SE538820C2 - Air compressor control module for controlling an air compressor system of a vehicle and a method in relation to the control module - Google Patents

Description

538 820 US-6036449 relates to a system and method for air Compressor control wherein the air Compressor is loaded only when engine activities require it to be loaded or when free engine power is available to operate the compressor.

When the air pressure in the reservoir drops below a lower set pressure or when energy is "free," such as during downhill operations, the air governor exhausts the air signal allowing the air compressor to resume operation.

W0-98/07588 relates to device for controlling an air compressor in a motor vehicle, the engine of which is arranged to power the air compressor, with compressed air being fed to at least one user, comprising a control unit for the detection of a predetermined operational condition of the vehicle and for the control of the function of the air compressor.

An efficient and simple control of the function of the air compressor is provided, which permits the air compressor to be powered up to the higher pressure level during those operational states during which the engine of the vehicle in principle does not require any fuel (which for example is the case when driving downhill).

This in turn results in a reduced fuel consumption of the engine.

US-2013/0204490 relates to a motor controller unit that facilitates modifying pressure thresholds for an air compressor motor in a hybrid commercial vehicle as a function of vehicle pitch. lt may be desirable to reduce the state of charge (SOC) e.g., if the vehicle is nearthe top of the hill as made known through the GPS, in order to make room for charge generated by a regenerative braking event, e.g. once the vehicle crests the hill and begins traveling downhill.

US-2011/0259189 relates to a control device for a compressed air preparation device of a vehicle, wherein the control device outputs signals for adjusting feed phases and regeneration phases of the compressed air preparation device. This determination of the route sections with a compressed air demand which is expected to be increased can, according to the above statements, also be carried out on the basis of the map data and position data GPS and/or adaptively. ln particular, the end of the journey is often input directly into the GPS control 10 15 20 25 30 538 820 system and is therefore known. Furthermore, a self-learning vehicle energy management system is described that can provide profiles of the engine load and/or of the compressed air consumption not only for the same recurring routes but also for routes which are detected as being similar or equivalent.

US-2009/0193825 relates to a vehicle air-conditioner control system adapted to activate an air conditioner in response to a command from an air-conditioner remote controller before a passenger is onboard. The system controls the air conditioner based on a heat load detected by a heat load detector, controls the air conditioner to be set in a silent mode so as not to make the passenger feel uncomfortable due to an air-conditioning wind when a passenger-proximity deterrniner determines that the passenger is proximate to the vehicle.

And finally, WO-2014/106060 relates to a geographic specific controlling of a transport refrigeration system (TRS). The disclosed system automatically adjusts control parameters of a TRS according to local, regional and/or federal regulations on emissions, noise and/or other requirements applicable to a particular location and/or time, are provided. When the TRS is operating within a predefined geographic region at a specific time, control parameters or an operation mode of the TRS can be automatically adjusted so that emission and/or noise from the TRS can be compliant with the regulations applicable to that predefined geographic region.

The allowed sound level is today subject to specific regulations, in particular in urban areas. When an air compressor of a vehicle loads air the sound level is often high and not in line with the regulations as it might be disturbing for the environment. Although some of the above discussed prior art document take this aspect into account there is still room for further improvements, e.g. with regard to the overall energy consumption of the vehicle.

The object of the present invention is therefore to remove, or at least mitigate, the above-mentioned drawbacks of the presently used air loading methods or 10 15 20 25 30 538 820 systems of a vehicle and to achieve an improved control module and method in connection with an air compressor system that also fulfils the requirement of having low energy consumption, and to optimize the control of the compressor system in dependence of various parameters.

Summary The above-mentioned object is achieved by the present invention according to the independent claims.

Preferred embodiments are set forth in the dependent claims.

According to a first aspect the present invention relates to an air compressor control module as defined in the first independent claim.

According to a second aspect the present invention relates to method in connection with the air compressor module, the method is defined in the second independent claim.

The present disclosure relates to providing an intelligent air compressor control module for controlling the air loading of the air compressor. The compressor control module has the capability to measure the position of the vehicle in order to detect when the vehicle is in a location that requires lower sound level, i.e. to adapt the air loading to the environmental requirements. The control module should also be configured to take into account approaching bus stops and the topology of the future route to be able to adapt the air loading such that an optimal/maximal pressure within the air compressor is present when passing through a low sound level zone.

The air compressor control module is also configured to detect the distance to the next down-hill in order to wait until then to start the air loading, provided that the air pressure is above a predetermined critical low air pressure threshold. The reason is to be able to use energy that may be generated when the vehicle is driving downhill. 10 15 20 25 30 538 820 Two main advantages are obtained by the Compressor control module according to the present invention.

