MAZDA IS WORKING on a range of improvements for its petrol and diesel engine line-up in a bid to improve fuel efficiency. The first engine in the improved range due to launch sometime in 2011.

Mazda is targeting a 30 percent improvement in efficiency across its entire model range by 2015 - a figure that does not include gains from start stop systems, regenerative braking or hybrid powertrains, although Mazda will continue to develop those technologies.

Greater use of direct injection and variable valve timing will be responsible for much of the fuel economy gains,  and the development of a new range of automatic transmissions will also help lower fuel consumption.

Mazda will be concentrating its efforts on the company’s volume-selling four-cylinder petrol engines, opting not to fiddle with the Ford-sourced V6 motors used in some of its vehicles. Diesel models will also get some attention in the form of new automatic transmissions specifically designed for use with diesel-powered engines.

A new direct-injected rotary engine is also rumoured to be in the offing, and could be fitted to the RX-8’s successor. The 16x rotary reportedly boasts a greater than 30 percent improvement in fuel economy over the current 13B-MSP used by the RX-8, and also weighs less.

The new engines will be gradually introduced across Mazda’s line-up, and the Japanese automaker has no intention of marketing them specifically towards eco-conscious buyers.

“We want to provide this technology to all owners, not just through a few eco-friendly vehicles,” said Seita Kanai, head of research and development at Mazda.

The first models to receive the new efficiency-optimised petrol engines will likely be the next-generation MX-5 and Mazda5 people mover. According to Mr Kanai, the entire Mazda range will feature the new engines by 2015.

Mazda currently only offers two direct-injected petrol engines: the naturally-aspirated MZR 2.0 DISI used by the Japanese-market Mazda5, and the turbocharged MZR 2.3 DISI used by the latest Mazda3 MPS.