SE539280C2

SE539280C2 - Clutch by wire system with indication unit

Info

Publication number: SE539280C2
Application number: SE1550816A
Authority: SE
Inventors: Isacsson Robin; Skeppström Tomas
Original assignee: Scania Cv Ab
Priority date: 2015-06-16
Filing date: 2015-06-16
Publication date: 2017-06-13
Also published as: SE1550816A1; DE102016006534A1

Description

Clutch by wire system with indication unit Technical field The present disclosure relates to a clutch by wire system for a vehicle, and to a method in a clutch by wire system.

Background Historically, in vehicles there has been a mechanical connection between the clutch pedal and the clutch. This mechanical connection may be by a wire, a system of rods, or being hydraulically controlled or air-controlled connections.

If there is no mechanical connection between the clutch pedal and the clutch, a so-called clutch by wire (CBW) system is provided. In a CBW system a clutch pedal sensor is arranged to sense the position of the clutch pedal and the clutch is then controlled in dependence of the pedal position by an electrically controlled activator. In other words, the clutch activation is electrically and not mechanically controlled.

A clutch-by-wire system in a vehicle is disclosed in EP-2101074. The system is provided with an automatic clutch and a transmission control device controlling an automated transmission. The system includes a display device arranged to display the status of the gear position.

GB-21829002 relates to a clutch biting-point indicator for motor vehicle. The indicator is provided with bulb that is lit when either first of reverse gear is selected, and a switch is actuated by a roller attached to clutch pedal.

US-2005/073398 relates to a vehicle driveiine and warning system that is operable to monitor operation of primary warning device and actuate secondary warning device should indication be received that primary warning device has failed.

In a mechanically controlled clutch the driver senses the clutch state via the clutch pedal, e.g. the driver senses where the engagement point is.

In a clutch by wire system no such response, or feedback, may be obtained via the clutch pedal.

The object of the present invention is to remove this drawback and to achieve an improved and more user friendly CBW system.

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

Preferred embodiments are set forth in the dependent claims.

According to a first aspect the invention comprises a clutch by wire (CBW) system for a vehicle, comprising a clutch control module, a clutch pedal, a clutch pedal position sensor unit configured to measure the pedal position, to generate a pedal position signal including pedal position data, and to apply the pedal position signal to said clutch control module. The control module is configured to determine a clutch control signal including clutch control instructions in dependence of said pedal position data and one or many clutch control parameters, to generate said clutch control signal and to apply said clutch control signal to a clutch of the vehicle to control the clutch to be in a clutch state, wherein said clutch state is any state of the clutch from a fully engaged clutch state to a fully disengaged clutch state, and includes an engagement point state where the clutch is about to be engaged. The CBW system comprises an indication unit configured to generate an indication signal in dependence of said clutch control signal. The indication signal includes information representing the clutch state, and is a visual, an audible, or a tactile signal, or a combination of these, to indicate the clutch state to a user of the vehicle.

According to a second aspect a method in a clutch by wire (CBW) system for a vehicle is provided, comprising a clutch control module, a clutch pedal, and a clutch pedal position sensor unit. The method comprises: - measuring the pedal position, - generating a pedal position signal including pedal position data, - applying the pedal position signal to said clutch control module, - determining a clutch control signal including clutch control instructions in dependence of said pedal position data and one or many clutch control parameters, - generating said clutch control signal, - applying said clutch control signal to a clutch of the vehicle, - controlling the clutch to be in a clutch state, wherein said clutch state is any state of the clutch from a fully engaged clutch state to a fully disengaged clutch state, and includes an engagement point state where the clutch is about to be engaged, - generating an indication signal by an indication unit in dependence of said clutch control signal, wherein said indication signal includes information representing the clutch state, and is a visual, an audible, or a tactile signal, or a combination of these, to indicate the clutch state to a user of the vehicle.

A driver assistance is achieved by implementing the system and the method according to the present invention by indicating to the driver the exact state of the clutch, which e.g. is very helpful in order to assist the driver to perform a safe start off as the engagement point is clearly indicated.

Brief description of the drawings Figure 1 is a schematic illustration of a vehicle comprising a clutch by wire system according to the present invention. Figure 2 is a block diagram schematically illustrating the present invention. Figures 3a-3c are schematic illustrations of a clutch pedal in different clutch states. Figures 4a-4c illustrate visual indication signals indicating the different clutch states shown in figures 3a-3c, respectively, according to one embodiment of the present invention. Figures 5a-5c illustrate tactile indication signals indicating the different clutch states shown in figures 3a-3c, respectively, according to another embodiment of the present invention. Figures 6a-6c illustrate tactile indication signals indicating the different clutch states according to still another embodiment of the present invention. Figure 7 is a flow diagram illustrating the method according to the present invention.

