JP5674500B2 - Pulse signal detection method, pulse signal detection circuit, ignition device for internal combustion engine, and program - Google Patents

Description

  The present invention relates to a pulse signal detection method, a pulse signal detection circuit, an ignition device for an internal combustion engine, and a program.

  An ignition device (for example, CDI) for an internal combustion engine (engine) includes a rotor attached to a crankshaft of the internal combustion engine, two reluctors provided on the outer periphery of the rotor, a pickup coil, a pulse signal detection circuit, a pulse And an ignition unit that ignites the internal combustion engine in accordance with the ignition timing from the signal detection circuit.

  The pickup coil detects the front end portion and the rear end portion of each reluctator, and outputs an engine rotation pulse signal (crank angle signal) repeatedly having positive and negative detected pulses corresponding to the rotation of the crankshaft. The pulse signal detection circuit detects a detected pulse of the engine rotation pulse signal using a microcomputer. The microcomputer calculates a fixed ignition timing, a calculated ignition timing, and an engine speed based on the detected pulse to be detected. Specifically, the pulse signal detection circuit includes a positive pulse signal having a pulse corresponding only to a positive detected pulse of the engine rotation pulse signal, and a pulse corresponding only to a negative detected pulse of the engine rotation pulse signal. A negative pulse signal having

  The positive pulse signal is inputted to the interrupt terminal of the microcomputer, and the microcomputer performs time measurement based on the pulse of the positive pulse signal. The negative pulse signal is input to the input capture terminal of the microcomputer, and the microcomputer performs time measurement based on the negative pulse signal pulse.

  The microcomputer acquires a timer value from the free-run timer at a timing when a predetermined pulse of the positive pulse signal is detected, and calculates the engine speed and the calculated ignition timing based on the acquired timer value. Further, the microcomputer acquires a timer value from the free-run timer at a timing when a predetermined pulse of the negative pulse signal is detected, and calculates a fixed ignition timing based on the acquired timer value.

  When a negative pulse signal pulse is detected at the input capture terminal dedicated to time measurement, the microcomputer can acquire the timer value instantly. On the other hand, when a pulse of a positive pulse signal is detected at the general-purpose interrupt terminal, the microcomputer interrupts the process being executed and starts the interrupt process, and acquires a timer value using this interrupt process.

  A microcomputer having only one input capture terminal is less expensive than a microcomputer having a plurality of input capture terminals. Therefore, an ignition device provided with this microcomputer can also be made inexpensive.

  In connection with the above ignition device, for example, an ignition device described in Patent Document 1 is also known.

JP 2004-176625 A

  However, since the microcomputer included in the conventional pulse signal detection circuit described above acquires a timer value using interrupt processing when a pulse is input to the interrupt terminal, the timing at which the pulse is detected as shown in FIG. An error time due to the interrupt processing occurs between (time t10) and the timing (time t11) when the timer value is acquired. In other words, the microcomputer sets the timer value according to the execution time of the interrupt processing until the timer value is acquired, and in addition to this, the waiting time until the other interrupt processing ends when other interrupt processing is being executed. The acquisition timing is delayed from the timing (time t10) when the pulse is detected. Therefore, there is a problem that an error with respect to the target ignition timing occurs in the ignition timing calculated based on the acquired timer value.

  Therefore, the embodiment according to the present invention provides a pulse signal detection method, a pulse signal detection circuit, an ignition device, and a program that can obtain accurate timing even when an inexpensive microcomputer is used.

A pulse signal detection method according to an embodiment of one aspect of the present invention includes:
A pulse signal detection method in a pulse signal detection circuit comprising a detection unit, a processing unit, a timer, a target timer value calculation unit, a determination unit, and a signal output unit, to which a detected pulse signal is input,
A first step of detecting a first detected pulse of the detected pulse signal by the detection unit;
A second step of interrupting a process being executed and starting an interrupt process after the first detected pulse is detected by the processing unit;
A third step of acquiring a timer value from the timer as a first detection timer value by the processing unit using the interrupt processing;
The target timer value calculation unit adds a predetermined first output time to the acquired first detection timer value, and from the addition result, the timing at which the first detected pulse is detected and the first detection A fourth step of calculating a first target timer value obtained by subtracting a previously determined error time, which is a difference from the timing at which the timer value is acquired;
A fifth step of determining whether or not the timer value of the timer has reached the first target timer value by the determination unit;
And a sixth step of outputting a first output signal by the signal output unit when the timer value of the timer reaches the first target timer value.

In the pulse signal detection method,
The detected pulse signal is generated according to the rotation of the internal combustion engine,
The first output signal may be a signal for igniting the internal combustion engine.

In the pulse signal detection method,
The timer repeatedly counts from the initial timer value to the final timer value as the timer value,
The first output time may be longer than the error time.

In the pulse signal detection method,
Before the first step, the engine speed calculation unit further includes a seventh step of calculating the rotation speed of the internal combustion engine based on the detected pulse signal,
Between the third step and the fourth step, an output time setting unit may further include an eighth step of setting the first output time according to the rotation speed.

In the pulse signal detection method,
Between the third step and the eighth step, the processing unit further includes a ninth step of determining whether the rotational speed is equal to or higher than a predetermined rotational speed,
In the ninth step, when the rotational speed is equal to or higher than the predetermined rotational speed, the process may proceed to the eighth step.

