JPH0986227A - Fuel supply control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the smooth execution of fuel supply cut-off from being impeded by down-shift of a change gear ratio at the time of deceleration by shortening first specified time and reducing specified rotating speed at the time of executing decelerating shift processing by an output control means. SOLUTION: An automatic transmission 20 with four gear speeds is connected to the output shaft of an engine, and the automatic transmission 20 is provided with a control valve(CV) 21 for producing operating oil for switching a change gear ratio and the like. The CV 21 is connected to an ECU 5, and the action of the CV 21 is suppressed by a signal from the ECU 5. The shift position (speed change position) of the automatic transmission 20 is detected by a shift position(PS) sensor 22, and a detection signal from the PS sensor 22 is supplied to the ECU 5. The automatic transmission 20 is provided with a vehicle speed(VP) sensor 23 for detecting vehicle speed from the rotating speed of its output shaft, and a detection signal from the VP sensor 23 is supplied to the ECU 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device which cuts off fuel supply to an internal combustion engine during deceleration.

[0002]

2. Description of the Related Art In a general vehicle internal combustion engine,
At the time of predetermined deceleration, so-called fuel cut is performed to cut off the fuel supply to the internal combustion engine in order to improve fuel efficiency.

As a method for interrupting fuel supply during deceleration, a fuel cut execution determination engine speed and a return determination engine speed are set, and a fuel cut execution condition is determined based on the throttle valve opening. When the engine speed is satisfied, it is determined whether or not the engine speed is higher than the fuel cut execution determination engine speed. When the engine speed is higher than the fuel cut execution determination engine speed, the first from the time when the fuel cut execution condition is satisfied. When the fuel supply to the engine is cut off after a lapse of a predetermined time, and the engine speed drops below the return determination engine speed after the cutoff of the fuel supply, the fuel supply to the engine is restored and a second predetermined time is elapsed after the fuel supply is returned. Fuel cut execution determination Some increase the engine speed by a predetermined speed.

When the engine speed is higher than the fuel cut execution determination engine speed, the fuel supply to the engine is cut off after the first predetermined time has elapsed from the time when the fuel cut execution condition is satisfied. Fluctuations can be suppressed, and shocks given to occupants are alleviated to improve drivability during deceleration.

Further, when the fuel supply is restored, the fuel cut execution determination engine rotation speed is increased by the predetermined rotation speed for the second predetermined time. Therefore, after the fuel supply is restored, the fuel supply cutoff and the fuel supply return are repeatedly performed again. It is possible to prevent the occurrence of hunting.

When this fuel supply cutoff method during deceleration is applied to a vehicle provided with an automatic transmission, the engine rotational speed temporarily increases due to the transmission torque from the torque converter of the automatic transmission during deceleration. By increasing the fuel cut execution determination engine rotation speed for the second predetermined time by the predetermined rotation speed, it is possible to prevent the occurrence of hunting due to the increase in the engine rotation speed due to the transmission torque.

In order to improve fuel economy, a downshift control method has been proposed in which the gear ratio of the automatic transmission is switched to the low speed side during deceleration.

[0008]

However, when a downshift control method for switching the gear ratio of the automatic transmission to the low speed side during deceleration is adopted in a vehicle with automatic transmission that executes the above-described fuel supply cutoff method during deceleration, Although the engine speed increases during the downshift control, the increased engine speed may not exceed the fuel cut execution determination engine speed due to the increase in the fuel cut execution determination engine speed. It is possible that the fuel supply cutoff will not be executed, or the start of fuel supply stop during deceleration will be delayed, etc., and a sufficient fuel efficiency improvement effect during deceleration and the shock given to the occupant due to the fuel supply cutoff during deceleration For example, the effect of improving drivability during deceleration and engine speed after the fuel supply is restored. It is difficult to achieve both ring prevention effect.

The present invention has been made by paying attention to this point, and there is no fear that smooth execution of fuel supply cutoff may be hindered by downshifting of the gear ratio during deceleration shift, and sufficient fuel efficiency improvement during deceleration. An object of the present invention is to provide a fuel supply control device for an internal combustion engine that can achieve both the effect and the effect of improving drivability during deceleration and the effect of preventing hunting of the engine speed after the fuel supply is restored.

