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posted by Dopefish on Friday February 28 2014, @10:00AM   Printer-friendly
from the rev-up-and-burn-out dept.

germanbird writes: "Jalopnik has an interesting article up about Koenigsegg's Prototype Camless Engine. The engine uses pneumatic actuators rather than a cam to open and close the valves in the engine. The engineers behind this claim that it can provide "30 percent more power and torque, and up to 50 percent better economy" when applied to an existing engine designs. The article and some of the comments also mention that some work has been done with electromagnetic actuators to accomplish the same task. It may be a while before this tech is mature enough for passenger vehicles, but maybe if a racing series or two picked it up, it might give some of the manufacturers the opportunity to work the bugs out?

Not sure this is on topic for SoylentNews, but the article brought me back to my introduction to engineering course in college. One of my classmates was a car nut and I remember a discussion with an EE professor one day about the potential (or actually lack thereof due to performance issues) for using electric actuators to open and close valves."

 
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  • (Score: 1) by mrkaos on Saturday March 01 2014, @02:30AM

    by mrkaos (997) on Saturday March 01 2014, @02:30AM (#8936)

    Its interesting to me because they selected pneumatics rather than hydraulics.

    and to me because they chose those over electromagnetic.

    I'm skeptical of the claims of a 50% efficiency gain. The camshaft generates nowhere near that much drag, and you still need to power the pneumatic system, which the old motor doesn't. Most of this putative gain then has to come from being able to adjust the valve timing and lift dynamically.

    I'm not, though this is not a criticism of your point, just that ICE are so damn inefficient that improving them is a matter of picking what you want. The induction of the system is a big place to do this and it's not a matter of drag but one of *volumetric efficiency* or VE.

    A cam is only efficient in a very narrow band of RPM and timing the opening and closing of valves dictates the VE of the engine. So with a cam your valves are open for the same relative duration or RD (in percentage terms to the length of the stroke) at any RPM. What this mean is that engines with a cam has a great power range for a limited RPM.

    However, you need the opposite characteristics to have the power band cover the entire rev range. At low RPM the valves short be open for a shorter RD and for higher RPMs a higher RD. There are also post-combustion things you can do so more air is available for the next combustion cycle. This, in a nutshell is why it's possible to start to attain better efficiency in an engine with a system like this.

    Also you are able to shut down cylinders that you don't need during cruise, so you use less fuel. Ahhh we do that now with engine management systems - which is true except that what they don't do is shut down the 'compression' cycle and power is lost there.

    Many of the efficiencies won't be *ahem* driven into ICE designs without radical new EMS, but apart from being disappointed that my own design will probably never see the light of day, this is a great step forward.

    --
    My ism, it's full of beliefs.