WO2015088423A1

WO2015088423A1 - Method in connection with a fan control system

Info

Publication number: WO2015088423A1
Application number: PCT/SE2014/051436
Authority: WO
Inventors: Alexander Lindvall; Viktor ZIKA
Original assignee: Scania Cv Ab
Priority date: 2013-12-10
Filing date: 2014-12-03
Publication date: 2015-06-18

Abstract

A method in connection with a fan control system for a vehicle and comprising an analysis unit and a control unit. The fan control system is configured to generate a fan control signal for controlling at least one cooling fan on board the vehicle in order to cool at least one unit on board. The method comprises the steps of - receiving in the fan control system an operating parameter signal comprising at least one operating parameter related to one or more events along the vehicle's future itinerary (A), - analysing said at least one operating parameter by applying a set of operating parameter rules (B), and determining a cooling requirement factor which represents future cooling requirements for said at least one unit on board the vehicle along the future itinerary (C), - generating said fan control signal on the basis of said analysis and determined cooling requirement factor (D), the cooling being controlled proactively in such a way that said one or more events along the future itinerary will influence the control of the cooling fan at their respective times, - controlling the cooling fan by said fan control signal (E).

Description

Title

Method in connection with a fan control system Field of the invention

The present invention relates to a method in connection with a fan control system, and to a fan control system, according to the preambles of the independent claims. More specifically the method and the system relate to controlling a cooling fan for a vehicle while taking events on the vehicle's future itinerary into account.

Background to the invention

In vehicles there are various units and systems, e.g. the engine and the gearbox, which require cooling for them to function. One or more cooling fans are often used to provide the cooling directly or indirectly via a heat exchanger. The cooling effect of these fans depends inter alia on their rotation speed, which in today's vehicles is normally controlled on the basis of measurements of one or more temperatures related to the engine's coolant or the temperature of the gearbox, and the engine speed. Cooling fan control may also involve using temperature measurements from auxiliary brake systems, so-called retarders, and the outdoor temperature. The control of cooling fan speed is conducted in real time, i.e. a change in a regulating temperature will directly cause a change in fan speed.

The cooling effect is not always optimum in every different operating situation. The fan will sometimes run at a higher speed than is necessary in the respective conditions, potentially resulting inter alia in both energy consumption and noise levels being higher than necessary.

The patent specifications mentioned below describe various examples of how the regulation of the cooling may be conducted in vehicles.

US-4377989 describes an air-cooled combustion engine with a cooling fan which adjusts its operation to the surrounding air pressure, which is appropriate when operating at high altitudes because in such conditions the fan's cooling capacity decreases, which is counteracted by its speed being increased.

US-2002/066422 relates to a combustion engine with a cooling fan which has a variable speed. The fan may be controlled on the basis for example of the engine speed or the temperature of the gearbox oil. The fan's speed is minimised to be not greater than is required for sufficient cooling.

KR-20050038956 describes a way of preventing too high a speed of a cooling fan, and of reducing its noise level by regulating its speed by determining the fan speed which corresponds to the prevailing vehicle speed and engine torque.

US-4881494 relates to a method for controlling a cooling fan for a combustion engine in a vehicle on the basis of engine temperature and vehicle speed. Inter alia, the noise of the fan is reduced by operating it in such a way that it switches off when the vehicle is travelling at low speeds.

US-2006/0254540 describes a method for controlling a hydraulically operated fan in a motor vehicle. The speed of the fan is limited when the engine is running at or above an overspeed.

These known systems and methods represent various examples of how a cooling fan may be controlled to improve the cooling effect by basing its control on various measured parameters. The inventors have found that there is potential for further improvement in cooling fan control, inter alia to reduce energy consumption.

The object of the method and the cooling fan system according to the invention is to achieve better control of the cooling of the engine and other systems on board the vehicle and hence run the cooling fan with reduced energy consumption and an appropriate reduced noise level. Summary of the invention

The above objects are achieved with the method and the cooling fan system defined by the independent claims. Preferred embodiments are defined by the dependent claims.

The method and the fan control system pertain to a form of fan control which takes into account one or more events along a vehicle's future itinerary in order to determine the fan control applicable at their respective times.

