JP2009228501A - Ignition abnormality detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition abnormality detection device which allows utilization of a capacitor, resistor or the like of small component wattage while a potential of an ignition coil output part can be switched to be low in a short time. <P>SOLUTION: In an ignition abnormality detection device 29 for detecting an abnormal state of ignition in an ignition timing control device 21 for making ignition by an ignition plug 33 by switching ignition coil output part voltage between low and high by turning on/off a switching element TR4 while forcing a switching element driving circuit power supply voltage to act, the switching element TR4 is of a voltage drive type and is constituted so as to delay the off operation of the switching element TR4 by a capacitor C1 and a resistor R8 when the switching element driving circuit power supply voltage is set low by connecting the capacitor C1 and resistor R8 in parallel in proximity to a gate of the voltage drive type switching element TR4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition abnormality detection device for a spark ignition type internal combustion engine.

  Conventionally, as this type, there are those shown in FIGS. 6 and 7, for example. That is, the internal combustion engine is provided with an ignition timing control device 1 for controlling spark ignition. In the ignition timing control device 1, an output portion to the ignition coil 2 is supplied to a power source (battery 7) by a switching element drive circuit 3. Even if the connection with the ignition coil 2 is disconnected, the potential of the output part to the ignition coil 2 does not change.

  For this reason, in the ignition abnormality detection device 4, the detection of the connection abnormality with the ignition coil 2 is performed by detecting the flyback voltage generated by the ignition operation. That is, as shown in FIG. 7A, the switching element drive circuit power supply voltage at the part a in FIG. 6 is a constant voltage during the ignition operation, and the switching element TR2 is turned off (open) when the ignition operation is stopped. As a result, the voltage supply is stopped, and the voltage is gradually lowered by the capacitor C1 and the resistor R3.

  Further, in FIG. 6, the switching element gate voltage at the part b is set to “high” or “low” by the on / off operation of the switching element TR3, as shown in FIG. 7A. Yes. As a result, the switching element TR4 is turned on / off, and the ignition coil output voltage at the part c in FIG. 6 is set to “high” or “low” as shown in FIG. Has been.

  At this time, when the primary side of the ignition coil 2 is suddenly turned on / off, a large electromotive force is generated on the secondary side, and a spark is ignited by the spark plug 5.

  At this time, a so-called flyback voltage is generated at the primary side, that is, the ignition coil output portion voltage at the part c due to the influence from the secondary side of the ignition coil 2 in accordance with the spark ignition timing.

  When the flyback voltage is detected by the abnormality detection circuit 6 of the ignition abnormality detection device 4 and this flyback voltage is detected, it is determined to be normal, and when the flyback voltage is not detected, it is determined to be abnormal. When it is determined as abnormal, the power supply from the power source is stopped.

  Since such a flyback voltage is generated for a short time, as shown in FIG. 7B, it may be difficult to perform a voltage detection operation within the generation time. Therefore, the generation of flyback voltage is detected using the external interrupt function of the CPU.

  Further, when the ignition operation is stopped by lowering the switching element drive circuit power supply voltage, the spark plug 5 may be ignited via the ignition coil 2 if the state is rapidly changed from a high state to a low state. Therefore, when the switching element drive circuit power supply voltage is turned off by opening the switching element TR2 (off state), the switching element drive circuit power supply voltage is slowly lowered (slow off) by the capacitor C1 and the resistor R3. To work).

In addition, there exists a thing as described in patent document 1 as this other kind of thing.
JP 2002-180941 A.

  However, in such a conventional device, the capacitor C1 and the resistor R3 are provided in the vicinity of the switching element TR2 so that the switching element drive circuit power supply voltage gradually decreases (slow off operation), and the capacitor C1 Therefore, the potential of the ignition coil output section cannot be made “low” in a short time, and the capacitor C1, the resistor R3, etc. need to have a large component wattage.

  Therefore, the present invention provides an ignition abnormality detection device that can make the potential of the ignition coil output section “low” in a short time, and can use capacitors, resistors, and the like having a small component wattage. .

