Method for protecting an on-board electrical network of a truck

The invention relates to a method for protecting an on-board electrical network of a truck having a base-line equipment provided by a truck manufacturer, and having base-line loads having a current consumption, an auxiliary equipment fitted a posteriori by a truck body builder, and having auxiliary loads having a current consumption, and a battery. The method further comprises, when the engine of the truck is ON: determining that the engine is to be turned off, determining a total current consumption of the truck, determining the battery maximum capacity, if the total current consumption is lower than the battery maximum capacity, turning off the engine, and, if the total current consumption is higher than the battery maximum capacity, reducing the current consumption of at least one adjustable auxiliary load.

RELATED APPLICATIONS

The present application claims priority to European Patent Application No. 21171982.8, filed on May 4, 2021, and entitled “METHOD FOR PROTECTING AN ON-BOARD ELECTRICAL NETWORK OF A TRUCK,” which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This disclosure pertains to the field of controlling loads of an on-board electrical network of a truck, the truck comprising a base-line equipment provided by a truck manufacturer and an auxiliary equipment fitted a posteriori by a truck body builder, and the loads comprising base-line loads comprised in the base-line equipment and auxiliary loads comprised in the auxiliary equipment. In particular, this disclosure relates to a method for protecting the on-board electrical network of the truck and a truck in which said method is implemented.

BACKGROUND ART

In the truck industry, it is known that a truck is provided with a base-line equipment provided by the truck manufacturer. This base-line equipment includes all electrical loads necessary to the operation of the truck, such as air compressor, steering, lighting, etc. For example, it can be formed by a chassis equipped with a passenger's cabin and powertrain components. It is also known that this base-line equipment can be delivered to a truck body builder, for example located on another site. The truck body builder usually customizes the base-line equipment of the truck depending on use case and preferences by adding one or more auxiliary equipment (also known as BodyBuilder). For example, the auxiliary equipment can be additional lights, a garbage compactor, a tipping trailer, an aerial bucket, a cooling compartment . . . .

The on-board electrical network of the truck is designed to handle the current consumption of the base-line equipment fitted by the original truck manufacturer. This means that the alternator coupled to the internal combustion engine, the battery, the harness and the various relays are designed to handle the current consumption of the base-line electrical loads comprised in the base-line equipment. When the truck body builder installs the auxiliary equipment in the truck to adapt the truck to its specific use, the auxiliary equipment comprises auxiliary loads which increase the current to be provided by the on-board electrical network.

Normally, the truck body builder follows rules given by the original truck manufacturer to install the auxiliary equipment, so that the current to be provided by the on-board electrical network to the auxiliary loads can be supported by the on-board electrical network.

However, in a first situation where the truck body builder follows the rules, it can happen that in some modes in which the truck operates, the current consumption of the auxiliary loads become higher than the current that can be supplied by the on-board electrical network, especially in operating modes where the internal combustion engine is switched off and where only the battery supplies current to the on-board electrical network.

Furthermore, it also happens in a second situation, that the truck body builder does not follow the rules. Consequently, the current consumption of the auxiliary loads can become higher than the current that can be supplied by the on-board electrical network, especially in operating modes where the internal combustion engine is switched off and where only the battery supplies current to the on-board electrical network.

In each situation, when the auxiliary loads current consumption becomes too high compared to what the on-board electrical network can deliver, the voltage supply of the network drops. Some equipment of the truck go into a safety mode and stop working. One or more electronic control units (ECU) automatically reset.

Typically, truck can be fitted with auxiliary equipment to form a garbage truck. The garbage truck is generally provided with an electric compactor as auxiliary load. This electric compactor requires a lot of power to operate. Therefore, if the internal combustion engine is turned off while the electric compactor is operating, a lot of current is drawn from the battery, which can lead the on-board electric network to collapse. Typically, more and more trucks are provided with a Start & Stop function, whereby the internal combustion engine is turned off as soon as the truck reaches standstill. This is particular true for garbage trucks which stop many times during their mission. Accordingly, if the electric compactor is activated while the internal combustion engine is off, the battery may not be able to provide enough current and the on-board electrical network voltage can drop to a critical level.

