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Combustion engine doubles thermal efficiency

A British firm claims to have designed an internal combustion engine with more than double the thermal efficiency of current high-performance models.

Sussex-based Ultramo says the engine will operate at around 70 per cent efficiency and if deployed worldwide could reduce carbon emissions by up to 21.5 per cent. Automobile engines typically have a 25 to 30 per cent efficiency rating, while large power plant engines can reach levels of more than 50 per cent.

Because the engine is designed to operate with a variety of fuels, it could be used with biofuels and hydrogen as these become more common and could be particularly useful for generating power in developing countries.

The idea behind Ultramo’s engine design is to capture the heat that is usually lost through the exhaust and cooling systems and using it as extra power, while maintaining a lower operating pressure.

While the company is keeping the design a closely guarded secret, managing director Chrissi Wilkins told The Engineer it involved removing the engine’s cooling system and converting the heat to movement.

‘This is entirely new thermodynamically,’ she said. ‘We’re not looking at using particularly high temperatures in our combustion process because of the emissions challenges it creates. The key thing is that we’re harnessing that heat.’

The company is exploring materials that can withstand higher temperatures for the working parts of the engine, but the lower operating pressure also means the machine will be under less stress and materials can be more lightweight.

‘With many concepts there’s a lot of compromise where you need to optimise the design for the best balance, but with this design as one characteristic gets better so many others improve,’ added Wilkins.

Ultramo is seeking £500,000 to build a prototype of the engine and has applied to the Carbon Trust’s Entrepreneurs Fast Track scheme. The South East England Development Agency (SEEDA) has approved a grant for the company but is due to be axed by the government.

Readers' comments (20)

  • Details, were are those ?

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  • As the author says, the company is 'keeping the design a closely guarded secret'.

  • They only filed their patent application (GB200918707) in December 2009 and somehow they expect people to get excited about mere claims. Interesting that there is a complete lack of comment on power density given that 70% efficiency isn't hard to achieve if you're happy for a quarter of your vehicle to be the engine. Also there is a suspicious absence of comment on the cost of the engine. There is not enough detail in this article to warrant interest.

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  • In the USA around the late 1970's or early 1908's there were a few compound vehicle engines built in which the heat that would otherwise be rejected was used in an organic Rankine cycle that substantially increased overall efficiency of conversion of heat to power. These added much weight and cost and were considered interesting but not commercializable.
    Is the current attempt to increase efficiency a similar heavy and expensive device?

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  • Without the first prototype is hard to set price. Problem is there are always givent money for grants, but no results at the end.....

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  • Ultra Large Temperature Ratio Motor (UltraMo).

    They might be trying to use a refrigerant instead of the regular coolant to boil it and pass it through a turbine. Then when the combustion piston expand, it compresses back the refrigerant.

    If it is just a small combined or binary cycle, then nothing new here.

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  • I doubt its possible. 70% efficiency is far higher than an oil or coal power station can achieve.

    A link to the application would be useful.

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  • Hello Dennis. You might find what you're looking for at this URL:

  • This is an exciting report and the potential appears enormous. But it falls into the category of numerous other sales orientated reports in The Engineer, basically they lack any detailed reports of their ACTUAL performance cost and overall operating cost. They also need other people's money to be viable.

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  • Thanks to the Editor for referring readers to our website which I hope will answer some of your questions.

    Some of you have mentioned power density, an important factor in engine design & development! Even at this early stage, we are forecasting a power density by volume equivalent to a diesel engine installation, whilst power density by weight is likely to be better than conventional technology.

    Steven also points out that if production costs are too high, the technology will not be commercialisable. ULTRaMo engines employ conventional engine materials and use proven engineering techniques - we do not therefore expect production costs to present a commercial problem.

    As a start-up business, passionate about opportunity, collaboration, and innovation, we welcome all interest and support. Thank you!

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  • to Chrissi Wilkins
    Can you please provide a link to your patent application.

    I doubt you will get much serious interest, at least in the private sector, without explaining the broad direction of your research.

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  • Weight and size are relatively uninportant for static power generation installations.
    Compound expansion and "bottoming" cycle engines with greatly inproved thermal efficiencies have been made in the past. The question is whether these engines can be made sufficiently durable and cost efficient to become a comercial proposition?

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