Diesel Fuel Measurement ECM Trip Report

[jackalfa]

Diesel Fuel Measurement ECM Trip Report

I hope someone can help me with this issue:

How can I find out how actually the ECM calculates the fuel flow or fuel volume burned by an engine?

Which parts or sensors (flow meter?) are involved into the measurement of the data in the trip reports (Detroit Diesel, Cummins or Cat ECM's)?

My understanding is that the fuel system has a feed line and a return line to the tank or tanks, so how the ECM calculates which amount of diesel is burned by the in engine taking in account the returned fuel?


Thanks in advance members...

[oldford]

By knowing how big the injectors are and how much fuel is injected each and every injection. Then it's a matter of adding the amounts.

[Far_Call]

it is done in the ECM using the fuel tables and a know output of the injector. However if the incorrect trims are used the the ECM fuel Table Formula will be incorrect and as such display the incorrect fuel burn.
This can be adjusted in the ECM configuration on Road Trucks but not on Earthmoving.

[jackalfa]

Thanks a lot for your responses.
So if for example in Detroit Diesel there is a code that someone passed the tip hero to change the injector to 50 or 75 (can't remember now) it will compute very different fuel burn in the ECM and most likely incorrect?

[ddmech]

Not to my knowledge.I have put in hundreds of 75 codes and never affected the mpg in ecm versus mileage and actual fuel use.They will however help power and fuel mileage.(Regardless what ddc and some others say,LOL!)

[jackalfa]

Thanks for your comment ddmech.

[jctech]

If the ECM is knows the size of the injector, even if the trim files are changed, the ECM knows how much fuel is injected, even if the fuel flow is "incorrect".
If the injector is replaced by a smaller or larger injector, the ECM no longer knows the fuel flow. It thinks the flow is still the same as the original injector, and the ECM reported MPG will not be accurate.

[tonyspamone]

Hi Jack, its been awhile, the ecm bases it on the flash file for the given horsepower and torque map. all Cat fuel data is in gallons per hour. the ecm calculates load factor based on a number of items. the ecm uses this load factor to figure out miles per gallon. it knows how much fuel it takes to make a given amount of horsepower at different rpms and loads.


Diesel Fuel Measurement ECM Trip Report

I hope someone can help me with this issue:

How can I find out how actually the ECM calculates the fuel flow or fuel volume burned by an engine?

Which parts or sensors (flow meter?) are involved into the measurement of the data in the trip reports (Detroit Diesel, Cummins or Cat ECM's)?

My understanding is that the fuel system has a feed line and a return line to the tank or tanks, so how the ECM calculates which amount of diesel is burned by the in engine taking in account the returned fuel?


Thanks in advance members...

[jackalfa]

Hi Tony, thanks for your response and help, I appreciated. Happy to tell you hi and know from you. Best regards.

[jackalfa]

If the ECM is knows the size of the injector, even if the trim files are changed, the ECM knows how much fuel is injected, even if the fuel flow is "incorrect".
If the injector is replaced by a smaller or larger injector, the ECM no longer knows the fuel flow. It thinks the flow is still the same as the original injector, and the ECM reported MPG will not be accurate.

jctech thanks for your response, so when a injector is changed, the ECM needs to know the kind or size of injector installed by the trim files and/or the calibration number in the ECM injector parameter to know the fuel flow and report with accuracy the burned or consumed fuel?

regards...

[jctech]

jctech thanks for your response, so when a injector is changed, the ECM needs to know the kind or size of injector installed by the trim files and/or the calibration number in the ECM injector parameter to know the fuel flow and report with accuracy the burned or consumed fuel?

regards...

If the injector is replaced with the original part number injector (or a direct supercession) then only the trim files need to be updated if required. Cummins does not use trim files, just change the injector and you are good to go.
If the injector is replaced with a larger or smaller injector then the fuel used will be in error by the percentage difference in the injector cup capacity.
For example - the original injector has a cup capacity of 100cc per 100 strokes, the ECM knows that at full power each injector will inject 100cc fuel every 200 RPM, it also calculates for percentage of full power as well.
If the injectors are replaced with a larger part that has a cup capacity of 120cc per 100 RPM, the ECM thinks the engine is geting 100cc when it is really using 120cc and the reported fuel economy will be in error by 20%.

