how to calculate disel consumpation

Easy reply is to drive the car/van/lorry until your fuel level meter is pointing to a line, ie half full ,go to the nearest fill up station and put 10 or 20 lts of fuel in, reset the trip meter and drive normally! when the fuel meter is in the same position as before, read the trip! with some basic calculation you can find out how many km/ltr or lts/100km or Miles/gallon you do.

TRIP METER READING/NUMBER OF LTS YOU PUT IN=Km/Ltr.

If you do this a few times, you can get a better idea as to what is you consumption

Hi, You can calculate the efficacy of engine

I can calculate the lts/100km, because I have just bought an old 4*4 and wanted to know the consumption! as for the efficiency, Out of my ball park! But I´m sure somebody else can help! I don´t think that a combustion engine is very efficient though, something like 30% or so! ( that is just what I think and maybe way off line!)

My last 4x4 truck got between 11 and 14 mpg but my 2wheel drive truck averages 23 miles mpg on the same roads.

A "Rule of Thumb" for diesel engine fuel consumption is;

1 gallon / per 20HP / per Hour.

IE: 10hp would use 1/2 gallon per hour.

50hp would use 2 1/2 gal/hr.

We have used this formula forever in the Marine field and it has been proven to be quite accurate.

An example would be my single engine trawler that burns 4 gal/hr at 8 knots.

This would work out to it taking 80hp to move the vessel at this speed.

Design calculation software returns the same HP requirement for this vessel.

Sometimes the old tried and true formulas are worth using.

My derar friends fuel consumption is always measured in Grams/Brekehorsepower/Hour at a selected ambient temperature.Volumeteric consumption will give falls Number.with the temperature Volume of fuel changes but weight remains constant.i have seen obnormally low consumption figs even when flow meters was used.Its an international practice to measure and express fuel consumption in grams only.Lesson learned is if you fill up your gas tank early morning when the ambient temperature is farely low you would be getting correct quantity of fuel.But if you fill your gas tank in the afternoon on a hot summer day chances are you would be paying for say 10Ltrs and might be getting less then 10ltrs.

crm

I would figure in resistance too. If a in a ship the incomming tide is hard to fight. On the road in winter the strom winds are tough on engery comsumption. That is where railroads have th advantage the weight they move has little resistance. Tire pressures, drivers ability, and too many issues to sit get a fixed number. There is not perfect working enviorment to set a fixed fuel rate. Each rate has to be individual.

The fuel is an issue too since all fuel contains so water.

What is the fuel consumption at other speeds?

Would you happen to have a reference for this information? Thanks!