Fuel prices

[andrewsmith]

Originally Posted by -Ralph-

Sounds like a central heating oil tank in your garden somewhere may be a worthwhile investment, but you'd need some kind of insulation or heating around it.

Can any diesel vehicle run on this stuff, ie: modern common rail turbo, or it it just older more agricultural engines?

Everyone I know that runs cooking oil has got old landies or engines Pre the Euro 3 Regs, or bus/ truck derived designs (think Perkins, not pentium)
Not common rails or any of the modern engine designs

Originally Posted by bluefishman

rtfm,

Alright 20 litres then smart ass

don't get svo confused with bio-thats the common mistake

Originally Posted by EssexDave

Hong, I'm not happy about it other than the fact I'm now driving a diesel doing about 55-60mpg rather than my 25-30mpg astra.

It also makes the game of 'how many miles to a full tank' more interesting, although last month, I lost by about 150 miles....agressive with the right foot a little?

I knew you weren't happy about it either, it was just that smiley on the end I was kidding about

My 118D did 430-480 per tank in the summer, last few months I'm getting 380-400. I hope its only the cold that's doing this! If anything in the ice/snow I spent a good week driving like a grandad.

Diesel fuel needs heat to ignite; the intake temperatures dropping too low will reduce the economy.

Common tricks are to block the front of the intercooler with a sheet of card and to move the air intake from the front grill to near the exhaust manifold; ducting is available in a verity of sizes from most motor factors.

I knew it would make a difference, but just didnt know it would be this much. I thought modern engines didnt suffer too much from this type of stuff.

[embee]

Depends a bit what length journeys you're doing. A lot of fuel energy goes simply into heating up something like 3-400kg of engine+transmisssion+coolant circuit from a cold start. The shorter the trip the bigger the hit from warming it all up. When it cools again all that fuel energy is lost.

As for the ambient temperature effect, assume the normal running temp is around the 90C mark, if you start from minus 10C you're heating it through 100degC, if you start at 25C it's only 65degC.

A very simplified sum, 150kg of alum + 150kg steel (typical family saloon) heated 100degC takes 100*((150*0.9)+(150*0.5))kJ = 21MJ of heat energy . Typical fuel is around 43MJ/kg so half a kg (0.7 Litre) of fuel is required to supply the heat.

If you do a 10mile trip which uses, say, 1.0 Litre of fuel for motion+normal heat loss, plus 0.7 L for warm-up from minus 10C cold start, that's 5.9 mile/L (26.7mpg).
From plus 25C it's 1.0 L for motion+normal heat loss and 0.45 L for warm-up so 6.9 mile/L (31.2mpg).

It's a bit simplistic, but that gives an idea of the effects anyway.

That's not including the greater friction (oil) effects at low temps and a bit more heat loss to ambient too, so fuel for motion will increase and make the effect even worse.

Originally Posted by embee

Yeh-what he said man

It sounded impressive. All I know is, we're being ripped off by this government.

[Biker Biggles]

Originally Posted by Ed

It sounded impressive. All I know is, we're being ripped off by this government.

Its that bl00dy Gordon Brown.
I told you we should get rid of him.