MCE-5 VCRi: Pushing back the fuel consumption reduction limits

Crankshaft

The MCE‑5 crankshaft has half the crank radius of a conventional engine crankshaft with the same piston stroke. As a result, with the same bore and in-cylinder pressure, the MCE‑5 crankshaft is twice as loaded as the crankshaft of a conventional gasoline engine.

The MCE‑5 VCRi crankshaft has a crank radius half
that of a conventional engine with
the same piston stroke

The crank radius of the MCE‑5 crankshaft is reduced by half and the overlap between the crank pin and main journals is increased. This made it possible to eliminate the crankshaft counterweights without increasing its average bending. The MCE‑5 crankshaft is supported by a particularly rigid bearing line situated in the crankcase. This rigid crankshaft-crankcase assembly ensures a long service life for the MCE‑5 VCRi engine, despite the extremely high loads that it is subjected to. The maximum stresses applied to the MCE‑5 crankshaft and the resulting safety factors remain “consensual” and compliant with industry standards. The elimination of the MCE‑5 crankshaft counterweights leads to an engine length that is identical to that of a conventional engine with the same number of cylinders and the same bore.

Working in conditions close to those of a highly loaded Diesel car engine, the manufacturing and the operating environment of the MCE‑5 VCRi crankshaft are comparable: it is forged and supported by high-pressure bearings. The forging of the MCE‑5 VCRi crankshaft is made easier by its small size and the elimination of the counterweights, which require the displacement of forged material far away from the center of gravity. The MCE‑5 VCRi crankshaft is 30 to 35% lighter than the crankshaft of a conventional engine with the same cubic capacity.

Because of its high natural rigidity (big bearings overlap), the MCE‑5 VCRi crankshaft
no longer requires counterweights

Because it is compact and has no counterweights, the MCE‑5 VCRi crankshaft is
30 to 35% lighter than a conventional engine crankshaft

The main characteristics of the MCE‑5 VCRi VCR crankshaft