In January 2018, Honda CR-V owners in the Northeast region successively discovered that their vehicles had an increase in engine oil and oil emulsification. In February 2019, Toyota owners also discovered such a situation. Why "increased engine oil"? "Engine oil emulsification" breaks out in high latitude areas around the Spring Festival? Is this a patent for Japanese cars? Which car will be exposed to problems next year? Today, let’s compare the similarities and differences between Toyota and Honda’s increase in engine oil, and then talk about whether this phenomenon is an exception.
In terms of gender, time and place, both occurred around the Spring Festival, and both occurred in high latitude areas. Spring has not yet arrived in the Northeast around the Spring Festival, and the cold air from Siberia still affects the temperature in the Northeast. However, the increase in air humidity provides the necessary conditions for the water vapor and low temperature required to increase the amount of engine oil. Secondly, the Northeast region has taken the lead in promoting the use of ethanol gasoline. Compared with pure gasoline, ethanol gasoline has a greater water content, and the water vapor after combustion is also greater. Of course, the combustion is cleaner. This inevitably leads to a greater water vapor content in the crankcase blow-by gas, which in turn aggravates the increase in engine oil volume. However, what is mentioned here is only a very small amount of increase. As long as the engine can run at normal oil temperature for a long time, this increased part will be discharged with the crankcase ventilation system. This is not a Toyota patent, all engines will have this phenomenon, and a very small increase will not affect the performance of the engine.
The difference is the technical difference between the two. Honda's 1.5T Earth Dream engine is also the most advanced complete engine power technology in the world. It uses a turbocharged engine with direct injection and Atkinson cycle. Through in-cylinder direct injection, Atkinson cycle and turbocharging, the engine thermal efficiency and fuel economy are improved.
The main reasons for the increase in engine oil are in-cylinder direct injection technology and higher cylinder pressure. When the engine is at low temperature, low load and cold start, the rich mixture provided by the fuel injector and intake valve according to the cold engine start logic will not be in a good mixing state. Even at low temperatures, the "wet wall phenomenon" in which atomized fuel recondenses into liquid fuel and hangs on the cylinder wall may occur. This is the source of liquid fuel that enters the crankcase at low temperatures.
The application of turbocharging technology also brings higher cylinder pressure, which to a certain extent intensifies the re-condensation of atomized fuel. Therefore, the increase in oil in Honda's 1.5T Earth Dream engine has a certain relationship with the characteristics of the direct injection engine. Similarly, Volkswagen's turbocharging and direct injection power will have similar problems. This is a normal state that the structure must correspond to.
In Honda's recall plan, it is also clear that the ECU is adjusted to accelerate the engine's warm-up time to ensure that the engine can enter the warm-up period faster under ultra-high frequency short-distance cold engine conditions. state.
Toyota is proud of its hybrid system, which is matched with an internal combustion engine powered by an Atkinson cycle naturally aspirated engine using a dual-injection system. From the perspective of the principle of engine operation, the trend of increasing oil volume is not as obvious as that of Honda's direct injection engine.
There is also a unique technical response to the "wet wall phenomenon". Toyota's dual injection system is to solve the shortcomings of direct injection technology in poor mixture under cold engine conditions. Under cold engine, low load and low temperature conditions, Toyota's dual injection system will use intake manifold injection to provide the engine with a rich mixture, and when the vehicle is under high load conditions, the direct injection system will work.
Written at the end:
Not all problems with increased engine oil are caused by CR-V. The two engines are fundamentally different in technology, and Toyota hybrid car owners also Don't be overly nervous. The increase in engine oil in the Toyota hybrid system is simply caused by the engine operating conditions being placed in ultra-high frequency cold operating conditions for a long time. It is actually not difficult to solve this problem. Just drive on the highway for two laps and a small increase in engine oil will not cause any substantial problems.
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.