FUEL saving technology designed to make petrol engines as economical as diesels has been developed by Mazda.
It's part of the Japanese car maker's quest to make combustion engines as efficient as possible and the results will be on the road next year.
The so-called SKYACTIV-X technology encompasses every aspect of vehicle development - and in these days where emissions and electrification have become the buzz words of the auto industry, some of the facts Mazda uses to support its strategy are startling.
We have just sampled the new system in prototype form and the results are impressive, in the region of 50mpg in everyday use if Mazda's projection is accurate.
SKYACTIV-X engines use a blend of spark plug and compression ignition to optimise combustion, producing more power but burning significantly less fuel.
With the help of a mild hybrid powertrain and supercharging the result is a 2.0-litre, four cylinder engine that develops 190 horsepower and 230Nm of torque.
Mazda's current 2.0-litre engine used in the Mazda3 is rated at 120hp with 210Nm of torque.
Not only is the new engine more powerful, it is also said to be between 20 and 30 per cent more economical which pushes fuel return into the mid-to-high 60s and reduces emissions to the mid-90g/km point - cleaner even than Mazda's current 1.5-litre diesel.
On the road, apart from feeling very lively, the SKYACTIV-X engine goes about its job without fluster. Pick-up from low revs is plentiful and so is pull throughout the rev band and it is impossible to detect the difference in combustion mode.
The prototype powertrain was fitted to Mazda3 mules with manual and automatic transmissions and both models had onboard display screens indicating whether the engine was combusting from the spark plugs, compression only or a mixture of the two.
Compression combustion is how a diesel works and the new engine is at its most efficient in that state.
To achieve that, the SKYACTIV-X engine runs with a compression ratio of 16:1 - half as much again of most petrol engines and some 15 per cent more than in Mazda's current SKYACTIV engines introduced in 2012.
Mazda engineers have also eliminated knocking - the spontaneous combustion of fuel at such pressures - and the engine feels and sounds utterly normal whatever the revs.
On our runs in the prototypes the automatic delivered the smoother drive but the manual model found - and held - combustion in the pure compression sweet spot more readily.
Driving a regular 2.0-litre Mazda3 over the same route for comparison, the car averaged 42 to the gallon signalling a fuel return of around 51mpg for the SKYACTIV-X engine.
Other improvements which are part of the SKYACTIV-X programme include a stiffer chassis, more responsive handling and redesigned seats to make driving more comfortable as well as reductions in onboard noise levels.
Mazda's vision is to create a range of cars that are fun to drive while fulfilling society's needs for mobility and don't harm the planet.
Already it has created some of the best looking cars around and its new KAI concept model to be revealed at the Geneva Motor Show in March is a clue to the next generation Mazda3.
While it has a battery powered and plug-in hybrids in the pipeline and has set out its stall to reduce CO2 emissions from its vehicles by 90 per cent come 2050, the car maker believes improved combustion engines are the way ahead.
To back that up it is using a ‘well to wheel' calculation which shows that a mid-sized electric car consumes around 20 kilowatt hours of electricity per 60 mile journey. The emissions produced to generate that electricity equate to 200g/km from a coal fired power station or 100g/km from one running on natural gas.
The average CO2 emissions for EVs are currently 128g/km and with only a 10 per cent improvement in fuel consumption, Mazda's current SKYACTIV-G petrol engine will be on par with electric vehicles.
The SKYACTIV-X system betters that and will be introduced by Mazda in 2019 ahead of its next generation diesel engine which is due for 2020.