saab svc concept engine
 

dont know if this is a repost but has anyone seen the supercharged saab motor that can change it compression from 8:1 to 14:1 by lifting the head using a rubber bellows.Pretty badass concept.

http://www.saabnet.com/tsn/press/000318.jpg
http://rds.yahoo.com/S=96062883/K=sa...tures/svc2.jpg
http://re2.mm-a.yimg.com/image/275061638
http://www.sae.org/automag/techbrief...images/03a.jpg



http://www.saabnet.com/tsn/press/000318.html

http://waw.wardsauto.com/ar/auto_var...ression_small/

Re:saab svc concept engine
 

Looks interesting for fuel economy...

but for power??

Max. compressor boost pressure 2.8 bar (40 psi)
Maximum torque 224 Ib.-ft.
Maximum horsepower 225 hp


225HP on 5 cyl on 40 psi doesnt seem that good.

but sounds like a interesting direction to take engines.

Re:saab svc concept engine
 

That's 225hp and 225ft-lbs from a 1.6L engine IIRC. Pretty badass for OEM stuff.

Re:saab svc concept engine
 

I wonder if it has head lifting problems :P


yup its a corney joke

Re:saab svc concept engine
 

I remember seeing that like 5 years ago. cool stuff

Re:saab svc concept engine
 

i imagine that the rubber would become weak and crack way before 100k

Re:saab svc concept engine
 

The rubber doesn't actually make the cylinder or sleeve it probably just contains oil. It probably has the sleev connected to the head so they move together.

Re:saab svc concept engine
 

ya I remember reading that along time ago too, varible compression ratio. Sounds like to many moving parts to me.

Re:saab svc concept engine
 

if you look at the first pic you can see the top section of the sleeve is in the head. We were lookin at this in class today. As far as i can see the compression is also controlled by the computer controlled boost from the blower.

Re: saab svc concept engine
 

I saw that a while back too. Its actually a simple concept, essentially like lenthening one side of the block - it moves the crank centerline (and max rod/piston height) away from the head/deck mating surface. It would move the sleeves away from the crank too, since there's a nice little thing in pistons called wrist pins that allow for front to back movement that goes with a sleeve angle change. ;)

It's perfect for off-boost torque and then raises to lower comp for boost. It also would have the side benifit of retarding the timing a bit when it changes (or advancing, depends on what side raises). I doubt that reliability would be an issue with the rubber - look at the movements cv joint rubber does. It also doesn't get too hot since its not touching the head. It probably wouldn't move much in production cars, since they wouldn't be cranking the c:r to 14:1... Also, if it's ~0.2 less/more per 0.012" in head gasket size w/Hondas, a bigger bore motor wouldn't have to move it much at all. THis is probbaly refeerenced in the link, but who whats to read that? :P

As for that 40psi thing, thats just 'dazzle em with numbers' crap - a more realistic 20psi would bode for excellent fuel burn due to the air density. Thats the main principal. no boost + hi c:r = high dnesity, boost = high density. Free power from boost with off-boost high-density air. I always wanted an engine like the saab concept...