Saab Variable compression Engine
Turbo Mini Forums

I remember reading about this in the trade/engineering press a while back, but nothing since. Googling it doesn't suggest it's in production yet - anyone know anything?



A good description and explanation:
http://www.saab.co.uk/main/GLOBAL/en/vepsilon/

Don't know if they got it to production, but I remember looking at a model of it at the Motor Show a few years ago now.

It works by the head and "barrels" (for want of a better description) being able to pivot about a fulcrum that exists "halfway" up the engine. The crankshaft exists in a separate casting at the "other" side of the fulcrum. By opening up the angle, the pistons do not come to the top of the bores, hence lowering the CR. Vice versa, if the angle closes, the pistons get further up and the CR is higher. There is a rubber bellows between each part of the "block".
When I looked at it, the thing that struck me was the force that would be exerted on the fulcrum pivot when any one cylinder fired or compressed.
But still very clever stuff indeed.

yeah i remember seeing this about 4 years ago when i was doing one of my HNC projects in thermodynamics, there was something to do with vauxhall but I can't remember what it was now??

GM own Saab...

Its a good idea, but as far as I know they couldn't sort out the sealing problems - and the HUGE frictional losses.

Alex

AlexF

Dave, if you're interested in forward thinking engines check www.sixstroke.com how about one of those heads?

Bugger off, I'm getting there.

Here's a good description: http://www.fs.isy.liu.se/Lab/SVC/

[X] nail here for new monitor

prodrive were farting about with this at the year before last's motorshow

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"