JPH0536618B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply control device for an internal combustion engine.
In particular, it relates to acceleration increase correction of the fuel supply amount during acceleration.

[Prior Art] Conventionally, the amount of fuel injection required during acceleration of an internal combustion engine is required to be greater than the amount of fuel injection during steady state.
In order to correct the difference between the required fuel injection amount and the fuel injection amount, when the opening speed of the throttle opening is greater than a predetermined value, the device determines that it is an acceleration state and increases the fuel injection amount according to the opening. has been proposed (for example, Japanese Patent Laid-Open No. 150045/1983).

[Object of the Invention] However, although changes in the intake air amount to the internal combustion engine immediately follow changes in the throttle opening, the means for detecting the intake air amount, such as an air flow meter or an intake pipe pressure sensor, are As shown in FIG. 1, with respect to the change in the intake air amount indicated by the solid line V in the figure, a response delay as shown by the broken line S in the figure exists immediately after the start of the change in the intake air amount. Therefore, in a device that increases the fuel injection amount according to the opening speed of the throttle opening as described above, when the throttle valve opens to a certain extent from the start of acceleration and the response delay of the intake air amount becomes small, the amount of fuel injection is increased by the increase correction. There is a problem in that the air-fuel ratio becomes overrich and exhaust emissions deteriorate.

The present invention has been made in view of the above-mentioned problems, and its purpose is to easily determine an appropriate fuel injection amount during acceleration according to the throttle opening degree and opening speed from the start of acceleration. It is an object of the present invention to provide a device capable of preventing deterioration of exhaust emissions by correcting the increase in quantity through control.

[Means for Solving the Problems] As illustrated in FIG. 2, the present invention includes a throttle opening detection means for detecting the throttle opening of a throttle valve that adjusts the amount of air taken into an internal combustion engine; opening speed detection means for detecting the opening speed of the throttle opening; acceleration opening detection means for detecting the start of acceleration of the internal combustion engine; and when the start of acceleration is detected by the acceleration start detection means, the opening speed of the throttle opening is maximum throttle opening setting means for setting a maximum throttle opening according to the opening speed; and when the opening speed is at least a predetermined value and the throttle opening is below the maximum throttle opening, the fuel supply amount is set at the maximum throttle opening according to the opening speed; and a fuel supply means that increases the amount of fuel according to the opening speed, and does not increase the amount of fuel supplied when the opening speed is less than a predetermined value or the throttle opening is larger than the maximum throttle opening. The gist is engine fuel supply control means.

[Operation] With the above configuration, when the start of acceleration is detected by the acceleration start detection means, the maximum throttle opening setting means sets the maximum throttle opening according to the throttle opening and the opening speed. Then, in an acceleration state where the opening speed is higher than a predetermined value and the throttle opening is less than the maximum throttle opening, the fuel supply means increases the fuel supply amount according to the opening speed. When the opening degree is larger than the maximum throttle opening degree, the fuel supply amount is not increased.

As a result, the amount of fuel is effectively increased during the first half of acceleration (lower than the throttle opening setting), and no increase is made during the second half. Furthermore, control can be easily achieved since it is compared with a set value.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 3 is a schematic configuration diagram of an internal combustion engine and its peripheral devices in an embodiment of the present invention, and FIG. 4 is a control system diagram centered on an electronic control circuit incorporating a microcomputer as addition fuel supply control means.

In the figure, 1 is a six-cylinder engine, 2 is an air pipe pressure sensor that detects the internal pressure of the intake manifold 3 to determine the amount of intake air, and 4 is the engine 1.
The fuel injection valve 4 is an electromagnetic fuel injection valve provided near each cylinder intake port of the intake manifold 3, and fuel whose pressure is adjusted to a constant level is fed under pressure to the fuel injection valve 4 from a fuel pump (not shown). Actually, there are six fuel injection valves 4a and 4, corresponding to the number of cylinders.
b, 4c, 4d, 4e, and 4f exist, but these are represented here and will be treated as the fuel injection valve 4 in the following explanation. 5 is an ignition coil forming a part of the engine ignition system, and 6 is a distributor that distributes ignition energy from the ignition coil 5 to spark plugs 7 provided in each cylinder. As is well known, the distributor 6 is located on the engine crankshaft 2.
It rotates once per rotation, and is provided with a rotation angle sensor 8 for detecting the engine rotation angle inside. 9 is the throttle valve of engine 1, 1
0 is a throttle sensor that detects the opening degree of the throttle valve 9, 11 is a cooling water temperature sensor that detects the warm-up state of the engine 1, 12 is an intake air temperature sensor that detects the intake air temperature, and 13 is an exhaust manifold 14. It is an air-fuel ratio sensor that detects the air-fuel ratio from the oxygen concentration in the exhaust gas, and the voltage is about 1 volt when the air-fuel ratio is smaller than the stoichiometric air-fuel ratio, that is, rich, and 0.1 volt when it is larger than the stoichiometric air-fuel ratio, that is, lean. Outputs a voltage of about volts.

20 is an electronic control circuit that controls the normal fuel injection amount to the engine 1 and also works as an additional fuel supply control means, which includes an intake pipe pressure sensor 2, a rotation angle sensor 8, a throttle sensor 10, and a cooling water temperature sensor. 11. The fuel injection amount is calculated based on the detection signals of the intake air temperature sensor 12 and the air-fuel ratio sensor 13, and the opening time of the fuel injection valve 4 is adjusted.

Next, we will discuss the internal configuration of the electronic control circuit 20 in the fourth section.
This will be explained using figures. 100 is a central processing unit (CPU) that calculates the fuel injection amount; 101 is an interrupt command unit; 102
103 is a rotation speed counter unit that calculates the engine rotation speed by counting the period of a predetermined rotation angle in response to a clock signal of a predetermined frequency from the CPU 100; 103 receives a detection signal from the air-fuel ratio sensor 13 and transfers it to the CPU 100; A digital input port 104 converts the detection signals from the intake pipe pressure sensor 2 and the throttle opening sensor 10 into A/D.
This is an A/D conversion processing unit that has the function of causing the CPU 100 to read data. Each of these units 10
The output information of 2, 103, 104 is common bus 10
5 to the CPU 100. 106 is
A memory unit in which a control program for the CPU 100 is stored and output information from each unit 101, 102, 103, and 104 is temporarily stored.
Information transfer to and from 100 is also performed via common bus 105. 107 is a counter unit for controlling the ignition timing including a register, and the CPU 10
A digital signal representing the timing to energize the ignition coil 5 and the timing to cut off the energization, that is, the ignition timing, calculated based on 0, is calculated as the timing and timing corresponding to the engine rotation angle (crank angle).
A power amplifier 108 amplifies the output of the ignition timing control counter unit 107 to energize the ignition coil 5 and to control the timing at which the ignition coil 5 is de-energized, that is, the ignition timing.

Reference numeral 109 is a fuel injection timing control counter unit including a register, and is composed of two down counters having the same function. In this case, each down counter converts a digital signal representing the opening time of the fuel injection valve 4 calculated by the CPU 100, that is, the fuel injection amount, into a pulse signal having a time width giving the opening time of the fuel injection valve 4. A power amplifier 110 amplifies the pulse signal from the counter unit 109 and supplies it to the fuel injection valve 4, and is provided with two channels corresponding to the configuration of the counter unit 109.

As shown in FIG. 4, the rotation angle sensor 8 consists of three sensors 181, 182, and 183. That is,
The first rotation angle sensor 181 rotates every two rotations of the engine crankshaft, that is, one rotation of the distributor 6, as shown as A in the time chart of FIG.
The angle signal A is generated only once per rotation at a position an angle θ before the crank angle 0. Second
As shown as B in FIG. 5, the rotation angle sensor 182 generates an angle signal B only once every two revolutions of the engine crankshaft at a position a predetermined angle θ from the crank angle of 360°. The third rotation angle sensor 183, as shown as C in FIG.
In the case of cylinders, there are 6 cylinders for each 60° crank angle from 0°.
An angle signal C is generated.

The interrupt command unit 101 is connected to each rotation angle sensor 1.
The angle signal, that is, the crankshaft rotation signal from 81, 182, 183 is inputted to send out a signal instructing interruption of ignition timing calculation and fuel injection calculation. D in the figure
As shown, a signal obtained by frequency-dividing the angle signal C of the third rotation angle sensor 183 by two is sent as an interrupt command signal D immediately after the angle signal A of the first rotation angle sensor 181 is sent. . This interrupt command signal D is sent six times per two revolutions of the crankshaft, that is, the number of cylinders in the engine is transmitted every two revolutions of the crankshaft. Therefore, in the case of 6 cylinders, the crank angle
It is sent once every 120 degrees and issues an interrupt command to the CPU 100 to calculate the ignition timing. Furthermore, as shown as E in FIG. Signal A and second rotation angle sensor 1
This interrupt command signal E is sent as an interrupt command signal E every 360 degrees (one revolution) starting at the sixth angle signal B after the angle signal B of 82 is sent out, that is, at a crank angle of 300 degrees. Interrupts the calculation. In response to this interrupt command, the CPU 100 calculates a normal fuel injection amount that is performed in synchronization with the rotation of the engine 1.

The fuel supply control performed in the engine 1 and its peripheral devices configured as described above will be described below.

The fuel injection control in this embodiment is activated every 20 msec, and the control routine shown in FIG.
FLAGX is initialized to 0 immediately after the electronic control circuit 20 is powered on. First step
At 200, the latest throttle opening TAi from the throttle sensor 10 is retrieved from a predetermined area for temporary storage in the memory unit 106 as the throttle opening TAi _-1 when this control routine was last processed.
The process of reading each of them is performed. In the following step 210, in preparation for the next processing of this control routine, the previous value TAi _-1 is updated with the throttle opening TAi read in step 200, that is, the throttle opening TAi is stored in memory as TAi _-1 . A process of storing the data in a predetermined area of the unit 106 is performed. In the following step 220, the step
A process is performed in which the difference between the throttle opening TAi read in step 200 and TAi _-1 is calculated as ΔTA.
This control routine is started every 20msec, so
ΔTA corresponds to the amount of change in the opening degree of the throttle valve 9 during this period, that is, the opening speed. next step
230, the opening speed of throttle valve 9 △TA
A determination is made as to whether or not TAso is greater than or equal to a predetermined value TAso. As shown in FIG. 7, the predetermined value TAso is such that the asynchronous injection of fuel performed based on the state (opening degree and opening speed) of the throttle valve 9 is such that below that value, there is no need to perform the asynchronous injection. It is given as the opening speed of the throttle valve 9. In other words, during acceleration when the increase in the amount of intake air does not cause the air-fuel ratio to become overly lean, in other words, during acceleration where the dilution of the air-fuel mixture is not a problem, it is necessary to control the increase in the amount of fuel at the beginning of acceleration using asynchronous injection. It will be determined that there is no such thing. Judgment at step 230 is “NO”
As mentioned above, when fuel increase control by asynchronous injection is not required, the process is performed in steps.
Proceed to 240, set the flag FLAGX = 0, and then
The control routine ends. step
If the determination at step 230 is "YES", that is, △TA≧TAso, the process proceeds to step 250, where a flag indicating execution of fuel increase control by asynchronous injection is set.
Check the value of FLAGX. If FLAGX=0, it is determined that asynchronous injection was not performed in the previous control routine process, and the process proceeds to step 260.
If FLAGX=1, it is assumed that asynchronous injection has already been performed and the process moves to step 270.

First, the processing from step 260 onwards will be explained. In step 260, the throttle opening degree TA from the start of acceleration corresponding to the current throttle opening speed ΔTA is calculated from the map shown in FIG. Setting value
A process is performed in which TAAao is read and multiplied by constants K ₁ and K ₂ to determine the range TAa of the throttle opening TA from the start of acceleration in which fuel increase control by asynchronous injection is performed. Here, TAao is preset to a value that increases as the throttle opening speed △TA increases, as shown in Figure 7, but the specific value is determined by experimentation according to the characteristics of the engine used. determined according to Also, here
The constants K ₁ and K ₂ used to calculate TAa are coefficients for correcting the throttle opening range from the start of acceleration in which fuel increase control by asynchronous injection should be performed based on the state of the engine 1, and For example, as shown in FIGS. 8 and 9, the value K ₁ is determined according to the engine cooling water temperature indicating the warm-up state of the engine 1.
and a value K ₂ determined according to the rotation speed of the engine 1. Step 280 following step 260
Now, step to the value TAa obtained in step 260.
The process of calculating TAb is performed by adding the previous throttle opening degree TAi _-1 read in step 200. The value TAb determined in step 280 is the upper limit value of the throttle opening range in which fuel increase control is performed by asynchronous injection during acceleration. In the next step 290, the flag FLAG is set to 1, and in the following step 300, the step 220 is set as △TAin.
The throttle opening speed ΔTA obtained in step 280 and the upper limit value TAb obtained in step 280 are each stored in predetermined areas of the memory unit 106. The above series of processing, steps 260, 280,
After 290 and 300, processing continues to step 310.

