JP3577217B2 - Spark plug smoldering detector for internal combustion engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark plug smoldering detection device for an internal combustion engine, which is provided with a means for determining the presence or absence of smoldering of a spark plug applied to a spark ignition type engine, and particularly measures insulation resistance between electrodes of a spark plug with a simple configuration. Accordingly, the present invention relates to a spark plug smoldering detection device for an internal combustion engine that can detect the presence or absence of smoldering with high accuracy.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in order to reduce the number of man-hours required for periodic inspections of vehicles such as automobiles, development of a maintenance-free system (which does not require maintenance inspection and removal for the purpose) has been actively performed.
[0003]
As part of such technical development, regarding the spark plug of the internal combustion engine ignition device, the spark plug itself has excellent quality and long service life, and is reliable. It is required to have strong characteristics.
[0004]
In general, if the air-fuel ratio is continuously used in a rich (rich) state, carbon is generated and adheres to the ignition portion of the spark plug. However, the carbon deposit (including other dirt and the like) causes insulation between the housing and the center electrode. , The high voltage leaks through the carbon deposits, and a phenomenon occurs in which the spark does not fly in the gap between the spark plugs. Such a phenomenon is called “smoldering”.
[0005]
The relationship between the degree of smoldering and the insulation resistance in the spark gap is, for example, when the insulation resistance is 1 MΩ or less, the smoldering state is completely smoldering and almost no ignition is possible.
[0006]
When the insulation resistance is 1 MΩ to 10 MΩ, no ignition occurs depending on the operating conditions. When the insulation resistance is 10 MΩ or more, there is no problem even if carbon deposits are present.
[0007]
In the above example, the reason why the smoldering state in the case where the insulation resistance is 10 MΩ or more is not considered to be particularly problematic is that self-cleaning is provided through the operation of the spark plug itself.
[0008]
That is, the carbon deposited on the spark plug is increased in operating conditions to increase the plug temperature and the self-cleaning temperature (for example, about 450 ° C. for leaded gasoline and about 500 ° C. for unleaded gasoline, depending on the gasoline brand). When the temperature exceeds (−530 ° C.) or more, it burns out naturally and is cleaned.
[0009]
Thus, the vehicle speed at which the spark plug reaches the self-cleaning temperature (self-cleaning vehicle speed) naturally changes depending on the heat value of the spark plug. The heat value of a spark plug is the degree to which the heat received by the spark plug is dissipated, and a spark plug having a large degree of dissipating this heat is called a high heat value. It is called low heat value.
[0010]
Therefore, as often practiced in the market, as a countermeasure against smoldering, changing to a low heat value spark plug reduces the self-cleaning vehicle speed and reduces carbon deposits during use. This means increasing the chances of burning out.
[0011]
2. Description of the Related Art Conventionally, an apparatus for detecting smoldering of an ignition plug has been proposed, for example, in Japanese Patent Application Laid-Open No. 56-88962.
In this conventional device, the primary voltage waveform and the secondary current waveform during the discharge of the ignition coil are detected and subjected to arithmetic processing to detect the smoldering state of ignition, but the circuit configuration for smoldering detection becomes complicated. This leads to increased costs.
[0012]
In addition, for example, in the device described in Japanese Patent Publication No. 6-80312, a voltage value (or a current value) induced on the primary side or the secondary side of the ignition coil during a period of energizing the primary side of the ignition coil. Is detected, the magnitude of the coil induced signal (or the vibration component contained therein) is detected as a smoldering detection signal, and the smoldering detection signal is analyzed to determine the smoldering state of the spark plug.
[0013]
In this case, when the insulation resistance is reduced due to the smoldering of the spark plug, the current flowing through the ignition coil pulsates (or the current value changes) due to the load change, and the smoldering state of the spark plug is detected. However, the circuit configuration for smoldering detection becomes complicated, which leads to an increase in cost.
