JP2017145753A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate consumption of an electrode.SOLUTION: An ECU 100 (control device) comprises: a consumption derivation unit 112 which ignites fuel by switching between single spark ignition where an ignition plug 11 performs main discharge and multi-spark ignition where the ignition plug performs the main and auxiliary discharge and derives consumption of an ignition plug electrode due to the main discharge for the single spark ignition and the multi-spark ignition on the basis of an engine rotation speed; and a correction processing unit 114 which corrects the consumption on the basis of the number of times of the auxiliary discharge for the multi-spark ignition.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an engine control device that estimates the amount of electrode consumption of a spark plug.

  2. Description of the Related Art Conventionally, in an engine, a spark plug is attached to a cylinder head. By spark discharge of the spark plug, fuel (air mixture) flowing into the combustion chamber is ignited. The spark plug is provided with a center electrode provided at the center of the shaft and side electrodes extending from the side of the center electrode toward the center.

  Since the electrode of the spark plug is consumed due to spark discharge, maintenance is required when the consumed amount exceeds a predetermined amount. For example, in Patent Document 1, the number of discharges and discharge voltage of a spark plug are specified from a map based on the engine speed and engine load, and the ignition changes depending on the consumption of the electrode based on the specified number of discharges and discharge voltage of the spark plug. A technique for estimating a gap length between a center electrode and a side electrode of a plug is disclosed.

JP 2009-180156 A

  2. Description of the Related Art In recent years, an engine that performs multi-spark ignition that performs a plurality of spark discharges in one combustion stroke in a combustion condition in which fuel is lean is known. In contrast to single spark ignition in which only one spark discharge is performed, multi-spark ignition performs sub-discharge after the main discharge. Since the consumption amount of the electrode differs between the main discharge and the sub discharge, the technique described in Patent Document 1 described above causes an error in the estimated value of the electrode consumption amount.

  Accordingly, an object of the present invention is to provide a control device capable of accurately estimating the amount of electrode consumption.

  In order to solve the above-described problem, an engine control apparatus for igniting fuel by switching between single spark ignition in which the spark plug performs main discharge and multi-spark ignition in which the spark plug performs main discharge and sub-discharge is provided. A consumption amount deriving unit for deriving the consumption amount of the spark plug electrode due to the main discharge of the single spark ignition and the multi-spark ignition based on the engine speed, and the consumption amount based on the number of sub-discharges of the multi-spark ignition And a correction processing unit for correcting.

  The consumption amount deriving unit derives the consumption amount based on the discharge voltage of the spark plug in addition to the engine speed, and the correction processing unit calculates the consumption amount based on the discharge voltage of the ignition plug in addition to the number of sub-discharges. May be corrected.

  If the corrected consumption amount exceeds the threshold value, a notification control unit that notifies that maintenance is necessary may be further provided.

  According to the present invention, it is possible to accurately estimate the amount of electrode consumption.

It is a figure which shows the structure of an engine. It is explanatory drawing for demonstrating a spark plug. It is a functional block diagram for demonstrating ECU. It is explanatory drawing for demonstrating single spark ignition and multi spark ignition. It is a figure which shows the consumption of the electrode with respect to the travel distance of a vehicle.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a schematic diagram showing the configuration of the engine 1. However, the configuration and processing related to the present embodiment will be described in detail below, and the description of the configuration and processing unrelated to the present embodiment will be omitted.

  The engine 1 includes a cylinder block 3 in which a cylinder bore 2 is formed, and a cylinder head 4 provided above the cylinder block 3. A piston 5 is slidably disposed in the cylinder bore 2, and the piston 5 is connected to a crankshaft 7 via a connecting rod 6. In the engine 1, a space surrounded by the cylinder bore 2, the cylinder head 4, and the piston 5 is a combustion chamber 8. The engine 1 is mounted on a vehicle (not shown).

  In the cylinder head 4, an intake port 9 and an exhaust port 10 are formed so as to communicate with the combustion chamber 8, and a plug hole 12 for arranging a spark plug 11 is formed.

  The plug hole 12 is formed along the axial center of the combustion chamber 8 in the cylinder head 4 and communicates with the combustion chamber 8. The spark plug 11 is attached to the plug hole 12 so that the tip is located in the combustion chamber 8.

