Control system for a multi-speed transmission and method thereof

Abstract

An electro-hydraulic control system for a multi-speed transmission having a plurality of torque transmitting mechanisms includes a controller for operatively controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque transmitting mechanisms operatively selectable between a stressed and unstressed condition to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having a pressure control solenoid and a trim valve. The system can also include one or more shift valves disposed in fluid communication with the fluid source and movable between a stroked and an un-stroked position. In any given range, only two of the plurality of torque transmitting mechanisms can be stressed. Further, three of the plurality of pressure control solenoids are normally high solenoids and the remaining solenoids are normally low solenoids.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 527,202, filed June 30, 2017, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a method for controlling a transmission system, and more particularly to a method for controlling hydraulic fluid for a multi-stage transmission. Background Technology

[0004] Multi-stage transmissions utilize numerous friction clutches or brakes, planetary gear sets, shafts, and other components to achieve multiple gear ratios or speed ratios. The transmission architecture—the package or layout of the aforementioned components—is determined based on cost, size, packaging constraints, and desired ratios. A control system is required to manage these components and provide the desired shift quality. Furthermore, to improve fuel economy and for other reasons, with an increased range, the control system must ensure that the correct clutch or brake is engaged within any given range and further provide fault range in the event of a power failure. The complexity of the control system continues to increase with the increased forward and reverse gear ranges for any given multi-stage transmission. Summary of the Invention

[0005] In one embodiment of this disclosure, an electro-hydraulic control system for a multi-stage transmission includes: a controller for operable control of the transmission; a fluid source for supplying hydraulic fluid; a plurality of torque transmission mechanisms operablely selectable between a stressed and unstressed state to achieve a plurality of ranges including at least one reverse gear, neutral gear, and a plurality of forward gear ranges, wherein in any one of the plurality of forward gear ranges, only two of the plurality of torque transmission mechanisms are in the stressed state; and a plurality of fine-tuning systems electrically connected to the controller and fluidly connected to the fluid source, wherein the plurality of fine-tuning systems... Each of the adjustment system includes a pressure-controlled solenoid valve and a fine-tuning valve; a plurality of shift valves, each configured to be in fluid communication with the fluid source and to move between a traveling position and a non-traveling position, the plurality of shift valves including at least a first shift valve, a second shift valve, and a third shift valve; wherein, during a shift from one of the plurality of forward gear ranges to neutral, hydraulic fluid in the system abuts against at least one of the first, second, and third shift valves to form a latch, such that the latch holds at least one of the first, second, and third shift valves in its traveling position.

[0006] In a first example of the present embodiment, the latch is formed by a check valve located between the at least one of the first, second, and third shift valves and a drain passage. In a second example, the at least one of the first, second, and third shift valves is flow-communicably biased to move from its engaged position to its disengaged position during the shift to neutral. In a third example, three of the first, second, third, fourth, and fifth pressure control solenoids comprise normally-high solenoids, and the other two solenoids comprise normally-low solenoids. In a fourth example, a pressure switch can be provided in fluid communication with the at least one of the first, second, and third shift valves and in electrical communication with the controller, the pressure switch configured to detect a position of the at least one of the first, second, and third shift valves.

[0007] In a fifth example, a first torque transmission mechanism and a second torque transmission mechanism are in their force-applied states in a first range of the plurality of forward gear ranges; and the first torque transmission mechanism remains in its force-applied state, and the second torque transmission mechanism bleeds to its force-unapplied state during the shift to neutral. In a sixth example, the latch is formed by a flow restriction and a check valve located between the at least one of the first, second, and third shift valves and a drain passage.

[0008] In another embodiment of the present disclosure, an electro-hydraulic control system for a multi-speed transmission includes a controller for operatively controlling the transmission, a fluid source for supplying hydraulic fluid, a plurality of torque transfer mechanisms operatively selectable between a force applied and a force not applied state to achieve a plurality of ranges including at least one reverse range, a neutral range, and a plurality of forward range ranges, wherein in any of the plurality of forward range ranges only two of the plurality of torque transfer mechanisms are in the force applied state, a plurality of trim systems in electrical communication with the controller and in fluid communication with the fluid source, wherein each of the plurality of trim systems includes a pressure control solenoid and a trim valve, a plurality of shift valves each disposed in fluid communication with the fluid source and configured to move between a stroked position and a de-stroked position, the plurality of shift valves including at least a first shift valve, a second shift valve, and a third shift valve, a first shift solenoid and a second shift solenoid each disposed in electrical communication with the controller, the first shift solenoid operatively controlled between an energized and a de-energized state to control movement of the first and second shift valves, and the second shift solenoid operatively controlled between an energized and a de-energized state to control movement of the third shift valve, wherein in a first forward range range of the plurality of forward range ranges, a first torque transfer mechanism and a second torque transfer mechanism are in their force applied state, the first shift solenoid is energized to control movement of the first and second shift valves to their stroked positions such that hydraulic fluid at a head of each of the first and second shift valves forces the two shift valves to move to their stroked positions, and further wherein when shifting from the first forward range range to the neutral range, the first torque transfer mechanism remains in its force applied state as the only force applied torque transfer mechanism, and the second torque transfer mechanism is vented.

[0009] In one example of the present embodiment, a latch is formed by hydraulic fluid in the system against at least one of the first, second, and third shift valves when shifting from the first forward range range to the neutral range. In a second example, at least one of the first and second shift valves is maintained in their stroked positions due to the latch. In a third example, the first and second shift valves are maintained in their stroked positions due to the latch. In another example, the latch is formed by a check valve located between the at least one of the first, second, and third shift valves and a vent passage. In yet another example, the latch is formed by a flow restriction and check valve located between the at least one of the first, second, and third shift valves and a vent passage. In still another example, a pressure switch can be disposed in fluid communication with the at least one of the first, second, and third shift valves and in electrical communication with the controller, the pressure switch configured to detect a position of the at least one of the first, second, and third shift valves.

[0010] In yet another embodiment of the present disclosure, an electro-hydraulic control system for a multi-speed transmission includes a controller for operatively controlling the transmission, a fluid source for supplying hydraulic fluid, a plurality of torque transfer mechanisms operatively selectable between a force applied and a force not applied state to achieve a plurality of ranges including at least one reverse range, a neutral range, and a plurality of forward range ranges, wherein in any of the plurality of forward range ranges only two of the plurality of torque transfer mechanisms are in the force applied state, a plurality of trim systems in electrical communication with the controller and in fluid communication with the fluid source, wherein each of the plurality of trim systems includes a pressure control solenoid and a trim valve, a plurality of shift valves each disposed in fluid communication with the fluid source and configured to move between a stroked position and an un-stroked position, the plurality of shift valves including at least a first shift valve, a second shift valve, and a third shift valve, a first shift solenoid disposed in electrical communication with the controller, the first shift solenoid operatively controlled between an energized and a de-energized state to control movement of the first and second shift valves, and a second shift solenoid disposed in electrical communication with the controller, the second shift solenoid operatively controlled between an energized and a de-energized state to control movement of the third shift valve, wherein movement of the first shift valve between its stroked and un-stroked positions is operatively controlled by the controller to select a desired range of the plurality of ranges.

[0011] In one example of the present embodiment, in the neutral and at least one reverse range, the controller operatively controls movement of the first shift valve to its un-stroked position, and in each of the plurality of forward range ranges, the controller operatively controls movement of the first shift valve to its stroked position. In another example, a plurality of pressure switches are disposed in electrical communication with the controller, the plurality of pressure switches including at least a first pressure switch, a second pressure switch, and a third pressure switch. In yet another example, the first pressure switch is in fluid communication with the first shift valve to detect its position, the second pressure switch is in fluid communication with the second shift valve to detect its position, and the third pressure switch is in fluid communication with the third shift valve to detect its position.

[0012] In still another example, in the neutral and at least one reverse range, the controller operatively controls movement of the first shift valve to its un-stroked position, in each of the plurality of forward range ranges, the controller operatively controls movement of the first shift valve to its stroked position, the first pressure switch is pressurized or not pressurized based on the position of the first shift valve, and the controller operatively detects the position of the first shift valve based on whether the first pressure switch is pressurized or not pressurized.

[0013] In another example of this embodiment, the system may include: a fourth pressure switch configured to be in fluid communication with a first fine-tuning system among the plurality of fine-tuning systems; and a first torque transmission mechanism among the plurality of torque transmission mechanisms, which is in fluid communication with the first fine-tuning system; wherein the fourth pressure switch is pressurized or depressurized based on the position of the fine-tuning valve of the first fine-tuning system; further, wherein the position of the fine-tuning valve and the first torque transmission mechanism in their stressed or unstressed state are operably detected by the controller based on whether the fourth pressure switch is pressurized. Attached Figure Description

[0014] The foregoing aspects of this disclosure and how they are obtained will become more apparent from the following description of embodiments thereof, taken in conjunction with the accompanying drawings, and the disclosure itself will be better understood, wherein:

[0015] Figure 1 These are block diagrams and schematic diagrams illustrating one embodiment of a powertrain system;

[0016] Figure 2 This is a partial control diagram of a multi-stage transmission system;

[0017] Figure 3 In reverse gear Figure 2 A schematic diagram of the hydraulic control system;

[0018] Figure 4 In neutral or parked Figure 2 A schematic diagram of the hydraulic control system;

[0019] Figure 5 It is in the first range Figure 2 An embodiment of the hydraulic control diagram of the system;

[0020] Figure 6 It is in the first range Figure 2 Another embodiment of the hydraulic control diagram of the system;

[0021] Figure 7 It is in the second range Figure 2 A schematic diagram of the hydraulic control system;

[0022] Figure 8 It is in the third range Figure 2 A schematic diagram of the hydraulic control system;

[0023] Figure 9 It is in the fourth range Figure 2 A schematic diagram of the hydraulic control system;

[0024] Figure 10 It is in the fifth rangeFigure 2 A schematic diagram of the hydraulic control system;

[0025] Figure 11 It is in the sixth range Figure 2 A schematic diagram of the hydraulic control system;

[0026] Figure 12 It is in the seventh range Figure 2 A schematic diagram of the hydraulic control system;

[0027] Figure 13 It is in the eighth range Figure 2 A schematic diagram of the hydraulic control system;

[0028] Figure 14 It is in the ninth range Figure 2 A schematic diagram of the hydraulic control system;

[0029] Figure 15 It is within the first power outage range Figure 2 A schematic diagram of the hydraulic control system;

[0030] Figure 16 It is within the second power outage range Figure 2 A schematic diagram of the hydraulic control system;

[0031] Figure 17 It is within the third power outage range Figure 2 A schematic diagram of the hydraulic control system;

[0032] Figure 18 This is an embodiment of a schematic diagram of the first shift valve;

[0033] Figure 19 This is a schematic diagram of one embodiment of the second shift valve;

[0034] Figure 20 This is a schematic diagram of one embodiment of the third shift valve;

[0035] Figure 21 yes Figure 2 An example of the mechanization of a multi-stage transmission system;

[0036] Figure 22 yes Figure 2 An example of a shift availability table for a multi-stage transmission system; and

[0037] Figure 23 Is Figures 3-17 A diagram illustrating different fluid lines or paths in a hydraulic control system.

[0038] Use the corresponding reference numerals to indicate the corresponding parts that span several views. Detailed Implementation

[0039] The embodiments of the present disclosure described below are not intended to be exhaustive or to limit the present disclosure to the precise form disclosed in the following detailed description. Rather, the described embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the present disclosure.

[0040] The terminology used herein is for the purpose of describing particular illustrative embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the use of the term "and / or" as used herein refers to a combination or any number of items listed with that term and does not require mutual exclusivity of those items. Likewise, the use of the terms "one or more of' as used herein refers to at least one, and includes individual items or a combination of two or more items. It will be further understood that the terms "comprises" and "comprising," or "includes" and / or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as requiring the particular order in which they are discussed or illustrated, unless specifically identified as an order of execution. It is also to be understood that additional or alternative steps can be employed.

[0041] Referring now to Figure 1 illustrates a block and schematic diagram of one illustrative embodiment of a vehicle system 100 having a drive unit 102 and a transmission 118. In the illustrative embodiment, the drive unit 102 can include an internal combustion engine, a diesel engine, an electric motor, or other power producing device. The drive unit 102 is configured to rotatably drive an output shaft 104 that is coupled to an input shaft or pump shaft 106 of a conventional torque converter 108. The input shaft or pump shaft 106 is coupled to an impeller or pump 110 that is rotatably driven by the output shaft 104 of the drive unit 102. The torque converter 108 further includes a turbine 112 that is coupled to a turbine shaft 114 that is coupled to, or integral with, a rotatable input shaft 124 of the transmission 118. The transmission 118 can also include an internal pump 120 for establishing pressure within different flow circuits (e.g., a main circuit, a lube circuit, etc.) of the transmission 118. The pump 120 can be driven by a shaft 116 that is coupled to the output shaft 104 of the drive unit 102. In this arrangement, the drive unit 102 can transmit torque to the shaft 116 for driving the pump 120 and establishing pressure within the different circuits of the transmission 118.

[0042] The transmission 118 can include a planetary gear train 122 having a number of automatically selected gears. An output shaft 126 of the transmission 118 is coupled to or integral with a propeller shaft 128, and rotatably drives the propeller shaft 128, which is coupled to a conventional universal joint 130. The universal joint 130 is coupled to an axle 132, and rotatably drives the axle 132, which has wheels 134A and 134B mounted to each end thereof. The output shaft 126 of the transmission 118 drives the wheels 134A and 134B in a conventional manner through the propeller shaft 128, the universal joint 130, and the axle 132.

[0043] A conventional lock-up clutch 136 is connected between the pump 110 and the turbine 112 of the torque converter 108. Operation of the torque converter 108 is conventional, wherein the torque converter 108 can operate in a so-called "torque converter" mode under certain operating conditions, such as vehicle launch, low speed, and certain gear shift conditions. In torque converter mode, the lock-up clutch 136 is disengaged, and the pump 110 rotates at the rotational speed of the drive unit output shaft 104, while the turbine 112 is rotatably actuated by the pump 110 through fluid (not shown) interposed between the pump 110 and the turbine 112. In this mode of operation, torque multiplication occurs through the flowable coupling, such that the turbine shaft 114 is exposed to drive a greater torque than that supplied by the drive unit 102, as is known in the art. The torque converter 108 can alternatively operate in a so-called "lock-up" mode under other operating conditions, such as when torque multiplication is not needed. In lock-up mode, the lock-up clutch 136 is engaged and the pump 110 is thereby directly fastened to the turbine 112, such that the drive unit output shaft 104 is directly coupled to the input shaft 124 of the transmission 118, as is also known in the art.

[0044] The transmission 118 further includes an electro-hydraulic system 138 that selectively flows fluid through a number J of fluid paths 1401-140 J The electro-hydraulic system 138 is flowably coupled to the planetary gear train 122, wherein J can be any positive integer. The electro-hydraulic system 138 is responsive to control signals to selectively flow fluid through the fluid paths 1401-140 Jone or more of the plurality of friction devices in the planetary gear set 122 (i.e., engagement and disengagement). The plurality of friction devices can include, but are not limited to, one or more conventional brake devices, one or more torque transfer devices, etc. Generally, the operation (i.e., engagement and disengagement) of the plurality of friction devices is controlled by selectively controlling the frictional force applied by each of the plurality of friction devices, such as by controlling the fluid pressure to each of the friction devices. In one example embodiment, which is not intended to be limiting, the plurality of friction devices includes a plurality of brakes and torque transfer devices in the form of conventional clutches, which are each controllably engageable and disengageable by fluid pressure supplied by the electro-hydraulic system 138. In any case, the shifting or changing between the various gears of the transmission 118 is accomplished in a conventional manner by selectively controlling the plurality of friction devices (by controlling the fluid pressure in the plurality of fluid paths 1401-140 J

[0045] The system 100 further includes a transmission control circuit 142, which can include a memory unit 144. The transmission control circuit 142 is illustratively microprocessor-based, and the memory unit 144 generally includes instructions stored therein that are executable by a processor of the transmission control circuit 142 to control the operation of the torque converter 108 and the operation of the transmission 118, i.e., shifting between the various gears of the planetary gear set 122. However, it should be understood that the present disclosure contemplates other embodiments in which the transmission control circuit 142 is not microprocessor-based, but is configured to control the operation of the torque converter 108 and / or the transmission 118 based on one or more sets of hardwired instructions and / or software instructions stored in the memory unit 144.

