JPH04134143A - Fuel injection quantity controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To obviate any surge from occurring by judging of whether relations between a fuel sticking compensation value and a load variation is within a dead zone or not, and when the judged result is within the dead zone, prohibiting any compensation for a fundamental injection quantity by means of the fuel sticking compensation value. CONSTITUTION:In a device which operates a fuel sticking quantity in an intake system M2 in succession on the basis of intake quantity equivalent and engine speed with a sticking quantity operational means M6, while operates a fuel sticking compensation value on the basis of a difference between this time operated fuel sticking quantity and the last fuel sticking quantity with a sticking compensation value operational means M7, and also operates the fuel injection quantity by way of compensating the fundamental injection quantity by this fuel sticking compensation value with a injection quantity operational means M8, a load variation in an internal combustion engine M1 is detected by a load variation operational means M9, while a load variation at each time is operated with a load variation operational means M10. In addition, whether relations between the fuel sticking compensation value and the load variation is within a dead zone or not is judged by a dead zone judging means M11. When it is not within the dead zone, compensation for the fundamental injection quantity by means of the fuel sticking compensation value is allowed, while when it is within the dead zone, any compensation for the fundamental injection quantity by means of the fuel sticking compensation value is prohibited.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a fuel injection amount control device for an internal combustion engine, and more specifically, a device for controlling the amount of fuel injected into an internal combustion engine. The present invention relates to a fuel injection amount control device for an internal combustion engine that controls the amount of fuel injection.

[Prior Art] Conventionally, when an internal combustion engine is in operation, fuel supplied to the intake system adheres to a wall surface of a passageway of the intake system, or the adhering fuel evaporates. Therefore, in a control device that controls the fuel injection amount in the intake system, the required fuel injection amount is determined while correcting the amount of fuel adhering to the passage wall surface of the intake system and its evaporation amount. .

For example, the technology disclosed in Japanese Patent Application Laid-Open No. 63-215848 is designed to correct disturbances in the air-fuel ratio caused by fuel adhering to the wall surface of the passage in the intake system, especially during transient operation when the throttle opening changes. Then, based on the detected values of throttle opening and engine speed detected by each sensor, the theoretical intake pressure at steady state is calculated, and the amount of fuel deposited in the intake system is calculated based on the theoretical intake pressure. The change in is calculated. Then, the amount of change in the fuel adhesion amount is set as the fuel adhesion correction amount, and the basic injection amount is corrected by the correction amount to determine the required fuel injection amount.

[Problems to be Solved by the Invention] However, in the technique of the above publication, in the low load operating range and low rotational speed operating range of the internal combustion engine, minute load fluctuations (for example, minute fluctuations in throttle opening) and minute rotational speed fluctuations occur. Also for
The fuel adhesion correction amount is calculated with high sensitivity, and the correction amount is reflected in the fuel injection amount. Therefore, in low-load operating ranges and low-speed operating ranges, even during slow acceleration or steady state where the throttle opening changes only gradually, fluctuations (periodic fluctuations) in the fuel injection amount occur due to the fuel adhesion correction amount. There was a risk. As a result, a problem arises in that acceleration surges and steady surges occur, leading to deterioration of drivability.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reliably correct the amount of fuel adhering to the intake system during transient operation with a large rate of load change, and to correct the amount of fuel deposited in the intake system during steady state operations with a small rate of load change. An object of the present invention is to provide a fuel injection amount control device for an internal combustion engine that can prevent surges by canceling correction of the amount of fuel deposited in an intake system.