Firstly, by implementing a predetermined air loading strategy in an air compressor control module, the sound level of the air loading of the air compressor is adapted to the position of the vehicle, i.e. if the vehicle is within a low sound level zone no air loading is performed.

Secondly, the compressor control module is configured to optimize/plan, by implementing the air loading strategy, the air loading of the air compressor with regard to the energy consumption of the vehicle.

Brief description of the drawinds Figure 1 is a schematic illustration of a vehicle provided with an air compressor control module according to the present invention.

Figure 2 is a schematic block diagram illustrating the air compressor control module according to the present invention.

Figure 3 is a flow diagram illustrating the method according to the present invention.

Figure 4 shows four time diagrams illustrating various aspects of the module and method according to the present invention.

Detailed description The invention will now be described in detail with references to the appended figures. Throughout the figures like or similar items have the same reference signs.

With reference to the schematic illustration in figure 1, a vehicle 4 is illustrated, in this case a bus, comprising an air compressor system 6 being arranged to provide pressurized air 8 (see figure 2) to air powered systems 10 of the vehicle. An air compressor control module 2 is provided for controlling the air compressor 10 15 20 25 30 538 820 system. The vehicle may be a bus, a cargo vehicle, a truck, a car, or any other vehicle provided with a controlled air compressor system.

The schematic block diagram in figure 2 illustrates further parts of the air compressor system 6 and of the control module 2.

An air compressor control module 2 for a vehicle 4 is provided, being configured to apply a control signal 12 to an air compressor system 6 of the vehicle. The air compressor 20 is preferably an engine-driven, piston-type air compressor. The driving power is illustrated by an arrow 22. lnlet air 24 is provided to the compressor and the compressed air 26 is applied to an air dryer 28.

Conventionally the air dryer is provided, that primarily functions as a desiccant which removes moisture from the compressed air and thereby prevents downstream freeze ups and corrosion of the air tubing's, air tanks and valve components. Compressed air 8 is then applied to various air powered systems 10, such as service brakes, air suspension, air operated doors, windshield wipers, etc. Normally one air tank is provided in connection with each air powered device.

The control module 2 is configured to receive at least one air tank pressure signal 14 including pressure values of at least one air tank of the air powered systems 10. The pressure is sensed in a conventional way by a pressure sensor arranged for measuring the relevant pressure, often within the air dryer 28. ln figure 2 the pressure signal 14 is schematically illustrated as being generated by the air dryer 28. However, the pressure signal or signals could also be generated by each of the air powered systems 10 and directly applied to the control module 2.

The module is configured to compare the pressure value with a number of pressure threshold values. A maximum air pressure threshold PMAX representing a maximum acceptable pressure of the air tank, a minimum air pressure threshold PMIN representing a minimum air pressure where the air compressor still could provide air pressure to power the systems connected thereto to work normally, and also the threshold level that would trigger an activation of the compressor in a conventionally working air compressor system. ln addition a critical air pressure 10 15 20 25 30 538 820 threshold PCRIT may be provided that represents a pressure level that the measured pressure should not be allowed to be below.

The control module 2 is configured to determine, generate and apply a control signal 12 to the air compressor system 6, to set the air compressor system in an on mode where the compressor is activated and outputs pressurized air 26, or in an off mode where the compressor is switched off and is essentially silent.

The control module 2 is further configured to receive a vehicle position signal 16 including the current position of the vehicle. The information is often obtained via the global positioning system (GPS), or from an equivalent system.

A future route of the vehicle is determined at least based upon the current position of the vehicle and an electronic map 18. The electronic map comprises map related information that includes information of low sound level zones, of topographical information, e.g. information of uphill and downhill slopes, and also route information, e.g. bus stop positions of a route for a bus, or information regarding the traffic situation (traffic jams or accidents, etc.). A low sound level zone being a predefined geographical area where regulations stipulate a maximal allowed sound level of vehicles within the zone. This could typically be along specified streets in a city, or larger urban areas.

The future route may be determined in a number of different ways. ln one typical example the route is a known route for a bus where also bus stops are indicated.

According to another example the destination is known and a suggested route is determined in advance. According to still another example previous routes have been stored and if any of those routes matches to the present route the future route is easily available. The future route is continuously determined by the control module. ln vehicles a communication network often is provided for handling the communication between systems within the vehicle. Signals required to achieve the control of the air compressor system is advantageously communicated via that communication network that preferably is a CAN-bus. The CAN bus (controller 10 15 20 25 30 538 820 area network) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer.

