Lotus has announced details of its new Range Extender engine.
The 1.2-litre, three-cylinder petrol engine is designed to be used in full electric vehicles, to either power an electric motor or recharge a battery pack.
Lotus Engineering - the automotive consultancy division of Lotus has developed the engine in collaboration with the UK Technology Strategy Board, Jaguar Cars, MIRA Ltd and Caparo Vehicle technologies. Its capabilities will be showcased in a 'large, lightweight, prestigious executive saloon with CO2 emissions of less than 120g/k'.
The Range Extender engine works in the same way as the small petrol engine fitted to the Chevrolet Volt (the basis for the Vauxhall Ampera). It doesn't ever drive the wheels, but allows an electric vehicle to travel further before it needs to be recharged.
The Range Extender engine has a maximum output of 47bhp and weighs 56kg. Lotus says that it is cost-effective thanks to its monoblock construction, where a one-piece cylinder head and block eliminates the need for a cylinder head gasket.
Durability and efficiency are also improved, says Lotus, while the lower number of parts keeps down weight and cost.
Simon Wood, technical director of Lotus Engineering, said: 'Most full electric hybrid vehicles that are currently being developed will use adaptations of existing, conventional engines, which are therefore compromised in the efficiency that they can achieve.
'Designing the Lotus Range Extender purely for use in series hybrids has allowed us instead to develop an optimised engine that has high thermal efficiency, low fuel consumption and multi-fuel capability.'