MUSIC - The most important breakthrough in I.C. Engine combustion since the invention of diesel engine.
MUSIC is a new gasoline engine invention. Capable of greatly improving fuel economy at part load, particularly in urban driving. It is a cylinder head modification, which operates unthrottled like a diesel, delivering fuel efficiency similar to the diesel engine. It has progressed from a 5-year university research project to a 4-cylinder engine produced at Powertrain Technologies Ltd (Ptech). It is currently being optimised by Ptech Ltd. in the UK.
Music has an advantage over diesel engines because it is able to allow treatment of NOx exhaust emissions with conventional catalytic converters. In Music NOx is only produced in unacceptable quantities at high engine loads and MUSIC can be made to operate stoichiometrically at such high loads by partial throttling at the high end of the load spectrum.
WEB SITE UPDATE, 14th November 2008
Measured MUSIC Thermal Efficiency exceeds modern diesel engine performance
The outstanding thermal efficiency results for the MUSIC engine were obtained at Tickford who tested the MUSIC engine designed and built by Powertrain Technologies Ltd at the end of their Energy Saving Trust funded project to construct a MUSIC engine cylinder head and fit it to a Ford Mondeo four cylinder block. These results have now been compared with recently obtained performance results from a modern diesel engine. We do not have details on the exact construction of this diesel or indeed on the parasitic loads which were included in the evaluation of its thermal efficiency but we are confident that engine specialists in the motor industry will be able to compare these diesel results with their own experience. The four cylinder MUSIC engine tested was driving its own GDI fuel pump and its oil pump but was not driving its water pump, alternator or fan. Dr Merritt was asked to explain the reasons which could allow the MUSIC engine to exceed the BTE of the diesel engine, as the results shown below indicate as both engine types operate completely unthrottled and therefore enjoy the full benefits of lean-burn at part load. He gave the following reasons:
- Below BMEP loads of some 7bar all the fuel burnt in MUSIC is contained and is fully burnt only within the external combustion chamber which exposes a much smaller surface area to the flame, some 40% compared with the direct diesel engine.
- MUSIC combustion rates can be much faster than diesel, the gasoline is vaporised when ignited and the stratified primary zone is stoiciometric when ignited by a spark. Faster combustion avoids burning during the expansion stroke which is very penalising for thermal efficiency.
- The MUSIC engine tested has two valves per cylinder, a lower friction load and lower fuel pump parasitic load.
MUSIC DATA TAKEN INDEPENDENTLY BY TICKFORD (U.K.) IN APRIL 2008, USING THE MUSIC ENGINE DEVELOPED BY POWERTRAIN TECHNOLOGIES LTD , SNETTERTON U.K, AT THE END OF AN ENERGY SAVING TRUST FUNDED PROJECT.
MUSIC tested was a 2.0 litre, 8-valve engine, based on a Ford Mondeo crankcase. Diesel engine was a 2.4 litre direct engine whose results were provided, in confidence, by a reputable engine R&D company. The BMEP conditions at which the diesel results were taken only approximate to those of Music’s.
Re-evaluation of MUSIC’s fuel injection modes
MUSIC is now expected to operate with simple solenoid GDI injectors, at moderate fuel line pressure and without pulsing to meet lower loads and speeds. Further studies were carried on how to meet the full load/speed range of the MUSIC engine. The requirements from MUSIC in this respect are much less severe than that of the diesel engine which needs to accommodate a fuel flow rate variation of some 50:1 from idling to full load full speed. Diesel meet this requirement by using very high fuel line pressure to meet maximum demand (over 2000bar) as well as pulsing the delivery to meet lower demands. Early studies, reported in the Coventry University seminar in February 2008, suggested that MUSIC may also need to pulse the delivery of its injectors to meet lower demands even though it uses relatively low fuel line pressure (below 200bar). It is now realised that pulsing will not be necessary. It is expected that the economy injector will be able to meet loads up to 7 bar with the power injector topping up with short durations from 5bar onwards. At higher BMEP demands the power injector will control load by increasing injection duration and advancing the injection starts with increasing engine speeds and loads.
The recent patent application PCT/GB2008/002060 has now undergone a search and the written opinion accompanying the search report states the claims to be novel, inventive and patentable.
WEB SITE UPDATE, 18th JUNE 2008
- The single cylinder research MUSIC engine prototype at Coventry University was tested using pure Methanol and pure Ethanol to investigate compatibility with bio fuels. The engine operated successfully with both fuels without modifications from its gasoline layout.
- Patent update: Subsequent to its grant in the USA earlier on, Patent publication number WO 2005/052335, was recently granted in the European Patent Office and is now being filed in individuals countries in the EEC.
- Patent publication number WO 2007/080366, was recently granted in the USA and accepted in the European Patent Office.
- A new patent application PCT/GB2008/002060 was filed in June 2008.