[0010]

In order to achieve the above object, the invention according to claim 1 is connected with an output control means for performing a deceleration shift process for switching the speed ratio from a high speed side to a low speed side during deceleration. Fuel supply to and cutoff from the engine, and cuts off the fuel supply to the engine after a lapse of a first predetermined time from the time point when a predetermined deceleration operation condition in which the rotation speed of the engine is higher than the fuel supply cutoff judgment rotation speed is satisfied, When the predetermined fuel supply state return condition is satisfied during the cutoff state, the fuel supply cutoff state is restored to the fuel supply state to the engine, and the fuel supply cutoff is performed for a second predetermined time after the return to the fuel supply state. In a fuel supply control device for an internal combustion engine that raises a determination rotation speed by a predetermined rotation speed, when the output control means executes the deceleration shift process, the first predetermined time is shortened and And performing a reduction of the serial predetermined rotational speed.

In the fuel supply control device for the internal combustion engine according to claim 1, when the output control means executes the deceleration shift processing for switching the speed ratio from the high speed side to the low speed side during deceleration,
Since the first predetermined time from when the predetermined deceleration operation condition is satisfied until the fuel supply to the engine is cut off is shortened and the predetermined rotation speed for raising the fuel supply cutoff determination rotation speed is reduced, the fuel supply cutoff determination rotation speed is reduced. The engine rotation speed which is lifted low and increased by the increase of the gear ratio of the output control means surely exceeds the fuel supply cutoff rotation speed, and the fuel supply cutoff operation is started quickly by the reduction of the first predetermined time.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a control device for a vehicle in which a fuel supply control device for an internal combustion engine according to an embodiment of the present invention is incorporated.

In the figure, reference numeral 1 denotes an internal combustion engine (hereinafter referred to as engine), a throttle valve 3 is provided in the middle of an intake pipe 2 connected to an intake port of the engine 1, and the throttle valve 3 has a throttle. A valve opening (θTH) sensor 4 is connected. The θTH sensor 4 outputs an electric signal according to the opening degree of the throttle valve 3, and the electric signal is an electronic control signal.
Is supplied to a unit (hereinafter referred to as ECU) 5.

A fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly upstream of an intake valve (not shown) in the intake pipe 2, and each fuel injection valve 6 has a fuel pump ( Fuel is supplied from (not shown). Fuel injection valve 6
Is electrically connected to the ECU 5, and the valve opening time of each fuel injection valve 6 is controlled by a signal from the ECU 5. The valve opening time of each fuel injection valve 6 represents the fuel injection amount.

A pipe 7 is provided downstream of the throttle valve 3 of the intake pipe 2.
An absolute pressure (PBA) sensor 8 is provided via the.
The PBA sensor 8 is electrically connected to the ECU 5,
The absolute pressure PBA in the intake pipe 2 detected by the sensor 8 is converted into an electric signal and supplied to the ECU 5.

An intake air temperature (TA) sensor 9 is attached to a pipe wall downstream of the PBA sensor 8 of the intake pipe 2, and the intake air temperature TA detected by the TA sensor 9 is converted into an electric signal and supplied to the ECU 5. It

An engine water temperature (TW) sensor 10 composed of a thermistor or the like is inserted into the peripheral wall of the cylinder of the engine 1 which is filled with cooling water, and the engine water temperature (cooling water temperature) detected by the TW sensor 10 is inserted. The TW is converted into an electric signal and supplied to the ECU 5.

A rotation speed (NE) sensor 12 and a cylinder discrimination (CYL) sensor 13 are attached around a cam shaft or a crank shaft (not shown) of the engine 1. The NE sensor 12 is a half rotation of the crankshaft of the engine 1 (18
A signal pulse (hereinafter referred to as a TDC discrimination signal) is output at a predetermined crank angle position every 0 °), and the CYL sensor 1
3 outputs a signal pulse (hereinafter referred to as a CYL signal pulse) at a predetermined crank angle position of a specific cylinder. These TDC discrimination signal and CYL signal pulse are supplied to the ECU 5.

A spark plug 19 is provided in each cylinder of the engine 1. The spark plug 19 is the distributor 1.
It is electrically connected to the ECU 5 through 8, and the ignition timing by the ignition plug 19 is controlled by the ECU 5.

An exhaust pipe 14 is connected to the exhaust port of the engine 1, and HC in the exhaust gas,
A three-way catalyst 15 for purifying CO, NOx, etc. is provided.

