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5 ways to control fuel consumption

The economic crisis and the consequences of the coronavirus epidemic are hurting the transport and logistics industry and all companies that use cars, trucks, passenger cars and special equipment in their work. In this situation, the main conditions for survival: reducing fuel costs and increasing efficiency at a minimum cost. In this article, we will tell you in detail what solutions can help you do this.

Managers and employees of car fleets who have been working for several years are probably familiar with the current situation. This was the case in 2014-2015, and in 2008-2009. Each successive crisis proves that it is impossible to overcome difficulties in the field of transport without satellite monitoring systems for fuel consumption.

In the cost structure of most fleets, fuel accounts for an average of 30-35%. In transport and logistics and road construction organizations, this figure can reach up to 45-50%. Fuel is a parameter that directly affects the profitability of a business. Work without unnecessary costs and not at a loss allows a competent accounting policy, based on accurate information about the consumption of fuel and lubricants.

In practice, not all enterprises have organized professional control and accounting of fuel. Some of the existing approaches are outdated. Some managers do not attach any importance to this and even turn a blind eye to the machinations of employees. There are situations when modern systems of remote monitoring of the work of cars and employees are implemented in car fleets, but they either do not know how or do not want to use them. It often happens that the installed solutions are not effective for certain types of transport.

Our review will help you better understand the existing methods of control of fuels and lubricants. The material will be useful for both owners and managers of car fleets, as well as specialists of companies that install satellite monitoring systems.

1. Fuel consumption monitoring without satellite systems

Until now, many fleets do without GLONASS / GPS monitoring. Let's assume that the accounting and write-off of fuel in the company occur correctly, and it seems that the problem of fuel overspending does not bother. But can management confidently claim to have all the information? Probably not. Real control is when it is possible to compare the maximum of different readings and identify the causes of discrepancies.

For example, the calculation of fuel consumption according to the standards of the Ministry of Transport will not be objective, since these standards are extremely average and sometimes very different from the actual readings of a particular vehicle. If the actual flow rate is calculated from the odometer data, the accuracy will also be "lame". The error of these devices sometimes exceeds 15-20%, and drivers can "wind up" the mileage. If receipts for gasoline or diesel fuel are taken into account when writing off fuel, there is a risk that they are fake. And accounting for fuel cards does not always guarantee transparency, because drivers can collude with gas station employees.

Plus, none of the fleet is not immune from fuel discharges, gas stations past the tank and the machinations of excess. No less likely are idle times, the use of transport for personal purposes, or irrational operation, which leads to fuel overruns. Without auxiliary solutions, it is difficult to determine such facts, and it is impossible to prove direct theft.

2. Satellite monitoring without fuel sensors

For basic satellite monitoring, it is enough to install a professional GLONASS / GPS tracker, which transmits information about the movement of vehicles, including coordinates, speed and mileage, to the monitoring system.

The mileage recorded by the trackers is much more reliable than the readings of the standard odometer of the car. Therefore, satellite data can help to more accurately calculate fuel consumption and to produce objective of the withdrawal. Also, by comparing the mileage from the monitoring system with the waybills, you can find out whether drivers attribute mileage.

At the same time, basic monitoring allows you to analyze the factors that directly affect the volume of fuel consumption. Due to the information about all the details of the transport operation (compliance with routes, visiting geofences, following the schedule), you can assess how effectively the fleet's activities are built, and determine the reasons for overspending, including: “left” flights, non-production downtime, negligent performance of duties.

In many modern satellite monitoring systems, it is still possible to monitor whether drivers comply with the rules of economical and safe driving.But with only one tracker, you will not be able to find out about the real fuel consumption on the way, about the time, places and volumes of refueling, about drains from the tank and other frauds.

3. Control of fuel consumption using the standard sensor via the CAN bus

What is a CAN bus?This is an interface that provides information exchange between various sensors and electronic systems of the car, as well as third-party devices within a single CAN-network of the car (Controller Area Network). The CAN bus is present in all modern vehicles.The essence of this method of fuel monitoring is to connect the GLONASS / GPS tracker directly to the vehicle's control unit via the CAN interface.

This is done through a wired connection using contactless card readers. As a result, the tracker will receive data on fuel consumption from the standard fuel level sensor and transmit them to the monitoring system. CAN-reading also allows you to remotely monitor the operation parameters of other systems and units of the car (engine hours, pressure, temperature, etc.).

The main thing is that the cars support an open data transmission protocol.This is the easiest and most cost-effective way to remotely monitor fuel. But the standard fuel sensors themselves are imperfect – the error in their readings can be 15% of the tank volume. It is difficult to count on the accuracy in determining the time, places and volume of gas stations here.

