Currently reading: Self-supercharging engine in development
An engine with the ability to self-supercharge, rather than using a separate compressor, is in development

A new British-designed and engineered one-cylinder engine has the ability to “self supercharge” without any external forced induction, improving performance and reducing CO2 emissions in the process. 

The 400cc engine is the work of Oaktec’s Paul Andrews, and he believes it has the ability to be produced “in tens of millions” of units in a wide variety of applications and sectors, with its potential in the automotive sector in its current form likely to come from acting as a generator in a simple, low-cost, lightweight range-extender electric vehicle.

The reason the engine’s potential application is so wide, according to Andrews, is because it uses solely conventional components and no exotic materials or sealing processes.

The way it works is remaining confidential for now, but Andrews hints that the “self supercharging” comes from getting gases within the engine to flow and react in a different way, mimicking forced induction, and allowing freer breathing for the engine through its novel combustion architecture. 

Even before the components within the engine have been optimised, bench tests have shown it to be 20 per cent more powerful and suitably more economical over the Yamada diesel engine on which the unit is based. A further 10 per cent improvement is achievable, believes Andrews, through further optimisation of the parts. 

It currently runs on propane gas, but is very “fuel tolerant”, according to Andrews, and can run on a wide range of fuels including petrol, diesel, bio-ethanol and bio-methane.

The technology exists on a small one-cylinder unit at present, but can be adapted to multi-cylinder applications. 

“In this simple form, it can be used as a range extender to generate electricity in a small, low-cost, lightweight electric vehicle,” said Andrews. “It’s a lot closer to market than most novel engines due to its components. Exotic seals and materials are not needed, and it can be built on any existing production line using off-the-shelf components.”

Other potential applications Andrews sees for the engine include the ability to power generators to produce electricity for third-world villages, provide power to a small aircraft, provide power for taxis in polluted cities, and provide a cheap, efficient powertrain for vehicles including tuk-tuks.

Andrews says there is still “lots to do” with regards to developing the engine, but he is looking at “commercial opportunities” for it, with his preferred option to be to tie-up with a UK manufacturer to develop multiple versions of the powerplant.

The technology is one of several for range-extender vehicles presented at the Niche Vehicle Symposium in Gaydon today, an event organised by the Niche Vehicle Network, a Technology Strategy Board-backed group that supports niche vehicle and component suppliers in the UK. 


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Electric turbocharger and supercharger supplier Aeristech has shown off a compact supercharger that can provide a significant power boost to a Mahle-developed range-extender engine (taking it from 30kw to 50kw) to allow the drivetrain to power larger vehicles.

Other new range-extender technology comes from Advanced Innovative Engineering (AIE), which developed an exhaust expander unit to provide a 30 per cent power gain and 20 per cent reduction in emissions for a rotary wankel engine earmarked for use as a range extender without adding too much size and weight to the engine overall.

Mark Tisshaw

Title: Editor

Mark is a journalist with more than a decade of top-level experience in the automotive industry. He first joined Autocar in 2009, having previously worked in local newspapers. He has held several roles at Autocar, including news editor, deputy editor, digital editor and his current position of editor, one he has held since 2017.

From this position he oversees all of Autocar’s content across the print magazine, website, social media, video, and podcast channels, as well as our recent launch, Autocar Business. Mark regularly interviews the very top global executives in the automotive industry, telling their stories and holding them to account, meeting them at shows and events around the world.

Mark is a Car of the Year juror, a prestigious annual award that Autocar is one of the main sponsors of. He has made media appearances on the likes of the BBC, and contributed to titles including What Car?Move Electric and Pistonheads, and has written a column for The Sun.

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TBC 19 March 2014


A range extender running on E85 seems pretty good to me, although finding said fuel might be the biggest challenge....................
alanrandolf 18 March 2014

I suppose you could feasibly

I suppose you could feasibly make it work. But based on the rules, I'd doubt they'd let you run, even if the other 4 aren't combusting fuel.
fadyady 18 March 2014

Go for it, Andrews

In theory at least I am as fond of alternative fuels as the next person, but after having seen the current crop of electric cars (with the exception of the Model S and the i3) I'm beginning to feel a little bit short-changed and find it rather comforting that there is still life left in the internal combustion engine at least in conjunction with the battery.