There is therefore a need for protecting an on-board electrical network of trucks in every operating modes of the trucks, especially when the internal combustion engine is switched off and only the battery supplies power to the on-board electrical network.

In the patent application US2016/316621 A1, it has been proposed an energy management system for an agricultural vehicle arrangement comprising an electric power supply unit for the supply of a large number of electrical consumers with electric power and consumption monitoring unit for the determination of a total electric power demand dependent on an actual operating state of the electrical consumers. The consumption monitoring unit operably estimates the electric power supply that is available from the electric power supply unit and compares it to the determined total electric power demand in order to reduce the electric power supply to the electrical consumers as a function of assigned supply priorities when the available electric power supply is exceeded by the determined total energy demand.

This energy management system proposes a method for controlling the auxiliary loads to guarantee the operation of the electrical network. However, this energy management system cannot be used in every operating modes of the vehicle, especially when the internal combustion engine is off and the auxiliary loads are still operating.

It is an object of the present disclosure to propose a method for protecting an on-board electrical network of trucks, especially when the internal combustion engine is switched off and only the battery supplies power to the on-board electrical network.

SUMMARY

It is proposed a method for protecting an on-board electrical network of a truck, the truck comprising:an internal combustion engine;a base-line equipment provided by a truck manufacturer, and having one or more base-line loads connected to the on-board electrical network and configured to be supplied by the on-board electrical network, and to have a current consumption,an auxiliary equipment fitted a posteriori by a truck body builder, and having one or more auxiliary loads connected to the on-board electrical network and configured to be supplied by the on-board electrical network, and to have a current consumption,an alternator for supplying current to the on-board electrical network from the internal combustion engine anda battery having a battery maximum capacity, and connected to the on-board electrical network;the method comprising, when the internal combustion engine is ON:1) determining that the internal combustion engine is to be switched off,2) determining a total current consumption of the truck as the sum of the current consumption of the one or more base-line loads and the one or more auxiliary loads3) determining the battery maximum capacity,4) comparing the total current consumption to the battery maximum capacity and if the total current consumption is lower than to the battery maximum capacity, turning off the internal combustion engine and,if the total current consumption is higher than the battery maximum capacity, reducing the current consumption of at least one adjustable auxiliary load, selected from the one or more auxiliary loads, so that the total current consumption becomes lower than the battery maximum capacity or preventing the internal combustion engine from being switched off.

In this disclosure, the word “ON” is used to describe an activated status of a component or device. For example, the expression “the internal combustion engine is ON” means that the internal combustion engine is in a switched on state, i.e. the engine is running. In this situation, alternator is running and provides electrical current. Similarly, the word “OFF” is used to describe a deactivated status of a component or device. For example, the expression “the internal combustion is OFF” means that the internal combustion engine is in a switched off state, i.e. the engine is stopped (not running) In this situation, alternator does not provide any electrical current.

Under the phrase “battery maximum capacity”, it is understood a maximum current (expressed in ampere, A) that can be delivered by the battery irrespective of the remaining energy stored in the battery (expressed in ampere-hour, A.h).

This present method proposes to determine the current consumption of the auxiliary loads before the internal combustion engine is switched off. The internal combustion engine is thus turned off only if the total current consumption is lower than the battery maximum capacity, meaning only if the battery can supply the base-line loads and the auxiliary loads.

Otherwise, the current consumption of at least one auxiliary loads, named adjustable auxiliary load, is reduced, so that the total current consumption becomes lower than the battery maximum capacity. By “reducing”, it is to be understood that the current consumption of the at least one adjustable auxiliary load can be decreased, but the adjustable auxiliary load still work in a degraded mode, or the current consumption can be reduced to zero, and the adjustable auxiliary load is switched off. Once the current consumption of the adjustable loads is reduced, and the battery can supply the base-line loads and the auxiliary loads, the internal combustion engine is turned off. The on-board electrical network is thus protected when the internal combustion engine is switched off.

