Working within a UK Government initiative, British engineering consultancy Zytek has developed a novel diesel hybrid powertrain that will be affordable in the most popular market segments. The new technology will allow vehicle owners to drive across London’s extended congestion charge zone for just four pence.

Zytek has developed the world's first low-cost, high-efficiency hybrid-electric drivetrain.  A demonstration vehicle, built within the UK Government’s Ultra Low Carbon Car Challenge (ULCCC), has exceeded all targets set for the programme, delivering an exceptional 85g of CO2 per km compared with 121g/km for the already exceptionally efficient standard vehicle.

“Hybrid technology is now well established as a route to low emissions and outstanding fuel consumption, but so far it has carried a substantial price premium,” explains Zytek sales and marketing director Steve Tremble. “We wanted to develop a drivetrain that would make the many benefits of hybrid drive affordable within the most popular class of vehicle. We are delighted that the ULCCC, managed by the Energy Saving Trust, has supported this programme and allowed us to demonstrate the viability of our technology.”

The Ultra-Low Carbon Car Challenge is a two year, Government-supported programme to develop an affordable, five door vehicle with well-to-wheel CO2 emissions of less than 100g/km. To be eligible, the resulting vehicle must retain the space, features and safety of a conventional car in this class, whilst simultaneously delivering adequate performance. It must also be capable of reaching production within four to eight years at a commercially feasible price.

To take the substantial step in efficiency needed to exceed the ULCCC emissions target, Zytek decided that its new hybrid should be built around a small, very high efficiency diesel engine. With common rail injection systems and sophisticated aftertreatment, the latest diesels provide quiet operation and exceptional fuel economy, combined with very low tailpipe emissions. They also work well in hybrid transmissions because the electric drive can be used to disguise turbo lag and give exceptional driveability.

The company already had a long heritage of electric and hybrid vehicle engineering programmes with DaimlerChrysler’s smart brand, so the 1.5 litre, three cylinder smart forfour CDi was the natural choice of base vehicle. DaimlerChrysler was extremely supportive and provided a vehicle and technical data for the project.

The sophisticated control system makes powerblending imperceptible to the driver, with acceleration from zero to maximum with no torque interruptions. Acceleration from zero to 62mph (100kph) takes just 12 seconds and the car can cruise comfortably at highway speeds. With perfectly balanced corner weights, the vehicle’s dynamics are also comparable with the standard car. In all ways, the Zytek dual-mode diesel hybrid offers the driving experience of a conventional small family car.