be made from various sources of vegetable oil, animal fat, and used cooking oil. Bio-diesel has several advantages over traditional diesel, such as lower greenhouse gas emissions, better lubricity, and higher cetane number. Moreover, bio-diesel can be produced locally, thereby reducing dependence on imported fossil fuels and enhancing energy security. However, the production and useof bio-diesel also entail environmental, economic, andsocial impacts that need to be carefully assessed and managed to ensure sustainability.Q: What is bio-diesel, and what are some of its benefits?A: Bio-diesel is a type of renewable diesel fuel made from natural oils or fats. It is produced by chemically reacting the oil or fat with an alcohol (usually methanol)and a catalyst (usually sodium hydroxide) to form theesters and glycerol. Bio-diesel can be blended with petroleum diesel or used pure in engines that arespecifically designed or modified for bio-diesel. Some of the benefits of bio-diesel include:- Lower emissions of particulate matter, carbon monoxide, hydrocarbons, and sulfur dioxide compared to petroleum diesel.- Reduced greenhouse gas emissions, especially if the feedstock is produced sustainably and the bio-diesel isused efficiently.- Higher lubricity and cetane number, which can improve engine performance, reduce wear and tear, and extend thelife of the engine.- Better biodegradability and low toxicity, which can reduce the environmental impact of spills and leaks.- Domestic production potential, which can enhanceenergy security, create jobs, and support local agriculture and waste reduction.Q: How is bio-diesel produced, and what are some of the challenges and opportunities?A: Bio-diesel can be made from various sources of oils or fats, such as soybean oil, canola oil, palm oil, waste cooking oil, animal fat, and algae. The choice of feedstock depends on factors such as availability, cost, quality, and sustainability. Most bio-diesel is produced by the transesterification process, which involves several steps: - Pretreatment: The oil or fat is filtered, degummed, and dried to remove impurities and water.- Reaction: The oil or fat is mixed with methanol and a catalyst to form the esters and glycerol.- Separation: The esters and glycerol are separated by gravity or centrifugation, and the glycerol is further purified or sold as a by-product.- Washing: The esters are washed with water or an acidic solution to remove residual methanol and catalyst.- Drying: The esters are dried and stored in tanks or blended with petroleum diesel.The production of bio-diesel faces several challenges and opportunities, such as:- Feedstock availability and quality: Some feedstocks are more abundant, affordable, and sustainable than others, but they may also compete with food, land, water, and biodiversity. Moreover, the quality of the feedstockaffects the yield, purity, and stability of the bio-diesel.- Production efficiency and cost: Thetransesterification process requires energy, water, chemicals, and equipment, which can vary in efficiency, cost, and environmental impact. The choice of process also affects the yield, quality, and safety of the bio-diesel.- Market demand and regulation: The demand for bio-diesel depends on factors such as the price, performance, and availability of petroleum diesel, the incentives and mandates for renewable energy, and the consumer awareness and preference for sustainable fuels. The regulation ofbio-diesel also varies among countries and regions, and may affect the production, trade, and environmental impact of the fuel.- Innovation and collaboration: The development of advanced bio-diesel technologies, such as enzymatic or microbial conversion, can enhance the efficiency, sustainability, and diversity of feedstocks and processes. The collaboration among stakeholders, such as farmers, processors, distributors, and consumers, can also promote the social, economic, and environmental benefits of bio-diesel.Q: How does bio-diesel cycling work, and what are some of the benefits and challenges?A: Bio-diesel cycling, or closed-loop bio-diesel, is a system that uses the waste products of bio-diesel production as feedstock for new bio-diesel production. The system involves several steps:- Collection: The waste glycerol from the transesterification process is collected and purified to remove impurities and methanol.- Conversion: The purified glycerol is converted into glycerol carbonate, which is a valuable feedstock for new bio-diesel production.- Incorporation: The glycerol carbonate is mixed withthe oil or fat and methanol to form new esters and glycerol.- Separation: The new esters and glycerol are separated and purified as before, and the glycerol is recycled as feedstock for glycerol carbonate production.Bio-diesel cycling has several benefits, such as:- Reduced waste and pollution: The recycling of glycerol reduces the amount of waste and pollution generated by bio-diesel production, and enhances the sustainability and circularity of the process.- Increased efficiency and profitability: The conversion of glycerol into glycerol carbonate adds value to the waste product and provides a cheaper and more stable feedstockfor bio-diesel production.- Enhanced energy security and local economy: Theclosed-loop system reduces the dependence on imported or volatile feedstocks, and supports the local production and use of bio-diesel.- Improved environmental and social performance: The recycling of glycerol reduces the environmental impact ofglycerol disposal, and can create jobs and income for local communities.However, bio-diesel cycling also faces some challenges, such as:- Technical complexity and cost: The conversion of glycerol into glycerol carbonate requires specialized equipment and expertise, and may increase the cost and risk of bio-diesel production.- Quality control and standardization: The glycerol carbonate must meet certain specifications and standards to ensure the quality and safety of the bio-diesel, and the lack of uniformity or regulation may hinder the adoption of bio-diesel cycling.- Feedstock availability and sustainability: The availability and sustainability of the feedstock for glycerol carbonate production depend on factors such as the quality, quantity, and competition of the waste glycerol, and the environmental and social impacts of the feedstock production.- Public awareness and acceptance: The benefits and challenges of bio-diesel cycling need to be communicated and evaluated to ensure public awareness and acceptance, and to promote the adoption and improvement of the technology.In conclusion, bio-diesel cycling is a promising and innovative approach to enhancing the sustainability and energy security of bio-diesel production and use. The system can reduce waste and pollution, increase efficiency and profitability, enhance energy security and local economy, and improve environmental and social performance. However, bio-diesel cycling also requires careful evaluation and management of its technical, economic, environmental, and social aspects to ensure its viability and effectiveness. Bio-diesel cycling is a part of the larger effort to transition to a more sustainable and resilient energy system that meets the needs of people, planet, and prosperity.。