Alternatively, the internal combustion engine is prevented from being switched off. Then, the alternator carries on to deliver current to the on-board electrical network. The current supply of all the auxiliary loads can thus be ensured by the on-board electrical network, and the auxiliary loads continue to operate in a normal mode, without causing a voltage drop of the voltage supply.

Hence, by determining the current consumption of the auxiliary loads before deciding if the internal combustion engine can be turned off, it guarantees that the current consumption of the auxiliary loads is always adapted to the current that can be supplied by the on-board electrical network. It thus avoids that some equipment of the truck goes into a safety mode and stop working, or that one or more electronic control units automatically reset.

The following features, can be optionally implemented, separately or in combination one with the others.

According to one aspect, the method comprises, after determining that the internal combustion engine is to be turned off,S1b) determining if at least one of the one or more auxiliary loads is ON, andif at least one of the one or more auxiliary load is ON, continuing the method,if none of the one or more auxiliary loads is ON, turning off the internal combustion engine.

Indeed, when any one of the one or more auxiliary loads is OFF (in other words, in a switched off state), the battery can supply the base-line loads. Therefore, the method can by-pass the determination of the total current consumption and the battery maximum capacity, and the internal combustion engine can be turned off immediately. The method is thus accelerated.

According to one aspect, the method comprises, when the internal combustion engine is OFF and when at least one selected auxiliary load, selected from the one or more auxiliary loads is OFF,Sa) receiving an activation request to switch ON the at least one selected auxiliary load,Sb) determining the current consumption of the at least one selected auxiliary loadSc) determining a total current consumption of the truck as the sum of the current consumption of the one or more base-line loads and the one or more auxiliary loadsSd) determining the battery maximum capacity,Se) calculating an available capacity of the battery corresponding to the difference between the battery maximum capacity and the total current consumption andif the current consumption of the at least one selected auxiliary load is lower than the available capacity of the battery, switching on the selected auxiliary loadif the current consumption of the at least one selected auxiliary load is higher than the available capacity of the battery, preventing the selected auxiliary load from switching on, or turning on the internal combustion engine before switching on the selected auxiliary load.

Therefore, when the internal combustion engine is OFF, the method prevents a selected auxiliary load, corresponding to an auxiliary load which is OFF (in other words, which is in a switched off state) and which has been requested to be switched ON, from being switched ON, if the battery cannot supply enough current to the on-board electrical network. It thus avoids a voltage drop of the on-board electrical network that could occur if the selected auxiliary load were switched ON.

According to one aspect, the method comprises, when the internal combustion engine is OFF and when at least one selected auxiliary load, selected from the one or more auxiliary loads is OFF,Sa′) receiving an activation request to switch on the at least one selected auxiliary load,Sb′) turning on the internal combustion engineSc′) switching on the selected auxiliary load.

Therefore, when the internal combustion engine is OFF and when an auxiliary load, named selected auxiliary load, is requested to be switched on, the method provides that the internal combustion engine first turns on, to ensure that the alternator can deliver enough current to the on-board electrical network, before the selected auxiliary load is switched on. It thus avoids a voltage drop of the on-board electrical network that could occur if the selected auxiliary load were switched on whereas the internal combustion engine is OFF.

According to one aspect, the battery maximum capacity can be determined depending on at least one of the following parameters, including:the State of Charge (SoC) of the battery,the State of Health (SoH) of the battery;the temperature of the battery.

Over time, the battery maximum capacity evolves. Taking into account the state of charge and/or the state of health and/or the temperature allows to adapt the battery maximum capacity value as close as possible to the reality.

According to one aspect, the current consumption of the at least one adjustable auxiliary load is reduced using a relay, or a transistor, for example a MOSFET switch.

The relay allows to reduce the current consumption of the adjustable load to zero. When the relay is activated, the current supply of the adjustable load is stopped. The adjustable load is thus switched off. The transistor allows to reduce the current consumption of the adjustable load to a lower level above zero, so that the adjustable auxiliary load still works in a degraded mode

According to one aspect, the method is implemented while the truck is moving, in particular when switching to a fuel saving mode in which the truck is moving with the internal combustion engine off or at low engine speed.

