Patent application number | Description | Published |
20080305911 | Eight Speed Automatic Transmission with Dual Area Clutch Piston - A transmission includes four planetary gearsets and five torque transmitting devices operative to provide eight forward speed ratios. At least one of the torque transmitting devices is engaged during two different speed ratios. The torque transmitting device includes a piston partially defining two separate and independently pressurizable chambers. Accordingly, the transmission enables both chambers to be pressurized for speed ratios in which a high torque capacity is required of the torque transmitting device, and only one of the chambers to be pressurized for speed ratios in which a low torque capacity is required of the torque transmitting device. | 12-11-2008 |
20090211850 | LUBRICATION CONTROL SYSTEM FOR AUTOMATIC TRANSMISSIONS - An automatic transmission lubrication control system includes a modulating, spring biased spool valve and feedback circuit. One end of the spool valve is supplied with line pressure hydraulic fluid. The valve spool modulates a flow of lubricating hydraulic fluid from the cooler and its position is determined by a force balance between the line pressure, the regulated fluid output pressure to the lubrication system and the force of the biasing spring. In a reduced lubrication state, a signal from a transmission control module opens a solenoid valve to provide high pressure fluid to a three way check valve which closes the feedback circuit and applies high pressure fluid to the opposite end of the valve spool. This action moves the valve spool to a travel limit, closing off flow from the cooler. Hydraulic fluid from the torque converter feed is then routed to the lubrication system. | 08-27-2009 |
20090211862 | CLUTCH WITH DUAL AREA PISTON AND INDEPENDENT PRESSURE CONTROL - The present invention provides a clutch having two pistons, a first piston defining a first, smaller area and a second piston, defining a second, larger area. The separate pistons are independently provided with flows of pressurized hydraulic fluid from first and second independent modulatable control valves. Engagement of the clutch may be rapid by providing hydraulic fluid to the smaller area piston, provide greater engagement force by providing hydraulic fluid to the larger area piston or a combination of speed and force by utilizing modulated or unmodulated flows of hydraulic fluid to both pistons. | 08-27-2009 |
20090247343 | AUTOMATIC TRANSMISSION GEAR AND CLUTCH ARRANGEMENT - A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque-transmitting devices. Further, a hydraulic fluid control circuit is provided for controlling the operation of the plurality of torque-transmitting devices. The hydraulic fluid control circuit receives pressurized hydraulic fluid from an off-axis hydraulic fluid pump and has a plurality of fluid passages disposed in the transmission house, input shaft, output shaft and other coupling members. | 10-01-2009 |
20090288927 | MULTI-AREA CLUTCH ASSEMBLY - A torque transmitting assembly includes an actuator for engaging a torque transmitting element. A mechanism is connected to the actuator. The mechanism is operable to selectively allow fluid communication therethrough. The mechanism communicates between two separate fluid spaces located on opposite sides of the actuator. During movement of the actuator, a fluid is allowed to transfer through the mechanism between the two separate fluid spaces. | 11-26-2009 |
20100040464 | SELF-PRIMING VANE PUMP - A self-priming vane pump includes a cylindrical rotor disposed in a cavity in a housing including inlet and outlet ports. The rotor defines a plurality of axially extending slots which each receive one of a like plurality of vanes. A garter spring or similar resilient annulus is disposed within the rotor and provides a radially outwardly directed force on the vanes which maintains their contact with the cavity walls during pump start-up and rapidly self-primes the pump. The spring or annulus rests against a shoulder within the hollow rotor and is retained therein by a pressed in collar. | 02-18-2010 |
20110077124 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING AN ACCUMULATOR - A hydraulic control system for actuating at least one torque transmitting device in a transmission includes a sump, a pump in communication with the sump, and an accumulator. A first control device and a second control device control the communication of hydraulic fluid between the pump, the accumulator, and the torque transmitting device. | 03-31-2011 |
