METHOD FOR CONTROLLING THE ENGAGEMENT AND/OR DISENGAGEMENT OF A PARKING LOCK OF A TRANSMISSION OF A VEHICLE, IN PARTICULAR OF A MOTOR VEHICLE

Abstract

A method for controlling the engagement and/or disengagement of a parking lock of a transmission of a vehicle, in particular of a motor vehicle

Claims

1. A method for controlling an engagement and/or disengagement of a parking lock of a transmission of a vehicle, in particular of a motor vehicle, wherein the vehicle comprises the parking lock, a parking brake and a control unit, the method comprising: actively engaging or disengaging the parking lock in and/or on the transmission, in particular in an automatic transmission; securing, for the ascertainment of a driver demand, the vehicle against rolling away and/or against onward travel, wherein the vehicle has at least one device for activating the parking lock, in particular a parking lock button and/or a particular positioning capability for a selector lever, and at least one device for activating the parking brake, in particular at least one parking brake button; controlling the active engagement and disengagement of the parking lock in or on the transmission via the control unit; and transmitting at least one present determined first driving parameter to the control unit and/or is ascertained by the control unit, but in particular the control unit ascertains present values of multiple determined driving parameters, wherein, as a determined first driving parameter, at least the present vehicle speed of the vehicle is ascertained and/or calculated when the driver has actuated the device for activating the parking lock, wherein, the parking lock is actively engaged in or on the transmission only when the vehicle is at a standstill and/or the present driving speed is substantially zero, wherein, if the vehicle has not yet reached its standstill and the present vehicle speed exceeds a determined vehicle speed threshold value, the active engagement of the parking lock in or on the transmission is prevented, and/or, if the vehicle has not yet reached its standstill and the present vehicle speed falls below a determined vehicle speed threshold value, then the vehicle initially continues to be braked by the then automatically activated parking brake until the standstill is reached and/or until the driving speed of the vehicle has reached substantially zero, wherein, as a second driving parameter, the present gradient of the roadway and/or the longitudinal inclination of the vehicle is ascertained and/or calculated, and wherein, on the basis of the ascertained gradient value and/or the ascertained longitudinal inclination value of the vehicle, it is decided and/or checked whether a hydraulic brake system of the vehicle is activated.

2. The method according to claim 1, wherein, in the event that the vehicle speed is substantially zero and/or the vehicle is at a standstill and the amount of the ascertained gradient value and/or ascertained inclination value falls below the amount of a determined first inclination threshold value or is equal to this amount, then the hydraulic brake system is automatically activated, in particular for a maximum of 2 seconds.

3. The method according to claim 2, wherein, after the hydraulic brake system is activated, the parking lock is automatically actively engaged in or on the transmission.

4. The method according to claim 3, wherein, after the parking lock is actively engaged, the hydraulic brake system is automatically deactivated again, specifically no parking brake is then automatically activated for further securing the vehicle against rolling away, and/or, a possibly already activated parking brake is automatically deactivated again.

5. The method according to claim 1, wherein, in the event that the vehicle speed is substantially zero and/or the vehicle is at a standstill and the amount of the ascertained gradient value and/or ascertained inclination value exceeds the amount of a determined first inclination threshold value, then the parking brake is automatically activated.

6. A method for controlling an engagement and/or disengagement of a parking lock of a transmission of a vehicle, in particular of a motor vehicle, wherein the vehicle comprises the parking lock, a parking brake, and a control unit, wherein the parking lock is adapted to be actively engaged or disengaged in and/or on the transmission, in particular in an automatic transmission, wherein, for the ascertainment of a driver demand, to secure the vehicle against rolling away and/or against onward travel, the vehicle has at least one device for activating the parking lock, in particular a parking lock button and/or a particular positioning capability for a selector lever, and at least one device for activating the parking brake, in particular at least one parking brake button (EPB button), wherein the control of the active engagement and disengagement of the parking lock in or on the transmission is controlled by the control unit, the method comprising: transmitting or ascertaining at least one present determined first driving parameter to or by the control unit, in particular the control unit ascertains present values of multiple determined driving parameters; ascertaining/calculating, as a determined first driving parameter, at least the present vehicle speed of the vehicle when the driver has actuated the device for activating the parking lock; actively engaging the parking lock in or on the transmission only when the vehicle is at a standstill and/or the present driving speed is substantially zero; and preventing, if the vehicle has not yet reached its standstill and the present vehicle speed exceeds a determined vehicle speed threshold value, the active engagement of the parking lock in or on the transmission is prevented and/or if the vehicle has not yet reached its standstill and the present vehicle speed falls below a determined vehicle speed threshold value, then the vehicle initially continues to be braked by the then automatically activated parking brake until the standstill is reached and/or until the driving speed of the vehicle has reached substantially zero; and ascertaining/calculating, as a second driving parameter, a present gradient of the roadway and/or a longitudinal inclination of the vehicle, and based on the ascertained/calculated gradient value and/or the ascertained/calculated longitudinal inclination value of the vehicle, it is decided and/or checked whether an already activated parking brake should be deactivated by the driver.

