Analysis from China Quality Miles;
What's with burning engine oil?
China Quality Miles website introduced in an article that, under normal circumstances, the phenomenon of "burning engine oil" in the car will cause the oxygen sensor of the vehicle to be damaged too quickly, which will lead to the increase of carbon deposition in the combustion chamber, unstable idle speed, weak acceleration, rising fuel consumption and excessive exhaust emissions. In severe cases, the engine is not lubricated enough, resulting in irreparable damage or even scrapping of the engine, which leads to a substantial increase in maintenance costs and even potential accidents.
What about burning oil? Explain that the car has exceeded the normal oil consumption. The standard defined in China is that the oil consumption per 1000 km should not exceed 0.5 liter.
We should understand that not all oil consumption is called burning oil. Because the engine itself cannot fundamentally eliminate the consumption of engine oil. Everyone should have experienced such a life scene, greasy plates or bowls. Even if you scrape with a spoon or knife, the oil will never be clean. This is like two oil rings on the piston, which can never scrape off the oil on the cylinder wall.
Under normal circumstances, the phenomenon of "burning engine oil" will lead to the rapid damage of the oxygen sensor of the vehicle, which will lead to the increase of carbon deposition in the combustion chamber, unstable idle speed, weak acceleration, rising fuel consumption, excessive exhaust emissions and other adverse consequences; In severe cases, the engine is not lubricated enough, resulting in irreparable damage or even scrapping of the engine, which leads to a substantial increase in maintenance costs and even potential accidents.
If your car burns oil, the symptoms are mild. When the car is driving around 1000-2000 km, more carbon deposits appear in the exhaust pipe, and the oil indicated by the oil meter is lower than the normal scale or can't be seen. So serious combustion is that blue smoke has come out of the exhaust pipe. For example, the picture below is like this:
What is the reason why German cars burn engine oil?
In the engine cylinder processing technology of German cars, the cylinder wall of the engine is reticulate under the microscope (usually the cylinder wall is bright with naked eyes), and every tiny mesh is a "small oil depot" for storing engine oil. When the piston runs up and down in the cylinder, the lubrication performance is better than that of the plane cylinder wall, and the wear between the piston ring and the cylinder wall is minimized.
In addition, the piston ring of German cars has better toughness and weaker tension than that of Japanese cars. This matching naturally reduces the wear of the piston ring on the cylinder wall when it moves up and down. Therefore, after driving hundreds of thousands of kilometers, the wear of the cylinder wall of the engine is much smaller than that of other cars, and the engine can still maintain a good working condition (mainly referring to the cylinder pressure).
However, the phenomenon of Japanese cars burning engine oil is really much less, because their piston rings are more flexible and easy to clean up carbon deposits. However, the possibility of cylinder wall wear increases, even leading to overhaul.
In fact, that is to say, German luxury brand models are usually easy to burn oil, but the engine needs to be overhauled when it reaches 300,000 kilometers. Japanese luxury brand models are not easy to burn oil at ordinary times, but the engine needs to be overhauled when it reaches 200 thousand kilometers.
Is it easier for turbocharged engines to burn oil?
Many riders have this feedback: turbocharged engines burn oil more easily than naturally aspirated engines, and even 1000 km can consume 1 liter or even more oil in serious cases. However, naturally aspirated engines rarely burn oil. Why?
In fact, unlike naturally aspirated turbine engines, the compression ratio is variable and fixed when the engine is not supercharged at low load. When the engine is supercharged with high load, the compression ratio is no longer the original parameter because the cylinder is supercharged forcibly, which is also the reason why the turbocharged engine needs to increase the grade gasoline.
