Engine cycle timing and synchronization based on crankshaft angle measurements

An engine cycle timing and synchronizing system for an engine having a plurality of cylinders which are each ignited in predetermined order during two rotations of a crankshaft, and at least two pistons of which reciprocate at a common phase, the system comprising:

• signal generating means for generating pulse signals at constant rotational intervals of the crankshaft and for generating a reference signal at a predetermined crank angle of said crankshaft;
• detecting means for detecting a reference position of said crankshaft based on said reference signal;
• forcible stop means for causing said crankshaft to forcibly stop at a position which does not reversely rotate when the engine stops;
• storing means for storing the number of pulse signals occurring after said reference position of said crankshaft corresponding to a specific cylinder condition which appears once during two rotations of said crankshaft;
• and
• means for identifying a cylinder responsive to the number of pulse signals after passage of said reference position of said crankshaft corresponding to said specific cylinder.

An engine cycle timing and synchronizing system for an engine having a plurality of cylinders which are each ignited in predetermined order during two rotations of a crankshaft, and at least two pistons of which reciprocate at a common phase, the system comprising:

• signal generating means for generating pulse signals at constant rotational intervals of a crankshaft and for generating a reference signal at a predetermined crank angle of said crankshaft;
• detecting means for detecting a reference position of said crankshaft based on said reference signal;
• setting means for setting a provisional reference position of said crankshaft corresponding to a specific cylinder condition which appears once during each two rotations of said crankshaft;
• determination means for determining whether or not said provisional reference position of said crankshaft is correct depending on whether engine rotation increases when said engine is started using said provisional reference position of said crankshaft;
• correcting means for correcting said provisional reference position of said crankshaft so as to be shifted by one rotation of said crankshaft when the determination means determines that said provisional reference position of said crankshaft is not correct;
• and
• means for making a cylinder determination responsive to the number of pulse signals occurring after passage of said reference position of said crankshaft corresponding to said specific cylinder.

An engine cycle timing and synchronizing system for an engine having a plurality of cylinders which are each ignited in predetermined order during two rotations of a crankshaft, and at least two pistons of which reciprocate at a common phase, the system comprising:

• signal generating means for generating pulse signals at constant rotational intervals responsive to rotations of a crankshaft and for generating a reference signal at a predetermined crank angle of said crankshaft;
• detecting means for detecting a reference position of said crankshaft based on said reference signal;
• setting means for setting a provisional reference position of said crankshaft corresponding to a specific cylinder condition which appears once during each two rotations of said crankshaft;
• idle stabilizing means for controlling ignition timings for said cylinders so that an idling rotation speed is stabilized when said engine is driven at an idling state based on said provisional reference position of said crankshaft;
• determination means for determining whether or not said provisional reference position of said crankshaft is correct depending on the degree of fluctuation of engine rotational speed when said idle stabilizing means controls said ignition timings based on said provisional reference position of said crankshaft;
• correcting means for correcting said provisional reference position of said crankshaft so as to be shifted by one rotation of said crankshaft when determination means determines that said provisional reference position of said crankshaft is not correct;
• and
• means for making a cylinder determination responsive to the number of pulse signals occurring after passage of said reference position of said crankshaft corresponding to said specific cylinder.

An engine cycle timing and syunchronizing system for an engine having a plurality of cylinders which are each ignited in predetermined order during two rotations of a crankshaft and at least two pistons of which reciprocate at a common phase, the system comprising:

• signal generating means for generating pulse signals at constant rotational intervals responsive to rotations of the crankshaft and for generating a reference signal at a predetermined crank angle of said crankshaft;
• detecting means for detecting a reference position of said crankshaft based on said reference signal;
• setting means for setting a provisional reference position of said crankshaft corresponding to a specific cylinder condition which appears once during each two rotations of said crankshaft;
• idle stabilizing means for controlling amounts of fuel injection for said cylinders so that an idling rotation speed is stabilized when said engine is driven at an idling state based on said provisional reference position of said crankshaft;
• determination means for determining whether or not said provisional reference position of said crankshaft is correct depending on the amount of fluctuation in engine rotational speed when said idle stabilizing means controls said amounts of fuel injection based on said provisional reference position of said crankshaft;
• correcting means for correcting said provisional reference position of said crankshaft so as to be shifted by one rotation of said crankshaft when the determination means determines that said provisional reference position of said crankshaft is not correct;
• and
• means for making a cylinder determination responsive to the number of pulse signals occurring after passage of said reference position of said crankshaft corresponding to said specific cylinder.