  In order to achieve such an object, the invention described in claim 1 applies the switching element drive circuit power supply voltage and turns the switching element on and off, thereby reducing the ignition coil output voltage to “low” and “high”. In the ignition abnormality detection device for detecting an abnormal state of ignition in the ignition timing control device that is switched between and by the ignition means, the switching element is a voltage drive type, and the voltage drive type switching By connecting a capacitor and a resistor in parallel near the gate of the element, when the switching element drive circuit power supply voltage is set to “low”, the capacitor and the resistor delay the off operation of the switching element. The present invention is characterized in that the ignition abnormality detection device is configured to be configured to perform the above.

  The invention described in claim 2 is characterized in that, in addition to the configuration described in claim 1, the connection between the switching element drive circuit and the power source is opened and closed after the energization of the ignition coil is completed.

  According to a third aspect of the present invention, in addition to the configuration according to the first aspect, the detection of the ignition coil output section voltage is performed during the energization operation in addition to the timing after the energization of the ignition coil. Features.

  According to the above-described invention, by switching the switching element on and off, the ignition coil output unit voltage is switched between “low” and “high”, and the ignition timing control device for igniting by the ignition means, In the ignition abnormality detection device that detects an abnormal state of ignition, the switching element is a voltage-driven type, and a capacitor and a resistor are connected in parallel in the vicinity of the gate of the voltage-driven type switching element, thereby switching the switching element. When the drive circuit power supply voltage is set to “low”, the capacitor and the resistor are configured to delay the OFF operation of the switching element, so that the potential of the output portion of the ignition coil can be set to “low” in a short time. At the same time, capacitors, resistors, and the like having a small component wattage can be used.

  Embodiments of the present invention will be described below.

  1 to 5 show an embodiment of the present invention.

  First, the configuration will be described. Reference numeral 11 in FIG. 1 denotes a motorcycle. The motorcycle 11 has a pipe-shaped vehicle body frame 12, and a steering handle 13 and a front wheel 14 are provided at the front portion of the vehicle body frame 12. A rear wheel 15 is provided at the rear portion of the vehicle body frame 12, and a fuel tank 16 and a seating seat 17 are supported on the upper side of the vehicle body frame 12.

  A spark ignition type internal combustion engine 18 is supported by the vehicle body frame 12 below the fuel tank 16.

  The cylinder head 19 of the internal combustion engine 18 is provided with an ignition plug 33, and an ignition timing control device 21 for controlling the ignition timing of the ignition plug 33 is provided.

  As shown in FIGS. 2 and 3, the ignition timing control device 21 has a flywheel magnet 25 that rotates integrally with the crankshaft 23 of the internal combustion engine 18 and has a plurality (11 locations) of protrusions 24 formed thereon. ing. Each of the protrusions 24 is formed at an interval of 30 ° where a protrusion is missing at one position. As shown in FIG. 3, a pickup coil 26 is provided on the crankcase 22 side so as to approach each of the protrusions 24 and detect the protrusions 24. The protrusion 24 is detected by the pickup coil 26, and this signal is transmitted to the CPU 27 (see FIG. 4).

  The pickup coil 26 is connected to a CPU 27 of the ignition timing control device 21. The CPU 27 is connected to a switching element drive circuit 28 of the ignition timing control device 21. The switching element drive circuit 28 includes a switching element TR4 and an ignition coil. 31, an abnormality detection circuit 32 is connected, and an ignition plug 33 as an “ignition means” is connected to the ignition coil 31. The switching element drive circuit 28 is connected to a battery 34 as a “power source”.

  This ignition timing control device 21 causes the switching element drive circuit power supply voltage to act and also turns on / off a switching element TR4 described later to make the ignition coil output section voltage “high” or “low” and The plug 33 is ignited. An ignition abnormality detection device 29 that detects an abnormal state of ignition of the ignition timing control device 21 is provided.

  More specifically, the CPU 27 determines the ignition timing based on a signal from the pickup coil 26 and controls the switching element drive circuit 28.

  The CPU 27 is connected to the base of the switching element TR1 via the resistor R1 of the switching element drive circuit 28, and a current corresponding to the crank pulse is applied to the switching element TR1 from the CPU 27. The collector of the switching element TR1 Is connected to the base of the switching element TR2 via the resistor R2, and the emitter of the switching element TR2 is connected to the battery 34.

  The collector of the switching element TR2 is connected to the collector of the switching element TR3 via a resistor R3, and the CPU 27 is connected to the base of the switching element TR3 via a resistor R4. A corresponding current acts on the switching element TR3. The emitter of the switching element TR3 is grounded.

