Mazda reveals 1.5L ‘clean’ diesel

MAZDA has unveiled its smallest passenger-car diesel engine yet in the guise of a 1.5-litre SkyActiv D, but it may not see the light of day in Australia.

Embodying a lower-than-usual compression ratio of 14.8:1 for optimised efficiency, the four-cylinder direct-injection unit with a variable turbine geometry turbocharger is slated for the all-new Mazda2 light car to be unveiled globally next month.

However, it is unlikely to surface in Australian-spec versions of the popular five-door hatchback when sales commence in October, as the added expense of the technology, combined with comparatively low fuel prices and more economical petrol engines have rendered the non-premium end of the light-car diesel market dormant.

Instead the 1.5 SkyActiv D may surface in the top-secret CX-3 compact SUV that is likely to debut either next year or sometime in 2016.

It could also end up in lower-spec versions of the current-gen Mazda3, sitting under the upcoming 2.2-litre Astina XD that arrives in August and will serve as a performance flagship starting from about $40,000.

Delivering 77kW of power at 4000rpm and 250Nm of torque between 1500rpm and 2500rpm, the new turbo-diesel offers torque outputs similar to that of a 2.5-litre petrol engine.

To help it meet Japan's Post New Long-term Emissions Regulations, the 1497cc unit employs an expanded homogeneous lean burn range, a cut in mechanical resistance and special insulation technology designed to mitigate cooling loss issues.

It was also feature Mazda's i-Stop idle stop device, ELOOP brake energy regeneration and six-speed transmissions in either automatic or manual guise.

Meeting Euro6 emissions targets, Mazda says the 1.5 SkyActiv D is clean enough not to need a costly NOx after-treatment regime.

Fuel consumption and carbon dioxide emissions data is yet to be released, but expect Mazda to issue further information closer to the Mazda2's unveiling.

The diesel’s Australian no-show is not surprising, given that Ford dropped the oil-burning Fiesta TDCi – featuring the same engine that Euro versions of the existing Mazda2 have utilised for some time – when the WZ facelift arrived almost a year ago.

Volkswagen will also discontinue the Polo TDI turbo-diesel in Australia when the facelifted version hits showrooms in September.

In both cases, each car-maker said the latest-generation smaller-displacement turbo-petrol engines (1.0-litre EcoBoost in the Fiesta Sport and 1.2-litre TSI in the Polo) offer nearly as much efficiency and economy.

The only models in the light-car segment to offer diesel power are all premium-priced offerings – the Fiat Panda Trekking ($24,000), Audi A3 1.6 TDI ($29,900) and Mini Cooper D ($31,800).

Only Renault has refused to rule one out, with the Clio dCi still slated for an on-sale date in Australia later in the year or early in 2015.