The cooling requirement may be predicted and the cooling fan be controlled proactively on the basis of the information in one or more operating parameters such as expected vehicle speed, road gradient, stopping-place information, information about noise-sensitive areas, road intersections etc., either from data which the vehicle has itself recorded for a given route (as on urban buses) or from stored data (as on tourist buses).

This has various advantages, such as providing the vehicle with cooling which is better optimised for the respective operating situation and leads inter alia to reduced energy consumption and lower noise levels.

Brief description of drawings

Fig. 1 is a schematic block diagram illustrating a fan control system according to the present invention.

Fig. 2 is a flowchart illustrating the method according to the present invention.

Detailed description of preferred embodiments of the invention

The method and the fan control system in which the method is employed will now be described in detail with reference to the drawings.

The first part of the description refers to the schematic flowchart in Fig. 1 . The method is intended to be employed in connection with a fan control system for a vehicle, e.g. a bus, freight vehicle, works vehicle, car or some other kind of vehicle. The fan control system is configured to generate a fan control signal for causing at least one cooling fan on board the vehicle to cool at least one unit on board. The unit or units to be cooled may for example be the vehicle's

combustion engine or gearbox or other units on board. The fan control system comprises an analysis unit and a control unit, described in more detail below in connection with the block diagram in Fig. 2. The method comprises the steps of:

- The fan control system receiving an operating parameter signal representing at least one operating parameter related to one or more events along the vehicle's future itinerary (A). The operating parameter may for example pertain to information about calculated speeds for the future itinerary, information about the latter's altitude profile and information about locations or sections of road where noise levels are restricted. This will be discussed in more detail below.

- Analysing said at least one operating parameter on the basis of a set of operating parameter rules (B) and determining a cooling requirement factor which represents the future cooling requirement for said at least one unit on board the vehicle along the future itinerary (C). An operating parameter rule comprises one or more definitions needed for interpreting the respective operating parameter and for relating the operating parameters to one another in cases where two or more of them are used. Future vehicle speed and road altitude profile are examples of related operating parameters. The cooling requirement factor is a quantification of the cooling requirement and may for example be standardised as "1 ", meaning a "normal cooling requirement". If the cooling requirement factor is greater than 1 , the cooling requirement is higher than normal.

- Generating said fan control signal on the basis of said analysis and determined cooling requirement factor (D), thus providing proactive control of the cooling in such a way that said one or more events along the future itinerary will influence the control of the cooling fan at their respective times.

- Controlling the cooling fan by means of said fan control signal (E). In one embodiment the cooling requirement factor is determined substantially continuously. Alternatively it may be determined at predetermined points in time, at intervals which may be constant or vary. The order of magnitude of the intervals will range from seconds to minutes.

Fresh values of the cooling requirement factor are therefore calculated

continuously for the vehicle's future itinerary and will thus predict the future cooling requirements for the units on board. In calculating the cooling requirement factor, account may also be taken of variables measured in real time, e.g. the vehicle's load, current power offtake, sundry temperatures, etc.

So-called predictive cruise controls use knowledge of the altitude curve of the road ahead in conjunction with the vehicle's current location and data about its performance to calculate and control the vehicle's speed in an optimum way, inter alia from a fuel economy perspective. Vehicle speeds calculated in this way may also serve as one or more operating parameters used in the method for the fan control system.

The operating parameter may thus comprise calculated vehicle speeds for the future itinerary and the latter's altitude profile. The future itinerary is determined on the basis of information about the vehicle's destination and/or route in combination with map data and location data from a position determination system, e.g. a GPS. The future itinerary may for example be up to 2 km long, in which case the system will take events into account not more than 2 km ahead of the vehicle.

The operating parameter rules comprise definitions for identifying a coming uphill section of the future itinerary's altitude profile, in which case the fan control signal will be determined such that the fan increases the cooling beforehand, since it is known that the cooling requirement will increase uphill. In more detail, this is achieved, when a conning uphill section is identified, by determining the hill's length and gradient, and its position, i.e. its distance from the vehicle's current location. Similarly, the operating parameter rules comprise definitions for identifying a coming downhill section of the future itinerary's altitude profile. The cooling requirement for a heavy vehicle may increase downhill because various auxiliary brakes, e.g. retarders, have to be activated. In such cases the fan control signal is determined such that the fan increases the cooling beforehand, since it is known that the cooling requirement will increase downhill.

