JPS60192826A - Control method of internal-combustion engine - Google Patents

Abstract

PURPOSE:To suppress knocking below allowable limit while bringing the increase of the output of an internal-combustion engine near to the maximum by performing supercharge while controlling the supercharging amount with correspondence to the cooling capacity of an intake air cooling means and the learning value of the firing timing. CONSTITUTION:A knocking sensor 10 will detect the knocking of engine to obtain the correction amount of the firing timing to the lagging angle side with correspondence to the degree of knocking while to set the learning value of the firing timing with correspondence to said correction amount. An inlet temperature sensor 22 and an outlet temperature sensor 24 will read out the cooling capacity of intake air cooling means or an intercooler 4 to function a step motor 32 on the basis of said learning value of the firing timing and the cooling capacity thus to open/close a waste gate valve 6. The amount of exhaust gas passing through a bypass 8 detouring a turbine 2a is controlled through opening/ closing of said valve 6 thus to control the supercharge pressure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling an internal combustion engine, and in particular, the present invention relates to a method for controlling an internal combustion engine, and in particular, by controlling the amount of retardation correction of ignition timing and the cooling capacity of an intake air cooling means provided on the intake side. This article focuses on a control method for an internal combustion engine that controls the amount of supercharging.

[Prior art] Research and popularization of internal combustion engines equipped with superchargers has been progressing in recent years in order to improve both the output and fuel efficiency of internal combustion engines. In addition to increasing the pressure within the combustion chamber due to internal combustion, the temperature of the intake air also rises as a result of adiabatic compression by the compressor, making internal combustion engines that use supercharging prone to knocking, a problem that was pointed out early on. In order to solve this problem, conventional methods include installing a cooler (intercooler) on the intake side to prevent the IB degree of intake air from increasing, and detecting the occurrence of knocking and adjusting the ignition timing accordingly.

Although a method of retarding the ignition timing has been proposed, excessively controlling the ignition timing to the retarded side not only raises the temperature of exhaust gas but also has another problem in that it also reduces fuel efficiency. In addition to having a negative impact on the three-way catalyst, the rise in exhaust gas temperature has a negative effect on the three-way catalyst. ) is undesirable as it may reduce the durability of the supercharger.

Figure 1 is an explanatory diagram showing an example of the relationship between the knocking frequency and ignition timing in a supercharged internal combustion engine. , Ar indicates the relationship between the knocking frequency and the ignition timing when regular fuel is used. θhgh is the amount of correction to the retard side of the ignition timing such that the frequency of knocking occurs below the allowable limit when using high-octane fuel, and θkgh is the amount of correction to the retard side when using regular fuel. On the other hand, there is a limit to correcting the ignition timing to the retarded side, where the ignition timing cannot be delayed any further due to the deterioration of exhaust gas temperature and fuel efficiency.
It is indicated by θ1iI11 in FIG. In this example, when using regular fuel, if you try to suppress the occurrence of knocking below the allowable limit, the ignition timing will exceed the limit, and if you try to keep the ignition timing within that limit, the frequency of knocking will increase. There is a paradoxical problem of not being within acceptable limits.

Therefore, we proposed that if the correction to retard the ignition timing of the internal combustion engine exceeds a predetermined value, the supercharging pressure would be reduced by a predetermined amount in order to reduce the amount of supercharging of intake air to the supercharger. has also been done. Arl indicated by a broken line in Fig. 1 indicates the relationship between the knocking frequency and the retardation correction amount when the boost pressure is reduced by, for example, 1100 m1H when regular fuel is used, and even when regular fuel is used. This shows that if the supercharging pressure is lowered, it is possible to achieve both the knock tolerance limit and the correction limit for retarding the ignition timing.

However, the supercharged internal combustion engine configured as described above still has the following problems.

In other words, (1) Boost pressure is adjusted by adjusting the ignition timing retardation amount, so when regular fuel is used, boost pressure must be adjusted frequently, which reduces the durability and reliability of the device. The first thing to do is to have enough sex.

