Fuel Misers

[Jody]

People by diseasels for the economy, and then cane them everywhere, utterly destroying any small advantage of owning one. Why?

and then map the daylights out of them, delete the DPF/cats and turn them into rolling coal. To the point where the youth think that a thick cloud of soot from a tuned diesel is a good thing.

 

[Dirk]

Right, just given the Pension Book Special a clean.

I got a hossy appointment at half nine tomorrow, so I've plugged in the pre heater and set the time. Should use less fuel when pre warmed, and the immediate presence of warm air when the engine starts will be a billy bonus.

Ah....but will the amount of energy expended to pre heat the engine be less than the amount of energy that would be lost by driving straight off on a cold engine?
Laws of Physics an' all that.

 

[Drago]

Supposedly, yes, at least in terms of price. That'll be part of my experiment to confirm.

If I had one of those Tesla solar batteries I'd be laughing.

 

[DaveReading]

So dropping the speed on an uphill saves more fuel than dropping the speed on the flat (in this particular example, more than twice as much).

But you could equally argue, from your figures, that the more you drop your speed (by 15 mph on the flat, by 20 mph going uphill), the more fuel you save. I think we probably knew that.

 

[lazybloke]

Ah....but will the amount of energy expended to pre heat the engine be less than the amount of energy that would be lost by driving straight off on a cold engine?
Laws of Physics an' all that.

Round here on frosty mornings, a lot of people defrost their car by leaving the engines idling for 10 minutes in the drive (unattended).
I imagine the thermal efficiency of a pre-heater is MUCH higher than the thermal efficiency of an idling internal combustion engine, so bring on the pre-heaters.

Sorry @Dirk, that doesn't quite answer your question.

 

[mjr]

But you could equally argue, from your figures, that the more you drop your speed (by 15 mph on the flat, by 20 mph going uphill), the more fuel you save. I think we probably knew that.

Well yes, but isn't that obvious? Whereas being more advantageous dropping speed uphill is contrary to what some people were implying earlier. It's what I'd expect from cycling because I get less tired if I don't max out up hills even if it takes longer, but it's nice of @swansonj to run the tests in a car.

I'm still intending to compare my car coasting in gear with neutral as suggested upthread but it may be almost another week before I drive again

 

[gbb]

and then map the daylights out of them, delete the DPF/cats and turn them into rolling coal. To the point where the youth think that a thick cloud of soot from a tuned diesel is a good thing.

Rolling coal.... best one I heard today.

 

[Dirk]

Round here on frosty mornings, a lot of people defrost their car by leaving the engines idling for 10 minutes in the drive (unattended).
I imagine the thermal efficiency of a pre-heater is MUCH higher than the thermal efficiency of an idling internal combustion engine, so bring on the pre-heaters.

Sorry @Dirk, that doesn't quite answer your question.

Driving off gently from cold is the quickest way to warm an engine up. Whilst the engine is getting up to temperature it is not sitting stationary ie. you are putting miles under your wheels. It may not be the most comfortable way to warm an engine up on a cold morning, but it negates the energy requirements of a pre heater. You don't get something for nothing in the energy stakes.

 

[DaveReading]

Well yes, but isn't that obvious? Whereas being more advantageous dropping speed uphill is contrary to what some people were implying earlier.

But the experiment hasn't attempted to separate the effects of the two variables which were introduced simultaneously. In one case, the car slowed down a bit and was on the flat. In the other case, the car slowed down by more and was on a hill.

How can we tell what the respective contributions of each of those two variables were?

 

[mjr]

But the experiment hasn't attempted to separate the effects of the two variables which were introduced simultaneously. In one case, the car slowed down a bit and was on the flat. In the other case, the car slowed down by more and was on a hill.

How can we tell what the respective contributions of each of those two variables were?

Sure, it wasn't a perfect experiment, so we can't tell how much was from each factor, but it suggests there's a hill effect because it seems unlikely that 5mph extra would double the saving.

 

[Ming the Merciless]

Used exactly zero gallons on the bike today

 

[Dirk]

Used exactly zero gallons on the bike today

Me too. Walked into the village and back to get shopping, then walked back in again for lunch. Walked my doggie on the fields across from me.
Haven't used my car for 4 days.

 

[Ming the Merciless]

Me too. Walked into the village and back to get shopping, then walked back in again for lunch. Walked my doggie on the fields across from me.
Haven't used my car for 4 days.

Haven't used mine since Saturday.

 

[mjr]

Me too. Walked into the village and back to get shopping, then walked back in again for lunch. Walked my doggie on the fields across from me.
Haven't used my car for 4 days.

Me three. Did the main weekly shop: big double panniers, saddle bag and handlebar basket. Think I last drove last week some time.

 

[Mr Celine]

The other thing missing from the experiment is the fuel consumption while accelerating back up to 60 mph.

But given the inaccuracies in trip computers over the 600 miles between fill ups the data from a single mile is probably worthless.