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.。