  The cylinder head 4 is provided with an intake valve 13 for opening and closing the intake port 9 and an exhaust valve 14 for opening and closing the exhaust port 10. The intake valve 13 is disposed in the cylinder head 4 so that the tip is located between the intake port 9 and the combustion chamber 8, and moves by the rotation of a cam (not shown) to communicate the intake port 9 with the combustion chamber 8. And close. The exhaust valve 14 is disposed in the cylinder head 4 so that the tip thereof is located between the exhaust port 10 and the combustion chamber 8, and is moved by rotation of a cam (not shown) to communicate the exhaust port 10 with the combustion chamber 8. And close.

  In the engine 1, after the air-fuel mixture flows into the combustion chamber 8 through the intake port 9, the air-fuel mixture is ignited by the spark plug 11 to burn the air-fuel mixture. The piston 5 is reciprocated in the cylinder bore 2 by the explosion pressure generated in the combustion chamber 8 by burning the air-fuel mixture, and the crankshaft 7 is rotationally driven by the reciprocation.

  FIG. 2 is an explanatory diagram for explaining the spark plug 11, and shows an extracted tip of the spark plug 11 on the combustion chamber 8 side. As shown in FIG. 2, the spark plug 11 includes a center electrode 11a and side electrodes 11b. The center electrode 11a is inserted into the plug body 11c, and the tip 11d of the center electrode 11a protrudes from the lower lower end surface 11e in FIG. 2 of the plug body 11c.

  The side electrode 11b is provided on the outer peripheral side of the lower end surface 11e of the plug main body 11c, and extends in the axial direction of the plug main body 11c. The plug main body 11c extends from the axial extension 11f. A radially extending portion 11g extending inwardly in the radial direction. A tip 11h is attached to a portion of the radially extending portion 11g that faces the tip portion 11d of the center electrode 11a in the axial direction.

  The center electrode 11a and the side electrode 11b (chip 11h) are spaced apart so as to form a predetermined discharge gap.

  When a voltage is applied to the center electrode 11a under the control of the ECU 100 (Engine Control Unit) of the engine 1, a spark discharge is generated in a discharge gap that is a gap between the tip portion 11d and the chip 11h, and air and fuel The mixture will ignite.

  FIG. 3 is a functional block diagram for explaining the ECU 100. The ECU 100 is configured by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing a program, a RAM as a work area, and the like, and controls the engine 1. Further, the ECU 100 functions as an ignition control unit 110, a consumption amount deriving unit 112, a correction processing unit 114, and a display control unit 116 (notification control unit).

  The ignition control unit 110 receives a crank angle signal indicating the crank angle (the rotation angle of the crankshaft 7) detected by the crank sensor S, and based on the crank angle signal, performs ignition discharge at a predetermined crank angle. Send an ignition signal to Here, the ignition signal includes a main discharge signal for performing main discharge and a sub-discharge signal for performing sub-discharge. The main discharge and the sub discharge will be described in detail later.

  The ignition circuit 120 has, for example, a power transistor, a primary coil, and a secondary coil. When the power transistor is turned on by an ignition signal from the ECU 100, a power supply voltage such as an alternator or a battery is applied to the primary coil. Current flows. When the power transistor is turned off, the primary coil current is cut off, thereby generating a high voltage due to mutual induction in the secondary coil. The high voltage of the secondary coil is applied to the center electrode 11a, and spark discharge is generated in the discharge gap. The electrodes (such as the chip 11h) of the spark plug 11 are consumed by spark discharge.

  Further, the ignition control unit 110 performs an ignition process. The ignition process performed by the ignition control unit 110 includes single spark ignition and multi-spark ignition, and is switched to one of the ignition processes depending on the fuel combustion conditions. For example, the ignition control unit 110 performs multi-spark ignition ignition processing under lean fuel conditions to improve the stability of fuel ignition, and single spark ignition ignition under other combustion conditions. Process.

  Spark discharge includes main discharge and sub-discharge. Single spark ignition performs main discharge once, and multi-spark ignition performs one main discharge and one or more (for example, two) sub-discharges. Do. Therefore, in one ignition process, the amount of electrode consumption differs between single spark ignition and multi-spark ignition.

