JP2010019114A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce frequency of occurrence of knocking and frequency of unnecessary drop of output torque. <P>SOLUTION: Base ignition timing is set according to load and engine speed NE. Ignition timing is controlled at intervals Nint to be retarded from base ignition timing. At least one of the interval Nint for retarding ignition timing and retarded angle quantity Qrtd of ignition timing are changed according to at least one of engine speed NE and engine load. When MBT is set to the base ignition timing, control for retarding ignition timing intermittently with the interval Nint is interrupted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to ignition so as to be intermittently retarded from a basic ignition timing set according to at least one of an output shaft speed and a load of the internal combustion engine. It relates to technology to control the timing.

  Conventionally, an internal combustion engine that burns an air-fuel mixture in a combustion chamber of a cylinder is known. In internal combustion engines, it is also known that knocking occurs when the air-fuel mixture burns. Knock is likely to occur when the temperature in the combustion chamber is high. Therefore, in order to reduce the temperature in the combustion chamber, when knocking occurs, the ignition timing is retarded. When the ignition timing is retarded, the combustion temperature of the air-fuel mixture decreases. As a result, the temperature in the combustion chamber decreases. As a result, knocking is suppressed.

  However, when the ignition timing is retarded, that is, when the combustion temperature of the air-fuel mixture is lowered, the output torque of the internal combustion engine can also be lowered. In order to prevent a decrease in output torque, a technique has been proposed in which the frequency with which the ignition timing is retarded when knocking occurs is reduced.

  Japanese Patent Laying-Open No. 2003-3941 (Patent Document 1) calculates the basic ignition timing based on the operating state of the internal combustion engine and responds to the occurrence state in order to suppress the occurrence of knocking (knock) of the engine. Disclosed is an ignition timing control device for an internal combustion engine that learns a retard amount and controls the engine ignition timing while reflecting the learned retard amount in the basic ignition timing. This ignition timing control device thins out the reflection of the learned retard amount to the basic ignition timing every predetermined number of ignitions.

According to the ignition timing control apparatus described in this publication, when the ignition timing is retarded with the occurrence of knocking, the reflection of the retard amount in the basic ignition timing is thinned out every predetermined number of times of ignition. The decrease in engine torque is suppressed by the amount that the ignition timing in the ignition in which the reflection of the retard amount is thinned out becomes the advance side. For this reason, it is possible to more easily achieve both the suppression of the occurrence of knocking and the suppression of the unnecessary decrease in engine torque.
JP 20033941 A

  However, in the ignition timing control device described in Japanese Patent Application Laid-Open No. 2003-3941, the retard amount is small when knocking does not occur, so that it is likely that knocking is likely to occur again. Therefore, there is room for further improvement from the viewpoint of reducing the frequency of occurrence of knocking. Also, time is required to learn the retard amount in accordance with the occurrence of knocking. Therefore, even when the operation state of the internal combustion engine is an operation state in which knocking cannot occur, the ignition timing can be retarded unnecessarily until learning of the retard amount is completed. In this case, the output torque of the internal combustion engine can be reduced unnecessarily.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to determine the ignition timing of an internal combustion engine that can reduce the frequency at which knocking occurs and the frequency at which output torque is unnecessarily reduced. It is to provide a control device.

  An ignition timing control device for an internal combustion engine according to a first aspect of the invention includes means for setting a basic ignition timing in accordance with at least one of the output shaft speed and load of the internal combustion engine, and ignition at the basic ignition timing. Means for controlling the ignition timing, retarding means for controlling the ignition timing so as to retard the basic ignition timing at predetermined intervals, intervals and ignition timing for retarding the ignition timing Means for changing at least one of the amounts of retarding the angle in accordance with at least one of the output shaft rotational speed and the load of the internal combustion engine, and the output torque of the internal combustion engine being maximized And a means for interrupting the control of the ignition timing so as to be retarded at a predetermined interval when the predetermined ignition timing is set to the basic ignition timing.

