JP2001234801A - Knocking control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Problem] To reduce the ignition timing delay amount when knocking occurs while avoiding knocking while ensuring operability, and minimize exhaust temperature rise, fuel consumption deterioration and output decrease due to ignition timing delay. Provided is an engine knocking control device which can be minimized. Kind Code: A1 A knocking control device includes knocking determination means for determining the presence or absence of knocking based on a knock detection signal from a knock sensor, and ignition timing control means for controlling ignition timing based on a determination result.
And variable valve control means 501 capable of variably controlling the valve timing of the engine. When the result of the determination is determined to be knocking and the ignition timing is retarded, the ignition timing is retarded according to the retard amount. Thus, the opening / closing timing of the intake valve is retarded by the variable valve control means 501.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a knocking control device for an internal combustion engine, and more particularly to a knocking control device for suppressing the occurrence of knocking in an internal combustion engine (gasoline engine) for a vehicle such as an automobile.

[0002]

2. Description of the Related Art As means for improving the fuel efficiency of an internal combustion engine for a vehicle such as an automobile (hereinafter sometimes abbreviated as an engine),
A higher compression ratio of the engine is being considered. However, increasing the compression ratio of the engine causes a reduction in the knocking limit. For this reason, in the high compression ratio engine, occurrence of knocking particularly in a high load region is a problem.

[0003] As is well known, knocking in a gasoline engine causes a large pressure imbalance in the combustion chamber due to the self-ignition of the end of the flame propagation of the mixture in the combustion chamber of the engine. Is a phenomenon that vibrates the combustion chamber wall and is transmitted to the engine block.

[0004] Knocking causes loss of energy generated by the engine (output reduction), impacts on various parts of the engine, and further lowers fuel efficiency. Therefore, it is desirable to avoid knocking as much as possible. In addition to the detection, it is necessary to control the engine to avoid the knocking occurrence state when knocking occurs.

[0005] From this viewpoint, conventionally, in the case of knocking, in an automobile engine, the ignition timing is controlled based on the engine speed and the load, which are parameters of the engine state. The ignition timing is advanced to the knocking limit to suppress occurrence of knocking.

In an engine in which such ignition timing control is performed, knocking vibration is detected by knocking detection means, and whether knocking has occurred in the engine is determined by knocking determination means, and it is determined that knocking has occurred in the engine. In such a case, for example, it is known that the ignition timing is retarded, and then, when it is determined that knocking has not occurred, the ignition timing is retarded such that the ignition timing gradually approaches the optimal ignition timing. (JP-A-5-26778, etc.).

Japanese Patent Application Laid-Open Nos. 59-93939 and 8-33296 have a variable valve timing mechanism for varying the opening / closing timing of an intake valve of an engine, and close the intake valve when knocking occurs. A knocking control technique for avoiding the occurrence of knocking by retarding the valve timing is disclosed.

According to this, the actual compression stroke is shortened by delaying the closing timing of the intake valve and opening the intake valve until the beginning of the cylinder compression stroke after the bottom dead center of the intake stroke. Reduction of compression ratio and filling efficiency is performed.
When the actual compression ratio decreases, the knocking limit of the ignition timing is offset to the advance side, so that knocking can be avoided without retarding the ignition timing.

Japanese Patent Application Laid-Open No. 11-036906 discloses that the occurrence frequency of knocking of an engine is monitored, and when the occurrence frequency of knocking becomes high, the ignition timing necessary for avoiding knocking is calculated, and the ignition timing is delayed and the intake valve is simultaneously opened. A technique is disclosed for delaying the valve closing timing to avoid knocking.

[0010]

However, in avoiding knocking by retarding the ignition timing, in the case of an engine having a high compression ratio, the ignition characteristic sharply increases as the compression pressure increases, so that the average effective pressure is sacrificed. As a result, there is a problem that fuel economy is inevitably deteriorated, and at high load and high speed, the exhaust gas temperature rises and adversely affects the durability of the engine.

On the other hand, in the knocking avoidance due to the delay of the closing timing of the intake valve, the above-described problem due to the ignition timing retardation does not occur, but the closing timing of the intake valve is retarded. This has a direct effect on the reduction of the engine output, which is undesirable in terms of driving performance, and it is desirable to avoid it as much as possible. In addition, the retard of the closing timing of the intake valve controls the amount of intake air, and the intake air amount control has low sensitivity to the output of the engine. In this case, it is considered that the engine operability after the occurrence of knocking is degraded, and it is desired that the delay of the closing timing of the intake valve be avoided as much as possible.

