JPS63138136A - Control device for fuel injection amount - Google Patents

Abstract

PURPOSE:To enhance an effect of preventing a temperature rise, by performing the correction immediately when an ignition delay timing value increases to a predetermined value or more, in the case of an engine in which a fuel injection amount is corrected after the predetermined delay time in accordance with a fuel increase correction amount for preventing a temperature rise of exhaust gas. CONSTITUTION:A correction amount arithmetic means M2, which calculates an increase correction amount of fuel injection for preventing a temperature rise of exhaust gas in accordance with an operative condition, for instance, speed, load, ignition timing, etc. of an internal combustion engine EG, is provided. And the engine, in accordance with this increase correction amount, corrects by a delay correction executing means M3 the actual fuel injection amount after the predetermined delay time suppressing the temperature rise of the exhaust gas and preventing a catalyst or the like in an exhaust gas purifying device from deteriorating. In a control device as described in the above, the delay correction executing means M3 is equipped with an instantaneous execution part M4 which performs the above described correction immediately when an ignition delay timing value, calculated in accordance with an engine operative condition in an ignition delay timing value arithmetic means M1, increases to the predetermined value or more.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for controlling the fuel injection amount of an internal combustion engine such as an automobile. Fuel injection control (
1 device.

[Prior Art] It is known that the temperature of exhaust gas from an internal combustion engine changes depending on its rotational speed, load, and amount of ignition timing retardation, and becomes high at high rotation and high load. On the other hand, assuming that the rotational speed, load, and ignition timing retardation of the internal combustion engine are constant, the exhaust gas temperature reaches its maximum when the air-fuel ratio of the combustion mixture is slightly larger than the stoichiometric air-fuel ratio; It is known that as the fuel becomes smaller, that is, as the fuel becomes richer, it decreases.

If the exhaust gas temperature rises excessively, the catalyst in the exhaust gas purification system will deteriorate prematurely, so conventionally, when an internal combustion engine is operated at high speeds and under high load, the air-fuel ratio of the air-fuel mixture becomes slightly low (fuel-rich). The fuel injection m was corrected as follows. However, such an increase in the amount of fuel injection tJ1 naturally worsens fuel efficiency, and also increases the temperature of the exhaust gas after the internal combustion engine enters a high rotation and high load state until the temperature of the exhaust gas actually rises to a certain extent. Since it takes some time, the above-mentioned increase correction is executed after some delay time has elapsed.

Various proposals have been made as methods for determining this delay time. For example, Japanese Patent Application Laid-Open No. 58-5124 'I @ Publication suggests that it is determined according to the rotational speed and load of the internal combustion engine, and Japanese Patent Application Laid-Open No. 60-1989 Publication No. 53645 shows that the delay time can be changed depending on the rate of change in load increase.
JP-A-53431 discloses changing the temperature in accordance with the temperature of the cooling water of the internal combustion engine.

[Problems to be Solved by the Invention] In recent years, the number of internal combustion engines equipped with a so-called turbocharger or supercharger, which supercharges a combustion chamber with an air-fuel mixture, has been increasing in order to increase the output of the internal combustion engine. Since knocking is generally likely to occur in such supercharged internal combustion engines, a knock control device is often provided. The temperature of exhaust gas from an internal combustion engine increases more easily by adding a supercharger, but if a knock control device is added, the temperature of exhaust gas may rise even more and faster. The reason is as follows.

Figure 2A shows the relationship between the ignition timing (as it moves to the right on the horizontal axis, it advances to BTDC before top dead center) and the generated torque when the rotational speed of the internal combustion engine is constant. It shows air 5107N as a parameter. Under normal operating conditions, the ignition timing is set approximately as shown by solid line A relative to Q/N, but when low octane gasoline is used in an internal combustion engine equipped with a knock control device, etc. The ignition timing is controlled by the knock control device.
;Set to the value shown by A8. In other words, the ignition timing may be delayed compared to normal.

