Improvement of fuel economy and vehicle performance through pneumatic regenerative engine braking device (Reneged)

Over the last few years, a new and cost-effective pneumatic regenerative engine braking (RegenEBD) concept has been researched and developed in order to improve the fuel economy of inner city buses. The RegenEBD concept is realised by swapping a standard engine braking device from the exhaust side to the intake side and implementing a proprietary one-way intake design. The engine is operated as a compressor during the vehicle deceleration through the action of RegenEBD so that the vehicle's kinetic energy can be converted into pneumatic energy in the form of compressed air. Regenerative stop-start can then be realised through the use of a standard air starter motor. In this paper, the prototype RegenEBD engine and bus are first presented. This is followed by a discussion on the engine testing results and preliminary bus driving tests. Experimental results show that the fuel economy can be improved by 5-10 % for inner city buses, and there is potential for improved vehicle performance through instant boost by the regeneratively produced compressed air.