Further, the occurrence frequency of knocking of the engine is monitored, and when the occurrence frequency of knocking becomes high, the ignition timing necessary for avoiding knocking is calculated, and the ignition timing is delayed and at the same time, the closing timing of the intake valve is retarded. In order to avoid knocking, the closing timing of the intake valve is positively retarded along with the ignition timing in accordance with the frequency of knocking. It becomes a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to control the ignition timing and the charging efficiency (known as variable valve control or throttle control) when knocking occurs. ) Is used in an appropriate combination to ensure that the engine output and engine operability are as low as possible, while reducing the deterioration of fuel efficiency and the adverse effect on engine durability and appropriately avoiding the occurrence of knocking. An object of the present invention is to provide a knocking control device for an internal combustion engine.

[0014]

In order to achieve the above object,
A knocking control device for an internal combustion engine according to the present invention includes: a knocking detection unit configured to detect knocking vibration generated in the internal combustion engine; a knocking determination unit configured to determine the presence or absence of knocking based on a knocking detection signal output from the knocking detection unit; In a knocking control apparatus for an internal combustion engine, comprising: an ignition timing control means for controlling an ignition timing of an engine; and a charging efficiency varying means capable of changing a charging efficiency of the internal combustion engine, wherein the ignition timing control means comprises: In response to the determination result of the means, if the determination result indicates that there is knocking, the ignition timing control means retards the ignition timing of the internal combustion engine, and the charging efficiency variable means controls the internal combustion engine by the ignition timing control means. It is characterized in that the charging efficiency of the internal combustion engine is reduced according to the retardation of the ignition timing.

According to this configuration, when knocking occurs in the internal combustion engine and knocking is determined by knocking determination means and the ignition timing is retarded by the ignition timing control means, the charging efficiency is determined according to the ignition timing delay. The filling efficiency is reduced by the variable means. As a result, it is possible to avoid knocking by reducing deterioration in fuel efficiency and adversely affecting engine durability while ensuring engine output and engine operability as much as possible. In a specific aspect of the knocking control device for an internal combustion engine according to the present invention, the charging efficiency variable means is a variable valve control means for delaying the opening / closing timing of an intake valve of the internal combustion engine by an actuator.

According to this configuration, when knocking occurs in the internal combustion engine and knocking is determined by the knocking determination means and the ignition timing is retarded by the ignition timing control means, the variable operation is performed according to the ignition timing delay. The opening and closing timing of the intake valve is retarded by the valve control means.
As a result, the filling efficiency of the internal combustion engine is reduced, the engine output and the engine operability are secured as much as possible,
Knocking can be avoided by reducing adverse effects on engine durability.

In a specific aspect of the knocking control device for an internal combustion engine according to the present invention, when the knocking determination means determines that knocking is present and the ignition timing control means delays the ignition timing by a predetermined value or more, The valve closing timing of the intake valve is retarded by the variable valve control means.

According to this configuration, when knocking occurs in the internal combustion engine, knocking is determined by the knocking determination means, and the ignition timing retarding amount by the ignition timing control means becomes equal to or greater than a predetermined value, the variable valve control means is first turned on. Thus, the opening / closing timing of the intake valve is retarded. As a result, it is possible to reduce the charging efficiency of the internal combustion engine and to avoid knocking by reducing deterioration in fuel efficiency and adversely affecting engine durability while ensuring engine output and engine operability as much as possible. .

Further, in a specific mode of the knocking control device for an internal combustion engine according to the present invention, the retard release of the closing timing of the intake valve is gradually released from the time when the ignition timing retard amount is reduced to a predetermined value or less. It is characterized by performing. According to such a configuration, the intake valve controlled by the knocking control is:
By gradually returning to the basic valve timing from the point in time when the ignition timing retard amount is reduced to a predetermined value or less, rebound to drivability can be minimized and knocking can be avoided.

In a specific aspect of the knocking control apparatus for an internal combustion engine according to the present invention, during knocking control, intake valve control by the variable valve control means according to the operating state of the internal combustion engine is prohibited, and knocking is avoided. The intake valve retard control is performed with priority.

According to this configuration, the variable valve control calculates the target valve timing based on the operating state and the like to control the valve timing. However, when the knocking control is performed, this control is prohibited. The intake valve retard control for avoiding knocking is preferentially performed, so that occurrence of knocking can be avoided. Further, in a specific aspect of the knocking control device for an internal combustion engine according to the present invention, the charging efficiency varying means is a throttle control means for reducing a throttle opening of the internal combustion engine by an actuator.

With this configuration, when knocking occurs in the internal combustion engine, knocking is determined by knocking determination means, and ignition timing is retarded by ignition timing control means, throttle control is performed in accordance with the ignition timing delay. The throttle opening is reduced by the means. As a result, it is possible to reduce the charging efficiency of the internal combustion engine and to avoid knocking by reducing deterioration in fuel efficiency and adversely affecting engine durability while ensuring engine output and engine operability as much as possible. .

In a specific embodiment of the knocking control device for an internal combustion engine according to the present invention, when the knocking determination means determines that knocking is present and the ignition timing control means delays the ignition timing by a predetermined value or more, The throttle valve is closed by the throttle control means.

