So the QA gremlin within me wonders what happens when there is a failure. Of course a system like this will experience failures, likely at a far higher rate than a purely Cam\Wheel\Belt-Chain based mechanical system. The spring likely would just return the valve to its closed position and hold it there. No valve contact to piston.
Pete
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When I looked at the youtube video it was followed by a 9 minute video featuring Christian Von Koenigsegg who described the engineering behind the freevalve system. He also describes the results of their tests with a 1.6l 4-cylinder engine. Huge power and torque boosts with lower emissions and fuel consumption. Pretty incredible.
I can't believe it has taken this long to develop solenoid actuated valves. It always seemed to me the easiest way to have variable valve timing. I suspect the issue is developing a durable enough solenoid.
I dont think it was the durability that was holding back the actuated valve, but rather the speed that they need to react to. The hydraulics were too slow or something.
I wouldn't be more worried about a failure with this valve than a conventional cam-driven valve. It looks like it has a spring return just like the cam-driven valve so if the driving mechanism fails it would just passively return to the closed position. The valve could bind in the valve guide and stick open, but so could a cam-driven valve. The added area of failure with the camless valve is a software timing issue where the controller commands the valve to open at an instant where it could collide with the piston - but this could be overcome with electrical interlocks that would open the circuit to the coil when the piston is in the danger zone. You would want to use something more durable than a mechanical switch - maybe something like hall-effect sensors or some other non-contact device, but it could be done with pretty good reliability and durability. Nothing's perfect so there's some chance that you could experience a catastrophic failure in an engine where the valve and piston could possibly occupy the same space, but you can get that on a cam-driven valvetrain too.
Nitrate wrote:I think F-1 race cars have had a set up like this for a pretty long time. RB
No, they haven't. They universally use pneumatic springs for the closing and universally use camshafts for opening. Renault did experiment with a vaguely similar idea back in the late days of the V10s but it never made it on track that I know of.