Domestic and foreign automobile engine technology statusand development trendFrom the invention of the internal combustion engine development to one hundred years later, the relevant technical innovation and mature. However, the internal combustion engine as vehicle power still faces many problems, mainly thermal efficiency is not high enough (especially gasoline), relies diminishing oil resources, atmospheric pollution emissions, and difficulty concentrating governance. Therefore, the advanced engine technology in the automotive energy-saving, environmental protection, technological development plays a key decisive role.First, the diesel engine's status and development trend1.1 diesel engine performance characteristics1) there is a high energy density (large low-speed supercharged diesel engine thermal efficiency over 50%), low fuel consumption, which saves energy and improve economic efficiency are important.2) good fuel economy;3) less greenhouse gas emissions, the CO2 emissions than its gasoline low around 30-35%, but the exhaust gases contain harmful ingredients (NO, particulate matter, etc.) are more noisy, environmental aspects in the environment has attracted attention.4) a great range of power and speed (power 1-65580KW, speed 54-5000r/min), so wide application area.5) structure is more complex, parts materials and processes are higher, higher manufacturing costs, higher quality compared with gasoline. There are threemajor advantages:a. economy. Firstly, the energy content of diesel fuel per unit than gasoline; secondly, a compression ignition engine characteristics, so that the thermal efficiency higher than gasoline. Average fuel consumption of diesel gasoline lower than 30% to 40%.b. environmental protection. In general, the main vehicle emissions of carbon monoxide, hydrocarbons, carbon dioxide, particulate matter and nitrogen oxides. In contrast, the engine of the carbon monoxide, hydrocarbons and carbon dioxide emissions is very low, but the particulate matter and nitrogen oxide emissions than gasoline control more difficult to handle. This is due to the characteristics of the engine itself, through modern technology to settle.c. diesel engine low speed high torque characteristics of the car provides better performance. Through the use of advanced technology and electronically controlled fuel injection technology, modern diesel engines in the power, speed, comfort indicators have been tantamount to gasoline.1.2 Status of foreign diesel technologyWestern European countries currently only trucks and buses use diesel engines, but the proportion of cars using diesel is quite large. Recently, the U.S. Department of Energy and the federal government to the three major U.S. auto companies on behalf of the American Automobile Research Institute Council is developing a new generation diesel economy cars will be the same as the power configuration. After years of research, a lot of new technology, the biggest problem diesel smoke and noise major breakthrough, reaching the level of gasoline. Here are some of the current foreign diesel applications of new technologies:1) Common rail with four-valve technologyCommon rail diesel engine is currently commonly used foreign new technology, four-valve technology and turbo intercooler technology combine to make the engine performance and emission limits achieved good results, to meet Euro 3 emission limits and regulations.The first high-pressure diesel fuel at high pressure common rail system (spray oil) state sets in what is called common rail storage container, and the electromagnetic three-way valve and the injection pressure in the common rail diesel fuel leads to the same injector jet tasks to complete. Installed in the high pressure in the use of high-speed, powerful electromagnetic relief valve to control the start of injection and direct fuel injection, gasoline engine with electronically controlled fuel injection system principle difference is that you can also change the time or change the solenoid valve lift pressure The hydraulic oil to achieve the injection rate and injection pressure control. It also has the energysub-cylinder control and fast response and so on.Four-valve structure (binary gas two exhaust) not only can improve the filling efficiency, but also because the nozzle can be centrally disposed, uniform distribution of the porous oil-beam, for the good mixing of fuel and air to create conditions; Meanwhile, in four-valve Head Admiral inlet design into two separate structures having the same shape, in order to achieve variable swirl. Coordination of these factors, can greatly improve the quality of the mixture formation (quality), reduce soot, HC and NOX emissions and improve thermal efficiency.2) high-pressure injection and electronically controlled injection technology High-pressure injection and electronically controlled injection technology is currently abroad, an important measure to reduce diesel emissions, onehigh-pressure injection and electronically controlled injection technology, effective use, can make full fuel atomization, each cylinder for optimal fuel andair mixing, thereby reducing emissions, improve machine (car) performance.3) turbocharged and intercooled technologyTurbocharged diesel engine to increase the amount of air to improve combustion of the excess air factor is to reduce the high load exhaust smoke, PM emissions and fuel consumption of effective measures. Effective air - air cooling system, can charge air temperature dropped to below 50 ℃, the temperature dropped to help the working cycle of low NOX and PM emissions decline, it is currently heavy-duty diesel engine is turbocharged and have generally cold type, not only helps to lower emissions and good fuel economy. In addition, the turbine exhaust bypass valve before the application can not only reduce PM and CO emissions, but also can improve the transient turbocharged diesel engine performance and low-speed torque.4) an exhaust gas recirculation (EGR) technologyEGR is commonly used in internal combustion engines developed advanced technology, its working principle is to introduce a small amount of exhaust gas within the cylinder, which can no longer burning CO2 and water vapor exhaust heat capacity is large, the combustion process can increase the ignition delay period, burning rate slows down, the maximum cylinder combustion temperature decreases, destruction of NOX formation conditions. EGR technology can significantly reduce motor vehicle emissions of NOX, but the heavy-duty diesel engine, the current preference for the use of cold EGR technology, because it not only can significantly reduce NOX, but also to maintain low levels of other pollutants.5) post-processing techniquesPost-processing of the target engine is to further improve the PM and NOX emissions. Currently the main use to install oxidation catalytic converter and theresearch and development of NOX catalytic converter and has a good ability to regenerate the particulate filter.6) reduce oil consumptionParticulate emissions from diesel engines, a considerable part of the heavy distillate oil from burning. To meet the increasingly stringent engine (vehicle) standards emission limits, to the combustion of oil drops from the minimum, i.e. to ensure the normal operation of the engine under the premise of minimizing the consumption of oil. In order to reduce diesel oil consumption, optimizing the design and manufacture of piston rings and cylinder configuration between science is very important.1.3 Status of domestic diesel technologySince 2003, the domestic diesel engine industry experienced a structural adjustment: Weifang Diesel Engine Factory in 2002 on the basis of continued rapid growth momentum, the power level has also been significantly improved; Shanghai Diesel Engine Factory in the field of commercial vehicle diesel Blair, mainly due to BAIC Foton Auman heavy truck market share rapidly increasing; Guangxi Yuchai Machinery Co., Ltd. As an industry leader for a new round of product structure optimization, the smooth realization of products from Europe to the Euro ⅡⅠ transition, improved product lines ( From 4 to 6 cylinder engine cylinder machine) platform to further expand the power range, the maximum power level diesel engine can reach 257 kW (350 ps). The overall level has been significantly improved. Both from an economic or from an environmental perspective, the domestic diesel engine technology is already close to the world average. Production engine has been fully able to meet the low-end domestic heavy truck and passenger demand on the engine, without outsourcing.1.4 diesel engine trendsHeavy, huge diesel engine noise and vibration, used trucks, cars and machinery thoroughbred sport utility vehicle. But with the advances in diesel engine technology, and now many new diesel performance indicators have been able and comparable gasoline engine (and even beyond), and its unmatched fuel economy will have far better than gasoline. Therefore, more and more new cars diesel engines began to adopt. TDI is the English "Turbo Direct Injection" abbreviation Chinese means "electronically controlled common rail direct injection turbo diesel engine." TDI through the use of electronically controlled common rail direct injection and turbocharger technology, to solve the many problems of older diesel engines.Global automotive "diesel" trend has been formed. In the United States, Japan and Europe, 100% heavy-duty diesel-powered cars. In Europe, 90% and 33% of commercial vehicle diesel sedans. In the United States, 90% of commercial vehicles for the diesel vehicles. In Japan, 38% of commercial vehicles