JP6026298B2 - Ion current detector - Google Patents

Description

The present invention relates to an ion current detection device that detects an ion current generated by combustion of an internal combustion engine such as an automobile engine.

Conventionally, there is an ion current detection device that detects from a spark plug an ion current generated in a cylinder after combustion of an internal combustion engine, and determines whether there is a knock generated in the internal combustion engine or misfire of the internal combustion engine from the detected ion current. Yes. In such an ion current detection apparatus, a secondary knock is not included in the ion current path, and a positive knock can be detected to detect a minute knock signal. For example, Japanese Patent Application Laid-Open No. 2010-116824 ( Hereinafter, “Patent Document 1”) is known.

FIG. 7 shows a circuit diagram of the ion current detection device described in Patent Document 1. In FIG. 7, in Patent Document 1, an ignition coil 1 in which a primary coil L1 and a secondary coil L2 are electromagnetically coupled, a switching element 2 that controls ON / OFF of the current of the primary coil L1, and an OFF state of the switching element 2 are disclosed. A spark plug PG that discharges toward the ground based on a high voltage induced in the secondary coil L2 during operation, a capacitor C1 and a first Zener diode ZD1, and the high voltage when the spark plug PG is discharged. And a bias circuit 3 that charges the capacitor C1 to the breakdown voltage level of the first Zener diode ZD1, and a current detection circuit 4 that detects a discharge current of the capacitor C1, Between the secondary coil L2 and the first Zener diode ZD1, the first Zener diode ZD1 is Ion current detection apparatus characterized in that a second Zener diode ZD2 to the orientation has been proposed.

JP 2010-116824 A

However, the conventional ion current detection device has the following problems. In other words, in Patent Document 1, the second Zener diode is disposed between the secondary coil and the first Zener diode in the opposite direction to the first Zener diode, so that the spark plug PG is discharged when the switching element is turned ON. It is possible to detect the ion current at a quick timing and detect a small knock signal, but the alternator noise (hereinafter referred to as “alternator noise”) generated from the alternator that supplies power to the battery and electrical parts of the car When superposed on the ionic current via the secondary coil, if the combustion state is determined using the ionic current, there is a risk that the alternator noise and the knock signal will be erroneously determined.

Moreover, in the ion current detection apparatus of patent document 1, since the charge to the capacitor | condenser for detecting an ion current is performed using the energy stored in a secondary coil, the energy loss of a secondary coil generate | occur | produces and, as a result It causes a loss of the discharge voltage of the ignition coil. In order to satisfy the required output of the ignition coil in consideration of the energy loss of the secondary coil, it is conceivable to increase the number of turns of the primary and secondary coils, but when the number of turns increases, the shape of the ignition coil There also arises a problem of increasing the size.

The present invention has been made in view of the above-described problem, and prevents the superposition of alternator noise that causes magnetic flux disturbance on the secondary coil when detecting an ionic current generated in the cylinder after combustion of the internal combustion engine. An object of the present invention is to provide an ion current detection device that can prevent energy loss of the secondary coil.

In order to solve the above problems, the present invention has the following configuration of an ion current detection device . That is, an ignition coil that functions by electromagnetically coupling a primary coil and a secondary coil, an igniter that is supplied with an ignition signal and controls a current flowing through the primary coil, a bias circuit including a Zener diode and a capacitor, and an operational amplifier In the ion current detection device comprising the ion current detection circuit provided, a connection portion between the high voltage side of the primary coil and the collector terminal of the igniter is connected via the first diode and the first resistor. Connected to a bias circuit, a low voltage side of the secondary coil is connected to a ground side, a high voltage side of the secondary coil is electrically connected to a spark plug via a second diode, and the second coil connection of the diode and the spark plug, connected as said bias circuit through a third diode and a fourth diode connected in parallel The anode of the third diode is connected to the second resistor, the third anode provided on the cathode and the fourth diode provided in the diode is connected to a third resistor, I will do it.