The most common cause of reported fuel economy being different to actual fuel used is theft, next most common is actual mileage recorded in the ECM being different to speedo mileage. I would doubt that theft is your issue as you have it across a fleet of trucks.

[jackalfa]

Thanks jctech, it really help me a lot all the info you are telling me. Your example about cup capacity of the injector is very clear, just some last doubts: in Detroit Diesel injectors, the info needs to be programed in ECM with DDDL with just the calibration number or with trim files programed in DDDL or DDRS, or with the data of cup capacity from the injector programed in the ECM calibration? How do I corroborate that the ECM programed injector is correct?
And what really happens if I change the injector calibration numbers in DDDL to all injectors to 75?

Thanks a lot jctech and sorry to keep bugging you.

best regards...

[jackalfa]

jctech, thanks again for your help, please if you you know the proper procedure to do in DDDL (DDEC V) after an injector change or recalibration please let me know. regards.

[jctech]

jctech, thanks again for your help, please if you you know the proper procedure to do in DDDL (DDEC V) after an injector change or recalibration please let me know. regards.

I do not use DDDL and do not know the procedure, only what people have told me about the trim codes.

I will leave this question for someone who knows the correct procedure for what you are asking.

[Thecell]

Jackalfa,

1. Use DDDL and go to the Diagnostics drop down.
2. Go to the Injector response times.
3. Set the injectors to the calibration number that is stamped on each of the injectors (if you want an accurate start)
4. There are several other factors that can affect the calibration of fuel milage (real milage) not what the computer displays.

What is you end goal...?
Then I can direct you to DDCT which will allow ALL changes to be made.

Hope it helps m8.

[jackalfa]

Thanks a lot Thecell,

The goal is to have the closest match in the trip report of the ECM to the pumped fuel in the tanks. I'm trying to calibrate the ECM to obtain the closest accuracy in fuel consumption: Actual Fuel Consumed vs. Electronic Fuel Consumed.
The tanks of the trucsk are filled up full and when they return, I'm checking the consumed fuel at the ECM, but when compared to the fuel refill at the pump I always get from 5 to 15 gallons difference. I'm checking the tanks levels at the moment to fill up the tanks to be the same, is the in site pump at the yard, same time at the moment to fill up, etc.
I would appreciate all the help you can give so I can obtain the closest match on both things or at least know the percentage of difference between Actual Fuel Consumed vs. Electronic Fuel Consumed in the DDEC V.

Thanks again, regards.

[Thecell]

Thanks a lot Thecell,

The goal is to have the closest match in the trip report of the ECM to the pumped fuel in the tanks. I'm trying to calibrate the ECM to obtain the closest accuracy in fuel consumption: Actual Fuel Consumed vs. Electronic Fuel Consumed.
The tanks of the trucsk are filled up full and when they return, I'm checking the consumed fuel at the ECM, but when compared to the fuel refill at the pump I always get from 5 to 15 gallons difference. I'm checking the tanks levels at the moment to fill up the tanks to be the same, is the in site pump at the yard, same time at the moment to fill up, etc.
I would appreciate all the help you can give so I can obtain the closest match on both things or at least know the percentage of difference between Actual Fuel Consumed vs. Electronic Fuel Consumed in the DDEC V.

Thanks again, regards.

Lets start with the tire rotation calibration. If your tire size in the ECM is wrong it will throw off the MPG as well, and it is the simplest to check.

On the highway in the USA they have Mile Markers. reset the truck odometer to zero as you pass one of them at 60 MPH and run 3 to 5 miles. Check to make sure that it takes you 3 to 5 min (use a stop watch) and that the odometer is reflecting the milage as well. If that is off let me know and we can calibrate using DDDL.