to diesel vehicles, 9.2% of the cars as diesel cars. Experts predict that in the next 20 years or even longer period of time will become the world'sdiesel-powered vehicles mainstream. Governments of developed countries on the world automobile engine development has also been given a high priority, from tax, fuel supply and has taken measures to promote the popularization and development of diesel engines.Current and future diesel engine technology for a period trends highlighted in the following aspects:1) to further optimize the combustion system, with particular emphasis injection systems development and selectionPerkins's Ouadram combustion chamber, the combustion chamber Hino's HMMS, Komatsu Isuzu MTEC combustion chamber and the combustion chamberquadrangle, etc., are in the experimental stage of development, its basic features are a central vortex and swirl the air around the micro- fuel quickly and thoroughly mixed, and with an appropriate fuel injection system. At present, the injection system has entered a period of rapid development, research and development is being injected to complete a lms and limited time to properly control method of the injection quantity. Injection pressure has been increased to 160-180MPa, the laboratory has to 200 MPa. Such as common rail injection system and segmented pre-injection system, according to the engine load and speed automatically controlled injection reasonable rules and injection pressure. 2) turbocharger and variable valve timing valve supercharged and turbocharged diesel engines today have become standard features of the cold, with the engine's lightweight and small, in order to reduce vehicle fuel consumption and improve vehicle loading efficiency, we must continue to improve the supercharger ratio and turbocharger efficiency. Further increase in the load zone of a large excess air coefficient a can be reduced particulate emissions, and through the lean, and reduce heat loss and improve cycle efficiency, thereby reducing fuel consumption while, with a high supercharging and high technology, a plurality of assembly Compound turbocharger systems have become possible. Further, the fixed turbine turbocharger geometry will also be available for multipurpose electric replaced variable geometry. At present, the diesel engine in a small bore valve and an injector 4 vertical center technology has been widely applied, in order to reduce ventilation losses, the formation of the mixed gas further optimization is being studied valve with variable valve timing of the engine the entire speed range of the valve lift and timing to get the best optimization. 3) fully electronic optimization control described above, the current fuel injection timing, injection quantity, inertia supercharging, turbocharger, intake swirl, and an exhaust gasrecirculation (EGR), etc. can be optimized to achieve a variable electronic control, thus to reduce emissions and reduce fuel consumption, increase power output and startup performance plays a significant role; however, most of these controls in the content, such as EGR, automatic diagnosis, there are many techniques not perfect, pending further research and development in the future also will continue to develop other aspects of the electronic variable control mechanism, especially with the harmonization of the vehicle relative to the integration of the entire electronic control system. 4) whether the diesel exhaust after-treatment technologies such as the use of a catalyst gasoline significantly reduce emissions, especially NOx, which is the developer of diesel engines has been pursuing. United States and Europe are conducted in this study, the relevant Japanese universities, research institutes and manufacturers are magnesium and alumina, zeolite catalyst with a reducing agent for NOx reduction test, Ford and other companies are also on the catalytic reduction system (SCR) and DeNOx, catalytic converters two kinds of NOx reduction systems research. SCR technology is the use of nitrogen oxides are selectively present in the exhaust gas injected into the reactants or the reaction, the use of a catalytic converter reduces NOx emissions, exhaust oxygen gas. Reduction agent may be an HC in the exhaust gas of the diesel engine or by an additional tank compounds directly into the exhaust stream of substances, such as ammonia. Compared with SCR technology, DeNOx catalytic technology system is simple, no harmful product, currently considered the most development potential. DeNOx catalytic technology mainly to the NOx catalytic thermal fission of N2 and O2, the current problem is the catalytic converter in the exhaust gas residence time, catalytic converter efficiency is not high, so bring transformation and reduction efficiency is very restricted. To reduce particulate emissions and the development of various "known dieselparticulate traps or filters (DEF)", although many products available in Europe on diesel cars loading use, but the durability is poor and the DEF filter regeneration problems not completely resolved, therefore, the technology is also being further improved and developed.5) improving fuel fuel performance improvements, played a significant role in reducing emissions, following the United States and Europe, Japan, the beginning in 1997 to the sulfur content of gas oil to 0.05% or less, in order to significantly reduce emissions of particulate sulphate, while reducing the internal EGR caused by corrosion of the engine wear and catalyst poisoning; further reduced sulfur content, cetane number, can further reduce NOx. Reducing aromatics, especially the reduction of 3 or more rings of the aromatic component, to reduce emissions of sulfur particles, 90% distillation temperature, improved ignition performance; through the use of oxy-fuel or additives to reduce smoke particles. To meet low sulfur and injection pressure increased significantly, to ensure lubricity of fuel injection device, it improve the development of fuel placed great expectations. Second, gasoline machine technology status and development trendCurrently, the most widely used, the largest number of automobile engine is water-cooled, four-stroke reciprocating piston internal combustion engine, in which more than gasoline for cars and light goods vehicles, buses and medium and heavy-duty truck engines, mostly diesel engines. Few cars and light vans diesel engine is also useful. There is also a high profile, but very few applications of the engine, which is triangular rotary piston engine, the rotor engine. Such as Mazda's RX-7 sports car is to install the rotary engine.2.1 Gasoline foreign technology statusTo accommodate for fuel-efficient cars, environmental protection, security needs, Gasoline mainly toward more fuel-efficient and more environmentallyfriendly direction, it has been performed in Europe Europe Ⅳ standard. The following is abroad in the main aspects of advanced technology gasoline.1) multi-valve technology: four valves per cylinder 3-5 (mostly 4-valve), can improve the power, improved combustion quality, such as 5-valve Jetta, Toyota8A4 valve and so on.2) double overhead camshaft (D.HC) can increase speed, improve reliability.3) variable valve timing (VVT): Depending on the speed control valve, you can save fuel, improve emissions, such as the Honda VTEC, Toyota's VVT-i and so on.4) Gasoline Turbocharged: to improve the power per liter in the case of constant displacement, can improve the power, such as the Passat 1.8T sedan.5) variable inlet length (VIM): at different speeds with different inlet lengths to ensure that any conditions have better volumetric efficiency, such as the Audi A6.6) cylinder deactivation technology: in the output power is reduced, so that partof the cylinder to stop working, you can save fuel, such as General Blazers EXT 2005 models have eight cylinders, four cylinders when needed make a stop working.7) aluminum engine: Use aluminum cylinder block, cylinder heads, pistons, etc., can reduce the quality, save fuel, such as Japan, Suzuki 1.3L, 1.4L gasoline engine.8) smart drive valve (SV A): replace the traditional camshaft, each valve lifter hasa separate drive, fuel consumption can be reduced 20% and contaminants, such as: France, Valeo has designed a prototype in 2009 to high-volume production.9) variable compression ratio gasoline engine: the transmission power control function with integrated compression ratio, the compression ratio is variable. 