Figure 2B shows how the amount of fuel injection amount increase 1 necessary to prevent a rise in exhaust gas temperature changes when the ignition timing is changed, also using Q/N as a parameter. It is something. The ignition timing is changed for various purposes other than the knock control device described above, such as when the cooling water temperature of the internal combustion engine rises excessively. However, it has been shown that when the ignition timing is delayed, the required increase correction amount increases regardless of the value of Q/N. Furthermore, as the amount of retardation of the ignition timing increases (toward the left on the horizontal axis in Fig. 2B), the slope of the curve becomes steeper, and the change in the required increase correction amount in response to a change in the ignition timing becomes larger, i.e. It can also be seen that the temperature of the exhaust gas rises rapidly.

As mentioned above, when the amount of ignition retard increases due to internal combustion engine knock control, etc., the amount of increase correction to prevent the exhaust gas temperature from rising increases more than before, and the time during which the temperature rises also becomes shorter. A situation arises and it costs 1q. In such a case, if the conventional fuel injection amount control as described above is performed, deterioration of the catalyst and exhaust pipe of the exhaust gas purification device cannot be prevented.

The present invention has been made to solve these problems, and provides a fuel injection system that can sufficiently prevent the temperature rise of exhaust gas even in an internal combustion engine equipped with a supercharging device, a knock control device, etc. A quantity control I device is provided.

[Means for solving problems].

The present invention, which has been made in view of the above-mentioned problems of the prior art, provides an ignition timing 111 which uses the ignition timing retard amount according to the operating state of the internal combustion V1 engine EG, as shown in FIG.
1 retard ω calculating means M1; a correction value calculating means M2 for calculating a fuel increase correction value for preventing a rise in exhaust gas temperature according to at least the ignition timing retard amount; and after a predetermined delay time, the fuel increase correction value In the fuel injection ω control device FC including a delay correction execution means M3 that corrects the actual fuel injection amount by is an immediate execution unit M4 that immediately performs the above correction.
The gist of the present invention is a fuel injection amount control device FC characterized by having the following features.

[Function] The ignition timing retard M sieve means M1 retards the ignition timing in order to reduce the frequency of knocking, etc., depending on the operating state of the internal combustion engine rAEG, such as the knocking occurrence state and the cooling water temperature. Disguise the amount of angle.

The correction value calculation means M2 calculates an increase correction value for the fuel injection amount to prevent the temperature of the exhaust gas from rising in accordance with at least the retardation amount calculated by the ignition timing retardation amount calculation means M1. In addition to the ignition timing retard amount, this increase correction value may be changed depending on parameters such as the rotational speed and load of the internal combustion engine, if necessary.

The delay correction execution means M3 receives the fuel increase ω correction value calculated from the correction value calculation means M1, but it corrects the actual fuel injection amount and increases the fuel injection amount based on the rotational speed of the internal combustion engine, It starts after a predetermined delay time has elapsed from the time when it is determined that the above-mentioned increase correction is necessary based on operating conditions such as load and ignition timing retardation. This is because it takes some time from when such a determination is made until the temperature of the exhaust gas actually rises. An immediate execution unit M4 included in the delay correction execution unit M3 receives the ignition timing retard amount,
As soon as the value exceeds the predetermined value, even within the delay time, the fuel injection amount is immediately increased using the calculated increase correction value.

[Example] An example in which the present invention is applied to fuel injection amount control of an electronically controlled four-cylinder gasoline engine with a supercharger will be described below. FIG. 3 shows a schematic configuration of an engine, an electronic control device, and related devices to which this embodiment is applied. An air flow meter 3 is provided in the intake passage 2 of the engine body 1. The air 70 meter 3 directly measures the amount of intake air, and has a built-in potentiometer to generate an analog voltage output signal proportional to the amount of intake air. This output signal is sent to the multiplexer built-in A/D converter 310 of the control circuit 10.
1 is supplied. The distributor 4 has a crank angle sensor 5 whose shaft generates a pulse signal for detecting a reference position every 720 degrees in terms of crank angle, and a pulse signal for detecting a reference position every 30 degrees in terms of crank angle. A crank angle sensor 6 is provided that generates. The pulse signals of these crank angle sensors 5 and 6 are supplied to the input/output interface 106 of the control circuit 10, and the output of the crank angle sensor 6 is supplied to the interrupt terminal of the CPtJ 107.