In the pulse signal detection method,
When the rotation speed is lower than the predetermined rotation speed in the ninth step, the detection unit detects a second detected pulse different from the first detected pulse detected in the first step. A tenth step,
An eleventh step of interrupting a process being executed and starting an interrupt process after the second detected pulse is detected in the tenth step by the processing unit;
A twelfth step of acquiring the timer value as a second detection timer value from the timer by the processing unit using the interrupt process of the eleventh step;
The target timer value calculation unit calculates a second target timer value obtained by adding a second output time to the second detection timer value acquired in the twelfth step and subtracting the error time from the addition result. A thirteenth step,
A fourteenth step of determining whether or not the timer value of the timer has reached the second target timer value by the determination unit;
The signal output unit may further include a fifteenth step of outputting a second output signal for igniting the internal combustion engine when the timer value of the timer reaches the second target timer value.

  In the pulse signal detection method, the second output time may be constant regardless of the rotational speed.

A pulse signal detection circuit according to an embodiment of one aspect of the present invention includes:
A timer that measures time according to the timer value;
A detector for detecting a first detected pulse of the detected pulse signal;
After the first detected pulse is detected, a process being executed is interrupted to start an interrupt process, and the interrupt value is used to acquire the timer value from the timer as a first detection timer value And
A predetermined first output time is added to the acquired first detection timer value, and from the addition result, a timing at which the first detected pulse value is detected, a timing at which the first detection timer value is acquired, and A target timer value calculator that calculates a first target timer value obtained by subtracting a previously determined error time,
A determination unit for determining whether or not the timer value of the timer has reached the first target timer value;
And a signal output unit that outputs a first output signal when the timer value of the timer reaches the first target timer value.

In the pulse signal detection circuit,
The detected pulse signal is generated according to the rotation of the internal combustion engine,
The first output signal may be a signal for igniting the internal combustion engine.

In the pulse signal detection circuit,
The timer repeatedly counts from the initial timer value to the final timer value as the timer value,
The first output time may be longer than the error time.

In the pulse signal detection circuit,
A rotation speed calculation unit for calculating the rotation speed of the internal combustion engine based on the detected pulse signal;
An output time setting unit that sets the first output time according to the number of rotations may be further included.

In the pulse signal detection circuit,
The processing unit determines whether the rotational speed is equal to or higher than a predetermined rotational speed,
When the rotational speed is equal to or higher than the predetermined rotational speed,
The output time setting unit sets the first output time according to the rotation speed,
The target timer value calculation unit may calculate the first target timer value.

In the pulse signal detection circuit,
When the rotational speed is lower than the predetermined rotational speed,
The detecting unit detects a second detected pulse different from the first detected pulse;
The processing unit acquires the timer value as the second detection timer value from the timer using the interrupt process after the second detected pulse is detected,
The target timer value calculation unit adds a second output time to the second detection timer value, calculates a second target timer value obtained by subtracting the error time from the addition result,
The determination unit determines whether the timer value of the timer has reached the second target timer value;
The signal output unit may output a second output signal for igniting the internal combustion engine when the timer value of the timer reaches the second target timer value.

  In the pulse signal detection circuit, the second output time may be constant regardless of the rotation speed.

An ignition device for an internal combustion engine according to an embodiment of one aspect of the present invention includes:
A rotor driven by an internal combustion engine;
Detected elements provided on the outer periphery of the rotor;
A detected pulse signal having a positive detected pulse corresponding to the front end and a negative detected pulse corresponding to the rear end is detected by detecting a front end and a rear end of the detected element. A detected pulse generator to be generated; and
The pulse signal detection circuit to which the detected pulse signal is input;
An igniter that ignites the internal combustion engine based on the first output signal or the second output signal output from the pulse signal detection circuit.

A program according to an embodiment of one aspect of the present invention is:
Computer
Timer means for measuring time by a timer value;
Detecting means for detecting a first detected pulse of the detected pulse signal;
After the first detected pulse is detected, the process being executed is interrupted to start the interrupt process, and the timer value is obtained as the first detection timer value from the timer means using the interrupt process. Processing means;
A predetermined first output time is added to the acquired first detection timer value, and from the addition result, a timing at which the first detected pulse value is detected, a timing at which the first detection timer value is acquired, and A target timer value calculating means for calculating a first target timer value obtained by subtracting a previously determined error time,
Determining means for determining whether the timer value of the timer means has reached the first target timer value;
When the timer value of the timer means reaches the first target timer value, the timer means functions as signal output means for outputting a first output signal.

In the program,
The detected pulse signal is generated according to the rotation of the internal combustion engine,
The first output signal may be a signal for igniting the internal combustion engine.

  According to the pulse signal detection method, the pulse signal detection circuit, the internal combustion engine ignition device, and the program according to one aspect of the present invention, an error that is a difference between the timing at which the detected pulse is detected and the timing at which the timer value is acquired. A target timer value is calculated by subtracting the error time from the result of adding the output time to the obtained timer value in advance. Therefore, by detecting the timing at which the timer value reaches the target timer value, it is possible to obtain an accurate timing delayed by the output time from the timing at which the detected pulse is detected. Thereby, even when an inexpensive microcomputer is used, accurate timing can be obtained.

