Petrol and diesel engines are as different as night and day.
Generally speaking, the former offers more performance and refinement, while the latter has greater low-end torque and efficiency.
But what if there was an engine that offered the best of both worlds?
It would be an evolution in internal combustion engines.
Mazda claims to be the first carmaker ever to achieve this with Skyactiv-X, a petrol engine that also performs compression ignition like a diesel engine.
Mazda calls this process Spark-Controlled Compression Ignition (SPCCI).
SPCCI ALLOWS LEAN-BURN COMBUSTION
Skyactiv-X needs SPCCI so it can use very high air to fuel ratios (AFR), which improves fuel economy.
The ideal (stoichiometric) AFR is 14.7:1, but in Skyactiv-X, this can be up to 36.8:1.
In regular engines, an AFR of over 14.7:1 means you are running very lean, and there is chance that the fuel will not ignite.
SPCCI solves this issue. It compresses the air-fuel mixture to near-ignition, then triggers combustion with a spark.
Skyactiv-X also has a compression ratio of 16.3:1, which is similar to diesels. I know of no other production petrol engine with such a figure.
WHAT’S THE ADVANTAGE OF SKYACTIV-X AND LEAN-BURN?
Skyactiv-X lets you produce even more power without using too much more fuel.
For instance, the 2-litre Skyactiv-X engine in the Mazda 3 produces 178hp and 224Nm. It’s combined fuel consumption is 15.9km/L
The 2-litre Skyactiv-G motor, on the other hand, has 162hp, 210Nm and a fuel economy of 16.9km/L.
HOW DOES SKYACTIV-X PERFORM?
I took a short drive in a Mazda 3 with Skyactiv-X. The motor was responsive and the delivery, smooth.
The changeover between normal combustion and SPCCI was seamless. Unless you see the SPCCI indicator, you cannot tell when the engine switches over.
And like other Mazda motors, this one was also rev-happy.
Mazda remains mum about when other models will get Skyactiv-X.
However, I expect the Mazda 3 Skyactiv-X to reach Singapore in the first half of 2020.
Mazda 3 Hatchback Skyactiv-X 2.0 (A)
ENGINE 1998cc, 16-valves, inline-4
MAX POWER 178hp at 6000rpm
MAX TORQUE 224Nm at 3000rpm
GEARBOX 6-speed automatic with manual select
0-100KM/H 8.6 seconds
TOP SPEED 216km/h
CO2 EMISSION 142g/km
FUEL CONSUMPTION 15.9km/L
PRICE INCL. COE To be announced (car expected to arrive in H1 2020)
AGENT Eurokars Group