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

Figure 1 is a schematic illustration of a vehicle 4 that comprises the clutch by wire (CBW) system 2 according to the present invention. The vehicle may be a cargo vehicle, a truck, a bus, a car or any vehicle provided with a clutch. in figure 2 a block diagram is shown that schematically illustrates the clutch by wire system 2 according to the present invention.

The CBW system comprises a clutch control module 6, a clutch pedal 8, and a clutch pedal position sensor unit 10. The sensor unit 10 is configured to measure the pedal position, to generate a pedal position signal 12 including pedal position data, and to apply the pedal position signal 12 to the clutch control module 6. The clutch control module is configured to determine a clutch control signal 14, including clutch control instructions, in dependence of the pedal position data and one or many clutch control parameters 18.

The clutch control module 6 is further configured to generate the clutch control signal 14 and to apply the signal 14 to a clutch 16 of the vehicle 4.

The clutch 16 is thereby controlled to be in a clutch state. The clutch state is any state of the clutch 16 from a fully engaged clutch state where full driving of the vehicle is achieved, to a fully disengaged clutch state, and all states there between, e.g. an engagement point state where the clutch is about to be engaged. The clutch pedal positions of these clutch states are very schematically illustrated in figures 3a-3c, where figure 3a shows the clutch pedal in a fully engage state position, figure 3b shows the clutch pedal in the engagement point state position, and figure 3c shows the clutch pedal in a fully disengaged state position.

According to the present invention, and with references in particular to figure 2, the CBW system 2 comprises an indication unit 20 configured to generate an indication signal 22 in dependence of the clutch control signal 14, and that the indication signal 22 includes information representing the clutch state. The indication signal 22 is a visual 24, an audible, or a tactile 28 signal, or a combination of these, to indicate the clutch state to a user of the vehicle. This is advantageous in that the user then will receive a feedback of the clutch state.

In one embodiment the indication unit 20 is configured to apply predetermined indication instructions to determine information of the indication signal such that the indication specifically indicates when the clutch 16 is in the engagement point state, such that said engagement point state is identifiable by the user of the vehicle.

Furthermore, the indication unit 20 is preferably configured to apply predetermined indication instructions to determine information of the indication signal to separate the fully engaged clutch state, the engagement point state, and the fully disengaged clutch state, from each other. The indication instructions may provide for a gradual change of the indication signal between indicated clutch states, or instead may provide for more distinct steps between the indicated states.

In an embodiment of the clutch by wire system the indication signal 22 is a visual signal 24 and that the system comprises a display unit 30 where the visual signal is presented to the user of the vehicle. The display unit 30 is illustrated in figures 4a-4c. where figure 4a illustrates the display unit 30 indicating a fully engaged clutch, cf. figure 3a, figure 4b illustrates the display unit 30 indicating that the clutch is in its engagement point state, and figure 4c illustrates the display unit 30 indicating a fully disengaged clutch. The display unit 30 is preferably in integral part of an information presentation interface of the vehicle. As an alternative, the display unit may be a separate unit.

The indication unit 20 is configured to apply predetermined indication instructions to determine information of the indication signal such that each of the fully engaged clutch state, the engagement point state, and the fully disengaged clutch state, and has a designated colour. These colours may e.g. be green, light green and yellow, respectively. Naturally, any colours may be chosen, if only the engagement point state is to be indicated, that state may be indicated by e.g. green or any other colour.

According to another embodiment the indication signal 22 is a tactile signal 28 (see figures 5a-5c and 6a-6c), which may be generated as vibrations of the clutch pedal, or as vibrations of the steering wheel. Figures 5a-5c schematically illustrates one version of this embodiment where a first vibration unit 32 is provided in relation to the clutch pedal. The first vibration unit is configured to generate the tactile signal as a vibration of the clutch pedal. In figure 6b, illustrating the engagement point state the tactile signal 28 is stronger, or having a different frequency, in comparison to the fully disengaged state illustrated in figure 6c. Figures 6a-6c schematically illustrates another version of this embodiment where a second vibration unit 34 is provided in relation to a steering wheel 36 of the vehicle, and being configured to generate the tactile signal 28 as a vibration of the steering wheel. in order to determine the clutch control signal one or many clutch control parameters 18 are taken into account. These may comprise an inclination parameter including information of the current inclination of the vehicle, and/or a weight parameter including information of the weight of the vehicle, and/or an axial pressure parameter including information of axle load pressure of one or many axles of the vehicle.

