JPS59119039A - Engine idling control device - Google Patents

Abstract

PURPOSE:To eliminate the engine speed fluctuation in the idling operation and to improve the fuel economy by disposing a by-pass air passage in parallel with a throttle valve in the air intake system, and disposing a pneumatic valve in said air passage which is opened at a timing synchronized with the intake stroke of respective cylinders. CONSTITUTION:A by-pass passage 19 is disposed in parallel with a throttle valve 14 in the air intake system, and an electropneumatic valve 20 is disposed in said air passage 19. A rotation angle signal form an electromagnetic pickup 23 is supplied to an engine control device 21 as a rotation speed discerning signal. Pulse signals from an electromagnetic pickup 26 are supplied to the engine control device as an intake stroke signal. The engine control device 21 compares a change in the engine speed with the average engine speed change, and controls the pneumatic valve's open-close time to bring it to the average engine speed change. Thus, speed change in the idling operation is eliminated, and a vehicle which is quiet and has a good fuel economy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine idle operation control device that stably controls the engine speed, particularly during low speed rotation.

In order to realize a car that is quiet and has good fuel efficiency, the idle speed of an automobile engine is set lower. In this case, fluctuations in the rotational speed that lead to discomfort during idle operation are also a serious problem.

Therefore, in an electronic fuel injection controlled engine in which each of a plurality of engine cylinders is provided with an electromagnetic fuel injection valve, it is required that the manufacturing tolerance of each electromagnetic injection valve be reduced to the limit.

However, even if they are made to exact precision at the time of manufacture, they are essentially powerless against changes over time and variations in the engine intake system.

This invention has been made in view of the above points, and is designed to eliminate rotational speed fluctuations caused by differences in fuel metering and intake conditions between cylinders, especially during low-speed rotation such as idling, and to eliminate low-speed rotational conditions. The purpose of the present invention is to provide an engine idle operation control device that makes it possible to realize a car that is stable, quiet, and has good fuel efficiency.

That is, in the idle operation control device according to the present invention, a bypass air passage is formed in parallel to the throttle valve of the intake system, and an air valve that is opened in synchronization with the intake stroke of each cylinder is provided in this air passage. Furthermore, the opening time of the air valve is controlled to be corrected so that the increase in rotational speed that occurs every time the engine explodes is equalized for all cylinders.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a four-cylinder spark ignition type engine 711 that electronically controls fuel injection. The air is guided to the intake manifold 15 via the throttle valve 14 and supplied to each air outlet of the engine 11. The exhaust gas from the engine 1 is discharged through an exhaust manifold 16 and an exhaust gas after-treatment device 17 such as a three-way catalytic reactor. An air-fuel ratio sensor 18 for detection is installed.

A bypass air passage 19 is formed in parallel with the throttle fl valve 14 of the intake thread, and this air passage 19
is provided with an air solenoid valve 20.

This air solenoid valve 20 is controlled to open by a command from an engine control device 21 including a computer, and when opened, forms an air passage that bypasses the suittor throttle valve 14.

A ring gear 22 that rotates integrally is provided on the crankshaft of the engine 11, and an electromagnetic pickup 23 is fixedly installed close to and facing the outer peripheral surface of the ring gear 22, thereby forming a rotation detection mechanism. For example, the ring gear 2
By forming protruding teeth on 2, the electromagnetic big
The rotation angle signal from the electromagnetic pickup 23 is supplied to the engine control device 21 as a rotation speed determination signal.

Also, like the ignition distributor 24, the engine 1
A disk 25 having one protrusion on the outer periphery is provided on the shaft that rotates once every two rotations, and an electromagnetic pickup 26 is fixedly installed at a position adjacent to the rotation surface of the disk 25. The position of the protrusion on the disc 25 is set at an angle so that it passes close to the electromagnetic pickup 26 just before the intake stroke of the one cylinder to be added (for example, the first cylinder). Immediately before the intake stroke of the first cylinder, one pulse signal is generated from the electromagnetic pickup 26.

This pulse signal is supplied to the engine control device 2.

