JPH04112937A - Fuel control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent engine stop or the like by obtaining the supply fuel data at the time of deceleration based on the change of load in the decreasing direction when the load of an engine has suddenly decreased, and by decreasing the supply fuel quantity on the basis of this data, and also by restricting the decreasing action in an operating region less than a prescribed load region. CONSTITUTION:In a fuel control device in which a solenoid valve 8 being provided to each cylinder is controlled by an ECU 23, a basic-driving-time determining means 35 for determining a basic driving time TB for the solenoid valve 8 is provided to the ECU 23. And also an air-fuel ratio correction factor setting means 36 for setting an air-fuel ratio correction factor KAF in correspondence to the operating condition of an engine; correction means 40 to 42 for setting respective correction factors in correspondence to the engine cooling-water temperature, intake-air temperature, and the atmospheric pressure; an acceleration increment correction means 43 for setting an acceleration increment correction time TACL; a deceleration decrement correction means 45 for setting a deceleration decrement correction time TDCL; or the like are provided. And by the action of the deceleration decrement correction means 45, supply fuel quantity is decreased on the basis of the supply fuel data at the time of deceleration that has been obtained on the basis of the change of load in the decreasing direction, and in the operating region less than a prescribed load region, the decreasing action is restricted.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an internal combustion engine (hereinafter referred to as "engine" as necessary) that controls the amount of fuel supplied to the internal combustion engine according to the operating state of the engine. It relates to an engine fuel control device.

[Prior Art] Many so-called electronic fuel control devices have been proposed that control the amount of fuel supplied to the intake system of an engine according to the operating state of the engine. Prevents the air-fuel ratio from becoming overrich due to fuel adhering to the intake port or intake manifold flowing into the combustion chamber when decelerating by stopping pressing the accelerator pedal after high-load operation or acceleration. Therefore, when the engine load suddenly decreases as described above, it is possible to obtain fuel supply data during deceleration based on the change in the load decreasing direction and reduce the amount of supplied fuel based on this data on the fuel supply during deceleration. It is being done.

[Problem to be Solved by the Invention] By the way, if such fuel supply reduction control during deceleration is performed over the entire load range, there is a risk that the engine will stop in the operating range below a predetermined load range, for example in the low load and low rotation range. There are also problems with drivability in low load and high rotation ranges.

The present invention was devised in view of the above-mentioned problems, and is an internal combustion engine that prevents the engine from stopping or deteriorating drivability by appropriately setting the operating range in which the amount of fuel supplied during deceleration is reduced. The purpose of the present invention is to provide a fuel control device.

[Means for Solving the Problem] Therefore, the fuel control device for an internal combustion engine of the present invention is a fuel control device for an internal combustion engine that controls the amount of fuel supplied to the internal combustion engine according to the operating state of the internal combustion engine. , a deceleration supply fuel reduction means is provided which calculates deceleration supply fuel data based on a change in the load in a decreasing direction when the load of the internal combustion engine suddenly decreases, and reduces the supply fuel amount based on the deceleration supply fuel data. According to a first aspect of the present invention, the operation of the deceleration fuel supply reducing means is restricted in an operating range below a predetermined load range.

Furthermore, if the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value, the supplied fuel data during deceleration is sequentially updated to reduce the supplied fuel amount, while the load is decreased in the decreasing direction. When the magnitude of the rate of change becomes smaller than the first judgment value, the supplied fuel during deceleration is multiplied by a coefficient smaller than 1 to gradually decrease the supplied fuel amount during deceleration. Can constitute a weight loss means (Claim 2)
.

Furthermore, when the operating range is below the predetermined load range in which the operation of the fuel supply reduction means during deceleration is to be restricted, the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value. Even if the deceleration fuel supply data is multiplied by a coefficient smaller than 1 at that time, the supplied fuel amount can be configured to gradually reduce the supplied fuel amount (Claim 3). .

Further, if the magnitude of the rate of change in the throttle opening in the decreasing direction is equal to or greater than the second judgment value, a correction means may be provided to further increase the degree of reduction in the amount of supplied fuel by the supplied fuel amount reduction means during deceleration. It is possible (Claim 4).

In this case, a load detection means periodically samples operating parameters corresponding to the load of the internal combustion engine, and a weighting coefficient is added to the latest output of this load detection means and the previous load data for fuel calculation to obtain the latest fuel. A fuel calculation load data setting means for repeatedly obtaining calculation load data, and basic data for setting the amount of fuel to be supplied to the internal combustion engine based on the latest fuel calculation load data from the fuel calculation load data setting means. basic data calculating means for calculating the fuel supplied during deceleration, and the means for reducing the supplied fuel during deceleration is configured to calculate the supplied fuel data during deceleration based on the output of the load data setting means for fuel calculation changing in the direction of load reduction. and a second data setting means for obtaining data for changing the amount of fuel to be supplied based on the output of the first data setting means, and the correction means so that when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value, the degree of weight given to the latest fuel calculation load data of the latest output of the load detection means increases. It may be configured as a means for changing the weighting coefficient (claim 5), and further, the correction means may be configured to change the weighting coefficient when the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second judgment value. The correction value may be configured as a means for subtracting a correction value from the latest output of the load detection means (claim 6), and the correction means may be configured as a means for subtracting a correction value from the latest output of the load detection means. In this case, means for subtracting a correction value from the latest output of the load detecting means and changing the weighting coefficient to increase the degree of weight given to the latest fuel calculation load data of the latest output of the load detecting means. (Claim 7).

