Hybrids by retro-fit

UK company's makeover approach could "convert conventional cars"

Can your current car boast the green credentials – and fuel economy – of a fuel/electric hybrid? If not, there may be a solution on the horizon, if a new conversion system lives up to its promise.

The Motor Industry Research Association (MIRA) which, despite its name, is an engineering and design consultancy company, is currently demonstrating the conversion technology on a Skoda Fabia – deliberately chosen to show that there need be nothing special about the base model. The resulting H4V (Hybrid Four Wheel Drive Vehicle) claims to do an average of 64mpg (which is 61% better than the standard Fabia’s 39mpg) while the top speed and acceleration remain broadly similar. Emissions are reported as 39% lower.

The key feature is a removable Li-ion battery pack arranged into three portable 30kW cassettes, powering the two 50 bhp electric motors which drive the car’s rear wheels. In electric-only mode it has a range of 15 miles – but here’s the twist: it can also use its petrol engine to drive the front wheels. In short, a conventional car becomes nothing less than a plug-in hybrid 4x4.

The petrol engine, and a regenerative braking system, will help top up the battery pack while the car is running. But you can get a full recharge from the mains in 30 minutes – or simply swap over the cassettes for ready-charged ones. “You can obtain electricity from your domestic provider far cheaper and greener than from a car engine, so plug-in hybrids make sense,” says MIRA’s Derek Charters. What’s more, he adds, “we’ve removed the main limitation of the plug-in hybrid by allowing the battery pack to come to the mains, rather than having to park right next to a socket, which is difficult if you live in a terraced house or flat”. The battery pack could also double as a power source for ‘external devices’, and the fact that such delights as electric jet-skis and quad bikes get cited suggests an appeal well beyond the devout greenie market.

So when and where can you buy one of these conversion kits? Well, actually, you can’t. The H4V is really a concept evaluation tool, rather than something destined for public sale. The Energy Saving Trust helped pay for the project through its low carbon R&D programme (funded by the Department of Transport) and, as the EST’s chief executive Philip Sellwood says, what MIRA has designed is “a new system allowing hybrids to be more flexible and practical for every day use”. But that’s not the end of the story, because MIRA does now plan to apply the lessons it has learned to help create more commercially oriented hybrid projects. – Roger East and Andrew Williams

24 June 2008

Andrew Williams and Roger East