JPH10288138A - Knocking prevention device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent knocking by properly controlling cooling water temperature in accordance with a load of an internal combustion engine in consideration of a water temperature control state and variation of the load by a water temperature control mechanism free to change it. SOLUTION: This device increases and decreases cooling water quantity to be introduced to a radiator 23 in accordance with a load of an internal combustion engine 1 and gradually returns delay angle quantity against ignition timing to its original quantity after changing it larger than at the time of low water temperature control by an ECU 40 when it is transferred to high load travelling by acceleration, etc., at the time when it is high water temperature controlled by a water temperature control mechanism to maintain cooling water temperature against the internal combustion engine 1 high at the time of low load travelling and low at the time of high load travelling. Consequently, it is possible to prevent knocking without causing deterioration of drivability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing knocking of an internal combustion engine, and more particularly to a device for preventing knocking of an internal combustion engine in a device having a water temperature control mechanism capable of changing a cooling water temperature according to the load of the internal combustion engine. It is about.

[0002]

2. Description of the Related Art Conventionally, as a prior art document relating to a knocking prevention device for an internal combustion engine, Japanese Unexamined Utility Model Publication No. 58-2037 is disclosed.
No. 9 is known. In this system, a coolant temperature control mechanism (cooling device) that maintains the cooling water temperature of the internal combustion engine high during low-load driving to reduce friction loss and improves fuel efficiency, and that maintains the cooling water temperature low during high-load driving to prevent knocking of the internal combustion engine. ),
A technique is disclosed in which ignition timing is retarded for a predetermined time immediately after a transition from low load traveling to high load traveling to prevent knocking of the internal combustion engine.

[0003]

By the way, in the above-mentioned system, the water temperature is controlled in accordance with the load of the internal combustion engine, and a predetermined period is set at a predetermined timing immediately after shifting from low load running to high load running. When only retard control is performed, sometimes the drivability (Drivabilit
There was a problem that y) deteriorated.

Therefore, the present invention has been made to solve such a problem, and adaptive control is performed in consideration of a water temperature control state and a load fluctuation by a water temperature control mechanism capable of changing a cooling water temperature according to a load of an internal combustion engine. Accordingly, it is an object of the present invention to provide a knocking prevention device for an internal combustion engine that can prevent knocking of the internal combustion engine without deteriorating drivability.

[0005]

According to the knocking prevention apparatus for an internal combustion engine of the present invention, when the water temperature control mechanism controls the high water temperature, for example, when the vehicle shifts to high load running by acceleration, the retard amount changing means. , The retard amount with respect to the ignition timing is greatly changed from that at the time of the low water temperature control, and then gradually returned to the original value. Thus, knocking can be prevented without deteriorating drivability.

In the knocking prevention apparatus for an internal combustion engine according to the second aspect, the maximum allowable amount when the retard amount with respect to the ignition timing is changed by the retard amount changing means is set to be larger as the cooling water temperature is higher. As a result, the maximum allowable amount of change of the retard amount with respect to the ignition timing is appropriately set according to the cooling water temperature, and knocking can be prevented without deteriorating drivability.

According to the knocking prevention device for an internal combustion engine of claim 3, when the high water temperature prohibiting means determines that the vehicle is traveling uphill or running at high speed, the water temperature control mechanism is prohibited from shifting to the high water temperature side. Thus, knocking can be prevented without deteriorating drivability.

According to the knocking prevention apparatus for an internal combustion engine, when the water temperature is controlled by the water temperature control mechanism, the cooling fan is positively controlled by the cooling fan control means, and the outlet water temperature of the radiator is controlled by the low water temperature control. It is cooled so as to be lower than the cooling water temperature at the time. Accordingly, the internal combustion engine can be efficiently cooled immediately by using the low cooling water temperature regardless of the transition to the low water temperature control, so that knocking can be prevented without deteriorating drivability.

According to the knocking prevention apparatus for an internal combustion engine of the present invention, when the vehicle is running at a high load under the high water temperature control by the water temperature control mechanism, the opening speed of the throttle valve is slowed down by the intake charging efficiency control means. Knocking can be prevented without lowering drivability by reducing the intake charging efficiency in the engine.

According to the knocking prevention apparatus for an internal combustion engine of the present invention, when the vehicle is running under a high load under the high water temperature control by the water temperature control mechanism, the closing timing of the intake valve is advanced by the intake charging efficiency control means, so that the internal combustion engine In this case, knocking can be prevented without lowering drivability due to a decrease in intake air charging efficiency at the time.