In the present invention, the following ion current detection device may be configured. That is, the ignition coil primary coil and the secondary coil to function are electromagnetically coupled, and igniter ignition signal to control the current flowing through the primary coil is supplied, and a bias circuit consisting of a Zener diode and a capacitor, an operational amplifier In the ion current detection device comprising the ion current detection circuit provided, a connection portion between the high voltage side of the primary coil and the collector terminal of the igniter is connected via the first diode and the first resistor. An ignition plug connected to a bias circuit, the low voltage side of the secondary coil being connected to the ground side, and the high voltage side of the secondary coil discharging a high voltage from the secondary coil via a second diode are electrically connected to, the second diode, one end of the second resistor is connected to the connection portion with the spark plug, said bias circuit The other end of the second resistor is connected, and that.

According to the above configuration, an ignition coil in which a primary coil and a secondary coil are electromagnetically coupled, an igniter that supplies an ignition signal to the primary coil, a bias circuit that includes a Zener diode and a capacitor, and an ion current that includes an operational amplifier. In the ion current detection device comprising the detection circuit, a connection portion between the high voltage side of the primary coil and the collector terminal of the igniter is connected to the bias circuit via the first diode and the first resistor. The low voltage side of the coil is connected to the ground, and the high voltage side of the secondary coil is connected to a spark plug that discharges a high voltage from the secondary coil via the second diode. Is connected to the bias circuit via a third diode and a fourth diode connected in parallel, and the anode of the third diode is When the ion current generated in the cylinder after combustion of the internal combustion engine is detected, the cathode of the third diode and the anode of the fourth diode are connected to the third resistor. It is possible to prevent superposition of alternator noise that causes magnetic flux disturbance on the secondary coil, and by determining the combustion state of the internal combustion engine from the ion waveform on which no alternator noise is superimposed, the peak of the ion waveform In the knock determination before and after the value, the alter noise signal is prevented from being erroneously determined as a knock signal, and the misfire determination after the ion waveform is reduced is prevented from being erroneously determined that combustion is continued due to the alter noise signal. An ion current detector can be realized.

In addition, the connection between the high voltage side of the primary coil and the collector terminal of the igniter is connected to the bias circuit via the first diode and the first resistor, so that the capacitor for detecting the ionic current is charged. Is performed with the energy stored in the primary coil, the energy loss of the secondary coil is improved, and the loss of the discharge voltage of the ignition coil can be prevented. Further, the low voltage side of the secondary coil is connected to the ground, and the high voltage side of the secondary coil is connected to a spark plug that discharges a high voltage from the secondary coil via the second diode, and the second diode. And the spark plug are connected to the bias circuit via a third diode and a fourth diode connected in parallel, and the anode of the third diode is connected to the second resistor, The cathode of the diode and the anode of the fourth diode are connected to the third resistor, so that the residual energy of the spark plug is removed, the discharge from the spark plug converges quickly, and the ion current can be detected quickly. Can do.

It is a figure which shows the circuit diagram of the ion current detection apparatus made into the 1st Example of this invention. It is a circuit diagram which shows the operation | movement at the time of charge to the primary coil of an ion current detection apparatus. It is a circuit diagram which shows the operation | movement at the time of the discharge from the secondary coil of an ion current detection apparatus. It is a circuit diagram which shows the operation | movement of the residual energy removal of the ignition plug of an ion current detection apparatus. It is a circuit diagram which shows the operation | movement at the time of the ion current detection of an ion current detection apparatus. It is a figure which shows the circuit diagram of the ion current detection apparatus made into the modification of this invention. It is a figure which shows the circuit diagram of the ion current detection apparatus made into patent document 1. FIG.

Hereinafter, an example showing the embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a diagram showing a circuit diagram of an ion current detector according to a first embodiment of the present invention, FIG. 2 is a circuit diagram showing an operation during charging of a primary coil of the ion current detector, and FIG. FIG. 3 is a circuit diagram showing an operation during discharge from the secondary coil of the detection device, FIG. 4 is a circuit diagram showing an operation for removing residual energy of the ignition plug of the ion current detection device, and FIG. FIG. 5 shows a circuit diagram showing the operation at the time of detection, and FIG. 6 shows a circuit diagram of an ion current detection device as a modification of the present invention.