7. The method according to claim 6, wherein, in the event that the parking brake is already automatically activated and/or the vehicle is at a standstill and the parking lock is actively engaged and the amount of the ascertained gradient and/or ascertained inclination value falls below the amount of a determined second inclination threshold value or is equal to this amount, it is permitted and/or possible for the driver to release and/or deactivate the parking brake at any time.

8. The method according to claim 6, wherein, in the event that the parking brake is already automatically activated and/or the vehicle is at a standstill and the parking lock is actively engaged and the amount of the ascertained gradient value and/or ascertained inclination value exceeds the amount of a determined second inclination threshold value, the driver is not automatically permitted to, and/or is automatically prevented, from releasing and/or deactivating the parking brake at least as long as the parking lock is actively engaged.

9. The method according to claim 8, wherein the parking brake is deactivated by the driver only when the parking lock is actively disengaged in or on the transmission.

10. The method according to claim 7, wherein, when the parking brake is deactivated by the driver, the parking lock is also automatically actively disengaged, in particular shortly before but at least at the same time.

11. The method according to claim 1, wherein an actively engaged parking lock is automatically disengaged when the driver operates the accelerator when a gear is frictionally, actively engaged in the transmission.

12. The method according to claim 1, wherein, for continuing to brake the vehicle until the standstill of the vehicle is reached, the hydraulic brake system is activated.

13. The method according to claim 1, wherein the corresponding determined vehicle speed threshold value is 3 km/h.

14. The method according to claim 1, wherein the determined first gradient value and/or inclination threshold value corresponds to a 5% road gradient or a corresponding road decline and/or the determined second gradient value and/or inclination threshold value corresponds to a 15% road gradient or a corresponding road decline.

15. The method according to claim 1, wherein, in the event of a deactivation of the parking lock, in particular with a corresponding activation of the parking lock button, with an active disengagement of the parking lock, an activated parking brake is also automatically deactivated at the same time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0034] FIG. 1 is a schematic representation for carrying out the inventive method for a vehicle, in particular for a motor vehicle, and

[0035] FIG. 2 is a schematic representation of a circuit diagram for carrying out the inventive method according to a first example, represented in FIG. 2 by path I, or according to a second example, represented in FIG. 2 on the right by path II, wherein these first and second examples can be carried out in combination with each other (complete view of FIG. 2, i.e., path I and path II in combination).

DETAILED DESCRIPTION

[0036] FIG. 1 initially shows the essential components for the realization of the inventive method for controlling the engagement and/or disengagement of a parking lock 1 of a transmission 2 of a vehicle, in particular a motor vehicle 3a, which is only indicated by a dashed line 3.

[0037] The vehicle 3, i.e., the motor vehicle 3a, has a parking lock 1 and a transmission 2. In particular, the parking lock 1 is at least partially arranged within the transmission 2. Furthermore, the vehicle 3, i.e., the motor vehicle 3a, has a parking brake 4 and a control unit 5. The parking lock 1 can be actively engaged or disengaged by means of at least one activatable parking lock actuator, in the transmission 2, in this case in particular in an automatic transmission 2a, in particular when the transmission 2 is in the neutral position “N”. In this case, the parking lock 1 can be actively engaged in and/or on the transmission 2, this means, in particular, that the parking lock 1 and/or the necessary mechanical components are at least partially arranged accordingly in and/or on the transmission 2 or in the area of the transmission 2.

