JP3401911B2 - Control device for transient knock suppression of internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transient knock suppression control device for an internal combustion engine, and more particularly to a transient knock suppression control device for an internal combustion engine, which is suitable for suppressing transient knock that occurs during acceleration of a vehicle internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a technique for suppressing knocking by controlling the ignition timing of an internal combustion engine is known, and in an internal combustion engine, knocking occurs during acceleration from an idle state under a predetermined high temperature environment. It is known to be easy.

On the other hand, for example, JP-A-3-1050
No. 63 discloses that when the ambient temperature detected by the cooling water temperature or the intake air temperature of the internal combustion engine is high and a high load exceeding a predetermined level is required for the internal combustion engine in the idle state, that is, the internal combustion engine in the idle state. There is disclosed a device for suppressing knocking (hereinafter, referred to as transient knock) that occurs during an acceleration transition period by retarding the ignition timing thereafter compared to a normal time when an acceleration request is made to the engine.

That is, when the internal combustion engine in a high temperature environment changes from the idle state to the acceleration state, knocking is likely to occur due to a rapid increase in the intake air amount, but the ignition timing is retarded at that time. Thus, the combustion speed of the fuel in the combustion chamber is delayed to suppress knocking.

[0005]

However, retardation of the ignition timing causes deterioration of combustibility in the combustion chamber. Therefore,
Such ignition timing retard control needs to be executed within an appropriate range from the viewpoint of misfire prevention.

Therefore, in the above-mentioned conventional apparatus, for example, when the idling state continues for a long period of time and the temperature in the combustion chamber rises, or when the internal combustion engine cooling fan operates, the ambient temperature in the engine room rises. As a result, when the intake air temperature further rises, especially in the situation where transient knock is likely to occur at the time of starting and accelerating, it is not possible to secure a sufficient amount of retard angle to suppress knock, and transient knock cannot be suppressed Had a problem.

The present invention has been made in view of the above points, and when both the intake air temperature and the cooling water temperature of the internal combustion engine are high, it is determined that the transient knock is likely to occur, and the ignition timing in the idle state is determined. To prevent the temperature rise in the combustion chamber before the acceleration request is generated, or to increase the idle speed to improve the transient knock resistance at the time of starting, or to increase the fuel amount during acceleration. An object of the present invention is to provide a transient knock suppression control device for an internal combustion engine that solves the above-mentioned problems by reducing the amount of correction for a predetermined period.

[0008]

1 to 3 are diagrams showing the principle configuration of a transient knock suppression control device for an internal combustion engine which achieves the above-mentioned object. That is, the above-mentioned objects are, as shown in FIG. 1, idle state detecting means M1 for detecting that the internal combustion engine is in an idle state, intake air temperature detecting means M2 for detecting the intake air temperature of the internal combustion engine, and cooling water temperature of the internal combustion engine. When the intake water temperature and the cooling water temperature are both equal to or higher than a predetermined temperature, the ignition timing in the idle state is set to be smaller than the intake air temperature and the cooling water temperature.
Also, an ignition timing calculating means M4 that is set on the retard side as compared with the case where one of them is lower than the predetermined temperature, and an ignition timing that controls the ignition timing of the internal combustion engine to the timing set by the ignition timing calculating means M4. This is achieved by a transient knock suppression control device for an internal combustion engine that includes a control means M5.

Further, the above-mentioned purpose is as shown in FIG.
Idle state detection means M1 for detecting that the internal combustion engine is in an idle state, intake air temperature detection means M2 for detecting the intake air temperature of the internal combustion engine, cooling water temperature detection means M3 for detecting the cooling water temperature of the internal combustion engine, When both the air temperature and the cooling water temperature are equal to or higher than a predetermined temperature, the idle speed calculation means M6 that determines the engine speed in the idle state to be high speed
And a transient knock suppression control device for an internal combustion engine, which includes an engine speed and an idle speed control means M7 for controlling the engine speed to a speed determined by the idle speed calculation means M6.

Further, the above-mentioned purpose is as shown in FIG.
An intake air temperature detecting means M2 for detecting an intake air temperature of the internal combustion engine, a cooling water temperature detecting means M3 for detecting a cooling water temperature of the internal combustion engine,
During acceleration of the internal combustion engine, an acceleration injection amount correction means M9 for increasing and correcting the fuel injection amount, and a correction for reducing the increase correction amount during acceleration for a predetermined period when both the intake air temperature and the cooling water temperature are above a predetermined temperature. This is also achieved by a transient knock suppression control device for an internal combustion engine, which includes a quantity reduction means.

[0011]

In the transient knock suppression control system for the internal combustion engine according to the first aspect of the present invention, the intake air temperature detected by the intake air temperature detecting means M2 becomes high in the vicinity of the intake port of air and the vicinity of the intake passage. This is when the temperature around the internal combustion engine is high.

Further, when the intake air temperature is high, the temperature inside the combustion chamber of the internal combustion engine, which is supplied with the air, tends to be high.
Therefore, the higher the intake air temperature detected by the intake air temperature detecting means M2 is, the more the internal combustion engine is placed in the environment where the transient knock is likely to occur.

On the other hand, the cooling water temperature detected by the cooling water temperature detecting means M3 is a substitute characteristic value of the temperature of the internal combustion engine body. Therefore, the higher the cooling water temperature detected by the cooling water temperature detecting means M3, the more likely the internal combustion engine itself is to cause a transient knock.

On the other hand, the ignition timing calculation means M4
Is the ignition timing in the idle state when the intake air temperature and the cooling water temperature are equal to or higher than a predetermined temperature .
It is set on the retard side as compared with the case where at least one of them is lower than the predetermined temperature . Then, the determined ignition timing is realized by the ignition timing control means M5. here,
When the ignition timing of the internal combustion engine is retarded, the temperature of the inner wall of the combustion chamber becomes lower than when the ignition timing is not retarded.

Therefore, when it is detected that the internal combustion engine itself and the environment of the internal combustion engine are likely to cause transient knock, as a result, the ignition timing calculation means M4 and the ignition timing control means M5 are operated at the idle time. In this case, the retarded ignition timing is realized, the inner wall temperature of the combustion chamber is maintained at a relatively low temperature, and a situation in which transient knock is unlikely to occur is formed.

Further, in the invention according to claim 2, the detection result of the idle state detection means M1, the detection result of the intake air temperature detection means 2 and the detection result of the cooling water temperature detection means 3 are the idle speed calculation. Is supplied to the means M6.

When it is judged from these detection results that the internal combustion engine itself and the environment of the internal combustion engine are in a state where transient knock is likely to occur, the idle speed calculation means M6 and the idle speed control means. A relatively high idle speed is realized by M7.

In an internal combustion engine, if the ignition timing is advanced at the same amount, knocking is less likely to occur in a region near the idle rotation speed as the rotation speed increases. Therefore, when the idle speed is increased as described above, a state in which transient knock is hardly generated is formed.

Further, in the third aspect of the present invention, the acceleration injection amount correction means M9 performs an increase correction of the fuel injection amount in order to secure good acceleration characteristics when an acceleration request is generated in the internal combustion engine. .

On the other hand, the correction amount reduction means M10 reduces the acceleration increase correction by the acceleration injection amount correction means M9 for a predetermined period when both the intake air temperature and the cooling water temperature are equal to or higher than a predetermined temperature.

