Quasi-Constant Volume (QCV) Spark Ignition Combustion @derbyuni

 We’re revisiting the huge amount of unanalysed data which we generated on this project thanks to @profJillStewart. and hoping to be publishing again on this subject in the near future.

Hybrid Vehicle Zero Constraint Free Piston Energy Converter: EPSRC Grant: GR/S97507/01

Collaborating University: Dept. Aeronautical and Automotive Engineering, University of Loughborough UK.Collaborating Company: Lotus Engineering. Consortium Project Manager: Paul Stewart

The technology is based around a single-cylinder free-piston internal combustion engine (ICE), which is run on a 4-stroke cycle, with an integral linear electromagnetic machine and electromagnetically operated poppet valves.


Chen, Rui & Winward, Edward & Stewart, Paul & Taylor, B.P. & Gladwin, Daniel. (2009).

Quasi-Constant Volume (QCV) Spark Ignition Combustion. SAE Technical Papers. 10.4271/2009-01-0700.

The Otto cycle delivers theoretical maximum thermal efficiency. The traditional design of internal combustion engines using a simple slide-crank mechanism gives no time for a constant volume combustion which significantly reduces the cycle efficiency. In this study, using a high torque, high bandwidth, permanent magnet electric drive system attached to the crankshaft, variable angular velocities of the engine crankshaft were implemented. The system enabled reductions in piston velocity around the top dead centre region to a fraction of its value at constant crankshaft angular velocity typical in conventional engines. A quasi-constant volume combustion has thus been successfully achieved, leading to improvements in engine fuel consumption and power output which are discussed in detail.

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