2005 French MCE-5 company has developed a prototype.10) Gasoline Direct Injection (GDI) and lean-burn technology: high-pressure gasoline direct injection into the cylinder, surrounded by a lean mixture, to achieve stratified combustion, can improve fuel economy, saving about 20%, such as Toyota Huang. Crown 3.0L V6 gasoline engine (domestic crown without GDI technology).11) controllable burning rate of the system (CBR): two inlet, one of which is tangential inlet, and the other is neutral. Injector equal to two fuel injected into the inlet. Changing inlet control valve closed position, the air cylinder can be adjusted and mixed gas concentration swirl strength, lean burn;12) engine control ECU has reached 32, matching parameters over 6000.2.2 Domestic gasoline engine technology statusIn technical applications, the majority of models and the introduction of a joint venture production models have adopted a number of advanced foreign technology.1) Tianjin Toyota 8A, 5A, Dongfeng Honda, Beijing Hyundai, Chery SQR372 (0.8L), SQR481Q (1.6L), DPCA Elysee (1.6L), and so the use of multi-valve DOHC technology.2) Dongfeng Honda Engine, Tianjin Toyota Corolla Engine Co., Crown gasoline, Dongfeng Nissan, Beijing Hyundai and other gasoline produced models are introduced variable valve timing technology (VTEC, VVT-i, CVVT, etc.). Especially Chery company, A VL, developed with the help of independent brands 1.6LSQR481H and 2.0L SQR484H VVT petrol engine uses variable valve timing technology, Geely has also developed a technology with variable gasoline brands.3) Gasoline Direct Injection (GDI) engine is not yet mass-produced, but Chery company A VL, developed with the help of independent brands 2.0L SQR484J gasoline use of GDI technology.4) aluminum engine more domestic products, such as Changan Suzuki Swift 1.3L gasoline engine, Dongfeng Honda Engine products, Shanghai V olkswagen POLO engines, Chery Power 1.6L SQR481F (already in operation) and SQR481 H and not commissioned SQR484J, SQR681 V (2.4L), SQR684V (3.0L) all-aluminum engine.5) Domestic Chery company has commissioned its own brand SQR481H (1.6L) has a CBR system prototype lot of other Chery models are also equipped with CBR system.6) domestic production models have been introduced quite a number of models using turbo technology: such PASSAT 1.8T, 1.8T Bora etc.; Brilliance Jinbei company in Germany, developed with the help FEV 1.8T gasoline engine is supercharged machine type (Zhonghua sedans equipped).7) cylinder deactivation technology, intelligent valve timing, variable compression ratio technology is not yet in the domestic production of gasoline used.8) EFI engine management system (EMS) are mainly domestic United Electronics Company Limited, Beijing Wan Yuan Delphi Engine Management Systems, namely China and Germany BOSCH Delphi Corporation and China and the United States joint venture. Meanwhile, there Marelli, Denso and Motorola enterprise production.9) Electronic Fuel Injection system, sensors, electronic control fuel injection pump and other domestic own production; gasoline engine exhaust system, three-way catalytic converter and ceramic core, etc., have domestic production, such as: Dalian Hua Keji to special, Tianjin Qatar grams of high-tech companies such as production of three-way catalytic converter; owned enterprises in Suzhou Japan NGK (Suzhou) Co., Ltd. green ceramic producer Ⅲ, State Ⅳ gasolineengine three-way catalytic converter ceramic core and so on. 2.3 gasoline engine technology trendsAutomotive future trends can be summarized as high power, high torque, low fuel consumption and low emissions.Since gasoline fuel economy than diesel poor, so reducing gasoline consumption has become the automotive industry must address a current problem. With a stoichiometric homogeneous mixture combustion spark ignition engine theory is widely used, its greatest advantage is practical three-way catalytic converter to reduce CO, HC and NOx and other emissions. The downside is that can not get higher fuel economy, in order to improve the engine's thermal efficiency and reduce exhaust emissions, combustion technology is constantly evolving. Experienced by the gasoline engine carburetor completely mechanically controlled fuel injection mainly to the use of electronic control, direct injection, electric auxiliary supercharger and electric valves, variable compression ratio, cylinder deactivation technology changes, the development of the final gasoline programs will be integrated advantages of gasoline and diesel combustion control technology.Representative of the three most gasoline engine technologies are:Gasoline direct injection technology. Development car with gasoline engine also has the advantages of high part-load fuel economy advantage of the engine is the main research goals. Gasoline direct injection gasoline engine to improve fuel economy an important means, in recent years, in order to direct injection gasoline engine (Gasoliine Direct Injection, GDI) as the representative of the new mixture formation model research and application, which greatly improved the gasoline engine fuel economy. Japan as the representative of a non-homogeneous direct injection technology faces combustion stability and post-processing and otherissues, both in Europe as the representative of homogeneous direct injection technology is emerging. b. electric valve and non-cam engines. Variable valve timing engine (Variable Valve Timing, VVT) is addressed in the conventional vehicle engine, due to the valve timing constant resulting in some important properties of the entire engine operating range can well meet the needs presented . VVT engine technology in the range of operating conditions to provide optimum valve timing, a better solution for high speed and low speed, high load and low load under power and economy of contradiction, while a certain extent, to some extent, improved the emissions performance. With environmental protection and sustainable human development requirements, low power consumption and low pollution has become a vehicle engine development goals. VVT technology due to its advantages, increasing attention has been attention, especially in today's rapid development of electronic technology, and promote the VVT technology from the research phase to the practical stage of development. Electric and electronic fuel injection valve has important significance, it will give the engine air system control and management cycle brings a series of changes in technology, such as canceling the throttle, variable compression ratio, cylinder deactivation and other parts. c. combustion mixture. Conventional spark ignition engine combustion process in the flame propagation, the flame front temperature than the unburned mixture is much higher. Therefore, this combustion process while the uniform mixture, but the temperature is still unevenly distributed, localized heat causes the flame formed in the region after the NOx. The diesel engine is the diffusion type combustion process, the combustion process burning rate determined by the mixing rate, the ignition occurs at many points, this type of combustion process are uneven mixing and combustion, NOx in the combustion zone generate a high temperature relatively dilute, thick solid particles in the fuelproduced high temperature zone. In homogeneous charge compression ignition (Homogeneous Charge Compression Ignition, HCCI) process, theoretically uniformly mixed gas and residual gas in the mixed gas by compression ignition, combustion is spontaneous, uniform and no flame propagation, This prevents the formation of NOx and particulates. The gasoline engine and diesel engine compression ignition homogeneous mixture combustion, the fuel technology and control technology, integrated two kinds of gasoline and diesel combustion mode HCCI HCCI advantages internal combustion engine technology is emerging. Third, the gas engineLiquefied petroleum gas (LPG), compressed natural gas (CNC), liquefied natural gas (LNC) and other clean energy for its automotive good economy and low emissions of pollutants, is considered to be the ideal vehicle engine alternative fuels, are widely Application. However, compared to traditional gasoline engine, a common mixed outside the cylinder gas engine volumetric efficiency low prevalence, power down the problems which restrict the further development of gas vehicles.3.1 Natural Gas EngineNatural gas engines into a single fuel gas engines and dual-fuel engines. Single fuel gas engines. Dedicated natural gas engines generally have a higher compression ratio, and use more fuel injection system and specially natural gas vehicles with catalytic converters. For example, Toyota has developed a 5S-FNE type NGV engine works: the CNG compressed gas cylinder out of the filter through the filter, the inflow pressure regulating device; Conditioned by the oil separator into the CNG injection system, a fuel injection Injection into the inlet of each cylinder.Dual fuel natural gas engines. Mainly in existing gasoline, diesel supplysystem based on the installation of CNG converted to diesel conversion, for example, fuel is injected into the system is only a small amount of diesel fuel for ignition of natural gas and air mixture.3.2 LPG enginesLPG engines into a single fuel, dual (switchable) fuel and dual-fuel (LPG and diesel) categories. Single fuel an engine fuel supply system is designed for the design of LPG fuel, and its structure to ensure efficient use of fuel gas. Dual fuel is converted in both fuel use, with two sets of fuel supply system, whether using LPG or petrol, the engine can work, the use of selector switch from one fuel to the engine to achieve another fuel conversion , use a mix of the two fuels is not allowed. Dual-fuel car engine work means using both fuels, generally with a small amount of diesel compression ignition ignition LPG and air mixture combustion is achieved, this diesel engine is also used pure work. The system has two types of fuel while the supply of cars equipped with two supply systems and two separate fuel storage systems. Based on the engine operating conditions, the fuel quality and engine parameters, while a certain percentage of LPG and diesel fuel supplied to the engine. Low load and idle automatically converted to pure diesel work.Fourth, fuel cell technologyFuel cell (Fuel Cell, FC) is stored in the fuel and oxidant electrodes through the chemical reaction directly into electrical energy generating devices. It is not through the heat cycle, thermal cycling without limitation, high energy conversion efficiency. Fuel can be hydrogen, methanol, ethanol, natural gas, coal gas, etc., battery emissions less environmental pollution. It does not require charging, as long as the external continuous fuel supply, electricity can be continuous and stable.。

