Ford diesel mileage

[em14]

I understand that some states are going to install "power" outlets at the rest stops for truckers to use for the power to operate heat and cooling etc. on their rigs and not allow long idle periods for diesels. I was not able to find that info but here is some articles about idleing diesels ...
http://www.epa.gov/Region1/eco/diesel/assets/pdfs/Diesel_Factsheet_Truck_Idling.pdf
Frequent Questions - Idling Reduction - SmartWay Transport Partnership - EPA

Leo

 

[patrick_g]

Curt, Sounds like we have about the same truck. Mine is 4x4 though. Just driving with no load (70 on interstate, 65 on regular highway, and speed limit most of the time in town when able and I have seen the cumulative mileage work its way up to register 16 on the highway but gets knocked down a bit (about 14.5) in city or short trips. Haven't run it continuously more than an hour and a half yet so don't know what I would get on an extended x-country trip.

I like the factory instruments (better than my Dodge-Cumins) but wish they included a pyro. I like to know what is going on and will probably add one like I did to the Dodge.

Pat

 

[jcmseven]

Patrick,

With my truck, I noticed the mileage being lowish until I reached about 3000 miles and then it has gotten a good bit better. Partly due to my taking longer trips and partly due to break in, I think this is about where the numbers start to increase. I noticed the shipping weight of my truck to be 7213 pounds on the spec sheet, so to me the mileage I am getting with it given it is heavy, square and has big parachute towing mirrors is pretty good. This weekend my wife and I went to my parents for their 50th anniversary/party. Usually I would tow with my truck but we took the Acura MDX we also own this time. I pulled my smaller trailer 6x12 with my new Gator on it which is a total load of about 2500 pounds. The Acura gets about 22 on the highway without a trailer, but it got only 13 pulling a really negligible load this weekend. Given that the Acura is considered very fuel-efficient for an SUV, it shows just how well ALL these diesel trucks really do. I feel pretty confident I could pull my 8000# total weight trailer with tractor and get about the same as I did this weekend pulling a much smaller load with our MDX and my truck I think is not fully broken in yet. Pretty impressive to me. I think my original reason for posting seems to be the case: the emissions upgrades seen for the new model diesels are not negatively affecting fuel economy as I, and some others, expected. Thank you all for the posts thus far.

John M

 

[machmeter62]

The milage of a vehicle that is running but not moving is negative. If you fill up, drive 20 miles using 1 gal you got 20 miles per gallon. If you keep the engine running at idle for an hour and use 1 gal, you used 2 gal to go 20 miles or 10 mpg.

Diesels may use less fuel at idle than equally sized gas engines, but not that much less. In the winter, starting and idling the engine uses as much fuel per minute as driving on the highway at 65 mph. At least it did with mine when I checked it.


I have no idea why big rigs sit and idle other than to power the heat, AC, refridgerator or radio/TV/computer. You would think that they would run separate banks of batteries for starting and accessories with automatic combiners to charge as needed - like a large boat does. But I'm just guessing here and don't really know.

jb

JOHN: CUMMINS CUSTOMER ASSISTANCE states, "at idle the diesel engine fuel to air/ratio is 85/1 to 100/1; under load it is a miserly 25/1 to 30/1." I think a gas engine needs a constant ratio of 15/1 for all parameters? I think that translates to 6X less fuel at idle versus gas engines??

 

[firemanpat2910]

2003 duramax 2500 allison with 60346 miles recorded - 18,975 towing ~9k;

17.64 mpg lifetime average since new.
Max 22.37
Min 10.92
172 fillups total
47 fillup's over 19 mpg
17 fillups under 15 mpg
39.9 vehicle average MPH

61,xxx miles now

jb

You sir have entirely too much time on your hands. I couldnt even guess how many fill ups Ive had.

 

[UPRAISER]

Pat

I forgot to include that my 2008 is a 4x4. I put a canopy on it and was hoping to see a bit of improvement in the milage, so far nothing.

I was surprised and pleased that the milage average got over 16 on a short 50 mile sprint up the freeway. I was rolling along at 70- 80 mph trying to keep up with traffic.

