JP2006348775A - Internal combustion engine ignition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that necessary time for ion current detection can not be secured and accurate ion current detection is difficult with a general-purpose high output ignition device. <P>SOLUTION: In an ignition device, a primary coil constructs a second series circuit by a capacitor having one end thereof connected to a connection point with a first switching element and a second switching element, has a means charging the capacitor only when the first switching element is turned on constructed, and is provided with a means turning on a second switching element during, before or after completion of spark discharge and instantly applying charge of the capacitor on the first coil in a direction reverse to back electromotive force after start of inductive spark discharge by a spark plug connected to a secondary coil of an ignition coil by back electromotive force of the primary coil generated when the first switching element is turned off. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-power energy internal combustion engine ignition device required for a direct fuel injection internal combustion engine that is effective for measures against exhaust gas and fuel consumption, and particularly at least an internal combustion engine by detecting a change in the amount of ions caused by combustion of the internal combustion engine. The present invention relates to an internal combustion engine ignition device that is optimally combined with a combustion state detection device for an internal combustion engine that detects the occurrence of engine misfire and knocking.

  Conventionally, an internal combustion engine ignition device has been frequently used as a current interruption type ignition device. However, in order to comply with recent high-compression lean combustion for measures against exhaust gas and fuel efficiency, the energy depending on the form of the discharge current is used. Due to the shortage, double spark igniters, multi-spark igniters or alternating spark igniters have been proposed. On the other hand, the combustion state detection device for an internal combustion engine detects a continuous misfiring and detects a change in the rotational speed of the internal combustion engine at the time of misfiring with a sensor in order to indicate a warning to the operator of the internal combustion engine. A misfire detection function has been proposed.

  In addition, the combustion state detection device for an internal combustion engine using an ionic current exhibits excellent misfire detection performance even in a multi-cylinder engine in which the misfire detection accuracy is lowered by the rotation variation method, and can detect misfire for each cylinder. However, since a general high energy ignition device generally has a long discharge duration, the ion detection time is limited, which is incompatible.

  The output discharge current waveform of a conventional current interruption type internal combustion engine ignition device is a substantially triangular wave, and the maximum discharge current is large when the turn ratio of the primary wire to the secondary wire of the ignition coil is small, but the discharge continues When the time is short and the turn ratio is large, the opposite discharge current can be obtained. In a direct-injection internal combustion engine or the like in which strong eddy current combustion is performed, the current in the latter half of the triangular wave hardly contributes to the ignition of fuel due to the increased turbulence.

  In addition, in a conventional current interruption type internal combustion engine ignition device with a combustion state detection device based on ion current, a part of the ignition energy at the beginning of discharge is temporarily accumulated in a capacitor, It is used as a detection power source.

  The voltage of the ion detection power source is generally used in a range of about 70V to 300V, and the higher the voltage, the higher the SN ratio of ion detection and the degree of design freedom. The energy of the ignition device necessary for the discharge is lost.

  In recent exhaust gas countermeasures, there is a demand for a system that finely collects ion current change information from the start of the internal combustion engine to the high rotation range and controls the air-fuel ratio in combination with EGR. Although it has been confirmed that about 15 degrees after the top dead center is detected in order to detect the combustion deterioration state and knocking by the ionic current, it is confirmed that the ionic current discrimination is an important time zone. On the other hand, in order to cope with a direct fuel injection internal combustion engine with lean fuel, etc., an ignition device with high output energy is desired as a problem before control by ion current, but a general-purpose high output energy ignition device is used. In such a case, the spark discharge time becomes long, and there is a problem that sufficient time required for ion current detection cannot be taken.

  In general current interruption type ignition devices, as shown in paragraph 0004, the discharge current can be set somewhat depending on the turn ratio of the primary wire and the secondary wire of the ignition coil. In direct-injection internal combustion engines, etc., where the current is a relatively large triangular wave and combustion is strong in eddy current, the problem that the current in the latter half of the triangular wave is largely disturbed and thus hardly contributes to fuel ignition. There is.

  Furthermore, when trying to collect detailed information by ionic current, spark discharge due to voltage application in one direction of discharge by the spark plug, leakage capacitance of the ignition coil and spark plug mounting electrical circuit (in a general mounting state) The charge of about 1 to 3 KV remains at the end of the spark discharge and is accompanied by corona discharge during the ion current detection period, which has emerged as a new problem that hinders the ion current information.