[0038] For the ascertainment of a driver demand, namely the driver demand that the vehicle 3 be secured against unintentionally rolling away and/or against unintentional onward travel, the vehicle 3 has at least one device 6 for activating the parking lock 1, in particular a parking lock button 6a, and/or a particular positioning capability for a selector lever (position “P”), and at least one device 7 for activating the parking brake 4, in particular at least one parking brake button 7a (EPB button). The device 6, in particular the parking lock button 6a and/or the device 7, in particular the parking brake button 7a, can be manually actuated by the driver, in particular pressed, in particular inside the passenger compartment.

[0039] By means of the control unit 5, the control of the active engagement and disengagement of the parking lock 1 in the transmission 2 is controlled, in particular automatically controlled. In this case, in particular, present values of multiple driving parameters are transmitted to the control unit 5 and/or present values of multiple driving parameters (v, s) are ascertained by the control unit 5. At least one present determined driving parameter (v) is transmitted to the control unit and/or ascertained by the control unit 5, wherein the present vehicle speed v of the vehicle is ascertained as a determined first driving parameter. The vehicle speed v is ascertained by the control unit 5, in particular permanently/continuously, but at least then when the driver desires to secure the vehicle 3 against rolling away and/or against onward travel, and at least then, the vehicle speed v is ascertained when the driver has actuated the device 6, in particular the parking lock button 6a, in order to activate the parking lock 1, i.e., when said driver desires to engage the parking lock 1 in the transmission 2.

[0040] However, the parking lock 1 is only actively engaged in and/or on the transmission 2 when the vehicle 3 is at a standstill and/or the present vehicle speed v is substantially zero. This applies substantially to all examples of the method; this may be pointed out. The term “is substantially zero” means that even very low vehicle speeds, such as less than or equal to 0.05 km/h, and/or corresponding measurement inaccuracies in this area, should be or are still included in the term “is substantially zero”.

[0041] In the following, a first and then a second example of the inventive method is described. Here, the first example is substantially represented by the path I in FIG. 2 on the left, and the second example by the path II in FIG. 2 on the right, wherein both examples can be combined with each other accordingly to form a third example, as mentioned above.

[0042] However, the examples or the respective inventive methods substantially also have in common that—as FIG. 2 shows—the driver first actuates the device 6, in particular the parking lock button 6a, at the beginning of the method, represented here by the reference sign “10”, because said driver desires to secure the vehicle 3 against rolling away and/or onward travel, in particular because said driver desires to actively engage the parking lock 1 in the transmission 2 (shown in FIG. 2 at the top).

[0043] In a first method step 11, the present vehicle speed v is ascertained and/or the present vehicle speed v is checked. However, the parking lock 1 is only actively engaged in and/or on the transmission 2, which in turn is substantially the same for all methods, when the vehicle 3 is at a standstill and/or the present vehicle speed v is substantially zero. If the vehicle 3 has not yet reached its standstill or if the present vehicle speed v exceeds a determined vehicle speed threshold value, if in particular the vehicle speed is greater than 3 km/h, the active engagement of the parking lock 1 in and/or on the transmission 2 is automatically prevented by means of the control unit 5, although the driver has already actuated the device 6, in particular the parking lock button 6a. This is shown in FIG. 2 by method step 12 there. There is no active engagement of the parking lock 1. If the vehicle 3 has not yet reached its standstill and the present vehicle speed v falls below a determined vehicle speed threshold value, in particular 3 km/h, then the vehicle 3 can continue to be braked by means of the then automatically activated parking brake 4 until said vehicle reaches its standstill and/or until the vehicle speed has reached substantially zero (the latter is represented in particular at the beginning of path II in FIG. 2, center, by method step 13. In particular, the vehicle 3 continues to be braked by the then automatically activated parking brake 4 when the vehicle speed v is less than or equal to 3 km/h). Or the latter, again expressed differently, only when the vehicle speed v of the vehicle 3 reaches or falls below the determined vehicle speed threshold value, in particular reaches or falls below 3 km/h, can the vehicle 3 be continued to be braked to a standstill and/or until the vehicle speed v is substantially zero by means of an automatically activated parking brake 4, represented by method step 13.

