Patent Description:
Disclosed is a metering valve for a fuel metering unit as defined by claim <NUM>.

A detailed description of one or more embodiments of the disclosed apparatus are presented herein by way of exemplification and not limitation with reference to the Figures.

A fuel control system for a gas turbine engine may include a fuel metering unit that is arranged to regulate fuel flow from a fuel pump to the gas turbine engine. Referring to the Figures, the fuel metering unit may include a metering valve <NUM> having a valve housing <NUM>, a valve body <NUM> movably disposed within the valve housing <NUM>, a sensor <NUM> that is arranged to determine a position of the valve body <NUM>, and a controller <NUM>.

The valve housing <NUM> includes a housing wall <NUM> having an inner wall surface <NUM> and an outer wall surface <NUM> each disposed about a first axis <NUM>. The inner wall surface <NUM> defines a housing bore <NUM> that axially extends from a first valve housing end <NUM> towards a second valve housing end <NUM> along the first axis <NUM>.

The housing wall <NUM> defines a sensor bore or sensor opening <NUM> that extends along a second axis <NUM> that is disposed generally transverse to the first axis <NUM>. The sensor bore or the sensor opening <NUM> extends from the outer wall surface <NUM> to the inner wall surface <NUM>. The housing wall <NUM> further defines a bypass port <NUM> that is spaced apart from the sensor opening <NUM>. The bypass port <NUM> extends from the inner wall surface <NUM> to the outer wall surface <NUM>. The bypass port <NUM> extends along an axis that is disposed in a non-parallel and non-perpendicular relationship with respect to the first axis <NUM> and/or the second axis <NUM>.

The valve body <NUM> is arranged to move within the housing bore <NUM> of the valve housing <NUM> responsive to changes in fuel flow rate through the metering valve <NUM> based on a fuel level or the performance of the fuel pump operatively connected to the metering valve <NUM>. The valve body <NUM> is movable along the first axis <NUM> to selectively facilitate fuel flow through the bypass port <NUM> based on the amount of fuel flow provided through the metering valve <NUM> from the fuel pump.

The valve body <NUM> includes an outer surface <NUM> that extends between a first valve body end <NUM> and a second valve body end <NUM> along the first axis <NUM>. The valve body <NUM> defines a first bore <NUM> that extends from the first valve body end <NUM> towards the second valve body end <NUM> along the first axis <NUM>. The first bore <NUM> is arranged to receive a fuel flow from the fuel pump.

Referring to <FIG>, the valve body <NUM> defines a first recessed region <NUM> and a first window <NUM> that is defined within the first recessed region <NUM>. The first recessed region <NUM> radially extends inward (relative to the first axis <NUM>) from the outer surface <NUM> of the valve body <NUM> towards the first bore <NUM> and/or the first axis <NUM>. The first recessed region <NUM> includes a first face <NUM>, a second face <NUM> that is spaced apart from the first face <NUM>, and a first monitoring surface <NUM> that extends between the first face <NUM> and the second face <NUM>. The first face <NUM> and the second face <NUM> may be disposed generally parallel to each other or may be disposed in a non-parallel, non-perpendicular relationship with respect to each other and the first monitoring surface <NUM>. The first monitoring surface <NUM> is disposed generally parallel to the first axis <NUM>.

A first radial distance, d1, is defined between the first monitoring surface <NUM> and the outer surface <NUM> of the valve body <NUM>. The first radial distance corresponds to a depth of the first recessed region <NUM>.

The first window <NUM> is defined by or extends through the first monitoring surface <NUM>. The first window <NUM> extends along the second axis <NUM> through the valve body <NUM>. The first window <NUM> is fluidly connected to the first bore <NUM>. A fuel flow from the fuel pump may enter the first bore <NUM> and flow through the valve body <NUM> and a portion of the fuel flow may be bypassed such that the fuel flows through the first window <NUM> and out of the bypass port <NUM> based on a position of the valve body <NUM> relative to the bypass port <NUM>.

