Fuel consumption, experience from practice

Fuel monitoring devices

Fuel consumption plays an important role in the structure of transport costs and it is therefore necessary to pay special attention on it.
 
Each company having its own fleet is faced with the problem of how to precisely define and standardize the fuel economy of their vehicles. The problem occurs because the fuel consumption is influenced by numerous factors and there is the possibility of abuse, ie. disposal of fuel.
 
If vehicles in the fleet, are constantly working on one route or a longer period of time working on the same route, it is possible to test vehicles and test results accept as a norm that could be applied with a certain percentage of tolerance. From personal experience, I think it is acceptable 5% deviation in plus and minus.

The problem of determining norms, is especially evident when vehicles do not have a particular route, but every day and in the course of one day performing at various transport distances. So the vehicle can move through the city and outside the city, and the mountainous and plain terrain, the road with the modern and the road pavement with out-of-curtain. In these circumstances, it is very difficult, with acceptable accuracy and for a reasonable time to determine actual fuel consumption.

Even the vehicle manufacturers, faced with demands of its customers, offering solutions to this problem. In late nineties, to exploitation are released vehicles equipped with computers (ECU-s - Electronic Control Units) for some of its devices. On significant number of these vehicles, among other things, it is possible to monitor fuel consumption and that like:
 
1. fuel consumption at every moment while vehicle is moving and while vehicle standing, in litres/100km, litres/hour,
 
2. average fuel consumption since the vehicle is produced, in litres/100km, litres/hour,

3. total consumed amount of fuel since the vehicle is produced in litres.

Such an accurate and reliable device, almost entirely would solve the problem of fuel consumption at least when it comes to the misuse or misappropriation of fuel.
 
However, at about 50 vehicles, as there are in our fleet, which belong to different manufacturers, on none of the vehicles the device does not show the precise fuel consumption. In tests, we get deviations greater than 10%. Also, these deviations are not constant, but the two tests vary considerably for one and the same vehicle. These tests are performed, by ourselves, and under the supervision of official representatives of vehicle manufacturers.

As for us, such car manufacturers solutions were not satisfactory, we searched on.
 
A device that has helped us to solve the problem of misuse of fuel on vehicles, was  "EDM eco", produced by VDO.

 
This device connects with vehicle electronics and provides, inter alia, the following information:
 
1. fuel consumption at every moment while vehicle is moving and while vehicle standing, in litres/100km, litres/hour,
 
2. average fuel consumption since the vehicle is produced, in litres/100km, litres/hour,

3. total consumed amount of fuel since the vehicle is produced in litres.

Accuracy of data provided by EDM eco was 3% plus and minus, which was confirmed by the tests which was satisfactory with the standpoint of the owner of the vehicle fleet.
 
These devices are placed at about 50 vehicles in our fleet, and are exploited about 6 years. During operation, the devices were accurate and reliable. Deviations outside the limits prescribed by the manufacturer is not occurred except in the case of fuel abuse.
 

The next post will talk about how to test vehicle in terms of fuel consumption.