JPS63113138A - Fuel supply control device for car-mounted internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the hunting of engine speed from occurring as well as to improve drivability, by stopping a fuel cut even if a fuel cut condition is materialized as long as the stopping time to be set by an engine running parameter, when resuming the supply of fuel from its cut. CONSTITUTION:A vacuum switch 21 to be turned on when a throttle valve 2 less than the specified opening, a suction absolute pressure sensor 24, a crank angle sensor 25, a water temperature sensor 26, a car speed sensor 27, a clutch switch to the turned on at the time of clutch operating and a current sensor 29 detecting a current flowing in a current consumer are all connected to a control circuit 30. This circuit 30 judges a decelerated state on the basis of each detected value out of these sensors, and it perform a fuel cut via a fuel-cut solenoid valve 15. During the fuel cut, if a clutch is opened, this fuel cut is stopped, and the throttle valve 2 is opened as long as the specified time via a three-way solenoid valve 6 and a throttle opener 3, but even if the clutch is engaged again, the fuel cut is stopped as long as the stopping time that is set as the longer, the higher in engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for a vehicle-mounted internal combustion engine, and more particularly to a fuel supply device having a fuel cut function.

1. When an internal combustion engine is decelerating, the throttle valve closes and the negative pressure in the intake pipe downstream of the throttle valve rises rapidly, so that the fuel adhering to the inner wall of the intake pipe and the fuel from the low-speed system of the carburetor are absorbed into the engine. supplied to For this reason, during deceleration, the air-fuel ratio of the air-fuel mixture supplied to the engine becomes overrich, resulting in an increase in unburned harmful components in the exhaust gas. Conventionally, in order to prevent the air-fuel ratio from overriching during deceleration and to save fuel, fuel supply was stopped when the angular pressure inside the intake pipe became large, and when the clutch was released or the transmission was in the neutral state. A device for restarting fuel supply when the fuel is turned off is disclosed in Japanese Utility Model Publication No. 56-53071. However, depending on the type of operation, the clutch may be released and re-engaged before the engine speed has fallen sufficiently after deceleration operation has started, or the transmission may be operated to the neutral position and then shifted into gear again. In such cases, with conventional systems, the fuel supply is stopped immediately after the fuel supply is restarted from the fuel supply stop, resulting in the problem of engine rotational speed hunting and deterioration of drivability. there were.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel supply control device for an on-vehicle internal combustion engine that prevents deterioration of drivability when the fuel supply is required to be stopped immediately after restarting the fuel supply. It is.

The fuel supply control device of the invention of Application No. 1 stops the fuel supply to the engine when an operating condition in which the fuel supply should be stopped is detected, and then stops the fuel supply to the engine when an operating condition in which the fuel supply should be restarted is detected. It has a fuel cut means for restarting the fuel supply to the engine, and prevents the operation of the fuel cut means for a blocking time from the time when the fuel supply is restarted, and the blocking time is set according to the value of a predetermined operating parameter of the engine. It is characterized by setting. Further, the fuel supply control device of the invention of Application No. 2 stops the fuel supply to the engine when an operating condition in which the fuel supply should be stopped is detected, and thereafter, when an operating condition in which the fuel supply should be restarted is detected. and a fuel cut means for restarting the fuel supply to the engine, the operation of the fuel cut means is prevented for a blocking time from the time when the fuel supply is restarted, and the blocking time is depending on the value of a predetermined operating parameter of the engine. The present invention is characterized in that the throttle valve opening degree is increased by the throttle valve opening degree control means within the blocking time from the time when the operating state in which the fuel supply should be resumed is detected.

Friend-Jul Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows an on-vehicle internal combustion engine equipped with a fuel supply control device according to an embodiment of the present invention.

In this figure, a throttle valve 2 of a carburetor 1 opens in conjunction with an accelerator pedal (not shown), and a diaphragm 3
It is driven by a throttle opener 3 having a.

The diaphragm 3a of the throttle opener 3 and the throttle valve 2 are connected by a rod 3b so as to be interlocked.

The throttle opener 3 has a pressure receiving chamber 3C in which a diaphragm 3a forms a part, and a spring 3 is disposed within the pressure receiving chamber 3C.
d, the diaphragm 3a is urged outward, that is, the throttle valve 2 is urged to close.