[0046] In Figure 1 In the illustrated system 100, the torque converter 108 and the transmission 118 include a number of sensors that are configured to generate sensor signals indicative of one or more operating conditions of the torque converter 108 and the transmission 118, respectively. For example, the torque converter 108 illustratively includes a conventional speed sensor 146 that is positioned and configured to generate a speed signal corresponding to the rotational speed of the pump shaft 106, which is the same as the rotational speed of the output shaft 104 of the drive unit 102. The speed sensor 146 is electrically connected to a pump speed input PS of the transmission control circuit 142 by a signal path 152, and the transmission control circuit 142 is operable to process the speed signal generated by the speed sensor 146 in a conventional manner to determine the rotational speed of the pump shaft 106 / drive unit output shaft 104.

[0047] ​The transmission 118 illustratively includes another conventional speed sensor 148 positioned and configured to generate a speed signal corresponding to the rotational speed of the transmission input shaft 124, which is the same as the rotational speed of the turbine shaft 114. The input shaft 124 of the transmission 118 is directly coupled to, or integral with, the turbine shaft 114, and the speed sensor 148 can alternatively be positioned and configured to generate a speed signal corresponding to the rotational speed of the turbine shaft 114. In either case, the speed sensor 148 is electrically connected by a signal path 154 to a transmission input shaft speed input TIS of the transmission control circuit 142, and the transmission control circuit 142 is operable to process the speed signal generated by the speed sensor 148 in a conventional manner to determine the rotational speed of the turbine shaft 114 / transmission input shaft 124.

[0048] The transmission 118 further includes yet another speed sensor 150 positioned and configured to generate a speed signal corresponding to the rotational speed of the output shaft 126 of the transmission 118. The speed sensor 150 can be conventional, and is electrically connected by a signal path 156 to a transmission output shaft speed input TOS of the transmission control circuit 142. The transmission control circuit 142 is configured to process the speed signal generated by the speed sensor 150 in a conventional manner to determine the rotational speed of the transmission output shaft 126.

[0049] In the illustrative embodiment, the transmission 118 further includes one or more actuators configured to control various operations within the transmission 118. For example, the electro-hydraulic system 138 illustratively described herein includes a number of actuators, e.g., conventional solenoids or other conventional actuators, connected by a corresponding number of signal paths 721-72 J to the transmission control circuit 142. J Where J can be any positive integer as described above. Each actuator within the electro-hydraulic system 138 is responsive to a corresponding one of the control signals CP1-CP J generated by the transmission control circuit 142 on a corresponding one of the signal paths 721-72 J to control the friction exerted by each of the plurality of friction devices by controlling the pressure of the fluid within one or more corresponding fluid passages 1401-140 J and, thus, the operation, i.e., engagement and disengagement, of one or more corresponding friction devices based on information provided by the various speed sensors 146, 148, and / or 150.

[0050] Friction devices of planetary gear set 122 are illustratively controlled by hydraulic fluid distributed by electro-hydraulic system 138 in a conventional manner. For example, electro-hydraulic system 138 illustratively includes a conventional hydraulic positive displacement pump 120 that distributes fluid to one or more friction devices through control of one or more actuators within electro-hydraulic system 138. In the present embodiment, control signals CP1-CP J Illustratively analog friction device pressure commands, the one or more actuators respond to the commands to control hydraulic pressure to the one or more friction devices. However, it should be understood that friction exerted by each of the plurality of friction devices can alternatively be controlled according to other conventional friction device control structures and techniques, and such other conventional friction device control structures and techniques are contemplated by the present disclosure. In either case, however, analog operation of each friction device is controlled by control circuit 142 according to instructions stored in memory unit 144.

[0051] In the illustrative embodiment, system 100 further includes drive unit control circuit 160 having an input / output port (I / O) electrically coupled to the drive unit 102 through a number K of signal paths 162, where K can be any positive integer. Drive unit control circuit 160 can be conventional and is operable to control and manage overall operation of drive unit 102. Drive unit control circuit 160 further includes a communication port COM electrically connected to a similar communication port COM of transmission control circuit 142 through a number L of signal paths 164, where L can be any positive integer. The one or more signal paths 164 are typically collectively referred to as a data link. In general, drive unit control circuit 160 and transmission control circuit 142 are operable to share information in a conventional manner through one or more signal paths 164. For example, in one embodiment, drive unit control circuit 160 and transmission control circuit 142 are operable to share information in the form of one or more messages through one or more signal paths 164 according to the Society of Automotive Engineers (SAE) J-1939 communication protocol, although other embodiments are contemplated by the present disclosure in which drive unit control circuit 160 and transmission control circuit 142 are operable to share information through one or more signal paths 164 according to one or more other conventional communication protocols (e.g., from a conventional data bus such as a J1587 data bus, a J1939 data bus, an IESCAN data bus, a GMLAN, a Mercedes PT-CAN).

[0052] Referring now to Figure 2 which shows a hydraulic control system for a multi-speed transmission system 200. The system 200 can include Figure 1similar features of the transmission 118 of FIG. 1. For example, the system 200 can include a torque converter 202 or other flowable coupling device for flowably coupling the transmission system 200 to the engine or other drive unit 102. The torque converter 202 can include a lock-up clutch (not shown) similar to the lock-up clutch 136 of FIG. 1. In addition, the transmission system 200 can include a primary fluid pump 204 for providing hydraulic fluid and pressure throughout the system. The pump 204 can be similar to the internal pump 120 of FIG. 1. Here, the pump 204 is flowably coupled to a reservoir 206 or sump that provides fluid to the suction side of the pump 204. In this disclosure, the pump 204 can be referred to as the fluid or pressure source of the system 200. Figure 1 Figure 1

[0053] The transmission system 200 can include other systems or subsystems, such as a pressure regulator system, a lubrication oil system, a converter system, and a cooler system. In Figure 2 , the transmission system 200 can include a primary regulator 208 in fluid communication with the pump 204. The primary regulator 208 can be a valve or other fluid regulating mechanism for regulating the primary pressure in the system 200. In this disclosure, all of the primary pressure can be provided to the transmission system 200 by the pump 204. The primary regulator 208 can regulate this pressure, and as will be described below, can trigger other solenoids and the like to further regulate the primary pressure. Regardless, the primary regulator forms part of the pressure regulator system, and the primary pressure flows from the primary regulator 208 to a primary pressure line 218 of the transmission system 200, as will be described below.

[0054] The primary regulator 208 is further flowably coupled to a converter system. The converter system can include the torque converter 202, a converter release 210, and a converter flow 214. In one example, the converter release 210 and the converter flow 214 can be valves. Hydraulic fluid can flow from the primary regulator 208 to the converter release 210 and the converter flow 214. In addition, fluid can flow from the converter flow 214 through a converter in passage 222 to the torque converter 202, and fluid can flow from the torque converter 202 through a converter out passage 220 to the converter flow 214. In this manner, fluid pressure can flow to and from the torque converter to better regulate the fluid operating temperature in the torque converter 202, and to provide cooler fluid to protect the lock-up clutch (if applicable). There can be other reasons or advantages for flowably coupling the torque converter 202 to the converter flow 214, as can be appreciated by the skilled artisan.

[0055] ​​The transmission system 200 may also include a lubrication system and a cooler system. The lubrication system may include a lubrication regulator 212 for regulating pressure to cool clutches, brakes, etc., in the system 200. The cooler system may include a cooler 216, such as a vehicle cooler, that can be disposed outside the transmission system 200. However, the cooler 216 may be in fluid communication with the converter flow 214 and the lubrication regulator 212, as in… Figure 2 As shown in the diagram. Cooler 216 may be further configured to provide cooler flow 224 to the lubricating oil line.

[0056] Figure 2 This is just one embodiment of the transmission system. Other components or systems may exist, forming a connection with... Figure 2 The embodiments shown are a subset of different embodiments. The teachings of this disclosure are not intended to be limited to any particular embodiment.

[0057] This disclosure provides an electro-hydraulic control system for controlling a multi-stage transmission. The multi-stage transmission may include multiple forward and reverse gear ratios. Furthermore, the multi-stage transmission may include an input end, an output end, multiple planetary gear sets, and multiple torque transmission mechanisms that can selectively engage to achieve multiple forward and reverse gear ratios. In one example, the multi-stage transmission may be a nine-stage transmission having an input end, an output end, a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set. Each planetary gear set may be disposed between the input end and the output end, and each planetary gear set may include a sun gear, a ring gear, and a carrier component. Additionally, in this example, the transmission may include multiple interconnecting components for interconnecting and connecting the planetary gear sets and torque transmission mechanisms to the input end and the output end. A non-limiting example of a multi-stage transmission architecture controllable by the teachings of this disclosure is disclosed in U.S. Patent No. 7,364,527, issued April 29, 2008, and assigned to General Motors Corporation, the disclosure of which is incorporated herein by reference.

[0058] See Figures 3-17 It illustrates an electro-hydraulic control system 300 for a multi-stage transmission with multiple ranges including at least one neutral gear and one reverse gear range. The electro-hydraulic control system 300 can be used with... Figure 1 The electro-hydraulic system 138 is similarly positioned. Specifically, the electro-hydraulic control system 300 can be used with, for example... Figure 1 The controller of the transmission control circuit 142 shown is electrically connected. Furthermore, the electro-hydraulic control system 300 may include a means for fluidly connecting to the planetary gear train 122 (such as...). Figure 1 Multiple fluid paths (e.g., fluid paths 1401-140) of the planetary gear system shown in the diagram j). In other embodiments, the control system 300 can be electrically coupled or flowably coupled to other systems or subsystems of the multi-speed transmission system.

[0059] The electro-hydraulic control system 300 can include a number of valves and solenoids for controlling the selective engagement of one or more clutches or brakes. For the purposes of this disclosure, each clutch or brake can be referred to as a torque transfer mechanism. Further, and as will be described below, the system 300 can include pressure switches for detecting pressure within certain lines or fluid paths in the system 300. Other mechanisms will be described in this disclosure. Notably, Figures 3-17 Only one embodiment of an electro-hydraulic control system for a multi-speed transmission is shown. However, the present disclosure is not intended to be limited to only this embodiment.

[0060] Turning specifically to Figure 3 , the electro-hydraulic control system 300 can be in fluid communication with the transmission system 200 of Figure 2 . In particular, a fluid source 302 to the control system 300 can be flowably coupled to the pump 204 through the main regulator 208 and the main pressure line 218. Hydraulic fluid can be supplied from the pump 204 to the control system 300 and regulated by the main regulator 208. As such, the fluid from the pressure source 302 can be referred to as main pressure. Various fluid pressures and fluid lines in the electro-hydraulic control system 300 are identified in the legend shown in the figures in the Figure 23 of this disclosure. These fluid pressures include main pressure, control main pressure, drain backfill pressure, drain pressure, main modulator pressure, torque converter lockup clutch signal pressure, torque converter lockup clutch pressure, pressure control solenoid signal pressure, and clutch pressure. In other embodiments, additional or fewer signal pressures or fluid pressures can be present in the control system, and the illustrative embodiments of the present disclosure are not intended to be limited in this manner.

[0061] Referring to Figure 3 , the electro-hydraulic control system 300 can include a number of trim systems, with each trim system including a solenoid and a trim valve. For example, a first trim system can include a torque converter clutch trim solenoid 304 (i.e., TCC solenoid) and a torque converter clutch trim valve 306. Also shown is an accumulator (to the left of the solenoid 304 in Figure 3 ) adjacent to the TCC trim solenoid 304, but not labeled. Activation of the TCC trim system can provide hydraulic fluid through a TCC flow path to a converter flow 214. Fluid can flow from the converter flow 214 to force the lockup clutch of the torque converter 202 through a converter in the flow path 222. This is best shown in Figure 2 and 6 .

[0062] Figures 3-17 Each of the trim systems depicted in FIG. 2 includes an accumulator, but in other embodiments, not every trim system includes an accumulator. An accumulator is a small valve that travels according to the output pressure of the solenoid. When it is traveling or not traveling, a large amount of fluid from the solenoid output flows back through the solenoid. The accumulator can be any conventional mechanism for providing a more stable control system.

[0063] The second trim system includes a first pressure control solenoid 308 and a first pressure control trim valve 310. The trim system can include an accumulator as shown. Figure 3 The first pressure control solenoid 308 can be referred to as a normally high pressure control solenoid. For the purposes of this disclosure, a normally high pressure control solenoid outputs full pressure when there is no current supplied to the solenoid. In other words, if the power is off or disconnected from the first pressure control solenoid 308, its default position is to output full pressure to cause the first pressure control trim valve 310 to travel.

[0064] As also shown, hydraulic fluid can flow through the second trim system to apply force to a first torque transmission mechanism CI. CI can be a clutch or a brake. In Figure 3 In FIG. 2, CI is not under force and the hydraulic fluid is bled off to refill, as shown. Bleed off and bleed back can simply mean that the hydraulic fluid is released or returned to the reservoir 206.

[0065] Figure 3 Another trim system in FIG. 2 includes a second pressure control solenoid 312 and a second pressure control trim valve 314. Similar to the first pressure control solenoid 308, the second pressure control solenoid 312 can be a normally high pressure control solenoid. Thus, if the power is off or disconnected from the second pressure control solenoid 312, it defaults to full output pressure to cause the second pressure control trim valve 314 to travel.

[0066] Still another trim system in the control system 300 includes a third pressure control solenoid 316 and a third pressure control trim valve 318. Similar to the first and second trim solenoids, the third pressure control solenoid 316 can be a normally high pressure control solenoid. Thus, if the power is off or disconnected from the third pressure control solenoid 316, it defaults to full output pressure to cause the third pressure control trim valve 318 to travel. Further, when the third pressure control trim valve 318 is traveling, hydraulic fluid is able to flow and apply force to a third torque transmission mechanism C3. Similar to CI, C3 can be a clutch or a brake.

[0067] The electro-hydraulic control system 300 further includes a fine-tuning system formed by a fourth pressure control solenoid valve 320 and a fourth pressure control fine-tuning valve 322. The fourth pressure control solenoid valve 320 may be a normally low pressure control solenoid valve. Therefore, unlike a normally high pressure control solenoid valve, the normally low pressure control solenoid valve generates zero output pressure when no current is supplied to the solenoid valve. If the fourth pressure control solenoid valve 320 is actuated or energized by the transmission controller or control circuit and is de-energized, the fourth pressure control solenoid valve 320 defaults to zero output pressure and the fourth pressure control fine-tuning valve 322 does not move.

[0068] This fine-tuning system can also control the fluid pressure to the fourth torque transmission mechanism C4. C4 can be a clutch or brake. When the fourth pressure control fine-tuning valve 322, or only the fourth fine-tuning valve, is moved to its traveling position, fluid pressure can fill and apply force to C4. However, when de-energized, the fourth pressure control solenoid valve 320 is de-energized, and the fourth fine-tuning valve 322 is not traveling, thus preventing the hydraulic fluid from applying force to C4. This will be described further below.

[0069] Another fine-tuning system in the control system 300 includes a fifth pressure control solenoid valve 324 and a fifth pressure control fine-tuning valve 326. In this embodiment, the fifth pressure control solenoid valve 324 is another normally low-pressure control solenoid valve, which defaults to zero output pressure when current is no longer supplied to the solenoid valve. Therefore, when power is off, the fifth pressure control fine-tuning valve 326, or simply put, the fifth fine-tuning valve 326, does not move.

[0070] like Figure 3 As shown, the fifth pressure control solenoid valve 324 and the fifth fine-tuning valve 326 control the hydraulic fluid to apply force to the sixth torque transmission mechanism C6. C6 can be a clutch or brake. When the fifth fine-tuning valve 326 is in motion, fluid can fill and apply force to C6. When the valve is not in motion, no force can be applied to C6. Another feature of this fine-tuning system is the inclusion of a pressure-boosting plug 328. The pressure-boosting plug 328 may include a hollow opening or channel 344 defined therein for fluid to pass through the plug 328 and move the fifth fine-tuning valve 326. As will be described below, the pressure-boosting plug 328 allows different gains to be achieved by means of this fine-tuning system.

[0071] The control system 300 may further include a second torque transmission mechanism C2 and a fifth torque transmission mechanism C5. C2 and C5 may be clutches or brakes. Hydraulic fluid for applying force to C2 or C5 may flow through a fluid passage defined by the relative position of the second fine-tuning valve 314.

