What are the causes of noise and vibration of diesel engines?

The most common cause of automobile jitter is that the throttle valve is too dirty or the fuel injector has too much carbon deposit. When there is too much carbon deposit in the engine, the gasoline sprayed by the fuel injection head will be absorbed by the carbon deposit during cold start, which leads to the lean mixture during cold start and makes it difficult to start. In this case, only when the gasoline adsorbed by carbon deposits is saturated, it is easy to run into the car. After running into the car, the gasoline adsorbed on carbon deposits will be sucked into the cylinder by the vacuum suction of the engine for combustion, which will thicken the mixture and dilute the combustible mixture of the engine, resulting in idling jitter after cold start.

The lower the temperature, the more oil is needed for cold start, and the existence of carbon deposit will affect the smooth start. Solution: clean the oil circuit, check whether there is carbon deposit in the idle motor, and clean it.

2, the ignition system problem

Check the working conditions of spark plugs, high-voltage lines and ignition coils. The ignition system is not easy to use, and the spark plug is not in good condition, which will also lead to this failure. Solution: Check whether there is too much carbon deposit in the spark plug and replace the spark plug.

3. The oil pressure is unstable

If you clean up the engine carbon deposit, clean the throttle, change the oil pad and spark plug, etc. You still find the car body shaking at idle speed. I suggest you go to the 4S shop to check whether the oil supply pressure and intake pressure sensors are normal. If the oil supply pressure of the oil pump is abnormal, or the intake pressure sensor has an incorrect value or works poorly, it will cause the body to shake. Solution: Check the oil pressure and replace parts if necessary.

4, engine parts aging

Car jitter is also related to the aging of engine feet (also known as claw pads). The engine foot is actually the damping system of the engine. The engine foot is responsible for absorbing slight vibration when the engine is running. If there is something wrong with the engine foot, these vibrations will be transmitted to the steering wheel and cab, causing idling jitter.

Diesel engine is an engine that burns diesel oil to obtain energy release. It was invented by German inventor Rudolf Dissel in 1892. In memory of this inventor, Diesel engine is represented by his surname diesel, and Dieselengine is also called diesel engine.

The advantages of diesel engine are large torque and good economic performance. Each working cycle of diesel engine also goes through four strokes: intake, compression, work and exhaust. However, because the fuel used by diesel engine is diesel, its viscosity is higher than that of gasoline and it is not easy to evaporate, but its spontaneous combustion temperature is lower than that of gasoline, so the formation and ignition mode of combustible mixture are different from that of gasoline engine. The main difference is that the mixture in the cylinder of diesel engine is compression ignition, not ignition.

When the diesel engine is working, air enters the cylinder. When the air in the cylinder is compressed to the end, the temperature can reach 500-700℃ and the pressure can reach 40-50 atmospheres. When the piston approaches the top dead center, the high-pressure pump on the engine injects diesel into the cylinder at high pressure, and the diesel forms fine oil particles, which are mixed with high-pressure and high-temperature air. The diesel mixture burns itself and expands violently, generating explosive force and pushing the piston to do work downward. At this time, the temperature can reach 1900-2000℃ and the pressure can reach 60- 1000 atmospheric pressure, and the generated torque is very large.

References:

Baidu encyclopedia entry diesel engine