  The switching element TR2 and the resistor R3 are connected to the resistor R3 and the switching element TR3 by a resistor R5 and a capacitor C2 arranged in series.

  A resistor R6 and a resistor R7 are connected in series between the capacitor C2 and the switching element TR3, and the resistor R7 is connected to the gate of the voltage-driven switching element TR4.

  The resistor R6 and the resistor R7 are grounded via the capacitor C1, and the resistor R7 and the switching element TR4 are grounded via the resistor R8. In other words, a capacitor C1 and a resistor R8 are connected in parallel in the vicinity of the gate of the switching element TR4, and the off operation of the switching element TR4 is delayed by the capacitor C1 and the resistor R8. Yes.

  Further, the collector of the switching element TR4 is connected to the CPU 27 via the abnormality detection circuit 32, and the emitter of the switching element TR4 is grounded.

  Furthermore, one end of the diode D1 is connected between the resistor R5 and the capacitor C2, and the other end of the diode D1 is connected between the switching element TR4 and the abnormality detection circuit 32. Further, one end of a diode D2 is connected between the switching element TR4 and the abnormality detection circuit 32, and the other end of the diode D2 is grounded.

  Further, a primary coil (not shown) of the ignition coil 31 is connected between the switching element TR4 and the abnormality detection circuit 32, and a secondary coil (not shown) of the ignition coil 31 is connected to the ignition plug 33. .

  As shown in FIG. 4, the CPU 27 is provided with a control unit 36 that controls the switching element drive circuit power supply voltage to be “low” in accordance with the energization end timing of the ignition coil 31. Yes. Further, the CPU 27 detects the ignition coil output section voltage when the switching element gate voltage is in the ON state and when the switching element drive circuit power supply voltage is “low” by the abnormality detection circuit 32, and When the voltage is “low” and “high” at each time, it is determined to be normal, and when the voltage is “low” and “low” at each time, a determination unit 37 is provided to determine that the voltage is abnormal. It has been.

  In FIG. 2, reference numeral 43 denotes a stator disposed inside the flywheel magnet 25, and reference numeral 44 denotes a connecting rod connected to the crankshaft 23.

  Next, the operation will be described.

  The switching element drive circuit power supply voltage is the voltage at the part a in FIG. 4 and is different from the case of “high” at all times as in the prior art. As shown in FIG. In response to the end of energization of the ignition coil 31, control is performed so as to become “low”.

  On the other hand, the switching element gate voltage is a voltage at a part b in FIG. 4 and is controlled to be “high” corresponding to the ignition operation signal from the CPU 27.

  The ignition coil output part voltage is a voltage at a part c in FIG. 4. When the switching element gate voltage becomes “high”, the switching element TR 4 is turned on (closed state). “Low”, and a current flows through the primary coil of the ignition coil 31. Next, when the gate voltage of the switching element TR4 becomes “low”, the switching element TR4 is turned off, so that the current of the primary side coil is suddenly cut off and the secondary side coil of the ignition coil 31 is suddenly cut off. A large secondary voltage is generated and ignited at a desired timing by the spark plug 33.

  At this time, as shown in FIG. 5 (a), a large secondary voltage is abruptly generated in the secondary coil, so that a so-called flyback voltage is generated in the primary coil due to this influence. .

  The CPU 27 detects that the ignition coil output section voltage is “lower” than the abnormality detection voltage at the time T1 when the switching element gate voltage is “high”, and the switching element drive circuit power supply voltage is “ At time T2 when “low”, it is detected that the output voltage of the ignition coil is “higher” than the abnormality detection voltage.

  By performing such detection, the determination unit 37 determines that the ignition is performed at a proper time and is normal.

  On the other hand, when the connection with the ignition coil 31 is broken, the ignition coil output section voltage is “lower” than the abnormality detection voltage at the time T2 when the switching element drive circuit power supply voltage is “low”. Is detected. Further, at the time point T1, as described above, it is detected that the ignition coil output section voltage is “low” from the abnormality detection voltage.

  As described above, when it is detected that the ignition coil output unit voltage is “lower” than the abnormality detection voltage at the time T1 and the time T2, the ignition is not performed. It is judged.

  When it is determined that the ignition is abnormal as described above, the CPU 27 automatically stops the ignition operation and lights a warning light (not shown) to notify the driver.