FIG. 1 is a schematic view of an ignition device according to Embodiment 1 of the present invention. FIG. 2 is a block diagram of the pulse signal detection circuit according to the first embodiment of the present invention. FIG. 3 is a flowchart showing the operation of the pulse signal detection circuit according to the first embodiment of the present invention. FIG. 4 is a timing diagram illustrating the operation of the pulse signal detection circuit according to the first embodiment of the invention. FIG. 5 is a block diagram of a pulse signal detection circuit according to the second embodiment of the present invention. FIG. 6 is a flowchart showing the operation of the pulse signal detection circuit according to the second embodiment of the present invention. FIG. 7 is a timing chart showing the operation of the pulse signal detection circuit according to the second embodiment of the present invention. FIG. 8 is a timing chart showing the operation of the conventional pulse signal detection circuit.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic view of an ignition device according to Embodiment 1 of the present invention. As shown in FIG. 1, the ignition device includes a rotor 10, two reluctators (detected elements) 11, 12, a pickup coil (detected pulse generation unit) 13, a pulse signal detection circuit 14, and an ignition unit 15. And comprising. This ignition device is used, for example, in an internal combustion engine for a motorcycle.

The rotor 10 is attached to a crankshaft (not shown) of an internal combustion engine (not shown) and is driven by the internal combustion engine.
The two relaxers 11, 12 are provided on the outer periphery of the rotor 10 at a predetermined interval, and the relaxer 12 has a longer shape along the outer periphery of the rotor 10 than the retractor 11.

  The pickup coil 13 detects the front end portion E1 and the rear end portion E2 of the relaxer 11, and the front end portion E3 and the rear end portion E4 of the relaxer 12, and detects positive polarity detected pulses corresponding to the front end portions E1 and E3. An engine rotation pulse signal (detected pulse signal) having P1, P3 and negative detected pulses P2, P4 corresponding to the rear end portions E2, E4 is generated. As a result, the pickup coil 13 outputs an engine rotation pulse signal that repeatedly includes positive and negative detected pulses corresponding to the rotation of the crankshaft. That is, the engine rotation pulse signal includes a positive polarity detected pulse P1, a negative polarity detected pulse P2, a positive polarity detected pulse (first detected pulse) P3, and a negative polarity detected pulse (in one cycle). (Second detected pulse) P4 is generated in this order.

The pulse signal detection circuit 14 detects a predetermined detected pulse in the input engine rotation pulse signal and outputs a calculated ignition signal (first output signal) at a calculated ignition timing determined based on the detected detected pulse. The fixed ignition signal (second output signal) is output at the fixed ignition timing.
The ignition unit 15 ignites the internal combustion engine based on the fixed ignition signal or the calculated ignition signal.

  FIG. 2 is a block diagram of the pulse signal detection circuit 14 according to the first embodiment of the present invention. As shown in FIG. 2, the pulse signal detection circuit 14 includes a pulse signal generation unit 20 and a microcomputer 50. The microcomputer 50 includes a timer 21, a detection unit 22, a processing unit 23, a target timer value calculation unit 24, a determination unit 25, an ignition signal output unit (signal output unit) 26, a rotation speed calculation unit 27, An ignition output time setting unit (output time setting unit) 28, a capture detection unit 29, and a capture processing unit 30 are included. The microcomputer 50 has an input capture terminal (negative pulse input terminal) IN1 dedicated to time measurement and a general-purpose interrupt terminal (positive pulse input terminal) IN2.

  The pulse signal generator 20 includes a positive pulse signal having a first pulse P1x and a third pulse P3x respectively corresponding to detected positive pulses P1, P3 of the engine rotation pulse signal generated according to the rotation of the internal combustion engine. Then, a negative pulse signal having a second pulse P2x and a fourth pulse P4x corresponding to the detected pulses P2 and P4 of the negative polarity of the engine rotation pulse signal is generated.

  The positive pulse signal is input to the interrupt terminal IN2 of the microcomputer 50, and the microcomputer 50 performs time measurement based on the first pulse P1x and the third pulse P3x of the positive pulse signal.

  The negative pulse signal is input to the input capture terminal IN1 of the microcomputer 50, and the microcomputer 50 performs time measurement based on the second pulse P2x and the fourth pulse P4x of the negative pulse signal.

  The timer 21 is configured as a free-run timer, and measures time based on a timer value. That is, the timer 21 repeatedly counts from the initial timer value to the final timer value as the timer value.

  The detector 22 detects the first pulse P1x and the third pulse P3x of the positive pulse signal corresponding to the detected pulses P1, P3 of the engine rotation pulse signal. That is, the detection unit 22 detects the detected pulses P1 and P3 of the engine rotation pulse signal.

  After the detection unit 22 detects either the first pulse P1x or the third pulse P3x, the processing unit 23 interrupts the process being executed and starts the interrupt process. Get timer value from. The timer value acquired after the third pulse P3x is detected is the first detection timer value T1.

  The target timer value calculation unit 24 adds a predetermined calculation ignition output time (first output time) D1 to the first detection timer value T1 acquired by the processing unit 23 when the rotation speed is equal to or higher than the predetermined rotation speed. Then, an arithmetic ignition timer count value (first target timer value) C1 is calculated by subtracting a previously determined error time E from the addition result. The error time E is the difference between the timing at which one of the first pulse P1x and the third pulse P3x is detected and the timing at which the first detection timer value T1 is acquired.

