JPS6093143A - Internal combustion engine idle speed control device - Google Patents

Abstract

PURPOSE:To decrease a proportional integration constant of feedback control and promote the improvement of stability of an idle speed, by controlling the deviation, provided between a basic control value and a target speed, to be focused to zero, in the case of an idle speed control device. CONSTITUTION:An idle speed control device of an internal-combustion engine provides a basic control value setting means setting a basic control value of duty ratio of a pulse signal on the basis of cooling water temperature, feedback correction amount setting means comparing a target speed with an actual speed so as to set a feedback correction amount by proportional integration control and a study correction amount searching means stored in a random access memory (RAM) corresponding to an operating condition of the engine. Further a study correction amount correcting means adding a deviation of the feedback correction amount from a reference value to a study correction coefficient to set a new study correction amount and update equal speed data in the RAM, control value arithmetic means and a pulse signal output means outputting a pulse signal of the duty ratio to an idle control valve are provided, constituting the idle speed control device.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a learning control device for the idle speed of an internal combustion engine.

Background technology As an idle speed control device for an internal combustion engine, for example, a first
As shown in the figure, an idle control valve (ISO valve) 3 is provided in the middle of an auxiliary air passage 2 that bypasses a throttle valve 1, and the idle speed is controlled by adjusting the amount of auxiliary air by kneading. There is. Idle control valve 3
is a rotary set, and pulse signals are sent to a valve-opening coil and a valve-closing coil (not shown) in a mutually inverted state, and the degree of opening is adjusted according to the duty ratio of the pulse signals. Note that 4 is a single point injection (SPI) fuel injection valve, 5 is a hot wire air flow meter, and 6 is a blow-by gas recirculation pipe.

By the way, the Melf 46 month tute ratio to the idle control valve is determined by the control value 5Cdy, which is determined by the following equation. The control value tF is expressed in (%) and is output as the percentage of time that the valve-opening coil is at (-)N equal to 1.

l5Cdy =ISCtw+l5ce t+l'5cf
bHere, ISCtw is the cooling water temperature (hereinafter referred to as water temperature)
The dependent basic control value l5Cet is various correction amounts such as air conditioner correction and acceleration/deceleration correction, and l8Cfh is a feedback correction amount for idle rotation speed feedback control (ISC) to be described later.

Regarding feedback control of the idle speed, the target speed detected by the water temperature sensor and dependent on the free water height is compared with the actual speed detected by the crank angle sensor (hereinafter referred to as the actual speed), and the difference is determined. In this case, the control value at that time is corrected to control the target rotation speed. Therefore, the feedback correction amount l5 is
cfb has been established.

The value of the feedback correction amount l5Cfb is changed by proportional integral (PI) control to achieve stable control. That is, the target rotation speed and the actual rotation speed are compared, and if the actual rotation speed is lower (higher) than the target rotation speed, the feedback correction amount I 8 Cf l) is initially increased (lower) by P.
then raise (lower) it gradually for 1 minute at a time.

By the way, it is possible to make the rotation speed obtained by the open loop duty equivalent to the basic control value I S Ct w (or the sum of the travel and various correction amounts l5Cet) completely match the target rotation speed, and the feedback correction amount l5Cft ) becomes O, so feedback control is not necessary, but in reality the throttle chamber is clogged.
Feedback control is performed because the correlation may deviate due to variations in parts, etc.

However, if the correlation between the open torque and the target rotation speed is poor, when the actual rotation speed deviates from the target rotation speed,
It takes time until the deviation in the correlation between the open loop duty and the target rotational speed is corrected by feedback control, that is, until the rotational speed settles to the original target rotational speed. For this reason, if the PI constant of proportional-integral control is increased when setting the feedback correction amount l8Cfb, hunting, over (under) shoot, etc. will occur, resulting in unstable idle rotation and engine stall due to a drop in 5 revolutions. There is a problem.

Therefore, in Japanese Patent Application No. 58-85855, the present applicant corrected the open loop duty, that is, the basic control value through learning and correlated it with the target rotation speed.
Learning that eliminates the correlation deviation and enables quick control of the idle speed, and also improves the stability of the idle speed by making it possible to reduce the PI constant during feedback control. A control device was proposed.

That is, a map of learning correction amount l5C1e corresponding to engine operating conditions such as actual rotation speed and water temperature is provided in RAM, and ■5Cdy
The control value of the duty ratio of the pulse signal for driving the idle control valve is corrected and calculated by the learning correction amount ゛SCLt2 as shown in the following equation.

l5Cdy←ISCtw-14scet+l5cfb+
Follow the steps below to learn Isc/, e, and ■8C1e.

1) Engine operating conditions and feedback correction amount l5Cfb after a predetermined period of time has passed since feedback control was performed
and detect.

11) Search for the learned correction amount ■5C4e that has been learned and stored up to the present in accordance with the engine operating state.

111) From the feedback correction amount l8Cfb and the learning correction amount l8CLe, a new
Configure and update C4e.

