BYD DM-i is full of advantages, isn't there any disadvantage?

Once BYD's DM-i super hybrid system was released, it caused an uproar in the automobile circle. BYD, which is no longer obsessed with performance, has achieved the ultimate fuel consumption this time: among them, Qinjia DM-i claims that the fuel consumption per 100 kilometers can reach 3.8L at 25% low power. At the same time, the acceleration score of 100 kilometers can reach 7.3S Among SUV models, the fuel consumption of Songjia DM-i can reach 4.4L and that of medium-sized SUV Tang DM-i can reach 5.5L.

In the past, when we talked about fuel economy, the first thing that came to mind was Japanese cars, which saved fuel, but the power was more fleshy, which has always been recognized by everyone. For example, Toyota Corolla dual-engine version, the power is solid, the acceleration of 100 kilometers is nearly 12 seconds, and it is ok to drive in the urban area every day. If you really want to overtake on the national highway, it's really a bit overwhelming. However, the fuel consumption of Corolla is really low. The measured average of 1.2T is about 6.7L, while the fuel consumption of the dual-engine version of the Ministry of Industry and Information Technology can reach 4. 1L, and the measured fuel consumption is also about 5.4L The performance has been excellent.

But ... the hybrid of oil and electricity, coupled with the sacrifice of power, only achieved 5.4L, and Qin Plus, which claims to accelerate within 8 seconds of 100 kilometers, can really achieve fuel consumption below 4L? Is it a virtual standard? Are you bragging?

Shortly after the press conference, BYD invited the media to test drive the real car. The fuel consumption of 3.8L is really just a conservative figure. In the actual measurement, the average fuel consumption is much lower than 3.8L, and the lowest is even less than 3L! What is this concept? Even if this car is never recharged, it will cost more than ten yuan to drive as a pure fuel car! Almost comparable to a pure tram! And there will definitely be no problem of endurance anxiety!

How did it do it?

In fact, it is not the DM-i system that saves fuel, but our traditional fuel vehicles consume too much fuel!

Internal combustion engine is not advanced. Since the invention of 100 years ago, the principle has not changed. Everyone should understand its basic principle: in short, it is to inhale and inject oil, then ignite the oil-gas mixture in the cylinder, push the piston to do work, then exhaust and inhale, and so on.

But this thing is not as perfect as we thought. First of all, we can't synchronize the engine speed with the vehicle speed. When the engine rotates slowly, the speed is slow, and when it rotates fast, the speed is fast-this is impossible, because the engine rotates too slowly, and the vehicle can't move at all! (insufficient low torque)

In order to solve this problem, we must amplify the torque of the engine through gears. Simply put, there is a pinion on the engine side and a big gear on the wheel side. The wheel turned up and down several times before it moved down. In fact, it is a very simple lever principle. Finally, the car moved.

However, the higher the engine speed, the more fuel injection times and the more fuel consumed naturally. In addition, the number of engine revolutions cannot be increased indefinitely. On our dashboard, more than 6000 rpm basically enters the red line area. However, using such a pinion to drive a vehicle, even if the engine has the highest number of revolutions, the speed is only 40Km, which means that the car is not fast.

Therefore, engineers can add several groups of gears, that is, the gears of the gearbox. The essence is to change the transmission ratio to improve the speed. At the beginning, the pinion was used on the engine power output shaft, and the big gear was connected to the wheel. But at high speed, with inertia, you don't need so much "strength". The gear on the output shaft is larger and the gear on the wheel is smaller. It used to be a 30-turn wheel here, but now the speed will rise in 5 turns here.

To put it bluntly, the gearbox is the crutch of the engine. The engine is born with two legs. The torsion of one leg and one foot is not enough, and the rotation speed of one leg and one foot should not be too high. A single engine can't drive the vehicle, so it can only run with crutches.

At first, it was manual control. Later, automatic gearbox, CVT and dual clutch were invented, which was too much trouble. However, after all, it is a crutch, and it has to be lifted, just like stepping on a clutch to interrupt power. Double clutch is a crutch, which can shift gears quickly, but sometimes it is easy to mix garlic and bump. Even if the AT gearbox is comparable to the wheelchair level, it still cannot change the fact that the engine is congenitally deficient.

The engine is running forward, but the performance is still not satisfactory. Just because there is no competitor, the problem is not prominent (the competitor of early cars is the carriage). We are used to the fuel consumption of 100 km 10L, 8L, which looks natural. However, in fact, there is a lot of waste when the car is driving.

