Engine, engine oil, weather and ultra-short distance driving: Who should be responsible for the increase and emulsification of engine oil?

Since the end of February, news about the emulsification of Toyota engine oil has been continuously fermented on the Internet and social media. The users involved are concentrated in Northeast China, South China and other regions.

There are different opinions on the internet about the reasons for the increase and emulsification of engine oil. After many verifications and interviews. Tian Tian Automobile has roughly figured out three possibilities behind this incident:

1, the first possibility is insufficient fuel combustion, especially in cold winter. When the vehicle starts, Toyota's hybrid engine does not work, but is driven by an electric motor. At low temperature, the temperature of the engine cylinder is also in a low temperature state. In order to warm up as soon as possible, the ECU computer will increase the fuel injection quantity to make the oil-gas mixture reach the ideal normal value. Because of this, excessive fuel will adhere to the cylinder wall due to low temperature, forming a "wet wall" phenomenon, and finally flow into the crankcase, leading to intensified oil emulsification.

2. The second possibility is that the tension of piston ring is too small. In order to save fuel consumption as much as possible, reducing piston ring or piston ring tension is one way, but this way will reduce the degree of scraping oil film on the cylinder wall, which will lead to an increase in oil emulsification.

3. The third possibility is the evaporation of oil pan caused by low temperature. Engine oil plays the role of lubricating and controlling the temperature of the engine block and circulates inside the engine. The working temperature and pressure of oil are higher, and it will expand. Under normal circumstances, the circulating engine oil will be heat-treated through the evaporation box, but due to the low-temperature driving environment, the engine oil can not be heat-treated normally, and there will be moisture. When moisture and expanded engine oil flow back to the crankcase, it will lead to the increase and emulsification of engine oil.

The outside world is the most controversial, and the owner is most worried about the first situation-in the process of low-temperature cold start, a very small amount of incompletely burned gasoline seeps into the engine oil through the gap between the piston ring and the cylinder block, which leads to intensified emulsification.

Which of the above situations does Toyota belong to? At present, there is no unified statement.

Engine upgrades may not be the culprit.

According to the survey, the increase of engine oil in Toyota models and emulsifying phenomenon mostly occur in new hybrid vehicles. These problematic models are also from TNGA (Toyota? Half-breed? System) II hybrid power system.

Equipped with Toyota second generation THS? The model of II hybrid system has been sold in China for more than two years. Why did it appear until now? What caused this problem? Is the price increase of Honda engine oil a problem in the past?

Three years ago, due to Honda's excessive pursuit of the dynamic performance of 1.5T engine, the in-cylinder injection pressure was too high, which led to some unburned fuel being forcibly sent into the crankcase during the piston compression stroke, and the oil was stored in the crankcase, which led to the repeated increase of oil. Honda oil price rises in China.

At that time, Honda's solution to the problem of oil increase and emulsification was to reduce the boost value of turbocharger, upgrade ECU program, adjust fuel injection timing and ignition timing, and speed up engine heating efficiency to reduce or even completely eliminate oil increase and emulsification deterioration.

This time, Toyota added engine oil and emulsifying phenomenon, focusing on hybrid vehicles. The twin-engine hybrid model is equipped with a naturally aspirated engine, which does not directly have the purpose of over-squeezing power performance, so there is no direct correlation between the two.

The increase of emulsification deterioration of engine oil is actually caused by two different and immiscible liquids, which have been muddied by external forces for a long time. The emulsification reason of engine oil must be engine oil and water.

At present, in addition to first-tier cities such as Beijing, many provinces and cities are using ethanol gasoline. When the engine is on standby for a long time, ethanol gasoline will be separated from engine oil. When the engine is running, water will turn into steam due to high temperature, and some of the steam will "run into" the crankcase and mix with the engine oil. Repeatedly, it increases the potential risk of increasing oil emulsification.

So what kind of environment will this risk happen?

Is the weather and squatting at home the trigger of the oil incident?

At first, most of the vehicles with problems were concentrated in the cold northern areas in winter. Because it is cold in winter, after the last shutdown, due to the temperature difference between day and night, condensed water will appear at the water inlet. Stop for another night. When the vehicle starts cold again, water is atomized through the air filter element, and the oil-gas mixture formed by mixing water and fuel will remain on the cold cylinder wall, condense with water to form an oil film, and then be scraped into the crankcase by the piston ring. Repeatedly, oil emulsification can be formed.

