JPS61123727A - Fuel injection quantity controller for internal-combusion engine - Google Patents

Abstract

PURPOSE:To keep off any drop in output torque of an engine, by checking the performance of fuel increment compensation when a fundamental injection quantity of fuel is more than the specified value even in the case where a suction quantity detection value has varied in a suction reducing direction at more than the specified variation rate. CONSTITUTION:There is provided with a fundamental injection quantity setting device M5 which sets a section quantity Q to be detected by a suction quantity detecting device M14 installed at the upstream side of a throttle valve M3 inside a suction pipe M2 of an internal-combusion engine M1 and a fundamental injection quantity Tp according to engine load Q/N to be found out of an engine speed N. In addition, when the suction quantity Q has varied in a suction quantity reducing direction at more than the specified variation rate, there is provided with an injection quantity increment compensating device M6 which compensates the fundamental injection quantity Tp for increment. And, at the above-mentioned, additionally there is provided with a comparatively judging device M7 which judges whether the fundamental injection quantity Tp is more than the specified value or not, and when the Tp is more than the specified value, increment compensation for the injection quantity by the compensating device M6 is controlled so as not to be performed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention detects the intake air amount using a vane type air meter, and uses the intake air amount as one parameter to adjust the fuel injection amount to 1.
Regarding the fuel injection Dυlll1 device for an internal combustion engine, especially when the detection signal of the air 70 meter does not correspond to the actual intake air amount due to sudden closing of the throttle valve, it is possible to perform a good fuel injection control on the fuel for the internal combustion engine. This invention relates to an injection amount control device.

[Prior Art] Conventionally, a so-called vane-type air 70 meter, which is installed upstream of a throttle valve in the intake pipe of an internal combustion engine (hereinafter also referred to as engine) and rotates according to the amount of intake air, is used to measure the amount of intake air. The fuel injection amount III a ! is detected and the fuel injection amount is controlled according to the load condition of the internal combustion engine obtained by using the detected intake air amount as one parameter. There is a place.

However, with the vane type air 70 meter mentioned above, if the throttle valve is suddenly closed by the driver's accelerator operation during deceleration, etc., the detection signal may show a value smaller than the actual intake air amount. .

In other words, as shown in FIG. 6, due to the inertia of the air that had passed through the dam plate 53 of the air flow meter 52 before the throttle valve 51 suddenly closed, a certain amount of air is instantaneously generated when the throttle valves 51 to 51 are suddenly closed. of air flows into the part A, the pressure in the part A rises, a force in the direction of arrow B is applied to the dam plate 53, the dam plate is displaced to the side with a smaller amount of air, and as a result, from the air 70 meter 52 Since a detection signal different from the intake air amount of the engine is generated and returns to the normal state after a certain period of time, the detection signal becomes smaller than the actual intake air amount when the throttle valve is suddenly closed. The time chart 1r-1 consists of the opening degree of the throttle valve 51 (A), the actual intake air amount that changes with respect to it (B), and the detection signal of the air flow meter 52 (C), which shows the state in the figure.
- indicates.

Therefore, in the past, as a countermeasure, for example,
As disclosed in Japanese Patent No. 4612, when the detection signal of the air flow meter changes by a predetermined change rate or more in the direction of decreasing intake air amount, the fuel injection amount determined based on the detection signal from the air 70 meter is changed. It is designed to compensate by increasing the amount.

[Problem to be solved by the invention 1 However, as mentioned above, the fuel injection t is determined based on the detection signal of the air 70 meter.
If the JJ amount is increased, the amount of fuel injection (6) will be increased not only when the throttle valve is suddenly closed, but also due to intake pulsation during high engine load operation, and when the engine is under high load, the fuel injection (6) will be increased. A problem arises in that the fuel ratio becomes excessively rich, leading to a decrease in output torque.