[jackalfa]

Thanks again Thecell, I already programmed all the VSS parameters, I even checked the speed with a GPS to compare speed accuracy with odometer and it's synchronized with the GPS and the laptop. I take all the ratios values from the manufacturers sites(transmissions and axles).
Just in the transmission value I have a little doubt, before I change parameters all the trucks was reading 1 in the "Top Gear Ratio" but the info in the transmission site (model FR-14210B) gives me .74 (I changed it to 1), but it seems that from factory it was set to 1, this is the only parameter I have a doubt, tires RPM and axle ratio are OK.

Thanks a lot for your time and patience to help me, regards.

[Lickety Split]

Thanks again Thecell, I already programmed all the VSS parameters, I even checked the speed with a GPS to compare speed accuracy with odometer and it's synchronized with the GPS and the laptop. I take all the ratios values from the manufacturers sites(transmissions and axles).
Just in the transmission value I have a little doubt, before I change parameters all the trucks was reading 1 in the "Top Gear Ratio" but the info in the transmission site (model FR-14210B) gives me .74 (I changed it to 1), but it seems that from factory it was set to 1, this is the only parameter I have a doubt, tires RPM and axle ratio are OK.

Thanks a lot for your time and patience to help me, regards.

jackalfa...you MUST have all parameters set to the actual spec of the hardware,ie: you said ratio is 1 but the website says your trans is .74...make sure,using the model/ser # and set it to what the actual spec is...good luck,hope this helps.

[Emgo]

jackalfa,
I spend too much time studying the tables in the ECM program with DCT. I remember this one "fuel per firing" I think this could be the one you need to change. You could do a block offset in ether direction to correct your problem. I don't think it will affect the actual fuel delivery, it's just the amount of fuel the ECM thinks the injectors are delivering. It's just a guess on my part. If this is wrong or someone has already said this please correct me. Take a look at the attached picture.

[jackalfa]

jackalfa...you MUST have all parameters set to the actual spec of the hardware,ie: you said ratio is 1 but the website says your trans is .74...make sure,using the model/ser # and set it to what the actual spec is...good luck,hope this helps.

Yes, is the only parameter I have a doubt, on all the trucks the value was in 1 and too, when I checked the website the value says .74 so it's what I'm going to do set all to .74 (in some trucks I already did that).

thanks for your response and time.

Correction: the value in VSS in all trucks was .74 and I changed it to 1 (Transmission FR-14210B)

[jackalfa]

jackalfa,
I spend too much time studying the tables in the ECM program with DCT. I remember this one "fuel per firing" I think this could be the one you need to change. You could do a block offset in ether direction to correct your problem. I don't think it will affect the actual fuel delivery, it's just the amount of fuel the ECM thinks the injectors are delivering. It's just a guess on my part. If this is wrong or someone has already said this please correct me. Take a look at the attached picture.

Emgo, thanks for taking the time to help me, I going to take a look at the table, but it suppose that the ECM should give the correct or with "X" percentage of error the consumed fuel with the original calibration from factory.
Thanks a lot it rally has been a lot of trouble to figure out the percentage of accuracy of the ECM in this issue. But I hope that thanks to you and all members we can come out with more knowledge to this issue.
Thanks again and regards.

[jackalfa]

jackalfa...you MUST have all parameters set to the actual spec of the hardware,ie: you said ratio is 1 but the website says your trans is .74...make sure,using the model/ser # and set it to what the actual spec is...good luck,hope this helps.

I made a mistake, the value in VSS in all trucks was before .74 then I changed it to 1 (transmission FR-14210B) when I saw this links:

http://www.roadranger.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&Rendition=Primary&&dDocName=RR_TRSL-0261

Eaton Fuller 10-Speed Transmissions (http://www.vibratesoftware.com/html_help/2011/Eaton_Fuller/Transmissions/eaton_10speed_trans.htm#FR-14210B)

Please let me know from where you get the .74 value, now I'm more confused about this value.

Thanks a lot, regards...