[Function] In the above-described fuel control device for an internal combustion engine of the present invention, when the load of the internal combustion engine suddenly decreases, the supplied fuel during deceleration data is adjusted based on the change in the load decreasing direction by the action of the deceleration supplied fuel reducing means. is determined, and the amount of supplied fuel is reduced based on this supplied fuel data during deceleration, but in an operating range below a predetermined load range, the operation of the means for reducing supplied fuel during deceleration is restricted (Claim 1) .

In addition, if the magnitude of the rate of change in the direction of load reduction is greater than or equal to the first judgment value, the supplied fuel data during deceleration is sequentially updated to reduce the amount of supplied fuel, while the rate of change in the direction of load decrease is When the magnitude becomes smaller than the first judgment value, the amount of supplied fuel is gradually decreased by multiplying the supplied fuel data during deceleration by a coefficient smaller than 1 (Claim 2).
).

Furthermore, when the operating range is below the predetermined load range in which the operation of the fuel supply reduction means during deceleration is to be restricted, the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value. However, the amount of fuel supplied during deceleration is gradually decreased by multiplying the supplied fuel data during deceleration by a coefficient smaller than 1 (Claim 3).

Further, when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value, the correction means may further increase the degree of reduction in the amount of supplied fuel by the M fuel supply reduction means during deceleration. It is possible (Claim 4).

In this case, when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value, the degree of weight given to the latest fuel calculation load data of the latest output of the load detection means is increased. changing the weighting coefficient (claim 5);
The magnitude of the rate of change in the throttle opening in the decreasing direction is the second
When it is equal to or greater than the second determination value, the correction value is subtracted from the latest output of the load detection means (claim 6), or when the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second determination value, In addition to subtracting the correction value from the latest output of the load detection means,
The weighting coefficient may be changed to increase the degree of weight given to the latest fuel calculation load data of the latest output of the load detection means (Claim 7).

[Embodiment] Hereinafter, a fuel control system for an internal combustion engine as an embodiment of the present invention will be explained with reference to the drawings. FIG. 1(a) is a block diagram showing the fuel supply control system, and FIG. 1(b) is a block diagram showing the fuel supply control system. A block diagram mainly showing the hardware, Figure 1 (c
) is a block diagram for the A/N calculation, Figure 1(d)
is a block diagram showing the deceleration reduction correction means, and FIG.
) is a block diagram showing another example of the deceleration reduction correction means,
Figure 2 is an overall configuration diagram showing the engine system, Figure 3
, 4 are flowcharts for explaining the control procedure, FIG. 5(a) is a diagram for explaining the control zone of the acceleration increase correction means, and FIG. 5(b) is a diagram for explaining the deceleration reduction correction means. Fig. 6 is a diagram showing its tailing coefficient characteristics, Fig. 7 is a change characteristic diagram to explain its action, and Figs. 8 to 15 all explain its control procedure. FIG. 16 is a correction value characteristic diagram, and FIG. 17 is a change characteristic diagram for explaining the effect.

Now, the engine system controlled by this device is
As shown in Fig. 2, an engine (internal combustion engine) E has an intake passage 2 and an exhaust passage 3 that communicate with its combustion chamber 1, and the intake passage 2 and the combustion chamber 1 are different from each other. Communication is controlled by the intake valve 4, and the exhaust passage 3
The communication between the combustion chamber 1 and the combustion chamber 1 is controlled by an exhaust valve 5.

In addition, an air cleaner 6 is installed in the intake passage 2 in order from the upstream side.
, a throttle valve 7, and an electromagnetic fuel injection valve 8 (hereinafter sometimes referred to as an electromagnetic valve 8 or an injector 8).In the exhaust passage 3, a catalyst for purifying exhaust gas is sequentially installed from the upstream side. A converter (three-way catalyst) 9 and a muffler (silencer) (not shown) are provided. −
Note that the intake passage 2 is provided with a surge tank 2a.

Further, solenoid valves 8 are provided in the intake manifold portion for the same number of cylinders. Now, assuming that the engine E of this embodiment is an in-line four-cylinder engine, four electromagnetic valves 8 are provided. That is, so-called multi-point fuel injection (
It can be said that it is an engine based on the MPI method.

Further, the throttle valve 7 is connected to the accelerator pedal via a wire cable, so that the opening degree changes depending on the amount of depression of the accelerator pedal.
Furthermore, it is also driven to open and close by an idle speed control motor (ISC motor) 10, so that the opening degree of the throttle valve 7 can be changed during idling without stepping on the accelerator pedal. It has become.

