Lotus is using the 2009 Geneva Auto Show to showcase a new variable-compression engine it calls the "Omnivore." Designed to run on alcohol-based fuels as well as gasoline, the single-cylinder concept engine uses direct injection and a two-stroke operating cycle to maximize its efficiency.
An adjustable puck at the top of the combustion chamber is used to vary the compression and according to Geraint Castleton-White, Head of Powertrain at Lotus Engineering, the Omnivore has potential as a four-stoke, production engine.
"The absence of poppet valves in two-stroke engines makes the incorporation of a variable compression ratio system relatively straightforward. Our research into these systems on four-stroke engines has led us to the conclusion that while thermodynamically it is a desirable technology to incorporate, practically it isvery difficult, particularly taking into consideration production feasibility. This two-stroke engine could solve these practical difficulties and simultaneously permits a much larger range of compression ratio adjustment, with the potential to perform at a much higher efficiency when running on renewable fuels," according to Castle-White.
felonious says:
08:35 AM, 03/ 3/09
Is there anything those Lotus guys can't improve?
rkr says:
02:34 PM, 03/ 3/09
Seriously complex, but it has better potential then Volvo two variable compression (or piece block)?