JPS6217334A - Fuel stoppage controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve drivability and fuel efficiency, by shortening the lag time of fuel stoppage when deceleration-time fuel reduction is under way and a prescribed condition, under which a fuel stoppage means is put in action, exists. CONSTITUTION:An electronic control circuit 20 functions so that when the rotational frequency of an internal-combustion engine 1 detected by a rotation angle sensor 18 is higher than a prescribed level and an idling switch in a throttle sensor 11 is turned on, fuel stoppage is performed after the lapse of a prescribed time. If it is then judged that is is necessary to perform deceleration-time reduction control on the quantity of injected fuel because the output of an intake pipe pressure sensor 15 is showing a negative change larger than a prescribed value, a fuel injection time reduction rate most appropriate to the change in the pressure in an intake pipe is retrieved from a map stored in a ROM 31, to perform reduction control on the quantity of injected fuel, and a prescribed time is greatly shortened to quickly perform fuel stoppage control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel stop control device for an internal combustion engine that executes fuel cut control and fuel reduction control during deceleration.
The present invention relates to a fuel stop control device for an internal combustion engine that achieves the fusion of the above fuel cut control and deceleration reduction control.

[Prior art] Conventionally, as a method of controlling the amount of fuel supplied to an internal combustion engine, in order to improve fuel efficiency, purify exhaust gas, and prevent overheating of the catalyst, when the internal combustion engine is decelerated, the amount of fuel supplied to the internal combustion engine has been controlled to the extent that the internal combustion engine does not stop. There are some that execute so-called fuel cut control, such as stopping fuel supply.

This type of control device usually detects the engine speed related to internal combustion and the throttle valve opening, and detects when the engine speed is at least a predetermined speed and the throttle valve is fully open or almost fully open. The fuel cut control is configured to be executed after a predetermined delay period has passed from the time when the condition is satisfied. This is to avoid the chattering phenomenon that occurs in the idle switch output, which is one of the requirements for the above condition to be met, and the deterioration of drivability caused by immediately cutting fuel when the condition is met, and to achieve the above purpose. Control is executed after a delay period (for example, several hundred milliseconds) has elapsed, as disclosed in Japanese Patent Application Laid-open No. 1347-1983, for example.

By the way, some of the fuel supplied to the internal combustion engine always adheres to the inner wall of the intake pipe or the intake boat, and the fuel that is drawn into the combustion chamber is composed of fuel that has not adhered to the fuel that has been supplied and fuel that has adhered in the past. These include vaporized fuel and fuel that has previously adhered to the wall and peeled off from the wall. When the operating conditions of an internal combustion engine are constant, the amount of fuel that is newly attached to the wall and the amount of fuel that is vaporized or peeled off is approximately the same, and the amount of fuel that is attached to the wall is approximately constant and balanced. There is. That is, as the amount of fuel that adheres increases, the amount of fuel that vaporizes or peels off also increases, and conversely, when the amount of fuel that adheres decreases, the amount of fuel that vaporizes or peels off also decreases, so there is always a balance to be struck.

This balance point is determined by the operating conditions of the internal combustion engine at that time. When the intake pipe pressure is high, it is difficult for the fuel to vaporize, so the balance will not be achieved unless more fuel adheres to the engine.On the other hand, when the intake pipe pressure is low, the balance will be achieved with less fuel adhering. In addition, when an internal combustion engine is operated at high speeds, the air-fuel ratio is enriched to lower the temperature of exhaust gas or to prevent knocking, or to increase output during high loads. When the number of fuel teeth is large compared to the amount of intake air, the amount of fuel that newly adheres to the wall surface also increases, so the amount of fuel that adheres to the wall surface in order to achieve the amount of vaporization or peeling that balances this amount is Of course there will be more.

Under the above-mentioned conditions, when the throttle valve of an internal combustion engine is closed from the opening degree under a certain load to fully open or close to it, the following phenomenon occurs.

