Idle (engine)

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This article is about engine idle. For other uses, see Idle (disambiguation).

Idling is running a vehicle's engine when the vehicle is not in motion. This commonly occurs when drivers are stopped at a red light, waiting while parked outside a business or residence, or otherwise stationary with the engine running. When idling, the engine runs without any loads except the engine accessories.

Idling Myths

[1]

  • Myth: restarting the engine uses more gas than idling. Reality: an engine restart uses fuel approximately equal to 10 seconds of idling.
  • Myth: restarting the engine causes greater engine wear than idling. Reality: restarting causes less.
  • Myth: cars need to idle to warm up the engine. Reality: the engine warms up faster when being driven.

Idling Vehicle Emissions

Engine idling produces several pollutants that are monitored by the Environmental Protection Agency (EPA):[2]

Winter Conditions (30°F, 13.0 psi RVP gasoline)

Pollutant LDGV LDGT HDGV LDDV LDDT HDDV MC
VOC [g/min] 0.352 0.512 0.734 0.061 0.080 0.211 0.335
CO [g/min] 6.19 8.12 11.4 0.168 0.191 1.58 6.47
NOx [g/min] 0.103 0.125 0.196 0.111 0.115 0.945 0.042

Summer Conditions (75°F, 9.0 psi RVP gasoline)

Pollutant LDGV LDGT HDGV LDDV LDDT HDDV MC
VOC [g/min] 0.269 0.401 0.597 0.059 0.077 0.208 0.324
CO [g/min] 3.82 5.65 12.3 0.166 0.187 1.57 7.26
NOx [g/min] 0.079 0.095 0.170 0.108 0.111 0.917 0.028
[3]

Health Effects of Idling Pollutants

Acute Effects

[4][5]

  • Direct contact effects: eye, throat, and bronchial irritation
  • Neurophysiologic: nausea, lightheadedness
  • Respiratory: cough, phlegm congestion
  • Immunologic: allergic or asthma-like respiratory response
  • Cardiovascular: increased risk for cardiac events

Chronic Effects

[6][7]

  • Chronic bronchitis
  • Decreased lung function
  • Animal studies show strong dose-related effects of inflammation and cellular changes
  • Likely carcinogenic (cancer-causing) via inhalation: including lung, bladder, lymphatic, testicular, gastrointestinal, and prostate cancers
  • Reproductive: links to low birth weight and damage to sperm chromatin and DNA.[8]

These health effects are more damaging in those with preexisting heart disease, asthma, or other lung problems. Children are also more susceptible, due to their faster breathing rate and the fact that their respratory system is still developing. Idling pollutants also disproportionately affect the elderly, who have limited physiological reserve to compensate for the adverse effects of the pollutants.[9]

Strategies to Reduce Idling

Effort has been made to reduce the amount of time engines spend idling, chiefly due to fuel economy and emissions concerns, although some engines can also be damaged if kept idling for extended periods. In the United States, about a billion gallons (3.8 billion liters) of fuel is consumed by idling heavy-duty truck and locomotive engines each year.[10] Many newer semi-trucks have small auxiliary power units (APUs) to run accessories more efficiently while the truck is parked. Hybrid vehicles typically shut down their internal combustion engines while stopped, although some conventional vehicles are also including start-stop systems to shut off the engine when it would otherwise idle.

Federal level

Both the Department of Energy and the Environmental Protection Agency have programs in place to reduce idling. The DOE is funding research and development for alternative and advanced vehicles, which includes the gathering of quantitative data on medium-duty trucks, examining idling reduction alternatives, and the CoolCab project for semi-truck curtains and installation.[11] The EPA's programs include the Environmental Technology Verification Program,[12] the Smart Way Transport Partnership (freight incentives), the Model State Idling Law (diesel) and Clean School Bus USA.[13]