Means for Solving the Problems] In order to achieve the above object, in the present invention, as shown in FIG. An intake air amount equivalent value measuring means M4 that measures the intake air amount equivalent value in system M2, an engine speed detecting means M5 that detects the rotation speed of the internal combustion engine M1, and the measured intake air amount equivalent value and the detected internal combustion engine M1. The adhering amount calculating means M6 sequentially calculates the amount of fuel adhering to the intake system M2 in a steady state based on the rotational speed of Adhesion correction amount calculation means M7 for calculating the adhesion correction amount; and injection amount calculation means M8 for calculating the required fuel injection amount from the fuel injection means M3 by correcting the basic injection amount based on the calculated fuel adhesion correction amount. In the fuel injection amount control device for an internal combustion engine, the device includes a load change detection means M9 that detects a load change of the internal combustion engine M1, and a load change rate that calculates a load change rate at each time based on the detected load change. The calculation means MIO determines whether the relationship between the calculated fuel adhesion correction amount and the calculated load change rate is within a dead band that is defined in advance as a relationship between the fuel adhesion correction amount that is inversely proportional to the magnitude of the load change rate. If the result of the determination is not within the dead zone, correction of the basic injection amount by the fuel adhesion correction amount in the injection amount calculation means M8 is permitted, and if the result of determination is within the dead zone, for,
A correction control means M12 is provided for prohibiting correction of the basic injection amount by the fuel adhesion correction amount in the injection amount calculation means M8.

[Operation] According to the above configuration, as shown in FIG.
During operation 1, the intake air amount equivalent value measuring means M4 measures the intake air amount equivalent value in the intake system M2, such as the intake air flow rate and intake pressure. Further, the engine rotation speed detection means M5 detects the internal combustion engine M.
1 rotation speed, that is, the engine rotation speed is detected.

Then, the adhesion amount calculating means M6 sequentially calculates the amount of fuel adhering to the intake system M2 in a steady state based on the measured intake air amount equivalent value and the detected engine speed. Further, the adhesion correction amount calculating means M7 calculates the fuel adhesion correction amount based on the difference between the currently calculated fuel adhesion amount and the previously calculated fuel adhesion amount.

In response to the above calculation result, the injection amount calculation means M8 corrects the basic injection amount using the calculated fuel adhesion correction amount, and calculates the required fuel injection amount from the fuel injection means M3. In other words, the fuel injection amount in the intake system M2 is controlled.

At this time, the load change detection means M9 detects the load change of the internal combustion engine M1. Further, the load change rate calculation means MIO calculates the load change rate at each time based on the detected load change. Then, the dead band determining means Mll determines that the relationship between the fuel adhesion correction amount calculated by the adhesion correction amount calculation means M7 and the load change rate calculated by the load change rate calculation means M10 is such that the load change rate is large. It is determined whether or not the relationship between the fuel adhesion correction amount, which is inversely proportional to the fuel adhesion correction amount, is within a predetermined dead zone.

Then, in response to the above judgment result, the correction control means M12
If the judgment result is not within the dead zone, the basic injection amount is allowed to be corrected by the fuel adhesion correction amount in the injection amount calculation means M8. On the other hand, if the determination result is within the dead band, the correction control means M12 prohibits the injection amount calculation means M8 from correcting the basic injection amount using the fuel adhesion correction amount.

Therefore, in the case of a transient operation with a large load change rate, the basic injection amount is corrected by the fuel adhesion correction amount to determine the fuel injection amount in the injection amount calculation means M8.

In other words, fuel injection control is performed in consideration of the amount of fuel deposited in the intake system M2.

On the other hand, in the case of normal operation with a small load change rate, the correction of the basic injection amount by the fuel adhesion correction amount is canceled in the injection amount calculation means M8. In other words, fuel injection amount control is performed that ignores the amount of fuel deposited in the intake system M2.

[Example] Hereinafter, an example embodying this invention is shown in Figs. 2 to 10.
This will be explained in detail based on the figures.

FIG. 2 is a schematic configuration diagram showing a gasoline engine system to which the fuel injection amount control device for an internal combustion engine according to the present invention is applied. An engine 1, which is an internal combustion engine mounted on a vehicle, includes an intake passage 2 that constitutes an intake system, and an exhaust passage 3 that constitutes an exhaust system. An air cleaner 4 is provided at the entrance of the intake passage 2. Further, a surge tank 5 is provided in the middle of the intake passage 2. On the downstream side of the surge tank 5, there are intake manifolds 2a, 2b, which communicate with each cylinder (four cylinders in this case) of the engine 1, respectively.
2c and 2d are provided. Furthermore, injectors 6A, 6B, and 6C as fuel injection means are provided near each of the intake manifolds 2a to 2d.

6D are provided respectively. On the other hand, a catalytic converter 7 having a built-in three-way catalyst is provided on the exit side of the exhaust passage 3.