  FIG. 4 is an explanatory diagram for explaining single spark ignition and multi-spark ignition. FIG. 4 (a) shows an ignition signal from the ECU 100 in single spark ignition, and FIG. The ignition signal from ECU100 in spark ignition is shown.

  As shown in FIG. 4, among the ignition signals, the main discharge signal A for performing the main discharge has a longer time than the sub discharge signal B for performing the sub discharge. That is, the application time to the primary coil for main discharge is longer than the application time to the primary coil for sub-discharge. The application time to the primary coil is approximately equal between the main discharge of the single spark ignition and the main discharge of the multi-spark ignition.

  Further, the application time to the primary coil for the sub-discharge (sub-discharge signal B) is, for example, about 25% with respect to the application time to the primary coil for the main discharge (main discharge signal A). Yes. For this reason, the sub discharge consumes less electrode than the main discharge.

  Returning to FIG. 3, the consumption amount deriving unit 112 derives the consumption amount of the electrode due to the main discharge of single spark ignition and multi-spark ignition based on the engine speed and the engine load (discharge voltage of the spark plug 11). . Here, the engine load is derived from, for example, the throttle opening.

  As described above, since the main discharge is performed once in both cases of single spark ignition and multi-spark ignition, the number of times of main discharge is specified by the engine speed. In addition, the amount of electrode consumption in the main discharge and the sub-discharge is affected by the engine load (discharge voltage of the spark plug 11). Since the discharge voltage of the spark plug 11 increases as the engine load increases, the discharge voltage is specified by the engine load.

  Therefore, for example, a main discharge map in which the consumption amount of the electrode due to the main discharge is associated with the engine speed and the engine load is stored in the memory of the ECU 100. The consumption amount deriving unit 112 specifies the consumption amount of the electrode due to the main discharge for each ignition process from the main discharge map based on the engine speed and the engine load.

  The correction processing unit 114 corrects the consumption amount of the spark plug 11 based on the number of sub-discharges of multi-spark ignition and the engine load (discharge voltage of the spark plug 11). Specifically, the correction processing unit 114 counts the number of sub-discharge signals for each ignition process among the ignition signals to the ignition circuit 120.

  The memory of the ECU 100 stores a sub-discharge map in which the number of sub-discharges and the engine load are associated with the amount of electrode consumption due to discharge. The correction processing unit 114 specifies the consumption amount of the electrode due to the sub-discharge for each ignition process from the sub-discharge map based on the count value of the sub-discharge signal and the engine load.

  As described above, since the time for the application process to the primary coil is about 25% of that in the case of the main discharge, for example, the discharge voltage is lower than that of the main discharge. The consumption of the electrode is also less than that of the main discharge. For this reason, in the sub-discharge map, the amount of electrode consumption corresponding to the same number of discharges is smaller than that in the main discharge map.

  The correction processing unit 114 corrects the consumption amount of the electrode specified by the consumption amount deriving unit 112 by adding the consumption amount of the electrode specified by the sub-discharge map. In this way, the consumption amount of the electrode in consideration of the influence of the sub-discharge by the correction is derived for each ignition process.

  The display control unit 116 integrates the derived corrected electrode consumption and determines whether the integrated value exceeds a preset threshold value. If the integrated value exceeds the threshold value, the display control unit 116 causes the display unit 122 to display that maintenance is necessary. The display unit 122 is provided in a vehicle on which the engine 1 is mounted.

  FIG. 5 is a diagram showing the amount of electrode consumption with respect to the travel distance of the vehicle. In FIG. 5, the transition of the amount of consumption of the electrode when the vehicle continues to travel only by the single spark ignition is shown by a legend X of a broken line.

  When the consumption amount of the electrode reaches the threshold value α, the discharge gap is excessively opened, so that maintenance such as replacement of the spark plug 11 is required. That is, when the vehicle continues to travel only with the single spark ignition, when the travel distance reaches the distance C, the spark plug 11 needs to be maintained.

