Up until now and despite their popularity in other regions especially in Europe, diesel vehicles have yet to win Japanese consumers. This is mainly due to the costs associated with the NOx emission-reducing technologies that are necessary for diesel engines to meet the country’s stringent exhaust gas regulations.

Mazda says it has overcome this problem with its brand-new SKYACTIV-D 2.2-liter turbo diesel engine that made its debut on the CX-5 crossover.

According to the company, the SKYACTIV-D 2.2 is the world’s first passenger vehicle diesel engine to pass Japan’s Post New Long-Term Emissions Regulations without any need for expensive nitrogen oxide (NOx) after-treatment technology.

Furthermore, Mazda claims that the CX-5 SKYACTIV-D 2.2 will be the first passenger model in the country to combine a clean diesel with an idling stop system, called i-stop, which can restart the engine in 0.4 seconds.

In the CX-5, the 2.2-liter four-cylinder diesel is rated at 175 HP and 420 Nm (309.7 lb-ft) and when linked to an automatic transmission, it delivers an estimated fuel-economy of 18.6km/lt (equal to 43.7mpg US or 5.4lt/100km) on Japan’s JC08 mode test cycle .

The new CX-5 SKYACTIV-D 2.2 will go on sale in Japan in the spring of 2012.