From: Stephen Bagwell on
On 18 May, 09:00, Adrian <toomany2...(a)> wrote:
> Stephen Bagwell <stephenb196...(a)> gurgled happily, sounding much
> like they were saying:
> > How many less tonnes of carbon dioxide have been produced because of
> > Americans driving hybrid Toyota and Lexus cars?
> Compared to what?
> (Total non-sequitur ignored for the moment)

Compared to a Cadillac Escalade
From: Adrian on
"GT" <a(a)b.c> gurgled happily, sounding much like they were saying:

>>> mpg is a measure of efficiency - it indicate how much fuel the vehicle
>>> needs to move a certain distance. The vehicle that uses less fuel for
>>> the same distance is more efficient.

>> If I had a lightweight motorbike which did 50mpg and a 3.5t van which
>> did 40mpg laden, which would you say was more efficient?

> We were comparing petrol cars versus diesel cars. Comparing motorbikes
> with vans is just as silly as it is irrelevant to the original *car* mpg
> discussion.

>> If I came up with a technology that allowed me to dilute petrol 50%,
>> making 2 gallons of fuel from one of neat petrol - and applied it to a
>> car that normally did 40mpg on neat fuel, but now does 30mpg on dilute
>> fuel, which would you say was more efficient?

> Neither - we were talking about the efficiency of 1 car versus another.
> If you were to devise such a system, then it could (presumably) be
> applied to all cars, therefore making the same *efficiency* saving
> across the board.
> You haven't tho have you? Can I be your friend if you do?

I think those goalposts just broke the land-speed record, so between us
we can rule the world...
From: Adrian on
BrianW <brianwhitehead(a)> gurgled happily, sounding much like
they were saying:

>> How about we do a real-life comparison test? Would that satisfy you?
>> I'll drive a car into a solid wall, whilst Duhg rides a bike into a
>> similar building.
>> 'course, for a fair test, it'd have to be from the same speed - as high
>> as possible, ideally. Duhg - what speed can you manage on your bike? We
>> can find a really steep hill if it's a help.
>> Hell, I'll even source a car, if somebody promises to video the result
>> and put it on YouTube.

> That would be a completely pointless experiment, as the results are
> entirely predictable.

I know. But it'd still be worth doing.

> Gollum's thick skull would cause more damage to the wall than any car
> could.

There's only one way to be sure.
From: boltar2003 on
On 20 May 2010 16:33:35 GMT
Adrian <toomany2cvs(a)> wrote:
>boltar2003(a) gurgled happily, sounding much like they were
>>>>>Bloater seems to think this is somehow relevant to lean burn petrols.
>>>> Because a lean burn engine basically gets rid of throttling losses so
>>>> is more efficient at lower rpm when the throttle would otherwise be
>>>> partially closed.
>>>ITYM "diesel". Lean-burn petrol is still throttled in the usual way -
>> No they're not. Thats the whole point you numpty.
>So - do tell us - how DOES it work?

It reduces throttling loses by regulating engine speed by regulating the
amount of fuel on a more or less constant throttle. Thats where the very high
air to fuel ratios from. Did you think the combustion in the chamber was
somehow magically different to a normal petrol engine that meant it could
generate the same power from less fuel? You get max power you when the fuel
is completely burnt and that already happens in a standard petrol engine


From: GT on
"Nick Finnigan" <nix(a)> wrote in message
> GT wrote:
>> "Nick Finnigan" <nix(a)> wrote in message
>> news:ht3r1e$p0f$1(a)
>>> GT wrote:
>>>> Comparing CO2 output from 2 different hydrocarbons doesn't compare
>>>> efficiencies, it simply indicates how much carbon there was in the CH
>>>> compound. That is a measure of emmisions and a clever way of taxing the
>>>> motor vehicle. To compare efficiency between 2 hydrocarbon burning
>>>> devices, we have to examine how much hydrocarbon source is used to
>>>> generate a fixed amount of power.
>>> 'how much' is measured by mass, or energy.
>>> MPG is such a measurement.
>>> No, it isn't.
>> We were trying to measure efficiency, not count 'how much' emmissions are
>> produced. mpg is a measure of efficiency
> No, it isn't.

OK, lets make it simple for the people that clearly didn't study and maths.
Given 1 gallon of fuel, a car that can propel itself for 50 miles is more
efficient than a car that can propel itself only 40 miles. Simple as that.
The car with the higher MPG, burns fuel more efficiently. That clear?