With such a configuration, the air taken in through the air cleaner 6 according to the opening degree of the throttle valve 7 is mixed with the fuel from the solenoid valve 8 in the intake manifold part to an appropriate air-fuel ratio, and the air is mixed with the fuel from the solenoid valve 8 in the combustion chamber. By igniting the spark plug at an appropriate timing, the mixture is combusted and generates engine torque, and then is discharged into the exhaust passage 3 as exhaust gas, and the catalytic converter 9 converts C○ in the exhaust gas. After the three harmful components of + HC + N Ox are purified, the sound is muffled by a muffler and released into the atmosphere.

Furthermore, in order to control this engine E, various sensors are provided. First, on the intake passage 2 side, an air flow sensor 11 that detects the intake air amount from Karman vortex information, an intake air temperature sensor 12 that detects the intake air temperature, and an atmospheric pressure sensor 13 that detects the atmospheric pressure are installed in the air cleaner installation part. A potentiometer-type throttle sensor 14 is provided at the throttle valve installation portion to detect the opening degree of the throttle valve 7 (throttle opening degree). Idle switch 15 and ISC that detect idling state
Motor position sensor 1 that detects the position of motor 10
6 is provided.

In addition, on the exhaust passage 3 side, an upstream portion of the catalytic converter 9 detects the oxygen concentration (02 concentration) in the exhaust gas, and the output value changes rapidly near a predetermined air-fuel ratio (stoichiometric air-fuel ratio). λ type oxygen concentration sensor 17 (hereinafter simply referred to as 0□ sensor 17
) has been established.

Furthermore, as other sensors, a water temperature sensor 19 that detects the engine cooling water temperature and a crank angle sensor 21 that detects the crank angle (this crank angle sensor 21 also serves as an engine rotation speed sensor that detects the engine rotation speed)
and TDC to detect the top dead center of the first cylinder (reference cylinder)
A sensor 22 is provided at each distributor.

Detection signals from these sensors are input to an electronic control unit (ECU) 23.

Note that a voltage signal from the battery sensor 2S that detects the voltage of the battery 24 and a signal from the ignition switch (key switch) 26 are also input to the ECU 23.

In addition, the hardware configuration of the ECU 23 is as shown in Fig. 1(b), but this ECU 23 has a CP as its main part.
It is equipped with U2'7, and to this CPU27,
Intake temperature sensor 12. Atmospheric pressure sensor 13, throttle sensor 14, 02 sensor 17. Detection signals from the water temperature sensor 19 and battery sensor 25 are input to the interface 28.
and A/D converter 30, detection signals from idle switch 15 and ignition switch 26 are input via input interface 29, and air flow sensor 11. Detection signals from the crank angle sensor 21 and TDC sensor 22 are directly input to the input port.

Furthermore, the CPU 27 connects the ROM 31. Data is exchanged between the RAM 32, which is updated and sequentially rewritten, and the battery backup RAM (BURAM) 33, which retains its memory contents while the battery 24 is connected. It has become.

In addition, the data in RAM32 is stored in the ignition switch 2.
When 6 is turned off, it disappears and is reset.

Now, if we focus on fuel injection control (air-fuel ratio control), the CPU
From 27, a fuel injection control signal calculated by a method described later is outputted via an injector driver 34, and for example, four electromagnetic valves 8 are sequentially driven.

A functional block diagram for such fuel injection control (electromagnetic valve driving time control) is shown in FIG. 1(a). That is, when looking at this ECU 23 from a software perspective, this ECU 23 first has a basic drive time determining means 35 that determines the basic active time TB for the solenoid valve 8, and this basic drive time determining means 35 has an air flow sensor. Intake air amount A information from 11 and crank angle sensor 21
The basic immediate action time TB is determined based on intake air amount information per engine rotation (hereinafter sometimes referred to as Alx) obtained from the engine rotation speed N information from the engine rotation speed N information.

By the way, the above Alx has the A/N shown in FIG. 1(C).
It is determined by the calculation unit 46. This A/N calculation section 46 is
A load detection means that regularly samples operating parameters (intake air amount information per engine rotation) corresponding to the load of the engine E, and the latest output of this load detection means (
The latest fuel calculation load data A/N (n )
It has various functions including a load data setting means for fuel calculation that repeatedly obtains the following values.

Alx(n)4-Alx(n-1)+(1-K)・Al
x(s)” (1) where K is the filter gain,
This filter gain is supplied from a filter gain setting section 47.

In this embodiment, when the magnitude of the rate of change in the throttle opening in the decreasing direction is greater than or equal to a certain judgment value (referred to as a second judgment value), the filter gain setting unit 47 determines the latest The filter gain K can be changed so that the degree of weight given to the latest fuel calculation load data A/N (n) of the output A/N (s) is increased. For example, the value of K during normal operation is 0.
．． If it is about 9, when the rate of change in the throttle opening in the decreasing direction exceeds a certain judgment value (second judgment value), K is changed to, for example, 0.3.

