Horsepower hours per gallon- help me understand

[Kaliburz]

Well, I'm 'stuck' with the equipment I have.

The harvester (being a 4630 Ford/NH engine now) is doing fine. We keep it running about 1400-1600rpms and seldom do we hear it bog down, unless the belts get something jammed in roller and stops (then the hydro pump works.) During grape harvest, the 2030 and 2640 are pulling a 'trailer' that prob. weighs 1500lbs empty and once full, has 3-3.5 TONS of grapes in it. It's mainly moving along on JD gears 4 or 5 and we try to use the throttle to speed/slow, but keeping it between 900-1200 RPMs. That extra HP helps when loaded full and we hit a 'wet spot'.

(Imagine this: Once, my 2030 w/ the 'new' motor, pulling a 400 gallon speed sprayer-has air fan for spray dispersal- at 5th gear, 1500-1700 rpm. WE hit a really nice muddy section in the vineyard. I mean, muddy, top look like a puddle but bottom is that icky sticky stuff. Tank is FULL. I hit the mud, tractor slows due to slipping, but keeps on going. I gear up to 6th and mud starts to fly, keeping 1600rpm. Forward speed is remaining constant and I'm dragging the sprayer through the mud WHILE spraying to. Doesn't even bog down.)

During the season, it pulls a 6 foot wide, 3pt off set type disk w/ 22" blades (disks buried down), 5th gear, 1300-1500 rpms. Very seldom do we use PTO equipment, and if so, the brush is so light that we can chug along at 1500rpms, 5th gear also. The 2640 has a Hi/Lo lever (shift on the fly), which is about to one gear down shifting or up shifting (so says manual).

All of us who work on a budget will agree that it tends to get much harder when variables change. I use to buy steel for projects in slight 'excess', since I could store it for use on other projects. But w/ the cost of steel going up (and the fuel to transport it), I really think about how much steel I need to finish. I've resorted to buying 'surplus' stuff, good steel, but not at the same cost of 'new'. Sometimes I find deals, sometimes not. I've adapted projects based on what was available cheap, vs 'new'. As mentioned, I try to buy fuel when cheap (guessing that it might spike), but sometimes the opposite happens- gets cheaper closer to harvest vs middle of summer.

The only thing is, instead of budgeting to make a profit when one bills the customer, have to budget to have enough money to make it to after harvest and start the cycle all over again.

(Trend in labor costs in this state is for min wage to raise w/ the cost of living or standard of living. But historically, it's been $0.15 or so yearly. The '07 year, it jump $0.29 As of Jan 1, 2008, our min wage is $8.07, up from $7.92 (or 7.93), next closest is Oregon, just under $8.00)

 

[Kaliburz]

I read a PDF I found online, from Virginia Cooperative Extension, number 442-450. The tittle was "Gear Up & Throttle Down- Saving Fuel", published in 2001.

Any how, to sum it up (and I think most experienced tractor operators know this), full power/throttle is not needed all the time. It said that using 65% of full rating is usually the best area to get the most fuel efficiency. Example would be, most JD's are rated at 2400/2500rpm. So, by their saying, 1500-1600 rpm is okay, so as long as the engine is not lugged/overloaded for that speed.

Heck, we've been doing that for YEARS....... And buried in the story, the 'lab coats' cop out by saying that each tractor is different, situation (ground conditions)..... six pages and they basically say, "Rely on your own experience to show how to save fuel."


Sometimes, I wonder why most clap when a lab coat makes a 'discovery', but the real world folks have been doing it since the dawn of time....... Is it something about city folk vs country folks still?

 

[Farmwithjunk]

I read a PDF I found online, from Virginia Cooperative Extension, number 442-450. The tittle was "Gear Up & Throttle Down- Saving Fuel", published in 2001.

Any how, to sum it up (and I think most experienced tractor operators know this), full power/throttle is not needed all the time. It said that using 65% of full rating is usually the best area to get the most fuel efficiency. Example would be, most JD's are rated at 2400/2500rpm. So, by their saying, 1500-1600 rpm is okay, so as long as the engine is not lugged/overloaded for that speed.

Heck, we've been doing that for YEARS....... And buried in the story, the 'lab coats' cop out by saying that each tractor is different, situation (ground conditions)..... six pages and they basically say, "Rely on your own experience to show how to save fuel."


Sometimes, I wonder why most clap when a lab coat makes a 'discovery', but the real world folks have been doing it since the dawn of time....... Is it something about city folk vs country folks still?

Farmers know "how". The engineers know "why". University studies don't discover anything new all that often, but they do document their studies and put them in black & white for us to read.

 

[Kaliburz]

Farmers know "how". The engineers know "why". University studies don't discover anything new all that often, but they do document their studies and put them in black & white for us to read.

Yup, I remember being told that grape 'black leaf' was caused by a Potassium deficiency. Yet, in all the years of applying fert, we NEVER put Potassium and the grapes were old. I figured they had enough.....

