The diesel engine has been embroiled in a lot of controversy lately. With several carmakers caught cheating on emissions, could the love affair with this frugal oil burner be over? Is the future finally all about fancy gasoline hybrids or complicated electric vehicles? Though stringent emissions have yet to be implemented in the Philippines (the country is still at Euro 4 while others are moving towards Euro 6), one carmaker has spearheaded the move for a truly clean diesel; one that doesn’t require a cheat device to meet the most demanding emissions standard in the world: Mazda.

The story of the Mazda CX-5 is a well told one (read our reviews: 2012 M/T and AT, 2013 AWD Sport, 2014 2.0 Pro, 2015-2016 AWD Sport). First introduced in 2012, it’s the first “fourth-generation Mazda”; the one that combined the head-turning looks of KODO with the holistic suite of vehicle tech called Skyactiv. It’s been praised endlessly by the public and pundits alike, calling out the stellar driving dynamics and knock-out styling as just two of its endless positive characteristics. But in as much as it’s a great drive, people wanted more. They wanted more power and efficiency crammed into that shapely body. The result is a fitting swansong to the current CX-5: the AWD Skyactiv-D.



That single letter, the “D” appended to the Skyactiv badge, uncovers an entirely new story for Mazda. Although Mazda is the least one you’d expect selling diesels, it’s been a huge success for a company that has built a reputation for defying convention. Before Skyactiv-D, only 1 percent of cars sold in Japan were diesels. Turned off by their poor refinement and emissions, Japanese consumers opted for hybrids. Five years later and thanks in huge part to Mazda’s efforts, that share has grown to about 8 percent. Half of that number is Mazdas, accounting for 36 percent of their total sales volume in Japan (103,771 units).

Mazda attributes the success of its diesel engines thanks to three key Skyactiv-D traits: first is that it offers 20 percent better fuel economy compared to diesels with the same displacement and power. Second, it has a smooth and linear response with a relatively high 5,200 rev limit. Third, it complies with global emissions regulations (up to Euro 6) without expensive exhaust treatment or cheating.



Skyactiv-D has achieved all these because Mazda took a conventional diesel and turned it over its head. For starters, it has a 15 percent lower combustion ratio (a gasoline-like 14.0:1). By lowering the compression ratio, Mazda has effectively lowered the temperature and pressure at the piston’s top center. This results in a longer ignition alleviating the formation of unwanted exhaust gases and soot. At the same time, the lower compression ratio reduces the stresses put on the engine and allows engineers to use an aluminum cylinder block. Not only is this 25 percent lighter, but it also offers reduced friction without any sacrifice to engine service life.

Of course, going low compression has its problems: poor cold-start emissions and misfiring during warm-up. Mazda solved this by adopting multi-hole injectors that offer different injection patterns based on driving conditions (up to 9 injections per combustion) as well as Variable Valve Lift (VVL) on the exhaust valves. This combination offers more precise fuel injection control along with the quick stabilization of compression temperatures eliminates poor cold-start emissions and engine misfiring.



The final piece of the Skyactiv-D puzzle is the use of a clever twin turbocharger system that uses one small one and one large one that operate selectively based on driving conditions. Not only does this give high torque at low speeds and high power at high speeds, but it works synergistically with the low compression ratio to reduce emissions and fuel consumption even further.

All this tech talk translates beautifully on the road as the Skyactiv-D powered CX-5 presents itself as the ultimate version of Mazda’s compact crossover. With 173 horsepower and 420 Nm of torque, it has enough grunt to make any self-professed petrol head renounce his hate for diesel. Whether it’s for that quick overtaking maneuver on C5 or effortless cruising on the expressway, this engine can do it all. And unlike its gasoline counterpart which needs to be wringed, there’s always a surge of power on tap. In fact, 50-60 percent throttle application is all that’s needed to scare your passengers. Plus, it’s quieter and more refined than other diesels out there, the Europeans included. The diesel clatter intrudes more in this particular application than in the Mazda6, but that’s down to the latter’s more extensive sound insulation.



Like its diesel-powered executive sedan counterpart, the CX-5 Skyactiv-D comes with a 6-speed automatic. Unlike the Mazda6 though, the CX-5 doesn’t come with paddle shifters. Though the gearbox works well enough, commanding an up- or downshift quickly, there’s some noticeable shift shock whenever first gear is engaged.

In addition, the CX-5 doesn’t have i-ELOOP installed. It does, however, have the i-stop idle start/stop system. Though normally not talked about, Mazda’s i-stop system itself is unique in that it requires just a single cycle to restart the engine (typical diesel start/stop systems require two). It does this by carefully positioning the pistons as the engine stops. As a result, the engine restarts in just 0.4 seconds, achieving the world’s fastest diesel engine restart time. This along with Skyactiv-D enables the CX-5 to squeeze out 10.42 km/L at an average speed of 15 km/h.



Four years on and the CX-5 is still the sportiest compact crossover out there. It’s far nimbler than any other offering in the segment, achieving an intricate balance of linearity in its steering and responsiveness in its chassis. The ride is most definitely firm, but road imperfections are soaked well enough as not to cause any passenger complaints. However, because of the heavier diesel hardware, this version of the CX-5 does tend to understeer and lean more when cornered hard. It doesn’t distract from the overall fun-to-drive experience though.

The CX-5 managed to introduce many firsts for Mazda and as a result, has become a shining example that a vehicle engineered by a company that defies convention can still achieve mainstream success. The pinnacle of the CX-5’s achievement though is perhaps the introduction of Skyactiv-D. More than just breathing new life to a well-told story, by defying what a diesel engine is and what it can do, Mazda is proving that oil burners can be both sporty and clean. As the first-generation begins to bid adieu, it has done so with a balanced driving performance combined with clean emissions and a clear conscience. If this is what the first-generation CX-5 is, imagine what the all-new model can deliver.