Reasons for very high Brake Thermal Efficiency of MUSIC:
(*marks possible improvement potential over DI diesels)
- Low heat loss due to lower gas temperature in lean burn.
- *Low heat loss due to small surface area of CC, which has much smaller surface/volume area ratio compared with DI engines (40% compared with DI).
- *Fast combustion due to high swirl ratio when chosen, hence constant volume cycle with highest thermal efficiency.
- *During compression stroke highly swirling air recovers heat from CC surface, such heat helps evaporate fuel.
- *During combustion gases expand radially inwardly away from CC surface, avoiding contact between burning gases and CC walls.
- *Fast combustion and lean-burn avoid NOx formation over most of part load, an endothermic process.
- *Complete combustion of pre-vaporised fuel in excess air avoids HC and CO emissions.
- Lack of induction pumping loss resulting from throttling at part load.
(note: these do not affect most of the part load operational range encountered in urban driving, the reduction is confined to high engine speed and load)
- Pumping losses through orifice, low due to large orifice but expected to become progressively important at engine speeds above 5000rpm. However, kinetic energy imparted to air is retained as heat in CC reducing fuel demand in the CC.
- Above 95% of load ratio when MUSIC combustion takes place also above piston, surface area heat loss increases by up to 30%.
High load is achieved with fuel injected by the second injector (power injector). This injection takes place during the last 30 degrees of the compression stroke, during the period when the fuel injected earlier by the first injector (economy injector) is burning already. Part of the power injector fuel enters the bump clearance above the piston. The fuel so injected burns at it mixes with air soon after injection similar to the burning process in diesel combustion. Hence there is no long flame path. The mixing process is induced by the flow of hot gases from the chamber into the cylinder’s bump clearance.
Low load combustion in MUSIC
Using the economy injector on its own, the start of fuel injection is chosen to coincide with the moment when air mass flow rate is 15 times that of the fuel flow rate from the injector, ensuring a stoiciometric mixture. If the injection continues the mixture so formed will become lean. However the spark plug will be presented with a stoiciometric mixture for ignition under all conditions and when this primary zone burns it will ignite the lean mixture which is situated behind it in the CC. As far as we know MUSIC is the only combustion system now operating, capable of ensuring exact stoiciometric mixture at the spark plug, for stratified charge combustion. Such low load operation can be used up to BMEP values of some 5 to 6 bar. When increased output is needed the second, power injector, is used to top up the fuel supply.
More details on fuelling strategy can be seen in the Invention Section, downloading the seminar presentation.
PRESS RELEASE MAY 2008
MUSIC ENGINE PRODUCES A FUEL EFFICIENCY IMPROVEMENT OF 20% ON ITS FIRST FOUR CYLINDER TEST EVALUATION.
A new British engine technology offers an answer to the rapidly escalating price of fuel. The Merritt Unthrottled Spark Ignition Combustion (or MUSIC) engine, initially developed at Coventry University has, for the first time, undergone formal evaluation tests in a four cylinder form developed by Powertrain Technologies Ltd near Norwich with the aid of a grant from the Energy Saving Trust. This petrol engine is able to operate unthrottled, like a diesel engine, and can come close to achieving the fuel efficiency advantages of the diesel engine.
In tests conducted recently at an independent test facility, as required by the grant providers for the project conclusion, the four cylinder engine achieved a remarkable 19.8% improvement in fuel economy averaged over a conventional petrol engine chosen as a base line target.
The comparison is made against a current Ford 2.0lt Duratec engine as fitted to the Mondeo car. The 20% improvement was calculated over a number of test points simulating an urban drive cycle, known as the NEDC. The thermal efficiency increases as the engine load decreases and at near idling condition the fuel saving measured was an impressive 42.5%.
Andrew Barnes, the Managing Director of Powertrain Technologies, is confident that, in view of these results obtained at such an early stage of development, still more improvements, maybe up to 25%, can be achieved in the near future. He commented “Due to difficulties in obtaining suitable injection equipment we were unable to optimise the engine at certain test conditions, we are confident that there are a few more percentage points available when optimised”.
The four cylinder prototype is based on a cylinder head mounted on a Ford Duratec crankcase and, unlike competing technologies, the MUSIC system does not require any new supporting technology. Apart from the MUSIC cylinder head designed to promote the new combustion system invented by Dr Merritt, the 4 cylinder prototype engine uses currently available production components throughout.
Dr Dan Merritt, believes that the thermodynamic advantages of his combustion system are amply demonstrated in the fuel economy attained by the diesel engine and is pleased that the concept was engineered into a simple working engine to demonstrate this point. The preliminary work at Coventry University, conducted on a single cylinder research engine, enabled the important parameters to be defined and the invention to be patented.
Specific fuel consumption details can be found under the section Engineering.
