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While it is true that I have developed a "successful" small engine VVT system with solenoid operated, micro computer controlled, valves I am a long, long way from haveing a control system capable of HCCI.
Controling valves with solenoids has some special challenges that makes applying this type of VVT to automotive engines much more challenging than most realize. Because the cylinder pressure when you want to open the exhaust valve isn't constant, it is very difficult to precisely control valve opening. There is a significant response time for the valve solenoid assemblies. For my small EVIC engines it is in the 2 millisecond range. But it varies with, among other things, cylinder pressure and solenoid temperature. When you try to compensate for these you soon discover that it isn't easy and the control algorithms become very complex. You would like to have temperature, pressure and position sensors. They will be in a very harsh environment so reliability is going to be a challenge. Sure it can be done, but is it going to be more reliable and more cost effective that BMWs Valvetronic system? And is it going to give the precise control that will be needed for HCCI? These are, from my experience, still open questions.
I encourage anyone who thinks it is going to be easy to get my Student Guide CD and use it as a guide to design and build a solenoid operated valve system for a larger engine. When you get it working with automotive reliability you will better understand what I am saying. Dave Bowes, EVIC designer.