Therefore, when the internal combustion engine is in a predetermined high temperature state and transient knock is likely to occur, the fuel is corrected to the lean side for a predetermined period after the start of acceleration, and the transient knock is suppressed. Further, since the normal increase correction during acceleration is performed after the elapse of the predetermined period, the acceleration characteristic of the internal combustion engine is maintained at an appropriate level without wobbling.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 shows an overall configuration diagram of an internal combustion engine 10 equipped with a transient knock suppression control system according to an embodiment of the present invention.
In the intake passage 12 of the internal combustion engine 10, an intake pressure sensor 14 that detects the pressure of air that flows inside the intake passage 12, an intake temperature sensor 16 that detects the temperature of the air that flows, a throttle valve 18 that controls the amount of air that flows, and an intake air An injector 20 for supplying fuel is provided in the passage 12.

The throttle valve 18 is a valve element which operates in conjunction with an accelerator pedal (not shown), and an idle switch 22 for detecting the fully closed state of the throttle valve 18 is provided in the vicinity of the throttle valve 18.

Further, the intake passage 12 is provided with a bypass passage 24 that bypasses the throttle valve 18. The bypass passage 24 is provided to circulate air that can maintain the internal combustion engine 10 in an idle state when the throttle valve 18 is fully closed, and uses, for example, a step motor as a drive source. The idle speed control valve (ISCV) 26 controls the conduction state.

The cylinder block 28 of the internal combustion engine 10 is provided with a water jacket 30 for cooling the engine by circulating cooling water. And
A water temperature sensor 32 is provided on the side wall of the water jacket 30 to detect the temperature of the cooling water flowing therein.

A combustion chamber 36 having a spark plug 34 protruding therefrom is formed above the piston 31 which slides up and down in the cylinder block 28. This combustion chamber 36
Communicates with the above-described intake passage 12 through the intake valve 38, and also communicates with the exhaust passage 42 through the exhaust valve 40.

In the exhaust passage 42, an oxygen concentration sensor 44 for detecting the oxygen concentration contained in the exhaust gas flowing through the exhaust passage 42, and a catalyst device 46 for purifying unburned components in the exhaust gas.
Is provided. Further, the catalyst device 46 is provided with a catalyst bed temperature sensor 48 for detecting the internal temperature thereof.

The igniter 50 shown in FIG. 4 shuts off the current supplied to the primary winding of the ignition coil 51 installed above it based on the drive signal supplied from the electronic control unit (ECU) 60. . As a result, the ignition coil 5
In the secondary winding of No. 1, in synchronization with the drive signal of the ECU 60,
High-voltage back electromotive force is generated. Then, the high voltage signal thus generated in the ignition coil 51 is supplied to the distributor 52 as an ignition signal.

Further, the distributor 52 operates in synchronization with a crankshaft (not shown), and the ignition coil 5
The ignition signal supplied from No. 1 is distributed to the ignition plug 34 of a specific cylinder according to its rotation angle. Therefore, the ignition signal generated by the ignition coil 51 is supplied only to the ignition plug 34 of the cylinder to be ignited according to the crank angle of the internal combustion engine 10.

By the way, in the distributor 52,
A cylinder discrimination sensor 54 that generates a reference position detection signal of the crankshaft, and an internal combustion engine rotation speed signal of, for example, 30 ° C.
A rotation angle sensor 56 that is generated every time is provided. Then, the ECU 60, based on the cylinder discrimination signal ignition signal and the rotation angle signal supplied from these, outputs the igniter 5
A drive signal is issued at an appropriate timing of 0.

Further, as shown in FIG. 4, the internal combustion engine 10 of this embodiment is provided with an electric fan 58 as a cooling fan, and under a predetermined operating condition, that is, the cooling water temperature THW is 90.
The electric fan 58 is operated to cool the internal combustion engine 10 when the temperature becomes higher than 0 ° C or when the compressor pressure of the air conditioner becomes higher than 15 kg / cm ² , further, in the present embodiment, the vehicle speed is changed. A vehicle speed sensor 62 that generates a pulse signal of a corresponding cycle, a neutral switch 64 that detects that the transmission (including the case of an automatic transmission) is in a neutral state, an air conditioner (hereinafter referred to as an air conditioner)
An AC switch 66 that indicates the operating state of the brake pedal, a brake switch 67 that detects the operation status of the brake pedal, and an AC pressure sensor 68 that detects the compressor pressure of the air conditioner are connected to the ECU 60.

FIG. 5 is a block diagram showing the hardware configuration around the ECU 60. As shown in the figure, E
The CU 60 converts the output signals of the various sensors into predetermined digital signals and takes them in, an injector 20, the ISCV 26, an output port 70 for issuing control signals to the igniter 50, a CPU 72, a RAM 74, and a RO.
It is composed of an M76, a backup RAM 78, and a common bus 80 that connects them so that they can communicate with each other.

Here, in the transient knock suppression control system of the present embodiment, when the internal combustion engine 10 is in a state where transient knock is likely to occur, the ignition timing is retarded during idling or the idling speed is increased. It is characterized in that the generation of the fuel is suppressed by rotating it or by reducing the fuel increase correction executed at the time of acceleration for a predetermined period. Specifically, the CPU 72 is stored in the ROM 76. The above functions are realized by executing a predetermined process according to a program.

FIG. 6 shows a flowchart of an example of an ignition timing retarding routine executed by the CPU 76 to realize the above function. When this routine starts, first step 1
At 00, it is checked whether the idle state flag XIDL is "1".

This XIDL is a flag which is set to "1" when the idle switch 22 is turned on, and when XIDL = 1 is not established, that is, when the internal combustion engine is not in the idle state, go to step 101. Then, the ignition timing is calculated based on the load of the internal combustion engine and the engine speed.

On the other hand, in step 100, the XID
If it is determined that L = 1 holds, the process proceeds to step 102. Step 102 is a step of determining whether an ignition timing retard determination flag XABSEIDL, which will be described later, is "1". Here, XABSEIDL is a flag that is set to "1" when it is detected that the internal combustion engine 10 is likely to cause a transient knock based on the intake air temperature, the cooling water temperature, etc., and when XABSEIDL = 1 is established. If determined, step 104 is executed thereafter.

In step 104, the ignition timing in the idle state of the internal combustion engine 10 is set to 10 ° CA as compared with the normal time.
This is the step to set the retarded angle. Here, the ignition timing is retarded in this step because when the ignition timing is retarded at the time of idling, the temperature inside the combustion chamber 36 as a whole rises as the combustion speed of the fuel in the combustion chamber 36 decreases. This is because it is possible to suppress the above, and it is effective in preventing transient knock.

On the other hand, when it is determined in step 102 that XABSEIDL = 1 is not established, the routine proceeds to step 106, where the ignition timing in the normal idle state is set and the processing of this time is ended.

That is, this routine realizes the transient knock that occurs when the internal combustion engine 10 shifts from the idle state to the acceleration state by suppressing the temperature rise in the combustion chamber 36 in the idle state as described above. If the internal combustion engine 10 is not in the idle state, it is not necessary to change the setting of the ignition timing, and the ignition timing retard control is accompanied by the deterioration of the fuel consumption characteristic due to the decrease of the combustion pressure in the explosion process, so that the transient knock is likely to occur. Otherwise, there is no need to dare to do it.

Therefore, according to the transient knock suppression control system of the present embodiment, the temperature rise in the combustion chamber 36 can be prevented by retarding the ignition timing at the time of idling only when absolutely necessary.
Fuel efficiency characteristics will not be unduly deteriorated to prevent transient knock.

