Never mind the price per litre - what's the calorific value of the stuff they sell ?

peterbaker

I am gettig heartily sick of oil companies and retailers taking us for mugs.

Why are they permitted to sell us fuel without disclosing its energy content?

peterbaker

Blimey, am I about to learn something ?

Is the RON the calorific value?? I would like to see something in joules or calories per kilo please coupled with the specific gravity so I can convert it to joules per litre ... does RON do the trick?

Edit: Oh thanks brazilianwax, am I to assume that as you have deleted it without a further word, that your reply which was until a few minutes ago listed at post #2 suggesting that RON labels on every pump somehow provided calorific value was a bit fanciful? Its ok to say you barked up the wrong tree - you are in safe company - 30 million UK motorists do the same thing all the time ... I just thought it might be a good idea if we all woke up

vaio

When I was in school it was about 150,000 btu/gal (or 35 MJ/litre for youngsters)

It doesn’t vary much (if at all) between grades

anewman

It's all about how well the stuff ignites?

Woby_Tide

I think peterbaker must have got a new prescription lately the number of 'rallies against the cause' he has started in sucha short space of time......;)

Andy_L

Seeing as how the British Standard they conform to (BS7070 for unleaded?) covers the composition I'd expect it to be covered by that, though possibly indirectly.

peterbaker

Woby_Tide wrote: »

I think peterbaker must have got a new prescription lately the number of 'rallies against the cause' he has started in sucha short space of time......;)

Sorry Woby ... I have just been having a mental clearout - can't do much with those ideas just spinning in my head - thought they were best aired / chewed over ahead of the Revolution

Andy L I don't think anyone has pinned down the oil companies on this ... EVER! British Standards were never much protection to a consumer on any commodity. Mains Gas has long been supplied by energy value, but why isn't liquid fuel? It's because the lack of any figure gives the oil companies such an useful way to manipulate both energy prices and underlying demand, I reckon. And now they are far too big and powerful for the government to dare tackle it.

anewman

Andy_L wrote: »

Seeing as how the British Standard they conform to (BS7070 for unleaded?) covers the composition I'd expect it to be covered by that, though possibly indirectly.

Obviously didn't when Tesco/Morissons added silicon and killed off Lambda sensors.

Woby_Tide

isn't their an argument though that regardless of how the fuel is sold(and if teh earlier post is true, which I'm inclined to believe, that the calorific value won't change much between companies) it's the actual user/machine that has more to do with it. The gas coming through my meter has a pretty standard calorific value, I have two different gas fires that use it at different rates for seemingly equal heat output(in simplistic terms). I can't see how the calorific value could differentiate more than a fraction between suppliers, and any cost saved by changing suppliers would probably be negated travelling between the two

peterbaker

Take this typical piece of bamboozlng about fuel consumption improvements from using BP Ultimate Diesel. http://www.bp.com/sectiongenericarticle.do?categoryId=4005616&contentId=7009018

It would make an excellent GCSE maths comprehension question if any of the numbers added up in any useful sense :rolleyes:

Are we to believe from it that BP Ultimate Diesel (which costs about 5% or 6% more than their ordinary diesel I think), actually gives a least 5% or 6% better fuel economy? That would be the sensible thing to assume if we paid a fair price for the energy value of different grades of fuel ...

But no, we aren't allowed to understand such sensible concepts - instead we are blinded by "average" results in an unspecified selection of tests, and by "maximum" results, neither of which appear to add up to the example extra 8 miles or 22 miles per tank stated, even after we have converted the inconvenient metric kilometres in their results to the miles in their "blurb".

They say typical consumption from a 55 litre tank is 7 litres per 100 km ... that's 786 km per tank by my 1971 Grade 1 Maths O'level. Now if that was improved by 1% it would make a difference of 7.86km per tank which most certainly AIN'T 8 miles. And 3% would make a difference of 23.58km which is about 14.7 miles. Where'd that 22 miles come from again??

In addition, the 1% and 3% numbers in the chart do not add up to any supposed 5% or 6% extra that we are tempted to expect because that's what we've spent to put the hyped "superior" fuel in our tanks in the first place ... d'oh!

Oh but wait !! Surely we are missing something? What about power and acceleration?? Ah yes! That'll convince the punters!! Tell 'em power and acceleration can be 8% better! Then they'll forget all about 1% or 3% improvements in economy. 8% is the kind of number the punters want to hear ... for a start it's bigger than the 5 or 6% we are surcharging for the "Ultimate" label ... doesn't matter about what 100% this 8% is a percentage of ... no-one understands it anyway :rolleyes: ... just tell 'em 8% and link it loosely to the usual petrolhead concepts like power and acceleration ... And so we buy it :rotfl:

Edit for Woby: As I understand it, Calorific Value quite simply means how much heat energy can we get out of a standard mass unit of the stuff by burning it completely? Difficult to measure without specialised laboratory equipment, which is why most of us haven't a clue about it. A standard mass unit of the stuff might be a kilogram. At normal sea level temperatures and pressures that might equate to a litre and a half of 'petrol' for example. So how much heat can we squeeze out of it? Depends what's in it, I reckon. Now then, what's in the petrol/diesel? We know that there's not much water in it or they'd quickly be rumbled. No it's got all sorts of other mystery ingredients like anti-knock whatever (not lead anymore but something which means the whole mix can be labeled with an octane or cetane number instead), plus antifoaming agent in diesel and in Tescos/Morrisons petrol sometimes :rolleyes:, and more recently we've got biologically produced alternative fuel additives (perhaps sunflower oil at BP judged from their logo?), and goodness knows what else according to what the retailer thinks works in his branded product. Then by UK Government statute we also have intriguing winter and summer variations and maybe even intermediate ones depending on what month of the year it is. What the hell is that about? We are not an Arctic country - we are globally warmed most months! Most intriguingly of all, in the winter some people write that whatever the refineries/retailers do with the mix, what they add or take away actually reduces the calorific value :eek: . You would be forgiven for thinking I am sure that increasing it might be a more useful thing to do when it is cold! So is it worse than I thought? Is here in fact statutory collusion by the Government with the oil companies to make us buy more litres of "fuel" in the winter months?

It all sounds to me a bit like the Breakfast Cereals business. Most of what's on the supermarket shelves in the UK is sugar not cereals, and Kelloggs Cornflakes in one country can be found to comprise significantly different ingredients e.g. sugar proportions to Kelloggs cornflakes elsewhere. Kelloggs still maintain that they are in the cereals business, however. I would say they are seriously in the sugar business and several others also! We all know recognise the C*ck on their packet design, but the Bull is less easy to discern .

Woby_Tide

not disputing any of the figures but aren't their tests that prove higher octane fuel/premium brands in some cases improve engine performance/parts longevity comapred to say supermarket brands? In most curcumstances it's probably undetectable to the average user is the problem

(also just to point out in the smoke and mirrors game, one of teh quoted figures is 'per tankful', the tests just specify the 'same amount of fuel' so no guarantee that a full tank was used hence the discrepancy)