Seeking introductory knowledge of driving

Necessary knowledge of automobile maintenance apprentice

1. The basic structure of an automobile consists of four parts: engine, chassis body and electrical equipment.

Two. Four-stroke gasoline engine is composed of engine block, crank-connecting rod mechanism, valve train cooling system, lubrication system, fuel system and ignition system (diesel engine has no ignition system).

3. The working process of four-stroke gasoline engine is divided into four processes: intake, compression, operation and exhaust. The four-stroke engine completes these four processes in four strokes when the piston moves up and down.

4. The function of engine block and crank-connecting rod mechanism is to convert the pressure of gas acting on the piston top when fuel is burned in the cylinder into the torque of crankshaft through the connecting rod, so that the crankshaft drives the working machine to do work. The main components of engine block and crank-connecting rod mechanism are cylinder block, cylinder head, piston, connecting rod, crank and flywheel.

5. The function of the valve train is to open and close the intake and exhaust valves in time according to the needs of the work, introduce combustible gas into the cylinder, and discharge waste gas in time. At the same time, it drives the distributor, gasoline pump and other components to work. The main components of the valve train include: intake valve, exhaust valve, camshaft transmission parts, etc.

6. The function of the cooling system is to dissipate the heat of high-temperature parts into the atmosphere to keep the engine working at normal temperature. Water cooling system is generally composed of engine water jacket, water pump, radiator, fan, thermostat, water thermometer and drain switch.

Seven. The normal working temperature of water-cooled engine should be 80-90 degrees. Take Jiefang CA 10B car as an example for engine temperature. According to the engine temperature, we can pull out (that is, open) or push out (that is, open and close) the shutter operating handle in the cab, and change the amount of air entering the radiator, thus adjusting the engine temperature.

8. The function of lubricating oil: lubricate all friction parts, reduce friction resistance and power consumption. Cooling effect: oil circulates, which can take away the friction belt. Reduce the temperature of parts. Cleaning function: wash away impurities on the surface of machine parts to reduce wear and tear. Sealing function: keeping the oil layer between the piston and the cylinder wall can increase the sealing performance.

9. Observe the oil pressure gauge on the dashboard of the cab: the normal oil pressure of the gasoline engine is 200-500 kPa；; Diesel engine 600- 1000 kPa.

10. The structure of carburetor can be divided into five devices: starting device; Idling device; Medium load equipment; Full load device; Accelerator. The function of carburetor is to vaporize gasoline according to the needs of engine in different situations, and mix it with air in a certain proportion to form combustible mixture. Timely and appropriate into the cylinder.