When a certain load is applied, the pressure inside the intake pipe is high, and when the load is high, the amount of fuel that adheres to the wall increases because the amount of fuel is increased to obtain output. When the throttle is suddenly closed in this state, the pressure inside the intake pipe drops rapidly, causing the fuel adhering to the wall to vaporize at once and be sucked into the combustion air.

On the other hand, fuel injection control assumes that there is a balance between fuel adhering to the wall and vaporization or separation from the adhering fuel, and continues to supply the optimal amount of fuel, so that the fuel adhering to the wall is removed from the fuel. The air-fuel ratio becomes overrich due to the increase in intake fuel.

When the above-mentioned overrich occurs, the operating condition of the internal combustion engine becomes unstable, so conventionally, when a sudden decrease in the internal combustion engine rotation speed or intake pipe negative pressure such as intake pipe negative 1 is detected, fuel injection is stopped. For example, Japanese Patent Application Laid-Open No. 150934/1983) has been used to reduce the amount of fuel to avoid overriching, so-called reduction control during deceleration.

[Problems to be Solved by the Invention] However, even if there is a fuel stop control device for an internal combustion engine that executes the fuel cut control and deceleration reduction control as described above, it is still not sufficient and has the following problems. had.

In other words, the above two controls, fuel cut control and deceleration weight loss control, have no correlation and are executed as completely independent controls, resulting in the following problems. ing. Figure 2 shows changes in the intake pipe pressure of the internal combustion engine (Figure (A)), the reduction rate of fuel injected and supplied to the internal combustion engine at that time (Figure B), and the execution timing of fuel cut control (Figure (C)). Figure) are shown respectively. As shown in the figure, when a sudden decrease in the intake pipe pressure of the internal combustion engine is observed, the reduction rate of the fuel injection amount gradually increases through deceleration reduction control, reducing the amount of fuel injected into the internal combustion engine until a certain peak point. This time, the reduction rate is gradually reduced and operation of the internal combustion engine with the normal fuel injection amount is resumed. On the other hand, although the conditions for executing the fuel cut control are also satisfied when the internal combustion engine is decelerated (time t1), the actual fuel cut is executed after a certain delay period (TD': several hundred ms) has elapsed due to the above-mentioned reason.

When the above control is executed on an internal combustion engine, the air-fuel ratio changes to the lower side to some extent due to the deceleration reduction control, and then after the deceleration reduction control ends until the fuel injection is actually cut. During period T, the state returns to normal,
Furthermore, due to the fuel cut, the fuel will be changed to an extremely lean side again.

Therefore, the torque generated by the internal combustion engine fluctuates considerably, causing deterioration of drivability during deceleration. Further, the fuel injected and supplied at the normal concentration during the period T is unnecessary for the fuel cut control to be executed in the future, and is not preferable from the viewpoint of improving fuel efficiency.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an excellent fuel stop control device for an internal combustion engine that can improve drivability and fuel efficiency during deceleration of the internal combustion engine.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the means constructed according to the present invention is, as shown in the basic configuration diagram of FIG. 1, operating state detection means for detecting the operating state of the internal combustion engine C1. C2; a fuel injection means C3 for injecting and supplying an amount of fuel to the internal combustion engine C1 according to the detection result of the operating state detection means C2; and from the time when the detection result of the operating state detection means C2 satisfies a predetermined condition. a fuel cut means C4 that stops the operation of the fuel injection means C3 after a predetermined delay period; and when the operating state detection means C2 detects a predetermined deceleration state, reduces the amount of fuel injected and supplied by the fuel injection means C3. In a fuel stop control device for an internal combustion engine having a deceleration reducing means C5, when the decelerating reducing means C5 is executing fuel reduction and the predetermined condition for operating the fuel cut means C4 is satisfied. The gist of the present invention is a fuel stop control device for an internal combustion engine, which is characterized by comprising a period shortening means C6 for shortening a predetermined delay period of the fuel cut means C4.

