Project Highlights

  • Energetics worked with Argonne National Laboratory on a technical analysis project to examine how frequent on–off cycles for idle reduction affect a vehicle’s starting system.

  • Energetics determined that normal cycles of turning an engine off and back on would not shorten the life of the starting system. Most drivers can turn the engine off if they are going to be stationary for more than two minutes without incurring any significant repair costs.

Argonne National Laboratory’s idle reduction team had identified a common belief that drivers would wear out their starters if they turned their engines off while standing, for example, in a parking lot or school pick-up area. Because idling wastes fuel and creates emissions, the idle reduction team was interested in determining what, if any, detrimental effects frequent use of the starter would have. The purpose was to recommend to consumers a course of action that would save fuel.

Energetics gathered technical information from vehicle manufacturers and literature searches to quantify the economic effects of frequently starting a vehicle engine. Our technical experts developed estimates of failure potential for starters and batteries for vehicles based on the number of cycles (for starters) or the time between cycles (for batteries). A simple economic model estimated the increased potential for component failure (starter or battery), then balanced that potential against the fuel cost savings from shutting down the engine. A detailed technical report presented the information to Argonne, describing the analysis and results for a technical audience.

The analysis determined that most normal start–stop cycles (fewer than ten starts per day) would not have a detrimental effect on the starting system life, as the systems are designed for this duty cycle. Shutdowns of more than one minute will begin saving the consumer money in fuel costs without creating starter life issues. This report was the first of its kind, using technical analysis supported by industry inputs to address the long-standing objection to controlling idling through engine shutdown.


Ziga Ivanic
Program Director, Transportation Technologies
Phone: 410-953-6261

Other staff: Paul Windover, Russ Owens