This situation is met, for example, during “eco-Roll” phases, also known as “I-Roll” phases. Indeed, under these circumstances, vehicle can keep moving without any power from the engine, such as when driving on flat roads or downhill. During these phases, a freewheel function is automatically activated in order to cut fuel consumption that saves fuel. To further save energy during these phases, the engine can be turned off. The only energy source is then the battery connected to the on-board electrical network.

According to one aspect, an alert is sent to the driver when the current consumption of the at least one adjustable auxiliary load is reduced.

The driver is thus warned that the current consumption, and thus the current supply, of the adjustable auxiliary load is reduced

According to one aspect, the one or more auxiliary loads are each assigned to a predetermined supply priority and if the total current consumption is higher than the battery maximum capacity, the one or more auxiliary loads are selected as the at least one adjustable auxiliary load depending on the assigned predetermined supply priority.

Therefore, the current consumption of the auxiliary loads associated with a higher supply priority is reduced as late as possible.

According to one aspect, the current consumption of the one or more auxiliary loads is recorded

This allows to learn about the current consumption of the auxiliary loads and to know how often an auxiliary load is switched off.

The present disclosure is also directed to a truck comprising:an on-board electrical network;an internal combustion engine;a base-line equipment provided by a truck manufacturer, and having one or more base-line loads connected to the on-board electrical network and configured to be supplied by the electrical network, and to have a current consumption,an auxiliary equipment fitted a posteriori by a truck body builder, and having one or more auxiliary loads connected to the on-board electrical network and configured to be supplied by the on-board electrical network, and to have a current consumption,an alternator for supplying current to the on-board electrical network from the internal combustion engine anda battery having a battery maximum capacity, and connected to the on-board electrical network;
wherein a method for protecting the on-board electrical network of the truck according to present disclosure is implemented.

According to one aspect, the base-line equipment comprises a base-line electronic control unit configured to control the one or more base-line loads and the one or more auxiliary loads.

According to one aspect, the base-line equipment comprises a base-line actuator, the base-line electronic control unit being configured to control the base-line actuator andthe one or more auxiliary loads comprise a direct auxiliary load coupled to the base-line actuator,wherein, when the total current consumption is higher than the battery maximum capacity and the direct auxiliary load is selected among the at least one adjustable auxiliary load, the base-line electronic control unit is configured to activate the base-line actuator and the base-line actuator is configured to reduce the current consumption of the direct auxiliary load.

According to one aspect, the auxiliary equipment comprises an auxiliary electronic control unit communicating with the base-line electronic control unit and an auxiliary actuator, the auxiliary control unit being configured to controlled the auxiliary actuator, and

wherein the one or more auxiliary loads comprise an indirect auxiliary load coupled to the auxiliary actuator,

wherein, when the total current consumption is higher than the battery maximum capacity and the indirect auxiliary load is selected among the at least on adjustable auxiliary load, the base-line electronic control unit is configured to send a control message to the auxiliary electronic control unit, the auxiliary electronic control unit is configured to activate the auxiliary actuator and the auxiliary actuator is configured to reduce the current consumption of the direct auxiliary load.

DESCRIPTION OF EMBODIMENTS

In the figures, the same references denote identical or similar elements. For sake of clarity, various elements may not be represented at scale.

FIG.1shows a truck1equipped with a base-line equipment100provided by a truck manufacturer. The truck1is shown before the truck1is fitted with an auxiliary equipment200by a truck body builder. In the example shown onFIG.1, the base-line equipment is formed by a chassis101equipped with a passenger's cabin102and powertrain components103, and other components necessary to the operation of the truck1, such as air compressor, steering, lighting, etc. The truck1comprises an on-board electrical network10to which base-line loads110of the base-line equipment100are connected to operate the base-line equipment100. In particular, the base-line equipment100can comprise one or more base-line loads110. The base-line loads110are the loads used in the base-line equipment100such as in the powertrain components103or the above mentioned other components necessary to the operation of the truck1.

