Combustion chamber integrity

During the 20th century, combustion chamber shape, cylinder head design and associate technologies have been implicated in main IC engines improvements. To remain compatible with all existing and future strategies and associate technologies, VCR engines must not induce significant changes to these components. Indeed, modern engines can integrate: 4 or 5 valves per cylinder;  1 or 2 spark plugs per cylinder; Possibly, one Direct Injector.

On the other hand, cylinder head design has several consequences on:

		Cylinder filling ability (pumping losses, specific power and torque);
		Internal aerodynamics (fine scale turbulence, flame speed, gases-to-wall heat transfers, tumble, swirl, charge stratification...);
		Flame propagation law (engine efficiency, pollutants generation);
		Flame quenching (HC and CO generation).

All VCR designs based on additional pistons or additional chambers located in the engine head do not conform to an indispensable requirement for future VCR engines: combustion chamber and engine head integrity.

Conclusion

VCR engines have to remain compatible with all existing and future chamber shapes and cylinder head designs.

(see: The MCE-5 technology response to VCR engines combustion chamber requirements)