According to the knocking prevention apparatus for an internal combustion engine of the present invention, when the water temperature control mechanism performs high-load running at the time of high water temperature control,
And, when knocking is detected by the knocking detection means, the retardation amount with respect to the ignition timing is gradually changed by the retardation amount changing means included in the retardation control means for retarding the ignition timing, and then gradually after the low water temperature control. It will be restored. Thus, knocking can be prevented without deteriorating drivability.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

Embodiment 1 FIG. 1 is a schematic diagram showing an overall configuration of a knocking prevention device for an internal combustion engine according to a first embodiment of the present invention.

In FIG. 1, an internal combustion engine 1 has an intake passage 2
And the exhaust passage 3 are connected. An air cleaner 4 is arranged at the most upstream side in the intake passage 2, a throttle valve 5 is arranged downstream thereof, and a surge tank 6 is provided in the middle of the intake passage 2. The internal combustion engine 1
Injector (fuel injection valve) that supplies fuel to each cylinder
7 are provided. Then, the air-fuel mixture introduced into the combustion chamber 9 of the internal combustion engine 1 from the intake passage 2 through the intake valve 8 is burned by the spark ignition of the spark plug 10,
The exhaust gas is discharged to the exhaust passage 3 through the exhaust valve 11. The ignition plug 10 is connected to a distributor 13 that supplies a high voltage generated by an igniter 12 corresponding to the rotational position of a crankshaft (not shown) of the internal combustion engine 1. Further, the throttle valve 5 is connected to a DC motor 14 which is an actuator driven based on an accelerator operation amount or the like, and forms a throttle control mechanism called an “electronic throttle system”. A well-known variable valve timing control mechanism 16 is connected to the camshaft 15 of the intake valve 8, and a crank angle signal from a crank angle sensor 36 described later and a cam angle sensor (not shown) provided on the camshaft 15. The variable valve timing control mechanism 16 is driven via a flow control valve 17 such as a spool valve using the lubricating oil of the internal combustion engine 1 as hydraulic oil based on the cam angle signal from , The relative rotation angle of the camshaft 15 is changed.

The cooling water in the internal combustion engine 1 is sent out by the water pump 21 to the radiator 23 through the outward flow path 22 and is cooled by the radiator 23 before being returned to the return flow path 2.
The temperature is maintained at a predetermined temperature by returning to the internal combustion engine 1 via the internal combustion engine 4. Here, the radiator 23 is provided with a cooling fan 25 and is driven as needed. A flow path switching valve 26 is provided in the middle of the outward flow path 22, and a predetermined amount of the cooling water delivered by the water pump 21 for maintaining the cooling water temperature of the internal combustion engine 1 at a predetermined temperature. Is returned to the internal combustion engine 1 side via the bypass passage 27 without passing through the radiator 23.

Immediately after the air cleaner 4 on the upstream side of the intake passage 2, an intake air temperature sensor 31 is provided, and the intake air temperature sensor 31 detects the intake air temperature of the intake air introduced into the intake passage 2. The throttle valve 5 is provided with a throttle opening sensor 32, and the throttle opening sensor 32 detects the throttle opening of the throttle valve 5. The surge tank 6 has an intake pressure sensor 3
The intake pressure sensor 33 detects the intake passage 2.
Is detected. Further, a water temperature sensor 34 is provided in the internal combustion engine 1, and the water temperature sensor 34 detects an internal water temperature (cooling water temperature) of the internal combustion engine 1. Further, a water temperature sensor 35 is provided on the outlet side of the radiator 23,
The radiator outlet water temperature on the outlet side of the radiator 23 is detected by the water temperature sensor 35.

The distributor 13 is provided with a crank angle sensor 36 and a cylinder discrimination sensor 37. The crank angle sensor 36 discriminates the engine rotation speed of the internal combustion engine 1 and the cylinder discrimination sensor 37 determines a predetermined cylinder timing of the internal combustion engine 1. Is done. The internal combustion engine 1 has a knock sensor 3
The knock sensor 38 detects a knock signal from the internal combustion engine 1. An oxygen concentration sensor 39 is provided in the exhaust passage 3, and detects the oxygen concentration in the exhaust gas.