On the other hand, when the determination at step 250 is "NO", that is, when the flag FLAGX≠0, the process moves to step ₂₇₀ , where it is determined whether .DELTA.TA-.DELTA.TAin.ltoreq.T0. Here, △TA is the throttle opening speed at the time this control routine is executed (obtained in step 220), and △TAin is the throttle opening speed when this control routine was executed last time (previous processing (in step 300, it is stored in a predetermined area of the memory unit 106), and in step 270, it is determined whether the difference between the two is less than or equal to a predetermined value _T0 . If the judgment in step 270 is "NO", the current throttle opening speed is △
When TA exceeds the previous value △TAin predetermined amount T ₀ or more, it is determined that the opening speed of the throttle valve 9 is further increased and greater acceleration is required, so the processing is performed. The process moves to step 260 described above, and the process of setting the throttle opening range, that is, the upper limit value TAb, for which fuel increase control is performed by asynchronous injection is performed again. If the determination in step 270 is "YES" and there is no significant change in the opening speed of the throttle valve 9, the process proceeds to step 320, where the throttle opening TAi read in step 200 of this control routine is The upper limit value obtained in step 280 in the last executed control routine and stored in a predetermined area of the memory unit 106
A determination is made whether it is smaller than TAb. In the determination at step 320, if TAi≦TAb holds true, it is determined that the throttle opening does not exceed the upper limit of the throttle opening for performing asynchronous injection, and the process proceeds to step 310. On the other hand, if the judgment in step 320 is "NO", that is, if TAi≦TAb does not hold (that is, if TAi>TAb), then the throttle opening TAi exceeds the range in which fuel increase control is performed by asynchronous injection. Since this has been determined, the process moves to step 240, where the flag is flagged.
After setting FLAGX to 0, execute this control routine in B
exit and exit.

The processing of this control routine (i.e., the step
200 to step 230, step 250, step
260 and processing of steps 280 to 300)
This control routine process (i.e., step
200 to 230, steps 250, 270, and 320), the process returns to step 310.
In step 310, throttle opening speed △
Based on TA, a process of calculating an asynchronous fuel injection amount TAsy is performed. TAsy is TAsy=α×
It is calculated as △TA + β, where α and β are constants determined by the characteristics of the intake pipe pressure sensor 2 that detects the intake air amount, as shown by the broken line S in Fig. 1, that is, its response delay, etc. It is. In the following step 330, based on the asynchronous fuel injection amount TAsy obtained in step 310, the fuel injection time control counter unit 109 controls the fuel injection valve 4 (4).
a, 4b, 4c, 4d, 4e, 4f) are set to values corresponding to the opening times. The counter unit 109 starts counting down when the data is set, and continues counting down the power amplifier 1 until the value reaches 0.
Since the fuel injection valve 4 is opened via the fuel injection valve 10, fuel injection is performed without synchronization with the rotation of the engine 1, and fuel increase control is performed.

After performing the process of step 330, the process exits to B and ends this control routine.

In this embodiment configured as above,
The opening degree TAi of the throttle valve is read every 20 msec to detect the opening speed △TA, and when the opening speed △TA is above a predetermined value, the throttle valve is opened to increase the amount of fuel by asynchronous injection. If the actual throttle valve opening TAi is within the calculated range TAb,
The fuel amount TAsy to be injected into the engine 1 is determined according to the throttle opening speed ΔTA, and the fuel injection is performed without synchronization with the rotation of the engine to perform fuel increase control. Therefore, asynchronous injection of fuel is performed only from the start of acceleration to a predetermined throttle opening determined according to the opening speed of the throttle valve, so that the intake pipe pressure sensor 2 that detects the intake air amount is It is possible to prevent the problem of the air-fuel ratio becoming overly lean due to a response delay, and to maintain good drivability even immediately after the start of acceleration. In addition, fuel injection is not synchronized with engine rotation and is carried out immediately when the start of acceleration is detected by a change in the opening degree of throttle valve 9. Therefore, for synchronous injection, fuel increase control is performed immediately after the start of acceleration is detected. The problem of having to wait until the time of fuel injection, during which time the air-fuel ratio becomes over-lean and drivability deteriorates, is also satisfactorily resolved.