According to this configuration, knocking occurs in the internal combustion engine, knocking is determined by the knocking determination means, and when the ignition timing retard amount by the ignition timing control means becomes equal to or greater than a predetermined value, the throttle control means first controls the throttle. Closing the valve is performed. As a result, it is possible to reduce the charging efficiency of the internal combustion engine and to avoid knocking by reducing deterioration in fuel efficiency and adversely affecting engine durability while ensuring engine output and engine operability as much as possible. .

In a specific embodiment of the knocking control device for an internal combustion engine according to the present invention, the closing of the throttle valve is gradually released from the time when the ignition timing retard amount is reduced to a predetermined value or less. I have. According to such a configuration, the throttle opening controlled by the knocking control is gradually returned to the basic throttle opening from the time when the ignition timing retard amount is reduced to a predetermined value or less, thereby minimizing rebound to drivability. Thus, occurrence of knocking can be avoided.

In a specific embodiment of the knocking control apparatus for an internal combustion engine according to the present invention, during the knocking control, the throttle control by the throttle control means in accordance with the operating state of the internal combustion engine is prohibited, and the knocking control is performed. The throttle closing control is preferentially performed.

According to this configuration, the throttle control
The throttle opening is controlled by calculating the target throttle opening based on the operating conditions.If knocking control is being performed, this control is prohibited, and throttle closing control is given priority to avoid knocking. And knocking can be avoided.

[0028]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an internal combustion engine knocking control apparatus according to an embodiment of the present invention. FIG. 1 shows an overall configuration of an engine system including a knocking control device according to the present embodiment.

An air cleaner 101, an air flow sensor 103, a throttle valve device 121, a collector 105, an intake pipe 106 are provided at an intake port 100A of the engine 100.
Are connected in order. The air taken in by the engine 100 is taken in from an inlet 102 of an air cleaner 101, passes through an air flow sensor 103, passes through a throttle valve device 121 provided with a throttle valve 104 for controlling the amount of intake air, and enters a collector 105. Collector 105
Is distributed to each intake pipe 106 connected to each cylinder (cylinder) 107 of the engine 100 and guided to the inside 107 of the cylinder.

A throttle motor 120 is drivingly connected to the throttle valve 104.
, The throttle valve 104 is electrically operated to open and close. On the other hand, fuels such as gasoline
The fuel is pressurized from a fuel tank 108 by a low-pressure fuel pump 109, adjusted to a predetermined pressure by a pressure regulator 111, and supplied to a fuel injector 110. The fuel injector 110 is provided at the intake port 100A of each cylinder, and the fuel injected from the fuel injector 110 enters the cylinder 107 together with the intake air, and the ignition plug 113 is driven by the discharge voltage raised by the ignition coil 112. It is ignited by sparks.

The air flow sensor 103 measures an intake air flow rate and inputs a signal representing the intake air flow rate to a control unit (engine control unit) 114. A throttle opening sensor (not shown) is attached to the throttle valve device 121. The throttle opening sensor detects the opening of the throttle valve 104 and inputs a signal representing the throttle opening to the control unit 114. . An accelerator sensor (not shown) is provided in the throttle valve device 121.
The accelerator sensor detects the amount of operation of the accelerator pedal 122 by the driver, and outputs a signal indicating the amount of operation of the accelerator pedal to the control unit 11.
Enter 4

A crank angle sensor 115 is attached to the crank chamber of the engine 100. The crank angle sensor 115 detects the rotation angle of the crank shaft 116, that is, the crank angle, and inputs a signal representing the crank angle to the control unit 114. The control unit 114 controls the fuel injection amount, timing, and ignition timing based on the input signal.

An intake valve 123 for opening and closing the intake port 100A of the engine 100 is driven by a cam shaft 119. The camshaft 119 includes a well-known variable valve control mechanism 1.
18 are connected. The variable valve control mechanism 118 controls the variable operation using the lubricating oil of the engine 100 as hydraulic oil based on cam angle signals from the crank angle sensor 115 and a cam angle sensor 314 (see FIG. 2) for detecting the rotation angle of the cam shaft. Driven by the actuator 121 (see FIG. 2), the relative angle of the camshaft 119 to the crankshaft 116 is changed.

In the vicinity of the center of the cylinder block of the engine 100, a knock sensor 1 is provided as knocking detecting means.
17 are attached. This knock sensor 117
Is constituted by a piezoelectric element, for example, and the engine 100
Is output to the control unit 114 in accordance with the knocking vibration level.

FIG. 2 shows a functional configuration of the knocking control device 300 provided in the engine control device 114 of FIG. 1 according to one embodiment of the present invention. Knocking control device 300 includes a knocking determination unit 303, an ignition timing control unit 304, and a variable valve control unit 50 that is a charging efficiency variable unit that can change the charging efficiency of the internal combustion engine.
And 1.