The primary current flows to the primary coil of the ignition coil 7 and the igniter 8
When supplied from the ignition coil 7, the high voltage secondary current of the ignition coil 7 is supplied to the ignition plug 9 provided for each cylinder via the distributor 4. Strictly speaking, when the igniter 8 starts energizing, current flows through the primary coil of the ignition coil 7.
At the same time as the igniter 8 is de-energized after a predetermined time,
A high voltage secondary current is generated in the secondary side coil of the ignition coil 7, and ignition is executed. In addition, igniter 8
The energization control is performed by the control circuit 10.

Roughly speaking, the intake passage 2 is provided with a fuel injection valve 11 for supplying pressurized fuel from a fuel supply system to an intake port for each cylinder.

Further, a water temperature sensor 13 for detecting the temperature of cooling water is provided in the water jacket 12 of the cylinder block of the engine body 1. The water temperature sensor 13 generates an analog voltage electrical signal according to the temperature THW of the cooling water. This output is also supplied to the A/D converter 101.

Generally speaking, the cylinder block 12 is provided with a vibration type knock sensor 14 that detects a knocking state of the engine.

The knock sensor 14 is provided in only one cylinder and is arranged so as to detect knocking conditions in other cylinders as well.

The output of the knock sensor 14 is supplied to a bandpass filter (BPF) 103 of the control circuit 10. This bandpass filter 10
3 is for passing only the knock control frequency range, and its output is the peak hold circuit (P/H) 1.
04 and an integrating circuit 105. The peak hold circuit 104 is for storing the maximum value a of the output of the bandpass filter 103 for a predetermined period, and the integrating circuit 105 is for generating the average value a of the output of the bandpass filter 103. Here, if the maximum value a is a knock component and the average value is a background value, it is considered that a knock has occurred when a>)(-b (K is a constant) is satisfied.

In other words, the background value is used as a knock judgment criterion.
This is a parameter that determines b, and usually changes depending on the engine rotational speed Ne. Peak hold circuit 10 described above
4 and the outputs of the integrating circuit 105 are supplied to an A/D converter 102 with a built-in multiplexer.

Air flow meter 3 and throttle valve 15 in intake passage 2
In between, there are provided a turbocharger 16 that uses exhaust energy to supercharge intake air, and an intercooler 17 that cools the air that has been compressed by the turbocharger 6 and whose temperature has increased. Exhaust is turbocharger 16
After passing through, it passes through a three-way catalyst device 18 and is discharged.

The control circuit 10 is mainly composed of a microcomputer CPU107, and includes a ROM108. R
AM109. A down counter (C) 110, a flip-flop (FF>111., a drive circuit (D) 112, etc.) are provided.
Flip 70 Tsubu 111. and a drive circuit 112 for controlling the fuel injection valve 11. That is, in the routine described later, when the fuel injection ff1TAU (actually time) is calculated, the fuel injection ff1TAU is preset in the down counter 110 and the flip-flop 111 is also set. As a result, drive circuit 1
12 starts energizing the fuel injection valve 11. On the other hand, when the down counter 110 counts the clock signal (not shown) and the carrier terminal finally reaches 1 level, the flip-flop 111 is reset and the drive circuit 112 controls the fuel injection valve 11. The energization is stopped.In other words, the fuel injection valve 11 is energized by the amount of fuel injection ITALI described above, and therefore, fuel is sent into the combustion chamber of the engine 1 the number of times corresponding to the fuel injection m T A tJ.

Note that the interrupt generation of CPtJ107 is caused by A/D converter 1.
01.102 when the A/D conversion ends, when the input/output interface 106 receives the pulse signal from the crank angle sensor 6, etc.

