The Dearman Engine operates by the vaporization and expansion of cryogenic fluids. Ambient or low grade waste heat is used as an energy source with the cryogen providing both the working fluid and heat sink. The Dearman Engine process involves the heat being introduced to the cryogenic fluid (liquid air or nitrogen) through direct contact heat exchange with a heat exchange fluid (HEF) (water and glycol) inside the engine. The HEF facilitates extremely rapid rates of heat transfer within the engine. This allows injection of the liquid cryogen directly into the engine cylinder whereupon heat transfer occurs via direct contact mixing with the HEF. The heat transfer on injection generates very rapid pressurization in the engine cylinder.

Direct contact heat transfer continues throughout the expansion stroke giving rise to a more efficient near-isothermal expansion. With the pressurization process taking place in the cylinder, the amount of pumping work required to reach a given peak cylinder pressure is reduced. After each expansion cycle the heat exchange fluid is recovered from the exhaust and reheated to ambient temperature via a heat exchanger similar to a conventional radiator.

In January, Dearman announced that it had completed its shakedown testing milestone at the end of 2013 at Imperial College, London, and was moving into a three-month program of tests and performance mapping. (Earlier post.)

Using the Dearman Engine allows efficient use of the waste heat, leading not only to greater economy, but also offering the potential for improved air quality. The technology uses readily-available materials with low embedded carbon, and operates with commercially-available liquid nitrogen, which is readily available and is frequently produced using off-peak electricity,with great potential for storing wrong-time renewables.

The IDP10-funded project will cost £3.25 million (US$5.46 million), £1.9 million (US$3.19 million) of which has come from the Technology Strategy Board grant. Dearman is working with MIRA, Air Products, Productiv, The Manufacturing Technology Centre, CENEX and TRL, bringing together expertise in the Dearman system, industrial gases, ICEs, vehicle systems, legislation and standards and manufacturing. The consortium will deliver an on-vehicle demonstration of the hybrid system over the next two years as well as engage the potential supply, demand and legislative chains.

Liquid air technologies have the potential to significantly reduce well-to-wheel emissions. This exciting project builds on a programme of activity already underway jointly with Dearman and it will validate the use of liquid nitrogen hydride powertrains in urban applications.

—Chris Reeves, Commercial Manager of Future Transport Technologies at MIRA

Liquid air and the Dearman Engine were recently recognised as a potential road transport energy vector by the European Road Transport Advisory Council (ERTRAC). (Earlier post.) ERTRAC is the European technology platform for the road transport industry and is seeking to deliver the accelerated development of sustainable, integrated transport solutions. Called “Energy Carriers for Powertrains”, the ERTRAC report seeks to establish a road map for how the industrialised countries of Europe and elsewhere can reduce the production of greenhouse gases in the road transport sector by up to 80% by 2050 when compared to 1990 levels.

The report identified liquid air as ”an adaptable energy vector which can be created and consumed using traditional mechanical engineering technologies, stored safely in un-pressurised containers, and made from a free abundant raw material.” The report adds that liquid air can be used in many applications to improve or replace existing transport solutions.

Zero emission applications as a primary source is certainly of interest in urban scenarios for light duty, short range applications. For heavy duty applications, it may provide opportunities for more efficient and cost effective waste heat recovery from internal combustion engines

—“Energy Carriers for Powertrains”

Other IDP10 awards. TSB made four other IDP10 awards. These are:

• About £2 million to a consortium led by Ariel Ltd. to develop a low-volume, ultra-high performance production sports car with zero and low emissions achieved through advanced hybrid technology to be built in low-volume using and expanding a UK technology-led supply-chain.

• About £2 million to a consortium led by Jaguar Land Rover. Jaguar Land Rover, in partnership with Ford Motor Company Ltd, European Thermodynamics Ltd and Nottingham University, will launch a 3-year program of research in which conventional concepts of engine management of thermal energy will be re-examined using advanced simulation tools, and a novel test engine which will allow the heat available to be directed to the most import components such as the cylinder liner walls.

  Some of the heat that will inevitably escape down the exhaust will be converted into electricity using a thermoelectric generator (TEG). In the longer term, if all the project targets are met, it is believed that a 5% improvement in fuel economy is possible through the conversion and management of heat energy. The project builds on an earlier TSB-funded project.

• £2.6 million (US$4.37 million) to a consortium led by Lotus Cars to accelerate the maturation of a mechanical flywheel energy storage system from Flybrid for use in a Lotus Evora road car. The integration of the flywheel into the manual gearbox will deliver a CO₂ reduction while increasing available power and torque. The project will accelerate the development of the Flywheel, electronic clutch, vehicle integration and control software by the consortium members to a production-intent status.

• £2.7 million (US$4.54 million) to a consortium led by Torotrak Ltd to research and develop an innovative supply chain processes for the production of key components. These components form part of a range of products that will support vehicle manufacturers to meet their obligations to reduce carbon emissions. The group will evaluate and develop the most appropriate steels that suit the innovative forging processes to ultimately reduce post processing and thus costs and the supply chain lead time. The outcome will then enable industry to exploit the new processes and therefore see the CO₂ reducing products into market to support the vehicle manufacturers.