Peugeot's diesel hybrid

Details of the world's first diesel-electric hybrid have been revealed by Peugeot.

Using the 3008, Peugeot's new Nissan Qashqai rival, as a basis, it will have a front-mounted diesel engine and an electric motor in the rear, which can function independently or together. The car is therefore capable of being driven at the front, rear or through all four wheels.

The French company is currently honing the software that controls the drive system, and admits it still has 'some very tricky things to do', but the hybrid is expected to go on sale by 2011.

One of the biggest challenges with a diesel hybrid is to make the transition between the two propulsion systems smooth, since both diesel engines and electric motors develop maximum torque at low revs. Start-up is also more difficult with a diesel hybrid.

The way forward
However, Peugeot is convinced it's the right way to go because of the fuel consumption and CO2 benefits it brings around 35% better average mpg than a comparable petrol car overall, and 50% in town.

Peugeot claims the 3008 Hy4 already achieves almost 70mpg with emissions of 109g/km, and is convinced it can reduce CO2 to a maximum of 100g/km in a five-seater four-wheel-drive car weighing 1600kg by the time it goes on sale in 20 months' time.

The decision to give the car all-wheel-drive capability was based on purely commercial reasons. The Hy4 will cost between 30,000 and 40,000 (at least 27,250 at current exchange rates), and Peugeot says it could cut this by only 15% at best by opting for a front-drive system, such as that in Toyota's petrol-electric hybrid, the Prius. 'It is easier to sell a car at this cost as an SUV with 200bhp and four-wheel drive,' Peugeot says.

How much and how does it work?
According to Peugeot, 'the Hy4 will not be sold at a loss like the early Toyota Prius, but as you begin to sell the technology the cost comes down. Then you can start to think about more widespread use on a two-wheel-drive hybrid.' The drive system has been developed to work on any car using the Peugeot-Citroen medium- and large-car platforms.

Its fundamentals are a 163bhp 2.0-litre diesel with a particulate filter at the front and a 37bhp electric motor at the rear. Together they develop a maximum 370lb ft of torque, delivered through a six-speed automated manual gearbox.

There are four drive modes:
• ZEV, which gives you up to a mile-and-a-half on electric power alone for town use, with zero emissions.
• Auto, in which electronics automatically decide which power source or sources drive the car.
• 4WD, when both engines operate in tandem when required.
• Sport, which gives faster gearshifts at higher engine revs. It's the Sport function which is currently giving engineers most software headaches, as we discovered in a drive of an early prototype.