The intake air temperature signal from the intake air temperature sensor 31, the throttle opening signal from the throttle opening sensor 32, the intake pressure signal from the intake pressure sensor 33, and the water temperature sensor 3
4, a radiator outlet water temperature signal from a water temperature sensor 35, an engine rotation speed signal from a crank angle sensor 36, a cylinder discrimination signal from a cylinder discrimination sensor 37,
Various sensor signals such as a knock signal from the knock sensor 38 and an oxygen concentration signal from the oxygen concentration sensor 39 are supplied to the ECU.
(Electronic Control Unit: electronic control unit) 40.

The ECU 40 includes a CPU 41 as a well-known central processing unit, a ROM 42 storing a control program,
It is configured as a logic operation circuit mainly including a RAM 43 for storing various data, a B / U (backup) RAM 44, and the like. An input / output circuit 45 for inputting detection signals from various sensors and outputting control signals to various actuators is provided. It is connected via a bus 46. And ECU
40, a fuel injection signal for the injector 7, an ignition timing signal for the igniter 12, a relative rotation angle feedback signal for the flow control valve 16, and a drive for the cooling fan 25 based on the various sensor signals input thereto. A channel switching signal and the like are output to the signal and the channel switching valve 26, respectively.

Next, based on a flowchart of FIG. 2 showing a processing procedure of the retard amount control in the CPU 41 in the ECU 40 used in the knocking prevention device for the internal combustion engine according to the first embodiment of the present invention. This will be described with reference to the time chart of FIG. Note that this retard amount control routine is repeatedly executed by the CPU 41 at predetermined time intervals.

In FIG. 2, first, in step S101, it is determined whether the cooling water temperature is equal to or higher than a predetermined value α. When the determination condition of step S101 is satisfied and the cooling water temperature is maintained at the high water temperature side at the predetermined value α or higher and the high water temperature control is being performed (shown by a solid line before time t1 in FIG. 3), the process proceeds to step S102. It is determined whether the load of the internal combustion engine is equal to or greater than a predetermined value β. Here, the magnitude of the load of the internal combustion engine is determined by, for example, a throttle opening signal from the throttle opening sensor 32 due to acceleration or the intake pressure sensor 3.
3 can be known based on the intake pressure signal and the like.

When the determination condition of step S102 is satisfied and the load of the internal combustion engine is determined to be higher than the predetermined value β and the vehicle is running under a high load (time t1 to time t2 in FIG. 3), the process proceeds to step S103. , The retard amount expansion control determination flag XKC
It is determined whether SH is “0”. Step S103
If the determination condition is satisfied and the retard amount expansion control is not being executed, the process proceeds to step S104, and the retard amount is increased by γ (shown by a solid line from time t1 to time t2 in FIG. 3). The amount of retard attenuation for returning the amount of retard is δ
(Shown by a solid line from time t2 to time t4 in FIG. 3). Next, the process proceeds to step S105, where the retard amount MAX guard value, which is the maximum allowable amount of the change of the retard amount, is calculated from a map based on the cooling water temperature at that time. Next, the routine proceeds to step S106, where the retard amount expansion control determination flag X
KCSH is set to "1", and this routine ends. Here, if the determination condition of step S103 is not satisfied and the retard amount expansion control has already been executed, this routine ends without performing any operation.

On the other hand, step S101 or step S101
When the determination condition of 102 is not satisfied, step S10
Then, it is determined whether the retard amount expansion control determination flag XKCSH is “1”. If the determination condition of step S107 is satisfied and the retard amount enlargement control has already been executed, the process proceeds to step S108, where the retard amount is decreased by γ and the retard attenuation is increased by δ. Next, the process proceeds to step S109, where the retard amount MAX guard value is returned to the original value ε. Next, the routine proceeds to step S110, where the retard amount expansion control determination flag XKCSH is set to "0", and this routine ends. Here, when the determination condition of step S107 is not satisfied and the retard amount expansion control is not being executed, this routine ends without performing any operation. In addition,
As shown by the broken line in FIG. 3, in the normal retard control, the retard amount is not largely changed as in the retard amount enlargement control, and the retard attenuation amount for returning the retard amount to the original amount is also increased. You.

As described above, the knocking prevention apparatus for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1 and increases the cooling water temperature for the internal combustion engine 1 during low load driving. , Water temperature sensors 34, 3 as various sensors to keep low during high load traveling
5. ECU 40 to which these signals are input, ECU 40
A water temperature control mechanism constituted by a flow path switching valve 26 or the like as an actuator controlled by an output signal from the controller, and a high water temperature control mechanism for maintaining the cooling water temperature for the internal combustion engine 1 on the high water temperature side by the water temperature control mechanism. When the vehicle shifts to the load running, the ECU 40 includes a retard amount changing unit that is achieved by the ECU 40 that largely changes the retard amount with respect to the ignition timing from the low water temperature control that maintains the cooling water temperature on the low water temperature side and then gradually returns the retard amount to the original timing. Is what you do.

