JPS61126338A - Fuel injection quantity control unit for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent deterioration of drivability from occurring regardless of sudden change in the intake air quantity, by defining the upper limit quantity of fuel injection according to the opening of a throttle valve. CONSTITUTION:An opening of the throttle valve of an internal-combustion engine M1 is detected by a throttle opening detecting means MA. The upper limit value of a quantity of fuel injection is determined depending upon the magnitude of an opening of the throttle valve obtained by the throttle opening detecting means MA. Owing to such a method, deterioration of drivability occurring due to sudden change in the intake air quantity can be prevented in the case of a control unit using a moving vane type intake air quantity sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection amount control device for an internal combustion engine, and in particular to a device for controlling the amount of fuel injection by detecting the intake air amount of the internal combustion engine using a moving vane type air flow meter. The present invention relates to a fuel injection amount control device for an internal combustion engine that calculates .

[Prior Art] Conventionally, fuel injection amount III improves fuel efficiency and emissions by supplying an optimal amount of fuel to an internal combustion engine.
m devices are provided.

Fuel injection ml II II device with a moving vane type air flow meter is one of them! Using a moving vane type air flow meter that detects the intake air flow rate by displacing a measuring member by the intake air of the Il circle and converting the amount of displacement into an electrical signal, the fuel injection amount is determined according to the detected output of this air flow meter. 1ilJ
IIl.

Problems to be Solved by the Invention] However, the above-mentioned fuel injection amount control device is still not sufficient and has the following problems.

In other words, when calculating the fuel injection amount required by the internal combustion engine, the intake air amount of the internal combustion engine, which is a parameter, is estimated from the output of the air flow meter. This causes an overshoot in the output. The throttle valve of an internal combustion engine is suddenly opened,
When the output of an internal combustion engine suddenly changes, for example when a shift change is made, the air flow meter displaces in response to the change, but the more rapid this change is, the greater the inertial force of the air flow meter becomes. Overshoot occurs in the output.

Therefore, if the fuel injection amount is simply calculated and executed faithfully to the output of this airflow meter, an overshoot proportional to the above overshoot will occur in the fuel injection amount, and an excess amount of fuel will be supplied. As a result, the air-fuel ratio is temporarily controlled to the rich side, and a rich spike occurs. This means that when a rich spike occurs, sudden acceleration is performed, which not only reduces drivability, but also causes problems such as an increase in HC and CO acid components in the exhaust gas, worsening emissions. Was.

The present invention has been made to solve the above-mentioned problems, and even in a fuel injection amount control device for an internal combustion engine using a moving vane type air flow meter, drivability is improved even if a sudden change occurs in the intake air amount. The object of the present invention is to provide an excellent fuel injection amount control device for an internal combustion engine that can improve emissions.

[Means for solving the problems] In order to solve the above problems, the means constituted by the present invention are as follows:
As shown in the basic configuration diagram in FIG. 1, there is an air flow meter M2 that detects the intake air l of the internal combustion engine M1 using a moving vane method, and fuel that is injected and supplied to the internal combustion engine M1 based on the output of the air flow meter M2. A fuel injection amount control device for an internal combustion engine, comprising: a fuel injection amount determining means M3 for determining an injection amount; a throttle opening detecting means MA for detecting an opening of a throttle valve of the internal combustion engine M1; The upper limit value of the fuel injection amount determined by the fuel injection amount determining means M3 is determined according to the opening degree of the throttle valve determined by the detection means MA, and according to the opening degree of the first throttle valve. With respect to the upper limit value of the first fuel injection amount, which is determined by The gist of the present invention is a fuel injection amount control device for an internal combustion engine, which is characterized in that it can be used in conjunction with an upper limit value changing means MB that directly corresponds to the upper limit w1 of the fuel injection amount of No. 2.

[Operation] In the present invention, the throttle opening detection means MA detects the opening of the throttle valve for controlling the intake air amount of the internal combustion engine M1. In terms of detection accuracy, is the opening degree greater than the predetermined value?
It is a digital type that detects whether the predetermined value is small, and the predetermined value is one or more, or it is an analog type that shows a linear output according to the opening degree of the throttle valve. It's okay. Therefore, a simple device, such as one that doubles as a throttle opening sensor conventionally attached to a throttle valve, or a so-called power switch that detects whether the throttle opening is greater than a predetermined opening It consists of things that are done.

