JPH0359257B2 - - 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 Throttle position method throttle valve opening control during deceleration is used, 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 deceleration rate set in advance in accordance with the engine characteristics. This effectively prevents abnormal HC emissions by controlling the idle opening to stabilize the deceleration characteristics of the engine. However, in this case, since fuel is not cut during deceleration, the fuel efficiency characteristics of the engine deteriorate. 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 or restricting fuel during deceleration.In this case, fuel cut 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 if you control the throttle opening during deceleration to the extent that the engine does not stall, An unpleasant car shock is likely to occur when the fuel is restored while the gear is still connected.
In addition, if the deceleration time is short, the fuel that had accumulated in the fuel passage of the carburetor will be supplied to the intake passage at once when the deceleration control is canceled and the engine is in neutral, causing the engine speed to decrease. There were drawbacks such as the temporary rise in height, causing an uncomfortable car shock.

(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. To obtain smooth and stable engine deceleration characteristics without causing car shock problems.

(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. The idle opening Tθ0 is maintained during a certain residual fuel consumption time T1 corresponding to the consumption of the residual fuel in the fuel passage due to the operation of the yuator.
At the same time, in step S05, it is determined whether or not T1 of the residual fuel consumption time has elapsed, and after T1 has elapsed, in step S06, the throttle opening is controlled to a slightly larger opening Tθ1 during deceleration. By operating the engine, the opening degree at the time of return is controlled to Tθ2 that can secure the amount of fuel necessary to maintain the engine rotation at the initial stage of fuel recovery, and furthermore, in step S07, the engine rotation speed is controlled to a preset predetermined rotation that does not require deceleration control. It is determined whether or not the number of NE2 has become less than NE2, and when it becomes less than NE2, the fuel passage is opened in step S08, and the fuel passage time corresponding to the time when the fuel passes through the entire fuel passage after recovery in step S09 is determined. Determine whether T2 has elapsed or not, and after T2 elapse, step S10
The present invention provides a method for controlling the opening degree of a throttle valve during deceleration, in which the throttle opening degree is controlled to an idle opening degree Tθ0 by operating the throttle actuator.

(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 through the air passages 31 and 32 to the main system and slow system fuel passages 33 and 34 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 and acceleration, 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 an output, a water temperature sensor 47 attached to the water jacket of the engine, and an engine rotation speed sensor 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 switch circuit 57 each have their power supply from the battery 58 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 engine rotation from the engine rotation speed sensor 48 via a waveform shaper 60. In addition to inputting a pulse signal with a frequency corresponding to the number, an analog signal corresponding to the engine cooling water temperature from the water temperature sensor 47, an analog signal corresponding to the opening of the throttle valve 4 from the throttle opening sensor 46, and an analog signal corresponding to the opening of the throttle valve 4 from the throttle opening sensor 46 are input. ₂ analog signals corresponding to the oxygen concentration from the sensor 50 are inputted via the input port 62 after being converted to digital signals via the A/D converter 61, and are also input to the idle switch 15 and the clutch. On/off signals from each of the neutral detection switch 51, air conditioner switch 54, pulse output vehicle speed sensor 49, ignition key switch 56, starter switch 55, and side lamp switch 52 are inputted via the input port 63. or,
The output port 64 of the microcomputer CPU is connected to the DC motor 8 of the actuator 7, the solenoid coil 36 of the auxiliary fuel pump 35, the main cut solenoid valve 22, the slow cut solenoid valve 24, and the alternator control circuit 5 via each drive circuit 65 to 69.
In addition, the stepper motor 26 of the air bleed control valve 25 is connected to the output port 70 via a drive circuit 71.

