P0-P4 motor architecture analysis, motor position and combination, P3

After understanding the P2 motor architecture, it can be seen that because it needs to pass through the gearbox, the efficiency of pure electric drive and kinetic energy recovery is compromised. At this time, we need to look at the P3 motor architecture.

The P3 motor architecture places the motor behind the gearbox, which can be at a certain distance from the gearbox, coupled with the output shaft of the gearbox, and transmitted through gears or chains. The entire path is engine-clutch-gearbox-motor-reducer-wheel. In terms of function, the P3 motor can realize brake energy recovery and pure electric drive vehicles.

Because the P3 motor architecture has separate space requirements, theoretically, rear-wheel drive vehicles are more suitable for the P3 motor architecture, after all, they can provide more space.

Advantages of P3 motor architecture:

1. Pure electric drive is more efficient because the P3 motor is located behind the gearbox and connected to the drive shaft. Therefore, it can drive the vehicle more directly and efficiently under pure electric drive and reduce kinetic energy loss.

2. The kinetic energy recovery capability is better. When the vehicle is braking or going downhill, the braking energy generated by the wheel reversal can be more directly fed back to the P3 motor through the drive shaft for charging.

Disadvantages of P3 motor architecture:

1. Compared with P0-P2 motors, P3 motors cannot be integrated with the gearbox or engine, so the entire structure requires a separate space to store, which requires more vehicle body space.

2. Because the P3 motor is separated from the engine by a gearbox and a clutch, the motor cannot be responsible for starting and stopping the engine. Therefore, it is necessary to add a motor in the P0 or P1 position to fill this functional deficiency. At the same time, the power of the motor cannot be too low.

3. Although the P3 motor is behind the gearbox, it still needs to drive the gearbox in front in the case of pure electric drive, so the gearbox will cause some unnecessary energy loss.

Since the gearbox is in an awkward position in the P3 architecture, it was replaced. So the engineers removed most of the transmission gears, leaving only a few reduction gears. Then the P1+P3 motor combination formed a P1P3 hybrid system, and the Honda i-MMD hybrid system is based on this architecture.

The working modes of the hybrid architecture can be divided into:

1. Pure electric drive: The battery powers the P3 motor, the clutch is disconnected, the engine and P1 generator do not work, and the vehicle is driven solely by the P3 motor.

2. Engine direct drive: When the vehicle's driving conditions meet the engine's high-efficiency range, the clutch is coupled and the engine will drive the vehicle alone. However, because there is no transmission, it is difficult for the engine to reach the high-efficiency range, so this mode is relatively rare.

3. Series hybrid: The engine, P1 generator and P3 motor are connected in series. The engine drives the P1 generator to generate electricity, and transmits the electrical energy to the P3 motor to drive the vehicle.

4. Parallel hybrid: The engine and P3 motor run together to drive the vehicle.

5. Kinetic energy recovery mode: When going downhill or braking, the wheels drive the P3 motor to reverse and charge the battery.

It can be seen that the P3 motor can achieve better results when combined with motors in other positions.

Summarize:

Compared with the previous motor architecture, the P3 motor architecture no longer needs to pass through the gearbox, so the pure electric drive and kinetic energy recovery efficiency are higher. The disadvantage is that it takes up space and requires motors in other positions to assist. Compared with the single P3 architecture, adding a motor in the P0 or P1 position can be considered a good hybrid system.