  The error time E is obtained in advance as follows, for example. The detection unit 22 outputs a pulse detection signal to the outside of the microcomputer 50 at a timing at which one of the first pulse P1x and the third pulse P3x is detected. Further, the processing unit 23 outputs a timer value acquisition signal to the outside of the microcomputer 50 at the timing when the timer value is acquired from the timer 21. Then, using a measuring instrument such as an oscilloscope, the difference in time at which the pulse detection signal and the timer value acquisition signal appear is measured. Then, the measured time is converted into the count number of the timer 21 and set as the error time E in the target timer value calculation unit 24. This error time E is substantially constant regardless of the rotational speed or the like when the processing unit 23 is not executing another interrupt process. That is, the error time E may be set at the time of factory shipment.

  Further, the target timer value calculation unit 24 adds a predetermined fixed ignition output time D2 to the detection timer value T2 acquired by the capture processing unit 30 when the rotation number is lower than the predetermined rotation number. Calculate For example, the fixed ignition output time D2 is constant regardless of the rotational speed.

  The determination unit 25 determines whether or not the timer value of the timer 21 has reached the calculated ignition timer count value C1 when the rotational speed is equal to or higher than the predetermined rotational speed, and when the rotational speed is lower than the predetermined rotational speed, the timer 21 It is determined whether or not the timer value has reached the fixed ignition timer count value C2.

  Based on the control of the determination unit 25, the ignition signal output unit 26 calculates ignition that ignites the internal combustion engine when the timer value reaches the calculation ignition timer count value C1 when the rotation speed is equal to or higher than a predetermined rotation speed. Output a signal. The ignition signal output unit 26 outputs a fixed ignition signal for igniting the internal combustion engine when the timer value of the timer 21 reaches the fixed ignition timer count value C2 when the engine speed is lower than the predetermined engine speed.

The rotation speed calculation unit 27 calculates the rotation speed of the internal combustion engine based on the engine rotation pulse signal.
The ignition output time setting unit 28 sets the calculated ignition output time D1 according to the rotational speed when the rotational speed is equal to or higher than the predetermined rotational speed. The ignition output time setting unit 28 has a table in which the calculated ignition output time D1 and the rotation speed are associated with each other. The calculated ignition output time D1 is longer than the error time E.

  The capture detection unit 29 detects the second pulse P2x and the fourth pulse P4x of the negative pulse signal corresponding to the detected pulses P2, P4 of the engine rotation pulse signal. That is, the capture detection unit 29 detects the detected pulses P2 and P4 of the engine rotation pulse signal.

  The capture processing unit 30 instantaneously acquires a timer value from the timer 21 when either the second pulse P2x or the fourth pulse P4x is detected by the capture detection unit 29. The timer value acquired when the fourth pulse P4x is detected is the detection timer value T2.

  Next, the operation of the pulse signal detection circuit 14 will be described with reference to FIGS.

FIG. 3 is a flowchart showing the operation of the pulse signal detection circuit 14 according to the first embodiment of the present invention.
FIG. 4 is a timing diagram illustrating the operation of the pulse signal detection circuit 14 according to the first embodiment of the invention.

  FIG. 4 shows an engine rotation pulse signal, a negative pulse signal, a positive pulse signal, a timer value, and a calculated ignition signal. In FIG. 4, as a part of the engine rotation pulse signal, detected pulses P1 to P4 in one cycle (time t1 to t5) and the first detected pulse P1 in the next one cycle (after time t5) are shown. It is shown.

  Here, it is assumed that the timer value when the previous first pulse P1x is detected is obtained before the time t1 in FIG.

  First, the detection unit 22 detects the first pulse P1x of the positive pulse signal at time t1 shown in FIG. 4 (step S1).

  After detecting the first pulse P1x by the detection unit 22, the processing unit 23 interrupts the process being executed and starts an interrupt process (step S2). And the process part 23 acquires a timer value from the timer 21 using this interruption process (step S3).

  Based on the timer value when the previous first pulse P1x is detected and the timer value acquired this time, the rotation speed calculation unit 27 determines the interval between the previous first pulse P1x and the current first pulse P1x. (1 cycle time) is calculated (step S4).

  The rotation speed calculation unit 27 calculates the rotation speed of the internal combustion engine based on the one cycle time obtained in step S4 (step S5: seventh step).

  Note that the timer value acquired in step S3 is a value acquired at a timing delayed from the time t1 by the error time E caused by the interrupt process, but the timer value when the previous first pulse P1x is detected. Since the error time E also has an error time E, the calculated error of one cycle time is canceled out and does not cause a problem.

  Next, the detection unit 22 detects the third pulse P3x of the positive pulse signal at time t2 shown in FIG. 4 (step S6: first step).

  After the detection unit 22 detects the third pulse P3x, the processing unit 23 interrupts the process being executed and starts an interrupt process (step S7: second step).

  The processing unit 23 acquires a timer value from the timer 21 as the first detection timer value T1 by using interrupt processing at time t3 illustrated in FIG. 4 (step S8: third step). Here, the difference between the timing at which the third pulse P3x is detected (time t2) and the timing at which the first detection timer value T1 is acquired (time t3) is the error time E.

  Next, the processing unit 23 determines whether or not the rotation number calculated in step S5 is equal to or greater than a predetermined rotation number (step S9: ninth step).

  When the rotational speed is equal to or higher than the predetermined rotational speed (step S9; Yes), the processing unit 23 outputs the first detection timer value T1 to the target timer value calculation unit 24 and controls the ignition output time setting unit 28. And the ignition output time setting part 28 sets predetermined | prescribed calculation ignition output time D1 according to rotation speed (step S10: 8th step).