Here, a flowchart for changing the filter gain is shown in FIG. 9. That is, first,
After initialization in step D1, step D2
Then, it is determined whether the rate of change in the throttle opening in the decreasing direction is greater than or equal to the second judgment value [N, if blockade expression is not used, it is determined whether the throttle opening change ΔTh≦(-dead band) , if not, in step D4,
The usual value KF is chosen as the filter gain, but
When the magnitude of the rate of change in the decreasing direction of the throttle opening becomes equal to or greater than the second determination value, in step D3, the value KDCL during deceleration is selected as the filter gain.

In addition, assuming that ni'=1-, Alx(n):(1-')・Alx(n-1)+'
・If expressed as “Alx(s)” (2), it is 1. For example, the value of ’ during normal operation is about 0.1, and the magnitude of the rate of change in the decreasing direction of the throttle opening is the second judgment value. In the above case, it goes without saying that, for example, '' is changed to 0.7, and the flowchart for changing this coefficient ' is also the same as that shown in FIG.

Based on the latest fuel calculation load data A/N (n) from the fuel calculation load data setting means obtained in this way, the basic recording time determining means 35 serving as the basic data calculation means determines whether the engine E A basic immediate action time TB is determined as basic data for setting the amount of fuel to be supplied to the engine.

Further, the A/N calculation section 46 is provided with a correction value setting section 48, as shown in FIG. When the magnitude of the rate of change is greater than or equal to the second judgment value, the correction value ΔA/N (Th) is calculated from the latest output A/N (s) of the load detection means.
This is to subtract .

That is, the correction value ΔA/N (
The latest output A/N' (s) corrected by Th) is A(s) = A/N(s) - ΔA/N(Th)
-(3), and the latest fuel calculation load data A/N (n) is A/N(n) = -A/N(n-1)+(1-K)・A
/N'(s)''(4) or A/N(n)=(1-ni')・A/N(n-1)+ni'・A/N'(s)...(5) Become.

The relationship between the correction value ΔA/N (Th) and the throttle opening change ΔTh can be expressed, for example, in the following table or in the flowchart for determining the correction value ΔA/N (Th) in section E. It will look like Figure 11. That is, first,
After initialization in step F1, step F2
Then, it is determined whether the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second judgment value, and if not, a correction value ΔA/N (Th) is determined in step F4.
, O is selected, but if the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value [If absolute value expression is not used, ΔTh≦(−dead band)], then correction is performed in step F3. A value ΔA/N (Th) is calculated.

Of course, the filter gain setting section 47 and the correction value setting section 4
8, when the magnitude of the rate of change in the throttle opening in the decreasing direction is greater than or equal to the second judgment value, a correction value ΔA/N ( Th)
and filter gain K (or '
) to obtain the latest output A/N'(s) of the load detection means.
The degree of weight given to the latest fuel calculation load data A/N (n) may be increased.

A flowchart in this case is shown in FIG. 13. That is, first, after initialization in step H1, in step H2, the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value [if absolute value expression is not used, 2ΔTh≦(-dead zone)]. If not, a normal value KF is selected as the filter gain in step H5, and a correction value ΔA/N (Th) is selected in step H6.
However, when the rate of change in the throttle opening in the decreasing direction exceeds the second judgment value, step H is selected.
3, set the filter gain to the value during deceleration K DCL
is selected, and in step H4, the correction value ΔA/N
(Th) is calculated.

Furthermore, as shown in FIG.
Air-fuel ratio correction coefficient setting means 36 for setting AF. A cooling water temperature correction means 40 that sets a correction coefficient KWT according to the engine cooling water temperature detected by the water temperature sensor 19. Intake temperature correction means 41 for setting a correction coefficient KAT according to the intake air temperature detected by the intake air temperature sensor 12. Atmospheric pressure correction means 42 that sets a correction coefficient KAP according to the atmospheric pressure detected by the atmospheric pressure sensor 13. Acceleration increase correction means 43 for setting acceleration increase correction time T ACL. Deceleration reduction correction means 45, which constitutes a deceleration fuel supply reduction means for setting the deceleration reduction correction time TDCL. A dead time correction means 44 is provided for setting a dead time (invalid time) TD in order to correct the opening time according to the battery voltage detected by the battery sensor 25.

Then, the required immediate action time Tinj [=TR×KWTx
KATX KAPXKAF+TACL TDCL+”
r.

The solenoid valve 8 is driven by = TBXK + TACL TDCL + TD.

That is, when driving this electromagnetic valve 8, for example, if the latest fuel calculation load data A/N (n) is not corrected using the filter gain and correction value, as shown in FIG. 4 After the fire control (step AI), the basic active time TB is found (step A2), and the immediate action time T inj is found from this basic active time TB and other coefficients and times (step A3). , solenoid valve 8
is driven to inject a desired amount of fuel (step A4).

In addition, if only the filter gain is corrected when obtaining the latest fuel calculation load data A/N(n), the 8th
As shown in the figure, after ignition control (step C1),
After correcting the filter gain and finding the latest fuel calculation load data A/N(n) (step C2), the basic drive time TB is found (step C3), and this basic drive time T
After determining the drive time Tinj from B, other coefficients, and time (step C4), the solenoid valve 8 is driven to inject a desired amount of fuel (step C5).
.

