# Fuel consumption calculations - amp page

## Fuel consumption calculations convert to liters per hour and US gallons per hour - amp

### Fuel Consumption units - conversion table

This table converts between the different units of fuel consumption one is most likely to encounter. It may be expanded in time to include other measures for fuel consumpton.

The choice of Specific Gravity of Diesel = 0.853 @ 15.5°C is quite arbitrary and will vary from time to time with different grades of diesel and in different countries; while some engine manufacturers may even specify a different specific gravity for their own tests, presumably for very good reasons. The ASTM for e.g. specify a density between 0.820 to 0.845 for EN590 diesel, while the European standard for the same fuel is between 0.820 and 0.860 kg/m3.

We have used it here because it was a value that Detroit Diesel used for some time, but all it really does here, is to establish a benchmark from where to express ourselves, and from where to work.

Table for diesel engine fuel consumption conversions

Basis: Specific Gravity of Diesel = 0.853 @ 15.5°C

Unit Multiply by to get
lbs / hp hour 0.533 liter  / hour
lbs / hp hour 0.1408 US gal / hour
US gal / hour 3.7854 liter  / hour
liter  / hour 0.2642 US gal / hour
kg  / hour 1.175 liters / hour
grams  / hour 0.001175 liters / hour
Regard all values as approximate

### Fuel Consumption calculations

Our tables are based on the following:
• Diesel - Specific Gravity = 0.853 @ 15.6°C
• i.e. 1 litre of diesel weighs 0.853 Kgs
• & so 1 Kg of diesel is 1/0.853 = 1.172 liter
• kg = lbs ÷ 2.2
• Kgs/hp hour = lbs/hp hour ÷ 2.2
• & so liter  /hp hour = Kgs/hp hour * 0.853
• & liter  /hp hour = lbs/hp hour ÷ (2.2 * 0.853)
• & so liter  /hp hour = lbs/hp hour ÷ 1.8766
• e.g. 0.40 lbs/hp hour = 0.40 ÷ 1.8766 = 0.2132 liter  /hp hour
Now to use the above data in practical examples:

An engine producing 310 hp at constant speed using 0.350 lbs of diesel per hp hour
uses the following amount of fuel:

310 x 0.350 = 108.5 lbs of diesel per hour
or
310 x 0.350 ÷ 1.8766 = 57.8 liter   per hour

An engine at constant speed producing 231 kW at that speed, & using 0.350 lbs of diesel per hp hour
uses the following amount of fuel:

231 x 1.341 x 0.350 ÷ 1.8766 = 57.8 liter   per hour

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