Green Car Congress reports on a recent test of the Merritt Unthrottled Spark Ignition Combustion (MUSIC) engine by Powertrain Technologies. "MUSIC is an un-throttled, high thermal efficiency, lean-burn, spark ignition system that uses an indirect combustion chamber to produce charge stratification by means of controlled air management" the unelected reporters reveal. In laypersons terms, a trick cylinder head with an external combustion chamber and twin injectors were fitted to a 2.0 Ford Duratec engine, allowing more efficient fuel-air mixtures and (diesel-like) unthrottled operation from idle to full load. There's no sense in trying to break down the technology any further, because it's complicated enough to make HCCI look like the Flintstone car. The upshot: the MUSIC engine delivered 20 percent better efficiency than a standard Duratec in the urban cycle, with an even better 42.5 percent improvement at near idle speeds. The downside? Power is cut nearly in half, delivering only 50 hp (from a two liter engine) at 4k rpm. Developers claim their results could improve with better injection equipment, but add the cost and reliability issues and you have a yourself a hefty engineering to-do list before this technology hits the streets.
8 Comments on “Merritt Unthrottled Spark Ignition Combustion Explained. Or Not....”
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20% better fuel economy in 2.0 engine that only delivers 50hp when under operation (not at idle speeds)???
Hmm – get a Hybrid – 20% better fuel economy when running – > 100hp plus torque from electric engine the engine shuts of instead of idling which uses no fuel.
Any world on the NOx pollution of running lean?
Wouldn’t this be better for generators than cars?
You know, I always liked the joke about the Segway that all you need is a 3rd wheel and you can eliminate most of the cost in producing the thing. America will destroy itself trying to maintain the status quo of cars and oil for everyone. Move more freight by rail, that will reduce demand for diesel and roads will last longer. Build high-speed rail which will reduce our aviation woes. Expand mass transit. These are low-tech, obvious solutions.
Now wait a minute, the baseline 2.0 Duratec doesn’t have direct injection, which technology is but a subset of the MUSIC design. If MUSIC technology gives a 50% reduction in power output then the whole exercise is pointless. A smaller 1.2 liter engine with direct injection would probably hit the same or better fuel economy as the MUSIC did whilst being much simpler and lighter.
This sounds like another going nowhere science project. The world has seen countless such things over the years.
How does this more [thermally] efficient engine integrate with existing catalytic converter technology. Also, I’m not sure I’d put out a press release saying ‘50% less power using 20% less fuel.’ That makes the engine 30% less efficient in converting dead dinos to heat, no?
The key application to this technology would be to have the engine opperate like a MUSIC engine at idle/cruise and a regular IC engine on power (can’t say ‘at full throttle’). Don’t know if that’s possible without more complicated mechanicals.
and +1 for jthorner
If this is direct injection, then it would be easy to convert it to a 2 cycle with no pollution issues and you get your 50% power loss back with a power stroke every 360 degrees.
Jon Paul: You know, I always liked the joke about the Segway that all you need is a 3rd wheel and you can eliminate most of the cost in producing the thing.
They make those too – saw one on a kid’s show last week. Along with the cost reduction there was a SERIOUS coolness reduction too. VBG!
I used to like Segways until a friend was riding one and one wheel lost traction on a slick floor. Not the Segways’s fault but it dumped her hard and she badly hurt her wrist. Got several opportunities to ride that Segway. Neat machine. I just don’t have anywhere I need to ride something like that and can’t reconcile the cost which is more than what I paid for several of my cars of the years.