JPS58174144A - Idle speed controller - Google Patents

Abstract

PURPOSE:To control an engine speed to a stable state, by gradually decreasing the opening of an idle speed control valve from full opening to an opening value, in which a study value and corrective value with cooling water temperature as the parameter are added, at idle time immediately after starting. CONSTITUTION:An idle speed control valve (ISC valve) 13 concurrently providing a cold idle control function is provided to a bypass passage 12 of an intake pipe. On the basis of a study value by signals from a throttle position sensor 10 and rotary angle sensor 18 as an idle detecting means and from a start detecting means 21 of an internal-combustion engine and by an opening of the ISC valve under feedback control in the preceding time, the ISC valve is controlled, at idle operation immediately after starting, the valve opening is gradually decreased from full opening to an opening value, in wich the study value and a corrective value with cooling water temperature as the parameter are adeed, and the ISC valve at full opening gradually decreases its opening.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an idle speed control device-1, particularly a device that controls the idle speed by controlling the opening degree of an idle speed control valve having a cold idle control function at engine startup. 1- This is related to.

In recent years, with the deterioration of the energy situation, the demand for lower fuel consumption of automobiles has increased, and in conjunction with the tightening of exhaust gas regulations, various methods have been proposed. One such method is to precisely control the idle speed according to various conditions under which the engine is placed, such as intake air flow and engine cooling water temperature.

This method is usually called an idle speed control system (hereinafter referred to as ISO) and attempts to control the idle speed to a desired value, that is, the target speed by adjusting the amount of air flowing into the bypass path of the throttle valve during idle. It is.

Similarly, by using ISO, which also has a cold idle control function, at the time of starting, in order to enable internal combustion *ni to start, the ISO valve is fully opened, and then after starting, the ISO
A method of reducing the opening degree of the valve to the target opening degree has been considered.

However, with this method, the ISC knob immediately closed from fully open at startup to the target opening, resulting in unstable engine rotation and, in some cases, an engine stall. As a result, the valve opening had to be kept wide and the engine speed had to be increased, resulting in poor fuel efficiency.

The present invention aims to prevent the above-mentioned phenomenon and improve fuel efficiency, and solves the problem by gradually reducing the opening degree of the ISO valve.

That is, the gist of the present invention is to provide an idle speed control means having a cold idle control function, an internal combustion slight start detecting means, an internal combustion engine idle state detecting means, and an idle speed control means having a cold idle control function. control means for controlling the idle speed control valve based on a learned value based on the opening degree of the idle speed control valve when the engine is started; A correction value using the partial water temperature as a parameter was added:.

An idle rotation speed control device is characterized in that the opening degree is gradually decreased to an opening value. 1 The present invention will be described below with reference to an embodiment and the accompanying drawings.

1 is the engine body, 2 is the piston, 3 is the spark plug, 4
is an exhaust manifold; 5 is an oxygen sensor provided in the exhaust manifold 4 and detects the residual oxygen concentration in the exhaust gas; 6;
1 is a fuel injection valve that injects fuel into the intake air of the engine body 1, 7 is an intake manifold, and 8 is an intake manifold 7
9 is a water temperature sensor that detects the temperature of engine cooling water, 10 is a throttle valve, and 11 is interlocked with the throttle valve 10; 10
12 is a bypass passage which is an air passage that bypasses the throttle valve 10; 13 is an idle speed sensor which controls the opening area of the bypass passage 12 and also has a cold idle control function. A control valve (hereinafter simply referred to as an ISC valve), 14 an air meter for measuring the amount of intake air, and 15 an air cleaner for purifying the intake air. Of these, the bypass passage 12 and the ISC valve 13 correspond to idle speed control means, and the throttle position sensor 10 and rotation angle sensor 18 correspond to internal combustion engine idle state detection means. The maximum opening degree of the ISO valve here is approximately 30 r in terms of air flow rate.
rr/h is common.

Further, 16 is an igniter that outputs the high voltage necessary for ignition;
7 is a distributor that is linked to a crankshaft (not shown) and distributes the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder; 18 is installed inside the distributor 17, and is connected to the crankshaft for one revolution of the distributor 17, that is, the crankshaft; A rotation angle sensor that outputs a pulse signal 24 times per 2 rotations, 19 is 1 of the distributor 17
Cylinder discrimination sensor that outputs a pulse signal once per rotation, 2
0 represents an electronic control circuit, 21 represents a key switch, and 22 represents a starter motor. Of these -5-, the key switch 21 corresponds to internal combustion slight start detecting means.

Next, FIG. 2 shows a block diagram of the electronic control circuit 20. As shown in FIG.