An oxygen concentration sensor (hereinafter referred to as an O 2 sensor) 16 is provided on the exhaust pipe 14 upstream of the three-way catalyst device 15. The O2 sensor 16 outputs an electric signal according to the oxygen concentration in the exhaust gas, and the electric signal is supplied to the ECU 5.

Further, the ignition switch 25 and the starter 26 of the engine 1 are connected to the ECU 5, and the ON signal at the ON position of the ignition switch 25 and the starter signal of the starter 26 are supplied to the ECU 5.

A four-speed automatic transmission 20 is connected to the output shaft of the engine 1, and the automatic transmission 20 is provided with a control valve (CV) 21 for producing hydraulic oil for gear ratio switching. . The CV 21 is connected to the ECU 5, and the operation of the CV 21 is controlled by a signal from the ECU 5. Shift position of automatic transmission 20 (shift position)
Is detected by the shift position (PS) sensor 22, and the detection signal from the PS sensor 22 is supplied to the ECU 5. The automatic transmission 20 is provided with a vehicle speed (VP) sensor 23 for detecting the vehicle speed from the rotation speed of its output shaft.
The detection signal from 3 is supplied to the ECU 5.

The ECU 5 also receives the battery voltage VB
Is connected to a battery voltage (VB) sensor 27 and an atmospheric pressure (PA) sensor 28 that detects the atmospheric pressure PA, and the detection signal of the VB sensor 27 and the detection signal of the PA sensor 28 are supplied to the ECU 5.

The ECU 5 shapes the input signal waveforms from the various sensors described above to correct the voltage level to a predetermined level,
An input circuit 5a having a function of converting an analog signal value into a digital signal value, a central processing circuit (hereinafter, CPU)
5b, a storage means 5c for storing various calculation programs executed by the CPU 5b and calculation results, an output circuit 5d for supplying a drive signal to the fuel injection valve 6 and the ignition plug 19, and the like.

Next, the fuel supply control by the ECU 5 will be described with reference to FIG. FIG. 2 is a flowchart showing fuel supply control executed by the control device of FIG.

Referring to FIG. 2, first, in step S11, it is determined whether or not the ON signal of the ignition switch 25 is input. If it is determined that the ON signal of the ignition switch 25 is input, the process proceeds to step S12. In order to simplify the description, it is assumed that the starter 26 is driven at almost the same time as the ON signal of the ignition switch 25 to start cranking.

In step S12, the generation of the TDC discrimination signal is confirmed, and in the subsequent step S13, the signals from the respective sensors are read, and the engine from the elapsed time from the generation of the previous TDC discrimination signal to the generation of this time TDC discrimination signal The rotation speed NE of 1 is calculated.

Next, in step S14, it is determined whether or not the calculated rotational speed NE is less than or equal to the rotational speed at startup (for example, 400 rpm), and it is determined whether or not cranking is performed based on the determination result. judge.

If the cranking is determined in step S14, the process proceeds to step S17, and in step S17, the fuel injection condition for starting is calculated. Specifically, the basic fuel injection time TiCR in the starting mode set according to the engine water temperature TW is searched from the basic fuel injection table in the starting mode, and the basic fuel injection time TiC in the starting mode is searched.
R is corrected according to the rotational speed NE, and the fuel injection time TOUT is calculated by adding the invalid injection time determined from the battery voltage VB to the correction value.

On the other hand, if it is determined that the cranking is not performed in step S14, the process proceeds to step S15, and a fuel cut determination routine described later is executed. In this fuel cut determination routine, it is determined whether or not the fuel cut is to be executed according to the operating state. When the fuel cut is instructed, the flag FFC is set to "1", and when the fuel cut execution is cancelled. , Flag FFC is set to “0”.

In the following step S16, the fuel injection conditions in the basic operation mode are calculated. Specifically, the basic fuel injection time TiM set according to the rotational speed NE and the absolute pressure PBA is searched from the basic fuel injection table, and the basic fuel injection time TiM is used as various correction coefficients such as the intake air temperature correction coefficient KA. The fuel injection time TOUT is calculated by making a correction accordingly.

When the fuel injection condition in the basic operation mode or the fuel injection condition in the start mode is calculated, step S18
In step S18, it is determined whether the flag FFC is set to "1". When the flag FFC is set to "1", it is determined that the execution of the fuel cut is instructed, while when the flag FFC is set to "0", it is determined that the fuel cut release is instructed. To be done.