Therefore, the present invention prevents the air-fuel ratio from becoming excessively rich during high-load engine operation by not performing the above-mentioned increase correction during high-load engine operation, and also prevents the air-fuel ratio from becoming excessively rich during high-load engine operation. It is an object of the present invention to provide a fuel injection end control device for an internal combustion engine that detects based on the above, thereby easily detecting engine high load operation, and yet preventing the output torque at that time from decreasing.

[Means for Solving the Problems] As shown in FIG. 1, the configuration of the present invention for achieving the above object is as follows: A throttle valve M3 is provided upstream of an intake pipe M2 of an internal combustion engine M1, and the intake air amount is controlled by a throttle valve M3. an intake air amount detecting means M4 which rotates and displaces accordingly; and a basic injection body setting means M5 which sets a basic injection amount of fuel to be supplied to the i-injection M1 by using the detection signal of the intake air amount detecting means M4 as one parameter. , the intake air amount detection means M
an injection amount increase correction means M6 for increasing the set basic injection amount when the detection signal of No. 4 changes in the intake air amount decreasing direction by a predetermined rate of change or more; In a fuel injection amount control device for an internal combustion engine that controls an injection amount, a comparison determination means M for determining whether the basic injection amount is equal to or greater than a predetermined value.
7 is provided, and if the basic injection M is greater than or equal to the predetermined value 11I'1,
The gist of the present invention is a fuel injection amount control device for an internal combustion engine, characterized in that the injection amount increase correction means M6 is configured not to perform increase correction of the injection amount.

[Function] Here, the intake air amount detection means M4 is for detecting the amount of air taken into the internal combustion engine M1, and as mentioned above, it is rotated and displaced according to the intake air amount, and its displacement This is a so-called vane-type air 70 meter that outputs a detection signal according to the

The basic injection Il setting means M5 sets the basic injection amount of fuel to be supplied to the internal combustion engine M1 using the intake air amount detected by the intake air amount detecting means M4 as one parameter, and generally, Intake mQ and engine speed N,
Yuzumoto injection according to the required engine load Q/N.
JUffi is set. The basic injection amount is usually set as the opening time of the fuel injection valve.

Next, the injection amount increase correction means M6 is the intake air amount detection means M4.
The basic injection amount is corrected to increase when the detection signal of the throttle valve M3 changes in the intake air amount decreasing direction by a predetermined rate of change or more.
When the engine suddenly opens, the detection signal of the intake air amount detection means M4 indicates a value smaller than the actual intake air amount, so the basic injection amount determined based on the detection signal becomes a value corresponding to the actual intake air amount. This is to correct this. Incidentally, it is possible to detect that the detection signal of the intake air amount detection means M4 has changed by a predetermined change rate or more by directly observing the detection signal, but the basic injection amount is set by the basic injection It setting means M5. is set based on the detection signal, it may be detected from a change in the basic injection amount.

Further, the comparison determination means M7 includes the basic injection field setting means M5.
The high-load operation of the internal combustion engine M1 is detected by determining whether the basic injection amount of fuel set in is equal to or higher than a predetermined value; Then, in the present invention, the injection amount increase correction means M
6 is prohibited to prevent the air-fuel ratio from becoming excessively rich during high-load operation of the internal combustion engine.

Therefore, high-load operation of the internal combustion engine M1 can be easily detected from the basic injection amount set by the basic injection setting means M5, and during high-load operation, the detection result of the intake air amount detection means M4 is in the direction of decreasing intake air amount. Even if the injection amount changes by more than a predetermined rate of change, the injection amount increase correction means M6 does not perform an increase correction, and the air-fuel ratio does not become too rich and the output torque does not decrease.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

First, Fig. 2 shows a 4-cylinder 4-cycle gasoline engine equipped with the fuel injection amount control device of this embodiment and its surrounding Ml.
FIG.

