Prototype stage

A new type of combustion engine dubbed the Merritt Unthrottled Spark Ignition Combustion, or MUSIC, has now reached the industrial prototype stage.

Dr Dan Merritt and his team at Coventry University have spent five years developing the current technology and have now produced a single cylinder prototype to demonstrate the benefit of the new design.

The past 18 months of the project have been run in collaboration with an industrial development partner, Powertrain Technologies Limited (Ptech) in Norfolk with part funding from the UK Department for Transport.

This phase has seen significant advances made including the design of a prototype 4-cylinder engine by Ptech which is now on a test bed.

The key benefit of the MUSIC system is significant improvement in thermal efficiency at low speed low load. This puts the gasoline engine in the realms of diesel equivalents as far as CO2 emissions are concerned.

At the heart of the system is a patented indirect combustion chamber that uses helical swirl to generate effective stratification of the fuel spray and allows the engine to run completely unthrottled. The first prototype engines will be followed shortly by an in-car demonstrator.

The map shows lines of constant fuel usage (in g/kW.hr). In typical use, a vehicle will spend 80 per cent of its time in the region towards the botom left of the map. In this region, the engine is heavily throttled and the economy is significantly degraded due to the pumping losses incurred and poor thermal efficiency. The MUSIC engine is at its most effective in this region by reducing the pumping loss and improving the thermal efficiency.

In a shift from its normal independent consultancy role, Knibb, Gormezano and Partners has agreed to provide its expertise to assist with the commercialisation of the new technology. This will require investment in future steps of development leading to licensing the technology to the auto industry.

Brian Knibb, KGP’s managing director, said: ‘The MUSIC system offers a relatively low cost route to achieving substantial improvements in fuel consumption for gasoline engined vehicles; unlike many of the complex systems already coming to market it has no moving parts and uses regular componentry.’