  Next, the target timer value calculation unit 24 adds the calculated ignition output time D1 to the first detection timer value T1 acquired in step S8, and subtracts the error time E obtained in advance from the addition result. An ignition timer count value C1 is calculated (step S11: fourth step). That is, C1 = T1 + D1-E.

  Next, the determination unit 25 determines whether or not the timer value of the timer 21 has reached the calculated ignition timer count value C1 (step S12: fifth step). If not reached (step S12; No), the determination in step S12 is repeated.

  The determination unit 25 controls the ignition signal output unit 26 when the timer value of the timer 21 reaches the calculated ignition timer count value C1 at time t4 shown in FIG. 4 (step S12; Yes). And the ignition signal output part 26 outputs the calculation ignition signal which ignites an internal combustion engine (step S13: 6th step).

  In this manner, the calculated ignition signal can be output at the accurate calculated ignition timing (time t4) delayed by the calculated ignition output time D1 from the timing (time t2) at which the third pulse P3x is detected.

  If the correction of the error time by the target timer value calculation unit 24 is not performed as described above, the calculated ignition signal is output at time t4 '(= t2 + E + D1) later than the time t4.

  Thereafter, the process returns to step S1. That is, the detection unit 22 detects the first pulse P1x next to the positive pulse signal at time t5 shown in FIG.

  On the other hand, when the rotational speed is lower than the predetermined rotational speed (step S9; No), the processing unit 23 controls the target timer value calculation unit 24 to wait for the detection timer value T2 from the capture processing unit 30. The subsequent processing is not shown in the timing diagram of FIG.

  The capture detection unit 29 detects the fourth pulse P4x of the negative pulse signal (Step S14).

  Next, the capture processing unit 30 acquires the timer value from the timer 21 as the detection timer value T2 (step S15). The capture processing unit 30 can acquire a timer value instantaneously without using interrupt processing.

  Next, the target timer value calculation unit 24 calculates a fixed ignition timer count value C2 obtained by adding a predetermined fixed ignition output time D2 to the detection timer value T2 acquired by the capture processing unit 30 in step S15 (step S16). ). The fixed ignition output time is constant regardless of the number of revolutions, for example.

  The determination unit 25 determines whether or not the timer value of the timer 21 has reached the fixed ignition timer count value C2 (step S17). If not reached (step S17; No), the determination in step S17 is repeated.

  The determination unit 25 controls the ignition signal output unit 26 when the timer value of the timer 21 reaches the fixed ignition timer count value C2 (step S17; Yes). Then, the ignition signal output unit 26 outputs a fixed ignition signal for igniting the internal combustion engine (step S18).

  At this time, since the capture processing unit 30 is used, the fixed ignition signal can be output at an accurate fixed ignition timing delayed by the fixed ignition output time D2 from the timing at which the fourth pulse P4x is detected. Thereafter, the process returns to step S1.

  As described above, according to the present embodiment, the error time E that is the difference between the timing at which the third pulse P3x is detected and the timing at which the first detection timer value T1 is acquired is obtained in advance. The calculated ignition timer count value C1 is calculated by subtracting the error time E from the result of adding the calculated ignition output time D1 to the acquired first detection timer value T1. Therefore, by detecting the timing at which the timer value reaches the calculated ignition timer count value C1, it is possible to obtain an accurate timing delayed by the calculated ignition output time D1 from the timing at which the third pulse P3x is detected. As a result, even when an inexpensive microcomputer having one input capture terminal and one interrupt terminal is used, accurate calculation ignition timing can be obtained.

  Since the error time E is subtracted in this way, even if the processing unit 23 is executing another interrupt process at the timing when the third pulse P3x is detected, the error time E It is possible to obtain a calculated ignition timing with less error than when correction is not performed as described above.

  Furthermore, since the timer 21 is a free-run timer, the first detection timer value T1 may be smaller than the error time E, but the calculated ignition output time D1 longer than the error time E is added to the first detection timer value T1. Since the error time E is subtracted from the result of adding, underflow in the arithmetic processing can be prevented. Thereby, the arithmetic processing can be easily performed.

  The present embodiment is different from the first embodiment in that the positive and negative detected pulses of the engine rotation pulse signal are detected by one interrupt terminal and the input capture terminal is not used.

  FIG. 5 is a block diagram of a pulse signal detection circuit 14a according to the second embodiment of the present invention. As illustrated in FIG. 5, the pulse signal detection circuit 14 a includes a negative pulse detection unit 40 instead of the capture detection unit 29 and the capture processing unit 30 of the pulse signal detection circuit 14 of the first embodiment illustrated in FIG. 2. The function of the processing unit 23a is different from the function of the processing unit 23 of the first embodiment shown in FIG. The microcomputer 50a has a port input terminal (negative pulse input terminal) IN3 and an interrupt terminal (positive / negative pulse input terminal) IN4. Since other circuit configurations are the same as those of the first embodiment shown in FIG. 2, the same components are denoted by the same reference numerals and description thereof is omitted.

  The pulse signal generator 20a has a first pulse P1x, a second pulse P2x, a third pulse P3x, and a fourth pulse P4x corresponding to the detected pulses P1, P2, P3, and P4 having positive polarity of the engine rotation pulse signal, respectively. A positive / negative pulse signal and a negative pulse signal having a second pulse P2x and a fourth pulse P4x respectively corresponding to the detected pulses P2 and P4 having a negative polarity of the engine rotation pulse signal are generated.

  The positive / negative pulse signal is input to the interrupt terminal IN4 of the microcomputer 50a, and the microcomputer 50a performs time measurement based on the first pulse P1x to the fourth pulse P4x of the positive / negative pulse signal.