In this engine control device j11.21, the intake air amount signal from the intake air amount detector 13, the t4iki pickup 2
The optimum fuel injection amount is calculated based on the rotational speed signal from 3, the signal from the air-fuel ratio sensor 18, etc., and the opening amount is set for each of the electromagnetic fuel injection valves 271 to 27d corresponding to each cylinder of the engine 11. A drive signal is provided to control the valve time, that is, the amount of shot per shell. In other words, the fuel injection control is always optimally controlled in accordance with the request of the engine 11 ◇ Also, the engine control device 21 controls the throttle valve 14
A valve opening command is given to the air solenoid valve 20 of the bypass air passage 19 for each intake stroke of each cylinder of the engine 11. The valve opening time at this time is set by calculation in the engine control # device 21 in the same way as above, and the bypass air passage is controlled so as to equalize the engine rotation speed due to one explosion corresponding to each cylinder. 0 Figure 2 shows the air solenoid valve 2 that opens and closes the bypass air passage 19.
0 shows a specific configuration example in which a stator 31 is held by a housing 30 and a valve seat 32 is caulked and secured.
The electromagnetic coil 33 is supplied with a nozzle down driving current having a width of i+le corresponding to the valve opening time from the engine control device 21. A movable core 34 is provided at the center of the. This core 34 is attracted when an excitation current is supplied to the electromagnetic coil 33, and a magnetic attraction force 35 is applied to the movable core 34 to resist the magnetic attraction force. The movable core 34 is integrally provided with a needle valve 36 and a valve seat 32 for sealing the valve seat 32 against the needle valve 36.

That is, when no excitation current is supplied to the electromagnetic coil 33, the valve seat 37 closes the seat portion of the valve seat 32 due to the force of the spring 35, and the air passages 19a, 19b are closed.
A @ between. Then, by supplying an excitation current and driving the movable core 34 against the spring 35, the air passages 19a and J9b are communicated with each other, and the bypass air passage 19 is formed.

Here, the response of this air solenoid valve 20 is 1/2 during idling operation at 600 revolutions per minute.
It is sufficient that the frequency response is enough to complete the opening/closing operation twice in rotation, that is, 50 msec (20 Hz) and 4 degrees. Also,
The amount of flow that passes through when the valve is opened should be extremely small, and it may be constructed of a simple type that is generally used for engine negative pressure control.

4-cylinder engine sequence chart 1, (4) in Figure 3
It becomes as shown in . Here, it is known that one cylinder performs one cycle of four strokes of "intake,""compression,""explosion," and "exhaust" during two revolutions of the ennon (720° C.). Similarly, in this (4) figure, the cylinder numbers shown as +1 to 4'4 are shown without regard to the ignition order of a normal 4-cylinder engine for the convenience of explanation, and here ≠ 1
The following explanation will be given assuming that the cycles proceed in the order of steps 4 to 4.

In the engine 1, 1il, from the magnetic pickup 26, just before the intake stroke of the first cylinder, the (
A signal shown in B) (referred to as G signal) is generated. In addition, from the electromagnetic pick-up roller f23, as shown in <C> in Figure 3, every 2 ink angles of the engine 1゛1. A pulse-shaped detection signal is obtained, and by counting this /4' pulse signal or measuring the pulse interval time, the engine control device 21 detects the instantaneous engine rotation speed and a specific crank angle. . By frequency-voltage conversion of the detection pulse signal from the electromagnetic pickup 23 by the control device 21, a rotational speed signal as shown in FIG. 3(D) can be obtained.

This engine speed, especially during low-speed rotation during idling, increases periodically during the engine's explosion stroke and then decreases during the latter half of the compression stroke of the cylinder that explodes. If the periodic variation widths ΔN1 to ΔN4 of the rotational speed are non-uniform as shown in Figure (2), this causes discomfort.