[0072] Figure 3The electro-hydraulic control system 300 further illustrates a pair of on-off shift solenoid valves 330, 332. Each solenoid valve can be energized or de-energized by a controller (e.g., a transmission controller or transmission control circuit 142). When a solenoid valve is energized, i.e., it is considered "open," the solenoid valve can output control pressure. When a solenoid valve is de-energized, i.e., it is referred to as "closed," the solenoid valve does not output any control pressure.

[0073] In this disclosure, the control pressure is the pressure fed from the main pressure line 218 or pressure source 302, but it is regulated at a maximum pressure typically below the main pressure. Furthermore, the control pressure, i.e., the "control main pressure," is referred to as the feed pressure to all actuators. The control pressure may be regulated, for example, at 110 psi. This is just one example, as the control pressure may be regulated at different pressures for other embodiments. In contrast, the main pressure may exceed the control pressure based on specific torque requirements of the transmission. For example, in one embodiment, the main pressure may vary between 50 psi and 250 psi, while the control pressure may be limited to the regulated pressure (e.g., 110 psi).

[0074] The solenoid valves in the control system 300 can be controlled using control pressure, such that the maximum output pressure of the solenoid valves is the control pressure. To achieve the control pressure, a main pressure is supplied from pressure source 302 to control main valve 334. The hydraulic fluid flowing out of control main valve 334 is the control pressure, which then flows through control main filter 336 to remove any debris or unwanted particles from the fluid. The control pressure then flows to each of the aforementioned pressure-controlled solenoid valves and on / off solenoid valves. The control pressure can also be fed in via different actuators or shift valves, which will be described below. Furthermore, the control pressure pressurizes the pressure switches in the control system 300.

[0075] Another mechanism used to reduce or further regulate the main pressure is the main modulation solenoid valve 340. The main modulation solenoid valve 340 outputs a reduced main pressure and can be energized and de-energized by a controller. Although Figure 3 Not shown, but the modulated main pressure from the main modulating solenoid valve 340 can flow to Figure 2 The main regulator 208 in the middle increases or decreases the main pressure based on the output of the solenoid valve.

[0076] The control system 300 includes several different valves, including a discharge backfill pressure reducing valve 338 and a discharge backfill valve 342. In each case, fluid pressurized by either valve can be discharged into the reservoir 206. Another type of valve in the control system 300 is a check valve 352. Figure 3In the illustrative embodiment, there are several check valves 352 shown in the various paths to limit or prevent flow in a certain direction of the flow path. The check valves 352 can be any conventional check valve for the purposes of the present disclosure.

[0077] The control system 300 further includes a plurality of shift valves or actuators. The shift valves can function differently than the trim valves. For example, the aforementioned trim valves can be used to modulate pressure to a desired clutch pressure. Here, the main pressure can be trimmed to a desirable clutch or trim pressure. On the other hand, the shift valves divert or redirect hydraulic fluid from one flow path to a different flow path.

[0078] In Figures 3-17 The control system 300 can include a first shift valve 346, a second shift valve 348, and a third shift valve 350 in the illustrative embodiment. The function of each shift valve will be described below, particularly each range and failure range. However, the second shift valve 348 can feed clutch pressure directly to the second torque transfer mechanism C2 and the fifth torque transfer mechanism C5. In this control system 300, for a given range, only one of C2 and C5 is applied.

[0079] Each of the shift valves can move between a stroked position and an unstroked position. To do so, a first shift solenoid 330 can be configured to actuate the first and second shift valves, and a second shift solenoid 332 can be configured to actuate the third shift valve 350. The manner in which each shift valve is actuated in a given range will be further described below.

[0080] In Figure 3 Another valve shown in the control system 300 includes a boost valve 354. The boost valve 354 and the second trim valve 314 can control hydraulic fluid to C2 and C5, which will be described below.

[0081] The control system 300 further includes a first pressure switch 356, a second pressure switch 358, a third pressure switch 360, and a fourth pressure switch 362. Each pressure switch can actuate between a first position and a second position. In the first position, the pressure switch is pressurized, and in the second position, the pressure switch is not pressurized. Based on the position, the controller can detect the position and gain of the different valves of the overall control system 300.

[0082] In the present disclosure, the control system 300 is such that two torque transfer mechanisms are applied. For example, see Figure 21 which provides a mechanized table 2100 of a multi-speed transmission. In this table 2100, a plurality of forward ranges, a neutral range, and a reverse range are shown. In the present embodiment, there are nine forward ranges, but for other embodiments, a different number of forward and reverse ranges can be present. The present disclosure is not limited to any number of forward and reverse ranges.

[0083] Figure 21 The columns of Table 2100 further illustrate the different solenoid valves. As shown, shift solenoid valves 330 and 332 are shown as normally low solenoid valves (“N / L”), and fourth pressure control solenoid valve 320 and fifth pressure control solenoid valve 324. First pressure control solenoid valve 308, second pressure control solenoid valve 312, and third pressure control solenoid valve 316 are shown as normally high solenoid valves (“N / L”) in Table 2100. In the table, zero (“0”) identifies the solenoid valve as closed or not receiving current, while one (“1”) indicates the solenoid valve as open or receiving current (i.e., energized). The pressure control solenoid valves indicate which clutch can be forceped in each range. The following table illustrates one embodiment of engagement or force applied to at least two torque transmission mechanisms:

[0084] Steady state range Engagement torque transmission mechanism Engagement torque transmission mechanism Reverse C5 C3 Neutral C5 - First C5 C6 Second C5 C1 Third C1 C6 Fourth C1 C4 Fifth C1 C3 Sixth C1 C2 Seventh C2 C3 Eighth C2 C4 Ninth C2 C6

[0085] However, Mechanization Table 2100 describes other clutches that can be used for any given range. For example, in the fifth range, forces are applied to C1 and C3 to achieve this range. However, C4 and C6 are also available if the necessary fine-tuning system is triggered to allow fluid flow to the corresponding clutches. For example, if the fifth pressure control solenoid valve 324 is energized in the fifth range, the fifth fine-tuning valve 326 can be moved to allow pressure filling and apply force to C6. Thus, Mechanization Table 2100 describes the clutches under force, and the clutches that can be available depending on the valve position or the state of the solenoid valve. This is further described below regarding the hydraulic default range.

[0086] exist Figure 21 In the mechanized table 2100, it is worth noting that the first pressure control solenoid valve 308 can control C1 between a stressed and unstressed state, the second pressure control solenoid valve 312 can control C2 or C5 between a stressed and unstressed state, as discussed above, and the third pressure control solenoid valve 316 can control C3 between a stressed and unstressed state. Each of these three solenoid valves is a constant-pressure solenoid valve, and therefore, if power is cut off or no current is sent to these solenoid valves, each solenoid valve still outputs full pressure to the corresponding fine-tuning valve. If hydraulic pressure is received at the corresponding fine-tuning valve, force can be applied to the corresponding clutch or brake (C1, C2 / C5, and C3) through the solenoid valve that outputs full pressure.

[0087] Further, table 2100 further illustrates that fourth pressure control solenoid 320 can control C4 between force applied and no force applied, and fifth pressure control solenoid 324 can control C6 between force applied and no force applied. However, both of these solenoids are normally low solenoids, and thus output zero pressure when the solenoid is not receiving current. In the present embodiment, if power is lost and C4 or C6 is forced, the respective pressure control solenoid ceases to send pressure to the respective trim valve and does not force the clutch or brake. Thus, with respect to C4 and C6, if power is lost and no current is sent to their respective pressure control solenoids, both torque transfer mechanisms can be tripped from their force applied state to their no force applied state.

[0088] In Figure 21 The different hydraulic default ranges for each of the forward, neutral, and reverse ranges are further illustrated in mechanized table 2100. In Figure 3 In control system 300 and the multi-speed transmission that control system 300 controls, there are two clutch or brake combinations per range that are forced, except for neutral. In neutral, only one clutch or brake is forced. However, table 2100 identifies other clutches or brakes that can be forced. For example, in first range, C5 and C6 are normally forced. However, in the table, it is further illustrated that torque transfer mechanisms Cl, C3, and C4 can be forced if the controller is operable to energize or de-energize the necessary solenoids. The same applies for the other ranges, such as eighth range, where C2 and C4 are forced, but C3 and C6 can be used if the controller energizes the third and fifth pressure control solenoids.

[0089] As illustrated in the table, control system 300 includes a neutral default range, a low default range (i.e., fifth range), and a high default range (i.e., seventh range). In neutral, control system 300 can be optimally set such that if power is lost, C5 is not forced and C3 is forced to achieve the C3N default range (i.e., C3 neutral). As discussed above, C3 is controlled by third pressure control solenoid 316, and when power is lost, third pressure control solenoid 316 still outputs full pressure to advance third trim valve 318, and allows the hydraulic pressure at the trim valve to fill and force C3. This will be further illustrated with reference to Figures 15-17 The manner in which the low and high default ranges are achieved will also be illustrated below with reference to Figures 15-17 However, for the purposes of the present disclosure, control system 300 is capable of defaulting into three different conditions or ranges in the event of power loss, and each condition or range is capable of better protecting the transmission from damage.

[0090] In Figures 3-17 In the control schematic, the trim valves and shift valves are illustrated without further detail, i.e., without further detail regarding length and diameter. SeeFigure 18 which shows one non-limiting example of a valve 1800. In this example, the valve 1800 can be an example of the first shift valve 346. Here, the overall length of the valve 1800 has different sections and diameters (or widths). The valve 1800 can include a stem or body 1802. Further, along the length of the valve 1800, there are a first valve section 1804, a second valve section 1806, a third valve section 1808, a fourth valve section 1810, a fifth valve section 1812, and a sixth valve section 1814. In this example, the fourth valve section 1810 has a diameter Dl, which is larger than the diameters of the first, second, and third sections. Additionally, the fifth valve section 1812 has a diameter D2, which is larger than Dl, and thus, the diameter of the fifth valve section 1812 is larger than the diameters of the first, second, third, and fourth valve sections. Yet additionally, the overall diameter D3 of the sixth valve section 1814 is larger than the diameters Dl and D2. As such, the sixth valve section D3 is the largest diameter of the valve 1800.

[0091] In Figure 18 , the valve 1800 is also shown to include three interlocks or latches. An interlock or latch can refer to a hydraulic pressure that holds the valve in place, independent of the solenoid pressure. Thus, as long as the hydraulic pressure is available at the interlock or latch, the valve cannot move. This is particularly relevant to shift valves. Although not shown in this disclosure, each shift valve can be provided within a valve sleeve of a valve body or the like along with a return spring. The spring can have a spring force that counteracts the travel of the shift valve from its untravelled position to its travelled position. However, with the latches or interlocks, sufficient hydraulic pressure can act on the valve section to hold the valve in place even if the solenoid pressure to the head of the valve is removed. In Figure 18 , a first interlock 1816 is shown on the fourth valve section 1810, a second interlock 1818 is shown on the fifth valve section 1812, and a third interlock 1820 is shown on the sixth valve section 1814. Thus, on the first shift valve 346, there can be three interlocks.

[0092] With respect to the interlocks, the first shift valve can be referred to as a range valve. During operation, hydraulic fluid acting on one of the interlocks can allow the range valve to stay in a certain range. The same is true for the neutral. Further, the interlocks on the first shift valve allow the control system to default to the necessary default range, as shown in Figure 21 .

[0093] The interlocks are based on a force balance along the valve. If hydraulic pressure is acting on the first interlock 1816, and more specifically, on diameter Dl, this pressure can be greater than the spring force that counteracts the hydraulic pressure. The forces can be determined based on conventional manners, i.e., the amount of pressure multiplied by the area of the valve portion. With respect to the first shift valve 346, the interlocks can be based on which torque transmitting mechanism is engaged to maintain the valve in its stroked position. In the fifth range, for example, there can be no control pressure from the first shift solenoid, which in some cases will leave the first shift valve 346 unstroked. However, the hydraulic pressure acting on the third interlock 1820 can keep the valve in a stroked state and allow the clutch pressure to fill and force on CI. This is just one of several examples of interlocks keeping the shift valve in a desired position for a particular range. In another example, CI is forced on and hydraulic pressure flows to the first shift valve 346 and can act on the second interlock 1818 to maintain the valve in its stroked position.

[0094] Referring to Figure 19 which shows one example of a second shift valve 348. Here, a valve 1900 representing the second shift valve 348 can include a length that is partially bounded by a valve stem or body 1902, a first valve portion 1904, a second valve portion 1906, a third valve portion 1908, a fourth valve portion 1910, a fifth valve portion 1912, and a sixth valve portion 1914. As shown in Figure 19 , the first, second, and third valve portions can include a diameter D4, while the fourth, fifth, and sixth valve portions can include a diameter D5. Here, D5 is greater than D4, thereby forming or bounding an interlock 1916 on the larger valve portions. In addition, a second interlock 1918 is located at one end of the valve 1900. The second interlock 1918 can maintain the second shift valve 348 in an unstroked position by clutch pressure for C5. Thus, even if control pressure is provided at the opposite end of the second shift valve 348 by the first shift solenoid 330, the hydraulic pressure at the second interlock 1918 can be sufficient to keep the valve from stroking.

[0095] With respect to the first interlock 1916 on the valve 1900, this can be useful when operating in higher ranges (e.g., sixth-ninth ranges) and CI is forced on. As previously noted, the second shift valve 348 can dictate whether CI or C5 is forced on. In other words, this shift valve is multiplexed, which will be described below. However, in the seventh range Figure 12) the first shift solenoid 330 can supply control pressure to one end of the second shift valve 348 to move it to its advanced position. Hydraulic pressure filling and applying force to C2 can also flow between the third valve portion 1908 and the fourth valve portion 1910, and due to the first interlock 1916, the second shift valve 348 can be hydraulically held in place regardless of whether the first shift solenoid 330 sends control pressure. This is again due to the hydraulic pressure acting on the differential areas of the valve 1900 (due to force balance across the valve). Thus, the interlock can be used to establish a default range Figures 15-17 ), which is discussed further below.

[0096] As mentioned above, the second shift valve 348 can be multiplexed. However, first, in the control system 300 of Figure 3 , each clutch or brake is hydraulically filled and force applied to it. For Cl, C3, C4, and C6, there is a trim system for filling and applying force hydraulically to each torque transmitting mechanism. In a multiplexed system, a single trim system is used to hydraulically apply force to more than one torque transmitting mechanism. With respect to C2 and C5, the second shift valve 348, the second pressure control solenoid 312, the second trim valve 314, and the boost valve 354 can be used for hydraulic control. In one example, if the second shift valve 348 is not advanced (i.e., up-advanced), then C5 (i.e., reverse, neutral, first, and second ranges) can be hydraulically controlled. On the other hand, if the second shift valve 348 is advanced (i.e., down-advanced), then C2 (i.e., sixth-ninth ranges) can be hydraulically controlled. Thus, if hydraulic pressure is available at the second shift valve, then C2 or C5 can be hydraulically force applied based on the position of the shift valve.

[0097] With the second shift valve 348 acting as a multiplexed system, less hardware (such as trim solenoids and trim valves) is necessary for the control system. Furthermore, the multiplexed system effectively “locks out” or prevents both C2 and C5 from being force applied at the same time. This can be important, for example, to protect the integrity of the transmission from potential damage due to locking out the output. At higher speeds when C2 is force applied, there can be potential damage to the transmission if C5 is also force applied at the same time. Thus, the second shift valve 348 can only allow C2 or C5 to be hydraulically force applied, not the other.

[0098] Referring now to Figure 20 , which shows a representative valve 2000 for the third shift valve 350. The valve 2000 is just one example of the third shift valve 350, as it can be different in other examples. However, in Figure 20In this example, the valve 2000 can include a length defined by the valve stem or body 2002, the first valve portion 2004, the second valve portion 2006, the third valve 2008, the fourth valve portion 2010, and the fifth valve portion 2012. In this example, each valve portion has the same diameter or width. Thus, there is no interlock or latch formed with this valve 2000. However, in other embodiments, one or more of the valve portions can have different diameters or widths to form an interlock or latch.

[0099] In this disclosure, the third shift valve 350 can be referred to as a power valve. The power valve is capable of blocking hydraulic pressure from applying force to CI. It does so effectively to block the main pressure feed to the first pressure control trim system, e.g., the first trim valve 310. In the seventh range, for example, the third shift valve 350 is capable of blocking the main pressure from reaching the first trim valve 310 Figure 12 ). In Figure 12 the main pressure is supplied by the pressure source 302 and it can flow to the third shift valve 350. As noted above, the third shift valve 350 can not include any interlock or latch and thus its position can be controlled by the control pressure from the second shift solenoid 332. However, in Figure 12 the second shift solenoid 332 can be de-energized so that it does not output any control pressure. Without any control pressure acting on the third shift valve 350, the third shift valve 350 can not be stroked. In its un-stroked position, the main pressure from the pressure source 302 is blocked, e.g., by the second valve portion 2006. Thus, from Figure 12 and in the seventh range, CI is not applied force due to the third shift valve 350 blocking the pressure from reaching the first trim valve 310. In the eighth and ninth ranges, the same is true.

