Automatic transmission control system and method for controlling a transmission actuator

Abstract

Transmission control system that includes: a transmission (320) designed to be arranged on a motor vehicle drive (325a, 325b), wherein the transmission (320) has a transmission actuating device (100) designed to cause at least one gear change operation with respect to the transmission (320), wherein the transmission actuating device (100) comprises: a cylinder body (105) having a first inlet (110) and a second inlet (120), and a switching piston (130) movable between a first end position (150) and a second end position (160) within the cylinder body (105) in response to a first fluid flow (F1) supplied via the first inlet (110) and / or to a second fluid flow (F2) supplied via the second inlet (120); and a transmission control unit (330) configured to actuate the transmission actuating device (100) in response to at least one transmission control command, characterized in that the transmission control unit (330) is configured to actuate the transmission actuating device (100) such that: when the piston (130) is in the first end position (150) and the at least one transmission control command indicates that the piston (130) is to be moved to the second end position (160), the first fluid flow (F1) is caused to be supplied through the first inlet (110) before the second fluid flow (F2) is caused to be supplied through the second inlet (120), and then when the piston (130) is in the second end position (160) and the at least one transmission control command indicates that the piston (130) is to be moved to the first end position (150), the second fluid flow (F2) is caused to be supplied through the second inlet (120) before the first fluid flow (F1) is caused to be supplied through the first inlet (110).

Description

BACKGROUND OF THE INVENTION AND PRIOR ARTThe present invention relates generally to transmission shift devices. The invention relates in particular to a transmission control system according to the preamble of claim 1 and a motor vehicle according to claim 8, the invention also relates to a method for controlling / regulating a transmission actuation device according to the preamble of claim 9, a computer program according to claim 16 and a computer-readable medium according to claim 17.When the transmission shifting device is operated in automatic transmissions, automated manual transmissions, and other types of automatically controlled transmissions, uncomfortable impacts and noises may occur. Although this does not normally pose a risk of degrading the transmission system of the vehicle, the driver and / or passengers in the vehicle may feel the shocks and noises annoying. Therefore, various solutions have been developed to address this problem.US 5 669 265 A describes an arrangement for a gear change operation by means of a construction including a two-stage cylinder. An inner cylinder is movable here with an outer cylinder. As a result, both a first piston movement can take place relatively quickly and an end phase movement of the piston can take place relatively slowly. As a result, for example, a gear change with respect to a synchronous gear change gear can be performed both smoothly and efficiently. GB 983 271 A discloses a similar solution according to which a uniform gear change is implemented by using a two-stage cylinder and piston arrangement.WO 90 / 03 523 A1 describes an alternative solution for damping a gear change device at its end position. Here, a back pressure chamber is formed as an annular groove in the piston front side opposite to the cylinder end. The chamber contains compressed air which is discharged through a narrow passage when the piston reaches the end, thereby reducing the impact of the piston. The back pressure chamber is disposed radially inward with respect to the cylinder wall so that the piston rings around the circumference of the piston are unaffected by the high back pressure.DE 196 80 781 B4 describes a control for a torque transmission system for a motor vehicle with an automated clutch, which comprises an actuating unit for actuating a clutch process and a shifting and selecting process for a gear change.Nevertheless, the previous constructions for piston damping are all mechanically complex. Therefore, the solutions are comparatively error-prone and / or expensive to implement.SUMMARY OF THE INVENTIONThe object of the present invention is therefore to provide a solution which provides a reliable, cost-effective and uncomplicated transmission control means having a smooth and quiet behavior.According to one aspect of the invention, the