Mazda patents wacky supercharged two-stroke engine

Mazda has submitted a patent application for a two-stroke supercharged engine in the US that could act as a simple, low-cost range-extender for its future EVs.

While other car-makers abandoned two-stroke engines decades ago over noise, refinement and emissions-related issues, Mazda has revived it for its latest powertrain concept.

Of course, the new blueprints are far more advanced than an engine you'd normally use to mow your lawn.

At low loads, for example, the patent suggests the two-stroke coverts to a compression-ignition diesel-style engine for maximum efficiency.

At high speed, meanwhile, it can then switch to spark ignition for maximum power.

As part of its design, the new engine also uses variable valve timing that is necessary to maintain a high compression for the diesel cycle.

The tech mirrors Mazda's advanced SKYACTIV-X engine that can also swap from compression-ignition to spark-ignition.

According to Mazda, the supercharged two-stroke offers improved fuel economy over regular four-stroke engines.

There's no word on how the car-maker has overcome the long list of disadvantages involved with two-stroke combustion, not least the problem over their emissions.