JP4777919B2 - Fuel control device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel control device for an internal combustion engine.

  The fuel evaporation characteristics of internal combustion engines vary, and when starting with heavy gasoline that does not easily evaporate during cold start, a large amount of fuel adheres to the intake port wall surface and intake valve, so the air-fuel mixture in the cylinder becomes lean and burns As a result, the amount of unburned gas increases and rotation fluctuations are likely to occur. In addition, the air-fuel mixture in the cylinder may become lean due to variations in characteristics of components such as a fuel injection valve, an air flow meter that measures the amount of air, or an intake pipe pressure sensor, resulting in rotational fluctuations as described above.

  By the way, the oxygen concentration sensor is not activated for ten seconds after the cold start, and the fuel injection amount cannot be controlled by detecting the air-fuel ratio.

  For this reason, the lean state of the air-fuel ratio caused by variations in fuel properties and component characteristics is detected from the rotation fluctuation after startup, and the fuel injection amount is controlled according to the rotation fluctuation amount to prevent over leaning. The technique made to do this is disclosed in Patent Document 1. In Patent Document 1, the amount of change in the rotational angular velocity between cylinders is integrated for a predetermined cycle, and the combustion stability index is used to control the fuel injection amount to increase or decrease in accordance with this stability index.

Japanese Patent No. 3591001

  However, in the technique disclosed in Patent Document 1, the fuel injection amount is adjusted according to the stability index obtained by integrating the rotation fluctuation amount (change amount of the rotational angular velocity between cylinders) for a predetermined number of explosions. If the air-fuel ratio rapidly leans after starting at cold start, etc., even if the rotational fluctuation amount increases, the integrated stability index including the rotational fluctuation amount calculated in the previous explosion stroke is Since it does not increase immediately, the detection of the lean state is delayed, and the correction of fuel increase is delayed, resulting in overlean, the combustion state deteriorates, and unburned gas may be discharged in large quantities or rotation fluctuations may occur. .

  Therefore, the present inventors conducted an experiment and examined the amount of rotational fluctuation for each explosion relative to the air-fuel ratio (the amount of change in crank angular speed between cylinders). FIG. 11 shows the rotational fluctuation amount (change amount of crank angular speed between cylinders) for each explosion with respect to the air-fuel ratio. Even if the air-fuel ratio is the same, the rotational fluctuation amount varies for each explosion. For this reason, in the prior art such as Patent Document 1, the lean state of the air-fuel ratio is detected by the value obtained by integrating or averaging the rotational fluctuation amount by a predetermined number of explosions, and the fuel injection amount is increased.

  Here, in order to improve startability generally, a large amount of fuel is injected during start-up (during cranking). At this time, the light component of the fuel adhering to the wall surface of the intake port is immediately after start-up (after rotation rise) As the intake pipe pressure decreases, it evaporates and flows into the cylinder and becomes rich in the air-fuel ratio temporarily. Thereafter, the air-fuel ratio changes to lean as the adhered fuel decreases. In particular, since gasoline with a high degree of heaviness has a small proportion of light components that easily evaporate, the fuel that evaporates immediately after start-up and flows into the cylinder decreases, and the air-fuel ratio of the cylinder rapidly changes in the lean direction. Therefore, it is required to quickly detect the lean state of the air-fuel ratio and increase the fuel injection amount.

  However, in the prior art such as Patent Document 1, as described above, a value obtained by integrating the rotation fluctuation amount by a predetermined number of explosions or rotation fluctuation in order to ensure the detection accuracy of the air-fuel ratio with respect to the fluctuation in rotation fluctuation amount for each explosion. The fuel injection amount is increased according to the value obtained by averaging the amount by the number of explosions. For this reason, when the air-fuel ratio suddenly changes to lean, such as when starting with high-grade gasoline as described above, the integrated value (or average value) of the rotational fluctuation immediately increases even if the rotational fluctuation increases. However, since the detection of the lean state is delayed, the correction for increasing the amount of fuel is delayed and the engine becomes overlean, and a large amount of unburned gas (HC) may be discharged or rotation may be lost.

