P plate training ...not

Hooked up to the injector drive, yeah, you could get a pretty accurate
_relative_ measure of fuel consumption, maybe +/- 1% if you really
worked at it. It's not quite the right tool for the job, but it's
close.

Hammo wanted to establish that bike regulators are no longer shunt
regulators like old Truimph "zeners".

Actually, I think I can establish that more easily with a half-decent
thermometer: if the regulator is switch-mode, its heatsink temperature
should go _UP_ slightly under headlight load, whereas if it's shunt,
its heatsink temperature should go _DOWN_ under headlight load.

Doing this experiment is left as an exercise to the reader.

------sharks

 

Nice spin, if you'd like to connect the quote in context with the
meaning, you'd extrapolate that as me saying "in a domestic situation
noone could be arsed doing that test"

Which is pretty much what I would say

JL
(to paraphrase someone in this thread - "you buy a 5.7L V8 you don't
give a shit about fuel consumption accuracy plus or minus a litre or
2)

 

<raised eyebrow> Who said you needed a fuel flow measurement to
improve fuel economy/efficiency ?

JL
(I've said repeatedly you can't make assumptions about a multitude of
things, calculate a fuel flow and then claim you know it's
particularly accurate though)

 

I still argue thimbles, though no body cares, I'd go for an order of
magnitude lower. I cannot differentiate between the fuel use with lights on
vs lights off. Air-conditioning is an all together different matter.

Hammo (I'll post my calcs when I get back home, probably after I post the
belated pics of roadside furniture to Theo).

 

Heh, you working for Slick50? That is the quality of their comparos too!

You see. You have spun yourself!

I'd say buy an X L V8 if you were inclined to towing loads where vehicle
mass and torque were concerns. Fuel consumption and it's measure would not
be a focus.

Hammo

 

Cold beers at the Wig and Penn..... Bye.

Hammo

 

You've really done it now, Sharkey, Now you'll have to be on my side!

Hammo

"We've got videos to talk about, haven't we, Mike?"

 

Thank you, Mr Echo. Your support is much appreciated.

Hammo

 

OUT!

15 - love to Hammo.

;-)

big (Yeah, I fell for one of his sucker lines upthread too...)

 

So because you can't differentiate the fuel use there is none?

A lounge suite in a layby?

Theo

 

On observation, that is currently true. However.......When I finish a PM
shift and drive the 3 and bit hours home in the dark (headlights on) the
fuel consumption has been equivalent if not better than during the day
(headlights off).

I change into top and then don't down change again until 3 kays from home
where I need to negotiate a sharp turn.

I've been looking to put a cruise control in so that human error can be
minimised wrt throttle input.

No, that discussion about lamps, sign posts and road markers. They are all
roadside furniture. I even went along to be involved with the taskforce
that investigated and reported via the inquiry into road deaths in rural
Victoria.

I took some pics as I couldn't get hold of the photohgraphs I wanted to show
you (i.e. Theo).

Hammo

 

Ahh I always knew you were a politician not a scientist - Howard
really should employ you, I've never know such capability to ignore
intent and pretend to hear something different to what was said.

So I ask again WHO SAID you needed a fuel flow measurement to
improve fuel economy/efficiency ?

Knock that straw man down you set up Hammo.

JL

 

I'll be interested to see them. I'm still reasonably sure about my
numbers, with the proviso that I'm basing them on a bunch of
unsupported wikipedia values...

The forst wikipedis value is for the energy content of petrol at ~32MJ/L:

http://en.wikipedia.org/wiki/Gasoline#Energy_content

Joules are easily expressed in Watt hours, so Watt hours can be
expressed in L of petrol.

1 Watt Second = 1 joule

1 Watt Hour = 3600 Watt Seconds = 3600 joules.

120 Watt hours = 432,000 joules (120*3600)

So if everything was 100% efficient that'd be .0135L (432,000/32,000,000)

But wikipedia says alternators have an efficiency "between 50 and 62%"
http://en.wikipedia.org/wiki/Alternator#Automotive_alternators

So lets use 55% and increase our fuel requirements by 1/0.55 to 0.0245L.

Now we make one more trip to wikipedia to find out how efficient the
internal combustion engine is, and they tell us "It is generally
accepted that most gasoline fueled internal combustion engines, even
when aided with turbochargers and stock efficiency aids, have a
mechanical efficiency of about 20%."
http://en.wikipedia.org/wiki/Internal_combustion#Engine_Efficiency

So we need to multiply our fuel requirements by another factor of 5 to
get 0.12L of fuel used for each hour of generating 120W of electrical
power using an automotive alternator driven by an internal combustion
engine. I'm guessing my errors are around +-40% (20% in the alternator
efficiency figure and another 20 in engine efficiency one).

Lets do a sanity check on that. Honda make little generators which are
actually dc alternators with inverters (click the "Inverter" link in the
left column of the webpage below for details). The 1000W model,
http://www.hondapowerequipment.com/ModelDetail.asp?ModelName=eu1000i has
got a 0.6gal/2.27L tank and they claim that it'll run for 3.8 hours @
rated load and 8.3 hours at 1/4 load" so they're saying 0.6L per hour
for 1000W or 0.27L/hour for 250 Watts - that last figure looks pretty
damed close to my calculation of 0.12L/hour for 120W... (the full load
figure is clearly running somewhat more efficiently though, but still
within my stated error range)

I reckon you must have pretty big thimbles...



big

 

You've also accounted for different air temperatures and densities (both
in terms of the engine combustion process and the aerodynamic effect)?

You've averaged the observations over trips from home in the dark and
light as well as to home in the dark and light (to remove any elevation
changes)? If you've done this then presumably you've checked the tire
pressures and wheel alignment regularly during the test procedure? And
kept the air-con off so differing compressor cycle times due to
different outside air temperatures wouldn't affect the results? Is there
a typical prevailing wind speed and direction in the area of the trip,
and is it the same for both day and night trips?

My numbers suggest you're looking for something like a half or one
percent increase in fuel consumption at highway speeds in a car that
averages around 15L/100km. I think _lots_ of other things will have
effects that overshadow it, but I honestly believe if you _were_ careful
enough in your measurements you'd see a real-world cost of ~0.35L over
your 3-ish hour trip if you do it with headlights on. My experience is
that I never get repeatability to anything better than about 10 or 20%
in my fuel useage even when I think I'm doing exactly the same trips, so
I'd only expect it to show up "in observation" through application of
some effective statistical methods over many many trips...

big

 

Rooobish !! I'm appealing to a higher court.

Theo - there's nothing higher than an ivory tower, what say you ?!

JL

 

Maaaaateeee ! Have I got a deal for you - buy a case and I'll throw in
a set of steak knives !

Around around the mulberry bush, like a tickly bear(1)....

XLV 8, hey, is that the new Honda replacement for the transalp ?
800cc's ?

JL
(1) Bloody hell I'm turning into a parent, scary.

 

er... John... you *do* realise you've let yourself get sucked into one
of Hammo's 'arguments', don't you?

Moike

 

How do you know ?

Nev..
'04 CBR1100XX

 

"Every"? I never learned that in Yr 8 Science. I think you need a more
accurate device for measuring Year 8 Science students.

Nev..
'04 CBR1100XX

 

No no no. Having an accurate measurement device for buses does not
automatically make any other measurements automatically flawed. You
have once again made an unsubstantiated allegation and pretended that
it's true. You have yet to establish that the car measuring device is
less sensitive or accurate, other than by merely saying that it is.

Nev..
'04 CBR1100XX