20110118081 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING A MAIN LINE FEED ACCUMULATOR - A hydraulic control system for controlling a transmission includes an accumulator, a plurality of control devices, and a plurality of valves. The accumulator provides pressurized hydraulic fluid to a pressure control subsystem during an engine restart. The plurality of control devices includes solenoids and one way ball check valves. The plurality of valves include compensator feed valves, relay valves, and mode valves. | 05-19-2011 |
20110132711 | CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-09-2011 |
20110132716 | CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-09-2011 |
20110138956 | ELECTRO-HYDRAULIC CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a source of pressurized hydraulic fluid, first and second actuator control devices in downstream fluid communication with the source of pressurized hydraulic fluid, and first and second clutch control devices in downstream fluid communication with the source of pressurized hydraulic fluid. A valve is in downstream fluid communication with the first and second actuator control devices. Selective activation of combinations of the control devices allows for a pressurized fluid to engage the dual clutch and an actuator in order to shift the transmission into a desired gear ratio. | 06-16-2011 |
20110139564 | CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-16-2011 |
20110167812 | HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION HAVING ELECTRONIC TRANSMISSION RANGE SELECTION WITH FAILURE MODE CONTROL - A hydraulic control system for a transmission includes a source of pressurized hydraulic fluid that communicates with an electronic transmission range selection (ETRS) subsystem. The ETRS subsystem includes an ETRS valve, a park mechanism, first and second mode valve assemblies, a latch valve assembly, and a plurality of solenoids. The ETRS subsystem is configured to provide desired operating conditions during a plurality of potential failure conditions. | 07-14-2011 |
20110168509 | HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION HAVING A THREE PATH TORQUE CONVERTER CONTROL SUBSYSTEM - A hydraulic control system for a transmission includes a first source of pressurized hydraulic fluid for providing a first flow of hydraulic fluid, a second source of pressurized hydraulic fluid for providing a second flow of hydraulic fluid, and a torque converter control subsystem for controlling a torque converter and a torque converter clutch. The torque converter control subsystem includes a torque converter control valve and a solenoid. The solenoid is multiplexed to the torque converter control valve and the torque converter clutch. The torque converter control valve is operable to control a flow of hydraulic fluid to the torque converter and to other subsystems within the hydraulic control system. | 07-14-2011 |
20110180364 | ELECTRO-HYDRAULIC CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 07-28-2011 |
20110197982 | HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION HAVING A LUBRICATION REGULATION VALVE - A hydraulic control system for a transmission includes a first source of pressurized hydraulic fluid, a second source of pressurized hydraulic fluid, a lubrication subsystem for communicating a pressurized hydraulic fluid through the transmission, and a fluid control device in communication with the first source of pressurized hydraulic fluid. A lubrication regulation valve is in communication with the first and second sources of pressurized hydraulic fluid, the fluid control device, and the lubrication subsystem. The lubrication regulation valve allows fluid communication from the first source of pressurized hydraulic fluid to the lubrication subsystem when in a first position, the valve allows fluid communication from the first and second source of pressurized hydraulic fluid to the lubrication subsystem when in a second position, and the valve allows fluid communication from the first source of pressurized hydraulic fluid through the flow restriction device to the lubrication subsystem when in a third position. | 08-18-2011 |
20110257855 | CONTROL SYSTEM AND METHOD FOR SHIFT FORK POSITION IN DUAL CLUTCH TRANSMISSIONS - A control system includes a pressure control solenoid and a flow control solenoid having an input in fluid communication with the pressure control solenoid. A piston adjusts a position of a shift fork and includes a first area in fluid communication with the pressure control solenoid and a second area in fluid communication with the flow control solenoid. A fork sensor senses a position of a shift fork. A flow determining module determines a fork velocity for the shift fork, adjusts the fork velocity to generate an adjusted fork velocity based on the position, and generates a flow command for the flow control solenoid based on the adjusted fork velocity. A pressure determining module generates a pressure command for the pressure control solenoid. The shift fork is at least one of moved from a sync position to an engaged position and from an engaged position to a neutral position. | 10-20-2011 |
