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1、汽车构造重点（Key automotive construction）Automobile structure are summarizedThe same point 1, four stroke diesel engine and gasoline engine and different points.Answer: the same point: each cycle through the intake, compression, power and exhaust stroke four.Different points: (1) the combustible mixture f
2、ormation in different ways: gasoline engine in cylinder air-fuel mixture,The diesel engine is inhaling pure air, combustible mixed gas of diesel engine is formed close to the end of the compression ignition (2);In different ways: gasoline engine is at the end of the compression ignited by an electri
3、c spark, the diesel engine is a compression ignition; (3) compression ratioDifferent; (4) the different fuel supply system.2, why should be reserved for the valve clearance? Why is too large or too small are not good?Answer: because when the engine works, the valve will be expanded as the temperatur
4、e rises, cause the valve is not tightly closed byLeak engine compression and power stroke, so that the power down, dont even start easily when serious.The clearance between the transmission parts and valve and valve seat collision sound, accelerated wear, but also makeThe duration of valve opening i
5、s reduced, the deterioration of inflation and exhaust conditions of the cylinder. The gap is too small will occur in the hot stateLeakage, power down, and even burned valves.3, diesel engine, gasoline engine in combustible mixture formation differs from the ignition mode? Why not the compression rat
6、ioThe same?Answer: gasoline engine in cylinder air-fuel mixture, diesel engine intake. Pure air, combustible mixed diesel engineThe gas formed close to the end of the compression. At the end of the gasoline engine is compressed by electric spark ignited, diesel engine is a compressionSpontaneous com
7、bustion. Therefore, diesel fuel injected into the cylinder, in a very short period of time is mixed with air immediately by burning itIt is because the two different ways of ignition, resulting in diesel engine needs a higher compression ratio.What is the role of the 4 engine, forced circulation wat
8、er cooling, and the circulating water.Answer: role: to improve the coolant pressure by pump, forced circulating cooling fluid in the engine.Circulating water: water pump, water pipes and water bodyUp / downThrough the radiator thermostat through the cylinder head jacket5, the engine temperature is t
9、oo high or too low, what harm?Answer: (1): high temperature metamorphic lubricating oil, the oil film parts cant keep normal; (2) heating partsThe expansion is too large and the destruction of normal clearance; (3) to the mechanical properties of metal materials decreased, so that can not affordThe
10、normal load.Low: (1) fuel evaporation, combustion quality deterioration; (2) the oil viscosity increases, the friction loss and; (3) increase the corrosion wear of the cylinder.These adverse consequences will lead to reduction of engine power, economic deterioration, loss of life.7, the composition
11、of overhead type gas distribution mechanism, how it works?Composition: the valve group comprises a valve, valve guide, valve main spring, valve spring retainer, valveThe transmission group comprises a rocker shaft and rocker arm, push rod, camshaft, tappet, timing gear.When working, the crankshaft d
12、rives the camshaft rotating through the timing gears, cam projections from the top of the tappet, throughThe push rod rocker swing, compress the valve spring, the valve from the seat (or valve opening), cam projections fromAfter opening, the valve closed by spring force.8, the ignition advance angle
13、 on engine performance impact, how to realize its adjustment.When the valve opening, speed increased, w increased, ignition angle, or continue to work forProcess, the dynamics of economic decline. A certain speed, load increases, solar term door opening increases, the concentration of the mixed gas.
14、High combustion speed increases, advance angle decreases.Adjusting device: centrifugal advance adjusting device, it can automatically adjust according to changes in engine speed; reallyAir ignition control device, it can automatically adjust with the change of load.How to penetrate the generated vol
15、tage ignition system of gasoline engine, 9?By connecting breaker periodically and cut off the ignition coil primary circuit, a current changes,In order to generate high voltage in the two winding of the ignition coil, and then by the distributor according to the working time of cylindersIn order to distribute the spark plug of each cylinder.What are the main drive system of 11. car assembly? And then tell their role.Answer: automotive transmission system is composed of a clutch, gearbox, universal transmission device and drive axle.The basic function of the clutch:(1) in the car started, b
