Position sensing for mechanical fuel injection systems

A fuel system for an aviation engine, comprising:

• a mechanical fuel servo that includes:
• a servo body that defines an air conduit and a fuel path, and
• at least one of:
• (i) a throttle valve assembly coupled to the servo body, the throttle valve assembly including a throttle shaft constructed and arranged to rotate responsive to a first control input to control airflow through the air conduit, and a throttle position sensor constructed and arranged to provide a first set of sensor signals that indicates an angular position of the throttle shaft, or
• (ii) a fuel delivery assembly coupled to the servo body, the fuel delivery assembly including a mixture valve shaft constructed and arranged to rotate responsive to a second control input to control fuel flow through the fuel path, and a mixture valve position sensor constructed and arranged to provide a second set of sensor signals that indicates an angular position of the mixture valve shaft;
• a set of discharge nozzles constructed and arranged to receive fuel from the mechanical fuel servo and provide fuel to a set of internal combustion chambers of the aviation engine;
• and
• an electronic controller constructed and arranged to:
• receive a set of sensor signals as feedback from at least one of the throttle position sensor or the mixture valve position sensor, and
• direct rotation of at least one of the throttle shaft or the mixture valve shaft based on the feedback to provide closed-loop control of fuel flow from the mechanical fuel servo to the set of discharge nozzles.

A method of controlling fuel flow to an aviation engine, comprising:

• electronically rotating a throttle shaft and a mixture valve shaft of a mechanical fuel servo, the throttle shaft constructed and arranged to control airflow through an air conduit defined by a servo body of the mechanical fuel servo, the mixture valve shaft constructed and arranged to control fuel flow through a fuel path defined by the servo body;
• in response to electronically rotating the throttle shaft and the mixture valve shaft, providing a first set of sensor signals and a second set of sensor signals to an electronic controller, the first set of sensor signals indicating an angular position of the throttle shaft, the second set of sensor signals indicating an angular position of the mixture valve shaft;
• and
• after providing the first set of sensor signals and the second set of sensor signals, further electronically rotating the mixture valve shaft based on instructions from the electronic controller providing closed-loop control of the mechanical fuel servo, the closed-loop control being based on the first set of sensor signals and the second set of sensor signals provided to the electronic controller.