  According to this configuration, the ignition timing is controlled so that ignition is performed at the basic ignition timing set according to at least one of the output shaft speed and the load of the internal combustion engine. The ignition timing is controlled so as to be retarded from the basic ignition timing at a predetermined interval. Thereby, the ignition timing can be retarded intermittently regardless of whether or not knocking has occurred. Therefore, the temperature in the combustion chamber of the cylinder can be reduced. As a result, the frequency of occurrence of knocking can be reduced. Further, since the ignition timing is retarded intermittently, the average value of the output torque can be increased compared to the case where the ignition timing is retarded continuously. At least one of the interval for retarding the ignition timing and the amount for retarding the ignition timing is changed according to at least one of the output shaft speed and the load of the internal combustion engine. Thus, in a state where knocking is likely to occur, the interval for retarding the ignition timing can be reduced or the amount of retarding can be increased to make it difficult for knocking to occur. When the ignition timing determined so that the output torque of the internal combustion engine is maximized is set to the basic ignition timing, the control of the ignition timing is interrupted so as to be retarded at a predetermined interval. Thereby, when MBT (Minimum advance for Best Torque) is set to the basic ignition timing, that is, in a state where knocking cannot occur, the ignition timing delay can be immediately interrupted. Therefore, the frequency at which the ignition timing is retarded unnecessarily can be reduced. As a result, it is possible to provide an ignition timing control device for an internal combustion engine that can reduce the frequency at which knocking occurs and the frequency at which output torque is unnecessarily reduced.

  An ignition timing control device for an internal combustion engine according to a second aspect of the invention includes means for determining whether knock has occurred, an interval for retarding the ignition timing, and an ignition timing in addition to the configuration of the first aspect of the invention. And changing means for changing at least one of the retarded amounts according to the occurrence of knocking.

  According to this configuration, at least one of the interval for retarding the ignition timing and the amount for retarding the ignition timing is changed in accordance with the knocking occurrence state. Thereby, when knocking occurs, it is possible to make the knocking difficult to occur by reducing the interval for retarding the ignition timing or increasing the retarding amount.

  In the ignition timing control apparatus for an internal combustion engine according to the third aspect of the invention, in addition to the configuration of the second aspect, the changing means reduces the interval for retarding the ignition timing as the frequency of occurrence of knocking increases. Including means.

  According to this configuration, the frequency of retarding the ignition timing can be increased as the frequency of occurrence of knocking is increased. Therefore, it is possible to make it difficult for knocking to occur.

  In the ignition timing control device for an internal combustion engine according to the fourth invention, in addition to the configuration of the second invention, the changing means increases the amount of retarding the ignition timing as the frequency of occurrence of knocking increases. Including means.

  According to this configuration, the amount of retarding the ignition timing is increased as the frequency of occurrence of knocking increases. Therefore, it is possible to make it difficult for knocking to occur.

  An ignition timing control device for an internal combustion engine according to a fifth aspect of the invention adds the basic ignition timing so that the ignition timing becomes slower as the frequency of occurrence of knocking increases in addition to the configuration of any of the second to fourth aspects of the invention. Means for correcting are further provided.

  According to this configuration, the basic ignition timing is corrected so that the ignition timing is delayed as the frequency of occurrence of knocking increases. Thereby, in addition to retarding the ignition timing intermittently, the ignition timing can be retarded as a whole. Therefore, it is possible to make it difficult for knocking to occur.

  An ignition timing control device for an internal combustion engine according to a sixth aspect of the invention adds to the configuration of any one of the second to fifth aspects of the invention, and delays the ignition timing from the basic ignition timing at a predetermined interval when a knock occurs. Means are further provided for controlling the ignition timing to be retarded by the same amount as when making an angle.

  According to this configuration, when knocking occurs, the ignition timing is retarded by the same amount as when the ignition timing is retarded from the basic ignition timing at a predetermined interval. Thereby, in addition to retarding the ignition timing intermittently, the ignition timing can be temporarily retarded. Therefore, it is possible to make it difficult for knocking to occur.

  An ignition timing control device for an internal combustion engine according to a seventh aspect of the invention adds to the configuration of any one of the second to fifth aspects of the invention, and delays the ignition timing from the basic ignition timing at a predetermined interval when a knock occurs. There is further provided means for controlling the ignition timing to be retarded by an amount different from that when the corner is turned.

  According to this configuration, when knocking occurs, the ignition timing is retarded by an amount different from that when the ignition timing is retarded from the basic ignition timing at a predetermined interval. Thereby, in addition to retarding the ignition timing intermittently, the ignition timing can be temporarily retarded. Therefore, it is possible to make it difficult for knocking to occur.

