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http://jalopnik.com/5884144/swedish-supercar-to-debut-radical-engine-of-the-future


Swedish Supercar To Debut Radical Engine Of The Future

Swedish supercar manufacturer Koenigsegg told Car & Driver that they are engineering their twin-turbo V8 engine to run without a camshaft. The far-flung world of infinitely variable engines will soon be upon us.
While regular engines use a camshaft and a valve spring, Koenigsegg's camless engine will shoot the valve open with pneumatically driven actuators. It's expensive, it's loud and it's crude, but it's infinitely variable as well as significantly lighter than a camshaft. In the end, you have an engine that is 30% more efficient than what is in road cars (and nearly all race cars) today.
Working with Sweden's Cargine Engineering, Koenigsegg is on the cutting edge of engine tech, so it's no surprise they admit they're working through noise and reliability issues. The thrill remains that for decades this technology has existed only in the secretive world of Formula One. Now it's finally coming to the world of road cars, even if it is just for monstrously expensive Swedish hypercars.
A detailed explanation of pneumatic valves and camless engines can be found here at ScarbsF1.com.
Photo Credit: Eddy Clio


F1 Engines _ Valve technology
All F1 engines have used pneumatic valves for some time, first introduced by Renault on the late versions of the their V6 turbo engine.


Wire spring valve

Previously wire valve springs have been used, they use a coil spring (13) to return the valve (1) to a closed position after the cam has retarded. They required huge amounts of the detail development on their shape and material to reach the rev limits of around 15k RPM. The pressure to deliver power from 3.5l and later 3.0l engines required ever higher rev ceilings and metal springs could not longer be developed at the same rate as the rest of the engine.


Pneumatic valve spring

Pneumatic systems use conventional cams operating the valve (4) via a shim\bucket or finger follower, the valve spring pocket is replaced with a chamber (28) pressurised with nitrogen (held within a cylinder in the sidepods) that runs at a constant pressure to return the valve when the cam timing retards. You often see the teams suffer a loss of pressure in the races through leaks in the system, the driver comes in and mechanics re-pressurises the pneumatic circuit, this rarely works for more than few laps. Also when Engines are changed the un-installed engine needs a remote gas cylinder connected in order for the valves not to drop and hit the pistons.


Wire spring vs Pneumatic valve comparision



Renault Electro-Hydraulic (Camless) valve actuation

Renault have not planned an Electro-mechanical system, which was commonly believed to use actively controlled magnetic coils to open and close the valves. Clearly the electrical and RPM performance required from the this system were not ready or suitable for a F1 engine.
What Renault have is an Electro-hydraulic system, where two pressurised circuits operate the valve (16). Valve return is still handled by the pneumatic system (52, 20), but the opening of the valves discards cams for a hydraulic circuit (50) controlled by a electronic valve (58). As this system can use high pressure hydraulics already on the car to operate the valve at the required RPM ceiling, the system seems almost too simple..! Infinitely variable valve timing plus the loss of the reciprocating weight of the cams and drive gears makes this an enticing solution. This solution has yet to race or to my knowledge even be tested in a car, Renault have admitted that as a broader automotive organisation, that this systems has been tried.
 

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Pretty cool. I think it would be cool if someone developed a system to use exhaust gas to actuate valves, much like exhaust gases are used to operate some semi-automatic rifles (like the AR-15 or AK-47).
 

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why not just use a solenoid and run it all electronically? why complicate it with the hydraulic system? just seems like 1 more thing that can go wrong. i couldn't imagine a hydraulic actuator being able to cycle faster than an electromagnetic actuator
 

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why not just use a solenoid and run it all electronically? why complicate it with the hydraulic system? just seems like 1 more thing that can go wrong. i couldn't imagine a hydraulic actuator being able to cycle faster than an electromagnetic actuator
Doesnt Fiat do that in their "twin air" engine?
 

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nah, the multiair still uses a cam, but it's altered by a hydro-electric oil pressure valve that lets it adjust timing and duration. It's actually very similar to MIVEC, which essentially does the same thing.. I dunno what Fiat's on about suggesting it's some new and fancy design. It's over 50 year old tech that everyone does these days. maybe a little different approach, but the same end result
 

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what have you been reading?
 