The engine l takes in outside air from the air cleaner 4 through the intake passage 2. Further, at the same time as taking in the outside air, the engine 1 takes in fuel injected from each injector 6A to 6D. In addition, the engine 1 explodes and burns the mixture of the taken in fuel and outside air in each combustion chamber to obtain driving force, and then exhausts the exhaust gas from the exhaust passage 3 to the outside via the catalytic converter 7. do.

In this embodiment, the engine 1 is of an independent throttle type, and each intake manifold 2a to 2d downstream of the surge tank 5 has throttle valves 8A, 8B, 8C.
, 8D are provided respectively. Each of the throttle valves 8A to 8D is opened and closed in conjunction with the operation of an accelerator pedal (not shown). And each throttle valve 8A~8
By opening and closing D, each intake manifold t"2a~
The intake flow rate at 2d is adjusted.

A throttle opening sensor 21 is provided near the throttle valves 8A to 8D to detect their openings, that is, throttle openings TA. This throttle opening sensor 21
is the throttle opening T corresponding to the load change of the engine 1
It constitutes a load change detection means for detecting a change in A.

Further, on the upstream side of the surge tank 5, there is a well-known intake air amount equivalent value measuring means for measuring the actual intake air flow rate (intake air flow rate per second) GA as the intake air amount equivalent value passing through the intake passage 2. An air flow meter 22 is provided. In this embodiment, a movable vane type air flow meter 22 is used. Furthermore, an oxygen sensor 23 is provided in the middle of the exhaust passage 3 to detect the oxygen concentration in the exhaust gas, that is, to detect the exhaust air-fuel ratio in the exhaust passage 3. Further, the engine 1 is provided with a water temperature sensor 24 that detects the temperature of the cooling water (cooling water temperature) THW.

Spark plugs 9A, 9 provided for each cylinder of the engine 1
An ignition signal distributed by the distributor 10 is applied to B, 9C, and 9D. distributor 10
is for distributing the high voltage output from the igniter 11 to each of the spark plugs 9A to 9D in synchronization with the crank angle of the engine 1. And each spark plug 9A to 9D
The ignition timing is determined by the high voltage output timing from the igniter 11.

The distributor 10 includes a rotation speed sensor 25 as an engine rotation speed detection means for detecting the rotation speed (engine rotation speed) NE of the engine 1 from the rotation of the rotor (not shown).
Similarly, a cylinder discrimination sensor 26 is installed, which detects changes in the crank angle of the engine 1 at a predetermined rate according to the rotation of the rotor. In this embodiment, assuming that the engine 1 rotates twice per stroke, the cylinder discrimination sensor 26 detects the crank angle at a rate of 360° CA.

Further, a transmission (not shown) drivingly connected to the engine 1 is provided with a vehicle speed sensor 27 for detecting vehicle speed.

Then, each injector 6A to 6D and the equniter 11
are electrically connected to an electronic control unit (hereinafter simply referred to as rEcU) 30, and their drive timings are controlled by the operation of the ECU 30. This ECU 3O constitutes an adhesion amount calculation means, an adhesion correction amount calculation means, an injection amount calculation means, a load change rate calculation means, a dead band determination means, and a correction control means. Further, a throttle opening sensor 21, an air flow meter 22, an oxygen sensor 23, a water temperature sensor 24, a rotation speed sensor 25, a cylinder discrimination sensor 26, and a vehicle speed sensor 27 are connected to the ECU 30, respectively. and,
The ECU 30 suitably controls the injectors 6A to 6D and the igniter 11 based on output signals from the air flow meter 22 and each sensor 21, 23 to 27.

Next, the configuration of the ECU 3O will be explained according to the block diagram of FIG. 3. ECU3O is the central processing unit (CPU)
31, a read-only memory (ROM) 32 that stores predetermined control programs, etc., a random access memory (RAM) 33 that temporarily stores calculation results of the CPU 31, etc.;
Backup RAM 3 for storing pre-stored data
4, etc., and each of these parts is connected to an external input circuit 35, an external output circuit 36, etc. by a bus 37 as a logic operation circuit.