Furthermore, if only the correction value △A/N (Th) is corrected when obtaining the latest fuel calculation load data A/N (n), the ignition control (step El) can be adjusted as shown in Fig. 10. Later, in step E2, the latest output A/N (s) of the load detection means is corrected by the correction value ΔA/N (Th), and this corrected latest output A/N' of the load detection means is obtained.
(s) using the latest fuel calculation load data A/N (
n) (step E3), the basic active time TB
(Step E4), and after determining the driving time T inj from this basic driving time TB and other coefficients and times (Step E5), the solenoid valve 8 is driven to inject the desired amount of fuel. is carried out (step E6).

Furthermore, the latest fuel calculation load data A/N (n
), if both the filter gain and the correction value are corrected when determining the current output A/N (s ) is corrected by the correction value ΔA/N (Th) to obtain the latest output A/N of the corrected load detection means.
After calculating the latest fuel calculation load data A/N(n) by using N' (S) and correcting the filter gain,
Step G3) and find the basic driving time TB (Step G3).
4) After calculating the driving time T inj from this basic driving time T8 and other coefficients and times (Step G5)
, the electromagnetic valve 8 is moved once to inject a desired amount of fuel (step G6).

Therefore, the filter gain setting section 47 and the correction value setting section 48 further increase the reduction dust of the supplied fuel amount when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value. A correction means is configured to

By the way, as shown in FIG. 1(d), the deceleration reduction correction means 45 includes a ΔA/N calculating section 451. Switching unit 452. Switching control unit 453. Tailing processing section 454. It is configured to have the functions of the TDCL calculation section 455.

Here, the ΔA/N calculation unit 451 functions as a first data setting unit that calculates the supply fuel data ΔA/N during deceleration based on the fact that the output of the fuel calculation load data setting unit changes in the direction of load reduction. In this ΔA/N calculation unit 451, the latest fuel calculation load data A/N(n)
The fuel supply data ΔA/N during deceleration is calculated by subtracting the previous fuel calculation load data A/N(n-1) from the previous fuel calculation load data A/N(n-1). That is, ΔA/N=A/N(n)-A/N(n-1)
” (6).

The switching unit 452 selects whether the deceleration supply fuel data ΔA/N from the ΔA/N calculation unit 451 is supplied directly to the TDCL calculation unit 455 or via the tailing processing unit 454.

The switching control unit 453 performs switching control of the switching unit 452, and when the magnitude of the rate of change in the direction of decrease in load is equal to or greater than a certain judgment value (first judgment value) [#4A When not using the versus value expression, When ΔA/N≦(-dead zone) or an operating range below a predetermined load range, for example, the volumetric efficiency Ev is 20%, for example.
In the following operating region [see the unhatched region in Fig. 5(b)], the supplied fuel data during deceleration ΔA/
N is supplied via the TDCL calculation unit 455 and the tailing processing unit 454, and otherwise the supplied fuel data Δ during deceleration is
Control is performed such that A/N is directly supplied to the TDCL calculation section 455.

The tailing processing unit 454 stores fuel supplied during deceleration data ΔA.
/N is multiplied by a tailing coefficient KT (WT) smaller than 1 to gradually reduce the amount of fuel supplied. Note that this tailing coefficient KT (WT) depends on the engine coolant temperature WT, and an example of its characteristics is shown in FIG.

Based on the output ΔA/N of the ΔA/N calculation unit 451 as the first data setting means, the T DCL calculation unit 455 calculates
This constitutes a second data setting means for determining the deceleration reduction correction time T DCL as data for changing the amount of supplied fuel in the direction of decreasing it. Specifically, the supplied fuel data during deceleration ΔA/N [= D (A/N)] and is multiplied by the injector gain, pulse constant, etc. to obtain the deceleration reduction correction time TDCL.

In this way, the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value [If absolute value expression is not used, ΔA/N≦
(-dead zone) In the case of ko, the supplied fuel data during deceleration ΔA/
While updating N sequentially to reduce the amount of supplied fuel, the magnitude of the rate of change in the direction of decreasing load is smaller than the first judgment value [If absolute value expression is not used, ΔA/N> (-dead zone) ], the supplied fuel data during deceleration at that time ΔA/
The amount of fuel supplied is gradually reduced by multiplying N by the tailing coefficient KT (WT).

This is shown in a flowchart as shown in FIG.

That is, after initializing in step B1, after calculating the fuel correction coefficient (water temperature, intake temperature, etc.) (step B2), if the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value [absolute value If not expressed, ΔA/N≦(−
dead zone)], take the YES route in step B3, and in step B4, set 1ΔA/N l to D (A/N
), and the deceleration reduction correction time T DCL is determined using this D (A/N) (step B5).

If ΔA/N> (-dead zone) and ΔA/N<(10 dead zone), tailing processing is performed in step B7, and then processing in step B5 (deceleration reduction correction time T
Processing to obtain DCL) is performed.

In addition, when ΔA/N≧(+dead zone) (when accelerating)
Then, 1ΔA/Nl is set as D (A/N) (step B8), and this D (A/N) is used to calculate the acceleration increase correction time T ACL (step B
9).

Furthermore, in an operating region below a predetermined load region (an operating region in which the volumetric efficiency Ev is, for example, 20% or less), even if the magnitude of the rate of change in the direction of load reduction is greater than or equal to the first judgment value, The amount of supplied fuel is gradually decreased by multiplying the supplied fuel data ΔA/N during deceleration by the tailing coefficient KT (WT) at that time. As a result, the operation of the deceleration reduction correction means 45 is restricted in an operating range below a predetermined load range.

Note that when the operating range is below a predetermined load range (an operating range where the volumetric efficiency Ev is, for example, 20% or lower).

The operation of the deceleration reduction correction means 45 may be prohibited even if the magnitude of the rate of change in the load reduction direction is greater than or equal to the first judgment value.

In this way, from the high load region when the throttle is fully opened to the predetermined low load region (operating region with volumetric efficiency Ev of 20%) [see the hatched part in FIG. Since this is set as a control zone, when deceleration is performed after high-load operation or after acceleration, fuel reduction control works appropriately immediately after deceleration, making it possible to realize control without deceleration shock.

In addition, the operating range below the predetermined low load range [Fig. 5(b)
(see the unhatched portion), the operation of the deceleration reduction correction means 45 is restricted (including prohibited), so that the engine does not stop or the drivability deteriorates due to the fuel reduction.

Further, when the magnitude of the rate of change in the load decreasing direction becomes smaller than the first judgment value, or when the deceleration reduction correction means 4
When the operating range falls below a predetermined load range in which the operation of 5 is to be restricted, so-called tailing processing is performed in which the supplied fuel amount during deceleration is multiplied by a tailing coefficient smaller than 1 to gradually reduce the supplied fuel amount. Therefore, transient processing can be performed smoothly.

Furthermore, when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value, the reduction dust of the supplied fuel amount is further increased, so that the injection amount immediately after the throttle is returned is reduced. It can be quickly reduced, and this can greatly contribute to improving fuel efficiency and exhaust gas performance.

Note that if the rate of change in the throttle opening in the decreasing direction is greater than or equal to the second judgment value [if absolute value expression is not used, Δ
In the case of Th≦(-dead zone), if the throttle opening is greater than a certain opening, the time T DCL (ΔT
h) may be subtracted to further increase the reduction in the amount of fuel supplied.

In this case, as shown in FIG. 1(e), a T DCL (ΔTh) calculation unit 456 is added to the deceleration reduction correction means 45. Here, the −TDCL(ΔTh) calculation unit 456 is
The magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value [If absolute value expression is not used, if ΔTh≦(-dead band), then the time corresponding to the throttle opening change ΔTh This is to find T DCL (ΔTh), and the time T DC+, (Δ
Th) is obtained by multiplying the base value obtained from the map by the sum of the water temperature correction value and the engine rotation speed correction value. Note that the base value and water temperature correction value obtained from the map are the same data as for asynchronous injection.

Further, this time TDCL (ΔTh) is set so that the integrated value within a predetermined time does not exceed an upper limit value.

Here, a flowchart for calculating the time T DCL (ΔTh) is shown in FIG. 15. In this FIG. 2 judgment value or more [#@
If the comparison table is not expressed, if ΔTb≦(-dead band), take the YES route in step J2, and if the throttle opening is greater than a certain opening (TPS (V) > lower limit TP
S (V)), take the YES route in step J3 and cumulatively add the absolute value of the throttle opening change ΔTh (step J4). (or changes depending on the engine speed) (step J5), and as long as the upper limit is not exceeded, a map value corresponding to the cumulative ΔTh is read out (step J6), and this map value is applied with water temperature and engine speed correction (Ne correction). ), the time TDcL(ΔTh
) is determined (step J7).

Also, step J2. J3. In the case of No in J5, the time T DCL (ΔTh) is set to O (step J9
).

Note that step J8 means that the T DCL calculating section 455 calculates the deceleration reduction correction time T DCL.

In this case, when driving the solenoid valve 8, the 14th
As shown in the figure, after ignition control (step II),
Determine the basic driving time TB (step E 2), and calculate the basic driving time TB and other coefficients and times [the above time T DC
After determining the jump time Tinj from [L (including ΔTh)] (step 3), the solenoid valve 8 is driven to inject a desired amount of fuel (step I4).
.

Even in this case, since the injection amount can be quickly reduced immediately after the throttle is returned, it can contribute to improving fuel efficiency and exhaust gas performance.

The acceleration increase correction means 43 sets the acceleration increase correction time T ACL asynchronously with the injection timing.
The control zone is an operation region where the volumetric efficiency Ev is, for example, 70% or less [see the hatched part in FIG. 5(a)].

