Great Wall Motor Slogan

On March 10, 2003, Great Wall Motor released a new generation of hybrid technology-HI4.

This technology is very different from the existing hybrid vehicles in structure. It can realize the electric four-wheel drive of new energy vehicles at a small cost, so that consumers can buy four-wheel drive with the money of two-wheel drive, making it possible to popularize electric four-wheel drive vehicles.

Great Wall Motor even directly shouted such a slogan: "Bring China Automobile into the era of all-people electric four-wheel drive."

National electric four-wheel drive? The implication is not to "kill" the two-wheel drive and let it become history?

What a big breath!

I believe you have raised many questions at this moment, such as: What is the difference between the Great Wall Hi4 and other hybrid technologies? How is its low-cost electric four-wheel drive realized? Which cars will be equipped with Hi4? How much does it cost?

Don't worry, let's analyze it bit by bit.

Basic structure of hybrid electric vehicle

Broadly speaking, a car that can burn oil and use electricity can be called a "hybrid car"? . However, how to achieve this goal, different manufacturers often have different solutions.

For example, the different positions of the motor will have a great influence on the structure and effect of the hybrid power system.

According to the position of the motor, the motor can be divided into P0~P4 and other layouts. The following figure can well reflect the differences of motors between different layouts.

P0 motor: located at the belt end of the engine, driven by the belt, with low power and torque, mainly responsible for engine starting assistance and power generation. In the auxiliary drive, the power is transmitted through the belt, which has limited effect;

P 1 motor: located at the flywheel end of the engine, in front of the clutch and directly driven by the crankshaft of the engine. Its power is larger than P0 motor but limited, and its function is basically the same as P0 motor. However, in assisted driving, the power is transmitted through the crankshaft, and its function is greater than that of P0 motor.

P2 engine: It is located behind the clutch and in front of the transmission, not in the same housing as the engine, so it is larger in size and higher in power. At the same time, because there is a clutch between it and the engine, it can drive the wheels independently without driving the crankshaft of the engine, thus making pure electric drive possible. However, because power is also transmitted through the transmission, there are still some losses in power transmission;

P3 motor: Located behind the transmission, it has more layout space, so the power can be further improved. At the same time, the power output can directly drive the wheels without the transmission, which is more efficient when driven by pure electricity, so it is mainly used to drive the motor and is not responsible for power generation and other work;

P4 engine: It is not on the same axis with the engine, usually located at the rear axle, and has no power connection with the engine, but is connected with the front axle through the ground. P4 motor is generally used to supplement the power of performance cars, and electric four-wheel drive can also be realized through the front axle.

It is not difficult to see that P0~P4 cars have their own characteristics. The difference of hybrid technology between different manufacturers can also be simply regarded as the combination of different motors.

For example, BYD's DM-i is a hybrid system of P 1+P3 motor. Among them, P 1 motor is mainly used for power generation, and P3 motor is mainly responsible for driving wheels. There is a clutch between the engine and the output shaft, through which the output of the engine can be disconnected or connected, and the pure electric/parallel/direct drive mode can be switched.

Image source: Zhihu Net Yuan Qi

The advantages of this system are obvious: no gearbox, simple structure and low cost. At low speed, the clutch can make the engine only drive the P 1 motor to generate electricity, and keep it in the best efficiency range for a long time, and then drive the wheels through the P3 motor, thus realizing the extended-range series hybrid power. At high speed, the engine can be driven directly to reduce the loss caused by kinetic energy transfer, or it can be driven in parallel with P3 motor to bring better power.

It can be seen that the biggest advantage of the system is energy saving, but it also has disadvantages: because there is no gearbox, the engine and P3 motor use a reducer, and the engine works in single gear when it is directly driven and parallel, so the DM-i engine can only be directly driven or parallel driven when it reaches a certain speed (official data is between 60-70km/h).

This makes the power of DM-i engine can not be fully utilized at low and medium speeds, and the vehicle power performance is average. At the same time, because the whole power system is on the front axle, it is difficult to realize electric four-wheel drive.

To this end, BYD subsequently introduced MD-p, adopting the structure of P0+P3+P4:

Due to the addition of high-power P4 motor on the rear axle, the performance of the vehicle is improved in the form of dual motors, and electric four-wheel drive is realized at the same time, but the cost and price are also greatly increased.

Back to the Great Wall. Their "lemon hybrid" also adopts the layout of P 1+P3, which also supports series-parallel hybrid power, but after the clutch, a two-speed transmission dedicated to hybrid power is added, which is what we often call "DHT".

Image source: Zhihu Net Yuan Qi

It is precisely because of the addition of this two-speed DHT that lemon hybrid can realize two-speed direct drive/parallel connection, so that the engine can intervene in parallel mode in time at medium and low speeds (the official data is about 40km/h), which significantly improves the power performance of the vehicle at medium and low speeds.

However, this still can't solve the problem that P 1+P3 layout is difficult to realize four-wheel drive, so Great Wall Motor introduced a special hybrid configuration for four-wheel drive-HI4.

What's the difference between Hi4 and other hybrids?

