JPH0571382A - Fuel feed control device for engine - Google Patents

Abstract

PURPOSE:To prevent worsening of emission owing to turbulence of an air-fuel ratio by prohibiting fuel feed variation control not responding to an intake air amount when a fuel control demand responding to an acceleration opening is low (namely under a shift and right after a shift). CONSTITUTION:A fuel feed control device for an engine having a fuel feed varying means to effect the feed of fuel responding to an intake air amount and change a fuel feed amount during given accelerator operation is provided. Further, the fuel feed control device is provided with shift detecting means 32 and 33 to detect shift operation and a prohibiting means to prohibit fuel feed variation control effected by a fuel feed varying means under a shift and right after a shift based on detection of shift operation by means of the shift detecting means 32 and 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, supplies fuel corresponding to the intake air amount, and special fuel supply such as deceleration fuel cut control and acceleration asynchronous injection control (acceleration increase control) at the time of predetermined accelerator operation. The present invention relates to a fuel supply control device for an engine that performs variable control.

[0002]

2. Description of the Related Art Conventionally, as a device for performing the deceleration fuel cut control of the above-mentioned example, as described in, for example, JP-A-55-137339, the throttle opening is fully closed and the engine speed is a predetermined value ( It is known that fuel injection is stopped at a speed of about 1500 rpm or more to improve fuel efficiency and reduce emissions.

However, this conventional device has the following problems. For example, at the time of an acceleration shift from the 1st speed to the 2nd speed, the accelerator is returned, the clutch is released to bring it into a neutral state, a shift operation is performed, and then the accelerator is stepped on. At this time, the engine speed is as shown in FIG. Changes, and the deceleration fuel cut condition is satisfied. On the other hand, with respect to the fuel correction amount CFB, the condition of the engine greatly changes before and after the shift, so that it is not reliable to use the feedback correction amount before the shift as the value when the feedback is restarted after the shift. As shown in FIG. 8, control for resetting is performed. Therefore, when the fuel cut is executed by the satisfaction of the deceleration fuel cut condition described above during the acceleration shift, the actual air-fuel ratio changes as shown in FIG. 8, and the actual air-fuel ratio is disturbed in the hatched triangular portion a. However, there was a problem that the emission was deteriorated.

On the other hand, conventionally, as a device for performing the acceleration asynchronous injection control of the above-mentioned example, for example, Japanese Patent Laid-Open No. 61-205357.
As disclosed in Japanese Patent Publication, when the rate of change in throttle opening is equal to or greater than a predetermined value, fuel injection is executed asynchronously with normal fuel injection (synchronous injection) to improve acceleration performance. What you have done is known.

However, this conventional device has the following problems. That is, if the value of the rate of change of the throttle opening, which is the threshold value for asynchronous generation, is matched with the request at the time of acceleration, for example, at the time of the acceleration shift from the first speed to the second speed,
Asynchronous injection is executed as shown in, but the gear ratio is changed by the shift operation, and the engine speed is about 3000, for example.
Since the rpm is changed to about 1800 rpm, even if the acceleration asynchronous injection is executed, the driver cannot substantially feel it. Moreover, there is a problem that the actual air-fuel ratio changes as shown in FIG. 8 due to the above-described acceleration asynchronous injection, the actual air-fuel ratio is disturbed in the hatched rectangular portion b, and the emission deteriorates.

[0006]

SUMMARY OF THE INVENTION The invention according to claim 1 of the present invention is a variable fuel supply control which does not correspond to the intake air amount when the fuel control demand corresponding to the accelerator opening is small (during gear shift and immediately after gear shift). It is an object of the present invention to provide a fuel supply control device for an engine, which is capable of preventing deterioration of emission due to disturbance of air-fuel ratio.

According to a second aspect of the present invention, the deceleration fuel cut control is prohibited during the shift and immediately after the shift so that the deterioration of the emission due to the disturbance of the air-fuel ratio can be prevented. The purpose is to provide a device.

According to a third aspect of the present invention, the fuel supply of the engine capable of preventing the deterioration of the emission due to the disturbance of the air-fuel ratio by prohibiting the fuel quantity increase during acceleration during and immediately after the above-mentioned gear change. It is intended to provide a control device.

In the invention according to claim 4 of the present invention, the intake air amount is gradually reduced over a predetermined time so that a sudden negative pressure change does not occur, and in other words, after the reduction is completed, I
The SC valve corrects the dashpot, and the ISC
In the case where the deceleration fuel cut is executed after the lapse of a predetermined time when the dashpot correction amount becomes zero, the deceleration fuel cut control is prohibited during the gear shift and immediately after the gear shift to prevent the deterioration of the emission due to the disturbance of the air-fuel ratio. An object of the present invention is to provide a fuel supply control device for an engine.