The external input circuit 35 is connected to the aforementioned throttle opening sensor 21, air flow meter 22, oxygen sensor 23, water temperature sensor 24, rotation speed sensor 25, cylinder discrimination sensor 26, vehicle speed sensor 27, and the like. and,
The CPU 31 reads output signals from the air flow meter 22 and each of the sensors 21, 23 to 27 as input values via the external input circuit 35.

Further, the CPU 31 suitably controls the injectors 6A to 6D and the igniter 11 connected to the external output circuit 36 based on these input values.

Next, the calculation process of the basic injection amount executed by the ECU 3O mentioned above will be explained according to the flowchart of FIG. 4. Incidentally, the routine of this flowchart is executed by a regular interrupt every predetermined time.

When the process moves to this routine, first step 101
In, the rotation speed sensor 25 and the air flow meter 22
Based on the detected values, the engine speed NE and the intake flow rate G8, which is the actual intake flow rate measurement value, are respectively taken in. Then, in step 102, the unit intake air flow rate GN per one revolution of the engine 1 is calculated from the engine speed NE and the intake air flow 11GA that have been taken in.

Next, in step 103, the unit intake flow rate GN is smoothed so as to gradually change according to the following equation (1), and the processing result is set as the smoothed measurement value GNSMl in the current processing cycle.

GNSMI←GNSMO+ (GN-GNSMO) *K
G1...(1) Here, GN
SMO is the smoothed measurement value in the previous processing cycle,
KGI is a predetermined smoothing coefficient to suppress pulsation of the unit intake flow rate GN.

Further, in step 104, based on the detected values of the rotational speed sensor 25 and the throttle opening sensor 21, the engine rotational speed NE and the throttle opening T'A are respectively taken.

Then, in step 105, a predetermined theoretical steady intake air flow rate GNTA is calculated from the taken-in engine speed NE and throttle opening TA. This steady intake air flow rate GNTA is determined according to a predetermined three-dimensional map (not shown) using the engine speed NE and throttle opening TA as parameters.

Next, in step 106, the steady intake flow rate GNTA is smoothed to gradually change according to the following equation (2), and the processing result is set as the smoothed theoretical value GNCRT1 in the current processing cycle.

GNCRT 1-GNCRTO+ (GNTAGNCR
TO) *KG2 ... (2) Here, G, NCRT
O is the annealed theoretical value in the previous processing cycle, and KG
2 is a predetermined smoothing coefficient. Also, the smoothed measurement value GNS
MI requires a filter that does not cause fluctuations (periodic fluctuations) in the unit intake flow rate GN. Therefore, as a filter for the annealed theoretical value GNCRT 1, the annealed measured value G
A smoothing coefficient KG2 is selected so that NSMI is approximately equal to the smoothed theoretical value GNCRT1.

Then, in step 107, the final intake flow rate (final intake flow rate) GNEND is calculated according to the following equation (3), and the result is set as the final intake flow rate GNEND in the current processing cycle.

GNEND 4-GNSMI + (GNTA-GNCRTI)... (3) That is, the difference between the steady intake flow rate GNTA and the annealed theoretical value GNCRTI is added to the annealed measured value GNSMI to determine the final intake flow rate GN.
Ask for END.

Thereafter, in step 108, the final intake flow rate GNE
A value obtained by multiplying ND by an injection constant KINJ determined in advance is determined as the basic injection amount TP, and the subsequent processing is temporarily terminated.

The basic injection amount TP is determined as described above.

In addition, the final intake flow rate GN used in the process described later
END is also required. Here, the final intake flow rate G
Regarding NEND, the calculation of the final intake flow rate GNEND during a transient operation such as when the throttle opening degree TA changes will be explained with reference to the time chart of FIG.

Now, as shown in Fig. 5(a), when the throttle opening TA rapidly increases and changes at time t1, the amount of air actually taken into each cylinder also changes as shown in Fig. 5(b). It increases and changes rapidly.

During a transient operation in which the throttle opening degree TA changes as described above, the unit intake flow rate GN determined based on the intake flow rate GA, which is the measured value of the air flow meter 22, is calculated as follows.
As shown in Figure (C), fluctuations (periodic fluctuations) may occur due to intake pulsation within the intake passage 2, fluctuations in the output of the air flow meter 22, and the like. Even if there is fluctuation in the unit intake flow rate GN, as shown in Fig. 5(b) and (c), the smoothed measured value GNSM obtained by the smoothing process of the value is Changes gradually and smoothly with a slight delay in response to changes in quantity.

