Camless combustion engine may improve ICE efficiency
Cargine's camless combustion engine concept
A petrol powered Internal Combustion Engine (ICE) is approx 25-30% energy efficient at the flywheel and around 15% energy efficient at the wheels. There are many losses within the engine itself including friction and waste heat from the combustion process, but Sweden's Cargine Engineering thinks that eliminating the parasitic losses of the camshaft by building a camless engine may help improve energy efficiency. Using pneumatically driven actuators to shoot the valve open the camless engine concept can provide fully variable valve lift and fully variable lift duration without a camshaft in sight.
The system runs on air pressure of 3-16 bar (44-232 psi) and can provide 8mm lift for 5 milliseconds of duration, with a maximum lift of 14mm, and can operate at engine speeds of up to 8000 rpm. The setup consumes 50 percent less space than a conventional DOHC 4-valve layout and reduces mass by 30 percent.
The net power consumption of the air compressor needed to run the system is said to consume less power at low rpm but average out about the same as a camshaft over the entire driving range, consuming more power at high rpm (less than 4kW at 6000 rpm for a 2.0-liter 16-valve four). On a normal driving cycle it consumes less energy than a regular camshaft driven system.
Several development partners have signed on, including supercar-maker Koenigsegg and the Scuderi Group.
It is still a poppet valve system. This system was designed back when they were pumping out mineshafts and the system was driven, not a prime mover. Over a decade ago we had a modern non poppet valve patented in the U.S. It was never picked up by an auto manufacture. Over 60 years ago the idea had been proven in concept. At that time the issues of sealing the compression were insurmountable. The system, which allowed a car to go from walking speed to highway speed without switching gears, was dropped. Incidentally, the system also had the advantage swirling the gas air mixture, of which we have heard so much more recently. So here comes another unnecessary complication paraded as an advance. It still has the time-volume flow problems inherent in poppet valves but not in the rotary valves mentioned above.
Ho-Hum. people go to engineering school for this?
Cargine's technology is still complicated overkill with it\'s own new set of weaknesses. A straightforward resolution is already being manufactured by Coates Internaional Ltd. right here in the USA.
See their Spherical Rotary Valve Cylinderhead: http://www.mostadvancedengine.com/
Honda MotoGP (Bikes) racing have been using pneumatic valves for years, they revved to 19,000 RPM then were restricted if my old mind remembers correctly. I know it is slightly different concept, but only revving to 8k, use no less power, so it's a weight saving of 30% of the cams/heads (say 10KG for avg in line sedan engine). Not much to bring, I DO like it, but think ICEs are just throwing every bit of tech to try and keep them in the race, when they should have never got major share of engines when only 20-35% efficient.
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