How much fuel does your machine burn, and how do you measure it?

Why there's no single number per model

The engine burns fuel according to the load the job demands. An excavator loading trucks with loose material works differently from the same machine breaking rock with a hammer or trimming a slope. That's why manufacturers talk about light, medium and heavy working conditions, and no heavy-machinery datasheet in the catalog publishes a single fuel figure.

Five things move consumption more than the model: the type of work, the power mode selected, idle time, maintenance condition (filters, wear parts, tires) and the way it's operated. If you compare two machines, compare them on the same job and with the same measuring method.

Method 1: tank-to-tank

It works for any machine, of any brand, with no technology. Fill the tank to the top and write down the hour-meter reading. Work normally for several days. Refill to the same level and note the liters that went in and the new hour reading. Divide liters by hours worked: that's your real consumption in liters per hour.

Two details make the difference: always fill in the same place with the machine on level ground, so «full» means the same thing; and measure a long period, several dozen hours, so a filling error weighs little. Keep the record per machine and per type of work.

Method 2: telematics measures it for you

On a Komatsu, KOMTRAX logs actual and average fuel use per hour, the remaining tank level, real working hours, idle time and hours in each operating mode (economy, power, breaker, lifting), according to Komatsu. You see it on your phone or computer, machine by machine and week against week, without relying on the daily report.

On Bobcat, Machine IQ shows location, hours, the last recorded fuel level and maintenance, according to Bobcat. That isn't the same as a per-hour figure: for that, cross the levels with the refills, or use the tank-to-tank method. If you run a mixed-brand fleet, the ISO 15143-3 standard lets you pull telematics data into one system.

Light equipment does publish its fuel use

On constant-load equipment, such as light towers, pumps or cut-off saws, the manufacturer can give a fuel figure because the engine almost always runs the same way. That's why several Wacker Neuson datasheets in the catalog include it. Use it to plan how much fuel to bring to site; even so, confirm it with your own measurement.

Where fuel goes without you noticing

Komatsu publishes in its fuel-saving guide how much habits weigh. These are Komatsu's figures, not our own measurements, but they show where to look first.

• Idling: one hour a day on a 20 t excavator, in auto-deceleration (3.3 L/h, 25 days a month), is about 990 liters a year, for a single machine.
• Trucks: raising the body at 80 % engine speed instead of full throttle uses 45 % less fuel on that maneuver.
• Tires: radials burn 5 to 15 % less than bias tires, thanks to lower rolling resistance.
• Dirty air filter: the engine breathes less and consumption rises about 3 %.
• Wear parts: with teeth and edges in good shape the bucket penetrates better and burns less fuel per cycle, according to Komatsu.

From liters per hour to cost per hour

Multiply your measured consumption by the fuel price you pay in your country: that's the fuel line of your cost per hour, one of the lines that weighs most in running a machine. Put it into the cost-per-hour calculator together with maintenance, wear and the operator.

If you also measure how many cubic meters the machine moves per hour, divide cost per hour by production and you get the cost per cubic meter. That number truly compares two machines or two ways of working: one that burns more per hour but moves much more can come out cheaper per cubic meter.

How to cut it without losing production

Saving fuel isn't working less, it's not burning it where it doesn't produce. This order usually pays off most:

• Shut down during long waits and check idle time every week.
• Use the work mode the task needs; maximum power isn't always necessary.
• Follow the filter and lubricant changes in the manufacturer's manual.
• Replace worn teeth, edges and tires on time.
• Train operators: the group's APMT Academy runs excavator and skid-steer operator courses.
• Compare operators on the same job with the per-hour fuel figure, not guesswork.

KOMTRAX in one minute

In this short from the group's channel you see how your Komatsu machines' data is checked instantly.

Where to activate telematics and get help

Grupo ConstruMarket is an authorized Komatsu distributor in El Salvador, Guatemala (CMARKET), Nicaragua and Panama. To add KOMTRAX users, review your fleet's fuel use or set up a maintenance plan, contact the after-sales team in your country with each machine's model and serial number. If you want the full calculation with your numbers, the fleet study works out cost per hour and per tonne with your operation's data.