T oward Higher Speeds and OutputsFrom the Small Diesel EngineD.BroomeRicardo & Co.Engineers(1927) Ltd.(England)THE AUTHOR’S company has long been concerned with the development of the small, high-speed diesel engine, and is particularly associated with combustion systems for this type of engine. Although such engines are not common in the North American continent, production and use in Europe and Japan is considerable, totaling several million units. These are, typically, naturally aspirated 4-cyl engines of 25-35 in3 (400-600cm3) displacement per cylinder, operating up to speeds of 4000-5000 rpm, with a limiting piston speed of about 2400ft/min(12m/s).In discussion with the U.S.Army Tank-Automotive Command (USATAC) at , Mich.it was proposed that the military requirement of high power from a small lightweight package could be achieved by exploiting higher speeds than hitherto, rather than the application of increased levels of turbocharger alone, and this led to the formulation of a research program to study combustion and breathing problems under such conditions. This paper describes the work carried out to date, which has involved the design, manufacture, and preliminary test work on special single cylinder engine.THE PROJECTThe project specifications finally laid down by USA TAC can be summarized as follows: 1.Design, procure, build, and test a single-cylinder engine of 3-1/2 in (88.9mm) bore andstroke, to operate at the highest possible speed, but certainly above 5000 rpm.Simulation of turbocharged conditions to be achieved using a separate air supply.2.To develop the single-cylinder test engine to achieve performance targets such that a4-cyl version for military duties could produce 1 bhp/in3(45.5kW/cm3) displacement with a target dry weight of about 3.5 lb/bhp (2.13kg/kW).3.The design not to be influenced by conventional practices, with the aim of minimizingmechanical and thermal stresses.4.Operation on CITE-R fuel (MIL-F-46005A (MR)) to be the primary requirement.Initially, fuels down to aviation gasoline were to be investigated, but this latter requirement was subsequently relaxed.5.Lubricating oils to the MIL-L-2104B specification to be used if at all possible.6.The final phase of the project to include a design study for a 4-cyl military engine,embodying the lessons learned on the single-cylinder test unit.7.Starting, idling, and light-load operation of the multicylinder engine must not becompromised.PRELIMINARY DESIGN CONSIDERATIONSA simple examination of the cylinder size and power output target rapidly showed the limitations that the maximum engine speed would have on performance (Table 1). Starting from the minimum speed specified of 5000 rpm, it is clear that speeds of 6000 rpm and above entail piston speeds equal to those of racing gasoline engines. While the reductions in bmep through use of high speeds are significant, the increases in fmep (estimated from past results obtained at the author’s company, much of which has been summarized in Ref.1) give very little return in reduced imep. Naturally aspirated automotive diesel engines working to the strict smoke limits of a few years hence can only operate up to about 145lb/in2 (1000kPa) imep; hence it was clear that some measure of turbocharging would be required. A further penalty of high speed and high engine friction is in fuel consumption, and Table 1 makes clear how the bsfc would worsen rapidly to levels no better than a gasoline engine, so losing one of the major advantages of the compression ignition cycle. In these circumstances,it was decided to limit the speed of the research engine to 6000 rpm.The major performance problems involved in the design of an engine to meet these requirements might be summarized as follows:ENGINE BREATHING-Previous experience on small high-speed diesels had shown that the major limitation on imep at high piston speeds is the breathing of the engine (2).Hence, valves of sufficient flow area had to be provided to allow efficient operation up to 3500 ft/min (17.8m/s) piston speed, some 50% higher than levels normally employed in diesel engines.This would certainly require departures from conventional cylinder head arrangements, involving inclined multiple-valve designs (Table 2);turbocharged operation brings a slight bonus in that the higher inlet air temperatures minimize pressure losses and reduce volumetric efficiency changes.In addition, possible turbocharger matching requirements had to be borne in mind. While, for automotive engines, torque backup requirements normally favor minimizing the available boost at the rated speed, so that a large exhaust valve area is not mandatory, in this case the very short absolute exhaust gas release periods suggested that the exhaust mean gas velocities should be kept low, and exhaust valve area about equal to that of the inlet.Also requiring consideration was the question of valve timings. For the inlet, high speeds are normally associated with a late closing point, yet in the case of a diesel, and with closing points later than about 45 deg abdc, there would be a progressive sacrifice in starting ability, as well as some loss of low-speed performance, which would further impair the natural torque backup characteristics of the engine. For the exhaust, the turbocharger matching requirement again dictates an early release of the gases on the expansion stroke, and timings later than about 60 deg abdc do not show to advantage at high speeds. While a long overlap period could contribute to reduction of exhaust gas and exhaust system component temperatures, such gains would be minimal at high speeds due to the very low quantity of scavenge air which might be passed relative to the trapped flow, and the mechanical problems of obtaining the piston/valve clearance would place a severe penalty on the combustion system. COMBUSTION PROBLEMS-A fundamental problem likely to affect the engine at the speeds contemplated was the likely duration of the ignition delay period. Ignition delay is a function of engine speed, compression conditions, and injection timing for a fuel of particular ignition delay is a function of engine speed, compression conditions, and injection timing for a fuel of particular ignition quality at normal running conditions (3),if factors related to the particular combustion chamber configuration in use are considered as being of second order. CITE-R fuel has a minimum specified cetane rating of 37,but the published data on engine delay using this fuel covered only low-speed conditions, and were not of direct use in predicting results at 6000 rpm. However, consideration of these available data, together withthe known performance of small high-speed engines operating up to 5000 rpm on gas oil (55 cetane), led to the estimates shown in Fig.1,for the lowest compression ratio which would allow acceptable starting (higher ratios would give excessive heat losses and maximum cylinder pressures).These suggested that unaided or true compression ignition operation at 6000 rpm was feasible on CITE fuel, although the light-load condition would require inlet manifold air temperatures to be maintained significantly above ambient-not an impossible requirement for a turbocharged engine.Injection periods being controlled by the injection system will depend on the latter’s type, but for practical reasons there could be no possibility of developing new systems for the project, to replace the conventional jerk pump arrangement. With a fixed orifice area nozzle, there would be considerable problems in passing the required full load quantity of up to about 60 mm3/injection at 6000 rpm at the required rate, yet obtaining satisfactory characteristics for idling, the turndown ratio being about 11:1.The effect of an extended injection period on combustion at the high speeds required could be very severe on a direct injection (DI) combustion system, where use of a fixed orifice nozzle would be inevitable. In addition to this problem the major difficulty of the DI was seen as the high mechanical loading, accentua ted by the higher smoke-limited fuel/air ratios (A/F) requiring higher boosts to achieve the target rating. While Ricardo’s earlier research work had shown that DI systems could be made to operate up to 4500 rpm naturally aspirated, on balance (see Table 3) the Comet swirl chamber system, developed over many years for the small high-speed commercial engine, was considered to offer greater potential for this particular application. The major problem foreseen was high thermal loading, although the unaided starting and the full multifuel capabilities were also less satisfactory than those of the DI: however, with built-in aids such as could be applied to the multicylinder engine, and with a restriction to CITE fuel, these latter were not considered to be too serious.At the start of the project, then, some consideration was given to the DI as an alternative, and in addition to test running under boosted conditions of an existing 4000 rpm single-cylinder research unit, designs were completed for a DI version of the test engine. Since that date, the increased pressure of noise, smoke, and particularly exhaust emissionslegislation, has increasingly favored the divided chamber system, and test work on the DI version is not now likely to take place.ENGINE FRICTION-Comparing the proposed multicylinder high-speed turbocharged engine with a conventional commercial engine of the same cylinder size and number, it was clear that the former would have a significantly higher fmep through the use of higher rotational and mean piston speeds. As already made clear in Table 1,this would pose serious problems in relation to the attainment of both the target output and an acceptable fuel consumption.Fig.2 shows how using a typical commercial engine fmep/speed curve from Ref.1, the estimated fmep of the high-speed multicylinder engine was obtained. In this estimate, some increase in the mechanical friction of the basic engine structure was assumed, since the turbocharged condition would increase cylinder pressures and require larger bearings to give acceptable reliability. In addition, inlet and exhaust pumping losses could add materially to the high-speed fmep, unless acceptable valve sizes could be maintained.By gasoline standards,then,the mechanical efficiency of the unit would be poor,but experience had shown that although attention to detail throughout the design could yield gains,these low levels were implicit in the project specification.SINGLE-CYLINDER TEST ENGINEBased on the considerations outlined, the definitive single-cylinder test engine was designed, the boundary operating conditions for the engine being: bore and stroke,3-1/2 in ф×3-1/2 in (88.9mmф×88.9mm);normal full-load speed range,3000-6000 rpm; and maximum cylinder pressure,2500 lb/in2(17.3Mpa).While the cylinder pressure limit may seem high by conventional standards, past experience has shown the dangers of designing such engines to low limits, and thus inflicting unforeseen limitations on the test program. In fact, originally, with possible work on a DI version in mind, a limit of 3000 lb/in2(20.7Mpa) was set, but as noted, this limit was later reduced for the Comet version.The Comet swirl chamber engine layout is illustrated in Figs.3-5, and the complete engine shown in Fig.6.Of the major components, the following may be said:CRANKCASE-The crankcase and rear-mounted timing case and cover are in gray flake graphite iron to BS 1452:1961 Grade 14,spigoted or doweled and bolted together. The crankcase design was adopted from that of the Ricardo E/6 variable compression ratio gasoline engine, which results in the presence of the front chamber of the crankcase unit, where the E/6 timing drive was situated. Three main bearings are use, all of lead-bronze bushing type, the center bearing being the thrust bearing. The rear bearing acts only as a steady bearing to the otherwise long extension of the crankshaft, the clearance being adjusted so that it cannot take the firing load off the center bearing.CRANKSHAFT-The crankshaft is a one-piece forging in nitriding steel to BS 970:1955 En 40c.The balance weights are integral, and balance only the rotating loads, since primary and secondary balancer shafts are fitted to the engine. All journal and pin surfaces are nitrided, the diameters of the three journals being 3,3,and 2-3/8 in (76.2,76.2,and 60.4 mm),respectively, from front to rear, and of the pin 2-5/8 in (66.6mm).CONNECTING ROD-To obtain the better material properties associated with a forging without the expense of special dies, a search was made of commercial engines, and the connecting rod of the Ford 2700 series diesel engine finally selected as the most appropriate. While satisfactory big-end bearing loadings were achieved at the 3000 lb/in2maximum cylinder pressures, the little-end design was considered inadequate, and the decision made to use this rod only for the Comet swirl chamber version of the engine, at a pressure limit of 2500 lb/in2. The bearings are as used on the 2700 series engine, that is ,15% reticular tin/aluminium half liners, the little-end bushing being a wrapped lead-bronze item. In addition to careful checking and polishing of the rod, the little end is reduced in width, the better to distribute the firing and inertia loads between the piston pin bosses and the little-end bushing.A higher torque than standard is used on the big-end setscrews, to prevent the cap lifting off due to the inertia forces at tdc exhaust, at 6000 rpm.Computer calculations carried out by the bearing suppliers, The Glacier Metal Co.Ltd., showed that the proposed bearing arrangements were acceptable, although the big end in particular has to accept very arduous conditions at high speeds due to the great inertia of the relatively massive connecting rod (Fig.7).The importance of correct form for both the pin andthe bearing under these conditions cannot be overstressed; this apart, the only problem that occurred was rapid cavitation attack in the top (loaded) half liner with the original clearance. The cause of this is evident in Fig.7,and a reduction in clearance to 0.0022 in (56μm) cured this trouble.PISTON AND WRIST PIN-The piston is a one-piece sand casting in 13% silicon aluminum alloy to BS 1490:1970 LM13WP,with the