  The negative pulse signal is input to the port input terminal IN3 of the microcomputer 50a. The negative pulse detection unit 40 of the microcomputer 50a supplies a negative pulse detection signal to the processing unit 23a when detecting either the second pulse P2x or the fourth pulse P4x of the negative pulse signal.

  After the detection unit 22 detects any one of the first pulse P1x to the fourth pulse P4x, the processing unit 23a interrupts the process being executed and starts the interrupt process. Get timer value from. The timer value acquired after the third pulse P3x is detected is the first detection timer value T1, and the timer value acquired after the fourth pulse P4x is detected is the second detection timer value T2a.

  The target timer value calculation unit 24 adds a predetermined calculation ignition output time D1 to the first detection timer value T1 acquired by the processing unit 23a as in the first embodiment when the rotation number is equal to or higher than the predetermined rotation number. The calculated ignition timer count value C1 is calculated by subtracting the error time E obtained in advance from the addition result. The error time E is obtained in advance as in the first embodiment.

  The target timer value calculation unit 24 adds a predetermined fixed ignition output time (second output time) D2a to the second detection timer value T2a acquired by the processing unit 23a when the rotation speed is lower than the predetermined rotation speed. The fixed ignition timer count value (second target timer value) C2a is calculated. This fixed ignition output time D2a is, for example, constant regardless of the rotational speed.

  Similar to the first embodiment, the determination unit 25 determines whether or not the timer value of the timer 21 has reached the calculated ignition timer count value C1 when the rotation speed is equal to or higher than the predetermined rotation speed, and the rotation speed is equal to the predetermined rotation speed. If it is lower than the number, it is determined whether or not the timer value of the timer 21 has reached the fixed ignition timer count value C2a.

  Similarly to the first embodiment, the ignition signal output unit 26 is based on the control of the determination unit 25, and when the rotation number is equal to or higher than the predetermined rotation number, the timer value of the timer 21 reaches the calculated ignition timer count value C1, An arithmetic ignition signal for igniting the internal combustion engine is output. Further, the ignition signal output unit 26 outputs a fixed ignition signal for igniting the internal combustion engine when the timer value of the timer 21 reaches the fixed ignition timer count value C2a when the engine speed is lower than the predetermined engine speed.

  Next, the operation of the pulse signal detection circuit 14a will be described with reference to FIGS.

FIG. 6 is a flowchart showing the operation of the pulse signal detection circuit 14a according to the second embodiment of the present invention.
FIG. 7 is a timing chart showing the operation of the pulse signal detection circuit 14a according to the second embodiment of the present invention.

  Steps S1 to S13 in the flowchart of FIG. 6 are the same as those in the first embodiment, and thus description thereof will be omitted. In step S2 and step S7, the processing unit 23a is not supplied with the negative pulse detection signal from the negative pulse detection unit 40. Therefore, the pulses detected in steps S1 and S6 are detected pulses P1, P3 having positive polarity. It can be recognized that the first pulse P1x and the third pulse P3x correspond to.

  FIG. 7 shows an engine rotation pulse signal, a negative pulse signal, a positive / negative pulse signal, a timer value, and a fixed ignition signal. FIG. 7 shows detected pulses P1 to P4 in one cycle (time t1a to t6a) and the first detected pulse P1 in the next cycle (after time t6a) as a part of the engine rotation pulse signal. It is shown.

  When the rotational speed is lower than the predetermined rotational speed (step S9; No), the processing unit 23a waits for the next pulse detection signal from the detection unit 22.

  The detection unit 22 detects the fourth pulse P4x of the positive / negative pulse signal at time t3a shown in FIG. 7 (step S21: tenth step). That is, the detection unit 22 detects a detected pulse (second detected pulse) P4 having a negative polarity different from the detected pulse (first detected pulse) P3 having the positive polarity detected in step S6. become. At this time, the negative pulse detection unit 40 also detects the fourth pulse P4x, and supplies a negative pulse detection signal to the processing unit 23a.

  After the fourth pulse P4x is detected and the pulse detection signal is input from the detection unit 22, the processing unit 23a interrupts the process being executed and starts an interrupt process (step S22: eleventh step). Here, when the negative pulse detection signal is supplied from the negative pulse detection unit 40, the processing unit 23a can recognize that the pulse detected at time t3a is the fourth pulse P4x.

  The processing unit 23a acquires the timer value from the timer 21 as the second detection timer value T2a by using interrupt processing at time t4a illustrated in FIG. 7 (step S23: twelfth step). Here, the difference between the timing at which the fourth pulse P4x is detected (time t3a) and the timing at which the second detection timer value T2a is acquired (time t4a) is the error time E. The error time E is obtained in advance as in the first embodiment.

  Next, the target timer value calculation unit 24 adds a predetermined fixed ignition output time D2a to the second detection timer value T2a acquired in step S23, and subtracts an error time E obtained in advance from the addition result. The fixed ignition timer count value C2a thus calculated is calculated (step S24: 13th step). That is, C2a = T2a + D2a-E.

  Next, the determination unit 25 determines whether or not the timer value of the timer 21 has reached the fixed ignition timer count value C2a (step S25: 14th step). If not reached (step S25; No), the determination in step S25 is repeated.