According to a fifth aspect of the present invention, the variable fuel supply control that does not correspond to the intake air amount is prohibited for a predetermined time (during and immediately after the shift) from the time when the interruption of the power transmission path is detected. Therefore, it is an object of the present invention to provide an engine fuel supply control device capable of preventing deterioration of emission due to disturbance of the air-fuel ratio.

[0011]

The invention according to claim 1 of the present invention is provided with fuel supply variable means for supplying fuel corresponding to the intake air amount and changing the fuel supply amount when a predetermined accelerator operation is performed. A fuel supply control device for an engine, comprising: a shift detecting means for detecting a shift operation; and a fuel supply variable control by the fuel supply varying means during and immediately after a shift based on detection of the shift operation by the shift detecting means. The fuel supply control device for an engine is provided with a prohibition means for prohibiting.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the fuel supply varying means cuts the supplied fuel when the accelerator opening is equal to or smaller than a predetermined opening. It is characterized by being a fuel supply control device for an engine which is a cutting means.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the invention, when the rate of change of the accelerator opening in the increasing direction is a predetermined value or more, It is a fuel supply control device for an engine, which is an acceleration fuel amount increasing means for increasing the supply fuel amount.

According to the invention of claim 4 of the present invention, in combination with the structure of the invention of claim 2, the intake air amount is gradually reduced over a predetermined time from the time when the accelerator is fully closed, and the reduction is completed. It is a fuel supply control device for an engine that later executes the deceleration fuel cut.

According to a fifth aspect of the present invention, in addition to the configuration of the first aspect of the invention, the shift detecting means is such that the power transmission path is cut off by at least one of a gear switch and a clutch switch. The fuel supply control device for an engine is characterized in that the fuel supply control device prohibits the fuel variable control by the fuel supply variable means for a predetermined time from the time of detection of the power transmission path interruption.

[0016]

According to the first aspect of the present invention, the above-mentioned prohibiting means supplies the fuel by the fuel supply varying means during and immediately after the shift when the shift detecting operation detects the shift operation. Since the variable control of the fuel supply is prohibited, the variable fuel supply control that does not correspond to the intake air amount is prohibited during and immediately after the gear shift in which the fuel control request according to the throttle opening degree is small, and as a result, the emission due to the disturbance of the air-fuel ratio is suppressed. There is an effect that can prevent the deterioration of.

According to the second aspect of the present invention,
During and immediately after a shift when the shift operation is detected by the shift detecting means, the prohibiting means prohibits the stop control of the supplied fuel by the deceleration fuel cut means. Therefore, the emission due to the disturbance of the air-fuel ratio is similarly performed. There is an effect that can prevent the deterioration of.

According to the invention of claim 3 of the present invention,
During and immediately after the shift in which the shift operation is detected by the shift detecting means, the prohibiting means prohibits the fuel acceleration increase control by the acceleration fuel increasing means. There is an effect that the deterioration of emission can be prevented.

According to the invention of claim 4 of the present invention,
The intake air amount is gradually reduced over a predetermined time period during and immediately after the shift operation when the shift operation is detected by the above-described shift detecting means, and in other words, the ISC dashpot correction amount is zero after the reduction is completed. Since the deceleration fuel cut that is executed after the above condition is prohibited by the prohibiting means described above, there is an effect that the deterioration of the emission due to the disturbance of the air-fuel ratio can be prevented in the same manner as described above.

According to the invention of claim 5 of the present invention,
During the shift and immediately after the shift in which it is detected that the power transmission path is cut off by at least one of the gear switch and the clutch switch, the prohibiting means described above causes the fuel supply varying means (for example, the deceleration fuel cut means and the acceleration asynchronous injection means). Since the variable control of the fuel supply by) is prohibited, there is an effect that the deterioration of the emission due to the disturbance of the air-fuel ratio can be prevented in the same manner as described above.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The drawing shows a fuel supply control device for an engine. In FIG. 1, an air flow sensor 2 is connected to a rear position of an air cleaner 1 for purifying intake air.
Is configured to detect the intake air amount.

A throttle body 3 is connected to the rear of the air flow sensor 2 described above, and a throttle chamber 5 in the throttle body 3 is provided with a throttle valve 5 for controlling the amount of intake air. And this throttle valve 5
A surge tank 6 as an expansion chamber having a predetermined volume is connected to the downstream intake passage, an intake manifold 8 communicating with the intake port 7 is connected downstream of the surge tank 6, and an injector 9 is connected to the intake manifold 8. Are installed.