  In the ignition timing control device for an internal combustion engine according to the eighth invention, in addition to the configuration of any one of the first to seventh inventions, the internal combustion engine is provided with a plurality of cylinders. The retarding means includes means for controlling the ignition timing so as to retard the basic ignition timing at the predetermined interval and in order in each cylinder.

  According to this configuration, the ignition timing is retarded in order in each cylinder, rather than retarding the ignition timing simultaneously in each cylinder. As a result, the interval at which the ignition timing is retarded can be made substantially uniform throughout the internal combustion engine. Therefore, the intervals at which the output torque varies during one rotation of the output shaft of the internal combustion engine can be made substantially uniform. As a result, the vibration that can occur due to the retard of the ignition timing can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, an engine 100 whose ignition timing is controlled by an ignition timing control device according to an embodiment of the present invention will be described. The engine 100 is provided with a plurality of cylinders. The ignition timing control apparatus according to the present embodiment is realized by a program executed by an engine ECU (Electronic Control Unit) 200, for example.

  Engine 100 is an internal combustion engine that burns an air-fuel mixture of air sucked from air cleaner 102 and fuel injected from injector 104 by igniting with an ignition plug 106 in a combustion chamber.

  When the air-fuel mixture burns, the piston 108 is pushed down by the combustion pressure, and the crankshaft 110 rotates. The combusted air-fuel mixture (exhaust gas) is purified by the three-way catalyst 112 and then discharged outside the vehicle. The amount of air taken into engine 100 is adjusted by throttle valve 114. An intake valve 116 and an exhaust valve 118 are provided at the top of the cylinder.

  Engine 100 is controlled by engine ECU 200. The engine ECU 200 includes a knock sensor 300, a water temperature sensor 302, a crank position sensor 306 provided facing the timing rotor 304, a throttle opening sensor 308, a vehicle speed sensor 310, an ignition switch 312, and an air flow meter. 314 is connected.

  Knock sensor 300 is provided in a cylinder block of engine 100. Knock sensor 300 is composed of a piezoelectric element. Knock sensor 300 generates a voltage due to vibration of engine 100. The magnitude of the voltage corresponds to the magnitude of the vibration. Knock sensor 300 transmits a signal representing a voltage to engine ECU 200.

  In the present embodiment, engine ECU 200 determines whether or not a knock has occurred based on a signal input from knock sensor 300. For example, if the magnitude (intensity) of vibration is greater than a threshold value, it is determined that knock has occurred. In addition, since it is sufficient to use a well-known technique as a method for determining whether or not knocking has occurred, further detailed description will not be repeated here. The knock detection means is not limited to a knock sensor that detects engine vibration, and may be a cylinder pressure center or the like.

  Water temperature sensor 302 detects the temperature of the cooling water in the water jacket of engine 100 and transmits a signal representing the detection result to engine ECU 200.

  The timing rotor 304 is provided on the crankshaft 110 and rotates together with the crankshaft 110. A plurality of protrusions are provided on the outer periphery of the timing rotor 304 at predetermined intervals. The crank position sensor 306 is provided to face the protrusion of the timing rotor 304. When the timing rotor 304 rotates, the air gap between the projection of the timing rotor 304 and the crank position sensor 306 changes, so that the magnetic flux passing through the coil portion of the crank position sensor 306 increases and decreases, and an electromotive force is generated in the coil portion. . Crank position sensor 306 transmits a signal representing the electromotive force to engine ECU 200. Based on the signal transmitted from crank position sensor 306, engine ECU 200 detects the crank angle and the rotational speed of crankshaft 110, that is, engine rotational speed NE.

  Throttle opening sensor 308 detects the throttle opening and transmits a signal representing the detection result to engine ECU 200. Vehicle speed sensor 310 detects the number of rotations of a wheel (not shown) and transmits a signal representing the detection result to engine ECU 200. Engine ECU 200 calculates the vehicle speed from the rotational speed of the wheel. Ignition switch 312 is turned on by the driver when engine 100 is started. Air flow meter 314 detects the amount of air taken into engine 100 and transmits a signal representing the detection result to engine ECU 200.

