Dear All,
looking through the information on idling, including many of the links that have been supplied in these forums by other members in the past, I cannot help but notice that while many sites proclaim to dispel the 'idling myths', there is virtually no (I yet have to find one) reference to primary studies. I very much would encourage members of this site to share your knowledge about studies (and the sources - the journal or the agency that published a report), which actually provide the numbers for the much-cited conclusion that idling a)wastes petrol and b) reduces the engine component longlevity. Also, Doug mentioned during a workshop I attended just yesterday that switching off the engine if the better choice if you would idle for longer than 10 seconds. Is there concrete information whether this is the case for a) all vehicle types, b) all fuel types, c) all types of weather.
It would be great if we could gather information on this and the site administrator could put these into a link compendium elsewhere on the site as data link repository for idling research.
Best from Melbourne,
Felix
Felix Acker
LaTrobe University
Australia
Idling Research
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Dear George,
thank you for the material. If I read it correctly, then the only study that looked at emissions during idling verus hotsoak is the Canadian one you attached. Looking at their data and plotting this as a curvilinear regression, it appears to me that for periods of 10 seconds or less idling is better. More importantly, though, for longer periods (up to 10 minutes of continuous idling) the amount of emissions is more or less the same (different in absolute numbers but not different enough to claim that this is a systematic difference and not just measurement error). Also, according to the other summary article you posted, switching the engine off does, in fact, cause wear on starters and other components, contrary to what is often read on anti-idling websites. The only real reason not to idle is that it uses more petrol and hence it is mainly an economic concern and secondary an environmental concern in terms of the resources required to get extra petrol from the groung into the car.
Overall, then, there is no compelling argument to be made to tell anybody not to idle, at least not in situations such as city traffic. I find this rather surprising and would hope that we can find some more research with further data.
Best from Melbourne,
Felix
Felix Acker
Research & Statistics Officer
Bicycle Victoria
Australia
Reference #1 for Env Can really should not be used to credit/discredit idling reduction programs. The intent was to evaluate tailpipe emissions after either idling or soaking. That fact aside, and despite only 3 vehicles being tested, only CO showed a negative for soaking.
Reference #2, reading the Exec Summ seems to clearly indicate that idling is worse than soaking, save maybe the very last bullet in the Exec Summ. Not a convincing case to idle.
One thing to keep in mind, if the vehicle is left running, and you assume there are zero hot soak emissions, you are forgetting about running losses. When the fuel system is under high pressure, any little leak or loose connection is exploited. Numerous studies in the US/CA have found that running losses can be huge, much more than hot soak. This is especially true for ethanol blends in non flex-fuel equipped autos.
Finally, though it is clear that heavy-duty vehicles need to prevent idling, all drivers should be made to realize the benefits of not idling. Wasted fuel is wasted fuel. Emissions, even if less than 5% of the vehicle total, are significant. If I told you that I could improve air quality 5% this year, would you think that was great news? Food for thought.
See this DOE study for truck idling fuel consumption, which captures light duty trucks as well. There are some published on-board emissions monitoring systems (OEMS) studies out there that look at real-time monitoring of indiviudal vehicles. That is the future.
Gregg Thomas
United States
I look at idling, whether it be from a passenger car to a diesel truck, as an environmental problem FIRST and an economic concern last. Heres why:
1. One minute of idling produces more carbon monoxide than smoking three packs of cigarettes.
2. Ford Motor company says: Avoid idling more than 30 seconds (when not in traffic), frequent restarting has little impact on the battery and starter (About $10.00 a year worth of wear), whereas excessive idling can actually damage important engine components.
3. Reducing diesel exhaust emissions can make a significant contribution to cleaner air.
Idling fuel use is approximately 0.6 Liters per hour per Liter of engine displacement.
Source: Review of the Incidence, Energy Use and Costs of Passenger Vehicle Idling.
Office of Energy Efficiency, Natural Resources Canada, 2003. (They tested numerous vehicles to come up with an estimate of idling fuel use per Liter of engine displacement.)
This is equal to 0.1585Gal/hr/L of Engine Displacement
1Gallon = 3.785 Liters
5 min x 365 days = 30.4 hours
Some examples of idling fuel use per hour, and resulting annual fuel use from 5 minutes per day of idling:
Vehicle model Engine displacement Fuel use per hr. of idling Annual use
Honda Fit 1.5L 0.24 gal 7.3 gal
Ford Focus 2L 0.32 gal 9.6 gal
Ford Explorer 4L 0.63 gal 19.2 gal
Ford Expedition 5.4L 0.86 gal 26.1 gal
Ford F-350 6.8L 1.08 gal 32.8 gal
The numbers that NRC came up with match what others sources say as well--about 1/3 gal/hr for small cars, up to 0.75gal/hr for trucks/SUVs, and 1 gal/hr for larger/commercial trucks. (Here is a site with similar estimates, for example: http://www.thehcf.org/antiidlingprimer.html)
From what Ive been told pretty much everything holds true for diesels, certainly the fuel use estimate. (The cigarette comparison is an estimate for a regular passenger car, so a larger vehicle would be more). The Fords (and others) 30 second rule is for passenger vehicles, not big trucks/buses, but should not be significantly different for a warmed up diesel engine. Below is a quote from Caterpillar, which is pretty identical to what the other Truck/bus/diesel-engine manufactures say. Heavy Duty Trucking Magazine recommended that Truckers turn their engines off waiting for trains and even at long red lights (!!we dont recommend that). So it might be a 45second or 1 minute rule for a small diesel or something slightly different if someone really did the calculations, but it should be safe to say that a Dodge Ram certainly shouldnt need to idle more than a semi truck.
Go to Google and type in Brown cloud Denver. Gross, no? 2% of the vehicles in Denver are diesel. Diesel exhaust contributes 15-23% of the fine particle-matter pollution in the entire region. This nastiness in our air causes respiratory problems in the young, elderly, and those with pre-existing aliments. 25-40% of the brown cloud comes from diesel exhaust.
From the Caterpillar Motor Coach Engine Performance Guide:
A diesel engine consumes approximately 1 gallon of fuel per hour at a fast idle (900 1000 RPM). Idling consumes valuable resources (fuel) and for the most part is unnecessary. Excessive idling can contribute to carbon build-up and / or engine slobber and is detrimental to the engine.
Engine Warm-up The best and fastest way to warm-up an engine is to begin driving at part load and part throttle shortly after start-up, following a brief inspection of the coach.
Engine Shut-down Before exiting the highway, take your foot off the throttle and coast long enough to decelerate the coach to the point where a minimum amount of braking is required to exit the main roadway. A heavy coach can coast a long distance with the drivers foot off the throttle. During the coasting period the engine is not consuming any fuel. With a light load on the engine for a period of two to three minutes, the engine has cooled sufficiently and can be shutdown.
Thanks Matthew!
Tiffany Rice
Superhero of anti-idling
United States
Hi Felix,
I too was looking for the same information two years ago.
The following reports have some information --
1. Environment Canada, Environmental Technology Centre, Emissions Research and Measurement Division. Effect of Hot Soak/Idle Period on Exhaust Emissions and Fuel Consumption. ERMD Report #00-41.
2. Natural Resources Canada, Office of Energy Efficiency. Review of the Incidence, Energy Use and Costs of Passenger Vehicle Idling.
They are attached for your reference. Hopefully this helps.
Cheers.
George Kamiya
YVR
Canada