The first window <NUM> is selectively fluidly connected to the bypass port <NUM> based on the position of the first window <NUM> relative to the bypass port <NUM>. The valve body <NUM> may be in a first position that corresponds to a no fuel or low fuel condition in which fuel bypass flow from the first window <NUM> to the bypass port <NUM> is inhibited, as shown in <FIG>. While the valve body <NUM> is in the first position, the first window <NUM> is not in fluid communication with the bypass port <NUM> because the outer surface <NUM> of the valve body <NUM> blocks the bypass port <NUM>. The valve body <NUM> may be in a second position that corresponds to a medium fuel or non-maximum, non-minimum fuel condition facilitating a partial fuel bypass flow from the first window <NUM> to the bypass port <NUM>, as shown in <FIG>. While the valve body <NUM> is in the second position, the first window <NUM> is in partial fluid communication with the bypass port <NUM> because the outer surface <NUM> of the valve body <NUM> only partially blocks the bypass port <NUM>. The valve body <NUM> may be in a third position that corresponds to a maximum fuel condition facilitating a fuel bypass flow from the first window <NUM> to the bypass port <NUM>, as shown in <FIG>. While the valve body <NUM> is in the third position, the first window <NUM> is in fluid communication with bypass port <NUM> and the outer surface <NUM> of the valve body <NUM> is spaced apart from the bypass port <NUM>.

Referring to <FIG>, the valve body <NUM> defines the first recessed region <NUM> and a second recessed region <NUM>. The second recessed region <NUM> is axially spaced apart from the first recessed region <NUM> relative to the first axis <NUM>. The second recessed region <NUM> radially extends inward from the outer surface <NUM> towards the first axis <NUM> and/or the first bore <NUM>.

The second recessed region <NUM> includes a third face <NUM>, a fourth face <NUM> that is spaced apart from the third face <NUM>, and a second monitoring surface <NUM> that extends between the third face <NUM> and the fourth face <NUM>. The third face <NUM> and the fourth face <NUM> may be disposed generally parallel to each other or may be disposed in a non-parallel, non-perpendicular relationship with respect to each other and the second monitoring surface <NUM>. The second monitoring surface <NUM> is disposed generally parallel to the first axis <NUM> and the first monitoring surface <NUM>.

The first window <NUM> may be defined by or extends through at least one of the first monitoring surface <NUM> and/or the second monitoring surface <NUM>.

A second radial distance, d2, is defined between the second monitoring surface <NUM> and the outer surface <NUM> of the valve body <NUM>. The second radial distance corresponds to a depth of the second recessed region <NUM>. The first radial distance is greater than the second radial distance.

The valve body <NUM> may be in a first position that corresponds to a no fuel or low fuel condition in which fuel bypass flow from the first window <NUM> to the bypass port <NUM> is inhibited, as shown in <FIG>. While the valve body <NUM> is in the first position, the second monitoring surface <NUM> is at least partially aligned with the sensor opening <NUM> and the first window <NUM> is not in fluid communication with the bypass port <NUM> because the outer surface <NUM> of the valve body <NUM> blocks the bypass port <NUM>. The valve body <NUM> may be in a second position that corresponds to a maximum fuel condition facilitating a fuel bypass flow from the first window <NUM> to the bypass port <NUM>, as shown in <FIG>. While the valve body <NUM> is in the second position, the second monitoring surface <NUM> is not aligned with the sensor opening <NUM> and the first window <NUM> is in fluid communication with the bypass port <NUM>.

Referring to <FIG>, the valve body <NUM> defines the first recessed region <NUM>, the second recessed region <NUM>, and a third recessed region <NUM>. The third recessed region <NUM> is axially spaced apart from the first recessed region <NUM> and the second recessed region <NUM> relative to the first axis <NUM>. The third recessed region <NUM> radially extends from the outer surface <NUM> towards the first axis <NUM> and/or the first bore <NUM>.

The third recessed region <NUM> includes a fifth face <NUM>, a sixth face <NUM> that is spaced apart from the fifth face <NUM>, and a third monitoring surface <NUM> that extends between the fifth face <NUM> and the sixth face <NUM>. The fifth face <NUM> and the sixth face <NUM> may be disposed generally parallel to each other or may be disposed in a non-parallel, non-perpendicular relationship with respect to each other and the third monitoring surface <NUM>. The third monitoring surface <NUM> is disposed generally parallel to the first axis <NUM>, the first monitoring surface <NUM>, and the second monitoring surface <NUM>.

The first window <NUM> may be defined by or extend through at least one of the first monitoring surface <NUM>, the second monitoring surface <NUM>, and/or the third monitoring surface <NUM>.

A third radial distance, d3, is defined between the third monitoring surface <NUM> and the outer surface <NUM> of the valve body <NUM>. The third radial distance corresponds to a depth of the third recessed region <NUM>. The first radial distance is greater than the second radial distance and the third radial distance. In at least one embodiment, the second radial distance is greater than the third radial distance.