  FIG. 12 shows the frequency distribution of the rotational fluctuation when the air-fuel ratio is stoichiometric (air-fuel ratio 14.5) and lean (air-fuel ratio 16). When the air-fuel ratio stoichiometric is lean, the ratio of a large amount of rotational fluctuation increases. From this, it is considered that the probability that the air-fuel ratio is lean is high when the rotational fluctuation amount is large. As an example, when the rotational fluctuation amount is equal to or greater than a predetermined threshold value SLDN in this frequency distribution, the frequency (probability) that the air-fuel ratio is less than or equal to stoichiometric is low, the probability that the air-fuel ratio is lean to 16 or more is high, When the rotational fluctuation amount is less than the predetermined threshold value SLDN, it can be seen that there is no great difference in the probability between the lean state and the stoichiometric to rich state.

  The present invention has been made on the basis of these findings, and in the fuel control device of an internal combustion engine, even when the air-fuel ratio is rapidly leaned, such as when starting with high-grade gasoline when cold, By quickly detecting the lean state and controlling the fuel injection amount to a high response, the air-fuel ratio is prevented from leaning beyond the stable combustion limit, preventing an increase in unburned gas emissions and rotation fluctuations. The purpose is to do.

In order to achieve the above object, a fuel control device for an internal combustion engine according to the present invention includes an intake port of each cylinder or a fuel injection valve provided in each cylinder, and an ignition plug provided in each cylinder. A fuel control device for an internal combustion engine, wherein a rotational fluctuation amount calculating means for calculating a rotational fluctuation amount between each cylinder due to ignition of the ignition plug for each cylinder in an ignition cycle, and an integration number of the rotational fluctuation amount are set. An integration number setting means; and a fuel correction means for correcting the fuel injection amount of the fuel injection valve, the control device of the internal combustion engine after the start, the calculated rotational fluctuation amount and the set integration number that said calculating an integrated value and / or the average value of the rotation fluctuation amount obtained from, depending on the magnitude of the integrated value and / or the average value of the rotation fluctuation amount, it corrects the fuel injection amount of the fuel injection valve And the integration Number setting means is characterized by changing the integration count to the set in accordance with the rotational fluctuation amount in the range of more than one.

The integration number setting means of the fuel control apparatus for an internal combustion engine according to the present invention, prior Symbol rotation fluctuation amount is characterized in that to reduce the cumulative number of times of the set to be larger than a predetermined threshold.

  The present invention detects the lean state of the air-fuel ratio after starting due to variations in fuel properties and component characteristics based on an integrated value obtained by integrating the rotational fluctuation amount for each ignition cycle by a set number of times, and the integrated value of the rotational fluctuation amount The air-fuel ratio control at the time of cold start can be performed by controlling the fuel injection amount according to the above. Further, according to the present invention, when the rotational fluctuation amount for each ignition cycle becomes large, the integrated value of the rotational fluctuation amount is immediately calculated by reducing the number of times of setting of the rotational fluctuation amount integrated by the integrating means, and the lean ratio of the air-fuel ratio is promptly calculated. A state is detected, and the fuel injection amount is increased and corrected according to the integrated value, thereby preventing overleaning.

Further, the fuel control apparatus for an internal combustion engine according to the present invention includes an integrating unit that integrates the rotation fluctuation amount for the set number of times of integration, and a normal that calculates an average value of the rotation fluctuation amount from the integrated value of the rotation fluctuation amount. Rise means, and weighted average calculation means for calculating an average value of the rotational fluctuation amounts of the set number of times by a weighted average .

Furthermore, the fuel control device for an internal combustion engine according to the present invention is characterized by comprising an integrating means for integrating the integrated value of the rotational fluctuation amount .

  The present invention detects the lean state of the air-fuel ratio after starting due to variations in fuel properties and component characteristics based on the average value of the rotational fluctuation amount in the set number of times, and the fuel injection amount in accordance with the average value of the rotational fluctuation amount By controlling this, it is possible to perform air-fuel ratio control when starting the cold machine. Further, according to the present invention, when the rotational fluctuation amount for each ignition cycle becomes large, the average value is calculated by the average value calculating means, the number of times of setting the rotational fluctuation amount is decreased, the average value is increased, and the lean state is detected quickly. Then, the fuel injection amount can be corrected to be increased according to the average value to prevent over leaning.

