Electronic transmission range selection subsystem in a hydraulic control system for an automatic transmission

Patent metadata

Field	Value
Publication number	US-9688257-B2
Application number	US-201414570329-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Dec 15, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A hydraulic control system for a transmission includes a source of pressurized hydraulic fluid, a park servo connected to a park mechanism, the park servo having a park side, an out-of-park side, and a biasing member disposed on the park side. A first valve assembly includes a first inlet port in fluid communication with the source of pressurized hydraulic fluid, a first outlet port, and a first valve for selectively allowing fluid communication between the first inlet port and the first outlet port. A second valve assembly includes a second inlet port in direct fluid communication downstream of the first valve assembly, a second outlet port in direct fluid communication with the out-of-park side of the park servo, and a second valve moveable between an out-of-park position and a park position.

First claim

The following is claimed:

1. A hydraulic control system for a transmission having a park mechanism, the hydraulic control system comprising:
a source of pressurized hydraulic fluid;
a park servo connected to the park mechanism, the park servo having a park side, an out-of-park side, and a biasing member disposed on the park side;
a first valve assembly having a first inlet port in fluid communication with the source of pressurized hydraulic fluid, having a first outlet port, and having a first valve for selectively allowing fluid communication between the first inlet port and the first outlet port;
a second valve assembly having a second inlet port in direct fluid communication downstream of the first valve assembly, having a second outlet port in direct fluid communication with the out-of-park side of the park servo, and having a second valve moveable between an out-of-park position and a park position, wherein the second valve allows fluid communication from the second inlet port to the second outlet port when in the out-of-park position and prohibits fluid communication from the second inlet port to the second outlet port when in the park position.

2. The hydraulic control system of claim 1 further comprising a first solenoid in selective fluid communication with the first valve assembly to selectively move the first valve, and a second solenoid in selective fluid communication with the second valve assembly to selectively move the second valve to the out-of-park position.

3. The hydraulic control system of claim 2 wherein the first solenoid and the second solenoid are normally low.

4. The hydraulic control system of claim 2 wherein the first solenoid and the second solenoid are normally high.

5. The hydraulic control system of claim 2 further comprising a park inhibit solenoid that selectively mechanically engages the park servo.

6. The hydraulic control system of claim 5 further comprising a transmission control module in electronic communication with the first and second solenoids.

7. The hydraulic control system of claim 6 wherein the park inhibit solenoid is not in electronic communication with the transmission control module.

8. The hydraulic control system of claim 2 wherein the second valve assembly further includes a third inlet port in fluid communication with the first outlet port of the first valve assembly and a third outlet port in fluid communication with the park side of the park servo, wherein the second valve prohibits fluid communication between the third inlet port and the third outlet port when in the out-of-park position and allows fluid communication between the third inlet port and the third outlet port when in the park position.

9. The hydraulic control system of claim 8 further comprising a third solenoid and a first check valve disposed between the third solenoid, the second solenoid, and the second valve assembly.

10. The hydraulic control system of claim 9 wherein the first solenoid, the second solenoid, and the third solenoid are normally low.

11. The hydraulic control system of claim 9 wherein the first solenoid and the second solenoid are normally high and the third solenoid is normally low.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Neelakantan Vijay A
• Mcdonough Joshua
• Knoth Matthew R
• Lundberg Philip C

Classifications

• B60T13/662

  characterised by specified functions of the control system components · CPC title

• B60T13/686 Primary

  in hydraulic systems or parts thereof · CPC title

• F16H2061/026

  On-off solenoid valve · CPC title

• F16H63/50

  Signals to an engine or motor · CPC title

• F16H61/0276

  Elements specially adapted for hydraulic control units, e.g. valves · CPC title