The intake air amount data Q and the cooling water temperature data THW of the air flow meter 3 are taken in by an A/D conversion routine executed at predetermined time intervals and stored in a predetermined area of the RAM 109. In other words, data Q and data 1-IW in the RAM 109 are updated at predetermined intervals. Further, the rotational speed data Ne is calculated by the interruption of the crank angle sensor 6 every 30'' CA, and is stored in a predetermined area of the RAM 109.

4A and 4B illustrate the operation of the control circuit shown in FIG. 3.

This will be explained with reference to the flowcharts in FIGS. 5 and 7.

FIG. 4A and FIG. 4B are a knocking determination routine and a knocking frequency calculation routine, respectively, and both are performed at each predetermined crank angle, for example, 60° BTDC (before top dead center) and TDC (top dead center) of each cylinder. In accordance with this, if there are four cylinders, each cylinder is executed every 180'CA (crank angle). In other words, it is executed in accordance with the range in which knocking can occur.

In the routine of FIG. 4A, the operation of the peak hold circuit 104 is started in step 301, and the routine ends in step 302. The routine of FIG. 4B is then executed at a predetermined crank angle, for example 60'C11.

In the routine of FIG. 4B, in step 401, a counter NreV for measuring the engine rotation speed, for example, 2 rotations (720° CA>) is incremented by 1. That is, each time the counter NreV reaches Nrev=4, Cycle-2 revolutions (720' CA) can be detected.Next, in step 402, the peak hold value a is A/D converted and taken in by the peak hold circuit 104, and in step 403, the repeat peak hold value a is taken in by the peak hold circuit 104. The background value is converted to A/D and imported.

Next, in step 404, it is determined whether or not a>K"b (K is a constant value). If a>K-b, the knocking detection counter N is incremented by 1 in step 405, and a
If ≦−b, the process directly advances to step 406.

In step 406, it is determined whether NreV>4, that is, 2
Determine whether or not it has rotated (720″CA).2 rotations (
720''CA), the knocking@degree counter N is set to N in step 407. In other words, the knocking frequency counter N indicates the number of knocking occurrences per two revolutions of the engine. The counter NreV is cleared in step 409, and the counter N is cleared in step 409. Then, in step 410, the operation of the peak hold circuit 104 is canceled, and in step 411, this routine ends.

FIG. 5 shows an ignition timing calculation routine, which is executed every 180'' CA at a predetermined crank angle, for example, for 4 cylinders. In step 501, intake air amount data Q and rotational speed data Ne are read from the RAM 109; Based on the data, the basic ignition timing θB is calculated by interpolation using a two-dimensional map stored in the ROM 10B.Next, in step 502, it is determined whether the engine satisfies knocking feedback control conditions (KC3 conditions). The knocking feedback control condition is, for example, cooling water@THW≧60°C.In other words, when the engine is cold (THW<60°C), the clearances of various parts of the engine are large, so engine vibrations other than knocking ( As a result, the knocking detection performance is poor, or the knocking feedback control malfunctions. Therefore, when the engine is cold, the process proceeds to step 507 without performing the knocking feedback control, and the knocking AKC between correction retard angles
8@O.

If the knocking feedback control conditions are satisfied, the process proceeds to steps 503 to 506, where knocking feedback control is performed. That is, in step 503, it is determined whether the knocking frequency counter N is equal to 0 or not. In a supercharged engine like the one in this embodiment, knocking is likely to occur, especially when gasoline with a low octane number is used, and the occurrence of knocking has a negative effect on the durability of the engine. If knocking occurs (N≠
O) The process proceeds to step 504, where retard control is performed in accordance with the knocking frequency N. That is, AKC3+-AK
C3+Δθ1 (to N) However, the retard interval Δθ1 (to N) changes depending on the knocking frequency NK. On the other hand, if knocking does not occur (N = O)
, the process advances to step 505 and advance angle control is performed. That is,
AKC34-AKC3-Δθ2 Note that Δθ2 can be a constant value or can be a value depending on the elapsed time. And step 50
In step 6, the knocking correction retard angle mAKC8 is guarded in the range 0<AKC3≦AKC3MAX, where the maximum value AKC3MAX changes depending on Q/Ne and Ne. That is, AKC3
A value of AKC3 larger than MAX is fixed to AKC8MAX. This ends the knocking feedback control. Note that AKC3 is stored in the RAM 109.

