As oil prices rise, manufacturers once again wonder if their fuel guzzling cars will ever start to sell again.
Specialists in lightweight performance cars, Lotus turned its attention to hybrid electric-petrol engines several years ago: heavy electric cars have short battery life. Lotus' speciality in vehicles that weigh little more than a pocket handkerchief means, brutally, that lighter vehicles go faster and, on batter power, further.
And Lotus has decades of experience of extracting the best performance from small engines - often embarrassing competitors with much more grunt. Colin Chapman's philosophy that brain power at the design stage counteracts more horsepower at the production stage is alive and well.
Now the company has gone one stage further and announced its "Range Extender" engine.
It's got three cylinders and it's only 1.2 litres. And it has an electric motor, too. Here's the techy bit:
" The Lotus Range Extender engine is optimised between two power generation points, giving 15 kW of electrical power at 1,500 rpm and 35 kW at 3,500 rpm via the integrated electrical generator. Its low mass of 56 kg makes it ideal for the series hybrid drivetrain configurations for which it is designed. The engine uses an optimised two-valve port-fuel injection combustion system to reduce cost and mass and, in line with Lotus Engineering's extensive research into renewable fuels, can be operated on alcohol-based fuels or petrol."
Paul Newsome, Managing Director of Lotus Engineering said: "The Lotus Range Extender concept we have created with its optimised combustion and compact, low mass, low cost construction is a clear demonstration of the expertise and progressive approach Lotus takes for its own research and for its clients."
The engine is designed to be manufactured in relatively simple production plants, and using parts that can be sourced from low volume suppliers - that translates into the possibility of production in e.g. the production plants of Proton, Lotus' parent company. It's an all aluminium engine - and Proton has experience of building those: it's a Lotus designed aluminium power plant in the Proton Gen2 and related cars.
It's designed to run on ethanol, methanol and 95 RON unleaded petrol - the formula that the Malaysian government recently decreed must be made available across the country and which is leading to the phasing out of high-octane fuels such as Shell V-Power as 95 and 97 octane fuels become the norm.
But going back to the Lotus obsession with weight: the engine's dry weight is just 56kg. This is achieved in part by a monoblock construction that removes 17 parts and the need for a head gasket as well as improving the routing and effectiveness of the water jacket for cooling. The engine includes an integrated exhaust manifold - that saves weight and reduces both gaskets and risk of leakage - and saved a further 18 parts.This leads to reduced emissions on start up - and reduces production cost.
Because of the unitary construction, the whole engine is smaller than a standard 1.2 litre engine.
And the weight savings do not end there: the generator is attached to the crankshaft. It constantly recharges the batteries. That translates into smaller, lighter batteries.
But the engine is not destined for cutesy little cars: this is, after all a Lotus engine. It's designed as a part of a project to make "limo" cars less of an environmental nuisance: the Lotus Range Extender engine has been developed as part of the 'Limo-Green' project funded by the UK's Technology Strategy Board, a collaboration between Lotus Engineering, Jaguar Cars Ltd, MIRA Ltd and Caparo Vehicle Technologies, demonstrating a large, lightweight, prestigious executive saloon with less than 120 g/km CO2 emissions.
And, one hopes, taxis in downtown Kuala Lumpur.
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