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There is an opinion that all carmakers share: Variable Compression Ratio (VCR) is the most efficient solution to reduce SI engines Fuel Consumption while opening the way to several strategies for the future.

Indeed, VCR is the ultimate tool to reduce Fuel Consumption of Spark Ignition engines while conforming to most stringent emissions standards and automotive market demands. In the near-future, Variable Compression Ratio will be as indispensable for SI engines as multiple Direct injections for Diesel engines.

But all carmakers don’t share the same opinion - for the time being - concerning the point of planning VCR engines production for the near-future. Indeed, several prototypes of VCR engines and vehicles have been developed and tested. If these prototypes confirmed the gains provided by VCR, they also revealed the difficulty to design VCR engines which respond to mass-production requirements (functionalities, reliability, durability, cost).

In this context, next step is to identify and study a VCR mechanism that conforms to VCR engines’ mass production requirements. This design will have to make the most of know-how related to conventional engines while presenting a high reliability, durability and reasonable production costs.

This is the purpose of the MCE-5 VCR engine block which is intended to replace conventional Fixed Compression Ratio engine blocks.

Based on the combination between a rod-crank mechanism and long-life gears, the MCE-5 is an all-in-one VCR technology integrating both power transmission and Compression Ratio control. Its conservative combustion chamber and its totally conventional and invariable piston kinematics allow making the most of know-how related to combustion and performance control. The MCE-5 wide Compression Ratio control range (from 7:1 to 20:1) permits serving all VCR strategies with no limitation.

Thanks to its long-life gears and its roller-guided piston which is no longer subjected to radial stress and piston slap, the MCE-5 guarantees a high durability, robustness and reliability to high-loaded VCR engines. The rigid MCE-5 VCR engine block integrates a rigid crankshaft to ensure a high reliablity and a long lifespan to hydrodynamic bearings.

The MCE-5 VCR engine block has no impact on other engine parts or vehicle components and needs no additional component for connection to gearbox, pipes and peripherals or to fix it into all vehicles. Thanks to MCE-5 reasonable production costs, future engines based on the couple VCR strategy - MCE-5 technology could provide to automotive industry a wide range of efficient strategies to produce fuel-efficient, powerfull and attractive cars which conform to most stringent emissions standards.

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