[0100] The third shift valve 350 is also capable of blocking hydraulic fluid flow to the second trim system, i.e., the second trim valve 314. In addition, the third shift valve 350 is also effective to block flow to the second shift valve 348. However, in the seventh range, for example, the interlock on the second shift valve 348 holds the valve in a position that is filled and applying force to C2. As will be discussed below, the second shift valve 348 and the third shift valve 350 can also be controlled so that hydraulic pressure is not fed to all three trim valves actuated by the high constant solenoid. If clutch pressure is fed to all three trim valves, one of CI, C3, and C2 or C5 will apply, thereby possibly damaging the transmission. The control system 300 thus controls the position and movement of the second and third shift valves to block flow from one or more of the trim valves to prevent damage to the transmission.

[0101] Another feature of the present disclosure is the control range valve, i.e., the first shift valve 346. The range valve is operably controlled by the shift-by-wire control system. In other words, a vehicle operator can press a button, turn a knob, trigger a switch, or some other operation to send an instruction to the controller to select a range of the transmission system. The controller, in turn, can energize one or more solenoids to electrically actuate the control system 300 to the desired range. Thus, in a shift-by-wire control system, there is no manual linkage for controlling the pawl, or similar, for manually controlling the transmission system to a range. In the present disclosure, the controller can thus control the position of the range valve (i.e., the first shift valve 346) in order to select a range or shift to a different range.

[0102] In alternative embodiments, the range valve can be replaced by a three- position manual valve that is manually actuated by a shift linkage. In other words, a cable or other linkage can be installed for manually controlling the transmission to the appropriate range.

[0103] Turning now to Figure 3 in detail, which shows the control system 300 operating in reverse. In other words, the controller has received a command from the operator to control the transmission in reverse by the shift-by-wire system, or the operator has controlled the shift linkage to control the transmission in reverse. Regardless, the primary pressure is supplied to the control system 300 by the pressure source 302. As shown in Figure 21 and described above, C3 is in mesh with C5 in reverse. To accomplish this, the primary pressure is fed to the third trim valve 318, and the controller energizes the third pressure control solenoid 316 to move the third trim valve 318 to its advanced position. In this way, hydraulic fluid is able to fill and apply force to C3 in reverse.

[0104] For C5, it is first noted that the first shift solenoid 330 is de-energized, and the second shift solenoid 332 is energized. Thus, the first and second shift valves are in their respective unadvanced positions, and the third shift valve 350 is in its advanced position (i.e., due to the second shift solenoid 332 controlling the third shift valve 350). With the third shift valve 350 in its advanced position, the primary pressure is able to flow through the third shift valve 350, and through the second shift valve 348, as shown in Figure 3 With the primary pressure flowing through the second shift valve 348, it flows directly to the second trim valve 314. The controller can energize the second pressure control solenoid 312 in order to move the second trim valve 314 to its advanced position, and with the primary pressure at the second trim valve 314, hydraulic fluid is able to flow through the second trim valve 314 and back through the second shift valve 348 to fill and apply force to C5.

[0105] Once C5 is forced, the C5 pressure flows back through the second shift valve 348, as shown in Figure 3The C5 pressure can flow and apply pressure against one end of the second shift valve 348 to maintain the valve in its position. In this example, a lock can be formed on one end of the second shift valve 348.

[0106] The C5 pressure also flows back to the boost valve 354 and can force or maintain the boost valve 354 in its unstroked position. The function and use of the boost valve will be further described below.

[0107] In reverse, the other torque transmitting mechanisms are not forced. First, the main pressure flows to the first shift valve 346, but is effectively blocked by the first shift valve 346 which is unstroked. The second shift valve 348 also blocks the main pressure through one of its valve sections. As a result, there is no main pressure fed to the first trim valve 310. With respect to C2, as we described earlier, the second shift valve 348 multiplexes and only allows force to be applied to one of C2 or C5. In reverse, the second shift valve 348 can be in its unstroked position such that force is only applied to C5.

[0108] With respect to C4 and C6, the controller does not send any current to the fourth pressure control solenoid 320 or the fifth pressure control solenoid 324, and thus the respective trim valves are not stroked. With respect to the fourth trim valve 322, it is in its unstroked position and thus no hydraulic fluid can be fed to C4. In addition, the second shift valve 348 blocks the main pressure from feeding to the fifth trim valve 326, and if there is even pressure fed to the fifth trim valve 326, the fifth pressure control solenoid 324 is de-energized. Thus, the fifth trim valve 326 is not stroked and no hydraulic fluid can be fed and force applied to C6. Figure 3 The main pressure flows to the fourth trim valve 322 as shown in

[0109] With the reverse described above and shown in Figure 3 The control system 300 is further able to control the transmission from reverse to neutral in the event of a power loss with the reverse. This is shown in Figure 15 In this embodiment, C3 remains forced and C5 is vented. During the power loss, the always low solenoids (i.e., the fourth pressure control solenoid 320 and the fifth pressure control solenoid 324) are de-energized and thus C4 and C6 cannot be fed and forced. In addition, the first shift solenoid 330 and the second shift solenoid 332 are de-energized and thus the first shift valve 346, the second shift valve 348, and the third shift valve 350 are unstroked. Finally, the always high pressure control solenoids 308, 312, and 316 output full pressure during the power loss.

[0110] As shown in Figure 15As shown in FIG. 3, the primary pressure is supplied from the fluid source 302 to the third trim valve 318, the fourth trim valve 322, the first shift valve 346, and the third shift valve 350. The hydraulic fluid is able to continue to fill and force C3 by the third pressure control solenoid 316 outputting full pressure to the third trim valve 318. Thus, from reverse to the default neutral, C3 remains forced. C4 and C6 remain unforced as they are always low solenoids. Even if the first and second pressure control solenoids are outputting full pressure to cause the first trim valve 310 and the second trim valve 314 to advance, the first shift valve 346 and the third shift valve 350 are not advanced and effectively block the primary pressure from flowing to either trim valve. Additionally, by the first and third shift valves not being advanced, there is no hydraulic fluid for the second shift valve 348 to feed from. Without any fluid passing through either of the shift valves or the second trim valve 314, C2 and C5 are not filled and forced. Thus, in the loss of power event of FIG. 3, only C3 is forced and the transmission defaults to the C3 neutral state. Figure 15

[0111] During the loss of power from reverse to the C3 neutral, C5 is vented. In one embodiment, C5 can be considered a large clutch or brake that requires a large amount of fluid to force it. At low temperatures, the viscosity of the fluid can be such that the fluid does not quickly drain from C5. The first drain path for C5 is through the second shift valve 348 and the second drain path is through the second trim valve 314. In both cases, the fluid travels a long distance to reach the drain outlet (identified in FIG. 3 as the small circle with the enclosed X). Due to its higher viscosity at low temperatures, it can be difficult to quickly vent C5 through the first or second drain paths. Figures 3-17

[0112] However, as shown in FIG. 4, a third and shorter drain path can be provided for more quickly venting C5. Here, a third drain path is defined from C5 through the third shift valve 350 and to the drain backfill valve 342 where the fluid is drained to the reservoir 206. When C5 is released, hydraulic fluid is able to flow through any of the three fluid paths to drain and the third drain path is shorter than the first and second drain paths, thereby allowing the fluid to drain more quickly at lower temperatures. Figure 15

[0113] Referring to FIG. 5, a fourth and even shorter drain path can be provided for more quickly venting C5. Here, a fourth drain path is defined from C5 through the third shift valve 350 and to the drain backfill valve 342 where the fluid is drained to the reservoir 206. When C5 is released, hydraulic fluid is able to flow through any of the four fluid paths to drain and the fourth drain path is shorter than the first, second, and third drain paths, thereby allowing the fluid to drain more quickly at lower temperatures. Figure 4 ​​​which shows the control system 300 controlling the transmission when in neutral or parked. In this illustrative embodiment, C5 is engaged, and the other torque transmitting mechanisms are disengaged. To get this setup, the primary pressure continues to be supplied by the pressure source 302. Here, the controller energizes the second pressure control solenoid 312 to move the second trim valve 314 to its stroked position. The other pressure control solenoids are de-energized, and thus CI, C3, C4, and C6 are disengaged. The first shift solenoid 330 is de-energized, and thus the first shift valve 346 and the second shift valve 348 are not stroked. However, the second shift solenoid 332 is energized, and controls the primary pressure feed to one end of the third shift valve 350 to move it to its stroked position.

[0114] The primary pressure feeds the third trim valve 318 and the fourth trim valve 322, but through each trim valve that is not stroked, there is no pressure to fill C3 or C4. Through the first shift valve 346, which is not stroked in Figure 4

[0115] With the third shift valve 350 stroked from the controlled primary pressure fed by the second shift solenoid 332, the primary pressure can flow through the third shift valve 350 to the second trim valve 314 through the second shift valve 348. In particular, when the second shift valve 348 is not stroked, hydraulic fluid can be able to flow between the first portion 1904 and the second portion 1906 of the valve. As the fluid flows to the second trim valve 314, the second pressure control solenoid 312 is energized by the controller to move the second trim valve 314 to its stroked position. As a result, fluid can flow back through the second shift valve 348 and fill and apply force to C5.

[0116] With the solenoids de-energized, the controller is not able to control any of the solenoids. As a result, when the transmission is in neutral, as shown in Figure 4 Figure 15 With the third shift valve 350 moved to its un-stroked position, as shown in ​​

[0117] As shown in Figure 15 The main pressure continues to flow to the third and fourth trim valves. With the third pressure control solenoid 316 outputting full pressure to move the third trim valve 318 to its stroked position, fluid is able to fill and apply force to C3. This is not the case for C4, as the fourth pressure control solenoid 320 remains de-energized and the fourth trim valve 322 thus blocks the main pressure from filling C4. As a result, when the transmission is in neutral or park and de-energized, C5 is vented and C3 is applied force, such that the control system 300 defaults to a C3 neutral state.

[0118] One feature of this default C3 neutral state is that the range valve (i.e., the first shift valve 346) is in its un-stroked position and blocks fluid flow to the first trim valve 308 and the fifth trim valve 326. Additionally, the third shift valve 350 is un-stroked and blocks fluid flow to the second trim valve 314. Thus, even if the first pressure control solenoid 308 and the second pressure control solenoid 312 output full pressure to their respective trim valves, the first shift valve 346 is set to block the supply of hydraulic fluid from filling Cl and C6, and the third shift valve 350 is set to block the supply of hydraulic fluid from filling C5. As a result, the transmission is effectively prevented from shifting into the reverse or forward range due to the position of the first shift valve 346 and the third shift valve 350.

[0119] Another aspect of the present disclosure is the ability to detect valve position and default range through pressure switches. With shift valves, it is necessary to be able to detect the position of each shift valve to ensure that hydraulic fluid is directed to the correct path and to prevent unwanted torque transfer mechanisms from being filled and forced. In the present disclosure, this is especially true in the case of the second shift valve that multiplexes and controls both C2 and C5. Each pressure switch in the control system 300 is able to be pressurized by the control main pressure and moved between a first position and a second position. Each pressure switch is in electrical communication with the controller to provide feedback to the controller based on the position of the switch. As will be described below, the pressure switches are able to communicate additional information to the controller including low or high gain and boost valve 354 position.

[0120] In the control system 300 of Figures 3-17 , the first pressure switch 356 is able to detect the position of the first shift valve 346, the second pressure switch 358 is able to detect the position of the second shift valve 348, and the third pressure switch 360 is able to detect the position of the third shift valve 350. The fourth pressure switch 362 is able to detect the position of the third trim valve 318, and thus whether C3 is engaged. If the transmission is operating in a steady state neutral with C5 applied force, and the fourth pressure switch 362 detects the third trim valve 318 moving from its un-stroked position to its stroked position (and thus, will apply force to C3), the controller can detect this movement through the fourth pressure switch 362.

[0121] In the present embodiment, the fourth pressure switch 362 can change state or position when the third trim valve 318 is moved to a position near the halfway point between fully stroked and fully un-stroked. In this example, the fourth pressure switch 362 can be vented when the third trim valve 318 is un-stroked. However, when the third trim valve 318 is moved to its stroked position, control pressure fills and pressurizes the fourth pressure switch 362, thereby sending a signal to the controller indicating this event. As noted above, reverse is achieved when C3 and C5 are pressurized. Thus, in the neutral range with C5 pressurized, the controller receives a message from the fourth pressure switch 362 that C3 will be pressurized immediately as the third trim valve 318 moves closer to its stroked position. If the controller determines that reverse is undesirable, it can vent C5 and default to the C3 neutral state to prevent reverse. Thus, the fourth pressure switch 362 provides good fault detection when operating in neutral.

[0122] The controller is also able to monitor the different pressure switches to determine if a particular valve is stroked. For example, if the first shift valve 346 is moved to its stroked position, the first pressure switch 356 can detect this movement and communicate it to the controller. In this way, the controller is better able to control the control system 300 and ensure that the proper range is selected based on operator input. This is especially true in the case of a line control shift system, whereby an operator can select a button to control the transmission from park to the first forward range. In this case, the controller is able to detect the shift in range by monitoring the pressure switches.

[0123] Another feature of the present disclosure is the use of a pressure switch with the multiplexing function of the second shift valve 348. As previously described, the second shift valve 348 is able to control whether C2 or C5 is engaged. If the second shift valve is un-stroked, C5 is engaged and C2 is vented. If the second shift valve 348 is stroked, C2 is engaged and C5 is vented. Depending on the position of the second shift valve 348, the second pressure switch 358 is either pressurized or vented. In one embodiment, the second pressure switch 358 is vented when the second shift valve 348 is un-stroked and pressurized when the second shift valve 348 is stroked. In an alternative embodiment, the second pressure switch 358 is pressurized when the second shift valve 348 is un-stroked and vented when the second shift valve 348 is stroked. Regardless, the second pressure switch 358 can change state between vented and pressurized when the second shift valve 348 reaches approximately the halfway position between the stroked and un-stroked positions. Furthermore, the controller is able to detect the position of the second shift valve 348 and whether C2 or C5 can be filled and pressurized based on whether the second pressure switch 358 is vented or pressurized.

[0124] Turning to Figure 5 which illustrates one embodiment of a control system 300 that controls the transmission in the first forward range. In this embodiment, the primary pressure is supplied to the system 300 by the pressure source 302. The controller can send current to the first shift solenoid 330 and the second shift solenoid 332 in order to move the first shift valve 346 and the third shift valve 350. The control primary pressure is fed to all three shift valves from both shift solenoids, but only the first shift valve 346 and the third shift valve 350 move to their advanced positions. When the control primary pressure is fed to the second shift valve 348, the second shift valve 348 does not move from its unadvanced position. As described above, C5 is forced in neutral, and in the process, hydraulic fluid flows from the second trim valve 314 through one end of the second shift valve 348 to fill and force C5. As the fluid flows through the second shift valve 348, it is able to hold or maintain the valve hydraulic pressure in this position. In other words, one of the aforementioned interlocks 1918 holds the valve in place even though the control primary pressure from the first shift solenoid 330 attempts to move the second shift valve 348. Thus, in this first forward range (or simply, first range), C5 remains forced from neutral.

[0125] The primary pressure flows to the third trim valve 318 and the fourth trim valve 322 according to its normal flow path. Here, the controller does not energize the third pressure control solenoid 316 or the fourth pressure control solenoid 320, and thus the respective trim valves block the feeding of primary pressure to C3 or C4. In the same manner, the primary pressure is fed to the first trim valve 310 through the shift valve, but the controller also does not energize the first pressure switch 308, and thus C1 cannot be forced because the first trim valve 310 blocks the primary pressure. Finally, the second shift valve 348 prevents fluid from filling and forcing C2 by the hydraulic fluid that forces C5 and maintains the second shift valve 348 in its unadvanced position. Thus, C1-C4 are not forced in the first range.

[0126] In Figure 5 the illustrative embodiment, the controller does send current to energize the fifth pressure control solenoid 324. In so doing, the fifth pressure control solenoid 324 is able to move the fifth trim valve 326 and the boost plug 328 to allow fluid to fill C6. Hydraulic fluid supplied by the pressure source 302 flows to the first shift valve 346, and through the first shift valve 346 that is moved to its advanced position, the fluid is able to flow to the fifth trim valve 326 and fill C6. Thus, C6 is forced in the first range.