[Lickety Split]

I made a mistake, the value in VSS in all trucks was before .74 then I changed it to 1 (transmission FR-14210B) when I saw this links:

http://www.roadranger.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&Rendition=Primary&&dDocName=RR_TRSL-0261

Eaton Fuller 10-Speed Transmissions (http://www.vibratesoftware.com/html_help/2011/Eaton_Fuller/Transmissions/eaton_10speed_trans.htm#FR-14210B)

Please let me know from where you get the .74 value, now I'm more confused about this value.

Thanks a lot, regards...

you need to find out what is the "Final output ratio" of YOUR trans...use the model number from the tag on the case...take the model # and go to the website for the mfg and find the final output ratio...it will either be 1 or .73 a few were .74
if you cant find it,post ALL of the info from your tag here and i will try to help.
Mike

[jackalfa]

Lickety Split, thanks a lot for your response the transmission model is: FR-14210B.
I came out with the 1 ratio but if you can double check for me I would appreciate a lot. Thanks for taking the time to help me.
Regards...

[Lickety Split]

Lickety Split, thanks a lot for your response the transmission model is: FR-14210B.
I came out with the 1 ratio but if you can double check for me I would appreciate a lot. Thanks for taking the time to help me.
Regards...

that is in fact 1:1 which means it is a direct drive,you should enter 1 in the ratio...and make sure you have the rearend ratio correct,also the tire size,i always mark the tire then roll forward 1 turn and measure the distance to figure out how many revs per mile...there is a formula,i'll see if i can find it for you

[jackalfa]

Thanks a lot for your time Lickety Split...

[mondao]

if you want to know the tire revolutions in a km, try this
put a mark or piece of tape on the 6 o'clock position of your tire(side of it) and then make a mark on the ground next to it(starting point) , roll the truck forward or back one full turn so the mark is back at the 6 o'clock position again. make another mark on the ground. Now measure how far apart the 2
(a tip given to me by an old friend)

[ddmech]

Jack,to get your rev per mile,measure the hieght of your tire in inches.Multiply by pi which is 3.141.Take this answer and divide into 63360,which is the number of inches in a mile.You will be suprised how acurate this is.

[Lickety Split]

Jack,to get your rev per mile,measure the hieght of your tire in inches.Multiply by pi which is 3.141.Take this answer and divide into 63360,which is the number of inches in a mile.You will be suprised how acurate this is.

thanks ddmech,this is the formula i was thinking about earlier...works the same when measuring on the ground...63360 / inches per rev = revs per mile

[pichu2]

yes this transmission fr dont have over drve(74,73) this is direct cut in 1!!

[Thecell]

One additional option to check your speed / distance is to drive by one of the stationary radar / speed indicators.

[jackalfa]

I'm using a GPS to check distances and speeds and I can can say that it's very reliable method to this.
I still have problems with some DD DDEC V trucks ECMs that measures more gallons (using U.S. measurement) expended that actually used at the pump. For example one trip the truck burned 120 gallons at the pump but the ECM showed 162 gallons. This and all truck have been checked theirs parameters in VSS by others technicians and they don't find nothing wrong. We can't figured out why it don't have a good accurate percentage of actual fuel consumed, I will be very glad if it had a 5% of error in the fuel consumption report.

[jctech]

I'm using a GPS to check distances and speeds and I can can say that it's very reliable method to this.
I still have problems with some DD DDEC V trucks ECMs that measures more gallons (using U.S. measurement) expended that actually used at the pump. For example one trip the truck burned 120 gallons at the pump but the ECM showed 162 gallons. This and all truck have been checked theirs parameters in VSS by others technicians and they don't find nothing wrong. We can't figured out why it don't have a good accurate percentage of actual fuel consumed, I will be very glad if it had a 5% of error in the fuel consumption report.

Try using litres in the ECM and convert your pump volume to litres.

120 UK gallons is not far from 160 US gallons (144.2)
UK gallon = 4.5 litres, US gallon = 3.8 litres

depending on how the ECM is set up, it may be a software conversion factor that is incorrect.