JPH0357293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a throttle opening control method when fuel is cut during engine deceleration.

(Prior art) Conventionally, during deceleration and racing, combustion becomes incomplete and HC increases, so as a countermeasure to prevent this, the dart pot method is used to slow down the return of the throttle valve during deceleration, or the A throttle positioner method is used to control the throttle valve opening during deceleration, which opens the valve slightly from the opening at idling.
In this case, the return speed and degree of opening of the throttle valve during deceleration must be determined depending on various engine characteristics, etc., and the number of control actuators increases.For example, the diaphragm of the actuator changes over time. Therefore, there was a drawback that the control characteristics of the valve opening degree changed.

As a countermeasure for this problem, for example, as described in Japanese Patent Application Laid-Open No. 59-37238, when the engine is running at deceleration, the throttle opening is gradually adjusted by dart pot control according to a preset deceleration rate corresponding to the engine characteristics. This effectively prevents abnormal HC emissions by controlling the idle opening to stabilize the deceleration characteristics of the engine, but in this case, the fuel consumption characteristics of the engine are affected because the fuel is not cut during deceleration. There was a drawback that it did not improve.

Therefore, in recent years, a method has been adopted to prevent abnormal HC emissions while improving fuel efficiency by cutting fuel or restricting fuel during deceleration.In this case, fuel cutting is continued until low speed rotation. Although this has a great deceleration effect, when the engine returns to neutral and the fuel is restored, the delay in fuel return can easily cause the engine to stall, so it is important to reduce the throttle opening during deceleration to the extent that the engine does not stall. When controlled, the drawback was that an unpleasant car shock was likely to occur when the fuel was restored with the gear engaged.

(Problems to be Solved by the Invention) The present invention increases the deceleration effect by cutting fuel when the engine decelerates, prevents abnormal HC emissions, and improves the fuel economy characteristics of the engine. The objective is to obtain smooth and stable engine deceleration characteristics that do not cause problems with car shock.

(Means for Solving the Problems) As shown in FIG.
It is determined whether the throttle lever has contacted the motor-driven throttle actuator or not, and when the throttle lever is in contact with the throttle actuator and the engine is decelerating, the engine speed is decelerated in step S02. It is determined whether or not the rotation speed is above NE1, which is a predetermined rotation speed that requires control, and when it is above NE1, the fuel passage in the carburetor is shut off in step S03, and the throttle opening is changed to the throttle actuator in step S04. By operating the yuator, in the early stage of fuel recovery, the engine is controlled to a high engine speed recovery opening Tθ1 that is larger than the idle opening Tθ0 that can secure the fuel amount to maintain a relatively high engine rotation during deceleration control. It is determined whether or not the vehicle drive by the engine is released at a high rotation speed before the rotation speed reaches a predetermined rotation speed NE2 that does not require deceleration control, and the vehicle drive by the engine is stopped before the rotation speed reaches the predetermined rotation speed NE2. When it is released, the fuel passage is opened in step S06, and the throttle opening is changed to the throttle actuator after an elapse of T1 time for the fuel to pass through the entire fuel passage after the fuel is restored in step S07. The idle opening degree Tθ0 is controlled by the operation of the motor, and the step S
In step S08, it is determined whether or not the engine speed has become below the predetermined speed NE2, and when the engine speed has become below the predetermined speed NE2, the fuel passage is opened in step S09, and the throttle opening degree is adjusted in step S10. Through the operation of the throttle actuator, the idle opening that can secure the amount of fuel required to maintain a relatively low engine speed without requiring deceleration control in the early stage of fuel return is set to an opening at low rotation return that is slightly larger than Tθ0. The throttle opening is controlled to Tθ2 and the throttle opening is adjusted to the idle opening Tθ0 by operating the throttle actuator after an elapse of T1 time for the fuel to pass through the entire fuel passage after the fuel is restored in step S07. A method for controlling the deceleration time opening of a throttle valve to be controlled.

(Embodiment) Next, the configuration of an embodiment of the present invention will be explained with reference to FIGS. 2 to 5.

