Showcasing the OMNIVORE Engine, Ideally Suited for Flex-Fuel Operation
I recently wrote about a promising variable compression ratio engine by MCE-5. Of course, they're not the only ones working on that concept; Lotus Engineering will demonstrate a 1-cylinder variable compression ratio OMNIVORE engine at the Geneva Motor Show. But what makes it special?
Technical Details on the OMNIVORE Engine by Lotus Engineering
From Green Car Congress:
The architecture features an innovative variable compression ratio system [achieved by the use of a puck at the top of the combustion chamber. This system moves up and down affecting the change in geometric compression depending on the load demands on the engine] and uses a loop-scavenged two-stroke operating cycle with direct fuel injection operating in HCCI (homogeneous charge compression ignition) mode. In an earlier presentation on the concept, Lotus said that it believed compression ratios ranging from 8:1 to 40:1 are possible.
40:1! Impressive, though they only say it's "possible", not necessarily that they'll go that far. HCCI, which is also used in prototypes by GM (among others), can help increase the thermal efficiency of the engine, making it more fuel efficient (bringing gasoline engines closer to diesel engines).
The OMNIVORE name comes from the fact that the engine is designed to run well on a variety of fuels. Geraint Castleton-White, the Head of Powertrain at Lotus Engineering, said:
The requirement to operate on gasoline in today’s flex-fuel engines limits their thermal efficiency when operating on alcohol fuels. However, the physical and chemical properties of alcohols, when compared to gasoline, provide the potential for higher thermal efficiency operation to be achieved. This single-cylinder research engine will investigate a highly thermal efficient combustion system that optimizes engine performance to fully exploit the properties of both gasoline and alcohol fuels and maximize efficiency.
So as more ethanol (and mixes of gasoline/ethanol) become available, from sustainable sources, let's hope, these types of engines could help take advantage of the different properties of the fuel to wring out more mileage out of it.
Via Green Car Congress
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