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Internal combustion 'not going overnight' after Mazda's 'holy grail' breakthrough

Joseph Flaig

The new Mazda CX-8 Crossover SUV (Credit: Mazda)
The new Mazda CX-8 Crossover SUV (Credit: Mazda)

A “holy grail” breakthrough in fuel efficiency means internal combustion engines will not be redundant for several decades, experts have said.

This week, Mazda claimed their new engine is up to 30% more fuel efficient compared to previous models after engineers achieved a long-held goal. The “SKYACTIV-X” uses compression ignition, where fuel and air combust under pressure from a piston rather than sparks from a plug.

It is the first time the technique has successfully been used in a commercial engine. It will work alongside traditional spark ignition using a “lean” mix of petrol and air, reportedly making the engine 20-30% more efficient than Mazda’s previous model and 35-45% over a 2008 equivalent.

Despite rapid advancements in fully-electric vehicles and recently announced bans on petrol and diesel-powered cars, the Japanese company claimed combustion engines “will help power the majority of cars worldwide for many years to come”.

The new technique will “hasten diesel’s demise” amid increased awareness of the fuel source’s negative health impacts but petrol is set to stay for now, said David Bailey from Aston Business School to Professional Engineering.  

“Even though Volvo said every model will have an electric or hybrid model from 2020, they will still be selling cars with internal combustion engines,” said Professor Bailey. “They are not going to disappear overnight, they are still going to be here for decades even while there will be a major shift to electrics.”

If the efficiency gains are as significant as Mazda said, other companies will want to use the engines or copy the technology, he added.

“I think if this really does give a quantifiable improvement in terms of fuel economy then yes, other companies will be very interested in it,” said Jamie Turner from the University of Bath’s Powertrain and Vehicle Research Centre, who called compression ignition a “holy grail”.

“This sort of combustion mode has been out there for a long time in laboratories and research labs at OEMs and nobody has managed to make it work yet. Mazda have – that’s quite a big deal to be honest, so people will be interested to see how they’ve done it.”

Nonetheless, manufacturers and fuel companies believe internal combustion engines will still feature in vehicles even after a 2040 ban on petrol and diesel car sales, Professor Turner added. 


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