shallow trench and twin recesses of the Comet combustion system formed in one face of the angled (pent-roof) crown surface. Two compression rings are used, the top being a plain barrel-faced ring and the second a taper-faced internally stepped (twisted) ring; the slotted oil-control ring is of the conformable type. Rings are supplied copper-plated on the rubbing faces to assist in bedding in, but are not chrome-plated, since this facing is applied to the liner.The piston was designed deliberately of relatively great height, since it was feared that the very high (by diesel standards) piston speeds together with boosted operation would create difficulties in obtaining acceptable piston, ring, and liner conditions, and it was not thought desirable to accentuate problems more than was necessary. However, relatively little trouble has been experienced with the ring pack.Piston cooling and little-end lubrication is via an oil spray from a fixed jet located in the crankcase. This method was selected to avoid grooving the big-end bearing liner, which would have reduced its capacity. Two piston designs were developed, a tray-cooled arrangement and the soluble core design shown in the figures. To obtain acceptable cooling of the ring belt with the tray-cooled design, the struts transmitting gas loads from the crown to the wrist pin bosses were thinned as far as was thought practicable, but this arrangement was found to allow excessive distortion. The soluble core design has given excellent service to date.The wrist pin is of case-hardened steel,1-3/8 in (34.9mm) in diameter:CYLINDER LINER AND W ATER JACKET-The high rates of local heat transfer associated with the use of a swirl chamber combustion system, together with the 2500 lb/in2 maximum cylinder pressure limit, led to design difficulties with the wet-type cylinder liner, since calculations showed that a conventional iron liner of thickness adequate to withstand thegas loads would give excessive surface temperatures for acceptable lubrication at the top ring reversal point. The solution adopted was to use a steel liner, with the bore given the necessary surface finish before being plated with hard chrome to a thickness of 0.0015 in (38μm) by the Chromard process. Toward the top, the liner is thinned to provide the necessary temperature control, while the greater thickness lower down enhances rigidity to combat water-side attack. The liner is flanged at the top and seats on the cylindrical mild steel water jacket itself seating on top of the crankcase; radial location is provided by the liner spigoting in the crankcase, a water seal being obtained in the normal way by rubber O-rings.CYLINDER HEAD ASSEMBLY-The cylinder head, with its associated cambox, is the most complex single assembly of the engine, and presented considerable design problems. The most pressing of these centered on the provision of adequate valves and ports-the difficulties here may be appreciated when it is realized that ports suitable for a conventional engine of 5-1/2 in bore had to be provided on a 3-1/2 in bore-together with adequate cooling for the very high rating of 5.7 ihp/in2 (0.66 indicated kW/cm2) of piston area, this with a swirl chamber comber combustion system.The position of the Comet swirl chamber at the edge of the bore does not render the use of four valves very attractive, and although this and other possible layouts were examined, a 3-valve arrangement was finally adopted. A pent-roof head surface was necessary (Table 2), partly to obtain the necessary valve area but primarily to prevent excessive congestion higher up in the head. It is normally preferable to pair the exhaust valves to reduce their individual size and use a single large valve, but the opposite layout was finally chosen, as shown in Fig.8, since the paired valves had to lie in the center of the head and the intense heating of the head from the long port duct if this latter were the exhaust was considered unacceptable. Asymmetrical chamber/valye layouts were also investigated but rejected as offering no real advantages and being incompatible with multicylinder requirements. The so-called externally inserted form of the Comet chamber was adopted to minimize the space occupied by the hot plug forming the lower portion of the chamber.To cool the resulting four bridges ins the lower deck of the head, between the chamber and the inlet valves, and the inlet and exhaust valves, drillings were provided, giving an accuratelycontrollable metal thickness between the hot gases and the coolant, and a clean surface on the coolant side. The swirl chamber hot plug carrying the throat, and made from Nimonic 80A alloy by precision casting, is a light fit on its sides as well as locating on a copper gasket on its upper flange, since experience showed that at these high ratings some direct cooling was necessary, unlike commercial engines where an air gap is used to improve warm up after starting. The upper part of the chamber carrying the injector is a spheroidal graphite iron casting. A transducer tapping into the cylinder is provided at the front end of the head.The light alloy head seats directly on the steel liner flange, no gasket being employed, and is clamped by eight suds rooted high in the head and passing vertically downward through the water jacket top flange. No difficulties with gas blow have been experienced, and it has been found possible to operate with a head stud load of only 1.4 times the full gas load.Separate overhead inlet and exhaust camshafts are carried in a cambox casting secured to the head by 11 setscrews. The camshafts operate the valves via inverted bucket tappets, lash adjustment being by means of pallets placed on the top of the valve stems. Camshafts with alternative inlet closing and exhaust opening points are available. The inlet valves are of BS 970:1955 En 59 “XB” steel: 21-4/n austenitic steel was specified for the single exhaust valve, but at the high exhaust temperatures experienced, some head cupping occurs, and two-part exhaust valves with Nimonic 80 heads are now available. High chromium iron seat inserts are fitted to the head.Primarily because it was realized that to meet the weight target for the multicylinder engine, aluminum alloy would have to be used wherever possible, the head and cambox castings are in this material. Heads were originally cast in BS 1490:1970 LM25WP Al-Mg-Si alloy, but these castings were found to be porous in the inlet port wall. Improvements were made in the method of casting, and the material was changed to the high-temperature RR 350 Al-Cu-Ni-Co-Sb-Zr alloy. No further troubles with large scale porosity were experienced, but rapid cracking of the inlet/exhaust valve bridges than occurred. Metallurgical examination indicated the presence of shrinkage microporosity and films formed during casting, but in view of the seriousness of these failures, temperature measurements with a pair of fixed thermocouples symmetrically located at different depths just inboard of the bridge weremade-the preferred traversing type of thermocouple illustrated in Ref.4 could not be fitted in this instance due to physical limitations. These tests, given in Table 4,confirmed the original design calculations carried out according to the procedures also summarized in Ref.4, which indicated that while Lm25WP alloy should have been marginal for this duty, RR 350 was unlikely to fail simply by thermal fatigue alone. After making design modifications to improve the cooling of the bridges, as well as strengthening them by reducing the valve seat diameters to 1.050 in (26.7mm), and 1.505 in (38.2mm) for the inlets and the exhaust, respectively, mechanical loading tests were carried out at ambient temperature (that is ,cold), since it was known that some distortion of the head took place even during assembly. Miniature strain gages were fitted to the troublesome bridges prior to the fitting of the valve seat inserts, and the head completed, fitted, and torqued onto the engine, and the cylinder space pressurized to the design cylinder pressure, all while monitoring the gage readings. The results, compared with a similar set for a highly successful aluminum-headed 2-valve commercial diesel engine, are shown in Fig.9, and confirmed the existence of significant tensile strains in the bridges of both engines when cold, although these would be counteracted to some extent at least by the compressive thermal loads in the running engine. Analysis of the cold results on a Gerber diagram for the RR 350 material showed a significant safety margin even against fatigue data for elevated temperatures, and indicated no fundamental reason for the failures.The present head has, to date, completed over twice the number of hours needed to fail the earlier heads, and it would seem that these problems have been successfully overcome, and a viable head design developed.TIMING DRIVE AND BALANCER GEAR-The rear-mounted timing case houses an all-gear drive, downward to the two engine-speed primary balancers and the two twice-engine-speed secondary balancers, and upward to the half-speed drive. The balancer shafts, located beneath the crank throw, are formed from steel bar stock by milling away one side of the bar, over which is then pressed thin steel tube to provide a smooth external surface to reduce windage and oil churning. The half-speed output from the top of the timing case is forward via a coupling to the fuel injection pump and rearwards to a toothed belt sprocket.The two overhead camshafts are driven via this 1:1 toothed belt and a layshaft located on the rear of the head assembly; this layout gives flexibility to the head design and allows alternative chamber and valve layouts to be readily incorporated if required in the future. Ball and roller bearings are used throughout the timing drive system.FUEL INJECTION SYSTEM-As noted earlier, it was decided from the outset to use a conventional jerk pump fuel injection system, and a search was carried out for a 3000 rpm pump suitable for the application. The unit used is basically as developed for a 3-cyl, 3000 rpm, 2-stroke engine, the dynamics of the individual elements having been proved at the required speeds. To obtain the necessary higher injection rates and fuelings, a new camshaft was made up with all three cams in phase, so that individual elements could be coupled together hydraulically as necessary. The pump is driven via a manual advance/retard unit, to allow adjustment of injection timing without shutting down the engine.The location of the fuel pump adjacent to the water jacket allows a short high-pressure fuel pipe to be used, and a conventional S-size pintle nozzle is fitted to the injector. The design of nozzle heat shield developed for commercial engines is used to maintain low nozzle tip temperatures.COOLANT CIRCUIT-The necessary high coolant flow rates are provided on the test engine by an external, electrically driven pump, with a flowmeter in the main circuit. The engine circuit is a parallel system, however, with coolant fed to tow sets of entries. One set consists of two tangentially biased holes at the base of the cylinder water jacket, from where coolant flows spirally up past the liner and around the liner flange via a series of small cutouts in the flange support shoulder. Coolant then enters the head through 12 holes in the deck head inboard of the ring of securing studs-an O-ring provides the seal between the head and the water jacket. The second set of entries comprises the four drillings in the bridges in the cylinder head deck, the flows from which converge in the center of the head between the inlet valves before flowing outward around the inlet port duct to join the first coolant stream. Coolant exits from the head via a single take-off above the exhaust port.LUBRICATING CIRCUIT-Again, a separately driven pump is used to provide oil for lubrication and piston cooling; flowmeters allow the separate flows to be established. Alllubricant feeds are via separate drillings and external pipe connections, experience having shown that on this class of engine such a layout achieves maximum reliability with low primary cost. Low-pressure feeds are provided for the valve mechanism. The sump is “dry” and is slightly pressurized to ensure that oil does not build up around the balancer shafts.ENGINE PERFORMANCEDevelopment work on the engine combustion and injection systems is not complete at the present time, and no real work has been carried out to date to optimize the engine breathing. Hence, the result herein quoted are included essentially to show that the target performance requirements can be met, rather than to present the optimized performance of this advanced engine concept. Further gains are to be expected, particularly in the balance of performance over the speed range, and in addition it is hoped to obtain more data on combustion at ultra high speeds, and on the mechanical and thermal loadings involved.TEST INSTALLATION-The engine is coupled to a d-c electric swinging field dynamometer, which is also used for motoring the unit. Coolant outlet and lubricating oil inlet temperatures are automatically controlled via water-cooled heat exchangers. Boost air is supplied from a separately driven air compressor through an Alcock viscous flow airmeter and a heater/antisurge tank positioned close to the engine, to provide fine control of inlet air temperature and reduce ram effects. The exhaust is fed by a short pipe to an expansion chamber, the pressure therein being controlled at the outlet; provision is made at entry to the chamber or a range of orifices to be fitted, for use in simulating turbocharged operation during investigations of engine breathing. The test installation is shown if Fig.10.The normal method of test is to operate the engine over the load range at a fixed speed by varying the fueling, the inlet air (boost) and exhaust back pressure conditions being held constant and equal to one another. This does not simulate a turbocharged engine operating over the same load range, but from such results approximate predictions of turbocharged engine performance can be built up. Results are presented in terms of the indicated performance of the engine, derived from the brake results and the motored friction at the same。

