While conventional petrol engines are constantly being overlooked in favour of full electric motors, hybrids and diesels in the race to make the motoring world much greener, Nissan has created a high-tech 1.2-litre supercharged petrol motor that emits just 15g/km of CO2 when fitted to the new Nissan Micra.
This supercharged Micra is about to make its European debut at the Geneva Motor Show and while the new Micra is due in South Africa in three months from now, this version will not be sold here.
Known as the DIG-S, the engine is a direct injection unit with a supercharger ? hence the car's name: Direct Injection Gasoline-Supercharger.
The highly advanced new engine uses the Miller cycle and direct petrol injection to raise the compression ratio to 13:1 for greater combustion efficiency and a supercharger for instant throttle response and added power.
As well as delivering ultra low CO2 emissions, the lightweight, low-friction 1198cc three-cylinder unit produces the power expected from a conventional 1.5-litre four-cylinder engine.
To that end, it produces 72kW and 142Nm, while the manual version sips just 4.0 litres per 100km on the combined cycle, equating to CO2 emissions of 95g/km. It's also available with a CVT gearbox, in which case it emits 115g/km.
In creating this engine, engineers minimised heat, friction and pumping losses as much as possible. What's more, its three-cylinder configuration gives many benefits including less weight and further reductions in friction loss, thanks to having fewer moving parts. Further gains are made thanks to the adoption of advanced engine management systems with Start/Stop and energy regeneration.
Nissan's Pierre Loing said: “No other petrol-powered compact hatchback can beat its overall efficiency... and it is more than a match for an equivalent diesel.”
“We have been able to achieve this ultra low CO2 figure in a cost effective package and without the complication of particulate filters needed to clean up diesel engine emissions and which are not entirely compatible with a car that spends much of its life in the city.”