  Therefore, a high output energy ignition device that repeats turn-off and turn-on of a switching element in a short time at an ignition timing cannot be solved. In addition, the AC ignition device can solve the residual charge problem of leakage capacitance by making the end of the discharge output free vibration, but an independent power supply is installed to detect the circuit and the ion current for AC. A complicated circuit configuration is required, such as switching between ignition output and ion current detection.

  An internal combustion engine ignition device according to a first aspect of the present invention includes a current interruption type ignition device including a series circuit of a power source, a primary wire ring of an ignition coil, and a first switching element. A second series circuit is constituted by a capacitor having one end connected to a connection point with the switching element and a second switching element, and means for charging the capacitor only when a current is passed through the first switching element is configured. The inductive spark discharge is started by the spark plug connected to the secondary wire ring of the ignition coil by the back electromotive force of the primary wire ring generated when the current of the first switching element is interrupted. Alternatively, by means for energizing the second switching element before and after the end, and instantaneously applying the charge of the capacitor to the primary wire in the direction opposite to the counter electromotive force, By adopting a configuration in which capacitive spark discharge is performed following inductive spark discharge at the spark plug, the discharge time can be controlled, and there is no fluctuation in the end of the discharge current, which is a disadvantage of the current interrupting method. Spark discharge can be obtained.

  According to a second aspect of the present invention, there is provided an internal combustion engine ignition device in which the timing at which the charge of the capacitor of the ignition device according to the first aspect is instantaneously applied to the primary wire ring of the ignition coil varies depending on the rotational speed of the internal combustion engine. The configuration is adapted to the operating state of the internal combustion engine.

  According to a third aspect of the present invention, there is provided an internal combustion engine igniter, wherein the charge of the capacitor is transferred to the primary line of the ignition coil from the moment of current interruption of the switching element, which is the ignition timing of the igniter according to the first and second aspects. The timing to apply to the wheel changes with a gradient within 0.7 ms to 1.5 ms when the engine speed is 1000 rpm and 0.5 ms when the engine speed is 8000 rpm. It is configured to obtain an appropriate ignition energy.

  According to a fourth aspect of the present invention, there is provided an internal combustion engine ignition device comprising: an ignition plug connected to the high voltage side of the secondary wire of the ignition coil of the ignition device according to the first, second, and third aspects; A combustion ion detection circuit of an internal combustion engine shunted by a diode on the voltage side is configured with a detection power source to solve the above-described problems.

  An internal combustion engine ignition device according to a fifth aspect of the present invention includes an ignition plug on the high voltage side of the secondary wire of the ignition coil of the ignition device according to the first, second, third, and fourth aspects. The combustion ion detection circuit of the internal combustion engine is configured with a detection power source on the low voltage side, and the above-mentioned problem is caused by setting the ion detection time to at least 15 degrees ATDC (after compression top dead center) in the practical engine rotation range. Is a solution.

  According to the present invention, a system that finely collects information on changes in ion current from the start of an internal combustion engine, which has been required in recent exhaust gas countermeasures, to a high speed range, and controls the air-fuel ratio in combination with EGR. On the other hand, in order to cope with a direct fuel injection internal combustion engine with lean fuel, etc., while ensuring a discrimination time from about 15 degrees ATDC necessary for detecting a combustion deterioration state or knocking by ion current, As a problem before control, an ignition device with high output energy is desired. However, an ignition auxiliary capacitor, its boosting power source and switching element are added to a general-purpose high output energy ignition device. The maximum ignition energy can be secured over a wide area, and at the same time, the charging problem of leakage capacitance between the secondary wheel and spark plug Those that can be optimal engine ignition device in the ion current control can be solved.

  FIG. 1 shows an embodiment of the present invention as set forth in all the claims, and the time chart of FIG. 2 shows operation waveforms of main parts for explaining this embodiment. Note that the internal combustion engine is normally used in a multi-cylinder, but for the convenience of explanation, an example with one cylinder is used.

  In FIG. 1, a diode D1, a primary ring 10 of an ignition coil Tr, a switching element Q1, and a current limiting resistor R1 are connected in series from a power connection terminal B. The diode D1 is a choke coil L1, a diode D2, and a switching element. The series circuit of the switching element Q3 and the primary coil 10 of the ignition coil Tr is also shunted by the capacitor C1. Further, a switching element Q2 for boosting is connected to the intermediate tap of the choke coil L1, a spark plug is connected to the high voltage side output of the secondary ring 20 of the ignition coil Tr, and the constant voltage side output is connected. Includes a capacitor C2 constituting an ion detection power source shunted by a constant voltage diode Zd, and a diode D3 shunted by a series circuit of a resistor R2 and a diode D4 for ion current detection, and the capacitor A series circuit of C2 and the diode D3 is shunted by the diode D5, and one end of the ion current detection register R2 is connected to the engine control ECU 40 via the ion detection circuit 30. On the other hand, the output terminal of the engine control ECU 40 is connected to the control circuit 50 of the switching element Q1 and the control circuit 60 of the switching element Q2, and one end of the output of the control circuit 50 is connected to the input terminal of the control circuit 70 of the switching element Q3. ing.