In the figure, 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, and 6 is provided for each cylinder, respectively. 7 is an intake manifold; 8 is an intake air temperature sensor provided in the intake manifold 7 and detects the temperature of the intake air sent to the engine body 1; 9 is a water temperature sensor that detects the engine cooling water temperature. sensor, 10 is a throttle valve,
11 is interlocked with the throttle valve 10, and the throttle valve 1
A throttle position sensor outputs a signal according to the opening degree of 0, a bypass passage 12 is an air passage that bypasses the throttle valve 10, and an idle speed 13 controls the opening area of the bypass passage 12 to control the idle rotation speed. A control valve (rscV), 14 represents an air 70 meter for measuring the amount of intake air, and 15 represents an air cleaner for purifying 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 distributor 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. , 18
19 is a rotation angle sensor that is installed in the distributor 17 and outputs four pulse signals for one revolution of the distributor 17, that is, two revolutions of the crankshaft. 19 is a cylinder discrimination sensor that outputs one pulse signal for one revolution of the distributor 17. The sensor and 20 each represent an electronic control circuit.

Next, FIG. 3 shows a block diagram of the electronic control circuit 20. As shown in FIG.

30 in the figure is a central processing unit (C
PU), 31 is a read-only memory (ROM) in which data such as the υ control program and a map for calculating the ignition advance angle are stored, and 32 is a read-only memory (ROM) that stores data input to the electronic control circuit 20 and data necessary for calculation control. Random access memory (RAM), which is temporarily read and written, 33 is air 7
The fuel injection valve 6 receives the detection signal output from the 0 meter 14 and the rotation angle sensor 18 and corresponds to the basic injection amount of fuel.
34 is a waveform shaping circuit, a multiplexer that selectively outputs the output signal of each sensor to the CPU 30, and an A/D converter that converts analog signals into digital signals. , etc., 35 is a pulse input port for inputting pulse signals from rotation angle sensor +J18, cylinder discrimination sensor 19, etc., 36 is a fuel injection valve 6, igniter 16, etc. which are calculated and outputted by CPU 30. An output port 37 receives a drive control signal and outputs a drive signal to the fuel injection valve 6, igniter 16, etc., and is a pass line that connects each of the above components except the basic injection pulse generation circuit 33 and sends various data.

In this electronic control circuit 20, the pulse width (hereinafter referred to as basic injection pulse width) TP of the pulse signal output from the basic injection pulse generation circuit 33 is determined by the oxygen sensor 5, the intake air temperature sensor 8, the water temperature sensor 9, , the throttle position sensor 11, the air 70 meter 14, etc., and control the amount of fuel supplied to the engine 1 to a value corresponding to the operating state of the engine 1. Drive control of the l5CV13, igniter 16, etc. is executed depending on the state, and next, the basic injection pulse width TP, which is the main process related to the main injection executed by this electronic control circuit 20, is executed. The correction calculation process will be explained.

The basic injection pulse generation circuit 33 outputs a pulse signal having a basic injection pulse width TP corresponding to the basic fuel injection amount in response to the detection signals of the air 70 meter 14 and the rotation angle sensor 18, as described above. , as shown in Figure 4,
Branching is performed based on the rise of the engine 1 rotation signal (every 180°C) output from the rotation angle sensor 18,
This is a known circuit that charges and discharges a capacitor at the ON-OFF timing of the frequency-divided signal to generate the basic injection pulse width TP. Here, the slope of discharge in the capacitor charging/discharging waveform is determined from the opening degree signal of the intake dam plate of the air flow meter 14 output from the air 70 meter 14,
The basic pulse width TP is set by this discharge time. For example, if the intake air amount determined according to the detection signal from the air flow meter 14 increases, the capacitor discharge time becomes longer as shown by the dotted line, and the basic injection pulse width T
P also becomes larger.

FIG. 5 is a flowchart showing a calculation process for correcting the basic injection pulse width TP, which is executed by the electronic control circuit 20.

As shown in the figure, when the process is started, step 101 is first executed, and the basic injection pulse width TP of the pulse signal output from the basic injection pulse generation circuit 33 is read, and the process proceeds to primary step 102. In step 102, the annealed pulse width T obtained during the previous processing in step 111, which will be described later, and stored in the RAM 24 in step 113.
The PN is read and the process moves to the following step 103.