The knocking control device 300 sends the engine status information (for example, engine speed, intake air amount, engine water temperature, vehicle speed, etc.) to the I / O port 321 through the crank angle sensor 115, the air flow sensor 103, and the water temperature sensor. 311 and the like, and as knocking sensor 11 as state information necessary for knocking control and variable valve control.
7 and the output signal of the cam angle sensor 314 are I /
Input to the O port 321. The analog input (air flow sensor signal, water temperature sensor signal, knocking sensor signal) is converted from analog to digital by the A / D converter 320, and then input to the knocking control device 300 from the I / O port 321.

The knocking control device 300 calculates a fuel supply amount, an ignition timing, and the like based on a signal from each sensor, and outputs a control signal to the injector 110 and the ignition coil 112 via the drive circuit 322. The knocking signal is fetched by the knocking control device 300 and sampled by the A / D converter 320 in synchronization with the clock cycle of the knocking control device 300.
The signal of knocking sensor 117 is converted into a digital signal by knocking determination means 303, which is input to knocking determination means 303, and knocking determination means 303 determines the presence or absence of knocking. The knocking determination result by knocking determination means 303 is input to ignition timing control means 304, and ignition timing control means 304 performs ignition timing correction control based on the knocking determination result.

Next, the ignition timing correction control by the ignition timing control means 304 will be described with reference to FIG. When the knocking determination means 303 determines that knocking has occurred in the engine 100, the ignition timing control means 304 corrects the ignition timing to the retard side. FIG.
Is a flowchart of the ignition timing control at this time. The operation of this flowchart is performed at regular time intervals, for example, 1
It is repeated every 0 msec.

First, the RAM in the ignition timing control means 304
The engine speed N and the intake air amount Q are read from a predetermined register set in step (1) (step 401). next,
Calculate the intake air amount Q / N per unit rotation speed, further obtain the fuel injection time Ti from Q / N, and calculate the basic ignition timing θbase from the basic ignition timing map stored in the ROM for fuel supply. (Step 402).

Next, the result of the determination is input from the knocking determination means 303 to determine whether knocking has occurred (step 403). If knocking has occurred, a predetermined retard amount Δθret is subtracted from the current ignition timing advance amount θadv (step 404). The ignition timing is retarded by this subtraction. On the other hand, if there is no knocking,
A predetermined advance amount Δadv is added to the current ignition timing advance amount θadv to update the ignition timing advance amount θadv (step 40).
5). Next, the ignition timing advance θign which is updated as described above is added to the basic ignition timing θbase to calculate the ignition timing θign of the control target (step 406).

Next, the maximum advance value θres is obtained according to the engine speed N and the intake air amount Q / N (step 4).
07). The maximum advance value θres is determined by R
It is determined by reading from the maximum advance value map stored in the OM. Next, it is determined whether or not the ignition timing θign has exceeded the maximum advance value θres (step 40).
8) If the ignition timing θign exceeds the maximum advance value θres, it is an over-advance angle, so the maximum advance value θres is changed to the ignition timing θi.
gn (step 409).

Finally, as described above, the ignition timing θign
Is set, output information to the ignition coil 112 is set (step 410). Thus, by detecting knocking and controlling the ignition timing, it is possible to avoid knocking of the engine. Next, the variable valve control by the variable valve control means 501 will be described.

The variable valve control means 501 inputs the engine coolant temperature and the vehicle speed in the same manner as described above, and the knocking determination section 303 determines whether knocking has occurred or not.
An engine ignition timing adjustment amount (such as a retard amount), which is a calculation result of the ignition timing control means 304, is input, and an optimal valve timing is calculated from the input information, and the variable valve actuator 121 (for example, a solenoid or the like) is calculated. The output signal is sent to the variable valve actuator 121 via the drive circuit 322.
To control the valve timing. Next, the operation of the knocking control device according to the present invention will be described below according to an embodiment. In the present embodiment,
A variable valve mechanism in which the exhaust valve has a fixed phase and only the intake valve has a variable phase is taken as an example.

FIG. 4 shows a flowchart of a variable valve control operation using the ignition timing correction amount. First, according to the processing flow shown in FIG. 3, knocking determination means 303 and ignition timing control means 304 perform knocking determination processing and ignition timing correction control (step 121).

Next, an ignition timing correction amount (ignition timing retardation amount = ignition timing retard amount) is inputted from the ignition timing control means 304, and the ignition timing retard amount is set to a predetermined value (variable valve control start slice). It is determined whether the level is equal to or higher than the level (Son) (step 122). Even if knocking occurs, if the ignition timing is less than the predetermined value Son, the control is terminated without performing the variable valve control. Thus, when the ignition timing retard amount is small, the intake valve retard control is not performed, and normal operability can be ensured.

