The irony here is that camless engines are relatively easy to build. The average hacker could modify a small four-stroke engine for camless. The latest to catch my attention: engine valves that operate without camshafts. For decades the idea of electronically controlled electromagnetic. The “camless” engine developed by Koenigsegg sister company FreeValve edged closer to production on Friday with Qoros’ unveiling of a.
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Wait long enough, and Moore’s Law of increased computing power in smaller packages or just good ol’ human ingenuity eventually makes all great ideas practical. The latest to catch my attention: For decades the idea of electronically controlled electromagnetic, hydraulic, or pneumatic valve actuation has been studied, developed, and ultimately abandoned by big-name engineering firms such as Lotus and Ricardo—as well as familiar automakers including BMWFiat, FordGM, and Renault.
Now a spinoff of hypercar maker Koenigsegg called Freevalve appears poised to bring the concept to production. Freevalve seems to be taking an all-of-the-above approach with its so-called pneumatic-hydraulic-electronic actuators.
Where are all the Camless Engines?
But air does the work. The team first employed this solution on the Scuderi Split-Cycle air-hybrid engine I first covered in June That design demanded valves that opened far more quickly than a traditional cam-driven design could manage.
Because the engine cammless braking energy as compressed air, that energy source was abundantly available. So compressed air opens the valve almost instantly, electronically controlled hydraulic pressure holds it open, a coil spring closes it, and passive hydraulic pressure cushions its “landing. The first thing everybody frets about with such systems or with an old car overdue for a new timing belt is what happens if the valves go out of sync and try to stay open when the piston is rising.
Actually, not much, explains Freevalve marketing director Andreas M ller: Sure, if the valves are inclined at a steep angle, the piston could bend a valve and cause some mayhem.
But M ller notes that “a combustion chamber designed from scratch with the Freevalve system is likely to have a higher compression ratio [allowing valve timing to reduce effective compression] and a smaller area-to-volume ratio with more upright valves that are less prone to bending in case of piston contact. The second major concern is the one that generally doomed these systems in the past: M ller says that although the compressor featuring standard AC-compressor innards capable of peak pressures near psi generally consumes more energy than camshafts, this is partially offset by a reduction of the engine oil flow and pressure required to lubricate cams and valves.
Freevalve’s head employs a dedicated hydraulic circuit.
Video shows inner workings of Koenigsegg’s camless engine
And Freevalve’s high-speed friction penalty is countered by the fact that at idle and lower speeds its parasitic losses undercut those of several VVT systems. These route the flow from half the exhaust valves to the turbo while the rest enginne it, eliminating the need for a turbo wastegate. Bypassing the turbo at startup heats the main catalyst quickly enough to eliminate a close-coupled cat. DEP also improves scavenging of residual exhaust. As installed on a Chinese Qoros 1. Perhaps more important, the engine’s power improved by 45 percent, torque by 47 percent, and fuel consumption by about 14 percent at steady highway speeds.
Official fuel consumption is expected to mirror that of a similar diesel but at lower incremental cost. Development of Qoros’ “Qamfree” engine should conclude late this year with production following shortly thereafter.
Another 15 manufacturers have expressed interest in the concept. Every such efficiency-boosting miracle like this further delays the demise of the combustion engine.
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