JPS59185843A - Idle revolution speed controller - Google Patents

Abstract

PURPOSE:To control the idle revolution speed in warming correctly to an optimum value by installing a cooling-water temp. sensor, memory means for cooling-water temp., temp. difference correction amount determining means for cooling-water temp., and an intake flow-rate adjusting means, onto the idle revolution speed controller for an internal-combustion engine. CONSTITUTION:A throttle valve 12 is installed in the intake passage 10 of an engine, and a control valve 6 is installed in a bypass intake passage 14. The opening and closing operation of said control valve 16 is controlled by a valve controlling motor 18. Said motor 18 is excited by the electric current supplied by a driving circuit 20. Into the driving circuit 20, a driving signal is supplied from a control circuit 24. A cooling-water temp. sensor 26 is installed onto the cylinder block of the engine, and the cooling-water temp. detected is supplied into the control circuit 24. A crank-angle sensor 30 generates a crank angle signal each time when a crank angle turns by a prescribed angle, e.g. 30 deg., and said angular signal is supplied into the control circuit 24, and the revolution speed of the engine can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the idle rotation speed of an internal combustion engine, particularly the idle rotation speed during warm-up.

Idle rotational speed is generally controlled by adjusting the amount of air flowing into the engine at idle. During warm-up, the intake air flow rate is adjusted in an open loop to a value that corresponds to the cooling water temperature.

However, even if the cooling water temperature is the same, the friction of the engine during warm-up may differ from each other.

Even if the idle rotation speed is simply oven-loop controlled according to the cooling water temperature, the actual rotation speed may not reach the desired value. For example, even if the cooling water temperature is 50"C, if the engine is started from 125"C or 40"C (
The friction of the engine differs significantly between the two (at restart).

This is a difference that occurs because the lubricating oil temperature of the engine is different, and the above problem can be solved by detecting the lubricating oil temperature using an oil temperature sensor and controlling the idle rotation speed according to the detected value. This is undesirable because it increases the complexity and cost of the oil temperature sensor itself and its peripheral circuits.

The present invention therefore aims to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide an idle rotation speed control device that can correctly control the idle rotation speed to the optimum value during warm-up, and does not require the addition of a special mechanism for this purpose.

To explain the interception of the present invention with reference to FIG. 1, there is a means for detecting the cooling water temperature of one engine a, a means C for storing the cooling water temperature detected immediately before the engine a stops operating, and a means C for storing the cooling water temperature detected immediately before engine a stops. Means d for obtaining a °C correction value according to the difference between the coolant temperature detected during operation and the coolant temperature stored in the storage means C, and adjusting the intake air flow rate of the engine A during idling according to the correction amount. The device of the present invention includes means e to do this.

The present invention will be explained in detail below with reference to Examples.

FIG. 2 shows a schematic configuration of an embodiment of the present invention.
In the figure, reference numeral 10 indicates an intake passage of the engine, and reference numeral 12 indicates a throttle valve provided in the intake passage 10. The bypass intake passage 14, which connects the upstream intake passage and the downstream intake passage of the throttle valve 12 by bypassing the throttle valve 12, has a control valve 16 that controls the cross-sectional area of the passage.
is provided. This control valve 16 is operated by a valve control motor 18 consisting of a step motor or a DC servo motor.
The opening/closing valve operation is controlled by. The motor 18 is energized by a current fed through the wire 22 from the drive circuit 20 . A drive signal is sent to the drive circuit 20 from the control circuit 24 .

A cooling water temperature sensor 26 is attached to the cylinder block of the engine (not shown), and the detected cooling water temperature T
A voltage signal representing HW is sent to the control circuit 24 via a line 28.The crank angle sensor 30 generates a crank angle signal every time the crankshaft rotates by a predetermined angle, for example, 30 degrees. The angle signal is sent to the °C control circuit 24 via line 32.
sent to.

As is well known, when the intake air flow rate 1r is adjusted by the throttle valve 12 or the control valve 16, an amount of fuel corresponding to this intake air flow rate is supplied, and therefore the rotational speed of the engine is controlled by the throttle valve 12 or the control valve 16. It lies in being done.

