Fuel consumption discussed, with formulae and tables provided

A correctly tuned diesel engine consumes fuel according to its power requirements.

Simple really, the more power you produce the more fuel you use.
Fuel consumption rate for many makes of naturally aspirated Diesel Engines can be found in a range between  0.380 & 0.450 lbs/hp hour; 172 & 181 grams/hp hour; 231 & 243 grams/kW hour.
This does not represent a big difference in fuel consumption per power unit between most normal diesel engines.
Fuel consumption for diesel engines is normally more difficult to express than for petrol engines because of the vast variability in possible applications. Applications like stationary industrial, marine, automotive, and earthmoving are examples of this variability. So it is normal to express this fuel consumption as a rate in terms of the weight of fuel consumed per unit of power produced. A real headache for plant managers!

Now even if an engine operates for long periods at a constant speed it seldom operates at its full rated power. On a dynamometer, engines seem to operate best at about 70% of expected maximum power, they seem quite tireless when operating there.
Still, asset control may be critical for profitable operation so we trust the following formulae & tables may be of some use.

You will observe in this spec sheet that the specific fuel consumption for the F4L1011 is given as 220 grams per kWh, but in actual fact it varies from about 231 to 241 grams per kWh with it's optimum consumption at 1800 rmp; i.e about 68% power.
You will also note that this engine falls within the specs already laid out for most diesel engines and is well suited to have the above table applied to it. Thus:
at continuous full power (44 kW @ 3000 rpm) it will use approx 12.8 liters per hour.

Deutz 2011 Naturally aspriated
Fuel Efficiency = 240 g/kW hour

The fuel consumption for the BF4L1011 varies between 228 to 218 grams per kWh. The latter 218 is when the engine is at full turbo boost. This averages approx 11% less fuel per kWh than the naturally aspirated engine.
So continuous full power (45 kW @ 2600 rpm) it will use approx 12.8 less 11% = 11.4 liters per hour.

Deutz 2011 Turbo
Fuel Efficiency = 213 g/kW hour

The Detroit Diesel 4-71 engine shows a fuel consumption between 0.430 to 0.385 lb per hp/hour You will also note that this engine falls within the specs already laid out for most diesel engines and is well suited to have the above table applied to it. Thus: at continuous full power (116 kW @ 2100 rpm) it will use approx 25.0 liters per hour.

Detroit 4-71 Naturally aspriated
Fuel Efficiency = 240 g/kW hour

The fuel consumption for the 4-71T varies between .370 to .355 lb/hp hour. At full turbo boost the consumption in terms of lb/hp hour is also better. This averages approx 24% less fuel per kWh than the naturally aspirated engine.
So continuous full power (157 kW @ 2300 rpm) it will use approx 46.9 less 24% = 34 liters per hour.

Detroit 4-71 Turbo engine
Fuel Efficiency = 182 g/kW hour