How to calculate the machine's fuel consumption?

Dear sirs,

I have one question about excavators, dozers, rollers.

How to calculate the machine's fuel consumption? Can we have a formula for every machines?

Thank you.

kimson said:

Dear sirs,

I have one question about excavators, dozers, rollers.

How to calculate the machine's fuel consumption? Can we have a formula for every machines?

Thank you.

Click to expand...

It doesn't take a fancy formula. Next time you fuel, fill it all the way and make a note of the engine hours. When you go to fuel the time after that fill it up all the way again. Note your hours again. Subtract your first reading from the second one. That's your run time. Now divide the amount of fuel you just put in by your run time and that will give you your fuel burn. Do this over a long period of time and you'll find your average consumption.

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thank you birdog. I see your way but i wonder how the some manufacture can calculate but we not?
How can they calculate the minimun and maximun fuel consumption?

kimson said:

thank you birdog. I see your way but i wonder how the some manufacture can calculate but we not?
How can they calculate the minimun and maximun fuel consumption?

Click to expand...

It depends on how hard you work the machine. I push snow with a Deere 244J loader. The fuel consumption varies wildly depending on if I'm in one area or have to run across town and back.


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kimson said:

thank you birdog. I see your way but i wonder how the some manufacture can calculate but we not?
How can they calculate the minimun and maximun fuel consumption?

Click to expand...

The manufacturers take the fuel consumption at full load as recorded by their dynamometer when the engine is tested. This is equivalent to engine running at 100% all the time and is known as 100% Load Factor. Obviously machine engines do not run at full load constantly so the Load Factor in practice is always less than 100%. The manufacturers have experience from field studies (pretty much doing what the first person to respond to you said - it's no more scientific than that) of a range of load factors that result from different types of operation of any specific machine model. These are then grouped into 3 Load bands, Low, Medium, & High. For a dozer these bands would be: -

Low 35%-50% LF - Pulling scrapers, most agricultural drawbar, stockpile, coal pile and finish grade applications. No impact. Intermittent full throttle operation.
Medium 50%-65% LF - Production dozing in clays, sands, gravels. Push loading scrapers, borrow pit ripping, most land clearing applications. Medium impact conditions. Production landfill work.
High High 65%-80% LF - Heavy rock ripping. Push loading and dozing in hard rock. Working on rock surfaces. Continuous high impact conditions.

For other models the description of the typical work in each group will change, as will the LF for each range of operating conditions. In other words not all will be between 35-80%, it might be 20-80% or 20-50% depending on the type of machine.

Those numbers give you an estimate of what the machine will consume for a given type of work. The only way to confirm that estimate is to do a fuel consumption test in your specific operating conditions.

kimson said:

Dear sirs,

I have one question about excavators, dozers, rollers.

How to calculate the machine's fuel consumption? Can we have a formula for every machines?

Thank you.

Click to expand...

Fuel consumption figures for excavators are usually expressed as gallons per hour. To calculate the fuel consumption, simply divide the number of gallons of diesel required to fill the excavator's fuel tank by the number of hours that the machine has worked.

I don't know about other brands, but Cat has a lot of detailed information to be found in the Caterpillar Performance Handbook. In it you will find a section dealing with owning and operating costs, and the assumptions used to come up with them. It is important to read the assumptions carefully, as local factors are huge in estimating these costs.
For most classes of machines they will give an estimated fuel consumption in gallons or liters per hour of use, broken down into low, medium, and high with a brief description of the likely range for various types of work that the machines will typically perform.

The book mostly matches my actual experience when I am using the right factors, and if the book seems off, usually it is my usage factor that is not figured correctly. It takes some experience to get it right.

You can get a performance handbook from your local Cat dealer, or, like I did, find them on ebay. There are around 40 editions out now, and each one covers the machines available in the year it was written. I have a lot of older ones so I can always match up to the machines in my fleet.

JDOFMEMI said:

I don't know about other brands, but Cat has a lot of detailed information to be found in the Caterpillar Performance Handbook. In it you will find a section dealing with owning and operating costs, and the assumptions used to come up with them. It is important to read the assumptions carefully, as local factors are huge in estimating these costs.
For most classes of machines they will give an estimated fuel consumption in gallons or liters per hour of use, broken down into low, medium, and high with a brief description of the likely range for various types of work that the machines will typically perform.

The book mostly matches my actual experience when I am using the right factors, and if the book seems off, usually it is my usage factor that is not figured correctly. It takes some experience to get it right.

You can get a performance handbook from your local Cat dealer, or, like I did, find them on ebay. There are around 40 editions out now, and each one covers the machines available in the year it was written. I have a lot of older ones so I can always match up to the machines in my fleet.

Click to expand...

Jerry, The Cat Performance Handbook comes out every year. They're up to Edition 43 now (first one published was in 1971) and, sad person that I am, I have a copy of every one ...........

It doesn't take a fancy formula. Next time you fuel, fill it all the way and make a note of the engine hours. When you go to fuel the time after that fill it up all the way again. Note your hours again. Subtract your first reading from the second one. That's your run time. Now divide the amount of fuel you just put in by your run time and that will give you your fuel burn. Do this over a long period of time and you'll find your average consumption.

Fuel consumption figures for excavators are usually expressed as gallons per hour. To calculate the fuel consumption, simply divide the number of gallons of diesel required to fill the excavator's fuel tank by the number of hours that the machine has worked.

Great beneficial reply from mr birdog and alanmurfee

kiengine said:

It doesn't take a fancy formula. Next time you fuel, fill it all the way and make a note of the engine hours. When you go to fuel the time after that fill it up all the way again. Note your hours again. Subtract your first reading from the second one. That's your run time. Now divide the amount of fuel you just put in by your run time and that will give you your fuel burn. Do this over a long period of time and you'll find your average consumption.

Click to expand...

I'd respectfully point out that method only gives good information if the type of work the machine is doing remains the same over a long period of time. However for a contractor whose machines might be on a very hard job one week and a very light one the next it doesn't necessarily help. Fuel is one of the largest cost inputs into machine operation, and for any contractor to tender for a job he needs to know how much fuel his machine will burn in a specific type of use. Get it worng and he could lose money on the job, or even lose the tender in the first place if he over-estimates the fuel consumption.

On the upside average fuel consumption of the life of a machine can be used to predict component lives, as most components can be realted to the engine and most engine overhauls can be predicted by the amount of fuel they burn.

The Roadbuilders Assiosiation here uses the formula: 0.181 litres/HP-hr. to determine fuel consumption for pricing reasons. I have never tried it so im not sure if it works or not.

Nige said:

Jerry, The Cat Performance Handbook comes out every year. They're up to Edition 43 now (first one published was in 1971) and, sad person that I am, I have a copy of every one ...........

Click to expand...

Nige

I have all of them from edition #1 up to about #39. I have not kept up during the recession. When things recover I will have some back issues to hunt down. It took a while to get all of them gathered at first.

I must admit that since Edition 31 which was the first to come out as a paper copy or a CD I switched my attention from books to the digital media version.

I still like the feel of a good book. Never got into the digital versions, though they are a lot easier to store.

rule of thumb i stick to is .05 gal /hr per pto hp on na motors, .07 gph per pto hp on turbos
that said, my 301.5 burns up 6 gallons in a typical day at 17 hp 17hpx.05x8hrs is 6.8 gals, stop for lunch and figure some downtime / part throttle, and its pretty close.

1 full fuel tank = 1 full day in most cases.

I have several 963c machines and I have operators that will burn 20% more fuel per day but they get more than 20% more work done too...... I have one guy that will make the ole girl blow black smoke in forward AND reverse lol

Pj