The engagement point may vary in dependence of those parameters. In one implementation the same depression of the clutch pedal always will result in that the clutch state is in the engagement point state, irrespective of the values of the clutch control parameters. In another implementation, the clutch pedal depression to reach the engagement point state may vary in dependence of those parameters.

The present invention also relates to a method in a clutch by wire (CBW) system for a vehicle. The method will now be described with references to the flow diagram illustrated in figure 7. The CBW system has been described in detail above, and comprises a clutch control module, a clutch pedal, a clutch pedal position sensor unit. For a more detailed description of the system it is referred to the above description.

Thus, the method comprises: - measuring the pedal position, - generating a pedal position signal including pedal position data, - applying the pedal position signal to said clutch control module, - determining a clutch control signal including clutch control instructions in dependence of said pedal position data and one or many clutch control parameters, - generating said clutch control signal, - applying said clutch control signal to a clutch of the vehicle, - controlling the clutch to be in a clutch state, wherein said clutch state is any state of the clutch from a fully engaged clutch state to a fully disengaged clutch state, and includes an engagement point state where the clutch is about to be engaged.

The method further comprises generating an indication signal by an indication unit in dependence of the clutch control signal. The indication signal includes information representing the clutch state, and is a visual, an audible, or a tactile signal, or a combination of these, to indicate the clutch state to a user of the vehicle.

In particular the method comprises applying predetermined indication instructions to determine information of the indication signal to specifically indicate when the clutch is in the engagement point state, such that the engagement point state is identifiable by the user of the vehicle. The predetermined indication instructions to determine information of the indication signal to separate the fully engaged clutch state, the engagement point state, and the fully disengaged clutch state, from each other.

According to one embodiment the indication instructions provide for a gradual change between indicated clutch states, or instead may provide for more distinct steps between the indicated states. in one embodiment the indication signal is a visual signal and the method comprises presenting the visual signal at a display unit. The method then comprises predetermined indication instructions to determine information of the indication signal such that each of the fully engaged clutch state, the fully disengaged clutch state, and the engagement point state has a designated colour. This embodiment is further outlined above in connection with the description of the CBW system. in another embodiment the indication signal is a tactile signal, and according to one variation the method comprises generating the tactile signal as a vibration of the clutch pedal by a first vibration unit provided in relation to the clutch pedal. According to another variation the indication signal is a tactile signal, and the method comprises generating the tactile signal as a vibration of a steering wheel of the vehicle by a second vibration unit provided in relation to the steering wheel. This embodiment is also further outlined above.

The vehicle 4 communicates internally between its units, devices, sensors, detectors etc. via a communication bus, for example a CAN-bus (Controller Area Network) which uses a message based protocol. Examples of other communication protocols that may be used are TTP (Time-Triggered Protocol), Flexray, etc. In that way signals and data described herein may be exchanged between different units, devices, sensors and/or detectors in the vehicle 4. Signals and data may instead be transferred wireiessiy between the different units, devices, sensors and/or detectors.

The present invention also comprises a computer program P (see figure 2) wherein the computer program P comprises a computer program code to cause a clutch by wire (CBW) system as disclosed above, or a computer connected to the system, to perform the method which also has been disclosed above. In addition a computer program product, is provided, comprising a computer program code stored on a computer-readable medium to perform the method being disclosed above, when the computer program code is executed by a CBW system defined above, or by a computer connected to that system.

More particularly, the CBW system may further include a processing unit and a memory unit. The processing unit may be made up of one or more Central Processing Units (CPU). The memory unit may be made up of one or more memory units. A memory unit may include a volatile and/or a non-volatile memory, such as a flash memory or Random Access Memory (RAM). The memory unit comprises the computer program P including the computer program code to cause the CBW system, or a computer connected to the system, to perform any of the method steps described above. The CBW system may be an Electronic Control Unit (ECU).

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.

Claims

1. A clutch by wire (CBW) system (2) for a vehicle (4), comprising a clutch control module (6), a clutch pedal (8), a clutch pedal position sensor unit (10) configured to measure the pedal position, to generate a pedal position signal (12) including pedal position data, and to apply the pedal position signal (12) to said clutch control module (6) that is configured to determine a clutch control signal (14) including clutch control instructions in dependence of said pedal position data and one or many clutch control parameters (18), to generate said clutch control signal (14) and to apply said clutch control signal (14) to a clutch (16) of the vehicle (4) to control the clutch (16) to be in a clutch state, wherein said clutch state is any state of the clutch (16) from a fully engaged clutch state to a fully disengaged clutch state, and includes an engagement point state where the clutch is about to be engaged, characterized in that the CBW system (2) comprises an indication unit (20) configured to generate an indication signal (22) in dependence of said clutch control signal (14), wherein said indication signal (22) includes information representing the clutch state, and is a visual (24), an audible, or a tactile (28) signal, or a combination of these, to indicate the clutch state to a user of the vehicle.