In step 103, it is determined whether the difference (TPN-TP) between the basic injection pulse width TP and the annealed pulse width TPN read in steps 101 and 102 is smaller than "0", that is, whether the engine 1 is in a deceleration state. It is determined whether the engine 1 is in a deceleration state and (TPN-TP)≧
If it is determined that the basic injection pulse width TP is 0, the process moves to the subsequent step 104 and the degree of decrease in the basic injection pulse width TP is determined.

That is, in step 104, the basic injection pulse width TP set based on the detection signal from the air flow meter 14 is
By determining whether the detection signal of the air 70 meter 14 has changed by a predetermined change rate or more in the direction of decreasing intake air by determining whether or not has changed by a predetermined change amount or more between the previous processing and the current processing. In this embodiment, whether (TPN-TP-256> is smaller than o or not,
That is, the amount of change in the basic injection pulse width TP is 256 cμsec.
, ] or more is determined. And (TP
If N-TP-256)≧0, it is determined that the detection signal of the air flow meter 14 has changed rapidly in the direction of decreasing intake air, and the process moves to the following step 105.

In step 105, the calculation result of (TPN-TP-256) obtained in step 104 is stored in the RAM 3.
2 is stored as a DLTPN in a predetermined area, and the process proceeds to step 106.

Then, in step 106, the stored DL
For example, it is determined whether the value of TPN is larger than 2048 Cu5ec, ], and if DLTPN>2048, the process moves to step 107 and DLTPN is set to 2048 Lt.
tsec, ] and proceed to step 108, while if DLTPN≦2048, proceed directly to step 1.
Move to 08.

In step 108, the DLTP obtained in step 105 or set in step 107 is
The value of N is divided by 2048 [μsec, ] t, and the resulting value is stored as C in a predetermined area of the RAM 32. The process then proceeds to step 109, where the value of C is multiplied by a constant 0.8 and stored in a predetermined area of the RAM 32 as the increase correction LliED when the throttle valve is suddenly closed.

When the increase correction 1 [D is set in this way, the process moves to the subsequent step 110, and the basic injection pulse width TP read in the step 101 is now 2500 [μse
c, ], that is, whether the engine 1 is operating under high load or not. If TP≦2500, it is determined that the engine 1 is not operating under high load and the process moves to step 111. do.

On the other hand, if TPN>2500 and it is determined in step 110 that engine 1 is operating under high load, it is determined in step 103 that (TPN-TP) is not in the deceleration state. or if (TPNTP-256)<O in step 104 and it is determined that the detection signal of the air 70 meter 14 is not changing by a predetermined change rate or more in the direction of decreasing intake air, step 112 is executed, the increase correction raD is set to "0", and the process moves to the subsequent step 111.

In step 111, the annealed injection pulse width TPN is calculated using the following formula, which uses the annealed injection pulse width TPN obtained in the previous process and the basic injection pulse width TP read in this step 101 as parameters. , then step 1
At step 13, this value is stored in a predetermined area of the RAM 32.

Then, in the next step 114, the oxygen sensor 5,
Based on various detection signals from the intake air temperature sensor 8, water temperature sensor 9, throttle position sensor 11, etc., an increase or decrease correction 11E for cases other than when the throttle is partially closed is calculated, and the process proceeds to step 115. The calculation of this correction value E is based on the amount of fuel increased at startup, l! Increased amount, JTL during acceleration,
Correction values for executing the warm-up acceleration device, air-fuel ratio compensation, intake temperature correction, etc. are calculated, and since they are conventionally known, detailed explanations will be omitted.

After the fuel increase correction value when the throttle valve is suddenly closed and the fuel correction value E under other operating conditions are determined in this way, the subsequent step 115 is executed, and the step 1 described above is performed.
The basic injection pulse width TP read in step 01 is corrected using the following formula %, the injection pulse width TAU to be actually output to the fuel injection valve 6 is calculated, and the processing of this routine is temporarily terminated. . Here, TAtJV is the invalid injection pulse width.

