Mazda rewrites the petrol engine rule book with Skyactiv-X tech
“The Skyactiv-X petrol engine uses what Mazda calls ‘Spark Controlled Compression Ignition' technology. Making this work has been something of an engineering holy grail for car-makers, and while others have tried, Mazda is the first to put it into production
WE have already praised the beauty of the new Mazda 3 on these pages, but beneath its curvy exterior the family car also stands out for its genuinely innovative Skyactiv-X engine, writes William Scholes.
The car was launched with diesel and regular petrol engines, and the arrival of Skyactiv-X is hotly-anticipated; that’s getting ever-closer, with Mazda now announcing prices for cars using the high-tech unit.
Skyactiv-X is a type of petrol engine that uses what Mazda calls ‘Spark Controlled Compression Ignition’ technology.
Making this work has been something of an engineering holy grail for car-makers, and while others have tried, Mazda is the first to put it into production.
Put most simply, it means the engine offers the free-revving characteristics of a petrol engine with the torquey responsiveness of a diesel, as well as running very ‘lean’ which results in low emissions and strong fuel economy.
Indeed, it runs so lean that the fuel-air mixture injected into the engine’s cylinders has so little fuel that a normal petrol engine with spark plugs wouldn’t be able to fire it.
Being able to run a 16.3:1 compression ratio - the highest of any production petrol engine, and higher even than most diesel engines - is key to how the Skyactiv-X engine is able to work.
It can also operate like a more conventional petrol engine by using a spark plug to ignite the fuel-air mixture under certain circumstances.
Being able to switch seamlessly between a diesel-esque and a more typically petrol combustion cycles is what makes this new Mazda engine revolutionary.
As with the conventional petrol engine offered in the Mazda 3, the Skyactiv-X car gets a mild hybrid system to recover kinetic energy.
The debut iteration of Skyactiv-X is a 2.0-litre four-cylinder with 178bhp and 165lb.ft; that torque figure is higher than a comparable Mazda petrol engine, and the peak torque is also produced lower in the rev range.
Fuel consumption on the combined cycle is as good as 52.3mpg using the official WLTP assessment and CO2 emissions are as low as 99g/km.
The Skyactiv-X petrol engine uses what Mazda calls ‘Spark Controlled Compression Ignition’ technology. Making this work has been something of an engineering holy grail for car-makers, and while others have tried, Mazda is the first to put it into production
Mazda 3s with the Skyactiv-X engine can be ordered now, with the first cars expected to reach customers from October.
Prices start from £23,555. The engine can be ordered in Sport, Sport Lux, GT Sport and GT Sport Tech trims, and manual or automatic transmissions.
Also joining the range is at the same time is the saloon body style. It comes with the Skyactiv-X petrol engine and the regular diesel unit. The Skyactiv-X saloon has even lower CO2 emissions, with 96g/km.
And in a further extension of the Mazda 3 range, a four-wheel-drive model is being offered. It comes only as a hatchback in range-topping GT Sport Tech trim with the Skyactiv-X engine, priced at £29,775 with a manual gearbox and £31,295 with the auto.
Skyactiv-X is “another example of Mazda’s convention defying powertrain innovation”, said UK managing director Jeremy Thomson.
“Offering our customers a truly unique blend of fuel economy, low emissions and performance from a petrol engine, Skyactiv-X adds a unique selling point to the Mazda 3, a car that is already winning over our customers with its quality, style and driver appeal,” he said.