2. The clutch by wire system according to claim 1, wherein said indication unit (20) is configured to apply predetermined indication instructions to determine information of said indication signal to specifically indicate when the clutch (16) is in the engagement point state.

3. The clutch by wire system according to claim 1 or 2, wherein said indication unit (20) is configured to apply predetermined indication instructions to determine information of said indication signal to separate the fully engaged clutch state, the engagement point state, and the fully disengaged clutch state, from each other.

4. The clutch by wire system according to claim 2 or 3, wherein said indication instructions provide for a gradual change between indicated clutch states.

5. The clutch by wire system according to any of claims 1 -4, wherein said indication signal (22) is a visual signal (24) and that said system comprises a display unit (30) where the visual signal is presented to the user of the vehicle.

6. The clutch by wire system according to claim 5, wherein said indication unit (20) is configured to apply predetermined indication instructions to determine information of said indication signal such that each of the fully engaged clutch state, the fully disengaged clutch state, and the engagement point state has a designated colour.

7. The clutch by wire system according to any of claims 1 -4, wherein said indication signal (22) is a tactile signal (28), and that said system comprises a first vibration unit (32) provided in relation to the clutch pedal, and being configured to generate the tactile signal as a vibration of the clutch pedal.

8. The clutch by wire system according to any of claims 1 -4, wherein said indication signal (22) is a tactile signal (28), and that said system comprises a second vibration unit (34) provided in relation to a steering wheel (36) of the vehicle, and being configured to generate the tactile signal as a vibration of the steering wheel.

9. A method in a clutch by wire (CBW) system (2) for a vehicle (4), comprising a clutch control module (6), a clutch pedal (8), a clutch pedal position sensor unit (10), the method comprises: - measuring the pedal position, - generating a pedal position signal (12) including pedal position data, - applying the pedal position signal (12) to said clutch control module (6), - determining a clutch control signal (14) including clutch control instructions in dependence of said pedal position data and one or many clutch control parameters (18), - generating said clutch control signal (14), - applying said clutch control signal (14) to a clutch (16) of the vehicle (4), - controlling the clutch (16) to be in a clutch state, wherein said clutch state is any state of the clutch (16) from a fully engaged clutch state to a fully disengaged clutch state, and includes an engagement point state where the clutch is about to be engaged, c h a r a cf e r i z e d in that method further comprises: - generating an indication signal (22) by an indication unit (20) in dependence of said clutch control signal (14), wherein said indication signal (22) includes information representing the clutch state, and is a visual (24), an audible, or a tactile (28) signal, or a combination of these, to indicate the clutch state to a user of the vehicle.

10. The method according to claim 9, comprising applying predetermined indication instructions to determine information of said indication signal to specifically indicate when the clutch (16) is in the engagement point state.

11. The method according to claim 9 or 10, comprising applying predetermined indication instructions to determine information of said indication signal to separate the fully engaged clutch state, the engagement point state, and the fully disengaged clutch state, from each other.

12. The method according to claim 10 or 11, wherein said indication instructions provide for a gradual change between indicated clutch states.

13. The method according to any of claims 9-11, wherein said indication signal (22) is a visual signal (24) and the method comprises presenting the visual signal at a display unit (30).

14. The method according to claim 13, comprising applying predetermined indication instructions to determine information of said indication signal such that each of the fully engaged clutch state, the fully disengaged clutch state, and the engagement point state has a designated colour.

15. The method according to any of claims 9-12, wherein said indication signal (22) is a tactile signal (28), and the method comprises generating the tactile signal as a vibration of the clutch pedal by a first vibration unit (32) provided in relation to the clutch pedal.

16. The method according to any of claims 9-12, wherein said indication signal (22) is a tactile signal (28), and the method comprises generating the tactile signal as a vibration of steering wheel (36) of the vehicle by a second vibration unit (34) provided in relation to the steering wheel (36).

17. A vehicle comprising a clutch by wire system according to any of claims 1-8.

18. A computer program P, wherein said computer program P comprises a computer program code to cause a clutch by wire (CBW) system (2) according to any of claims 1-8, or a computer connected to said CBW system (2), to perform the method according to any of claims 9-16.

19. 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 9-16, when said computer program code is executed by a clutch by wire system (2) according to any of claims 1-8, or by a computer connected to said CBW system (2).