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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 demonbug on Friday February 28 2014, @11:47PM

    by demonbug (3529) on Friday February 28 2014, @11:47PM (#8891)

    First, valves generally only switch twice per full cycle - intake valves open and close on the intake stroke, and remain closed for the remaining three strokes (in a 4-stroke). With two strokes per rotation (so two rotations per full cycle), you're only looking at 3,000 cycles per minute at 6,000 RPM, or ~50Hz (rather than 6KHz you stated).

    As for the efficiency gain, it is less about drag and more about timing. Depending on throttle position, engine speed, intake pressure (boost), and probably an assortment of other variables, the valve lift and timing are going to vary widely for maximum power and/or efficiency. With variable timing from using different cam lobes (or sculpted lobes to allow more gradations) there is some variability available to engines, but nowhere near the same range as this would offer - there just isn't a practical way to program all that into an analog camshaft. Plus, on the efficiency end, you would be able to just seal off whatever cylinders you don't need at the moment - and you could even vary rotation by rotation which cylinder is shut down to spread wear evenly and improve balance.

    That said, their 50% number does seem pretty high; but maybe they are comparing to an ICE with fixed valve timing and port fuel injection. Combine the infinitely variable valve timing and lift with direct fuel injection, and I can easily see that 50% increase in efficiency.

  • (Score: 1) by NovelUserName on Sunday March 02 2014, @03:03AM

    by NovelUserName (768) on Sunday March 02 2014, @03:03AM (#9367)

    Well, that's embarrassing- On top of forgetting that the valves don't actuate each cycle, I made the elementary mistake of forgetting that minutes aren't seconds when converting RPM to Hz.

    Thanks for pointing that out!