Dara Monajemi

8510005, Aug 13, 2013

Jul 19, 2012

13/552972

Dara Monajemi - Lansing MI, US
Mark David Kieliszewski - Lake Orion MI, US
Todd J. Thor - Byron MI, US

GM Global Technology Operations LLC - Detroit MI

G07F 7/00

701 67

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.

20210078583, Mar 18, 2021

Sep 17, 2019

16/573268

- Detroit MI, US
Zhuoran Zhang - Ann Arbor MI, US
Dara Monajemi - Lansing MI, US

B60W 30/19
B60W 10/11
B60W 10/02
F16H 61/02
F16H 61/16
F16H 61/682

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).

20160076643, Mar 17, 2016

Sep 15, 2014

14/486481

- Detroit MI, US
Dara Monajemi - Lansing MI, US
Brian H. Fiore - Waterford MI, US
Joel H. Gunderson - Canton MI, US

F16H 61/12
F16H 63/50
F16H 61/686

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.

20150032341, Jan 29, 2015

Jul 24, 2013

13/949295

- Detroit MI, US
Dara Monajemi - Lansing MI, US
David C. Webert - Livonia MI, US
Amanda P. Igel - Howell MI, US

GM GLOBAL TECHNOLOGY OPERATIONS LLC - Detroit MI

F16D 48/06
B60W 10/10
B60W 10/02

701 53

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).