“Vehicle-specific power”的意思、由来-开放百科全书

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Vehicle-specific power

释义

Formulae
References
Cross-reference Sources used
Further reading

The concept of vehicle-specific power (VSP) is a formalism used in the evaluation of vehicle emissions. The idea was first developed by J. L. Jiménez {{harv|Jiménez|1998}} at the Massachusetts Institute of Technology.{{sfn|NAP2001|p=108}}{{sfn|NAP2000|p=184}} Informally, it is the sum of the loads resulting from aerodynamic drag, acceleration, rolling resistance, and hill climbing, all divided by the mass of the vehicle.{{sfn|NAP2001|p=108}} Conventionally, it is reported in kilowatts per tonne,{{sfn|NAP2001|p=108}} the instantaneous power demand of the vehicle divided by its mass.{{sfn|NAP2000|p=184}} VSP, combined with dynamometer and remote-sensing measurements, can be used to determine vehicle emissions.{{sfn|NAP2000|p=184}}

The United States Environmental Protection Agency held a "modelling shootout" in 2001, to help with the development of its (then) new MOVES (motor vehicle emissions simulator) vehicle emissions model. Two of the four modelling metholodogies in the shootout, one from North Carolina State University {{harv|Frey|2002}} and one internal to the EPA, used vehicle-specific power metrics.{{sfn|Barth|Younglove|Scora|2005|p=10}}{{sfn|Huai|Durbin|Younglove|Scora|2005|p=9595}} MOVES was eventually implemented using vehicle-specific power as its primary metric.{{sfn|Huai|Durbin|Younglove|Scora|2005|p=9595}} (See {{harvnb|Koupal|Cumberworth|Michaels|Beardsley|2002|loc=§ 7.1.3.1}} for the EPA MOVES draft VSP specification.)

Formulae

Jiménez' own formula is:

{{harv|Jiménez|McLintock|McRae|Nelson|1999}}

VSP can be simplified using typical coefficient values. Haibo Zhai of North Carolina State University provides the following formula for transit buses:

{{math|1=VSP = v × (a + g × sin φ + ψ) + ζ × v³}}{{sfn|Zhai|2007|p=56–57}}

where:

v: vehicle speed (in metres per second)

a: vehicle acceleration (in metres per second per second)

g: acceleration due to gravity (gee, in metres per second per second)

ϕ: road grade

ψ: rolling resistance coefficient (metres per second per second)

ζ: drag coeficient (reciprocal metres)

References

Cross-reference

Sources used

{{cite book|ref=CITEREFNAP2000|title=Modeling mobile-source emissions|series=Compass series|author=National Research Council Committee to Review EPA's Mobile Source Emissions Factor (Mobile) Model|publisher=National Academies Press|year=2000|isbn=978-0-309-07088-1}}
{{cite book|ref=CITEREFNAP2001|title=Evaluating vehicle emissions inspection and maintenance programs|author=National Research Council Committee on Vehicle Emission Inspection and Maintenance Programs|publisher=National Academies Press |date=1 November 2001 |isbn=978-0-309-07446-9}}
{{Cite journal|ref=harv|last1=Barth|first1=Matthew|last2=Younglove|first2=Theodore|last3=Scora|first3=George|year=2005|title=Development of a Heavy-Duty Diesel Modal Emissions and Fuel Consumption Model|work=California Partners for Advanced Transit and Highways (PATH)|url=http://escholarship.org/uc/item/67f0v3zf}}
{{cite journal|ref=harv|title=Vehicle Specific Power Approach to Estimating On-Road NH₃ Emissions from Light-Duty Vehicles|first1=Tao|last1=Huai|first2=Thomas D.|last2=Durbin|first3=Ted|last3=Younglove|first4=George|last4=Scora|first5=Matthew|last5=Barth|first6=Joseph M.|last6=Norbeck|journal=Environmental Science and Technology|year=2005|volume=39|pages=9595–9600|url=http://cichlid.cert.ucr.edu/research/pubs/6.pdf|format=PDF|doi=10.1021/es050120c|bibcode=2005EnST...39.9595H}}
{{cite book|ref=harv|title=Regional on-road mobile source emissions characterization for conventional and alternative vehicle technologies|first=Haibo|last=Zhai|publisher=ProQuest|year=2007|isbn=978-0-549-54985-7}}

Formulae

References

Cross-reference

Sources used

Further reading