Oil emulsification in the north can be explained in this way, but later there was feedback from users in southern areas such as Hunan, as well as the increase and emulsification of oil. Why is this?

The reason is also very simple. Due to climate change, in recent years, rain and snow days have increased in many areas in the south, and the humidity and cold have caused the temperature to be colder than that in many areas in the north. Remember the large-scale rain, snow and freezing disaster in the south? Therefore, in the wet and cold rain and snow weather in the south, the probability of condensation in the cylinder due to insufficient cold start combustion is greater than that in the north.

At present, according to a general view of professionals, there is a risk of emulsification when the engine is in standby for a long time. The main reason is the sudden outbreak of the COVID-19 epidemic in the Spring Festival of 2020, which completely changed the normal life rhythm of all people, and dwelling in humble abode became the norm.

The number of self-driving trips is greatly reduced, and vehicles are either parked for a long time or only driven for a short time (such as supermarket procurement). This will easily lead to the engine itself and its surrounding indicators can not reach the normal and reasonable working indicators, such as water temperature, oil temperature, air-fuel ratio, transmission oil temperature and so on.

For an intuitive example, is it necessary to preheat the vehicle in place during cold start? I believe that many people's answers are yes, but they are not. Just wait until the engine speed drops after starting, then go straight to the road and drive slowly first, and then you can drive normally when the water temperature rises to the normal working temperature range. What is the significance of this time?

The most important point is that the car is heated in situ for a long time, and the oil-gas mixture is too thin, which is not conducive to warming up, and at the same time, it will increase pollutant emissions and easily form carbon deposits. Therefore, sudden start-up after parking for a long time, coupled with the short-distance driving environment during the epidemic period, will make the engine oil frequently alternate between hot and cold, accelerate the frequent gasification and liquefaction of water vapor in the engine oil, and lead to the occurrence and aggravation of engine oil emulsification and deterioration.

As the owner of Toyota, it is necessary to understand the working mode of this system. When the vehicle is started, the naturally aspirated engine does not participate in the driving, and only the motor provides the driving force. Even if the Atkinson cycle engine 4 1% has higher thermal efficiency and the water temperature rises faster, the engine does not work, and the driving conditions do not allow enough time for the engine to warm up.

Coupled with frequent low-temperature start-up and stop, even before reaching the destination, these are the incentives to increase oil emulsification. Therefore, putting an end to this short-distance and short-time driving is the only solution to effectively avoid the problem of intensified oil emulsification.

Therefore, you should drive frequently and try to avoid short-distance driving in winter.

4S stores should cooperate to change oil.

Does the emulsification of white oil at the filler cap mean that the oil is really emulsified? The daily confirmation method is to confirm with the dipstick and pull out the dipstick. If the oil stuck on the dipstick is milky white, it means that the oil has been emulsified and deteriorated. Go to the 4S shop for replacement as soon as possible, and the 4S shop should also actively cooperate with the oil change. If not, it proves that the oil is not emulsified.

There is a large amount of emulsion on the oil filler cap. Why? The reason is that when the engine stops, the ventilation and cooling system is also closed, but the heat of the engine will naturally rise, and it will condense into water droplets when it meets the cold air above. After a long time, it will react with the oil residue and oil-gas mixture attached to the cover to form oil emulsification, which is actually a normal phenomenon.

Can hybrid electric vehicles compare with pure electric vehicles?

With the development of automobile technology and technology, the degree of automobile electronic control is getting higher and higher, but ordinary consumers can't match it in driving technology, way and understanding and application of automobile common sense, so there will be vehicle failures caused by improper driving operation, such as turbocharger damage of Volkswagen models at that time.

That is to say, in view of China's car environment and driving mode, the research and development and breakthrough of new car technologies are, to a great extent, gradually adapting to and improving consumers' car habits and minimizing the damage to parts caused by improper human operation.

Toyota's research and development and evolution of hybrid power technology for decades are leading, mature and reliable all over the world. The appearance of this problem actually provides a realistic blueprint for Toyota manufacturers to update their products in the future and eliminate such problems.

As one of the technical routes for diversified development of power in the future, Toyota's global sales of hybrid technology vehicles have reached nearly10 million, which is the most energy-saving vehicle in the world at present. Compared with the problems of charging and spontaneous combustion commonly faced by pure electric vehicles, the increase of oil emulsification is not a technical fatal injury.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.