  In addition, as shown by a one-dot chain line legend Y in FIG. 5, when multi-spark ignition is also used, the consumption of the electrodes is faster than when only single spark ignition is performed. Therefore, when performing multi-spark ignition, when the travel distance reaches a distance D shorter than the distance C, the spark plug 11 needs to be maintained. Note that the legend Y indicates an operating condition in which the electrode is consumed most quickly.

  Here, for example, when determining whether or not the maintenance of the spark plug 11 is necessary based on the travel distance of the vehicle, maintenance is required when the distance D is reached, as in the case of the legend Y where the electrodes are consumed most quickly. Judgment will be made. However, in practice, if the frequency of multi-spark ignition is low, the total length of distance that reaches the threshold value α is longer than the distance D. For this reason, when maintenance is performed uniformly when the travel distance reaches the distance D, there is a case where maintenance is performed before the threshold value α is reached, and the maintenance cost may be higher than the originally required cost.

  In the present embodiment, since the consumption amount deriving unit 112 and the correction processing unit 114 estimate the amount of electrode consumption due to single spark ignition and multi-spark ignition, when the amount of electrode consumption becomes approximately the threshold α. It can be determined that maintenance is necessary, and an increase in maintenance costs can be avoided.

  In addition, when the amount of electrode consumption is estimated based on the number of discharges of the spark plug 11 without distinguishing between single spark ignition and multi-spark ignition, an estimation error occurs when the amount of electrode consumption differs between the main discharge and the sub-discharge. Will occur. In this embodiment, the correction processing unit 114 estimates the amount of consumption of the electrode due to the sub-discharge and corrects the amount of consumption of the electrode due to the main discharge derived by the consumption amount deriving unit 112. It is possible to estimate well.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various modifications within the scope described in the claims. Needless to say, the modified examples also belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the consumption amount deriving unit 112 derives the electrode consumption amount based on the discharge voltage of the spark plug 11 in addition to the engine speed, and the correction processing unit 114 determines the number of sub-discharges. In addition, the case where the consumption amount of the electrode is corrected based on the discharge voltage of the spark plug 11 has been described. However, the consumption amount of the electrode may be derived by regarding the discharge voltage of the spark plug 11 as a preset value. However, by deriving the electrode consumption amount in consideration of the discharge voltage of the spark plug 11, the electrode consumption amount can be estimated more accurately.

  In the above-described embodiment, the case where the consumption amount deriving unit 112 and the correction processing unit 114 specify the consumption amount of the electrode using the map (main discharge map, sub discharge map) has been described. However, the consumption amount deriving unit 112 and the correction processing unit 114 may derive the consumption amount of the electrode using a preset arithmetic expression.

  In the above-described embodiment, the case where the display control unit 116 displays on the display unit 122 that the maintenance is necessary when the corrected consumption amount exceeds the threshold has been described. Processing is not essential. However, by displaying on the display unit 122, the user can easily grasp the necessity of maintenance.

  In the embodiment described above, the display control unit 116 that controls the display unit 122 is described as an example of the notification control unit. However, a speaker or the like outputs a warning sound indicating that maintenance is necessary (notification). May be.

  The present invention can be used for an engine control device that estimates the consumption amount of an electrode of a spark plug.

1 Engine 11 Spark plug 100 ECU (control device)
112 consumption amount deriving unit 114 correction processing unit 116 display control unit (notification control unit)

Claims (3)

A control device for an engine that ignites fuel by switching between a single spark ignition in which a spark plug performs main discharge, and a multi-spark ignition in which the spark plug performs main discharge and sub-discharge.
A wear amount deriving unit for deriving a wear amount of the electrode of the spark plug due to the main discharge of the single spark ignition and the multi-spark ignition based on an engine speed;
A correction processing unit for correcting the consumption amount based on the number of times of the sub-discharge of the multi-spark ignition;
A control device comprising: The consumption amount deriving unit derives the consumption amount based on the discharge voltage of the spark plug in addition to the engine speed,
The control device according to claim 1, wherein the correction processing unit corrects the consumption amount based on a discharge voltage of the spark plug in addition to the number of sub-discharges.   The control device according to claim 1, further comprising a notification control unit that notifies that maintenance is required when the corrected consumption amount exceeds a threshold value.

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