FIG. 3 is a block diagram mainly showing the control circuit 24 of FIG. 2 in detail. The control circuit 24 is mainly composed of a stored program type digital computer. A digital computer has a central processing unit (CPU) 40 that performs various arithmetic processing, a random access memory (RAM) 41 that can write and read data, and can retain its memory contents even after the ignition switch is turned off. Backup RAM that can be read
44. It is equipped with a read-only memory (ROM) 46 - a human power interface 48 and an output interface 50 in which control programs, various tables used in calculations, etc. are stored in advance, and these are connected to the bus 5.
2 are connected to each other through 几℃.

The input interface 48 is fully equipped with an A/D converter, and the voltage signal sent from the cooling water temperature sensor 26) is converted into an A/D conversion instruction signal sent from the CPU 40 at regular intervals by this A/D converter. Accordingly, the ``c binary signal'' is converted.

The crank angle signal from the crank angle sensor 30 is input into the °C digital computer via the input interface 48, and the rotational speed NE' is determined by a known software method.
A binary signal representing c- is repeatedly formed. This binary signal is then stored and updated in the RAM 42.

The output interface 50 includes a drive circuit 2 for the valve control motor 18, which in the example of FIG. 3 is represented as a step motor.
0 is connected. The drive circuit 20 outputs an excitation current for the step motor 18 in response to a 4-bit drive signal sent from the CPU 40 via the bus 52.

Next, the operation of this embodiment will be explained according to the flow chart shown in FIGS. 4 to 7.

FIG. 4 shows a process that is provided in the middle of the main process routine, and steps 62 and 63 are executed only once immediately after engine start IJ71. First, in step 60, it is determined whether the rotational speed NE stored in the RAM 42 is 500 rpm or more. N
If E<500 rpm, it is assumed that the engine has not started yet, and the following process is skipped, and all other processes in the main routine are executed.

If NE≧500 rpm, it is determined that the engine is starting, and the process proceeds to the first step 61. In step 61, it is determined whether a flag FLGi indicating whether the following steps 62 to 64 have been executed once after starting the engine is set to II III. If FLG, = 1, the following step 62
~64 Full jump °C Proceed to other processing in the main routine, and if FLG,=O, proceed to step 62. In step 62, the cooling water temperature THWE immediately before the previous engine operation stop stored in the backup RAM 44 and TH
The correction amount △5t is stored in the RAM 42 as t'L''c based on the difference from the cooling water temperature THW at the start of the engine after decoy.
Ask for ep'. ROM46 also contains (THWE-T
A function table of △5tep for HW) is prepared.
Then, in step 62, C.DELTA.5tep is determined from this function table using the interpolation method. Next step 63
Now, to this correction amount, the minimum value of s top △3jep g
lil+ is calculated from 2 as ΔS tep rrwr =Δ5tep−. However, K2 is a constant of 2<1.0. Next, in the steering knob 64, the flag FLG is set to 1.
As a result, as long as the engine continues to operate, the steering knobs 62 to 64 are not executed. Note that the flag FLG is reset to FLG,=O in an initial processing routine before starting the engine.

FIG. 5 shows an interrupt processing routine that is executed when A/D conversion regarding the cooling water temperature THW is completed.
4 is stored. Therefore, when the engine stops, the cooling water temperature immediately before that stop will be stored as THWE. First, in step 70, it is determined whether steps 62 to 64 of the routine shown in FIG. 4 have been completed. This is done before performing steps 62-64.
This is because it would be bad to update i. Only when FLG, = 1, the process proceeds to step 71, and the T in the backup RAM 44 is
Update HWE to THW. Next step 72 and 7
3 is to control -THWE always more than THWE. This is when one engine stops when it is cold - THWE
This is done in order to prevent Δ5tep from being set to an undesirable value at the next startup due to being set low.