Therefore, the main reason for the high fuel consumption of German turbo cars is not the piston ring wear that everyone thinks. The water temperature of German cars is higher than that of Japan, and the aging of turbocharged high-temperature and high-pressure valve oil seal is the main reason for the high fuel consumption. Moreover, the application of turbocharged engine really controls the exhaust emission well. Under the premise of not changing the exhaust volume, the engine can use the turbocharger to increase the intake volume of the engine and improve the engine power. For example, 1.6T engine has higher power output than 2.0 naturally aspirated engine, but lower fuel consumption than 2.0 naturally aspirated engine.
Every coin has its two sides.
For example, when the engine with turbocharger is running, the cylinder temperature and combustion chamber pressure of the engine are much higher than those of the naturally aspirated engine, which affects the service life of the engine, and the engine with turbocharger is more complicated in structure and increases the maintenance cost.
Can German car burning oil be improved?
From the above article, we can also know that the cylinder wall of German cars is meshed, and when the piston does work (ignition and deflagration), it will burn off the residual oil in the mesh. This design will be relatively suitable for European and American countries. After all, the road conditions in Europe and America, especially in the European Union, are generally good, the engine can run at high speed, the cylinder wall network (small oil depot) stores less oil and burns less oil naturally.
But the road conditions in our country are much more complicated. For example, traffic jams cause vehicles to drive at a low speed for a long time, which will make more oil reach the cylinder network and naturally burn more oil. This is just like why a car should save fuel when running long distances, and it is a truth to save fuel when driving in cities. From a technical point of view, this kind of burning oil is an effective protection for the engine cylinder wall.
It is understood that the current standard of German automobile manufacturers is fuel consumption ≤0.8 liters per thousand kilometers. China should also formulate this standard, that is, the fuel consumption per thousand kilometers should be ≤0.3 liters.
German cars that are still burning engine oil can be properly replenished when the engine oil consumption reaches a certain level, or the oil change of the original factory 1 10,000 km can be shortened to 5,000 ~ 7,000 km. With the increase of automobile mileage and smooth wear of cylinder wall, the amount of oil burning will be less and less.
Based on China's viewpoint that quality travels thousands of miles,
1. The truth of burning oil in German cars: the design should be like this, protecting the cylinder;
2. The truth that Japanese cars don't burn engine oil: this is the design, sacrificing engine life;
3. The reason is different, and the life of the engine is different. Therefore, German cars are usually easy to burn oil, but the engine needs to be overhauled when it reaches 300,000 kilometers. Japanese cars are not easy to burn oil at ordinary times, but the engine needs overhaul when it reaches 200 thousand kilometers.
What about burning oil?
Cold automobile combustion engine oil
When the temperature of the car is not fully warmed up, a lot of blue smoke comes out from the exhaust pipe of the engine, but it will be normal after the car is warmed up. This phenomenon is caused by the aging of the valve oil seal. Due to the temperature drop, the rubber valve oil seal becomes stiff and cannot be completely sealed, and the above phenomenon occurs after the oil leaks from the valve to the combustion chamber for combustion.
Solution: Remove the engine cylinder head and replace the valve oil seal (please rest assured that this is a medium repair project. The maintenance time is about 4-5 hours. The cost is in 800 yuan-1200 yuan, depending on your car).
High temperature automobile engine oil
After the car reaches room temperature, the exhaust pipe still emits blue smoke, indicating that the piston ring has poor sealing. Due to the poor sealing of the piston ring, the oil directly enters the combustion chamber through the leakage of the piston ring under the action of the oil pump, and the exhaust pipe emits blue smoke. There are many reasons for this phenomenon, such as material aging, carbon deposit blockage, excessive wear of cylinder liner and so on.
Solution: According to the normal operation method, the engine needs to be hoisted for maintenance. The maintenance time is about 2-4 days. The cost ranges from 5000 yuan to 20000 yuan, depending on your car. The cost is mainly on accessories.
There is another solution: if it is determined that the engine oil is burned by a hot car, and it is not very serious (for safety reasons, the cylinder pressure test can be carried out first), the oil pan can also be directly removed, the piston can be directly taken out, and the piston ring can be replaced, so that the cost and time are similar to those of the first solution.