object is achieved by the transmission control system described in the opening paragraph, wherein the transmission control unit is configured to actuate the transmission actuating device such that, when the piston is in the first end position and the at least one transmission control command indicates that the piston is to be moved to the second end position, the first fluid flow is caused to be supplied through the first inlet before the second fluid flow is caused to be supplied through the second inlet. Similarly, the control unit is configured to operate the transmission actuator such that when the piston is in the second end position and the at least one transmission control command indicates that the piston is to be moved to the first end position, the second fluid flow is caused to be supplied through the second inlet before the first fluid flow is caused to be supplied through the first inlet.A decisive advantage of this system is that it allows a very uncomplicated cylinder and piston construction for operating the transmission shifting device. Since the proposed damper reduces the mechanical load on the cylinder body, the transmission actuator can also be made of a material having a relatively small thickness. Moreover, already existing transmission control systems can easily be adapted to implement the proposed system.According to embodiments of this aspect of the invention, the transmission control unit is configured to operate the transmission operating device such that (i) the supply of the first fluid flow is discontinued at the latest when the supply of the second fluid flow is initiated (possibly no fluid flow at all is supplied to the cylinder body during a period before the initiation of the supply of the second fluid flow), or (ii) the supply of the second fluid flow is initiated before the supply of the first fluid flow is discontinued.Depending on the implementation and desired relationship between velocity and attenuation, one of these alternatives may be advantageous. Generally, the damping effect is enhanced by decreasing the interval between the first and second fluid flows, and vice versa. The actual damping effect is indeed determined by the relationship between the total amounts of fluid delivered through the first and second inlets, respectively. As a result, the damping effect can also be adjusted by controlling the fluid flow magnitudes (fluid flow magnitudes).According to other embodiments of this aspect of the invention, the transmission control unit is thus arranged to operate the transmission actuator such that (a) the first and second fluid streams have substantially identical steady-state magnitudes (b) the first fluid stream has a steady-state magnitude greater than a steady-state magnitude of the second fluid stream, or (c) the second fluid stream has a steady-state magnitude greater than a steady-state magnitude of the first fluid stream.According to another aspect of the invention, the object is achieved by the motor vehicle described at the beginning, which comprises the system proposed above.According to a further aspect of the invention, the object is achieved by the method described in the introduction, wherein the method comprises triggering a supply of the first fluid flow through the first inlet before the supply of the second fluid flow through the second inlet is triggered when the piston is in the first end position and is to be moved to the second end position.Naturally, depending on what is defined as the first respective dependent end position, the method also comprises triggering the supply of the second fluid flow through the second inlet before the supply of the first fluid flow through the first inlet is triggered when the piston is in the second end position and is to be moved to the first end position.Starting from the foregoing discussion with respect to the proposed vehicle arrangement, the advantages of this method as well as the preferred embodiments thereof will be apparent.According to a further aspect of the invention, the object is achieved by a computer program which can be loaded directly into the internal memory of a computer, which comprises software for controlling the above-proposed method when the program runs on a computer.According to a further aspect of the invention, the object is achieved by a computer-readable medium having stored thereon a program, the program causing a computer to control the above-proposed methods.Brief Description of the DrawingsThe present invention will now be explained in more detail by way of embodiments disclosed as examples and with reference to the accompanying drawings. FIGS. 1a-d