HIROSHIMA, Japan - Mazda Motor announced Monday that it will roll out a new clean diesel engine to world markets in 2009. Also in 2009, the automaker will introduce its newly developed Smart Idle Stop System (SISS) that is claimed to improve gasoline-engined vehicles' fuel economy by 10 percent.

The Mazda MZR-CD 2.2-liter clean diesel engine is notable for a diesel particulate filter, or DPF, that has an improved way of removing soot from exhaust gases. Mazda claims its catalyst activation mechanism is a world first and lets the engine burn off particulates about 60 percent faster. It also has improved fuel injectors and a lower compression ratio than the current Mazda 2.0-liter diesel, which Mazda says also improves fuel efficiency. The new engine makes a maximum 182 horsepower and 295 pound-feet of torque. Its fuel economy is claimed to be 42 miles per gallon.

The clean diesel will be introduced in Europe next year before a gradual rollout to markets worldwide, Mazda says.

The new Mazda Smart Idle Stop System (SISS) is another gambit to improve fuel economy. Mazda says the system improves fuel economy by 'around ten percent' in urban areas, based on results in Japan's 10-15 mode tests.

SISS shuts down the vehicle's engine automatically when the car is stationary. Instead of restarting the engine normally, the SISS system's innovation is that it uses direct-injection technology — injecting fuel directly into the cylinder while the engine is stopped and then igniting it to generate downward piston force — to restart after a shutdown. This, Mazda says, ensures a smooth experience for the occupants of the vehicle when driving resumes. Engine restarts happen in 0.35 second, Mazda says, thanks to the precise control the SISS system provides.

Mazda will bring out SISS on production vehicles in 2009.