Further, the upper limit value changing means MB sets a predetermined upper limit value to the fuel injection amount determined by the fuel injection amount determining means M3 according to the output of the throttle opening detection means MA.

That is, the fuel injection amount determining means M3 estimates the required fuel m of the internal combustion engine 111 [M1 based on the output of the air flow meter M2 that detects the intake air amount of the internal combustion engine M1, and determines the fuel injection amount. By setting a predetermined upper limit value on the fuel injection amount determined by the fuel injection source determining means M3, fuel injection exceeding the upper limit value is prevented from being executed. The predetermined upper limit value here is determined in accordance with the detection result of the throttle distance detection means MA.

The upper limit value is determined such that the kneading upper limit value is set higher when the opening degree of the throttle valve is large, and conversely, the upper limit value is set lower as the opening degree of the throttle valve is smaller.

EXAMPLES Hereinafter, in order to explain the present invention more specifically, the present invention will be described in detail by giving examples.

[Implementation W4] First, FIG. 2 is an explanatory diagram showing a gasoline engine and its peripheral devices in which the fuel injection amount control device of the embodiment is mounted.

1 is the gasoline engine body, 2 is the piston, 3 is the spark plug, 4 is the exhaust manifold, 5 is the exhaust manifold 4
6 is a fuel injection valve that injects fuel into the intake air of the gasoline engine main body 1, 7 is an intake manifold, and 8 is an oxygen sensor that detects the residual oxygen S level in the exhaust gas. 9 is a water temperature sensor that detects the temperature of the gasoline engine cooling water; 10 is a throttle valve that is linked to an accelerator pedal (not shown) to control the intake air amount of the gasoline engine 1; It is opened and closed. 11 is a throttle l for detecting the open/closed state of the throttle valve 10;
11 [t sensor; 13 is a moving vane for measuring the amount of intake air; the displacement of this moving vane 13 is output from an air flow meter 14; Reference numeral 15 represents a surge tank that absorbs the pulsation of intake air.

16 is an igniter that outputs the high voltage necessary for ignition; 17 is a detripulator that is linked to a crankshaft (not shown) and distributes the high voltage generated by the ianitar 16 to the spark plugs 3 of each cylinder; and 18 is a distributor. 17 is a rotation angle sensor that outputs 24 pulse signals for one revolution of the distributor 17, that is, two revolutions of the crankshaft. 19 is a cylinder that outputs one pulse signal for one revolution of the distributor 17. 20 represents a discrimination sensor, 20 represents an electronic Ill 911 circuit, 21 represents a key switch, and 22 represents a starter motor. 26 represents a vehicle speed sensor that is linked to the axle and transmits a pulse signal according to the vehicle speed.

Next, FIG. 3 shows a block diagram of the electronic control circuit 20 and its related parts.

30 is a central processing unit (hereinafter simply referred to as CPtJ) that inputs and activates the data output from each sensor according to the l11w program and performs processing for controlling the operation of various devices; 31 is a control program and initial data; A read-only memory (hereinafter simply referred to as ROM) is stored, and 32 is a random access memory (hereinafter simply referred to as RA) in which data input to the electronic control circuit 20 and data required for arithmetic control are temporarily read and written.
33 is a backup random access memory (hereinafter simply referred to as backup RAM) which is a non-volatile memory backed up by a battery so as to retain data necessary for subsequent internal combustion operations even when the key switch 21 is turned off. 34 to 37 are buffers for the output signals of each sensor, and 38 is a buffer for the output signal of each sensor.
A multiplexer that selectively outputs to J30, 39 an A/D converter that converts an analog signal into a digital signal, 40
converts each sensor signal to CP via the buffer 7 or via the buffer, multiplexer 38 and A/D converter 39.
Multiplexer 3 from CPU 30 as well as sending to U30
8 represents an input/output port that outputs a control signal for the A/D converter 39.

41 converts the output signal of the oxygen sensor 5 into the comparator 4.
The buffer sent to 2, 43 is the rotation angle sensor 1.

18 and a shaping circuit that shapes the waveforms of the output signals of the cylinder discrimination sensor 19. The other sensor signals are sent to the CPU 30 by the input/output port 46 directly or via the buffer 41 or the like.