[0127] As described above, the second pressure switch 358 can be in communication with the position of the second shift valve 348 with the controller. Thus, the controller can send current to the first and second shift solenoids and, based on feedback from the first pressure switch 356, the controller can detect movement of the first shift valve 346 to its travel position. However, when shifting from neutral to the first range, C5 remains forced and the second shift valve 348 does not move. For example, the controller can detect that the interlock acting on the second shift valve 348 is working properly as long as the second pressure switch 358 remains vented (assuming it is vented in neutral). In this way, the pressure switch can be in communication when the interlock is active.

[0128] Similarly, an interlock can exist on the other end of the second shift valve 348. Here, the interlock is not active in the first range, but it is active in the seventh, eighth, and ninth ranges. Control pressure fed from the third shift valve 350 acts on the top end of the second shift valve 348 to hydraulically hold the second shift valve 348 in its travel range. As such, the second pressure switch 358 can be pressurized by the valve in this position, and the controller can detect that the interlock is active based on the valve position.

[0129] In Figure 6 , the control system 30 is shown hydraulically operating the transmission in another embodiment of the first range. In Figure 5 , the TCC solenoid 304 is de-energized so that the primary pressure is blocked by the TCC trim valve 306. In this embodiment, there is no lockup pressure supplied to the torque converter 202 of the transmission system 200. However, in Figure 6 , the controller can send current according to any known means for energizing the TCC solenoid 304 and moving the TCC trim valve 306 to its travel position. As shown in Figure 6 , the lockup clutch pressure can be fed from the TCC trim valve 306 to the converter flow 214. Fluid can flow from the converter flow 214, through the converter in path 222, to force the lockup clutch of the torque converter 202. The manner and operation of the lockup clutch can be according to any known means. Further, when the controller energizes or de-energizes the TCC solenoid 304, it can be according to any known algorithm or process based on speed, torque, range, etc. It should be noted that in Figure 6 , the manner of forcing C5 and C6 is substantially the same.

[0130] With the first range de-energized, no current is sent to energize the fifth pressure control solenoid 324, the first shift solenoid 330, or the second shift solenoid 332. As a result, the fifth trim valve 326 is not traveled and blocks the fluid path to C6. C6 is thus vented. This is also shown in Figure 16In the second shift solenoid 332 is de-energized, the third shift valve 350 is not stroked and blocks the main pressure feed to the second trim valve 314. As a result, hydraulic fluid is no longer supplied to C5 and C5 vents. Thus, no fluid is supplied to C5 or C6, both of which were previously force applied in the first range.

[0131] However, as previously described, the first and third pressure control solenoids are normally high solenoids that output full pressure in the de-energized event. With the main pressure feed to the third trim valve 318, when de-energized, C3 is filled and force applied. Also, with the first pressure control solenoid 304 outputting pressure to the first trim valve 306, main pressure is able to fill and force apply to CI through the first shift valve 346. Thus, when the control system 300 is operating in the first range and de-energized, the control system 300 defaults to the fifth range by venting C5 and C6 and force applying CI and C3.

[0132] In another aspect of the disclosure, the control system 300 is able to control gain actuation through the boost plug 328. In this aspect, the control system 300 is able to provide a low clutch control gain in the ninth range and a high clutch control gain in the third range. To do so, the boost plug 328 can be operably controlled to adjust the gain.

[0133] Prior to the introduction of C6, gain control can be relevant when the torque transmitting mechanism can require different pressures for different ranges. For example, in one high range, the mechanism can only require 80 psi, but in a lower range, the same mechanism can require 230 psi to maintain torque. To achieve these different pressures, the gain can be adjusted on the clutch trim system. Further, a pressure switch can be used to detect the high or low gain and communicate it to the controller.

[0134] C6 is force applied in the first, third, and ninth ranges by the fifth pressure control solenoid 324 and the fifth trim valve 326. In the first range, C6 can require, for example, up to 250 psi to maintain torque, while in the ninth range, C6 can only require approximately 80 psi. These pressures are provided as examples only and can vary in different embodiments. Thus, these pressures are not limiting the scope of this aspect of the disclosure.

[0135] In the first range, the torque can be much greater than in the ninth range. In the ninth range, controllability and shift quality can be important. Thus, in the first range, the gain can be set at 2.78 to achieve higher clutch pressures, and in the ninth range, the gain can be set at 1.6. Again, these gain values are non-limiting and are provided only as examples of low and high gain values. Gain adjustments on the trim valve are possible due to the differential areas on one or more portions of the valve. This is partially described above with respect to the shift valve and interlock.

[0136] Further employing this example, assume that the pressure control solenoid is capable of outputting 1000 kPa. At low range, the 2.78 gain allows the trim system to output up to 2780 kPa. Similarly, at higher range, the 1.6 gain allows the trim system to output up to 1600 kPa. Thus, there is a relationship between the output pressure of the solenoid (typically dictated by the control pressure or control main pressure) and the actual clutch pressure. Shift quality is better achieved at lower clutch pressures, but torque requirements at lower range can require larger clutch pressures to reduce or prevent clutch slip.

[0137] In addition to the above, the pressure switches can also communicate the gain level to the controller. With respect to the fifth trim valve 326, the second pressure switch 358 is capable of detecting its position. In the first range ( Figure 5 and 6 ) and the third range ( Figure 8 ), the output pressure from the fifth pressure control solenoid 324 forces the fifth trim valve 326 and the boost plug 328 in the down or travel position, where "down" is simply relative to the way the valve and plug are shown in the figures. In the Figure 8 , for example, there is no control main pressure to the second pressure switch 358. Based on this, the controller is able to detect that the fifth trim system is set at its high gain level.

[0138] However, in the ninth range ( Figure 14 ), the control main pressure is fed to pressurize the second pressure switch 358. The same control main pressure is fed to the boost plug 328, where hydraulic fluid is able to flow through the passage 344 defined in the boost plug 328. As a result, the hydraulic fluid separates the boost plug 328 from the fifth trim valve 326 and moves the plug 328 toward the fifth pressure control solenoid 324. In this condition or state, the trim system is at the low gain value, and the second pressure switch 358 detects this value and communicates it to the controller.

[0139] The high / low gain actuation of the fifth fine-tuning system allows for lower clutch pressure control in the ninth range to improve shift quality and controllability, and higher clutch pressure control in the first and third ranges to reduce or prevent clutch slippage. Due to the higher gain, this further allows for complete engine torque clutch control during shifts from neutral to the first range, without requiring any additional hardware or actuators for detecting the gain setting. The second pressure switch 358 is therefore able to detect the position of the second shift valve 348 and the gain setting of the fifth fine-tuning valve 326.

[0140] See Figure 7 This indicates the second forward gear range, or simply, the second range. Here, the control system 300 is able to selectively control the filling of hydraulic fluid and apply force to C1 and C5. In the first range, force is applied to C5 and C6 to shift or change gears to the second range, bleed C6 and apply force to C1.

[0141] To shift to the second range, the controller can energize the second shift solenoid valve 332, which pressurizes and propels the third shift valve 350. The first shift solenoid valve 330 may not receive current in the second range and therefore does not feed control main pressure into the head of either the first or second shift valve. However, this timing may vary depending on the embodiment. For example, the controller may delay de-energizing the first shift solenoid valve 330 until the high-speed shift from the first range to the second range is complete. Once the shift is complete, the controller can then de-energize the first shift solenoid valve 300. Therefore, when Figures 3-17 An illustrative embodiment may illustrate that, when one of the two shift solenoid valves is energized or de-energized, the controller can control the timing of when the corresponding solenoid valve is energized and de-energized to allow various gear shifts of the transmission to be completed. Software, control algorithms, calibration methods, instructions, tables, graphs, etc., may be stored in the memory unit 144 of the controller 142 and executed in any known manner to control the timing of sending current to any of the solenoid valves in the control system 300.

[0142] In any case, within the second range, the controller energizes the first pressure control solenoid valve 308 and the second pressure control solenoid valve 312 to move the first fine-tuning valve 310 and the second fine-tuning valve 314 to their respective travel positions. The third pressure control solenoid valve 316, the fourth pressure control solenoid valve 320, and the fifth pressure control solenoid valve 324 are de-energized, and their respective fine-tuning valves are in their non-travel positions to prevent hydraulic fluid from filling and applying force to C3, C4, and C6, respectively.

[0143] For hydraulic fluid flowing through the control system 300, the main pressure is again fed into the first shift valve 346 and the third shift valve 350 by the pressure source 302, as in Figure 7The hydraulic fluid flows through the third shift valve 350 in the same manner as in the first range. In doing so, it can flow through the second shift valve 348 (e.g., between the first valve portion 1904 and the second valve portion 1906) to the second trim valve 314. With the second trim valve 314 in its travel position, the hydraulic fluid can be trimmed to the desired clutch pressure and redirected back to the second shift valve 348. As the fluid flows back to the second shift valve 348, it can flow between the fourth valve portion 1910 and the fifth valve portion 1912 as it fills and applies force to C5. When the hydraulic fluid fills and applies force to C5, it flows back through the second shift valve 348 and, in particular, on the bottom side of the sixth valve portion 1918 to keep the second shift valve untraveled as it flows to the bottom side of the boost valve 354 to keep the boost valve 354 untraveled. The operation of the boost valve 354 is described further below. The hydraulic fluid acting on the bottom side of the sixth valve portion 1918 of the second shift valve 348 can act as an interlock 1918.

[0144] To fill CI, the first shift valve 346 is in its travel position, similar to its position in the first range. As the liquid is fed to the first trim valve 310, hydraulic fluid from the source 302 is thus able to flow into the first shift valve 346 (e.g., between the second valve portion 1806 and the third valve portion 1808) and through the second shift valve 348 (e.g., between the second valve portion 1906 and the third valve portion 1908). With the first trim valve 310 traveled by the first pressure control solenoid 308, the hydraulic fluid is able to fill and apply force to CI. As the fluid applies force to CI, the hydraulic fluid feeds back to the first shift valve 346. As it does, it can flow between the fifth valve portion 1812 and the sixth valve portion 1814 and form an interlock 1820 to maintain the first shift valve 346 in its travel position.

[0145] In the event of a system power loss, the normally low solenoids (i.e., solenoids 320 and 324) are de-energized and output zero pressure, and the normally high solenoids (i.e., solenoids 308, 312, and 316) are de-energized but still output full pressure. As a result, the primary pressure is still fed to the third trim valve 318, and with it moved to its travel position by the third pressure control solenoid 316, the hydraulic fluid is able to fill and apply force to C3.

[0146] During the power loss, the first shift solenoid 330 and the second shift solenoid 332 are de-energized and thus move the third shift valve 350 to its untraveled position. In effect, the primary pressure is now blocked by the third shift valve 350, as in Figure 16As shown, and fluid cannot flow to the second shift valve 348 and the second trim valve 314. As a result, C5 is vented through either of its previously described venting paths. C1 remains forced when hydraulic fluid flows from the source 302 through the first and second shift valves to the first trim valve 310. Thus, C1 and C3 are forced in the power off event to achieve the fifth range. C2, C4, C5, and C6 are not forced in this case.

[0147] As described above, the third shift valve 350 is used to block hydraulic fluid feed to the second trim valve 314, and thus neither C2 nor C5 can be forced. Although primary pressure can be fed to the fourth and fifth trim valves, their corresponding normally low solenoids are de-energized and thus output zero pressure. As a result, the fourth trim valve 322 blocks fluid from filling C4, and the fifth trim valve 326 blocks fluid from filling C6.

[0148] Referring to Figure 9 , the control system 300 can operatively control the transmission in a third forward range (or simply, third range). In the third range, C1 and C6 are forced. Primary pressure is supplied by the pressure source 302 to the same flow paths in the system 300 as described above. The controller can energize the first pressure control solenoid 308 and the fifth pressure control solenoid 324. As a result, the first pressure control solenoid 308 outputs pressure to move the first trim valve 310 to its run position. Likewise, the fifth pressure control solenoid 324 outputs pressure to move the fifth trim valve 326 to its run position. The second pressure control solenoid 312, the third pressure control solenoid 316, and the fourth pressure control solenoid 320 are de-energized, and thus their corresponding trim valves are set in their un-run positions.

[0149] Primary pressure is blocked by the third trim valve 318 and the fourth trim valve 322, and pressure thus cannot fill and force C3 and C4, respectively. The first shift solenoid 330 and the second shift solenoid 332 are also de-energized in the third range, and thus the third shift valve 350 is un-run. With the third shift valve 350 un-run, primary pressure cannot flow to the second trim system, and C2 and C5 are thus disengaged.

[0150] Primary pressure does flow into the first shift valve 346 and the second shift valve 348. As a result, through the run first trim valve, hydraulic fluid can flow through the first and second trim valves and feed C1. If the transmission is upshifting from the second range to the third range, C1 is already filled and forced. Hydraulic fluid from C1 backfills the first shift valve 346, and the differential area acting on the first shift valve 346 to create a lockout and maintain the run state of the valve.

[0151] Hydraulic fluid can also be fed to the fifth trim valve 326 from the first shift valve 346. With the fifth trim valve 326 moved to its travel position, fluid can fill and apply force to C6. Thus, in the third range, Cl and C6 are applied.

[0152] In the event of a controller power loss, the control system 300 is configured to control the transmission to the fifth range with Cl and C3 forced. In so doing, no current is sent by the controller to any of the solenoids. Thus, the normally low pressure control solenoids and the first and second shift valves are de-energized and output zero pressure. When the fifth trim valve 326 is not traveled, C6 is thus vented. C4 is likewise left unfilled with the fourth trim valve 322 blocking the main pressure. Since the second shift solenoid 332 is de-energized, the third shift valve 350 is set in its un-traveled position thereby blocking hydraulic fluid flow to the second trim valve 314. Even if the second pressure control solenoid 312 outputs full pressure in the power loss event, hydraulic fluid is blocked by the third shift valve 350 and neither C2 nor C5 can be forced.

[0153] In the third range, Cl is applied and the hydraulic fluid fed to Cl is further fed back to the first shift valve 346 and keeps it in the traveled position based on the interlock formed there. The first trim valve 310 remains traveled since the first pressure control solenoid 308 outputs full pressure and Cl is thus kept forced. Further, the third pressure control solenoid 316 outputs full pressure in the power loss condition thereby moving the third trim valve 318 to its traveled position. Since the main pressure is fed directly to the third trim system, hydraulic fluid is able to fill and apply force to C3. As a result, in the power loss condition, Cl and C3 are applied and the control system 300 defaults to the fifth range.

[0154] Referring to Figure 9 illustrates the control system 300 in an embodiment of controlling the transmission in the fourth forward range or fourth range. In the fourth range, Cl and C4 are applied. To do so, the controller can energize the first pressure control solenoid 308 and the fourth pressure control solenoid 320. The first pressure control solenoid 308 outputs pressure to move the first trim valve 310 to its traveled position and the fourth pressure control solenoid 320 outputs pressure to move the fourth trim valve 322 to its traveled position. The other pressure control solenoids and both shift solenoids are de-energized. Thus, C3 and C6 are not applied since the third trim valve 318 and the fifth trim valve 326 are not traveled and block fluid from filling either clutch. Further, with the second shift solenoid 332 de-energized, the third shift valve 350 is not traveled which blocks the main pressure from feeding the second trim system. As a result, neither C2 nor C5 can be forced in the fourth range.

[0155] The primary pressure is provided by the pressure source 302 and fed directly into the fourth trim system as shown in Figure 16 by the fourth trim valve 322 in its travel position. In addition, while the first shift solenoid 330 is de-energized, pressure is applied to Cl through hydraulic fluid flowing through the first shift valve and the second shift valve to the first trim system. Through the filled Cl, hydraulic fluid flows back to the first shift valve 346 and the differential area on the first shift valve 346 (e.g., between valve portions 1812 and 1814) to create a lockup 1820 and maintain the shift valve in its travel position. Thus, Cl and C4 are applied pressure in the fourth range.

[0156] In the de-energized state of the controller, when the controller is unable to send current to energize the fourth pressure control solenoid 320, vent C4. Since the fourth pressure control solenoid 320 can be a normally low solenoid, when it is de-energized, it outputs zero pressure to the trim valve. Thus, the fourth trim valve 322 is not traveled and blocks hydraulic fluid from filling C4. Similarly, since the fifth trim valve 326 is not traveled and blocks fluid, C6 remains unapplied.