If it is determined that the fuel cut is instructed, the process returns to step S12, while if it is determined that the fuel cut is instructed,
Proceed to step S19.

In step S19, the injection operation of the fuel injection valve 6 is controlled based on the fuel injection condition in the basic operation mode or the fuel injection condition in the start mode, and the process is again executed in step S19.
Return to 12.

Next, the fuel cut discrimination routine of step S15 will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the fuel cut determination routine of step S15 of FIG. 2, and FIG. 4 is TFUEL used in the fuel cut determination routine.
It is a figure which shows a CUT table.

When the fuel cut determination routine is executed, first, in step S101, the opening state of the throttle valve 3 is determined as shown in FIG. Specifically, the throttle valve opening θTH is compared with the throttle valve opening θTHIDLE corresponding to the idle position, and the throttle valve opening θ
When TH is smaller than the throttle valve opening θTHIDLE, the routine proceeds to step S102, where the throttle valve opening θT
When H is equal to or greater than the throttle valve opening θTHIDLE, the process proceeds to step S110.

In step S102, the engine water temperature TW
Search the THUELCUCT table set according to the fuel cut operation determination engine speed NFCT
Is calculated.

Specifically, in the THFUELCUT table, as shown in FIG. 4, the engine water temperature TWFC
Table value NFCT0 to NFC for 4 to TWFC0
T4 is given with hysteresis, and the fuel cut operation determination engine speed NFCT is read out by searching the THFUELCUT table according to the engine water temperature TW table or calculated by the interpolation method.

Next, in step S103, the vehicle speed VP is compared with the engine speed increase determination vehicle speed VFCTH that requires the fuel cut operation determination engine speed NFCT to be increased, and the vehicle speed V is determined in step S103.
P is the fuel cut operation determination engine speed NFCT
It is determined whether or not the vehicle speed is required to lift the vehicle.

If the vehicle speed VP is equal to or higher than the engine speed increase determination vehicle speed VFCTH, it is determined that the fuel cut operation determination engine speed NFCT needs to be increased, and the process proceeds to step S104, where the vehicle speed VP is the engine speed increase determination vehicle speed. If it is lower than VFCTH, it is determined that it is not necessary to raise the fuel cut operation determination engine speed NFCT, and the process proceeds to step S107.

In step S104, it is determined whether or not the flag FTH for preventing the occurrence of hunting after releasing the fuel cut, that is, after returning to the fuel supply state is set to "1". The flag FTH is a flag that is set according to the throttle valve opening TH or the engine speed NE in step S110 or step S111 described later. When the flag FTH is set to "0", the fuel cut operation determination engine Rotational speed NFCT
Is determined to be unnecessary, and step S107 is performed.
Proceed to. On the other hand, if the flag FTH is set to "1", the process proceeds to step S105.

In step S105, the flag F described above is used.
It is determined whether FC is set to "1". If the flag FFC is set to "1", it is determined that the execution of the fuel cut is instructed, and step S10 is performed.
7, the flag FFC is set to "0",
It proceeds to step S106.

In step S106, step S102
The engine speed DNFC is added to the fuel cut operation determination engine speed NFCT calculated in
The value obtained by the addition is calculated as the fuel cut operation determination engine speed NFCT. As the lifting engine speed DNFC, a value set according to the deceleration shift process state of the automatic transmission 20 in the deceleration shift process determination process described later is used.

In the following step S107, the engine speed NE is compared with the fuel cut operation determination engine speed NFCT calculated in step S106. If it is determined that the engine speed NE is higher than the fuel cut operation determination engine speed NFCT calculated in step S106, the process proceeds to step S108, and the engine speed NE is the fuel cut operation determination engine speed calculated in step S106. If it is determined that it is equal to or less than NFCT, the process proceeds to step S111 described later.

In step S108, it is determined whether the flag FFC is set to "1". Flag FF
If C is set to "1", it is determined that the execution of fuel cut is instructed, and the process proceeds to step S109. If the flag FFC is set to "0", the process proceeds to step S113.

In step S109, the flag FFC is set to "1" to instruct the execution of the fuel cut, and the process ends.

In step S113, it is determined whether or not the fuel cut delay tmFCDLY timer has finished measuring the set time described below. If the fuel cut delay tmFCDLY timer has not finished measuring the set time, the process proceeds to step S114. , The flag FFC is set to "0" so as to cancel the operation of the fuel cut, and the processing is ended.