On the other hand, an intake valve 12 and an exhaust valve 13 which are opened and closed by a valve operating mechanism (not shown) are attached to the above-mentioned intake port 7 and exhaust port 11 which are in proper communication with the combustion chamber of the engine 10. Further, an ignition plug (not shown) having a spark gap facing the combustion chamber is attached to the cylinder head.

An O 2 sensor 15 as an air-fuel ratio sensor is provided in the exhaust passage 14 communicating with the above-mentioned exhaust port 11, and a catalytic converter, a so-called catalyst, for detoxifying harmful gas is provided in the rear of the exhaust passage 14. Connected.

By the way, a bypass passage 16 for bypassing the above-mentioned throttle valve 5 is provided.
While an ISC valve 17 as an ISC (idle speed control) mechanism is installed in the air cleaner 1,
An intake air temperature sensor 19 is provided downstream of the element 18, a throttle sensor 20 is provided on the throttle body 3, and a water temperature sensor 21 is provided on the water jacket.

FIG. 2 shows a control circuit of the fuel supply control device for the engine. The CPU 30 has an intake air temperature from the intake air temperature sensor 19, an intake air amount from the air flow sensor 2, a throttle opening from the throttle sensor 20, and a water temperature sensor. 21 the temperature of the engine cooling water, the engine speed from the distributor 22, the voltage corresponding to the air-fuel ratio from the O2 sensor 15, the gear switch 2 that is turned on when in neutral
The injector 9 is driven and controlled in accordance with a program stored in the ROM 25 on the basis of each signal input of the switch signal from the clutch switch 24 and the switch signal from the clutch switch 24 which is turned on when the clutch is turned off. (For example, data corresponding to 1 to 2 ses) (see FIG. 3), data corresponding to elapsed time t after starting (see FIGS. 6 and 7), deceleration fuel cut rotation speed N (data corresponding to 1500 rpm, for example) ( (See FIG. 6),
Necessary data such as data (see FIG. 7) corresponding to a predetermined value α of the throttle opening change rate is stored.

Here, the CPU 30 gradually reduces the intake air amount over a predetermined time from when the engine speed is equal to or higher than a predetermined speed and the accelerator opening is equal to or lower than the predetermined opening, and after the reduction is completed. In other words, the deceleration fuel cut means for cutting the supplied fuel after the elapse of the predetermined time when the ISC dashpot correction amount becomes zero (see the sixth step 66 in the flowchart shown in FIG. 6) and the accelerator opening increasing direction. When the rate of change is equal to or greater than a predetermined value, the fuel amount increase means for acceleration for increasing the supplied fuel, specifically, the rate of change ΔT of the throttle opening.
When VO is greater than or equal to the predetermined value α, the power transmission path is shut off by the acceleration asynchronous injection means for increasing the supply fuel (see the sixth step 76 in the flowchart shown in FIG. 7) and at least one of the gear switch 23 and the clutch switch 24. Based on the fact that the gear shift operation is detected, the gear shift detection means (see the second step 32 and the third step 33 of the flowchart shown in FIG. 3) and the gear shift operation and the gear shift based on the detection of the gear shift operation by the gear shift detection means described above. Immediately after that, prohibiting means for prohibiting the deceleration fuel cut control and the acceleration asynchronous injection control (see the seventh step 67 of the flowchart shown in FIG. 6 and the seventh step 77 of the flowchart shown in FIG. 7).
Also serves as.

The operation of the engine fuel supply control device thus constructed will be described with reference to the flow charts of FIGS. 3, 6 and 7.

First, with reference to the flow chart of FIG. 3, a prohibition flag F used for prohibiting special variable fuel supply control such as deceleration fuel cut and acceleration asynchronous injection as an example of fuel amount increasing means during acceleration is set and reset. The processing to be performed will be described.

In the first step 31, the CPU 30 reads the signals of the gear switch 23 and the clutch switch 24, and in the next second step 32, the CPU 30 determines whether or not the gear switch 23 is ON, in other words, whether or not the gear switch 23 is neutral. If it is neutral, the process moves to the fifth step 35, while if it is not neutral, the next third step 3
Move to 3.

In the above-mentioned third step 33, the CPU 30 determines whether or not the clutch switch 24 is ON, in other words, whether or not the clutch is OFF, and when the clutch is OFF (when the clutch switch 24 is ON), the above-mentioned operation is performed. Fifth step 35
While the clutch is ON (clutch switch 2
4 is OFF), the process proceeds to another fourth step 34.
In other words, when the shift lever is operated to the neutral position during the gear shift operation or when the power transmission path is cut off when either of the conditions is established when the clutch petal is stepped on and the clutch is turned off, the above-described fifth step 35 is performed. ..