On the other hand, as shown in Fig. 5(d), the steady intake flow rate GNTA determined by the engine speed NE and the throttle opening TA increases rapidly to approximate changes in the intake air amount to each cylinder. Change. Also, the steady intake flow rate G
Annealed theoretical value GNC obtained by annealing NTA
As shown in FIGS. 5(b) and 5(d), RT changes gradually and smoothly with a slight delay in the rise of the intake air amount to each cylinder.

Here, as described above, in step 106 of the flowchart of FIG. 4, the annealing coefficient K
G2 is selected. In addition, the shaded area in Fig. 4(d) is the steady intake flow rate GNTA and the annealed theoretical value GNCR.
This is the difference between T.

Then, as shown in FIG. 5(e), the final intake flow rate GN
END is the steady intake flow rate GNTA and the annealed theoretical value GNCR
The difference from T is obtained as a value added to the smoothed measurement value GNSM. Therefore, a final intake flow rate GNEND can be obtained in which fluctuations caused by intake pulsations in the intake passage 2, fluctuations in the output of the air flow meter 22, etc. are eliminated.

As described above, according to the fuel injection amount control device of this embodiment, even if the actual measurement value by the air flow meter 22 fluctuates due to intake pulsation in the intake passage 2, the The unit intake flow rate GN is smoothed. Therefore, it is possible to obtain a smoothed measurement value GNSM that gradually and smoothly changes by removing the influence of intake pulsation and the like.

In addition, if there is a difference in the amount of intake flow leakage that affects the amount of intake air to each cylinder due to product tolerances of each throttle valve 8A to 8D or changes over time, etc., the smoothed measured value GNSM The value changes depending on the amount of leakage, etc. On the other hand, the value of the difference between the theoretical steady intake flow rate GNTA obtained from the relationship between the throttle opening TA and the engine speed NE and the annealed theoretical value GNCRT obtained by the annealing process is the intake flow leakage value. It does not change depending on the amount etc. Therefore, steady intake flow rate GN
Final intake flow rate GNE obtained by adding the difference between TA and the annealed theoretical value GNCRT and the annealed measured value GNSM
ND is a value that reflects the intake air flow leakage amount. In other words, if the amount of air actually taken into each cylinder differs from the theoretical steady intake flow rate GNTA due to the product tolerance of each throttle valve 8A to 8D or its change over time, Final intake flow rate GNEND, actual intake flow rate GA
, the steady intake flow rate GNTA are never equal, and the final intake flow rate GNE reflects the difference in intake flow leakage amount.
It is possible to get an ND.

In other words, an appropriate final intake flow rate GNEND can always be obtained in accordance with product variations in the throttle valves 8A to 8D and differences in the intake flow rate GA due to changes over time. Then, by using the appropriate final intake flow rate GNEND, an appropriate basic injection amount TP can always be obtained.

In addition, in this embodiment, throttle valves 8A to 8D are provided for each cylinder downstream of the surge tank 5. Therefore, when the engine I is operating, the amount of air taken into each cylinder is approximately equal to the actual intake flow rate passing through each throttle valve 8A to 8D, and there is a first-order lag in the intake flow rate GA measured by the air flow meter 22. It will never occur. For this reason, during normal operation when the opening changes of the throttle valves 8A to 8D are small, the air flow meter 2
The intake air flow rate GA measured in step 2 can be used as is for calculating the basic injection amount TP.

Next, fuel injection amount control performed using the basic injection amount TP and final intake flow rate GNEND determined in the flowchart of FIG. 4 will be explained according to the flowchart of FIG. 6. Incidentally, the routine of this flowchart is executed by the ECU 3O with a regular interrupt every predetermined time.

When the process moves to this routine, first step 201
At this time, the engine rotational speed NE is obtained based on the detected value of the rotational speed sensor 25, and the final intake flow rate GNEND determined according to the flowchart of FIG. 4 is also obtained. Then, in step 202, the fuel adhesion amount QMW on the wall surfaces of the intake manifolds 2a to 2d is calculated based on the captured engine speed NE and final intake flow rate GNEND. This fuel adhesion amount QMW is calculated for each injector 6A to 6.
Of the fuel injected from D, each intake manifold 2a to 2
This shows the amount of fuel remaining on the wall surface etc. of d. Further, as shown in FIG. 7, this fuel adhesion amount QMW is determined according to a predetermined three-dimensional map using the engine speed NE and final intake flow rate GNEND as parameters.

