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US 7,395,837 B2Granted
Multiplexed pressure switch system for an electrically variable hybrid transmission
AssigneeGeneral Motors Corporation
InventorsMichael D. Foster, Charles F. Long
Life of this patent
Estimating the term…
Abstract
A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low and high speed mode, an electrically variable low and high speed mode, and a hill hold mode. The electro-hydraulic control system includes a multiplexed pressure switch system. The multiplexed pressure switch system of the present invention allows position detection of six torque transmitting mechanism control valves through the use of only four pressure switches.
Claims19
A pressure switch diagnostic system for an electrically variable hybrid transmission comprising:
- a plurality of trim valves each having a first and a second position;
- a plurality of pressure sensitive switches, having a high and a low logic state, each in selective fluid communication with one of said plurality of trim valves;
- wherein each of said plurality of pressure sensitive switches are operable to detect a change from said first to said second position or a change from said second to said first position of its respective one of said plurality of trim valves and accordingly each of said plurality of pressure switches will report one of said high or said low logic state;
- and
- at least one logic valve in selective fluid communication with at least one of said plurality of trim valves such that at least one of said plurality of pressure sensitive switches are operative to detect changes in said at least one logic valve without requiring an additional pressure sensitive switch to detect a change in position of said at least one logic valve.
2 more elements
A pressure switch diagnostic system for an electrically variable hybrid transmission comprising:
- a first trim valve, having a first position and a second position, in selective fluid communication with a first pressure sensitive switch, wherein said first pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said first trim valve;
- a second trim valve, having a first position and a second position, in selective fluid communication with a second pressure sensitive switch, wherein said second pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said second trim valve;
- a third trim valve, having a first position and a second position, in selective fluid communication with a third pressure sensitive switch, wherein said third pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said third trim valve;
- a first logic valve, having a first position and a second position, disposed in selective fluid communication with each of said first trim valve and said second trim valve;
- and
- a second logic valve, having a first position and a second position, disposed in selective fluid communication with said third trim valve.
- wherein said first, second, and third trim valves and said first, second, and third pressure sensitive switches and said first and second logic valve are connected in a multiplexed arrangement such that there are fewer of said pressure sensitive switches than the sum of said trim valves and said logic valves.
4 more elements
A pressure switch diagnostic system for an electrically variable hybrid transmission comprising:
- a first trim valve, having a first position and a second position, in selective fluid communication with a first pressure sensitive switch, wherein said first pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said first trim valve;
- a second trim valve, having a first position and a second position, in selective fluid communication with a second pressure sensitive switch, wherein said second pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said second trim valve;
- a third trim valve, having a first position and a second position, in selective fluid communication with a third pressure sensitive switch, wherein said third pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said third trim valve;
- a fourth trim valve, having a first position and a second position, in selective fluid communication with a fourth pressure sensitive switch, wherein said first pressure sensitive switch is operable to detect and report a change from said first to said second position or said second to said first position of said fourth trim valve;
- a first logic valve, having a first position and a second position, disposed in selective fluid communication with each of said first trim valve and said second trim valve;
- a second logic valve, having a first position and a second position, disposed in selective fluid communication with said third trim valve;
- wherein said first pressure sensitive switch and said second pressure sensitive switch are operable to detect a change from said first to said second position or said second to said first position of said first logic valve irrespective of the position of said first trim valve and said second trim valve;
- wherein said third pressure sensitive switch is operable to detect a change from said first to said second position or said second to said first position of said second logic valve when said third trim valve is in said first position;
- and
- wherein said third pressure sensitive switch is operable to detect a change from said first to said second position or said second to said first position of said third trim valve when said second logic valve is in said second position.
7 more elements
Dependencies are inferred from the claim text.