However, as mentioned above, the feedback correction amount l5
In the method of setting and updating a new learning correction amount l5Ct,e by weighted average of Cfb and learning correction amount TSC1e, as the feedback correction amount l5Cfb (absolute value) decreases, the learning correction amount I S Cte (absolute value also decreases). Because of this, if learning progresses beyond a certain point, learning may no longer progress, and there is still room for improvement in terms of learning control.

<Object of the Invention> In view of the actual situation of the present invention, the idle rotation speed can be controlled by controlling the oven loop duty, that is, the deviation between the basic control value and the target rotation speed, to converge to O. In addition to making the PI constant of the feedback control smaller, it further promotes stable changes in the idle rotation speed, etc.5
The purpose is to

<Structure of the Invention> For this reason, the present invention provides basic control value setting means for setting a basic control value of the duty ratio of a pulse signal based on the cooling water temperature, as shown in FIG. @ Feedback correction amount setting means that compares the target rotation speed set based on ice water temperature and the actual rotation speed and sets the feedback correction amount by proportional-integral control, and 5. Stored in RAM in correspondence with the engine operating state. The learning correction amount search means sets a new learning correction ii1' by adding the deviation amount between the feedback correction m'' and the reference value to a predetermined proportion learning correction coefficient, and performs R.
learning correction amount correcting means for updating data of the same rotation speed in the AM; and control value calculating means for calculating a control value for the duty ratio of the pulse signal by adding the feedback correction amount and the learning correction amount to the basic control value. , and pulse signal output means for outputting a pulse signal of the tutee ratio based on the calculated control value to the idle control valve.

Example of implementation Examples will be described below.

Figure 3 shows the hardware configuration.

11 is a CPU, 12 is a P-ROM, 13 is a CMO 8-RA, M for learning control, and 14 is an address decoder. In addition, for I'tAM13, the key switch OF
In order to retain the memory contents even after F, a backup power supply circuit is used.

Analog input signals to the CPU 11 for controlling the idle control valve 3 include a water temperature signal from the water temperature sensor 15;
There are a throttle opening signal from a slot sensor 16 and a batch IJ voltage from a battery 17, which are input via an analog input interface 18 and an A/D converter 19. 20 is an A/D conversion timing controller.

Digital input signals include ON and 0FF (i) from the idle switch 21, neutral switch 22, and air conditioner switch 23, and these are input manually via the digital input interface 7ace 24.

In addition, a reference signal every 180' and a position signal every f from the crank angle sensor 25 are inputted via a one-shot multi-circuit 26, for example. Further, a vehicle speed signal from a vehicle speed sensor 27 is inputted via a waveform shaping circuit 28.

Output signals from the CPU 11 (pulse signals to the idle control valve 3) are sent to the valve opening coil 3 of the idle control valve 3 in a mutually inverted state via a phase inversion driver 29.
a and the valve closing coil 3b.

Here, the CPU 11 executes a program (stored in R, 0M12) based on the flow chart (9) shown in FIG. ), input/output operations and arithmetic processing are performed.

Next, the flowchart shown in FIG. 4 will be explained.

A basic control value I S Ct w is set from the water temperature Tw detected by the water temperature sensor 15 at Sl. This setting may be performed by storing a map of the basic control value ISCtw using the water temperature Tw as a parameter in advance in the ROM 12 and searching from the map, or by calculation.

Various correction amounts l5Cet, such as air conditioner correction and acceleration/deceleration correction, are set as necessary using Sl.

In S3, a learning correction amount ll5cte is retrieved from a map stored in the RAM 13 as will be described later from the water temperature Tw. In this case, it is desirable to use interpolation material. The map of the learning correction amount l5C4e with the rotational speed N as a parameter is stored in the rewritable RAM 13, and all l5Cte=O at the time when learning has not started (+O).

In S4, the control value l5 during open loop control is determined according to the following formula:
Calculate Cdy.

I8Cdy=ISCtw+TSCet+Tsc/, eS
In step 5, it is determined whether the ISC condition (area where ISC is performed) is met. Specifically, when the idle switch 21 that detects the fully closed position of the throttle valve is ON (throttle valve fully closed position f) and the neutral switch 22 is 0N (transmission gear position is neutral), or when the idle When the switch 21 is ON and the vehicle speed detected by the vehicle speed sensor 27 is below a predetermined value, it is assumed that the ISC condition is satisfied, and the process proceeds to the next step 86.

In S6, the target rotational speed Ns is set by searching or calculating from the water temperature Tw.

In S7, the target rotation speed Ng and the actual rotation speed N detected by the crank angle sensor 25 are compared. Then, the feedback Sodemasabyo l8Cfb is set by proportional-integral control. That is, if N s > N, the feedback compensation (11) positive amount l5Cfh is increased by a predetermined amount from the previous value based on proportional-integral control in S8.

If Ns<Nl17), reduce the feedback correction amount TSCfb by a predetermined amount from the previous value based on proportional-integral control at -89. If N5=N (insensitive, including band), the feedback correction amount TSCfb is kept at the previous value.

