* Says it is first to commercialise compression ignition tech
* Automakers have been working on compression ignition for decades
* New engine 20-30 pct more efficient than current engine
* No plan to supply engine to other automakers - exec (Adds executive comments, further plans, context)
TOKYO, Aug 8 (Reuters) - Mazda Motor Corp unveiled plans for the world's first commercial gasoline engine using compression ignition, placing traditional engines at the centre of its strategy days after saying it would develop electric cars with Toyota Motor Corp.
Mazda, whose research and development (R&D) budget is a fraction that of Toyota, could be the first automaker to commercialise a technology that many peers including General Motors Co and Daimler AG have been working on for decades.
Mazda on Tuesday said it would start selling cars equipped with the new engine from 2019, even as other automakers increasingly turn to on electric vehicles against a landscape of tightening environmental regulation.
"We think it is an imperative and fundamental job for us to pursue the ideal internal combustion engine," said Mazda's head of R&D Kiyoshi Fujiwara.
While "electrification is necessary ... the internal combustion engine should come first," he told reporters.
The news follows Mazda's Friday announcement of a capital tie-up with Toyota, an alliance that will see the pair build a $1.6 billion U.S. assembly plant and work together on electric vehicles.
Mazda's engine technology is the automaker's "heart", said Executive Vice President Akira Muramoto. He said Mazda did not plan to supply the new engine to other automakers.
Mazda said the new engine, to be called SKYACTIV-X, would be 20 to 30 percent more efficient than its current SKYACTIV-G engine.
It also said it would begin introducing electric vehicles and electric technology from 2019, focused on markets that restrict the sale of other cars or provide a clean source of electric power.
The automaker also said it aimed to make autonomous-driving technology standard in all of its models by 2025. (Reporting by Sam Nussey and Maki Shiraki; Additional reporting by Norihiko Shirouzu; Editing by Chang-Ran Kim and Christopher Cushing)