Further, when it is detected that the internal combustion engine 10 is apt to cause a transient knock, before the acceleration request is generated from the idle state and the intake air amount rapidly increases,
The inside of the combustion chamber 36 can be set to a relatively low temperature in advance, and a situation in which transient knock is unlikely to occur can be formed.

Further, since the ignition timing is retarded to prevent the transient knock only in the idle state that does not affect the running characteristics of the vehicle, the output of the internal combustion engine 10 is reduced due to the retard of the ignition timing. Therefore, transient knock can be suppressed while maintaining appropriate traveling characteristics without adversely affecting the vehicle's movement characteristics.

As described above, according to the transient knock suppression control system of the present embodiment, the transient knock during acceleration of the internal combustion engine can be reliably performed without unduly deteriorating the fuel consumption characteristic and the vehicle motion characteristic. Can be prevented.

FIG. 7 is a flow chart of an example of the ignition timing retard determination routine executed by the ECU 60 to set the above-mentioned XABSEIDL flag.

That is, when this routine is started, first, at step 200, it is judged if the intake air temperature THA is 50 ° C. or higher. Specifically, the output signal of the intake air temperature sensor 16 is read, the intake air temperature THA is calculated based on the signal value, and it is further determined whether THA ≧ 50 ° C. is satisfied.

Here, THA ≧ 50 ° C. occurs when the temperature around the intake air 12 and around the air intake of the intake passage 12 is high, and in the internal combustion engine 10 mounted on the vehicle, the engine room This state is formed when an idle state in which no flow velocity is generated continues for a relatively long period of time.

When such a condition is satisfied, the temperature of the combustion chamber 36 becomes relatively high because the air supplied to the internal combustion engine 10 is high, and the internal combustion engine 10 itself is sufficiently warmed up. If so, a situation in which a transient knock is likely to occur is formed.

Therefore, in this routine, if it is determined that the condition is satisfied in step 200, the process proceeds to step 202 and it is determined whether the cooling water temperature THW is 85 ° C. or higher based on the detection value of the water temperature sensor 32. Determine, T
If HW ≧ 85 ° C. is satisfied, the routine proceeds to step 204, where XABSEIDL is set to “1” and the processing is ended.

On the other hand, in step 200 above, THA
When it is determined that ≧ 50 ° C. is not satisfied, or the condition of the above step 200 is satisfied, the above step 2 is performed.
If it is determined that THA ≧ 85 ° C. is not established in 02, it is determined that the temperature in the combustion chamber 36 has not risen to the extent that transient knock occurs, and then Step 2
It was decided to proceed to 06 and reset XABSEIDL to end the processing.

Therefore, when the ECU 60 sets / resets XABSEIDL in accordance with this routine, the ignition timing is not retarded until the internal combustion engine 10 is sufficiently warmed up, and the internal combustion engine 10 is not sufficiently retarded. Even in the warmed-up state, the ignition timing is not retarded during steady running in which the entire engine room is appropriately cooled, and ignition timing retard control is performed under unnecessary circumstances to suppress transient knock. Never executed.

The ignition timing retard control during idling, which is realized by the routines shown in FIGS. 6 and 7, is performed by delaying the ignition timing during idling (step 104) or by using the normal ignition timing. The timing (step 106) is selected according to the situation of the internal combustion engine 10. For example, as shown in FIG. 8, the cooling water temperature THW,
Alternatively, a configuration may be adopted in which a retard amount map with the intake air temperature THA as a parameter is set, and the retard amounts corresponding to THW and THA are set according to individual situations.

In this case, the delay amount map shown in FIG.
The higher the temperature of HW and the higher the temperature of THA,
The retard amount is set to have a large value, and as the transient knock is more likely to occur, the larger retard amount is set, and the transient knock is effectively suppressed.

FIG. 9 shows a flowchart of a second example other than the ignition timing retarding routine executed by the ECU 60. still,
In the figure, steps for performing the same processes as those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

That is, in the routine shown in FIG. 9, when XIDL = 1 is established in step 300, the flag XNSW indicating that the neutral switch is on is cleared to "0" in step 302, that is, the shift position. As to determine whether a position other than neutral is selected.

When the vehicle shifts from the idle state to the acceleration state, one of the shift positions must be selected prior to that, and as a result, XNSW = "0" should be established. Therefore, while this condition is not established, This is to further eliminate waste by not performing the retard control.

Therefore, in this routine, the above step 3 is performed.
If the condition of 02 is not satisfied, then the routine proceeds to step 310, the normal ignition timing is set and the process is terminated, and if the condition of the above step 302 is satisfied, the step 30 is performed.
In step 4, XABSEIDL is determined.

In step 304, XABSE
If it is determined that IDL = 1 holds, then in step 306, a flag X indicating the state of the brake switch 67 is displayed.
The state of SWB is determined.

As in the case of the neutral switch 64, the brake switch 67 is always turned off at the time of shifting to acceleration. Therefore, the ignition timing is delayed while the brake switch 67 is on, that is, XSWB = 0 is not established. This is because it is possible to eliminate waste as much as possible.

That is, in the case of a vehicle with an automatic transmission, when the shift lever is shifted from the N range to the drive range (D range, R range), the brake pedal is usually depressed. After that, the brake is turned off when the accelerator pedal is depressed to start the vehicle.Therefore, the state of retarding the ignition timing should be limited to just before the vehicle starts, while the ignition timing is controlled by simply looking at the state of the neutral switch. Therefore, waste can be further eliminated.

Therefore, in this routine, if XSWB = 0 is not established in step 306, the routine proceeds to step 310, where a normal ignition timing is set, and XS is set.
Only when WB = 0 is satisfied, the routine proceeds to step 308, where retard control of the ignition timing at the idle time is performed.

Therefore, when the ECU 60 executes the ignition timing retarding routine shown in FIG. 9, it is possible to further reduce the deterioration of the fuel consumption characteristic of the internal combustion engine 10 due to the suppression of the transient knock.

In the above embodiment, step 100 in FIG. 6 and step 300 in FIG. 9 are performed by the above-mentioned idle state detecting means M1 and steps 200 and 2 in FIG.
02 to the intake air temperature detecting means M2 and the cooling water temperature detecting means M3, the steps 104 and 106 in FIG. 6 and the ignition timing calculating means M4 to steps 308 and 310 in FIG. 9, and the igniter 50 and the distributor. 52 corresponds to the ignition timing control means M5 described above.

As described above, the region where knocking occurs in the internal combustion engine varies depending on the ignition timing, but the throttle valve 18 is fully opened (hereinafter, this situation is referred to as WOT) and the engine speed and knocking When the relation between the ignition timing and the ignition timing is measured, a characteristic curve is generally obtained as shown in FIG.

That is, as shown in FIG. 10, the region where knocking occurs in the internal combustion engine shifts to a higher advance side as the engine speed increases, and the engine speed increases for the same advance value. It turns out that it is more advantageous for suppressing knocking.

On the other hand, FIG. 11 shows a knock signal (FIG. 11 (A)) representing a transient knock occurrence timing in an internal combustion engine combined with an automatic transmission, a change in intake air amount during acceleration (FIG. 11 (B)), and acceleration. 11 is a time chart showing changes in engine speed (FIG. 11 (C)) at each time. In FIG. 11, transient knock occurs (time t _{3 in the} figure), and after acceleration starts (in the figure). , Time t ₁ ) The intake air amount suddenly increases (in the figure, at time t
₂ ) After that, it was detected before the engine speed increased.

That is, in order to suppress the transient knock that occurs when the internal combustion engine in the idle state is shifted to the acceleration state, it is necessary to improve the knocking resistance of the internal combustion engine at the idle speed. To improve its knock resistance in advance of the combustion chamber 36 prior to the acceleration request.
This was achieved by maintaining a relatively low temperature inside.

In this case, it is clear from the characteristic curve shown in FIG. 10 that increasing the idling speed is effective as a method for increasing the knock resistance in the idling state. If the number is increased, the same effect as in the case of the ignition timing retard control described above can be obtained.

FIG. 12 shows a flow chart of an example of an idle speed setting routine executed by the ECU 60 in order to suppress the transient knock according to the above principle. In the figure, the same steps as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.

As described above, the transient knock in the internal combustion engine 10 is particularly likely to occur when the ambient temperature is high. The ambient temperature of the internal combustion engine 10 is likely to become particularly high when the air conditioner mounted on the vehicle operates and the heat generated by heat exchange is dissipated into the engine room.

For this reason, in this routine, the operation of the air conditioner is grasped as a situation in which transient knock suppression is required, and the idle speed NT _ACON under such situation is controlled as a transient knock suppression means.

That is, in the routine shown in FIG. 12, in step 400, it is judged whether THA ≧ 50 ° C. is satisfied. In step 402, THW ≧ 85 ° C.
Is determined.

If the condition is satisfied in any of these steps, it is determined that the internal combustion engine 10 is in a state where transient knock is likely to occur, and thereafter, in step 404, NT _ACON is set to 650 rpm and the process is ended. .

On the other hand, if either of the conditions of step 400 or 402 is not satisfied, it is judged that the internal combustion engine 10 is not in a situation where transient knock is likely to occur, and thereafter, at step 406, NT _ACON is set to 550 rpm. Then, the process ends.

The NT set in this way
_ACON is realized by the ISCV 26 changing the valve open state based on a control signal issued by the ECU 60 according to an idle speed feedback routine as shown in FIG.

That is, when the routine shown in FIG. 13 is started, first, at step 410, the target idle speed (550 rpm or 650 rpm, set as described above) is set.
Hereinafter, simply referred to as the target rotation speed) is read.

Next, in step 412, based on the output pulses of the rotation angle sensor 5 6, the actual engine speed (hereinafter, simply referred to as the actual rotational speed) read. And step 41
In step 4, the target rotation speed is compared with the actual rotation speed. If target rotation speed> actual rotation speed is satisfied, the process proceeds to step 416 and the ISC
The opening degree of V26 is increased, and when the target rotation speed> the actual rotation speed is not satisfied, the routine proceeds to step 418, where the opening degree of ISCV26 is decreased and the processing is ended.

In this embodiment, as described above, the IS
Since the CV 26 is driven by the step motor, the increasing / decreasing opening of the ISCV 26 can be easily and accurately controlled in the steps 416 and 418.

As a result, the temperature of the internal combustion engine 10 itself, that is, THW, and the ambient temperature of the internal combustion engine 10, that is, T
When both HAs are at high temperature, NT _ACON is set to relatively high rotation speed, and it is possible to secure appropriate knock resistance despite the situation that the ambient temperature easily rises due to the operation of the air conditioner. On the other hand, when the internal combustion engine 10 is not in a situation where transient knock is inherently likely to occur, on the other hand, a low idle speed that is advantageous in terms of fuel consumption characteristics is realized.

Therefore, even when the ECU 60 executes this routine, as in the case where the routines shown in FIGS. 6 to 9 are executed, it is possible to maintain both high fuel efficiency and effective suppression of transient knock. You can

14 to 16 are flowcharts of another example of the idle speed setting routine which is executed by the ECU to control the idle speed NT _ACON as appropriate to suppress transient knock. In the figure, the same steps as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.

That is, in this embodiment, the rouch shown in FIG. 14 is used.
NT at_ACONIdol prior to making settings
The rotation speed setting judgment flag XATRNA is specially determined.
If the XATRNA = 1, the
NT at step 502_{AC ON}650 rpm is XAT
If RNA = 0, then in step 504 NT
_ACONIs set to 550 rpm.

15 and 16 show a subroutine for setting / resetting XATRNA.

That is, in step 600 in FIG. 15, XATRNA indicates that the idle state duration timer CID
It is set to "1" when L is detected to have reached 180 seconds and then step 602 is executed. Then, in the above step 600, CIDL ≧ 180se
If it is determined that c is not satisfied, then it is reset in step 604.

The idle state duration timer CIDL is
It is counted up or reset by the 1s count routine shown in FIG. This 1s count routine is a timed interrupt routine that is executed every 1 second, and THW ≧ 85 ° C. at step 700 after starting.
Determine the applicability of.

When THW ≧ 85 ° C. is satisfied, that is, when it is determined that the internal combustion engine 10 is sufficiently warmed up, the routine proceeds to step 702, where the output signal SPD of the vehicle speed sensor 62 does not reach 3 km / h. It is determined whether the vehicle is showing a slow speed or a stopped state.

When this condition is also satisfied,
The flow velocity in the engine room is weak, and it is determined that the internal combustion engine 10 is likely to cause a transient knock, and the routine proceeds to step 704.

At step 704, it is judged whether the internal combustion engine 10 is in the idle state or not based on the value of XIDL.
Then, XIDL = 1 holds, that is, the internal combustion engine 1
When 0 is determined to be in the idle state, it is determined that the internal combustion engine 10 gradually shifts to a state in which transient knock is likely to occur, the process proceeds to step 706, CIDL is incremented, and the process ends.

In step 704, the XID
When L = 1 is not established, that is, when it is determined that the internal combustion engine 10 is in the low speed state but not in the idle state, it is determined that the transient knock resistance does not change, the process proceeds to step 708, and the CIDL is held. Then, the processing of this time is ended.

On the other hand, if it is determined in step 700 that THW ≧ 85 ° C. is not satisfied, and if it is determined in step 702 that SPD <3 km / h is not satisfied, the internal combustion engine 10 respectively. Determines that the temperature has not risen to a state in which a transient knock is generated, or that cooling around the internal combustion engine 10 is being promoted as the vehicle travels, and then the process proceeds to step 710 and the CIDL is set. Reset and finish this process.

Therefore, the CIDL of the present embodiment is incremented only when the internal combustion engine 10 continuously maintains a low speed or a stopped state of less than 3 km / h and is appropriately idled. And the accumulated time in the idle state is 18
Only when the time reaches 0 sec, XATRNA is set to "1", and the idle speed NT _ACON is increased.

Therefore, as compared with the case of judging the transient knock resistance of the internal combustion engine 10 based on THW and THA as in the embodiment shown in FIG. 12, the running state of the vehicle is reflected in more detail in the judgment. Therefore, it is possible to realize the transient knock suppression control without wastefully increasing the idle speed.

By the way, in the embodiment shown in FIGS. 12 to 16, the environment of the internal combustion engine 10 is particularly disadvantageous in terms of transient knock when the air conditioner operates, so control is limited to the idle speed when the air conditioner is operating. However, the configuration is not limited to this, and control may be performed to increase the idle speed at a high temperature when transient knock is likely to occur even when the air conditioner is not operating.

