Until now hybrid production cars have added electric power to petrol engines, but Peugeot's Hybrid4 powertrain marries a 27kW electric motor with a 2.0-litre common raill diesel engine developing 163PS. The 3008 Hybrid4 is the first car to lauch using that powertrain – making it the world's first diesel hybrid production car.
The transverse front-mounted diesel engine drive the front wheels through a six-speed robotised manual gearbox and spins an 8kW alternator-generator which can recharge a nickel metal hydride (NiMH) traction battery at the rear. This drives the electric motor, which drives the rear wheels.
Peugeot's Hybrid4 diesel-electric hybrid system: 1 electric motor driving the rear wheels; 2 NiMH traction battery; 3 power electronics; 4 alternator-starter; 5 EGC gearbox; 6 diesel engine; 7 & 8 drive to the wheels.
Because the hybrid powertrain is split into discrete front and rear systems, the Hybrid4 can run in three main modes:
- diesel/front wheel drive
- electric/rear wheel drive
- diesel-electric/four wheel drive
In its default 'Auto' powertrain mode the Hybrid4 switches between these three drive modes automatically, using electric power at low speeds and switching to diesel when more power is needed or the battery is depleted. Switching between the modes is seamless, and the diesel engine starts quickly and quietly when needed. A power flow display screen and power demand meter shows what's going on.
A control knob on the centre console provides three other control strategies: 'ZEV' concentrates on electric power and delays use of the diesel engine as long as possible, 'Sport' uses shift points higher in the rev range and quickens gearshifts, and '4WD' uses both drivetrains together to provide four wheel drive – though only at low speeds.
The combination of an electric motor, battery, and diesel engine should result in high efficiency, low fuel consumption and low CO2 emissions. Peugeot claim 74.4mpg on the combined test, and 104gCO2/km – and there's a 'low emission' version with low rolling resistance tyres on 16in wheels, which returns 99gCO2/km. We had no opportunity to see how close the 3008 Hybrid4 would get to these figures in a real world test, but it should certainly deliver a fuel consumption and CO2 advantage over the pure diesel or petrol 3008s.
But that potential advantage comes with some compromises. First, there's the EGC robotised manual gearbox: in our brief test we found it produced smooth gearchanges, but would make late decisions about downshifts on hills and was sometimes caught between gears when pulling away in traffic. The second issue is the price: the Hybrid4 starts from £26,995, a premium of about £4000 compared to diesel 3008s.
The Hybrid4 makes sense for the kind of driver who will find its part-time four wheel drive particularly useful. It's also a tax-efficient company car choice, because it is classed as a hybrid not a diesel and attracts a lower Benefit in Kind tax rate (10% instead of 13%) which would save a higher-rate taxpayer around £1000 a year.
For private buyers the diesel 3008s make a more attractive choice, given their lower purchase price and the chance to choose a manual or conventional automatic gearbox instead of EGC – a choice which is sadly denied to 3008 Hybrid4 buyers.