On the other hand, the fuel cut delay t
When the measurement of the set time by the mFCDLY timer is completed, the process proceeds to step S109, the flag FFC is set to "1" so as to instruct the operation of the fuel cut, and the process is ended.

When it is determined in step S107 that the engine speed NE is equal to or lower than the fuel cut operation determination engine speed NFCT calculated in step S106, the process proceeds to step S111, and the flag FTH is set to "1".
Set to. By setting the flag FTH to "1", the fuel cut operation determination engine speed NFCT is raised in step S106, and hunting is prevented after releasing the fuel cut, that is, after returning to the fuel supply state.

Next, in step S112, the fuel cut delay tmFCDLY timer is set to a predetermined time, and in the subsequent step S114, the flag FFC is set to "0".
To end the process. As the predetermined time set in the tmFCDLY timer in step S112,
Similar to the lift rotation speed DNFC, the timer value set according to the deceleration shift processing state of the automatic transmission 20 in the downshift determination routine is used.

When it is determined in step S101 that the throttle valve opening θTH is equal to or larger than the throttle valve opening θTHIDLE, steps S110 to S11.
4, the flag FTH is set to "0" in step S110, and tmFCDL is set in subsequent step S112.
A predetermined time is set in the Y timer, the flag FFC is set to "0" in step S114, and the process ends.

Next, the deceleration shift processing of the automatic transmission 20 will be described with reference to FIGS. 5 and 6. 5 is a flowchart showing a deceleration shift process of the automatic transmission 20 by the control device of FIG. 1, and FIG. 6 is a diagram showing a TAPOFF table used for the deceleration shift process of FIG.

During the deceleration shift process of the automatic transmission 20, FIG.
As shown in FIG. 1, first, in step S201, the vehicle speed VP is set to the deceleration shift process execution lower limit speed VSIFTD (for example, 30 km
/ H) or less, and it is determined whether or not the vehicle speed VP is in the deceleration shift processing execution region according to the determination result.

The vehicle speed VP is the lower limit speed V for executing the deceleration shift process.
If it is determined that it is less than or equal to SIFTD, step S20
2, in step S202, the accelerator-on high-speed gear duration time TAPOFF2 timer is set to the predetermined time TAPOF.
Set F2. This accelerator-on high-speed gear duration T
The APOFF2 timer is for prohibiting downshifting until the predetermined time TAPOFF2.

In the following step S203, the flag FAPOFF for permitting the time measurement operation of the accelerator pedal off duration TAPOFF timer, which will be described later, is set to "0". When this flag FAPOFF is set to "0", the time measurement operation of the accelerator pedal off duration TAPOFF timer is prohibited, and the flag FAPOFF is set to "1".
If set to, accelerator pedal off duration TAPOF
The time measurement operation of the F timer is permitted.

Then, in step S208, TAPOF
The F table is searched and the accelerator pedal off continuation time TAPOFF set according to the vehicle speed VP is set to the predetermined time TAP.
Set to OFF timer. Specifically, as shown in FIG. 6, in the TAPOFF table, the accelerator pedal off duration time TAPOFF is given to the vehicle speed VP, and the accelerator pedal off duration time TAPOFF is TA.
Read by searching the POFF table,
Alternatively, it is calculated by an interpolation method.

In the following step S209, the flag FDECSFT for controlling the execution of the deceleration shift processing is set to "0". When the flag FDECSFT is set to "0", the flag FDECSFT indicates that the execution of the deceleration shift processing has been canceled, and the flag FDECSFT set to "1" indicates that the deceleration shift processing is being executed or is being executed. Is shown. Flag FDICS
After setting FT to “0”, the subsequent processing is continuously executed.

On the other hand, in step S201, the vehicle speed VP
Is determined to be greater than the deceleration shift processing execution lower limit speed VSIFTD, the process proceeds to step S204, and the accelerator pedal opening APFZ is a predetermined value APFZ0 (for example, a fully closed value).
It is determined whether or not the following. Accelerator pedal opening AP
If it is determined that FZ is less than or equal to the predetermined value APFZ0, the process proceeds to step S210 described below, while if it is determined that the accelerator pedal opening APFZ is greater than the predetermined value APFZ0,
It proceeds to step S205.