I presume that on a longer trip the average will be a bit better since it is an average mpg.

I am planning a long trip for 6 weeks into Alaska in Mid August. I will give it a good work out.

I had a 99 F150 4x4 and really liked it, I had 165000 miles and it had only a couple problems, one was a leak between the tranny and transfer case at 80,000 miles, it showed up at 160,000 again. The other was the overdrive switch, I ran through 3 of them. The last, at $185.00 per unit found the problem was a small wire that rubbed the insulation off was causing the problem. The Ford dealer never told me, my independent shop owner did and a little tape, fixed it.

I hope that the F250 will be as good.

Curt

 

[patrick_g]

Curt, I did Alaska for 3 weeks a few years back and enjoyed it very much. Flew in and rented an older used RV out of Fairbanks from a guy with 3 units. Lots of miles of gravel roads but never a problem and with 4x4 you would have to look for trouble to find any. Off the beaten path, fuel can be expensive and not available every few miles so don't let the tank get as low as you would in "civilization."

Hope you have a great time. Thank you for the encouragement re mileage. I was happy to see the computer report 16 but more is better and will be very welcome.

Pat

 

[john_bud]

JOHN: CUMMINS CUSTOMER ASSISTANCE states, "at idle the diesel engine fuel to air/ratio is 85/1 to 100/1; under load it is a miserly 25/1 to 30/1." I think a gas engine needs a constant ratio of 15/1 for all parameters? I think that translates to 6X less fuel at idle versus gas engines??

No, not quite. Modern fuel injected engines go to a lean condition at no load idle and inject a lot of exhaust gas to reduce the high temperatures lean burn creates. In the 25:1 range. So, the diesel is 3-4x better at idle. But a 1.8l honda engine will use the same fuel at idle as it is 1/3 the displacement.

I'm not sure about the under load number of 25:1 or 30:1. It smells like a part throttle cruise number to me. A full load peddle down is 16 or 18:1. If you are able to see black smoke out the pipe, it's less than 14:1. Don't forget that when you get on that cummins it's putting out about 30 psig into the engine, which about triples the effective displacement of the engine. So, you are using fuel for 3x5.9 liters or about 18 liters of naturally aspirated engine. So the 18:1 AFR is throwing in a lot of fuel to get the big power.

{Maybe the 2007+ electronics are leaning it back to drop particulates? Hard to keep up with technology....}

Still and all, Diesel is more fuel efficient than gas engines. Displacement for displacement and HP for HP. That's why there is 1 truck engine and 3 tractor engine all diesel in the stable.



FiremanPat2910 - too much time? No, the excel spreadsheet does it in a flash and automatically calculates it up with no input on my part. (other than the first time I added the formulas). It's just my love of data and data mining for information.

jb

 

[Dargo]

I think a gas engine needs a constant ratio of 15/1 for all parameters?

That is also what I recall from class, but it's been quite a few years. So, I cheated and looked it up again. Here are the facts on a gas engine fuel to air ratio: A stoichiometric mixture is the working point that modern engine management systems employing fuel injection attempt to achieve in light load cruise situations. For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture - given perfect (ideal) "test" fuel (gasoline consisting of solely n-heptane and iso-octane). In reality, most fuels consist of a combination of heptane, octane, a handful of other alkanes, plus additives including detergents, and possibly oxygenators such as MTBE (Methyl tertiary-butyl ether) or ethanol/methanol. These compounds all alter the stoichiometric ratio, with most of the additives pushing the ratio downward (oxygenators bring extra oxygen to the combustion event in liquid form that is released at time of combustions; for MTBE-laden fuel, a stoichiometric ratio can be as low as 14.1:1). At no point is a gasoline engine ever anywhere close to a 25:1 ratio.

In comparison, engineers and techs say that diesel engines run at varying air/fuel ratios. At idle, with no load, it is not uncommon to have a diesel engine running at an air/fuel ratio of 60 or 100:1.

 

[radman1]

Dargo

What is a tuit? Me and my Webster's want to know what I am looking for.