  In the present embodiment, engine ECU 200 calculates a load (load factor) of engine 100 based on engine speed NE and the amount of air taken into engine 100. In addition, since it is sufficient to use a well-known technique for the method for calculating the load, detailed description thereof will not be repeated here.

  Engine ECU 200 is operated by electric power supplied from auxiliary battery 320 as a power source. The engine ECU 200 performs arithmetic processing based on signals transmitted from the sensors and the ignition switch 312, maps and programs stored in a ROM (Read Only Memory) 202 and a SRAM (Static Random Access Memory) 204, and the engine 100 The devices are controlled so as to achieve a desired operation state.

  The function of engine ECU 200 will be described with reference to FIG. Note that the functions described below may be realized by software or hardware.

  The engine ECU 200 includes a setting unit 400, an ignition unit 402, a first retardation unit 404, a first change unit 406, an interruption unit 408, a determination unit 410, a second change unit 412, and a second retardation angle. A unit 414 and a correction unit 416.

  The setting unit 400 sets the basic ignition timing according to the engine speed NE and the load. For example, as shown in FIG. 3, the basic ignition timing is set according to a map having engine speed NE and load as parameters.

  An operation state (operation region) indicated by hatching in FIG. 3 indicates an operation state in which MBT is set to the basic ignition timing. MBT indicates the ignition timing at which the output torque of engine 100 is maximized. However, the maximum value of the output torque of engine 100 may change according to, for example, engine speed NE. The basic ignition timing may be set according to at least one of the engine speed NE and the load.

  In an operating state in which knocking cannot occur, that is, an operating state with a small load, MBT is set as the basic ignition timing. Therefore, when the operating state of engine 100 is a state where MBT is set to the basic ignition timing, knocking cannot occur.

  The ignition unit 402 controls the ignition timing of the spark plug 106 so as to ignite at the basic ignition timing. The ignition timing is controlled for each cylinder.

  As shown in FIG. 4, the first retarding unit 404 controls the ignition timing so as to retard from the basic ignition timing at a predetermined interval Nint. For example, the ignition timing is retarded every predetermined number of ignition cycles or every predetermined time. The ignition timing is retarded by the retard amount Qrtd. After the retard, the ignition timing is returned to the basic ignition timing. For example, after the ignition timing is retarded only for one ignition cycle, the ignition timing is returned to the basic ignition timing.

  Thereby, the ignition timing can be retarded intermittently regardless of whether or not knocking has occurred. Therefore, the temperature in the combustion chamber of the cylinder can be reduced. As a result, even after the ignition timing is returned to the basic ignition timing, knocking is less likely to occur during the period until the temperature in the combustion chamber rises. Further, since the ignition timing is retarded intermittently, the average value of the output torque can be increased compared to the case where the ignition timing is retarded continuously.

  Note that the alternate long and short dash line in FIG. 4 indicates the knock limit ignition timing when the ignition timing is operated at a constant ignition timing without performing intermittent retardation of the ignition timing. The knock limit ignition timing means the earliest ignition timing at which knock is considered not to occur. As shown in FIG. 4, in the present embodiment, when knocking occurs, the ignition timing is made earlier than the knock limit ignition timing when the ignition timing is retarded. Therefore, the output torque of engine 100 can be improved.

  Further, in the present embodiment, as shown in FIG. 5, the first retarding unit 404 controls the ignition timing so as to retard from the basic ignition timing in order in each cylinder at a predetermined interval Nint. To do. That is, the ignition timing is controlled so that each cylinder is retarded in the same order as the ignition order and the interval between the cylinders is “Nint”. FIG. 5 shows the retardation order when engine 100 is provided with four cylinders.

  Thus, the interval at which the ignition timing is retarded can be made substantially uniform throughout engine 100. Therefore, as indicated by the solid line in FIG. 6, the intervals at which the output torque of engine 100 fluctuates during one revolution of crankshaft 110 can be made substantially uniform. As a result, the vibration that can occur due to the retard of the ignition timing can be reduced. In each cylinder, the ignition timing may be retarded by an interval Nint. The broken line in FIG. 6 shows the output torque when the ignition timing is retarded simultaneously in each cylinder.