(2) The supercharging pressure is adjusted too sensitively even when knocking occurs during a transient period, making it impossible to obtain sufficient output torque, which deteriorates the drivability felt by the driver during acceleration, for example.

(3) After knocking occurs and the ignition timing retard correction amount exceeds a predetermined value, the process of changing the boost pressure is repeated, so knocking is likely to be heard frequently and the durability of the internal combustion engine may be affected. Undesirable.

(4) The ability of the cooling means to cool the intake air is not always constant, and when the amount of intake air is at its maximum, such as during full-throttle acceleration, the intake air The occurrence of knocking may not be sufficiently reduced within the limits of the amount of correction to retard the ignition timing, for example, by simply uniformly lowering the boost pressure by a predetermined amount, such as when the temperature of the engine does not decrease significantly.

This is a problem.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to improve knocking control and ignition timing in an internal combustion engine that supercharges and cools intake air and performs ignition timing control. An object of the present invention is to provide an internal combustion engine control method that satisfies both control requirements.

[Configuration of the Invention] The configuration of the present invention made to achieve the above object is to supercharge the intake air of the internal combustion engine, cool the intake air with an intake air cooling means, detect knocking of the internal combustion engine, In a control method for an internal combustion engine, the ignition timing is controlled by a correction amount to the retard side of the ignition timing based on this and a learning value set according to the correction amount. The gist of the present invention is a method for controlling an internal combustion engine, characterized in that the amount of supercharging is controlled in accordance with the detected cooling capacity and the learned value of the ignition timing.

The basic configuration of the present invention is shown in the flowchart of FIG.

The series of processes shown in this flowchart are started while the internal combustion engine is being operated while being supercharged. First, in step P1, knocking of the internal combustion engine is detected, and in subsequent step P2, a correction amount to retard the ignition timing is calculated according to the degree of knocking of the internal combustion engine read in step P1, and the correction amount is adjusted to the retard side of the ignition timing. The learning value of the ignition timing is set accordingly. In step P3 following step P2, the cooling capacity of the intake air cooling means is read, and in the next step P4, the supercharging amount of the intake air is calculated from the learning value of the ignition timing obtained in step P2 and the cooling capacity of the intake air cooling means. Control processing is performed.

This completes the series of controls according to the present invention.

In the above configuration, there is no problem even if the processing of steps P1 and P2 and the processing of step P3 are reversed.

[Example] Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 3 is a schematic diagram of the internal combustion engine and its peripheral devices in the embodiment. In the figure, 1 is the main body of the internal combustion engine, 2
4 is a supercharger body that uses the flow velocity of exhaust gas to turn a turbine 2a provided in an exhaust flow path 3a and supercharges intake air by a compressor 2b provided in an intake flow path 3b; 4 is an intake air that cools the intake air; Intercooler as a cooling means,
Reference numeral 6 denotes a well-known wastegate valve 1 which is provided in a bypass passage 8 that bypasses the turbine 2a and adjusts the boost pressure.
0 each represents a knock sensor that detects knocking of the internal combustion engine 1. Further, 12 is an igniter which generates a high voltage in response to a control signal from the electronic control circuit 14;
6 is a distributor that distributes the high voltage to each cylinder of the internal combustion engine 1 in synchronization with the crank angle; 18 is a distributor for each cylinder 2;
Each figure represents a spark plug that is screwed onto the top of the 0 and generates an electric spark to ignite the air-fuel mixture. Further, 21 is a rotation speed sensor attached to the distributor 16 and detects the rotation speed of the internal combustion engine 1 from the rotation of the rotor 16a. Furthermore, 22 is the intake air 11 on the inlet side of the intercooler 4.
1 is an inlet temperature sensor that measures the intake air temperature, 24 is an outlet temperature sensor that measures the intake air temperature on the outlet side of the intercooler 4, and 26 is an air flow meter that detects the flow rate of intake air. It is configured to be able to detect cooling capacity. When the throttle valve 28 moves in the closing direction and the supercharging pressure of intake air becomes excessive, the waste gate valve 6 is opened by the actuator 30 to lower the supercharging pressure, but the electronic control circuit 14 When the step motor 32 rotates in response to a control signal from the waste gate valve, the waste gate valve is similarly controlled to open and close via the spring fill 34. Also, 36 is the throttle valve 2
This is a throttle sensor that detects the opening degree of 8.