illustrate the basic operating principle of a transmission operating device according to an embodiment of the invention; FIGS. 2 a- c show graphs illustrating further embodiments of the operating principle of the device in FIGS. 1 a- d; FIG. 3 schematically illustrates a motor vehicle including a transmission control system according to an embodiment of the invention; and FIG. 4 shows a flow diagram which represents the basic method according to the invention.DESCRIPTION OF THE EMBODIMENTS OF THE INVENTIONInitially, reference is made to FIG. 1 a, which shows a transmission actuation device 100 according to an embodiment of the invention. The transmission operating device 100 is designed to cause at least one gear shift operation with respect to a transmission, i.e. for example for changing gears (up or down), or for changing between a high and a low speed range. FIGS. 1 b- d show later stages of an actuation process according to an embodiment of the invention initiated in FIG. 1 a.The apparatus 100 includes a cylinder body 105 having a first inlet 110 and a second inlet 120 for receiving a first fluid stream F1 and a second fluid stream F2, respectively. The fluid streams F1 and F2 can be realized by compressed air (as well as by other gases) or by a hydraulic liquid. FIGS. 2 a- c illustrate the fluid flows F 1 and F 2 as functions over time according to various embodiments of the invention.Returning now to FIG. 1 a, a switching piston 130 is movable between a first end position 150 and a second end position 160 within the cylinder body 105. The piston 130 is moved towards the first end position 150 as the result of the first fluid flow F 1 and towards the second end position 160 as the result of the second fluid flow F 2. A piston rod 140 is connected to the piston 130, and preferably an actuator 145 is mounted on the distal end of the piston rod 140. The member 145 is again adapted to influence a first transmission function when it is at a first position A corresponding to the piston 130 located in the first end position 150 and a second transmission function when it is at a second position B corresponding to the piston 130 located in a second end position 160. Thus, FIG. 1 ashows a situation in which the first transmission function is activated. Now, at time t=0, we assume that the transmission actuation device 100 is to trigger the second transmission function. According to the invention, the first fluid flow F 1 is firstly conveyed through the first inlet 110, with the result that the first region of the cylinder body 105 to which the piston 130 is to be moved is placed under preliminary pressure. This leads to the desired damping effect with respect to the piston movement.Then, at a somewhat later time t=t 1 the second fluid stream F 2 is conveyed through the second inlet 120. This situation is shown in Fig. 1b. At the time t=t 1 the first fluid flow F 1 can either be broken off, as shown in FIG. 2 a, or it can continue, as shown in FIG. 2 c. As a further alternative, the first fluid flow F 1 may already have been broken off before t=t 1. This embodiment of the invention is shown in Fig. 2b.After t=t 1, as the second fluid flow F2 continues to be delivered into the cylinder body 105, the shift piston 130, the piston rod 140, and the triggering member 145 move in a direction SD to the second end position 160 and the second position B, respectively. FIG. 1c shows a phase at a somewhat later time t=t 2 during this movement. An opposite fluid flow out of the first inlet 110 is denoted here by F 3. Finally, at a time t=t 3, positions 160 and B have been reached and the piston 130 stops. This phase is shown in Figure 1d. The fluid flows can be interrupted.Returning now to Figure 2a, we see a diagram with the fluid flows discussed above as functions over time. The vertical axis corresponds to a flow magnitude f (flow magnitude) and the horizontal axis shows the time t. The first fluid flow F 1 / F 3 is shown here by means of a dashed line, while the second fluid flow F 2 is shown by means of a solid line. As can be seen in Figure 2a, the first fluid flow F1 is interrupted around t = t 1 i.e. when the supply of the second fluid flow F2 is triggered. Thus, the opposing flow F3from the first inlet 110 is likewise initiated around t=t 1. Provided that the first and second inlets 110 and 120 each have the same, or at least comparable, characteristics (e.g., in terms of flow resistance), F2≈F3. In this embodiment of the invention, the first fluid stream F 1 has a steady-state magnitude f 1 (steady-state magnitude) which is greater than a steady-state magnitude f 2 of the second fluid stream F 2. In a