Fleets that monitor fuel via the CAN bus may experience “dead” zones (5-10% of the upper and lower tank volume), "false" drains, and incomprehensible rises/falls in the fuel schedule in the monitoring program. As a result, on vehicles with a large fuel consumption, the uncontrolled volume can reach 100 liters-first of all, on heavy trucks. And we must understand that this method does not always help to detect cases of direct theft of fuel and lubricants. The picture below shows the fuel level graph obtained from the standard sensor.

For comparison, the graph below shows the result of fuel control on one car using two different methods at the same time. The red color is the data received in the monitoring system from the standard fuel sensor. The blue color is the reading received from the Escort capacitive fuel level sensor (for more information about this method, see section 5 of the article).

Despite the obvious disadvantages, fuel consumption monitoring via the CAN bus is an acceptable option in cases where it is difficult to install more precise equipment due to the design features of the transport. And not everyone needs absolute accuracy. For example, in passenger car fleets, it is easier to set up the receipt of information from standard sensors and compare them with other satellite monitoring data, rather than spending money on more expensive and not so easy to install solutions.

4. Control of fuel consumption using a flow meter (DRT)

How does the flow meter work?This sensor is installed in the engine system of the car on the fuel line.The principle of operation of the flow meter is to determine the volume of incoming fuel and take into account the time of its consumption, so fuel consumption sensors (DRT) are also called flow sensors.Some models of flow meters can determine the engine operating time and fuel temperature.The readings recorded by the flow meters are transmitted to the on-board controller (GLONASS / GPS tracker) and fed to the monitoring system. The accuracy of the readings is very high: the error varies only at the level of 1-3%. This allows you to correctly maintain the actual accounting of fuel and lubricants and calculate the real fuel consumption rates for specific cars. But there are a few significant drawbacks:

  • the cost of fuel consumption sensors, their installation and maintenance costs are more expensive than every other method from this review;
  • flow meters are prone to contamination and require periodic cleaning, otherwise they can cause damage to the fuel system;
  • to control the drains through the "return", you need to install a second flow meter, or a more expensive differential sensor that monitors the fuel immediately in the supply and return lines;
  • flow sensors do not allow you to control the refueling and draining of fuel from the tank.

Again, let's compare the readings from different sensors that simultaneously monitored the fuel on the same vehicle. The blue graph is the data received from the DRT, and only the flow rate is visible here. The red graph is the readings recorded by the capacitive fuel level sensor, and here you can see when there were refueling and draining. At the same time, the difference in the accuracy of the flow readings is only 100 ml.

Despite these disadvantages, flow meters are often the best option for monitoring fuel on special equipment. First, the tank shape of many road, construction and agricultural vehicles is not always adapted for the installation of mortise screws (method No. 5). Secondly, high-quality flow meters are useful because they transmit information about engine hours and the state of the fuel system to the monitoring program – that is, car owners do not need to spend money on installing other sensors to monitor important parameters for special equipment.

5. Monitoring with a capacitive fuel level sensor

How does the fuel level sensor work?

The DUT is installed (crashes) into the tank of the car and records the change in the volume of fuel and lubricants. According to the principle of operation, they are also called capacitive sensors. The accuracy of the DUT is not inferior to the accuracy of the flow meter (97-99%). But to get objective data, it is important to properly calibrate the sensor and calibrate the tank at the installation stage.

Therefore, the installation of equipment should be trusted by professional installers.As in the case of DRT, the monitoring system receives the DUT readings from the tracker with which the sensor interacts. In the monitoring program, each change in the liquid level in the tank is displayed with a clear reference to the time and place. There are sensor options that do not require a connection to the on-board controller. These sensors have their own GPS/GLONASS module and a GPRS modem.

Together with obtaining high-precision data on the fuel level in the tank, Duets allow you to:

  • to fix the filling and draining fuel
  • identify false and incomplete gas stations
  • recognize micro-spills
  • identify the facts of the drain from the "return".”

There is an opinion that using the DUT does not reveal the fuel drain from the return line. But from the graphs and reports in the monitoring program, you can understand that this most likely happened.

The fuel level sensor is a universal tool for monitoring diesel fuel and gasoline on all cars and special equipment. But this method of control still has its limitations:

The measuring tube of the sensor can be cut to fit any height of the fuel tank, but if the height is less than 10 cm, then you will not get a normal picture of fuel consumption. Therefore, the method is not suitable for all passenger cars.

When installing DUT on special equipment, difficulties may arise if the tanks on the machines are of non-standard shape and with kinks. Then you will need to install two sensors, or still resort to another method of monitoring.

In elongated cans (trailers, road trains), there is a high probability of error due to fuel fluctuations at an angle. To get the average readings, you will need to set two DUT. This will increase the cost of equipment, but guarantees stable measurement accuracy.