In FIG. 1, the ion current detection device 70 includes an ignition coil 16, an igniter 20, a bias circuit 58, and an ion current detection circuit 64. The ignition coil 16 includes a primary coil 10 in which the primary winding is wound around 100 turns, a secondary coil 12 in which the secondary winding is wound around 12000 turns, and an iron core 14 made of a silicon steel plate. . The igniter 20 is composed of an IGBT (Insulated Gate Bipolar Transistor), and the bias circuit 58 is composed of a Zener diode 50a, fifth and sixth diodes 52e and 52f, a fourth resistor 54d, and a capacitor 56. Further, the ion current detection circuit 64 includes an operational amplifier 60 and a detection resistor 62.

Further, the low voltage side of the primary coil 10 is connected to the positive side of the power source 30 formed of a battery of the automobile, and the high voltage side is connected to the collector terminal of the igniter 20. Further, a connection portion between the high voltage side of the primary coil 10 and the collector terminal of the igniter 20 is connected to the bias circuit 58 via a first diode 52a and a first resistor 54a.

The anode terminal of the first diode 52a is connected to the high voltage side of the primary coil and the collector terminal of the igniter 20, and the cathode terminal is connected to the first resistor 54a. Further, the first resistor 54a is a resistor having a resistance value of 100Ω.

The gate terminal of the igniter 20 is connected to the engine ECU of the automobile, and the emitter terminal is connected to the ground. Further, the igniter 20 is supplied with an ignition signal from the engine ECU.

The low voltage side of the secondary coil 12 is connected to the ground, and the high voltage side of the secondary coil 12 is connected to the center electrode of the spark plug 40 via the second diode 52b. Further, the anode terminal of the second diode 52b is connected to the secondary coil 12, and the cathode terminal is connected to the center electrode of the spark plug 40.

In addition, a second resistor 54b and a path of the third diode 52c and a path of the fourth diode 52d are connected in parallel to a connection portion between the second diode 52b and the spark plug 40. Further, the path of the second resistor 54b and the third diode 52c and the path of the fourth diode 52d are coupled and connected to the bias circuit 58 via the third resistor 54c.

The anode terminal of the third diode 52c is connected to the connection between the second diode 52b and the spark plug 40 through the second resistor 54b, and the cathode terminal has the third resistor 54c connected thereto. To the bias circuit 58. Further, the cathode terminal of the fourth diode 52d is connected to the connection portion between the second diode 52b and the spark plug 40, and the anode terminal is connected to the bias circuit 58 via the third resistor 54c. The

The second resistor 54b is a resistor having a resistance value of 1 MΩ, and the third resistor 54c is a resistor having a resistance value of 1.1 kΩ. Further, the third resistor 54c connects the path of the fourth resistor 54d and the Zener diode 50 and the path of the capacitor 56 in parallel.

The cathode terminal of the Zener diode 50 is connected to the fourth resistor 54d, and the anode terminal is connected to the fifth diode 52e and the sixth diode 52f connected in parallel. Further, the positive terminal of the capacitor 56 is connected to the third resistor 54c, and the negative terminal is connected to the fifth diode 52e and the sixth diode 52f connected in parallel.

The anode terminal of the fifth diode 52e and the cathode terminal of the sixth diode 52f are connected to the Zener diode 50 and the capacitor 56, and the cathode terminal of the fifth diode 52e and the sixth diode 52f. The anode terminal is connected to the ground. Further, the Zener diode 50 is a Zener diode having a breakdown voltage of 270V, and the voltage charged in the capacitor 56 is limited to 270V by the breakdown voltage value of the Zener diode 50, and The capacitor 56 is a capacitor having a capacitance of 0.015 µ F.

The first resistor 54a is connected to a connection portion between the third resistor 54c, the fourth resistor 54d, and the capacitor 56. Further, the connecting portion of the Zener diode 50, the fifth and sixth diodes 52e, 52f, and the capacitor 56 is connected to the inverting input terminal of the operational amplifier 60, and the power source The non-inverting input terminal of the operational amplifier 60 and the negative power source The terminal is connected to the ground. Further, a detection resistor 62 is arranged in parallel with the inverting input terminal and the output terminal of the operational amplifier 60, and a power supply voltage is supplied to the positive power supply terminal.

