Mazda 2 SkyActiv-D Clean Diesel Challenge 41

The Japanese transport ministry has called for the implementation of real-world diesel emissions tests following findings that real-world data for several models from key manufacturers failed to comply with the nation’s vehicle emissions regulations.

According to The Japan Times, diesel variants of the Nissan X-Trail, Land Cruiser Prado and Toyota Hiace commercial van emitted up to 10 times more nitrogen oxide (NOx) than permitted. It was also noted that unlike the Volkswagen diesel scandal, no “defeat devices” were found in any of the tested vehicles.

The Mazda models that were tested, the CX-5 2.2 diesel SUV and the B-segment Demio (Mazda 2) 1.5 diesel fared well in the tests, showing real-world emissions that closely matched its lab results. The Japanese publication also claims that none of the manufacturers have much to worry about in terms of penalties because current legislation only requires vehicles to pass tests in a lab setting and not in the real world.

The Japanese government’s sentiment echoes that of Matthias Mueller, the new Volkswagen Group CEO, who also called for European authorities to adopt real-world emissions and consumption tests.

“The industry-wide discrepancies between official test results and actual usage is no longer tolerable. We, the industry, need to take a new path,” said Mueller. French car maker, PSA Peugeot Citroen, also announced last October (2015) that it will be publishing fuel economy figures for its “main vehicles” based on actual real-world testing conditions.

One such resolve for the matter has been identified as Emissions Analytics’ on-the-road testing programme, which is said to closely match real-world tests. The planned World Light Test Procedure (WLTP), developed under the workings of the UNECE WP29 forum, targets a more realistic representation of fuel economy and pollutant/CO2 emissions.