Abstract: A minimum pressure shut-off valve closes off fuel flow responsive fuel pressure being below a predefined pressure. A sleeve includes at least a first flow window and a second flow window. The second window includes a notch providing a flow area based on an axial position of a spool moveable within the sleeve.

Abstract: A pressure regulating valve includes a housing having a valve inlet and a valve outlet. A movable piston is located in the housing, and a position of the piston is determined by a selected difference between and inlet pressure and an outlet pressure. The movable piston at least partially defines one or more flow channels between the valve inlet and the valve outlet. When the movable piston is in a fully open position, an axial inlet opening at an inlet end of the one or more flow channels is smaller than an radial depth of the one or more flow channels at the inlet end of the one or more flow channels.

Abstract: An example bypass valve includes a sleeve providing a bore that extends along an axis. The sleeve has at least one window. The bypass valve also includes a spool received within the bore. The spool is configured to move within the bore between a first position that restricts flow through at least one window and a second position that permits flow through the at least one window of the sleeve. An outer diameter of the spool is from 99.90 to 99.95 percent of a diameter of the bore.

Abstract: In one featured embodiment, a sleeve for a valve includes a sleeve body surrounding a center axis and defined by an overall length extending from a first end to a second end. The sleeve body has a central bore extending from the first end to the second end. The central bore has a first surface portion comprising a piston contact surface that is defined by a first inner diameter, wherein the piston contact surface is configured to slide against a piston to be received within the central bore. In one example, a ratio of the overall length to the first inner diameter is between 3.51 and 3.63.

Abstract: A pressure regulating valve assembly includes a pressure regulating valve sleeve and a pressure regulating valve spool. The pressure regulating valve sleeve includes a first window set and a second window set. The pressure regulating valve spool includes a first cylindrical portion, a second cylindrical portion, and a third cylindrical portion formed between the first and second cylindrical portions. The pressure regulating valve spool also includes an angled bucket formed on the first cylindrical portion having a high gain portion of a first width, a low gain portion of a second width, and a ratio of the first width to the second width between 1.44 and 1.47. The pressure regulating valve spool further includes an angled outlet surface. The angled bucket is configured to align with the first window set and the angled outlet surface is configured to align with the second window set.

Abstract: A pressure regulating valve includes a housing having a valve inlet and a valve outlet. A movable piston is located in the housing, and a position of the piston is determined by a selected difference between and inlet pressure and an outlet pressure. The movable piston at least partially defines one or more flow channels between the valve inlet and the valve outlet. When the movable piston is in a fully open position, an axial inlet opening at an inlet end of the one or more flow channels is smaller than an radial depth of the one or more flow channels at the inlet end of the one or more flow channels.

Abstract: A minimum pressure shut-off valve closes off fuel flow responsive fuel pressure being below a predefined pressure. A sleeve includes at least a first flow window and a second flow window. The second window includes a notch providing a flow area based on an axial position of a spool moveable within the sleeve.

Abstract: An example bypass valve includes a sleeve providing a bore that extends along an axis. The sleeve has at least one window. The bypass valve also includes a spool received within the bore. The spool is configured to move within the bore between a first position that restricts flow through at least one window and a second position that permits flow through the at least one window of the sleeve. An outer diameter of the spool is from 99.90 to 99.95 percent of a diameter of the bore.

Abstract: A pressure regulating valve assembly includes a pressure regulating valve sleeve and a pressure regulating valve spool. The pressure regulating valve sleeve includes a first window set and a second window set. The pressure regulating valve spool includes a first cylindrical portion, a second cylindrical portion, and a third cylindrical portion formed between the first and second cylindrical portions. The pressure regulating valve spool also includes an angled bucket formed on the first cylindrical portion having a high gain portion of a first width, a low gain portion of a second width, and a ratio of the first width to the second width between 1.44 and 1.47. The pressure regulating valve spool further includes an angled outlet surface. The angled bucket is configured to align with the first window set and the angled outlet surface is configured to align with the second window set.

Abstract: A metering valve assembly includes a metering valve sleeve and a metering valve spool. The metering valve sleeve includes an inlet window set and an outlet window set with a first outlet window having a first logarithmic contour and a second outlet window having a second logarithmic contour. A ratio of an inner width of the first outlet window to an inner length of the first outlet window is between 1.48 and 1.52. A ratio of an inner width of the second outlet window to an inner length of the second outlet window is between 2.21 and 2.29. The metering valve spool includes first, second, and third cylindrical portions. The metering valve spool is configured to move bi-directionally along a longitudinal axis of the metering valve sleeve and control fluid flow between the inlet window set and the outlet window set relative to the first, second, and third cylindrical portions.