Lotus developing HCCI engine, claims 10% efficiency increase
 

Interesting to see Lotus doing work on efficiency related items, but it seems they are working on their own gasonline HCCI (homogeneous charge compression ignition - ah la diesel) engine. Its also claimed that it can run on almost any liquid fuel because it has variable compression ratio via a movable puck the the head.

Lotus: Omnivore engine is 10% more efficient with more to come - Autoblog

http://ecomodder.com/forum/attachmen...1&d=1260542017

...a compression ratio "puck"?

...I've wondered why two "opposed" cylinders with variable "timing" on the dummy-compression piston hasn't been popularized more...especially with today's smart ECU controllers.

Daox -

I'd like to see a comparison chart between that one and the one that GM has had "in the works" for a really long time. It sounds like Lotus is claming to solve the HCCI puzzle.

CarloSW2

That would be great to see. How long has GM been working on their HCCI anyways? I know its been quite a few years, but unsure of exactly how long.

Traditionally 2 stroke engines generate 50% more power and use 50% more fuel than 4 stroke engines. If they eliminate the fuel usage problem inherent in 2 stroke carbs that give it such terrible emissions then it sounds good to me. Having a working prototype is probably Lotus' main point. But increasing compression from 10:1 to 40:1 is pretty handy. 10% improvement on Gasoline means if it ran on Alcohol or Diesel it could be even better. Mixed with turbocharging we're talking about cutting engine sizes in half and then by a third. Which means a theoretical 2.0l engine could be replaced by a TurboCharged 660CC motor! :thumbup: And run on just about any fuel of your choosing.

Mixing oil with gasoline is obsolete already since they switched most 2 strokes here in the US over to wet sump years ago. Some of the comments, sheesh :D.

Yeah, really. :) But then I thought about it a little bit and realized it wouldn't be that hard to do. All you need is a bit of moveable real estate on the cylinder head side of the combustion chamber. Move it further into the chamber to increase compression ratio, and move it out of the combustion chamber to reduce it. It can't be a flat plate, it needs to have sides; make it round and you have a "puck".

I have one of those, a two stroke diesel model airplane engine that fits in the palm of your hand with a nob on top to change the compression.

Lotus new development engine
 

An engine developped by Lotus for mixed fuel ,variable compression, two stroke, high efficiency.

Run the engine

http://www.grouplotus.com/manageshow...sthru/8628.swf

...excellent technical illustration of "...what's going on..." but I have to worry--too many mechanically 'moving' things for my mechanical-comfort-zone.

Maybe you've never seen how the various VTEC systems work. They can be pretty complicated, and people routinely get multiple 100K miles out of the engines.

I'm fascinated -- and a bit confused -- by the exhaust port Trapping Valve.