JPH0115691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine idle speed control method in which a target idle opening degree of a throttle valve is sequentially corrected by learning and memory during idle speed control after warm-up.

(Prior Art) Conventionally, as described in Japanese Patent Application Laid-Open No. 56-132430, in a system for controlling the idle speed after warming up the engine, the target idle opening degree is set in advance according to the water temperature. Each time it is detected that the idle switch changes from off to on, the actuator drives the throttle opening to the target opening and then controls the engine speed to the target speed. Even if the appropriate idle opening changes due to the influence of engine changes over time, the target idle opening remains the same as the initial setting. If the engine speed is controlled to the target idle speed while the engine speed is controlled to the idle speed, for example, the air-fuel ratio determined by the idle speed may not be appropriate, which may cause the engine to enter a rough idle state and stall. The problem was that even if the target idle opening was inappropriate due to an error in the installation of the throttle sensor, idling continued without being corrected.

(Problems to be Solved by the Invention) The present invention learns and stores the throttle opening degree during execution of idle speed control after warm-up and corrects the target idle opening degree. and to eliminate the effects of changes over time.

(Means for Solving the Problems) As shown in FIG. 1, the present invention controls the opening position of the slot valve by driving an actuator based on signals from various sensors corresponding to the engine operating state. When controlling the engine speed to the target idle speed, it is determined in step SO1 whether or not idle speed control is being executed in a state where a specific learning condition is satisfied, and when idle speed control is being executed, the idle speed of the engine is determined in step SO2. is within the dead band of the target idle speed, and if it is within the dead band, the difference between the target idle opening of the throttle valve determined by the target idle speed and the actual throttle opening is determined in step SO3. At step SO4, it is determined whether the throttle opening difference is greater than or equal to a predetermined opening.
The engine idle speed control method sequentially corrects and stores the target idle opening so that the throttle opening difference becomes equal to or less than the predetermined opening at SO5.

(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). The closed position of the valve 4 is controlled by an actuator (ISC) 7, in which the operation lever 6 fixed to the shaft 5 of the throttle valve 4 is capable of reversible operation.
The touch head 12 at the tip of the actuator 7 rotates the threaded rod 10 in forward and backward directions via the DC motor 8 and gear train 9 to move the output shaft 11, which is screwed together with the threaded rod 10 whose movement in the circumferential direction is restricted, back and forth. The contact of the operating lever 6 with the touch head 12 is determined by the contact of the operating lever 6 with the touch head 12, which causes the final gear 14 to move slightly backward together with the output shaft 11 against the biasing force of the spring 13, thereby causing the idle switch 15 to be activated. The stroke end of the output shaft 11 is detected when the output shaft 11 is turned on.
This is detected when the upper dog 16 comes into contact with the lever 18 of the limit switch 17.

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 O2 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 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 throttle valve opening from the throttle opening sensor 46, and an O2 sensor Each of the analog signals corresponding to the oxygen concentration from 50 to A/
is inputted via the input port 62 after being converted into a digital signal via the D converter 61, and
On/off signals from the idle switch 15, clutch/neutral detection switch 51, air conditioner switch 54, pulse output vehicle speed sensor 49, ignition key switch 56, starter switch 55, side lamp switch 52 are input ports. 63, and to the output port 64 of the microcomputer CPU,
Actuator 7 via each drive circuit 65 to 69
The DC motor 8, 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 57 are connected, as well as the output port 70.
A stepper motor 26 of the air bleed control valve 25 is connected to the air bleed control valve 25 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 and a target idle rotation speed that change according to the engine cooling water temperature, and during idling after warm-up, the engine adjusts the throttle valve 4 to the target idle opening. In the set state, the idle speed is controlled to reach the target idle speed, and during the idle control, the target idle opening degree is controlled by learning according to the flowchart shown in FIG.

That is, in step 101, the learning conditions, in this case,
For example, it is determined whether or not a learning condition in which a stable idle opening degree can be obtained with the electric load such as the side lamp switch 52 off is established. If the learning condition is established, the target rotation speed in the idle rotation speed control is set to warm up in step 102. It is determined whether the target idle speed after warming up is, for example, 650 rpm, and if it is the target idle speed after warming up, the idle speed control is started in step 103, and then the target is maintained for a predetermined period of time, for example, 5 seconds or more. It is determined whether or not the idle speed is within the dead band, and in a stable idle operation state within the dead band, the target idle opening initially set in step 104, for example, corresponding to the target idle speed of 650 rpm after warming up, is determined. When the set idle opening is 1 degree, as shown in Fig. 4, this target idle opening Λ and the actual throttle opening Ψ at the target idle rotation speed of 650 rpm after warming up
The difference Δ is calculated, and in step 105 this difference Δ
It is determined whether or not the opening is at least a predetermined opening with virtually no difference, and if the opening is at least the predetermined opening, the target idle opening Λ has not reached an appropriate value, and step 10
6, it is determined whether this difference Δ is + or -, and step 1
At 07 and 108, a constant ω is added or subtracted corresponding to this ± direction, and the target idle opening is, for example, the 5th
As shown in the figure, ε is updated by a certain amount and learned and stored, and when this difference Δ becomes less than a predetermined opening with virtually no difference, this learning and storage is not performed and the updated optimal target idle opening is The degree Λ is stored in the RAM with backed up power, and the target idle opening according to the water temperature is appropriately set as this target idle opening Λ + α (α is a constant), and this target idle opening Λ + β (β is a constant) In addition to appropriately setting the target idle opening according to the DP opening, it is also possible to reliably prevent the effects of installation errors of the throttle sensor 4 and changes in idle over time, such as rough idling and engine stalling.

(Effects of the Invention) The present invention learns and stores the throttle opening degree during execution of idle rotation speed control after warm-up and updates the target idle opening degree to an appropriate opening degree. Also, there is an effect that the idle operating characteristics of the engine can always be maintained at the optimum characteristics by eliminating the influence of changes over time.

[Brief explanation of drawings]

FIG. 1 is a flowchart clearly showing the method of the present invention, FIG. 2 is an explanatory diagram of an embodiment of the present invention, and FIG.
FIG. 4 is its electrical circuit diagram, FIG. 4 is its flowchart, and FIG. 5 is its operating characteristic diagram. SO1~SO5...step.

Claims (1)

[Claims] 1. When controlling the engine idle speed to the target idle speed by controlling the throttle valve opening position by driving the actuator based on signals from various sensors corresponding to the engine operating state, a specific learning condition is satisfied. When the idle speed of the engine is within the dead band of the target idle speed, the difference between the target idle opening of the throttle valve determined by the target idle speed and the actual throttle opening is detected, and the throttle opening is determined. Engine idle speed control characterized in that the target idle opening degree is sequentially corrected and stored so that the throttle opening difference becomes equal to or less than the predetermined opening degree when the difference is greater than or equal to a preset predetermined opening degree. Method.