Mazda will debut its new Skyactiv-X engine technology in a few weeks, but it's already testing the compression-ignition drivetrain on the road—and it wants you to know about it. Spy photographers have ...

Homogeneous charge compression ignition (HCCI) engines combine a diesel's torque and fuel efficiency with a gas engine's cleaner emissions. The HCCI technique has been a goal of automakers since the ...

Any diesel-engine manufacturer that confidently claims it produces an oil-burner with the “world’s lowest compression ratio,” will no doubt draw the immediate attention of inquisitive enthusiasts, ...