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You guys have no idea...

They use camless pneumatic valves to play music :whipping:

Check this out:



;)
 

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You guys have no idea...

They use camless pneumatic valves to play music :whipping:

Check this out:


Viva Alonso by the way ;)
 

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Pretty cool. I think it would be cool if someone developed a system to use exhaust gas to actuate valves, much like exhaust gases are used to operate some semi-automatic rifles (like the AR-15 or AK-47).

Wouldn't that cause the engine to lose power? You couldn't use just exhaust gasses, you'd have to use combustion gasses to open the other set of valves and that would lessen the amount of energy the engine uses for power. That's why a bolt-action rifle or a revolver has (on average) a higher muzzle velocity than a gas blow-back auto or semi-auto.
 

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why not just use a solenoid and run it all electronically? why complicate it with the hydraulic system? just seems like 1 more thing that can go wrong. i couldn't imagine a hydraulic actuator being able to cycle faster than an electromagnetic actuator

It is very difficult to get reliability out of an electrical solenoid actuating at a frequency of 150+ Hz (150 actuations per second when engine is at 18,000 rpms). Now imagine you have this on each valve at 6 valves per cylinder; thats 48 electrical solenoids. 48 solenoids at say ~10 Watts each is 480 watts (!). The heat generated is extremely high as well as the power draw. Thats why air or hydraulic actuated is more feasable.
 

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... electrical solenoid actuating at a frequency of 150+ Hz (150 actuations per second when engine is at 18,000 rpms). Now imagine you have this on each valve at 6 valves per cylinder;
18K RPM seems to be talking about Formula One engines. But where does the six valves come from?

F1 engines have been spec'd by the technical regulations at 4 valves only for at least a decade now.
 

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Wouldn't that cause the engine to lose power? You couldn't use just exhaust gasses, you'd have to use combustion gasses to open the other set of valves and that would lessen the amount of energy the engine uses for power. That's why a bolt-action rifle or a revolver has (on average) a higher muzzle velocity than a gas blow-back auto or semi-auto.
I think you're misunderstanding what I'm saying. However, I'm not an engineer, so I'm not going to get into a debate about it. It just seemed to me that if exhaust gasses could be used to spin a turbine, they could just as easily be used with a regulator to actuate valves. Again, I'm in no way qualified to argue that it could be done. It was just a thought.
 

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^^^

I agree that they could do it, but I think there'd be some energy loss due to it.
 

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There are HUGE differences between [gas operated] rifles and IC engines.

Most every shot in a rifle has the same chamber pressures - within a few percent - and the timing between when the chamber is first pressurized and when the gas pressure is released into the gas pressure cycling system is very consistent.

IC engines, otoh, are significantly different. First off, even at high chamber pressures, the timing varies significantly due to changing engine speeds.

Anf to add to the issue of lowered chamber pressures due to part-throttle and closed-throttle conditions makes using internal pressures a very difficult thing.

Remember that the ROM range of most street engines is 10:1 while the chamber pressure differences over the whole operating range is much higher. Not to mention how long those "peak" pressures exist for.

The idea might work for a stationary, steady load, steady RPM engine. But good luck getting it started.
 

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There are HUGE differences between [gas operated] rifles and IC engines.
orly?

Most every shot in a rifle has the same chamber pressures - within a few percent - and the timing between when the chamber is first pressurized and when the gas pressure is released into the gas pressure cycling system is very consistent.

IC engines, otoh, are significantly different. First off, even at high chamber pressures, the timing varies significantly due to changing engine speeds.

Anf to add to the issue of lowered chamber pressures due to part-throttle and closed-throttle conditions makes using internal pressures a very difficult thing.

Remember that the ROM range of most street engines is 10:1 while the chamber pressure differences over the whole operating range is much higher. Not to mention how long those "peak" pressures exist for.

The idea might work for a stationary, steady load, steady RPM engine. But good luck getting it started.
Like I said, if it were feasible, it would have be be regulated somehow. I'm not talking about free flowing exhaust gasses being channeled into a plenum to move valves. Again, just a thought. I wouldn't be surprised if someone hasn't tried it before, or at the very least, done some extensive research on it.
 
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