positive flow direction into the cylinder body 105, the fluid flow F3 has a stationary magnitude -f3 which has approximately the same absolute magnitude as the stationary magnitude f2 of the second fluid flow F2.FIG. 2 bshows a diagram of an embodiment of the invention, wherein the actuation process includes a period during which no fluid flow is supplied to the cylinder body 105 before the supply of the second fluid flow F 2 is triggered. At the time t=t 11( wherein t 1 >t 11 >0), the first fluid flow is namely already interrupted. Thus, during t=t 11 to t=t 1 the cylinder body 105 receives no fluid flow via the inlets 110 or 120. Instead, a small amount of fluid flows out of the first inlet 110 during this period in the form of a fluid flow F 3.Then, at a time of t=t 1, the actuation process proceeds analogously to the process described above with reference to FIG. 2 a. Here, however, the first and second fluid streams F1 and F2 have substantially identical steady-state magnitudes (f1 and f2, respectively.FIG. 2 cshows a diagram of an embodiment of the invention, wherein, unlike the above-described embodiments, the actuation process includes a period during which the first and second fluid flows F 1 and F 2 overlap at time t. Consequently, the supply of the second fluid stream F 2 is initiated before the supply of the first fluid stream F 1 is interrupted. Specifically, in this example, the first fluid flow continues until t=t 21( where t 21 > t 1). Thus, the cylinder body 105 "receives" fluid flows through both inlets 110 and 120 during a period t=t 1 to t=t 21. Of course, the total fluid flow with respect to the cylinder body 105 must always be 0, provided that the cylinder body does not have any fluid ports other than these inlets 110 and 120. Thus, the first inlet 110 will discharge an outgoing flow (i.e., F3) at time t 1< t<t 21 when, for example, f2>f1 as shown in FIG. 2c. Starting from the time t=t 21 and furthermore the actuation process proceeds analogously to the process described above with reference to FIG. 2 a. Nevertheless, in the embodiment shown in Figure 2c, the second fluid stream F2 has a stationary magnitude f2 which is greater than a stationary magnitude f1 of the first fluid stream F1.As mentioned above, according to the invention, any combination of relationships between the stationary magnitude f1and f2with respect to the triggering time of the second fluid stream F2relative to the breaking off of the first fluid stream F1is conceivable, as described above. These are design parameters that are selected on the basis of the respective implementation requirements.FIG. 3 schematically illustrates a motor vehicle 100 that includes a transmission control system according to an embodiment of the invention. This system includes a transmission 320 and a transmission control unit 330.The transmission 320, in turn, is mounted to a propulsion of the vehicle 300. Typically, this means that the transmission 320 has a mechanical connection 325 ato a power source, for example a motor 310, and a further mechanical connection 325 bto a wheel drive axle 340, so that a driving torque can be transmitted from the power source 310 to the axle 340 via the transmission 320. The transmission 320 also has a transmission actuation device 100 which is designed to cause at least one gear shift operation with respect to the transmission 320. The transmission actuation device 100 in turn can be constructed as described above with reference to FIGS. 1 a- d.The transmission control unit 330 is configured to operate the transmission operating device 100 in view of at least one transmission control command (not shown in FIG. 3 ). This command may be either manually initiated, for example, when the transmission 320 is of a manual type, or may be automatically generated, for example, when the transmission 320 is of an automatic type. The transmission control unit 330 is further configured to actuate the transmission actuation device 100 according to the actuation process described above with reference to FIGS. 1 a- dand 2 a- d. Thus, the transmission control unit 330 causes the first fluid flow F 1 to be supplied through the first inlet 110 before causing the second fluid flow F 2 to be supplied through the second inlet 120 when the piston 130 is in the first end position 150 and the at least one transmission control command indicates that the piston 130 is to be moved to the second end position 160. Similarly, the transmission control unit 330 causes the second fluid flow F 2 to be supplied through the second inlet 120 before causing the first fluid flow F 1 to be supplied through the first inlet 110 when