Mazda's powertrain R&D department has always been a bit...odd. Sequentially turbocharged rotary engines, supercharged 5-stroke V6s, compression ignition gasoline engines, they've cooked up some unusual creations. Now, they've apparently filed some patents for a new supercharged 2-stroke compression ignition gasoline of unknown cylinder count and purpose.
United States Patent Application: 0220034265 (uspto.gov)
Supercharged 2-stroke isn't that uncommon, Detroit Diesel has been making them for decades. Gas engine is a little unique, but still not much. If I read the patent application correctly it goes from compression ignition to spark ignition depending on load?
Wonder what the use case will be.
In reply to Mr_Asa :
It's the Skyactiv-X system applied to a supercharged 2-stroke. Not implying supercharged 2-strokes are new, but they are certainly an odd choice and due to emissions have been considered a bit of a dead end. Ford was working with Achates Power and Fairbanks-Morse on that opposed-piston, supercharged 2-stroke, 6-piston, 3-cylinder engine, but with Ford's recent commitment to EV, I feel like that has fallen by the wayside.
Mazda has been weird for a loooong time. If anyone would file a patent for this, it's Mazda.
I doubt we see it in anything production. They didn't even bring the Skyactiv-x here for some reason.
2-stroke engines like this and the Detroits don't have the emissions problems of the 2-strokes that mixed gas and oil. That was the biggest part that hurt the 2-stroke in the emissions area. It is interesting to see a sort of resurgence of the 2-stroke engine in the tight emissions era.
81cpcamaro said:2-stroke engines like this and the Detroits don't have the emissions problems of the 2-strokes that mixed gas and oil. That was the biggest part that hurt the 2-stroke in the emissions area. It is interesting to see a sort of resurgence of the 2-stroke engine in the tight emissions era.
With a gas engine, direct injection is the key to low emissions. Without it, you still have the problem of blowing some of the fuel/air charge out the exhaust on every cycle even if you're not using the crankcase for scavenging and burning a fuel/oil mix.
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