  The present invention detects the lean state of the air-fuel ratio after starting due to variations in fuel properties and component characteristics based on an integrated value obtained by multiplying the rotation fluctuation amount for each ignition cycle by a predetermined weighting factor and integrating the accumulated value. By controlling the fuel injection amount according to the value, the air-fuel ratio control at the time of cold start can be performed. Further, according to the present invention, when the rotational fluctuation amount for each ignition cycle becomes large, a predetermined weight coefficient applied to the rotational fluctuation amount is increased to increase the integrated value, and the lean state of the air-fuel ratio is promptly detected. It is possible to prevent overleaning by increasing the fuel injection amount in accordance with the value.

  According to the present invention, even when the air-fuel ratio rapidly leans due to the use of heavy gasoline after cold start, the lean state is detected quickly, and the fuel injection amount is controlled to be highly responsive, thereby preventing unburned fuel. Increase in gas (HC) emission and rotation fluctuation can be prevented.

  Hereinafter, an embodiment of a combustion control apparatus for an internal combustion engine according to the present invention will be described in detail with reference to FIGS. FIG. 1 shows the overall configuration of an engine control system including a combustion control device for an internal combustion engine according to the present invention.

  The engine is provided with a cooling water temperature sensor 21 that detects the temperature of the cooling water of the engine. A crank angle detection plate 29 is attached to the crankshaft 11 and a crank angle sensor 12 is provided. The intake pipe 7 constituting the intake system of the engine is provided with an intake pipe pressure sensor 13 for detecting the pressure of intake air, and a throttle valve 6 for controlling the intake air amount of the engine. A fuel injection valve 8 is provided.

  The intake air passes through the intake manifold 22 and the intake port 10, passes through the intake valve 9 as an air-fuel mixture, and is sucked into the combustion chamber 18 in the cylinder 19. A spark spark is generated from the spark plug 15 by the current from the ignition coil 14. Generated and burned. The combusted air-fuel mixture becomes exhaust gas and is discharged from the combustion chamber 18 when the engine exhaust valve is opened. In the exhaust system of the engine, an oxygen concentration sensor 20 is provided before the catalyst of the exhaust pipe 16.

  The controller 24 includes a CPU 25, a read only memory (ROM) 26 in which a control program and control data are stored, a writable memory (RAM) 27 in which control variables and the like are stored, and an input / output circuit 28. Yes. Signals from the crank angle sensor 12, the intake pipe pressure sensor 13, the oxygen concentration sensor 20, the cooling water temperature sensor 21, etc. are input to a controller (control device) 24, and the controller 24 receives the fuel injection amount, ignition timing, The throttle opening and the like are calculated, and control signals are output to the fuel injection valve 8, the ignition coil 14, the throttle valve 6 and the like, respectively.

FIG. 2 shows a control configuration block of a fuel control apparatus for an internal combustion engine according to the present invention. The rotational fluctuation calculating means 1 calculates the rotational fluctuation amount between cylinders (the amount of change in the crank angular speed of the current explosion cylinder relative to the crank angular speed of the previous explosion cylinder). the time T _n which is displaced between the crank angle _{(corresponding} to the inverse of the crank angular speed) is measured for each cylinder, the difference between the displacement time T _n-1 in the displacement time T _n and the previous explosion in this blast The rotational fluctuation amount DN is used, and the rotational fluctuation amount DN is calculated in synchronization with the explosion cycle of each cylinder.

  The number-of-integration setting means 2 sets the number NADD of rotation fluctuation amounts integrated by the integration means 3 in accordance with the rotation fluctuation amount DN calculated by the rotation fluctuation calculation means 1. In this embodiment, FIG. As shown, when the rotational fluctuation amount DN is less than or equal to a predetermined threshold value SLDN, the number of integrations is 20 times, and when the rotational fluctuation amount DN exceeds the predetermined threshold value SLDN, the number of integration times is one. In the present embodiment, the integration number NADD set by the integration number setting means 2 is set to 20 and 1, but this number is not limited to this and may be set as appropriate.

