JPH0461178B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a control method for an electronically controlled fuel injection device, and more specifically, a method for controlling an electronically controlled fuel injection device, and more specifically, a method for controlling an electronically controlled fuel injection device, and more specifically, a method for controlling an electronically controlled fuel injection device, and more specifically, a method for controlling an electronically controlled fuel injection device. The present invention relates to a control method for a fuel injection device that increases and injects a predetermined amount of fuel in addition to the normal basic injection amount that is injected accordingly.

[Prior Art] In an automobile internal combustion engine equipped with an electronically controlled fuel injection device, when the load changes from low load to high load, the amount of fuel injected according to the operating state, that is, the basic injection amount, In addition to this, a certain amount of fuel is increased (hereinafter referred to as power increase). The air-fuel ratio (the weight ratio of air and fuel in the air-fuel mixture sent to the cylinders) is made rich (the fuel is richer than the ideal air-fuel ratio) to maintain high output and reduce vehicle speed. Preventing.

However, conventionally, the increase value due to such power increase, ie, the power increase value, is always a constant value. Therefore, immediately after the load changes as shown in Figure 1A, for example, the throttle opening indicating the degree of opening of the throttle valve increases, or immediately after the intake pipe negative pressure decreases, a certain amount as shown in Figure 1B increases. Since an increased amount of fuel is injected with a value of , the following problems arise. That is, as shown in FIG.
It is heated by passing through an intake manifold, etc., and is made to have a higher temperature than the outside air. However, as the load increases and the amount of intake air increases,
The intake port, intake manifold, etc. are cooled, so the intake air is not heated, and the temperature of the intake air gradually approaches the outside temperature. As a result,
As shown in Figure 1D, when the intake air temperature is relatively high, the air density is low, so when power is increased, the air-fuel ratio will be lower than the target air-fuel ratio shown by the dashed line in Figure 1D. Furthermore, the fuel becomes rich (over-rich), and emissions are increased by that amount, and fuel is wasted to the extent that it becomes over-rich, resulting in a problem of worsening fuel efficiency.

[Objective of the Invention] An object of the present invention is to control how to increase the amount of fuel injected in an amount greater than the basic injection amount when the load applied to the internal combustion engine changes from low load to high load. Therefore, it is an object of the present invention to provide a control method for a fuel injection device that solves the above-mentioned problem that the air-fuel ratio becomes overrich immediately after a load change, resulting in deterioration of emissions and fuel efficiency.

[Configuration of the Invention] The configuration of the present invention to achieve the above object is as shown in the flowchart of FIG. In addition to calculating the basic injection amount, (P2) detects the load applied to the internal combustion engine, and when the load is high, (P3) adds a fuel increase value to the basic injection amount,
In the control method for a fuel injection device that increases the amount of fuel injected from the fuel injection valve, (P4) when the load changes from a low load to a high load, (P5) the fuel increase value is adjusted to a predetermined value set in advance. (P6) Until a predetermined period of time elapses,
The gist of the present invention is a method of controlling a fuel injection device, characterized in that the fuel increase value is gradually increased.

[Example] The present invention will be described below by giving examples and referring to the drawings.

First, FIG. 3 is a schematic system diagram showing a four-stroke, four-cylinder internal combustion engine and its peripheral equipment according to the first embodiment to which the method of the present invention is applied.

1 is an engine, 2 is a piston, 3 is a spark plug, 4 is an exhaust manifold, 5 is an oxygen sensor provided in the exhaust manifold 4 and detects the residual oxygen concentration in exhaust gas, 6 is provided for each cylinder, respectively. a fuel injection valve for injecting fuel; 7 is an intake manifold; 8 is provided in the intake manifold 7;
1 is an intake air temperature sensor that detects the temperature of intake air sent to the engine body 1; 9 is a water temperature sensor that detects the engine cooling water temperature; 10 is a throttle valve;
1 is a throttle position sensor that is linked to the throttle valve 10 and outputs a signal according to the opening degree of the throttle valve 10; 12 is a bypass passage that is an air passage that bypasses the throttle valve 10; 13;
Reference numeral 14 represents an idle speed control valve ISCV that controls the opening area of the bypass passage 12 to control the idle rotation speed, 14 represents an air flow meter that measures the amount of intake air, and 15 represents an air cleaner that purifies the intake air.