[Function] The period shortening means C6 in the present invention has the following function. When the internal combustion engine C1 is decelerating, the deceleration reduction means C5 operates to reduce the amount of fuel injected and supplied by the fuel injection means C3. Furthermore, under such conditions, it is clear that the predetermined conditions for the operation of the fuel cut means C4 are extremely likely to be satisfied, but the actual operation of this fuel cut means C4 is not normal. For example, after a predetermined delay period has elapsed since the above condition was satisfied. Therefore, the period shortening means C6 operates only when the deceleration reduction means C5 is performing a reduction operation and the predetermined condition for the fuel cut is satisfied, and shortens the delay period. As mentioned above, the delay period is set to ensure drivability by executing a fuel cut, but as long as deceleration dark decay is in progress, the internal combustion engine is already running lean. Even if a fuel cut is immediately executed, drivability will not be adversely affected. Therefore, the predetermined delay time of the fuel cut means C4 is shortened only during execution of the deceleration reduction means C5.

Note that the shortening performed by the period shortening means C6 may be of any degree; for example, the delay period may be set to "0" to completely eliminate the delay, or a number + [ to avoid only chattering of the idle switch output. ms] or the like.

In addition, the degree of reduction is made variable depending on the operating state of the internal combustion engine, and for example, a relatively long delay period is applied at the beginning of the deceleration reduction control by the deceleration reduction means c5, and immediate fuel cut control is performed at the end of the deceleration reduction control. For execution, the delay period may be shortened to approximately fOJ.

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

[Embodiment] First, FIG. 3 is a schematic configuration diagram showing an internal combustion engine equipped with a fuel stop control device according to an embodiment of the present invention and its peripheral devices together with a block diagram of an electronic control circuit.

1 is the internal combustion engine body, 2 is the piston, 3 is the 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 the exhaust gas, 6 is a fuel injection valve that injects fuel into the intake air of the internal combustion engine body 1, 7 is an intake manifold, and 8 is an oxygen sensor An intake air temperature sensor detects the temperature of the intake air sent to the internal combustion engine main body 1, 9 a water temperature sensor that detects the temperature THW of internal combustion engine cooling water, 10 a throttle valve, and 11 a built-in idle switch for opening of the throttle valve. Throttle sensor that detects 1
Reference numeral 4 represents a surge tank that absorbs pulsation of intake air, and reference numeral 15 represents an intake pipe pressure sensor that detects the intake pipe pressure within the surge tank 14, that is, the intake pipe pressure.

16 is an igniter that outputs the high voltage necessary for ignition; 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; and 18 is a distributor 17 The rotation angle sensor 19 outputs 24 pulse signals for one revolution of the distributor 17, that is, two revolutions of the crankshaft, and 19 outputs one pulse signal for one revolution of the distributor 17. 20 is an electronic control port/route as a control means, 21 is a key switch, 22 is a key switch 2
1 represents a battery that supplies power to the electronic control circuit 2o, 24 represents an on-vehicle transmission, and 26 represents a vehicle speed sensor that detects the vehicle speed from the rotational speed of the output shaft of the transmission 24.