An engine cycle timing and synchronizing apparatus for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said apparatus comprising:

• a wheel having angularly spaced detectable structures therearound, said wheel being attached to rotate with a crankshaft and having a reference portion that is of uniquely different structure than the remainder of the wheel;
• an electrical signal transducer mounted adjacent the path of said wheel as it rotates and disposed to produce electrical signals representing the passage thereby of said wheel structures;
• a synchronizing signal memory storing an indication of the relative phase of said crankshaft rotation to an engine combustion cycle;
• an electrical signal counter and memory connected to count and store the number of said electrical signals occurring after passage of said reference portion just prior to engine stoppage and the number of said electrical signals occurring before the next passage of said reference portion just after engine restart;
• and
• an electrical signal processor connected to update said synchronizing signal memory upon engine restart based on the content of said electrical signal counter and memory.

An engine cycle timing and synchronizing method for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said method comprising:

• rotating a wheel having angularly spaced detectable structures therearound together with a crankshaft, said wheel having a reference portion that is of uniquely different structure than the remainder of the wheel;
• transducing an electrical signal from said wheel as it rotates to produce electrical signals representing the passage thereby of said wheel structures;
• storing an indication of the relative phase of said crankshaft rotation to an engine combustion cycle;
• counting and storing the number of said electrical signals occurring after passage of said reference portion just prior to engine stoppage and the number of said electrical signals occurring before the next passage of said reference portion just after engine restart;
• and
• updating said stored indication of relative phase upon engine restart based on the counted and stored number of said electrical signals.

An engine cycle timing and synchronizing method for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said method comprising the steps of:

• generating first signals representing rotational movements of a crankshaft past a sensor;
• generating a reference signals representing passage of a predetermined reference portion of said crankshaft with respect to said sensor;
• determining whether said reference crankshaft portion has undergone reverse motion past said sensor upon engine stoppage;
• and
• adjusting engine cycle timing with respect to a camshaft by substantially 360.degree. of crankshaft rotation, if needed, upon engine restart in response to said determining step to maintain synchronization with the camshaft.

An engine cycle timing and synchronizing method for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said method comprising:

• generating first signals representing rotational movements of a crankshaft past a sensor;
• generating a reference signals representing passage of a predetermined reference portion of said crankshaft with respect to said sensor;
• forcibly stopping said engine upon engine turn-off at a point in the combustion cycle that substantially prevents reverse rotation of said reference crankshaft portion past said sensor upon engine stoppage;
• storing the number of said first signals occurring prior to engine stoppage and after the last reference signal prior to engine stoppage, and
• using said stored number of first signals upon engine re-start to maintain synchronization between a camshaft and engine cycle timing as otherwise determined by said first and reference signals.

An engine cycle timing and synchronizing apparatus for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said apparatus comprising the steps of:

• means for generating first signals representing rotational movements of a crankshaft past a sensor;
• means for generating a reference signals representing passage of a predetermined reference portion of said crankshaft with respect to said sensor;
• means for determining whether said reference crankshaft portion has undergone reverse motion past said sensor upon engine stoppage;
• and
• means for adjusting engine cycle timing with respect to a camshaft by substantially 360.degree. of crankshaft rotation, if needed, upon engine restart in response to said means for determining to maintain synchronization with the camshaft.

An engine cycle timing and synchronizing apparatus for use with a multi-cylinder four-cycle reciprocating piston engine having an engine combustion cycle that occurs during two complete revolutions, of a crankshaft while a mechanically coupled valve-operating camshaft undergoes a single revolution, said apparatus comprising:

• means for generating first signals representing rotational movements of a crankshaft past a sensor;
• means for generating a reference signals representing passage of a predetermined reference portion of said crankshaft with respect to said sensor;
• means for forcibly stopping said engine upon engine turn-off at a point in the combustion cycle that substantially prevents reverse rotation of said reference crankshaft portion past said sensor upon engine stoppage;
• means for storing the number of said first signals occurring prior to engine stoppage and after the last reference signal prior to engine stoppage, and
• means for using said stored number of first signals upon engine re-start to maintain synchronization between a camshaft and engine cycle timing as otherwise determined by said first and reference signals.