  The integrating means 3 has a memory for storing the past 20 rotational fluctuation amounts, and the rotational fluctuation amount DN calculated by the rotational fluctuation calculating means 1 is calculated by the cumulative number NADD set by the cumulative number setting means 2. The integrated value IDN is calculated by integration and output to the normalizing means 4.

  The normalizing means 4 divides the rotational fluctuation amount integrated value IDN calculated by the integrating means 3 by the number of explosions to obtain an average value IXDN of rotational fluctuations per number of explosions.

  The fuel correction means 5 stores in a memory a table in which an increase correction step FSTPA with respect to the average value IXDN of the rotational fluctuation amount as shown in FIG. 4 is preset, and the average of the rotational fluctuation amounts calculated by the normalizing means 4 The value IXDN is compared with the judgment level SLIXDN, and when the average value IXDN of the rotational fluctuation is equal to or higher than the judgment level SLIXDN, an increase correction step FSTPA corresponding to the magnitude of the average value IXDN is obtained from the table, and at the increase correction step FSTPA If the fuel injection amount is increased and corrected, and if the average value IXDN of the rotational fluctuation is less than the judgment level SLIXDN, it is considered that the air-fuel ratio is in the stoichiometric to rich state, and the fuel correction coefficient FTRM is reduced to the predetermined value by the decrease correction step FSTPD. Reduce the fuel injection amount.

  Next, the fuel control operation in the internal combustion engine fuel control apparatus of the present embodiment will be described in detail with reference to the flowchart of FIG.

  In step 100, it is determined whether or not the engine temperature (cooling water temperature or the like) is in a cold state of a predetermined value TWSL or less, and in step 110, it is determined whether or not the oxygen concentration sensor 20 after startup is not activated. To do. If the engine temperature (cooling water temperature or the like) is higher than a predetermined value TWSL, or if the oxygen concentration sensor 20 is activated and can be detected, air-fuel ratio control based on rotational fluctuation is not necessary. If both step 100 and step 110 are established, the routine proceeds to step 120, where the rotational fluctuation amount DN (the amount of change in the crank angular velocity of the current explosion cylinder with respect to the crank angular velocity of the previous explosion cylinder) is calculated.

  Steps 130, 140, and 150 are processes for setting the number NADD of rotational fluctuation amounts. In step 130, it is determined whether or not the rotational fluctuation amount DN is equal to or greater than a predetermined threshold value SLDN. If the rotational fluctuation amount DN is less than the predetermined threshold value SLDN, the process proceeds to step 140, and the cumulative number NADD is set to 20. If the rotational fluctuation amount DN is equal to or greater than a predetermined threshold value SLDN, the process proceeds to step 150, and the integration number NADD is set to one.

  Next, at step 160, an average value IXDN of the rotational fluctuation amount for controlling the fuel injection amount is calculated. Integration is performed by integrating the past NADD rotation fluctuation amounts including the current explosion according to the integration number NADD set in the previous step, and dividing by the integration number NADD to calculate an average value IXDN of the rotation fluctuation amount.

  In step 170, the average value IXDN of the rotational fluctuation amount is compared with a predetermined judgment level SLIXDN. If the average value IXDN is equal to or higher than the judgment level SLIXDN, the air-fuel ratio is considered to be lean. The increase correction step FSTPA corresponding to the value IXDN is obtained from the table of FIG. 4, and the increase correction step FSTPA is added to the fuel correction coefficient FTRM based on the rotational fluctuation amount. If the integrated value IXDN is less than the judgment level SLIXDN in step 170, it is considered that the air-fuel ratio is in a stoichiometric to rich state, and in step 190, the predetermined amount of decrease correction step FSTPD is subtracted from the fuel correction coefficient FTRM, thereby evaporating. It is possible to prevent a large amount of unburned gas from being discharged due to the rich air-fuel ratio when using light gasoline, which is easy to do.