Furthermore, the internal configuration of the electronic control circuit 20 will be explained as follows.
In the figure, 30 is a central processing unit (CPLJ) that inputs and calculates data output from each sensor according to a control program and performs processing to control the operation of various devices, and 31 stores control programs and initial data. read-only memory (ROM),
32 is a random access memory (RAM) in which data input to the electronic control circuit 20 and data necessary for arithmetic control are temporarily read and written; 33 is a random access memory (RAM) in which the real time for control can be read at any time by the CPU 30; C.P.
The register that causes the interrupt routine to U30 (hereinafter referred to as
36 is an input port for inputting signals from each sensor; 38 is an igniter 16;
and an output boat for driving the fuel injection valves 6 provided in each cylinder. Reference numeral 39 is a common bus that interconnects each of the above elements. The input boat 36 has an oxygen sensor 5. Intake temperature sensor 8. Water temperature sensor9. Throttle sensor 11° An analog input section (not shown) that A/D converts and inputs an analog signal from the intake pipe pressure sensor 15, and the throttle sensor 11.
An idle switch (not shown) and a rotation angle sensor 18.
It consists of a pulse input section (not shown) into which a pulse signal from the cylinder discrimination sensor 19 is input. Also, output boat 3
8 outputs a control signal to open the fuel injection valve 6 when receiving a command from the CPU 30 to start fuel injection, and this control signal is output until the output boat 38 receives a signal from the CPU 30 commanding the end of fuel injection. continue. The command to end the fuel injection is sent to the conveyor A inside the timer 33 by the CPU.
30 and the fuel injection end time set by timer 33
It is configured to be given by a conveyor A match interrupt routine (described later) which is generated when the continuously counted real time matches the conveyor A match interrupt routine (described later).

Next, regarding the control executed by the fuel injection amount control device of this embodiment, we will first explain the basic control routine of the internal combustion engine according to chart 70 in FIG. 4, and then control the start of normal fuel injection. Regarding the 30° CA interrupt routine to be performed, based on the flowchart in FIG. 5 (A>), and further based on the flowchart in FIG. 5(B) regarding the conveyor A coincidence interrupt routine that controls the end of fuel injection. The main routine for controlling the fuel ht will be sequentially explained with reference to the flowchart in FIG. 6, and finally the deceleration reduction control routine that is sometimes executed during deceleration of the internal combustion engine will be explained in sequence with reference to the flowchart in FIG. .

As shown in FIG. 4, the basic control routine for the internal combustion engine 1 is started when the key switch 21 is turned on, and first performs initialization such as clearing the internal registers of the CPU 30 (step 100). Then, the initial values of data used to control the internal combustion engine 1 are set, for example, the flag FCUT indicating that a fuel cut is in progress is set to 0 (step 1.times.5). Next, the operating state of the internal combustion engine 1, for example, the intake pipe pressure sensor 151, the rotation angle sensor 18. Water temperature sensor 9
Step 11o
), from the various data read in this way, a process is performed to calculate various quantities that are the basis of control of the internal combustion engine 1, such as the intake pipe pressure PM and the rotational speed N of the internal combustion engine 1 (step 120). Hereinafter, based on the various quantities obtained in step 120, well-known ignition timing control (step 130) and fuel injection amount control (
Step 140) is performed. After step 140 ends, the process returns to step 110 and repeats the process described above.

Note that the control of the fuel injection amount here usually involves feedback control of the air-fuel ratio, and the basic fuel injection amount, which is determined based on the load of the internal combustion engine 1, is controlled by various correction terms such as an air-fuel ratio feedback correction coefficient. Synchronous injection is performed once per rotation of the internal combustion engine 1 using the corrected fuel injection amount, but an oven that increases the amount of fuel instead of air-fuel ratio feedback control according to various operational demands of the internal combustion engine 1 is used. control and other well-known controls. The basic control of these internal combustion engines, including ignition timing control, is well known, so a description thereof will be omitted.

