Does idling waste fuel? - Engineering Explained
- Thread starter StevieC
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I did the math years ago with a 2.2L subaru and was highly questioned [ridiculed by some] by folks on this board. I was working on my degree while working full time while living in DC with 2-3 hours commute per day. My home, my job, and my school, were in different states! So, I lived in my car a lot, either sleeping or studying or writing papers. In the heat of the summer, or the dead of winter, I ran the engine. Actually, during this time I had both a 2.2L subaru and later a 3.3L minivan. IIRC, both consumed about the same 1.5Gal/hour, which I knew very well because if I had 2 hours to study then sleep, that's not an insignificant portion of a tank.
The math went something like this. Idle = 1.5G/hr
Yet at 70mph, at 27 mpg, that's 2.6G/hr.
You'd *think* there'd be a much larger consumption rate between idle and freeway cruise. It was sort of eye-opening. Idling is really not that efficient, or wasn't in those late-90s vehicles.
-m
The math went something like this. Idle = 1.5G/hr
Yet at 70mph, at 27 mpg, that's 2.6G/hr.
You'd *think* there'd be a much larger consumption rate between idle and freeway cruise. It was sort of eye-opening. Idling is really not that efficient, or wasn't in those late-90s vehicles.
-m
For a $2 or $3 dollar additional cost, I fill up at a place with no lines. Time is money. $2 or $3 is a rounding error at the end of the week for many of us.
My dad, a depression (1929) baby would will be rolling in his grave after this message gets to him.
My dad, a depression (1929) baby would will be rolling in his grave after this message gets to him.
Originally Posted by VeryNoisyPoet
I have a scan gauge so I have some data for different conditions with my car.
0.35 gph warm in neutral/park.
0.47 gph warm in gear.
0.65 gph warm in gear with aircon.
If I'm stopped at several lights on a trip, there's a significant fraction of a gallon burned just sitting. I don't turn off at normal red lights but at railroad crossings where I know I'll be there a while I'll shut down and save a bit. If brutally hot I'll put in neutral instead because every little bit helps.
At 0.65 gph and $3 a gallon gas, a one minute stop light in gear costs about 3 cents. A 5 minute wait costs about 16 cents.
I have a scan gauge so I have some data for different conditions with my car.
0.35 gph warm in neutral/park.
0.47 gph warm in gear.
0.65 gph warm in gear with aircon.
If I'm stopped at several lights on a trip, there's a significant fraction of a gallon burned just sitting. I don't turn off at normal red lights but at railroad crossings where I know I'll be there a while I'll shut down and save a bit. If brutally hot I'll put in neutral instead because every little bit helps.
At 0.65 gph and $3 a gallon gas, a one minute stop light in gear costs about 3 cents. A 5 minute wait costs about 16 cents.
Originally Posted by irv
I always get a kick out of those purchasing gas at Costco. Most go there because gas is usually 5 cents or more cheaper than most places but because of that, the line ups are usually huge so it can take 5-10 minutes sometime before one pulls up the pumps.
99% of the vehicles I see there are idling the whole time waiting to get filled up which is likely throwing any savings they are receiving buying this cheaper gas right out the window.
Remember Costco is top tier, lol.
I always get a kick out of those purchasing gas at Costco. Most go there because gas is usually 5 cents or more cheaper than most places but because of that, the line ups are usually huge so it can take 5-10 minutes sometime before one pulls up the pumps.
99% of the vehicles I see there are idling the whole time waiting to get filled up which is likely throwing any savings they are receiving buying this cheaper gas right out the window.
Remember Costco is top tier, lol.
Originally Posted by irv
I always get a kick out of those purchasing gas at Costco. Most go there because gas is usually 5 cents or more cheaper than most places but because of that, the line ups are usually huge so it can take 5-10 minutes sometime before one pulls up the pumps.
99% of the vehicles I see there are idling the whole time waiting to get filled up which is likely throwing any savings they are receiving buying this cheaper gas right out the window.
not to mention probably half of them drove 20 miles to get there and "save"
I always get a kick out of those purchasing gas at Costco. Most go there because gas is usually 5 cents or more cheaper than most places but because of that, the line ups are usually huge so it can take 5-10 minutes sometime before one pulls up the pumps.
99% of the vehicles I see there are idling the whole time waiting to get filled up which is likely throwing any savings they are receiving buying this cheaper gas right out the window.
not to mention probably half of them drove 20 miles to get there and "save"
Yes, idling certainly wastes fuel. Reducing gridlock might be a better solution than stop/start. Oh, and here, in winter, I am going to idle.
Just don't use the drive through. Park, walk, transact, walk, drive.
Better for your body and the environment.
Originally Posted by PimTac
Originally Posted by camryrolla
Good video. Please make a point to turn off the engine after you pull into the bank's drive-through.
Good advice especially in Louisiana where air conditioning is not necessary.
[ sarcasm ]
Better for your body and the environment.
Originally Posted by PimTac
Originally Posted by camryrolla
Good video. Please make a point to turn off the engine after you pull into the bank's drive-through.
Good advice especially in Louisiana where air conditioning is not necessary.
[ sarcasm ]
0 mpg sounds like a waste to me.
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