Next, the internal configuration of the electronic control circuit 14 will be explained.
As shown in the figure, the electronic control circuit 14 includes a well-known 4-bit to 8-bit CPU 40. ROM41.

RAM42. Backup RAM44. input boat 46
．． Output boat 48. Consisting of a data bus 49, knocking and rotational speed of the internal combustion engine, cooling capacity of the intercooler 4, etc. are input according to the program described later, and the ignition timing and boost pressure of the internal combustion engine are controlled according to the data or calculation results based on the data. It is configured like this. The input port 46 includes a knock signal input circuit 46b that inputs a signal from the knock sensor 10, a pulse input circuit 46b that inputs a pulse signal from the rotation speed sensor 21, and an air 70 meter 26. Inlet temperature sensor 22. Outlet temperature sensor 24.
It has a built-in analog input circuit 46c that inputs analog signals from the throttle sensor 36, and converts each signal to the CP
It is output as a digital signal that can be handled by LJ and 40. or,
Electric power is supplied to the electronic control circuit 14 from a battery 54 via a key switch 52.

Next, the process of setting the learned value in the well-known ignition timing control for the control performed in the internal combustion engine and its control device having the above device/configuration will be explained using the flowchart in FIG. 4 from the learned value in the ignition timing control. The intercooler 4 is set according to the flowchart shown in FIG.
Another flag JDF detects the cooling capacity of the supercharging pressure IIJtll.

The flags KDF and IDF are set according to the flowchart shown in FIG. 6 for setting the IUF.

The process of controlling the boost pressure from the IUF is shown in FIG. 7 and will be explained using "Flowchart 1".

The ignition timing control for internal combustion engines, in which the ignition timing retardation correction amount is determined from the output of the knock sensor 10, is already well known, so the explanation will be omitted here. A processing routine (not shown) reads the output signal via the knock signal input circuit 46a of the input boat 46 and calculates the ignition timing retard correction amount θk depending on the degree (frequency and/or magnitude) of knocking in the internal combustion engine. The correction amount θ is R
It is stored in a predetermined area of AM42.

On the other hand, the learning value θ is set from the ignition timing retard side correction amount.
kQ・n is divided into four categories depending on the rotational speed of the internal combustion engine 1 and stored separately in a predetermined area of the RAM 42, and each is θka・2−・---・2000 to 3000 rpm θk
13...3000~4000rl) IIIθk
o −4−−−−−4000 to 5000 ppmθk
a・5−・−5000 to 6000 ppm.

Therefore, the learning value should be set for the internal combustion engine! 11 rotation speed is 200
This is carried out between 0 rpm and 6000 rpm, and in this range, knocking of the internal combustion engine 1 can be detected and ignition timing control can be performed, f) Internal combustion engines in which X ignition timing control is effective. It corresponds to the operating state of 1. In the following explanation, the learning value for ignition timing control will be represented by θkQ·n unless otherwise required.

When the rotational speed of the internal combustion engine 1 is within the above range, the control starts from A in FIG. 4, and first in step 100, 200 m5eo
A determination is made as to whether the time has elapsed.