Next, the 30° CA interrupt routine that controls the start of fuel injection will be explained using the flowchart in FIG. The routine starts as an interrupt routine in response to a pulse input from the rotation angle sensor 18, and starts from 1 to 12 every time a pulse is input from the rotation angle sensor 18, with the time point at which a pulse is input from the cylinder discrimination sensor 19 as zero at step 150.
A process is performed to determine the current crank angle by knowing the value of a counter (not shown) that is repeatedly counted up. In the following step 160, it is determined from the crank angle obtained in step 150 whether or not it is time to start injection. This is because the internal combustion engine 1 injects fuel once per revolution, and it is determined whether or not the current moment is at the crank angle at which fuel injection starts. If the determination at step 160 is rNOJ, it is determined that there is no need to start fuel injection, and the process exits to RTN and ends this interrupt routine. If the determination at step 160 is rYEsJ, the process proceeds to step 170, where it is determined whether the flag is FCUT-0. The flag FCUT is a flag indicating whether or not to implement a fuel cut, and its initial value is O, and is set depending on the operating state of the internal combustion engine 1 in the main routine described later with reference to FIG. It is something. Now, if the value of the flag FCUT is 1, it is assumed that a fuel cut is being performed, and the process exits to RTN and ends this interrupt routine. On the other hand, Flag FC
If it is UT-0, the process proceeds from step 170 to step 180, where a command signal is output to the output port 38 to start fuel injection, and the fuel injection valve 6 is opened. In the subsequent step 190, the value obtained by adding the fuel injection amount (fuel injection time T) obtained in step 140 in FIG. A process is performed to set it on conveyor A. After step 190 is completed, the process exits to RTN and ends this interrupt routine.

The conveyor A in the timer 33 continues to compare the set fuel injection end time t1 and the control real time Tr, and when the control real time Tr reaches the fuel injection end time t1,
An interrupt request is issued to the CPU 30, causing the conveyor to start a match interrupt routine. This is the routine shown in the flowchart of FIG. 5(B), and step 195
At this point, a signal for ending fuel injection is output to the output port 38, the fuel injection valve 6 is closed, and the fuel injection is ended. Immediately after completing the process in step 195, RT
N, and this conveyor A match interrupt routine ends.

The outline of fuel injection control has been described above, and next, the main routine for performing fuel cut control will be described with reference to the flowchart of FIG. This routine is repeatedly executed as part of the fuel injection amount control g (step 140) shown in FIG. . To explain each determination from step 200 to step 240 of the area D1 in FIG. 5, each step is as follows.
Determining whether UT (initial value zero) is 1, step 210: If the rotation speed N of the internal combustion engine 1 is 150 Or
Step 220: Determine whether the rotation speed N of the internal combustion engine 1 is less than 1700 rpa+. Step 230: Whether the idle switch in the throttle sensor 11 is turned off. Step 240: Similarly, it is determined whether the idle switch is on, that is, whether the throttle valve 10 is fully open or not.

The three branch schools are: (a') In step 250, the final fuel injection time T for opening the fuel injection valve 6 is calculated, and in step 260, the timer TCUT set in step 290, which will be described later, is reset. Then, in step 270, the flag FCUT is set to O to cancel the fuel cut, and when the main routine is exited to NEXT, (b) In step 275, the timer TCUT is reset in the same manner as in step 260 described above, and the <O) In step 280, timer TCUT is set;
It is determined whether or not time counting has started, and if it has not been set, it is set once in step 290. Then, in the following step 300, it is determined whether the weight loss rate KPM for weight loss during deceleration, which will be described later, is "0", that is, whether weight loss control during deceleration is not being executed, and if KPM-0 is not executing the control, the process proceeds to step 310. Then, it is determined whether or not the timer TCLJT set in step 290 has counted the elapse of 200 [11S], and only when 200 [ms] have elapsed, the process of step 320 is performed, that is, the flag FCtJT is set to 1.
After performing the processing to set the value, the process exits to NEXT and the main routine ends. On the other hand, when KPM≠O and the control is being executed, step 330 is executed, and it is determined whether or not the timer TCUT has counted the elapse of 50 [11S].
[118] Only in the case of progress, after processing step 320 in the same manner as described above, the process exits to NEXT and ends the main routine.

Note that the determination of the final fuel injection time T executed in step 250 refers to the determination of the final fuel injection time T calculated in step 120 of FIG.
It is obtained by multiplying the normal basic fuel injection time Tp calculated based on M, N, etc. by the weight loss rate KPM determined in FIG. 7, which will be described later.