[0014]
[Problems to be solved by the invention]
As described above, the conventional ignition plug smoldering detection device for an internal combustion engine, for example, in the case of the device described in Japanese Patent Publication No. 6-80312, detects a high-frequency component generated by the insulation resistance and stray capacitance on the secondary side of the ignition coil. It is necessary to extract and compare by a complicated circuit such as a filter or an integrator, and there is a problem that the detection accuracy is hindered because the process of extracting high-frequency components is many and complicated. .
[0015]
In addition, even if the insulation resistance on the secondary side of the ignition coil is the same, since the high-frequency components generated by the engine system differ, matching work of the circuit and the judgment level is required depending on the engine. However, there is a problem that it is necessary to investigate a high-frequency component with respect to each insulation resistance in order to widely detect the smoldering level, since the relationship is not a simple proportional relation.
[0016]
Furthermore, in a system that detects high-frequency components on the primary side, although it is more advantageous in terms of withstand voltage and the like than secondary-side detection, the high-frequency components are reduced through an ignition coil composed of a transformer, so that detection processing is reduced. There was a problem of disadvantage.
[0017]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. An internal combustion that can detect the presence or absence of smoldering with high accuracy by measuring the insulation resistance between electrodes of a spark plug with a simple configuration. An object of the present invention is to provide a spark plug smoldering detector for an engine.
[0018]
[Means for Solving the Problems]
An ignition plug smoldering detection device for an internal combustion engine according to claim 1 of the present invention comprises: an ignition coil provided in an ignition device of the internal combustion engine; an ignition plug connected to a secondary side of the ignition coil; Energization control means for controlling energization of the ignition coil, voltage application means for applying a bias voltage to the secondary side of the ignition coil during a smoldering detection period except for a period during which the combustion of the internal combustion engine is continued, and secondary control of the ignition coil by the bias voltage. Voltage detecting means for detecting an induced voltage value induced on the side, and smoldering determining means for determining a smoldering state of the spark plug based on the induced voltage value. And the voltage detecting means is constituted by ion current detecting means for detecting an ion current generated by combustion around the ignition plug, and detects the ion current as an induced voltage value Things.
[0020]
In addition, the present invention Claim 2 The ignition plug smoldering detection device for an internal combustion engine according to the Claim 1 Wherein the voltage applying means comprises secondary voltage accumulating means for accumulating a secondary voltage induced on the secondary side of the ignition coil when the internal combustion engine is ignited, and applying the stored energy of the secondary voltage as a bias voltage It is.
[0021]
In addition, the present invention Claim 3 The ignition plug smoldering detection device for an internal combustion engine according to the Claim 1 In the above, the voltage applying means applies a battery voltage for supplying power to the ignition coil as a bias voltage.
[0022]
In addition, the present invention Claim 4 The ignition plug smoldering detection device for an internal combustion engine according to the Claim 3 In the above, the voltage applying means raises and lowers the battery voltage and applies it as a bias voltage.
[0023]
In addition, the present invention Claim 5 The ignition plug smoldering detection device for an internal combustion engine according to the Claim 1 , The voltage applying means is constituted by a power generator driven by the internal combustion engine, and applies the output voltage of the power generator as a bias voltage.
[0024]
In addition, the present invention Claim 6 The spark plug smoldering detection device for an internal combustion engine according to claim 1 Any one of the claims up to claim 5 In the above, the smoldering determination means determines a smoldering state in an operating region excluding an operating region based on an ideal air-fuel ratio of the internal combustion engine.
[0025]
In addition, the present invention Claim 7 The spark plug smoldering detection device for an internal combustion engine according to claim 1 Any one of the claims up to claim 5 In the above, the smoldering determination means determines a smoldering state during a non-combustion period of the internal combustion engine.
[0026]
In addition, the present invention Claim 8 The ignition plug smoldering detection device for an internal combustion engine according to the Claim 7 In the above, the smoldering determining means determines a smoldering state in a fuel cut operation region of the internal combustion engine.
[0027]
In addition, the present invention Claim 9 The spark plug smoldering detection device for an internal combustion engine according to the present invention Any one of up to claim 8 In the above, the smoldering determination means determines the smoldering state at a timing synchronized with a crank angle signal corresponding to the rotation of the internal combustion engine.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram showing a system configuration according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 100 denotes an engine serving as a main body of the internal combustion engine, and 101 denotes an ignition control device for outputting an ignition signal P.