Further, the pressure receiving chamber 3C communicates with the intake pipe 5 downstream of the throttle valve via the negative pressure supply passage 4.

A three-way solenoid valve 6 is provided in the negative pressure supply passage 4, and the solenoid valve 6
When the solenoid 6a is not energized, the intake pipe 5 side of the negative pressure supply passage 4 is closed and atmospheric pressure is supplied to the pressure receiving chamber 3C side of the negative pressure supply passage 4 through the filter 7, and current is supplied to the solenoid 6a. When excited, the negative pressure supply passage 4 is brought into communication and the supply of atmospheric pressure is stopped.

A slow boat 11 and an idle boat 12 for a low speed system are formed on the inner wall surface of the carburetor 1 near the throttle valve 2. The slow boat 11 and the idle boat 12 communicate with a slow fuel supply passage IB13, and the slow fuel supply passage 13 is provided with a fuel cut solenoid valve 15. The fuel cut solenoid valve 15 connects the slow fuel supply passage 13 when the solenoid (not shown) is not energized, and closes the slow fuel supply passage 13 when the solenoid is energized. The fuel discharged from the idle boat 12 is adjusted by the idle adjustment screw 16.

Further, a negative pressure detection boat 19 is provided on the inner wall surface of the carburetor 1 near the throttle valve 2. The negative pressure detection boat 19 is the throttle valve 2
is located upstream of the throttle valve 2 when the opening degree is less than or equal to a predetermined opening degree of 61,
The throttle valve 2 is located downstream of the throttle valve 2 when the opening degree is larger than the predetermined opening θ1. Negative pressure in the negative pressure detection boat 19 is supplied to a negative pressure switch 21 via a negative pressure passage 20.

The negative pressure switch 21 is provided to detect the closed state of the throttle valve 3, and is turned on when the negative pressure in the negative pressure detection boat 19 is, for example, 3 Q ma + I1g or less.

On the other hand, 24 is an absolute pressure sensor installed in the intake pipe 5 and generates an output at a level corresponding to the absolute pressure inside the intake pipe 5, and 25 generates a pulse according to the rotation of the crankshaft (not shown) of the engine 9. The crank angle sensor 26 is a coolant temperature sensor that generates an output at a level corresponding to the coolant temperature of the engine 9.

Solenoid valve 6.15, negative pressure switch 21, absolute pressure sensor 24
, the crank angle sensor 25, and the water temperature sensor 26 are connected to the control circuit 3.
Connected to 0. The control circuit 30 further includes a vehicle speed sensor 27 that generates an output at a level corresponding to the speed of the vehicle, a clutch switch 28 that is linked to a clutch pedal (not shown) and turns on when the clutch pedal is depressed, headlights, and an air conditioner. A current sensor 29 consisting of a resistor is connected to detect the load 'R current to an electrical load such as the like as a voltage. The negative pressure switch 21 and clutch switch 28 generate a low level output when turned off, and generate a high level output V when turned on.
e is generated.

The control circuit 30 includes an absolute pressure sensor 24, as shown in FIG.
A level conversion circuit 31 that converts each output level of the water temperature sensor 26, vehicle speed sensor 27, and current sensor 29; a multiplexer 32 that selectively outputs one of the sensor outputs that have passed through the level conversion circuit 31; The A/D converter 33 converts the output signal into a digital signal, the waveform shaping circuit 34 shapes the output signal of the crank angle sensor 25, and the generation interval of the TDC signal output as a pulse from the waveform shaping circuit 34. a counter 35 that measures the number of output pulses output from a clock pulse generation circuit (not shown); and a negative pressure switch 2.
1 and the clutch switch 28, a digital input camosulator 37 that converts each switch output via the level conversion circuit 36 into digital data, and a drive circuit 38a that drives the solenoid valve 6.
, a drive circuit 38b that drives the fuel cut solenoid valve 15, and a CPU that performs digital calculations according to the program.
(central processing circuit) 39, a ROM 40 in which various processing programs and data are written in advance, and a RAM 41. Multiplexer 32, A/D converter 33
, counter 35, digital input camosulator 37, drive circuits 38a, 38b, CPLJ 39, ROM 40 and RAM 41 are connected to each other by an input/output bus 42.

The CPU 39 also has timers TA and TB (not shown).