Therefore, to summarize the control of the main routine, if the flag FCtJT is 1 (and the rotational speed N of the internal combustion engine 1 is 170
0rl) Ill or below, or when the rotational speed N of the internal combustion engine 1 exceeds 170 rpm but the idle switch is off, the load on the internal combustion engine 1 is assumed to be sufficiently high, and the main routine is continued without performing any fuel cut or other operations. End (Step 200 - Step 220 - Step 275 - NEX
T or Step 200-Step 220-Step 2
40-Step 275-NEXT). On the other hand, flag F
If CUT is not 1 and its rotational speed N exceeds 170 rpm and the idle switch is on, the throttle valve 10 is fully open and the rotational speed is sufficiently high, so a fuel cut is performed. judge that it should be done. In this case, the flag FCUT is set to 1 after 200 [+113] has elapsed when the timer TCUT, which is counted from that point, is KPM-0, and after 50 [ms] has elapsed when KPM≠O, End the main routine (step 200 - step 220 - step 240 - step 280 or step 330 - NO)
XT). In this case, the normal fuel injection synchronized with the rotation of the internal combustion engine 1 will not be performed and the fuel cut will not be performed due to the determination in step 170 in the 30' OA interrupt routine already explained using the flowchart in FIG. 5(A). It will be implemented.

Next, after the flag FCUT becomes 1, if the rotation speed N of the internal combustion engine 1 is 150Q rpm or more and the idle switch remains on, it is assumed that the conditions for implementing the fuel cut continue, and nothing is done. The main routine ends (step 200-step 210-step 230-step 275-NEXT). However, when the rotational speed N of the internal combustion engine 1 gradually decreases to less than 1500 rlJ, or when the idle switch is no longer in the on state even if it is above 1500 rpm, a request for an increase in the output of the internal combustion engine 1 arises. At this time, it is assumed that the conditions for implementing the fuel cut are no longer present, and the processes of steps 250 and 260 are performed, followed by the process of step 270 in which the flag FCUT is set to O to cancel the fuel cut, and the main routine is terminated (step 20). - Step 210 - Step 250
or step 270-NEXT, or step 20
0-Step 210-Step 230-Step 250
or step 270-NEXT).

Therefore, by executing this main routine, fuel injection is normally performed in synchronization with the crank angle of the internal combustion engine 1 with an amount of fuel corresponding to the load of the internal combustion engine 1, and the load of the internal combustion engine 1 is lower than or equal to a predetermined value. When this happens, here, when the rotational speed of the internal combustion engine 1 exceeds 1700 rDm and the idle switch is on (throttle valve 10 fully closed), it is determined that the fuel cut control condition is satisfied, and the timer TCUT is set.
Start timing. If the deceleration reduction control is not being executed at that time (KPM-0), 20o[1
IIS] Temporarily stops the fuel injection and cuts the fuel after the elapsed time, and the reduction control during deceleration is being executed (KP, M≠0)
In some cases, after 50 [msl has elapsed, a fuel cut is similarly performed to temporarily stop fuel injection, and when the operating state of the internal combustion engine 1 reaches a predetermined state during the fuel cut, here, the internal combustion engine 1 When the rotational speed of the engine becomes less than 150 rpm or the idle switch is turned off, control is performed to cancel the fuel cut.