The analysis unit comprises also information about the vehicle's cooling

requirements in different operating conditions, e.g. when a hill with a certain gradient and length is to be negotiated. This information may for example be stored in the form of a table or be calculated by predefined formulae.

With access to this information it is possible to calculate a distance before the hill at which the cooling will need to increase. Increasing the cooling before the hill makes it possible to achieve more optimum and energy-efficient cooling than basing the cooling solely on measurements in real time. Knowing the length of the hill does for example make it possible to allow units which require cooling to reach higher temperatures for a predetermined amount of time, or for a

predetermined distance, e.g. at the end of an uphill section, on the basis that the hill will soon end and the cooling requirement decrease.

In contrast, if a downhill section on the future itinerary is identified, the fan may for example be controlled in such a way that the cooling decreases for a

predetermined amount of time, or a predetermined distance, before the downhill section, since the cooling requirement will be smaller downhill in certain operating situations.

The fan control signal thus primarily provides information for controlling the fan but may also comprise further information or control parameters, e.g. relating to altered limit values for temperature ranges, e.g. in the engine or the gearbox, such that the temperature may temporarily be allowed to rise. In another embodiment one or more operating parameters pertain to information about noise level restrictions for the future itinerary. This embodiment may be applied separately or in combination with that described above. When a bus comes to a halt at a stopping place the noise from the cooling fan may often be found very annoying. In this embodiment the operating parameter rules comprise controlling the fan so that its noise level drops to a predetermined level, or the fan is switched off completely, when the vehicle is at a predetermined location, e.g. a stopping place, or on a section of road, or at predefined times, with restricted noise levels, e.g. in a built-up area at night. At a point in time before, or a predetermined distance before, the vehicle reaches the location where the cooling fan is controlled to an output level at which its noise level drops, or the fan is switched off completely, the fan may preferably be controlled in such a way that its cooling effect temporarily increases. In other words, the control takes prior account of a future event, in this case a halt at a stopping place, in order thereby to reduce the cooling requirement when the vehicle is in the vicinity of the stopping place.

In one particular application the future itinerary is a predetermined route for the vehicle, e.g. the route of an urban bus, which may be stored beforehand in the analysis unit. Alternatively the routes which the bus serves may be stored in the analysis unit together with information about locations where the bus stops.

The analysis unit will thus store information about at least one predetermined location where the vehicle stops for a variable amount of time before moving on, or a predetermined section of road. The operating parameter rules will then comprise determining control of the cooling fan such that its noise level drops when the vehicle is on a predetermined section of the itinerary which comprises said location or section of road.

When a bus approaches a stopping place, the control may cause the noise level to drop at a predetermined distance or time before the stopping place and remain at the lowered level for a predetermined distance or amount of time after the stopping place.

The method described above relates to taking events on the vehicle's future itinerary into account in the control of the cooling fan at their respective times. The method described may of course be used in conjunction with present-day control methods which take inter alia into account the temperature for example of the engine or the gearbox at the time. The fan control system will now be described in more detail with reference to the schematic block diagram in Fig. 2. To avoid repetition, since the description of the method above has already covered the fan control system, that description will be cited generally in the following description of the fan control system. Fig. 2 illustrates a fan control system 2 for a vehicle 4 which may be a bus, a truck, a works vehicle or a car. The system is configured to generate a fan control signal 6 for controlling at least one cooling fan 8 on board the vehicle in order to cool 10 at least one unit 12 on board. The fan control system comprises an analysis unit 14 and a control unit 16, which may be separate physical units but may also be wholly or partly implemented in software.

The fan control system is configured to receive an operating parameter signal 18 representing at least one operating parameter related to one more events along the vehicle's future itinerary. This signal conveying the operating parameters will preferably be accessible via the vehicle's CAN (controller area network) bus.

The analysis unit 14 is configured to analyse said at least one operating

parameter by applying a set of operating parameter rules. An operating

parameter may for example pertain to information about calculated vehicle speeds for the future itinerary, information about the latter's altitude profile and information about locations or sections of road where noise levels are restricted.

The analysis unit is further configured to determine a cooling requirement factor which represents future cooling requirements for said at least one unit 12 on board the vehicle along the future itinerary.

The control unit 16 is configured to receive the results of the analysis performed by the analysis unit, e.g. the determined cooling requirement factor and

information about where and when the fan will need to increase or decrease its cooling effect.