In such a configuration, the information representing the absolute pressure in the intake pipe 4, the cooling water temperature, the vehicle speed, and the load current is alternatively transmitted from the A/[) converter 33, and the information representing the engine speed is alternatively transmitted from the counter 35, and the information representing the engine speed is also transmitted digitally. The on/off information of the negative pressure switch 21 and clutch switch 28 is transmitted from the input camosulator 37 to C.
Each is supplied to the PU 39 via an input/output bus 42. C
The PLJ 39 executes a fuel cut control routine, which will be described later, every predetermined period T1 to generate a fuel cut command or a fuel cut stop command to the drive circuit 38b, and also issues an idle up command or an idle up stop command to the drive circuit 3.
Occurs for 8a. The drive circuit 38a drives the solenoid valve 6 by supplying current to the solenoid 6a of the solenoid valve 6 in response to the idle-up command to connect the negative pressure supply passage 4, and the solenoid 6 in response to the idle-up stop command.
The current supply to a is stopped and atmospheric pressure is supplied to the negative pressure supply passage 4 on the pressure receiving chamber 3C side. Further, the drive circuit 38b drives the fuel cut solenoid valve 15 to close the slow fuel supply passage 13 in response to the fuel cut command, and stops driving the fuel cut solenoid valve 15 to supply slow fuel in response to the fuel cut stop command. The passage 13 is communicated.

Next, the operation of the fuel supply control device according to the present invention will be explained in detail according to the fuel cut control routine shown in FIG.

In the fuel cut control routine, the CPU 39
As shown in the figure, first, the engine rotational speed Ne is read and it is determined whether or not the engine rotational speed Ne is greater than a predetermined rotational speed Ne+ (for example, 1800r, p, s) (step 51). When Ne≦Ne1, it is determined whether the fuel cut determination flag FCUT is equal to 1 (
Step 52).

Since the fuel cut determination flag FCLIT is initialized to 0 at the same time as the ignition switch (not shown) is turned on, the determination result in step 52 immediately after the ignition switch is turned on is Fc LJ T -0.

If Fc LI T-0, it is not the operating state that requires fuel cut, so timer TA is set for a predetermined time TA (f!III
For example, 0.3 sec) is set to start the down 4 measurement (step 53), the flag FCLJT is reset to O (step 54), and a fuel cut stop command is issued to the drive circuit 38b (step 55). . Ne＞
When Ne1, the vehicle speed VH is read and it is determined whether or not the vehicle speed VH is greater than a predetermined speed V)II (for example, 1/h in 15). If VH≦MHI, the vehicle speed V)4 is determined. Since it is low, step 52 is executed. V
If l-1>VH+, and if it is determined as FCUT-1 at step 52 because fuel cut is being performed, the read engine speed Ne is equal to the predetermined speed Ne2 (
Ne'2<Net, e.g. 1300r, l), 11
) J: Determine whether or not it is large (step 57
).

In the case of Ne>Ne2, it is determined whether the read vehicle speed V)4 is greater than a predetermined speed VH2 (Vl-12<Vl-11, e.g. Eva, 12/h), step 58);
If VH>VH2, it is determined whether the negative pressure switch 21 is on or not from the on/off information of the negative pressure switch 21 (
Step 59). When the negative pressure switch 21 is on, the throttle valve 2 is closed and the engine is in a deceleration state, so it is an operating state in which fuel should be cut, and whether or not the clutch switch 28 is on is determined from the on/off information of the clutch switch 28. (step 60). If the clutch switch 28 is off, the clutch is engaged, so timer TA's measurement II
It is determined whether TNTH has reached O (step 61). TXT) In the case of I>O, since the predetermined time TA has not passed since the fuel cut condition was satisfied, steps 54 and 55 are executed to generate a fuel cut stop command. TXT) If I = 0, the predetermined time T^ has passed since the fuel cut condition was satisfied, so 1 is applied to the 7-lag FCUT.
(step 62), and generates a fuel cut command (step 63).

On the other hand, when Ne≦N e x , V H≦VH2, or the negative pressure switch 21 is off, it is a driving state in which fuel should not be cut. ΔV(=VH−V
ΔV+ (
For example, -4.0 m/h/sec), it is determined whether or not the time is small (step 64). If Δ■≧Δ■1, it is assumed that the vehicle is not decelerating and steps 53, 54, and 55 are executed so as not to cut fuel.