In step S205, it is determined whether or not the actual AT shift position is at or above the shift position SFTAPOFF which permits the time measurement operation of the accelerator pedal off duration TAPOFF timer, and the actual AT shift position is at or above the shift position SFTAPOFF. Then, while proceeding to step S206, the actual AT shift position is the shift position SFTAPOF.
If it is lower than F, the processing from step S202 described above is executed.

In step S206, it is determined whether or not the time measurement by the accelerator-on high-speed gear continuation time TAPOFF2 timer is completed. If the time measurement is completed, the process proceeds to step S207 while the time measurement is completed. If not, as described above, step S2
The processing from 03 is executed.

In step S207, the flag FAPOF is set.
F is set to "1" and accelerator pedal off duration TA
Permit the time measurement operation of the POFF timer.

Next, in step S208, the accelerator pedal off duration time TAPOFF timer is set,
In the subsequent step S209, the flag FDECSFT is set to "0".
Set to. After setting the flag FDECSFT to "0", the process continues to the subsequent processes.

If it is determined in step S204 that the accelerator pedal opening APFZ is less than or equal to the predetermined value APFZ0, it is determined in step S210 whether the brake is operating. If it is determined that the brake is operating, it will be described later. While it proceeds to step S216, when it is determined that the brake is not operating, the routine proceeds to step S211.

In step S211, the flag FDECS is set.
It is determined whether FT is set to "1". When the flag FDECSFT is set to "1",
It is determined that the deceleration shift process is being performed, and step S described later is performed.
Proceed to 217. On the other hand, when the flag FDECSFT is set to "0", it is determined that the deceleration shift processing is not in progress, and the process proceeds to step S212.

In step S212, the vehicle speed VP is the vehicle speed V.
It is determined whether APOFF (for example, 50 km / h) or more. This vehicle speed VAPOFF represents the vehicle speed at which the time measurement operation of the accelerator pedal off duration timer TAPOFF is prohibited. If it is determined that the vehicle speed VP is equal to or higher than the vehicle speed VAPOFF, the process proceeds to step S213 and step S2.
In 13, the vehicle speed change amount DVSIFT is the deceleration determination deceleration D.
It is determined whether VDEC2 or less.

When it is determined that the vehicle speed change amount DVSIFT is equal to or less than the deceleration determination deceleration DVDEC2, that is, the vehicle is decelerating, the process proceeds to step S214, and in step S214, it is determined whether the flag FAPOFF is set to "1".

The flag FAPOFF is set to "1", that is, the accelerator pedal off duration time TAPOFF.
When it is judged that the time measurement operation of the timer is permitted,
In step S215, the accelerator pedal off duration time TAP
It is determined whether or not the time measurement by the OFF timer has been completed.

Accelerator pedal off duration TAPOFF
If it is determined that the timer has finished measuring the time,
Proceed to step S218, and at step S218, flag F
The DECFT is set to "1", and the processing is shifted to the subsequent processing.

It is determined in step S212 that the vehicle speed VP is lower than the vehicle speed VAPOFF, or step S2
It is determined in 13 that the vehicle speed change amount DVSIFT is greater than the deceleration determination deceleration DVDEC2, that is, the vehicle is not decelerating, or in step S214, the flag FAPOF
When it is determined that F is not set to "1", the process proceeds to step S209 via step S208 described above.

If it is determined in step S215 that the time measurement by the accelerator pedal off duration TAPOFF timer has not been completed, the process proceeds to step S209.

When it is determined in step S210 that the brake is being operated, it is determined in step S216 whether the vehicle speed change amount DVSIFT is less than or equal to the deceleration shift processing lower limit deceleration DVDEC. When it is determined that the vehicle speed change amount DVSIFT is less than or equal to the deceleration shift processing lower limit deceleration DVDEC, that is, the vehicle is decelerating, the process proceeds to step S217, and it is determined whether the flag FAPOFF is set to "1" in step S217.

When it is determined that the flag FAPOFF is set to "1", the flag FDE is set in step S218.
When CSFT is set to "1" and it is determined that the flag FAPOFF is not set to "1", the process proceeds to step S209 via step S208 described above.

In step S216, the vehicle speed change amount DV
If it is determined that SIFT is greater than the deceleration shift processing lower limit deceleration DVDEC, the process proceeds to step S211 described above,
When it is determined in step S211 that the flag FDECSFT is set to "1", the process proceeds to step S217.

