Welcome to the next step in engine technology. Camless engines use solenoid valves instead of the conventional camshaft, cams, gears, rocker arms combination. Solenoid valves are driven electronically allowing completely freedom of valve control. A computer controls the opening and closing of the valves instead of cam lobes actuating rocker arms. The abscence of all that mechanical bulk allows for a lighter and more compact valvetrain package. It also means you don’t need a timing belt anymore.
Camless engines have been around for the past 5 years in testing phases and used in competitions but I do not know of any that have been put into production cars yet.
It’s the next logical step from the current variable valve timing and cam profile phasing technologies that try to go around the limitation of a camshaft’s fixed timing properties. With the flexibility of the valve being electronically controlled, you can have maximum torque at all engine revs and the best fuel mileage possible. A racing cam is shaped to optimize engine output at high speeds without regard for the way it roughens up an idle. With camless valvetrains, we don’t have to live with that.
There is a very good explaination on camless engines pros and cons in this issue of Mechanical Engineering Magazine.
Why am I talking about camless engines of all the sudden? Because we could to see it in road cars soon. The 2007 W204 Mercedes Benz C-Class is expected to be the first car from German marque to use a camless engine.
Mercedes calls it the technology KDI EVT. The KDI EVT is supercharged, with direct injection and uses an electronically controlled cam-less valvetrain. KDI EVT is likely to stand for “Kompressor Direct Injection Electronic Valve Train”. Just a wild guess. :P
I believe this could be the first implementation of camless valves in a production car, assuming no one beats them to the 2007 release date.
There are no details on exactly how the engine works, and what exactly is being used to actuate the solenoid valves, but if I get any information I will write about it rightaway. This will definitely be interesting.
Siemens Automotive Camless Engine