Method for controlling timing of spark ignition for an internal combustion engine

Claim 1

A method for controlling the timing of spark ignition for an internal combustion engine having an output shaft rotated by a piston, the method comprising the steps of: establishing a timing characteristic of spark ignition relative to operating conditions of said engine so that a maximum output torque is produced by said output shaft in each of said operating conditions; monitoring the magnitude of load of said engine; comparing the magnitude of load monitored by said load monitoring step with a predetermined magnitude; detecting a first and second rotational positions of said engine before the arrival and at the arrival of said piston to the top dead center position thereof, respectively; monitoring the magnitude of vibration of said engine by a vibration responsive means coupled to said engine; averaging the magnitude of vibration monitored by said monitoring step during the rotation of said output shaft from said first to second rotational positions detected by said position detecting step; comparing the magnitude of vibration monitored by said vibration monitoring step with a reference magnitude proportional to the output average value of said averaging step; and changing the control mode of the timing of spark ignition in response to the load comparison result of said load comparing step such that the timing of spark ignition is controlled in accordance with said established timing characteristic of said establishing step and irrespective of the vibration comparison result of said vibration comparing step in response to the load comparison result indicative of the magnitude of load being smaller than said predetermined magnitude and that the timing of spark ignition is controlled in accordance with both said estblished timing characteristic of said establishing step and the vibration comparison result of said vibration comparing step in response to the load comparison result indicative of the magnitude of load being larger than said predetermined manitude.

Claim 2

A method for controlling the timing of spark ignition for an internal combustion engine having an output shaft rotated by a piston, the method comprising the steps of: establishing a timing characteristic of spark ignition relative to operating conditions of said engine so that a maximum output torque is produced by said output shaft in each of said operating conditions; monitoring the magnitude of load of said engine; comparing the magnitude of load monitored by said load monitoring step with a predetermined magnitude; detecting a first and second rotational positions of said engine before the arrival and at the arrival of said piston to the top dead center position thereof, respectively; monitoring the magnitude of vibration of said engine by a vibration responsive means coupled to said engine; averaging the magnitude of vibration monitored by said monitoring step during the rotation of said output shaft from said first to second rotational positions detected by said position detecting step; comparing the magnitude of vibration monitored by said vibration monitoring step with a reference magnitude proportional to the output average value of said averaging step; and changing the control mode of the timing of spark ignition in response to the load comparison result of said load comparing step such that the timing of spark ignition is controlled in accordance with said established timing characteristic of said establishing step and irrespective of the vibration comparison result of said vibration comparing step in response to the load comparison result indicative of the magnitude of load being smaller than said predetermined magnitude and that the timing of spark ignition is controlled in accordance with both said estblished timing characteristic of said establishing step and the vibration comparison result of said vibration comparing step in response to the load comparison result indicative of the magnitude of load being larger than said predetermined manitude.

Claim 11

A method for controlling the timing of spark ignition for an internal combustion engine having an output shaft rotated by a piston, the method comprising the steps of: establishing a timing characteristic of spark ignition relative to operating conditions of said engine so that a maximum output torque is produced by said output shaft in each of said operating conditions; monitoring the magnitude of load of said engine; comparing the magnitude of load monitored by said load monitoring step with a predetermined magnitude to produce a first signal when said load magnitude is less than said predetermined magnitude and a second signal when said load magnitude is greater than said predetermined magnitude; detecting a first and second rotational positions of said engine before the arrival and at the arrival of said piston to the top dead center position thereof, respectively; monitoring the magnitude of vibration of said engine by a vibration responsive means coupled to said engine; averaging the magnitude of vibration monitored by said monitoring step during the rotation of said output shaft from said first to second rotational positions detected by said position detecting step, said averaging step including the steps of: rectifying the output signals of said vibration monitoring step to produce a rectified signal, integrating said rectified signal during the rotation of said output shaft from said first to second rotational positions, measuring the interval of time during the rotation of said output shaft from said first to second rotational positions, and dividing the integrated output by the time interval between said first and second positions to produce an average magnitude value of vibration per unit time; comparing the magnitude of vibration monitored by said vibration monitoring step with a reference magnitude proportional to the output average value of said averaging step; and controlling the timing of spark ignition in accordance with said establishing step and irrespective of said vibration comparing step in response to said first signal and controlling the timing of spark ignition in accordance with both said establishing step and said vibration comparing step in response to said second signal.

Claim 12

A method for controlling the timing of spark ignition for an internal combustion engine having an output shaft rotated by a piston, the method comprising the steps of: establishing a timing characteristic of spark ignition relative to operating conditions of said engine so that a maximum output torque is produced by said output shaft in each of said operating conditions; monitoring the magnitude of load of said engine; comparing the magnitude of load monitored by said load monitoring step with a predetermined magnitude to produce a first signal when said load magnitude is less than said predetermined magnitude and a second signal when said load magnitude is greater than said predetermined magnitude; detecting a first and second rotational positions of said engine before the arrival and at the arrival of said piston to the top dead center position thereof, respectively; monitoring the magnitude of vibration of said engine by a vibration responsive means coupled to said engine; averaging the magnitude of vibration monitored by said monitoring step during the rotation of said output shaft from said first to second rotational positions detected by said position detecting step, said averaging step including the steps of: rectifying the output signals of said vibration monitoring step to produce a rectified signal, integrating said rectified signal during the rotation of said output shaft from said first to second rotational positions, measuring the interval of time during the rotation of said output shaft from said first to second rotational positions, and dividing the integrated output by the time interval between said first and second positions to produce an average magnitude value of vibration per unit time; comparing the magnitude of vibration monitored by said vibration monitoring step with a reference magnitude proportional to the output average value of said averaging step; and controlling the timing of spark ignition in accordance with said establishing step and irrespective of said vibration comparing step in response to said first signal and controlling the timing of spark ignition in accordance with both said establishing step and said vibration comparing step in response to said second signal.