Next, two interrupt routines for calculating the fuel injection time reduction rate KPM used in steps 250 and 300 in FIG. Explain. (A) Figure 1
Interrupt processing is performed by the CPU 30 every 2 [mS]. First, in step 400, the output P of the intake pipe pressure sensor 15 is
A change ΔPM in M is calculated, and in the next step 410 it is determined whether the change ΔPM shows a negative change larger than -20 [m Hg]. In other words, it is determined whether the internal combustion engine 1 is in a state of sudden deceleration and it is necessary to control the amount of fuel injection to be reduced during deceleration.
Hlj], the processing of this routine is ended and ΔPM
Step 420 only when <-20 [m Ha ]
Then, the process of step 440 is performed. Step 420
Now, from the two-dimensional map of ΔPM-Δ stored in the ROM 31 in advance, determine the fuel injection time T most suitable for the value of ΔPM.
Search for the weight loss rate ΔK. Then, in step 430, the retrieved ΔK is added to the fuel injection time correction coefficient KPM, and in the subsequent step 440, the timer TPM is set to 8[n+s].
, and end this routine.

Here, the timer TPM subtracts the elapsed time from the set time.
[1Ils] Used in interrupt routine.

(B) In the 4 [ms] interrupt routine in the figure, the correction coefficient K
PM reduction is performed as needed. First, it is determined whether the correction coefficient KPM is already rOJ, and KPM-0
If so, the reduction process is no longer necessary and this routine ends. Step 510 is also for determining whether a reduction process is necessary, and here it is determined whether the timer TPM has elapsed for a set time and its contents have become rOJ. Then, when it is determined that the timer TPM is "0" and the necessary time has elapsed, the next steps 530 to 560 are processed, and otherwise, this routine is ended. First, in step 530, a predetermined amount α is subtracted from the correction coefficient KPM, and then in step 5
At 40,550, guard processing is performed to prevent the correction coefficient KPM from becoming a negative value due to the subtraction processing of the predetermined amount α.

Next, in step 560, the timer CPM is set to 4 [ms] as the necessary elapsed time until the next reduction process, and this routine ends.

The correction coefficient KPM determined in this way is the sixth
It is used in steps 250 and 300 in the figure to determine appropriate correction of the fuel injection time T and change in the timing of execution of the fuel cut control.

The operation of the fuel injection amount control device of this embodiment, which controls as described above, will be explained based on the explanatory diagram of FIG. 8. (A
) As shown in the figure, when the intake air amount of the internal combustion engine 1 suddenly decreases, the fuel injection time T is shortened by the correction coefficient KPM (reduction rate) as shown in (8), and normal deceleration reduction control is executed. I understand.

Further, when the fuel cut control condition is satisfied at time [2] during deceleration of the internal combustion engine 1, the timer TCUT is set as usual and starts timing. However, as mentioned above, if the deceleration weight loss control is being executed and the correction coefficient KPM takes a certain positive value, the delay period from the time when this condition is met is significantly shortened from the usual 200 [mS] to 50 mS. [n+s], and the execution of fuel cut control (setting of flag FCUT) is performed quickly. That is,
(C) As shown in the figure, the delay period is set to 200[
If the correction coefficient KPM is set to msl, the value of the correction coefficient KPM will be gradually decreased until it reaches KPM-0, and the fuel supply to the internal combustion engine 1 will increase. Then, after once returning to normal air-fuel ratio feedback control, execution of fuel cut control is started, and the air-fuel ratio of internal combustion engine 1 will change several times. In such a case, the torque of the internal combustion engine 1 naturally fluctuates, but according to the present fuel stop control device, the fuel cut is performed while the deceleration reduction control is still being executed after 50 [msl have elapsed from time t2. For,
The air-fuel ratio of the internal combustion engine 1 will smoothly transition to lean. This also prevents unnecessary fuel from being consumed by the internal combustion engine 1, and further improves fuel efficiency and emissions.

That is, according to this embodiment, the reduction control during deceleration and the fuel cut control are combined, making it possible to control the internal combustion engine 1 extremely well. Therefore, the transition from deceleration reduction control to fuel cut control becomes smooth, and fluctuations in torque that occur between the two control transitions are suppressed, and good drivability can be achieved. Further, since unnecessary fuel injection is not performed, fuel efficiency and emissions are improved, resulting in an excellent fuel stop control device for an internal combustion engine.