[0029]
Reference numeral 102 denotes an ignition coil having a transformer configuration. When an ignition signal P is applied to the primary side as a primary voltage V1, an ignition secondary voltage V2 according to a winding ratio between the primary side and the secondary side is generated. appear.
The ignition control device 101 functions as an energization control unit that controls energization to the primary side of the ignition coil 102.
[0030]
Reference numeral 103 denotes an ignition plug attached to each cylinder of the engine 100, and ignites an air-fuel mixture in each cylinder by spark ignition.
The ignition control device 101, the ignition coil 102, and the ignition plug 103 are components conventionally mounted on the engine 100.
[0031]
Reference numeral 104 denotes a secondary-side voltage application device connected to the ignition coil 102, and applies a bias voltage Vc for smoldering detection to the secondary side of the ignition coil 102.
Reference numeral 105 denotes a secondary current detection device connected to the ignition coil 102, and detects an induced voltage value Vi induced on the secondary side of the ignition coil 102 by application of the bias voltage Vc as a secondary current i2.
[0032]
Reference numeral 106 denotes a smoldering determination device connected to the secondary current detection device 105, and determines the “smoldering state” of the ignition plug 103 based on the secondary current i2.
The secondary-side voltage application device 104, the secondary-side current detection device 105, and the smoldering determination device 106 are components newly added according to the present invention.
Further, the determination device 106 can be configured by an ECU (electronic control unit) including a microcomputer.
[0033]
The secondary-side voltage applying means 104 applies the bias voltage Vc to the secondary side of the ignition coil 102 in a “smoldering detection period” excluding a period during which the combustion of the engine 100 is continued.
[0034]
FIG. 2 is a circuit diagram specifically showing the ignition control device 101, the ignition coil 102, the ignition plug 103, the secondary voltage application device 104, and the secondary current detection device 105 in FIG.
[0035]
In FIG. 2, reference numeral 1 denotes a battery that supplies power to the ignition coil 102. The ignition coil 102 includes a primary winding 2a and a secondary winding 2b.
Reference numeral 3 denotes a power transistor constituting the ignition control device 101, which is connected to the primary winding 2a to cut off the primary current.
[0036]
The ignition plug 103 is connected to the high voltage side of the secondary winding 2b, and ignites an air-fuel mixture in a cylinder of the engine 100 (see FIG. 1) by applying a secondary voltage V2 for ignition.
Here, only the ignition unit for one cylinder is representatively shown, but it goes without saying that a similar ignition unit is provided for each cylinder.
[0037]
In this case, the secondary voltage application device 104 and the secondary current detection device 105 constitute an ion current detection device that detects an ion current i (secondary current i2) flowing through the ignition plug 103, and the smoldering detection is performed. It also functions as a device that performs
[0038]
The secondary side voltage application device 104 includes a capacitor 5 serving as a bias power supply connected to the low voltage side of the secondary winding 2b, and a Zener diode 6 connected in parallel to the capacitor 5.
[0039]
The capacitor 5 accumulates a secondary voltage V2 induced on the secondary side of the ignition coil 102 when the engine 100 is ignited, and sets it as a bias voltage Vc.
The Zener diode 6 has one end connected to the low voltage side of the secondary winding 2b and the other end grounded, and clamps the bias voltage Vc charged in the capacitor 5.
[0040]
The secondary-side current detecting device 105 includes a diode 7 connected to the other end of the capacitor 5 and a low-resistance device 8 for detecting an ionic current connected in parallel to the diode 7. The other ends of the diode 7 and the resistor 8 are grounded.
[0041]
When the air-fuel mixture burns around the spark plug 103, ions are generated due to the ionization effect of the combustion process.
Therefore, by applying the stored energy of the secondary voltage V2 as the bias voltage Vc of the capacitor 5, the ion current i flows, and the secondary-side current detection device 105 can detect the ion current i as the induced voltage value Vi. it can.
