Multi-section cylinder MA
Its power arrangement is very interesting. The left and right wheels of the rear axle are respectively equipped with a motor, which can be driven independently. The three-cylinder engine is arranged near (in the middle of) the rear axle, but it is used to drive the front wheels. A motor (which can be understood as ISG) is also connected in series on the engine crankshaft. This power arrangement is more attractive to popularize, because the horsepower of the three motors plus the engine exceeds 1700ps, and the battery power is sufficient, so it is the king of the straight line on this road. If there is no power, the official will not comment!
Why use three cylinders? Because the people sitting in the back row are human! Speaking of which, I suddenly thought of another car, that is BMW i8. As the originator of a three-cylinder sports car, the i8 may be the only car with a three-cylinder engine but no spray.
I think it is difficult for many people to understand why such an expensive sports car needs three cylinders. Maybe we can find some answers from the design of BMW i8.
The road to electrification?
Koenigsegg Gamela? Similar to BMW i8, both of them want to build an efficient car, which is divided into two aspects, one is driving efficiency and the other is regeneration efficiency. So they all use motors to drive the front and rear axles respectively. Because there are engines and motors in the power system, it is equivalent to new energy.
The driving structure of new energy can be roughly divided into three categories (see the above figure), in which A stands for series electric vehicle (BMW i3), B stands for parallel electric vehicle (530le) and C stands for parallel electric vehicle (X6 hybrid of the first generation BMW). Strictly speaking, D is not a hybrid structure, but a four-wheel drive structure, which is called split-axis four-wheel drive in the industry, such as BMW i8.
New energy has an arithmetic problem, that is, the ratio of electric power to mechanical power. Electric power refers to driving motor power, and mechanical power refers to engine power. If you blindly pursue speed, it must be high electric power. If you pay attention to efficiency, it is high mechanical power. Obviously, BMW i8 chose efficiency.
The advantages of split-axis drive mode are obvious. The engine only needs one bridge, which saves the transfer case, central differential and transmission shaft, and the motor does not need to be dragged down by the engine, so the braking energy can be fully recovered when braking, killing two birds with one stone. If we follow the idea of efficiency, we will find that multi-cylinder and large-displacement engines seem to be of little use. To ensure the power, we only need to increase the motor power and maintain the battery life, and only need a small engine.
With small and broad?
Everyone knows that hybrid power is the transition scheme of pure electric vehicles. What's the use of a large-displacement engine if we want to design a hybrid that pursues high efficiency? This question is a little puzzling. Let's just say that a large number of cylinders means a large volume and a large weight. Although it can provide relatively large power, it also consumes a lot of energy to maintain power.
How can we balance power consumption and energy consumption? The idea in Europe is to shrink the cylinder. On the one hand, reducing the number of cylinders will reduce the weight of the engine and improve the efficiency of friction loss. More importantly, under the same displacement, the engine with fewer cylinders has a large single cylinder volume, which means that the combustion efficiency of the engine can also be improved, and there is no need to pay displacement tax!
What kind of engine is excellent? Small size, of course. Koenigsegg, a 2.0T3-cylinder engine, has a horsepower increase of 305ps and a torque increase of 300 N m. It is meaningless to increase the volume by adding cylinders.
Didn't we say electrification? How can an ordinary car do split-axis drive like i8? In addition, the car is not necessarily a four-wheel drive. The degree of electrification is getting higher and higher, and the size of the motor is getting bigger and bigger. How can there be room for gearbox and motor in the engine room?
The current gearbox is not compact enough? It can't be any smaller, and it doesn't make much sense. High-power motor itself is not large, so it is difficult to shrink. The only thing that can shorten the size without reducing the power is the engine. Considering that the hybrid may be equipped with dual motors in the future, the compact car is equipped with a 3-cylinder engine, which can obviously lay the foundation for future electrification.
Stronger, smaller and higher power is a challenge to engine designers and also conforms to the future development trend. After all, lightweight is conducive to fuel consumption and handling. Back to the topic, strictly speaking, i8 is not a traditional sports car, but a concept product of environmental protection and energy saving. When the car develops towards electrification, the importance of the engine will gradually decrease, so the engine power is getting smaller and smaller, and the motor power is getting bigger and bigger. At this time, the rise of the three cylinders is justified!
Write it at the end
European manufacturers have clear ideas. I need an engine with high volume density and power density to ensure endurance, and the engine needs a gearbox to maintain high efficiency. However, at this stage of the transition from a fuel vehicle to an electric vehicle, both the gearbox and the motor are needed. With the motor, the engine is no longer needed to provide great power, so the three cylinders appeared.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.