  In this way, the switching element TR4 for driving the ignition coil 31 is used as a voltage-driven switching element (FET, IGBT, etc.), and the capacitor C1 and the resistor R8 are arranged in parallel near the gate of the switching element TR4. Since it is connected, the control unit 36 sets the switching element drive circuit power supply voltage to “low” in response to the end of energization of the ignition coil 31, thereby reducing the potential of the ignition coil output unit to “low” in a short time. Can be.

  Further, since the switching element TR4 is of a voltage drive type, a capacitor C1, a resistor R8 and the like connected to the gate can be those having a small component wattage.

  Furthermore, the capacitor C1 and the resistor R8 perform a slow-off operation that prevents the switching element TR4 from being turned off suddenly, thereby preventing the primary current of the ignition coil 31 from being cut off suddenly. Thus, it is possible to prevent the ignition coil 31 from generating a high voltage.

  Further, since the voltage at the time point T1 and the time point T2 is detected without detecting the flyback voltage, it can be reliably detected whether or not the ignition control is normal.

  Further, during the abnormality detection operation, by stopping the connection of the switching element drive circuit 28 to the battery 34 (opening the connection), the ignition coil output section voltage is lowered, and the connection state or disconnection state of the ignition coil 31 is changed. It can be detected, power consumption can be reduced, and the wattage of the parts can be reduced.

  Furthermore, “open / close” of the connection between the switching element drive circuit TR 2 and the battery 7 is performed after the energization of the ignition coil 31 is completed.

  Accordingly, the switching element drive circuit TR2 can be “closed” with the power supply by the timing of starting energization to the ignition coil 31 for the next ignition operation, and energization to the ignition coil 31 can be started.

  Furthermore, the detection of the ignition coil output section voltage can be detected during the energization operation in addition to the timing after the ignition coil 31 is energized, so that the operation abnormality of the abnormality detection circuit 32 can be detected.

  That is, in the case of an abnormal operation of the abnormality detection circuit 32, the detection result of the potential of the ignition coil output section voltage is either “high only” or “low only”. And according to the present embodiment, since the detection results are “low” and “high” in the normal state, when the detection results are “high only” or “low only”, in any case, An operation abnormality of the abnormality detection circuit 32 can be detected.

  In the above embodiment, the present invention is applied to the ignition timing control device 21 of the internal combustion engine 18 of the motorcycle 11. However, the present invention is not limited to this, and can be applied to other internal combustion engines.

1 is a side view of a motorcycle according to an embodiment of the present invention. 2 is a cross-sectional view showing a crankshaft and the like of the internal combustion engine of the motorcycle according to the embodiment. FIG. It is a front view which shows the flywheel magnet and pickup coil which concern on the same embodiment. It is a circuit diagram of an ignition timing control device and the like according to the same embodiment. It is a wave form diagram which shows the voltage value in each position which concerns on the embodiment. FIG. 5 is a circuit diagram of an ignition timing control device and the like corresponding to FIG. 4 showing a conventional example. It is a wave form diagram which shows the voltage value in each position which shows the prior art example.

Explanation of symbols

11 Motorcycle
18 Internal combustion engine
21 Ignition timing control device
26 Pickup coil
27 CPU
28 Switching element drive circuit
29 Ignition abnormality detection device
31 Ignition coil
32 Abnormality detection circuit
33 Spark plug
34 battery
36 Control unit
37 Judgment part
C1 capacitor
R8 resistance
TR4 switching element

Claims (3)

Ignition timing control that switches the ignition coil output voltage between `` low '' and `` high '' by activating the switching element drive circuit power supply voltage and turning on and off the switching element, and igniting by the ignition means In the ignition abnormality detection device that detects an abnormal ignition state of the device,
The switching element is a voltage-driven type, and the switching element driving circuit power supply voltage is set to “low” by connecting a capacitor and a resistor in parallel in the vicinity of the gate of the voltage-driven switching element. An ignition abnormality detection device characterized in that the off-operation of the switching element is sometimes delayed by the capacitor and the resistor.   The ignition abnormality detection device according to claim 1, wherein opening and closing of the connection between the switching element driving circuit and the power source is performed after the ignition coil has been energized.   2. The ignition abnormality detection device according to claim 1, wherein the detection of the ignition coil output section voltage is performed during the energization operation in addition to the timing after the ignition coil is energized.

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