Additionally, 47.48 connects to CP via output port 49.50.
The fuel injection valve 6 and the injector 1 are activated by the signal from U30.
6 respectively represent the drive circuits that drive 6. Also 5
1 is a path line for signals and data, 52 H C
PU 30 represents a clock circuit that sends a clock signal serving as a control timing to the ROM 31, RAM 32, etc. at predetermined intervals.

Next, the control program will be explained.

FIG. 4 (A>) and FIG. 5 are flowcharts of this embodiment.

First, the control program shown in FIG. 4(A) will be explained. This guard processing routine is stored in the ROM 31 in advance, and is executed for a predetermined period of time (15m5ec).
) or CP (repeatedly executed at J30) at every predetermined rotation speed.

When the CPU 30 moves to the processing of this routine, step 100 is first executed, and the temperature T of the cold part water temperature is measured from the water temperature sensor 9.
HW is detected, and in the next step 110, the ROM 31 is
The water temperature is compared with the water temperature reference value THB prepared in the internal water temperature.

If THW<THB, the upper limit of fuel injection time is 1 in step 120! The process of this routine is completed by setting TPmax to the value "x1" which is previously prepared in the ROM 31 and TtrN. Further, when TI-IW≧THB, the throttle opening sensor 11
The output TΔ is detected, and the same as the previous water temperature is stored in ROM31.
The magnitude relationship between the throttle opening degree and the reference value TAB stored in the internal memory is determined (step 140), and TAB≧TA
If so, step 120 described above is executed and TAB<
If it is TA, step 150 is executed, Tpmax is set to rX2J (X2<Xl), and this routine ends.

The fuel injection time TP actually executed using Tpmax determined in this way is the fuel injection time T shown in FIG.
Calculated by the P determination routine.

When the CPU 30 enters the processing of this routine, step 200 is executed first, and the rotation angle sensor 18 and J''''j'''7 are
70ゝ-*14(7)lffl"k: M-':f
t+Nr#'/IJ.

The rotational speed NE of the engine 1 and the intake air IQ are calculated and sent to the next step 210.

In step 310, the load Q/NE is calculated from these two basic operation information of the gasoline engine 1, and then the basic fuel injection amount (basic fuel injection time) TP, which is the optimal fuel supply device for the load, is stored in the ROM 31. Calculate using the formula in.

In the following step 220, a correction coefficient K for the basic fuel injection amount TP is calculated based on information from various sensors provided in the gasoline engine system. for example,
The correction coefficient is calculated as a total of various correction values such as the correction coefficient learned from the previous operating state of the gasoline engine 1 and the air-fuel ratio feedback correction coefficient based on the output of the oxygen sensor 5.

Then, in the next step 230, the correction coefficient K obtained as described above is used to calculate the fuel injection amount (fuel injection time) TP to be actually executed using the following formula.

TP4-TPXK In the following step 240, the fuel injection time TP thus obtained is compared in magnitude with the upper limit value TPn+ax of the fuel injection time TP obtained in the routine of FIG. 4(A) described above. If T P < T P rnax, proceed directly to step 260; if TP≧TPWaX, proceed to -H step 250 to convert TP to 71) rRax
After changing to the same value as , step 260 is similarly executed.

In step 240, the thus determined fuel injection time is stored in the TPeRAM 32, and the processing of this routine is ended.

In this way, another fuel injection execution routine reads out the fuel injection time TP stored in the RAM 32 as appropriate, and injects fuel for a time corresponding to the fuel injection time TP to the Ganlin engine 1 from the fuel injection valve 6. By executing this, the gasoline engine 1 can be operated at a desired air-fuel ratio.

FIG. 4 shows the relationship between the throttle opening TA controlled according to the program described above, its reference value TAB, the fuel injection time upper limit 7pmax values X1 and X2, and the fuel injection time TP. (B).

As shown, the throttle opening TA is FJAll! I
When the fuel injection time TP is changed in accordance with the operation of the accelerator pedal, the calculation result of the fuel injection time TP determined by the fuel injection time TP determination routine shown in FIG. 5 shows three sharp peaks as shown in the figure.

However, when the throttle opening degree TA is less than the reference value TAB, the upper limit till(TP w
ax is set to "x2" and no further fuel injection is performed.

In addition, when the throttle opening degree TA exceeds the reference value TAB, a value "×1" larger than the above-mentioned upper limit "×2" is set.
Similarly, the upper limit value of the fuel injection time TP is determined by υ1.