Further, 16 is an igniter that is equipped with an ignition coil and outputs the high voltage necessary for ignition, and 17 is a device that is linked to a crankshaft (not shown) and distributes the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder. A triviewer 18 is installed within the distributor 17 and is connected to the distributor 1.
7, a rotation angle sensor that outputs 24 pulse signals per one rotation of the crankshaft, 19 a cylinder discrimination sensor that outputs one pulse signal per one revolution of the distributor 17, and 20 an electronic control circuit. each represents.

Further, 21 indicates a passage through which air flows bypassing the throttle valve when the engine is cold, that is, a first idle bypass passage. And 22
indicates an air valve that controls the amount of air passing through the first idle bypass passage 21. Note that the air valve 22 operates to open the first idle bypass passage 21 in order to secure the engine rotational speed necessary for warm-up operation when the engine is cold.

Next, FIG. 4 shows a block diagram of the electronic control circuit 20.

30 is a central processing unit (hereinafter simply referred to as CPU) that inputs and calculates data output from each sensor according to a control program, and performs processing to control the operation of various devices such as the fuel injection valve 6 and ISCV 13. ), 31 is a read-only memory (hereinafter simply referred to as ROM) in which data such as the control program and a map for calculating the fuel injection amount is stored, and 32 is an electronic control circuit 2
33 is a random access memory (hereinafter simply referred to as RAM) in which data input to 0 and data necessary for arithmetic control are temporarily read and written; and 33 is necessary for subsequent engine operation even if a key switch (not shown) is turned off. Backup random access memory (hereinafter simply referred to as backup) is backed up by a battery to hold learning value data, etc.
It's called RAM. ), 34 is an input port (not shown), a waveform shaping circuit provided as necessary, a multiplexer that selectively outputs the output signal of each sensor to the CPU 30, an A/D converter that converts an analog signal into a digital signal, , etc., respectively. 35 is provided with an output port in addition to an input port (not shown), and a fuel injection valve 6, ISCV 13, etc. are connected to the CPU 3 as necessary.
An input/output section 36 is provided with a drive circuit etc. to drive according to a control signal of 0, and 36 is a CPU 30 and a ROM.
31 and the like and the input section 34 and the input/output section 35, and each bus line through which each data is sent is shown.

Control of the fuel injection valve 6 by the electronic control circuit 20 is performed by outputting to the fuel injection valve 6 a pulse signal that remains at a low level for a period of time corresponding to the calculated fuel injection amount.

Next, the control program which is the main part of this embodiment will be explained with reference to the flowchart of FIG.

This program represents a "power increase processing" routine and is stored in the ROM 31 as a part of the main control program or as a subroutine.

Then, in a known basic injection amount calculation routine (not shown), it is calculated based on the engine rotation speed N detected by the rotation angle sensor 18 etc. and the intake air amount Q detected by the air flow meter 14. Furthermore, after the basic injection amount TP of fuel is determined as appropriate based on the detection signals of the oxygen sensor 5 and the water temperature sensor 9, the processing of this program is executed.

When the processing of this program is started, first in step 50 it is determined whether the conditions for increasing the power are satisfied. The condition for increasing power refers to a case where the load applied to the engine 1 changes from a low load to a high load, and specifically, the throttle opening detected by the throttle position sensor 11 or the intake manifold A negative pressure sensor is provided at 7, and a load change is determined based on the intake pipe negative pressure detected by this negative pressure sensor.

If it is determined in this step 50 that the throttle opening (or intake pipe negative pressure) is in a loaded state, it is assumed that the power increase condition is satisfied and the process moves to the next step 60, and on the other hand, the power is increased. If it is determined that the load is unnecessary and low, the power increase flag F, which is a flag indicating that power should be increased, is reset to "O" through the process of step 70, and the timer value t is set to "O".
After resetting to , the processing of this routine ends.