[0042]
Next, referring to the circuit diagrams of FIGS. 3 and 4, the waveform diagrams of FIGS. 5 and 9, the enlarged sectional views of FIGS. 6 and 7, and the equivalent circuit diagram of FIG. The circuit operation of the first embodiment of the present invention will be described.
[0043]
3 shows a path of the secondary current i2 during ignition (see a solid line), FIG. 4 shows a path of an ion current i (see a broken line), FIG. 5 shows an ion current i in a normal state, and FIG. 6 shows a spark plug 103 in a normal state. 7, FIG. 7 shows the state of the ignition plug 103 at the time of smoldering, FIG. 8 shows the equivalent circuit at the time of smoldering, and FIG. 9 shows the secondary current i2 at the time of smoldering.
[0044]
6 and 7, 100a is a combustion chamber of the engine 100, 103a is a gap between the electrodes of the ignition plug 103, 103b is an insulating portion of the ignition plug 103, and Rb is a resistance value between the electrodes of the ignition plug 103.
[0045]
In FIG. 7, C is carbon attached to the periphery of the ignition plug 103.
In FIG. 8, R is an equivalent resistor connected in parallel to the ignition plug 103, and corresponds to the resistance value Rb in FIG.
Further, in FIG. 9, iR is a leak current after the end of combustion.
[0046]
First, the operation in the case of the normal spark plug 103 shown in FIG. 6 will be described. At the ignition timing of the engine 100, when the power transistor 3 cuts off the current supply to the primary winding 2a in response to the ignition signal P, a negative secondary voltage V2 is generated on the high voltage side of the secondary winding 2b. .
[0047]
As a result, a discharge current flows along a path indicated by a solid arrow in FIG. 3, and discharge occurs between the electrodes of the ignition plug 4, so that the air-fuel mixture of the engine 100 is ignited and the capacitor 5 is charged.
At this time, the charging voltage Vc of the capacitor 5 is arbitrarily set by the Zener diode 6.
[0048]
Further, ions are generated by the ionization effect around the ignition plug 103 along with the combustion of the air-fuel mixture, so that the movement of the electrons by the positive bias voltage Vc of the capacitor 5 causes the ions to move to the path indicated by the broken arrow in FIG. The ion current i flows along.
At this time, the ion current i indicating the combustion state of the air-fuel mixture can be detected by detecting the voltage drop generated in the resistor 8 as the induced voltage value Vi.
[0049]
FIG. 5 shows the waveform of the ion current i (secondary current i2) detected in this manner.
In FIG. 5, a period A from time t1 to t3 is a combustion process period, a period A1 from time t1 to t2 is an operation period in which the bias voltage Vc is lower than the secondary voltage V2, and a period A2 from time t2 to t3 is An operation period in which the bias voltage Vc is higher than the secondary voltage V2, and a period B after time t3 are combustion termination periods.
[0050]
Normally, the resistance value Rb between the electrodes of the ignition plug 103 is considered to be infinite as shown in FIG. 6, but during the combustion period, the ions generated in the combustion process period A are present in the engine 100. The ions move due to the bias voltage Vc applied to the secondary side of the coil 102 and are detected as an ion current i.
[0051]
Here, the reason that the ion current i is not detected for a certain period A1 immediately after the ignition time t1 is that the bias voltage Vc charged in the capacitor 5 is lower than the secondary voltage V2 generated by the ignition.
[0052]
Thereafter, the secondary voltage V2 rapidly decreases during combustion, so that the ion current i can be detected when the bias voltage Vc enters the operation period A2 in which the secondary voltage V2 exceeds the secondary voltage V2.
Furthermore, when the time reaches the time t3 of the combustion end period B, no ions are present in the engine 100, so that the ion current i is not detected at all.
[0053]
On the other hand, when carbon C or the like adheres to the electrode surface of the ignition plug 103 as shown in FIG. 7, a resistor R having a resistance value Rb (several MΩ) is provided between the electrodes of the ignition plug 103 as shown in FIG. It will exist equivalently.