A throttle valve 4, which opens in response to the amount of depression of the accelerator pedal, is attached to an intake passage 3 that supplies fuel from the carburetor 2 to the engine, and is biased in the valve closing direction by a spring (not shown). When the valve 4 is in the closed position, the throttle lever 6 fixed to the shaft 5 of the throttle valve 4 is connected to an actuator (ISC) 7, in this case, a threaded rod 10 via a reversible DC motor 8 and a gear train 9.
The actuator 7 is determined by contacting the touch head 12 at the tip of the actuator 7, which rotates forward and backward to move the output shaft 11, which is fitted with a screw to a threaded rod 10 whose circumferential movement is restricted, back and forth, and the slot relative to the touch head 12. The contact of the tuttle lever 6 resists the biasing force of the spring 13, and the output shaft 1
The end of the stroke of the output shaft 11 is detected when the idle switch 15 is turned on due to the final gear 14 slightly retracting with the final gear 1, and the end of the stroke of the output shaft 11 is detected when the dog 16 on the output shaft 11 comes into contact with the lever 18 of the limit switch 17. Detected.

This carburetor 2 includes a main cut solenoid valve 22 for cutting off the fuel supply to the main nozzle 20 formed in the small bench lily 19 of the intake passage 3 at the main jet 21 position, and a main cut solenoid valve 22 formed near the throttle valve 4 of the intake passage 3. slow port 2
3, and an air bleed control valve 25 for adjusting bleed air for the main and slow systems. The needle valve 2 together with the threaded rod 28 whose directional movement is restricted.
an air bleed control valve 25 that adjusts the amount of bleed air supplied from the air hole 30 to the main system and slow system fuel passages 33, 34 through the air passages 31, 32 by moving the valve 9 back and forth; , an auxiliary fuel pump 35 that increases the amount of fuel supplied to the engine during engine startup, acceleration, etc.; in this case, a solenoid coil 36;
The reciprocating motion of the piston 39 via the plunger 38 due to the on/off operation of the valve and the biasing force of the spring 37 allows the fuel from the float chamber 40 of the carburetor 2 to pass through the suction side check valve 41 and once into the cylinder chamber 42. An auxiliary fuel pump 35 is installed to supply fuel from the discharge side check valve 43 to the intake passage 3 through an auxiliary nozzle 45 formed above the large bench lily 44.

In the carburetor 2 configured in this way, the DC motor 8 of the actuator 7, each switch 15,
17, each electromagnetic valve 22, 24 for fuel cut, the stepper motor 26 of the air bleed control valve 25, the solenoid coil 36 of the auxiliary fuel pump 35, and the valve that is attached to the carburetor 2 and corresponds to the opening degree of the throttle valve 4. A throttle opening sensor 46 that generates the output, a water temperature sensor 47 attached to the engine water jacket, and an engine rotation speed centimeter 48 such as an ignition coil.
, a vehicle speed sensor 49 that generates an output corresponding to the speed of the vehicle, and an O ₂ sensor 50 that is attached to the exhaust passage and generates an output that corresponds to the oxygen concentration.
Clutch/neutral detection sensor 5 that changes the output when the clutch is off and in neutral state
1, a side lamp switch 52 that generates an output when the side lamp is turned on, and an economy/diagnosis lamp 53 that lights up when the economy/diagnosis is performed.
, the air conditioner switch 54 , the starter switch 55 , the ignition key switch 56 , and the alternator control circuit 57 , whose power supply from the battery 58 is controlled on and off by the ignition key switch 56 . common name
It is connected to the engine control electric control circuit 59 of the ECU.

Next, FIG. 3 shows a specific example of the electric control circuit 59, in which the microcomputer CPU, which is controlled according to the program in the memory circuit ROM, receives the engine speed signal from the engine rotation speed sensor 48 via the waveform shaper 60. In addition to inputting a pulse signal with a frequency corresponding to the rotational speed, an analog signal corresponding to the engine cooling water temperature from the water temperature sensor 47 and an analog signal corresponding to the opening degree of the throttle valve 4 from the throttle opening sensor 46 are input. The analog signal corresponding to the oxygen concentration from the O ₂ sensor 50 is inputted via the input port 62 after being converted into a digital signal via the A/D converter 61.
In addition, the idle switch 15, the clutch/neutral detection switch 51, and the air conditioner switch 54
and pulse output from the vehicle speed sensor 49, ignition key switch 56, starter switch 55, and side lamp switch 52, respectively.
An off signal is input via the input port 63,
Also, the output port 6 of the microcomputer CPU
4, the DC motor 8 of the actuator 7, the solenoid coil 36 of the auxiliary fuel pump 35, and the main cut electromagnetic valve 22 are connected via each drive circuit 65 to 69.
In addition, the output port 70 is connected to the stepper motor 26 of the air bleed control valve 25 via the drive circuit 71.
is connected.

