http://www.sciencedaily.com/releases/2007/...70510093248.htm
Sounds pretty interesting, but I'm a computer geek, not an engine designer.Quote:
A key portion of his research, based at Purdue's Ray W. Herrick Laboratories, hinges on designing engines so that their intake and exhaust valves are no longer driven by mechanisms connected to the pistons.
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Don't F1 motors use compressed air to open the valves???
I think they did, but I believe they have gone to hydraulics. I could be wrong....but I seem to recall one of the reasons F1 cars have such high "idles" is the need for high hydrauliic PSI. But I think they do vary time open and such electronically.
F1 cars went away from valve sprigs when the revs started getting in the 14,000 roange, if memory serves me (which it probably doesnt't, LOL)
The interesting aspect of this artical was, to me, the concept of the charge and lack of charge variance, and the reinduction of exhaust, all said to lower average combustion temps. The method of valve actualion wasn't discussed though, sadly.
Ever wondered how a model aircraft motor worked? It's an application of HCCI technology. I know that HCCI has been worked on at Sandia NL in Livermore for quite a while now. HCCI basically requires an exact knoledge of the combustion chamber temperature and modulate the effective compression ratio so that the mixture ignites at TDC. Because ignition happens virtually simultaneously through out the combustion chamber, hot and cold spots don't form and NOx is minimized. The compression ignition results in an increased thermodynamic cycle and the mixture doesn't need to be as fuel rich, and acutally can be very lean. The test mule at SNL was based on a Honda 1.6liter, which makes sense given Honda's CVCC production motor history. As for variable cam goemetry, that's old news, the VANOS system only uses the motor as a source of rotation, the cams are acutally driven by electro-hydraulic actuators.
James
Quote:
Don't F1 motors use compressed air to open the valves???
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The valves in an F1 engine are opened by the cams. They are closed by pneumatic springs. The hydraulics control everything from the trans and clutch to the throttle.