In the process of step 60, which is performed when it is determined in step 50 that the power increase condition is satisfied, the power increase flag F has already been set to "1".
It is determined whether the increase flag F is set to "1", that is, "NO".
If it is determined that this is the case, the process moves to step 80. On the other hand, if the increase flag F is set to ``1'', that is, if it is determined as ``YES'', step 80 is not performed and step 90 described below is performed.
Shift to processing.

In step 80, since the processing of this step is performed only after the load applied to the engine 1 changes to a high load, the increase flag F is set to "1" and a soft timer etc. that is timed by the program is set. A timer is started and the process moves to the next step 90. Note that the timer may be a hard timer using a counter element or the like.

In step 90, it is determined whether or not the current timer value (time value) is greater than a preset value _t1 . If "NO", that is, "t≦ _t1 ", the process of step 100 to move to. Note that if the timer has just been started in step 80, the determination in step 90 will naturally be "NO".

In step 100, the power increase value K is set to the smallest value _K1 as shown in FIG. 6A, and the process proceeds to step 160, which will be described later.

On the other hand, if it is determined in step 90 that the timer value t is greater than _t1 , then step 110
Shift to processing.

In step 110, it is determined whether or not the timer value is greater than a preset value _t2 . If "NO", that is, "t≦ _t2 ", step 12 is performed.
Shift to process 0.

In the process of step 120, the power increase value K is set to a value _K2 which is slightly larger than _K1 , as shown in FIG. 6A, and then the process proceeds to step 160, which will be described later.

On the other hand, in step 110, the timer value is t ₂
If it is determined that the
Shift to process 0.

In step 130, it is determined whether the timer value is greater than a preset value _t3 ;
If "NO", that is, "t≦t ₃ ", the process moves to step 140.

Then, in step 140, the power increase value K is set to a value _K3 , which is larger than the above-mentioned _K2 , as shown in FIG.

On the other hand, in step 130, the timer value t is
If it is determined that it is greater than _t3 , the process moves to the next step 150.

In step 150, the power increase value K is set to the largest value _K4 as shown in FIG. Furthermore, K ₄
For example, a value that increases the basic injection amount by 12 to 15% is appropriately selected, and a value of about 2 to 4 seconds is appropriately selected as the timer value _t3 .

In the following step 160, a new power increase value K is added to the basic injection amount TP calculated by a basic injection amount calculation routine (not shown) as a new basic injection amount TP, and the processing of this program is ended.

Then, in an injection routine (not shown), fuel in an amount represented by TP is injected from the fuel injection valve 6.

Next, the operation of this embodiment will be explained.

When the load applied to the engine 1 changes from a low load to a high load through the processing of the control program described above, the power increase value will change as the intake air temperature increases after the load change, as shown in the graphs in Figure 6 A and B. It gradually increases with the passage of time in accordance with the decrease, and reaches a predetermined value _K4 after the elapse of time indicated by _t3 . After that, the power increase value remains constant while the high load condition continues.
K remains at ₄ .

As a result, as shown in Figure 6 C, the air-fuel ratio quickly becomes rich to the target value after the load change, and as in the conventional example shown in Figure 1 D, the air-fuel ratio once becomes overrich after the load change. The target value will not be reached, the emissions will not increase unnecessarily, and there will be no wasteful consumption of fuel.

Incidentally, if the timer value is further divided into smaller parts and the power increase value K is gradually increased more precisely, the above-mentioned effect will be even greater.

Next, a second embodiment of the present invention will be explained along with a control program representing the main part thereof. Note that the engine and its peripheral devices used in the second embodiment are the same as those in the previous embodiment, so a description thereof will be omitted.

FIG. 7 is a flowchart showing the control program of the second embodiment. The difference from the control program of the first embodiment in FIG. 5 is that in the first embodiment, the power increase value K is increased in a stepwise manner after a load change, whereas in this embodiment, the power increase value K is increased after a load change. K is made to increase smoothly.

