Water/fuel ratio control using complementary filtering between valve and flowmeter feedback signals

A water-fuel control system for an engine comprising:

• a controller, the controller implementing a complementary filter, configured to:
• receive a first signal and a second signal, wherein a response bandwidth frequency of the first signal is less than the response bandwidth frequency of the second signal;
• calculate an error signal using the first signal and the second signal;
• lag the error signal to create a lagged error signal;
• add the lagged error signal and the second signal to create a compensated signal;
• receive a switch control signal, the compensated signal, and the second signal;
• determine the controller implementing a switch logic, whether to send at least one of the compensated signal or the second signal;
• calculate a water flow request, wherein the calculating is performed using a desired water-fuel ratio and the at least one of the compensated signal or the second signal;
• and
• send the water flow request to a water control system, wherein the water flow request is used to at least one of open or close a water valve.