Posted 2022-08-11 00:00:00 +0000 UTC
Recently, I saw a special news. In order to meet the emission policy requirements of Europe, the next generation of fox RS will cancel the existing 2.3t + 6mt powertrain and replace it with a hybrid system. It's special because we rarely hear about hybrid systems on performance bodies - even if it's not confirmed. Such as RS series, M series, Type-R, GT-R and other well-known performance car series, all use pure fuel power. As a representative model of Ford performance vehicle, fox RS is actually related to hybrid and the most complicated PHEV. Is this the rhythm of overtaking on a curve? ▲ if the next generation fox RS is equipped with hybrid system, it will become the first hybrid small steel gun in the world. In fact, a few years ago, there have been a lot of super runs driven by electromechanical combination in the market, such as laferrari, P1, 918, etc. We can see from these super runs that electric technology can not only improve the fuel economy of the car, but also significantly improve the power output of the car, which provides a simple, direct and highly efficient evolution direction for the development of performance vehicles. Of course, the performance car is different from the super run, it must retain a certain degree of practicality and fuel economy. Under this premise, in which direction will the electric road of performance vehicles go? Is it popular, or is electromechanical coupling the mainstream? Let's talk about it. Pure electric vehicle is not really suitable for performance vehicle. When pure electric vehicle was first popularized in China, there are two indicators that consumers pay most attention to and vehicle enterprises pay most attention to. One is the endurance distance and the other is the acceleration time of 0-100km / h. The former is to prove the practicability of electric vehicles, while the latter is to reflect the "high-tech" attribute. What is the "zero hundred" acceleration time in 4 or 5 seconds that any fuel vehicle can achieve? The powerful acceleration performance makes the electric vehicle catch the attention of consumers quickly and even accelerate its popularization speed. In addition, pure electric vehicles also have the advantages of low body center of gravity, no delay of accelerator (switch) and other related to vehicle motion attributes, which can not help but make people associate that the technology of electric vehicles is not the most ideal solution to the performance vehicle? It's a well-known fact that the speed of pure electric vehicle is fast, but is the fast car a performance car? (image: model s racetrack version.) But in Xiaolu's view, pure electric power system is not only not suitable for performance vehicles, but also has many significant shortcomings. First of all, we need to correct a point of view that a fast accelerating car is not equal to a performance car. For a passing performance car, linear acceleration performance is only one of the key indicators. Equally important are handling, lightweight levels, and durability under high load conditions, which must have been overlooked by the most people. Is fast acceleration a performance car? Frequent rapid acceleration and long-term high-speed / high-speed driving will keep the power system under high load condition for a long time, which is the most common driving mode for performance vehicle users. For general internal combustion engines, the cooling system and lubrication system can be upgraded, or the components with higher strength can be used to cope with high load conditions. ▲ the traditional diesel engine performance vehicle is very good at working under high load conditions. But pure electric cars are different. Even with the advanced temperature protection system, too frequent charging and discharging will affect the durability of the battery. In addition, limited by the working characteristics of the motor, the electric vehicle is not suitable for long-term high-speed driving, and the high-speed re acceleration ability is also poor, which further limits its performance as a performance vehicle. Due to the characteristics of electric motor and battery, pure electric vehicle is doomed to be unable to drive with high intensity for a long time. In addition, the weight of the electric vehicle itself is also a big limitation, the first one is the battery pack, whose weight accounts for at least 1 / 3 of the whole vehicle. Taking Tesla Model 3 as an example, it is equipped with a battery pack with a capacity of 75kwh, with an energy density of 260wh / kg, which is the top level of mass-produced electric vehicles at present. But the weight of the battery pack alone has reached 478kg. In addition to the battery shell, heat dissipation module and other components, the weight of the whole battery assembly of model 3 is about 650kg, which makes the weight of the whole vehicle exceed 1874kg. In contrast, the size of the larger version of model 3, the weight of the whole vehicle is only 1730kg. Looking at the HEV field, the size is also larger than model 3, but the weight is only 1650kg. Because of the larger battery, the weight of pure electric vehicle is much higher than that of the same type. Compared with the same level of electric vehicles, the weight of pure electric vehicles is undoubtedly the largest, and compared with the same level of fuel vehicles, the gap is more obvious. For performance vehicles, the negative impact of heavier body is obvious. Even if the acceleration ability is guaranteed, the physical indicators such as bending limit and braking distance are difficult to overcome. ▲ too heavy body is a great burden to the brake system. Due to various limitations, there is not a pure electric performance vehicle that can achieve mass production on the market. what? You mean the Porsche taycan? The car's performance is really remarkable, but in the Porsche product line, taycan's positioning is just a pure electric four door car, not a performance car. After all, a car like the 911 GT2 RS is a "Porsche performance car"! For Porsche, taycan is just a pure electric four door coupe. Although HEV has the potential to move, it still has a distance from the requirements of performance vehicles. Since the pure electric route is not feasible, how about hybrid? At present, hybrid vehicles in the market are mainly divided into three categories: light hybrid (mhev), oil electric hybrid (HEV) and plug-in hybrid (PHEV). Because the motor power of mhev