What is the reason why there is engine oil at the accelerator of the car?

Because the piston and cylinder of the engine are not sealed and have gaps, and because of high temperature and high pressure, there is engine oil. This needs cleaning.

1

The piston and cylinder wall of the engine are not absolutely sealed, but there is a certain gap. When the pressure in the compression stroke and the power stroke cylinder rises, some gas will inevitably escape from between the piston and the cylinder wall to the crankcase. This is called "jumping". Because the frequency of cylinder compression work is very high when the engine is running, the amount of gas escaping into the crankcase is not small. If left untreated, the pressure in the crankcase will increase, causing some abnormalities in the engine.

2

In the early days, people didn't pay attention to environmental protection, so the most direct method was adopted to solve the problem of crankcase blowby, that is, an exhaust pipe was set on the crankcase to discharge blowby gas directly into the atmosphere. However, it was later found that there were many harmful substances in the crankcase exhaust gas, which would pollute the environment if discharged directly, so the crankcase ventilation system was born. However, the place where the air filtered by the air filter and passed through the air flow meter can be obtained on the engine is the intake hose between the throttle valve and the air flow meter.

When the engine is running normally, the air is filtered by the air filter, and then the flow is measured by the air flowmeter. After that, part of the air enters the cylinder from the throttle through the intake manifold, and the other part enters the crankcase through the ventilation pipe of the crankcase ventilation system, and the corresponding amount of exhaust gas in the crankcase is sucked into the cylinder.

three

After the engine is turned off, the crankcase ventilation system no longer works. Because the engine oil in the crankcase circulates at high temperature for a long time, the crankcase has already been covered by various floating mist oil droplets. Because the temperature in the crankcase is very high, the higher the temperature, the higher the pressure, so the waste steam wrapped in oil droplets begins to move in all directions under pressure. Part of it will come to this position between the throttle and the air flow meter along the ventilation pipe, where the high-temperature steam and oil droplets will gradually cool down and become liquid, and these things will accumulate more and more, and eventually a lot of oil will be saved, which is what we can see with our naked eyes.

Oil appears on the accelerator of a car because there is a gap between the engine and the cylinder of the car. Because of the high temperature and high air pressure, the oil is visible to the naked eye.