  The first change unit 406 determines at least one of the interval Nint for retarding the ignition timing and the retard amount Qrtd of the ignition timing according to at least one of the engine speed NE and the load of the engine 100. Change.

  For example, as shown in FIG. 7, an interval Nint for retarding the ignition timing is set according to a map having engine speed NE and load as parameters. The interval Nint is set smaller as the load increases. That is, the greater the load, the greater the frequency with which the ignition timing is retarded. Further, the interval Nint is set to be larger as the engine speed NE is larger. That is, the greater the engine speed NE, the lower the frequency at which the ignition timing is retarded.

  Further, as shown in FIG. 8, a retard amount Qrtd of a difference for retarding the ignition timing intermittently is set according to a map having the engine speed NE and the load as parameters. The retardation amount QRtd is set to be smaller as the load is larger. Further, the retard amount Qrtd is set to be larger as the engine speed NE is larger.

  Note that the method for setting the interval Nint and the retardation amount QRtd is not limited to these. 7 and 8, the operation state (operation region) indicated by hatching indicates an operation state in which MBT is set at the basic ignition timing, as in FIG.

  When the MBT is set to the basic ignition timing, the interrupting unit 408 interrupts the control of the ignition timing so as to be retarded intermittently at a predetermined interval Nint as shown in FIG. Thus, when MBT is set to the basic ignition timing, that is, in a state where knocking cannot occur, the ignition timing retardation can be immediately interrupted. Therefore, the frequency at which the ignition timing is retarded unnecessarily can be reduced. As a result, the frequency with which the output torque of engine 100 is unnecessarily reduced can be reduced.

  The broken line in FIG. 9 indicates the knock limit ignition timing when the ignition timing is retarded when knocking occurs without intermittent retarding of the ignition timing.

  Determination unit 410 determines whether or not knock has occurred in engine 100 based on a signal input from knock sensor 300. Further, the determination unit 410 determines the frequency of occurrence of knocking.

  The second changing unit 412 changes at least one of the interval Nint for retarding the ignition timing and the retard amount Qrtd for the ignition timing in accordance with the occurrence of knocking. For example, the interval Nint for retarding the ignition timing is set to be smaller as the frequency of occurrence of knocking increases. That is, the greater the frequency of knocking, the greater the frequency of retarding the ignition timing. In addition, the ignition timing retard amount QRtd is set to be larger as the frequency of occurrence of knocking increases. Note that the method for setting the interval Nint and the retardation amount QRtd is not limited to these.

  As shown in FIG. 10, the second retard portion 414 is the same retard amount Qrtd as when retarding the ignition timing from the basic ignition timing at a predetermined interval Nint when it is determined that knocking has occurred. Only the ignition timing is controlled to be retarded.

  After the retard, the ignition timing is returned to the basic ignition timing. For example, after the ignition timing is retarded only for one ignition cycle, the ignition timing is returned to the basic ignition timing. As a result, in addition to suppressing the decrease in output by intermittently retarding the ignition timing, it is possible to make it difficult to generate knock due to the cooling effect in the combustion chamber by temporarily retarding the ignition timing. When knocking occurs, the ignition timing may be retarded by an amount smaller or larger than the retard amount Qrtd.

  As shown in FIG. 11, the correction unit 416 corrects the basic ignition timing so that the ignition timing becomes slower as the frequency of occurrence of knocking increases. For example, when it is determined that knocking has occurred within a predetermined period, that is, when the frequency is equal to or greater than a threshold value, the basic ignition timing is delayed by a predetermined amount. Thereby, the ignition timing can be delayed as a whole. Therefore, it is possible to make knocking more difficult to occur.

  When the number of times that knocking has occurred within a predetermined period is less than the threshold value, the basic ignition timing is gradually advanced (accelerated) by a predetermined amount.

  A control structure of a program executed by engine ECU 200 will be described with reference to FIG. The program described below is repeatedly executed, for example, at a predetermined cycle.

  In step (hereinafter, step is abbreviated as S) 100, engine ECU 200 sets (calculates) basic ignition timing based on engine speed NE and engine 100 load.

  In S102, engine ECU 200 determines whether MBT is set to the basic ignition timing. This determination may use a map for the driving conditions, or may be estimated from an execution state such as knock control. If MBT is set to the basic ignition timing (YES in S102), the process proceeds to S112. If not (NO in S102), the process proceeds to S104.

