Fuel Consumption from Dyno Test

Submitted: Monday, Jan 30, 2006 at 16:07
ThreadID: 30248 Views:1970 Replies:7 FollowUps:1
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Afternoon all,

Just a quick one. Is there a way to measure fuel consumption by just using a dyno?

The reason I ask is from post 30198 - Bill S rekons he has shown in 2 dyno tests (taken 47 minutes apart) that his Feltch has caused a lower fuel consumption in the second test.

Now, I thought power and torgue was measured in a dyno. Somehow he has come up with fuel figures of 20.4L/100km then 19.1L/100km.

Can someone explain how this would be possible?

Cheers,

Chump
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Reply By: Member - Paul P (Bris) - Monday, Jan 30, 2006 at 16:37

Monday, Jan 30, 2006 at 16:37
G,day

The use of fuel flow meters (usually) allow the calculation of fuel consumption when using a dyno. Variations in fuel consumption can be due to many factors when using a dyno.

Regards

Paul
AnswerID: 151830

Reply By: bombsquad - Monday, Jan 30, 2006 at 16:38

Monday, Jan 30, 2006 at 16:38
not really sure how the litres per km could be measured, but a simple test would be a fuel flow metre and measure the ratio of fuel to kW hours
AnswerID: 151832

Reply By: Member - Hugh (WA) - Monday, Jan 30, 2006 at 16:40

Monday, Jan 30, 2006 at 16:40
Hi Chump Boy,

Calculating fuel economy is typical calculation for a chassis dynamometer. Ratio of roller size and rotational speed gives distance and a gravimetric fuel flow meter (additional test equipment) will give fuel flow. Combining the two provides for calculation of fuel economy.

Regards,
Hugh
AnswerID: 151835

Reply By: Member - ROTORD - Monday, Jan 30, 2006 at 17:40

Monday, Jan 30, 2006 at 17:40
Hello chump_boy

The fuel consumption calculated would be highly accurate in relative terms but not in absolute terms . That is , between the two runs , percentage consumption gained or lost would be accurate , but road consumption accuracy would depend on the drag configuration of the vehicle .
AnswerID: 151854

Reply By: Ken - Monday, Jan 30, 2006 at 21:33

Monday, Jan 30, 2006 at 21:33
Hi Chump Boy,

As others say the fuel economy can be measured easily by the use of a fuel flow meter, strickly not part of the dyno but often used in conjunction with one.
What is probably not realised , specially if you are looking for particular result, is that there are many variables in such an exercise as this and eliminating them is vital to getting accurate and meaningful results. eg. was the dyno load applied exactly the same in each case ?
In my view the difference is small and most likely within the limits of variability [and possibly also accuracy] of the test method and equipment.

Ken
AnswerID: 151928

Reply By: arthurking83 - Monday, Jan 30, 2006 at 23:59

Monday, Jan 30, 2006 at 23:59
He may have been using the figures from a "trip computer", as most vehicles tend to come equipped with these nowadays???

Dunno??

But!!!
I'm weary of wild claims, even if I saw it with my own eyes!

If he want's to prove that this fletch fuel filter really works, he could hand them out(with a bond, of course) and not charge the customer, until that customer has realised a fuel saving!!

The customer would therefore only "lose" the amount of money it cost to install(and subsequent removal) of the flitch! ;)
AnswerID: 151989

Reply By: chump_boy - Tuesday, Jan 31, 2006 at 08:13

Tuesday, Jan 31, 2006 at 08:13
Thanks everyone for your responses.

I now know a bit more about dynos!...lol

Cheers,

Chump
AnswerID: 152006

Follow Up By: fnqcairns - Tuesday, Jan 31, 2006 at 13:09

Tuesday, Jan 31, 2006 at 13:09
Also there would need to be a corresponding rise in HP to accompany the better economy. They go hand in hand - until that is a person starts using the extra power. he he.

cheers fnq
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FollowupID: 405623

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