With the constant increase in the price of fuel, more and more motorists pay great attention to the consumption of their vehicle. Although the exact fuel consumption of a car - or any motorized means of transport - varies according to several factors (the type of driving adopted, whether you drive in the city or on the motorway, tire pressure, etc.), calculating the average consumption is an extremely simple process.
Steps
Part 1 of 3: Calculate Fuel Consumption
Step 1. The formula for calculating fuel consumption is very simple and consists of dividing "the kilometers traveled by the amount of petrol or diesel used"
The fuel consumption of a vehicle is measured in kilometers traveled per liter. If you know the distance traveled and the number of liters used to travel it, to calculate the number of kilometers traveled with a single liter of petrol or diesel, simply divide the total distance by the total number of liters.
- If you need to, you can also do the calculations using miles and gallons as a reference.
- The best time to start tracking mileage is right after you fill up your car with fuel.
Step 2. Reset the vehicle's tripmeter immediately after filling up with fuel
All modern cars are equipped with this instrument which can be reset at any time to measure a partial distance. Normally, the button to reset the trip odometer is located directly on the dashboard or on the central dashboard. To reset it, just hold it down for a few seconds. Reset it immediately after filling the vehicle with fuel, then make a note of the kilometers traveled when you need to top up the next fuel. The data that will be indicated at the end will correspond to the number of kilometers traveled thanks to the last refueling carried out.
- After resetting, the tripmeter must show "0, 0 km".
- If your vehicle is not equipped with this tool, simply make a note of the total number of kilometers traveled so far, then mark it as "Starting Mileage". For example, if the odometer reads 10,000 km when refueling, you need to make a note of this value ("Initial mileage: 10,000 km").
Step 3. The next time you fill up with petrol or diesel, take note of the number of kilometers measured by the trip meter
Once stopped at the service station, record the number of kilometers traveled since the last full tank of fuel and record it in your notes under "Final mileage".
If your car is not equipped with a tripmeter, you can obtain the data in question simply by subtracting the "Initial mileage" from the number of kilometers currently recorded by the odometer. In this way, you will have obtained the number of kilometers traveled since the last refueling. For example, if the odometer reads 10,250, you will need to subtract 10,000 from that number. In this way, you will know that you have covered 250 km with the last refueling carried out
Step 4. Operate your vehicle until the tank is almost empty
You can perform this calculation regardless of how much fuel is left in the tank, but remember that the more fuel you consume, the more accurate the final figure will be.
Step 5. Make a note of the number of liters of fuel purchased with the last refueling
In this case it is important to completely fill the vehicle's tank and take note of the number of liters of fuel that have been purchased. This data represents the "Fuel used" to travel the distance indicated in the previous step.
It is very important to fill the vehicle tank completely for the calculation to be correct. Otherwise you won't be able to know exactly how much fuel you have used since the last refueling
Step 6. Divide the kilometers traveled by the amount of fuel used to travel them
In this way you will calculate the consumption of the vehicle, i.e. the number of kilometers you have traveled on a single liter of fuel. For example, assuming that you have traveled 335 km using 12 liters of fuel, the consumption of the vehicle in question will be equal to 27.9 kilometers per liter (335 km / 12 l = 27.9 km / l).
- If you have measured in miles and gallons, the final result will be expressed in "miles per gallon" or "mpg". In Europe it is customary to express the fuel consumption of a vehicle in "liters per 100 km" (ie the number of liters of fuel needed to travel 100 km).
- In order to correctly measure the fuel used, it is necessary to carry out the measurements starting with the tank completely full and then carry out a complete top up again at the end of the test.
Step 7. Practical examples on calculating the fuel consumption of a vehicle
After filling up with fuel, the odometer of Luca's car indicates 23,500 km traveled. After using the car for several days, Luca goes again to his trusted gas station to top up the fuel. At this point, the odometer reads 23,889 km and 12.5 liters of fuel were used to refuel again. What was the fuel consumption of the vehicle?
- Fuel consumption = (Final mileage - Starting mileage) / Fuel used;
- Fuel consumption = (23,889 km - 23,500 km) / 12.5 l;
- Fuel consumption = 389 km / 12.5 l;
- Fuel consumption = 31.1 km / l.
Part 2 of 3: Calculating the Average Fuel Consumption
Step 1. Remember that fuel consumption varies according to the type of driving
For example, driving a vehicle while continuing to accelerate and brake causes higher fuel consumption than driving at a steady, smooth, and smooth pace. This is the reason why consumption on the motorway is significantly lower than that measured in large cities.
- The "cruise control" (it is a tool that allows the automatic speed adjustment of a vehicle) can be useful for keeping fuel consumption under control.
- Fuel consumption increases as driving speed increases.
- Since the climate control or air conditioning system operates on the energy produced by the engine, keeping them switched off helps reduce fuel consumption.
Step 2. To calculate the average fuel consumption of a vehicle, repeat the procedure described in the previous section of the article several times
In order to have a more accurate view of the fuel consumption situation of your car, you need to collect as much data as possible. Driving longer and repeatedly can give you a more reliable picture of your car's average fuel consumption by eliminating or significantly reducing possible "errors" in measurements.
For example, let's say we want to calculate fuel consumption on a day on mountain roads. In this case, consumption will be higher than normal due to the continuous ups and downs that are normally encountered along mountain roads
Step 3. Reset the tripmeter after filling the vehicle with fuel
Complete this step and do not touch the tripmeter again until the next refueling. If your car does not have a trip meter, take note of the number of total kilometers, indicated by the odometer, when you refuel for the first time.