Thus, during deceleration with the accelerator pedal fully closed, the vehicle speed VP and the accelerator pedal off duration TAPO
Accelerator pedal off duration T set in FF timer
Under conditions such as APOFF, vehicle speed VP, vehicle speed change amount DV
The deceleration shift processing is performed according to the SIFT and the brake operating state, and the actual fuel consumption is improved.

Next, the deceleration shift process determination process for determining whether or not the above deceleration shift process is executed is shown in FIG.
Will be described with reference to. FIG. 7 is a flowchart showing a deceleration shift process determination process by the control device of FIG.

The deceleration shift state in the automatic transmission 20 is monitored by the deceleration shift process determination process.
At the time of executing the deceleration shift process determination process, as shown in FIG.
First, in step S301, the flag FDECSFT is "1".
It is determined whether or not is set.

When it is determined that the flag FDECSFT is not set to "1", that is, the deceleration shift processing is not executed, the lifting engine speed DNFC0 is set as the lifting engine speed DNFC in step S302.
Is set, and in a succeeding step S303, a predetermined time tmFCDLY0 is set as a time to be set in the tmFCDLY timer.

On the other hand, when it is determined that the flag FDECSFT is set to "1", that is, the deceleration shift process is being executed, the lifting engine speed DNFC1 is set as the lifting engine speed DNFC in step S304, In subsequent step S305, tmF
The time set in the CDLY timer is tmF
Set CDLY1.

The lifting engine speed DNFC1 is smaller than the lifting engine speed DNFC0, and the lifting engine speed DNFC1 is equal to the predetermined time t.
mFCDLY1 is shorter than the predetermined time tmFCDLY0.

Next, the execution of fuel cut during deceleration including the execution of deceleration shift processing will be described with reference to FIG. FIG. 8 is a timing chart showing execution of fuel cut during deceleration including execution of deceleration shift processing in the control device of FIG.

Referring to FIG. 8, when the engine speed NE is higher than the fuel cut operation determination engine speed NFCT, the throttle valve 3 is closed at time t0.
The time measurement by the fuel cut delay tmFCDLY timer in which the predetermined time tmFCDLY0 is set is started. At this time point t0, the shift position of the automatic transmission 20 is assumed to be set to the fourth speed.

When the predetermined time tmFCDLY0 has elapsed,
That is, when the time measurement by the fuel cut delay tmFCDLY timer is completed, the flag FFC is set to "1".
Is set, and fuel cut is executed (steps S113 and S109 shown in FIG. 3).

Next, when the throttle valve 3 is opened at time t1, the fuel cut delay tmFCDLY timer is set to the predetermined time tmFCDLY0, the flag FFC is set to "0", and the fuel cut is released (Fig. Step S112 → S114 shown in 3).

Next, when the throttle valve 3 is closed at time t2, the relationship of NE≤NFCT is established and the flag FTH is set to "1" in the immediately preceding state. NFCT
Is lifted by the engine speed DNFC0 (steps S107, S111, S104 shown in FIG. 3,
106).

If the condition for executing the deceleration shift process in the automatic transmission 20 is satisfied at the time t3 when the fuel cut operation determination engine speed NFCT is raised, the downshift from the fourth speed to the third speed is started.

With the start of this downshift, the lift engine speed DNFC with respect to the fuel cut operation determination engine speed NFCT is set to DNFC1, and the fuel cut operation determination engine speed NFCT is set at time t.
Fuel cut operation determination engine speed N in 2
It becomes lower than FCT (step S218 shown in FIG. 5, step S301, step S304 shown in FIG. 7). Further, the fuel cut delay tmFCDLY timer is set to a predetermined time tmFCD shorter than the predetermined time tmFCDLY0.
LY1 is set (steps S301 and S305 shown in FIG. 7).

Next, when the engine speed NE increases due to the downshift operation and exceeds the fuel cut operation determination engine speed NFCT (at time t4), time measurement by the fuel cut delay tmFCDLY timer is started.

At time t5 when the predetermined time tmFCDLY1 has elapsed from time t4, the flag FFC is set to "1" and the fuel cut is executed (steps S113 and S109 shown in FIG. 3).

Immediately after the start of fuel cut (time t5
Immediately after), the shift down to the third speed is completed. The shift down is completed at this point because the shift down is performed after the time measurement by the accelerator pedal off duration TAPOFF timer is completed.