20110257857 | CONTROL SYSTEM AND METHOD FOR SYNCHRONIZATION CONTROL IN DUAL CLUTCH TRANSMISSIONS - A control system includes a pressure control solenoid and a flow control solenoid having an input in fluid communication with the pressure control solenoid. A piston adjusts a position of a shift fork and includes a first area in fluid communication with the pressure control solenoid and a second area in fluid communication with the flow control solenoid. A fork sensor senses a position of a shift fork. A slip sensing module estimates slip acceleration between an input shaft and a gear. A flow determining module generates a flow command for the flow control solenoid. A sync control module determines a slip acceleration profile including an estimated slip acceleration, adjusts the estimated slip acceleration based on the measured slip acceleration, and generates a pressure command for the pressure control solenoid based on the adjusted slip acceleration. | 10-20-2011 |
20120137806 | METHOD OF CONTROLLING A DUAL CLUTCH TRANSMISSION - A method of controlling a hydraulic control system for a dual clutch transmission includes controlling a plurality of pressure and flow control devices in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-07-2012 |
20120138406 | ELECTRO-HYDRAULIC CONTROL SYSTEM FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-07-2012 |
20120138408 | METHOD OF CONTROLLING A DUAL CLUTCH TRANSMISSION - A method of controlling a hydraulic control system for a dual clutch transmission includes controlling a plurality of pressure and flow control devices in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-07-2012 |
20120138413 | APPARATUS FOR AND METHOD OF CONTROLLING A DUAL CLUTCH TRANSMISSION - The present invention provides a method of operating an electro-hydraulic control system for a dual clutch transmission having seven forward speeds or gear ratios and reverse. The control system includes an oil delivery subsystem, a clutch control subsystem and a synchronizer control subsystem. All three subsystems are under the control of a transmission control module. The method of operation includes gathering data from various shaft speed, clutch position and shift actuator position sensors and utilizing pressure control (PCS) and flow control (FCS) solenoid valves and a logic valve to pre-stage and engage (and disengage) hydraulic shift actuators associated with a requested and current gear and to sequentially engage one of a pair of input clutches. | 06-07-2012 |
20120145502 | ELECTRO-HYDRAULIC CONTROL SYSTEM AND METHOD FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system for a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-14-2012 |
20120145503 | ELECTRO-HYDRAULIC CONTROL SYSTEM AND METHOD FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system and method for controlling a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-14-2012 |
20120145504 | CONTROL SYSTEM AND METHOD FOR A DUAL CLUTCH TRANSMISSION - A hydraulic control system and method for controlling a dual clutch transmission includes a plurality of pressure and flow control devices and logic valve assemblies in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the pressure control solenoids and the flow control solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio. | 06-14-2012 |
20120174570 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING FLOW AUGMENTATION - A system for providing pressurized hydraulic fluid includes an engine driven main pump and an electrical motor driven auxiliary pump. The auxiliary pump provides hydraulic fluid at line pressure to shift control subsystems during a vehicle launch while the main pump provides hydraulic fluid to cooler or lubrication subsystems during the vehicle launch. A pressure regulation valve regulates the pressure of the hydraulic fluid from the main pump. Once the main pump reaches a critical speed, the main pump provides hydraulic fluid at line pressure to the hydraulic control system and the auxiliary pump is turned off. | 07-12-2012 |
20120175210 | HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION HAVING A MANUAL VALVE WITH A TWO GEAR DEFAULT STRATEGY - A hydraulic control system for a transmission includes a source of pressurized hydraulic fluid, a manual valve, and a default valve. A first set of solenoids are configured to selectively engage at least one of a plurality of shift actuators. The first set of solenoids is open when de-energized. A second set of solenoids is configured to selectively engage at least one of the plurality of actuators. The second set of solenoids is closed when de-energized. A low speed default gear is engaged when the first and second sets of solenoids are de-energized and the transmission is operating in a low speed gear ratio. A high speed default gear ratio is engaged when the first and second sets of solenoids are de-energized and the transmission is operating in a high speed gear ratio. | 07-12-2012 |