On the other hand, if the ignition timing retard amount is equal to or greater than the predetermined value Son, it is determined whether or not the intake valve opening / closing timing control has already been performed by the variable valve control means 501 (step 123). If the intake valve opening / closing timing control has already been performed, the intake valve opening / closing timing control is prohibited (step 124). Depending on the operating state, even when knocking occurs, the intake valve may be advanced to improve drivability (for example, variable valve control for requesting torque). In such a case, , Prohibiting the advance of the intake valve.

Next, in order to avoid knocking, the opening and closing timing of the intake valve is retarded (step 125) to avoid knocking. The setting of the retard amount will be described later. Next, an ignition timing correction amount (ignition timing retardation amount = ignition timing retard amount) is input from the ignition timing control means 304, and the ignition timing retard amount is set to a predetermined value (variable valve control release slice level Soff). It is determined whether or not the above is true (step 126). However, regarding the ignition timing retard amount, Son>
Soff.

If the ignition timing retard amount is larger than the predetermined value Soff, the intake valve retard control is continued, while if the ignition timing retard amount is reduced below the predetermined value Soff, the intake valve retard control is performed. It is released and advanced to the basic intake valve operating angle (step 127). Here, the advance of the opening / closing timing of the intake valve (the release of the retard of the closing timing of the intake valve) is gradually performed from the time when the ignition timing retard amount becomes less than the predetermined value Soff in consideration of drivability. desirable.

The predetermined value Soff is determined when the ignition timing returns to the basic ignition timing, that is, the predetermined value Soff.
By setting ff to 0, the intake to the engine is stabilized, and the drivability is improved. However, the ignition timing is retarded for a long time, which is disadvantageous for the exhaust gas temperature, fuel consumption, and output. Details will be described later.

Next, a method for setting the intake valve retard amount for avoiding knocking in the present embodiment will be described. However, as described above, it is known that knocking is prevented by retarding the intake valve, so that the knocking will be briefly described with reference to FIGS. 5 and 6 show changes in the intake stroke due to rotation of the intake valve camshaft. Usually, the valve timing is changed from the basic valve timing according to the engine speed. FIG. 5 shows a valve timing and a timing area when the valve is advanced or retarded from the basic valve timing. FIG. 6 is a valve opening / closing diagram at the time of advance and at the time of retard. Here, TDC represents top dead center, and BDC represents bottom dead center. When the intake valve is advanced, the intake valve is opened at IVO2, and the intake valve is closed at IVC2. On the other hand, when the intake valve is retarded, the intake valve is opened at IVO1, and the intake valve is closed at IVC1. As can be seen from the above, as the intake valve is retarded, the intake valve is open even during the compression stroke, and the actual compression ratio decreases. When the actual compression ratio decreases, the knocking region for the ignition timing of the engine moves to the advance side, so that knocking can be avoided.

However, when attempting to avoid knocking by controlling the intake air amount, the present embodiment has a lower sensitivity to knocking than does knocking due to retarded ignition timing. It is better to rely on the ignition timing for the initial knocking. Therefore, it is desirable that the amount of retardation of the intake valve be set in consideration of the amount of retardation of ignition timing such that the exhaust gas temperature, output, and fuel consumption are not significantly sacrificed, and the above-described sensitivity of the air amount to knocking. . Next, a knocking determination result and an operation image of ignition timing control and variable valve control according to the present embodiment will be described with reference to FIGS.

As shown in FIGS. 7 (a) to 7 (d), when the ignition timing retard amount does not exceed the variable valve control start slice level Son even if it is determined that knocking has occurred in the knocking determination. The knocking is avoided only by the ignition timing retard, without performing the variable valve control (the intake valve retard).

On the other hand, when it is determined by knocking that knocking has occurred and the ignition timing retard amount exceeds the variable valve control start slice level Son, an intake valve retard request is set, and the variable valve control means 501 By operating the variable valve actuator 121, the opening / closing timing of the intake valve 123 is retarded. As a result, occurrence of knocking can be avoided.

If the ignition timing retard amount is reduced to the variable valve control release slice level Soff or less, the intake valve retard request is released, and the opening / closing timing of the intake valve 123 becomes the basic operating angle (basic valve timing). Thus, the opening / closing timing of the intake valve 123 is gradually advanced by the control of the variable valve control means 501.

By performing the above control, the time during which the ignition timing is retarded is shortened, and the amount of retardation due to the ignition timing is greatly suppressed, as compared with the case where the variable valve control according to the present invention is not provided. Can be. Also, by gradually returning the intake valve retard, it is possible to minimize rebound to drivability.

