Allison Transmission, Inc.

Gm Global Technolgoy Operations, Inc.

Bryan H Hagelskamp

Charles Francis Long

Eric S Tryon

Jeffrey E Shultz

Elizabeth P Dick

An electro-hydraulic control system for a multispeed transmission having a plurality of torque-transmitting mechanisms includes a controller for operably controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having pressure control solenoids and trim valves. The system may also include one or more shift valves disposed in fluid communication with the fluid source and being capable of moving between stroked and de-stroked positions. In any given range, only two of the plurality of torque-transmitting mechanisms may be applied. Moreover, three of the plurality of pressure control solenoids are normally high solenoids, and the remaining solenoids are normally low solenoids.

Control system and method thereof for multispeed transmission

A multi-speed planetary transmission is operable in at least nine forward speed ratios, at least one reverse speed ratio, and at least one neutral speed ratio. A hydraulic control system for the transmission includes a hydraulic default control system and is operable to a default configuration when a default condition occurs during operation of the transmission. The hydraulic control system defaults to a forward default gear ratio during operation of the transmission in a first forward speed ratio and defaults to a default neutral speed ratio during operation of the transmission in a reverse speed ratio when a default condition occurs. The default condition may be a transmission control module ('TCM') power failure.

Power off hydraulic default strategy

A control for a multi-speed automatic vehicle transmission includes electrical and hydraulic components, such as pressure control valve systems in fluid communication with shift valves and electrohydraulic actuators. The control includes electrohydraulic features configured to enable the transmission to respond to an electrical failure whether the transmission is in neutral, a reverse range, or one of a plurality of forward ranges.

Electro-hydraulic failure recovery control for dual clutch transmission

A control for a multi-speed automatic vehicle transmission is provided. Electrical and hydraulic components are provided, including pressure control or 'trim' valve systems in fluid communication with shift valves and electrohydraulic actuators to selectively engage and disengage the transmission clutches or other shift mechanisms. Pressure switches are provided for the trim valves and shift valves. The fluid connections between the trim valve systems and the shift valve systems are configured to reduce the total number of valves and fluid passages required and to reduce the size of at least one of the valves. Clutch blocking features are provided. Power off limp home and reduced engine load at stop features are provided in all forward ranges, and control of double transition shifts is also provided.

Electro-hydraulic control including blocking features for multi-speed automatic transmission

Electro-hydraulic control including blocking features for mulit-speed automatic transmission

An electro-hydraulic control system is provided for a transmission, which is preferably a countershaft transmission, that has a three-position dog clutch actuator valve to control the position of a three-position dog clutch. At least one of the positions of the dog clutch actuator valve is established by pressurized fluid directed to the dog clutch actuator valve by two logic valves, both of which are controlled to direct pressurized fluid elsewhere in the hydraulic control system, as well.

Electro-hydraulic control system with three-position dog clutch actuator valve

An electro-hydraulic control system is provided, preferably for a countershaft transmission, that uses logic valves to multiplex trim systems to more than one torque-transmitting mechanism, thereby minimizing the number of required components. Additionally, the electro-hydraulic control system preferably has more than one failure mode so that the transmission operates at a respective predetermined speed ratio in the event of an interruption in electrical power.

Electro-hydraulic control system with multiplexed trim valves for a transmission

An electro-hydraulic control system is provided with a diagnostic system that uses extensive multiplexing of pressure switches to reduce the number of required components. The control system includes a controller with a pressure switch diagnostic system having first, second, third and fourth pressure switches each having a high and a low logic state, first and second logic valves each movable between a respective first position and second position, and first, second, third and fourth trim valves each movable between a respective first position and second position. The pressure switches are multiplexed to report one of the high and low logic state to the controller in accordance with a relatively high and low fluid pressure, respectively, at different ones of the trim valves and logic valves, thereby enabling a determination of a change in or failure to change position of the respective the trim valves or logic valves.

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Carmel, IN, United States of America

Bryan H Hagelskamp