ADDZEV launched

A collaboration between leading UK automotive engineering organisations has resulted in the development of the first retro-fit hybrid conversion of a combustion-engine vehicle.

Known as the Affordable Add-on Zero Emissions Vehicle (ADDZEV), the project, which was first revealed by The Engineer in November 2008 (click here for details), demonstrates how it may be possible to convert much of the UK vehicle-fleet into hybrid vehicles.

Developed to reduce the carbon emissions of inner-city driving, the ADDZEV system was perfected using a standard Vauxhall Combo van.

Designed to operate as a ‘Plug-In Hybrid Electric Vehicle’ (PHEV), the development team retained the existing conventional front-wheel-drive system of the Combo but added an electric drive, powered via Exide’s low-cost advanced lead acid batteries, to the rear wheels.

This transformed the van into a hybrid vehicle, capable of achieving an all electric range of more than 20km from one charge.

Conceived by a consortium from Cranfield University, Millbrook Proving Ground, Provector and Oxford University, with battery advice from the European Advanced Lead Acid Battery Consortium (EALABC), the project team behind the ADDZEV believes that the technology could be scaled up for larger vans and even city buses.

The electric-only drive is powered through twin liquid-cooled motors with a maximum power of 100kW for maximum gradeability.

It is mounted in a discrete sub-frame under the rear floor of the vehicle and has been limited to propel the vehicle at speeds of up to 60km/h.

For out-of-town driving or higher speed operation, the existing front-wheel-drive diesel power unit provides conventional operation.

It can also be configured to switch manually between modes, enabling selection of ultra-low emission operation in a low-emission zone or city centre.

The batteries are charged through specially devised control software and power-management systems created by Cranfield University and Cambridge-based Provector.

As a result, drivers have two options for charge - either by connecting to the electricity grid or via the internal combustion engine that generates and stores energy when the vehicle is in motion.

This could reduce the typical fuel-cost of a small delivery business by 40 per cent compared with operation on traditional fossil-fuels.

The technology, which can be retro-fitted onto a wide range of vehicles, has performed well in final testing at Millbrook.

Andy Eastlake, head of laboratories at Millbrook, praised the team, saying: 'This has been a diverse project with many challenges, but by bringing together the technology providers, system integrators and the development organisation to connect the supply chain directly to the vehicle operator, we have been able to focus not only on what can be delivered but, importantly, on what the end customer wants to operate.'

Conducted as part of the Low Carbon Research and Development programme run by the Energy Savings Trust (EST), the project was jointly-funded by the Department for Transport and the European Advanced Lead Acid Battery Consortium.

'The project has shown the untapped environmental potential of modifying existing urban-vehicle designs to hybrid,' said Nick Vaughan, head of the Department of Automotive Engineering at Cranfield.

'In the current economic climate, relying on the gradual penetration of newly built vehicles to reduce carbon emissions will not deliver much-needed carbon savings in the short term.

'Our target for ADDZEV was to demonstrate what could be achieved with the existing urban fleet.'