the piston 130 is in the second end position 150 and the at least one transmission control command indicates that the piston 130 is to be moved to the first end position 160.Preferably, the transmission control unit includes or is connected to a computer readable medium 335 storing a program for controlling the unit 330 according to the proposed principle.In summary, the basic method according to the invention for controlling the transmission actuating device will now be described with reference to the flow diagram of FIG. 4.A first step 410 checks whether or not the shift piston is to be moved (i.e., from either the first end position to the second or from the second end position to the first). If no such command has been received, the process loops back and remains at step 410. Otherwise, a step 415 follows. This step 415 checks whether the shift piston is currently in the first end position, and if so, a step 420 follows. Otherwise, i.e. if the shift piston is currently in the second end position, a step 440 follows.Step 420 initiates a supply of the first fluid flow F 1 through the first inlet 110 into the cylinder body 105. As a result, depending on the implementation, either a step 425 follows, which stops the first fluid flow F 1, or a step 430, wherein a supply of the second fluid flow F 2 through the second inlet 120 into the cylinder body 105 is triggered, follows. In either case, step 425 is completed before the process proceeds to a subsequent step 435. This step 435 checks whether or not the shift piston has reached the second end position, and if so, the process loops back to the step 410. Preferably, a sensor detects whether the piston has reached the end position or a timer is used. In the latter case, step 435 checks whether or not the timer has expired. If it was determined in step 435 that the shift piston has not yet reached the second end position, the process loops back to step 430 for further supply of the second fluid stream F2.Step 440 initiates a supply of the second fluid flow F2 through the second inlet 120 into the cylinder body 105. Subsequently, depending on the implementation, either a step 445 follows, which stops the second fluid flow F 2, or a step 450 follows, wherein a supply of the first fluid flow F 1 through the first inlet 110 into the cylinder body 105 is triggered. In either case, step 445 is completed before the process continues to a subsequent step 455. This step 455 checks whether or not the shift piston has reached the first end position, and if so, the process loops back to the step 410. Preferably, a sensor detects whether the piston has reached the end position or a timer is used. In the latter case, step 455 checks whether or not the timer has expired. If it has been determined in step 455 that the shift piston has not yet reached the first end position, the process loops back to step 450 for a further supply of the first fluid flow F 1.Each of the process steps, as well as a subsequence of steps described above with respect to Figure 4, may be controlled by means of a programmed computer apparatus. Moreover, although the embodiments of the invention described above with reference to the drawings comprise a computer apparatus and processes executed in a computer apparatus, the invention thus also extends to computer programs, particularly computer programs on or on a carrier, which are executed to implement the invention. The program may take the form of source code, machine code, code subsource, and machine code, such as in partially compiled form, or any other form suitable for use in implementing the process of the invention. The carrier may be any item or device capable of receiving the program. For example, the carrier may comprise a storage medium, such as a flash memory, a ROM (read-only memory), for example a CD (compact disc) or a semiconductor ROM, an EPROM (erasable programmable read-only memory), an EEPROM (electronic erasable programmable read-only memory), or a magnetically recordable medium, for example a floppy disk or a hard disk. Furthermore, the carrier may be a transmissible carrier, such as an electrical or optical signal, which may be transmitted via an electrical or optical cable or via radio or via other means. When the program is embodied by a signal which can be transmitted directly via a cable or other device or means, the carrier may be constituted by such cable or device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted to execute or use the relevant processes for its execution.The invention is not limited to the described embodiments in the drawings, but can be varied freely within the scope of the claims.

