Mazda is staking much of its future on the continued existence of the internal-combustion engine, with clever tech like spark-controlled compression ignition set to debut in Mazda's next-generation production-car engine, Skyactiv-X. But the automaker is already thinking even further into the internal-combustion future. that Mazda is working on a new gas engine, Skyactiv-3, which the automaker says will be as clean as an electric vehicle.
Speaking at a tech forum in Tokyo, Mazda powertrain chief Mitsuo Hitomi said that the main goal with Skyactiv-3 is to increase the engine's thermal efficiency to roughly 56 percent. If achieved, that would make the Skyactiv engine the first internal-combustion piston engine to turn the majority of its fuel’s energy into power, rather than waste due to friction or heat loss.
To date, the most thermally efficient automotive internal combustion engine belongs to Mercedes-AMG's Formula 1 team, with an efficiency of 50 percent; AMG hopes the F1-derived engine in the Project One street-legal supercar will achieve 41-percent thermal efficiency, which would make it the most thermally efficient production-car engine in history. Automotive News says Mazda's 56-percent goal would represent a 27-percent improvement over current Mazda engines. Hitomi didn't provide a timeline for when Skyactiv-3 would reach production, nor did he specify how Mazda hopes to achieve such an improvement.
Mazda's claim, that Skyactiv-3 would be cleaner to run than an all-electric vehicle, is a bold one, and requires some unpacking. Mazda bases the assertion on its estimates of "well-to-wheel" emissions, tallying the pollution generated by both fossil fuel production and utility electricity generation to compare Skyactiv-3 and EV emissions. Such analysis reflects the reality that, currently, much electricity is generated through fossil fuels. In regions where electricity comes from wind, solar, or hydroelectric, the EV would clearly win the argument, but that's not the case for many customers today.
If Mazda can make a mass-production internal-combustion engine that achieves more than 50 percent thermal efficiency, it will be an incredible feat—and would likely help guarantee the piston engine's continued survival.