柴油发动机喷射系统外文文献翻译、中英文翻译、外文翻译In the past five years。

there has been a XXX。

with the most significant change being the use of common rail XXX n diesel engines。

which is now receiving increasing n。

While there is also a trend towards direct XXX engines。

this XXX。

such as air n。

XXX.Keywords: fuel supply system。

common rail system。

XXX.The most basic n of any fuel oil supply system is to XXX。

XXX increase in vehicle n requirements。

precise control of the system has XXX。

the fuel oil supply system should not only change the cycle oil but also adjust the XXX.In the mid-90s。

carburetor XXX。

but the control aspect was not accurate。

After many improvements。

the carburetor was able to control each XXX and full XXX。

XXX。

XXX。

and XXX.XXX was common in the early 90s。

timing XXX improvement。

This led to the development of XXX driving。

pushing forward the European XXX.From the fuel system's point of view。

柴油机的工作顺序英语作文The diesel engine, a type of internal combustion engine, is renowned for its efficiency and power. Unlike gasoline engines, diesel engines operate on a different cycle known as the Diesel cycle, which involves a series of steps that transform chemical energy into mechanical work. Here is a detailed look at the working sequence of a diesel engine in English composition form.Intake Stroke:The first step in the diesel engine's operation is the intake stroke. The engine draws in air when the intake valve opens as the piston moves downward. Unlike gasoline engines, diesel engines do not inject fuel into the combustion chamber during this phase; only air is inducted.Compression Stroke:As the piston moves upward, the air inside the cylinder is compressed. The compression stroke is critical because it raises the air's temperature to a point where it is hot enough to ignite the diesel fuel without the need for a spark plug. Diesel engines typically have a higher compressionratio than gasoline engines, which contributes to their efficiency.Ignition (Injection) Stroke:At the end of the compression stroke, the temperature of the compressed air is high enough to ignite the diesel fueldirectly. At this point, the fuel injector sprays a precise amount of diesel fuel into the combustion chamber. The fuel ignites upon contact with the hot compressed air in a process known as 'autoignition.'Power Stroke:The power stroke is where the diesel engine generates its mechanical work. As the diesel fuel combusts, it rapidly expands, pushing the piston downward with considerable force. This movement of the piston turns the engine's crankshaft, which then converts the linear motion into rotational motion to power the vehicle or machinery.Exhaust Stroke:Finally, the exhaust stroke clears the combustion chamber of the spent gases. The piston moves upward, pushing the combustion byproducts—mainly carbon dioxide and water vapor—out through the open exhaust valve. Once the exhaust valve closes, the cycle begins anew with the intake stroke.Advantages of Diesel Engines:Diesel engines are preferred for their high torque, fuel efficiency, and durability. They are commonly used in heavy-duty vehicles, ships, and generators due to these characteristics.Environmental Considerations:While diesel engines offer many benefits, they also have environmental implications. They emit pollutants such as nitrogen oxides and particulate matter, which have led to the development of advanced emission control technologies toreduce their environmental impact.Understanding the working sequence of a diesel engine is fundamental to appreciating its design and functionality. Each step in the cycle is meticulously engineered to ensure efficient fuel combustion and reliable power output.。

作文分论点,新引擎英文回答：New engine.The development of new engines has always been an important aspect of technological advancement in various industries. In recent years, there have been significant advancements in engine technology, leading to the emergence of new engines that offer improved performance, efficiency, and environmental friendliness. In this essay, I will discuss the benefits of new engines and their impact on different sectors.Firstly, new engines are known for their enhanced performance. With advancements in engineering and design, these engines are capable of delivering more power and torque compared to their predecessors. This is particularly beneficial in the automotive industry, where high-performance engines are in demand. The improved performanceof new engines allows for faster acceleration, higher top speeds, and better towing capacity, providing a more enjoyable driving experience for consumers.Furthermore, new engines are designed to be more fuel-efficient. With rising concerns over environmental issues and the need to reduce carbon emissions, fuel efficiencyhas become a crucial factor in engine development. New engines incorporate advanced fuel injection systems, turbocharging, and hybrid technologies, which result in reduced fuel consumption and lower greenhouse gas emissions. This not only helps to protect the environment but also leads to cost savings for consumers in terms of fuel expenses.In addition to performance and fuel efficiency, new engines also offer improved reliability and durability. Through the use of advanced materials and manufacturing processes, these engines are designed to withstand harsh conditions and prolonged usage. This is particularly important in industries such as aviation and marine, where reliability is crucial for safety. The enhanced reliabilityof new engines ensures smoother operations and reduces the risk of breakdowns, resulting in increased productivity and reduced maintenance costs.Moreover, new engines contribute to technological innovation and economic growth. The development and production of new engines require extensive research and development, leading to the creation of new job opportunities and the growth of related industries. Additionally, the introduction of new engines stimulates market competition, encouraging manufacturers to constantly improve their products and invest in research and development. This not only benefits consumers by providing them with better options but also drives economic growth through increased productivity and innovation.中文回答：新引擎。

汽车动力方面介绍英文作文As we all know, the powertrain system is the heart of a car, and it is responsible for converting the energy from the fuel into the kinetic energy that propels the vehicle. In this essay, I will introduce the powertrain system of a car from several aspects.Firstly, let's talk about the engine, which is the most important part of the powertrain system. The engine is responsible for burning the fuel and generating power. There are several types of engines, including gasoline engines, diesel engines, and hybrid engines. Gasoline engines are the most commonly used engines in cars, and they are characterized by their high power output and smooth operation. Diesel engines, on the other hand, are known for their high torque and fuel efficiency. Hybrid engines, as the name suggests, combine the advantages of both gasoline and electric engines, and they are becoming more and more popular due to their excellent fuel economy and low emissions.Secondly, let's talk about the transmission system, which is responsible for transferring the power generated by the engine to the wheels. There are two main types of transmission systems, manual and automatic. Manual transmissions require the driver to manually shift gears, while automatic transmissions can shift gears automatically based on the vehicle's speed and load. In recent years, many car manufacturers have developed advanced automatic transmissions, such as dual-clutch transmissions and continuously variable transmissions, which can provide better fuel economy and performance.Thirdly, let's talk about the drivetrain system, which is responsible for transferring the power from the transmission to the wheels. There are several types of drivetrain systems, including front-wheel drive, rear-wheel drive, and all-wheel drive. Front-wheel drive is the most common type, and it is characterized by its compact size and good fuel economy. Rear-wheel drive, on the other hand, is known for its better handling and acceleration. All-wheel drive, as the name suggests, can transfer power toall four wheels, providing better traction and stability in all kinds of road conditions.In conclusion, the powertrain system is a complex and important part of a car, and it plays a vital role in determining the performance, fuel economy, and driving experience of the vehicle. Car manufacturers are constantly developing new technologies and improving existing ones to make cars more efficient, powerful, and environmentally friendly. As consumers, we should choose cars with advanced powertrain systems that meet our needs and preferences.。

英语发动机介绍作文Introduction to English Engines。

Engines are the heartbeat of modern transportation and industry, propelling vehicles, machines, and even power plants. Among the various types of engines, English engines stand out for their efficiency, reliability, and widespread use across different sectors. In this essay, we will delve into the intricacies of English engines, exploring their history, workings, and significance in today's world.The origin of English engines dates back to the Industrial Revolution, a period marked by unprecedented advancements in technology and manufacturing. It was during this time that engineers and inventors in England pioneered the development of steam engines, laying the foundation for the modern concept of engines. These early innovations, pioneered by figures such as James Watt and George Stephenson, revolutionized transportation and industry, driving economic growth and societal change.Over the years, English engines have evolved significantly, transitioning from steam power to internal combustion engines and, more recently, to advanced propulsion systems like electric motors. Despite these advancements, the principles that underpin English engines remain consistent – the conversion of energy into mechanical work to perform tasks ranging from powering vehicles to generating electricity.One of the defining characteristics of English enginesis their emphasis on efficiency and performance. Whetherit's a diesel engine in a truck, a gas turbine in a power plant, or an electric motor in a hybrid car, English-engineered powertrains are engineered to deliver optimal performance while minimizing fuel consumption and emissions. This commitment to efficiency aligns with broader societal goals of sustainability and environmental stewardship.Moreover, English engines are renowned for their reliability and durability, traits that are essential in demanding applications such as aviation, maritimetransportation, and industrial machinery. Through meticulous design, rigorous testing, and continuous improvement, English-engineered engines have earned a reputation for withstanding harsh conditions and operating reliably under extreme pressures.In addition to their technical prowess, English engines play a pivotal role in driving innovation and competitiveness in various industries. Companies likeRolls-Royce, Jaguar Land Rover, and McLaren Automotive are at the forefront of automotive and aerospace engineering, pushing the boundaries of what's possible in terms of performance, efficiency, and safety. Their relentless pursuit of excellence has cemented England's status as a global hub for engine development and manufacturing.Looking ahead, English engines are poised to play a central role in the transition towards sustainable transportation and energy systems. With the growing focus on electrification, hybridization, and alternative fuels, English engineers are spearheading efforts to develop next-generation powertrains that are cleaner, more efficient,and less reliant on fossil fuels. By embracing innovation and collaboration, the English engine industry is driving towards a future where mobility is not only efficient and convenient but also environmentally responsible.In conclusion, English engines represent a rich legacyof innovation, ingenuity, and engineering excellence. From their humble beginnings in the Industrial Revolution totheir present-day prominence in transportation and industry, these engines embody the spirit of progress and resilience. As we stand on the cusp of a new era of technological advancement, English engines will continue to serve as the driving force behind our journey towards a brighter, more sustainable future.。