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 NEO, 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 the idle opening set according to the consumption of residual fuel in the fuel passages 33 and 34 at the time of fuel cut.
An opening degree during deceleration Tθ1 that is slightly larger than Tθ0, an opening degree during return Tθ2 that is larger than the opening degree during deceleration Tθ1 that can secure the amount of fuel necessary to maintain the engine rotation at the initial stage of fuel recovery, and fuel remaining in the fuel passages 33 and 34. Constant residual fuel consumption time T corresponding to fuel consumption
1 and a fuel passage time T2 corresponding to the time when fuel passes through the entire fuel passages 33 and 34 after the fuel is restored, and during deceleration in this hypothetical state, the engine operates according to the flowchart in FIG. First, the operation diagram shown in FIG. 4 will be explained.

Currently, the engine operating state is neither idle (idle switch 15 OFF) nor neutral (neutral switch 51 OFF).
When the vehicle is being driven by the engine, and the engine rotational speed NE is equal to or higher than a relatively high predetermined engine rotational speed NE1, which is set in advance to execute throttle opening control during engine deceleration,
When the idle switch 15 is turned on, the engine enters deceleration operation in this state, and the throttle opening changes.
Tθ is closed to the idle opening degree Tθ0, and the electric control circuit 59 is connected to each fuel passage 33, 3.
The main cut solenoid valve 22 for cutting off the fuel supply to the main jet 21 at the main jet 21 position is activated.

Next, the throttle opening Tθ is a deceleration opening set corresponding to the consumption of residual fuel in the fuel passages 33 and 34 at the time of fuel cut, and is the idle opening.
The deceleration opening Tθ1 is controlled to be slightly larger than Tθ0, for example by about 3° to 6°, and this deceleration opening Tθ1
Compare the residual fuel in a state in which abnormal HC discharge is effectively prevented by maintaining the state for T1 time, which is set to a time slightly shorter than the time for which the fuel remaining in the fuel passages 33 and 34 of the carburetor 2 becomes empty. After the throttle opening Tθ1 is consumed in a relatively short period of time and the throttle opening Tθ1 is continued for T1 hours, the throttle opening Tθ is set at a return speed that can secure the amount of fuel necessary to maintain the engine rotation at the initial stage of fuel return; Opening degree Tθ
The opening degree Tθ2 at the time of return is controlled to be greater than 1 by Δθ.

With the throttle opening degree Tθ controlled to Tθ2, the engine deceleration further progresses and the engine rotational speed NE
However, when the rotation speed drops to NE2 which does not require deceleration control and which should release the fuel cut, the solenoid valve 22 is activated.
Turn off and restart fuel supply.

From the time when the fuel supply is restarted to the time T2 set corresponding to the transient characteristics of the engine, that is, the fuel passage time T2 corresponding to the time when the fuel passes through the entire fuel passages 33 and 34 after the fuel is restored. The throttle opening Tθ is held at the return opening Tθ2 to stabilize the engine speed even if the gear becomes neutral at this point, and after the set time T2 has elapsed, the throttle opening Tθ is returned to the idle opening Tθ0 and the normal idle is resumed. control.

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 robot is standing, the process moves to step 109, which will be described later.
In step 102, it is determined that the neutral state detection switch 51 is OFF and the drive system is in a power transmission state.In step 103, it is determined that the idle switch 15 is ON and the deceleration state is in progress.Furthermore, in step 104, the engine rotational speed is
If it is determined that NE is greater than a preset engine speed NE1 that requires deceleration control, in step 105, a fuel cut signal from the electric control circuit 59 causes the electromagnetic valve 22 to
to operate the fuel passages 33 and 34 from the carburetor 2.
Stop fuel supply to.

In the next step 106, the actuator 7 indicated by the symbol ISC is driven to set the opening degree of the throttle valve 4 to the opening degree Tθ1 during deceleration, and
In step 107, the residual fuel consumption T1
The timer 1 that counts time is started, and in step 108, the F/C flag is set to proceed to the next engine control routine, and if the neutral state detection switch 51 is ON in step 102, Alternatively, if the idle switch 15 is OFF in step 103, or if the engine speed NE is smaller than NE1 in step 104, engine deceleration control is not required and the next engine control is performed. Step through the routine.

