Lotus Engineering has developed a new engine especially for hybrid cars, and will be displaying it at the Frankfurt Show next week.  Jaguar will reportedly be the first company to use the engine in a production vehicle.

The Range Extender, as it's called, is a 1.2-litre petrol (or ethanol or methanol) unit which develops a maximum of 47bhp. That's only about two-thirds of what a conventional engine of that size would normally be expected to produce, but there's a good reason for that. The Range Extender does not rev beyond 3500rpm - which is about as far as most drivers will go in everyday driving - and other 1.2s have to go a long way past that to achieve the normal 70bhp or so.

It's also important to point out that 47bhp is what the engine can achieve on its own. The total output would be considerably higher, enhanced by the power of an electric motor. Power-to-weight ratio is also crucial here, and this has been a key consideration in the design of the Range Extender. At just 56kg it is remarkably light, and Lotus has achieved this figure by making the engine block, cylinder head and exhaust manifold out of a single aluminium casting.
Apart from the weight advantage, this method of construction also reduces the size of the unit and its cost of assembly, while improving durability and emissions.

Servicing it may be another matter, though since more than 30 parts required in a conventional engine are no longer required in this one there will at least be less to service.