The fan control signal 6 is generated by the control unit 16 on the basis of the analysis and the determined cooling requirement factor, causing the cooling to be controlled proactively in such a way that said one or more events along the future itinerary will influence the control of the fan at their respective times.

In one embodiment the cooling requirement factor is determined substantially continuously. Alternatively it may be determined at predetermined points in time, at intervals which may be constant or vary. The order of magnitude of the intervals will range from seconds to minutes.

Fresh values of the cooling requirement factor are therefore calculated

continuously for the vehicle's future itinerary and will thus predict the future cooling requirement for the units on board.

In one embodiment the operating parameter takes the form of calculated vehicle speeds along the future itinerary, which may be calculated in the same way as in so-called predictive cruise controls which take into account inter alia the future itinerary's altitude profile and the vehicle's current location.

The operating parameter rules comprise definitions for identifying a coming uphill section of the future itinerary's altitude profile, in which case the fan control signal will be determined such that the fan increases the cooling beforehand, since it is know that the cooling requirement will increase uphill. The operating parameter rules comprise inter alia definitions for calculating a distance before the hill at which the cooling will need to increase. The control of the fan does for example involve applying operating parameter rules comprising definitions which may temporarily allow higher temperatures for a predetermined amount of time for units which require cooling, e.g. at the end of an uphill section on the basis that the hill will soon end. This embodiment was discussed in detail above in the description of the above method, which is here cited, inter alia with regard to how control is conducted when a downhill section is identified.

In another embodiment the fan control system is configured such that the control of the fan takes noise level restrictions for the future itinerary into account and reduces the fan's output, or switches it off completely, where the restrictions apply. The operating parameter or parameters comprise in this embodiment information about noise level restrictions for the future itinerary.

The operating parameter rules then comprise controlling the fan so that its noise level will drop to a predetermined level when the vehicle is on a section of road, or at a specific location (e.g. a stopping place), where noise levels are restricted.

In one variant of this embodiment the future itinerary is a predetermined route for the vehicle and comprises at least one predetermined location, e.g. a stopping place, where the vehicle will come to a halt for a variable amount of time before moving on, or a predetermined section of road.

In this variant the operating parameter rules comprise conducting the control of the fan in such a way that its noise level will drop when the vehicle is on a predetermined section of the itinerary which comprises the respective location or section of road.

Further details of this embodiment appear above in the description of the method. The fan control system described above is intended to take events along the vehicle's future itinerary into account in its control of the cooling fan at their respective times. The system described may of course be used in conjunction with present-day control systems which take into account inter alia the temperature of, for example, the engine or the gearbox at the time.

The invention comprises also a computer programme comprising a programme code P (see Fig. 2) for causing a fan control system, or a computer connected to the fan control system, to perform steps of the method described above.

The present invention is not restricted to the preferred embodiments described above. Sundry alternatives, modifications and equivalents may be used. The above embodiments are therefore not to be regarded as limiting the invention's protective scope which is defined by the attached claims.

Claims

1 . A method in connection with a fan control system for a vehicle and configured to generate a fan control signal for controlling at least one cooling fan on board the vehicle in order to cool at least one unit on board,

c h a r a c t e r i s e d in that the fan control system comprises an analysis unit and a control unit and that the method comprises the steps of

- receiving in the fan control system an operating parameter signal comprising at least one operating parameter related to one or more events along the vehicle's future itinerary (A),

- analysing said at least one operating parameter by applying a set of operating parameter rules (B), and determining a cooling requirement factor which represents future cooling requirements for said at least one unit on board the vehicle along the future itinerary (C),

- generating said fan control signal on the basis of said analysis and determined cooling requirement factor (D), the cooling being controlled proactively in such a way that said one or more events along the future itinerary will influence the control of the cooling fan at their respective times,

- controlling the cooling fan by said fan control signal (E).

2. The method according to claim 1 , in which the determination of the cooling requirement factor takes place substantially continuously.

3. The method according to claim 1 , in which the determination of the cooling requirement factor takes place at predetermined points in time, the intervals between which are constant or vary.

4. The method according to any one of claims 1 -3, in which said operating parameter comprises calculated vehicle speeds for the future itinerary.