In this example, an intake pipe pressure sensor was used to detect the amount of intake air, but even when an air flow meter is used to detect the flow rate of intake air, there is a response delay due to inertia in the air flow meter, so this example was used to detect the amount of intake air. When using the example fuel supply control device for an internal combustion engine,
A similar effect can be achieved. Furthermore, in this embodiment, a 6-cylinder engine in which synchronous injection is performed has been described, but the present invention can also be applied to other multi-cylinder engines such as 4-cylinder or 8-cylinder engines. There is no problem in applying the present invention to a multi-cylinder engine that performs independent fuel injection, or to a multi-cylinder engine that supplies fuel to each cylinder by a method other than fuel injection. Furthermore, in this example, the opening degree of the throttle valve for performing asynchronous injection was determined based on the throttle opening speed and corrected using correction coefficients K ₁ and K ₂ depending on the engine cooling water temperature and engine rotation speed. However, the correction may also be made using the opening degree of the throttle valve at that time, the gear position of the transmission, etc. In this case, for example, using the gear position of the transmission means changing the amount of fuel increased by asynchronous injection depending on the output torque to be extracted from the engine, which improves drivability during acceleration. It has the advantage of being able to be maintained well.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way.
It goes without saying that the invention can be implemented in various ways without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, when the start of acceleration is detected, the maximum throttle opening is set according to the throttle opening and opening speed. Then, in an accelerated state where the opening speed is higher than a predetermined value,
Only when the throttle opening is less than or equal to the maximum throttle opening, the fuel injection amount is increased in accordance with the opening speed. Therefore, the increase correction is not performed in a state where the throttle valve opens to some extent after the start of acceleration and the response delay in the intake air amount becomes small. Moreover, control can be easily realized since it is only a comparison with a set value. Therefore, it has the excellent effect of being able to prevent deterioration of the exhaust system due to over-richness of the air-fuel ratio with simple control.

[Brief explanation of the drawing]

Fig. 1 is a graph for explaining the response delay that exists in the detection of intake air amount, Fig. 2 is a basic configuration diagram of the present invention, and Fig. 3 is a diagram of an internal combustion engine according to an embodiment of the present invention and its peripheral equipment. FIG. 4 is a block diagram showing the control system centered on the electronic control circuit, and FIG. 5 is a schematic block diagram showing the configuration.
FIG. 6 is a flowchart showing the control of the embodiment; FIG. 7 is a map giving the throttle opening TAao from the start of acceleration corresponding to the throttle opening speed ΔTA; FIG. The figure is a graph explaining the value of the correction coefficient _K1 , and FIG. 9 is a graph regarding the correction coefficient _K2 . 1...Engine, 2...Intake pipe pressure sensor, 4
... Fuel injection valve, 8 ... Rotation angle sensor, 10 ...
Throttle opening sensor, 20... electronic control circuit,
100...CPU.

Claims (1)

[Scope of Claims] 1. Throttle opening detection means for detecting the throttle opening of a throttle valve that adjusts the amount of air taken into the internal combustion engine; Opening speed detection means for detecting the opening speed of the throttle opening. , acceleration opening detection means for detecting the start of acceleration of the internal combustion engine; and when the acceleration start detection means detects the start of acceleration, setting a maximum throttle opening according to the throttle opening and the opening speed. Maximum throttle opening setting means; when the opening speed is above a predetermined value and the throttle opening is below the maximum throttle opening, the amount of fuel supplied is increased in accordance with the opening speed, and the opening speed is set to a predetermined value. 1. A fuel supply control device for an internal combustion engine, comprising: a fuel supply means that does not increase the amount of fuel supplied when the throttle opening is less than the maximum throttle opening or when the throttle opening is greater than the maximum throttle opening. 2. The fuel supply means includes: a synchronous supply means that supplies a fuel supply amount according to the operating state in synchronization with the rotation of the internal combustion engine; and when the throttle opening degree and the opening angle are in the additive fuel supply range. , and asynchronous supply means for supplying an additional fuel supply amount according to the opening speed at a timing different from the supply timing by the synchronous supply means. Fuel supply control device. 3. The internal combustion engine according to claim 1 or 2, wherein the maximum throttle opening setting means includes a correction means for correcting the maximum throttle opening according to the operating state of the internal combustion engine. Engine fuel supply control device.