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gbdolfans

Engine with no cam!!

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Hey all, what do you think of this.Kind of cool!!:D

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Interesting, but "camless" valve actuation has been around for a long time, and prototype systems have used hydraulic, pneumatic and electromagnetic control of the actual valve operation, with a microprocessor running the whole show.

There are already large industrial and ship diesels using this technology, but for cars, it's a lot of complexity for a relatively small increase in performance / efficiency.

Wanna build your own? Here's a brief overview.   B)

http://hackaday.com/2016/02/16/where-are-all-the-camless-engines/

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Excellent.

Then there are rotary valves too:

(from Wikipee)

"The rotary valve combustion engine possesses several significant advantages over the conventional assemblies, including significantly higher compression ratios and rpm, meaning more power, a much more compact and light-weight cylinder head, and reduced complexity, meaning higher reliability and lower cost. As inlet and exhaust are usually combined special attention should be given to valve cooling to avoid engine knocking.

Rotary valves have been used in several different engine designs. In Britain, the National Engine Company Ltd advertised its rotary valve engine for use in early aircraft, at a time when poppet valves were prone to failure by sticking or burning.[1]

From the 1930s, Frank Aspin developed a design with a rotary valve that rotated on the same axis as the cylinder bore, but with limited success.[2]

Kawasaki and others have also used rotary valves in two-stroke motorcycle engines, where the arrangement helps to prevent reverse flow back into the intake port during the compression stroke.[3]

Austrian engine manufacturer Rotax used rotary intake valves in their now out-of-production 64 hp (48 kW) Rotax 532 two-stroke engine design and continues to use rotary intake valves in the 532's successor, the current-production 64 hp (48 kW) Rotax 582.[4][5]

US company Coates International Ltd has developed a spherical rotary valve for internal combustion engines which replaces the poppet valve system. This particular design is four-stroke, with the rotary valves operated by overhead shafts in lieu of overhead camshafts (i.e. in line with a bank of cylinders). The first sale of such an engine was part of anatural gas engine-generator.[6]

Rotary valves are potentially highly suitable for high-revving engines, such as those used in racing sportscars and F1 racing cars, on which traditional poppet valves with springs can fail due to valve float and spring resonance and where the desmodromic valve gear is too heavy, large in size and too complex to time and design properly. Rotary valves could allow for a more compact and lightweight cylinder head design. They rotate at half engine speed and lack the inertia forces of reciprocating valve mechanisms. This allows for higher engine speeds, offering approximately perhaps 10% more power. The 1980s MGN W12 F1 engine used rotary valves but never raced. Between 2002 and 2004 the Australian developer Bishop Innovation and Mercedes-Ilmor tested rotary valves for a F1 V10 engine.[7]

Bishop Innovations' patent for the rotary valve engine was bought out by BRV Pty Ltd, owned by Tony Wallis, one of the valves original designers. BRV has constructed several functional motors using the rotary valve technology, such as a Honda CRF 450, which had greater torque at both low(17% increase) and high (9% increase) engine speeds, and also produced more brake horsepower up to around 30% more at functional engine speeds.[7] The engine was also considerably smaller and lighter, as the cylinder head assembly was not as large.

A company in the UK called Roton Engine Developments made some progress in 2005 with a 2 rotor (one for inlet and one for exhaust) on a motorcycle single cylinder Husaberg. They filed patents and got an example running in 2006 but were backed by MG Rover who subsequently went bust, leaving Roton without enough funds to continue. The designs surfaced some years later in Australia with Engine Developments Australia Pty Ltd. A prototype casting was produced in 2013 on a Kawasaki Ninja 300 parallel twin unit. This unit is still in development phase at the time of writing but is significant as it has the potential to run much higher compression ratios than even other rotary valve engines due to a significant but undisclosed new cooling method of the combustion chamber and the ability to eliminate the throttle completely, making it vastly more economical at lower engine speeds, so it is claimed."

 

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Several manufacturers have went away from the "conventional" valve setups, with some success. I own a ducati 999, which has desmodromic valves. It eliminates valve float, and makes a little more power, but its hard to beat the cam/lifter/pushrod/rocker arm/valve setup. The old stuff runs forever. This newer technologically advanced stuff doesnt seem to last as long, and costs a bunch more to fix when it breaks. But I guess thats the point.

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Several manufacturers have went away from the "conventional" valve setups, with some success. I own a ducati 999, which has desmodromic valves. It eliminates valve float, and makes a little more power, but its hard to beat the cam/lifter/pushrod/rocker arm/valve setup. The old stuff runs forever. This newer technologically advanced stuff doesnt seem to last as long, and costs a bunch more to fix when it breaks. But I guess thats the point.

:D Yup.

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2-stroke engines have been running without conventional valves for probably 100 years. Cars, motorcycles, lawnmowers, chainsaws, etc. . . :D

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2-stroke engines have been running without conventional valves for probably 100 years. Cars, motorcycles, lawnmowers, chainsaws, etc. . . :D

Actually, I believe that at least one of the very first automobile engines was a 2-cycle.

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