Next, the operation at the time of charging the primary coil 10 of the ion current detection device will be described with reference to FIG.

2, when the ignition signal to the igniter 20 from the engine ECU is input, the power supply voltage from the power source 30 is supplied to the primary coil 10, the primary current I ₁ in the direction of arrow flow The primary coil 10 generates a primary voltage of 400 to 500V.

Next, the operation at the time of discharging from the secondary coil 12 of the ion current detection device will be described with reference to FIG.

In FIG. 3, when the ignition signal from the engine ECU to the igniter 20 is cut off, the primary current I ₁ (described in FIG. 2) flowing through the primary coil 10 is also cut off. Then, a charging current _ICH flows from the primary coil 10 to the capacitor 56 in the direction of the arrow, and is charged according to the breakdown voltage value of the Zener diode 50. The charging current I _CH will flow in the path of the primary coil 10 → the first diode 52a → the first resistor 54a → the capacitor 56. That is, the capacitor 56 is charged by the primary coil 10. Since the primary voltage generated in the primary coil 10 is 400 to 500V, the charging voltage 270V limited by the capacitor 56 can be satisfied.

Further, when the ignition signal from the engine ECU to the igniter 20 is cut off, a high voltage is generated in the secondary coil 12 by electromagnetic induction. As a result, the secondary current I ₂ flows in the direction of the arrow. The secondary current I ₂ flows through the path of the secondary coil 12 → the second diode 52 b → the spark plug 40. Further, since the second resistor 54b is provided between the third diode 52c and the second diode 52b, the discharge current from the secondary coil 12 does not flow to the capacitor 56. .

Next, the residual energy removal operation of the spark plug 40 of the ion current detection device will be described with reference to FIG.

In FIG. 4, since the ion current I _ion described later cannot be detected unless the discharge from the spark plug 40 converges, a path is provided for extracting the current accumulated in the spark plug 40 as residual energy in the direction of the arrow. ing. The residual energy is calculated as follows: the spark plug 40 → the second resistor 54b → the third diode 52c → the third resistor 54c → the fourth resistor 54d → the Zener diode 50 → the fifth diode 52e. The path is shorted to the ground.

Next, the operation at the time of ion current detection of the ion current detection device will be described with reference to FIG.

In FIG. 5, when the discharge from the secondary coil 12 to the spark plug 40 converges, the voltage across the capacitor 56 charged by the primary coil 10 in FIG. The ion current I _ion flows in the direction of the arrow. The ion current I _ion flows through the detection resistor 62 → the capacitor 56 → the third resistor 54c → the fourth diode 52d → the spark plug 40. As a result, a detection signal is output from the operational amplifier according to the detected amount of the ion current I _ion .

With the above configuration, the low voltage side of the secondary coil 12 is connected to the ground, and the high voltage side of the secondary coil 12 is connected to the spark plug 40 via the second diode 52b. As a result, the current flow from the spark plug 40 to the high voltage side of the secondary coil 12 is blocked by the second diode 52b without being influenced by the current flow to the low voltage side of the secondary coil 12. Therefore, the ion current I _ion can be prevented from being affected by the alternator noise.

In addition, a connecting portion between the high voltage side of the primary coil 10 and the collector terminal of the igniter 20 is connected to the bias circuit 58 via the first diode 52a and the first resistor 54a. As a result, the capacitor 56 for detecting the ion current I _ion is charged with the energy from the primary coil 10, so that the energy loss of the secondary coil 12 is improved and the ignition coil 16 is discharged. Voltage loss can be prevented.

In addition, the second resistor 54b and the path of the third diode 52c and the path of the fourth diode 52d are connected in parallel to the connection portion of the second diode 52b and the spark plug 40. Yes. Further, the path of the second resistor 54b and the third diode 52c and the path of the fourth diode 52d are coupled and connected to the bias circuit 58 via the third resistor 54c. Thereby, the residual energy stored in the spark plug 40 is removed, and the detection of the ionic current I _ion from the spark plug 40 can be started quickly.