By the way, the correction time T for deceleration reduction is based on ΔA/N.
Throttle opening, fuel injection amount, and A/N when only the DCL setting correction (this correction is referred to as ΔA/N correction) and when this ΔA/N correction is not performed.
The change characteristics with respect to N and ΔA/N [D (A/N)] are shown in FIGS. 7(a) to 7(d).

Here, when only ΔA/N correction is performed, the characteristic of the present invention in which the fuel is reduced immediately after the throttle is fully opened is shown by the solid line, and when only ΔA/N correction is performed, the volumetric efficiency Ev is 7.
The dotted line indicates the characteristic in which the fuel weight reduction is not performed unless it becomes 0%, and the chain line indicates the characteristic in which the ΔA/N correction is not performed.

Further, in FIG. 7, it can be seen that the tailing process is performed when the operating range is below a predetermined load range (the operating range where the volumetric efficiency is 20% or less).

Further, when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value, a correction is made to further increase the degree of decrease in the amount of supplied fuel (this correction will be referred to as ΔTh correction), ΔA/ Throttle opening when N correction, ΔTh correction and ΔA/N correction are performed, ΔA/N [D (A/N)
The change characteristics of A/N and fuel injection amount are shown below.
The result will be as shown in FIGS. 17(a) to (d).

From this figure, it can be seen that when ΔTh is corrected, ΔA/N appears to immediately respond to a change in the upper throttle opening, and as a result, the fuel injection amount is also quickly reduced immediately after the throttle opening changes. Therefore, it can be seen that by performing the ΔTh correction and the ΔA/N correction, sufficient reduction correction can be made at the beginning of deceleration.

[Effects of the Invention] As detailed above, according to the fuel control device for an internal combustion engine of the present invention, the operation of the supply fuel reduction means during deceleration is restricted in the operating range below a predetermined load range. (Claim 1) When deceleration is performed after high-load operation or after acceleration, fuel reduction control works properly immediately after deceleration.
In addition to realizing control without deceleration shock, there is no engine stoppage or deterioration of drivability due to fuel loss.

Furthermore, when the magnitude of the rate of change in the load decreasing direction becomes smaller than the first judgment value, or when the operating region falls below a predetermined load region in which the operation of the supply fuel reduction means during deceleration is to be restricted, Since the amount of supplied fuel is gradually decreased by multiplying the supplied fuel data during deceleration by a coefficient smaller than 1 (claim 2.3), transient processing can be performed smoothly.

Furthermore, when the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second judgment value, the degree of decrease in the amount of supplied fuel is further increased (claims 4 to 7);
The injection amount can be quickly reduced immediately after the throttle is returned, which has the advantage of greatly contributing to improved fuel efficiency and exhaust gas performance.

[Brief explanation of the drawing]

1 to 17 show a fuel control system for an internal combustion engine as an embodiment of the present invention. FIG. 1(a) is a block diagram showing its fuel supply control system, and FIG. 1(b) is a block diagram thereof. A block diagram mainly showing the hardware, FIG. 1(c) is a block diagram for its A/N calculation, FIG. 1(d) is a block diagram showing its deceleration reduction correction means, and FIG. ) is a block diagram showing another example of the deceleration reduction correction means, FIG. 2 is an overall configuration diagram showing the engine system, FIGS. 3-4 are flow charts for explaining the control procedure, and FIG. (a) is a diagram for explaining the control zone of the acceleration increase correction means, FIG. 5(b) is a diagram for explaining the control zone of the deceleration reduction correction means, and FIG. Figure 7 is a change characteristic diagram to explain its action, Figures 8 to 15 are flowcharts to explain its control procedure, Figure 16 is a correction value characteristic diagram, and Figure 17 is a diagram showing its correction value characteristics. It is a change characteristic diagram for explaining the effect. 1--Combustion chamber, 2--Intake passage, 2a--Surge tank, 3-Exhaust passage, 4--Intake valve, 5-Exhaust valve, 6-
...Air cleaner, 7-Throttle valve, 8-Solenoid valve, 9
- Catalytic converter, 10- ISC motor, 11- Air flow sensor, 12- Intake temperature sensor, 13- Atmospheric pressure sensor, 14- Throttle sensor, 15- Idle switch, 16- Motor position sensor, 17-・
02 sensor, 19--water temperature sensor, 21--crank angle sensor (engine speed sensor), 22-TDC sensor, 23...-electronic control unit (ECU), 24
-Battery, 25-Battery sensor, 26-Igenation switch (key switch), 27-CPU
, 28.29--Human interface, 30-A/D
Converter, 31-ROM, 32-RAM, 33-
Battery backup RAM (BURAM) + 34
- Injector driver, 35-Basic drive time determining means, 36-Air-fuel ratio correction coefficient setting means, 40-Cooling water temperature correction means, 41-Intake temperature correction means, 42-Atmospheric pressure correction means, 43- Acceleration increase correction means, 44-Dead time correction means, 45-Deceleration reduction correction means as supply fuel reduction means during deceleration, 46-4/N calculation section, 47--Filter gain setting section, 48-Correction value setting section, 451-Δ
A/N calculation section, 452--switching section, 453--switching control section, 454--tailing processing section, 455'-'TDCL
Arithmetic unit, 456-TDcL (ΔTh) arithmetic unit, E-engine.

