[sustran] Re: Fuel consumed by idling

[Madhav Badami, Prof.]

Re: the technical issue of idling before I sign off for the day ... I said that CO2 is strictly a function of fuel consumed. I was thinking about it, and it occurred to me that this would not be the case on two-stroke motorcycles for example, where as much as 30% of the fuel-air charge can escape unburned through the exhaust due largely to “mixture short-circuiting”. Perhaps I should have said "fuel burned" rather than "fuel consumed".

One other point ... As for the share of idling in trip fuel consumption and emissions, or for that matter, the share of trip-end (cold start and hot soak) emissions that Zvi Leve brought up, the situation is likely to be different in different contexts, on account of vehicle technology and driving cycle differences.

Madhav

************************************************************************

"As for the future, your task is not to foresee, but to enable it."
Antoine de Saint-Exupery
 
Madhav G. Badami, PhD
School of Urban Planning and McGill School of Environment
McGill University
Macdonald-Harrington Building
815 Sherbrooke Street West
Montreal, QC, H3A 2K6, Canada
 
Phone: 514-398-3183 (Work); 514-486-2370 (Home)
Fax: 514-398-8376; 514-398-1643
URLs: www.mcgill.ca/urbanplanning
www.mcgill.ca/mse
e-mail: madhav.badami at mcgill.ca




-----Original Message-----
From: sustran-discuss-bounces+madhav.g.badami=mcgill.ca at list.jca.apc.org on behalf of Zvi Leve
Sent: Thu 5/10/2007 10:44 AM
To: Global 'South' Sustainable Transport
Subject: [sustran] Re: Fuel consumed by idling
 
Also don't forget that "cold engines" (say in the first half-hour of 
use) emit significantly more pollutants (orders of magnitude more) than 
warm ones. If many buses (and trains) begin their routes at Kings Cross 
and are immediately stuck in congestion when trying to leave the area, 
then that would be a particularly bad situation!

Zvi

Madhav Badami, Prof. wrote:
> Martin Cassini wrote: "I thought I said, and meant, that 40% of polluting gases from traffic, not fuel used, is from traffic idling.", and then asked about CO2.
>
> I will have to check on the share of idling in emissions of various "criteria" air pollutants in city driving, but as far as CO2 is concerned, the share of idling in CO2 emissions must be the same as its share in fuel consumption, since CO2 is strictly a function of how much, rather than how, the fuel is burnt.
>
> Madhav
>
> ************************************************************************
>
> "As for the future, your task is not to foresee, but to enable it."
> Antoine de Saint-Exupery
>  
> Madhav G. Badami, PhD
> School of Urban Planning and McGill School of Environment
> McGill University
> Macdonald-Harrington Building
> 815 Sherbrooke Street West
> Montreal, QC, H3A 2K6, Canada
>  
> Phone: 514-398-3183 (Work); 514-486-2370 (Home)
> Fax: 514-398-8376; 514-398-1643
> URLs: www.mcgill.ca/urbanplanning
> www.mcgill.ca/mse
> e-mail: madhav.badami at mcgill.ca
>
>
>
>
> -----Original Message-----
> From: sustran-discuss-bounces+madhav.g.badami=mcgill.ca at list.jca.apc.org on behalf of martincassini at blueyonder.co.uk
> Sent: Thu 5/10/2007 7:26 AM
> To: Global 'South' Sustainable Transport
> Subject: [sustran] Re: Fuel consumed by idling
>  
> Given a green light (!) for the film and/or TV programme / series that I'm
> planning, there will be the opportunity to research and establish these
> and other facts and figures. One question: why are g/km (CO2 per
> kilometre) figures published but not g/pm (CO2 per minute engine
> running/idling)? Even the manufacturers don't seem to know.
>
> Martin
>
>   
>> I still have trouble with that figure â?"  would love to see a clear,
>> published, written reference where
>> we can see the sources, assumptions, and numbers crunched. And of
>> course, let us know which gases!
>>
>>     
>>>>> <martincassini at blueyonder.co.uk> 5/10/2007 5:54:26 AM >>>
>>>>>           
>> I thought I said, and meant, that 40% of polluting gases from traffic,
>> not
>> fuel used, is from traffic idling. I got that figure from
>> pro-regulation
>> man Prof David Begg. As you might have read, chronic lung disease and
>> malformations occur in children who live on or near main roads. My
>> lung
>> function has suffered since I moved to King's Cross. On the Euston
>> Road, I
>> see catastrophic congestion every day of the week, caused largely by
>> an
>> endless procession of mandatory traffic lights, permanent bus lanes,
>> and
>> the congestion charge which forces vehicles on to outer routes.
>>     
>>> Please cite sources for the claim that 40% of fuel is used from
>>> idling. I suspect that it is a misinterpretation of the data. A
>>> typical vehicle consumes about a tenth as much fuel per unit of time
>>> while idling as under load (typically about 1 liter per hour for a
>>> car and 2 liters an hour for a large truck). If an average vehicle
>>>       
>> is
>>     
>>> driven 1 hour per day and idles 5 minutes, idling represents about
>>>       
>> 1%
>>     
>>> of total fuel consumption.
>>>
>>> I think Cassini may be confusing idling with stop-and-go driving
>>> conditions, but I'm skeptical that the traffic management strategies
>>> he advocates would actually increase traffic efficiencies. I think
>>> there is a good case for converting stop signs and signal
>>> intersections to roundabouts, but I've yet to see evidence that
>>> eliminating traffic controls altogether ("naked streets") reduces
>>> delay or crash risk overall in most situations.
>>>
>>> There are many anti-idling campaigns underway, but most seem to
>>> exaggerate the benefits, they are an excuse to avoid the more
>>> critical reforms needed to reduce economically excessive vehicle
>>> travel and associated social costs (see
>>>       
>> http://www.vtpi.org/wwclimate.pdf
>>     
>>> ).
>>>
>>>
>>> Best wishes,
>>> -Todd Litman
>>>
>>>
>>> At 10:42 AM 5/6/2007, Martin Cassini wrote:
>>>       
>>>> Dashing out, but in the UK, about 30% of our CO2 output is from
>>>>         
>> traffic.
>>     
>>>> Prof David Begg admits that 40% of that is from traffic idling. How
>>>> often does traffic idle at lights for no good reason? I live in
>>>>         
>> King's
>>     
>>>> Cross, and I would say a good (or bad!) half the time. Also you have
>>>>         
>> to
>>     
>>>> add the cost of manufacturing, installing, maintaining and RUNNING
>>>>         
>> the
>>     
>>>> galaxy of 24-hour lights - this alone represents a massive carbon
>>>> footprint. If it wasn't for the lights, traffic would filter and
>>>>         
>> flow,
>>     
>>>> instead of continually stop, idle and re-start. Traffic volume can be
>>>>         
>> a
>>     
>>>> drama, but volume + controls = crisis.
>>>>
>>>> Martin
>>>>         
>>> Sincerely,
>>> Todd Alexander Litman
>>> Victoria Transport Policy Institute (www.vtpi.org)
>>> litman at vtpi.org
>>> Phone & Fax 250-360-1560
>>> 1250 Rudlin Street, Victoria, BC, V8V 3R7, CANADA
>>> "Efficiency - Equity - Clarity"
>>>
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