Next, in step 101, if it is determined that the F/C flag is set, step 1
09, and the neutral state detection switch 5
1 is ON or OFF, and if it is determined that it is OFF, in the next step 110, it is checked whether the idle switch 15 is ON or OFF. At step 110, idle switch 1
If it is determined that 5 is ON, the engine is in a state that requires deceleration control, and the next step 1 is
In step 11, it is checked whether the engine rotation speed NE is greater than the engine rotation speed NE2, which does not require deceleration control to release the fuel cut, and if NE>NE2 is satisfied, in the next step 112, the residual fuel consumption is reduced. It is determined whether the count number of timer 1 that counts time T1 is greater than set time T1. If it is determined in step 112 that the count number of timer 1 is greater than the set time T1, in step 113, the actuator 7 is driven, the throttle opening is set to the return opening Tθ2, and the next step is started. At step 114, the count of timer 1 is cleared and the next engine control routine is executed.

On the other hand, 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,
Alternatively, if it is determined in step 111 that the engine speed NE is smaller than NE2, the engine deceleration control is not necessary, so the process moves to step 115, where the fuel cut is canceled, and in the next step 116, the fuel cut is canceled. If the count of the timer 2 which counts the fuel passage time T2 has not yet counted up to the set time T2, in step 117, it is determined whether or not the counting of the timer 2 has started. If it is determined that the counting of the set time T2 has not started, then in step 118, timer 2 is started and the next engine control routine is executed.

Further, in step 116, if the timer 2 has completed counting up to the set time T2, the process proceeds to step 119. In step 119, the actuator 7
and sets the throttle opening to the idle opening Tθ0 of normal idle control. In the next step 120, the count of timer 2 is stopped and the count of timer 2 is cleared, and in step 121, the F/C plug is cleared and the next routine of engine control is executed.

(Effects of the Invention) The present invention allows the throttle opening to be changed from the idle opening Tθ0 to the carburetor opening when the engine enters deceleration operation from a predetermined engine speed NE1 or higher operating state that requires preset deceleration control. After stopping the supply of fuel to the fuel passage, the throttle opening is adjusted according to the consumption characteristics of the fuel remaining in the fuel passage of the carburetor, and the opening during deceleration corresponds to the residual fuel consumption.
After controlling the throttle opening to Tθ1 to consume the residual fuel in a relatively short period of time, the throttle opening is further controlled to Tθ2 at the time of return, which can secure the amount of fuel necessary to maintain the engine rotation at the initial stage of fuel recovery. When the engine speed decreases to the preset engine speed NE2 that does not require deceleration control to release the fuel cut, the fuel supply from the carburetor is restarted, and the transient state of the engine at the time of residual fuel consumption is restarted. The holding time T1 of the throttle opening Tθ1 set corresponding to the characteristics is set according to the residual fuel consumption time,
The holding time T2 of the throttle opening Tθ2 at the time of restarting the fuel supply is set according to the time for the fuel to pass through the entire fuel passage after the fuel is restored, and the fuel passage time T
By returning the throttle opening to the idle opening after 2 elapses, fuel is cut when the engine decelerates, increasing the deceleration effect, preventing abnormal HC emissions, and improving the fuel ratio characteristics of the engine. , 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...carburizer, 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
…Electrical 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 shut off and the throttle actuator is operated to adjust the throttle opening to a deceleration opening slightly larger than the idle opening for a certain residual fuel consumption time corresponding to the consumption of the residual fuel in the fuel passage. At the same time, after the residual fuel consumption time has elapsed, the throttle opening degree is controlled by the operation of the throttle actuator to a return opening degree that can secure the amount of fuel necessary to maintain the engine rotation at the initial stage of fuel recovery. Further, the fuel passage is opened when the engine rotational speed falls below a preset rotational speed that does not require deceleration control, and after the fuel passage time corresponding to the fuel passing through the entire fuel passage after restoration has elapsed. 1. A method for controlling an opening degree of a throttle valve during deceleration, characterized in that the throttle opening degree is controlled to an idle opening degree by operating the throttle actuator.