FIG. 8 shows a variable valve control release slice level S.
off indicates the case where the ignition timing returns to the basic ignition timing, that is, the case where the predetermined value is set to 0. The operation procedure is as described in FIG. In this control characteristic, the intake valve 123 is retarded until the ignition timing returns to the basic ignition timing, so that the intake characteristic of the engine is stabilized and the operability is improved. However, since the ignition timing retard time becomes longer, the exhaust gas temperature, the output, and the fuel efficiency are disadvantageous compared to the case of the control characteristics shown in FIG. However, as compared with the case where the control according to the present invention is not performed, the time during which the ignition timing is retarded becomes shorter, and the effect that the retard amount due to the ignition timing can be largely suppressed can be obtained. As described above, by using the knocking control according to the present embodiment, it is possible to reduce the ignition timing retard amount and the ignition timing retard time while avoiding knocking.

FIG. 9 shows another embodiment of the knocking control device according to the present invention. In FIG. 9,
Parts corresponding to those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and the description thereof will be omitted. In this embodiment,
As a charging efficiency variable means capable of changing the charging efficiency of the internal combustion engine, a knocking control device 900 is provided with a throttle control means 901 instead of the variable valve control means 501.

The basic input information, the fuel injection control, the ignition control, and the like of the knocking control device 900 are the same as those of the knocking control device 300 described with reference to FIG. 2, and are as described above. The difference is that the accelerator opening sensor 902 and the throttle opening sensor 903 are input as analog information as information necessary for throttle control. The processing after the input is the same as that of the knock sensor 117 described with reference to FIG. The knocking determination means 303 is also as described above.

The throttle control means 901 inputs the engine water temperature and the vehicle speed in the same manner as described above, and the knocking determination section 303 determines whether knocking has occurred or not, and the engine ignition timing which is the calculation result of the ignition timing control means 304. Enter the adjustment amount (eg, retard amount). The throttle control means 901 calculates an optimum throttle opening from the input information, outputs an output signal of the throttle motor 120 for opening and closing the throttle valve 104 to the throttle motor 120 via the drive circuit 322, and outputs the throttle opening. Control the degree. With the above control, the throttle opening can be controlled by freely driving the throttle motor 120 according to the operating state.

FIG. 10 shows a flowchart of a throttle control operation using the ignition timing correction amount. First,
According to the processing flow shown in FIG. 3, knocking determination means 303 and ignition timing control means 304 perform knocking determination processing and ignition timing correction control (step 22).
1).

Next, an ignition timing correction amount (ignition timing retardation amount = ignition timing retard amount) is inputted from the ignition timing control means 304, and the ignition timing retard amount is set to a predetermined value (slot closing control start slice level). (Son ') or not (Step 222).

Even if knocking occurs, if the ignition timing is less than the predetermined value Son ', the throttle control is not performed.
The control ends as it is. Thus, when the ignition timing retard amount is small, the throttle closing control is not performed, and normal operability can be ensured.

On the other hand, if the ignition timing retard amount is equal to or greater than the predetermined value Son ', the throttle control means 901 determines whether or not normal throttle control has already been performed (step 223). If normal throttle control has already been performed, normal throttle control is prohibited (step 224). Depending on the operation state, even if knocking occurs, the throttle valve 104 is used to improve drivability (for example, throttle control for requesting torque).
May be opened. In such a case, opening the throttle valve 104 is prohibited.

Next, in order to avoid knocking, the throttle valve 104 is closed by the throttle motor 120 (step 225) to avoid knocking. The setting of the closing amount of the throttle valve 104 will be described later. Next, an ignition timing correction amount (ignition timing retard amount = ignition timing retard amount) is input from the ignition timing control means 304, and the ignition timing retard amount is set to a predetermined value (throttle closing control release slice level Soff '). It is determined whether or not the above is the case (step 226). However, also in this case, Son '>Soff' regarding the ignition timing retard amount.

If the ignition timing retard amount is larger than the predetermined value Soff ', the throttle closing control is continued, and
If the ignition timing value angle amount is reduced below the predetermined value Soff ',
The throttle closing request is released, and the throttle valve 104 is opened by the throttle motor 120 so that the basic throttle opening is obtained (step 227). Here, it is desirable that the opening of the throttle valve 104 (release of the closing of the throttle valve) be gradually performed in consideration of operability from the time when the ignition timing retard amount is reduced to less than the predetermined value Soff ′.

The predetermined value Soff ′ here is determined when the ignition timing returns to the basic ignition timing, that is, the predetermined value Soff ′.
By setting off 'to 0, the intake to the engine is stabilized, and the drivability is improved. However, the ignition timing is retarded for a long time, which is disadvantageous for the exhaust gas temperature, fuel consumption, and output. Details will be described later.