In step 508, the cooling water temperature data THW@ is read out from the RAM 109 and a one-dimensional map stored in the ROM 108 is used to perform high temperature retard control. In other words, high temperature correction retard angle f
Worship f1AHOT. This is engine cooling water mT
This is to forcibly reduce the engine output to lower the engine cooling water temperature when the HW reaches a very large value, for example 100° C. or higher, and to avoid excessive knocking. AHOT has RAM109
is stored in

In step 509, the above two types of correction retard angles ωAKC8 and A
HOT is added to obtain the total corrected retard angle ffiAsLJM, and in step 510, the ignition timing θ is set as θ←θB −ASt
Performed by JM. In step 511, as shown in FIG. 6, the ignition vg period θ (crank angle) is converted into time using the current time and rotational speed Ne, and the energization end time te is calculated, roughly before 30'CΔ. The energization start time ts is calculated. The energization start time ts and energization end time te calculated in this way are set in a counter for ignition timing control (not shown), or in a conveyor register for ignition timing control if the free run counter control method is used. Become. As a result, the igniter 8 shown in FIG. 3 starts being energized at the energization start time ts, and ends energization at the energization end time te to perform ignition.

The routine of FIG. 5 ends at step 512.

In addition, in the routine shown in Fig. 48, the knocking frequency N is calculated by detecting knocking whose knocking intensity exceeds a certain level. Detects small knocks and medium knocks.

It is also possible to calculate the knocking frequency for each large knock. In this case, the retardation amount Δθ1 in step 504 in FIG. 5 is also a small knock or a medium knock.

Can be changed for each big knock. For example, when a medium knock or a large knock is detected, the retard amount is set to be twice or three times that of a small knock, respectively.

FIG. 7 shows an injection amount stop routine, which is executed at every predetermined crank angle, for example, every 360'' CA.

In step 701, the RAM 109 reads the intake air data Q and the rotational speed data Ne@, and performs basic injection 1.
Calculate tTP. For example, tTP← is 1・Q/Ne(
K1 is a constant).

In steps 702 to 704, a first fuel increase correction amount tFOPTI is calculated to prevent an increase in exhaust temperature due to an increase in rotational speed and load. Zunawara, step 70
2, the rotational speed data Ne is read from the RAM 109 and the FOTP is determined using the one-dimensional map stored in the ROM 108.
NE is calculated by interpolation, and in step 703, the above data Ne
At the same time, intake air amount data Q'I from RAM109! ! :
Read and calculate Q/Ne, and roughly based on Q/Ne, use the one-dimensional map stored in the ROM 108 to calculate FOT.
PQN is calculated by interpolation 31, and both are added in step 704 to obtain tFOTP1←FOTPNE+FOTPQN.

In steps 705 and 706, a second fuel increase correction 1tFOPT2 is calculated in order to prevent an increase in exhaust temperature due to ignition timing retard control. That is, step 705
1 stored in the ROM 108 based on Q/Ne.
Interpolate KQN by dimensional map if W, step 7
In 06, the total retardation mother data AS is further stored in the RAM 109.
Read UM and make second fuel increase W correctionff1tFOPT
2 is calculated by tFOPT2←KQN-ASLIM2. In other words, the second fuel increase correction amount tFO
PT2 is calculated using a quadratic function of the amount of retardation.

In step 707, tFOTP-tFOPT1+tFOPT2 is added to obtain the final fuel increase correction amount tFOTP.

In step 708, it is determined whether the calculated increase correction amount tFOTP is a positive value. In the map used in step 703, FOTPQN is set so that it can take a negative value, so tFOTP can also take a negative value, but the fact that the calculated value tFOTP of the increase correction ω is negative means that the increase correction In order to show that there is no need, in this case, the timer CFOTP is reset to O in step 709, and the execution value FOT of the increase correction amount is set in step 710.
As P@O, fuel injection ωTA in step 716 described below
Calculate LI. That is, the main weight increase correction is not performed.