Step 4. Make a note of the number of liters of gasoline or diesel you purchase at each refueling
To get a more accurate measurement of fuel consumption, you need to know the exact amount of gasoline or diesel you use to cover a certain distance. Each time you top up fuel, make a note of the number of liters purchased.
Step 5. Drive normally for several weeks
Remember that it is very important to avoid resetting the tripmeter for the entire period under review. Make sure to refuel at least 3-4 to get the most accurate data possible. Try to carry out this test during a month of normal use of the vehicle, as driving for a long time on the motorway or in days of unexpected heavy traffic could also significantly change the final result.
During the intermediate refueling, you will not necessarily have to fill up, however you will have to make a note of the liters purchased each time
Step 6. At the end of the test period (2-3 weeks), do a full refueling of the vehicle's tank
When you are ready to make the final calculations, fill up the car, then make a note of the number of liters entered.
Step 7. Add up the number of liters of fuel purchased at each refueling
This way you will get the total number of liters of petrol or diesel that you used during the whole test period.
Assuming that you have made three refuelings of 12, 3 and 10 liters respectively, this means that a total of 25 liters of fuel have been used
Step 8. Divide the total number of kilometers traveled by the number of liters of fuel used to cover that distance
Rely on the tripmeter to figure out the number of kilometers traveled, then divide it by the number of liters of fuel purchased. This way you will get the average fuel consumption of your vehicle during the time period examined. While the number of kilometers traveled during the test is accurate, the average fuel consumption you'll get from the calculation is only an estimate - albeit quite accurate.
For example, assuming that 25 liters of fuel have been used to travel 500 km during the period under review, the average fuel consumption will be 20 km / l (500 km / 25 l = 20 km / l)
Step 9. Remember that the average fuel consumption reported by car manufacturers is almost always overestimated
By law, all car manufacturers are required to report the average fuel consumption of each of their vehicles. However, these are only estimates, which are often lower than the real figures. You can go back to the data declared by the manufacturer of your car by carrying out a simple online search, but to get the real values you will have to carry out the test described in this article yourself.
If the values you have obtained from your calculations are very different from those declared by the manufacturer of your car, it is very likely that there is a technical problem, so go to a mechanic as soon as possible to carry out a thorough check
Part 3 of 3: Reduce Fuel Consumption
Step 1. Do not use the air conditioner or air conditioning when it is not strictly necessary
The car air conditioning system uses the energy produced by the vehicle's engine, thus helping to increase fuel consumption. Set an internal temperature that is only a few degrees lower than the external temperature, or turn off the air conditioning system completely once the cabin is cool. This way you can manage your fuel consumption more efficiently.
Keeping the car's air conditioning system at its maximum cooling capacity at all times can increase fuel consumption by as much as 25%
Step 2. Always obey the speed limits
Remember that the faster you go, the more fuel you consume. This is not a negligible variation; over 80 km / h, every 5 km / h speed increase is equivalent to paying around 10 euro cents more for every liter of fuel.
Step 3. Drive regularly
It takes a lot more energy to get a vehicle moving than to keep it moving. This means that most of the fuel is consumed during acceleration, so try to keep the pace as constant as possible, without suddenly changing speed or overtaking.
Try to brake or accelerate smoothly and progressively. To avoid hard braking, start decelerating early to give you more space and more time to stop the vehicle
Step 4. Use the "cruise control" whenever you can
This instrument is designed to automatically manage the cruising speed of a vehicle in order to keep it as constant as possible. This improves engine efficiency while reducing fuel consumption.
Step 5. Turn off the engine when you are stuck in traffic
Keeping the vehicle running when stationary is simply a waste of fuel. Whenever possible, turn off the engine to save valuable fuel.
Step 6. Avoid mounting roof racks or roof boxes (also called roof boxes)
These bulky objects worsen the aerodynamics of the vehicle by significantly increasing its resistance to air; consequently, slowing down the normal running of the vehicle causes increased fuel consumption. Using a car trolley or trunk is a more fuel efficient option.
Step 7. Check your tire pressure regularly
Driving with flat tires can reduce the number of kilometers traveled by 0.3% for the same liters of fuel. Use the compressed air pumps present in all service areas to inflate the tires of your car to the optimal pressure indicated by the manufacturer in the maintenance booklet.
Some car manufacturers place adhesive labels on the inside of the driver's door or in the glove compartment, indicating the optimal pressure at which to inflate the tires
Step 8. Replace the engine air filter when required
It is one of the simplest and most economical ways to improve engine efficiency and reduce fuel consumption. Make sure you purchase the correct air filter for your car by referring to the make, model and year of manufacture. If you are having difficulty, ask the staff of any auto parts store for advice.
In the case of more modern cars, regular replacement of the air filter is not very helpful in improving engine efficiency. However, it improves its performance especially during acceleration
Advice
- Remember to replace the engine air filter at regular intervals, as required by the car's maintenance manual.
- Always respect the speed limits.
- Do not drive rough, accelerating and braking continuously. This is the best way to waste fuel and money (especially if you are driving a large vehicle such as an SUV or sedan).
- Whenever possible, avoid using your car's climate control or air conditioning.
- Regularly check the tire pressure referring to the values recommended by the manufacturer.