Next, the operation of this embodiment will be explained.

In an engine control device configured in this way, in particular an engine control device for an electronically controlled chokeless carburetor, a microcomputer is used.
The CPU is set with a target idle opening Tθ0 and a target idle rotation speed NE0, which change depending on the engine cooling water temperature, as well as an engine rotation speed NE1 that requires preset deceleration control, and a preset deceleration control. Engine speed NE2 that does not require
and a throttle opening at high rotational speed return Tθ1 that is larger than the idle opening that can secure the amount of fuel necessary to maintain a relatively high engine rotation during deceleration control in the early stage of fuel return, and that deceleration control is not required in the early stage of fuel return. A low rotation return time degree Tθ2 that is slightly larger than the idle opening degree Tθ0 that can secure the amount of fuel necessary to maintain a relatively low engine rotation, and a fuel passage time that corresponds to the time when fuel passes through the entire fuel passages 33 and 34 after fuel return. T1 and each are set,
During deceleration in this setting state, the engine is controlled according to the flowchart shown in FIG. 5, which will first be explained using the operation diagram shown in FIG. 4.

Now, the output signal of idle switch 15 is OFF.
In other words, when the engine is not in the idling state and the output signal of the neutral state detection switch 51 is OFF, in other words, the engine is not in the neutral state and the vehicle is being driven by the engine, the engine and rotational speed NE are at the throttle level when the engine is decelerating. When the idle switch 15 is turned on when the engine speed is higher than a relatively high predetermined engine speed NE1 set in advance to execute the opening control,
In this state, the engine enters deceleration operation, the throttle opening Tθ is closed to the idle opening Tθ0, and the electric control circuit 59 controls each fuel passage 33,
The main cut solenoid valve 22 for cutting off the fuel supply to the main jet 21 is activated.

Next, the throttle opening Tθ is set to a high rotation return opening that can secure the amount of fuel necessary to maintain a relatively high engine rotation during deceleration control in the early stage of fuel return, and is larger than the idle opening Tθ0. The opening degree is controlled to Tθ1. As a result of decelerating the engine while consuming the fuel remaining in the fuel passages 33 and 34 of the carburetor 2 while controlling the throttle opening Tθ to an opening Tθ1, the output signal of the engine rotation speed detection sensor 48 causes Engine speed NE
However, when it is determined that the rotation speed has decreased to NE2 which does not require deceleration control to release the fuel cut, the fuel supply is restarted (F/C: OFF).

The throttle opening is maintained from the time when the fuel supply is resumed until the time set in accordance with the transient characteristics of the engine, that is, the fuel passage time T1 corresponding to the time when fuel passes through the entire fuel passages 33 and 34 after fuel return.
Tθ is a low rotation return opening that can secure the amount of fuel necessary to maintain a relatively low engine speed without requiring deceleration control in the early stage of fuel return, and is a low rotation return opening that is slightly larger than the idle opening Tθ0. Degree Tθ
2, and after the set time T1 has elapsed, the throttle opening degree Tθ is controlled to return to the idle opening degree Tθ0 to prevent engine failure when the fuel is restored, and to prevent unpleasant car shock by setting the throttle opening degree appropriately when the fuel is restored. prevent.

On the other hand, as shown in FIG. 4B, as in FIG. 4A, the engine and operating state are neither in the idle state (idle switch 150FF) nor in the neutral state (neutral switch 510FF).
When the engine speed NE is higher than the relatively high predetermined engine speed NE1 that requires deceleration control when the vehicle is being driven by the engine, when the idle switch 15 is turned on, the engine enters deceleration operation in this state. , throttle opening Tθ
is closed to the idle opening Tθ0, and
Electric control circuit 59 operates main cut solenoid valve 22 for cutting off fuel supply to each fuel passage 33, 34 at main jet 21.