FIG. 6 shows a part of the interrupt processing routine that is executed at fixed time intervals or at fixed crank angle intervals, whereby Δ5 tep is gradually reduced to Δ3 tep ynia after starting. At step 80 (ri, △5tep
is reduced by 1 to a constant value. That is, △5tep
The process ←/\5tep -K is performed. In the next steps 81 and 82, △5tep t△5tep yn
control more than in.

Therefore, △5tep becomes a relatively large value obtained in step 62 of FIG.
Minimum value △5tep rr found in step 63 in the figure
It's beautiful to be in.

FIG. 7 shows a part of the processing provided in the middle of the main routine, in which the control value 5TEP of the valve control motor 18 is formed. In step 9o, the current cooling water temperature THW
It is determined whether or not the temperature is 80°C or higher. THW≧80℃
In the case of , it is assumed that the warm-up has been completed, and the process proceeds to step 91 where the control value 5TEP is set using the normal closed loop.
I'm looking for it. On the other hand, if THW<80°C, it is assumed that it is being warmed up, and the control value 5TEP is calculated as follows fL
Idle speed control is performed in the oven loop. In step 92, a control amount 5tep for the cooling water temperature THW is determined. 5top for THW in ROM46
A function table is provided.

In step 92, from this function table, 5
tep is required. Next, in step 93, the final control value 5TEP is set to the above-mentioned 5tep and Δ5tep.
Further, the correction amount α is determined as follows from other correction amounts α, such as correction amounts based on whether the air conditioner is turned on or off or correction amounts based on the shift position of the automatic shift transmission.

S TEP '-5tep+△5tep+α The valve control motor 18 is driven according to the control value 5TEP obtained in this way, and intake air at a flow rate corresponding to this 5TEP is supplied to the engine via the bypass intake passage 14. and the idle rotation speed is controlled.

As described above, according to this embodiment, △5tep is determined in degrees Celsius according to the difference between the cooling water temperature immediately before the previous operation stop and the cooling water temperature immediately after the current start-up, and the larger the difference, the thicker the △5tep becomes. determined to be heard. Also, immediately after starting, △5tep becomes a relatively large value, and then immediately changes to 5tep.
It is decreased according to time or the rotation of the crankshaft until it reaches tep, and thereafter it is maintained at this △5tep line.

Generally, the friction of the engine is extremely large immediately after starting, so Δ5tsp is set large and the intake flow rate is controlled so as to decrease thereafter. After step 11, -friction changes depending on the oil temperature, so the difference between the cooling water temperature immediately before the engine stops and the cooling water temperature immediately after the next engine start, which is considered to be a substitute for this oil temperature, is the difference between the engine stoppage and the engine stoppage. The intake air flow rate is controlled by a value △3t6pvrin that corresponds to the amount of decrease in the water temperature inside.

As explained in detail above, according to the present invention, it is possible to control the idle rotation speed during warm-up to the optimum value at that time without additionally providing a special mechanism such as an oil temperature sensor. Become.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a schematic block diagram of an embodiment of the present invention, Fig. 3 is a block diagram mainly showing the second control path, Figs. 6 and 7 are flowcharts of part of the control program of the digital computer. 10... Intake passage, 12... Throttle valve, 14... Bypass intake passage, 16...
-・Control valve, 18... Valve control motor, 20・
... Drive circuit, 24 ... Control circuit, 26
...Cooling water temperature sensor. 30...Crank angle sensor, 40...C
P.U. 42...RAM, 44...Back amplifier RAM. 46...ROM0 Patent Applicant Toyota Motor Corporation Patent Application Representative Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Akira Yamaguchi Figure 6-25-

Claims (1)

[Claims] 1. A means for detecting the engine cooling water temperature, a means for storing all the cooling water temperatures detected immediately before the engine stops operating, and a cooling water temperature detected at the start of the engine shift and the cooling water stored in the storage means. A means for requesting a correction amount according to the difference from the temperature;
An idle rotation speed control device for an internal combustion engine, comprising means for fully adjusting an intake air flow rate during engine idling in accordance with the correction amount.