Engine control unit systems and methods for a boat propulsion system

1. An engine control unit for a boat propulsion system comprising:

a predicted boat speed value generator adapted to provide predicted boat speed values by receiving and processing signals related to an engine speed, an intake pressure taken at a downstream side of a throttle valve, a lever position, a shift position, and a throttle position;

a control signal generator adapted to receive the predicted boat speed values from the predicted boat speed value generator to determine an injection amount, an amount of air, and an ignition timing based on the predicted boat speed values to provide a fuel injection control signal, an air adjustment control signal, and an ignition timing control signal, respectively;

wherein the predicted boat speed value generator is adapted to perform a predicted boat speed mapped value extraction process to search through a predicted boat speed value map during a constant speed operation and an acceleration, based on the engine speed and the intake pressure, to extract and provide a predicted boat speed mapped value; and

wherein the predicted boat speed value generator is further adapted to perform a predicted decelerating boat speed value output process to initially receive the last predicted boat speed mapped value at a time of deceleration, establish an initial predicted boat speed value by multiplying attenuation coefficients that vary according to the shift positions by the predicted boat speed mapped value obtained at an end of the deceleration, perform a similar computation in each following cycle using the last predicted boat speed mapped value, and provide an attenuated predicted boat speed value in every cycle.

2. The engine control unit for the boat propulsion system according to claim 1 , wherein the predicted decelerating boat speed value output process is adapted to set different attenuation validation times for each shift position of forward, neutral, and reverse.

3. The engine control unit for the boat propulsion system according to claim 2 , wherein the predicted boat speed value generator is further adapted to perform a predicted recovering boat speed value output process, to search through the predicted boat speed value map when a boat speed transitions from a deceleration to a constant speed or to an acceleration, based on the intake pressure and the engine speed at a beginning of the boat speed transition, to extract the predicted boat speed mapped value, and at approximately the same time, receive the predicted boat speed value obtained at the end of deceleration, to establish the initial predicted boat speed value by multiplying the incremental coefficient that varies according to the shift positions by the predicted boat speed mapped value obtained at the end of the deceleration, perform a similar computation in each following cycle by applying the last predicted boat speed mapped value and the predicted boat speed mapped value, and provide the predicted boat speed value, which is gradually increasing, in every cycle.

4. The engine control unit for the boat propulsion system according to claim 3 , wherein the predicted boat speed value generator is further adapted to perform a process to determine if a boat speed has transitioned to a deceleration state, or has transitioned from a boat speed recovery state to a constant speed or an acceleration state, and, based on the predicted recovering boat speed value output process, recover control based on the predicted boat speed mapped value extraction process.

5. The engine control unit for the boat propulsion system according to claim 1 , wherein the predicted boat speed value generator is further adapted to perform a predicted recovering boat speed value output process, to search through the predicted boat speed value map when a boat speed transitions from a deceleration to a constant speed or to an acceleration, based on the intake pressure and the engine speed at a beginning of a speed transition, to extract the predicted boat speed mapped value, and at approximately the same time, receive the predicted boat speed value obtained at the end of deceleration, to establish the initial predicted boat speed value by multiplying the incremental coefficient that varies according to the shift positions by the predicted boat speed mapped value obtained at the end of the deceleration, perform a similar computation in each following cycle by applying the last predicted boat speed mapped value and the predicted boat speed mapped value, and provide the predicted boat speed value, which is gradually increasing, in every cycle.

6. The engine control unit for the boat propulsion system according to claim 5 , wherein the predicted boat speed value generator is further adapted to perform a process to determine if a boat speed has transitioned to a deceleration state, or has transitioned from a boat speed recovery state to a constant speed or an acceleration state, and, based on the predicted recovering boat speed value output process, recover control based on the predicted boat speed mapped value extraction process.

7. A boat, comprising the engine control unit for the boat propulsion system according to claim 1 .

8. A boat, comprising the engine control unit for the boat propulsion system according to claim 2 .

9. A boat, comprising the engine control unit for the boat propulsion system according to claim 3 .

10. A boat, comprising the engine control unit for the boat propulsion system according to claim 4 .

11. A boat, comprising the engine control unit for the boat propulsion system according to claim 5 .

12. A boat, comprising the engine control unit for the boat propulsion system according to claim 6 .

13. A method for controlling a boat propulsion system, the method comprising:

receiving signals related to an engine speed, an intake pressure, a lever position, a shift position, and a throttle position;

processing the signals to provide predicted boat speed values;

determining an injection amount, an amount of air, and an ignition timing based on the predicted boat speed values;

providing a fuel injection control signal, an air adjustment control signal, and an ignition timing control signal based on the determining;

searching through a predicted boat speed value map during a constant speed operation and an acceleration, based on the signals related to the engine speed and the intake pressure;

providing a predicted boat speed mapped value based on the searching; and

determining an initial predicted boat speed value by multiplying attenuation coefficients that vary according to the shift positions by the predicted boat speed mapped value obtained at an end of a deceleration.

14. The method of claim 13 , further comprising repeating the determining of the initial predicted boat speed value using the last predicted boat speed mapped value to provide an attenuated predicted boat speed value in every cycle.

15. The method of claim 14 , further comprising setting different attenuation validation times based on the shift positions of forward, neutral, and reverse to be used by the determining of the initial predicted boat speed value.

16. The method of claim 15 , further comprising:

searching through the predicted boat speed value map when a boat speed transitions from a deceleration to a constant speed or to an acceleration, based on the signals related to the intake pressure and the engine speed at a beginning of the boat speed transition to provide the predicted boat speed mapped value;

receiving the predicted boat speed value obtained at the end of the deceleration;

establishing the initial predicted boat speed value by multiplying an incremental coefficient that varies according to the shift positions by the predicted boat speed mapped value obtained at the end of the deceleration; and

performing the establishing in each following cycle by applying the last predicted boat speed mapped value and the predicted boat speed mapped value to provide the predicted boat speed value, which is gradually increasing, in every cycle.

17. The method of claim 16 , further comprising:

determining if a boat speed has transitioned to a deceleration state or has transitioned from a boat speed recovery state to a constant speed or an acceleration state; and

recovering control based on the searching and the providing of the predicted boat speed mapped value and based on the performing of the establishing.