Next, the throttle opening Tθ is set to a high rotational return opening that can secure the amount of fuel necessary to maintain a relatively high engine rotational speed during deceleration control in the early stage of fuel recovery, and a high rotational rotation larger than the idle opening Tθ0. At the time of return, the opening degree is controlled to Tθ1, and in the fuel cut state at this throttle opening degree, the engine rotational speed NE is the rotational speed NE2 which does not require deceleration control.
For example, when the engine is put into a neutral state by the driver's driving operation or when the clutch is released, the electric control circuit 59 causes the main cut solenoid valve 22 to shut down the fuel A release signal is output, and the supply of fuel to the fuel passages 33 and 34 of the carburetor 2 is restarted (F/C: OFF).

The throttle is opened from the time when the fuel supply is restarted until the time set according to the transient characteristics of the engine, that is, the fuel passage time T1 corresponding to the time when the fuel passes through the entire fuel passages 33 and 34 after the fuel is restored. The degree Tθ is held at the degree Tθ1, and after time T1 has elapsed, the throttle opening Tθ is returned to the idle opening Tθ0 to prevent engine stalling when fuel is restored, and the throttle opening is set to an appropriate degree when fuel is restored to cause discomfort. Prevents a dangerous car shock.

That is, in step 101, the microcomputer CPU checks whether the fuel cut F/C flag is set, and if it determines that the F/C flag is not set, it moves to step 102, while checking whether the F/C flag is set. If it is determined that the person is standing, the process moves to step 108, which will be described later. Step 102
, the neutral state detection switch 51
In addition, in step 103, the idle switch 15 is ON and the drive system is in a power transmission state, and furthermore, in step 104, the engine rotation speed NE is determined by the output signal of the engine rotation speed detection sensor 48. , if it is determined that the engine rotation speed is higher than the preset predetermined engine rotation speed NE1 that requires deceleration control, in step 105,
A fuel cut signal is output from the electric control circuit 59 to the solenoid valve 22, and the fuel passage 3 of the carburetor 2 is
3 and 34 will be stopped.

In the next step 106, the actuator 7 indicated by the symbol ISC is driven to open the throttle valve 4.
The opening degree is set to a high rotation return opening degree that can secure the amount of fuel necessary to maintain a relatively high engine rotation speed during deceleration control in the early stage of fuel recovery, and is larger than the idle opening Tθ0. After setting the degree Tθ1 and setting the F/C flag at step 107, the program proceeds to the next routine.

Note that if the neutral state detection switch 51 is ON in step 102, or if the idle switch 15 is OFF in step 103, or if the engine rotation speed NE is NE1 in step 104,
If it is smaller, the engine control step is performed to the next routine since engine deceleration control is not required.

If it is determined in step 101 that the F/C flag is set, step 108 is executed. In step 108, a microcomputer for counting the set time T1
Determine whether the timer built into the CPU has started counting, and if it is determined that the timer has not yet started counting, proceed to step 109.
However, if it is determined that the timer has already started counting, follow the steps below.
Move to 116.

In step 109, the neutral state detection switch 51 is OFF, in step 110, the idle switch 15 is ON, and in step 111, it is determined that the engine rotation speed NE is higher than the set rotation speed NE2 at which the fuel cut is to be released. If it is determined that there is, step to the next routine.

Furthermore, if it is determined in step 109 that the neutral state detection switch 51 is ON, or if it is determined that the idle switch 15 is OFF in step 110,
Step 112 because deceleration control has been canceled
Then, a fuel cut release signal is output to the main cut electromagnetic valve 22, and the supply of fuel to the fuel passages 33 and 34 of the carburetor 2 is restarted, and the process moves to step 115, where the time T1 is counted. After starting the timer, step to the next routine.

In step 111, the engine speed
If it is determined that NE is below the set rotational speed NE2, step 113 is executed and a fuel cut release signal is output to the main cut solenoid valve 22 to supply fuel to the fuel passages 33 and 34 of the carburetor 2. In the next step 114, the symbol
The actuator 7 indicated by ISC is driven to set the throttle opening Tθ to a low engine speed return opening that can secure the amount of fuel necessary to maintain a relatively low engine speed without requiring deceleration control in the early stage of fuel return, and is an opening at idle. After controlling the opening degree to Tθ2 at the time of low rotation return, which is slightly larger than the opening degree Tθ0, a timer for counting the time T1 is started in step 115, and then the next routine is executed.

