Gm Global Technolgoy Operations, Inc.

John E Marano

Zhen J Zhang

Joseph Brian Burtch

Jesse B Bradley

Andrew W Phillips

Vijay A Neelakantan

Xuefeng Tim Tao

Randall B Dlugoss

Christopher Jay Weingartz

Scott R Verna

Steven Patrick Moorman

Richard B Jess

Julian R Verdejo

Ronald F Lochocki, Jr

Todd R Berger

Robert L Moses

Jeffrey A Sell

Christopher G Benson

David W Wright

Zhe Xie

Nathaniel E Wilke

David Chris Webert

Christopher J Trush

James L Lanzon

Ed E Han

Jing Zhou

Sahm E Litkouhi

Artin Farahani

David Juhassz

Cole Reinhold

James M Gessner

Bradley J Lemmen

Craig M Fazakerly

A method and system for controlling a ratio of a continuously variable transmission coupling a prime mover to a driven member in a vehicle. The method includes determining a current ratio of the continuously variable transmission, determining a projected ratio from a first ratio path of a predetermined ratio map, calculating a gradient between the current ratio and the projected ratio, determining whether the calculated gradient satisfies a gradient constraint, setting a control ratio to the projected ratio if the calculated gradient satisfies the gradient constraint, setting a control ratio to a modified ratio if the calculated gradient does not satisfy the gradient constraint, the modified ratio being based upon a ratio that satisfies the gradient constraint, and controlling the ratio of the continuously variable transmission to the control ratio.

System and method for ratio control in a vehicle continuously variable transmission

A target ratio module selectively determines a target ratio of transmission input shaft speed to transmission output shaft speed independently of an accelerator pedal position and as a function of a vehicle speed and a driver axle torque request. A first pulley valve control module controls opening of a first valve based on the target ratio. The first valve controls transmission fluid flow to a first pulley actuator. The first pulley actuator is coupled to the transmission input shaft of a continuously variable transmission (CVT) and expands and contracts based on transmission fluid pressure. A second pulley valve control module controls opening of a second valve based on the target ratio. The second valve controls transmission fluid flow to a second pulley actuator. The second pulley actuator is coupled to the transmission output shaft of the CVT and expands and contracts based on transmission fluid pressure.

Transmission ratio control systems and methods

A method of controlling a variator that requires clamping pressure between a first component and a second component to transfer torque therebetween, such as a continuously variable transmission, includes calculating a theoretical clamping pressure, and multiplying the theoretical clamping pressure by a multiplier to define a commanded clamping pressure. The multiplier includes a value that is variable between a minimum multiplier value and a maximum multiplier value. The value of the multiplier is based on current operating conditions of the variator. The commanded clamping pressure is applied to the first component and the second component to generate friction and transfer torque between the first component and the second component.

Method of controlling a variator

A variable flow orifice for a hydraulic control system in a transmission includes a shape memory alloy that selectively increases and decreases the size of an orifice. The deformation of the shape memory alloy, and therefore the size of the orifice, is a function of the temperature of the transmission. During cold conditions the orifice size is increased and during normal operating conditions the size of the orifice is decreased.

Temperature dependent variable flow orifice

A vehicle includes an internal combustion engine, brake actuators configured to slow the vehicle in response to braking commands, and a transmission. The transmission includes a plurality of gear sets each having a plurality of nodes, an input member that is continuously connected to the engine and to a node of one of the gear sets, a reverse clutch, a binary clutch assembly, and a controller. The binary clutch assembly is connected at least to the same gear set as the input member, and is applied with the reverse clutch when entering a reverse gear state. The controller executes a method to transmit the braking commands to the brake actuators in response to a requested garage shift into a reverse gear state when the vehicle is rolling above a calibrated speed threshold, and thereby slows the vehicle until a calibrated target slip is achieved across the binary clutch assembly.

Garage shift control of a binary clutch assembly

A transmission for a motor vehicle with an engine includes a transmission housing and a dual clutch assembly with a clutch housing connectable to an engine output member. The clutch housing is rotationally supported within the transmission housing. The selective engagement of the dual clutch assembly interconnects the dual clutch housing with at least one of a first input member and a second input member. The transmission also includes a plurality of gear sets associated with various forward and reverse gear ratios, a controller implemented with an algorithm that provides a lock-up profile for the dual clutch assembly, and a plurality of synchronizer assemblies that couple at least one of the gear sets with at least one of a first countershaft and a second countershaft. The selective engagement of at least one of the synchronizer assemblies establishes at least one of the forward speed ratios.

Dual clutch transmission

A vehicle includes an engine, drive wheels, a continuously variable transmission (CVT), and a controller. The CVT includes an input member connected to the engine, an output member delivering output torque to the wheels, and a variator assembly connecting the input and output members. The controller determines, via a method, an input and output speed of the variator assembly, converts the output speed to an equivalent input speed using a calibrated variator speed ratio, and calculates a gross slip of the variator assembly using the input and equivalent input speeds. A gross slip flag is set only when the gross slip exceeds a calibrated slip value for a predetermined duration. A CVT assembly includes the controller, input and output members, and variator assembly. The variator assembly may include drive and driven pulleys, a drive mechanism connecting the pulleys, and an actuator applying a clamping force to one of the pulleys.

