This article is about the 1st gen HYbrid4 system. HYbrid4 is PSA Peugeot-Citroën's in-house developed TTR hybrid powertrain system, shared between the two manufacturers. It commonly takes the form of a diesel engine powering two wheels coupled with an electric motor powering the other two wheels to provide a 4WD hybrid with a short fully electric range. The system made its production debut on the Peugeot 3008 HYbrid4 in 2012, emitting 99 g of carbon dioxide per kilometer. The 3008 HYbrid4 returns combined fuel consumption of 3.8 litres/100 km, beating the smaller Toyota Prius. It also operates in four driver-selected modes: Auto, Sport, ZEV and 4WD. This technology is not as widespread in Europe as it is in the United States and Canada.
Operation
The Hybrid4 powertrain combines a 120 kW/163 hp 2.0 litre HDi FAP EURO5 diesel engine with a 28 kW electric motor. The powertrain offers 4 working modes: AUTO, in which the vehicle strives for the best fuel economy - throttle response is slow and the automated manual transmission shifts early, furthermore the vehicle switches to ZEV mode as often as possible; SPORT mode offers a combined power output of 200 hp and 500 Nm at speeds up to 120 km/h, throttle response is very aggressive and the engine revs up to 4000 RPM before upshifts; 4WD mode keeps the HDi engine running constantly and charging the high voltage battery to offer constant AWD with 60:40 split at speeds up to 120 km/h; ZEV mode is available if the high voltage battery is at least 1/3 full. In this mode the vehicle moves only via the rear electric motor and the performance is limited. ZEV mode is available at speeds of up to ~60 km/h with moderate acceleration, the range on a full charge is about ~2 km, the A/C compressor is automatically switched off in this mode. If the driver presses the accelerator beyond a certain point, the HDi engine restarts automatically as to offer better acceleration and the vehicle goes to AUTO mode. Auto Start-Stop is part of the HYbrid4 system and is available in all modes except for 4WD when the engine is constantly running so that the reversible alternator can top up the battery and provide constant rear drive. The engine automatically shuts down whenever possible, when coming to a stop the HDi engine shuts down at speeds below 30 km/h. The Auto Start-Stop function is possible with the use of the BOSCH SMG 138/80 reversible starter-generator motor. Restarting can occur at any moment, if the HYbrid4 control unit determines that additional power is needed; or the battery needs to be topped up; or the A/C compressor needs to kick in. The engine also restarts when the battery is fully charged and the vehicle is going downhill, as to offer additional engine braking, no fuel is used in this mode, but ZERO EMISSION is not displayed, as the HDi engine is rotating.
HV Battery
The high voltage battery consist of 42 packs of 4 D-size SANYO batteries. The nominal charge of the battery is 201.6 V, but operates in the ~168–270 V range depending on the state of charge and acceleration/charging demand. To offer a longer battery pack life the HCU never charges the batteries to their full capacity, nor discharges them under 20%. The battery pack has an independent air cooling system which can operate at different flow rates depending on the cooling requirements of the unit. The cooling system can be operative even if the vehicle is locked; operation noise and a warm draft can be felt at the left rear quarter panel of the car.
Rear electric drive
The rear electric drive was co-developed by PSA Peugeot-Citroën, Bosch and GKN. It has an integrated clutch mechanism that disengages the rear drive at speeds over 120 km/h to provide less drag and better fuel efficiency at highway speeds. Reverse gear is not mechanical, instead the current going through the electric motor is reversed.
Bosch SMG in HYbrid4
The Bosch SMG 180/120 electric motor is used as the traction motor in the HYbrid4 system. The unit weighs only 32 kg and is a permanent magnet synchronous motor. In the HYbrid4 system it can deliver up to 27 kW and 200 Nm of power to help provide lower fuel consumption in AUTO and ZEV mode, better grip in 4WD mode and enhanced acceleration in SPORT mode. HYbrid4 incorporates another Bosch permanent magnet synchronous motor, the SMG 138/80 in the engine compartment to serve as a high-voltage starter/alternator for the start-stop system. It is also responsible for supplying power to the rear-wheel drive and charging the high voltage battery.