FIG.2shows the truck1after the truck1has been fitted with an auxiliary equipment200by a truck body builder. In the example shown onFIG.2, the auxiliary equipment200is a garbage compactor201. Therefore, the truck1fitted with the auxiliary equipment200forms a garbage truck1. Alternatively, the truck1could be fitted with other auxiliary equipment200such as additional lights, a tipping trailer, an aerial bucket, a cooling compartment, or any auxiliary equipment providing a specific function to the truck1.

The auxiliary equipment200comprises auxiliary loads210connected to the on-board electrical network10to operate the auxiliary equipment200. In particular, the garbage truck1shown onFIG.2comprises an electric compactor as an auxiliary load210. In particular, the auxiliary equipment can comprise one or more auxiliary loads210.

The on-board electrical network10is further schematically represented on the layout ofFIG.3. The on-board electrical network10supplies both the base-line loads110and the auxiliary loads210.

The truck1comprises an internal combustion engine and an alternator for supplying current to the on-board electrical network10, and thus to base-line loads110and to the auxiliary loads210, from the internal combustion engine, when the internal combustion engine is ON. A battery12is connected to the on-board electrical network10for supplying current to the on-board electrical network10, and thus to base-line loads110and to the auxiliary loads210, when the internal combustion engine is OFF.

The base-line equipment100comprises a base-line electronic control unit120for controlling the base-line loads110and the auxiliary loads210.

The auxiliary loads210which are added to the truck1by the truck body builder after the base-line loads110can be connected to the on-board electrical network10in different ways.

According to a first example, the base-line equipment110comprises a base-line actuator130controlled by the base-line electronic control unit120, and an auxiliary loads named a direct auxiliary load211coupled to the base-line actuator130. Alternatively, the auxiliary loads210could comprise several direct auxiliary loads211. Moreover, the base-line equipment110could comprise several base-line actuators controlled by the base-line electronic control unit120, each coupled to one or more direct auxiliary loads.

According to a second example, the auxiliary equipment200comprises an auxiliary electronic control unit220communicating with the base-line electronic control unit120, an auxiliary actuator230controlled by the auxiliary electronic control unit220and auxiliary loads named indirect auxiliary loads212coupled to the auxiliary actuator230. Alternatively, the auxiliary loads210could comprise only one indirect auxiliary load212. Moreover, the auxiliary equipment200could comprise several electronic control unit each communicating with the base-line electronic control unit120, and each controlling an auxiliary actuator coupled to one or more indirect auxiliary loads.

The on-board electrical network10needs to be protected, especially when, the internal combustion engine is to be switched off. A method for protecting the on-board electrical network10of the truck1is implemented in the truck1. This method is represented on the diagram ofFIG.4.

For example, the method is implemented while the truck1is moving, in particular when the truck is intended to be switched to a fuel saving mode in which the truck1is moving with the internal combustion engine off or running at low speed.

For the garbage truck1, it applies especially when the internal combustion engine is to be turned off as soon as garbage truck1reaches standstill.

When the internal combustion engine is ON, the method comprises a first step S1 consisting in determining that the internal combustion engine is to be turned off. For example, if the garbage truck1is equipped with a start & stop function, it is determined that the internal combustion engine is to be turned off when the speed of the garbage truck is below a predetermined threshold, or when the garbage truck1reaches standstill.

Once it is determined that the internal combustion engine is to be switched off, it can be determined in a complementary step S1b to the first step S1, if at least one of the auxiliary loads is ON. If none of the auxiliary loads is ON, then the internal combustion engine is turned off. Indeed, the battery12is designed to provide current supply to the base-line loads that are ON. If at least one of the auxiliary load is ON, the method proceeds to a second step S2.

This complementary step S1b is optional. It allows the next step of the method to be carried out only if it is necessary, i.e. only if at least one auxiliary loads is ON, and thus a risk of a voltage drop of the on-board electrical network exists if the internal combustion engine is turned off. If this complementary step S1 is not carried out, the method proceeds directly to the second step S2 after the first step S1.