If it is determined in step 708 that tFOTP>O, then in step 711 it is determined whether the actual value FOTP of the increase correction amount is O. The flight increase correction amount execution value FOTP is determined in step 710 described above or step 715 described below, but unlike the fuel increase correction amount calculation value tFOTP, it is a value that is incorporated into the calculation of the actual fuel injection ff1TAU. Therefore, the determination in step 711 is to determine whether or not an increase correction is currently being performed. If FOTP≠0, that is, if the increase correction is currently being performed, the process proceeds to step 715 and the total drop value tFOTP is set as the execution value FOTP. If it is FOTP-0, the process proceeds to step 712, and the ROM 108 is stored based on tFoTP-0.
The delay time C0TDLY is determined by the one-dimensional map stored in
Calculate by interpolation. Then, in step 713, the timer CF
It is determined whether the OTP exceeds the delay time C0TDLY. The timer CFOTP starts counting from when the edge increase correction amount meter 1 becomes a positive value (step 7).
08.709). If the current time is within the delay time C0TDLY, the process advances to step 714, and it is determined whether the value of the total corrected retard angle ffiAsUM calculated in the ignition timing retard routine (Fig. 5) and stored in the RAM 109 is equal to or greater than a predetermined value C. Determine whether or not.

If ASUM≧C, the process proceeds to step 710, and the increased m correction execution value FOTP80 is set. On the other hand, if ASUM is C, the process proceeds to step 715, and the increase correction aI calculated value tFOT is reached.
Actual fuel injection fJJ! in step 716 with P as the execution value FOTP! 1TAtJ, TALJ(-tTP・(1
+FOTP)・α+β. Note that α and β are correction amounts determined by other operating state parameters,
For example, a signal from a throttle position sensor (not shown),
Alternatively, it is a correction amount determined by a signal from an intake temperature sensor, battery voltage, etc., and these are also stored in the RAM 109.

In step 713, the current time is the delay time C0TDL.
If it is determined that Y has been exceeded, the process proceeds to step 715 and processes the above book, that is, a predetermined delay time C0TD.
LYI! 2 executes the price increase correction.

This completes this routine, and the fuel injection ff1TAU calculated in this routine is used for injection control of the fuel injection valve 11 in another injection execution routine.

That is, the TAU is set on the down counter 110 and the flip 70 knob 111 is set to start fuel injection. When the time corresponding to the injection (ITAU) has elapsed, the flip-flop 111 is reset and the fuel injection ends.

In the above embodiment, the control circuit 1o and the routine shown in FIG. Steps 711 to 716 of the routine shown in FIG.
0 corresponds to the immediate execution unit M4.

In the above embodiment, the ignition timing retard angle fflAsUM is set to a predetermined value in step 714 of FIG.
It is determined whether or not it is equal to or greater than i1c, and if it is equal to or greater than a predetermined value C, the process immediately proceeds to step 715.7 without performing delay processing for correcting the increase in flights.
16, the increase correction is executed. In other words, when the amount of ignition timing retardation becomes large (V (see Figure 2B), which has a large effect on the temperature rise of exhaust gas, it is predicted that the temperature of exhaust gas will rise rapidly, so the fuel increase correction should be carried out immediately. This is done to prevent deterioration of the exhaust pipe, three-way catalyst device 18, etc. Furthermore, the degree of knocking chain, which causes an increase in the ignition timing retard m, can also be reduced. An example of this is shown in the timing charts of FIGS. 8A and 8B. Fig. 8A shows the changes in the knock level, ignition timing retard period, fuel increase correction value, and exhaust gas temperature when using the conventional technique.
Even if the calculated itching value of the mouth correction value increases rapidly due to an increase in fiAsUM, the actual increase in stool correction is only executed after the predetermined delay time C0TDLY, so the temperature of the exhaust gas rapidly rises to a high temperature. , and the knock level also overshoots to a large value. On the other hand, the 8th
Fig. B is a similar timing chart according to the present embodiment, but even if the weight increase correction cylinder value increases rapidly, the delay time C0TDLY changes when the ignition timing retard angle ωAsUM reaches the predetermined value C or more. Since the star increase correction is executed immediately without waiting for the elapse of time, the exhaust gas temperature and knock level are kept at stable values without overshooting.

