We’ve been waiting with bated breath for finalised
details of Mazda’s novel SkyActiv-X engine, and Hiroshima has finally given us
the lowdown. The Spark Plug Controlled Compression Ignition (SPCCI) mill, which
is now on sale in Europe in the new Mazda 3, promises to deliver the
free-revving performance of a petrol engine and the torque and fuel efficiency
of a diesel, and these figures make for interesting reading.
The 2.0 litre petrol engine delivers 180 PS at 6,000
rpm and 224 rpm of torque at 3,000 rpm, figures that compare favourably to the
155 PS and 199 Nm produced by the regular 2.0 litre SkyActiv-G. Notably, peak
torque arrives 1,000 rpm lower for the SkyActiv-X mill, which should result in
punchier in-gear acceleration.
And while the compression ratio is rated at a heady
16.3:1, the engine can still run on regular RON 95 petrol, not some high-octane
unobtanium fuel. It is paired to a choice of six-speed SkyActiv-MT manual and
SkyActiv-Drive automatic transmissions, with an i-Activ all-wheel drive system
available as an option.
SkyActiv-X models also come as standard with Mazda M
Hybrid, a 24-volt mild hybrid system that recuperates kinetic energy to power
an electric motor that assists during acceleration. Put that all together and
Mazda claims a combined fuel consumption figure of as low as 5.4 litres per 100
km is possible (front-wheel drive manual sedan with the smaller 16-inch wheels)
– and that’s on the more stringent WLTP cycle. With an automatic gearbox and
larger 18-inch wheels that we usually get here, this figure goes up to 6.2
litres per 100 km (6.3 litres per 100 km on the hatchback), which is still an
impressive feat. Carbon dioxide emissions, meanwhile, are as low as 122 grams
per kilometre on the combined cycle.
In case you need a refresher, the SkyActiv-X engine
features compression ignition typically found in diesel engines, enabling the
use of a much leaner air-fuel ratio provided through a supercharger. It still
employs spark plugs to control the ignition timing, allowing for the use of
compression ignition in a much broader range of conditions (up to 90% of the
time, Mazda claims).
The technology is so effective, that the 2.0 litre SkyActiv-X engine’s fuel efficiency equals or even exceeds that
of the 1.5 litre SkyActiv-D diesel engine. The mill is also claimed to offer
improved response and between 10 to 30% more torque compared to the 2.0 litre
SkyActiv-G engine, which Mazda says is equivalent to the larger 2.5 litre
motor.