  Next, at step 200, the output pulse width to the fuel injection valve is calculated. For the basic injection pulse width TP calculated from the intake air amount calculated from the intake pipe pressure sensor signal, etc., in addition to the correction by the fuel correction coefficient FTRM by the rotational fluctuation DN, the correction by the conventional correction coefficient FTW by the coolant temperature, etc. Is the output pulse width TI.

  FIG. 6 shows the engine speed, the air-fuel ratio, the average value of the rotational fluctuation amount, and the fuel injection amount when the engine is started by the fuel control device for the internal combustion engine of the present embodiment. Here, the solid line indicates the air-fuel ratio and the fuel injection amount in the fuel control device of the present embodiment, and the dotted line indicates the air-fuel ratio and the fuel injection amount in the fuel control device in which the conventional number of integrations is fixed to several tens of times. .

  When the air-fuel ratio suddenly changes in the lean direction after startup and the rotational fluctuation DN is equal to or greater than the predetermined threshold SLDN, the average value IXDN of one explosion is calculated, and the rotational fluctuation DN is the predetermined threshold SLDN. If the above situation occurs once, the lean state is immediately detected, and the fuel correction means 5 promptly increases the amount of fuel indicated by the increase correction step FSTPA.

  Further, when the average value IXDN of the rotational fluctuation amount of 20 times of accumulation is equal to or higher than the predetermined level SLIXDN, the fuel injection amount is increased and corrected in the increase correction step FSTPA corresponding to the magnitude of the average value IXDN of the rotational fluctuation amount. When the average value IXDN of the rotational fluctuation amount is less than the predetermined level SLIXDN, the fuel injection amount is reduced and corrected by a predetermined amount of reduction correction step FSTPD assuming that the air-fuel ratio is in a stoichiometric to rich state.

  In the present embodiment, if there is one occurrence of the rotational fluctuation amount DN equal to or greater than the predetermined threshold value SLDN, the lean state is immediately detected and the injected fuel is increased, so that overleaning can be prevented and combustion is performed. There will be no problems such as deterioration or drop in rotation.

  FIG. 7 shows another embodiment of the control configuration block in the fuel control device of the internal combustion engine, in which the integrating means 3 and the normalizing means 4 in the embodiment described in FIG. The rotation fluctuation calculating means 1, the cumulative number setting means 2 and the fuel correcting means 5 are the same as those in the above embodiment.

The weighted average calculation means 6 calculates the rotation fluctuation amount average value IXDN _n by the following equation (1).
IXDN _n = KW * (DN−IXDN _n−1 ) + IXDN _n−1 (1)
KW = 1 / NADD
IXDN _n : Average value of rotational fluctuation
IXDN _n-1 : Average value of previous rotation fluctuation
KW: Average weighting factor
NADD: Integration count

  Here, as shown in FIG. 8, when the rotational fluctuation amount DN is equal to or less than a predetermined threshold SLDN, the cumulative number setting means 2 sets the cumulative number of times 20 times (KW = 1/20), and the rotational fluctuation amount DN is When the predetermined threshold value SLDN is exceeded, the number of times of integration (KW = 1) is set. When the integration number NADD is set to one, the rotation fluctuation average value IXDN coincides with the rotation fluctuation DN.

  When calculating the rotational fluctuation average value IXDN by the weighted average calculation, the weighted average calculation is performed for each integration number, and the weighted average calculation corresponding to the integration number is performed according to the calculated integration number. Try to select a result.

  In this embodiment, if one occurrence of the rotational fluctuation amount DN is equal to or greater than the predetermined threshold value SLDN occurs once, the averaging weight coefficient KW is set to 1, and the rotational fluctuation amount average value IXDN becomes the predetermined threshold value SLIXDN. As described above, the lean state is immediately detected, and the fuel correction means 8 promptly increases the amount of fuel in the increase correction step FSTPA corresponding to the rotational fluctuation average value IXDN. And troubles such as falling off the rotation.

  In this embodiment, since the rotation fluctuation amount can be integrated and averaged simultaneously, memory can be saved.