20120247902 | ELECTRO-HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION - An electro-hydraulic control system for a multiple speed automatic motor vehicle transmission includes main and auxiliary hydraulic pumps, a line pressure regulator, a lubrication pressure regulator, a lubrication override control valve and a torque converter control valve which is controlled by a variable force solenoid (VFS). Driver commands are provided to the system through a manual logic or spool valve which functions in conjunction with a spool or logic default valve and a default solenoid. Five solenoid valves receive various flows of hydraulic fluid and supply them to hydraulic actuators that engage and disengage four friction clutches and a selectable one-way clutch. | 10-04-2012 |
20130112524 | HYDRAULIC CONTROL SYSTEM FOR AN AUTOMATIC TRANSMISSION - A hydraulic control system for a transmission includes a pressure regular subsystem, a transmission range selection control subsystem, and a clutch control subsystem. The pressure regulator subsystem includes a source of pressurized hydraulic fluid for providing a flow of hydraulic fluid. The transmission range selection control subsystem includes a set of four valve assemblies actuated by a pair of solenoids. And the clutch control subsystem provides pressurized hydraulic fluid to a plurality of clutch actuators activated by a plurality of variable force solenoids through a plurality of valve assemblies. The plurality of valve assemblies of the clutch control subsystem are in fluid communication with the transmission range selection control subsystem, and the transmission range selection control subsystem employs the pressurized hydraulic fluid to engage a range selection through the clutch control subsystem. | 05-09-2013 |
20130139495 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING AN ACCUMULATOR - A hydraulic control system for actuating at least one torque transmitting device in a transmission includes a sump, a pump in communication with the sump, and an accumulator. A first control device and a second control device control the communication of hydraulic fluid between the pump, the accumulator, and the torque transmitting device. | 06-06-2013 |
20130139496 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING AN ACCUMULATOR - A hydraulic control system for actuating at least one torque transmitting device in a transmission includes a sump, a pump in communication with the sump, and an accumulator. A first control device and a second control device control the communication of hydraulic fluid between the pump, the accumulator, and the torque transmitting device. | 06-06-2013 |
20130139497 | TRANSMISSION HYDRAULIC CONTROL SYSTEM HAVING AN ACCUMULATOR - A hydraulic control system for actuating at least one torque transmitting device in a transmission includes a sump, a pump in communication with the sump, and an accumulator. A first control device and a second control device control the communication of hydraulic fluid between the pump, the accumulator, and the torque transmitting device. | 06-06-2013 |
20130158824 | LIMITING BRANCH PRESSURE TO A SOLENOID VALVE IN A FLUID CIRCUIT - A vehicle includes a clutch, pump, pressure control variable force solenoid (PVFS) valve in a branch supplying oil from the pump to the clutch through a flow control VFS (QVFS), and a controller. The controller calculates an area of a variable orifice of the QVFS valve at the start of a clutch shift, records the area as a maximum area, and calculates a maximum branch pressure as a function of the area. The controller limits pressure in the branch during the shift event to the calculated maximum branch pressure. The transmission may be a dual-clutch transmission (DCT) with the clutch being a DCT input clutch. A control system includes a host machine, temperature and pressure sensors, a computer-readable medium with instructions for limiting branch pressure as a function of the maximum area noted above and using sensor values from the sensors. A method of limiting branch pressure is also disclosed. | 06-20-2013 |
20130184951 | CLOSED-LOOP CLUTCH CONTROL USING A FILTERED PISTON POSITION SIGNAL - A vehicle includes an engine, transmission, and controller. The transmission includes a clutch pack, a clutch piston, and a position sensor. The sensor measures a changing magnetic field with respect to the piston, and encodes the measured magnetic field as a raw position signal. The controller receives the raw position signal and processes the raw position signal through a signal processing module to generate a filtered signal attenuating signal noise in the position signal. The controller determines a commanded position of the piston, and calculates separate proportional (P), derivative (D), and integral (I) control terms using the commanded position and filtered position signal. The controller also calculates a feed-forward control term using the commanded position, and a required flow rate for actuating the clutch pack as a function of the PID terms and the feed-forward commanded position term. The controller actuates the clutch pack using the commanded flow rate. | 07-18-2013 |