On the other hand, if Δ■<Δ■1, it is determined that deceleration is in progress and it is determined whether the flag FCUT is equal to 1 (step 65
). When Fc LJ T =O, fuel cut is not currently being performed, so steps 54 and 55 are executed so as not to cut fuel even during deceleration. Fc u v =
1, the fuel cut is currently being performed, so the fuel cut prevention time T+ corresponding to the read engine speed Ne is searched from the first data table, and the idle up time T+ corresponding to the engine speed Ne is searched from the first data table. 2 data table (step 65). For example, the engine speed N is stored in the ROM 40 with the characteristics shown in Fig. 4.
Since the blocking time TI and idle up time T2 for e are written in the first and second data tables in advance, the CPLJ39 sets the blocking time T1 and idle up time T2 corresponding to the read engine speed Ne to the first and second data tables. Search from the second data table. After searching for times T+ and T2, timer TAk: blocking time T+ is set to start down measurement (step 67), and timer TB is set to idle up time T2 to start down measurement (
Step 68) and execute steps 54 and 55 to stop the fuel cut. Further, if it is determined in step 60 that the clutch switch 28 is on because the clutch pedal has been depressed, step 65 is executed because the power transmission system has been cut off.

After the fuel cut stop command is generated by executing step 55 or after the fuel cut command is generated by executing step 63, the load current IL is read and the load current I
It is determined whether L is larger than a predetermined current ILI (for example, ' 6 A) (step 69). IL > I
In the case of L+, an idle up command is generated to the drive circuit 38a to promote charging of the battery 43 (step 70). If IL≦ILI, it is determined whether the measured value Tau of the timer TB has reached O or not (Step 71); if Ttu>0, an idle up command is generated (Step 70); if Tru -0; For example, an idle up stop command is generated (step 72).

The drive circuit 38b drives the fuel cut electromagnetic valve 15 in response to the fuel cut command to open the slow fuel supply passage 13 to lWiM.
let As a result, fuel is no longer supplied to the slow boat 11 and the idle boat 12, resulting in a fuel cut state. In response to the fuel cut stop command in this fuel cut state, the drive circuit 38b stops driving the fuel cut electromagnetic valve 15, so that the slow fuel supply passage 13 is communicated and fuel is discharged from the slow boat 11 and the idle boat 12.

Since the drive circuit 38a does not drive the three-way solenoid valve 6 in response to the idle-up stop command, the intake pipe 5 side of the negative pressure supply passage 4 is closed, and atmospheric pressure is supplied to the pressure receiving chamber 3C side of the negative pressure supply passage 4. The pressure inside the pressure receiving chamber 3C is made equal to atmospheric pressure. As a result, the force of the spring 3d causes the throttle valve 2 to
is in an open state. Further, the drive circuit 38a drives the three-way solenoid valve 6 in response to the idle-up command, and the negative pressure supply passage 4
Since the supply of atmospheric pressure is stopped and the negative pressure supply passage 4 is opened for communication, the negative pressure in the intake pipe 5 is supplied to the pressure receiving chamber 3c of the throttle opener 3 via the negative pressure supply passage 4. Since this supplied negative pressure becomes greater than the biasing force of the spring 3d, the diaphragm 3a is attracted toward the pressure receiving chamber 3C and reversed, and in conjunction with this, the throttle valve 2 opens by a predetermined opening degree θ2. By opening the throttle valve 2, the amount of air-fuel mixture supplied from the carburetor 1 to the engine increases, and the engine speed, ie, the idle speed, increases.

In the fuel supply control Iff according to the present invention, N
e > N e 2 , V H > V H2, when the fuel cut conditions that the negative pressure switch 21 is on and the clutch switch is off are satisfied, the slow fuel supply passage 13 is usually closed after a predetermined time TA has elapsed. fuel cut is started. After starting fuel cut, Ne
>Nez, VH>Vl-12, when the negative pressure switch 21 is on and the clutch is released and the clutch switch is turned on, fuel cut is stopped and fuel supply is restarted, and the throttle is kept until time T2 has elapsed. The opening degree of the valve 2 is increased to increase the engine speed Ne. Immediately after the fuel supply is restarted, if the clutch is engaged again and the fuel cut condition is satisfied, the fuel will not be refilled until the blocking time T + corresponding to the engine speed N8 has elapsed since the fuel supply restarted. The cut is blocked, blocking time T
The fuel cut is performed after one elapse, and the time from when the fuel cut conditions are satisfied until the fuel cut is actually performed is longer than usual. Further, the blocking time T's idle-up time T2 becomes longer as the engine speed Ne becomes higher.

