Method and system for operating an engine at maximum torque with variable amount of dither

Claim 1

A method of operating an internal combustion engine at optimum output torque under varying operating conditions, said engine having an adjustable engine ignition timing variable, the setting of which controls the output torque, the method comprising: (a) oscillating the setting of the ignition timing variable on opposite sides of a variable reference setting; (b) sensing an output variable of said engine during at least three successive phases of the oscillation; (c) detecting whether the sensed output variable establishes one of first and second sequential relationships of a plurality of possible sequential relationships indicating that said variable reference setting is on one of first and second sides, respectively, of an optimum position; (d) adjusting said variable reference setting toward said optimum position in resonse to one of said detected first and second sequential relationships; (e) detecting an engine operating parameter; (f) varying at least one of the magnitude of the oscillation, the number of ignitions over which each of said phases occurs and the amount of said adjusting in said step (d) as a function of said detected engine operating parameter; and (g) repeating said steps (a) through (f).

Claim 2

A method of operating an internal combustion engine at optimum output torque under varying operating conditions, said engine having an adjustable engine ignition timing variable, the setting of which controls the output torque, the method comprising: (a) oscillating the setting of the ignition timing variable on opposite sides of a variable reference setting; (b) sensing an output variable of said engine during at least three successive phases of the oscillation; (c) detecting whether the sensed output variable establishes one of first and second sequential relationships of a plurality of possible sequential relationships indicating that said variable reference setting is on one of first and second sides, respectively, of an optimum position; (d) adjusting said variable reference setting toward said optimum position in resonse to one of said detected first and second sequential relationships; (e) detecting an engine operating parameter; (f) varying at least one of the magnitude of the oscillation, the number of ignitions over which each of said phases occurs and the amount of said adjusting in said step (d) as a function of said detected engine operating parameter; and (g) repeating said steps (a) through (f).

Claim 8

A method of operating an internal combustion engine at optimum output torque under varying operating conditions, said engine having an adjustable spark ignition variable, the setting of which controls the output torque, said method comprising: (a) constantly sensing an engine operating variable; (b) generating a reference ignition timing value as a function of said sensed engine operating variable; (c) generating a dither ignition timing value which varies on opposite sides of zero as a function of said sensed engine operating variable; (d) summing said reference and dither ignition timing value; (e) causing ignition to occur repeatedly, at a timing related to said summed ignition timing values so that ignition timing is oscillated on opposite sides of said reference timing by an amount proportional to said dither ignition timing value; (f) sensing the instantaneous speed value of said engine during at least three successive periods of the oscillation of said ignition timing; (g) comparing the sensed engine speed values against each other and detecting whether they establish one of first and second predetermined relationships of a plurality of possible sequential relationships indicating that said reference ignition timing value is greater or smaller than an optimum value; and (h) modifying said reference ignition timing value toward said optimum value in response to one of said first and second sequential relationships by an amount which is a function of said engine operating variable.

Claim 9

A method of operating an internal combustion engine at optimum output torque under varying operating conditions, said engine having an adjustable spark ignition variable, the setting of which controls the output torque, said method comprising: (a) constantly sensing an engine operating variable; (b) generating a reference ignition timing value as a function of said sensed engine operating variable; (c) generating a dither ignition timing value which varies on opposite sides of zero as a function of said sensed engine operating variable; (d) summing said reference and dither ignition timing value; (e) causing ignition to occur repeatedly, at a timing related to said summed ignition timing values so that ignition timing is oscillated on opposite sides of said reference timing by an amount proportional to said dither ignition timing value; (f) sensing the instantaneous speed value of said engine during at least three successive periods of the oscillation of said ignition timing; (g) comparing the sensed engine speed values against each other and detecting whether they establish one of first and second predetermined relationships of a plurality of possible sequential relationships indicating that said reference ignition timing value is greater or smaller than an optimum value; and (h) modifying said reference ignition timing value toward said optimum value in response to one of said first and second sequential relationships by an amount which is a function of said engine operating variable.