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 cam, or camshaft, is a long rod with lumps on it which turns at half of the speed of the engine. The lumps, or lobes, each press on a valve at the top of the .
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Hundreds of millions of cycles mechanically and electrically with enough spring force to close the needle valve enough to be liquid tight at 30 to 40 psi fuel rail pressure. The computer is able to sense when not all of the fuel is being consumed and immediately relax valve timings to supply less fuel to a cylinder.
I still trust that a well designed system will work. However they may still be cam actuated. I barely understand why the people still like to watch it. And fuel injectors run for years without failure. It is quite challenging to seal a rotor that sees vastly different temperatures. Camless engines are able to produce less emissions than their equivalent camshaft counterparts because they are able to more precisely control the combustion procedure, allowing for more complete combustion of all hydrocarbons.
While these systems do work, they tend to be mechanically complex, and expensive to repair. Its not CO, its not much NOx, but because you can see it as black smoke, the uneducated think that is bad stuff that is killing baby sea-lions.
Slides, rotary valves, everything is on the table. Lobes on the shaft press on tappets which then move the valve stems and the valves themselves. I was in a club at my local community college back in We were talking about trying this kind of thing and even drew up a few plans, but as all things go life got in our way and it never happened.
The fact is that this is an area where the returns diminish very quickly and thus economically there are only a very few applications where they will ever be practical and those are being exploited. With a cammed setup, you have two metal objects smacking into each other, with nowhere else to go.
Instead, I had 30 seconds of inconvenience. To meet thees standards the mass of the vehicle must be reduced as much as possible. Why not just replace the camshaft with really teeny weeny two stroke engines driving the valves? I heard they are very smooth when accelerating.
Note that this project uses two solenoids — one to open and one to close the valve. Christian Koenigsegg also claims that the PHEA camless technology allows the elimination of the pre-catalytic converter, because the standard catalytic converter can be brought up to temperature quickly by manipulating the exhaust cycle. Which leads to thicker wires, massive transistors with massive heatsinks and massive EMI. When I was child 70ties I think there were only general rules like engine displacement and measures of the car.
This would mean eliminating the camshaft, timing belt, and most of the associated hardware. Lots of physical reasons for this not being true. The rotary I saw run was a Detroit Diesel 2 stroke converted to a four stroke, custom head, with a rotary valve running on a belt, A bar with a slot in it turboed, and it screamed.
There is still a need for automotive ICEs, although if you go to full series hybrid then all the complications associated with variable loading and speeds can be tossed out in favour of a fixed-speed, fixed load motor-generator driving a battery pack. Throw in the tolerances of electromechanical components, and you either need hella precise parts or a good tuning procedure to tune out variations….
Conventional light bulbs are relatively simple devices- a bit of glass formed in one simple step, a bit of filament and a conductive metal cap… CCFLS? I would love to see a camless engine myself but no system is flawless. Forces would be far greater working a valve by at least an order of magnitude.
Both these have been done with mechanical systems but seems would be far simpler with software and some valves. That is the main reason why these engines were no widely deployed — the reliability is simply not there and the purely mechanical systems are cheap and work well enough for most situations.
Camless engines have been around for a long time. If you are conservative, you need 2 solenoids per cylinder, but on a modern multi-valve engine, cxmless might need 4 or more, since you might not want to open both intake or exhaust valves camlesss the precisely the same time.
The engine control unit ECU fires the injectors at just the right time to inject fuel into the cylinders. Cakless engines can further reduce NOx emissions with the use of fuel staging. On a camless, the piston would hit the valve and be pressing against the force of the actuator.
Where are all the Camless Engines?
I knew the design of modern IC engines was pretty-well worked out. It also allows multiple lift events per cycle and, indeed, no events per cycle—switching off the cylinder entirely.
Common problems with camless engines include accuracy at high engine speeds, temperature sensitivity, increased weight, packaging, high noise, high cost, and unsafe operation from electrical problems. Actually no regulation comes without the approval of at least some of the industry players.
Camless piston engine – Wikipedia
Hmm… Speaking before thinking… I suppose the combustion-pressure would be too much to hold with such a valve configuration. 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.
Pneumatic or hydraulic activated valves would be the way to go. Um… cars already have electronics. Engine manufacturers have spent years working around the limitations of the camshaft. This would also eliminate some of the other rpm limitations and accuracy shortcomings inherent in the reciprocating valve system. So, in the end, VW decided to beat the feds at their own game, when the test parameters we detected the engine ran in a limp-noodle mode, one you would never buy as a consumer but passed the tests.
Is the Era of the Camless Valvetrain Finally Upon us?- Technologue
A multi-cylinder gasoline engine is a complex dance. With a camless engine, fuel injection and exhaust timing are directly controlled by an engine control unit and can be constantly changed and adjusted without stopping the engine.
Every such efficiency-boosting miracle like this further delays the demise of the combustion engine. If you want an A next time then maybe you should proof-read your work before handing it in.