20130240315 | DUAL-CLUTCH TRANSMISSION THERMAL MANAGEMENT - A method of cooling a multi-speed dual-clutch transmission (DCT) that is paired with an internal combustion engine in a vehicle includes detecting operation of the vehicle. The method also includes sensing an increase in temperature of a subsystem of the DCT while the vehicle is operating. The method also includes selecting a remedial action in response to the sensed temperature. The method aditionally includes activating the selected remedial action such that the temperature of the subsystem is reduced. | 09-19-2013 |
20130282243 | DUAL-CLUTCH TRANSMISSION THERMAL MANAGEMENT - A method of controlling thermal loading in a multi-speed dual-clutch transmission (DCT) that is paired with an internal combustion engine in a vehicle is provided. The method includes detecting operation of the vehicle and ascertaining a degree of thermal loading on the DCT. The method also includes selecting a remedial action corresponding to the ascertained degree of thermal loading. Additionally, the method includes activating the selected remedial action such that the thermal loading on the DCT is reduced. A vehicle having a DCT, an internal combustion engine, and a controller configured to control thermal loading in the DCT is also disclosed. | 10-24-2013 |
20130332038 | REAL TIME COMPENSATION OF CHANGING FRICTION CHARACTERISTICS OF A CLUTCH IN A TRANSMISSION - A method of controlling a transmission includes estimating an expected coefficient of friction of the clutch, estimating a value of an expected torque required to maintain a constant slip of the clutch for a current input torque applied to the transmission, and determining a value of an actual torque applied to the clutch to maintain the constant slip of the clutch at the current input torque. An actual coefficient of friction of the clutch is calculated by dividing the actual torque applied to the clutch by the expected torque applied to the clutch, and multiplying that quotient by the expected coefficient of friction of the clutch. A feed forward torque command is then adjusted based upon the actual coefficient of friction of the clutch to define a revised value of the feed forward torque command, which may then be used to control the clutch for various control operations. | 12-12-2013 |
20140195131 | UPSHIFT CONTROL OF A DRY DUAL-CLUTCH TRANSMISSION - A vehicle includes an engine, a dry dual-clutch transmission (dDCT) having a pair of input clutches and a gearbox containing oddly- and evenly-numbered gear sets, and a transmission control module (TCM). Application of one of input clutches connects the engine to a corresponding one of the oddly- or evenly-numbered gear sets. The TCM includes feed-forward PID-based control logic, and a torque-to-position (TTP) table for each input clutch. The TCM commands a position of a designated input clutch during a power-on upshift using the feed-forward, PID-based control logic, and selectively adapts the TTP table as a function of an inertia and acceleration value of the engine. The TCM may apply an asymmetrical handoff profile to commanded oncoming and offgoing clutch torques during the torque phase of the upshift. The TCM may also adjust the TTP table as a function of the frequency of use of the input clutches. | 07-10-2014 |
20140371998 | ADAPTIVE CONTROL OF A FLOW CONTROL SOLENOID - A vehicle includes an engine, a transmission, and a controller which executes a method. The transmission includes a clutch having an actuator which applies the clutch using position-based control logic. The transmission also includes a fluid pump and a variable-force or other solenoid valve positioned downstream of the pump and upstream of the clutch. The valve outputs a flow rate (Q) for a corresponding solenoid control current (I). The controller adapts a calibrated Q vs. I characteristic table of the valve for different transmission temperatures by applying closed-loop position control signals to the actuator at the different transmission temperatures and recording a null point(s) describing the corresponding solenoid control current (I) at a zero flow rate condition. The controller calculates an offset value for solenoid control current (I) using the recorded null point(s), applies the offset value to the characteristic table, and controls the clutch using the adapted characteristic table. | 12-18-2014 |