The judgment in step 100 is rNOJ, i.e. 200II.
If ISeG has not elapsed, no processing is performed and control exits to B. If 200 III SCC has elapsed, the process proceeds to step 110, where the process is performed without reading out the ignition timing retard side correction amount θk stored in a predetermined area of the RAM 42, and in the subsequent step 120, the process proceeds to step 110.
It is determined in which range the value of the retard side correction fnOk read out at 0 falls, and a learning value is set in the following step. That is, the retard side correction amount θk calculated according to the degree of knocking is <a in the range of 2°CA to 46CΔ.
>θk<260A, the process moves to step 130, and the learned value θkQ·n is set to θkg·n=θkln−0,1.
0.16CA t as °OA: After subtracting and updating, go to B, (b) If 2°OA≦θ and ≦4°OA, learn value θkl
Exit to B without performing any process to update l/n, and if <C>θk>46CA, the process goes to step 140.
, and set the learned value θ1・n to θkill・n=θkg−n
After updating by adding 0.1'OA as +0.1°OA, the program exits to B and ends this control routine in which the ignition timing retard side correction amount θk sets its learned value θkg·n. Above step 1
Through the processes from step 00 to step 140, the learned value θkg・in addition to the ignition timing retard correction amount θ is stored in a predetermined area of the RAM 42 according to the rotational speed of the internal combustion engine 1.
This means that n is constantly updated and stored.

The actual ignition timing θ is based on the ignition timing when no correction is made to the retard side (here defined as the advance value from the ball dead center after compression, and referred to as θbase), and θ= θbase-θ is determined by -θkg-n-.-(1), and the ignition timing of the internal combustion engine 1 is actually controlled according to this. Therefore, for example, differences such as whether the fuel is high-octane fuel or regular fuel, equipment-specific machine differences, and changes over time are considered after the degree of knocking is detected and reflected in the ignition timing retard correction amount θk. , sequentially,
The learned value θkg-n is then transferred. As a result, even if the occurrence of knocking increases or decreases transiently, the ignition timing is corrected accordingly by the retard side correction amount θ, and the learned value θbg・n is not affected much by the transient phenomenon. It is decidedly determined.

Next, using the flowchart in FIG. 5, a description will be given of a routine for setting the supercharging pressure control flag KDF, which is performed in accordance with the learning value θk (1·n) of the ignition timing retard side correction amount described above. First, To give an overview of the control, this control routine is repeatedly performed using timer interrupts, etc., at timings unrelated to the ignition timing control described above.
The above learning value θhg·n (n is 2 to 5) stored in a predetermined area of the RAM 42 is used to set the flag KDF for controlling the boost pressure.
kg・2 is compared with the judgment level θref that determines whether or not to control the boost pressure in sequence, and four learning values (θk(]・2 to
If even one of θkg・5) exceeds θref, the flag KDF is set to 1, and even one of them exceeds θref.
If there is no value exceeding ref and there is at least one value below 2°OA, a process is performed in which the flag KDF is set to O. The judgment level is medium speed range (
2000rpm ~ 4ooorpm) and high speed range (40
00 rpm to 6000 rpm,) are set to different values.

In this control routine, which starts from FIG. 5C, first step 2
Initialization processing is performed at 00, that is, setting n=2,
In the following step 210, 1)≧4? In other words, it is determined whether the learned value in the medium speed range or the high speed range should be judged, and if the learned value is θkg・2 or θk
In the case of g・3, the process proceeds to step 220 and the judgment level θref is set to 6'CA. If the learned value is θk(]・4 or θkg・5, the process proceeds to step 230 and the judgment level θref is set to 6'CA. 4° OA, and then, in either case, the process moves to step 240. In step 240, a learning value is acquired from a predetermined area of the RAM 42 according to the currently set value of n (initially, n=2). θ
Read out kg-n (initially θkg·2). In the following step 250, the learned value θkg・1) becomes 2°GA~θre.
A determination is made as to what size relationship there is with respect to the range of f, and the process proceeds to a step corresponding to the determination. That is, (i) When θrg·n is 2°OA, the process is performed in step 26.
After the flag KDF for controlling the boost pressure is set to 0, the process proceeds to step 270.

