Mazda will launch new petrol and diesel engines and an automatic transmission at the Tokyo motor show next month.

The new engines are the Sky-G petrol and Sky-D clean diesel units with lower CO2 emissions, reduced fuel consumption and increased torque due to optimised combustion efficiency.

The direct-injection petrol engine delivers "significantly improved fuel economy and output performance due to enhanced thermal efficiency", Mazda said. The block is newly designed to reduce mechanical friction and achieve an optimal air-fuel mix, and a direct fuel-injection system is employed for the wide variety of spray profiles that are possible, enabling the maximum expansion ratio to be achieved.

Fuel economy and torque are improved by about 15% compared with the current two-litre engine due to next-generation fuel injectors and a variable-valve timing mechanism. The engine enables fuel economy equivalent to the current 2 (Demio in Japan) to be achieved in a larger vehicle the size of a 3 (Axela in Japan).

The diesel's new block reduces mechanical friction to the level of a petrol engine. By optimising the pressure and temperature in the cylinders, the shape of combustion chambers, and the fuel injection rate, combustion begins at the best timing in terms of thermal efficiency. Piezo injectors, a two-stage turbocharger and other technologies improve fuel economy by about 20% over the current 2.2-litre unit.

This engine gives fuel economy equivalent to the 2 in a larger vehicle the size of a 6 (Atenza in Japan), the automaker claimed.

The so-called Sky-Drive automatic transmission is highly efficient so contributes to substantially improved fuel economy and delivers a more direct feel compared with the current unit, Mazda said. It improves fuel economy by about 5% due to a complete redesign that significantly reduces mechanical friction, a revised torque converter and clutch with minimised slip and an optimised lock-up mechanism. A rapid clutch action was achieved by identifying the minimum amount of fluid necessary. This also helped to realize a direct feel similar to a dual clutch transmission.