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#1
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OM617 fuel consumption question
I'd like to know how much fuel a typical OM617 will consume within a time period and different throttle settings.
For example at idle, at full throttle/no load and at full throttle/full load. Gallons/hour, liters/minute, pints/week, any unit will be good. Trying to get approximate values, I'm researching the possibility to build a MPG gauge and would like to know the consumption so I can order fuel flow meters with a suitable range. I could go out and measure this with a measuring glass but it's difficult to measure the consumption with full load (moving at full speed uphill with a jar of diesel between your knees? ..)
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Tomas, Sweden 1966 Mercedes Benz 230S with OM617.912, automatic. Disk brakes from W108 1983 Mercedes Benz 300TD grey, OM617.912 and 5-speed manual 1983 Mercedes Benz 300TD blue 7-seater, OM617.912 and 5-speed manual |
#2
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It depends largely on how you measure it. If you loop the return then you only need to measure the input, from the tank, and the flow will be relatively small. The other way would be to use two flow meters, one for each the source and return lines, and subtract the difference. The problem with the first is that any air that gets into the pump will get trapped there with no return to the tank. The problem with the second method is that the flow rates that you measure will be much larger than the fuel usage, combine that with two flow meters instead of one, and the accuracy of the measurement will not be very good.
In short, the type of flow meter you get will depend on how you plan on measuring consumption. Eg. case 1: One low rate flowmeter, case 2: two high rate flowmeters.
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For Sale: 1982 MB 300TD 1995 Chevrolet Suburban 6.5TD Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel |
#3
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hmmmmm.....
Sounds like you just need to know the maximum fuel flow for the engine. If you can find the maximum delivery of the injector you can calculate the maximum fuel flow by multiplying the number of cylinders times the rpm divided by two. From there you can divide the drive shaft rpm by the fuel flow rate and scale it to get your fuel consumption.
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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons ) white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank) desert storm primer 63 T-bird "The Undead" (long term hibernation) http://ecomodder.com/forum/fe-graphs/sig692a.png |
#4
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Two flow meters is the way I intend to go (to get away from the air trap). Are you saying I can't get an accurate reading on fuel consumption if I subtract the return from the supply?
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Tomas, Sweden 1966 Mercedes Benz 230S with OM617.912, automatic. Disk brakes from W108 1983 Mercedes Benz 300TD grey, OM617.912 and 5-speed manual 1983 Mercedes Benz 300TD blue 7-seater, OM617.912 and 5-speed manual |
#5
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If anyone's interested having this for reference, here's my measurements:
Engine: OM617.910 Idle (warm engine): 0.0183L/minute (1.098L/hour) About 20% throttle (warm engine): 0.0396L/min (2.374L/H) Both measurements are 10-minute averages. I would like to get the full-throttle consumption but with no load it isn't possible, and driving around with a jar of diesel between my knees wasn't an option.. IF the injection throttle increase is linear a full throttle application would give something like 12L/hour but I find that a bit on the low side so I don't think I can extrapolate the 20%-figure onto a credible 100%-value.
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Tomas, Sweden 1966 Mercedes Benz 230S with OM617.912, automatic. Disk brakes from W108 1983 Mercedes Benz 300TD grey, OM617.912 and 5-speed manual 1983 Mercedes Benz 300TD blue 7-seater, OM617.912 and 5-speed manual |
#6
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This is good information. I do wonder what the fuel flow rate would be at constant highway speeds... Doable, on a flat road as the bucket wouldn't spill any diesel, right
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1983 300SD, 1999 200 cdi and 1998 1,6 (gasser) |
#7
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Quote:
My guess on the consumption at maximum load and maximum rpm's would be approx. 56L/hr. |
#8
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By that calculation you'd clean out the tank and be coasting to the side of the road if you drove flat out for barely 170 miles....I doubt that. I bet the lowest you could get would be around 15-16mpg....
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-diesel is not just a fuel, its a way of life- '15 GLK250 Bluetec 118k - mine - (OC-123,800) '17 Metris(VITO!) - 37k - wifes (OC-41k) '09 Sprinter 3500 Winnebago View - 62k (OC - 67k) '13 ML350 Bluetec - 95k - dad's (OC-98k) '01 SL500 - 103k(km) - dad's (OC-110,000km) '16 E400 4matic Sedan - 148k - Brothers (OC-155k) |
#9
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Quote:
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#10
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Perhaps.....I wonder how long the motor could run putting out maximum horsepower like that.....I'd imagine it exponentially takes "lifespan hours" out of it.....
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-diesel is not just a fuel, its a way of life- '15 GLK250 Bluetec 118k - mine - (OC-123,800) '17 Metris(VITO!) - 37k - wifes (OC-41k) '09 Sprinter 3500 Winnebago View - 62k (OC - 67k) '13 ML350 Bluetec - 95k - dad's (OC-98k) '01 SL500 - 103k(km) - dad's (OC-110,000km) '16 E400 4matic Sedan - 148k - Brothers (OC-155k) |
#11
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The C111-III averaged 17.6mpg traveling 186mph at 3400rpm with 230hp.
Its pretty difficult to get a 300D/CD/TD/SD below 20mpg without poor tuning or a fuel leak. My 300D got 25.8mpg on its first tank, with a leaking delivery valve, a bad injection pump and me not going easy with the throttle. Last edited by ForcedInduction; 05-25-2009 at 12:50 AM. |
#12
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The last time I got 20mpg highway I was grossing ~6,000 lbs and traveling 60-65 nonstop.
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$60 OM617 Blank Exhaust Flanges $110 OM606 Blank Exhaust Flanges No merc at the moment |
#13
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Yep........it's time at those power levels is definitely limited. I'd doubt that you'd get more than 250 hours under those conditions.
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#14
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Although Mercedes managed to get over 60 hours of continuous higher than stock output from two of theirs. Even longer if you consider the time not counted by the third car that hit the hedgehog.
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#15
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Sounds to me like there are still too many variable to get a definitive answer...
Won't those numbers change with temps, altitudes, tune up condition, etc? |
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