Temperature affects fuel economy-how much?
#21
Re: Temperature affects fuel economy-how much?
Another fast fact: E10 or 10% ethanol reduces tailpipe emissions by 30%.
( so you need to get 30% worse, or about 20 MPG in a FEH for this choice to be worse than pure gas.)
It is NOT a 1:1 ratio!
-John
P.S. The battery power allowed to come out, and go into the battery is reduced in both hot and cold temperatures. Above 100'F you loose 1 amp ( or 330 watts, or half a horsepower ) for each degree. Below 65'F ( or 60'F, I forget now ) you loose 1 amp per degree.
This is both due to chemistry, and the battery software being "gentle" with the HV battery.
The allowed discharge rate of the traction battery, according to the PIDs I display, does not decrease amp for degree above 100F - but it does drop fairly rapidly when SOC drops below 40%. I have seen max discharge as low as 16A when the SOC was at 32.8%. In another couple of months I might see battery temps below 60F, so I'll be able to look at the low end.
My scaling may be wrong for the PIDs, I see Max Discharge at 67.5A and Max Charge at 47.5A under most conditions. The drop in MxD below 40% SOC is definitely steep.
#22
Re: Temperature affects fuel economy-how much?
Another fast fact: E10 or 10% ethanol reduces tailpipe emissions by 30%.
#23
Re: Temperature affects fuel economy-how much?
You are wrong about ethanol. You can drink ethanol. The formaldehyde is nomally zero or below detectible limits in ethanol. I don't know about methanol. But maybe that's one reason ethanol is a much better choice than methanol. And earlier I was saying 10% ethanol in gas reduces HARMFUL emissions by 30%. ( I think the Federal Government says 29% ) The extra oxygen helps the gasoline burn more cleanly. It is much more complex than people think. It's not just about getting raw energy from ethanol ( the input/out ratio is up to 3:5 these days, putting 3 btu into ethanol production yields 5 btu out ) Give me $300 today and I'll give you $500 tomorrow. Want that deal? BUT ALSO the fact that ethanol can help us use the petroleum we have more effectively. Not to mention using our farmlands more effectively.
Would you rather support a farmer? Or a war over oil?
Would you like the oil we have to last 60 years? or 100 years?
Petroleum is used for many things other than transportation fuel.
Putting technical aspects aside, you have to look at the ethical, and social values of making your own fuel within your own borders.
Would you rather support a farmer? Or a war over oil?
Would you like the oil we have to last 60 years? or 100 years?
Petroleum is used for many things other than transportation fuel.
Putting technical aspects aside, you have to look at the ethical, and social values of making your own fuel within your own borders.
Maybe on a GROSS polluter you could get a 30%, maybe. The formula I was given by a non bureaucrat at EPA was at best 10% reduction in co and hc on paper BUT and increase in fuel consumption of 15 To 20% so the net was at best neutral or worse. Then there is the MTBE and formaldehyde (that is produced by burning alcohol) problem. ICEs should be as efficient as possible and that means a high CO2 output, then there is less nasty hc and co. ICEs would get higher fuel mileage lowering CO2 in the balance. I have worked with racing engines that burned methanol, nitro methane and gas. Methanol/alcohol is a bad fuel choice for every day driving. I will gladly trade CO2 for formaldehyde. I can planrt some trees and grass to take care of the CO2. Omnia in ponderas.
Last edited by gpsman1; 09-20-2007 at 10:15 PM.
#24
Re: Temperature affects fuel economy-how much?
I hate to disagree with you, John, but I must. Up here, farmers are plowing under food crops in order to grow corn for ethanol. They've stopped letting fields go to pasture to grow corn. I'm not sure that this is a more effective use of farmland because we need food to eat. Corn also is a nutrient intense crop and while it does sequester carbon rather well, it depletes other nutrients in the soil, so you can only grow corn for three or four years before you have to switch to something else (typically soybeans) or let the field go fallow.
I will leave the politics out of my response, but I would like to remind everyone here that the United States gets most of its oil from Canada and the Gulf Coast region (including Central and South America). Very little, if any, Middle Eastern oil actually winds up in your gas tank.
If the United States would actually let a refinery be built and look within its borders for crude, we wouldn't have any problems with supply.
I will leave the politics out of my response, but I would like to remind everyone here that the United States gets most of its oil from Canada and the Gulf Coast region (including Central and South America). Very little, if any, Middle Eastern oil actually winds up in your gas tank.
If the United States would actually let a refinery be built and look within its borders for crude, we wouldn't have any problems with supply.
#25
Re: Temperature affects fuel economy-how much?
The extra oxygen helps the gasoline burn more cleanly. It is much more complex than people think.
#26
Re: Temperature affects fuel economy-how much?
I'm getting to the thread late, but Mary... did your mileage bounce back up after the cold snap? I'm guessing we had similar weather there for a while.
You'll find winter to be very frustrating for FE- I have a chart showing the relationship between TEMP and MPG on the "Share" section of this site. Just keep saying to yourself that even though your MPG has dipped into the high 20's you're still doing way better than the average SUV.
You'll find winter to be very frustrating for FE- I have a chart showing the relationship between TEMP and MPG on the "Share" section of this site. Just keep saying to yourself that even though your MPG has dipped into the high 20's you're still doing way better than the average SUV.
#27
Re: Temperature affects fuel economy-how much?
My mileage has popped back up; I've switched to a different brand of gasoline and it seems to have helped. Also, I had the truck in the shop and apparently the mechanics don't care about FE because it dropped about 4 MPG while it was in there. I'm slowly recovering from the experience.
#28
Re: Temperature affects fuel economy-how much?
apparently the mechanics don't care about FE because it dropped about 4 MPG while it was in there.
#29
Re: Temperature affects fuel economy-how much?
Also, don't discount the effects of wind.
How many of you get 43 MPG at 70 MPH on the interstate with 500 pounds of cargo? Well, I just did that!
My whole tank was Eastbound, and I had a tail-wind.
If I was traveling Westbound, I probably would have gotten 25 MPG and might have been tempted to blame the gas, as my "driving style" will not change in 1 day, but the wind sure can!
-John
How many of you get 43 MPG at 70 MPH on the interstate with 500 pounds of cargo? Well, I just did that!
My whole tank was Eastbound, and I had a tail-wind.
If I was traveling Westbound, I probably would have gotten 25 MPG and might have been tempted to blame the gas, as my "driving style" will not change in 1 day, but the wind sure can!
-John
#30
Re: Temperature affects fuel economy-how much?
Also, don't discount the effects of wind.
How many of you get 43 MPG at 70 miles per hour on the interstate with 500 pounds of cargo? Well, I just did that!
My whole tank was Eastbound, and I had a tail-wind.
If I was traveling Westbound, I probably would have gotten 25 MPG and might have been tempted to blame the gas, as my "driving style" will not change in 1 day, but the wind sure can!
-John
How many of you get 43 MPG at 70 miles per hour on the interstate with 500 pounds of cargo? Well, I just did that!
My whole tank was Eastbound, and I had a tail-wind.
If I was traveling Westbound, I probably would have gotten 25 MPG and might have been tempted to blame the gas, as my "driving style" will not change in 1 day, but the wind sure can!
-John
Also, I said it in another thread. Temperature's effect on FE is more like a bell curve. It does improve with rising temps, but also drops off if temperature keeps rising. Now that the temps here have cooled off to the 90's, my FE went back up another 2-4 mpg.