The CAN bus applies a message-based protocol, designed specifically for automotive applications but is now also used in many other applications.

When the future route is determined the control module is configured to determine a topology parameter and a sound level parameter of the future route. The topology parameter includes information of downhill and uphill slopes of the future route, and the sound level parameter includes information of low sound level zones of the route.

Then the control module is configured to determine the control signal 12 in dependence of the pressure values, the topology parameter and the sound level parameter, such that the air compressor system is set in an off mode at least when it is determined that the vehicle is in a low sound level zone, provided that predetermined control rules are fulfilled.

Thereby an air loading strategy is implemented where these various parameters are taken into account which results in an optimal control of the air compressor system of the vehicle. ln the following a number of different control rules will be disclosed.

One control rule includes taking into account the distance or travel time to a downhill slope when determining the control signal.

One control rule includes taking into account the distance or travel time to a low sound level zone when determining the control signal.

More in detail, for implementing these two rules also information must be determined and applied regarding the calculated rate of decrease of the measured air pressure based upon an estimated air power consumption of the air powered systems 10. And also an estimated travel time in a low sound level zone. 10 15 20 25 30 538 820 One control rule that includes comparing the measured pressure value with a predetermined critical air pressure level PCRIT, and if the measured pressure value is lower than PCRIT a control signal is generated to set the compressor system in an on mode.

A number of control rules related to the measured air pressure; e.g. that the air pressure never is allowed to be higher than PMAX, and never below PCRIT, irrespectively of the vehicle is within a low sound level zone.

With reference to the flow diagram in figure 3 a method in an air compressor control module will be described. The control module is arranged in a vehicle provided with an air compressor system being arranged to provide pressurized air to air powered systems of the vehicle.

The method comprises determining, generating and applying a control signal to the air compressor system, to set said air compressor system in an on mode or in an off mode where the compressor system is essentially silent.

The method further comprises receiving at least one air tank pressure signal including pressure values of at least one air tank of the air powered systems.

Regarding further description of the air compressor system it is referred to the above description with references to figures 1 and 2.

The method further comprises the steps of: -Receiving a vehicle position signal including the current position of the vehicle.

The position signal could e.g. be a GPS-signal.

-Determining a future route of the vehicle at least based upon the current position of the vehicle and an electronic map. This is discussed more in detail above.

-Determining a topology parameter and a sound level parameter of the future route. The topology parameter includes information of downhill and uphill slopes of the future route, and the sound level parameter includes information of low sound level zones of the route, where a low sound level zone being a predefined 10 15 20 25 30 538 820 geographical area where regulations stipulate a maximal allowed sound level of vehicles within the zone.

-Determining the control signal in dependence of the pressure values, the topology parameter and the sound level parameter, such that the air compressor system is set in an off mode at least when it is determined that the vehicle is in a low sound level zone, provided that predetermined control rules are fulfilled.

Detailed descriptions of various control rules are given above.

Figure 4 shows four diagrams to be used to illustrate various aspects of the present invention.

From top to bottom is shown: A diagram illustrating how measured pressure values (Y-axis) vary over time (X-axis). Three pressure thresholds, PMAX, PMIN and PCRIT, are indicated as dashed lines, and six points of time (A-F) are illustrated as vertical dashed lines which are common for all four diagrams.

The second diagram shows the mode of operation of the air compressor system, either ON or OFF.

The third diagram shows the topography of the route, where the Y-axis designates the vehicle's vertical position over sea level.

And, the fourth diagram shows any low sound level zones (LSZ) along the route.

Before point A the air compressor system is in mode ON keeping the air pressure at a maximal level. In point A the mode is switched to OFF and the pressure decreases. ln point B the pressure is PMIN and normally the mode should be switched to mode ON. However, along the future route, in point C, a downhill slope is identified and therefore the pressure is allowed to decrease below threshold PMIN. lnstead the mode is switched to ON in point C, which is where the downhill starts. Thereby the extra energy available from the vehicle's engine during the downhill slope will be used by the air compressor system, which in turn reduces the overall energy consumption of the vehicle. ln point D the pressure is PMAX and the mode is switched to OFF. Between points D and E the pressure decreases down to a level between PMAX and PMIN. Along the future route, in 10 10 15 20 538 820 point F, starts a low sound level zone where the low sound OFF mode is required.

Therefore, in order to have enough air pressure during the entire low sound level zone the mode is switch to ON well before point F to ensure maximal pressure PMAX in point F.