Also, after the start of fuel cut, Ne≦Ne2, VH≦V)4
2% or when the negative pressure switch 21 is turned off and the fuel cut conditions are no longer satisfied, the fuel cut is stopped and fuel supply is restarted. Also, if ΔV≧Δv1 then,
Since the amount of deceleration change in vehicle speed VH per unit time is small, if the fuel cut condition is satisfied again, fuel cut is performed after the predetermined time TA has elapsed. On the other hand, if Δv - ΔV+, the amount of deceleration change per unit time in the vehicle speed V)4 is large, so the opening degree of the throttle valve 2 is increased until the time T2 has elapsed from the restart of fuel supply, as described above, and the engine rotation When the fuel cut condition is met again by increasing the engine speed Ne, the blocking time T1 is set according to the next engine speed Ne.
The fuel cut is performed after a period of time from the time when the fuel supply is restarted.

Note that the timers TA to T8 include, for example, down counters that measure time by measuring clock pulses. Further, if the above routine is executed at predetermined time intervals, the predetermined time periods T+ and Tz may be measured by performing a counting operation within the program.

In the fuel supply m device of the present invention, the blocking time from detecting the deceleration driving state in which fuel supply should be stopped until actually stopping the fuel supply is determined by the engine speed, etc. Since the engine speed changes depending on the operating parameters, even if the clutch is released and then re-engaged before the engine speed has fallen sufficiently after deceleration operation has started, the fuel supply will not restart from the fuel supply stop. After that, the fuel supply is prevented from being immediately stopped. Therefore, hunting when the fuel supply should be stopped immediately after restarting the fuel supply is prevented, and drivability can be improved.

Furthermore, by increasing the opening degree of the throttle valve after resuming fuel supply, the engine speed can be stabilized, and drivability can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a specific configuration of a control circuit in the device shown in FIG. 1, FIG. 3 is a flow diagram showing the operation of the CPU, and FIG. FIG. 4 is a diagram showing the engine rotation speed Ne-time TINT2 characteristic. Explanation of symbols of main parts 1... Carburizer 2... Throttle valve 5... Intake pipe 6... 3-way solenoid valve 11... - Slow boat 12... Idle boat 13... Slow fuel supply passage 15... Fuel cut solenoid valve 21... Negative pressure switch

Claims (5)

[Claims] (1) A detection means for detecting an operating state in which the fuel supply to the in-vehicle internal combustion engine should be stopped; and when the detection means detects an operating state in which the fuel supply should be stopped, the fuel supply to the engine is stopped; , fuel cut means for restarting fuel supply to the engine when the detection means detects an operating state in which fuel supply should be restarted;
and blocking means for blocking the operation of the fuel cut means for a blocking time from the time when fuel supply is resumed, and the blocking means sets the blocking time in accordance with the value of a predetermined operating parameter of the engine. Fuel supply control device. (2) The fuel supply control device according to claim 1, wherein the blocking means sets a blocking time depending on the engine rotation speed. (3) The fuel supply control device according to claim 1, wherein the blocking means sets a longer blocking time as the engine speed increases. (4) a detection means for detecting an operating state in which the fuel supply to the in-vehicle internal combustion engine should be stopped; and when the detection means detects an operating state in which the fuel supply should be stopped, the fuel supply to the engine is stopped; , fuel cut means for restarting fuel supply to the engine when the detection means detects an operating state in which fuel supply should be restarted;
blocking means for blocking the operation of the fuel cut means for a blocking time from the time when fuel supply is restarted; and blocking means for opening the throttle valve within the blocking time from the time when the detecting means detects an operating state in which fuel supply should be resumed. a throttle valve opening control means for increasing the throttle valve opening degree, and the blocking means sets the blocking time in accordance with a value of a predetermined operating parameter of the engine. (5) The fuel supply control device according to claim 4, wherein the throttle valve opening degree control means increases the throttle valve opening degree for a time shorter than the blocking time.