[0054]
Therefore, when the bias voltage Vc is applied to the secondary side of the ignition coil 103, the secondary side current i2 flows between the electrodes of the ignition plug 103.
This is generally referred to as leakage (leak) current iR.
[0055]
At this time, as shown in FIG. 9, the secondary current i2 (leakage current iR) is also detected in the period B after the end of combustion.
The secondary current i2 is input to the smoldering determination device 106 (see FIG. 1) and is used for determining the smoldering state.
[0056]
The smoldering determination device 106 determines whether the ignition plug 103 is in the smoldering state when the secondary current i2 at a level corresponding to the leak current iR is detected after a predetermined period has elapsed since the detection of the ionic current i at the combustion level. It is determined that there is.
[0057]
Thus, by measuring the secondary current i2 flowing when the bias voltage Vc is applied to the secondary side of the ignition coil 102 in the non-combustion period B, the smoldering (insulation resistance) state of the ignition plug 103 is directly detected. can do.
[0058]
Therefore, with a simple circuit configuration using an ordinary ion current detection device, even if the system of the engine 100 is different, the matching adjustment work of the circuit and the determination level is almost unnecessary, and the smoldering state can be detected. .
Further, the detection range of the degree of smoldering (insulation resistance) is wide and the detection can be performed with high accuracy.
[0059]
Here, although the capacitor 5 is used as a means for applying the bias voltage Vc to the secondary side of the ignition coil 102, the power may be supplied directly from the battery 1 or by raising and lowering it. May be used.
[0060]
Embodiment 2 FIG.
In the first embodiment, the smoldering determination condition is not particularly considered. However, in order to suppress unnecessary energy loss, the smoldering determination condition may be set to limit an area where smoldering is detected.
[0061]
FIG. 10 is a flowchart showing the smoldering determination operation according to the second embodiment of the present invention in which the smoldering determination is prohibited when the control air-fuel ratio of the engine 100 is the ideal air-fuel ratio and unnecessary energy loss is suppressed.
[0062]
Normally, the smoldering state of the ignition plug 103 is generated by carbon (unburned component) due to incomplete combustion adhering to the electrode of the ignition plug 103. Therefore, the operation is performed at an ideal air-fuel ratio (A / F = 14.7). In this case, the smoldering state of the ignition plug 103 hardly occurs. Therefore, at the ideal air-fuel ratio, it is desirable to prohibit unnecessary smolder detection.
[0063]
In FIG. 10, the smoldering determination device 106 first determines whether the current control air-fuel ratio A / F is an ideal air-fuel ratio (14.7) (step S1). If it is determined to be 7 (that is, YES), the smoldering detection control is not executed, assuming that the smoldering determination is unnecessary (step S2).
[0064]
On the other hand, in step S1, if the current operation state is the rich region or the lean region and it is determined that A / F ≠ 14.7 (that is, NO), it is in a state in which smoldering can occur. It is determined whether it is time to apply the voltage Vc (step S3).
[0065]
If it is determined that the timing is not the application timing of the bias voltage Vc (that is, NO), the standby state is established until the application timing is reached, and if it is determined that the application timing of the bias voltage Vc is reached (that is, YES), the bias voltage is applied. Vc is applied (step S4).
[0066]
Subsequently, it is determined whether or not the condition for detection of the secondary current i2 has been satisfied after the combustion is completed (step S5). If it is determined that the condition is not satisfied (that is, NO), the standby state is established until the condition is satisfied. When it is determined that the detectable condition is satisfied (that is, YES), the secondary current i2 is detected (step S6).
[0067]
Finally, it is determined whether or not the secondary current i2 is at the 0 level (more than the level of the leak current iR) (step S7). If it is determined that i2 = 0 (that is, YES), it is determined that there is no smoldering. Then, if it is determined that i2> 0 (that is, NO), it is determined that smoldering is present (step S9), and the processing routine of FIG. 10 is terminated.
[0068]
Thus, in the case of the ideal air-fuel ratio (A / F = 14.7) where smoldering is unlikely to occur, the smoldering determination processing can be prohibited without waste.