  In the timing chart of FIG. 2, from above, Q1 is the power waveform of the control circuit 50 output to the switching element Q1, Q2 is the power waveform of the control circuit 60 output to the switching element Q2, and Q3 is output to the switching element Q3. The power waveform of the control circuit 70 of the switching element Q3, i1 is the current waveform flowing through the primary ring 10, C1 is the charge / discharge voltage waveform of the capacitor C1, and P is the discharge current waveform of the spark plug. A partially simplified waveform is described.

  In response to a command from the ECU 40, the switching element Q1 is turned on at timing t1 from the control circuit 50, and current starts to flow from the power supply terminal B to the primary wire ring 10 via the diode D1, and at the same time, the oscillation output of the control circuit 60 In order for the switching element Q2 to repeatedly turn on and off, the voltage is boosted to, for example, about 400 V by the electromotive force of the choke coil L1, and charging of the capacitor C1 is repeatedly started via the diode D2.

  When the switching element Q1 is turned on, a power supply voltage (not shown), for example, 14 V supplied from the power supply terminal B is applied to the primary wire ring, and a voltage with the low voltage side of the secondary wire ring 20 as the positive electrode is induced. However, the voltage induced in the secondary wire ring 20 is partially blocked by a constant voltage diode of about 200 V, and by adjusting the turn ratio of the primary wire ring 10 and the secondary wire ring 20 of the ignition coil Tr, It is set so that a voltage of 1 kV or more necessary for discharging to the spark plug P is not generated.

  At the ignition timing t2, the switching element Q1 is turned off and the charging of the capacitor C1 is stopped. At the same time, the magnetic energy accumulated in the primary coil 10 of the ignition coil Tr is applied to the secondary coil 20 on the high voltage side. When induced by the positive electrode and a current flows through the diode D5, the spark plug P starts inductive spark discharge that does not suffer the loss due to the ion detection circuit and the detection power source configuration circuit.

  Next, when the internal combustion engine is rotating at a low speed, the spark discharge is completed before and after the end, and when the internal combustion engine is rotating at a high speed, the spark discharge is being continued, that is, during start-up or idle rotation, a sufficient discharge duration is promoted. By limiting the discharge time during rotation or high-speed rotation, the output from the control circuit 70 is output at the timing t3 at which the ion current detection can be started from about ATDC 15 degrees, and the switching element Q3 is turned on. The charge of the capacitor C1 is applied to the primary ring 10, and the low voltage side of the secondary ring 20 is output to the positive electrode, so that the capacitor C2 is instantaneously charged to the voltage of the constant voltage diode Zd, for example 200V, The first inductive spark discharge at the spark plug P is terminated, and capacitive spark discharge is performed in the direction opposite to the inductive discharge current.

  Since the change in the magnetic flux of the ignition coil Tr when the inductive spark discharge is performed is relatively slow, the discharge duration is easily influenced by the pressure and vortex near the spark plug P, and particularly the rotation of the internal combustion engine. Although it is remarkable in a state where the load is applied in a region where the number is high, the magnetic flux change at the time of capacitive spark discharge is fast, and the discharge duration is almost determined by the inductance of the primary wire 10 of the capacitor C1 and the ignition coil Tr. For example, when the capacitance value of the capacitor C1 is 1 μF and the inductance of the primary ring 10 is 3 mS, the capacity discharge time is about 0.17 mS. Naturally, the timing t3 at which the ion current detection starts from about ATDC 15 degrees is the time The time is set back.

  The inductive discharge and the capacitive discharge sufficiently expand the combustion nucleus of the internal combustion engine, and when the discharge is finished, the charge voltage 200V of the capacitance C2 is applied to both ends of the discharge electrode of the spark plug, so that the combustion ion current flows. It is taken in by the ion current detection register R2 via the diode D4, processed by the ion detection circuit 30, and then input to the ECU 40.

