Here is a new type of 4 stroke engine I have designed. It uses a variable electronic cam that can be used to shut down cylinders not in use. Because the center can be removed, the outside can be built using aluminum or ceramic materail. I haven't built one yet, so I do not know if it would work, so this is mainly a theoretical motor.
It is on a PDF format:
Here it is the NCAM Motor:
More on the design of the No Cam Motor. NCAM2