[0157] Similar to the first, second, and third ranges described above, the first and second shift solenoids are de-energized, leaving the third shift valve 350 in its untraveled position. As a result, hydraulic fluid is blocked by the third shift valve 350 and cannot feed into the second trim system. Thus, C2 and C5 are not applied pressure in the de-energized state.

[0158] Additionally, the third pressure control solenoid 316 is energized and outputs full pressure in the de-energized state. This moves the third trim valve 318 to its travel position and since the primary pressure is fed directly to the third trim system, fluid is able to fill and apply pressure to C3.

[0159] Cl is continuously fed with hydraulic fluid to remain applied during the de-energized state. Even though the first shift valve 346 does not receive the controlled primary pressure from the first shift solenoid 330, the pressure that fills and applies pressure to Cl flows back and acts on the differential area of the first shift valve 346 to create a lockup 1820 and maintain the first shift valve 346 in its travel position. As a result, when the control system 300 is operating in the fourth range and is de-energized, the control system 300 defaults to the fifth range (see Figure 10 ) by the applied Cl and C3.

[0160] In the de-energized state of the controller, when the controller is unable to send current to energize the fourth pressure control solenoid 320, vent C4. Since the fourth pressure control solenoid 320 can be a normally low solenoid, when it is de-energized, it outputs zero pressure to the trim valve. Thus, the fourth trim valve 322 is not traveled and blocks hydraulic fluid from filling C4. Similarly, since the fifth trim valve 326 is not traveled and blocks fluid, C6 remains unapplied. Figure 10In the middle, the control system 300 is shown in another embodiment where it is operable to control the transmission in a fifth forward range or fifth range. As described previously in several of the above embodiments, the fifth range can be obtained by applying force to CI and C3. The fifth range also happens to be the default range during power down when the control system 300 is operable to control the transmission in the first, second, third, and fourth ranges. Thus, for the purposes of this disclosure, the fifth range can also be referred to as the low range default. When power is down and the transmission is in reverse or neutral, the control system 300 can operate differently and is described above in this regard where the control system 300 defaults to the C3 neutral state. Here, in the lower forward ranges (i.e., the first through fifth ranges), the control system 300 defaults to the fifth range in the event of a power down. It should be noted that other default ranges can be possible and only the fifth range is illustrated and described herein as one such embodiment.

[0161] To operably control the transmission in the fifth range, the controller can energize the first pressure control solenoid 308 and the third pressure control solenoid 316. In so doing, each solenoid actuates and moves the first trim valve 310 and the third trim valve 318 to their respective on positions. The main pressure is supplied directly to the third and fourth trim systems by the pressure source 302 as shown in Figure 10 Through the third trim valve 318 in its on position, hydraulic fluid is able to fill and apply force to C3. On the other hand, the fourth trim valve 322 is in its off position thereby blocking fluid from filling C4. Similarly, the fifth trim valve is off thereby blocking fluid from filling and applying force to C6.

[0162] With the first and second shift solenoids de-energized in the fifth range, the control main pressure is not supplied to the head end of any of the three shift valves. As a result, the third shift valve 350 is off and blocks the supply of hydraulic fluid to the second trim system. Since no hydraulic fluid is able to flow through the third shift valve 350, CI and C5 are not applied.

[0163] CI is applied in the fifth range and is done so by the hydraulic fluid flowing through the first and second shift valves before feeding into the first trim system. With the first trim valve 310 in its on position, hydraulic fluid is able to fill and apply force to CI. The CI pressure (as shown in Figure 11 may flow back to the first shift valve 346 as is the case in the second, third, and fourth ranges. Here, the C5 pressure acts on the differential area (e.g., the sixth valve portion 1814) on the first shift valve 346 to form the interlock 1820 which hydraulically holds or maintains the first shift valve 346 in its on position.

[0164] Unlike the forward ranges described previously, when the transmission is operating in the fifth range, the same two torque transmitting mechanisms (i.e., CI and C3) remain forced when power is lost and the controller is unable to send current to either of the solenoids in the control system 300. In other words, when the transmission is not operating in the fifth range and power is lost, the default is the fifth range and thus there is no shift to another range. In the power loss condition, C4 and C6 remain unforced because the constant low fourth pressure control solenoid 320 and the constant low fifth pressure control solenoid 324 output zero pressure, and the corresponding trim valves remain unstroked to block hydraulic fluid from filling C4 and C6. In addition, the second shift solenoid 332 is de-energized, thereby causing the third shift valve 350 to be unstroked. When the third shift valve 350 is unstroked, hydraulic fluid cannot flow to the second trim system and fill C2 or C5. Thus, C2 and C5 are not forced in the power loss condition.

[0165] The constant high pressure control solenoids can output full pressure in the power loss condition. In view of this, the first pressure control solenoid 308 and the third pressure control solenoid 316 output full pressure, causing the first trim valve 310 and the third trim valve 318 to be set in their stroked positions. This allows hydraulic fluid to fill and force CI and C3 in the same manner as in the steady state fifth range described above.

[0166] In the present disclosure, there can be three default ranges to which the control system 300 defaults when power is lost. The first default range is the C3 neutral range, and as described above, this range is selected when the transmission is operating in reverse or neutral prior to power loss. The second default range is the fifth range in which CI and C3 are forced, and this occurs when the transmission is in the first, second, third, fourth, and fifth ranges. The third default range is the seventh range, and this occurs during power loss when the transmission is operating in the sixth, seventh, eighth, or ninth ranges. These latter forward ranges and the third default range will be described below. However, it should be understood that these default ranges apply to the illustrative embodiments provided herein. Other embodiments of the control system can default to other ranges. For example, there can be fewer than three default ranges, or in some examples, there can be more than four default ranges. Thus, this principle and teaching of the present disclosure is not intended to be limited to a certain specific default range or any number of default ranges.

[0167] Turning to Figure 17, the control system 300 is operable to control the transmission in the sixth forward range or sixth range. Here, the second shift valve 348 is actuated to its run position to allow C2 to fill and force. Also, C1 is forced in the sixth range. For C1, the controller can energize the first pressure control solenoid 308, which moves the first trim valve 310 to its run position. Also, the second pressure control solenoid 312 can be energized, thereby moving the second trim valve 314 to its run position. Meanwhile, the third pressure control solenoid 316, the fourth pressure control solenoid 320, and the fifth pressure control solenoid 324 are de-energized. As a result, hydraulic fluid is blocked by the third trim valve 318, the fourth trim valve 322, and the fifth trim valve 326, which effectively prevents C3, C4, and C6 from filling and forcing.

[0168] In this embodiment, the first and second shift solenoids are energized. As shown, the control main pressure is fed from the control main filter 336 to the first shift solenoid 330 and the second shift solenoid 332. Next, the control main pressure is fed to the head of the first shift valve 346, the second shift valve 348, and the third shift valve 350. All three shift valves are thereby moved to their run positions. Through the third shift valve 350 in its run position, the main pressure is fed through the shift valves as shown in Figure 11

[0169] In the same manner, hydraulic fluid from the pressure source 302 can flow directly to the first shift valve 346. Through the run first shift valve 346, fluid can flow to the second shift valve 348 and here to the second trim system. Through the second trim valve 314 in its run position, hydraulic fluid can flow through the second trim valve 314 and back to the second shift valve 348 and here fill and force C2. The C2 pressure further flows to the first shift valve 346 and acts on another differential area (e.g., between the fourth valve portion 1810 and the fifth valve portion 1812) of the first shift valve 346 to create another interlock 1818 on the first shift valve 346. Thus, in the sixth range, C1 and C2 are forced.

[0170] When hydraulic fluid flows to the second trim system and the second trim valve 314 is in its run position, hydraulic fluid can flow to the boost valve 354. The boost valve 354 can be used to "boost" or increase clutch pressure to allow the torque transfer mechanism to handle high torque operating modes. In Figure 7 ​In the illustrative embodiment, C2 is forced to encompass the highest torque mode of operation, while C5 can be designed such that it is not capable of handling such torque modes. C5 can be damaged due to compression fracture of the elevated pressure, and thus the control system 300 can be designed to prevent the boost valve 354 from actuating while engaging C5. In effect, whether the boost valve 354 is forced is a form of gain control of the second trim system, which is different from the aforementioned form of gain control of the fifth trim system.

[0171] In at least one example, it is desirable to limit the C5 pressure to be lower than the main pressure, while it is desirable for the C2 pressure to be approximately equivalent to the main pressure in at least one forward range. In another example, the C2 and C5 pressures can be less than the main pressure, but the C2 pressure is capable of being greater than the C5 pressure when the boost valve is actuated. In yet another example, the boost valve is actuated (or stroked) when C2 is forced, and the boost valve is de-actuated (or not stroked) when C5 is forced.

[0172] With the lower C5 pressure, the control system 300 is able to better provide improved shift quality and controllability. Additionally, the second pressure control solenoid 312 and the second trim valve 314 are able to further trim the C5 pressure if necessary. Thus, with the un-stroked boost valve 354, the C5 pressure is more controllable. However, as shown in Figure 11 As shown in, there is no solenoid for independent control of the movement of the boost valve 354. Thus, in the illustrative embodiment, the C5 pressure can be used as a blocking feature or mechanism to prevent the boost valve 354 from moving to its stroked position when C5 is forced. For example, in the second range, the main pressure is fed to the second trim system through the second and third shift valves. Hydraulic fluid flows through the second trim valve 314 and back to the second shift valve 348, and fills and forces C5 at this point. Once C5 is filled, fluid is able to flow back to the second trim system, and it flows to the bottom side of the boost valve 354. The C5 pressure thus pushes or forces the boost valve 354 to remain in its un-stroked position, thereby limiting the pressure of C5. The blocking feature or mechanism of the C5 pressure acting on the boost valve 354 is similar to a lockout, except here it hydraulically holds or maintains the boost valve 354 from moving to its stroked position. In contrast, the lockout as described herein is a hydraulic pressure that hydraulically holds or maintains the valve in its stroked position and prevents it from moving to its un-stroked position.

[0173] The C5 pressure can be reduced and maintained below the main pressure by the pressure boost valve 354 held by hydraulic pressure from being moved to its travel position. In one embodiment, the second pressure control solenoid 312 output can be limited to be higher than any pressure that controls the main pressure. The second trim valve 314 can have a gain associated with it such that the C5 pressure can be greater than the control main pressure. For example, if the gain is 1.25 and the control main pressure is 1000 kPa, then the C5 pressure can be 1250 kPa. The gain can be a function of differential areas on the second trim valve 314.

[0174] In the Figure 17 , the pressure boost valve 354 can be active and the C2 pressure can be approximately the main pressure. Here, when the main pressure is fed to the second trim system and fluid flows through the second trim valve 314, it also flows to the pressure boost valve 354. The flow to the pressure boost valve 354 causes the pressure boost valve 354 to move to its travel position. Further, by the C5 being stressed, there is no hydraulic fluid supplied to the bottom side of the pressure boost valve 354. The pressure boost valve 354 is thus able to move to its travel position and allow the increased C2 pressure. With the second trim valve 314, the same gain is obtained, but by the now-traveling pressure boost valve 354, the second trim valve 314 can even move further to a fully-travel position, for example, such that the main pressure is fed to C2. In effect, with the pressure boost valve 354 in active, the second trim valve 314 is able to have a further travel such that the main pressure is fed to C2. By contrast, with the C5 stressed, the second trim valve 314 is caused to travel, but to a much smaller extent, because the pressure boost valve 354 is not in an active state.

[0175] The tolerance in the second trim system can be provided by the limit on the second pressure control solenoid 312 or other tolerances within the main and control main circuits.

[0176] Before returning to the sixth range, it is further shown here that a second shift valve 348 can be provided to limit or prevent C2 and C5 from being stressed at the same time. In effect, this provides a failsafe mode protection by only allowing one of the two torque transmitting mechanisms to be stressed at a time.

[0177] In the sixth range, the control system 300 operably controls the transmission by the stressed Cl and C2. In the event of a power loss, the controller can not be able to send current to either of the solenoids. As shown in Figure 17 , when operating in the sixth range, in the event of a power loss, another default range can be provided. In this case, the first shift solenoid 330 and the second shift solenoid 332 are both de-energized. Thus, the third shift valve 350 moves to its un-travel position and blocks hydraulic fluid from flowing to Cl. In effect, the third shift valve 350 blocks fluid from reaching the first trim system and thus is not able to stress Cl.

[0178] When de-energized, the normally low fourth pressure control solenoid 320 and the fifth pressure control solenoid 324 can be de-energized, and thus neither solenoid outputs any pressure. As a result, the fourth and fifth trim valves are in their un-stroked positions and block the primary pressure feed to C4 or C6. Thus, as described herein, when operating in the sixth range and de-energized, C1, C4, C5, and C6 are not forced. C2 and C3 are thus forced in the high default range corresponding to the seventh range.

[0179] Since the primary pressure is fed directly to the third trim system as shown in Figure 18 , C3 is forced in this default range. Further, the third pressure control solenoid 316 can be a normally high solenoid, and thus outputs full pressure when de-energized. In so doing, the third trim valve 318 is actuated to its stroked position, thereby allowing hydraulic fluid to fill and force C3.

[0180] As described above, C2 is forced in the sixth range. The C2 pressure can create a lockout on both the first shift valve 346 and the second shift valve 348 in the sixth range. For example, referring to Figure 17 and 19 , the C2 pressure can create a lockout 1818 on the first shift valve 346 and another lockout 1916 on the second shift valve 348. Thus, even when the first shift solenoid 330 is de-energized and the control of the primary pressure is cut off, the C2 pressure can still hold the first and second shift valves in their stroked positions due to the lockouts in the high default range. Since the shift valve 348 is latched in the stroked position, the primary feed to C5 is blocked.

[0181] As also shown in Figure 12 , the boost valve 354 can be fully stroked so that the C2 pressure can be approximately equal to the primary pressure. The second trim system can adjust the C2 pressure as needed, but notably, the second trim valve 312 and the boost valve 354 are in their stroked positions.

[0182] Referring now to Figure 12 , a control system 300 is shown that operably controls the transmission in a seventh forward range (i.e., the seventh range). In the seventh range, C2 and C3 are forced as described above. In Figure 12 the normal or steady state seventh range, the controller can energize the second pressure control solenoid 312 and the third pressure control solenoid 316. Further, the first pressure control solenoid 308, the fourth pressure control solenoid 320, and the fifth pressure control solenoid 324 are de-energized. The controller further energizes the first shift solenoid 330, but de-energizes the second shift solenoid 332.

[0183] Hydraulic fluid can be fed to the control system 300 from a fluid pressure source 302, which as mentioned above, can be supplied by the hydraulic pump 204 of the transmission system 200. From the pressure source 302, which can be further referred to as the main pressure line of the control system 300, hydraulic fluid can be fed directly to the first shift valve 346, the third shift valve 350, the third trim system, and the fourth trim system. With the third pressure control solenoid 316 energized, the third trim valve 318 can be moved to its stroked or open position to allow hydraulic fluid to fill and apply hydraulic pressure to C3.

[0184] With the first, fourth, and fifth trim systems de-energized, the respective trim valves can block hydraulic fluid from filling Cl, C4, and C6. However, because the second shift solenoid 332 is de-energized, hydraulic fluid can be blocked upstream through the third shift valve 350 in its un-stroked position through Cl.

[0185] With the first shift solenoid 330 energized, control main pressure can be fed to the head of each of the first and second shift valves, thereby moving both shift valves to their stroked positions. The main pressure can be fed directly from the pressure source 302 to the first shift valve. With the first shift valve 346 stroked, hydraulic fluid can flow through the first shift valve 346 and the second shift valve 348 to the second trim system. Because the second pressure control solenoid 312 is energized, the second trim valve 314 can be in its stroked position, and thus hydraulic fluid is able to flow through the second trim system, back to the second shift valve 348, and fill and apply hydraulic pressure to C2. In addition, the hydraulic fluid flowing through the second trim valve further flows to the boost valve 354 and causes the boost valve 354 to stroke to its stroked position. With C5 vented, there is no hydraulic pressure opposing the movement of the boost valve 354 to its stroked position. As a result, the C2 pressure can increase or boost to approximately the main pressure.

[0186] As also shown in Figure 17 C2 pressure flows through the first shift valve 346 and the second shift valve 348 and acts on the differential areas or lands of both valves. In effect, the C2 pressure acting on these differential areas creates a lock-up on both valves to hold them in place. Because control pressure is still fed to the head of each of the first and second shift valves, the lock-up can be unnecessary in the seventh range, but the C2 pressure fills and applies hydraulic pressure to the differential areas on both valves.

