JPH02191842A - Idle adjusting method for internal combustion engine - Google Patents

Abstract

PURPOSE:To facilitate idle adjustment holding an engine to a stable operational condition with a less fluctuation of engine speed by fixing a bypass valve in its operating amount to a predetermined value thereafter adjusting an idle adjusting means so that the engine speed agrees with the regular idle speed. CONSTITUTION:In idle adjusting time, ignition timing is fixed to a predetermined value different from the regular ignition advance timing preferably to a predetermined value delayed from the regular ignition advance timing, while a bypass valve 14 is fixed in its operating amount to a predetermined value in accordance with a change amount of engine speed changing when the ignition timing is changed to the predetermined value from the regular ignition advance timing. Accordingly, an engine speed in this time is held to a speed approximate to the regular idle speed, stabilizing operation of an engine. Under this condition, an idle adjusting means 12 is adjusted to an adjusting speed equal to the idle speed. Consequently, the adjusting speed is equal to the idle speed easy to remember while facilitating adjustment, and the speed is difficult to be replaced with another speed value.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for adjusting the idle of an internal combustion engine.

(Prior art) A bypass passage that bypasses the throttle valve of an internal combustion engine and a bypass valve that adjusts the air flow rate in this passage are provided, and the bypass valve adjusts the air flow rate in this passage according to the deviation between the target idle rotation speed and the actual engine rotation speed when the engine is idling. There is known an idle speed control device that opens and closes a bypass valve to feedback control the engine speed to near a target idle speed.

When an internal combustion engine equipped with such an idle speed control device is shipped or maintained, if an attempt is made to adjust the idle speed by adjusting the bypass adjustment screw or throttle adjustment screw, the idle speed control device will adjust the engine speed. Since the bypass valve is opened and closed to maintain the target idle rotation speed, it is impossible to adjust the idle rotation speed under such circumstances. Therefore, when adjusting the idle speed, it is necessary to fix the output of the idle speed control device, open the bypass valve to a predetermined degree or fully close it, and operate the engine in a constant operating state.

On the other hand, it is necessary to adjust the ignition timing when shipping or servicing the engine.In an internal combustion engine equipped with an ignition timing control device that electronically controls the ignition timing, the ignition timing is fixed at a predetermined value during idling operation. While monitoring with a timing light, the distributor housing is rotated and adjusted so that the ignition timing adjustment pulley engraved on the crank pulley matches the indicator bin (generally called distributor swing adjustment). ).

(Problem to be solved by the invention) In many engines, the above-mentioned idle speed adjustment and ignition timing adjustment are performed separately. For example, first, the distributor oscillation adjustment is performed. Later, the idle speed is adjusted by increasing or decreasing the amount of idle air using a bypass adjustment screw. There is a problem in that performing the ignition timing adjustment and the idle rotation speed adjustment separately in this way is time-consuming.

Therefore, the valve opening degree of the bypass valve is fixed at a predetermined value, and the ignition timing is also fixed at a predetermined value. For example, Japanese Patent Application Laid-Open No. 56-52573 discloses a method of performing the "idle adjustment J" at the same time when referring to both adjustments.This conventional method is shown in FIG. To explain this, let us assume that the normal idle speed N5t (e.g. 800 rpm) to be controlled during standard idle operation in the normal mode is set and the normal ignition advance angle is set to IGst (e.g. 15° BTDC). Operating point B° in Figure 3), and when adjusting the idle (!II adjustment mode), fully close the bypass valve and set the ignition advance angle to a predetermined value ■co (for example, 5° BDC)
After setting the respective values, the bypass adjustment screw is adjusted so that the idle speed matches the normal idle speed NET mentioned above (operating point A in Fig. 3).
When these adjustments are completed and the engine returns to its normal operating state, the ignition advance angle is at the predetermined value IGO (5°).
Since the ignition advance angle is advanced from the normal ignition advance angle iCa5t (t5°), the engine speed increases by the amount of advance, and the idle speed increases to the normal idle speed Nsy (800rpm).
m) higher rotational speed NIl (e.g. 900 rpm
) (actuation point A° in Figure 3).