In the fifth step 35, the CPU 30 sets the neutral flag X (X = 1), while in the fourth step 34 described above, the CPU 30 resets the neutral flag X (X = 0).

Next, in a sixth step 36, the CPU 30 determines whether or not the previous neutral flag X [i-1] is 1, and the neutral flag X is set to 1 for the first time by the shift operation of this time.
When it becomes, the process proceeds to the next seventh step 37, while the neutral flag X of both the previous time and the current time is 1, the process proceeds to another eighth step 38 when the neutral continues.

In the above-mentioned seventh step 37, the CPU 30 sets the counter C to an initial value K, for example, a value corresponding to 1 to 2 seconds. Since the process of setting the counter C to the initial value K is performed at the moment when it becomes neutral for the first time,
From the next time on the flow chart, the sixth step 36 is followed by the eighth step 38, and the eighth step 3
At 8, the CPU 30 decrements the counter C.

Next, in a ninth step 39, the CPU 30 determines whether or not the value of the counter C is positive, and if the counter C is positive, the process moves to the next tenth step 40, while the counter C is zero. In that case, the process proceeds to another eleventh step 41.

In the tenth step 40 described above, the CPU 30
Sets the inhibition flag F (F = 1), while the CPU 30 resets the inhibition flag F (F = 0) in the eleventh step 41 described above. The prohibition flag F set in the flowchart shown in FIG. 3 is used for the deceleration fuel cut control and the acceleration asynchronous injection control shown in FIGS. 4 to 7.

FIG. 4 is an AND logic block diagram when executing the deceleration fuel cut control, and FIG. 5 is an AND logic block diagram when executing the acceleration asynchronous injection control. From the respective logic block diagrams, the above-mentioned prohibition flag F is shown. = 1, that is, during deceleration and immediately after the deceleration, deceleration fuel cut control is prohibited, and
Although it is clear that the acceleration asynchronous injection control is prohibited,
Hereinafter, these points will be described with reference to the flowcharts of FIGS. 6 and 7.

Execution of deceleration fuel cut control and prohibition processing will be described with reference to the flowchart of FIG. 6. In a first step 61, the CPU 30 determines whether or not a predetermined time t has elapsed after the engine is started, and the engine is started. In order to remove the later unstable time, the process proceeds to the next second step 62 only when the time t described above has elapsed.

In this second step 62, the CPU 30 determines whether or not the current engine speed Ne is larger than a predetermined engine speed N for deceleration fuel cut determination, for example 1500 rpm, and only when Ne> N, the next No. 3 shifts to the step 63.

In this third step 63, the CPU 30 determines whether or not the throttle opening TVO is fully closed, and only when TVO is fully closed, the CPU 30 proceeds to the next fourth step 64, and in this fourth step 64, the CPU 30 Whether or not the ISC dashpot correction amount Dp is zero is determined, and only when Dp = 0, the following fifth
Control goes to step 65.

In the fifth step 65, the CPU 30 determines whether the prohibition flag F = 0 or not, and when F = 0, moves to the next sixth step 66, while when F = 1, another seventh step 67 is executed. Transition.

In the above-mentioned sixth step 66, the CPU 30 executes the deceleration fuel cut control in response to all the conditions shown in FIG. 4, while in the above-mentioned seventh step 67, the CP is executed.
U30 is a corresponding prohibit flag F during and immediately after the shift.
The deceleration fuel cut control is prohibited based on = 1 to prevent the emission from deteriorating due to the disturbance of the air-fuel ratio.

Next, referring to the flowchart of FIG. 7, the execution of the acceleration asynchronous injection control and the inhibition processing will be described. In the first step 71, the CPU 30 determines whether or not a predetermined time t has elapsed after the engine start, In order to eliminate the unstable time after the engine is started, the process proceeds to the next second step 72 only when the time t described above has elapsed.

In the second step 72, the CPU 30 determines whether the engine is stopped or not, and the CPU 30 proceeds to the next third step 73 only when the engine is not stopped. In the third step 73, the CPU 30 changes the throttle opening. Rate ΔTV
It is determined whether or not O is larger than the predetermined value α, and only when ΔTVO> α, the process proceeds to the next fourth step 74.