(i+> 2°OA≦θrg-n≦θref (0 o'clock,
Processing simply continues to step 270.

(jii) When θ "9·n>θref, the process proceeds to step 280, sets the flag KDF to 1, and then exits this control routine to D and ends.

This process is performed. (+), (i+), the parameter n that determines the learning value is set to 1 in step 270.
(n = n + 1), and then continues (in step 290, it is determined whether n = 6, that is, the flag KDF that controls the boost pressure is set for the learned value θkg・2 to θkg・5). It is determined whether or not all setting processing has been completed. If not, the process returns to step 210; if it has been completed, the control routine is deemed to have been completed and exits to D.

Through the above processing, the learned value θkg·n (n=2 to 5
) According to the value of (1) at least one judgment level θre
If there is a learned value that exceeds f, the control based on ignition timing is considered to have exceeded the limit, and the process of setting the flag KDF to 1 in order to lower the boost pressure is performed (2) Even if none of them are at the judgment level There is no learned value exceeding θref, and 2
If there is only one learned value that is less than °OA, it is assumed that there is considerable margin for ignition timing control, and the process of setting the flag KDF to O to lower the boost pressure is (3) above ( If neither of the conditions 1) and <2) apply, processing is performed in which the flag KDF is not changed.

Next, the control for detecting the cooling capacity of the intercooler 4 and setting the flags IDF and IU'F for controlling the supercharging pressure will be explained based on the flowchart of FIG. 6. First, an overview of this control will be explained. In this control routine, the cooling capacity of the intercooler 4 is determined based on the temperature difference between the inlet side and the outlet side of the intercooler 4 when the internal combustion engine 1 is in a predetermined operating state. The flags IDF and IUF are set according to the capabilities.

This control routine enters from E and begins with step 30.0.
Then, the operating state of the internal combustion engine 1, here the rotational speed Ne of the internal combustion engine 1, and the throttle opening detected by the throttle sensor 36 are read.

In the next step 310, it is determined in step 300 whether the conditions for determining the cooling capacity of the intercooler 4 are satisfied.
The determination is made from the throttle opening degree and rotational speed Ne read in. The throttle valve is almost fully open and the rpm is 4000.
rpm or more, that is, the output of the internal combustion engine 1 is maximized, so knocking is likely to occur, and for this reason, the need to cool the intake air is the highest.In other words, the amount of cooling by the intercooler 4 is maximum. Determine whether the condition is met or not. If this is not the case, no processing is performed after step 31O, and control proceeds to F and ends.

On the other hand, if the judgment in step 310 is rYEsJ, that is, if the condition for determining the cooling capacity of the intercooler 4 is satisfied, the process proceeds to step 320 and step 330, and the inlet side temperature Tin of the intercooler 4 is measured by the inlet temperature sensor. 22, the outlet side temperature TOut of the intercooler 4 is read from the outlet temperature sensor 24, respectively. Step 320.
In step 340 following 330, a process is performed to calculate the temperature difference ΔT between the inlet side temperature Tin and the outlet side temperature fiT0ut, and in the next step 350, the intercooler 4 cooling capacity temperature detected last time (this is expressed as Ti-1) is calculated. 〉 and the temperature difference of 6 units, the intercooler 4 cooling capacity temperature (this is calculated as Ti
(2) is calculated using the following equation.

Ti = (Ti - tX 15 + ΔT)/16...
...(2) The reason why the temperature difference ΔK is not used directly here is to remove the influence of transient phenomena and noise, etc., and the cooling capacity temperature T1 is expressed as a first-order lag function value (smoothed value). Not defined.