Therefore, in order to obtain the normal idle rotation speed Nut (800 rpm) in normal mode operation after adjustment, the idle rotation speed at the time of adjustment is set lower than the normal idle rotation speed Njy, taking into account the increase in rotation speed due to advance angle. Predetermined rotation speed NL
(for example, 700 r'pm) (operating point B in Figure 3).However, if the idle adjustment is performed at such a low idle speed, the rotation speed fluctuation will be large at low speeds. , it is difficult to make adjustments due to lack of stability, and it also has the disadvantage that it is easy to mistake the adjusted rotation speed because the normal idle rotation speed r'lsy during normal mode operation and the adjusted rotation speed NL during adjustment are different. .

The present invention was made to solve such problems,
To provide an idle adjustment method for an internal combustion engine that can maintain an engine in a stable operating state with little rotational fluctuation during idle adjustment and facilitates idle adjustment.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a bypass valve is disposed in a bypass passage that bypasses a throttle valve disposed in an intake passage; Equipped with an idle adjustment means that manually adjusts the amount of intake air when the valve and bypass valve are fully closed, and adjusts the ignition timing and engine speed to the normal ignition advance and normal idle speed, respectively, during standard idle operation. In the method for adjusting the idle of an internal combustion engine to be controlled, when adjusting the idle, the ignition timing is fixed at a predetermined value different from the normal ignition advance, and the operating amount of the bypass valve is adjusted to change the ignition timing to a predetermined value from the normal ignition advance. The internal combustion engine is characterized in that the idle adjustment means is adjusted so that the engine speed matches the normal idle speed after the engine speed is fixed at a predetermined value according to the amount of change in the engine speed that changes when the engine speed is changed to the specified value. An idle adjustment method is provided.

(Function) Generally, when the ignition timing is retarded, the engine speed decreases, but the engine operation becomes stable.The idle adjustment method of the present invention allows the ignition timing to be set to a predetermined value different from the normal ignition advance angle during idle adjustment. value, preferably a predetermined value retarded from the normal ignition advance angle, and the amount of operation of the bypass valve is adjusted according to the amount of rotational speed change that changes when the ignition timing is changed from the normal ignition advance angle to the predetermined value. is fixed at a predetermined value.

Therefore, the engine rotational speed at this time is maintained at a rotational speed close to the normal idle rotational speed, and the operation of the engine is stabilized. In this state, the engine speed is adjusted by the idle adjustment means to an adjusted speed that is the same value as the normal idle speed.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

The first factor shows the configuration of the idle speed adjusting device that implements the method of the present invention, and reference numeral 1 in the figure is, for example, a four-cylinder gasoline engine, each cylinder of this engine 1 is connected to an intake manifold 2, and an intake manifold 2 is connected to each cylinder of the engine 1. Manifold 2 is surge tank 2a
It is connected to the intake pipe 3 via. An air cleaner (not shown) is attached to the atmosphere opening end of the intake pipe 3, and a throttle valve 4 and an idle adjustment adjustment screw 5 for adjusting the air flow rate when the throttle valve 4 is fully closed are installed in the middle of the air cleaner. It is arranged. In addition, in the intake pipe 3,
Three bypass passages 6, 7 and 8 are connected from the upstream side of the throttle valve 4 to the downstream side thereof. A bypass adjustment screw 12 is disposed in the first bypass passage 6 to adjust the flow rate of bypass air for idle adjustment, which flows through the passage 6. A bypass valve 14 is disposed in the second bypass passage 7, and a bypass valve 14 is disposed in the second bypass passage 7. A temperature-sensitive type fast idle valve 15 that opens only when the engine is cold is provided in each of the bypass passages 8 .

The bypass valve 14 has a valve body 14 that closes the bypass passage 7.
a, a coil spring 14b that always biases the valve body 14a in the closing direction, and a solenoid 14 that opens the valve body 14a against the pressing force of the coil spring 14b when biased.
c. The solenoid 14c of this bypass valve 14 is connected to the electronic control device 10. The bypass valve 14 is duty-controlled by a drive signal from the control device IO, and controls the idle rotation speed by regulating the bypass air flow rate flowing through the bypass passage 7 by tIN.

Note that the operating amount of the bypass valve 14 that is duty-controlled is defined by a duty rate, and bypass air according to the duty rate is supplied to the engine l.