Next, in step 203, a rotation speed correction coefficient KNE is calculated from the captured engine rotation speed NE. This rotational speed correction coefficient KNE is determined according to a map as shown in FIG.

Then, in step 204, calculation is performed according to the following equation (4), and the calculation result is set as the attenuation term QTRN1 of the fuel adhesion correction amount in the current processing cycle.

QTRN 1←QTRNO* (1-KMI)+ (Q
MWI-QMWO) * (1-KM2) ... (4) Here, QTRNO is the attenuation term in the previous processing cycle, and QMWI is the fuel adhesion amount in the current processing cycle, QM
WO is the fuel adhesion amount in the previous treatment cycle, KMI, K
M2 is a constant serving as a fitness value.

Subsequently, in step 205, calculation is performed according to the following equation (5), and the calculation result is set as the fuel adhesion correction amount FMWI in the current processing cycle.

FMWI-[(QMWI-QMWO)*KM3+QTR
N1 *KM4] *KNE ... (5) 1, -1. - Te, QMWI, QMWO, and QTRNI are the same as those in step 204, KM3 is a constant as a matching value, and KNE is the rotational speed correction coefficient determined in step 203.

Next, in step 206, based on the detected value of the throttle opening sensor 21, a change in the throttle opening TA corresponding to a change in the load of the engine l is acquired. Then, in step 207, the throttle opening TAI in the current processing cycle and the throttle opening T in the previous processing cycle are determined.
The absolute value of the difference from AO is calculated, and the calculation result is set as the opening degree change ΔTA corresponding to the load change rate of the engine 1.

Then, in step 208, calculation is performed according to the following equation (6), and the calculation result is used as the fuel adhesion correction amount FMW.
Let the dead band of FMWFK be FMWFK.

FMWFK ←KFK* 1/ (ΔTA0m) −
(6) Here, KFK and m are constants each serving as a fitness value. In addition, the dead band FMWFK is the opening degree change Δ of the throttle valves 8A to 8D, as shown in FIG.
This corresponds to an area inside a curve that is defined in advance as a relationship between a fuel adhesion correction amount FMW that is inversely proportional to the magnitude of TA.

Next, in step 209, it is determined whether the absolute value of the fuel adhesion correction amount FMWI obtained in step 205 is smaller than the dead band FMWFK. It is determined whether the relationship between the fuel adhesion correction amount FMWI and the fuel adhesion correction amount FMWI is within the dead band FMWFK.

If the relationship between the fuel adhesion correction amount FMWI and the opening change ΔTA calculated this time is within the dead band FMWFK, the fuel adhesion correction amount FMWI is set to 10'' in step 210, and step 211
Move to. If the fuel adhesion correction amount FMWI for the opening degree change ΔTA calculated this time is not within the dead band FMWFK, the process directly proceeds to step 211.

In step 211 following step 209 or step 210, the cooling water temperature THW is acquired based on the detection signal of the water temperature sensor 24. And step 212
In the step, a water temperature correction coefficient KTHW is calculated based on the taken-in cooling water temperature THW. This water temperature correction coefficient KTHW is determined according to the map shown in FIG.

Further, in step 213, the fuel adhesion correction amount FM in the current processing cycle is added to the obtained water temperature correction coefficient KTHW.
WI is multiplied and the result is set as the final fuel adhesion correction amount FMW in the current processing cycle.

Finally, in step 214, the basic injection amount TP obtained in the flowchart of FIG.
The result is obtained as the final fuel injection amount TAU, and the subsequent processing is immediately terminated.