When the ECU 60 executes the routines shown in FIGS. 12 to 16, the step 4 in FIG.
04, 406 and the steps 502, 504 in FIG. 14 realize the above-described idle speed calculation means M6, and the ISCV 26 realizes the above-mentioned idle speed control means M.
7 will be realized.

By the way, the ECU 60 of the present embodiment, when it is detected that the internal combustion engine 10 is in the accelerating state based on the sensor outputs of the intake pressure sensor 14, the idle switch 22, etc., corrects the acceleration of the fuel, and It has a function of performing acceleration asynchronous injection correction (hereinafter, when these are collectively referred to, simply referred to as increase correction).

Here, the fuel acceleration increase correction is a fuel increase correction in which an appropriate fuel increase amount calculated based on the operating state of the internal combustion engine at the time of acceleration is added to the normal fuel injection amount to inject. The asynchronous injection is a fuel amount increase correction that performs a predetermined amount of fuel injection regardless of the rotation angle of each cylinder, that is, asynchronously with the intake stroke of each cylinder, when an acceleration request is generated in the internal combustion engine.

That is, in the internal combustion engine having the function of electronically controlling the fuel injection amount, the basic fuel injection amount is calculated based on the load of the internal combustion engine, the engine speed, etc., and the fuel injection is performed based on the calculation result. During the acceleration transition, the basic injection amount may be insufficient with respect to the actually required fuel injection amount due to the response delay of the load detecting sensor, the calculation delay accompanying the calculation of the fuel injection amount, and the like.

On the other hand, when the above-described increase correction is performed to increase the fuel injection amount immediately after the acceleration request occurs, the fuel injection amount during the acceleration transition can be sufficiently secured, It is possible to obtain excellent acceleration characteristics.

However, it is empirically known that, when the increase correction is performed during acceleration, a situation where transient knock is likely to occur in the initial stage of acceleration is formed. That is, the margin for knocking in the internal combustion engine is generally the smallest in the vicinity of the theoretical air-fuel ratio, and a higher margin can be obtained as the distance from the stoichiometric air-fuel ratio increases.

On the other hand, when the acceleration increase correction is performed as described above, the air-fuel ratio of the air-fuel mixture passes near the stoichiometric air-fuel ratio where knocking is most likely to occur in the initial stage of acceleration. For this reason, when the internal combustion engine accelerates in a situation where the cooling water temperature of the internal combustion engine is high and the intake air temperature is high, a situation is created in which knocking is particularly likely to occur at the initial stage of acceleration.

Further, in the internal combustion engine 10 of the present embodiment, when the cooling water temperature THW becomes 90 ° C. or higher, or
As described above, the electric fan 58 that operates when the sensor output of the C pressure sensor 68, that is, the compressor pressure of the air conditioner becomes 15 kg / cm ² or more is provided. When the heat of the engine 10 is dissipated, the ambient temperature in the engine room then rises as a whole.

When the atmospheric temperature in the engine room as a whole rises in this way, the temperature of the intake air taken in through the air filter arranged in the engine room, that is, the intake air temperature THA rises. Therefore, the internal combustion engine 10 is in a state in which transient knock is more likely to occur.

Therefore, in this embodiment, both THW and THA are equal to or higher than a predetermined temperature, and the electric fan 58 is used.
When the operating condition of is satisfied, the fuel increase correction at the initial stage of acceleration is reduced by a predetermined period to suppress the transient knock in such a situation while ensuring good acceleration characteristics.

In this embodiment, the electric fan 58 is used.
When the operating condition of is satisfied, the electric fan 58 is operated and a process of increasing the idle speed (hereinafter referred to as idle up) is performed. This is because the cooling water temperature is lowered and the operating state of the internal combustion engine is stabilized by idling up.

In this case, THW ≧ 90 ° C.
In addition to the above, the air conditioner compressor pressure ≧
Even when 15 kg / cm ² is established, the electric fan 58 is operated and the idle-up is performed because the load of the internal combustion engine 10 is large and it is necessary to prevent the decrease in the rotational speed under such a condition. Is.

17 to 21 are flowcharts of routines executed by the ECU 60 to satisfy the above functions. The specific contents will be described below. FIG. 17
FIG. 6 is a flow chart of an acceleration increase correction routine for reducing the acceleration increase when it is determined that a transient knock is likely to occur. Further, FIG. 18 is a flowchart of a condition determination routine for determining whether or not to execute reduction correction of acceleration increase, and FIG. 19 is a flowchart of an initialization routine executed prior to execution of the condition determination routine.
20 is a flowchart of a flag processing routine that sets flags used in the condition determination routine.

That is, when the operation of the ECU 60 is started, the initialization routine shown in FIG. 19 is started. Then, in step 800, the flag XCFM is set to "0".
Is set, and then in step 802, the upper limit value FF (255 ms) is set in the 1 ms counter CKNK, and this processing is ended.

The flag XCFM is a flag for storing the state of the electric fan 58 when the operation of the electric fan 58 is started as described later, and CKNK is counted up toward the upper limit value FF every 1 ms. Counter.

When the initialization process is completed in this way,
The acceleration amount increase correction routine shown in FIG. 17 and the condition determination routine shown in FIG. 18 are started.

Here, in the acceleration increase correction routine shown in FIG. 17, CKNK ≦ 2 for the above-mentioned counter CKNK.
This is a routine for correcting the amount of acceleration increase by decreasing when 00 ms is satisfied. In this routine, the rotation angle sensor 56 detects a predetermined rotation angle before the fuel injection timing of each cylinder, so that, for example, in a four-cylinder internal combustion engine, 180 ° C.
It is activated every A.

In this routine, in step 900, for example, the intake pressure sensor 1 which is AD-converted every 1 to 2 ms.
The difference DLPM between the measured value PM of No. 4 and the intake pressure PM0 detected last time (that is, before 180 ° CA) is calculated as a characteristic value representing a transient pressure change. The measurement value PM of the intake pressure sensor 14 is smoothed by a filter circuit (not shown) or a process on software.

In step 902, the cooling water temperature contribution K1TH W in the weighting coefficient K1 when the fuel increase amount by the pressure change DLPM is detected is calculated. This K1 THW
Is a value that changes according to the cooling water temperature THW, and
K1TH for THW is stored in ROM76 of CU60.
A map showing the value of W is stored. Then, the THW measured by the water temperature sensor 32 is referred to the map to calculate the corresponding K1THW.

At step 904, the contribution K1NE of the engine speed in the weighting coefficient K1 when calculating the fuel increase amount by the pressure change DLPM is calculated. This K1NE
Is a value that changes according to the engine speed NE, and
The ROM 76 of 60 stores a map showing the value of K1NE for NE. Then, the map is referred to by the actual measurement value of the NE detected below the pulse signal output from the cylinder discrimination sensor 54, and the corresponding K1NE
Is calculated.

In step 906, the above step 90
K1THW and K calculated in 2 and 904, respectively
The sum of 1NE is calculated as the weighting coefficient K1 for calculating the fuel increase amount due to the pressure change.

Next, at step 908, the pressure change DL
The cooling water temperature contribution K2TH W in the weighting coefficient K2 when calculating the fuel increase amount by the time integral term of PM is calculated. The value of K2THW is a value that changes in accordance with the cooling water temperature THW, and is calculated by referring to the actually stored THW of the map stored in the ROM 74, similar to the above K1THW.

At step 910, the weighting coefficient K for calculating the fuel increase amount by the time integral term of the pressure change DLPM.
The contribution K2NE of the engine speed at 2 is calculated.
This K1NE is also a value that changes according to the engine speed NE, and is calculated by referring to the map stored in the ROM 74 with the measured value of NE, as in the case of K1NE.