In the fourth step 74, the CPU 30 determines whether or not the throttle opening TVO is in the non-fully closed state. Only when the TVO is not fully closed, the CPU 30 proceeds to the next fifth step 75, and in the fifth step 75. The CPU 30 determines whether the prohibition flag F = 0 or not, and when F = 0, moves to the next sixth step 76, while when F = 1, moves to another seventh step 77.

In the above-mentioned sixth step 76, the CPU 30 executes the acceleration asynchronous injection control in response to the satisfaction of all the conditions shown in FIG.
30 is a prohibition flag F =
The acceleration asynchronous injection control is prohibited based on 1 to prevent the emission from deteriorating due to the disturbance of the air-fuel ratio.

In short, the above-mentioned prohibiting means (the seventh step in FIG. 6) is executed during and immediately after the shift when it is detected that the power transmission path is blocked by at least one of the gear switch 23 and the clutch switch 24. 67 and the seventh step 77 in FIG. 7) prohibit the variable control of the fuel supply by the deceleration fuel cut means (see the sixth step 66 in FIG. 6) and the acceleration asynchronous injection means (see the sixth step 76 in FIG. 7). .. For this reason, the fuel supply variable control that does not correspond to the intake air amount is prohibited during and immediately after the shift in which the fuel control request according to the accelerator opening degree is small. Therefore, as shown by hatching in FIG. There is an effect that it is possible to prevent the deterioration of emission due to the disturbance of the air-fuel ratio at the time of various acceleration upshifts.

In the correspondence between the configuration of the present invention and the above-described embodiment, the fuel supply varying means of the present invention corresponds to the deceleration fuel cut means and the fuel quantity increasing means during acceleration of the embodiment,
Similarly, the gear shift detecting means corresponds to the second step 32 and the third step 33 of the flowchart of FIG. 3, and the prohibiting means is the seventh step 67 of the flowchart of FIG. 6 and the seventh step 77 of the flowchart of FIG. 6, the deceleration fuel cut means corresponds to the sixth step 66 of the flowchart of FIG. 6, and the acceleration asynchronous injection means as an example of the fuel amount increase during acceleration corresponds to the sixth step 76 of the flowchart of FIG. 7. , The process of determining that the ISC dashpot correction amount becomes zero corresponds to the fourth step 64 in the flowchart of FIG. 6, but the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of drawings]

FIG. 1 is a system diagram showing a fuel supply control device for an engine of the present invention.

FIG. 2 is a control circuit block diagram of a fuel supply control device.

FIG. 3 is a flowchart showing a prohibition flag setting / resetting process.

FIG. 4 is an AND logic configuration diagram when executing deceleration fuel cut control.

FIG. 5 is an AND logic block diagram when executing acceleration asynchronous injection control.

FIG. 6 is a flowchart showing execution and prohibition processing of deceleration fuel cut control.

FIG. 7 is a flowchart showing execution and prohibition processing of acceleration asynchronous injection control.

FIG. 8 is a time chart for explaining the disturbance of the conventional air-fuel ratio.

[Explanation of symbols]

 23 ... Gear switch 24 ... Clutch switch 32 ... 2nd step (shift detection means) 33 ... 3rd step (shift detection means) 66 ... 6th step (deceleration fuel cut means) 67 ... 7th step (prohibition means) 76 ... 6th step (acceleration asynchronous injection means) 77 ... 7th step (prohibition means)

Claims (5)

[Claims] 1. A fuel supply control device for an engine, comprising: a fuel supply control means for supplying fuel corresponding to an intake air amount; and a fuel supply varying means for changing the fuel supply amount when a predetermined accelerator operation is performed. A fuel supply control device for an engine, comprising: a shift detecting means; and a prohibiting means for prohibiting the variable fuel supply control by the variable fuel supply means during and immediately after the shift based on the detection of the shift operation by the shift detecting means. 2. The fuel supply control device for an engine according to claim 1, wherein the fuel supply variable means is a deceleration fuel cut means for cutting the supplied fuel when the accelerator opening is equal to or smaller than a predetermined opening. 3. The fuel supply control for an engine according to claim 1, wherein the fuel supply varying means is an acceleration fuel increasing means for increasing the supplied fuel when the rate of change of the accelerator opening in the increasing direction is a predetermined value or more. apparatus. 4. The fuel supply control device for an engine according to claim 2, wherein the intake air amount is gradually reduced over a predetermined time after the accelerator is fully closed, and the deceleration fuel cut is executed after the reduction is completed. 5. The shift detection means detects that the power transmission path is cut off by at least one of a gear switch and a clutch switch, and the fuel supply variable means fuels the fuel for a predetermined time after the power transmission path cutoff is detected. The fuel supply control device for an engine according to claim 1, wherein the variable supply control is prohibited.