As mentioned above, in the fuel injection amount control device of this embodiment,
Assuming that the fuel supplied from each injector 6A to 6D adheres to the wall surface of each intake manifold 2a to 2d, the required fuel injection amount TAU is determined while correcting the amount of fuel adhering and the amount of evaporation. ing. Moreover,
As shown in FIG. 10, a dead band FMWFK is defined by predetermining the relationship between the fuel adhesion correction amount FMW that is inversely proportional to the magnitude of the opening change ΔTA of the throttle valves 8A to 8D corresponding to the load change rate of the engine 1. It is set up. and,
Based on the dead band FMWFK, it is determined whether or not to correct the basic injection amount TPO using the fuel adhesion correction amount FMW.

Therefore, during operation transients where the load change rate is large, that is, the opening degree change ΔTA is large, the dead band FMWFK becomes narrow as shown in FIG. 10, and even if the fuel adhesion correction amount FMW is minute, the correction amount F , MW determines the basic injection amount TP.
is corrected to determine the fuel injection amount TAU. In other words,
During transient operation when the throttle opening TA changes rapidly, the amount of fuel deposited on the intake manifolds 2a to 2d Q
Fuel injection amount control can be performed by reliably correcting the basic injection amount TP in consideration of MW.

On the other hand, during normal operation when the load change rate is small, that is, the opening change ΔTA is small, the dead band F
If the fuel adhesion correction amount FMW is small, the correction of the basic injection amount TP by the correction amount FMW is canceled.

In other words, during normal operation when the change in throttle opening TA is small, the amount of fuel deposited on the intake manifolds 2a to 2d is Q.
Fuel injection amount control is performed ignoring MW. That is, in the low-load operating range or low-speed operating range of the engine 1, if there are small load fluctuations or rotational speed fluctuations such as small fluctuations in the throttle opening TA, the basic injection amount TP is determined by the fuel adhesion correction amount FMW. Corrections are prohibited.

Therefore, the fuel adhesion correction amount FMW is no longer reflected in the fuel injection amount TAU, and during slow acceleration or steady state where the throttle opening degree TA changes only gradually, the fuel adhesion correction amount FMW
This prevents the fuel injection amount TAU from fluctuating.

As a result, acceleration surges and steady surges do not occur due to the fuel adhesion correction amount FMW, and deterioration of drivability can be prevented.

In addition, in the fuel injection amount control device of this embodiment, before the fuel adhesion correction amount FMWI is corrected by the water temperature correction coefficient KTHW, the fuel injection amount correction amount FMW reaches the dead band FMWFK.
It is determined whether or not it is within the range. Therefore, the determination as to whether or not to correct the basic injection amount TP using the fuel adhesion correction amount FMWI is not influenced by the cooling water temperature THW.

Therefore, it is possible to prevent the fuel injection amount TAU from fluctuating, especially when the cooling water temperature THW is low, and it is possible to prevent surges and obtain good drivability.

The present invention is not limited to the above-mentioned embodiments, and may be implemented as follows by appropriately changing a part of the structure without departing from the spirit of the invention.

(1) In the above embodiment, the movable vane type air flow meter 22 was used as the intake air amount equivalent value measuring means, but in addition to this, a hot wire type or Karman vortex type air flow meter may be used, or the intake pressure may be measured. An intake pressure sensor may also be used.

(2) In the above embodiment, the throttle opening sensor 2 detects the change in the throttle opening TA as a load change detection means.
1 is used, but it is also possible to use a rotation speed sensor 25 that detects changes in the engine rotation speed NE.

(3) In the above embodiment, in order to calculate the fuel adhesion amount QMW, the final intake flow rate GNEND is separately calculated based on the intake flow rate GA measured by the air flow meter 22.
However, the intake flow rate GA detected by the air flow meter 22 may be used directly.

(4) In the above embodiment, the engine 1 has four cylinders, but the engine may have a different number of cylinders.

(5) In the above embodiment, the independent throttle type engine 1
It can also be embodied in a conventional engine without an independent throttle.