[0044] In the following, the respective examples of the inventive method will now be described in more detail:

[0045] The disadvantages mentioned above are now initially avoided in the first example of the method in that, as a second driving parameter, the present gradient s of the roadway and/or the longitudinal inclination of the vehicle 3 is ascertained and/or calculated, and that on the basis of the determined, in particular present gradient value S.sub.x and/or the determined longitudinal inclination value of the vehicle 3, it is decided and/or checked whether a hydraulic brake system 8 of the vehicle 3 is activated. The preferred first example of the method is shown in FIG. 2, on the left, specifically shown here in path I. In the event that the vehicle speed v is substantially zero and/or the vehicle 3 is at a standstill and the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x falls below or is equal to the amount of a determined first inclination threshold value SG.sub.1, the hydraulic brake system 8 is automatically activated, in particular for a maximum of 2 seconds. As a result, when at a standstill, the vehicle 3 is then secured or “firmly braked” against rolling away by the hydraulic brake system 8. After this securing or after the activation of the hydraulic brake system 8, the parking lock 1 is then automatically actively engaged in and/or on the transmission 2. After the parking lock 1 is actively engaged, the hydraulic brake system 8 is automatically deactivated again, in particular after the 2 seconds mentioned above. In particular, no parking brake 4 is automatically activated to further secure the vehicle 3 against rolling away, because the vehicle 3 is in particular secured against rolling away by the actively engaged parking lock 1. The aforementioned method steps of the first example are schematically represented in particular by path I in FIG. 2, on the left. In method step 14, it is therefore checked whether the ascertained gradient value and/or ascertained inclination value S.sub.x is less than or equal to the amount of the determined first inclination threshold value SG.sub.1. In the event that this condition is fulfilled, the hydraulic brake system 8 is then automatically activated in method step 15. Thereafter, the parking lock 1 is then automatically actively engaged in or on the transmission 2 in method step 16. After the parking lock 1 is actively engaged, the hydraulic brake system 8 is automatically deactivated again in method step 17. The hydraulic brake system 8 is therefore activated in particular when the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x is less than or equal to the amount of the determined first inclination threshold value SG.sub.1.

[0046] Before reference is made to the second example of the invention, or before this second example is described in more detail, it may already be pointed out here that in the event that the vehicle speed v is substantially zero and/or the vehicle 3 is at a standstill and the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x exceeds the amount of the determined first inclination threshold value SG.sub.1, then the parking brake 4 is automatically activated, i.e., in particular, the hydraulic brake system 8 is not automatically activated, and the branching from path I to path II shown in FIG. 2 takes place. In other words, when the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x is greater than the amount of the determined first inclination threshold value SG.sub.1, the hydraulic brake system 8 is not activated and the parking brake 4 can be activated. Method step 13 can then be carried out. In particular, this branching also shows here, at least partially, the combination of the first and second examples.

[0047] In the following, the second example of the inventive method will now be described in more detail:

[0048] In the second example of the method according to the invention, the device 6 or the parking lock button 6a is initially also actuated by the driver (cf. step 10), wherein the parking lock 1 is then not yet actively engaged in the transmission 2. First, the vehicle speed v is ascertained (cf. method step 11). If the vehicle speed v exceeds a determined vehicle speed threshold value, in particular greater than 3 km/h, the parking lock 1 is automatically prevented from actively engaging in the transmission 2 (cf. method step 12). If the vehicle speed v falls below the determined vehicle speed threshold value, in particular less than 3 km/h, but the vehicle 3 is not yet at a standstill, then the parking brake 4 is automatically activated in order to continue to brake the vehicle 3. This is shown in particular in path II of FIG. 2 (cf. method step 13). When the vehicle 3 reaches a standstill or when the vehicle speed v is substantially zero, the parking lock 1 is automatically actively engaged in the transmission 2. This is represented by method step 18.

[0049] The disadvantages mentioned above are avoided by the second example of the method, first by the fact that, as a second driving parameter, the present gradient s of the roadway and/or the longitudinal inclination of the vehicle 3 is ascertained and/or calculated and that on the basis of the ascertained gradient value S.sub.x and/or the ascertained longitudinal inclination value of the vehicle 3 it is decided and/or checked whether an already activated parking brake 4 can be deactivated again by the driver. This has special advantages, in particular in the case of steeper gradient and/or a greater road decline, which will be explained more closely below.

