Allison Transmission, Inc.

John W E Fuller

Charles Francis Long

Darren J Weber

An apparatus and method are disclosed for controlling fluid flow to a variator which responsive to separate high and low pressure fluids to control an output torque thereof. A first trim valve may be responsive to a first control signal to supply a first fluid at a fluid outlet thereof. A second trim valve may be responsive to a second control signal to supply a second fluid at a fluid outlet thereof. A variator switching sub-system may controllably supply the high pressure fluid and the low pressure fluid to the variator. A multiplex valve may be fluidly coupled to the outlets of the first and second trim valves, and may supply the first fluid as the high pressure fluid to the variator switching sub-system during at least one predefined operating condition and may otherwise supply the second fluid as the high pressure fluid to the variator switching sub-system.

Variator multiplex valve scheme for a torroidal traction drive transmission

An apparatus and method are disclosed for controlling fluid flow in a motor vehicle transmission. At least one friction engagement device is fluidly coupled to a first pump, and a lubrication and cooling sub-system is normally fluidly coupled to a second pump. Illustratively, when a flow rate of the fluid in the first fluid passageway is less than a threshold fluid flow rate, a temperature of the fluid is greater than a temperature threshold and a fluid flow demand is greater than a fluid flow demand threshold, fluid flow from the second pump to the lubrication and cooling sub-system is blocked and fluid supplied by the second pump is instead directed to the at least one friction engagement device such that fluid is supplied by both the first and second pumps only to the at least one friction engagement device.

Dual pump regulator system for a motor vehicle transmission

An apparatus for controlling a variator having at least one roller between two torroidal disks may include at least one actuator responsive to fluid pressure at separate high side and low side fluid inlets thereof to control torque applied by the at least one roller to the disks. First and second variator switching valves may each receive a first fluid at a first pressure and a second fluid at a second lesser pressure. The first and second variator switching valves supply the first fluid to the high side fluid inlet and the second fluid to the low side fluid inlet during two of four different operational states together defined by the variator switching valves, and supply the second fluid to the high side fluid inlet and the first fluid to the low side fluid inlet during each of the remaining two of the four different operational states.

Variator switching valve scheme for a torroidal traction drive transmission

An apparatus for controlling a variator having at least one roller between two toroidal disks may include at least one actuator responsive to fluid pressure at separate high side and low side fluid inlets thereof to control torque applied by the at least one roller to the disks. First and second variator switching valves may each receive a first fluid at a first pressure and a second fluid at a second lesser pressure. The first and second variator switching valves supply the first fluid to the high side fluid inlet and the second fluid to the low side fluid inlet during two of four different operational states together defined by the variator switching valves, and supply the second fluid to the high side fluid inlet and the first fluid to the low side fluid inlet during each of the remaining two of the four different operational states.

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Preston, United Kingdom

John W E Fuller