  The determination unit 25 controls the ignition signal output unit 26 when the timer value of the timer 21 reaches the fixed ignition timer count value C2a at time t5a shown in FIG. 7 (step S25; Yes). The ignition signal output unit 26 outputs a fixed ignition signal for igniting the internal combustion engine (step S26: 15th step).

  Thus, the fixed ignition signal can be output at the accurate fixed ignition timing (time t5a) delayed by the fixed ignition output time D2a from the timing (time t3a) at which the fourth pulse P4x is detected.

  If the error time correction by the target timer value calculation unit 24 is not performed as described above, the fixed ignition signal is output at time t5a ′ (= t3a + E + D2a) later than the time t5a.

  Thereafter, the process returns to step S1. That is, the detection unit 22 detects the first pulse P1x next to the positive / negative pulse signal at time t6a shown in FIG.

  As described above, according to the present embodiment, since only one interrupt terminal IN4 and one port input terminal IN3 are used without using the input capture terminal, the microcomputer 50a, which is cheaper than that of the first embodiment, is provided. Can be used.

  In addition, the error time E is obtained in advance, and the fixed ignition timer count value C2a is calculated by subtracting the error time E from the result of adding the fixed ignition output time D2a to the acquired second detection timer value T2a. I am doing so. Therefore, accurate fixed ignition timing can be obtained. Further, as in the first embodiment, it is possible to obtain an accurate calculated ignition timing. Furthermore, the same effects as those of the first embodiment can be obtained.

(Modification)
Various modifications can be made to the first and second embodiments. Hereinafter, an example of modification will be described. In the following description, the same reference numerals as those used for the corresponding parts in the first and second embodiments are used, and redundant description is omitted.

  In the first and second embodiments described above, an example in which the pulse signal detection circuits 14 and 14a are applied to an ignition device for an internal combustion engine has been described. However, the present invention is not limited to this, and based on detected pulses other than the internal combustion engine ignition device. It can also be applied to a device that generates a certain timing.

  In the first and second embodiments described above, the engine rotation pulse signal is detected in one cycle in the positive polarity to be detected pulse P1, the negative polarity to be detected pulse P2, the positive polarity to be detected pulse P3, and the negative polarity to be detected. Although the example which has the pulse P4 in this order was demonstrated, it is not restricted to this. That is, the number and polarity of the detected pulses may be other than those described above. Therefore, the pulse signal detection circuits 14 and 14a may generate a calculation ignition signal based on a pulse other than the third pulse P3x, and may generate a fixed ignition signal based on a pulse other than the fourth pulse P4x. Further, the pulse signal detection circuits 14 and 14a may calculate the rotation speed based on pulses other than the first pulse P1x.

  Further, the timer 21, the detection unit 22, the processing units 23 and 23a, the target timer value calculation unit 24, the determination unit 25, which constitute the microcomputers 50 and 50a described in the first and second embodiments, At least a part of the ignition signal output unit 26, the rotation speed calculation unit 27, the ignition output time setting unit 28, the capture detection unit 29, the capture processing unit 30, and the negative pulse detection unit 40 is configured by hardware. Alternatively, it may be configured by software. In the case of software configuration, a program that realizes at least a part of the functions of the above-described units constituting the microcomputers 50 and 50a is stored in a recording medium such as a flexible disk or CD-ROM, and is read by a computer and executed. You may let them. The recording medium is not limited to a removable medium such as a magnetic disk or an optical disk, but may be a fixed recording medium such as a hard disk device or a memory.

  In addition, a program that realizes at least a part of the functions of the above-described units constituting the microcomputers 50 and 50a may be distributed via a communication line (including wireless communication) such as the Internet. Further, the program may be distributed in a state where the program is encrypted, modulated or compressed, and stored in a recording medium via a wired line such as the Internet or a wireless line.

10 Rotor 11, 12 Reluctator (Detected element)
13 Pickup coil (Detected pulse generator)
14, 14a Pulse signal detection circuit 15 Ignition unit 20, 20a Pulse signal generation unit 21 Timer 22 Detection unit 23, 23a Processing unit 24 Target timer value calculation unit 25 Determination unit 26 Ignition signal output unit (signal output unit)
27 Rotational Speed Calculation Unit 28 Ignition Output Time Setting Unit (Output Time Setting Unit)
29 Capture detection unit 30 Capture processing unit 40 Negative pulse detection unit 50, 50a Microcomputer

Claims (17)