In FIG. 10, the bias voltage Vc was applied to the secondary side of the ignition coil 102 from the period before the end of the combustion. However, the end of the combustion was confirmed first, and then the bias voltage Vc was applied. You may.
[0069]
Embodiment 3 FIG.
In the second embodiment, the operating state (lean region or lean region) excluding the ideal air-fuel ratio is limited as the smoldering determination condition. However, the smoldering state may be determined during the non-combustion period of the engine 100.
[0070]
For example, in the first embodiment, smoldering detection is performed at a timing within a very limited time between combustions, so that the entire apparatus has a somewhat complicated configuration.
[0071]
However, there is also a system in which smoldering hardly occurs depending on the engine. In such an engine system, the smoldering detection processing may be executed very rarely.
[0072]
Therefore, for example, if smoldering detection is performed in the fuel cut operation region, there is no need to consider the combustion period, so that smoldering can be easily detected.
FIG. 11 is a flowchart showing a smoldering determination operation according to Embodiment 3 of the present invention in which the operating state during fuel cut is limited as a smoldering determination condition.
[0073]
In FIG. 11, steps S2, S4, and S6 to S9 are the same steps as described above.
In this case, the smoldering determination device 106 first determines whether or not the current operating state is during fuel cut (step S11). If it is determined that fuel is not being cut (that is, NO), smoldering detection control is performed. Do not execute.
[0074]
On the other hand, if it is determined in step S11 that the fuel is being cut (that is, YES), the bias voltage Vc is applied to the secondary side of the ignition coil 102 (step S4), and the secondary side current i2 is detected. (Step S6). Hereinafter, steps S7 to S9 described above are performed.
[0075]
As described above, by performing the determination of the smoldering state only in the fuel cut operation region of the engine 100, the execution frequency of the smoldering determination is further reduced, and the energy loss can be suppressed.
[0076]
Further, since the bias voltage Vc is applied to the secondary side of the ignition coil 102 during the non-combustion period of the engine 100 which performs spark discharge, the insulation resistance between the electrodes of the ignition plug 103 is directly measured, so that the configuration is simple. The device can detect smoldering of the ignition plug 103 with high accuracy.
[0077]
Embodiment 4 FIG.
In the third embodiment, the smoldering state is detected in the fuel cut operation region. However, as another detection method, the smoldering state is detected at the timing of the crank angle signal CA used for controlling the engine 100. It may be.
[0078]
FIG. 12 is a timing chart showing a smoldering determination operation according to Embodiment 4 of the present invention in which the timing of crank angle signal CA is limited as a smoldering determination condition.
In general, the timing of the crank angle signal CA can be used depending on the engine.
[0079]
In FIG. 12, a crank angle signal CA is composed of a pulse obtained from a well-known crank angle sensor, and rises at a crank angle position B 75 ° 75 ° before the top dead center TDC with respect to each of the cylinders # 1 to # 4. It falls at a crank angle position B5 ° 5 ° before the point TDC.
[0080]
In this case, the smoldering determination device 106 (see FIG. 1) detects the secondary current i2 at a timing B75 ° synchronized with the crank angle signal CA corresponding to the rotation of the engine 100, and the level of the secondary current i2 becomes 0. It is determined whether or not the ignition plug 103 is smoldering (see step S7).
[0081]
Normally, at the crank angle position B75 ° of each cylinder corresponding to the rising edge of the crank angle signal CA, the state before combustion (before the generation of the ionic current i) is in the state before the combustion, so the secondary side corresponding to the insulation resistance of the ignition plug 103 The current i2 can be reliably detected.
Therefore, the smoldering state can be detected with high accuracy with a simple configuration using the normal crank angle signal CA.
