Last week’s announcement that Mazda will be putting their potentially game-changing new SkyActiv-X engines into production in the near future was already cause for great excitement. While it does still have spark plugs to ignite the air/fuel mixture, the motor’s dependence on it is circumstantial.
Most of the time, should conditions permit, it will use Homogeneous Charge Compression Ignition (HCCI), squeezing the oxygen and petrol molecules together under high pressure into spontaneously combusting, much in the same way that a diesel motor runs, leading to much improved fuel economy and fewer carbon and pollutant emissions. And to boost power and response, a supercharger could be used, as would some kind of electrification component.
However, as found by Road & Track, Mazda has more intricate plans for forced induction, evidenced by their patent application filed with the US Patent and Trademark Office, detailing an engine that features two turbochargers and an electric compressor in lieu of a traditional parasitic supercharger to boost low-end torque, delivering full boost in milliseconds.
Also worth noting is the longitudinal layout of the in-line four engine instead of being transversely mounted. This indicates a rear-wheel drive layout that currently is only being used in the current MX-5, possibly previewing the powertrain of its successor or even a mostly rear-driven line-up of Mazdas.
Due to the smaller displacement, the dual turbochargers wouldn’t be able to supply enough boost to the new Mazda engines at low end of the rev band, which is where that compressor comes into play. Audi employs a similar solution in their diesel-powered SQ7, endowing it with plenty of boost at any prod of the throttle.
It’s possible that many other Audis will be utilising this electric compressor technology too, particularly with the quick spread of a high capacity 48-volt electrical architecture throughout their line-up. Mazda too will likely rollout 48-volt systems in their cars, evolving its i-Eloop energy recovery system in the process.
With these technologies combined, the Japanese automaker could have the most potent but deceptive fuel efficient engines, and cars, to have ever come into the mass market - a tri-charged clean-burning super-hybrid, which isn’t a bad thing to boast about on the next MX-5.
We’ll just have to wait and see. The first iteration of SkyActiv-X engines are reported to debut in the next generation Mazda3, which should be on the cards for late 2018 or 2019 launch window. From there, it should trickle quickly to all other models.