Solenoid-actuated valve arrangement for a limp-home mode of an automatic transmission

• US 4,887,491 A
• Filed: 04/29/1988
• Issued: 12/19/1989
• Est. Priority Date: 04/29/1988
• Status: Expired due to Fees

• Current Assignee: Chrysler Motors Corporation Highland Park MI
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Leising, Maurice B., Holbrook, Gerald L.
• Primary Examiner(s): Diehl, Dwight G.
• Application Number:
  US07/187,770
• Time in Patent Office: 599 Days
• Field of Search: 74/866, 74/867, 74/865, 74/868, 74/861
• US Class Current: 477/34
• CPC Class Codes: F16H 2061/0034 Accumulators for fluid pressure supply; Control thereof
• CPC Class Codes: F16H 2061/004 Venting trapped air from hydraulic systems venting of hydrostatic transmissions F16H61/4174; deaeration or removal of unsolved gas F15B21/044
• CPC Class Codes: F16H 2061/1204 for malfunction caused by simultaneous engagement of different ratios resulting in transmission lock state or tie-up condition lock state for braking F16H61/0059
• CPC Class Codes: F16H 2061/1208 with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 2061/122 Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1232 Bringing the control into a predefined state, e.g. giving priority to particular actuators or gear ratios
• CPC Class Codes: F16H 2061/1264 Hydraulic parts of the controller, e.g. a sticking valve or clogged channel
• CPC Class Codes: F16H 2061/1268 Electric parts of the controller, e.g. a defect solenoid, wiring or microprocessor
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 2061/1292 the failing part is the power supply, e.g. the electric power supply
• CPC Class Codes: F16H 2302/06 Determining timing parameters of shifting, e.g. start of shifting for smoothing gear shift F16H61/08
• CPC Class Codes: F16H 2306/00 Shifting
• CPC Class Codes: F16H 2306/42 Changing the input torque to the transmission
• CPC Class Codes: F16H 2312/08 Rocking
• CPC Class Codes: F16H 59/50 Inputs being a function of the status of the machine, e.g. position of doors or safety belts
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/686 with orbital gears
• CPC Class Codes: Y10S 477/906 Means detecting or ameliorating the effects of malfunction or potential malfunction

Abstract

A solenois-actuated valve arrangement in a four-speed automatic transmission having a structure in combination with the manual valve in the hydraulic circuit that will enable a limp-home mode or limited transmission operation, which will permit the vehicle to operate in park, neutral, second or reverse gear as desired in that absence of electrical power to the solenoid-actuated valves.

Claims

1. A fluid system in an electronically controlled vehicle transmission to allow the transmission to operate in a plurality of forward and reverse operating modes of a gear assembly in the absence of electrical power, said system comprising:

a pair of normally applied solenoid-actuated valve means controlling engagement and disengagement of at least one fluid actuating device and having a non-energized position for allowing fluid flow to at least one fluid actuating device in the absence of electrical power and an energized position for venting fluid flow to the at least one fluid actuating device in the presence of electrical power;

a pair of normally vented solenoid-actuated valve means controlling engagement and disengagement of at least one fluid actuating device and having a non-energized position for venting fluid flow to at least one fluid actuating device in the absence of electrical power and an energized position for allowing fluid flow to the at least one fluid actuating device in the presence of electrical power;

manually actuated valve means to command a predetermined operating mode; and

said normally applied solenoid-actuated valve means and said normally vented solenoid-actuated valve means being arranged such that in the absence of electrical power, said manually actuated valve means being moveable to switch the fluid flow between said normally applied and normally vented valve means to allow at least a pair of fluid actuating devices to selectively change the operating mode to allow the transmission to operate either in at least one forward or reverse operating modes.

2. A fluid system in an electronically controlled vehicle transmission to allow the transmission to operate in a plurality of forward and reverse operating modes of a gear assembly in the absence of electrical power, said system comprising:

a pump assembly for supplying fluid under pressure from a fluid source to at least one clutch apply piston;

a pair of normally applied solenoid-actuated valves controlling engagement and disengagement of at least one clutch apply piston and having a non-energized position for allowing fluid flow to the at least one clutch apply piston in the absence of electrical power and an energized position for venting fluid flow to the at least one clutch apply piston in the presence of electrical power;

a pair of normally vented solenoid-actuated valves controlling engagement and disengagement of at least one clutch apply piston and having a non-energized position for venting fluid flow to the at least one clutch apply piston in the absence of electrical power and an energized position for allowing fluid flow to the at least one clutch apply piston in the absence of electrical power;

a manually actuated valve to command a predetermined operating mode; and

said pair of normally applied and normally vented solenoid-actuated valves being arranged such that in the absence of electrical power, said manually actuated valve is manually moveable to switch the fluid flow between said normally applied and normally vented valves to allow a pair of clutch apply pistons to selectively change the operating mode of the gear assembly of the transmission to allow the transmission to operate in at least one forward or reverse operating mode.

3. Hydraulic system for an electronically controlled vehicle transmission having at least three forward gear ranges (1, 2, 3) and a reverse (R) range, and a system of clutch and brake means to control selective engagement of the gears of the transmission comprising:

a pressure pump and a pressure regulator means to supply pressurized hydraulic fluid under pressure to operate the clutch and brake means;

a manual valve means to command a predetermined gear range position;

an electronic controller having input signals applied thereto representative of engine and vehicle operating parameters and providing output signals to select the proper gears for operation of the vehicle as determined by said engine and vehicle operating parameters;

a pair of first solenoid-actuated valves controlling engagement of the respective clutch and brake means and normally in a position to connect hydraulic pressure fluuid to the respective clutch and brake means;

a pair of second solenoid-actuated valves controlling engagement of the respective clutch and brake means and normally in a position to vent hydraulic pressure fluid to the respective clutch and brake means; and

said pair of first and second solenoid-actuated valves being arranged such that in the absence of said output signals from said electronic controller, said manual valve means may be moved to switch fluid flow between said first or second solenoid-actuated valves to selectively allow the transmission to operate in at least one of the forward gear ranges and the reverse gear range.