The Parallel Hybrid Drive

The Parallel Hybrid Drive










This drive is often used when an existing vehicle is "hybridized" and is characterized by the simplicity of the parallel design. Most existing parts can be integrated without having to be redesigned. This is also facilitated by the small installation dimensions of the hybrid module, which has a compact size of only approx. 15 cm in the Cayenne S Hybrid.

The Porsche Cayenne S Hybrid uses a single-shaft parallel hybrid drive concept.
The hybrid module is located on a single shaft between the combustion engine and the drive train and is only approximately 15 cm in length. A decoupler is integrated in the hybrid module so that the hybrid management system can interrupt the power transmission between the combustion engine and the E-machine.







The Porsche parallel hybrid drive concept allows for a total of six different hybrid-specific driving modes which the hybrid manager integrated in the Bosch MED 17.1.6 engine control unit selects in line with the relevant driving scenario:
1) Driving exclusively under electric power
- The decoupler is opened and the combustion engine is switched off. The E-machine is the only motor powering the vehicle.

2) Boosting
- The decoupler is closed, the combustion engine and the E-machine (as a motor) power the vehicle. The torques and power are combined to produce the total output.

3) Combustion engine powered driving with load point shift
- Option 1: The decoupler is closed, the combustion engine charges the battery and powers the vehicle (load point increase).
- Option 2: The decoupler is closed, the combustion engine powers the vehicle with assistance from the E-machine (load point decrease).

4) Coasting (unpowered gliding up to 97 mph/156 km/h)
- The decoupler is open and the combustion engine is switched off. The E-machine operates almost entirely without friction. The vehicle rolls without significant braking torque.

5) Regenerative braking (recuperation)
- The E-machine generates current (as a generator) that is used to charge the high-voltage battery and operate the vehicle electrical system.

6) Auto Start Stop function
- The hybrid management system is exclusively responsible for starting and stopping the combustion engine. The driver cannot have a direct influence here.

In the New European Driving Cycle (NEDC), the driving modes are divided as shown in the diagram below.







The NEDC Driving Cycle does not take into consideration the "boosting" and "coasting" operating modes.