Gross slip-based control of a variator assembly

A method of managing clutch thermal loads in a multi-speed dual-clutch transmission (DCT) that is paired with an internal combustion engine in a vehicle is provided. The method includes assessing operation of the DCT and ascertaining a mode of operation of a clutch in the DCT. The method also includes predicting, in response to the ascertained mode of operation of the clutch, an amount of time remaining until the clutch reaches a threshold temperature. The method additionally includes ascertaining whether the predicted amount of time remaining until the clutch reaches the threshold temperature is within a predetermined range of time. Furthermore, the method includes activating an indicator configured to signal that the predicted amount of time remaining is within the predetermined range of time. A vehicle having a DCT, an internal combustion engine, and a controller configured to predict thermal loading on a clutch in the DCT is also disclosed.

Dual-clutch transmission predictive thermal protection

A vehicle includes an engine and transmission having gear sets, an input member that is continuously connected to the engine and a gear set, a binary clutch assembly, a speed sensor, and a controller. The binary clutch assembly includes a freewheeling element holding torque in one rotational direction, and also a selectable one-way clutch (SOWC) portion holding torque in two rotational directions when applied. The controller executes a method to transmit a first binary clutch command to the binary clutch assembly and thus apply the SOWC portion at vehicle launch, and calculates, via the processor, an acceleration value of the vehicle using the measured speed. The controller also selects a shift apply point of the binary clutch assembly as a function of the calculated acceleration value, and transmits a second binary clutch command to the binary clutch assembly to release the SOWC portion at the selected shift apply point.

Acceleration-based state control of a binary clutch assembly

A hydraulic control system for a transmission of a motor vehicle includes a source of pressurized hydraulic fluid that communicates with an analog electronic transmission range selection (ETRS) subsystem or a manual valve. The ETRS subsystem includes an ETRS valve, a park servo, a park mechanism, a mode valve, and a plurality of solenoids. The ETRS and manual valve communicate with a clutch actuator subsystem that engages a one-way clutch and six clutches/brakes.

Hydraulic control system for an automatic transmission

A control system for an automatic transmission includes a double transition shift detection module and first and second clutch control modules. The double transition shift detection module detects whether a double transition shift operation is requested. The first clutch control module controls two of four transitioning clutches of the transmission during an inertia phase of the double transition shift operation. The second clutch control module controls each of the four transitioning clutches of the transmission during a torque phase of the double transition shift operation.

System and method for improved double transition shift operations for automatic transmissions

A control system for a dry dual clutch transmission (DCT) includes first, second, and third modules. The first module detects whether a hydraulic pressure sensor of a hydraulic fluid delivery system in the dry DCT has failed. The second module estimates a pressure of hydraulic fluid within an accumulator of the hydraulic fluid delivery system based on one of (i) torque generated by and temperature of a hydraulic fluid pump and (ii) a drain down period of the accumulator and a period since the hydraulic fluid pump was on. The third module controls start/stop of the hydraulic fluid pump based on the estimated hydraulic fluid pressure when the hydraulic pressure sensor has failed.

System and method for estimating hydraulic pressure within and controlling a dry dual clutch transmission

A transmission control module for a vehicle transmission includes a gear determination module, a predictive shift module, and a validation module. The gear determination module commands a first shift configuration based on an actual pedal position. The predictive shift module calculates a predicted pedal position based on the actual pedal position and commands a second shift configuration based on the predicted pedal position. The validation module validates the predicted pedal position and selectively cancels the second shift configuration based on the validation.

Accelerator pedal predictive shift point control

A vehicle includes an engine that shuts down and restarts at idle, a dual-clutch transmission (DCT) having a controller and two input clutches for connecting the engine to respective evenly and oddly numbered gears of the DCT. The controller has a shift algorithm for shifting the DCT to achieve a predetermined engine load state during an engine autostart/autostop cycle, with the load state being unloaded or partially loaded. A DCT for the vehicle includes the input clutches and controller. A method includes shifting the DCT to the predetermined engine load state while the engine is off and an engine restart is commanded, and restarting the engine in the engine load state. The method may also include maintaining the clutches at a first point relative to a kiss point of the input clutches when the load state is unloaded, and at a second point when the load state is partially loaded.

Method and apparatus for clutch control in a vehicle having an engine start-stop powertrain and a dual-clutch transmission

A control system for determining a desired gear ratio of an automatic transmission includes a pedal rate module that determines a pedal rate of an accelerator pedal, and a shift module that determines the desired gear ratio of the transmission based on a position of the accelerator pedal and the pedal rate. The shift module determines the desired gear ratio based on a comparison of the pedal rate and a predetermined rate. The predetermined rate is based on a first period since the transmission shifted into a current gear. The shift module also determines the desired gear ratio based on one of a second period the pedal rate remains less than a positive rate and a third period the pedal rate remains greater than a negative rate. A related control method is also provided.

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Milford, MI, United States of America

John E Marano