Compression Ratio control

The MCE-5 VCR engine block responds to all requested features for Compression Ratio control of future VCR engines: 1) A wide range and continuous Compression Ratio control from 7:1 to 20:1; 2) A high reactivity CR control (100ms and lower to move from CR max to CR min); 3) A cylinder per cylinder Compression Ratio adjustment; 4) A high precision control (about 0.01 mm); 5) A low energy consuming actuation.

The effectiveness of MCE-5 Compression Ratio actuators partly comes from an exclusive technical approach: control jacks use engine inertia forces and gases pressure forces to move from one position to another. Two valves are maintained open or closed by a control stick to transfer oil from the upper chamber to the lower chamber of the jack or inversely (to move upwards or downwards), making the MCE-5 actuators operating as hydraulic ratchets.

As a result, the energy consumption induced by the MCE-5 Compression Ratio control is reduced to a minimum. In addition, MCE-5 control jacks assume all required functions for:

	a)	Keeping the current Compression Ratio whatever the operating conditions;
	b)	Slowing down when reaching the targeted position to avoid shocks and noise emissions;
	c)	Automatically compensating for possible oil leaks to maintain the requested position;
	d)	Protecting MCE-5 gear teeth against overload (by-pass).

The MCE-5 hydraulic actuators do not require electrohydraulic valves or any fragile devices that are temperature or vibrations sensitive. The Compression Ratio position is automatically maintained even if the electric motor is out of order.

As they operate as ball joints, the pistons of MCE-5 actuators also have a major role to provide the best contact distribution on the entire surface of gear wheel and racks teeth.

(see: VCR engines’ requirements for mass-production: Compression Ratio control)