Mazda's engine breakthrough: Diesel fuel economy with gas-engine emissions RELIABLE HCCI ENGINES HAVE ELUDED AUTOMAKERS FOR DECADES
August 8, 2017
A homogeneous charge compression ignition (HCCI) gasoline engine has been something of a holy grail for internal combustion engineers for decades, promising the fuel economy of diesel engines but without the soot or nitrogen oxide emissions. This concept essentially achieves internal combustion through compression alone, without the need for sparkplugs, but reliable operation of these engines has eluded automakers. Until now.
Mazda announced this week that it has solved the technical hurdles associated with this technology and that it plans to offer this type of engine, dubbed SKYACTIV-X, in its cars in the near future.
"A proprietary combustion method called Spark Controlled Compression Ignition overcomes two issues that had impeded commercialization of compression ignition gasoline engines: maximizing the zone in which compression ignition is possible and achieving a seamless transition between compression ignition and spark ignition," the automaker said in a statement.
Mazda's design will still use spark plugs to achieve ignition under certain conditions such as low temperatures, but it has indicated that all other issues pertaining to this design have been successfully solved, with the company touting the "super lean burn" characteristics of this new powerplant. The engine is expected to be 20 to 30 percent more efficient than its current SKYACTIV-G family of engines, and an impressive 35 to 45 percent more efficient than the automaker's own 2008 engine with the same displacement. Mazda's compression gasoline engine is promised to deliver 10 to 30 percent greater torque numbers than SKYACTIV-G engines, with Mazda planning to pair the new design with a supercharger. In addition, Mazda says that this new type of of engine will permit much more latitude in selecting gear ratios, which will benefit fuel economy.
How soon will we see this new design in Mazda cars at the dealership? SKYACTIV-X engines are promised to appear in production models in 2019, but the automaker has not indicated in which models we'll see these engines first. The automaker also has not said if its HCCI engines will replace the current crop of SKYACTIV-G engines entirely or if Mazda will opt for a slow rollout of this technology.
Several years ago, electrically-operated valves were touted as the next big thing for internal combustion engines. The benefit was said to be highly variable timing (and mechanical simplicity). Haven't seen anything about them recently though.
Serious about crackers
Posts: 9691 | Location: San Diego | Registered: July 26, 2014
Originally posted by Pipe Smoker: Several years ago, electrically-operated valves were touted as the next big thing for internal combustion engines. The benefit was said to be highly variable timing (and mechanical simplicity). Haven't seen anything about them recently though.
That's the freevalve I mentioned. Google it. Koeniggsegg is working pretty diligently on it.