In step 912, the K2TH calculated in steps 908 and 910, respectively, is calculated.
The product of W and K2NE is calculated as the weighting coefficient K2 for calculating the fuel increase amount by the integral term of the pressure change DLPM.

At step 914, the pressure difference integrated value DLP
M_iBut DLPM + K3 × DLPM _i-1Calculated by
Be done. Here, K3 is the integral value up to the previous processing,
Is a weighting coefficient of about 0.9.

The above equation physically has the meaning of the total sum of pressure changes (that is, intake air amount changes) up to the previous time. That is, in FIG. 22A, the solid line shows the actual change of the intake pipe pressure in the transient state, and the broken line shows the intake pipe pressure PM after the anneal.

Here, in this routine, the fuel injection amount is calculated based on the blunted intake pipe pressure value. However, if the fuel injection amount is calculated based on the blunted value, it is transiently empty. The fuel ratio will be rough. Therefore, it is necessary to correct the difference between the actual intake pipe pressure and the smoothed value, and specifically, it is necessary to correct the difference as shown in FIG.

In this embodiment, the addition method is used to increase the amount and to correct it. That is, the change amount of the intake pipe pressure is calculated, and thereby the correction amount to be added to the basic injection amount is calculated.

In FIG. 22C, DLPM is
The difference in intake pipe pressure from the previous time is shown. This value is the previous injection
This corresponds to an increase in the injection amount between this injection and this injection. On the other hand, D
LPM_iCorresponds to the sum of the fuel injection amounts up to the previous time.
Therefore, DLPM, DLPM _iCorresponding to each of the
The sum of products obtained by multiplying only the coefficients K1 and K2, “K1 × DL
PM + K2 × DLPM_i"Before the transition
Total pressure change. Then, the fuel injection amount from the intake pipe pressure
If the conversion coefficient to C is C, then “C × (K1 × DLPM +
K2 x DLPM_i"Is the transient increase value.

By the way, as described above, when the internal combustion engine is in a state where transient knock is likely to occur, the transient knock is likely to occur temporarily due to an increase in fuel amount during acceleration. Therefore, in the present embodiment, when the internal combustion engine is in a state where transient knock is likely to occur, the transient increase value during acceleration is reduced, and specifically, the following steps 916 to 922 are executed. By doing so, the above function is realized.

That is, at step 916, it is determined whether or not CKNK ≦ 200 ms holds for the counter CKNK described above. When CKNK ≦ 200 ms is established, the routine proceeds to step 918, where the correction coefficient tK
Set 0.25 to KNK, while CKNK ≤ 200ms
If is not established, the routine proceeds to step 920, where the correction coefficient tKKNK is set to 1.0.

Then, in step 922, "C × (K1 × DLPM + K2) calculated as a basic transient increase value.
× DLPM _i ″, the correction coefficient tKK calculated as described above
NK is multiplied to calculate the final acceleration increase TPAEW.

That is, in this embodiment, CKNK ≦
When 200 ms is satisfied, the acceleration increase TPAEW is reduced by 1/4 as compared with the case where this condition is not satisfied.

Since FF is set as the initial value in the counter CKNK as described above, the condition of step 916 is not satisfied unless the value is reset as described later, and the correction coefficient tKKNK is set to 1 .0 will be set.

By the way, CKNK in which FF is set as the initial value is reset when it is determined in the condition determination routine shown in FIG. 18 that a predetermined execution condition is satisfied.

That is, when the routine shown in FIG. 18 is started, first in step 1000, CKNK ≧ 200.
Determine the validity of ms. Then, if CKNK ≧ 200 ms is established, the routine proceeds to step 1002. On the other hand, if the above conditions are not established, the routine of this time is ended without performing any processing thereafter.

In this embodiment, since FF is set as the initial value in CKNK, the above condition is satisfied unless the value is reset. Also, CKN
If K ≧ 200 ms is not established, no further processing is performed in order to prevent the reset CKNK from being repeatedly reset while reaching 200 ms.

In step 1002, the intake air temperature THA is 3
Determine whether the temperature is 0 ° C or higher. Also, step 1004
Then, it is determined whether the cooling water temperature THW is 85 ° C. or higher. This is to determine whether or not the internal combustion engine 10 is in a state where transient knock is likely to occur, based on the feasibility of these.

Then, the above steps 1002 and 10
If the conditions of 04 are both satisfied, it is determined that the transient knock is likely to occur, and the process proceeds to step 1006. On the other hand, if any of the conditions is not satisfied, the process of this time is terminated without performing any subsequent process.

Step 1006 is "0" at the time of initialization.
This is a step for checking whether or not "1" is set in the XCFM flag that has been set. This XCFM flag is an electric fan 58 operation memory flag set by the flag processing routine shown in FIG. 20, and when the electric fan 58 operates, a transient knock is more likely to occur as the intake air temperature THA rises. This is the basis of the determination in determining whether or not a transient knock is likely to occur.

That is, in the internal combustion engine 10 of this embodiment, the electric fan 5 is operated when THW is 90 ° C. or higher or the compressor pressure of the air conditioner is 15 kg / cm ² or higher.
As described above, 8 is activated and idle-up is performed, but during the execution of such processing, the flag XCF is set to "1" to indicate the activated state.

On the other hand, in the routine shown in FIG. 20, first, in step 1100, XFC = "1".
If XFC = “1” is satisfied, the process proceeds to step 1102 and the flag XCF is determined.
The M is set to "1" and the process ends.

That is, after the ECU 61 starts to start,
Before starting the operation of the electric fan 58, XFC
Since M is "0", the condition of the above step 1006 is not satisfied. After that, once the operating condition of the electric fan 58 is satisfied, XFCM is kept at "1" and the condition of the above step 1006 is always satisfied. Become.

In the above determination, the flag XCF indicating the operating state of the electric fan 58 is not directly used, but the storage flag XCFM is used because the XCF returns to "0" immediately after the electric fan 58 is stopped. This is because it takes a certain amount of time for the intake air temperature that has risen due to the operation of the electric fan 58 to drop, and that the XCF and the likelihood of transient knock do not necessarily match.

If it is determined at step 1006 that the above condition is satisfied, the routine proceeds to step 1008, at which it is determined whether or not the vehicle speed SPD is 15 km / h or less. When SPD ≦ 15 km / h is not established, the internal combustion engine 10 is cooled by the flow velocity during traveling, and the intake air temperature THA decreases, so it is determined that transient knocking is unlikely to occur, and no processing is performed at this time. The process ends.

On the other hand, if SPD ≦ 15 km / h is satisfied, the flag XTRN is set to “1” in step 1010.
Is set, and if XTRN = 1 is satisfied, the process proceeds to step 1012, and if XTRN = 1 is not satisfied, the current process is ended.

XTRN is a flag which becomes "1" when the internal combustion engine 10 is in a transitional period associated with acceleration. Specifically, the change amount ΔPM of the digital conversion value PMAD of the intake pipe pressure PM is PM. Judgment value LVL set as a function
If it is equal to or greater than TRN, "1" is set.

Here, PM is a value varying from about 300 mmHg to about 760 mmHg. For example, LVLYRN = 60 mmHg for PM = 600 mmHg and LVLYRN = 120 mmHg for PM = 759 mmHg. That is, when PM increases during acceleration, the determination value LVLYRN also increases accordingly.
During normal acceleration, XT only once for each acceleration operation
“1” is set in RN.