In the following step 360, a process is performed to determine to which temperature range the cooling capacity temperature Ti determined in step 350 belongs, and flags IDE and ILIF for controlling the boost pressure are set.1! 1 (steps 370 and 380). That is, if (A) Ti <25°C,
It is assumed that the cooling capacity of the intercooler 4 is quite low, and the process moves to step 370, where the flag IOF for controlling the boost pressure to decrease is set to 1, and the flag I for controlling the boost pressure to increase.
When UF is O, and (B) 25°C≦Ti≦45°C, the cooling capacity of intercooler 4 is considered normal, and the flags IDE and I are
If both UF and (C)Ti are set to O and (C)Ti > 45°C, it is assumed that the cooling capacity of the intercooler 4 is quite high, and the process moves to step 380 to set the flag IDF.
is set to O and IUF is set to 1, and after any one of (A>, (B), and (C)) is performed, the process exits to F and ends this control routine.

As a result of executing this control routine, flags IDF and IU, which control boost pressure according to the cooling capacity of intercooler 4,
This means that F has been set.

Next, the flag KDF (set by the Gakushin value, which is one of the correction amounts to the retard side of the ignition timing) that controls the boost pressure explained using the flowchart in FIG. 5, and the flag 70 in FIG. -Another flag IDF for controlling the boost pressure explained using the chart 1r.

The process of controlling the boost pressure according to the IUF (set by the cooling capacity of the intercooler 4) will be explained with reference to the flowchart in FIG.

Prior to this control routine, a 1-bit flag F1. is used in this control routine when starting the internal combustion engine 1. F
2. Setting of F3 is performed. At first, Fl and F2 are both set to O, and F3 is set to 1, with no supercharging pressure being controlled at all.

This control routine is started at appropriate intervals by a timer interrupt or the like and enters from S. First, in step 400, it is determined whether the flag KDF is 1 or not. KDF is 1
In this case, since the correction to the retard side of the ignition timing has reached its limit and it is necessary to reduce the boost pressure, the process proceeds to step 410, and in step 410 it is determined whether the flag F1 is O or not. Do the following. Flag F1 is flag, D
This flag indicates whether or not the boost pressure reduction process based on the value of F has already been performed, so if F1=0, it is determined that the boost pressure has not been reduced due to the request from the ignition timing side. The process proceeds to step 420, in which a pulse signal is output to the step motor 32 via the output port 48, and a process is performed to reduce the boost pressure by approximately 1001111111-1(]. receives a pulse signal through the step motor 3
2 rotates toward the r1 side in FIG. 3, the spring coil 3
4, the wastegate valve 6 is opened, and the proportion of exhaust gas that is discharged through the bypass 8 without being involved in the turbine 2a increases, so the capacity of the compressor 2b that is linked to the turbine 2a decreases. As a result, the boost pressure is lowered and the amount of boost is also reduced.

On the other hand, if the determination at step 400 is "NO", that is, the flag KDF is not 1 but 0, and from the ignition timing side,
If there is still room for control, the process proceeds to step 430.
The process advances to step 410 and flag F1 is determined. If F1=1 and the supply pressure reduction process has already been performed, the process proceeds to step 440 and moves the step motor 32 in the direction r2 in FIG. 2, contrary to the process in step 420. and control the waste gate valve 6 in the direction of closing to increase the supercharging pressure to 1100IIIllH.
Processing to increase the number is performed. After the process of step 440 or after the process of step 420 described above, the process proceeds to step 450, where the 1-bit flag F1 is inverted. In other words, the process of step 440 (
If the process of step 420 (reduction of supercharging pressure) is performed, the flag is set to Fl-1 because F1=0. F1 is inverted.