As a modification of the first embodiment, the number of turns of the primary coil 10 and the secondary coil 12 is such that the output required for the ignition coil 16 can be obtained, and the bias circuit 58 If it is possible to satisfy the requirement that the capacitor 56 can be charged, the number of turns may be changed depending on design circumstances. The circuit configuration of the bias circuit 58 and the ion current detection circuit 64 is arbitrary depending on the design circumstances as long as it detects the ion current I _ion using the voltage across the capacitor as a bias power supply and outputs a detection signal from the operational amplifier. The circuit configuration may be changed. Furthermore, since the fourth diode 52d only needs to have a withstand voltage against the output from the secondary coil 12, the fourth diode 52d may be composed of a plurality of diodes.

In addition, the Zener diode 50 may be changed to a Zener diode having an arbitrary breakdown voltage according to the design circumstances in accordance with the charge amount of the capacitor 56. Further, the resistance values of the first resistor 54a, the second resistor 54b, and the third resistor 54c may be changed to resistors having arbitrary resistance values depending on design circumstances, and the capacitor 56 The capacitance may be changed to a capacitor having an arbitrary capacitance value depending on design circumstances.

In the circuit diagram of the ion current detection device according to the modification of the present invention shown in FIG. 7, the ion current detection device 70 includes the second diode 52b connected to the high voltage side of the secondary coil 12 and the spark plug. 40 is connected to the bias circuit 58 only through the second resistor 54b. In addition, since the second resistor 54b is provided between the bias circuit 58 and the second diode 52b, the discharge current from the secondary coil 12 does not flow to the capacitor 56. With this configuration, the capacitor 56 for detecting the ion current I _ion is charged with the energy from the primary coil 10, so that the energy loss of the secondary coil 12 is improved, and the ignition coil 16 The loss of the discharge voltage can be prevented, and the number of parts can be reduced because the ion current I _ion can be detected and the residual energy can be removed only by the second resistor 54b.

10: 1 primary coil
12: Secondary coil
14: Iron core
16: Ignition coil
20: Igniter
30: Power supply
40: Spark plug
50: Zener diode
52a: first diode
52b: second diode
52c: Third diode
52d: Fourth diode
52e: fifth diode
52f: Sixth diode
54a: First resistor
54b: Second resistance
54c: Third resistor
54d: Fourth resistor
56: Capacitor
58: Bias circuit
60: Operational amplifier
62: Resistance for detection
64: Ion current detection circuit
70: Ion current detector

Claims (2)

An ignition coil that functions by electromagnetically coupling a primary coil and a secondary coil, an igniter that is supplied with an ignition signal and controls a current flowing through the primary coil, a bias circuit including a Zener diode and a capacitor, and an operational amplifier . In an ion current detection device comprising an ion current detection circuit,
Connection between the collector terminal of the high-pressure side of the primary coil igniter is connected to the bias circuit through a first diode to the first resistor,
The low voltage side of the secondary coil is connected to the ground side, and the high voltage side of the secondary coil is electrically connected to the spark plug through a second diode,
The connecting portion between the spark plug and the second diode via a third diode and a fourth diode connected in parallel is connected to the bias circuit, the anode of the third diode, the is connected to the second resistor, the third anode provided on the cathode and the fourth diode provided in the diode, the ion current detecting device, characterized in that it is connected to the third resistor. An ignition coil that functions by electromagnetically coupling a primary coil and a secondary coil, an igniter that is supplied with an ignition signal and controls a current flowing through the primary coil, a bias circuit including a Zener diode and a capacitor, and an operational amplifier . In an ion current detection device comprising an ion current detection circuit,
Connection between the collector terminal of the high-pressure side of the primary coil igniter is connected to the bias circuit through a first diode to the first resistor,
The low voltage side of the secondary coil is connected to the ground side, and the high voltage side of the secondary coil is electrically connected to a spark plug that discharges a high voltage from the secondary coil via a second diode. ,
Said second diode, said second end side of the resistance of the connection between the spark plug is connected, the said bias circuit, and the other end side of the second resistor is connected Ion current detector.

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