At step 1012, it is judged if the engine speed NE is less than 3000 rpm.
Step 1014 only when <3000 rpm is satisfied
Go to. This is because the transient knock does not become a problem in the high rotation region where NE is 3000 rpm or more.

In step 1014, PMAD ≧ 600 mm
This is a step of determining whether or not Hg is established, and step 1016 is subsequently executed only when the above condition is established. Since transient knock is a phenomenon that occurs when the throttle is opened widely, PMAD ≧ 600 mmHg
This is because the region where is not satisfied can be excluded from the situation in which transient knock is likely to occur.

Further, step 1016 is a step of judging whether the value of the acceleration increase tTPAEW calculated in another subroutine is a positive value. This routine is a routine for suppressing transient knock by reducing the acceleration increase amount added to the normal injection amount during acceleration of the internal combustion engine 10, and is based on the assumption that the acceleration increase amount tTPAEW is a positive value. Is.

Then, the above steps 1000 to 1018
Only when all the conditions are satisfied, in step 1018, the process of resetting CKNK is performed, and when the condition is not satisfied in any step, any process is performed on the CKNK that is counted up every 1 ms. Without this, the processing of this time is ended.

As a result, after the ECU 60 is started, the upper limit value FF is held in CKNK until all the conditions of steps 1000 to 1018 are satisfied. Therefore, in the acceleration increase correction routine shown in FIG. , 1.0 is always selected as the correction coefficient tKKNK, and in step 922, the acceleration increase TPAEW which is not decreased is calculated.

Then, the above steps 1000 to 1018
If all of the conditions are satisfied, then 0.25 is selected as the correction coefficient tKKNK in the acceleration increase correction routine shown in FIG.
In 22, the acceleration increase amount T corrected to be reduced to 1/4 of the normal time
PAEW will be calculated.

In the routine shown in FIG. 17, when the processing of step 922 is completed, the next step 9
At 24, the basic fuel injection amount TP is calculated. As is well known, the basic fuel injection amount is calculated based on the intake pipe pressure and the engine speed to realize the stoichiometric air-fuel ratio.

The ROM 76 of the ECU 60 stores a map of the basic fuel injection amount with respect to the combination of the intake pipe pressure and the engine speed. By interpolation, the basic fuel injection amount with respect to the intake pipe pressure and the engine speed is stored. Is calculated.

Then, in step 926, the final fuel injection amount TAU is calculated as "TAU = (TP + TPAEW) ×
It is calculated by α + β ″. Here, α and β are correction coefficients that collectively represent various correction amounts adopted when calculating the fuel injection amount of the internal combustion engine.

Further, at step 928, the fuel injection signal is formed. , This fuel injection signal is the same as in step 9 above.
The fuel injection amount calculated in step 26 is formed so as to obtain the fuel injection amount, and the fuel injection amount is output to the injector 20.

Then, in step 930, the current P
The M value is moved to PM0, then in step 932, the current DLPM _i is set to DLPM _i-1 for the next processing, and the processing of this time is ended.

As described above, the internal combustion engine 10 of this embodiment performs the acceleration boost injection and the acceleration asynchronous injection as the fuel boost correction during acceleration. Here, the acceleration asynchronous injection is also an unfavorable correction from the viewpoint of suppressing transient knock, like the acceleration boost injection in that the fuel is enriched during acceleration.

Therefore, in this embodiment, the internal combustion engine 1
When 0 is in a situation where a transient knock is likely to occur, the reduction correction is also performed for the acceleration asynchronous injection.

FIG. 21 shows an ECU for satisfying such a function.
6 is a flowchart of an asynchronous injection amount correction routine executed by 60, and the specific processing contents will be described below. Note that in FIG. 21, steps that perform the same processing as in FIG. 18 are assigned the same reference numerals and explanations thereof are omitted or simplified.

That is, in the routine shown in FIG. 21, it is determined in step 1200 whether XTRN = 1 is satisfied, that is, whether the internal combustion engine is accelerating, and in step 1202 it is determined whether THA ≧ 30 ° C. is satisfied. , In step 1204, it is judged whether THW ≧ 85 ° C., and in step 1206 SPD <15 km / h.
Is determined, and XC is determined in step 1208.
This is a routine for judging the feasibility of FM = 1, executing the processing of step 1210 when all of them are established, and executing the processing of step 1212 when any of the conditions is not established and ending the processing.

Here, the above steps 1200 to 1208
Similar to the routine shown in FIG. 18, the condition of is a condition for determining whether or not the internal combustion engine 10 is likely to cause a transient knock.

Then, step 1210 which is executed when all of these are established is a step of setting the injection time tTAUASY of the acceleration asynchronous injection to 0.5 ms,
On the other hand, the step 1212 executed when either of the conditions is not satisfied is the injection time tTAUASY of the acceleration asynchronous injection.
Is set to 2.0 ms.

Therefore, when this routine is executed by the ECU 60, if the internal combustion engine 10 is not in a situation where transient knock is likely to occur, normal acceleration asynchronous injection (2 ms) ensures good acceleration characteristics, and transient knock occurs. In a situation where it is likely to occur, the acceleration asynchronous injection in which transient knock is unlikely to occur is executed.

By the way, in the present embodiment, the acceleration asynchronous injection amount is set to a constant value, but the degree of acceleration (eg ΔP
M), it may be calculated according to the state of the internal combustion engine (for example, the cooling water temperature THW). Even in this case, when the transient knock as described above is likely to occur, a constant amount is calculated from the calculated asynchronous injection amount. The amount may be reduced, or the calculated asynchronous injection amount may be restricted so as not to exceed a certain amount (so-called guard processing), or the asynchronous injection amount may be prohibited in some cases.

23 and 24 respectively show the case where the above-described acceleration amount increase and the amount reduction correction control of the acceleration asynchronous injection are executed, and the case where the amount increase correction at the time of acceleration is executed without executing the correction control. FIG. 5 is a diagram showing a result of measuring a state of occurrence of transient knock with respect to.

23 and 24, the horizontal axis represents a test in which the automatic transmission is set to the D range and the accelerator pedal is depressed while the brake is depressed in the vehicle (hereinafter,
The number of cycles for which a stall test is performed is shown, the solid line in the figure indicates the fluctuation state of the cooling water temperature THW, and the broken line indicates the intake temperature THA
Change situation, the strength of knocking that the one-dot chain line occurred,
Shown respectively.

In this case, before THW ≧ 90 ° C. is satisfied and the electric fan 58 starts to operate, as shown in FIG.
24 and 27, knocking of "no knock" or "fine" level occurs at almost the same frequency, but the control of the present embodiment is executed in the region where the electric fan 58 starts to operate. In FIG. 22, “fine” or “small”
While the level knocking has only occurred, in FIG.
Frequent "medium" or "large" level knocking.

Further, FIG. 25 is a graph showing the results of measuring such tendency with different correction coefficients tKKNK, and showing the intensity distribution of knocking generated in the stall test.

In this case, FIG. 25 shows that the smaller the correction coefficient, that is, the smaller the increase correction at the time of acceleration, the smaller the knocking intensity that occurs and the lower the frequency, which is adopted in this embodiment. To tKKN
According to K = 0.25, while maintaining good acceleration characteristics,
It is possible to effectively suppress the transient knock.