That is, when the vehicle shifts to high-load running due to acceleration or the like while the water temperature control mechanism is controlling the high water temperature, the ECU 40 which achieves the retard amount changing means makes the retard amount with respect to the ignition timing larger than in the low water temperature control. It is gradually restored after being changed. Thus, knocking can be prevented without deteriorating drivability.

In the knocking prevention apparatus for an internal combustion engine according to the present embodiment, the maximum allowable amount when the retard amount changing means achieved by the ECU 40 changes the retard amount with respect to the ignition timing is set as the cooling water temperature becomes higher. It is set to be large. That is, since the knocking is more likely to occur in the internal combustion engine 1 as the cooling water temperature becomes higher, the maximum allowable amount is set to be large so that the retard amount can be largely changed. As described above, the maximum allowable amount of the change in the retard amount with respect to the ignition timing is appropriately set in accordance with the cooling water temperature, and knocking can be prevented without deteriorating drivability.

FIG. 4 is a flowchart showing ignition timing retard control based on knock detection by knock sensor 38.

In FIG. 4, first, it is determined in step S201 whether knocking has occurred. Here, the determination of the presence or absence of knocking is performed, for example, in Japanese Unexamined Patent Application Publication No. 5-26440.
As described in Japanese Patent Laid-Open Publication No. 5 (1999) -2005, it is determined that knocking has occurred when the knocking signal detected by knock sensor 38 is equal to or greater than a predetermined determination value. Step S
When knocking has occurred in step 201, step S
The routine proceeds to 202, where the ignition timing is retarded based on the retard amount calculated in FIG. 2, and this routine ends. On the other hand, when knocking has not occurred in step S201, the process proceeds to step S203, in which the ignition timing is advanced by a predetermined amount,
This routine ends.

As described above, the knocking prevention apparatus for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1 and increases the cooling water temperature for the internal combustion engine 1 during low load driving. , Water temperature sensors 34, 3 as various sensors to keep low during high load traveling
5. ECU 40 to which these signals are input, ECU 40
A water temperature control mechanism constituted by a flow path switching valve 26 or the like as an actuator controlled by an output signal from the engine, a knock sensor 38 as a knocking detecting means for detecting knocking generated in the internal combustion engine 1, and a knock sensor 38 When knocking is detected in the ECU, the ignition timing is retarded by a predetermined amount by an ECU 40. The retard control means is provided for the internal combustion engine 1 by the water temperature control mechanism. When the vehicle shifts to high-load running during high water temperature control for maintaining the cooling water temperature on the high water temperature side, and when knocking is detected by the knock sensor 38, the ignition timing is changed from the low water temperature control for maintaining the cooling water temperature to the low water temperature side. It is provided with a retard amount changing means for gradually changing the retard amount and then gradually returning the retard amount to the original value.

That is, when the water temperature control mechanism runs under a high load under high water temperature control and knocking is detected by the knock sensor 38, the ignition timing is retarded by the retard control means.
After the retard amount with respect to the ignition timing is changed by the retard amount changing means included in the CU 40 to be larger than that during the low water temperature control, the retard amount is gradually returned to the original value. Thus, knocking can be prevented without deteriorating drivability.

In the above embodiment, the amount of retardation with respect to the ignition timing is largely changed and then gradually returned to the original value, but the amount of retardation attenuation is reduced. However, by gradually increasing the retardation attenuation time, the amount of retardation is gradually increased. May be returned.

In this embodiment, the knocking is determined by using the output of the knock sensor 38. For example, the knocking is determined by using an ionic current as described in Japanese Patent Application Laid-Open No. 58-7536. You may do so.

<Embodiment 2> FIG. 5 is a flowchart showing a procedure for prohibiting high water temperature in the CPU 41 in the ECU 40 used in the knocking prevention device for an internal combustion engine according to a second embodiment of the present invention. It is. In addition,
This high water temperature prohibition routine is repeatedly executed by the CPU 41 at predetermined time intervals. Further, the configuration of the knocking prevention device for an internal combustion engine according to the present embodiment is the same as the schematic diagram of FIG. 1 in the above-described first embodiment, and a detailed description thereof will be omitted.