[Effects of the Invention] As described in detail above, according to the present invention, the relationship between the calculated fuel adhesion correction amount and the load change rate is such that the relationship between the fuel adhesion correction amount that is inversely proportional to the magnitude of the load change rate is determined in advance. It is judged whether or not it is within a predetermined dead band, and if the judgment result is not within the dead band, the basic injection amount is allowed to be corrected by the fuel adhesion correction amount, and if the judgment result is within the dead band, Since correction of the basic injection amount using the fuel adhesion correction amount is prohibited, the amount of fuel adhesion in the intake system can be reliably corrected during transient operation with a large rate of load change, and during steady-state conditions with a small rate of load change. etc., it has the excellent effect of canceling the correction of the amount of fuel adhering to the intake system and preventing surges.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic configuration of this invention, Figures 2 to 1
Fig. 0 is a diagram of an embodiment embodying the present invention, Fig. 2 is a schematic configuration diagram of a gasoline engine system to which a fuel injection amount control device for an internal combustion engine is applied, and Fig. 3 is an electrical configuration thereof. FIG. 4 is a flowchart illustrating the calculation process of the basic injection amount executed by the fuel injection amount control device, FIG. 5 is a time chart illustrating the calculation of the final intake flow rate during transient operation, Fig. 6 is a flowchart explaining the fuel injection amount control executed by the fuel injection amount control device, and Fig. 7 is a flowchart illustrating the fuel injection amount control performed by the fuel injection amount control device, and Fig. 7 shows the flowchart 3 in which the engine rotation speed and final intake flow rate are used as parameters to determine the fuel adhesion amount.
Dimensional map. Figure 8 is a map showing the rotational speed correction coefficient for the engine rotational speed. Figure 9 is a map showing the water temperature correction coefficient for the cooling water temperature. Figure 10 is a map showing the difference between the throttle opening degree change and the fuel adhesion correction amount. It is a figure explaining the dead zone in a relationship. In the figure, Ml is the internal combustion engine, M2 is the intake system, M3 is the fuel injection means, M4 is the intake air amount equivalent value measuring means, M5 is the engine rotation speed detecting means, M6 is the adhesion amount calculation means, and Ml is the adhesion correction amount calculation means. , M8 is an injection amount calculation means, M9 is a load change detection means, MIO is a load change rate calculation means, Mll is a dead band judgment means, Ml2 is a correction control means, 1 is an engine as an internal combustion engine, and 2 is an intake system. Intake passage, 6A to 6D
21 is an injector as a fuel injection means, 21 is a throttle opening sensor as a load change detection means, 22 is an air flow meter as an intake air amount equivalent value measuring means, 25 is a rotation speed sensor as an engine rotation speed detection means, and 30 is an attachment. The ECU constitutes an amount calculation means, an adhesion correction amount calculation means, an injection amount calculation means, a load change rate calculation means, a dead band judgment means, and a correction control means. Patent applicant Toyota Motor Corporation Nippondenso Co., Ltd. Agent Patent attorney On 1) Hironobu (and 1 other person) O Q THW ('C) △TA QM prisoner E 00O E (rpm)

Claims (1)

[Scope of Claims] 1. A fuel injection means for injecting fuel into an intake system of an internal combustion engine; an intake air amount equivalent value measuring means for measuring an intake air amount equivalent value in the intake system; and a rotation speed of the internal combustion engine. an engine rotational speed detection means; an adhesion amount calculation means for sequentially calculating the amount of fuel adhering to the intake system in a steady state based on the measured intake air amount equivalent value and the detected internal combustion engine rotational speed; Adhesion correction amount calculation means for calculating a fuel adhesion correction amount based on the difference between the calculated fuel adhesion amount and the previously calculated fuel adhesion amount; and correcting the basic injection amount using the calculated fuel adhesion correction amount. In the fuel injection amount control device for an internal combustion engine, the fuel injection amount control device includes: injection amount calculation means for calculating a required amount of fuel to be injected from the fuel injection means; load change detection means for detecting a load change of the internal combustion engine; load change rate calculation means for calculating the load change rate at each time based on the detected load change; and a relationship between the calculated fuel adhesion correction amount and the calculated load change rate;
dead band determining means for determining whether the relationship between the fuel adhesion correction amount, which is inversely proportional to the magnitude of the load change rate, is within a predetermined dead band; and if the determination result is not within the dead band; If the basic injection amount is allowed to be corrected by the fuel adhesion correction amount in the injection amount calculation means, and the judgment result is within the dead band, the basic injection is performed by the fuel adhesion correction amount in the injection amount calculation means. 1. A fuel injection amount control device for an internal combustion engine, comprising: correction control means for prohibiting correction of the amount.