Claims (7)

[Claims] (1) In a fuel control device for an internal combustion engine that controls the amount of fuel supplied to the internal combustion engine according to the operating state of the engine, when the load on the internal combustion engine suddenly decreases, deceleration is performed based on a change in the load in the decreasing direction. Deceleration fuel supply reduction means is provided to obtain supply fuel data during deceleration and reduce the amount of supplied fuel based on the deceleration supply fuel data, and the deceleration supply fuel reduction means comprises:
A fuel control device for an internal combustion engine, characterized in that its operation is restricted in an operating range below a predetermined load range. (2) If the magnitude of the rate of change in the direction of decrease in the load is greater than or equal to the first judgment value, the supplied fuel data during deceleration is sequentially updated to reduce the amount of supplied fuel, while the rate of change in the direction of decrease in the load is When the magnitude of the rate of change becomes smaller than the first judgment value, the data supplied during deceleration is multiplied by a coefficient smaller than 1 to gradually reduce the supplied fuel amount. 2. The fuel control device for an internal combustion engine according to claim 1, further comprising fuel reduction means. (3) When the operating range is below the predetermined load range in which the operation of the fuel supply reduction means during deceleration is to be restricted, the magnitude of the rate of change in the load decreasing direction is greater than or equal to the first judgment value. Even if there is, the fuel supply reduction means during deceleration is configured to gradually reduce the amount of supplied fuel by multiplying the supplied fuel data during deceleration by a coefficient smaller than 1 at that time, A fuel control device for an internal combustion engine according to claim 1 or 2. (4) When the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second judgment value, a correction means is provided for further increasing the degree of reduction in the amount of supplied fuel by the deceleration supplied fuel reducing means. The fuel control device for an internal combustion engine according to claim 1, characterized in that: (5) A load detection means that periodically samples operating parameters corresponding to the load of the internal combustion engine, and a weighting coefficient is added to the latest output of the load detection means and the previous load data for fuel calculation to obtain the latest Fuel calculation load data setting means that repeatedly obtains fuel calculation load data; and basic data for setting the amount of fuel to be supplied to the internal combustion engine from the fuel calculation load data setting means. basic data calculating means for calculating based on the data, and the deceleration supplied fuel reducing means is configured to calculate the decelerating supplied fuel based on the change in the output of the fuel calculation load data setting means in the direction of load reduction. The apparatus includes a first data setting means for obtaining data, and a second data setting means for obtaining data for changing the amount of supplied fuel in a direction based on the output of the first data setting means. , the correction means determines the degree of weight to be given to the latest fuel calculation load data of the latest output of the load detection means when the magnitude of the rate of change in the decreasing direction of the throttle opening is greater than or equal to the second judgment value; 5. The fuel control device for an internal combustion engine according to claim 4, further comprising means for changing the weighting coefficient so that the weighting factor becomes larger. (6) A load detection means that periodically samples operating parameters corresponding to the load of the internal combustion engine, and a weighting coefficient is added to the latest output of the load detection means and the previous load data for fuel calculation to obtain the latest Fuel calculation load data setting means that repeatedly obtains fuel calculation load data; and basic data for setting the amount of fuel to be supplied to the internal combustion engine from the fuel calculation load data setting means. basic data calculating means for calculating based on the data, and the deceleration supplied fuel reducing means is configured to calculate the decelerating supplied fuel based on the change in the output of the fuel calculation load data setting means in the direction of load reduction. The apparatus includes a first data setting means for obtaining data, and a second data setting means for obtaining data for changing the amount of supplied fuel in a direction based on the output of the first data setting means. , the correction means is configured as means for subtracting a correction value from the latest output of the load detection means when the magnitude of the rate of change in the throttle opening in the decreasing direction is larger than the second judgment value; The fuel control device for an internal combustion engine according to claim 4, characterized in that: (7) A load detection means that periodically samples operating parameters corresponding to the load of the internal combustion engine, and a weighting coefficient is added to the latest output of the load detection means and the previous load data for fuel calculation to obtain the latest Fuel calculation load data setting means that repeatedly obtains fuel calculation load data; and basic data for setting the amount of fuel to be supplied to the internal combustion engine from the fuel calculation load data setting means. basic data calculating means for calculating based on the data, and the deceleration supplied fuel reducing means is configured to calculate the decelerating supplied fuel based on the change in the output of the fuel calculation load data setting means in the direction of load reduction. The apparatus includes a first data setting means for obtaining data, and a second data setting means for obtaining data for changing the amount of supplied fuel in a direction based on the output of the first data setting means. , the correction means subtracts the correction value from the latest output of the load detection means and changes the weighting coefficient when the magnitude of the rate of change in the decreasing direction of the throttle opening is equal to or greater than the second judgment value; 5. The fuel control device for an internal combustion engine according to claim 4, further comprising means for increasing the degree of weight given to the latest fuel calculation load data of the latest output of the load detecting means.