[0187] Even in the event of a power outage, the control system 300 defaults to the seventh range. Therefore, when the transmission is in the seventh range and power is off, the transmission does not shift gears and instead remains in the seventh range where forces are applied to C2 and C3. The normally high pressure control solenoid valve defaults to full output pressure, and the normally low pressure control solenoid valve defaults to zero output pressure. Therefore, since the fourth and fifth fine-tuning valves block hydraulic fluid, forces are not applied to C4 and C6 in the event of a power outage. Furthermore, the first and second shift solenoid valves are de-energized, and thus the third shift valve 350 is in its non-operating position. Therefore, the third shift valve 350 blocks hydraulic fluid from filling C1.

[0188] In the event of a power outage, the second pressure control solenoid valve 312 and the third pressure control solenoid valve 316 output full pressure. Since the main pressure is directly fed into the third fine-tuning system, hydraulic fluid can fill and apply force to C3. Furthermore, as described above, pressure C2 interlocks the first shift valve 346 and the second shift valve 348. Therefore, even if the first shift solenoid valve 330 is de-energized and no longer supplies the main control pressure to the head of the first or second shift valve, the interlock formed by pressure C2 still maintains both shift valves in their traveling positions. Because the C2 latch holds shift valve 348 in the traveling position, the main pressure is blocked from being fed into C5.

[0189] If still Figure 17 As shown, when the first shift solenoid valve 330 is de-energized in the event of a power failure, the control main pressure can be slowly released, and an interlock is still applied at the head of the second shift valve 348 as it flows through the fluid path via the third shift valve 350. In practice, in this embodiment, a high-speed logic valve latch or interlock can be applied to the second shift valve 348 to maintain it in its traveling position. The slow release of the control main pressure may be partly due to the check valve 352 and the restriction in the fluid path. When operating in the seventh range, hydraulic fluid at the control main pressure can be fed directly from the control main valve 334 to the main modulation solenoid valve 340 and the third shift valve 350. This same flow path will be described below with respect to the actuation of the booster plug 328.

[0190] In either case, hydraulic fluid at the control of the main pressure can flow through the third shift valve (e.g., between the third valve section 2008 and the fourth valve section 2010) and through the first parallel check valve 352 (in Figure 17The first check valve 352 can include a check ball that permits flow in the direction from the third shift valve 350 to the second shift valve 348, but prevents backflow of hydraulic fluid from the second shift valve 348 to the third shift valve 350. As a result, when power is lost in the seventh range (or sixth, eighth, and ninth forward ranges) and the first and second shift solenoids are de-energized, the hydraulic pressure at the control main pressure at the head of the first shift valve 346 and the second shift valve 348 cannot return through the third shift valve 350 due to the first check valve 352.

[0191] As also shown in Figure 17 the second check valve 352 is located directly above the second shift valve 348. This second check valve 352 also includes a check ball that allows fluid to flow from left to right in the figure, but the ball sits in the valve to prevent flow from right to left. Although not shown in Figure 17 there is a flow restriction in the parallel flow path directly below the second check valve 352 such that it partially restricts the flow of hydraulic fluid from the second shift valve 348 to the first shift valve 346 (i.e., from right to left in Figure 13 This is shown in Figure 17 where the hydraulic fluid to the left of the restriction is shown as drain, and the hydraulic fluid to the right of the restriction is shown as control main pressure. As a result, due to the restriction and the second check valve 352, the hydraulic fluid at the control main pressure at the top or head of the second shift valve 348 slowly drains. Thus, the hydraulic pressure is high enough that a latch or interlock is formed to maintain the second shift valve 348 in its travel position. The C2 can vent in this case, but the first and second shift valves remain in their travel positions. Other means can be included in other embodiments to restrict the drain in the control system 300.

[0192] It should be further noted that if the C2 is allowed to vent, a high speed C3 neutral can be achieved without any actuation or movement of the first shift valve 346 or the second shift valve 348. Thus, while it has been described herein that it is feasible to default to the seventh range when operating in the higher ranges, the control system 300 is also capable of defaulting to a high speed neutral in the event of a power failure or loss of power. Additionally, the second pressure switch 358 can continue to be pressurized such that the controller is able to detect the position of the second shift valve 348 in the event of a failure or loss of power.

[0193] In addition to having a high speed neutral with only C3 forced, the control system can default to the seventh range with both C2 and C3 forced. For example, assume the operator is operably controlling the transmission in a higher forward range such as the sixth, seventh, eighth, or ninth range. If the operator shifts into neutral, but power is suddenly interrupted, the control system can be adapted to operably control to the aforementioned high speed C3 neutral, or alternatively, the control system can determine that the shift into neutral was accidental and maintain C2 forced such that the transmission defaults to the high speed power off range of the seventh range. If the operator does shift into neutral and the control system detects that this is the intended shift, then in the event of a power off, C2 can be vented and the transmission control system 300 can default to the C3 neutral. Furthermore, if power is not interrupted, the control system can still end in the C3 or C5 neutral.

[0194] Referring to Figure 14 illustrates the control system 300 operably controlling the transmission in the eighth forward range or eighth range. In the eighth range, C2 and C4 are forced and no other torque transmitting mechanisms are forced. In this range, the controller can energize the second pressure control solenoid 312 and the fourth pressure control solenoid 320. The first, third, and fifth pressure control solenoids are de-energized. Additionally, the controller can energize the first shift solenoid 330 and de-energize the second shift solenoid 332.

[0195] With the third shift valve 350 not stroked due to the second shift solenoid 332 being de-energized, the third shift valve 350 can block hydraulic fluid flow to the first trim system. Thus, Cl is blocked from receiving fluid and thus is not forced. Additionally, the third pressure control solenoid 316 is de-energized and thus the third trim valve 318 is in its un-stroked position. In this position, the main pressure from the pressure source 302 is blocked by the third trim valve 318 such that fluid cannot fill and force C3. C3 is thus not forced in the eighth range.

[0196] The first shift valve 346 is directly flow passable coupled to the pressure source 302 and in the event the first shift solenoid 330 is energized, the first shift valve 346 is in its stroked position. Hydraulic fluid is thus able to flow through the first shift valve 346 in several flow paths. The first flow passably couples the first shift valve 346 to the fifth trim system. This same fluid path is used to fill and force C6 when the fifth pressure control solenoid 324 is energized. However, in the eighth range, the fifth pressure control solenoid 324 is de-energized and the fifth trim valve 326 thus blocks the fluid path and prevents hydraulic fluid from filling and forcing C6. C6 is thus not forced in the eighth range.

[0197] The main pressure can flow through different fluid paths from the first shift valve 346 to the second shift valve 348. Here, with the first shift solenoid 330 energized, the second shift valve 348 is actuated to its stroked position, and thus the second shift valve 348 is flow-communicated to the pressure source 302. Hydraulic fluid can flow through the first and second shift valves to the second trim system. With the second pressure control solenoid 312 energized, the second trim valve 314 can be stroked, thereby allowing fluid to flow through the second trim valve 314. As it flows through the second trim valve 314, the fluid flows back to the second shift valve 348 and fills C2. C2 is thus force-filled in the eighth range.

[0198] In addition to filling and force-filling C2, hydraulic fluid is fed to the boost valve 354 and actuates the boost pressure against C2. In some embodiments, this can increase the C2 pressure to approximately the main pressure. If necessary, the second trim system can adjust or trim the C2 pressure. Furthermore, with the second shift valve 348 stroked, the main pressure is blocked from feeding C5. Thus, based on the position of the second shift valve 348, C5 is not forceable in the eighth range.

[0199] The main pressure from the fluid source 302 is directly fed or flow-communicated to the fourth trim system. In the eighth range, the controller energizes the fourth pressure control solenoid 320, which actuates the fourth trim valve 322 to its stroked position. In so doing, hydraulic fluid is able to fill and force-fill C4 in the eighth range. Thus, C2 and C4 are force-filled in the eighth range.

[0200] In the event of a power interruption while operating in the eighth range, the control system 300 can be designed to default to the seventh range in a similar manner as operating in the sixth or seventh range. Here, C4 is vented, and C3 is force-filled. As already described, when de-energized, the three high pressure control solenoids output full pressure, and the two low pressure control solenoids output zero pressure. Furthermore, the two shift solenoids are de-energized.

[0201] With the second shift solenoid 332 de-energized, the third shift valve 350 is set in its de-stroked position. In its de-stroked position, the third shift valve 350 blocks hydraulic fluid feed to CI. Additionally, with both de-energized normally low pressure control solenoids, the fourth trim valve 322 and the fifth trim valve 326 are de-stroked and thus block hydraulic fluid feed to C4 and C6. In other words, in the eighth range, the fourth pressure control solenoid 320 is energized by the controller such that C4 is forced, but when de-energized, the controller no longer sends current to the fourth pressure control solenoid 320. Once this occurs, the fourth pressure control solenoid 320 outputs zero pressure to the fourth trim valve 322, thereby causing the fourth trim valve 322 to move from its stroked position to its de-stroked position. In so doing, the fourth trim valve 322 blocks hydraulic fluid from filling C4 and the C4 pressure is thus able to bleed off.

[0202] In the eighth range, C3 is not forced, but when de-energized, the third pressure control solenoid 316 outputs full pressure to thereby move the third trim valve 318 to its stroked position. In so doing, primary pressure is fed to the third trim system such that C3 is forced. Also, C2 is forced in the eighth range and remains forced in the event of de-energization. The second pressure control solenoid is a normally high solenoid and thus, it outputs full pressure to keep the second trim valve 314 stroked. The C2 pressure further acts on the differential areas of the first shift valve 346 and the second shift valve 348 to hydraulically keep the shift valves in their stroked positions. In other words, an interlock is created on the two shift valves to keep them stroked. The shift valve 348 thus blocks primary feed to C5. With the first and second shift valves stroked and with the first shift valve 346 directly flowable coupled to the pressure source 302, hydraulic fluid can continue to flow through the shift valves and the second trim system before returning to the second shift valve 348 and feeding C2. Thus, as shown in Figure 14 C2 and C3 are forced in the high default range (i.e., the seventh range).

[0203] Referring to Figure 14 , the control system 300 is operable to control the transmission in a ninth forward range (i.e., the ninth range). In the ninth range, C2 and C6 can be forced. To do so, the controller can energize the second pressure control solenoid 312 and the fifth pressure control solenoid 324. The first shift solenoid 330 is energized, but the second shift solenoid 332 is de-energized, as shown in Figures 3-17As shown in the diagram, when the first shift solenoid valve 330 is energized, the main control pressure is fed into the heads of both the first shift valve 346 and the second shift valve 348 via the solenoid valve 330, thereby placing both valves in their travel positions. As will also be described below, pressure C2 can apply pressure to the differential regions on the two valves to form an interlock and hydraulically hold the first and second shift valves in their travel positions.

[0204] When the second and fifth pressure control solenoid valves are energized, the second fine-tuning valve 314 and the fifth fine-tuning valve 326 are in their advancing positions. Conversely, when the first, third, and fourth pressure control solenoid valves are de-energized, the first fine-tuning valve 310, the third fine-tuning valve 318, and the fourth fine-tuning valve 322 are in their non-advanced positions. Furthermore, when the second shift solenoid valve 332 is de-energized, in the ninth range, the third shift valve 350 is in its non-advanced position.

[0205] As previously described, in the seventh and eighth ranges, the second shift solenoid valve 332 is de-energized, and as in Figure 21 As shown, it is also de-energized in the ninth range. By de-energizing it, the third shift valve 350 is positioned in its non-operating position, thereby preventing hydraulic fluid from flowing and filling C1. In effect, when the transmission is operating in higher ranges (i.e., the seventh, eighth, and ninth ranges), C1 cannot be subjected to force, protecting the transmission from potential damage if C1 were to occur in any of these higher ranges. Therefore, the third shift valve 350 provides protective features for the control system 300 and the transmission.

[0206] Because the third pressure control solenoid valve 316 and the fourth pressure control solenoid valve 320 are de-energized, the third fine-tuning valve 318 and the fourth fine-tuning valve 322 do not advance, and thus prevent hydraulic fluid from filling C3 or C4. Therefore, in the ninth range, no force is applied to C3 and C4. Although this is the case, Figure 21 The diagram also shows that the main pressure is fed directly from the fluid source 302 to the third and fourth fine-tuning systems. For this purpose, Figure 14 Mechanized diagram 2100 illustrates that both C3 and C4 can be subjected to force in any range (i.e., reverse, neutral, or the first through ninth range). If the controller energizes only the third or fourth pressure control solenoid valve, hydraulic fluid will fill and exert force on C3 or C4. It is important to note that if de-energized, the normally low fourth pressure control solenoid valve 320 will be de-energized, and the output pressure will be zero. As described herein, when de-energized, the fourth fine-tuning valve 322 will not advance and will prevent fluid from filling C4.

[0207] anyway, Figure 14The mechanization chart 2100 in FIG. 12 provides the following overview: depending on which solenoids are energized by the controller, the torque transmission mechanism is available in each range. The chart also shows the corresponding hydraulic default range for each given steady state range in the event of de-energization. Another feature of the mechanization chart 2100 is the position of each shift valve. In this chart, a zero (0) indicates that the shift valve is not stroked, while a one (1) indicates that the shift valve is in its stroked position. In the ninth range, for example, the first and second shift valves are shown as stroked (1), and the third shift valve 350 is shown as not stroked (0). This is further illustrated by the arrows in the chart 2100, which show the direction of hydraulic fluid flow. The arrows in the chart 2100 are not intended to represent the magnitude of the fluid flow, but rather the direction of the flow. The direction of the flow is determined by the position of the shift valves and the energization of the solenoids. Figure 14 Embodiments of the present disclosure support.

[0208] Returning to FIG. 12, Figure 14 , the first shift valve 346 is in its stroked position. As such, hydraulic fluid can be supplied directly to the first shift valve 346 from the source 302. From the first shift valve 346, fluid can flow to the fifth trim system. As described above, the fifth trim valve 326 is stroked to allow fluid to fill and apply force to C6. Although not shown in the chart 2100, the valve gain of the fifth trim valve 326 can be controlled such that a control main pressure can be fed to the boost plug 328. The control main pressure can flow through a passage 344 defined in the boost plug 328 and apply force against the head end of the fifth trim valve 326. In so doing, the boost plug 328 does not move with the fifth trim valve 326 to the stroked position, thereby changing the gain across the trim system. This is in contrast to the first and third ranges when C6 is applied force. In those ranges, the control main pressure is not fed directly to the boost plug 328, and in those lower ranges, the boost plug 328 moves with the fifth trim valve 326 to the stroked position. Figure 17

[0209] Figure 17 ​The diagram generally illustrates the control master pressure flowing to the booster plug 328. This control master pressure first exits the control master valve 334 and the control master filter 336, as described above. Hydraulic fluid at the control master pressure flows from the filter 336 and is directly fed to each pressure control solenoid valve and each shift solenoid valve. In the ninth range, the first shift solenoid valve 330 is energized and outputs hydraulic fluid at the control master pressure to the first and second shift valves. The control master pressure is also fed to the main modulation solenoid valve 340. Additionally, hydraulic fluid at the control master pressure can also be fed through the third valve portion 2008 and the fourth valve portion 2010 of the third shift valve 350 (here, it flows through the check valve 352) and to the head of the second shift valve 348 (i.e., on the top side of the first valve portion 1904). The same fluid flowing to the main modulation solenoid valve 340 and the third shift valve 350 is also fed through the second shift valve 348 and pressurizes the second pressure switch 358. As it proceeds, the fluid under the control of the main pressure is further directed to the fifth fine-tuning system, where it is fed into the opening of the booster plug 328. Here, the fluid flows through the channel 344, separating the booster plug 328 from the fifth fine-tuning valve 326.

[0210] In addition to applying force to C6, force is applied to C2 in a manner similar to that in the seventh and eighth ranges. Hydraulic fluid at the main pressure is fed directly from source 302 to the first shift valve 346. Through the traveling first shift valve 346, fluid can flow to the second shift valve 348. Through the traveling open second shift valve 348, hydraulic fluid can flow to the second fine-tuning system and through the second fine-tuning valve 314 (which is in its traveling position controlled by the second pressure solenoid valve 312). As fluid flows through the second fine-tuning system, it feeds back to the second shift valve 348, where it fills and applies force to C2. The C2 pressure can act on the differential region of the first shift valve 346 and the second shift valve 348 to create a hydraulic interlock on the two valves. Therefore, if power is interrupted in the ninth range and the main control pressure is lost at the heads of both shift valves, the C2 pressure can hydraulically hold the first shift valve 346 and the second shift valve 348 in their traveling positions.