In FIG. 5, first, in step S301, it is determined whether the load of the internal combustion engine 1 is equal to or greater than a predetermined value α. If the condition of step S301 is not satisfied and the load of the internal combustion engine 1 is low and the load is less than the predetermined value α, the process proceeds to step S302, and the throttle opening detected by the throttle opening sensor 32 is set in advance. It is determined whether it is equal to or greater than the predetermined value β. Step S30
If the determination condition 2 is not satisfied and the throttle opening is in the low opening state with the value less than the predetermined value β, the process proceeds to step S303, and it is determined whether the vehicle speed is equal to or more than the predetermined value γ. If the determination condition of step S303 is not satisfied and the vehicle speed is lower than the predetermined value γ and the vehicle is in a low speed state, step S3
04, it is determined whether or not a high water temperature prohibition flag XTHWH that prohibits the water temperature control mechanism from shifting the cooling water temperature to the high water temperature side for the internal combustion engine 1 is “0”. If the determination condition of step S304 is not satisfied and the water temperature increase is not prohibited, the process proceeds to step S305, and a process of permitting the water temperature increase is executed. When this high water temperature is allowed,
By increasing the ratio of the cooling water that bypasses the radiator 23 and passes through the bypass flow path 27 by the flow path switching valve 26, the cooling water temperature for the internal combustion engine 1 is maintained high. Next, the process proceeds to step S306, and the high water temperature prohibition flag X
THWH is set to "0", and this routine ends. Here, when the determination condition of step S304 is satisfied and the increase of the water temperature is prohibited, the present routine ends without performing any operation.

On the other hand, step S301 or step S301
When the determination condition of step 302 or step S303 is satisfied, the process proceeds to step S307, and it is determined whether the water temperature increase inhibition flag XTHWH is "1". Step S
When the determination condition of 307 is not satisfied and the water temperature increase is being prohibited, the process proceeds to step S308, and a process of prohibiting the water temperature increase is executed. When the high water temperature is prohibited, the ratio of the cooling water sent to the radiator 23 by the flow path switching valve 26 is increased, so that the cooling water temperature for the internal combustion engine 1 is maintained low. Next, the flow shifts to step S309, where the water temperature increase prohibition flag XTHWH is set to "1", and this routine ends. Here, when the determination condition of step S307 is satisfied and the high water temperature is not prohibited, the routine ends without performing any operation.

As described above, the knocking prevention device for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1 and increases the cooling water temperature for the internal combustion engine 1 during low load driving. , Water temperature sensors 34, 3 as various sensors to keep low during high load traveling
5. ECU 40 to which these signals are input, ECU 40
A water temperature control mechanism constituted by a flow path switching valve 26 or the like as an actuator controlled by an output signal from the controller, and a high water temperature of a cooling water temperature for the internal combustion engine 1 by the water temperature control mechanism when it is determined that the vehicle is traveling uphill or running at high speed. And a means for inhibiting high water temperature achieved by the ECU 40 for inhibiting the shift to the side.

That is, when the load of the internal combustion engine 1 is high, the throttle opening at this time is large, and the vehicle speed is high and it is determined that the vehicle is running uphill or running at high speed, the ECU 40 that implements the means for inhibiting water temperature increase is controlled by the water temperature control mechanism. The shift to the high water temperature side due to is prohibited. Thus, knocking can be prevented without deteriorating drivability.

In the above-described embodiment, the determination of traveling uphill or traveling at high speed is made based on the load of the internal combustion engine 1, the throttle opening, and the vehicle speed. However, the present invention is not limited to this. Instead, the determination may be performed based on the intake air amount (intake air amount) detected by an air flow meter or the like (not shown), the fuel injection amount from the injector 7, the gear position of the transmission, the engine speed, and the like.

<Embodiment 3> FIG. 6 shows a processing procedure for controlling the cooling fan of the radiator 23 in the CPU 41 in the ECU 40 used in the knocking prevention device for an internal combustion engine according to the third embodiment of the present invention. FIG. 8 is a flowchart showing the process, which will be described with reference to the time chart of FIG. This cooling fan control is executed every predetermined time by the CPU 4.
1 is repeatedly executed. Further, the configuration of the knocking prevention device for an internal combustion engine according to the present embodiment is the same as the schematic diagram of FIG. 1 in the above-described first embodiment, and a detailed description thereof will be omitted.