  FIG. 9 shows another embodiment of the control configuration block in the fuel control apparatus for an internal combustion engine. The integration method is different from the integration means 3 in the embodiment described in FIG. 2, and the normalizing means 4 is not provided. The rotation fluctuation calculating means 1 and the cumulative number setting means 2 are the same as those in the embodiment described with reference to FIG.

The integrating means 7 has a memory for storing the past 20 rotational fluctuation amounts, and integrates the rotational fluctuation amount calculated by the rotational fluctuation calculating means 1 by the cumulative number set by the cumulative number setting means 2. The integrated value is output to the fuel correction means 8. When the integration number setting unit 2 sets the number of integrations to 20, the integration unit 7 stores the rotation variation amounts DN _{n-20 to} DN _{n-1 in} the memory and integrates them, and the fuel correction unit Then, the rotational fluctuation amount DN _{n to} DN _{n + 19} is stored again in the memory, integrated, and output to the fuel correction means 8. When the rotational fluctuation amount DN exceeds the predetermined threshold value SLDN while the rotational fluctuation amount is integrated 20 times by the integration number setting means 2, the integration is stopped 20 times when the integration number is set to 1 Then, the rotational fluctuation amount is integrated once and output to the fuel correction means 8.

As shown in FIG. 10, the fuel correction means 8 has a one-time integration table in which an increase correction step FSTPA for the integrated value IDN when the rotational variation DN is integrated once and a rotational variation amount DN of 20 are set. A 20 times integration table in which an increase correction step FSTPA for the integration value IDN at the time of integration is preset is stored in the memory. When the rotational fluctuation amount DN is greater than or equal to the determination level SLDN, the fuel correction means 8 compares the rotational fluctuation amount once with the integrated value IDN (same as the rotational fluctuation amount DN) with the determination level SLIDN, and calculates the rotational fluctuation amount. When the integrated value IDN is equal to or higher than the determination level SLIDN, an increase correction step FSTPA corresponding to the magnitude of the integrated value IDN is obtained using a one-time integration table, and the fuel injection amount is increased and corrected at the increase correction step FSTPA. Further, when the rotational fluctuation amount DN is less than the determination level SLDN, the fuel correction unit 8 compares the integrated value IDN obtained by integrating the rotational fluctuation amount 20 times with the determination level SLIDN, and the integrated value obtained by integrating the rotational fluctuation amount 20 times. When the IDN is equal to or higher than the determination level SLIDN, an increase correction step FSTPA corresponding to the magnitude of the integrated value IDN obtained by integrating the rotational fluctuation amount 20 times using the 20-time integration table is obtained, and the fuel injection amount at the increase correction step FSTPA Correct the increase.
If the integrated value IDN obtained by integrating the rotational fluctuation amount 20 times is less than the determination level SLIDN, the air-fuel ratio is assumed to be in a stoichiometric to rich state, and the fuel injection amount is corrected to decrease by a predetermined value decreasing correction step FSTPD.

  In the present embodiment, when one occurrence of the rotational fluctuation amount exceeding the predetermined threshold value SLDN occurs once, the lean state is immediately detected, and the fuel correction means 5 increases the fuel in the increase correction step FSTPA corresponding to the rotational fluctuation amount. Since the increase in the amount is promptly implemented, overleaning can be prevented, and problems such as deterioration in combustion and drop in rotation do not occur.

  As described above, in the combustion control device for an internal combustion engine according to the present invention, the correction of the fuel injection amount is performed based on the integrated value of the rotational fluctuation amount after the cold start, and the generation of the rotational fluctuation amount in the rich state and the lean state is generated. By taking into account the difference in frequency distribution and changing the number of times to integrate the rotational fluctuation amount according to the rotational fluctuation amount, the lean state is detected quickly and the fuel injection amount is increased. And this can prevent the increase in HC emissions and rotation fluctuation. Further, in the combustion control device for an internal combustion engine according to the present invention, when the rotational fluctuation amount DN is less than the predetermined threshold value SLDN, there is a large difference in the probability between the lean state and the stoichiometric to rich state. Therefore, the fuel injection amount is increased by detecting the lean state with a higher probability than the value obtained by averaging the rotational fluctuation amount in the past several tens of explosions including this explosion.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. Moreover, each component is not limited to the said structure, unless the characteristic function of this invention is impaired. In the above-described embodiment, a port injection engine is used. However, even in a cylinder injection engine, when heavy gasoline is used, the ratio of fuel adhering to the cylinder wall surface increases, and the air-fuel mixture around the spark plug becomes lean. Since the combustion may deteriorate as in the case of the port injection engine, the control method of the present invention is not limited to the port injection engine having the injector in the intake port, but the cylinder having the fuel injection valve in each cylinder. You may apply to an internal injection type engine.