In this embodiment, the delay period of the fuel cut control during the execution of the deceleration reduction control is set to 50 [ms], but this is due to the hardware configuration of the idle switch built in the throttle sensor 11 when the idle switch is turned on. IS]
This is because consideration has been given to the case where some degree of chattering occurs. Therefore, if such consideration is unnecessary, the delay period may be set to O[msJ, and the fuel cut may be executed immediately when the condition is satisfied. Further, the delay period is not necessarily set to the same value, but more precise control may be performed, for example, by making it variable depending on the value of the correction coefficient KPM.

[Effects of the Invention] As described above in detail with reference to examples, the internal combustion el of the present invention
The fuel stop 111vA device according to the present invention includes: an operating state detecting means for detecting the operating state of the internal combustion engine; a fuel injection means for injecting and supplying an amount of fuel to the internal combustion engine according to a detection result of the operating state detecting means; a fuel cut means for stopping the operation of the fuel injection means after a predetermined delay period has elapsed from the time when the detection result of the driving state detecting means satisfies a predetermined condition; and when the driving state detecting means detects a predetermined deceleration state; In the fuel injection amount control device for an internal combustion engine, the fuel injection amount control device has a deceleration reducing means for reducing the amount of fuel injected and supplied by the fuel injection means; The present invention is characterized by comprising period shortening means for shortening a predetermined delay period of the fuel cut means when the predetermined condition for activation is satisfied.

Therefore, it is possible to mutually integrate the deceleration reduction control and the fuel cut control, which are executed when the internal combustion engine decelerates, to realize smooth control.

For this reason, drivability during deceleration of the internal combustion engine,
All aspects such as fuel efficiency and emissions can be improved, and the operating performance of the internal combustion engine will be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 (A) (B),
(C) is an explanatory diagram of deceleration weight loss control and fuel cut control;
Fig. 3 is a schematic configuration diagram showing an internal combustion engine equipped with a fuel stop control device according to an embodiment of the present invention and its peripheral devices together with a block diagram of an electronic control circuit, and Fig. 4 is a basic diagram of an internal combustion engine used in the embodiment. FIG. 5 is a flowchart showing a typical control routine (A> is a flowchart showing a 30'CA interrupt routine that also controls the start of fuel injection.
Diagram (B) shows conveyor A that also controls the end of fuel injection.
FIG. 6 is a flowchart showing the coincidence interrupt routine, FIG. 6 is a flowchart showing the main routine, FIG. 7 is a floorchart for executing deceleration reduction, and FIG.
1118] Flowchart of the interrupt miroutine, (B) is a flowchart of the 4[mS1 interrupt routine, and FIGS. 8A, 8B, and 8C are explanatory diagrams of the control of the embodiment. C1...Internal combustion engine C2...Operating state detection means C3...Fuel injection means C4...Fuel cut means C5...Deceleration reduction means C6...Period reduction means 1...Internal combustion engine 6 ... Fuel injection valve 11 ... Throttle sensor, ° 15 ... Intake pipe pressure sensor 20 ... Electronic control circuit 30 ... CPU

Claims (1)

[Scope of Claims] Operating state detection means for detecting the operating state of an internal combustion engine; fuel injection means for injecting and supplying an amount of fuel to the internal combustion engine according to a detection result of the operating state detection means; and the operating state. a fuel cut means that stops the operation of the fuel injection means after a predetermined delay period has elapsed from the time when the detection result of the detection means satisfies a predetermined condition; and when the operating state detection means detects a predetermined deceleration state, the fuel In the fuel stop control device for an internal combustion engine, the fuel stop control device has a deceleration reducing means for reducing the amount of fuel injected by the injection means, when the decelerating reducing means is reducing the amount of fuel and the fuel cutting means operates at the predetermined time. When the conditions are satisfied,
A fuel stop control device for an internal combustion engine, comprising a period shortening means for shortening a predetermined delay period of the fuel cut means.