Gm Global Technolgoy Operations, Inc.

Matthew D Whitton

Steven Patrick Moorman

Robert L Williams

Craig J Hawkins

Xuefeng Tim Tao

Christopher Jay Weingartz

Mark A Schang

Jonathan P Kish

Christopher E Whitney

Brian M Porto

Ronald W Van Diepen

Harinath Atmaram

Timothy R Stockdale

Mateusz M Nowak

Richard I Chang

Matthew Kempeinen

John William Boughner

Alfonso G Hysko

Fei An

Ning Jin

Todd R Berger

Keith D Van Maanen

Joel H Gunderson

Adam J Heisel

Christopher Harold Knieper

Crystal Nassouri

Dara Monajemi

Nathaniel E Wilke

David Chris Webert

Colin Hultengren

Roberto Diaz

Kurt J Mitts

Roger Joseph Rademacher

Cheol W Kim

James L Abington

Amanda P Igel

Daniel Deras

Brandon E Hancock

Mark A Yacoub

Shashikanth Rangaraju

Paul R Peterson

Methods and systems are provided for generating a predictive tachometer profile at a tachometer of a vehicle. When an inertia phase of a transmission shift event is determined to be in progress, the predictive tachometer profile can be computed based on: a computed shift completion percentage; a difference between the current attained gear speed and the commanded gear speed; and a commanded engine torque that is determined based on the accelerator pedal position and the vehicle speed. The predictive tachometer profile can then be displayed at the tachometer. The predictive tachometer profile accounts for delays in a signal path between an engine speed sensor and the tachometer.

Predictive tachometer profile generation during transmission shift events

Methods and systems are provided for generating a predictive tachometer profile at a tachometer of a vehicle. An engine speed offset can be generated based on an engine acceleration and an accelerator pedal position rate. A predictive tachometer profile displayed at the tachometer can then be generated based on the engine speed offset and an actual engine speed.

Predictive tachometer profile generation during idle revving events

A transmission is provided having a control module, an input member, an output member, four planetary gear sets, a plurality of interconnecting members, and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The control module includes a control logic sequence for performing a coasting downshift of the transmission.

Multi-speed transmission and method of control

A system for a vehicle includes a desired pressure module, a valve actuation module, a filter module, and a capacity detection module. The desired pressure module selectively generates an increase in a desired pressure of hydraulic fluid for a clutch of an automatic transmission. The valve actuation module actuates a solenoid valve based on the desired pressure. The solenoid valve supplies hydraulic fluid to a regulator valve, and the regulator valve supplies hydraulic fluid to the clutch. The filter module filters an acceleration of a shaft of the automatic transmission to generate a filtered acceleration. The capacity detection module indicates whether the clutch reached torque carrying capacity based on the filtered acceleration.

Clutch capacity detection systems and methods

A vehicle includes an engine, dual-clutch transmission (DCT), and controller. The controller executes a method to control a requested change-of-mind shift of the DCT to a second desired gear state. The requested shift is initiated after a prior-requested but not yet fully-executed shift of the DCT to a first desired gear state. The controller detects the requested shift, identifies the second desired gear state, and aborts the prior-requested shift immediately upon identifying the second desired gear state. The controller also shifts the DCT to the second desired gear state using a calibrated shift profile corresponding to the detected shift. The calibrated shift profile describes required oncoming and offgoing clutch torques needed for achieving the second desired gear state. Engine speed control may be used to synchronize engine and input shaft speeds.

Change-of-mind shift control of a dual-clutch transmission

A method of controlling a clutch-to-clutch power-on upshift of a transmission includes defining a possible engine torque as a latched possible engine torque value. An on-coming clutch torque phase target value is defined as a latched on-coming clutch torque value, and held constant until a final ramp. A commanded engine torque is reduced and maintained to a maximum torque reduction value until a shift completion ratio is achieved. The commanded engine torque is increased until the commanded engine torque is equal to a restore ramp target value. Both the on-coming clutch torque and the commanded engine torque are simultaneously increased at a final ramp rate, such that the increase in the on-coming clutch torque parallels the increase in the commanded engine torque, until an actual engine torque is substantially equal to the possible engine torque, to complete the shift.