By the way, in this embodiment, the acceleration increase injection and the acceleration asynchronous injection are adopted as the increase correction during acceleration, and the decrease correction is performed for both of these corrections. However, the present invention is not limited to this. It is also possible to apply a configuration in which only one of them is adopted as the increase correction at the time of acceleration, or both increase corrections are adopted and the decrease correction is performed only in either one.

In the above embodiment, the electric fan 5 is used.
Step 1006 or 1 for storing the operating state of No. 8
Reference numeral 208 corresponds to the above-mentioned fan operating state detecting means M8, and the above steps 902 to 906 or 12 for appropriately calculating the correction amount at the time of acceleration in accordance with the ease of occurrence of transient knocking.
10, 1212 are the injection amount correction means for acceleration M9 described above.
And the correction amount reducing means M10.

[0167]

As described above, according to the first aspect of the present invention, when the internal combustion engine itself and its environment are in a state where transient knock is likely to occur in the idle state, prior to the generation of the acceleration request. The rise in the temperature of the combustion chamber inner wall in the idle state is suppressed.

Therefore, according to the transient knock suppression control device for an internal combustion engine according to the present invention, when the internal combustion engine and its environmental temperature are high when an actual request for acceleration occurs in the idle state, Also, the occurrence of transient knock can be effectively suppressed.

Further, according to the second aspect of the present invention, when a situation in which transient knock is likely to occur in the idle state is made, the idle speed is increased and a situation in which knocking is unlikely to occur is realized. Therefore, also in the transient knock suppression control device for an internal combustion engine according to the present invention, it is possible to effectively suppress the occurrence of transient knock, as in the case of the invention according to claim 1.

Further, according to the invention described in claim 3, when the internal combustion engine is in a predetermined high temperature state and the intake air temperature further rises with the operation of the cooling fan, a predetermined period after the acceleration is started. The fuel amount increase correction is performed with the amount reduced compared to the normal time. Therefore, according to the transient knock suppression control device for an internal combustion engine according to the present invention, it is possible to make the air-fuel ratio leaner only in a predetermined period in the initial stage of acceleration, while maintaining good acceleration characteristics, while effectively starting. , And transient knock during acceleration can be suppressed.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the invention according to claim 1.

FIG. 2 is a principle configuration diagram of the invention according to claim 2;

FIG. 3 is a block diagram showing the principle of the invention according to claim 3;

FIG. 4 is an overall configuration diagram of a transient knock suppression control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 5 is a block configuration diagram around an ECU of the transient knock suppression control device of the present embodiment.

FIG. 6 is a flowchart of an example of an ignition timing retarding routine executed by the ECU in the present embodiment.

FIG. 7 is a flowchart of an example of an ignition timing retard determination routine executed by an ECU in the present embodiment.

FIG. 8 is an example of a map referred to in an ignition timing retarding routine in the present embodiment.

FIG. 9 is a flowchart of another example of an ignition timing retarding routine executed by the ECU in the present embodiment.

FIG. 10 is a characteristic curve showing a relationship between an advance value that causes knocking in an internal combustion engine and an engine speed.

FIG. 11 is a time chart for explaining the timing of occurrence of transient knock of the internal combustion engine.

FIG. 12 is a flowchart of an example of an idle speed setting routine executed by the ECU in the present embodiment.

FIG. 13 is a flowchart of an example of an idle speed feedback control routine executed by an ECU in the present embodiment.

FIG. 14 is a flowchart of another example of an idle speed setting routine executed by the ECU in the present embodiment.

FIG. 15 is a flowchart of an example of an idle speed setting determination routine executed by the ECU in the present embodiment.

FIG. 16 is a flowchart of an example of an idle state duration time counting routine executed by the ECU in the present embodiment.

FIG. 17 is a flowchart of an example of an acceleration increase correction routine executed by the ECU in the present embodiment.

FIG. 18 is a flowchart of another example of the condition determination routine executed by the ECU in the present embodiment.

FIG. 19 is a flowchart of an example of an initialization routine executed by the ECU in the present embodiment.

FIG. 20 is a flowchart of an example of a flag processing routine executed by the ECU in the present embodiment.

FIG. 21 is a flowchart of an example of an asynchronous injection amount correction routine executed by the ECU in this embodiment.

FIG. 22 is a diagram for explaining a method of calculating an increase correction amount during acceleration according to the present embodiment.

FIG. 23 is a diagram (No. 1) for explaining the effect of the transient knock suppression control device of the present embodiment.

FIG. 24 is a diagram (No. 2) for explaining the effect of the transient knock suppression control device of the present embodiment.

FIG. 25 is a diagram (No. 3) for explaining the effect of the transient knock suppression control device in the present embodiment.

[Explanation of symbols]

M1 idle state detection means M2 intake air temperature detection means M3 cooling water temperature detection means M4 ignition timing calculation means M5 ignition timing control means M6 idle speed calculation means M7 idle speed control means M8 fan operating state detection means M9 acceleration injection quantity correction means M10 correction amount reducing means 10 internal combustion engine 12 intake passage 16 intake air temperature sensor 26 ISCV 32 water temperature sensor 34 spark plug 36 combustion chamber 60 electronic control unit (ECU) 62 vehicle speed sensor 64 neutral switch 66 AC switch 67 brake switch XIDL idle state flag XABSEIDL ignition timing retard determination flag THA intake air temperature THW coolant temperature XNSW neutral switch flag XSWB brake switch flag NT _ACON air conditioner operation at idle speed XATRNA idle speed setting determination flag C DL idle state continuation time counter

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02D 45/00 F02P 5/15 D F02P 5/15 E 5/153 F (58) Fields investigated (Int.Cl. ⁷ , DB) Name) F02P 5/145-5/155 F02D 41/00-45/00

Claims (3)

(57) [Claims] 1. An idle state detecting means for detecting that the internal combustion engine is in an idle state, an intake air temperature detecting means for detecting an intake air temperature of the internal combustion engine, a cooling water temperature detecting means for detecting a cooling water temperature of the internal combustion engine, When both the intake air temperature and the cooling water temperature are equal to or higher than a predetermined temperature, the ignition timing in the idle state is set to the intake air temperature.
And at least one of the cooling water temperatures is the predetermined temperature.
And an ignition timing control means for controlling the ignition timing of the internal combustion engine at a timing determined by the ignition timing calculation means as compared with the case where the ignition timing is less than the degree Knock suppression control device for internal combustion engine. 2. An idle state detection means for detecting that the internal combustion engine is in an idle state, an intake air temperature detection means for detecting an intake air temperature of the internal combustion engine, a cooling water temperature detection means for detecting a cooling water temperature of the internal combustion engine, When both the intake air temperature and the cooling water temperature are equal to or higher than a predetermined temperature, an idle speed calculation means for setting the engine speed in the idle state to a high rotation speed, and an engine speed for the rotation speed determined by the idle speed calculation means. A transient knock suppression control device for an internal combustion engine, comprising: idle speed control means for controlling the engine speed. 3. An intake air temperature detecting means for detecting an intake air temperature of the internal combustion engine, a cooling water temperature detecting means for detecting a cooling water temperature of the internal combustion engine, and an acceleration injection quantity for increasing and correcting a fuel injection quantity during acceleration of the internal combustion engine. A transient knock suppression control of an internal combustion engine, comprising: a correction unit; and a correction amount reduction unit that reduces an increase correction amount at the time of acceleration for a predetermined period when both the intake air temperature and the cooling water temperature are equal to or higher than a predetermined temperature. apparatus.