The present invention also relates to a computer program P (see figure 2) that comprises a computer program code to cause an air compressor control module as defined above, or a computer connected to the control module, to perform the method which is discussed above.

Furthermore, a computer program product comprising a computer program code stored on a computer-readable medium to perform the method as defined herein, when the computer program code is executed by an air compressor control module as defined herein, or by a computer connected to the air compressor control module.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims. 11

Claims (13)

10 15 20 25 30 538 820 a

1. An air Compressor control module (2) for a vehicle (4) provided with an air Compressor system (6) being arranged to provide pressurized air (8) to air powered systems (10) of said vehicle, the control module (2) is configured to determine, generate and apply a control signal (12) to said air compressor system (6), to set said air compressor system in an on mode or in an off mode where the compressor system is essentially silent, the control module (2) is configured to receive at least one air tank pressure signal (14) including pressure values of at least one air tank of the air powered systems (10), i n that the control module (2) is further configured to receive a vehicle position signal (16) characterized including the current position of the vehicle, and to determine a future route of the vehicle at least based upon the current position of the vehicle and an electronic map, and to determine a topology parameter and a sound level parameter of the future route, wherein the topology parameter includes information of downhill and uphill slopes of the future route, and the sound level parameter includes information of low sound level zones of the future route, wherein said control module is configured to determine said control signal in dependence of said pressure values, said topology parameter and said sound level parameter, such that said air compressor system is set in an off mode at least when it is determined that the vehicle is in a low sound level zone, provided that predetermined control rules are fulfilled.

2. The module according to claim 1, wherein one control rule includes taking into account the distance or travel time to a downhill slope when determining the control signal.

3. The module according to claim 1 or 2, wherein one control rule includes taking into account the distance or travel time to a low sound level zone when determining the control signal.

4. The module according to any of claims 1-3, wherein one control rule 12 10 15 20 25 30 538 820 includes comparing said measured pressure value with a predetermined critical air pressure level PCRIT, and if said measured pressure value is lower than PCRIT a control signal is generated to set the compressor system in an on mode.

5. The module according to any of claims 1-4, wherein said electronic map comprises map related information includes information of said low sound level zones, of topographical information, e.g. information of uphill and downhill slopes, and also route information, e.g. bus stop positions of a route for a bus.

6. A method in an air compressor control module for a vehicle provided with an air compressor system being arranged to provide pressurized air to air powered systems of said vehicle, the method comprises determining, generating and applying a control signal to said air compressor system, to set said air compressor system in an on mode or in an off mode where the compressor system is essentially silent, the method further comprises receiving at least one air tank pressure signal including pressure values of at least one air tank of the air powered systems, c h a r a c t e r i z e d i n that the method comprises the steps of: -receiving a vehicle position signal including the current position of the vehicle, -determining a future route of the vehicle at least based upon the current position of the vehicle and an electronic map, -determining a topology parameter and a sound level parameter of the future route, wherein the topology parameter includes information of downhill and uphill slopes of the future route, and the sound level parameter includes information of low sound level zones of the future route, and -determining said control signal in dependence of said pressure values, said topology parameter and said sound level parameter, such that said air compressor system is set in an off mode at least when it is determined that the vehicle is in a low sound level zone, provided that predetermined control rules are fulfilled.

7. The method according to claim 6, wherein one control rule includes 13 10 15 20 25 30 538 820 taking into account the distance or travel time to a downhill slope when determining the control signal.

8. The method according to ciaim 6 or 7, wherein one control rule includes taking into account the distance or travel time to a low sound level zone when determining the control signal.

9. The method according to any of claims 6-8, wherein one control rule includes comparing said measured pressure value with a predetermined critical air pressure level PCRIT, and if said measured pressure value is lower than PCRIT a control signal is generated to set the compressor system in an on mode.

10. The method according to any of claims 6-9, wherein said electronic map comprises map related information includes information of said low sound level zones, of topographical information, e.g. information of uphill and downhill slopes, and also route information, e.g. bus stop positions of a route for a bus.

11. A vehicle comprising an air compressor system and an air compressor control module according to any of claims 1-5.

12. A computer program P, wherein said computer program P comprises a computer program code to cause an air compressor control module according to claims 1-5, or a computer connected to said control module, to perform the method according to any of claims 6-10.

13. A computer program product comprising a computer program code stored on a computer-readable medium to perform the method according to any of the claims 6-10, when the computer program code is executed by an air compressor control module according to claims 1-5 or by a computer connected to the air compressor control module. 14