In the step 108, the set time T1
It is determined whether the timer that counts has started counting, and if it is determined that the timer has already started counting, step 116 is executed. If it is determined in step 116 that the timer count value has not yet reached the set time T1, the routine proceeds to the next routine, while the timer count value has already reached the set time T1.
If it is determined that the value exceeds , step 117 is executed. In step 117, the actuator 7 indicated by the symbol ISC is driven to adjust the throttle opening.
Tθ is set to the idle opening degree Tθ0, and in the next step 118, the counting of the timer is stopped and the counted value is cleared. step
At step 119, the F/
After clearing the C flag, step to the next engine control routine.

(Effects of the Invention) According to the present invention, when the throttle opening is changed to the idle opening and deceleration operation is started from an engine operating state where the engine speed is higher than a predetermined engine speed that requires preset deceleration control, the fuel passage of the carburetor is After stopping the supply of fuel, the throttle opening is set to a high engine speed return opening that can secure the amount of fuel necessary to maintain a relatively high engine speed during deceleration control in the early stage of fuel return. During the process of decelerating the engine by controlling the opening to a higher rotation than the opening, when the engine rotation speed drops to a speed that does not require deceleration control, restarts fuel supply and returns the throttle opening to fuel. For a predetermined period of time, the opening degree is a low rotation return opening degree that can secure the amount of fuel necessary to maintain a relatively low engine rotation speed that does not require deceleration control in the initial stage, and is slightly larger than the idle opening degree. That is, after the fuel passage time corresponding to the fuel passing through the entire fuel passages 33 and 34 after fuel return has elapsed, the throttle opening is controlled to return to the idle opening, while the engine rotational speed is adjusted so that the engine rotational speed does not require deceleration control. When the operating state of the engine changes to a deceleration release state before the engine speed decreases to the maximum speed, the fuel supply is restarted, and from that point on, the throttle opening is maintained at the opening at the time of high rotation return until the fuel passage time has elapsed. By controlling the throttle opening to return to the idle opening after the fuel passage time has elapsed, the fuel is cut when the engine decelerates, increasing the deceleration effect and preventing abnormal HC emissions. , and the fuel economy characteristics of the engine have been improved, and even if deceleration is released at a relatively high engine speed during deceleration control, or when the engine speed has dropped to a point where deceleration control is not required. However, it is possible to obtain smooth and stable engine deceleration characteristics without problems of engine stall and car shock.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the method of the present invention, FIG. 2 is a system diagram showing an electrical control system of an embodiment of the invention, FIG. 3 is an overall system diagram of an embodiment of the invention, and FIG. The figure is an explanatory diagram of the operation of one embodiment of the present invention, and FIG. 5 is a control flowchart of one embodiment of the present invention. S01-S10... Step, 2... Vaporizer,
3...Intake passage, 4...Throttle valve, 7...
...Actuator, 15...Idle switch,
22... Main cut solenoid valve, 24... Slow cut, 46... Throttle opening sensor, 48...
Engine speed sensor, 51...neutral state detection switch, 59...electric control circuit, CPU
...Microcomputer, ROM...memory circuit.

Claims (1)

[Claims] 1. During engine deceleration control, when the throttle lever is returned from a state where the engine speed exceeds a preset specified speed that requires deceleration control until it contacts the motor-driven throttle actuator, the fuel in the carburetor The passage is blocked and the throttle actuator operates to adjust the throttle opening to a high rotation speed larger than the idle opening that can secure the amount of fuel necessary to maintain a relatively high engine rotation during deceleration control in the early stage of fuel recovery. In addition to controlling the opening degree at the time of return, the fuel passage is opened when vehicle drive by the engine is canceled at a high rotation speed before the engine speed reaches a preset predetermined speed that does not require deceleration control. After the fuel has passed through the entire fuel passage after the return, the throttle opening is controlled to an idle opening by operating the throttle actuator, and furthermore, the engine speed is lowered to require deceleration control. A relatively low engine that does not require deceleration control at the initial stage of fuel recovery by opening the fuel passage when the rotation speed drops below a preset predetermined speed and adjusting the throttle opening degree by operating the throttle actuator. The throttle opening is controlled to a low rotation opening that is slightly larger than the idle opening that can secure the amount of fuel necessary to maintain the rotation, and the throttle is opened after the fuel passage time corresponding to the fuel passing through the entire fuel passage after the fuel is restored. A method for controlling an opening degree of a throttle valve during deceleration, characterized in that the opening degree of a throttle valve is controlled to an idle opening degree by operating the throttle actuator.