Self-diagnosing pressure regulator apparatus
AssigneeGeneral Motors Corporation
InventorsCharles Francis Long, Michael Leo Duhaime, Martin Robert Dadel
Life of this patent
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Abstract
An improved and self-diagnosing shift pressure regulator apparatus for an automatic shift transmission provides a diagnostic output that reliably and timely detects initiation and cessation of fluid supply to a friction element. The regulator apparatus includes a pressure regulator valve responsive to an electronically developed pilot pressure, and a diagnostic switch. The pilot pressure positions the pressure regulator valve in one of three states—ON, TRIM, and OFF—and the diagnostic switch is continuously activated by a control pressure whenever the pressure regulator valve is in the TRIM or ON states.
Claims10
A self-diagnosing pressure regulator apparatus for supplying a regulated fluid pressure to a hydraulic element in relation to a trim pressure, comprising:
- a pressure regulating valve spool axially positionable within a valve bore, the valve spool having first and second opposed pressure control areas and spaced lands defining first and second fluid chambers between said lands, said hydraulic element being continuously coupled to said first fluid chamber;
- a pressure-responsive diagnostic switch being continuously coupled to said second fluid chamber;
- first and second fluid pressure passages and first and second exhaust passages selectively coupled to said first and second fluid chambers, respectively, depending on the position of said valve spool within said valve bore, said first and second fluid pressure passages containing first and second fluid pressures, and said exhaust passages containing an exhaust pressure;
- and
- a trim passage for directing said trim pressure to the first pressure control area, and a spring and hydraulic element feedback pressure acting on the second pressure control area, whereby said valve spool is positioned within said valve bore in response to said trim pressure, said spring and said feedback pressure to establish one of:
- (1) an OFF state in which fluid in said first and second fluid chambers is exhausted through said first and second exhaust passages and said diagnostic switch detects a deactivated state of said valve spool in response to said exhaust pressure, (2) a TRIM state in which fluid in said first chamber is regulated in relation to said trim pressure, said second chamber is continuously coupled to said second fluid pressure passage, and said diagnostic switch detects an activated state of said valve spool in response to said second fluid pressure and (3) an ON state in which said first chamber is continuously coupled to said first fluid pressure passage, said second chamber is continuously coupled to said second fluid pressure passage, and said diagnostic switch detects an activated state of said valve spool in response to said second fluid pressure.
A self-diagnosing pressure regulator apparatus for supplying a regulated fluid pressure to a hydraulic element in relation to a trim pressure, comprising:
- a pressure-responsive diagnostic switch;
- a pressure regulator valve having a valve bore and a spool with axially spaced lands that is axially positionable within said valve bore, the spaced lands defining a first fluid chamber continuously coupled to said hydraulic element and a second fluid chamber continuously coupled to said diagnostic switch;
- and
- said spool being positioned in said valve bore in response to said trim pressure to establish one of:
- (1) an OFF state in which said first and second fluid chambers are exhausted and said diagnostic switch detects a deactivated state of said spool in response to an exhaust pressure in said second fluid chamber;
- (2) a TRIM state in which fluid is supplied to said hydraulic element through said first fluid chamber and partially pressurized based on said trim pressure, said second chamber is continuously coupled to a control pressure, and said switch detects an activated state of said spool in response to said control pressure;
- and (3) an ON state in which said first chamber and said hydraulic element are fully pressurized, said second chamber is continuously coupled to said control pressure, and said diagnostic switch detects an activated state of said spool in response to said control pressure.
Dependencies are inferred from the claim text.