[0082]
【The invention's effect】
As described above, according to the first aspect of the present invention, the ignition coil provided in the ignition device of the internal combustion engine, the ignition plug connected to the secondary side of the ignition coil, and the energization of the primary side of the ignition coil Energizing control means for controlling, a voltage applying means for applying a bias voltage to the secondary side of the ignition coil during a smoldering detection period excluding a period during which combustion of the internal combustion engine is continued, and a voltage induced on the secondary side of the ignition coil by the bias voltage. Voltage detecting means for detecting an induced voltage value, and smoldering determining means for determining a smoldering state of a spark plug based on the induced voltage value. The voltage detecting means is constituted by an ion current detecting means for detecting an ion current generated by combustion around the spark plug, and by detecting the ion current as an induced voltage value. Since the insulation resistance between the electrodes of the spark plug is measured, there is an effect that a spark plug smoldering detection device for an internal combustion engine capable of detecting the presence or absence of smoldering with a simple configuration with high accuracy is obtained.
[0084]
In addition, the present invention Claim 2 According to Claim 1 Wherein the voltage applying means is constituted by secondary voltage accumulating means for accumulating a secondary voltage induced on the secondary side of the ignition coil when the internal combustion engine is ignited, and applying the stored energy of the secondary voltage as a bias voltage. Therefore, there is an effect that an ignition plug smoldering detection device for an internal combustion engine that can detect the presence or absence of smoldering with a simple configuration with high accuracy can be obtained.
[0085]
In addition, the present invention Claim 3 According to Claim 1 Wherein the voltage applying means applies a battery voltage for supplying power to the ignition coil as a bias voltage, so that it is possible to detect the presence or absence of smoldering with a simple configuration and to detect the presence or absence of smoldering with high accuracy in an ignition plug smoldering detection of an internal combustion engine. There is an effect that the device can be obtained.
[0086]
In addition, the present invention Claim 4 According to Claim 3 In the above, since the voltage applying means raises and lowers the battery voltage and applies it as a bias voltage, an ignition plug smoldering detection device for an internal combustion engine that can detect the presence or absence of smoldering with a simple configuration can be obtained. effective.
[0087]
In addition, the present invention Claim 5 According to Claim 1 In the above, the voltage applying means is constituted by a power generating device driven by the internal combustion engine, and applies the output voltage of the power generating device as a bias voltage. There is an effect that a spark plug smoldering detection device for an internal combustion engine that can be obtained.
[0088]
In addition, the present invention Claim 6 According to claim 1, Any one of the claims up to claim 5 In the smoldering determination means, the smoldering state is determined in an operating region other than the operating region based on the ideal air-fuel ratio of the internal combustion engine, so with a simple configuration, the presence or absence of smoldering is detected with high accuracy and energy loss is reduced. There is an effect that a suppressed ignition plug smoldering detection device for an internal combustion engine can be obtained.
[0089]
In addition, the present invention Claim 7 According to claim 1, Any one of the claims up to claim 5 In the above, the smoldering determination means determines the smoldering state during the non-combustion period of the internal combustion engine, so that the presence or absence of smoldering can be detected with high accuracy with a simple configuration, and the ignition plug smoldering of the internal combustion engine with suppressed energy loss There is an effect that a detection device can be obtained.
[0090]
In addition, the present invention Claim 8 According to Claim 7 In the above, the smoldering determination means is configured to determine the smoldering state in the fuel cut operation region of the internal combustion engine, so that the presence of smoldering can be detected with a simple configuration with high accuracy, and the ignition of the internal combustion engine with reduced energy loss can be performed. There is an effect that a plug smoldering detection device can be obtained.
[0091]
In addition, the present invention Claim 9 According to claim 1, Any one of up to claim 8 In the above, the smoldering determination means determines the smoldering state at a timing synchronized with a crank angle signal corresponding to the rotation of the internal combustion engine, so that the presence of smoldering can be detected with a simple configuration with high accuracy. Thus, there is an effect that a spark plug smoldering detecting device of the present invention can be obtained.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a system configuration according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram specifically showing a configuration of the first embodiment of the present invention.
FIG. 3 is a circuit diagram showing a path of a secondary current at the time of ignition according to the first embodiment of the present invention.
FIG. 4 is a circuit diagram showing a path of an ion current at the time of ignition according to the first embodiment of the present invention.
