New tech to boost petrol efficiency

The next generation of petrol engines will offer the same fuel economy as hybrids without the extra weight and cost. So say engineers at US technology company Delphi, who’ve worked out how to incorporate the direct-injection method of ignition used in diesels into petrol engines. And the potential benefit is staggering.

Harry Husted, Delphi’s chief engineer for advanced powertrain development, told Auto Express: “The results of initial simulation work show this technology could improve engine efficiency by up to 50 per cent.”

In conventional petrol engines, a spark ignites the mixture of fuel and air. But in diesel engines, it’s the heat of compression that ignites the fuel and air mixture without the need for a spark. This allows the fuel to burn faster and more efficiently.

Until now, though, engineers have been unable to use the direct-injection method with petrol, because it’s too volatile to effectively control.

Delphi’s gasoline direct-injection compression ignition system overcomes this problem by using sophisticated valve timing, intake and exhaust tech to inject petrol in precisely controlled bursts. The company has successfully developed and tested a single-cylinder engine prototype and is already working on a more advanced system.

Husted added: “A multi-cylinder engine is being developed and will be ready to test later this year. It’s going to be a very torquey engine, with a similar feel to a diesel.”

And the new engine will have an immediate advantage over a diesel – and extra appeal to manufacturers: as unleaded fuel burns more cleanly than diesel, petrol engines don’t need an expensive and highly complex particulate filter. The new engine could be on sale by 2020.