is generally low, and the improvement of performance is very limited, our discussion is focused on HEV and pehv. In recent years, HEV has developed rapidly, which is mainly driven by the "two fields" strong products. However, when it comes to hybrid oil and electricity, the first thing you think about is the word "fuel saving", which is not related to performance. This is not surprising. At present, the focus of HEV publicity is on "saving, quietness and smoothness". None of the HEV models on sale takes power as the selling point, which greatly affects people's impression of HEV. However, the answer from hearsay and personal experience is quite different. Xiaolu himself is a ten generation hybrid car owner. In more than one year with this car, what I am most satisfied with is not the fuel consumption, but its performance. The ten generation Accord hybrid is equipped with a hybrid system composed of a 2.0L engine and a dual motor, with a maximum power of 158kw. The measured acceleration time of 0-100km / h is about 7.5S, which is equivalent to a 2.0T power medium-sized car. Its greater highlight lies in the electromechanical coupling mode: in the process of rapid acceleration, the vehicle will be directly driven by the motor, so it has a sensitive acceleration ability similar to the pure electric vehicle. ▲ accord's hybrid throttle is very responsive, and the power comes at a little bit, which many fuel vehicles can't do. When driving at high speed, the vehicle is directly driven and the battery is continuously charged to ensure the durability of high-speed driving. In addition, after adding the motor and battery, the overall weight of accord hybrid is only 100kg more than that of the fuel version, which shows that its lightweight level is quite excellent, and through the reasonable layout of the battery, it can effectively balance the front and rear weight of the car body. ▲ Honda i-mmd hybrid system also has its own performance. Since accord hybrid retains the characteristics of pure electric, it solves the inherent shortcomings of pure electric part and achieves the balance of performance and practicability. So I've been thinking that if i-mmd system of accord hybrid is put on a model with smaller weight and higher frame strength, can't its performance be further developed? However, the fact tells me that there are still some shortcomings in this kind of hybrid system, which is mainly in series mode. ▲ in Honda i-mmd hybrid system, the engine is only a "supporting role". Due to the motor driving in the acceleration process, in the high-speed re acceleration process, there will still be the problem of weakening the acceleration performance due to the decrease of motor torque. Even if the charging efficiency of the engine is higher, or the battery capacity is larger, it is difficult to fundamentally change the characteristics of the motor. It can be seen from the working characteristic diagram of permanent magnet synchronous motor that the maximum torque can be output at the speed of 0, but when the speed exceeds a certain speed, the torque change will decline with the increase of speed, and the power will be kept at a constant level. Because the performance vehicle must meet the two major characteristics of power output and durability at the same time, fuel saving and ride comfort are secondary. Therefore, to build a truly applicable electric power system for performance vehicle, the motor cannot be the main role, and the engine must participate in driving the vehicle to the maximum extent. Is the th hybrid system OK? In the Toyota ths system, the main power source is one engine and two motors. In theory, the combination of engine and motor can produce powerful power, but in order to make the whole system play a higher energy efficiency, Toyota uses a set of planetary gear set as the power distribution mechanism to adjust the torque output in real time during the driving process. The core of Toyota hybrid system is to distribute the power output of motor and engine through planetary gear set, so as to achieve the most ideal working condition. Its design is not intended to extract performance. Because the power is divided, the power of the engine can not be fully output to the wheel, a considerable part of it is divided to the motor system. Both the engine and the motor are operating around the goal of high efficiency and low energy consumption, rather than blindly pursuing the power output, which is why the ths system has excellent energy consumption performance, but the power performance is not outstanding. On the body, when we see the prospect of electric performance vehicles excluding pure electric and "two fields" hybrid system, we must think of another iconic power system, BYD DM dual-mode system. Remember BYD's 542 strategy? "5-second acceleration, 4-wheel full-time electric drive, fuel consumption within 2 liters per hundred kilometers", the first "5" is aimed at improving performance. When BYD proposed the "542" strategy, it took improving performance as its main goal. At present, BYD's DM system has developed to the third generation. Taking the current BYD Tang DM as an example, it adopts the original P0 + P3 + P4 hybrid configuration, in which the motor at position P0 is mainly used to assist the engine power output under low speed and low load conditions; the P3 motor is located at the output end of the gearbox, with a power reserve of 290Kw and 630nm, which can realize parallel connection with the engine and output strong power; while the P4 motor is independent of the engine on the rear axle, except that Besides the auxiliary power output, pure electric four-wheel drive is also realized. It is worth noting that when the engine is fully output, its power can be fully released to the wheel, without going through the complex electromechanical coupling system, under the coordinated output of the motor, it can achieve the efficient superposition of power. Although such a design is not conducive to reducing energy consumption, it can meet the demand of power to the maximum extent, but also ensure the stability of performance under high-speed and high load conditions. ▲ the handling performance of BYD Tang DM is not excellent, but its unique hybrid system has reference value. On the other hand, the motor located at the rear axle of the Tang DM also has great achievements, although its power output is not as good as that of the front axle motor（
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