Method and apparatus to determine the timing of cyclically repetitive events, particularly ignition instant for internal combustion engines
First Claim
1. Method to determine the timing of the ignition instant with respect to cyclical operation of a movable part of an internal combustion engine, in dependence on engine speed, comprising the steps ofgenerating a sequence of pulses as a function of movement of, and synchronously with operation of the engine part;
- generating a first reference pulse upon occurrence of a predetermined position of the engine part;
determining a timing interval having a predetermined timing duration upon generation of the first reference pulse;
generating a second reference pulse occurring after said first reference pulse, and after said timing interval;
counting the pulses of the pulse sequence after termination of the timing pulse and until occurrence of said second reference pulse, and accumulating said count in a counter (16);
decrementing the count in the counter until the count state of the counter (16) has reached a predetermined level;
and generating an output signal when the count state of said counter has reached said predetermined level.
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Abstract
A first sequence of pulses is generated synchronously with operation of the apparatus, for example with rotation of the engine crankshaft. A reference pulse is generated upon occurrence of an operating state, for example a predetermined angular position of the crankshaft, as well as a second reference pulse occurring after the first and after a predetermined time interval has elapsed. The pulses of the sequence are counted and accumulated until the second reference pulse occurs, and are then decremented at the same pulse rate until the counter reaches a predetermined count state (for example zero), at which moment the event is triggered, for example an ignition pulse issued. The system permits adaptation to various reference pulse generators by adjustment of timing intervals, thus permitting use of reference pulses of less accuracy with respect to the apparatus with which the pulse generators are associated.
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Citations
18 Claims
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1. Method to determine the timing of the ignition instant with respect to cyclical operation of a movable part of an internal combustion engine, in dependence on engine speed, comprising the steps of
generating a sequence of pulses as a function of movement of, and synchronously with operation of the engine part; -
generating a first reference pulse upon occurrence of a predetermined position of the engine part; determining a timing interval having a predetermined timing duration upon generation of the first reference pulse; generating a second reference pulse occurring after said first reference pulse, and after said timing interval; counting the pulses of the pulse sequence after termination of the timing pulse and until occurrence of said second reference pulse, and accumulating said count in a counter (16); decrementing the count in the counter until the count state of the counter (16) has reached a predetermined level; and generating an output signal when the count state of said counter has reached said predetermined level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. System to determine the timing of the ignition instant with respect to cyclical operation of a movable internal combustion engine part, in dependence on engine speed comprising
angle pulse generating means (10, 11, 12) providing a sequence of pulses as a function of movement of, and synchronously with operation of the engine part; -
reference pulse generating means (10, 13,
14) providing first and second reference pulses upon occurrence of predetermined positions of movable elements of the engine part,a main counter (16) having up-count (17) and down-count (18) inputs; a timing circuit (39) providing a timing interval; logic gates (32,
26) connected to the up-count and down-count inputs (17,
18) of the main counter (16), respectively, the logic gates logically applying angle pulses from the angle pulse generating means (10, 11,
12) to the up-count and down-count inputs (17,
18) of the main counter (16) upon generation of a first reference pulse, but after the timing interval of said timing circuit (39) to the up-count terminal, and after generation of the second reference pulse to the down-count terminal;and decoding means (20) connected to the main counter (16) and providing an output signal when the main counter has decremented to a predetermined count state. - View Dependent Claims (12, 13, 14)
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15. Ignition timing system for internal combustion engines, comprising
rotating means (10) and transducer means (11, 12) providing a sequence of angle pulses (1.1) synchronously with and as a function of rotation of the engine, and reference transducer means (13, 14) providing two reference marker pulses (1.2) at predetermined angular positions of the crankshaft of the engine; -
a reversible main counter (16) and decoding means (20) connected to the counter and providing an output signal when the count state of the counter reaches a predetermined value; up-count logic gate means (32) connected to the up-count input (17) of the reversible main counter (16) and down-count logic gate means (26) connected to the down-count input (18) of the reversible main counter (16); the timing circuit (39) being connected to and controlled by the first reference pulse of the reference pulse transducer means to initiate a timing signal and, after elapse thereof, controlling the up-count gate (32) to pass the angle pulses from the angle transducer means (11,
12) to the main counter (16) to count up after said timing interval has elapsed, and until the second reference pulse occurs, the up-count logic gate being connected to and controlled by the second reference pulse;the down-count logic gate (26) connected to the down-count input (18) of the reversible main counter (16) controlling application of the angle transducer pulses from the angle transducer means (11,
12) to the down-count input after the second reference pulse, the decoding circuit (20) sensing when the counter has decremented to the predetermined value and providing an ignition trigger output signal. - View Dependent Claims (16, 17, 18)
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Specification