When the engine speed NE drops below the return determination engine speed NFCOFFT (at time t6) due to the execution of the fuel cut, the fuel cut delay timer tmFCDLY is set to the predetermined time tmFCDLY0 by a step not shown, and the flag F is set.
FC is set to "0" and the fuel cut is released.

As described above, during the deceleration shift process in the automatic transmission 20, the lift engine speed DNFC with respect to the fuel cut operation determination engine speed NFCT is increased.
Since T is set to DNFCT1 which is lower than DNFCT0, the engine speed NE increased by the transmission torque from the automatic transmission 20 is low and the lifting engine speed DN is low.
The fuel cut operation determination engine speed NFCT raised by one FCT is exceeded in a short time in a reliable manner, and the fuel cut can be reliably performed.

Also, fuel cut delay tmFC
Since the predetermined time tmFCDLY1 shorter than the predetermined time tmFCDLY0 is set in the DLY timer, the engine speed NE is the fuel cut operation determination engine speed NFC.
It is possible to shorten the period from the time when T is exceeded to the start of execution of fuel cut, and it is possible to improve fuel efficiency.

As described above, it is possible to achieve both the sufficient fuel efficiency improvement effect during deceleration by the deceleration shift processing, the drivability improvement effect during deceleration, and the engine speed hunting occurrence prevention effect.

[0096]

As described above, according to the fuel supply control device for an internal combustion engine according to the first aspect, when the output control means is executing the deceleration shift process, the engine is started from the time when the predetermined deceleration operation condition is satisfied. Since the first predetermined time until the fuel supply to the engine is cut off and the predetermined number of rotations for raising the fuel supply cutoff determination rotation speed are reduced, the fuel supply cutoff determination rotation speed is raised to a low level, and the output control means of the output control means. The engine rotation speed increased by the increase of the gear ratio surely exceeds the fuel supply cutoff determination rotation speed, and the fuel supply cutoff operation is started quickly by shortening the first predetermined time, and the fuel supply cutoff is performed by the deceleration shift process by the output control means. There is no fear that smooth execution of the engine will be hindered, and there will be sufficient fuel efficiency improvement effects during deceleration, drivability improvement effects during deceleration, and engine speed after fuel supply is restored. It is possible to achieve both the effect of preventing the number of hunting.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a control device for a vehicle in which a fuel supply control device for an internal combustion engine according to an embodiment of the present invention is incorporated.

FIG. 2 is a flow chart showing fuel supply control executed by the control device of FIG.

FIG. 3 is a flowchart showing a fuel cut determination routine in step S15 of FIG.

FIG. 4 is a T used in a fuel cut determination routine.
It is a figure which shows a HFULCUT table.

5 is a flowchart showing a deceleration shift process of the automatic transmission 20 by the control device of FIG.

6 is a TAPOF used in the deceleration shift process of FIG.
It is a figure which shows an F table.

7 is a flowchart showing a deceleration shift process determination process by the control device of FIG.

8 is a timing chart showing execution of fuel cut during deceleration including execution of deceleration shift processing in the control device of FIG. 1. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 engine (internal combustion engine) 5 ECU (fuel supply control device) 6 fuel injection valve 9 intake air temperature sensor 10 engine water temperature sensor 12 NE sensor 20 automatic transmission 21 CV (control valve) 22 PS sensor 23 VP sensor 27 battery voltage sensor 28 PA sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F16H 63:40 (72) Inventor Kenichiro Ishii 1-4-1 Chuo Wako-shi, Saitama Stock company Honda R & D Center

Claims (1)

[Claims] 1. A fuel supply to and a cutoff of an internal combustion engine to which an output control means for performing a deceleration shift process for switching a gear ratio from a high speed side to a low speed side at the time of deceleration is connected, and the rotational speed of the engine is fueled. The fuel supply to the engine is cut off after a lapse of a first predetermined time from the time when a predetermined deceleration operation condition higher than the cutoff determination rotation speed is satisfied, and the predetermined fuel supply state return condition is satisfied during the fuel supply cutoff state, the fuel supply cutoff is performed. In a fuel supply control device for an internal combustion engine, the fuel supply control device returns the fuel supply state to the engine from a state, and raises the fuel supply cutoff determination rotation speed by a predetermined rotation speed for a second predetermined time from the time of returning to the fuel supply state, When the deceleration shift process is executed by the output control means, the first predetermined time is shortened and the predetermined number of revolutions is decreased. The control device.