Note that when the ignition timing retard amount is not large, the increase e correction is executed after the delay time C0TDLY as in the conventional case, so it goes without saying that it also has the effect of reducing the fuel temperature 91 and purifying the exhaust gas.

In the above embodiment, it was determined in step 714 whether the total corrected retard angle fiAsUM was equal to or greater than a predetermined value, but as is clear from the map of step 50B in FIG. 5, the corrected retard angle ff1AHOT due to the cooling water temperature Since the case is O, the determination in step 714 may be performed using the knocking correction retard angle IAKC8. At this time, the AKC8 performs step 5 of the flowchart in FIG.
Guarded by the maximum value AKC3MAX in 06,
Since it is not possible to take a value greater than that, the constant C used as the criterion in step 714 is naturally AK.
The value is below C3MAX.

Application of the present invention is not limited to engines equipped with a supercharger and a knock control device as in the above-mentioned embodiments.
It is clear that this method can be applied to any engine and has the effect of preventing an increase in exhaust gas.

[Effects of the Invention] According to the present invention, attention is paid to the amount of retardation of the ignition timing that has a large effect on the rise in exhaust gas temperature, and when the amount of retardation reaches a predetermined value or more, steps are immediately taken to prevent the exhaust gas temperature from rising□. By performing incremental correction of fuel injection M, a rapid rise in exhaust gas temperature is prevented.

This prevents deterioration of the exhaust pipe, exhaust gas purification device, etc. In particular, even if the internal combustion engine is equipped with a supercharging device, knocking control device, etc. and the exhaust gas temperature rises rapidly, it can sufficiently prevent the temperature rise. Protect from overheating.

In general, the increase in exhaust gas temperature due to an increase in ignition timing retardation is more rapid than the increase in exhaust gas temperature due to an increase in rotational speed or load, so this is especially true for internal combustion engines equipped with turbochargers, knock control devices, etc. 11 at the time of ignition according to the present invention
11 Judgment based on the amount of retardation is the load.

It becomes possible to set a more optimal execution point for increase correction without being influenced by consideration of other factors such as rotational speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the outline of the present invention, FIG. 2A is a graph showing the relationship between ignition timing and output torque of the internal combustion engine, and FIG. 2B is a graph showing the relationship between ignition timing and the required amount of correction. Graph, FIG. 3 is a configuration diagram showing an overview of an engine, peripheral devices, and electric circuit according to an embodiment of the present invention, FIG. 4A is a flowchart of a routine that performs peak hold start processing, and FIG. 4B is a knocking frequency calculation routine. FIG. 5 is a flowchart of the ignition timing calculation routine, FIG. 6 is a timing chart showing the ignition timing, FIG. 7 is a flowchart of the fuel 1 injection port calculation routine, and FIGS. 8A and 8B are the flowchart of the ignition timing calculation routine. These are timing charts I. showing the changes in the knock level, ignition timing retardation {circle around (2)}, fuel increase correction value, and exhaust gas temperature, respectively, according to the prior art and the embodiment of the present invention. 1... Engine body 5.6... Crank angle sensor 9... Spark plug 10... Control circuit 11... Fuel injection valve 14... Knock sensor 16... Turbocharger 18... Three-way catalyst device

Claims (1)

[Scope of Claims] 1. An ignition timing retard amount calculation means for calculating an ignition timing retard amount according to the operating state of the internal combustion engine, and a fuel increase correction for preventing a rise in exhaust gas temperature in accordance with at least the ignition timing retard amount. A fuel injection amount control device comprising a correction value calculation means for calculating a value, and a delay correction execution means for correcting the actual fuel injection amount using the fuel increase correction value after a predetermined delay time, the delay correction execution means A fuel injection amount control device comprising: an immediate execution section that immediately performs the correction when the ignition timing retard amount exceeds a predetermined value.