The valve body <NUM> may be in a first position that corresponds to a no fuel or low fuel condition in which fuel bypass flow from the first window <NUM> to the bypass port <NUM> is inhibited, as shown in <FIG>. While the valve body <NUM> is in the first position, the first window <NUM> is not in fluid communication with the bypass port <NUM> because the outer surface <NUM> of the valve body <NUM> blocks the bypass port <NUM>. The valve body <NUM> may be in a second position that corresponds to a medium fuel or non-maximum, non-minimum fuel condition facilitating a partial fuel bypass flow from the first window <NUM> to the bypass port <NUM>, as shown in <FIG>. While the valve body <NUM> is in the second position, the sensor opening <NUM> is generally aligned with the second monitoring surface <NUM> and the first window <NUM> is in partial fluid communication with the bypass port <NUM> because the outer surface <NUM> of the valve body <NUM> only partially blocks the bypass port <NUM>. The valve body <NUM> may be in a third position that corresponds to a maximum fuel condition facilitating a fuel bypass flow from the first window <NUM> to the bypass port <NUM>, as shown in <FIG>. While the valve body <NUM> is in the third position, the sensor opening <NUM> is generally aligned with the third monitoring surface <NUM> and the first window <NUM> is in fluid communication with bypass port <NUM> and the outer surface <NUM> of the valve body <NUM> is spaced apart from the bypass port <NUM>.

Referring to the Figures, the sensor <NUM> extends at least partially through the sensor opening <NUM> along the second axis <NUM>. The sensor <NUM> extends partially through the valve housing <NUM> and may towards the first window <NUM>, the first monitoring surface <NUM>, the second monitoring surface <NUM>, and/or the third monitoring surface <NUM>.

The sensor <NUM> may be at least one of a proximity probe and a magnetic coil, that is arranged to provide a signal indicative of a position of at least one of the first window <NUM>, the first monitoring surface <NUM>, the second monitoring surface <NUM>, and the third monitoring surface <NUM> relative to the sensor <NUM> to the controller <NUM>. The sensor <NUM> may also be arranged to provide a signal indicative of the depth of the first recessed region <NUM>, the second recessed region <NUM>, and the third recessed region <NUM> to the controller <NUM>. The position of at least one of the first monitoring surface <NUM>, the second monitoring surface <NUM>, and the third monitoring surface <NUM> relative to the sensor <NUM> or the depth of the first recessed region <NUM>, the second recessed region <NUM>, and the third recessed region <NUM> enables the sensor <NUM> to detect a position of the valve body <NUM> and therefore quantify the amount of bypass flow through the bypass port <NUM> based on the amount of the exposed monitoring surface within the sensor's field of view or the proximity of the monitoring surface <NUM>, <NUM>, <NUM> to the sensor <NUM>.

The controller <NUM> is arranged to receive the signal from the sensor <NUM>. The controller <NUM> is programmed to output for display a state of the metering valve <NUM> (e.g. the amount bypass flow through the bypass port <NUM>) based on the signal.

The sensor <NUM> in combination with the monitoring surfaces of the recessed regions <NUM>, <NUM>, <NUM> enables the fuel control system to quantify fuel pump performance or pump issues prior to failure by monitoring the amount of bypass flow through the valve body <NUM> through the bypass port <NUM>. The sensor <NUM> is a noncontacting sensor and can be tuned to individual applications and sizing without employing a flowmeter within the bypass port <NUM>. The amount of bypass flow through the bypass port <NUM> corresponds to an amount of fuel present within the fuel control system or the performance of the fuel pump of the fuel control system therefore the present disclosure enables the performance of the fuel pump to be more readily assessed based on the position of the valve body <NUM>.

Claim 1:
A metering valve for a fuel metering unit, comprising:
a valve housing (<NUM>) defining a housing bore (<NUM>) that extends from a first valve housing end towards a second valve housing end along a first axis; and
a valve body (<NUM>) disposed within the housing bore, the valve body having an outer surface that extends between a first valve body end (<NUM>) and a second valve body end (<NUM>) along the first axis (<NUM>), the valve body defining a first recessed region that radially extends from the outer surface towards the first axis; and characterized by:
a sensor (<NUM>) that extends at least partially through the valve housing along a second axis; and
a controller (<NUM>) arranged to receive a signal from the sensor, the controller programmed to output for display a state of the metering valve based on the signal.