As shown in FIG. 4(B), the fuel injection amount control device of this embodiment, which is controlled in this manner, controls the air flow meter 14 when the throttle opening TA changes from the fully open state to the accelerated state. The upper limit [X
It can be held at 2J, and the throttle opening TA
When TAB becomes larger than the reference value TAB, the upper limit value of the fuel injection time TP is set to a value of "x1", which is larger than the above-mentioned "x2".

Therefore, rich spikes that occur when the throttle opening is relatively small, such as during a normal shift change or starting, are regulated by a smaller upper limit (X2), which limits wasteful fuel injection and reduces the amount of fuel in the exhaust gas. It is also possible to reduce HC and Go.

Moreover, when the throttle opening is large, the upper limit value of the fuel injection time is changed to a large value (Xl), so the acceleration characteristics that follow the throttle opening are not impaired (good drivability can be obtained). .

Further, in this embodiment, in step 100, it is detected when the gasoline engine 1 is started in cold weather, and when it is cold, a large value "×" is set as the upper limit value of the fuel injection time.
1" is the device to be selected preferentially. This allows the amount of fuel to be increased during startup.

In this way, it will be more effective if the control of this embodiment is executed while taking into account other controls of the gasoline engine 1.

In addition, in this embodiment, the reference value TAB of the throttle opening degree TA is
Although we have described a simple device that sets only one value for It may also be linear and more finely controlled.

[Effects of the Invention 1] As described above in detail with reference to the embodiments, the present invention provides an air flow meter that detects the intake air amount of an internal combustion engine using a moving vane method, and an air flow meter that detects the intake air amount of an internal combustion engine by using a moving vane method. A fuel injection fMII control device for an internal combustion engine, comprising: a fuel injection amount determining means for determining an amount of fuel to be injected; a throttle opening detecting means for detecting an opening of a throttle valve of the internal combustion engine; determining an upper limit value of the fuel injection amount determined by the fuel injection amount determining means in accordance with the opening degree of the throttle valve determined by the detection means; With respect to the upper limit value of the first fuel injection amount, if the opening degree of the second throttle valve is smaller than the opening degree of the first throttle valve, the second fuel injection amount is smaller than the upper limit value of the first fuel injection amount. Fountain II
The present invention is characterized by comprising upper limit value changing means that corresponds to the upper limit value of ffi.

Therefore, even if the air flow meter overshoots due to its inertia and as a result the fuel injection amount to the internal combustion engine attempts to increase excessively, this can be reliably prevented by the guarding process using the upper limit value of the fuel injection amount. Moreover, since the upper limit value is changed as appropriate depending on the throttle opening, the amount of fuel injection can be further suppressed during shift changes and startups, thereby reducing emissions, especially HCl.
Excellent fuel injection quantity control IA for internal combustion engines that can reduce Co and improve fuel efficiency, while also providing good drivability with sufficient fuel supply when the throttle opening is large. They yelled.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is a schematic diagram of a gasoline engine system according to an embodiment, Fig. 3 is a block diagram of its control system, Fig. 4 (A> is a flow chart of its control program, Fig. 4(B) is an explanatory diagram of the control, and Fig. 5 is a flowchart of the control program.Ml...Internal combustion engine M2...Air flow meter M3...Fuel injection amount determining means MA... Throttle opening detection means MB... Upper limit value changing means 1... Gasoline engine 6... Fuel injection valve 9... Water temperature sensor 11... Throttle opening sensor 14... Air flow meter 20... Electronic series controller

Claims (1)

[Scope of Claims] An air flow meter that detects the intake air amount of an internal combustion engine using a moving vane method; and a fuel injection amount determining means that determines the amount of fuel to be injected and supplied to the internal combustion engine based on the output of the air flow meter. A fuel injection amount control device for an internal combustion engine, comprising: a throttle opening detection means for detecting an opening of a throttle valve of the internal combustion engine; and a magnitude of the opening of the throttle valve determined by the throttle opening detection means. The upper limit value of the fuel injection amount determined by the fuel injection amount determining means is determined according to the first upper limit value of the first fuel injection amount determined according to the opening degree of the first throttle valve. upper limit changing means for making the opening of the second throttle valve smaller than the opening of the first throttle valve correspond to a second upper limit of the fuel injection amount smaller than the upper limit of the first fuel injection amount. A fuel injection amount control device for an internal combustion engine, characterized in that: