JPH05180036A - Fuel-injection control apparatus of internal-combustion engine - Google Patents

Abstract

PURPOSE:To obtain the fuel injection control apparatus of an internal-combustion engine, which can properly learn fuel correction value at acceleration- deceleration running. CONSTITUTION:A fuel injection valve 6 is provided in an intake manifold 5 and an O2 sensor 13 is provided on an exhaust pipe 3. Opening of a throttle valve 9 is detected by a throttle position sensor 10. Correction coefficient during acceleration running is memorized in RAM of ECU 15. MPU of ECU 15 computes basic fuel injection quantity based on intake air pressure detected by an intake pipe pressure sensor 4 and a fuel injection quantity is corrected, in relation to the basic fuel injection quantity by using correction coefficient during acceleration running. The MPU of the ECU 15 determines whether renewal of the correction coefficient is allowed or not, based on the difference in rich.lean time in the O2 sensor 13 at the time when time changing rate, about opening of the throttle valve 9 by the throttle position sensor 10, is in two different conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine, and more particularly to a fuel injection control device for performing learning control of a correction coefficient during acceleration / deceleration.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection control device for an internal combustion engine, a basic fuel injection amount is calculated based on an intake air amount or an intake air pressure, and the basic fuel injection amount is corrected by acceleration / deceleration operation or the like. The injection amount is calculated. further,
The correction coefficient at the time of this acceleration / deceleration operation is learned. In other words, due to variations in each internal combustion engine, changes over time, and the like, for example, even if the acceleration is the same, the amount of fuel increase required for each engine is different. Therefore, by learning this fuel increase, it is always attempted to supply the optimum fuel injection amount. To do.
Then, as the change amount of the engine parameter, the change amount of the intake pressure (ΔPm) or the change amount of the intake air amount per engine rotation (ΔQ / N) is used, and when the change amount exceeds a predetermined value, the acceleration increase amount is increased. A correction value calculation trigger is applied, and the correction coefficient for acceleration / deceleration operation is learned from the rich / lean time ratio of the O ₂ sensor signal for a fixed period thereafter.

[0003]

However, since the trigger condition for calculating the correction value is fixed, more specifically, the correction coefficient is learned when it is determined that the variation ΔPm of the intake pressure is a predetermined value or more. However, there has been a problem that the correction coefficient is not properly learned depending on the difference in acceleration state. That is, there is a problem that the correction coefficient is excessively learned in a place where it is not necessary to learn it.

Therefore, an object of the present invention is to provide a fuel injection control device for an internal combustion engine, which can appropriately learn a fuel correction value during acceleration / deceleration operation.

[0005]

According to the present invention, as shown in FIG. 10, a fuel injection valve M1 for injecting fuel into an internal combustion engine.
An air-fuel ratio detecting means M2 for detecting an air-fuel ratio of the air-fuel mixture to the internal combustion engine, a throttle valve opening detecting means M3 for detecting an opening of a throttle valve provided in an intake pipe of the internal combustion engine, and an intake air amount. Alternatively, intake air detection means M4 for detecting intake air pressure, and basic fuel injection amount calculation means M for calculating the basic fuel injection amount by the fuel injection valve M1 based on the intake air amount or intake air pressure by the intake air detection means M4.
5, an acceleration / deceleration correction coefficient storage means M6 that stores a correction coefficient during acceleration or deceleration operation, and the acceleration / deceleration correction coefficient storage means M6 for the basic fuel injection amount by the basic fuel injection amount calculation means M5. A fuel injection amount correction means M7 for correcting the fuel injection amount using the stored correction coefficient at the time of acceleration or deceleration operation, and a time change amount of the throttle valve opening degree by the throttle valve opening degree detection means M3 of two or more. Correction coefficient update determination means M for determining whether or not the update of the correction coefficient of the acceleration / deceleration correction coefficient storage means M6 is permitted based on the air-fuel ratio by the air-fuel ratio detection means M2 in different states.
8 is a fuel injection control device for an internal combustion engine including the above.

[0006]

The fuel injection amount correcting means M7 uses the correction coefficient at the time of acceleration or deceleration operation stored in the acceleration / deceleration correction coefficient storage means M6 for the basic fuel injection amount by the basic fuel injection amount calculation means M5. Correct the amount. Further, the correction coefficient update determination means M8 uses the air-fuel ratio detected by the air-fuel ratio detection means M2 when the time variation of the throttle valve opening detected by the throttle valve opening detection means M3 is two or more different states. It is determined whether updating of the correction coefficient of the correction coefficient storage unit M6 is permitted. That is, it is determined whether or not the correction coefficient is updated according to a state in which the time change amount of the opening of the throttle valve is two or more different, that is, a difference in acceleration / deceleration state.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an internal combustion engine and its control system. An intake pipe 2 and an exhaust pipe 3 are connected to the internal combustion engine body 1. An intake pipe pressure sensor 4 is attached to the intake pipe 2, and the intake air pressure is detected by the sensor 4. A semiconductor pressure sensor is used as the intake pipe pressure sensor 4.

An electromagnetically operated fuel injection valve 6 is provided in the intake pipe 2 near each cylinder intake port of the intake manifold 5. Also, distributor 7
The rotor is rotationally driven at a rotation speed of 1/2 of the engine rotation. A rotation sensor 8 is provided inside the distributor 7, and the sensor 8 outputs a signal indicating the engine speed / fuel injection timing and a cylinder discrimination signal.

A throttle valve 9 is provided in the intake pipe 2, and the opening of the throttle valve 9 is detected by a throttle position sensor 10. Further, the cooling water temperature of the internal combustion engine is detected by the water temperature sensor 11. A thermistor type is used for the water temperature sensor 11. Further, an intake air temperature sensor 12 is provided in the intake pipe 2, and the intake air temperature is detected by the sensor 12.

An O ₂ sensor 13 is attached to the exhaust pipe 3, and this sensor 13 detects whether the air-fuel ratio is rich or lean with respect to the stoichiometric air-fuel ratio. In the figure, 14 is an air amount control valve (solenoid valve) for idle rotation control.

FIG. 2 shows an electrical configuration. That is, the figure shows an electronic control unit (hereinafter referred to as ECU) 15 that controls the fuel injection amount of the internal combustion engine to control the air-fuel ratio.
A block diagram of various sensors and the like is shown, and the ECU 15 is mainly composed of a microcomputer.

The ECU 15 takes in each detection signal from the intake pipe pressure sensor 4, the rotation sensor 8, the throttle position sensor 10, the water temperature sensor 11, the intake air temperature sensor 12, and the O ₂ sensor 13, and based on these detection data, the fuel is detected. The injection amount is calculated, the valve opening time of the fuel injection valve 6 is controlled, and the air-fuel ratio control is performed.

The ECU 15 includes an MPU (microprocessor unit) 16, an interrupt control section 17, and a counter section 18.
And interface section 19, A / D conversion section 20 and ROM
21, a RAM 22, an output port 23, a fuel injection time control counter unit 24, and a power amplifier 25. The MPU 16 executes arithmetic processing according to a predetermined program. The interrupt controller 17 outputs an interrupt signal to the MPU 16. The counter unit 18 counts the rotation angle signal from the rotation sensor 8 and calculates the engine rotation speed. The A / D converter 20 selectively inputs detection signals (analog signals) from the intake pipe pressure sensor 4, the water temperature sensor 11, the intake temperature sensor 12, and the throttle position sensor 10 and converts them into digital signals. The signal from the intake pipe pressure sensor 4 is A / D converted every predetermined period (for example, 16 msec), and the A / D converted value is stored in the RAM 22.

The ROM 21 is a read-only memory in which programs and map data used for calculation are stored in advance. The RAM 22 is a writable and readable nonvolatile memory, and retains the stored contents even after the key switch is turned off. The RAM 22 stores a correction coefficient for acceleration operation (acceleration correction coefficient FDPC) described later.

The output port 23 is connected to the air amount control valve 14 (electromagnetic valve). The fuel injection time control counter unit 24 is an output counter unit for outputting a fuel injection amount (time) control signal including a register, receives the fuel injection amount data sent from the MPU 16, and based on this data, the fuel injection valve. The duty ratio of the control pulse signal for controlling the valve opening time of No. 6 is determined, and the injection amount control signal is output.
The output fuel injection time control counter unit 24
A control signal output from the fuel injection valve 6 for each cylinder is applied via the power amplifier 25.

In the ECU 15, the MPU 16,
Interrupt controller 17, counter 18, A / D converter 2
0, the ROM 21, the RAM 22, the output port 23, the interface unit 19, and the counter unit 24 are each connected to the common bus 26, and necessary data is transferred by the MPU.
16 commands.

In this embodiment, the intake pipe pressure sensor 4 serves as the intake air detection means, the throttle position sensor 10 serves as the throttle valve opening detection means, the O ₂ sensor 13 serves as the air-fuel ratio detection means, and the MPU 16 serves as the MPU 16. The basic fuel injection amount calculation means, the fuel injection amount correction means, the correction coefficient update determination means, and the RAM 22 constitute acceleration / deceleration correction coefficient storage means.

Next, the operation of the fuel injection control device for the internal combustion engine thus configured will be described. FIG. 3 shows a main routine executed by the MPU 16. First, the MPU 16 calculates the engine speed NE in step 100, and calculates the intake pipe pressure Pm in step 200. And MPU1
In step 300, the basic fuel injection time Tp is calculated from the engine speed NE and the intake pipe pressure Pm in step 300.
Various increase factors are calculated from 00 to 700. That is, in step 400, the water temperature increase coefficient FWL is set to step 500.
At step 600, the high load increase coefficient FOTP at step 600, and the acceleration increase coefficient F at step 700.
Calculate AEW.

Thereafter, in step 800, the MPU 16 corrects the basic fuel injection time Tp by various increasing factors according to the following equation and final fuel injection time (final injection pulse) TAVE.
To calculate.

[0020]

[Equation 1] TAVE = Tp · FWL · (FASE + FOT
P + FAEW) FIGS. 4, 5, 6 and 7 show details of the calculation processing of the acceleration increase coefficient FAEW in step 700. Further, FIG. 8 is a time chart for explaining these processes.

In FIG. 8, two acceleration operations are performed. That is, the throttle valve 9 is operated to open at the timings of t1 and t3, and the time change amount ΔTA of the throttle opening TA is small at the timing of t1 (gradual acceleration) and is large at the timing of t3 ( Sudden acceleration). Further, in the time change amount ΔTA of the opening degree TA of the throttle valve 9, the first determination value DELT
A1 and the second determination value DELTA2 (> DELTA1) are set. The unit of the time change amount ΔTA of the throttle opening TA is, for example, ° / ms. The first determination value DELTA1 is set to, for example, 0.8 ° / 8 ms, and the second determination value DELTA2 is set to, for example,
It is set to 1.6 ° / 8 ms.

FIGS. 4 and 5 are flowcharts showing the processing operation for determining whether or not it is the timing to update (learn) the acceleration correction coefficient FDPC for correcting the acceleration increase coefficient FAEW. In FIG. 4, in step 701, the update permission flags FACC1 and FACC2 are reset (= 0). Then, in step 702, the MPU 16 determines whether or not the time variation amount ΔTA of the throttle opening is equal to or greater than the first determination value DELTA1, and ΔTA <DELTATA
If it is 1, the process proceeds to step 707 and it is determined whether or not the update permission flag FACC1 is set (= 1). If the MPU 16 is not set, the update permission flag FACC2 is set (=) in step 711 of FIG.
1) If it is not set by judging whether it has been done,
The counter CACC is incremented by "1". It should be noted that this counter CACC holds its value at full scale and does not overflow.

Thereafter, the MPU 16 judges in step 716 whether or not the update permission flag FACC1 is set (= 1), and if not set, step 717.
If it is determined that the update permission flag FACC2 is not set (= 1), the process returns to step 702 of FIG.

At the timing before t1 in FIG.
Step 701 → 702 → 707 → 711 → 715 → 7
Repeat 16 → 717 → 702. And MPU16
When the time change amount ΔTA of the throttle opening becomes equal to or larger than the first determination value DELTA1 in step 702 (timing t1 in FIG. 8), the process proceeds to step 703. MP
The U16 sets the value of the counter CACC to “0” in step 703, and then in step 704, the time change amount ΔTA of the throttle opening is set to the second determination value DELTA2 (> DELT).
It is determined whether or not A1) or more, and if ΔTA <DELTA2, the process proceeds to step 706 and the update permission flag FAC.
Set (= 1) C2. Then, step 707 →
The process moves to 711.

Since FACC2 = 1 in step 711, it is determined in step 712 whether the value of the counter CACC is smaller than the second count determination value T2. Since the value of the counter CACC is initially smaller than the determination value T2, the value obtained by adding the predetermined value α to the value of the counter CDPC2 is set as the new value of the counter CDPC2 in step 713. Here, α takes a positive value when the O ₂ sensor 13 is on the lean side, and takes a negative value when the O ₂ sensor 13 is on the rich side.

After that, steps 715 → 716 → 717
→ Transition to 712. At the timing of t1 to t2 in FIG. 8, steps 712 → 713 → 715 → 716 → 71
Repeat 7 → 712.

Then, in step 712, the counter CAC
When the value of C reaches the second count determination value T2 (t2 in FIG. 8).
Timing), in step 712, the update permission flag F
Reset ACC2 (= 0), step 715 → 71
6 → 717 → 702, and steps 707 → 711
→ 715 → 716 → 717 → 702 → 707 are repeated.

After that, in step 702, the time change amount ΔTA of the throttle opening is set to the first judgment value DELTA1.
As described above, the counter CACC is set to "0" in step 703, and when the time change amount ΔTA of the throttle opening becomes equal to or larger than the second determination value DELTA2 in step 704 (timing of t3 in FIG. 8), the process proceeds to step 705.
In step 705, the MPU 16 updates the update flag FAC.
C1 is set (= 1). After that, the routine proceeds to Step 707, and since FACC1 = 1, it is judged at Step 708 whether the value of the counter CACC is smaller than the first count judgment value T1. Since the value of the counter CACC is initially smaller than the determination value T1, the value obtained by adding the predetermined value β to the value of the counter CDPC1 is set as the new value of the counter CDPC1 in step 709. Where β is the O ₂ sensor 13
Takes a positive value if is lean, and takes a negative value if is rich. The judgment value (judgment time) T1 is, for example, 2 s.
is set to ec and the determination value (determination time) T
2 is set to 1 sec, for example.

Then, steps 711 → 715 → 716
→ Go to 707. At the timing of t3 to t6 in FIG. 8, steps 707 → 708 → 709 → 711 →
715 → 716 → 707 is repeated. During this process, the O ₂ sensor 13 becomes lean at t3 to t4 and t5 to t6 in FIG.
The value of 1 is added by β, and from t4 to t5 in FIG.
The O ₂ sensor 13 becomes rich, and in step 709, the value of the counter CDPC1 is subtracted by β.

Then, in step 708, the counter CAC
When the value of C becomes larger than the first count determination value T1 (timing of t6 in FIG. 8), the update permission flag FACC1 is reset (= 0) in step 710, and step 71
The process shifts to 1 → 715 → 716 → 717 → 702.

During the process of FIGS. 4 and 5, FIG.
The scheduled interrupt processing of is executed. Note that FIG. 6 is a routine for determining whether or not to update the acceleration correction coefficient FDPC based on the values of the counters CDPC1 and CDPC2, and actually performing the update operation of the acceleration correction coefficient FDPC.

In FIG. 6, after it is confirmed in step 720 that the count values of the counters CDPC1 and CDPC2 are not "0", the counter CDPC is counted in step 721.
1 and CDPC2 count value difference (= CDPC1-C
DPC2) is larger than a predetermined value C, and if it is larger, the acceleration correction coefficient FDPC is set to a predetermined value γ in step 724.
Is added (timing of t7 in FIG. 8). Then, in step 725, the counters CDPC1 and CDPC2 are both set to "0". On the other hand, in step 721, the counter CD
Difference in count value between PC1 and CDPC2 (= CDPC1
If CDPC2) is smaller than the predetermined value C, step 722
Then, the difference between the count values of CDPC1 and CDPC2 (= CD
PC1−CDPC2) is smaller than a predetermined value −C, and if smaller, in step 723, the acceleration correction coefficient FDP is calculated.
The predetermined value γ is subtracted from C and the process proceeds to step 725.
In step 722, the difference between the count values of CDPC1 and CDPC2 is larger than the predetermined value -C, that is, -C <(C
If DPC1-CDPC2) <+ C, step 72
The updating process of the FDPC 3724 is not performed.

That is, the counters CDPC1 and CDPC2
The fact that the absolute value of the difference in the count values (= CDPC1-CDPC2) is large means that the time during which the air-fuel ratio is disturbed due to sudden acceleration (the time during which it is rich or lean) is long. Therefore, transient air-fuel ratio correction is necessary, and the acceleration correction coefficient FDPC is updated.

The reason for learning the acceleration increase factor FAEW will be explained in more detail. The air-fuel ratio becomes lean because the intake air amount increases during acceleration. Therefore, if a change in the intake air amount is detected and the fuel injection amount is increased by a predetermined amount according to the change, ideally, the air-fuel ratio will not be disturbed, and it will always be possible to control the air-fuel ratio to be close to the theoretical air-fuel ratio. it can. However, due to the fact that deposits actually adhere to the intake valve, variations between internal combustion engines, and differences in fuel volatility, even if the intake air amount is increased by a predetermined amount in this way, The air-fuel ratio eventually becomes lean because not all of the increased amount is supplied to the cylinder due to adhesion to the surface of the pipe or intake valve. Therefore, by learning the degree of increase in the fuel injection amount, it is possible to prevent the air-fuel ratio from being controlled to the lean side for the reasons described above.

Further, the scheduled interrupt process of FIG. 7 is executed in the middle of the processes of FIGS. Step 7
In step 30, it is determined whether or not the time change amount ΔTA of the throttle opening is larger than a predetermined value A. If it is larger, in step 731, the basic acceleration increase coefficient FAEWB is corrected by the acceleration correction coefficient FDPC by the following equation to obtain the final acceleration increase coefficient. FAEW
To calculate.

[0036]

## EQU2 ## FAEW = FAEWB (1 + FDPC) Here, the basic acceleration increase coefficient FAEWB is calculated using a map having the water temperature shown in FIG. 9 as an element.

Then, the final acceleration increase coefficient FAEW
Are used in the process of step 800 in FIG. As described above, in the present embodiment, the difference between the rich and lean times of the O ₂ sensor 13 when the temporal change amount (ΔTA) of the opening degree of the throttle valve 9 is in two different states (gradual acceleration and rapid acceleration). As a result, it is determined in steps 721 and 722 of FIG. 6 whether or not updating of the acceleration correction coefficient FDPC is permitted, so that the learning value (acceleration correction coefficient FDPC) can be updated appropriately.

The present invention is not limited to the above embodiment, and for example, the correction coefficient during acceleration operation has been described in the above embodiment, but it may be embodied in updating the correction coefficient during deceleration operation. .. That is, the correction coefficient at the time of deceleration operation may be updated with deceleration when the time variation ΔTA of the throttle opening is negative.

Further, as the O ₂ sensor 13 as the air-fuel ratio detecting means, an air-fuel ratio sensor which linearly detects the air-fuel ratio may be used. Further, the intake pipe pressure sensor 4 as the intake air detecting means may use an air flow meter for detecting the intake air amount, and the basic fuel injection amount is calculated using the intake air amount. Good.

Further, the memory (RAM 22) storing the correction coefficient during acceleration / deceleration operation may be a backup memory in addition to the non-volatile memory. Also, throttle valve 9
The time change amount ΔTA of the opening degree is not limited to two states, and it may be determined whether or not the update of the correction coefficient is permitted based on the air-fuel ratio in two or more different states.

[0041]

As described in detail above, according to the present invention,
The excellent effect that the fuel correction value at the time of acceleration / deceleration operation can be properly learned is exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a fuel injection control device for an internal combustion engine of an embodiment.

FIG. 2 is a diagram showing an electrical configuration of a fuel injection control device for an internal combustion engine.

FIG. 3 is a diagram showing a flowchart for explaining an operation.

FIG. 4 is a diagram showing a flowchart for explaining the operation.

FIG. 5 is a diagram showing a flowchart for explaining the operation.

FIG. 6 is a diagram showing a flowchart for explaining the operation.

FIG. 7 is a diagram showing a flowchart for explaining the operation.

FIG. 8 is a diagram showing a time chart for explaining the operation.

FIG. 9 is a diagram showing a map for determining a basic acceleration amount increase coefficient.

FIG. 10 is a claim correspondence diagram.

[Explanation of symbols]

2 intake pipe 4 intake pipe pressure sensor as intake air detection means 6 fuel injection valve 9 throttle valve 10 throttle position sensor as throttle valve opening detection means 13 O ₂ sensor as air-fuel ratio detection means 16 basic fuel injection amount calculation means , Fuel injection amount correction means,
MPU 22 as correction coefficient update determination means RAM as acceleration / deceleration correction coefficient storage means

Claims (1)

[Claims] 1. A fuel injection valve for injecting fuel into an internal combustion engine, an air-fuel ratio detecting means for detecting an air-fuel ratio of an air-fuel mixture to the internal combustion engine, and an opening of a throttle valve provided in an intake pipe of the internal combustion engine. Throttle valve opening detecting means for detecting, intake air detecting means for detecting intake air amount or intake air pressure, and basic fuel injection amount by the fuel injection valve based on intake air amount or intake air pressure by the intake air detecting means A basic fuel injection amount calculation means, an acceleration / deceleration correction coefficient storage means that stores a correction coefficient during acceleration or deceleration operation, and the acceleration / deceleration correction coefficient for the basic fuel injection amount calculated by the basic fuel injection amount calculation means. Fuel injection amount correction means for correcting the fuel injection amount using the correction coefficient for acceleration or deceleration operation stored in the storage means, and the slot by the throttle valve opening detection means. Correction for determining whether or not to permit updating of the correction coefficient of the acceleration / deceleration correction coefficient storage means based on the air-fuel ratio by the air-fuel ratio detection means when the amount of change over time of the valve opening is two or more different states A fuel injection control device for an internal combustion engine, comprising: a coefficient update determination means.