Based on the signal sent to the ECU 40 by the ion detection circuit 30 that captures the change in the ionic current, misfires and knocks of the internal combustion engine are detected, and the lean limit of the combustion pressure and air-fuel ratio is captured to reduce exhaust gas and improve fuel efficiency. It is useful for.

  In order to effectively detect the ion current information, it is necessary to observe the ion current detection start time from about 15 degrees ATDC at least in the practical rotational range of the internal combustion engine. The timing t3 to the ON output of the switching element Q3 depends on the number of revolutions of the internal combustion engine in order to complete the discharge time having a gradient within 0.5 ms at 0.7 rpm to 1.5 ms at a rotational speed of 1000 rpm. It has been programmed.

  When the combustion state detection function based on ion current is not used, capacitive spark discharge at timing t3 is performed after sufficient inductive spark discharge time from switching element Q1 OFF timing t1 in the entire rotation range. I can do it.

  In the above-described embodiment, the polarity of the voltage induced in the secondary wire ring 20 of the ignition coil Tr when the switching element Q1 is off is positive on the high voltage side, and the secondary wire ring 20 when the switching element Q3 is on The polarity of the induced voltage is negative on the high voltage side, but can be reversed regardless of the presence or absence of the ion current detection circuit and the detection power source.

  The current limiting register R1 connected in series to the switching element Q1 is for limiting the inflow current by controlling the switching element Q1 when a preset current is exceeded. Is omitted in the description so far, but the internal combustion engine ignition device of the present invention can be added with a protective element for limiting the back electromotive force of the primary wire wheel 10 until described. Nor. The switching elements Q1 and Q2 are not limited to ordinary transistors and SCRs, and can be appropriately selected from IGBTs, FETs, and the like.

  Further, when the internal combustion engine ignition device is applied to a multi-cylinder internal combustion engine, a circuit after the diode D2 constituting a multi-cylinder quantity by one booster power source including the choke coil L1, the switching element Q2, and the control circuit 60. It can be set as the structure which distributes electricity. In this case, the output from the control circuit 60 is preferably transmitted continuously.

The figure which shows the Example of invention 1 is an operation timing chart of the main part of the embodiment of the invention of FIG.

Explanation of symbols

10 Primary wire 20 Secondary wire 30 Ion detection circuit 40 ECU
50 Q1 control circuit 60 Q2 control circuit 70 Q3 control circuit B Power supply connection terminal P Discharge current waveform of spark plug Q1 Switching element Q2 Switching element Q3 Switching element Zd Constant voltage diode L1 Choke coil Tr Ignition coil R1 Current limiting register R2 Ion current Detection register C1 Capacitor C2 Capacitor

Claims (5)

  In a current interrupting type ignition device including a series circuit of a power source, a primary coil of an ignition coil, and a first switching element, the primary wire is connected to a capacitor having one end connected to a connection point with the first switching element and a first switching element. And a means for charging the capacitor only when a current is passed through the first switching element, and a primary line generated when the current of the first switching element is interrupted. After starting the inductive spark discharge with the spark plug connected to the secondary wire ring of the ignition coil by the back electromotive force of the ring, energizing the second switching element during or before and after the spark discharge, Capacitance subsequent to inductive spark discharge at the spark plug by means of instantaneously applying the capacitor charge to the primary ring in the direction opposite to the back electromotive force. Engine ignition apparatus being characterized in that a structure in which a spark discharge is performed.   2. The internal combustion engine ignition device according to claim 1, wherein the timing at which the electric charge of the capacitor is instantaneously applied to the primary wire ring of the ignition coil varies depending on the rotational speed of the internal combustion engine.   From the moment when the current of the first switching element is cut off, which is the ignition timing, the timing when the second switching element is energized is 0.7 ms to 1.5 ms when the internal combustion engine speed is 1000 rpm, and 0.5 ms when the engine speed is 8000 rpm. The internal combustion engine ignition device according to claim 1 or 2, wherein the internal combustion engine ignition device is configured to change with an inclination of within.   2. A combustion ion detection circuit of an internal combustion engine having an ignition plug connected to a high voltage side of a secondary wire ring of an ignition coil and shunted by a diode on a low voltage side together with a detection power source. The internal combustion engine ignition device according to claim 3.   An ignition plug is connected to the high voltage side of the secondary coil of the ignition coil, and a combustion ion detection circuit of the internal combustion engine is configured with a detection power source on the low voltage side. The internal combustion engine ignition device according to any one of claims 1 to 4, wherein the internal combustion engine ignition device is set to about 15 degrees (after compression top dead center).

Images