In the flowchart of the control program shown in FIG. 7, steps 50, 60, 70, 80, 130,
The processes shown in steps 150 and 160 are the same as in the control program of the first embodiment, and steps 90, 100,
The processing shown in step 170 is performed instead of the processing shown in steps 110, 120, and 140.
Therefore, explanations of the same steps as shown in the flowchart of FIG. 5 will be omitted.

In this program, step 170 is a process of calculating the power increase value K according to the function K=F(t)=at+K ₁ (a is a coefficient and K ₁ is a constant), taking into account changes in the intake air temperature, for example. The power increase value K is increased according to a straight line having a constant slope until the time indicated by _t3 elapses after the load is changed by the processing of step 130 and step 170.

As a result, in this embodiment, as shown in FIG. 8, the power increase value K is set to K ₁ immediately after the load change, increases smoothly thereafter, and returns to a constant value K ₄ after the time t ₃ has decreased. It is said that

Therefore, the air-fuel ratio shifts more smoothly to the target value than in the first embodiment, and the emission and
Fuel efficiency is further improved compared to the first embodiment.

Incidentally, in step 170, the function F(t) may be one that represents a curve that conforms to changes in the intake air temperature, and furthermore, the value detected by the intake air temperature sensor 8 may be used instead of the variable at time t. may be a variable.

[Effects of the Invention] As explained above, in the present invention, when the internal combustion engine changes from low load to high load, the fuel increase value for the basic injection amount is set to a predetermined value, and the fuel is maintained until a predetermined period has passed. Gradually increase the increase value.

Therefore, immediately after the internal combustion engine changes from low load to high load, that is, when the intake air temperature is relatively high and the air density is low, the fuel increase value for the basic injection amount is set to a relatively low value, and then As the intake air temperature decreases (that is, as the air density increases) due to high-load operation of the internal combustion engine, the fuel increase value is increased, and unlike conventional methods, the fuel increase value is increased at the same time as the load changes. Compared to the case where fuel is injected by increasing the amount of fuel, the air-fuel ratio does not become overrich transiently due to changes in intake air temperature due to changes in load. Therefore, the emission is improved by that amount, and the effect of improving fuel efficiency can be obtained.

Furthermore, after a load change, the air-fuel ratio smoothly shifts to the target value at high load, so there is no disturbance in the output torque, improving driveability, and there is no need for special equipment, making it easier to use than conventional equipment. There are also secondary effects that can be easily applied to

[Brief explanation of drawings]

Figure 1 A to D show changes in throttle opening (intake pipe negative pressure), power increase value according to the conventional example, intake air temperature, and air-fuel ratio according to the conventional example when the load changes from low load to high load, respectively. 2 is an explanatory diagram showing the configuration of the present invention, FIG. 3 is a schematic system diagram showing the engine and its peripheral equipment of the first embodiment to which the present invention is applied, and FIG. 4 is the same electronic control circuit. FIG. 5 is a flowchart showing a control program which is the main part of the first embodiment, FIG. 6 A to C are graphs explaining the operation of the first embodiment, and FIG. FIG. 8 is a flowchart showing a control program which is a main part of the second embodiment, and a graph showing the operation of the second embodiment. 1... Engine (internal combustion engine), 6... Fuel injection valve, 8... Intake temperature sensor, 10... Throttle valve, 11... Throttle position sensor, 2
0...Electronic control circuit, 30...CPU.

Claims (1)

[Scope of Claims] 1. Calculates the basic injection amount of fuel injected from the fuel injection valve of the fuel injection device according to the operating state of the internal combustion engine, and detects the load applied to the internal combustion engine, and determines whether the load is In a control method for a fuel injection device, in which, when the load is high, a fuel increase value is added to the basic injection amount to compensate for an increase in the amount of fuel injected from the fuel injection valve, when the load changes from a low load to a high load. ,
A method of controlling a fuel injection device, characterized in that the fuel increase value is set to a predetermined value, and the fuel increase value is gradually increased until a predetermined period of time elapses thereafter.