But, noticed that sometimes, black leaf showed up when a section got dried out by accident. Then just recently (seems like it), they say black leaf is related to water stress..... observed that long before I went off to be 'schooled'.

 

[kbowley]

I came across this topic and felt like chiming in on understanding g/HPh. If the manufacturer provides the specific fuel consumption in that format then, basically, here is how to figure how much fuel the engine will burn. Lets say you have a 10 hp engine and consumption is given at 188 g/HPh. since hp is a unit measured in minutes, convert fuel consumption to minutes; 60 min / 188 horsepower hours =0.32 gallons will be consumed to produce one horsepower for one hour. Next multiply the rated horsepower by the consumption; 10*.32 = 3.2 gallons of fuel will be consumed at full load in one hour. Lets say that engine is used on a lawn tractor and your plowing snow...figure a guess at how much of the engines capacity you are using. Lets say you guess your using about 70 percent of rated to push a foot of wet snow for an hour; .7*10 = 7 HPh = 7*.32 = 2.2 gallons an hour when working hard to push that heavy snow. When mowing the lawn you may average 25 percent capacity; .25*10=2.5 *.32=.8 gallons per hour. Simply put, divide 60 by the g/HPh then multiply by your best guess of how much horsepower you are using.

 

[SPYDERLK]

I came across this topic and felt like chiming in on understanding g/HPh. If the manufacturer provides the specific fuel consumption in that format then, basically, here is how to figure how much fuel the engine will burn. Lets say you have a 10 hp engine and consumption is given at 188 g/HPh. since hp is a unit measured in minutes, convert fuel consumption to minutes; 60 min / 188 horsepower hours =0.32 gallons will be consumed to produce one horsepower for one hour. Next multiply the rated horsepower by the consumption; 10*.32 = 3.2 gallons of fuel will be consumed at full load in one hour. Lets say that engine is used on a lawn tractor and your plowing snow...figure a guess at how much of the engines capacity you are using. Lets say you guess your using about 70 percent of rated to push a foot of wet snow for an hour; .7*10 = 7 HPh = 7*.32 = 2.2 gallons an hour when working hard to push that heavy snow. When mowing the lawn you may average 25 percent capacity; .25*10=2.5 *.32=.8 gallons per hour. Simply put, divide 60 by the g/HPh then multiply by your best guess of how much horsepower you are using.

HP is not a unit based on minutes. It is an amount of work done per unit time. A HP-hr is the amount of work done by a horsepower in an hr. The amount of HP-hrs per gallon is a function of the energy content of the fuel and engine efficiency. Diesel engines will cluster at some value; gasolene engines at another. However fast you are doing work [exerting HP] will govern your fuel use rate. ... 10HP with a 12HP-hr per gal engine ei: 10HP/12HP-hr/gal = 0.83gal/hr
larry

 

[ericher69]

I came across this topic and felt like chiming in on understanding g/HPh. If the manufacturer provides the specific fuel consumption in that format then, basically, here is how to figure how much fuel the engine will burn. Lets say you have a 10 hp engine and consumption is given at 188 g/HPh. since hp is a unit measured in minutes, convert fuel consumption to minutes; 60 min / 188 horsepower hours =0.32 gallons will be consumed to produce one horsepower for one hour. Next multiply the rated horsepower by the consumption; 10*.32 = 3.2 gallons of fuel will be consumed at full load in one hour. Lets say that engine is used on a lawn tractor and your plowing snow...figure a guess at how much of the engines capacity you are using. Lets say you guess your using about 70 percent of rated to push a foot of wet snow for an hour; .7*10 = 7 HPh = 7*.32 = 2.2 gallons an hour when working hard to push that heavy snow. When mowing the lawn you may average 25 percent capacity; .25*10=2.5 *.32=.8 gallons per hour. Simply put, divide 60 by the g/HPh then multiply by your best guess of how much horsepower you are using.

Think you forgot a decimal...

If 70% capacity is 2.2gal/hr then 25% capacity should be less not more; 0.8gal/hr?

Haven't checked the math but did notice this decimal error

Sent from my iPhone 5s 64Gb using TractorByNet

 

[buickanddeere]

Usually a diesel , gas turbine or a boiler operate at peak efficiency at or near full output.

 

[motownbrowne]

Funny choice of threads to revive. Got pretty nasty back there. "No I'm a general contractor", "no I am!"

Good grief.

A friend of mine just bought a 1973 (I think) JD 4320. It's rated at almost 8gal/hr. Glad I'm not fueling that thing. My Kubota and my 8ns seem to be about 1 gal/hr.

 

[MHarryE]

An 8N uses 2.1 gph at 23 PTO HP. A 4320 uses 8 gph at 117 PTO HP. The arithmetic says the JD is about 45% more efficient at full power. Probably why they don't make tractors like the 8N anymore, and also why gasoline engine tractors (other than lawn tractors) are rare as hens teeth.