5. The method according to any one of claims 1 -4, in which said operating parameter comprises the future itinerary's altitude profile.

6. The method according to claim 5, in which the operating parameter rules comprise identifying a coming uphill or downhill section of the future itinerary's altitude profile, whereupon the fan control signal is determined such that the fan will increase or reduce the cooling beforehand according to the cooling requirement on the uphill or downhill section.

7. The method according to claim 6, which method comprises

calculating a distance before the hill at which the cooling will need to increase or decrease.

8. The method according to any one of claims 1 -7, which method comprises allowing units which require cooling to reach higher temperatures for a predetermined amount of time, e.g. at the end of an uphill section.

9. The method according to any one of claims 1 -8, in which said operating parameter comprises information about noise level restrictions for the future itinerary.

10. The method according to claim 9, in which the operating parameter rules comprise controlling the cooling fan in such a way that its noise level will drop to a predetermined level when the vehicle is on a section of road with restricted noise levels.

1 1 . The method according to any one of claims 1 -10, in which the future itinerary is a predetermined route for the vehicle and comprises at least one predetermined location, e.g. a stopping place, where the vehicle will come to a halt for a variable amount of time before moving on, or a predetermined section of road, and the operating parameter rules comprise controlling the cooling fan so that its noise level will drop when the vehicle is on a predetermined section of the itinerary which comprises said location or section of road.

12. A fan control system (2) for a vehicle (4) and configured to generate a fan control signal (6) for causing at least one cooling fan (8) on board the vehicle (4) to cool (10) at least one unit (12) on board,

c h a r a c t e r i s e d in that the fan control system (2) comprises an analysis unit (14) and a control unit (16) and is configured to receive an operating parameter signal (18) comprising at least one operating parameter related to one or more events along the vehicle's future itinerary, that said analysis unit (14) is configured to analyse said at least one operating parameter by applying a set of operating parameter rules and to determine a cooling requirement factor which represents future cooling requirements for said at least one unit (12) on board the vehicle along the future itinerary, and that said control unit (16) is configured to generate said fan control signal (6) on the basis of said analysis and determined cooling requirement factor, the cooling being controlled proactively in such a way that said one or more events along the future itinerary will influence the control of the cooling fan (8) at their respective times.

13. The fan control system (2) according to claim 12, in which the determination of the cooling requirement factor takes place substantially continuously.

14. The fan control system (2) according to claim 12, in which the determination of the cooling requirement factor takes place at predetermined points in time, the intervals between which are constant or vary.

15. The fan control system (2) according to any one of claims 12-14, in which said operating parameter comprises calculated vehicle speeds for the future itinerary.

16. The fan control system (2) according to any one of claims 12-15, in which said operating parameter comprises the future itinerary's altitude profile.

17. The fan control system (2) according to claim 16, in which the operating parameter rules comprise identifying a coming uphill or downhill section of the future itinerary's altitude profile, whereupon the fan control signal (6) will be determined such that the cooling fan (8) will increase or reduce the cooling beforehand according to the cooling requirement on the hill.

18. The fan control system (2) according to claim 17, in which the operating parameter rules comprise calculating a distance before the hill at which the cooling will need to increase or decrease.

19. The fan control system (2) according to any one of claims 12-18, in which the operating parameter rules comprise allowing units which require cooling to reach higher temperatures for a predetermined amount of time, e.g. at the end of an uphill section.

20. The fan control system (2) according to any one of claims 12-19, in which said operating parameter comprises information about noise level restrictions for the future itinerary.

21 . The fan control system (2) according to claim 20, in which the operating parameter rules comprise controlling the cooling fan (8) in such a way that its noise level will drop to a predetermined level when the vehicle (4) is on a section of road with restricted noise levels.

22. The fan control system (2) according to any one of claims 12-21 , in which the future itinerary is a predetermined route for the vehicle (4) and comprises at least one predetermined location, e.g. a stopping place, where the vehicle (4) comes to a halt for a variable amount of time before moving on, or a predetermined section of road, and the operating parameter rules comprise controlling the cooling fan (8) so that its noise level will drop when the vehicle is on a predetermined section of the itinerary which comprises said location or section of road.

23. A computer programme comprising a programme code P for causing a fan control system (2), or a computer connected to the fan control system (2), to perform steps of the method according to any one of claims 1 -1 1 .