Claims

A transmission control system comprising: a transmission (320) configured to be arranged on a motor vehicle drive (325a, 325b), the transmission (320) having a transmission actuator (100) configured to cause at least one gear shift operation with respect to the transmission (320), the transmission actuator (100) comprising: a cylinder body (105) having a first inlet (110) and a second inlet (120), and a shift piston (130) movable between a first end position (150) and a second end position (160) within the cylinder body (105) in response to a first fluid flow (F1) supplied via the first inlet (110) and / or to a second fluid flow (F2) supplied via the second inlet (120); and a transmission control unit (330) configured to:, A method for operating the transmission operating device (100) in response to at least one transmission control command, characterized in that the transmission control unit (330) is configured to operate the transmission operating device (100) such that: when the piston (130) is in the first end position (150) and the at least one transmission control command indicates that the piston (130) is to be moved to the second end position (160), the first fluid flow (F1) is caused to be supplied through the first inlet (110) before the second fluid flow (F2) is caused to be supplied through the second inlet (120), and when the piston (130) is in the second end position (160) and the at least one transmission control command indicates that the piston (130) is to be moved to the first end position (150), the second fluid flow (F2) is caused to be supplied, The first fluid stream (F1) is caused to be supplied through the second inlet (120) before being caused to be supplied through the first inlet (110).System according to Claim 1, characterized in that the transmission control unit (330) is designed to actuate the transmission actuating device (100) in such a way that the supply of the first fluid stream (F1) is interrupted (t 1, t 11), at the latest when the supply of the second fluid stream (F2) is triggered (t 1).The system according to claim 2, characterized in that the transmission control unit (330) is configured to actuate the transmission actuating device (100) such that no fluid flow is supplied to the cylinder body (105) during a period (t 1- t 11) before the supply of the second fluid flow (F2) is triggered.The system according to claim 1, characterized in that the transmission control unit (330) is configured to actuate the transmission actuation device (100) such that the supply of the second fluid stream (F2) is triggered before the supply of the first fluid stream (F1) is stopped (t 21).The system according to any of the preceding claims, characterized in that the transmission control unit (330) is configured to actuate the transmission actuation device (100) such that the first and second fluid flows (F1, F2) have substantially identical stationary orders of magnitude (f1, f2).The system according to any of claims 1 to 4, characterized in that the transmission control unit (330) is configured to actuate the transmission actuation device (100) such that the first fluid stream (F1) has a stationary magnitude (f1) that is greater than the stationary magnitude (f2) of the second fluid stream (F2).The system according to any of claims 1 to 4, characterized in that the transmission control unit (330) is configured to actuate the transmission actuation device (100) such that the second fluid stream (F2) has a stationary magnitude (f2) that is greater than the stationary magnitude (f1) of the first fluid stream (F1).Motor vehicle (300), characterized in that it comprises a transmission control system according to one of Claims 1 to 7.A method for controlling a transmission actuating device (100) of a transmission (320) in a motor vehicle, the transmission actuating device (100) comprising a cylinder body (105) and a shift piston (130) movable between a first end position (150) and a second end position (160) within the cylinder body (105) in response to a first fluid flow (F1) supplied to the cylinder body (105) via a first inlet (110) and / or to a second fluid flow (F2) supplied to the cylinder body (105) via a second inlet (120), characterized in that when the piston (130) is in the first end position (150) and is moved to the second end position (160), the method comprises: initiating a supply of the first fluid stream (F1) through the first inlet (110) before initiating a supply of the second fluid stream (F2) through the second inlet (120).Method according to Claim 9, characterized bya termination (t 1, t 11) of the supply of the first fluid stream (F1) at the latest when the supply of the second fluid stream (F2) is triggered (t 1).Method according to claim 10, characterised in that, before the triggering of the supply of the second fluid flow (F2), the method has a period (t 1- t 11) during which no fluid flow is supplied for the cylinder body (105).Method according to claim 9, characterised bya triggering (t 1) the supply of the second fluid stream (F2) before a break (t 21) the supply of the first fluid stream (F1).Method according to one of Claims 9 to 12, characterized in that the first and second fluid streams (F1, F2) have substantially identical stationary orders of magnitude (f1, f2).Method according to one of Claims 9 to 12, characterized in that the first fluid stream (F1) has a stationary order of magnitude (f1) which is greater than a stationary order of magnitude (f2) of the second fluid stream (F2).Method according to one of Claims 9 to 12, characterized in that the second fluid stream (F2) has a stationary order of magnitude (f2) which is greater than a stationary order of magnitude (f1) of the first fluid stream (F1).A computer program directly loadable into the internal memory of a computer, comprising software for controlling the steps of any of claims 9 to 15 when said program is run on said computer.A computer readable medium (335) having a program stored thereon, the program causing a computer to control the steps of any one of claims 9 to 15.

Images