In this way, in the fuel injection amount control device of this embodiment,
Air 70 output from the basic injection pulse generation circuit 33
The amount of change in the basic injection pulse width TP corresponding to the basic injection layer of fuel set according to the detection signal of the meter 14 with respect to the rounded pulse width TPN is calculated, and the amount of change is set to a predetermined value (
256 [μsec, ]), a sudden change in the detection signal of the airflow meter 14 in the direction of decreasing intake air volume is detected, and at that time, an increase correction 1 [D] is set in response to the change m. . Therefore, the throttle valve 10 becomes urgently involved.
Even if the detection signal from the airflow meter 14 has a value that does not correspond to the actual intake air amount, the amount of fuel supplied to the engine 1 can be controlled to a value that approximately corresponds to the actual intake air amount, Misfires of the engine 1 can be prevented. In addition, high-load operation of engine 1 is performed in step 1 above.
In the process of 10, the basic injection pulse width TP is 2500 [μ5
eC1], and TP>25
When it becomes 00, even if the detection signal of the air 70 meter 14 suddenly changes in the direction of decreasing the intake air amount, the increase correction accuracy is set to ``0'' and the fuel amount is not increased accordingly. . Therefore, in response to changes in the detection signal of the air flow meter 14 that occur due to intake pulsation during high engine loads, the fuel is no longer compensated for by increasing the amount of fuel, and the air-fuel ratio becomes too rich during high engine loads, resulting in a decrease in output torque. There is nothing like that.

In this embodiment, the basic injection pulse width TP of the fuel is set by the basic injection pulse generation circuit 33, but the CPU 3 sets the basic injection pulse width TP using the intake IQ and engine speed NE as parameters.
It may be calculated within 0. Further, in this embodiment, a sudden change in the detection signal of the air 70 meter 14 in the direction of decreasing intake air amount is detected by the amount of change in the basic injection pulse width TP. Direct detection may also be performed using

[Effects of the Invention] As detailed above, in the fuel injection amount control device of the present invention, even when the detection signal of the intake air amount detection means changes in the intake air decreasing direction by a predetermined rate of change or more, , if the basic fuel @ trip, which is set according to the load condition of the internal combustion engine using the detection signal as one parameter, is equal to or higher than a predetermined value, the fuel increase correction is not performed. Therefore, it is possible to prevent the air-fuel ratio from becoming excessively rich and the output torque of the engine to decrease, and it is possible to obtain good drivability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 5 show an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing the engine of the embodiment and its peripheral equipment, and FIG. 4 is a time chart explaining the operation of the basic injection pulse generation circuit, and FIG. 5 is a correction of the basic injection pulse width TP executed by the electronic control circuit 20. Flowcharts showing arithmetic processing, FIGS. 6 and 7 are explanatory diagrams for explaining conventional problems, and FIG. 7 are time charts showing changes in the throttle opening degree (a), intake air amount (b), and detection signal (c) at that time. Ml...Internal combustion engine M2...Intake pipe M3.10.51...Throttle valve M4...Intake air amount detection means Mb...Basic injection port setting means M6...-Injection amount increase correction means M7. ... Comparison and determination means 1 ... Engine 14 ... Air 70 meter 18 ... Rotation angle sensor 30 ... CPU

Claims (1)

[Scope of Claims] An intake air amount detection means that is provided upstream of a throttle valve in an internal combustion engine intake pipe and rotates according to the amount of intake air, and a detection signal of the intake air amount detection means as one parameter. basic injection resetting means for setting a basic injection amount of fuel to be supplied to the engine; A fuel injection amount control device for an internal combustion engine that controls a fuel injection amount according to an operating state of the engine, comprising: an injection amount increase correction means that performs an increase correction; A fuel for an internal combustion engine, characterized in that a comparative judgment means is provided to determine the amount of fuel for an internal combustion engine, and the injection amount increase correction means does not perform an increase correction of the injection amount when the basic injection amount is equal to or higher than a predetermined value. Injection amount control device.