Next, a method of setting the throttle closing amount for avoiding knocking in the present embodiment will be described. The method of lowering the charging efficiency by controlling the throttle opening degree is because the air amount does not change suddenly with respect to the engine,
The efficiency is inferior to the variable valve control described above. The closing amount of the throttle valve is desirably set in consideration of a knocking avoidance region due to ignition timing retard, a charging efficiency that is reduced by closing the throttle, and operability. Next, the knocking determination result, the ignition timing retard amount, and the operation image of the throttle control in this embodiment are shown in FIG.
This will be described with reference to FIG.

In FIG. 11, the knocking determination
Even if it is determined that knocking has occurred, if the ignition timing retard amount does not exceed the throttle closing control start slice level Son ', throttle closing control is not performed, and knocking is avoided only by ignition timing retarding. On the other hand, when it is determined by the knocking determination that knocking has occurred and the ignition timing has exceeded the throttle closing control start slice level Son ',
A throttle closing control request is set, and the throttle motor 120 is operated by the throttle control means 901.
Close the throttle valve 104. As a result, the engine 10
Since the amount of intake air to zero is reduced and the charging efficiency is reduced, occurrence of knocking can be avoided.

When the ignition timing retard amount is reduced to the throttle closing control start slice level Soff ′ or less, the throttle closing request is canceled and the throttle valve 104 is controlled to the basic throttle opening degree by the control of the throttle control means 901. Open gradually.

By performing the above control, the time during which the ignition timing is retarded becomes shorter and the amount of retardation due to the ignition timing can be greatly suppressed as compared with the case where the control according to the present invention is not performed. Also, by gradually returning the throttle opening, it is possible to minimize rebound to drivability.

FIG. 12 shows the throttle closing control release slice level Soff 'when the ignition timing returns to the basic ignition timing, that is, when the predetermined value is set to 0. The operation procedure is as described with reference to FIG.
In this control characteristic, the throttle closing control is performed until the basic ignition timing is reached, so that the intake characteristic of the engine is stabilized, so that the drivability is improved. However, since the ignition timing retard time becomes longer, it is more disadvantageous for the exhaust gas temperature, the output, and the fuel consumption than in the case of the control characteristics shown in FIG. However, compared to the case where there is no control according to the present invention, the time during which the ignition timing is retarded is shorter, and the amount of retardation due to the ignition timing can be greatly suppressed.

As described above, by using the knocking control means according to the present embodiment, it is possible to reduce the ignition timing retard amount and the time while avoiding knocking. Also,
By reducing the ignition timing retard amount, the compression ratio of the engine can be increased, and improvement in fuel efficiency and output can be expected. As described above, one embodiment of the present invention has been described.
The present invention is not limited to the above embodiments, and does not depart from the spirit of the invention described in the claims.
Various changes can be made in design and the like.

For example, it is possible to combine knocking control means using variable valve control means with knocking control means using throttle control means. Since the sensitivity to knocking is higher in the order of (1) ignition timing retard (2) intake valve retard (3) throttle closing, the initial knocking is avoided by ignition timing retard, and then the intake valve is retarded. By performing control such as closing the throttle at the end, the burden on each means can be reduced, driving performance can be further improved, knocking can be avoided, and the ignition timing retard amount and time can be reduced.

[0074]

As can be understood from the above description, according to the knocking control apparatus for an internal combustion engine according to the present invention, the ignition timing control means responds to the result of the determination by the knocking determination means, and if the determination result indicates that knocking has occurred. For example, if the ignition timing control means retards the ignition timing of the internal combustion engine and the ignition timing of the internal combustion engine is retarded, for example, if the ignition timing retard amount becomes a predetermined value or more, the variable valve control means Since the charging efficiency of the internal combustion engine is reduced by the charging efficiency variable means such as the throttle control means and the slot control means, it is possible to reduce the ignition timing retard amount and the ignition delay time due to knocking while ensuring engine operability. As a result, it is possible to minimize the rise in exhaust gas temperature, the deterioration in fuel efficiency, and the decrease in output caused by the ignition timing retard. In addition, the reduction in the ignition timing retard amount allows the engine to have a high compression ratio, so that improvement in fuel efficiency and output can be expected.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an overall configuration of an engine system including a knocking control device according to an embodiment of the present invention.

FIG. 2 is a functional configuration diagram of a knocking control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 3 is a flowchart of an ignition timing control operation of the knocking control device shown in FIG. 2;

FIG. 4 is a flowchart of a variable valve control operation using the ignition timing correction amount of the knocking control device shown in FIG. 2;

FIG. 5 is a graph showing an operation range of a variable valve timing.

FIG. 6 is a timing chart showing an operation range of variable valve timing.

FIGS. 7A to 7D are diagrams showing an example of an operation of variable valve control of the knocking device shown in FIG. 2;
Shows the knock determination result, (b) shows the relationship between the ignition timing and the variable valve control, (c) shows the intake valve retard request, and (d) shows the intake valve operation image.