FIG. 5 is a waveform chart showing ion current in a normal state according to the first embodiment of the present invention.
FIG. 6 is an enlarged sectional view showing a state of the spark plug in a normal state according to the first embodiment of the present invention.
FIG. 7 is an enlarged sectional view showing a state of the ignition plug when smoldering occurs according to the first embodiment of the present invention.
FIG. 8 is an equivalent circuit diagram when smoldering occurs according to the first embodiment of the present invention.
FIG. 9 is a waveform chart showing a secondary current when smoldering occurs according to the first embodiment of the present invention.
FIG. 10 is a flowchart showing a smoldering determination operation according to Embodiment 2 of the present invention.
FIG. 11 is a flowchart showing a smoldering determination operation according to Embodiment 3 of the present invention.
FIG. 12 is a timing chart showing a smoldering determination operation according to Embodiment 4 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery, 2a primary winding, 2b secondary winding, 3 power transistor, 5 capacitor (secondary voltage storage means), 101 ignition control device (energization control means), 102 ignition coil, 103 ignition plug, 104 secondary side Voltage application device, 105 Secondary side current detection device (voltage detection means), 106 Smoldering determination device, A combustion process period, B combustion end period, B75 ° smoldering detection timing, C carbon, CA crank angle signal, i ion current I2 secondary current, Vc bias voltage, Vi induced voltage value, V2 secondary voltage, S1 step of determining ideal air-fuel ratio, S2 step of inhibiting smoldering detection, S6 step of detecting secondary current, S7 smoldering Determining whether smoldering is present, S8 determining whether smoldering is not performed, S9 determining smoldering being present, Determining 11 the fuel cut operation region.

Claims (9)

An ignition coil provided in an ignition device of the internal combustion engine,
A spark plug connected to the secondary side of the ignition coil;
Energization control means for controlling energization to the primary side of the ignition coil,
Voltage applying means for applying a bias voltage to the secondary side of the ignition coil during a smoldering detection period excluding a period during which the combustion of the internal combustion engine is continued,
Voltage detection means for detecting an induced voltage value induced on the secondary side of the ignition coil by the bias voltage,
Smoldering determination means for determining a smoldering state of the spark plug based on the induced voltage value ,
The voltage detecting means,
Ion current detection means for detecting an ion current generated by combustion around the ignition plug,
An ignition plug smoldering detection device for an internal combustion engine, wherein the ionic current is detected as the induced voltage value . The voltage applying means,
It is constituted by secondary voltage accumulating means for accumulating a secondary voltage induced on a secondary side of the ignition coil at the time of ignition of the internal combustion engine,
2. The apparatus according to claim 1 , wherein the stored energy of the secondary voltage is applied as the bias voltage. The ignition plug smoldering detection device for an internal combustion engine according to claim 1 , wherein the voltage application unit applies a battery voltage for supplying power to the ignition coil as the bias voltage. 4. The ignition plug smoldering detection apparatus for an internal combustion engine according to claim 3 , wherein the voltage application unit raises and lowers the battery voltage and applies the battery voltage as the bias voltage. The voltage applying means,
A power generator driven by the internal combustion engine,
The apparatus according to claim 1 , wherein an output voltage of the power generator is applied as the bias voltage. The internal combustion engine according to any one of claims 1 to 5 , wherein the smoldering determination means determines the smoldering state in an operation region other than an operation region based on an ideal air-fuel ratio of the internal combustion engine. Engine spark plug smoldering detector. 6. The ignition plug smoldering detection device for an internal combustion engine according to claim 1 , wherein the smoldering determination means determines the smoldering state during a non-combustion period of the internal combustion engine. The ignition plug smoldering detection device for an internal combustion engine according to claim 7 , wherein the smoldering determination means determines the smoldering state in a fuel cut operation region of the internal combustion engine. The internal combustion engine according to any one of claims 1 to 8 , wherein the smoldering determination means determines the smoldering state at a timing synchronized with a crank angle signal corresponding to the rotation of the internal combustion engine. Engine spark plug smoldering detector.

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