electrical valvetrain

[RobWard]

I've just been reading "The Engineer" magazine in which there is an article about rotary valves by Coates and Roton.
I remember reading the threads about the Coates valves, and how people weren't impressed by the claims, but it got me to thinking about variable valve timing, and I wondered if anyone had tried an electrically powered valve train.
I can see it offering a fairly simple way of altering timing, but would the energy losses in running a large alternator outweigh the gains in timing and directly powering the valve train.

Apologies if this has been covered before, but I couldn't find it in a thread search.

(I should also make clear that my practical engine experience is limited pretty much to completely rebuilding my landrover engine when it seized, but I do enjoy reading this forum...)

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[Romefu12]

RobWard;

I was a witness to the results of testing of an all-electrical valve train installed on an experimental diesel engine in the Detroit Diesel Engine factory in Detroit Michigan back in the winter of 1995. I was at the factory school to obtain my Detroit series 92 and 149 engine certifications. I have to say that the experimental engine was in fact in very bad shape because they had just completed a test in which the electrical power was interrupted to the valve train and a backup system was to take over instantaneously while in operation. The test was a failure because of their inability at that time to provide a formidable backup to the interrupted valve train power. This problem may have been overcome since that time however I really never heard anything of the program again. They have a great facility up there in Detroit and I fully recommend factory training to all the automotive heads out there.

 

[EdDanzer]

We have experimented with an electric over hydraulic valve control some. This should be more robust and less expensive to build. Unlike some systems that use engine oil pressure, we use high pressure hydraulic oil. The thing we have not been able to determine yet is how high of rpm is practical
This web site has information:

http://www.fev.com/index3.htm

 

[SBBlue]

Caterpillar has introduced their ACERTS engines designed to minimize diesel engine emissions. They claim to used "electrohydraulic actuators" for variable valve timing.

There is considerable advantage to having variable valve capability. "Internal EGR" can be accomplished in this manner, and the system can function as a "Miller Cycle" -- where the piston compression ratio is less than the piston expansion ratio.

As far as I can tell, the Caterpillar valves sound similar to what EdDanzer describes above. I suspect they use the valves for both internal EGR and Miller cycle operation.