http://www.dailytech.com/Mazda+Expe...Skyactiv+2+Engines+Come+2020/article34052.htm
Interesting tidbit.
Mazda is already discussing Skyactiv 3 as well
Mazda only recently started introducing its Skyactiv engines to its different vehicle models, but the automaker is already talking about the upcoming Skyactiv 2 -- and even Skyactiv 3 -- engines for the next decade and beyond.
According to a new report from Automotive News, Mazda plans to gain 30 percent better fuel economy with its Skyactiv 2 engines, which are expected to have a 2020 release date. A 30 percent improvement in fuel economy would make the already impressive Mazda3 rise from 29/41 mpg (city/highway) in its more efficient trim to 38/53 on regular unleased gasoline.
Mazda plans to achieve this 30 percent increase in fuel economy by improving the internal combustion of the Skyactiv 2 engines. More specifically, the Skyactiv 2 engine's compression ratio would be bumped up to 18:1 from a current level of 14:1.
This higher compression is able to reach the same combustion temperature as the current engines, but with a leaner mix of fuel -- meaning improved fuel economy.
The Skyactiv 2 engines will utilize homogeneous charge compression ignition (HCCI), which compresses the fuel-air mixture to a high enough pressure and temperature that it ignites by itself without needing a spark. This allows for more complete fuel combustion and lower nitrogen oxide emissions.
However, the Automotive News report indicates that HCCI won't come easy. Engineers must first expand the range of engine speeds for HCCI specifically, because the engine revving too quickly can result in a misfire due to the high number of revolutions, and if revved too slowly, it can misfire due to low temperatures.
Aside from that, engine cooling and the engine's tendency to behave differently based on the use of different fuels need to be figured out.
The main goal with Skyactiv 2 is to meet European carbon dioxide emissions standards of 95 grams per kilometer in 2020, but Mazda is looking even further ahead at meeting Europe's standards of 65 grams per kilometer in 2025 with Skyactiv 3.
Mazda didn't go into great detail about Skyactiv 3, but the automaker plans to make more energy available for powering the wheels by limiting the fluctuation of heat in the combustion chamber and reduce losses from exhaust and cooling. Mazda hopes to reach well-to-wheel carbon dioxide emissions with Skyactiv 3 that rival electric vehicles.
Mazda first introduced Skyactiv engines to the U.S. market in 2011, starting with the Mazda3 sedan. Since then, they've been added to the Mazda6 sedan and CX-5 crossover.
Mazda has been trying to bring the Skyactiv-D diesel engine to the U.S. via the Mazda6, and was supposed to have achieved this by the second half of 2013. However, in September of last year, it was announced that delays in emissions testing has pushed that timetable to late spring of 2014.
Interesting tidbit.