In FIG. 6, first, in step S401, it is determined whether or not the engine water temperature, which is the cooling water temperature in the internal combustion engine 1, is equal to or higher than a predetermined value α. Here, when the determination condition of step S401 is not satisfied and the engine internal water temperature is lower than the predetermined value α and the engine is in a low water temperature state, this routine ends without performing any operation. On the other hand, when the determination condition of step S401 is satisfied and the engine water temperature is high, step S4
02, it is determined whether the radiator outlet water temperature is equal to or higher than a predetermined value β set in advance. When the determination condition in step S402 is satisfied and the radiator outlet water temperature is higher than the predetermined value β and is in a high water temperature state (time t11 in FIG. 7), the process proceeds to step S403, and the cooling fan drive flag XRFAN
It is determined whether H is "0". When the determination condition of step S403 is satisfied and the cooling fan is not being driven, the process proceeds to step S404, and the cooling fan 25 of the radiator 23 is turned on (driven) (time t11 to time t1 in FIG. 7).
2). Next, the routine proceeds to step S405, where the cooling fan drive flag XRFANH is set to "1", and this routine ends. Here, when the determination condition of step S403 is not satisfied and the cooling fan is already being driven, this routine ends without performing any operation.

On the other hand, when the determination condition of step S402 is not satisfied and the radiator outlet water temperature is lower than the predetermined value β and is in a low water temperature state, the process proceeds to step S406, and furthermore, the radiator outlet water temperature is equal to or higher than the predetermined value γ. Is determined. If the determination condition of step S406 is not satisfied and the radiator outlet water temperature is lower than the predetermined value γ and is in a low water temperature state (time t12 in FIG. 7), the process proceeds to step S407, and the cooling fan 25 of the radiator 23 is turned off (stopped). (Before time t11 in FIG. 7, time t12 to time t1)
3). Next, the routine proceeds to step S408, where the cooling fan drive flag XRFANH is set to "0", and this routine ends. Here, when the determination condition of step S406 is satisfied and the radiator outlet water temperature is equal to or higher than the predetermined value γ and lower than the predetermined value β, the routine is terminated without any operation because the temperature is in the proper temperature state.

As described above, the knocking prevention device for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1 and increases the cooling water temperature for the internal combustion engine 1 during low load driving. , Water temperature sensors 34, 3 as various sensors to keep low during high load traveling
5. ECU 40 to which these signals are input, ECU 40
A water temperature control mechanism composed of a flow path switching valve 26 or the like as an actuator controlled by an output signal from the controller, and a radiator for high water temperature control in which the cooling water temperature for the internal combustion engine 1 is maintained on the high water temperature side by the water temperature control mechanism. And cooling fan control means achieved by the ECU 40 for controlling the cooling fan 25 of the radiator 23 such that the outlet water temperature of the cooling water 23 is lower than when the cooling water temperature for the internal combustion engine 1 is maintained on the low water temperature side. is there.

That is, when the cooling water temperature of the internal combustion engine 1 is controlled to a high water temperature by the water temperature control mechanism, the cooling fan 25 is positively controlled by the ECU 40 which achieves the cooling fan control means, and the outlet water temperature of the radiator 23 becomes low water temperature. The cooling is performed so as to be lower than the cooling water temperature during control. Thus, the internal combustion engine 1 can be efficiently cooled immediately using the low cooling water temperature regardless of the transition to the low water temperature control, and knocking can be prevented without deteriorating drivability.

In the above embodiment, the radiator 2
The cooling fan 25 is controlled on the basis of the outlet water temperature of the internal combustion engine 1.
May be controlled.

<Embodiment 4> FIG. 8 shows a processing procedure of intake air charging efficiency reduction control in the CPU 41 in the ECU 40 used in the knocking prevention device for an internal combustion engine according to the fourth embodiment of the present invention. It is a flowchart. Note that this intake air charging efficiency reduction control is performed every predetermined time.
It is repeatedly executed by the PU 41. Further, the configuration of the knocking prevention device for an internal combustion engine according to the present embodiment is the same as the schematic diagram of FIG. 1 in the above-described first embodiment, and a detailed description thereof will be omitted.

