Text/Civil
Compared with the series hybrid structure, the complexity of the parallel hybrid structure has been improved. The simple understanding is that the parallel hybrid system integrates the fuel power system with the electric drive force system to form a parallel line, allowing the car to drive the engine and motor together or drive separately.
The parallel hybrid structure can be understood as a mechanical connection between the engine and the electric motor. The parallel hybrid system is basically to add a set of motors and high-voltage battery systems inside the traditional fuel vehicle, and the position of the motor is generally placed in the position of P2, and a few are placed in the P3 position (P2: located in the middle of the engine and the gearbox on the side of the gearbox, and there is a clutch between the engine, P3: located behind the gearbox).
Parallel hybrid systems work in a similar way to series, but in a different way, let's take the more common P2 parallel as an example:
1, in the case of low-speed driving, if the battery is sufficient, then through the motor to drive the car alone, the engine does not work, the economy is higher.
2. When the power required for driving reaches the power generated by the efficient working range of the engine, the engine drives the car alone, and the motor does not work, and the benefit is better.
3. When a large power output is required, the engine will be driven together with the motor. First keep the engine in the most efficient operating range, and then gradually increase the output of the motor. If the power output is still insufficient at this time, the gearbox will intervene to downshift to increase the speed and output.
4. When the vehicle form is in more complex road conditions, the engine efficiency is constantly changing. If there is a surplus of power output by the engine, the motor will be driven to generate electricity to charge the battery.
5, when going downhill or decelerating, the engine does not work, the motor as a generator to recover the kinetic energy of the car and then charge the battery.
The advantages of the parallel hybrid structure are:
1, the power of the engine does not need to go through the conversion between mechanical energy and electrical energy can be directly acted on the driving wheel, so the utilization rate of engine output energy is relatively high, when the engine is running within its optimal working range, the fuel economy of parallel hybrid is higher than that of the tandem type.
2. Through the joint drive of the motor and the engine, it is theoretically possible to achieve the perfect combination of the output power of the two to achieve a power output of 1 + 1 = 2. Although only theoretical, the actual limit output is also very high.
3, usually parallel hybrid models, only in front of / after the transmission to add a motor, in the traditional fuel vehicle based on the change is smaller, and because of the participation of the engine, so the motor and battery selection demand is not high, can save costs.
4. In pure electric mode, electric vehicles have the advantages of quiet and low cost of use. In hybrid mode, there is better power output.
Disadvantages of parallel hybrid structure:
1. Because the engine operating conditions are affected by the driving conditions of the automobile, when the driving conditions of the car change more and are larger, the engine runs under bad working conditions, and the fuel consumption and emissions are very high.
2, parallel hybrid models usually have only one motor, it can not complete the task of power generation and drive at the same time. When the vehicle continues to accelerate, the battery will quickly run out, so the engine and the motor will drive together in less condition. Then the engine is directly driven, and the fuel consumption is high.
3. The parallel hybrid system has a gearbox. Therefore, when the motor drives the vehicle alone, the power needs to pass through the gearbox, which will cause energy loss.
The representative model of the parallel hybrid system: the parallel hybrid general motor and the engine power is similar, such as the 2.0L engine power of the 10th generation hybrid Accord is 107kW, the power of the motor is 135kW, and the comprehensive power of the whole system is 158kW. There are also mild parallel hybrid systems for heavy oil weak currents, and 48V light hybrid systems for BMW 3 Series, BMW 5 Series, Mercedes-Benz C-Class, Mercedes-Benz E-Class, etc.
summary:
The biggest difference between parallel hybrid and tandem is that the engine needs to participate in the drive of the vehicle, which can achieve complete electric drive and engine direct drive, and the biggest memory point is to have a gearbox, but the participation of the motor system is not high, so it is lacking in fuel economy and emissions.