1, Start-up stage: Due to the inherent defects of internal combustion engine and insufficient low torque, in order to provide enough torque, the speed has to be increased in the start-up stage, resulting in increased fuel consumption. For example, the current 48V light mixing technology can really save fuel, and the principle is nothing more than assisting to provide torque in the initial stage. To put it bluntly, the engine consumes too much oil when it starts, so the motor helps push it.

2, parking idle speed: In order to maintain the power of the vehicle, when waiting for the red light, most vehicles will idle, the engine will run at low speed, and at the same time charge the battery in the car. In order to solve this problem, some car companies have created an automatic start-stop function full of anger and resentment. Can you save fuel? It is possible in theory, but the actual experience is very poor.

3. Low-speed driving: If you want to keep driving at a low speed, the low torque of the engine is insufficient, and you can't turn the number of revolutions to a very low level. Even if the speed is only 5Km/h, the engine should work at the speed above 1000 rpm, with low output power, insufficient fuel combustion and great waste.

4. High speed: Generally, the maximum horsepower of an engine corresponds to high speed. If you want to explode strong power, you must increase the engine speed. However, high speed means high fuel consumption. Many times, when the floor oil goes down, the fuel tank is a small whirlpool. Like fuel-efficient Japanese cars, it is often at the expense of power.

5. Power loss: When we slow down and step on the brakes, we can only offset the kinetic energy of the vehicle by rubbing the brake pads, and this part of energy is also wasted.

Not only the low energy conversion efficiency, the vibration and noise generated during operation, but also the carbon deposition and wear caused by long-term use are all headaches. In short, the engine is actually such a defective thing. It has only one advantage, that is, it is convenient to refuel.

Why can BYD's DM-i model achieve such low fuel consumption? Actually the principle is not complicated. The first is super high thermal efficiency, and 43% of the engine thermal efficiency ranks first in the production car. Secondly, it uses electricity to make up for the uneconomical working condition of the engine. As long as the engine is started, it is the best working range of 43% thermal efficiency. If the speed allows, the vehicle can be directly driven to avoid waste in the process of energy conversion. If it is crawling at a low speed, charge it with a battery with 43% thermal efficiency, and then drive the vehicle with electricity.

You know, the conversion efficiency of electric energy is much higher than that of internal combustion engine, which can basically reach about 95%. Moreover, there is no problem of insufficient low torque, smooth power, fast throttle response and no noise and vibration of the engine.

Electricity is used initially, and there is no idle speed when parking. When crawling at low speed, if there is enough electricity, it will be driven directly in the form of pure electricity. If the power is insufficient, the extended range mode will be enabled, so that the engine can charge the battery with 43% thermal efficiency and drive the vehicle with electricity. If you drive 50Km in the urban area, the engine may only be working for about 20-30Km, and the rest of the time is zero fuel consumption.

That's why I said, in fact, it's not that DM-i saves fuel, but that traditional fuel vehicles consume too much fuel! BYD claims that this DM-i is a blow to traditional fuel vehicles, and I deeply agree with it. It's time for the engine and gearbox of traditional fuel vehicles to quit the historical stage. They have been in service for hundreds of years, and we have managed to use them for more than 100 years.

We endure high fuel consumption, high emissions and high pollution. We tolerate the weak power of small displacement and the sluggish throttle response speed. In order to solve the problem of smooth power, we have improved the gearbox many times and adjusted the NVH of the vehicle again and again, which solved the noise problem. But that's the truth. Many cars still inevitably produce vibration and abnormal noise after several years of use. ...

Backward engines and gearboxes are not terrible. What is really terrible is our backward thinking. We eliminated the carriage with the internal combustion engine, and were complacent for hundreds of years, not enterprising!

Now, plug-in hybrid is coming. In front of DM-i, fuel vehicles have no advantage, and both power and fuel consumption are crushed to the ground.

There are still many people who think that our automobile industry is still backward and that our domestic cars are not as good as those in Europe, America, Germany, Japan and South Korea. They don't deny progress, but they still feel there is a gap-where is the gap? Over the years, international traditional car companies have said that it is no exaggeration to sit on the achievements of predecessors! Even many people don't realize how backward the power combination of engine and gearbox is! Now BYD is overtaking in the corner, Qin Jia DM-i can achieve fuel consumption below, and the acceleration of 100 kilometers is still within 8 s. Who else? Han DM accelerates 4.7S seconds per 100 kilometers, but the fuel consumption is only about 6L. Are there any competitors at the same price?

Many people still can't turn the corner, and they always feel that it is unfair to compare new energy sources with fuel vehicles-what is unfair? Plug-in hybrid kinetic energy can do everything a fuel car can do, and it is more powerful than you, with lower fuel consumption and smoother and more comfortable than you. Now plug-in hybrid can completely replace fuel vehicles, which is called: dimension reduction!