30 is a central processing unit (hereinafter simply referred to as CPLJ) that inputs and calculates the data output from each sensor according to a control program, and performs processing for controlling the operation of various devices such as the SC valve 13;
31 is a read-only memory (hereinafter simply referred to as ROM) in which the control program and initial data are stored, and 32 is a random access memory (hereinafter simply referred to as ROM) in which data input to the electronic control circuit 20 and data necessary for performance control are read and written. 33 is designed to retain data necessary for engine operation even when the key switch 21 is turned off.
A backup random access memory (hereinafter simply referred to as backup RAM) backed up by a battery, an input port 34 (not shown), a waveform shaping circuit provided as necessary, and a CPU that outputs the output signals of each sensor.
-6- 30, an input section is provided with a multiplexer for selectively outputting the signal, an A/DI converter for converting an analog signal into a digital signal, and the like. In addition to input ports (not shown), 35 is an input/output section provided with an output port and other drive circuits for driving the ISG valve 13 and the like according to control signals from the CPU 30 as required; 36 is a C
The path lines connecting each element such as the PU 30 and ROM 31, the input section 34 and the output section 35 and through which each data is sent are shown.

Next, FIG. 3 shows a flowchart of the processing of the apparatus of the present invention.

Reference numeral 51 represents an ISO start-up processing section.

Here, step 52 represents a determination as to whether or not it is time to start,
The determination is made based on the signal from the key switch 21, which is a detection means at the time of starting the internal combustion engine.

If it is the time of starting, the process moves to step 53; otherwise, the process moves to step 55.

Step 53 represents the process of opening the ISO valve to 100%, that is, fully opening.

-7- Step 54 represents the process of setting a decrease flag.

Step 55 represents a process for determining a correction value α of the ISG valve opening for warming up.

The plane has engine cooling water 1 as α-f (THW).
! It is expressed as a function with T'HW as a parameter, and the relationship is such that the larger the value of THW, the smaller α becomes. In this case, it is preferable that the relationship be such that a convex locus is drawn downward as shown in FIG. However, α≧O.

In addition to processing the relationship α-f (THW>) using a calculation formula, the value of α may be determined based on a map set in the ROM and by constantly referring to the value.

Step 56 represents a determination as to whether or not a decrease flag is set. If the flag is set, the process moves to step 57; otherwise, the process moves to step 64.

Step 57 represents the process of calculating the product of α calculated in step 55 and a constant. K is a value exceeding 1 by -8-, and therefore Kα is a value exceeding α.

However, when α−〇, it becomes equal to α−〇.

Step 58 represents a determination as to whether or not a predetermined period of time has elapsed since the ISO valve opening 11 [D reduction process was performed last time. The determination may be made based on whether or not the engine has rotated for a predetermined time instead of the predetermined time.

If a predetermined period of time has elapsed or if the engine has rotated a predetermined number of revolutions, the process proceeds to step 59; otherwise, the process exits from this process 51 and proceeds to ISO feedback process 71.

Step 59 represents a determination as to whether or not the current opening of the ISO valve exceeds the sum of the opening learning value DG and α. If it does, the process proceeds to step 60; otherwise, the process proceeds to step 61. Processing moves on.

Step 60 represents a process of decreasing the open tID by a predetermined value a.

Step 61 represents a determination as to whether or not D exceeds the sum of DG and α. If it does, the process proceeds to step 62; otherwise, the process proceeds to step 63.

Step 62 represents the process of decreasing D by a predetermined amount of 1b. Here, since b is a value less than 8 as described above, the speed at which D is reduced by the reduction process in step 62 is slower than that in step 60.

Step 63 represents the process of defeating the decrease flag.

Next, 71 represents an ISO feedback processing section.

Here, it is determined whether the feedback condition has been met,
If the condition is satisfied, the ISG valve feedback process is executed, and then the flow is moved to other processes.

Next, based on actual processing, we will follow the processing performed by the apparatus of the present invention while also referring to FIG. 4, which shows the change in ISO valve opening degree over time.

First, the engine is started by turning on the key switch 21. At the time of starting, rYEsJ is determined in step 52, and the process moves to the stay 10-tub 53.

In step 53, the ISO valve 13 is fully opened (D=100%) to start the engine.

Then, in step 54, a decrease flag is set.

Next, the process moves to the ISO feedback process, but since the opening degree of the ISC valve 13 has just become fully open, the feedback process is not performed and the process of this flow ends.

The above process continues until the engine starts, and the ISO
The valve remains fully open. 1SC valve opening degree is 4th
The figure shows a flat state before time t1.

Next, when the engine starts running, in step 52,
The determination is "NO" and the process moves to step 55. Fourth
In the figure, this corresponds to time t,,1.

Then, in step 55, the value of α is determined, where α is R
Stored during AM.

In the determination at step 56, since the decrease flag has already been set at step 54, the result is "YES" at -11-, and the process moves to step 57.

In step 57, the product of α obtained in step 55 and a constant is obtained. Kα is also stored in the RAM like α.