  In S104, engine ECU 200 sets interval Nint for retarding the ignition timing and retard amount Qrtd for the ignition timing in accordance with engine speed NE, engine 100 load, and the frequency of occurrence of knocking.

  In S106, engine ECU 200 determines whether or not it is time to execute intermittent retardation at interval Nint. For example, when it is time to execute intermittent retardation at interval Nint (YES in S106), the process proceeds to S108. If not (NO in S106), the process proceeds to S110.

  In S108, engine ECU 200 controls the ignition timing so as to be retarded from the basic ignition timing. In S110, engine ECU 200 controls the ignition timing to ignite at the basic ignition timing.

  In S112, engine ECU 200 interrupts the control of the ignition timing so as to be retarded intermittently at interval Nint.

  In S120, engine ECU 200 determines whether or not a knock has occurred based on a signal input from knock sensor 300. If a knock has occurred (YES in S120), the process proceeds to S122. If not (NO in S120), the process proceeds to 124.

  In S122, engine ECU 200 controls the ignition timing so as to be retarded from the basic ignition timing. In S124, engine ECU 200 controls the ignition timing to ignite at the basic ignition timing.

  In S130, engine ECU 200 determines whether or not the frequency of occurrence of knocking is greater than a threshold value. If the frequency of occurrence of knocking is greater than the threshold value (YES at S130), the process proceeds to S132. If not (NO in S130), the process proceeds to S134.

  In S132, engine ECU 200 delays the basic ignition timing by a predetermined amount. In S134, engine ECU 200 advances (accelerates) the basic ignition timing by a predetermined amount.

  The operation of the ignition timing control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  During the operation of the engine 100, the basic ignition timing is set based on the engine speed NE and the load of the engine 100 (S100). If MBT is not set to the basic ignition timing (NO in S102), the interval Nint for retarding the ignition timing and the delay of the ignition timing according to the engine speed NE, the load on engine 100, and the frequency of occurrence of knocking. The angular amount QRtd is set (S104).

  If it is not time to execute the intermittent retardation at the interval Nint (NO in S106), the ignition timing is controlled to ignite at the basic ignition timing (S110). If it is time to execute intermittent retardation at the interval Nint (YES in S106), the ignition timing is controlled so as to retard from the basic ignition timing (S108).

  On the other hand, when MBT is set to the basic ignition timing (YES in S102), the operating state of engine 100 is a state in which knocking cannot occur. Therefore, it is not necessary to retard the ignition timing. Therefore, the ignition timing control is interrupted so as to be intermittently retarded at the interval Nint (S112).

  When knocking occurs (YES in S120), the ignition timing is controlled so as to retard from the basic ignition timing in addition to the intermittent retardation at the interval Nint, that is, at an interval shorter than the interval Nint ( S122). Thereby, it is possible to make it difficult for knocking to occur. If knocking has not occurred (NO in S120), the ignition timing is controlled to ignite at the basic ignition timing (S124).

  If the frequency of occurrence of knocking is greater than the threshold value (YES at S130), the basic ignition timing is delayed by a predetermined amount in order to make knocking more difficult to occur (S132). If the frequency of occurrence of knocking is equal to or less than the threshold value (NO in S130), the basic ignition timing is advanced by a predetermined amount (S134).