In FIG. 8, first, in step S501, it is determined whether the temperature of the cooling water in the internal combustion engine 1 is equal to or higher than a predetermined value α. When the determination condition of step S501 is satisfied and the cooling water temperature is maintained at the high water temperature side at the predetermined water temperature or higher and the high water temperature control is being performed, the process proceeds to step S502, and the throttle opening change amount is equal to or more than the predetermined predetermined value β. Is determined. Here, the magnitude of the throttle opening change amount can be known based on the deviation of the throttle opening signal from the throttle opening sensor 32 per predetermined time per predetermined time. If the determination condition of step S502 is satisfied and the throttle opening change amount is a predetermined value β or more and is a high opening change amount, the process proceeds to step S503,
It is determined whether the intake charging efficiency reduction control flag XTASH is “0”. If the determination condition of step S503 is satisfied and the intake charge efficiency reduction control is not being performed, step 5
04, the amount of change in the throttle opening is reduced by γ by controlling the throttle opening of the throttle valve 5 by the DC motor 14, or the variable valve timing control mechanism 16 is driven by the flow control valve 17 and the camshaft 1
5 is changed and the intake valve closing timing becomes δ
Only be enlarged. Next, the process proceeds to step S505.
The intake charge efficiency reduction control flag XTASH is set to "1", and this routine ends. Here, step S503
If the determination condition is satisfied and the intake charge efficiency reduction control is already being performed, this routine is terminated without any operation.

On the other hand, step S501 or step S501
If the determination condition of 502 is not satisfied, step S5
06, the flag XTAS under the intake charging efficiency reduction control
It is determined whether H is "1". If the determination condition of step S506 is satisfied and the intake charging efficiency reduction control is being performed, the process proceeds to step S507, where the throttle opening change amount is increased by γ or the intake valve closing timing is decreased by δ, and the original throttle opening change is performed. It is returned to the quantity or intake valve closing timing. Next, the routine proceeds to step S508, where the intake filling efficiency lowering control flag XTASH is set to "0", and this routine ends. Here, when the determination condition of step S506 is satisfied and the intake charge efficiency reduction control is not being performed, this routine ends without performing any operation.

As described above, the knocking prevention device for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1 and increases the cooling water temperature for the internal combustion engine 1 during low load driving. , Water temperature sensors 34, 3 as various sensors to keep low during high load traveling
5. ECU 40 to which these signals are input, ECU 40
A water temperature control mechanism constituted by a flow path switching valve 26 or the like as an actuator controlled by an output signal from the controller, and a high water temperature control mechanism for maintaining the cooling water temperature for the internal combustion engine 1 on the high water temperature side by the water temperature control mechanism. When it is determined that the vehicle is running under load, the ECU 40 is provided with an intake charging efficiency control means that is achieved by the ECU 40 that reduces the valve opening speed of the throttle valve 5 and reduces the intake charging efficiency.

That is, when the vehicle is running at a high load under the high water temperature control by the water temperature control mechanism, the ECU 40 which achieves the intake charging efficiency control means slows down the opening speed of the throttle valve 5, that is, the amount of change in the throttle opening is reduced. In addition, knocking can be prevented without lowering drivability by reducing the intake charging efficiency of the internal combustion engine 1.

The knocking prevention device for an internal combustion engine according to the present embodiment increases or decreases the amount of cooling water introduced into the radiator 23 in accordance with the load on the internal combustion engine 1, and increases the cooling water temperature for the internal combustion engine 1 during low-load running and increases the cooling water temperature. Water temperature sensors 34 and 35 as various sensors for keeping the load low during load running, an ECU 40 to which these signals are input, a flow path switching valve 26 as an actuator controlled by an output signal from the ECU 40, and the like. When the control mechanism and the water temperature control mechanism determine that the vehicle is running under high load during high water temperature control in which the cooling water temperature for the internal combustion engine 1 is maintained on the high water temperature side, the ECU 40 advances the closing timing of the intake valve 8 to reduce the intake charging efficiency. And an intake charging efficiency control means achieved by the above.

That is, when the vehicle is running under a high load at the time of high water temperature control by the water temperature control mechanism, the closing timing of the intake valve 8 is advanced using the variable valve timing control mechanism 16 by the ECU 40 which achieves the intake charge efficiency control means. Since the intake charging efficiency of the internal combustion engine 1 is reduced, knocking can be prevented without deteriorating drivability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a knocking prevention device for an internal combustion engine according to first to fourth examples of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an E used in a knocking prevention device for an internal combustion engine according to a first embodiment of the present invention.
9 is a flowchart showing a processing procedure of retard amount control in a CPU in a CU.

FIG. 3 is a time chart of the retard amount control in the knocking prevention device for the internal combustion engine according to the first example of the embodiment of the present invention.

