Gm Global Technolgoy Operations, Inc.

Dara Monajemi

Matthew Pruski

Brian H Fiore

Brian M Porto

Jeremy V Horgan

Matthew D Whitton

Randall B Dlugoss

Todd Thor

Joel H Gunderson

David Chris Webert

Brian James Pellerito

Kristopher J Kokko

Mark David Kieliszewski

John Jancowski-Walsh

Amanda P Igel

Zhuoran Zhang

A method and system of controlling a drive-neutral-drive (D-N-D) shift in a multi-speed transmission. The method includes receiving a drive to neutral (D-N) shift request followed by a neutral to drive (N-D) shift request; initiating a drive to neutral (D-N) shift and determining an attained gear; determining a scheduled gear; determining if the scheduled gear is equal to the attained gear; and determining whether an off-going clutch for the drive to neutral (D-N) shift is in a hold state. The method further includes (I) aborting the drive to neutral (D-N) shift when (i) the scheduled gear is not equal to the attained gear and (ii) the off-going clutch for the (D-N) shift is in the hold state, or (II) completing a shift to neutral (N) when the off-going clutch for (D-N) shift is not in the hold state followed by shifting back drive (D).

Method and system of controlling a quick succession drive-neutral-drive (D-N-D) shift

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 includes a torque converter having a turbine, a transmission having friction clutches and an input member connected to the turbine, and a controller. The controller is programmed to control a change-of-mind shift maneuver of the transmission. By executing a method, the controller detects the change-of-mind shift maneuver, predicts an acceleration profile of the turbine for a next-requested shift of the detected shift maneuver as a function of a calibrated desired shift time and an output speed of the transmission, calculates a shift control value for a next-requested shift of the shift maneuver using the predicted acceleration profile, and executes the next-requested shift via the clutches using the calculated shift control value. The shift maneuver may be a skip-at-sync quick shift-to-quick shift or power downshift-to-power downshift. The shift value may be a clutch pressure for an offgoing holding clutch or a torque management level from an engine.

Predictive control of a change-of-mind-shift maneuver

A transmission for a vehicle having a prime mover with an output shaft. The transmission includes an offgoing clutch that is selectively connected to the output shaft, and a controller in communication with the prime mover. The controller includes an offgoing clutch control module that determines an offgoing clutch torque profile at the start of a torque phase in a power downshift that does not exceed a predetermined offgoing clutch energy threshold and a torque request module that limits a rate of input torque into the transmission from the prime mover based upon the determined offgoing clutch torque profile.

System and method for controlling vehicle components during a power downshift

A method for monitoring a fixed-gear transmission includes deriving a node speed relationship for each of the planetary gear sets based upon a center distance and a gear ratio and determining equivalent speed parameters for nodes of the planetary gear sets based upon a transmission input speed state, an intermediate node speed state and a transmission output speed state. A clutch slip speed relationship is determined for each of the clutches based upon the node speed relationships for the planetary gear sets and the equivalent speed parameters for nodes of the planetary gear sets. Rotational speed sensors monitor the input transmission speed, the intermediate node speed and the transmission output speed. A clutch slip speed for each of the clutches is determined based upon the respective clutch slip speed relationship and the monitored input transmission speed, the monitored intermediate node speed and the monitored transmission output speed.

Transmission node speed monitoring

A method of controlling clutches in a multi-speed transmission includes beginning a current shift from a starting gear to an initial target gear, and determining whether the current shift is a downshift. The method determines jump-stage eligibility of a first clutch. Determining jump-stage eligibility includes determining whether the first clutch is a holding clutch for the current shift, and determining whether the first clutch is an off-going clutch for a legal shift from the initial starting gear to an adjusted target gear having a higher speed ratio than the initial starting gear. If the first clutch is not jump-stage eligible, the method maintains pressure of the first clutch at a current pressure. If the first clutch is jump-stage eligible, the method reduces the pressure of the first clutch from the current pressure to a staging pressure, which is greater than a slipping pressure.

Power downshift clutch control

A vehicle includes a prime mover, input clutch, transmission, and controller. The transmission, which is selectively connected to the output shaft via the input clutch, has multiple friction clutches, including respective offgoing and oncoming clutches for a negative torque upshift. The controller includes a torque request module, offgoing clutch module, and oncoming clutch module. The torque request module limits input torque into the transmission during the negative torque upshift. The offgoing control module determines actual offgoing clutch torque capacity of the offgoing clutch, calculates an actual offgoing clutch pressure using the actual offgoing clutch torque capacity, and controls the offgoing clutch through the shift using the actual offgoing clutch pressure. The oncoming control module controls the oncoming clutch through multiple stages of control of the oncoming clutch, including a fill, staging, ramp, and quick-lock stage. Closed-loop pressure correction is provided via PID logic through the inertia and torque shift phases.

Negative torque upshift control

A vehicle transmission includes a plurality of oncoming clutches that are hydraulically-actuated. A controller is operatively connected to the plurality of oncoming clutches. An algorithm stored on and executable by the controller causes the controller to determine if at least one predefined coast condition is met and identify the plurality of oncoming clutches configured to be engageable during a downshift event from an initial gear ratio to respective other gear ratios. The initial gear ratio is greater than each of the respective other gear ratios. The algorithm causes the controller to generate a first pressure command to at least partially pressurize a first one of the oncoming clutches to a first staging pressure (P) if the at least one predefined coast condition is met prior to the downshift event. The first staging pressure (PS) is defined as a first return spring pressure (P) minus a first variable correction factor (CF).

Partial prefill of clutch for coast downshift conditions in a vehicle

A vehicle includes an engine, an engine control module (ECM), and a transmission assembly. The transmission assembly includes a transmission control module (TCM), a stationary member, gear sets, an input member connected to the engine and one of the gear sets, and a binary clutch assembly. The binary clutch assembly has a freewheeling element and a binary device preventing rotation of the binary clutch assembly when applied, and allows the binary clutch assembly to freewheel when released. The TCM controls a slip speed differential of the binary clutch assembly when the vehicle is coasting in a forward gear state. The TCM determines a threshold maximum slip speed differential, calculates a required engine speed for achieving no more than the threshold maximum, and transmits the required engine speed to the ECM to maintain engine speed at or above the required engine speed. Doing so enables transmission state and direction change flexibility.

Slip control of a binary clutch assembly

A method for controlling the torque phase of a clutch-to-clutch power downshift in a vehicle includes determining, during a near-sync boost (NSB) state of the power downshift, a synchronization speed. The method includes estimating, via a controller, a feed-forward clutch pressure that holds a speed of the turbine at the synchronous speed, and then ramping a clutch pressure command to the oncoming clutch to the calculated feed-forward clutch pressure. Closed-loop proportional-integral-derivative (PID) control is initiated over the clutch pressure command during the NSB phase in response to a predetermined PID activation event. A vehicle includes an engine, transmission, torque converter, and a controller. The controller has a processor and memory on which instructions embodying the above method are recorded. Execution of the instructions by the processor causes the controller to execute the method.

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Lansing, MI, United States of America

Dara Monajemi