Mazda has added a fifth engine to its Skyactiv range with the arrival of a 1.5-litre petrol unit, the smallest in the series so far.
It makes its debut in the latest Mazda3 five-door hatch and four-door Fastback, both of which are about to go on sale in the UK.
The 1.5 is expected to be the choice of only 5% of Mazda3 buyers, but its real significance will be seen when the next Mazda2 comes along. Then it will be the mainstay of Mazda's B-segment sales.
Mazda is also believed to be developing a B-segment SUV based on the next Mazda2 as part of its plans to introduce five new models between now and 2016.
The Skyactiv 1.5 develops 99bhp and 150Nm of torque and has official combined fuel consumption of 55.4mpg with CO2 emissions of 119g/km in the Mazda3.
These figures are exactly the same as those for the 118bhp 2.0-litre SKYACTIV unit, but buyers will still save with the smaller engine because it costs £300 less and keeps insurance four groups lower.
The new engine is available only in SE and SE Nav versions of the Mazda3, with prices starting at £16,995.
By 2015 Mazda will have nine out of 10 cars in its range powered by SKYACTIV engines, compared with only 8% last year.
The technology is the first step in a chain aimed at bringing down the overall CO2 of combustion engines to the same level as those of electric cars powered by electricity created from coal.
At the Tokyo Show a couple of weeks ago Mazda announced it is working on two new combustion technologies which will reduce the fuel consumption of an average car by around 30% and make petrol engines as economical as diesels.
Mazda claims its Skyactiv engines are already delivering better real-world economy than the smaller turbocharged units from rivals which, on paper, are more frugal.
The Skyactiv range is made up of the new 1.5, 118bhp and 163bhp 2.0-litre petrol units and 148bhp and 172bhp 2.2-litre diesels. Some of the engines are already installed in the Mazda 6 and the CX-5.