1 is an overall configuration diagram of an engine control system including a combustion control device for an internal combustion engine according to the present invention. The figure which shows one Embodiment of the control structure block in the fuel control apparatus of the internal combustion engine which concerns on this invention. The figure which shows the relationship between the rotation fluctuation amount in the integration frequency setting means 2 of this embodiment, and the integration frequency. The figure which shows the relationship between the average value of the rotation fluctuation amount in the fuel correction | amendment means 5 of this embodiment, and a fuel increase step. The flowchart of the operation | movement of the fuel control in embodiment of the combustion control apparatus of the internal combustion engine which concerns on this invention. The figure which shows the engine speed at the time of engine starting by the fuel control apparatus of the internal combustion engine of this embodiment, an air fuel ratio, the average value of a rotation fluctuation amount, and fuel injection amount. The figure which shows other embodiment of the control structure block in the fuel control apparatus of the internal combustion engine which concerns on this invention. The figure which shows other embodiment of the control structure block in the fuel control apparatus of the internal combustion engine which concerns on this invention. The figure which shows other embodiment of the control structure block in the fuel control apparatus of the internal combustion engine which concerns on this invention. The figure which shows the relationship between the average value of the rotation fluctuation amount in the fuel correction means 8 of this embodiment, and a fuel increase step. The figure which shows the relationship between the air fuel ratio in an internal combustion engine, and a rotation fluctuation amount. The figure which shows the relationship between the air-fuel ratio in an internal combustion engine, and the generation frequency distribution of rotation fluctuation amount.

Explanation of symbols

7 Intake pipe 8 Fuel injection valve 12 Crank angle sensor 20 Oxygen concentration sensor 21 Cooling water temperature sensor 24 Controller (control device)
29 Crank angle detection plate

Claims (5)

A fuel control device for an internal combustion engine, comprising: an intake port of each cylinder or a fuel injection valve provided in each cylinder; and an ignition plug provided in each cylinder,
Rotational fluctuation amount calculating means for calculating the rotational fluctuation amount between the cylinders due to ignition of the ignition plug for each cylinder in the ignition cycle, cumulative number setting means for setting the cumulative number of the rotational fluctuation amounts, and the fuel injection valve Fuel correction means for correcting the fuel injection amount of
The control device for the internal combustion engine calculates an integrated value and / or an average value of the rotational fluctuation amount obtained from the calculated rotational fluctuation amount and the set number of integrations after starting, and integrates the rotational fluctuation amount The fuel injection amount of the fuel injection valve is corrected according to the value and / or the average value .
The fuel control device for an internal combustion engine, wherein the cumulative number setting means changes the set cumulative number within a range of one or more according to the rotation fluctuation amount . 2. The fuel control device for an internal combustion engine according to claim 1 , wherein the cumulative number setting means decreases the cumulative number to be set when the rotation fluctuation amount exceeds a predetermined threshold value. The fuel control device includes integration means for integrating the rotation fluctuation amount for the set number of integrations, and normalizing means for calculating an average value of the rotation fluctuation amount from the integrated value of the rotation fluctuation amount. The fuel control apparatus for an internal combustion engine according to claim 1 or 2 , 3. The fuel for an internal combustion engine according to claim 1, wherein the fuel control device includes weighted average calculation means for calculating an average value of the rotational fluctuation amounts of the set number of integrations by a weighted average. 4. Control device. The fuel control apparatus for an internal combustion engine according to claim 1 or 2 , wherein the fuel control apparatus includes an integration unit that integrates an integrated value of the rotation fluctuation amount.

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