• Peugeot’s technology demonstrator to be shown at British International Motor Show
• A diesel hybrid vehicle provides a 30% improvement in fuel economy over a conventional car and 25% better economy over a petrol hybrid vehicle
• Dynamic body style works well to promote the environmental benefits

Peugeot has extended its diesel hybrid technology programme, applying it to the popular, stylish and versatile 307 CC Hybride HDi, unveiled at the Geneva Motor Show in February. This diesel hybrid technological demonstrator highlights the company’s commitment to protecting the environment by reducing fuel consumption and CO2 emissions, while operating with the practicalities of real world use.

By combining a 1.6-litre HDi diesel engine with a DPFS (Diesel Particle Filter System) and an electric power train, this technological demonstrator is effectively a new step on the path to reducing fuel consumption. The 307 CC Hybride HDi joins the 307 hatchback, announced in January, to lead diesel hybrid development in readiness for possible introduction in 2010.

In addition to a hybrid powertrain, the 307 CC (Coupé Cabriolet) includes something of the hybrid in architectural terms, enabling the elegant coupé to be transformed into a genuine convertible in a matter of seconds. The 307 CC HDi offers ‘open air’ driving, thanks to the driving pleasure provided by a cabriolet, with all the environmental protection made possible by its diesel particle filter system (DPFS) and electric powertrain.

In use, the hybrid electric/diesel powertrain heralds a genuine new benchmark in terms of fuel consumption, since it combines the exceptional efficiency of the 1.6-litre HDi engine, running in its optimal operating range, with that of the electric motor designed mainly for use in town. A mixed-cycle fuel consumption of nearly 70 mpg means a gain of some 30% compared to the standard HDi model.

In addition to the all-electric operating mode at low speed around town, it provides a high level of noise and vibration insulation. This hybrid HDi power train also offers substantially improved acceleration compared to a traditional vehicle of equivalent power. The driver benefits on an ad hoc basis from the additional power from the electric motor of up to 43 bhp. For example, equipped with a 80kW 1.6-litre HDi DPFS engine, the performance of the Hybride HDi Coupé Cabriolet is roughly the same as the production model with 100 kW 2.0-litre HDi with DPFS.

The combination of a hybrid power train and a HDi diesel engine signals a real breakthrough in terms of low fuel consumption and greenhouse gas emissions. The gain, compared to a similar vehicle with a petrol hybrid power train, is around 25%.

The layout chosen for operational efficiency was the ‘parallel hybrid power train’, in which the diesel engine is used mainly to move the vehicle. It is combined with a transmission that functions in the traditional way, and an electric motor which is powered by energy stored in batteries. Kinetic energy recovered during the vehicle’s deceleration and braking phases is used to recharge the batteries. Phases of driving in the electric mode are better suited in cases where the diesel engine is less efficient, i.e. essentially in low-load situations.

DESCRIPTION OF THE POWER TRAIN

The 110 bhp 1.6-litre HDi (DPFS) engine is combined for the first time with a 2.5kW Stop & Start system (STT). The STT system ensures the standby status - possible as soon as the speed is below 37 mph – and the restarting of the engine.

The electric motor is of the synchronous permanent magnets type and is located between the diesel engine and the gearbox. It develops a continuous power of 31 bhp and a torque of 110 Nm, but its power output can be increased on an ad hoc basis to 43 bhp and 180 Nm. Combined with the inverter, it operates in a voltage range of between 210 and 380 volts. The inverter controls the torque of the electric motor by regulating the current from the batteries. The battery pack, located in place of the original spare wheel, ensures there is no alteration of the boot volume. It consists of 240 Ni-MH (Nickel Metal Hydride) cells.

The electronically controlled manual gearbox also benefits from the integration of an automated control to engage the hybrid power train. It eliminates the need for a clutch pedal and offers two driving modes; one fully automatic and one with sequential gear changes. Controlled regenerative braking, during deceleration and braking phases, is used to recharge the batteries.