  As described above, according to the ignition timing control apparatus according to the present embodiment, the basic ignition timing is set according to the engine speed NE and the load. The ignition timing is controlled so as to be retarded from the basic ignition timing at a predetermined interval Nint. Thereby, the ignition timing can be retarded intermittently regardless of whether or not knocking has occurred. Therefore, the temperature in the combustion chamber of the cylinder can be reduced. As a result, even after the ignition timing is returned to the basic ignition timing, knocking is less likely to occur during the period until the temperature in the combustion chamber rises. Further, since the ignition timing is retarded intermittently, the average value of the output torque can be increased compared to the case where the ignition timing is retarded continuously. Further, at least one of the interval Nint for retarding the ignition timing and the retard amount Qrtd of the ignition timing is changed in accordance with at least one of the engine speed NE and the engine load. Thereby, in a state where knocking is likely to occur, the interval Nint for retarding the ignition timing can be reduced or the amount Qrtd for retarding can be increased to make it difficult for knocking to occur. Further, when the MBT is set to the basic ignition timing, the control of the ignition timing is interrupted so as to intermittently retard at the interval Nint. As a result, when MBT is set to the basic ignition timing, that is, in a state where knocking cannot occur, the retardation of the ignition timing can be interrupted immediately. Therefore, the frequency at which the ignition timing is retarded unnecessarily can be reduced. As a result, the frequency with which the output torque of the engine is unnecessarily reduced can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram which shows an engine. It is a functional block diagram of engine ECU. It is a figure which shows the map which defined the basic ignition timing. It is a figure which shows the space | interval Nint which retards intermittently from basic ignition timing, and retard amount Qtrd. It is a figure which shows the ignition timing retarded in order in each cylinder. It is a figure which shows the output torque of an engine. It is a figure which shows the map which defined the space | interval Nint which retards ignition timing. It is a figure which shows the map which defined retardation amount QRtd. It is a figure which shows the ignition timing at the time of interrupting the intermittent retardation from basic ignition timing. It is a figure which shows the ignition timing when a knock generate | occur | produces. It is a figure which shows the basic ignition timing in case the frequency which knocked is large. It is a flowchart which shows the control structure of the program which engine ECU performs.

Explanation of symbols

  100 engine, 102 air cleaner, 104 injector, 106 spark plug, 108 piston, 110 crankshaft, 112 three-way catalyst, 114 throttle valve, 116 intake valve, 118 exhaust valve, 200 engine ECU, 202 ROM, 204 SRAM, 300 knock sensor , 302 Water temperature sensor, 304 Timing rotor, 306 Crank position sensor, 308 Throttle opening sensor, 310 Vehicle speed sensor, 312 Ignition switch, 314 Air flow meter, 320 Auxiliary battery, 400 Setting unit, 402 Ignition unit, 404 First retardation Part, 406 first change part, 408 interruption part, 410 determination part, 412 second change part, 414 correction part, 416 second retardation part.

Claims (8)

An ignition timing control device for an internal combustion engine,
Means for setting a basic ignition timing according to at least one of the output shaft speed and the load of the internal combustion engine;
Means for controlling the ignition timing to ignite at the basic ignition timing;
Retarding means for controlling the ignition timing so as to retard from the basic ignition timing at a predetermined interval;
Means for changing at least one of an interval for retarding the ignition timing and an amount for retarding the ignition timing according to at least one of the output shaft speed and the load of the internal combustion engine;
When the ignition timing determined to maximize the output torque of the internal combustion engine is set to the basic ignition timing, the control for igniting the ignition timing so as to be retarded at the predetermined interval is interrupted. And an ignition timing control device for an internal combustion engine. Means for determining whether a knock has occurred;
2. The internal combustion engine according to claim 1, further comprising changing means for changing at least one of an interval for retarding the ignition timing and an amount for retarding the ignition timing according to a knock generation state. Ignition timing control device.   The ignition timing control device for an internal combustion engine according to claim 2, wherein the changing means includes means for reducing the interval at which the ignition timing is retarded as the frequency of occurrence of knocking increases.   The ignition timing control device for an internal combustion engine according to claim 2, wherein the changing means includes means for increasing the amount by which the ignition timing is retarded as the frequency of occurrence of knocking increases.   The ignition timing control device for an internal combustion engine according to any one of claims 2 to 4, further comprising means for correcting the basic ignition timing so that the ignition timing is delayed as the frequency of occurrence of knocking increases.   The apparatus further comprises means for retarding the ignition timing by the same amount as retarding the ignition timing from the basic ignition timing at the predetermined interval when knocking occurs. The ignition timing control device for an internal combustion engine according to any one of?   The apparatus further comprises means for retarding the ignition timing by an amount different from that when retarding the ignition timing from the basic ignition timing at the predetermined interval when knocking occurs. The ignition timing control device for an internal combustion engine according to any one of? The internal combustion engine is provided with a plurality of cylinders,
The retarding means includes means for controlling an ignition timing so as to retard from the basic ignition timing at the predetermined interval and in order in each cylinder. An ignition timing control device for an internal combustion engine as described.

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