Currently, the SkyActiv-G engines run on a compression ratio of about 14.0:1 but Mazda is looking to develop its homogeneous charge compression ignition technology (HCCI), where the fuel-air mixture is ignited by compression rather than a spark, like in a diesel engine.
This means bumping the compression ratio even higher to 18.0:1 and ensuring the combustion process is precise so as to prevent engine knocking. As of now, the efficiency of levels of Mazda’s petrol engines stand at 40% but in the next five years, it hopes to achieve 60% with cleaner emissions and near diesel-like levels of efficiency.
Closer to home, Bermaz Motors organised the SkyActiv Challenge that employed the Mazda 2, Mazda 3, and Mazda CX-5 which attempted to illustrate the SkyActiv engines’ efficiency with impressive results.
Speaking to Autocar, Saruwatari mentions that 30% of the fuel’s energy is lost through the exhaust system and this is something Mazda is investigating as part of its SkyActiv efficiency program.
Mazda are also in a partnership with Toyota which may see a plug-in hybrid model being produced, further adding to the efficiency capabilities of the future generation 2 SkyActiv engines.