Abstract: A vehicle powertrain hydraulic system (10) includes a clutch (12), a piston (62) disposed in a cylinder (60) to drive a shift selector (14), a pump (82) in fluid communication with a fluid supply (86) to pressurize fluid, and first and second fluid pressure lines (91, 92) from the pump to first and second sides of the piston. A third fluid pressure line (93) may extend to the clutch from the cylinder in a location between the first and second sides of the piston, such that the piston also may be a valve to control fluid flow to the clutch. The pump may be reversible and coupled to an electric motor (80), and a centrifugal regulator (84) may be coupled to the motor and in fluid communication with the first and second pump pressure lines to regulate fluid pressure therein. A related operational method is also disclosed.

Abstract: A vehicle powertrain hydraulic system (10) includes a clutch (12), a piston (62) disposed in a cylinder (60) to drive a shift selector (14), a pump (82) in fluid communication with a fluid supply (86) to pressurize fluid, and first and second fluid pressure lines (91, 92) from the pump to first and second sides of the piston. A third fluid pressure line (93) may extend to the clutch from the cylinder in a location between the first and second sides of the piston, such that the piston also may be a valve to control fluid flow to the clutch. The pump may be reversible and coupled to an electric motor (80), and a centrifugal regulator (84) may be coupled to the motor and in fluid communication with the first and second pump pressure lines to regulate fluid pressure therein. A related operational method is also disclosed.