Under the ClearTec label, Mitsubishi this week started in the UK with its new-generation Colt.
Within three years, all Mitsubishi models except Triton and Pajero will have the option of low-emission, high-efficiency features.
Mitsubishi says that diesel was no longer cost effective for motorists who cover low annual distances.
In Australia, Mitsubishi will soon unveil low-emission systems for its range. Spokesperson Lenore Fletcher says ClearTec was not on Australia's near-term radar.
The UK-spec Colt ClearTec 1.3-litre petrol reduces CO2 emissions by 24g/km (17 per cent) to 119g/km compared with the standard Colt 1.3.
It costs about 5.4 per cent more than a standard version in the UK.
That means Australian buyers would pay $16,590 (plus on-road costs) for a ClearTec Colt compared with the base Colt price of $15,740 (plus costs).
Mitsubishi claims the 1.3-litre (the Australian 1.5-litre is not available in the UK) ClearTec will get up to 4.3 litres/100km — with an overall average of 5 l/100km — and argues it is a less expensive car to buy and run than small-capacity diesel cars.
The key to ClearTec is a list of low-emission features, primarily auto stop-and-go that in traffic or when stopped, switches off the engine.
It restarts primarily when the clutch is engaged, though there are six other sensors that can restart the engine. For safety reasons, the engine will stop only if it doesn't detrimentally affect other functions such as the windscreen demister or airconditioner.
It is only offered on models with manual transmissions.
Mitsubishi says the stop-and-go system will reduce emissions and fuel consumption by 25-30 per cent over the standard car.
ClearTec also adds low rolling resistance tyres (with an 18-33 per cent reduction); higher final drive ratio (16-26%); high-efficiency alternator (11-15%); low viscocity oil (2-3%); and low resistant engine fittings (10-13%).
It results, at best, in a car that has a CO2 reduction of 24g/km.