Different from the existing hybrid system, the Great Wall Hi4 adopts a hybrid configuration of P2+P4, that is, the front axle motor is located behind the clutch and in front of the transmission; The former P3 drive motor has now been transferred to the rear axle to become P4 motor.

The unique motor layout makes this Hi4 have the following features:

1: The front axle motor can directly drive the wheels without driving the engine crankshaft, so the loss is small;

2. The power output of the front axle motor also passes through the 2-speed gearbox, which can realize high torque/high speed switching;

3. Through the clutch, the engine can also realize direct drive, and at the same time, the two-speed DHT can realize medium and low speed intervention and parallel connection;

4. Through the clutch, the engine drives the front axle motor to generate electricity, and the rear axle motor is driven independently to realize series (extended range) pure electric rear drive;

5. The front and rear motors work at the same time, which can realize pure electric four-wheel drive; After the engine is started, four-wheel drive can be connected in parallel to realize the full release of system power.

It is not difficult to see that the biggest highlight of the P2+P4 configuration of Hi4 is the realization of four-wheel drive without increasing the number of motors, which makes the overall cost controllable and makes the popularization of four-wheel drive technology possible.

Some people may ask: What's so good about four-wheel drive? Why did you join?

As we know, four-wheel drive makes all four wheels of the car have power, which brings better control and passability to the vehicle. However, due to the single power source (engine), traditional fuel vehicles often need complex mechanical transmission structure to realize four-wheel drive, which will greatly increase the cost, so only some models can carry it.

After the electric drive of the car, the power source becomes a motor, and only two motors are needed to easily realize the electric four-wheel drive of the car.

At the same time, the electric four-wheel drive of Hi4 is different from the traditional four-wheel drive, because it does not depend on mechanical transmission, so the power (torque) output of the front and rear axles can be flexibly adjusted, further improving the handling and passability of the car.

The existence of electric four-wheel drive can also make the power output not limited to a certain axle, realize better performance release based on the grip of four wheels, and reduce the slip caused by excessive torque and power.

In addition, the motor also has an "optimal working range" in energy recovery, and energy recovery may break through this range at high speed, resulting in energy waste. Hi4 makes full use of the dual-shaft motor in energy recovery, which can realize dual-shaft energy recovery/single-shaft energy recovery, and the energy recovery efficiency is higher, which is reflected in the longer cruising range.

In this regard, I just want to say that four-wheel drive will become one of the core advantages of automobile electric drive.

However, the P2+P4 configuration of Hi4 also faces many difficulties. The first thing is the arrangement of P2 Automobile Company.

The space between the clutch and the transmission is limited. Put a traditional motor here, you can only choose between volume and power. Great Wall Hi4 technology directly integrates P2 motor and electronic control into DHT transmission to form a set of "DHT electric drive assembly".

This set of "DHT electric drive assembly" is closely combined with the engine through the gear structure, which not only saves the axial space, but also further reduces the manufacturing cost, and becomes the key to Hi4 low-cost four-wheel drive.

On the other hand, in order to achieve high power in a limited volume, the motor of Hi4 also adopts technologies such as flat wire winding with hairpins, variable lubrication flow control, low-resistance and high-efficiency bearings, so that the maximum efficiency of its motor reaches 94.3% and the maximum power reaches 80kW (there is another 70kW low-power version).

Which cars will be equipped with Hi4 hybrid? how much is it?

According to the press conference, the first model equipped with Hi4 hybrid will be a new car of Harvard, which was officially unveiled at the end of March. According to Harvard's previous pricing strategy and Hi4 hybrid's technical positioning aimed at "popularizing technology", there is no doubt that it will target the most mainstream market. After all, the great wall's rhetoric has been released: "the price and energy consumption of two-wheel drive, the performance and experience of four-wheel drive", perhaps we can look forward to it in terms of price.

In addition, according to the media communication meeting before the press conference, the Hi4 will have two powertrains:

Low profile: 1.5L engine +70kW gearbox+150kW rear axle motor;

Equipped with: 1.5T engine +80kW gearbox+150kW rear axle motor.

At the same time, the battery pack will have two capacity specifications:/kloc-0 19.94kwh/27.5kwh The pure battery life of the whole vehicle can reach 100+km, and the system power range can reach 220kW~350kW, covering A/B/C level.

It is foreseeable that not only Haval, but also Hi4 hybrid will be applied in more brands. As the mainstay of the Great Wall brand, Harvard is indeed the most likely sales platform to realize the rapid popularization of technology.

When the whole market is engaged in price war by reducing distribution and cost, Great Wall Motor increases products through technology, hoping to seize the market through the leap of product strength. This is undoubtedly a risky move, but it also shows the determination of Great Wall Motor.

From a technical point of view, the advantages of Hi4 are obvious. Many characteristics of electric four-wheel drive significantly improve the handling, passability and safety of vehicles. More importantly, the cost of this system is not much different from the existing two-wheel drive lemon mixing, and the price of the final product will be basically the same.

But in the market, there is still a question, that is, between price reduction and electric four-wheel drive, how will consumers choose?

The market will tell us the answer.

This article is from Che Yi and Shi Zhi, and the copyright belongs to the author. Please contact the author for any form of reprint. The content only represents the author's point of view and has nothing to do with the car reform.