In the second step S2, the total current consumption I_total of the truck is determined. The total current consumption I_total of the truck is defined as the sum of the current consumption of the base-line loads I_BL and the current consumption of the auxiliary loads I_AL. In the illustrated example, the current consumption of the electric compactor is taken into account in the total current consumption if the electric compactor is ON.

Then, in a third step S3, the battery maximum capacity I_max is determined. Under a battery maximum capacity, it is understood a maximum current (expressed in ampere, A) that can be delivered by the battery irrespective of the remaining energy stored in the battery (expressed in ampere-hour, A.h).

The battery maximum capacity I_max is determined depending on at least one of the following parameters, including:the State of Charge SoC of the battery12,the State of Health SoH of the battery12, reflecting the ageing of the battery12;the temperature T of the battery12.
The battery maximum capacity I_max is thus adapted throughout the use of the truck1, so as to be as close as possible to the real value.

Alternatively, the battery maximum capacity I_max can be a fixed predetermined value given by the specification of the battery12.

In a fourth step S4, the total current consumption I_total is compared to the battery maximum capacity I_max. If the total current consumption I_total is lower than the battery maximum capacity I_max, meaning that the battery12can supply current to all the base-line loads110and the auxiliary loads210which are ON, the internal combustion engine is turned off. The battery12then provides current supply to the base-line loads110and to the auxiliary loads210while the voltage of the on-board electrical network10remains in an operating range of the on-board electrical network10. In this case, the electric compactor can be supplied in current by the battery12.

If the total current consumption I_total is higher than the battery maximum capacity I_max, the current consumption of at least one adjustable auxiliary load, selected from the one or more auxiliary loads is either reduced, or the internal combustion engine is prevented from being turned off.

In the first alternative where the current consumption of the at least one adjustable is reduced, all the auxiliary loads can be selected as adjustable auxiliary load, and the current consumption of all the auxiliary loads is then reduced. Alternatively, the one or more auxiliary loads are each assigned to a predetermined supply priority and the one or more auxiliary loads are selected as the at least one adjustable auxiliary load depending on the assigned predetermined supply priority.

When the current consumption of the at least one adjustable auxiliary load210is reduced an alert is sent to the driver.

Moreover, the current consumption of the at least one adjustable load is reduced so that the total current consumption I_total becomes lower than the battery maximum capacity I_max. For reducing the current consumption of the adjustable load, the current consumption of the at least one adjustable auxiliary load can be either decreased, but still be above zero, or reduced to zero. When the current consumption is reduced, the adjustable auxiliary load can still work but in a degraded mode. When the current consumption is reduced to zero, the adjustable auxiliary load is switched off. For example, the electric compactor can be switched off.

In particular, the current consumption of the at least one adjustable auxiliary load is reduced using a relay, or a transistor, for example a MOSFET switch. When using a transistor, the current consumption of the adjustable auxiliary load is reduced to a lower level (but still above zero). When using a relay, the current consumption of the adjustable auxiliary load is reduced to zero and the current supply to the adjustable load is stopped.

If the direct auxiliary load211is selected among the at least one adjustable auxiliary load, the base-line electronic control unit120activates the base-line actuator130and the base-line actuator130reduces the current consumption of the direct auxiliary load211.

If the indirect auxiliary load212is selected among the at least on adjustable auxiliary load, the base-line electronic control unit120sends a control message to the auxiliary electronic control unit220. Then, the auxiliary electronic control unit220activates the auxiliary actuator230and the auxiliary actuator230reduces the current consumption of the direct auxiliary load212.

Any setups of the on-board electrical network10that would allow to reduce the current consumption of the at least one adjustable load is also encompassed by the present disclosure.

Once the current consumption of the at least one adjustable load is reduced, the internal combustion engine can be turned off, and the battery12then provides current supply to the base-line loads110and to the auxiliary loads210which are ON, while the voltage of the on-board electrical network10remains in an operating range of the on-board electrical network10.

In the second alternative where the internal combustion engine is prevented from being turned off, the alternator carry on to deliver current to the on-board electrical network10and ensures the current supply of all the auxiliary loads210and base-line loads110which are ON. Thus, the auxiliary loads continue to operate in a normal mode, without causing a voltage drop of the voltage supply. In the illustrated example, keeping the internal combustion engine ON enables the electric compactor to carry on operating.