Here, the solenoid valve 2o that opens and closes the air passage 19 that bypasses the throttle valve 14 is controlled to open in accordance with the intake stroke of each cylinder as described above, and is shown in FIG.
As shown in (g), a valve opening command is given using a rectangular waveform signal such that TI=T2=T3=T4 in the initial state. However, if the opening of the stain magnetic valve 20 is controlled using a uniform valve opening time as shown in FIG. If the rotational speed oscillation amplitudes ΔN1 to ΔN4 corresponding to the explosion of the cylinders are uneven, it will cause discomfort to the driver.

Therefore, in this implementation I+u, the control device 21 reads the rotation speed NLs before the explosion and the rotation speed NH after the explosion, paying attention to the rotation speed fluctuation due to combustion for each cylinder shown in FIG. "NH-NL=ΔNil is determined for each cylinder.Then, the rotational speed difference ΔN+ in this one cylinder is
Compare it with the average value ΔN of the rotational speed difference in the previous four combustion strokes, and if it is "ΔNi ) ΔN", it is determined that the generated torque is excessive in the explosion of the above one cylinder, and the air electromagnetic force in the next intake stroke of the cylinder concerned is determined to be excessive. Control the valve opening time of the valve 20 to be short ◇ Conversely, if "ΔNi (ΔN"), the valve opening time of the xi valve 2o in the next intake stroke of the relevant cylinder is extended.

That is, when the air electromagnetic valve 20 is opened for a long time, the negative pressure in the intake manifold during the intake stroke of the corresponding cylinder is small, that is, close to atmospheric pressure, and the amount of air sucked into the cylinder increases. Conversely, when the opening time of the electromagnetic valve 20 becomes shorter, the weight of intake air decreases in the intake stroke of the corresponding cylinder.

In reality, it is not preferable to modify the pulse widths T1 to T4 of the valve opening command for the air electromagnetic valve 20 if the pulse widths T1 to T4 are changed greatly all at once, as this will result in sudden torque fluctuations. Therefore, once per cycle of the engine 11, the extremely small time Δ
The pulse width is controlled to increase or decrease by T, and this is successively repeated so that it approaches "ΔN1 = ΔN". As a result, the control pulse signal for the valve opening command of the air solenoid valve 20 is modified to absorb the rotational fluctuation of the engine 1, as shown in Fig. 3, and the engine rotational speed for each combustion of each cylinder is The number fluctuation range is also made uniform as shown in FIG. 3(G). In other words, the roughness of rotation that gives discomfort to the driver and the like is reduced.

Similarly, pressure changes within the intake manifold 15 propagate within the intake pipe almost at the speed of sound. Therefore, even if the valve opening control of the air electromagnetic valve 20 is executed in real time for the intake stroke of each cylinder, a failure such as a shift in the control point leading to a no-step will not occur.

FIG. 4 shows the flow of the above-mentioned control operation processing executed by the computer section in the engine control device 21. As shown in FIG. This process is interrupted every time the G signal shown in FIG. 3B is input and every time 180° of crank angle elapses after the G signal is generated.

First, the interrupt process for each G signal will be explained. When the G signal interrupt starts, "1" is written to the cylinder recognition number j of the intake stroke in step 101.

This indicates that the cylinder that enters the intake stroke immediately after the G signal is generated is the first cylinder. Therefore, in step 102, the valve opening time of "j = 1" is stored in the RAM storage area. Read data T, that is, Tj. Then, this Tj is set to the valve opening control output/arm pulse width value T of the air solenoid valve 20. Then, the air solenoid valve 20 is driven to open at the same time as the interruption of the G-go, for example, and is then controlled to close when a time period T1 has elapsed.

Here, T1 is a value that has already been corrected for the rotational speed fluctuation caused by the previous combustion in the first cylinder.

Next, in step 103, the explosion cylinder identification number is set to “3”.
”. This is because, as is clear from FIG. 3, during the intake stroke of the first cylinder, the third cylinder is in the explosion stroke.

