Method of and device for automatically adjusting the ignition timing of a controlled ignition engine

Claim 1

A method of adjusting the ignition timing of a controlled ignition engine comprising at least two cylinders having knock detecting means associated therewith, and means for adjusting, according to the spark timing in each cylinder, the angular position of the crankshaft to correspond to the time the flame front reaches in each cylinder a fixed reference position, the method comprising: (a) adjusting the ignition timing when knocking occurs in at least the one cylinder wherein said knocking is detected, to eliminate said knocking; (b) in the absence of knocking, and separately for each cylinder, detecting the passage of the flame front through said reference position, and when said detection is performed a predetermined number of times P for a number of cycles of operation of the engine at most equal to a predetermined number Q, generating an average value of the values of the angular position of the crankshaft corresponding to the times when said flame front is detected, and producing a new value for the ignition timing based on said average value of the angular position with respect to which said average value is a predetermined value, the new value for the ignition timing for said one cylinder being-used for controlling the ignition timing of the other cylinder if the number of times the flame front is detected in the other cylinder is less than the value P for said number of cycles Q; and (c) in the absence of knocking and when the detecting of the number of flame fronts in each cylinder, being not less than P for the number of cycles Q, adjusting the ignition timing in each cylinder by a predetermined amount which is a function of at least one parameter characteristic of the operation of the engine.

Claim 2

A method of adjusting the ignition timing of a controlled ignition engine comprising at least two cylinders having knock detecting means associated therewith, and means for adjusting, according to the spark timing in each cylinder, the angular position of the crankshaft to correspond to the time the flame front reaches in each cylinder a fixed reference position, the method comprising: (a) adjusting the ignition timing when knocking occurs in at least the one cylinder wherein said knocking is detected, to eliminate said knocking; (b) in the absence of knocking, and separately for each cylinder, detecting the passage of the flame front through said reference position, and when said detection is performed a predetermined number of times P for a number of cycles of operation of the engine at most equal to a predetermined number Q, generating an average value of the values of the angular position of the crankshaft corresponding to the times when said flame front is detected, and producing a new value for the ignition timing based on said average value of the angular position with respect to which said average value is a predetermined value, the new value for the ignition timing for said one cylinder being-used for controlling the ignition timing of the other cylinder if the number of times the flame front is detected in the other cylinder is less than the value P for said number of cycles Q; and (c) in the absence of knocking and when the detecting of the number of flame fronts in each cylinder, being not less than P for the number of cycles Q, adjusting the ignition timing in each cylinder by a predetermined amount which is a function of at least one parameter characteristic of the operation of the engine.

Claim 6

A method of adjusting the ignition timing of a controlled ignition engine, comprising the steps of detecting in at least one cylinder the time of passage of the interface between the burnt gases and the fresh gases through a reference position in the combustion chamber during the combustion phase, and adjusting the ignition timing to cause said time of passage to coincide with the time of passage of the crankshaft through a predetermined angular position selected so as to obtain optimum operation of the engine, and wherein said reference position corresponds to the interface between burnt gases and the fresh gas wherein the ratio of the volume of burnt gases to the overall gas volume in the cylinder comprises 0.4 to 0.9.

Claim 7

A method of adjusting the ignition timing of a controlled ignition engine, comprising the steps of detecting in at least one cylinder the time of passage of the interface between the burnt gases and the fresh gases through a reference position in the combustion chamber during the combustion phase, and adjusting the ignition timing to cause said time of passage to coincide with the time of passage of the crankshaft through a predetermined angular position selected so as to obtain optimum operation of the engine, and wherein said reference position corresponds to the interface between burnt gases and the fresh gas wherein the ratio of the volume of burnt gases to the overall gas volume in the cylinder comprises 0.4 to 0.9.