At 810, the control value l5 is set during feedback control.
Cdy is performed by adding the feedback correction amount l5Cfb to the value during the open loop control simulated in S4.

At 811, a pulse signal with a duty ratio corresponding to the control value 5Cdy is outputted to the opening coil 3a and closing coil 3b of the idle control valve 3 via the phase inversion driver 29. Here, during feedback control, the control value l5Cdy is a value obtained by adding the feedback correction amount l5Cfb set in 810, but when the ISC condition is not satisfied in S5, that is, when open duty control is performed, the control value l5Cdy is For 5Cdy, the value calculated in S4 is used as is.

(12) 812 to 815 are provided for updating the value of the learning correction amount ISCL e by learning.

That is, it is determined in step 812 whether or not feedback control is being performed, and if YES, it is determined in step S13 whether or not a predetermined time has elapsed since the start of feedback control, and YES.
In the case of S, the process advances to 814 to perform learning. The reason why S13 is provided is that learning will not become stable until a predetermined period of time has elapsed after entering the feedback control state, and even if learning is performed in this state, the reliability of the learning will be lacking.

In 814, based on the current feedback correction amount l8cfb and the learning correction amount TSCte retrieved from the water temperature,
Calculate according to the following formula and use the value as the new learning correction amount l
5Cte, I(, AM13 where, Δl5
Cfb is the feedback correction [18Cfb and reference value l
Deviation 1i from 5Co (△l5cfb=ISCfb-IS
Co). Moreover, M is a constant. However, the standard value l
When 5Co=0, Δl5(13) Cfb=ISCfb.

In S15, a new learning correction amount l5C4e is written into the map of the RAM 13 at the corresponding water temperature Tw.

That is, the data in R and AM 13 is updated. Note that in this case, no interpolation is required.

If the determinations at 812 and 813 are NO, the above-described learning is not performed and the routine ends.

In this way, based on the deviation amount Δl5Cfb between the feedback correction amount l5Cfb and the reference value ■SCo, the learning correction 1HIscte is updated to reduce the deviation amount Δl5Cfb and the basic control value is corrected, so that learning is sufficient. As the rotation progresses, the deviation in correlation with the target rotational speed is reduced as much as possible. As a result, it is possible to quickly control the idle speed, and it is also possible to reduce the PI constant during feedback control, which increases the stability against long-term fluctuations in the idle speed, and prevents the engine from stalling. can be effectively prevented. Additionally, since the target rotational speed can be lowered accordingly, fuel efficiency is improved.

In addition, in this embodiment, as shown at 84 in FIG. 4, the learning control amount l8CLe is added to the control value during oven loop control as shown in (14), so the control value for oven loop control is also well corrected and controlled. Characteristics improve.

Furthermore, although the learning correction amounts T and 5C1e are stored in the map corresponding to the water temperature in this embodiment, they may be stored in the map corresponding to the engine speed and the throttle valve opening.

<Effects of the Invention> As explained above, according to the present invention, the learning correction amount is newly set and updated by calculating the deviation amount between the feedback correction amount and the reference value into the predetermined proportion learning correction amount. , Basic 1 using this! Since the control value (oven loop duty) is corrected to correlate with the target rotation speed, it is possible to control the idle rotation speed as quickly as possible, and along with this, the feedback f11.
Since the PI constant during control can be made small, the stability of idling rotation can be sufficiently improved, and the risk of engine stalling etc. can be reduced. C (Naru. Furthermore, from the above (15) As a result of lowering the target rotation speed of the idle rotation speed, fuel efficiency can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a throttle chamber showing an example of an idle control valve, FIG. 2 is a block diagram showing the configuration of the present invention,
FIG. 3 is a hardware configuration diagram showing an embodiment of the present invention;
FIG. 4 is a flowchart similar to the above. 1... Throttle valve 2... Auxiliary air passage 3...
Idle control valve 11...CPU 12...P-R
OM13...CMO8-f (AM15...Water temperature sensor 25...Crank angle sensor Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Sasa &!, Fujio (1st Figure 4-269-

Claims (1)

[Claims] Basic control of the duty ratio of the pulse signal based on the cooling water temperature in an internal combustion engine equipped with an idle control valve in the auxiliary air passage that bypasses the throttle valve and whose opening degree is adjusted according to the duty ratio of the idle control valve, which is driven by a pulse signal. basic control value setting means for setting a value; feedback correction amount setting means for setting a feedback correction amount by proportional-integral control by comparing the target rotation speed and the actual rotation speed, which are set based on the cooling water temperature; A learning correction amount search means for searching a learning correction amount stored in the RAM in correspondence with the driving state of a learning correction amount correction means that sets the amount and updates the data of the same engine operating state in the RAM, and calculates the control value of the duty ratio of the pulse signal by adding the feedback correction amount and the learning correction amount to the basic control value. 1. An idle rotation speed learning control device for an internal combustion engine, comprising: a control value calculation means for calculating the calculated control value; and a pulse signal output means for outputting a pulse signal of a duty ratio based on the calculated control value to an idle control valve.