8 (a) to 8 (d) are diagrams showing another example of the operation of the variable valve control of the knocking device shown in FIG. 2;
(A) shows the knock determination result, (b) shows the relationship between the ignition timing and the variable valve control, (c) shows the intake valve retard request, and (d)
Represents an operation image of the intake valve.

FIG. 9 is a functional configuration diagram of a knocking control device for an internal combustion engine according to another embodiment of the present invention.

FIG. 10 is a flowchart of a throttle control operation using the ignition timing correction amount of the knocking control device shown in FIG. 9;

FIGS. 11A to 11D are diagrams illustrating an example of an operation of variable valve control of the knocking device illustrated in FIG. 9;
(A) shows the knock determination result, (b) shows the relationship between the ignition timing and the throttle closing control, (c) shows the throttle closing request, and (d) shows the throttle motor operation image.

12A to 12D are diagrams showing another example of the operation of the variable valve control of the knocking device shown in FIG. 9;
(A) shows the knock determination result, (b) shows the relationship between the ignition timing and the throttle closing control, (c) shows the throttle closing request, and (d) shows the throttle motor operation image.

[Explanation of symbols]

 100. Engine 103. Air flow sensor 104. Throttle valve 110. Fuel injector 112. Ignition coil 113. Spark plug 114. Engine control device 115. Crank angle sensor 116. Crankshaft 117. Knock sensor 118. Variable valve control mechanism 119. Cam shaft 120. Throttle motor 121. Throttle valve device 122. Accelerator pedal 123. Intake valve 300. Knocking control device 303. Knock determination means 304. Ignition timing control means 501. Variable valve control means 901. Throttle control means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/22 320 F02D 41/22 320 F02P 5/152 F02P 5/15 D 5/153 (72) Inventor Yoshihiko Akagi 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. 3G022 DA02 EA02 EA04 GA01 GA05 GA06 GA08 GA09 GA13 GA14 3G084 BA05 BA17 BA23 DA01 DA02 DA37 DA38 FA07 FA10 FA20 FA25 FA33 FA38 3G092 AA01 BA09 DA01 DA08 DC03 EA04 EA14 EA15 EA22 FA16 FA24 FA38 HA01Z HA06Z HC05Z HE01Z HE03Z HE08Z HF08Z 3G301 HA01 HA19 JA01 JA02 JA22 JA32 LA00 LA03 LA07 MA12 PA01Z PA11Z PC08Z PE01Z PE03Z PE08Z PF03Z

Claims (9)

[Claims] 1. A knocking detecting means for detecting knocking vibration generated in an internal combustion engine, a knocking determining means for determining the presence or absence of knocking based on a knocking detection signal output from the knocking detecting means, and controlling an ignition timing of the internal combustion engine. A knocking control device for an internal combustion engine, comprising: an ignition timing control unit that performs ignition timing control; and a charging efficiency variable unit that can change a charging efficiency of the internal combustion engine. The ignition timing control unit responds to a determination result of the knocking determination unit. If the result of the determination is knocking, the ignition timing control means delays the ignition timing of the internal combustion engine, and the charging efficiency variable means sets the charging of the internal combustion engine in accordance with the retardation of the ignition timing of the internal combustion engine. A knocking control device for an internal combustion engine, which reduces efficiency. 2. The knocking control apparatus for an internal combustion engine according to claim 1, wherein said charging efficiency variable means is a variable valve control means for delaying the opening / closing timing of an intake valve of the internal combustion engine by an actuator. . 3. The variable valve control means retards the closing timing of an intake valve when the ignition timing control means determines that knocking is present and the ignition timing is retarded by a predetermined value or more. The knocking control device for an internal combustion engine according to claim 2, wherein 4. The knocking of an internal combustion engine according to claim 2, wherein the retard release of the closing timing of the intake valve is gradually performed from a point in time when the ignition timing retard amount is reduced to a predetermined value or less. Control device. 5. During knocking control, intake valve control by said variable valve control means according to the operating state of the internal combustion engine is prohibited, and intake valve retard control for avoiding knocking is preferentially performed. The knocking control device for an internal combustion engine according to claim 2, wherein: 6. The knocking control apparatus for an internal combustion engine according to claim 1, wherein said charging efficiency variable means is a throttle control means for reducing a throttle opening of the internal combustion engine by an actuator. 7. A throttle valve is closed by said throttle control means when knocking is determined by said knock determination means and ignition timing is retarded by a predetermined value or more by said ignition timing control means. 7. A knocking control device for an internal combustion engine according to claim 6. 8. The knocking control apparatus for an internal combustion engine according to claim 6, wherein the closing of the throttle valve is gradually performed from a point in time when the ignition timing retard amount decreases to a predetermined value or less. 9. During knocking control, throttle control by the throttle control means in accordance with the operating state of the internal combustion engine is prohibited, and throttle closing control for avoiding knocking is preferentially performed. Knocking control device for an internal combustion engine according to claim 1.