After the processing in step 450 above, or in step 41
0 or if the judgment in step 430 is rNOJ and there is no need to control the boost pressure using the flag KDF, the process proceeds to step 500, and in step 500 to step 550 J3 determines the cooling capacity of the intercooler 4 ( The process of controlling the boost pressure is performed according to the value of the flag IDF, which is set to reduce the boost pressure according to Ti>.Steps 500 to 55
Each process of step 0 is performed in step 400 to step 4 described above.
This is done based on the same concept as each process in steps 400 to 450, and instead of the flag KDF used in the processes in steps 400 to 450, the flag IDE, which is set according to the cooling capacity of the intercooler, is used instead of the flag F1. F2 is used, and the boost pressure is controlled in steps 550 and 520 so that it is reduced and restored by 5Qn+m1-(Q. Therefore, steps 500 to 55
0 processing is omitted, but by the processing from step 500 to step 550, internal combustion is Control is performed such that the supercharging pressure of the engine 1 is reduced by 50 mmH ( ), and when the cooling capacity is restored to above normal, the supercharging pressure is also increased by 50 nunHQ and restored to its original state.

The processing in steps 600 to 650 following the processing in step 550 is also configured based on the same concept as the processing in steps 500 to 550, so the explanation will be omitted, but the supercharging in steps 600 to 650 will be omitted. The pressure is controlled using the flag IU instead of the flag IDF used in steps 500 to 550.
Flag F3 is used instead of flag F2, and in step 600 corresponding to step 500, instead of determining whether IDF=1, it is determined whether IUF=O. . This is the flag ID
In the case of F, the boost pressure was defined to be reduced when the value was 1 (increase to the original value when it was O), whereas in the case of the flag ILJF, when the value was 1, the boost pressure was defined to be reduced. This is because it is defined to increase the boost pressure (when it is 0, it decreases to the original value). Step 600 to Step 650
As a result of the processing, when the cooling capacity of the intercooler 4 is high using the flag ILJF (when Ti>45°), the boost pressure of the internal combustion engine 1 increases by 5oIIIllHg,
If the cooling capacity is no longer high, increase the boost pressure to 50R.
Control is performed to reduce the pressure by 11IIHg and restore it to its original state, and then the control exits to R and ends this control routine.

In this embodiment configured as described above, (a) a learned value (θk
When the ignition timing is retarded to the limit depending on the value of g-n), the boost pressure is reduced by 100111 days ill,
When there is sufficient margin in the ignition timing, the boost pressure is restored to normal. (b) Depending on the cooling capacity of intercooler 4, when the cooling capacity is low, the boost pressure is reduced by 50 mmHg to ensure that the cooling capacity is sufficient. When high, boost pressure is 50mmH.

increased processing and It is configured to do the following.

Therefore, in a supercharged internal combustion engine equipped with an intercooler 4, the ignition timing is controlled by learning from the ignition timing control that is performed by detecting knocking depending on the difference in fuel octane number, etc., and the ignition timing is When it is necessary to correct the angle to be retarded than the limit range, the boost pressure is reduced to suppress the occurrence of knocking, and in addition to controlling the ignition timing within the permissible combustion range, the cooling capacity of the intercooler 4 is increased. The system detects this and increases or decreases boost pressure, making it possible to control the internal combustion engine more precisely. In other words, even if the boost pressure is reduced by 100 mmt-1g due to the request from the ignition timing control side, if the intercooler 4 has sufficient cooling capacity and the intake air is cold, the boost pressure will be increased by 5011ml-19 to reduce the internal combustion. Control is performed such that the output of the engine 1 can be increased, while if the cooling capacity of the intercooler 4 is insufficient, the boost pressure is further reduced by 5 Q mml-1 g to prevent the occurrence of knocking. I can do it. In addition, the learned value is used as the correction amount to the retard side of the ignition rRwJ, the near-first-order function value is used as the cooling capacity of the intercooler 4, and the value between the inlet and outlet sides of the intercooler 4 is used when determining the cooling capacity. An intermediate range of 25° to 456 degrees is provided for the temperature difference of tDF to increase or decrease the boost pressure.

