E-MAIL
Brunel University"s School of Engineering and Design recently announced groundbreaking results from simulations which suggest a normal combustion engine can be adapted into a new air hybrid engine at very low cost. The resulting new air hybrid engine would be considerably cheaper to run and deliver significantly less carbon emissions. It may be used on Chinese buses in due course.
The idea is that using the engine"s compression to brake the vehicle, not only could slow the vehicle down, but also the pistons could compress air and drive it into a compressed air tank. It could then be used later to briefly power the piston and to provide compressed air for turbo charging during a period of turbo lag (normally at low revolutions).
Yuchai Air Hybrid Engine
For the last ten years, engineers have been attempting to transform an existing combustion engine into an air (pneumatic) hybrid. It was based on the theory of using electro-magnetic or electro-hydraulic valves to open and close the intake in the exhaust valve which is proving costly.
Brunel University has run simulations which require only small alterations to adapt a normal combustion engine into an air hybrid engine using production technologies. The simple and very cost effective solution needs no transmission alteration or engine redesign. The university’s air hybrid system is based on regenerative engine braking stop/start technology developed by a team of academics in Brunel’s Centre for Advanced Powertrain and Fuels. It is claimed to be more efficient than an electric stop/start system and can lead to better vehicle performance.
The simulations were successful and now Brunel is looking for OEM"s of bus and light utility vehicles to test the new engine.
Brunel University recently announced the signing of a technology development and licensing deal with Guangxi Yuchai Machinery Company that could see the its air hybrid system installed on buses throughout China. Guangxi Yuchai is the largest diesel engine manufacturer in China and supplies 70 per cent of the Chinese bus engine market.
The air hybrid system has some additional advantages. It can minimise the use of the engine-driven air compressor on buses resulting in further fuel saving and reduced maintenance. When installed on a city bus, the system is expected to produce a 10 per cent fuel economy benefit. Unlike an electric hybrid system, the Brunel air hybrid system can be added on to production engines and will work with existing transmission systems. The Brunel technology is also attracting interest from parties in the US and India.
The Brunel-Guangxi Yuchai team is currently developing a prototype of the air hybrid system. A demonstration vehicle will then be built to highlight the economic and environmental benefits to Chinese bus operators ahead of expected mass production.