State level

All but 11 states have at least one incentive or law in place to reduce idling, while 7 states have at least four.[14] The state of Colorado has in place a tax credit for alternative fuel and qualified idle reduction technologies, as well as the Green Truck Grant Program which allows the Governor's Energy Office to provide reimbursement of up to 25% of costs to owners of commercial trucks used in interstate commerce to reduce emissions.[15]

Local level

There are many local ordinances and programs to discourage idling, such as ordinances limiting the minutes per hour in which a vehicle can idle.[16] One example of a local program is Denver, Colorado's Engines Off! city-wide anti-idling campaign, which aims to improve air quality and reduce greenhouse gas emissions by promoting voluntary behavior change in idling behavior.[17]

See also

References

  1. ↑ Environmental Defense Fund. (2008) Attention Drivers! Turn Off Your Idling Engines. Accessed at http://www.edf.org/transportation/reports/idling.
  2. ↑ United States Environmental Protection Agency. Emission facts: idling vehicle emissions. April 1998. Accessed at http://www.epa.gov/oms/consumer/f98014.pdf
  3. ↑ United States Environmental Protection Agency. Emission facts: idling vehicle emissions. April 1998. Accessed at http://www.epa.gov/oms/consumer/f98014.pdf
  4. ↑ U.S. Environmental Protection Agency (EPA). (2002) Health assessment document for diesel engine exhaust. Prepared by the National Center for Environmental Assessment, Washington, DC, for the Office of Transportation and Air Quality; EPA/600/8-90/057F. Available from: National Technical Information Service, Springfield, VA; PB2002-107661, and <http://www.epa.gov/ncea>.
  5. ↑ HEI Panel on the Health Effects of Traffic-Related Air Pollution. (2010) Traffic-Related Air Pollution: A Critical Review of the Literature on Emissions, Exposure, and Health Effects. HEI Special Report 17. Health Effects Institute, Boston, MA.
  6. ↑ U.S. Environmental Protection Agency (EPA). (2002) Health assessment document for diesel engine exhaust. Prepared by the National Center for Environmental Assessment, Washington, DC, for the Office of Transportation and Air Quality; EPA/600/8-90/057F. Available from: National Technical Information Service, Springfield, VA; PB2002-107661, and <http://www.epa.gov/ncea>.
  7. ↑ HEI Panel on the Health Effects of Traffic-Related Air Pollution. (2010) Traffic-Related Air Pollution: A Critical Review of the Literature on Emissions, Exposure, and Health Effects. HEI Special Report 17. Health Effects Institute, Boston, MA.
  8. ↑ Calogero A.E. et al. Environmental car exhaust pollution damages human sperm chromatin and DNA. Journal of Endocrinological Investigation (2011). 34;E139-E143
  9. ↑ http://www.hcdoes.org/airquality/anti-idling/bushealth.htm
  10. ↑ U.S. Environmental Protection Agency (EPA). "Idling Reduction." SmartWay Transport.
  11. ↑ U.S. Department of Energy. Alternative and advanced vehicles. (2011) http://www.afdc.energy.gov/afdc/vehicles/idle_reduction_research.htm
  12. ↑ United States Environmental Protection Agency. Environmental technology verification program.(2012) http://www.epa.gov/nrmrl/std/etv/center-apc.html
  13. ↑ United States Environmental Protection Agency. Smart way.(2011) http://www.epa.gov/smartway/basic-info/index.htm
  14. ↑ U.S. Department of Energy. Idle reduction incentives and laws. (2011) http://www.afdc.energy.gov/afdc/vehicles/idle_reduction_laws.html
  15. ↑ U.S. Department of Energy. Colorado incentives and laws for idle reduction. http://www.afdc.energy.gov/afdc/progs/ind_state_laws.php/CO/IR
  16. ↑ Denver the Mile High City. Idling vehicles. (2011) http://www.denvergov.org/OutdoorAirQuality/SmokingIdlingVehicles/tabid/424914/Default.aspx
  17. ↑ Engines off! Denver. Engines off! Denver. (2008) http://enginesoff.com/index.html
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