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

Cylinder head

The MCE‑5 VCRi cylinder head is not overly innovative. It both covers the combustion cylinders and the VCR actuators cylinders and is therefore subjected to forces twice as high as a conventional cylinder head is. It has 15 screws instead of 10.

Multi-layer steel (MLS) is used to guarantee
leak tightness between the cylinder head
and the crankcase

The part that covers the VCR actuators is not cooled and comprises the intakes. This configuration avoids having the exhaust gases heat up the VCR actuators. On current prototypes, the GDI injectors are placed on the side at a 22.5° incline, and so are also housed above the VCR actuators. The part of the cylinder head that covers the VCR actuator cylinders is of course rigid since these cylinders are smaller than combustion cylinders (63 mm instead of 75) and don’t comprise water jackets, valves, spark plugs or injectors.

The sealing between the cylinder head and the crankcase is made by a multi-layer steel (MLS) head gasket whose “VCR control” part received special adjustments to manage high oil pressure. This gasket operates under the normal conditions for conventional engines.

The MCE‑5 VCRi GDI cylinder head is equipped
with an injector oriented at 22.5°
and with a valve angle of 15°

The MCE‑5 VCRi cylinder head gasket provides
the required leak tightness to both the combustion
cylinders and VCR actuation cylinders

MCE‑5 VCRi 1.5L MPFI cylinder head (left) beside
the EP6 1.6L BMW - PSA cylinder head (right), in 2008

The main characteristics of the MCE‑5 VCRi cylinder head