A pulse signal detection method in a pulse signal detection circuit comprising a detection unit, a processing unit, a timer, a target timer value calculation unit, a determination unit, and a signal output unit, to which a detected pulse signal is input,
A first step of detecting a first detected pulse of the detected pulse signal by the detection unit;
A second step of interrupting a process being executed and starting an interrupt process after the first detected pulse is detected by the processing unit;
A third step of acquiring a timer value as a first detection timer value from the timer in response to the detection of the first detected pulse by the processing unit using the interrupt processing;
The target timer value calculation unit adds a predetermined first output time to the acquired first detection timer value, and from the addition result, the timing at which the first detected pulse is detected and the first detection A fourth step of calculating a first target timer value obtained by subtracting a previously determined error time, which is a difference from the timing at which the timer value is acquired;
A fifth step of determining whether or not the timer value of the timer has reached the first target timer value by the determination unit;
And a sixth step of outputting a first output signal when the timer value of the timer reaches the first target timer value by the signal output unit. The detected pulse signal is generated according to the rotation of the internal combustion engine,
The pulse signal detection method according to claim 1, wherein the first output signal is a signal for igniting the internal combustion engine. The timer repeatedly counts from the initial timer value to the final timer value as the timer value,
The pulse signal detection method according to claim 2, wherein the first output time is longer than the error time. Before the first step, the engine speed calculation unit further includes a seventh step of calculating the rotation speed of the internal combustion engine based on the detected pulse signal,
The method further includes an eighth step of setting the first output time according to the rotation speed by an output time setting unit between the third step and the fourth step. The pulse signal detection method according to claim 2 or claim 3. Between the third step and the eighth step, the processing unit further includes a ninth step of determining whether the rotational speed is equal to or higher than a predetermined rotational speed,
5. The pulse signal detection method according to claim 4, wherein when the rotation speed is equal to or higher than the predetermined rotation speed in the ninth step, the process proceeds to the eighth step. When the rotation speed is lower than the predetermined rotation speed in the ninth step, the detection unit detects a second detected pulse different from the first detected pulse detected in the first step. A tenth step,
An eleventh step of interrupting a process being executed and starting an interrupt process after the second detected pulse is detected in the tenth step by the processing unit;
A twelfth step of acquiring the timer value as a second detection timer value from the timer by the processing unit using the interrupt process of the eleventh step;
The target timer value calculation unit calculates a second target timer value obtained by adding a second output time to the second detection timer value acquired in the twelfth step and subtracting the error time from the addition result. A thirteenth step,
A fourteenth step of determining whether or not the timer value of the timer has reached the second target timer value by the determination unit;
And fifteenth step of outputting a second output signal for igniting the internal combustion engine when the timer value of the timer reaches the second target timer value by the signal output unit. The pulse signal detection method according to claim 5. The pulse signal detection method according to claim 6, wherein the second output time is constant regardless of the number of rotations. A timer that measures time according to the timer value;
A detector for detecting a first detected pulse of the detected pulse signal;
After the first detected pulse is detected, the current process is interrupted to start the interrupt process, and the interrupt process is used to detect the first detected pulse from the timer. A processing unit for acquiring the timer value as a first detection timer value;
A predetermined first output time is added to the acquired first detection timer value, and from the addition result, a timing at which the first detected pulse value is detected, a timing at which the first detection timer value is acquired, and A target timer value calculator that calculates a first target timer value obtained by subtracting a previously determined error time,
A determination unit for determining whether or not the timer value of the timer has reached the first target timer value;
And a signal output unit that outputs a first output signal when the timer value of the timer reaches the first target timer value. The detected pulse signal is generated according to the rotation of the internal combustion engine,
The pulse signal detection circuit according to claim 8, wherein the first output signal is a signal for igniting the internal combustion engine. The timer repeatedly counts from the initial timer value to the final timer value as the timer value,
The pulse signal detection circuit according to claim 9, wherein the first output time is longer than the error time. A rotation speed calculation unit for calculating the rotation speed of the internal combustion engine based on the detected pulse signal;
The pulse signal detection circuit according to claim 9, further comprising: an output time setting unit that sets the first output time according to the number of rotations. The processing unit determines whether the rotational speed is equal to or higher than a predetermined rotational speed,
When the rotational speed is equal to or higher than the predetermined rotational speed,
The output time setting unit sets the first output time according to the rotation speed,
The pulse signal detection circuit according to claim 11, wherein the target timer value calculation unit calculates the first target timer value. When the rotational speed is lower than the predetermined rotational speed,
The detecting unit detects a second detected pulse different from the first detected pulse;
The processing unit acquires the timer value as the second detection timer value from the timer using the interrupt process after the second detected pulse is detected,
The target timer value calculation unit adds a second output time to the second detection timer value, calculates a second target timer value obtained by subtracting the error time from the addition result,
The determination unit determines whether the timer value of the timer has reached the second target timer value;
The pulse signal according to claim 12, wherein the signal output unit outputs a second output signal for igniting the internal combustion engine when the timer value of the timer reaches the second target timer value. Detection circuit. The pulse signal detection circuit according to claim 13, wherein the second output time is constant regardless of the rotation speed. A rotor driven by an internal combustion engine;
Detected elements provided on the outer periphery of the rotor;
A detected pulse signal having a positive detected pulse corresponding to the front end and a negative detected pulse corresponding to the rear end is detected by detecting a front end and a rear end of the detected element. A detected pulse generator to be generated; and
The pulse signal detection circuit according to any one of claims 9 to 14, wherein the detected pulse signal is input;
An ignition device for an internal combustion engine, comprising: an ignition unit that ignites the internal combustion engine based on the first output signal or the second output signal output from the pulse signal detection circuit. Computer
Timer means for measuring time by a timer value;
Detecting means for detecting a first detected pulse of the detected pulse signal;
After the first detected pulse is detected, the current processing is interrupted and interrupt processing is started, and the timer means uses the interrupt processing to correspond to the detection of the first detected pulse. Processing means for acquiring the timer value as a first detection timer value from:
A predetermined first output time is added to the acquired first detection timer value, and from the addition result, a timing at which the first detected pulse value is detected, a timing at which the first detection timer value is acquired, and A target timer value calculating means for calculating a first target timer value obtained by subtracting a previously determined error time,
Determining means for determining whether the timer value of the timer means has reached the first target timer value;
Signal output means for outputting a first output signal when the timer value of the timer means reaches the first target timer value;
Program to function as. The detected pulse signal is generated according to the rotation of the internal combustion engine,
The program according to claim 16, wherein the first output signal is a signal for igniting the internal combustion engine.

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