[0050] In the event that the parking brake 4 is already activated, in particular automatically, and/or the vehicle 3 is at a standstill and the parking lock 1 is actively engaged in the transmission 2 and the amount of the determined gradient value and/or ascertained inclination value S.sub.x falls below or is equal to the amount of a determined second inclination threshold value SG.sub.2, it is permitted and/or possible for the driver to release and/or deactivate the parking brake 4, in particular by actuating the device 7, in particular the parking brake button 7a, at any time. This is shown graphically in FIG. 2, at the bottom right, where the amount of the ascertained present gradient value and/or ascertained inclination value S.sub.x then just happens to not be greater than the second inclination threshold value SG.sub.2, i.e., the query shown here is denied, so that then the driver is permitted to release the parking brake 4 by means of the control unit 5 when said driver actuates the device 7 accordingly, in particular the parking brake button 7a. In method step 19, therefore, it is checked whether the ascertained gradient value and/or ascertained inclination value S.sub.x is greater than the second inclination threshold value SG.sub.2. If this check/query is denied, then method step 20 is carried out and the driver is permitted to release the parking brake 4 by means of the control unit 5, in particular when said driver actuates the device 7 or the parking brake button 7a accordingly, in particular the parking brake 4 can then be deactivated accordingly. Again, in other words, when the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x is less than or equal to the amount of the determined second inclination threshold value SG.sub.2, then it is permitted and/or possible for the driver to release or deactivate the parking brake 4, in particular by actuating the parking brake button 7a, at any time by means of the control unit 5.

[0051] In the event that the parking brake 4 is, in particular, automatically activated and/or the vehicle 3 is at a standstill and the parking lock 1 is actively engaged and the amount of the ascertained gradient value and/or ascertained inclination value S.sub.x exceeds the amount of a determined second inclination threshold value SG.sub.2, the driver is not permitted and/or is automatically prevented from releasing and/or deactivating the parking brake 4 at least as long as the parking lock 1 is actively engaged in the transmission 2. This is shown graphically in FIG. 2 in path II at the bottom (center) or is represented by the method step 21.

[0052] As a result, if the gradient of the road or the longitudinal inclination of the vehicle 3 is correspondingly steep, then the driver cannot deactivate the parking brake 4, in particular not manually, until the parking lock 1 is also actively disengaged in the transmission 2. This prevents a rolling into an actively engaged parking lock 1.

[0053] In principle, it is also conceivable that the parking brake 4 can only be deactivated by the driver when the parking lock 1 is actively disengaged in and/or on the transmission 2. It is conceivable that when the parking brake 4 is deactivated by the driver, the parking lock 1 is also automatically actively disengaged in the transmission 2, in particular shortly before or at least at the same time, in particular to prevent a rolling into an actively engaged parking lock 1. For this purpose, a common button element 9 could then be provided.

[0054] The steps shown in path I and path II can be implemented together. This is shown, in particular, by the branch between path I and path II shown in FIG. 2 on the top left, namely that it is possible to “jump” from path I to path II when the amount of the ascertained gradient value S.sub.x is greater than the first determined inclination threshold value SG.sub.1.

[0055] In general, and this relates to all three examples of the inventive method, an actively engaged parking lock 1 can be automatically disengaged when the driver operates the accelerator when a gear is frictionally, actively engaged in the transmission 2. It is also conceivable that for continuing to brake the vehicle 3 until the vehicle 3 standstill is reached, in particular when the vehicle speed v is lower than the determined vehicle speed threshold value, in particular less than 3 km/h, the hydraulic brake system 8 is activated for this purpose.

[0056] As already mentioned above, the determined vehicle speed threshold value is in particular 3 km/h. Other values are conceivable, which are in particular between the values 2 to 5 km/h.

[0057] Preferably, the determined first gradient value and/or inclination threshold value SG.sub.1 corresponds to a 5% road gradient (or a corresponding road decline) and/or the determined second gradient value and/or inclination threshold value SG.sub.2 corresponds to a 15% road gradient (or a corresponding road decline).

[0058] It is also conceivable that by means of the control unit 5, an already activated parking brake 4 is also automatically deactivated at the same time when the parking lock 1 is deactivated by the driver, in particular when the parking lock button 6a is actuated, i.e., in particular with an active disengagement of the parking lock 1. This may also be pointed out.

[0059] As a result, by means of the first and second example of the invention, but in particular also by means of the third example of the invention, which combines the first and second example, corresponding advantages are achieved, and corresponding disadvantages known from the prior art are avoided.

[0060] It is conceivable, it may be pointed out, that the devices 6 and 7, the buttons 6a and 7a, are designed as “software buttons” and/or even that a corresponding voice control by the driver is implemented.

[0061] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.