Rotational speed

The MCE-5 rotational speed limit is comparable to that of conventional SI engines. Expected key-speeds for MCE-5 are as follows:

		Max torque speed at about 2,000 rpm or lower;
		Max power speed at about 5,500 rpm or higher;
		Limit speed at about 7,000 rpm.

MCE-5 rotational speed limit is not due to the load applied to gears, but to the tensile force applied to the connecting rod: dimensionning parameter for gears is not the tangential stress due to inertia forces (22,000 N at 7,000 rpm), but that due to gases pressure (37,000 N at 0 rpm).

As a result, MCE-5 gears could assume a maximum speed of about 9,000 rpm (threshold beyond which tangential force due to inertia forces is equivalent to that of gases pressure). The rotational speed limit of MCE-5 is due to the connecting rod's resistance to tensile force for 3 main reasons:

	1)	The MCE-5’s moving parts generate inertia forces that are comparable to those of a Diesel engine (at the same speed);
	2)	The MCE-5’s speed limit is not 5,000 rpm like Diesel, but 7,000 rpm.
	3)	As the MCE-5’s crank radius is divided by two compared to that of a conventional engine of equivalent stroke, tensile force applied to the rod is doubled.

For these reasons, the MCE-5 connecting rod has to assume high tensile forces. On the first generation prototype, the rod has been widely oversized to avoid any unexpected problem resulting from this conventional component:

MCE-5 next generation prototype will integrate a lighter and optimized connecting rod.

(see: VCR engines’ requirements for mass-production: rotational speed)