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Accession Number DE2013-1060966
Title Quantifying the Effects of Idle-Stop Systems on Fuel Economy in Light-Duty Passenger Vehicles.
Publication Date Dec 2012
Media Count 32p
Personal Author J. Wishart M. Shirk
Abstract Vehicles equipped with idle-stop (IS) systems are capable of engine shutdown when the vehicle is stopped and rapid engine restart for the vehicle launch. This capability reduces fuel consumption and emissions during periods when the engine is not being utilized to provide propulsion or to power accessories. IS systems are a low cost, fast growing technology in the industry wide pursuit of increased vehicle efficiency, possibly becoming standard features in European vehicles in the near future. In contrast, currently there are only three non-hybrid vehicle models for sale in North America with IS systems and these models are distinctly low volume models. As part of the United States Department of Energy's Advanced Vehicle Testing Activity, ECOtality North America has tested the real world effect of IS systems on fuel consumption in three vehicle models imported from Europe. These vehicles were chosen to represent three types of systems: (1) spark ignition with 12-V belt alternator starter; (2) compression ignition with 12-V belt alternator starter; and (3) direct injection spark ignition, with 12-V belt alternator starter/combustion restart. The vehicles have undergone both dynamometer and on-road testing; the test results show somewhat conflicting data. The laboratory data and the portion of the on-road data in which driving is conducted on a prescribed route with trained drivers produced significant fuel economy improvement. However, the fleet data do not corroborate improvement, even though the data show significant engine-off time. It is possible that the effects of the varying driving styles and routes in the fleet testing overshadowed the fuel economy improvements.
Keywords Alternators
Engine idling
Fuel consumption
Fuel economy
Idle-stop(IS) systems
Internal combustion engines
Passenger vehicles
Spark ignition engines

Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 97K - Fuels
81A - Combustion & Ignition
81J - Reciprocation & Rotating Combustion Engines
85H - Road Transportation
Corporate Author Idaho National Laboratory, Idaho Falls, ID.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1321
Contract Number DE-AC07-05ID14517

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