Method of controlling a vehicle during a clutch-to-clutch power upshift of a transmission

A method of controlling a transmission includes selecting a target speed of a second shaft, and measuring a second speed of the second shaft and an output speed of an output shaft. The method includes detecting a rolling neutral condition wherein a first and second clutch are uncoupled from a torque generator and a synchronizer is mated to a predicted gear to apply a load in a direction, and one of a first condition wherein the output speed is decreasing and the target speed is less than the second speed and a second condition wherein the output speed is increasing and the target speed is less than the second speed. The method then includes translating the synchronizer away from the predicted gear, coupling and decoupling the second clutch to and from the torque generator, and mating the synchronizer to the predicted gear to again apply the load in the direction.

Method of controlling a transmission

A method of executing a downshift in a fixed-gear powertrain having an input node and an output node related by a starting speed ratio before the downshift and a finishing speed ratio after is provided. The downshift includes a torque phase and an inertia phase. A starting output torque is calculated as a function of a starting driver request. An electric machine applies a starting regenerative input torque which is calculated as substantially equal to the starting output torque divided by the starting speed ratio. A finishing output torque is calculated as a function of a finishing driver request. The electric machine applies a finishing regenerative input torque which is calculated as substantially equal to the finishing output torque divided by the finishing speed ratio.

Negative-torque downshift execution for fixed-gear transmissions

A vehicle includes an engine, dual-clutch transmission (DCT), and controller. The controller executes a method to detect a requested power-on downshift of the DCT from an attained gear to a desired gear. Offgoing and oncoming clutches are identified for the power-on downshift from the input clutches, and the controller determines whether engine speed has reached a target synchronous speed. The controller increases oncoming clutch torque at a calibrated ramp rate when a fork for the desired gear has engaged and releases the offgoing clutch at another calibrated ramp rate. If engine flare is present, the controller adjusts the oncoming clutch ramp rate, uses engine torque management to control the flare, and allows the offgoing clutch to continue disengaging. The power-on downshift is completed when the oncoming clutch reaches full torque capacity of the engine and the offgoing clutch is completely exhausted.

Power-on downshift control of a 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.

Upshift control of a dry dual-clutch transmission

A vehicle includes an engine, an engine control module (ECM), and a dual clutch transmission (DCT) assembly. The DCT assembly has first and second input clutches, first and second gear sets selectively connected to the engine via the respective first and second input clutches, and a transmission control module (TCM). In executing a launch control method, the TCM receives a launch request, receives an actual engine torque, and determines the inertia and acceleration of the engine. The TCM then calculates a clutch torque for the particular input clutch used for vehicle launch as a function of the actual engine torque and the product of the inertia and the acceleration, compares the calculated clutch torque to the commanded clutch torque, modifies a torque-to-position (TTP) table depending on the comparison result, and transmits a clutch position signal to the designated input clutch to command an apply position extracted from the TTP table.

Dual clutch transmission vehicle launch control

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.

Dual-clutch transmission thermal management

A method of commanding a synchronous gear shift begins by receiving a request to shift from a third gear to a first gear, and skipping a second gear having a gear ratio between the gear ratio of the first gear and the gear ratio of the third gear. Subsequently the method includes: reducing a torque command to a predetermined value; opening a clutch disposed on the input shaft of the transmission to decouple the transmission from the engine; transitioning the engine from a torque-control mode into a speed-control mode; commanding the engine to rotate at a speed dictated by the motion of the vehicle and the gear ratio of the first gear; closing the clutch to couple the transmission and the engine; and transitioning the engine back into the torque-control mode.

Automatic transmission synchronous gear shift

A method of adjusting a pressure signal to an actuator piston to control movement of a synchronizer actuator fork of a transmission includes moving the synchronizer actuator fork from a start position into a target position by applying an initial fluid pressure value. The time required to move the synchronizer actuator fork is measured to define a measured actuation time, and compared to a target actuation time. A correction factor is applied to the initial fluid pressure value to define a revised fluid pressure value when the measured actuation time is not within a pre-defined time range of the target actuation time. When the measured actuation time is greater than the pre-defined time range of the target actuation time, the initial fluid pressure value is increased. When the measured actuation time is less than the pre-defined time range of the target actuation time, the initial fluid pressure value is decreased.

Method of controlling a synchronizer actuator fork of a transmission

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.

Growing community of inventors

Howell, MI, United States of America

Matthew D Whitton