1.These parts can be grouped into four major categories; body, engine, chassis and electrical system.2.The internal combustion engine is most common; this obtains its power by burning a liquid fuel inside the engine cylinder.3.The chassis includes the power train, steering, suspension, and braking systems.4. A power train can include a clutch for manual transmission or a torque converter for automatic transmission, a transmission, a drive shaft, final driveand differential gears and driving axles.5.Basic types are: leaf springs, coil springs and torsion bars.6. A basic ignition system consists of the battery, low-lension cables, the ignition coil, distributor, coil high-tension cable, spark plug cables and sparkplugs.7.The operating strokes are: induction stroke, compression stroke, power stroke, exhaust stroke.8.The major parts of engine are engine block, engine heads, pistons, connecting rods, crankshaft and valves.9.These systems are the fuel system, intake system, ignition system, cooling system, lubrication system and exhaust system.10.The dry clutch mechanism includes three basic parts: driving member, driven member and operating members.11.The spur gears are mounted on four shafts: primary shaft (input shaft), layshaft (countershaft), mainshaft, and reverse idler shaft.12.The three types of braking systems are in use today: service braking system, parking braking system and additional retarding-braking system.13.It has five basic parts: the receiver, expansion valve, evaporator, compressor, and condenser.14.The three normally adjustable angles are caster, camber, and toe.段落一．Elements of the Power TrainThe elements of the power train must meet the following requirements;1)enable driving away,2)convert torque and speed,3)enable different directions of rotation for driving forward and backward,4)transmit tractive and pushing forces,5)permit different rotational speeds of the drive wheels when cornering,6)guarantee optimum operation of the engine (or electric motor ) in terms of fuel consumption and exhaust emissions.Standstill, driving-away and power interruption are made possible by operation the clutch .During driving away, the clutch slips and bridges the difference in rotational speed between engine and power train. When different operating conditions call for a shift of gear, the clutch separates the power train during shifting.Engine torque and engine speed are converted in the transmission in accordance with the tractive-power demand of the vehicle. The transmission design is influenced by the position of the engine and driven axle. Overall conversion takes place usually in a manually shifted transmission with variable transmission ratios and in a final drive with a constant transmission ratio. Nowadays, positive-locking transmissions with toothed gears as the most important elements are of even greater significance than non-positive friction-type transmissions.Two types of toothed-gear transmission are predominant: spur-gear transmissions of the countershaft type as manually shifted transmissions, and planetary-gear transmissions as power-shift transmissions. In addition, transmissions permit the different directions of rotation required for driving forward and backward.Final drive turns the drive through 90°and reduces the speed of the drive by a set amount to the vehicle.The differential provides for the equalization of the different axle and wheel speeds when cornering and for uniform distribution of the drive torque.二.The Hydrodynamic Coupling1. Hydrodynamic CouplingConventionally, the hydrodynamic coupling, also known as the Fötttinger coupling, has an impeller and a turbine wheel with vanes that usually extend in the radial direction. The impeller is often expanded to form a housing which surrounds the turbine. Since, due to the absence of an inner ring, there is no possibility of diverting the oil flow, the turbine torque is equal to the pump torque;公式Therefore 公式The index number depends on the design, the vane angle and the degree of filling of the coupling. The main working area of an hydrodynamic coupling is at v=0.9.2. Hydrodynamic ConverterThe hydrodynamic converter, also known as the Trilok or Fötttinger converter, is capable of operating in two phases: with torque increase in the first phase, and as a hydrodynamic coupling in the second phase. The usual design has three impellers:1) The pump, which is connected to the engine, acts like a centrifugal pump to produce the flow energy of a fluid.2) The turbine, which is connected to the transmission input, converts the flow energy back into mechanical energy.3) The reactor between turbine and pump diverts the flow of the fluid.Thus, the torque output is higher than the pump torque input from the engine. The torque increaseμμ=Mt/Mp is all the higher, the greater the speed difference (slip）between the pump and turbine. Withυ=0, i.e. with the turbine braked to a standstill (stall point, drive-away point), torque conversion reaches its maximum value and falls virtually linearly with rising turbine speed to a torque ratio of 1:1 at the coupling point. Above the coupling point, the reactor, which is supported on the housing by a one-way clutch, runs, torque-free, in the flow. Thus, the converter is now a clutch without torque conversion.For automobiles, the vane geometries are such that, at the drive-away point, the maximum torque increase μA is between 2 and 2.5. The hydraulic efficiencyηhydr=υμis similar in the conversion range to the speed ratioμand reaches values around 97% at high speed.Fluid couplings form the input element of automatic transmissions (in conjunction with planetary-gear trains, clutches, brakes and one-way clutches) and also of manually shifted transmissions in the form converter and clutch unit.三．Constant-mesh TransmissionFig.3-6 illustrates the flow of torque through a typical constant-mesh transmission. This type uses helical or double helical gears which are always in mesh. The mainshaft gear wheels are mounted on bearings and when a gear is required the mainshaft gear is locked to the shaft by a dog clutch.Although the mechanical efficiency is lower the helical gears are quieter and any damage resulting from a bad gear change occurs to the dog teeth instead of the actual gear teeth.元素的力量训练动力传动的要素必须符合下列要求;1)使开车逃走,2)把转矩和速度,3)使不同方向的旋转带动向前和向后,四)推进传送叶轮力量,5)允许不同转速时的驱动轮转弯时,六)保证了优化运行的引擎(或电机)从油耗和尾气排放。
