If you shift the paradigm but bring some of the old paradigm to the new paradigm, have you fully shifted to the new paradigm? Probably not, and Lotus apparently agrees. Most hybrids, even the extended range type, have simply added new technology to old. But the Lotus Range Extender engine is a new design developed specifically for its serial hybrid application and developed as a unit with its generator.
More famous for its sports and race cars, Lotus' new engine/generator combo has a variety of features, some as old as the automobile itself, to reduce size, weight, and cost while improving emissions and increasing engine durability.
One of Lotus' new-old elements is monoblock construction, with the cylinder head and engine block along with the exhaust manifold in one casting. Because its sole function is to generate electricity, it can effectively be a single speed engine--another throwback to early automotive days--although Lotus engineers have optimized the engine to two rpm points. At 1500 rpm, the 1.2-liter 3-cylinder Range Extender engine and generator produce 15 kW of electrical power, and at 3500 rpm, 35 kW.
To save mass, the monoblock is made of aluminum. The engine also uses two-valve port injection, optimized for its constant speed operation. The engine weighs just under 125 pounds. The monoblock construction, eliminating the need for a head gasket, also reduces total parts count for the engine by seventeen.
Lotus developed the Lotus Range Extender with more than a casual eye on cost, which has been a significant challenge for series hybrids, noting that not only is the Range Extender a cost effective design, but its low weight will allow the downsizing of expensive batteries without compromising range or efficiency. Lotus also designed the engine so that parts could be easily produced by low volume production suppliers, which Lotus says offers "a fast route to market for original equipment manufacturers wanting to source a dedicated range extender for series hybrid vehicles."
The engine, which will be introduced at the Frankfurt auto show, was 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, which demonstrates "a large, lightweight, prestigious executive saloon with less than 120 g/km CO2 emissions."
Says Paul Newsome, managing director of Lotus Engineering says, "The engine concept we have created with its optimized combustion and compact, low mass, low cost construction is a clear demonstration of the expertise and progressive approach Lotus takes for its own research for its clients."
Or in other words, Lotus didn't develop this engine for a particular customer, but hey, will you take a look at that paradigm.
Illustration: Lotus Range Extender engine, courtesy Group Lotus.
Subscribe to get an email alert for the latest article by John Matras, or follow John on twitter @AutoReview.
Comments