Diesel Engines: Design and Emissions REVIEW OF A COURSE ON DIESEL PARTICULATES AND NO X EMISSIONSBy John PignonDiesel engines have major roles in automotive and stationary applications, both large (heavy duty) and small (light duty). Diesel engines are energy efficient, but their NOx and particulate emissions present major obstacles to engine development. This selective review of the course “Diesel Particulates and NOx Emissions” reports the latest developments taking place in diesel technology: engine design, fuel injection systems, fuel, lubricants, turbochargers, aftertreatment, emissions and health effects, that impact on particulate and NOx emissions.The course is run by the University of Leeds, Energy and Resources Research Institute.The “Diesel Particulates and NOx Emissions” course (1) is one of an ongoing series of professional development courses established about 20 years ago by Gordon E. Andrews, now Professor of Combustion Engineering at the University of Leeds, who identified a need for education in this field. The course was held at the Weeton Hall Hotel and Conference Centre, Leeds from Monday 23 to Friday 27 May; this series of courses is held both in the U.K. and the U.S.A. Lectures were given by Professors Andrews and David B. Kittelson (University of Minnesota) (2), and representatives of major industrial organizations and consultants involved in research into diesel technology. The thirty-nine attendees from industry and universities in the U.K., Europe and Asia, were mostly practitioners from a variety of backgrounds linked with diesel engines.EmissionsDiesel engines offer the possibility of combining very high thermal efficiencies with very low emissions, and their good fuel efficiency results in low carbon dioxide emissions. The main problem areas for diesel engines are emissions of nitrogen oxides (NOx) and particulates, and these two pollutants are traded against each other in many aspects of engine design. Very high temperatures in the combustion chamber help reduce the emission of soot but produce higher levels of nitric oxide (NO). Lowering the peak temperatures in the combustion chamber reduces the amount of NO produced but increases the likelihood of soot formation. Better mixing of the air and fuel is the key to lower emissions. The NO produced rapidly oxidises to NO2 (collectively called NOx). NOx combines with hydrocarbons or volatile organic compounds in the presence of sunlight to form low level ozone. This leads to smog formation.Professor Andrews, in his initial lectures, highlighted environmental problems and legislation. He stated that it is theoretically possible to run an engine with close to zero emissions of both NOx and particulates, but in practice, the way forward is a combination of close control of the combustion process, coupled with goodaftertreatment. Most control and trapping systems use platinum group metals. Fuel Injection SystemsRichard Andrews (Delphi, U.K.) talked about various methods of fuel delivery and injection systems. This is one of the rapidly changing areas of diesel engine technology. In the past, fuel systems were mechanical, and used injection pressures of 200–300 bar, with one fuel injection per power stroke. The resulting plume of fuel in the combustion chamber had a wide temperature range, due to poor mixing with the air. The combustion in the rich region of the flame produced soot, and the lean regions produced NOx.To overcome this, systems today operate at pressures up to 1500 bar and have up to 8 holes per injector. This requires the injection holes to be smaller. The fuel plumes in engines with multiple injection holes are smaller than those from a single large injector. The temperature profile across the plumes is far more limited; this reduces emissions and offers better air utilization within the cylinder. Andrews also discussed the design and implications of ever smaller injection holes and the increasing importance of hole geometry. He outlined the production problems created by this and reviewed some of the techniques used to overcome them.Mechanical pumps are still used in modern systems to generate the pressures, but the injection timing is now computer-controlled, and delivers very precise amounts of fuel.This has enabled the development of homogeneous charge compression ignition (HCCI) engines, which operate with up to six injections per power stroke. This combustion technology tries to lower the combustion temperature by forming a lean pre-mixture and burning it to reduce NOx and smoke.Systems in operation for the slower running heavy-duty diesel engines were explained. Due to scale, heavy-duty injection systems are built differently but still use a mechanical pump and electronic control.Engine Design and LubricationA large amount of data was presented regarding developments in engine design. As the combustion process becomes cleaner, the emissions caused by the lubricating oil become more significant. Diesel fuel is a very efficient solvent for lubricating oil, and great care is needed to prevent the fuel from contacting the cylinder walls, which are coated with lubricant, and dissolving the oil. This has led to changes in the shape of the combustion bowl within the piston and in the fuel injector configuration. Various combinations of these were discussed. In slower running heavy-duty diesel engines with large cylinders it is easier to prevent the fuel from hitting the walls of the combustion chamber. However, with smaller engines it is more difficult to prevent fuel from hitting the cylinder walls.Lubricating oil with its friction modifiers plays an essential part in the smooth running of an engine, but oil consumption is a big issue for particulate trap manufacturers, as the additives in oil produce particles of ash which can collect in the particulate trap (3, 4).Exhaust gas recirculation (EGR) systems were reviewed by Professor Andrews. Using EGR reduces the peak combustion temperature and hence the formation of NOx (5). In HCCI engines, EGR is used to control engine pre-ignition (engine knock). Further work on HCCI technology is expected to bring the diesel engine closer to Rudolf Diesel’s original idea of an engine running with a homogeneous charge but without peaks in temperature (6).TurbochargersA turbocharger increases the charge pressure, that is, the pressure of air in the cylinder before compression begins. Increasing the charge pressure allows the engine to operate on a leaner mixture resulting in lower particulate emissions. Owen Ryder and Henry Tennant (Holset Engineering, Huddersfield, U.K.) presented data on modern turbocharger design using compound charging and variable geometry turbochargers. Turbochargers are increasingly being fitted to diesel engines, and the need to integrate them into emission control packages was discussed. AftertreatmentNOx and particulate aftertreatment were discussed by Dennis Webster (Consultant in catalysis, Royston, U.K.) (7), who reviewed the need for the catalytic oxidation of gaseous compounds from diesel exhaust. The mode of operation of a platinum-containing continuously regenerating trap (CRT.) was described (5) and compared to the performance of direct thermal oxidation traps. Coated traps show activity at lower temperatures (light off at 250℃) giving a wider operating window. Gordon Andrews and Dennis Webster also presented a series of talks on selective catalytic reduction (SCR), discussing ammonia and hydrocarbon SCR. Both techniques involve adding a reductant to the exhaust stream, just prior to the catalyst. Hydrocarbon SCR, involving platinum-containing catalyst, uses the vehicle fuel, while ammonia SCR uses urea as the additive, urea decomposing to give ammonia.A system combining a platinum-containing oxidation catalyst, a diesel particulate trap, a SCR catalyst, urea as the reductant and a platinum-containing slip catalyst was shown. Andrews opined that this technology seems to offer a good solution to future NOx emission regulations. However, it suffers from having only a narrow operating window, with little or no activity at low temperatures; this is often experienced during test cycles and in the real world. Further work is required to increase the width of the operating window, especially at the low temperature end.NOx-trap technology, containing platinum-rhodium catalyst and originally developed for gasoline direct injection (GDI) applications, is being considered for diesel engines (5). The low sulfur tolerance and the need for a rich spike to regenerate the trap has always been a drawback, but some promising materials are now emerging. A NOx-trap incorporated into a particle filter seems to offer a solution as the trap removes the particles generated during the rich spike. Ultra low sulfur fuels are essential for this technology (8), and oil companies are working towards a world standard for diesel fuel.Particle Monitoring and Health EffectsProfessor Kittelson presented the results of measurements of particles in the atmosphere on or near roadways, and discussed their nature and formation. These particles cannot be accurately measured in the tailpipe, as up to 90% of the particle number may form and grow after they leave the tailpipe and as the exhaust dilutes into the atmosphere. Particles continue to form up to 2 seconds after leaving the vehicle. Atmospheric dilution leads to nucleation of particles.Particle measurement equipment and sampling techniques were described and there was a guide to problems encountered.Summing-UpThis course succeeded in covering a wide subject area in just five days. These courses have been, and are, a major contribution to disseminating information about, and raising the profile of, diesel technology. The amount of data dispensed to the delegates is large, and the lectures are well structured and presented. The course gives a fascinating insight into modern diesel engine technology. It is excellent value for money and is thoroughly recommended.References1 /fuel/shortc/sc.htm2 /centers/cdr/cdr_about.html3 A. J. J. Wilkins, Platinum Metals Rev., 2004, 48, (1), 444 A. J. J. Wilkins, Platinum Metals Rev., 2003, 47, (3),1405 M. V. Twigg, Platinum Metals Rev., 2003, 47, (4), 1576 Rudolf Diesel, U.S. Patent 608,845; 18987 Platinum Metals Rev., 1981, 25, (3), 112; D. E Webster, ibid., 1995, 39, (2), 73; ibid., 1994, 38, (3), 109; ibid., 1991, 35, (2), 948 A. J. J. Wilkins, Platinum Metals Rev., 2003, 47, (2), 96。