Table of Contents
International Journal of Vehicular Technology
Volume 2013 (2013), Article ID 391650, 14 pages
Research Article

Fuel Efficiency by Coasting in the Vehicle

1School of Mechanical and Automotive Engineering, Kingston University of London, London SW15 3DW, UK
2Jaguar Land Rover, Banbury Road, Gaydon, Warwickshire CV35 ORR, UK

Received 19 March 2013; Accepted 4 July 2013

Academic Editor: Rakesh Mishra

Copyright © 2013 Payman Shakouri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper investigates the possibility of improving the fuel efficiency by decreasing the engine speed during the coasting phase of the vehicle. The proposed approach is stimulated by the fact that the engine losses increase with the engine speed. If the engine speed is retained low, the engine losses will be reduced and subsequently the tractive torque will be increased, enabling the vehicle to remain moving for longer duration while coasting. By increasing the time period of the coasting the fuel efficiency can be increased, especially travelling downhill, since it can benefit from the kinematic energy stored in the vehicle to continue coasting for a longer duration. It is already industry standard practice to cut fuel during coasting and refuel at low engine speed. The substantial difference proposed in this paper is the controlled reduction of engine speed during this phase and thus reduction in the engine losses, resulting in improved fuel economy. The simulation model is tested and the results illustrating an improvement to the fuel efficiency through the proposed method are presented. Some results of the experimental tests with a real vehicle through the proposed strategy are also presented in the paper.