Lotus Hybrid Engine Draws Manufacturers' Interest

Just the Facts:

• Lotus Engineering claims to have "significant" interest from three major car manufacturers in the dedicated range-extender hybrid engine it unveiled at the 2010 Geneva Auto Show.
• So far, the three-cylinder Lotus engine has appeared in the Jaguar Limo Green, Proton EMAS and Lotus Evora 414E hybrid prototypes.
• Lotus has significantly redesigned the engine in response to feedback from potential buyers.

HETHEL, England — Lotus Engineering claims to have "significant" interest from three major car manufacturers in the dedicated range-extender hybrid engine it unveiled at the 2010 Geneva Auto Show.

The three-cylinder gasoline engine is optimized as a generator, operating in an efficient rev range of 1,500-3,500 rpm. So far, it has appeared in the Jaguar Limo Green, Proton EMAS and Lotus Evora 414E hybrid prototypes.

Lotus has significantly redesigned the engine following this experience and in response to feedback from potential buyers, and is working with major component supplier Fagor Ederlan, a cooperative based in the Basque region, to develop the engine for series production.

"No one has signed up yet," says chief project engineer Lee Jeffcoat, but he reports interest from "several OEMS in 5,000-10,000 units annually, for a potential annual output of 30,000 engines." There's also interest from a number of small-scale carmakers for up to 1,000 engines each a year, he says.

The revised engine is now more conventional in layout, the original monobloc arrangement abandoned in favor of a design featuring a separate head and block to ease manufacture and service. But it remains unusual for having intake manifold pipes that are cast into the block, saving weight and cost.

Normally aspirated and supercharged versions are offered, mechanical boost now being favored over an exhaust-driven charger for cooling and complexity reasons.

The powertrain is now more compact and can be packaged vertically, horizontally under a floor or at any angle in between. The two versions, now of 1.3 liters rather than the original 1.2, provide 47 horsepower in normally aspirated and 67 hp in supercharged tune. A balancer shaft is optional and a two-cylinder version is also under development.

Lotus has competition from Austria's AVL and Germany's Mahle, but it believes that neither company is close to being able to put its engines into production.

Inside Line says: A dedicated range-extender engine makes a lot of sense. It is potentially more fuel-efficient, lighter, more compact and cheaper, improving the viability of extended-range EVs. It can only be a matter of time before a dedicated range-extender engine appears in a production car. — Richard Bremner, Correspondent