Since IUF2Ii- is set, the supercharging pressure is controlled relatively slowly and drivability is not impaired. Furthermore, the device for controlling the boost pressure needs to have low responsiveness, and both reliability and economic efficiency can be improved. Furthermore, in this embodiment, the step motor 32 is used to drive the waste gate valve 6, and the tension of the spring coil 34 is changed to open and close the waste gate valve 6. Therefore, even when the supercharging pressure changes, the step motor 32 is used to drive the waste gate valve 6. Changes occur slowly, solving the problem of poor drivability due to sudden changes in boost pressure.

In this example, the boost pressure increases and decreases by 100 mmH9,
50 + n + nH (J), but there is no need to limit it to this value, and the optimum value can be selected according to the characteristics of the internal combustion engine to which it is applied. Also, the boost pressure can be increased or decreased in multiple stages depending on the learned value of the ignition timing. Alternatively, it is also possible to control the internal combustion engine more precisely by increasing and decreasing the boost pressure in multiple stages depending on the cooling capacity of the intercooler.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and it goes without saying that it can be carried out in the shape of M without departing from the gist of the present invention. .

[Effects of the Invention J As detailed above, the method for controlling an internal combustion engine of the present invention supercharges the internal combustion engine, cools intake air by the intake air cooling means, and controls the ignition timing based on the output of the knocking detection means. In a 1lilJ control method for an internal combustion engine in which the ignition timing is controlled by a correction amount to the retard side and a learned value set according to the correction amount, the cooling capacity of the intake air cooling means is detected, and the cooling capacity and the ignition timing are The supercharging pressure is controlled according to the learned value of.

Therefore, the amount of supercharging of the internal combustion engine depends on the two factors involved in the occurrence of knocking: the learned value set as the amount of correction to retard the ignition timing, and the degree of cooling of the intake air to be supercharged. It is possible to control the internal combustion engine by increasing and decreasing the amount of the internal combustion engine minutely. In other words, by controlling the amount of supercharging by combining these two factors, it is possible to maximize the increase in output of the internal combustion engine that can be achieved by supercharging, while suppressing the occurrence of knocking below the allowable limit. Moreover, an effect has been obtained in that the ignition timing can be controlled so as not to exceed the limit of correction to the retard side that is permissible for combustion.

In addition, since the learned value of the ignition timing is used, boost pressure control will not be repeated frequently when the internal combustion engine is in a transient state, and drivability will not be impaired. It also has secondary effects.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram explaining the relationship between ignition timing and the occurrence of knocking, Fig. 2 is a basic configuration diagram of the present invention, and Fig. 3 is an internal combustion engine and its peripheral equipment of an embodiment to which the present invention is applied. Fig. 4 is a flowchart showing the process of setting the learned value (θk) from the correction amount (θk) to the retard side of the ignition timing according to the level of knocking, Fig. 5 6 is a flowchart showing the process of setting the flag KDF for controlling the boost pressure from the learned value, and FIG. 6 shows the flag IDE for controlling the boost pressure by detecting the cooling capacity of the intercooler.
, I(JF), FIG. 7 is a flowchart showing the control of supercharging pressure performed using ILIF. 1... Internal combustion engine 2... Supercharger 4...Intercooler 6...Wastegate pulp 10...Knock sensor 14...Electronic control circuit 22...Inlet temperature sensor 24...Outlet temperature sensor 34...Step motor 40...・・CPU agent Patent attorney Tsutomu Seitatsu and 1 other person）Mainly 4% $ Figure 1 0 - and the retardation amount/'CAノ

Claims (1)

[Claims] In addition to supercharging the intake air of the internal combustion engine, the intake air is cooled by the intake air cooling means, and on the other hand, the occurrence of knocking in the internal combustion engine is detected, and this! ,:Based≦In a control method for an internal combustion engine, the ignition timing is controlled by a correction amount to the retard side of the ignition timing and a learning value set according to the correction amount,
A method for controlling an internal combustion engine, characterized in that the cooling capacity of the intake air cooling means is detected, and the amount of supercharging is controlled according to the detected cooling capacity and the learned value of the ignition timing.