Automatic throttle calibration in a marine vessel

1. A method of calibrating an idle position of a throttle actuator in an electronic shift and throttle system, the method comprising the steps of:

commanding the throttle actuator to move a throttle towards a hard stop in increments;

measuring a voltage level of an electrical signal sent by a throttle position sensor at each said increment;

recording the voltage level of the electrical signal sent by the throttle position sensor at each said increment;

sensing a position of an actuator arm of the throttle actuator at each said increment; and

establishing the idle position as being the position of the actuator arm where the lowest voltage level was measured before the hard stop.

2. The method as claimed in claim 1 wherein the step of establishing the idle position includes establishing the idle position as being where the lowest voltage level was measured when the throttle is at least 0.75° away from the hard stop.

3. The method as claimed in claim 1 further including the step of opening the throttle before moving the throttle towards the hard stop in increments.

4. The method as claimed in claim 1 wherein the step of sensing the position of the actuator arm includes sensing a rotating position of an output shaft which drives the actuator arm.

5. The method as claimed in claim 1 further including the step of storing the idle position in EEPROM.

6. The method as claimed in claim 1 further including the steps of:

determining whether the throttle is at least 0.75° away from the hard stop in the idle position; and

storing the idle position in EEPROM if the throttle is at least 0.75° away from the hard stop in the idle position.

7. The method as claimed in claim 1 further including the steps of:

determining whether the voltage level of the electrical signal sent by the throttle position sensor has changed more than 0.2V while calibrating the idle position of the throttle actuator; and

storing the idle position in EEPROM if the voltage level of the electrical signal sent by the throttle position sensor has changed more than 0.2V while calibrating the idle position of the throttle actuator.

8. The method as claimed in claim 1 further including the steps of:

determining whether 0.3V is less than or equal to the voltage level of the electrical signal sent by the throttle position sensor when the throttle actuator is in the idle position; and

storing the idle position in EEPROM if 0.3V is less than or equal to the voltage level of the electrical signal sent by the throttle position sensor when the throttle actuator is in the idle position.

9. The method as claimed in claim 1 further including the steps of:

determining whether the voltage level of the electrical signal sent by the throttle position sensor is less than or equal to 0.62V when the throttle actuator is in the idle position; and

storing the idle position in EEPROM if the voltage level of the electrical signal sent by the throttle position sensor is less than or equal to 0.62V when the throttle actuator is in the idle position.

10. The method as claimed in claim 1 wherein the step of commanding the throttle to move towards the hard stop includes commanding the throttle to move towards the hard stop in increments of 1° towards the hard stop.

11. A method of calibrating an idle position of a throttle actuator in an electronic shift and throttle system, the method comprising the steps of:

commanding the throttle actuator to move the throttle towards a hard stop in increments of 1° towards the hard stop;

measuring a voltage level of an electrical signal sent by a throttle position sensor at each said increment;

recording the voltage level of the electrical signal sent by the throttle position sensor at each increment;

sensing a rotating position of an output shaft of the throttle actuator at each said increment; and

establishing the idle position as being the rotating position of the output shaft where the lowest voltage level was measured when the throttle is at least 0.75° away from the hard stop.

12. The method as claimed in claim 11 further including the step of determining whether the following parameters have been met:

(a) the voltage level of the electrical signal sent by the throttle position sensor has changed more than 0.2V while calibrating the idle position of the throttle actuator;

(b) the voltage level of the electrical signal sent by the throttle position is greater than 0.3V when the throttle actuator is in the idle position; and

(c) the voltage level of the electrical signal sent by the throttle position sensor is less than or equal to 0.62V when the throttle actuator is in the idle position.

13. The method as claimed in claim 11 further including the step of storing the idle position in EEPROM if all the parameters of claim 12 are met.

14. The method as claimed in claim 11 further including the step of recalibrating the idle position of the throttle actuator if all the parameters of claim 12 are not met.

15. An electronic shift and throttle system comprising:

a throttle actuator including a motor for rotating an output shaft, the output shaft transferring motion to an actuator arm;

an actuator position sensor for sensing a rotating position of the output shaft;

a linkage connecting the actuator arm to a throttle, the throttle being moveable between a hard stop and an open throttle position;

a controller for commanding the throttle actuator to move the throttle towards the hard stop in increments;

a position sensor for sensing a position of the throttle at each said increment;

a memory for recording a voltage level of an electrical signal sent by the throttle position sensor at each said increment; and

a microprocessor for correlating the rotating position of the output shaft with the position of the throttle based on the voltage level of the electrical signal, a duty cycle of the actuator position sensor and an amount of current flowing into the motor, wherein the microprocessor establishes as idle position as being the position of the actuator arm where the lowest voltage was measured before the hard stop.

16. An electronic shift and throttle system as claimed in claim 15 wherein the actuator sensor senses the position of a magnet disposed on the output shaft.

17. An electronic shift and throttle system as claimed in claim 15 wherein the controller is an electronic servo module.