In your mind, diesel engines all belch black smoke and make a lot of noise, used either in tractors or in heavy trucks, right? But anyone who has been to Europe knows that their cars all use diesel engines and run like a charm! Why is the treatment so different?
Wherein lies the “marvel”?
The biggest advantage of a diesel engine is thermal efficiency—to put it more simply, it is very fuel-efficient. A diesel engine of the same displacement consumes only 60%–70% of the fuel of a gasoline engine; even with hybrid technology, a gasoline engine cannot match it. A pickup truck weighing over two tons can actually achieve fuel consumption at the level of a B-segment sedan—truly hard to imagine.
Another advantage of the diesel engine is its very strong low-end torque: it can reach maximum torque at a relatively low engine speed range. Of course, torque at high engine speeds also drops off quickly, but most people's daily driving habits do not exceed 3,000 rpm anyway.
Emissions remain a point of discussion
Emissions are the biggest issue for which it is questioned—after all, not long ago Volkswagen's “emissionsgate” triggered a major public debate. In fact, with the application of high-pressure common-rail technology and advanced exhaust after-treatment technology, diesel vehicles have long ceased to emit black smoke, and their widespread use in Europe, where emission regulations are so strict, is enough to prove their environmental friendliness.
But the domestic vehicle-use environment dooms it to be unable to deliver the best emission results. First, the quality of domestic diesel fuel has always been uneven—can you still expect the exhaust after combustion to meet standards? Second, advanced diesel exhaust after-treatment technology currently still relies on automotive urea for treatment. Many people probably do not even know what automotive urea is, let alone buy it and add it.
What is blocking its path to development?
Some say that domestic diesel consumption is large—heavy trucks, ships, and industry all need it—so passenger cars should not get involved and compete for the fuel. In fact, since there is market demand, sufficient diesel can certainly be supplied, but the premise is that it can make money.
A very realistic factor is that diesel earns less than gasoline—gasoline profits are much higher than diesel. So a couple of years ago, because diesel did not make much money, refineries were unwilling to produce it, which led to the phenomenon of trucks queuing up to fill diesel. However, after a series of policy adjustments, diesel is no longer scarce and can fully meet supply.
The reason passenger-car diesel engines have not taken off is that the government does not advocate them. Because diesel is still a fossil fuel energy source, it is not worth continuing to promote. Moreover, they believe that pure electric vehicles have broader development prospects and are more environmentally friendly (although at present their environmental friendliness remains controversial).
It is not only in China that they are regarded as junk
To be honest, the United States is also one of the countries where diesel engines are not taken seriously—after all, their fuel prices are cheaper, and they prefer large-displacement gasoline engines rather than diesel engines. The popularity of diesel engines in Europe may simply be a geographical advantage.