FIG. 4 is a diagram showing E used in a knocking prevention device for an internal combustion engine according to a first embodiment of the present invention.
9 is a flowchart illustrating a processing procedure of ignition timing retard control based on knocking detection in a CPU in a CU.

FIG. 5 is a diagram showing E used in a knocking prevention device for an internal combustion engine according to a second embodiment of the present invention.
It is a flowchart which shows the processing procedure of high water temperature prohibition in CPU in CU.

FIG. 6 is a diagram showing E used in a knocking prevention device for an internal combustion engine according to a third embodiment of the present invention.
5 is a flowchart illustrating a processing procedure of controlling a cooling fan of a radiator in a CPU in a CU.

FIG. 7 is a time chart of radiator cooling fan control in the knocking prevention device for an internal combustion engine according to the third example of the embodiment of the present invention.

FIG. 8 is a diagram showing E used in a knocking prevention device for an internal combustion engine according to a fourth embodiment of the present invention.
5 is a flowchart illustrating a processing procedure of intake charging efficiency reduction control in a CPU in a CU.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 5 Throttle valve 8 Intake valve 14 DC motor 16 Variable valve timing control mechanism 23 Radiator 25 Cooling fan 26 Flow path switching valve 32 Throttle opening sensor 33 Intake pressure sensor 38 Knock sensor 40 ECU (Electronic control device)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/04 310 F02D 45/00 345B 45/00 345

Claims (7)

[Claims] 1. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced to a radiator according to the load of an internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low load running and low during high load running, In the mechanism, when shifting to high load traveling during high water temperature control for maintaining the cooling water temperature for the internal combustion engine on the high water temperature side, the amount of retardation with respect to the ignition timing was changed larger than during low water temperature control for maintaining the cooling water temperature at the low water temperature side. A knocking prevention device for an internal combustion engine, comprising: a retard amount changing means for gradually returning the amount to the initial value. 2. The internal combustion engine according to claim 1, wherein the retard amount changing means sets a maximum allowable amount when changing the retard amount with respect to the ignition timing as the cooling water temperature increases. Anti-knocking device. 3. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced into the radiator in accordance with the load of the internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low-load running and low during high-load running. An anti-knocking device for an internal combustion engine, comprising: a high water temperature prohibition unit that prohibits a shift of a cooling water temperature to a high water temperature side of the internal combustion engine by the water temperature control mechanism when it is determined that the vehicle is traveling at high speed. 4. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced into the radiator in accordance with the load of the internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low-load running and low during high-load running. The cooling fan of the radiator is configured such that at a high water temperature control in which a cooling water temperature for the internal combustion engine is maintained at a high water temperature side by a mechanism, an outlet water temperature of the radiator is lower than when the cooling water temperature for the internal combustion engine is maintained at a low water temperature side. A knocking prevention device for an internal combustion engine, comprising: 5. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced into the radiator in accordance with the load of the internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low-load running and low during high-load running, An intake charging efficiency control means for reducing the valve opening speed of the throttle valve when the high water temperature control for maintaining the cooling water temperature with respect to the internal combustion engine on the high water temperature side and for reducing the intake valve charging efficiency is performed. Knocking prevention apparatus for an internal combustion engine. 6. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced into the radiator in accordance with the load on the internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low-load running and low during high-load running. When the high water temperature control for maintaining the cooling water temperature for the internal combustion engine on the high water temperature side is determined by the mechanism, when it is determined that the vehicle is running under a high load, the intake valve closing timing is advanced to reduce the intake charging efficiency. A knocking prevention device for an internal combustion engine, characterized in that: 7. A water temperature control mechanism for increasing or decreasing the amount of cooling water introduced to a radiator according to the load of the internal combustion engine, and maintaining the cooling water temperature for the internal combustion engine high during low load driving and low during high load driving, Knocking detection means for detecting the occurrence of knocking, and a delay control means for delaying the ignition timing by a predetermined delay amount when the knock detection is detected by the knock detection means, wherein the retard control means comprises: When the water temperature control mechanism shifts to high load traveling during high water temperature control for maintaining the cooling water temperature for the internal combustion engine on the high water temperature side, and when knocking is detected by the knocking detection means, the cooling water temperature is lowered to the low water temperature side. The internal combustion engine is characterized in that the internal combustion engine further comprises a retard amount changing means for changing the retard amount with respect to the ignition timing more largely than at the time of the low water temperature control for maintaining the ignition timing and gradually returning the retard amount to the original value. Knock prevention device.