Has anyone ever though about why no one has cam out with an engine that has inlet and exhaust valves being controlled by solenoids which are opened and closed by the ecu just like injectors are... this would completely eliminate the need for a camshaft and would have less friction and load on the engine which means more power to the wheels and the engine would be more efficient... would also mean valve timing, could be controlled completely by electronics which means the valve timing could change as the revs increase just like ignition timing, which means you have maximum power at every rev range you need... and can be all done by tuning the ecu... just wondering if anyone else has thought of this coz ive been thinking about it for a while now... anyone that has an opinion please feel free to discuss cheers
cos its expensive and unreliable.... electronic parts are not the best thing to use for heavy duty applications. it takes a fair bit of force to open a valve under load so the solenoid would be massive and bulky and need alot of power to work efficiently....
And with how often they have to be used they wouldnt last too long when compared with a mechanical valve train
I think Fiat are trying to produce the first solenoid production engine, lets just say that the technology is coming, its just under development. It will be a massive leap forward in engine efficiency, power and reliability, it will probably be the biggest upgrade since Ford introduced the cylinder block with the model T.
I started thinking about this maybe 5 years ago? it's already patented etc. apparently some F1 cars used this technology? but maybe the actual solenoids were hydraulic with electric flow control or something like that? anyway, mercedes is going to release this (or already has) and it's called 'KDI EVT' (electronic valvetrain, supercharged, direct injection motor) few more years and hopefully it will be a bit more common and they'll have a lot of the bugs sussed out. brilliant idea
thats F1 technology, there are a few variations on it, i think most F1 cars run either a pneumatic or hydraulic based valve train.
oh damn... i thought i was the first to think of it! haha.. would be good to see this come out in a production car =]
I think that valves in F1 are still opened using mechanisms based around cams. They have used pneumatic (air?) springs to close them for a while though - I think that Renault were the first to do so. I believe that Lotus has been playing a system also. Probably of more benefit (vs cost) as a development tool where any number of 'cam' profiles could be tried without the cost and time required in machining and installing many different camshafts. I think that Siemens? looked at using lifters that partially collapsed, much like those being collapsed completely in DOD and AFM systems currently, to achieve lower cam lift and shorter duration too. That would probably be some way down the same track.
