TexasDude74

Caterpillar used similar technology in their ACERT diesel engines. They did not replace the camshaft but were used as a sort of VTEC aimed more at reducing emissions than gaining performance and only opened the valves, still relied on spring pressure to close them. Many people, myself included, have repurposed the system to hold the intake valves open longer verses opening them sooner as designed with great results. Their system has been known to exceed two million miles.

TexasDude74

Actuators won't slam the valves closed nearly as hard as a valve spring will. Valve springs are chosen with enough pressure to control the valves in the worst case scenario and then plus some. With actuators, every aspect of the valve event is nearly infinitely adjustable. It's the future of the performance oriented internal combustion engine. Electric motors are the end game for everything else unfortunately.

123quattro

I know you understand this, but it's the valve spring making the valve follow the cam profile.

TexasDude74

True, and the current generation of stuff in production still needs a spring. The actuators just open the valve a little farther or change the timing events a little. What this video is talking about is the next generation of this technology which will get away from needing a spring. That's when things get interesting.

WallyP

If the valves don't have to follow the cam, you don't need nearly as much spring pressure slamming the valves shut. I would expect the actuators to be able to exert variable opening/closing forces as needed - valves can be much lighter, reducing forces even more.

FiveElements

Seems accurate to me. If the lift is a square profile, the valve does not need to be under heavy spring tension to follow a rounded cam lobe. Why would a valve need such heavy tension if it's pneumatic? The value seat just needs to make a good seal without leaks. The key is a good CPU and very reliable timing sensors on the crank.

Bjbpe

Back in 1954 Mercedes re-entered the grand prix competition with the W196, a car with a straight eight laid on it side with power taken out between the fourth and fifth cylinder; essentially a v8 that was cut in half and set end to end. It had desmodremic valve gear where the valves were opened and closed mechanically without the use of springs. The car was a real screamer, winning all the events until a "civilized" version of the car, the 300SLR left the track killing scores of people, Mercedes stopped racing that very minute.

17prospective buyer

Cool story bro.

cpayne

Looks like ford may try this

mark kibort

good point. PLUS, its pretty hard to get enough compressed air in a tank to provide any boost at all. a v8 might take 500cfm at 6000rpm. that's a pretty big tank

Tony

...and we all complain about Vac leaks in our HVAC or intakes.

Wonder what the symptoms are of a minor leak in the lines leading to the #2 intake valve of the 5th cylinder....or is it the #1 exhaust valve in the 7th cylinder? ....uh..wait..whats the firing order again?.

TexasDude74

Agreed, I don't envision anything worthwhile developing with a storage system. But, engine compression braking would be awesome on a track car, particularly an awd model. Diesels can generally generate a minimum of 70% of their rated horsepower in braking force. So a 500 horse engine can generate at least 350 hp in braking force.

Lizard928

Diesels work on nearly double the compression we are working with. So we might get 35-40% I'd think.

FiveElements

I think they are looking for short boosts of power. Seconds. Not necessarily long durations like a turbo may be capable of. Air does compress down, a lot... to the point of becoming a liquid even. Then injection of that air may be outside of the main intake plumbing. Perhaps through one of 4 valves which is not a part of the intake system where leaks are a concern.