The prevention of leaving the engine running on a vehicle when it is stationary is shown to have potential for reducing fuel consumption and emissions. Data were obtained for carbon dioxide and nitrogen oxides emission for a 1998cc diesel engine and a 1497cc gasoline engine idling for 2-120s. There was a marked increase in emissions on the restarting of a stationary vehicle. In terms of emissions, the benefit of turning off the engine while idle was achieved after 40s in the diesel vehicle and after 180s in the gasoline vehicle but would depend on the characteristics of the specific vehicle. A system is proposed that would detect the red phase of the traffic signal cycle and how long it would last, in order to turn off the engine if appropriate.
Abstract