That would be 20 J/m.
--- On *Fri, 9/18/09, lps /<[email protected]>/* wrote:
From: lps <[email protected]>
Subject: [USMA:45837] Re: Fuel efficiency – joules per metre
To: "U.S. Metric Association" <[email protected]>
Cc: "U.S. Metric Association" <[email protected]>
Date: Friday, September 18, 2009, 8:15 PM
My bicycle expends an average of 20 kJ/km
or
0.02 J/m (best for comparison with cars)
or
(Help me here) 20 mJ/m (yes miliJoules)
My battery is a 20 A*h 36 volt battery (LiFeO2).
Pat Naughtin wrote:
> On 2009/09/19, at 08:36 , lps wrote:
>
>> You can use J/m with electric cars too. I use the figure with
my electric bicycle. I convert w*h/ km to J/km. You can convert
that to J/m if desired.
>
> Dear Linus,
>
> Thanks for your email. I would like to make two points:
>
> 1 Could you share with us some of your data in joules per metre
for your electric bicycle so that we can make comparisons with
other vehicles. Where does your electric bicycle fit on this scale?
>
> Car 3 200 J/m
> Boeing 747 5 440 J/m
> School bus 13 510 J/m
> Truck 15 440 J/m
>
> 2 I think that it is preferred practice in SI to have the
denominator in a unit without a prefix and to apply any prefix to
the numerator. In this case, kilojoule per metre (kJ/m) would be
preferred to joules per kilometre (J/km). However, that said, I
believe that the simplest SI unit applied with whole numbers is
the best possible solution.
>
> Cheers,
> Pat Naughtin
> Author of the ebook, /Metrication Leaders Guide,/ that you can
obtain from
http://metricationmatters.com/MetricationLeadersGuideInfo.html PO
Box 305 Belmont 3216,
> Geelong, Australia
> Phone: 61 3 5241 2008
>
> Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to
the modern metric system smoothly, quickly, and so economically
that they now save thousands each year when buying, processing, or
selling for their businesses. Pat provides services and resources
for many different trades, crafts, and professions for commercial,
industrial and government metrication leaders in Asia, Europe, and
in the USA. Pat's clients include the Australian Government,
Google, NASA, NIST, and the metric associations of Canada, the UK,
and the USA. See http://www.metricationmatters.com
<http://www.metricationmatters.com/>
<http://www.metricationmatters.com/>for more metrication
information, contact Pat at [email protected]
<http://us.mc824.mail.yahoo.com/mc/[email protected]>
<mailto:[email protected]
<http://us.mc824.mail.yahoo.com/mc/[email protected]>>
or to get the free '/Metrication matters/' newsletter go to:
http://www.metricationmatters.com/newsletter to subscribe.
>
>> Pat Naughtin wrote:
>>> Dear All,
>>>
>>> I have just read the article at
http://www.metrication.us/content/demise-mpg where I was struck by
the first paragraph.
>>>
>>> /Even before the advent of partially- or fully-electric cars,
it was becoming increasingly apparent that the old fuel economy
metric of miles per gallon isn't as useful for measuring energy
consumption in vehicles as when it was first codified in the
original Corporate Average Fuel Economy standard in the 1970s.
That is due in part to the proliferation of new fuels--E85, LPG,
LNG, CNG, methanol, and hydrogen--but also because expressing the
relationship between distance and volume in this way obscured the
diminishing returns to higher levels of fuel economy. As a Wall
St. Journal column earlier this week put it, adding electricity
into the mpg mix, "risks giving consumers inaccurate information
about the financial and environmental costs of driving." But if we
need a new metric, what should it measure?/
>>>
>>> I think that the time is rapidly approaching for energy to be
measured in the only SI energy unit – joule – and that old
pre-metric measuring words for fuel efficiency should be converted
to the only SI unit available for energy efficiency for road
transport – joules per metre.
>>>
>>> As a starting reference, here are some examples:
>>>
>>> *Average car*
>>> 32 megajoules per litre (32 MJ/L) for lead free car fuel, and
>>> 10 litres per 100 kilometres (10 L/100 km) fuel consumption, then
>>> an average car consumes 3 200 joules of energy for each metre
it travels (3 200 J/m).
>>>
>>> *Average truck*
>>> 38.6 megajoules per litre (38.6 MJ/L) for diesel fuel, and
>>> 40 litres per 100 kilometres (40 L/100 km) fuel consumption, then
>>> an average truck consumes 15 440 joules of energy for each
metre it travels (15 440 J/m).
>>>
>>> *Average (school) bus*
>>> 38.6 megajoules per litre (38.6 MJ/L) for diesel fuel, and
>>> 35 litres per 100 kilometres (35 L/100 km) fuel consumption, then
>>> an average truck consumes 13 510 joules of energy for each
metre it travels (13 510 J/m).
>>>
>>> *Average Boeing 747*
>>> 34 megajoules per litre (34 MJ/L) for diesel fuel, and
>>> 16 litres per 100 kilometres (16 L/100 km) fuel consumption, then
>>> an average truck consumes 5 440 joules of energy for each
metre it travels (5 440 J/m).
>>>
>>> *Summary*
>>> Car 3 200 J/m
>>> Boeing 747 5 440 J/m
>>> School bus 13 510 J/m
>>> Truck 15 440 J/m
>>>
>>> As usual, I commend to you the simplicity of SI units and the
ease of understanding using whole numbers (see
http://www.metricationmatters.com/docs/WholeNumberRule.pdf ).
>>>
>>> Sadly, I could not find comparative figures for electric cars
– even at
http://www.optimalenergy.co.za/news/article.php?pk_news_id=112v
>>> Cheers,
>>> Pat Naughtin
>>> Author of the ebook, /Metrication Leaders Guide,/ that you can
obtain from
http://metricationmatters.com/MetricationLeadersGuideInfo.html PO
Box 305 Belmont 3216,
>>> Geelong, Australia
>>> Phone: 61 3 5241 2008
>>>
>>> Metric system consultant, writer, and speaker, Pat Naughtin,
has helped thousands of people and hundreds of companies upgrade
to the modern metric system smoothly, quickly, and so economically
that they now save thousands each year when buying, processing, or
selling for their businesses. Pat provides services and resources
for many different trades, crafts, and professions for commercial,
industrial and government metrication leaders in Asia, Europe, and
in the USA. Pat's clients include the Australian Government,
Google, NASA, NIST, and the metric associations of Canada, the UK,
and the USA. See http://www.metricationmatters.com
<http://www.metricationmatters.com/>
<http://www.metricationmatters.com/>for more metrication
information, contact Pat at [email protected]
<http://us.mc824.mail.yahoo.com/mc/[email protected]>
<mailto:[email protected]
<http://us.mc824.mail.yahoo.com/mc/[email protected]>>
or to get the free '/Metrication matters/' newsletter go to:
http://www.metricationmatters.com/newsletter to subscribe.
>>>
>>
>