Then, in steps 104 and 105, the instantaneous rotational speeds NL and NH before and after the explosion are read, and in step 106, [ΔN1=NHNJ■ calculation is performed to determine the rotational speed due to the current explosion stroke (third cylinder). The fluctuation range ΔNl is determined and this ΔNi is stored and set in the RAM.Furthermore, in step 107, the fluctuation range ΔN corresponding to each cylinder is calculated.
The average value of 1 to ΔN4 is determined to obtain ΔN. Here, the fluctuation ranges ΔN1 to ΔN4 corresponding to each cylinder have already been updated in step 106 as the new ΔN3 or the latest value that changed due to the explosion of the third cylinder, and the pond is also updated to the latest value. It is determined using the four information @ corresponding to each of the four cylinders.

Next, in step 10B, the rotational speed fluctuation Δ due to this explosion is
Compare N3 with the average value Δ obtained in step 107,
“If Δn=ΔN, 9J, time 1 crystal data T in RAM
Proceed to step 109 to leave 3 as is, and select “Δ
If ΔN3, the minute time ΔT is subtracted from the data T3 in the RAM in step 110, and conversely, if ΔN>ΔN3, ΔT is added to the data T3 in step 11.

The data T3 rewritten here is output as the control pulse i4 of the air solenoid valve 20 in the next next interrupt process.

The interrupt processing following the interrupt corresponding to this G signal is performed every 180° crank angle after the G signal, and in response to this interrupt, the suction root cylinder identification number j is Add "1" to. The value of this j becomes "2" at the next interrupt, and then r3Jr4J! ; and changes back to "1".

Now, 360 degrees after the G signal corresponding to the intake stroke of the third cylinder
To explain the case of crank angle interrupt processing in sequence, since j is "3" in Stella f114, the current control pulse Tj of the air solenoid valve 2o is T3. Then, in step 115, this is set as output data T, and in step 116, the recognition signal l of the cylinder that will explode this time is updated. Since [t=4] at the time of the previous interrupt, this time it is set as "1=5J" with "1←Rose+1" in step 116. However,
In this case, it is an f'i 4-cylinder engine, so step 1
At 17, judge whether 1 exceeds "4" or not, "1≦4"
If so, proceed directly to step 104, and if "1>4", proceed to step 118 to set "l4-j←4", specifically, if "i = 5 J, then ri = 1j (first cylinder)
Similarly, the process is transferred to Stella f104, and the same processing as that for the G signal interrupt described above is performed.

As described above, according to the present invention, in the idle operating state, that is, the state where the throttle valve is closed,
The bypass air passage formed for this throttle FjD valve is designed to fly in response to the intake stroke of each cylinder, and the time width during which it is opened corresponds to the rotation speed fluctuation due to the explosion corresponding to each cylinder of the engine. Now controlled by width. Therefore, it is possible to uniformly set the range of rotational speed fluctuations during the explosion stroke of each cylinder, so that the engine speed can be smoothly set without causing discomfort to the driver, especially during low-speed idling operation. This makes it possible to obtain accurate idle rotation.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an idle operation control device according to an embodiment of the present invention, FIG. 2 is a sectional block diagram showing an example of an air solenoid valve used in the above embodiment, and FIG. FIG. 4 is a modified diagram illustrating the operating state of the operation control device, and FIG. 4 is a flowchart similarly illustrating the control state. 11...engine, 13..., intake air amount detector,
14... Throttle valve, 15... Intake manifold, 16... Exhaust manifold, 18... Air-fuel ratio sensor, 19... Bypass air passage, 20... Air solenoid valve, 21... Engine control cape display (including computer), 23...electromagnetic pickup (rotation angle determination signal),
26...Pagamemagnetic big azzo (specific cylinder intake stroke detection)
0

Claims (1)

[Claims] A bypass air passage provided in parallel with the throttle valve section of the engine intake system, an air valve that opens and closes this bypass air passage, and a means for controlling the opening and closing of this air valve in synchronization with the intake stroke of each cylinder of the engine. and a means for detecting the rotational speed fluctuation that occurs every 1'4 cycles corresponding to each cylinder of the engine, and comparing the rotational speed fluctuation obtained by this means with the average rotational speed fluctuation. An engine idle operation control device comprising: means for correcting and controlling the opening/closing time of the air valve so as to approximate the average variation.