Then, in step 58, the time interval for the opening reduction is adjusted. Here, rYEsJ is determined for a certain period of time or every certain rotation of the engine, and the process proceeds to step 59.
Move to.

Next, in step 59, the magnitude of the opening degree is determined based on the value obtained by adding α to the learned opening value DG of the ISC valve 13.

Here, the values of α and K in step 55 and step 57 are determined so that α<100% for DG+.

Since the valve is fully open in the process of step 53, the determination in step 59 is rYESJ,
Processing then moves to step 60.

In step 60, the opening degree is reduced by a constant value a, and thereafter the state of α continues as D>DG+ (as long as the opening degree -12- decreases by a every certain time (constant engine rotation)). becomes.

This decreasing state is shown in FIG. 4 from time t1 to time t2.
This corresponds to the steep slope between.

Next, when D decreases and becomes a state of α such that D≦DG+, it is determined that “l” is NOJ in step 59, and the process proceeds to step 6.
Move to 1.

In step 61, the degree of opening is determined based on the value obtained by adding α to DG.

Assuming that α≠O, since Kα〉α, DG+
Since α>DG+α, the process at the first step 61 is determined to be rYEsJ, and then the process moves to step 62.

In step 62, processing is performed to reduce the opening degree by a certain value, and thereafter, as long as the state of D>DG+α continues, the opening degree will decrease by b every certain time (constant engine rotation).

This decreasing state is shown in FIG. 4 from time t2 to time t3.
This corresponds to the relatively gentle slope between In order for the slope to become gentle in this way, it is necessary that a>b.

-13- Next, when D continues to decrease and reaches the state of D=DG+α, the determination in step 61 is "NO", and the process proceeds to step 6.
Move on to 3. In FIG. 4, this corresponds to time t3.

In step 63, processing is performed to set down the decrease flag.

Thereafter, this opening state continues until the cooling water temperature rises and reaches α-〇. The opening degree is at time ts in Figure 4.
After that, it is in a flat state.

Although not shown in FIG. 4, if the cooling water temperature rises to α-0, from that point on, the ISO pulp opening degree will be feedback-controlled by the ISO feedback process.

Although the above reduction in the ISO valve opening was performed in two stages, it may be reduced in multiple stages of two or more stages. In this case, the steps must be arranged so that the slope is always gentle. Conversely, as shown in FIG. 5, from the engine starting time t11, the opening degree D=DG+α is reached at the time t1.
It may be decreased at a constant rate of decrease up to 2. Alternatively, it may be changed smoothly so as to draw a downwardly convex curve like -14-.

However, since high-speed rotation is only required at the very beginning,
From the viewpoint of improving fuel efficiency, it is preferable to divide the change into multiple steps as described above rather than changing in one step as shown in FIG.

In addition, the time from engine start until the opening decreases and the reduction flag is knocked down, and the ■SC valve is controlled by ISO feedback processing is usually 20 to 30 seconds or 400 to 500 engine revolutions. It is.

As described above, the device of the present invention has an idle speed control means having a function of cold idle control a, an internal combustion engine start detection means, an internal combustion engine idle state detection means, and a signal from each detection means and a time during previous feedback. and a control means for controlling the idle speed control valve based on a learned value based on the opening degree of the idle speed control valve, and when idling immediately after starting the internal combustion engine, the valve opening degree is changed from fully open to the learned value and the cooling water temperature -15.
- By gradually decreasing the opening of the SC valve, which is fully open at startup, by adding a correction value using the parameter as a parameter, the SC valve gradually decreases, and the value changes suddenly.
This prevents unstable engine rotation or engine stall, allows for smooth changes in engine rotation, and prevents deterioration of fuel efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram showing an idle speed control device and its surroundings according to an embodiment of the present invention, FIG. 2 is a block diagram showing its electronic control part, and FIG. 3 is a flowchart showing the flow of its processing. Figures 4 and 5 are 1. A graph showing the change in SC valve opening over time, Figure 6 is for ISG valve N.
It is a graph which shows the relationship between correction value (alpha) of li and cooling water temperature Tl-1'W. 10...Throttle valve 11...Throttle position sensor 13...NS
C valve 18... Rotation angle sensor 20... Electronic - IvA port - 16 - 21... Key switch - 17 - Fig. 4 Fig. 5 267 - Fig. 6 Sulfur

Claims (1)

[Claims] 1 Idle speed control means with cold idle control function, internal combustion*a start detection means, internal combustion engine idle state detection means, signals from each detection means and the opening degree of the idle speed control valve when it was being fed back last time and a control means for controlling the idle speed control valve based on the learned value. Idle speed III 11111 characterized by gradually decreasing the valve 1ll11 degrees from fully open to an opening value obtained by adding a learning value and a correction value using the cooling water product as a parameter during idling immediately after startup.
@place.