In article
,
Tim+ wrote:
This bit about diesels being so efficient that they are slow to heat up a
car has got to be nonsense.

Think about it. ICEs turn fuel into heat and heat into motion. An
efficient engine turns more of that fuel into motion by generating more
heat from the same volume of fuel.

Therefore a 100 bhp petrol engine or a 100 bhp diesel are both producing a
100bhp‘s worth of heat, it‘s just that the diesel is burning less fuel to
produce that heat.

At full output, the difference in efficiency between petrol and diesel
isn't so great.

It's at low output where the two diverge more. Hence things like local
delivery vans being diesel for a very long time.

And poorer efficiency means more waste heat. And warming up very rarely
happens at full engine output. If it did, most won't last that long.

Of course modern engine management has brought the two closer than once.
But hasn't done much about a petrol engines being at its most inefficient
when warming up.

--
*You never really learn to swear until you learn to drive *

Dave Plowman London SW
To e-mail, change noise into sound.