[0211] In the event of a power outage while operating in the ninth range, the control system 300 can be configured to default to the seventh range, as in... Figure 22 As shown in the diagram. Here, the controller cannot supply current to either of the solenoid valves, and therefore, both the first and second shift solenoid valves are de-energized. Once the fifth fine-tuning valve 326 moves to its non-moving position, the normally low pressure control solenoid valves (i.e., solenoid valves 320 and 324) default to zero pressure output, and therefore C6 is vented. When the fourth fine-tuning valve 322 is in its non-moving position, C4 remains vented.

[0212] The constant high pressure control solenoid valve outputs full pressure to move its corresponding trim valve to its travel position. In other words, the first trim valve 310, the second trim valve 314, and the third trim valve 318 are set in their travel positions. However, CI is not able to be force because hydraulic fluid is blocked upstream by the un-travelled third shift valve 350. The latched shift valve 348 also prevents fluid flow to the C5 clutch.

[0213] As shown in ​ , hydraulic fluid at the main pressure flows directly from the pressure source 302 to the third trim system. Through the third trim valve 318 in its travel and open position, fluid is able to fill and force C3. The third trim valve 318 is able to trim or reduce hydraulic fluid from the main pressure to the C3 pressure to meet the needs of the control system 300. Thus, as described above, when the system was previously operating in the ninth range, C2 and C3 are forced at power down. With C2 and C3 forced, the control system 300 thus defaults to the seventh range.

[0214] Yet another embodiment of the present disclosure is shown in ​ . Here, one embodiment of a shift availability table 2200 is illustrated for a multi-speed transmission having at least nine forward ranges, a neutral range, and at least one reverse range. The table illustrates how many torque transfer mechanisms are released or engaged between consecutive ranges. For example, in the first range, C5 and C6 can be engaged (as shown above in the table). If a shift to the second range is desired, the table 2200 illustrates that only one (1) torque transfer mechanism changes between the first and second ranges. As described above, CI and C5 are forced in the second range. Thus, C5 is a common torque transfer mechanism, and it remains forced during the shift. Meanwhile, C6 can be unforced, and CI is forced during the shift. Similarly, if the controller wants to skip a range and shift from the first range to the third range, and thus "skip" the second range, the controller can do so by engaging only one new torque transfer mechanism and disengaging one torque transfer mechanism. As described above, CI and C6 are forced in the third range. Thus, if a skip from the first range to the third range is made, the controller can do so by controlling the control system 300 to release C5 and force CI. Here, C6 is the common torque transfer mechanism between the first and third ranges. These shifts can be desirable because the controller does not have to transition the control system 300 through neutral before achieving the desired range.

[0215] In another example, the transmission can operate in a fourth range having stressed C1 and C4. If the controller wants to upshift to the first range and skip the second and third ranges, the shift availability table 2200 indicates that two (2) new torque transmitting mechanisms will need to be stressed. In addition, both C1 and C4 will need to be disengaged during the upshift. Again, in the first range, C5 and C6 are stressed. To complete the upshift from the fourth range to the first range, the controller will operatively control the control system 300 such that the exhaust C1 and C4 when C5 and C6 are stressed.

[0216] Additionally, and as described above, the design of the control system 300 allows for deactivation of the second shift valve 332 to control the third shift valve 350 to its un-advanced position, which effectively blocks the primary feed of fluid to the second trim system. As a result, C5 cannot be stressed in the third, fourth, or fifth ranges. However, the logic state of this scenario does not negatively impact the skip shift capability of the control system 300. In addition, in the seventh, eighth, and ninth ranges, the third shift valve 350 is controlled to its un-advanced position, which effectively blocks the primary feed of hydraulic fluid to the first trim system. Thus, C1 cannot be stressed in these higher ranges, and therefore provides improved protection against failure modes of the control system 300, and it is able to do so without impacting the skip shift capability of the system.

[0217] For the purposes of this disclosure, upshift can refer to a shift transition from a lower range to a higher range (e.g., first range to second range), and downshift can refer to a shift transition from a higher range to a lower range (e.g., second range to first range). Skip shift can include either an upshift or a downshift, but when it is implemented, the control system skips one or more intermediate ranges in which the shift transition is completed (e.g., fourth range to first range skipping the second and third ranges). In addition, the gear ratio from the input to the output of the transmission can be greater than 1.0 in a lower range, while the gear ratio can be less than 1.0 in a higher range. In one embodiment, one of the ranges can provide a gear ratio equal to or approximately 1.0. Regardless, the gear ratio can depend on the architecture of the transmission, and one of skill in the art will appreciate the different gear ratios based on different multi-speed transmission architectures. Thus, the present disclosure does not provide any specific gear ratio for any given range.

[0218] While exemplary embodiments incorporating the principles of the present disclosure have been disclosed above, the present disclosure is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses or adaptations of the present disclosure using its general principles. Further, this application is intended to cover variations of the present disclosure that are known or obvious to those of ordinary skill in the art once disclosed in the background of the present disclosure.

Claims

1. An electro-hydraulic control system for a multi-stage transmission, characterized in that, include: A controller for operablely controlling the transmission; A fluid source, used to supply hydraulic fluid; Multiple torque transmission mechanisms are operablely selectable between a stressed and unstressed state to achieve multiple ranges including at least one reverse gear range, a neutral gear range, and multiple forward gear ranges, wherein the multiple torque transmission mechanisms include at least a first torque transmission mechanism, a second torque transmission mechanism, and a third torque transmission mechanism. Multiple fine-tuning systems, each of the multiple fine-tuning systems including a fine-tuning valve and a pressure control solenoid valve, the multiple fine-tuning systems being electrically connected to the controller, the multiple fine-tuning systems including at least a first fine-tuning system, a second fine-tuning system, a third fine-tuning system, a fourth fine-tuning system and a fifth fine-tuning system; A plurality of shift valves, each of the plurality of shift valves being configured to be in fluid communication with the fluid source and to be movable between a traveling position and a non-traveling position, the plurality of shift valves including at least a first shift valve, a second shift valve and a third shift valve; A first shift solenoid valve and a second shift solenoid valve, each configured to be electrically connected to the controller, wherein the first shift solenoid valve is operablely controlled between energized and de-energized states to control the movement of the first shift valve and the second shift valve, and the second shift solenoid valve is operablely controlled between energized and de-energized states to control the movement of the third shift valve. Among them, in any one of the plurality of forward gear ranges, only two of the plurality of torque transmission mechanisms are in the force state; Among them, at least three of the plurality of pressure control solenoid valves are normally high solenoid valves, and the other pressure control solenoid valves are normally low solenoid valves. In addition, among them: When operating within the first forward gear range of the plurality of forward gear ranges and when electrical communication between the controller and each of the pressure control solenoid valve and the first and second shift solenoid valves is disabled, the normally high solenoid valve outputs full pressure, the normally low solenoid valve outputs no pressure, the first and second shift solenoid valves output no pressure, and the first and third torque transmission mechanisms are set to a stressed state to achieve the first power-off range, while the other torque transmission mechanisms are set to an unstressed state; and When operating in the second forward gear range of the plurality of forward gear ranges and when electrical communication between the controller and each of the pressure control solenoid valves and the first shift solenoid valve and the second shift solenoid valve is disabled, the normally high solenoid valve outputs full pressure, the normally low solenoid valve does not output pressure, the first shift solenoid valve and the second shift solenoid valve do not output pressure, and the first torque transmission mechanism and the second torque transmission mechanism are set to a stressed state to achieve the second power-off range, while the other torque transmission mechanisms are set to an unstressed state; In addition, among them: When the third shift valve is in its non-moving position, the third shift valve blocks the fluid communication between at least two of the fluid sources and the torque transmission mechanism.

2. The electro-hydraulic control system according to claim 1, characterized in that, When operating in the neutral range and when electrical communication between the controller and each of the pressure control solenoid valve and the first and second shift solenoid valves is disabled, the normally high solenoid valve outputs full pressure, the normally low solenoid valve does not output pressure, and the first and second shift solenoid valves do not output pressure, such that only one of the plurality of torque transmission mechanisms is in the stressed state to achieve the third de-energized range, and none of the other torque transmission mechanisms in the unstressed state are in a circulating connection to the fluid source.

3. The electro-hydraulic control system according to claim 1, characterized in that, When operating in the reverse gear range and when electrical communication between the controller and each of the pressure control solenoid valve, the first shift solenoid valve, and the second shift solenoid valve is disabled, the normally high solenoid valve outputs full pressure, the normally low solenoid valve does not output pressure, the first shift solenoid valve and the second shift solenoid valve do not output pressure, and the third torque transmission mechanism and another of the plurality of torque transmission mechanisms are set to a stressed state to achieve the third power-off range, while the other torque transmission mechanisms are set to an unstressed state.

4. The electro-hydraulic control system according to claim 1, characterized in that, The other torque transmission mechanism is neither the first torque transmission mechanism nor the second torque transmission mechanism.

5. The electro-hydraulic control system according to claim 1, characterized in that, The first forward gear range among the plurality of forward gear ranges includes a first range, a second range, a third range, a fourth range, and a fifth range; and The second forward gear range among the plurality of forward gear ranges includes the sixth range, the seventh range, the eighth range, and the ninth range.

6. The electro-hydraulic control system according to claim 1, characterized in that, The first power-off range includes the fifth range among the plurality of forward gear ranges, and the second power-off range includes the seventh range among the plurality of forward gear ranges.

7. The electro-hydraulic control system according to claim 1, characterized in that, If the second shift valve is in its traveling position, one of the plurality of torque transmission mechanisms is openly connected to the fluid source, and the other of the plurality of torque transmission mechanisms is openly disconnected from the fluid source; and If the second shift valve is in its non-moving position, another torque transmission mechanism of the plurality of torque transmission mechanisms is connected in flow to the fluid source, and one of the torque transmission mechanisms of the plurality of torque transmission mechanisms is disconnected from the fluid source.

8. The electro-hydraulic control system according to claim 7, characterized in that, Also includes: A first flow path is configured to allow hydraulic fluid to flow through the first flow path, and when the second shift valve is in its traveling position, the first flow path is defined between the fluid source and one of the plurality of torque transmission mechanisms. and A second flow path is configured to allow hydraulic fluid to flow through the second flow path, which is defined between the fluid source and another of the plurality of torque transmission mechanisms when the second shift valve is in its non-moving position. The second fine-tuning system is in fluid communication with the first flow path and the second flow path to control the hydraulic flow to one and the other of the plurality of torque transmission mechanisms.

9. The electro-hydraulic control system according to claim 1, characterized in that, In the travel position of the third shift valve, the flow path is defined for hydraulic fluid to flow through the third shift valve via the second fine-tuning system between the fluid source and at least one of the plurality of torque transmission mechanisms; and In the non-traveled position of the third shift valve, the flow path is blocked by the third shift valve to prevent hydraulic fluid from flowing from the fluid source to at least one of the plurality of torque transmission mechanisms.

10. The electro-hydraulic control system according to claim 9, characterized in that, In at least three of the plurality of forward gear ranges, the third shift valve is positioned in the non-moving position to block the flow path.

11. An electro-hydraulic control system for a multi-stage transmission, characterized in that, include: A controller for operablely controlling the transmission; A fluid source, used to supply hydraulic fluid; Multiple torque transmission mechanisms are operablely selectable between a stressed and unstressed state to achieve multiple ranges including at least one reverse range, a neutral range, and multiple forward ranges; A first fine-tuning system includes a first pressure control solenoid valve and a first fine-tuning valve, wherein the first pressure control solenoid valve is electrically connected to the controller. The second fine-tuning system includes a second pressure control solenoid valve and a second fine-tuning valve, wherein the second pressure control solenoid valve is electrically connected to the controller. The third fine-tuning system includes a third pressure control solenoid valve and a third fine-tuning valve, wherein the third pressure control solenoid valve is electrically connected to the controller. The fourth fine-tuning system includes a fourth pressure control solenoid valve and a fourth fine-tuning valve, wherein the fourth pressure control solenoid valve is electrically connected to the controller; The fifth fine-tuning system includes a fifth pressure control solenoid valve and a fifth fine-tuning valve, wherein the fifth pressure control solenoid valve is electrically connected to the controller; A plurality of shift valves, each configured to be in fluid communication with the fluid source and to move between a traveling position and a non-traveling position, the plurality of shift valves including at least a first shift valve, a second shift valve and a third shift valve; as well as A pressure switch is fluidly connected to the third shift valve and electrically connected to the controller, wherein the pressure switch electrically connects the position of the third shift valve to the controller; In any one of the plurality of ranges, only two of the plurality of torque transmission mechanisms are in the stress state.

12. The electro-hydraulic control system according to claim 11, characterized in that, When the third shift valve is in the non-moving position, the third shift valve blocks the fluid communication between the fluid source and at least two of the plurality of torque transmission mechanisms.

13. The electro-hydraulic control system according to claim 11, characterized in that, Of the first pressure control solenoid valve, the second pressure control solenoid valve, the third pressure control solenoid valve, the fourth pressure control solenoid valve, and the fifth pressure control solenoid valve, three are normally high-pressure solenoid valves, while the other two are normally low-pressure solenoid valves.

14. The electro-hydraulic control system according to claim 11, characterized in that, In the travel position of the third shift valve, the flow path is defined for hydraulic fluid to flow through the third shift valve via the first fine-tuning system between the fluid source and at least one of the plurality of torque transmission mechanisms; and In the non-traveled position of the third shift valve, the flow path is blocked by the third shift valve to prevent hydraulic fluid from flowing from the fluid source to at least one of the plurality of torque transmission mechanisms.

15. The electro-hydraulic control system according to claim 14, characterized in that, In at least three of the plurality of forward gear ranges, the third shift valve is positioned in the non-moving position to block the flow path.

16. An electro-hydraulic control system with multiple torque transmission mechanisms for a multi-stage transmission, characterized in that, include: A controller for operablely controlling the transmission; A fluid source, used to supply hydraulic fluid; The plurality of torque transmission mechanisms are operablely selectable between a stressed and unstressed state to achieve a plurality of ranges including at least one reverse range, a neutral range, and a plurality of forward ranges. Multiple fine-tuning systems, which are electrically connected to the controller and fluidly connected to the fluid source, wherein each of the multiple fine-tuning systems includes a pressure control solenoid valve and a fine-tuning valve; A first shift valve is configured to be in direct fluid communication with the fluid source, and the first shift valve is movable between a moving position and a non-moving position. The second shift valve is configured to be in direct fluid communication with two of the plurality of torque transmission mechanisms, and the second shift valve is movable between a traveling position and a non-traveling position; The third shift valve is configured to be in direct fluid communication with the fluid source, and the third shift valve is movable between the moving position and the non-moving position. A first shift solenoid valve is configured to be electrically connected to the controller, and the first shift solenoid valve is operablely controllable between energized and de-energized states to control the movement of the first shift valve and the second shift valve; and The second shift solenoid valve is configured to be electrically connected to the controller, and the second shift solenoid valve is operablely controlled between energized and de-energized states to control the movement of the third shift valve. In any of the plurality of ranges, only two of the plurality of torque transmission mechanisms are in the force state; Furthermore, the controller is electrically connected to each of the pressure control solenoid valve, the first shift solenoid valve, and the second shift solenoid valve to operably shift gears between a first forward gear range and a second forward gear range, wherein at least one of the plurality of forward gear ranges is skipped during the shift from the first forward gear range to the second forward gear range.

17. The electro-hydraulic control system according to claim 16, characterized in that, At least three of the plurality of pressure control solenoid valves are normally high solenoid valves, and the other pressure control solenoid valves are normally low solenoid valves.

18. The electro-hydraulic control system according to claim 16, characterized in that, Also includes: At least one on / off shift solenoid valve is configured to be electrically connected to the controller, and the at least one on / off shift solenoid valve is configured to be fluidly connected to the third shift valve to control the movement of the third shift valve between the moving position and the non-moving position.

19. The electro-hydraulic control system according to claim 16, characterized in that, If the second shift valve is in the traveling position, the first torque transmission mechanism of the plurality of torque transmission mechanisms is fluidly connected to the fluid source, and if the third shift valve is in the non-traveling position, the second torque transmission mechanism of the plurality of torque transmission mechanisms is fluidly connected to the fluid source.

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