The on-board electrical network10also needs to be protected when the internal combustion engine is OFF, and that at least one selected auxiliary load, selected from the one or more auxiliary loads is OFF and is requested to be activated. Indeed, when the internal combustion engine is OFF, only the battery12provides current supply to the base-line loads110and to the auxiliary loads210, and it must be determined whether the battery12can also provide current supply to the selected auxiliary load.

In a first embodiment represented onFIG.4, when the internal combustion engine is OFF, the method comprises an a-step Sa where an activation request to switch on the at least one selected auxiliary load is received. For example, the internal combustion engine is OFF, and the electric compactor is OFF, and a request is sent to switch on the electric compactor.

In a b-step, the current consumption of the at least one selected auxiliary load I_SAL is determined. It corresponds to the current consumption that the at least one selected auxiliary load has when it is ON. In the illustrated example, the current consumption of the electric compactor is determined.

In a c-step Sc, the total current consumption I_total of the truck1is determined. The total current consumption I_total is defined as the sum of the current consumption of the one or more base-line loads I_BL and the one or more auxiliary loads I_AL which are ON.

In a d-step Sd the battery maximum capacity I_max is determined. Then, in an e-step Se, an available capacity of the battery I_av is calculated. The available capacity of the battery I_av corresponds to the difference between the battery maximum capacity I_max and the total current consumption I_total. It corresponds to the maximum current supply that the battery12can provide in addition to the current supply that the battery12already provides to the one or more base-line loads I_BL and the one or more auxiliary loads I_AL which are ON.

If the current consumption of the at least one selected auxiliary load I_SAL is lower than the available capacity of the battery I_av, it means that the battery12can provide current supply to the selected auxiliary load. The selected auxiliary load is thus switched on. For example, the current consumption of the electric compactor is lower than the available capacity of the battery I_av, and the electric compactor is switched on.

If the current consumption of the at least one selected auxiliary load I_SAL is higher than the available capacity of the battery I_av, it means that the battery cannot provide current supply to the selected auxiliary load. Thus, the selected auxiliary load is either prevented from switching on, or the internal combustion engine is turned on before the selected auxiliary load is switched on.

In the first alternative where the selected auxiliary load is prevented from switching on, it avoids the battery to provide current supply to the selected auxiliary load as the selected auxiliary load remains OFF. The electric compactor remains OFF. The voltage of the on-board electrical network10thus remains in its operating range.

In the second alternative where the internal combustion engine is turned on before the selected auxiliary load is switched on, it allows the alternator to provide current supply to the on-board electrical network10instead of the battery12. Thus, the selected auxiliary load can be supplied in current without causing a voltage drop in the on-board electrical network10. The electric compactor is thus switched on after the internal combustion engine is turned on.

In a second embodiment represented onFIG.5, when the internal combustion engine is OFF, the method comprises an a′-step Sa′, where an activation request to switch on the at least one selected auxiliary load is received. Then, in a b′-step Sb′, the internal combustion engine is turned on. Finally, in a c′-step, the selected auxiliary load is switched on. Therefore, it is not determined if the battery12can provide current supply to the selected auxiliary load in addition to the addition to the current supply that the battery12already provides to the one or more base-line loads I_BL and the one or more auxiliary loads I_AL which are ON. The internal combustion engine is turned on before the selected auxiliary load is switched on. Therefore, the alternator provides current supply to the on-board electrical network10instead of the battery12when the selected auxiliary load is switched on. Thus, the selected auxiliary load can be supplied in current without causing a voltage drop in the on-board electrical network10. In this case, the electric compactor is switched only after the internal combustion engine is turned on.

It is to be understood that this second embodiment replaces all the steps from a-step Sa to e-step Se shown onFIG.4, but the first step S1 to the third step S3 remains identical.

The current consumption of the one or more auxiliary loads210is recorded. It is then possible to learn about the current consumption of each auxiliary loads210and to know how often an auxiliary load is switched off.