The first idle valve 15 is preferably of wax type, for example, and is supplied with cooling water that has cooled the engine 1. The fast idle valve 15 opens and closes the bypass passage 8 with a valve body 15a that expands and contracts according to the temperature of the cooling water. When the temperature of the cooling water exceeds a predetermined value, the valve body 15a completely blocks the bypass passage 8, Below, the bypass passage 8 is opened according to the water temperature, the amount of bypass air to the engine 1 is increased, the idle speed is increased, and the idle operation during cold conditions is stabilized.

Each cylinder 1a of the engine 1 is provided with a spark plug 9 that ignites the air-fuel mixture in the cylinder 1a. It is connected to the output side of 10. The drive surface W11g supplies a primary voltage to the ignition coil 17 in response to a control signal supplied from the electronic control device 10, and the ignition coil 17 generates a secondary high voltage when the supply of the primary voltage is stopped.

A fuel injection valve 20 attached to the intake manifold 2 of each cylinder 1a is connected to the output side of the electronic control device 10, and is opened in response to a valve opening drive signal from the electronic control device 10 according to the intake air amount. The required amount of fuel is injected and supplied to each cylinder 1a. On the other hand, a changeover switch 11 is connected to the input side of the electronic control device 10. This changeover switch 11 is a manual switch for adjusting the idle of the engine l, and has a changeover contact piece 11a whose one end is grounded, and a contact point 11b.
It has This changeover switch 11 is provided, for example, in the housing of the electronic control device 10, and when an operator switches the changeover contact piece 11a to the contact point 11b side when adjusting the idle, the bypass air flow rate and ignition timing are set to a predetermined value. It generates an ON signal as a command signal to fix the value and supplies it to the electronic IllIlIm device 10.

Next, the operation of the idle speed adjusting device configured as described above will be explained below.

FIG. 2 is a flowchart of an idle adjustment routine showing a control procedure executed by the electronic control device 10 of the idle speed adjustment device shown in FIG.

The electronic control unit IO first determines whether or not the changeover switch 11 is turned on and an on signal to start idle adjustment is input (step 20), and if the determination result is negative (NO). , the electronic control unit IO is in step 2
2, normal ignition timing control and duty control of the bypass valve 14 in the normal mode are executed.

Duty control of the bypass valve 14 in the normal mode is performed, for example, as follows. t+m control device IO is
The operating state of the engine is detected by an engine rotation speed sensor, an engine water temperature sensor, an air conditioner switch, etc. (not shown), and a target idle rotation speed N is determined. At the same time, this target idle rotation speed N0. Calculate the deviation ΔN (-N, -N, .) between the actual engine speed N and the calculated deviation Δ
Set the duty rate according to N. On the other hand, when igniting M
T + a is also set according to the detected engine operating condition.

Then, the electronic control unit IO controls the operation of the bypass valve 14 and the drive circuit (power transistor circuit) 18 based on the duty factor and ignition timing T16 calculated in this way, and adjusts the engine rotation speed N.

is the target idle speed N. Stabilize nearby.

Next, after 61 meters have passed to ensure that the engine l has warmed up and is in a stable idling state with the first idle valve 15 fully closed, the mechanic will perform idle adjustment and ignition timing adjustment. When the changeover switch 11 is turned on, the electronic control unit IO determines that the determination in step 20 is affirmative (ves) due to the input of the on signal from the changeover step 311, and executes steps S24 and 326 to bypass the adjustment mode. An electronic control device 10 that controls the duty of the valve 14 and controls the ignition timing.
outputs a predetermined control signal to the drive circuit 18 in step 24, and sets the ignition timing to a predetermined value IG, which is suitable for performing idle adjustment and ignition timing adjustment.
For example, the duty ratio of the bypass valve 14 is set at step S26 using the following equation, and the bypass valve 14 is duty-controlled using this duty ratio.

DD, +ΔD Here, is a constant value and may be a duty rate of 0%, and ΔD is the standard idle operating state and the normal idle rotation speed N. When the ignition timing of an idle-adjusted engine that is operated at the normal ignition advance angle IGsv is set to the predetermined value IG at the time of adjustment described above, the engine speed is adjusted in response to the amount of change in the engine speed. This is a correction value necessary to maintain the normal idle rotation speed N air.

Here, the above-mentioned predetermined ignition timing IC, which is set at the time of idle adjustment, is usually set to a predetermined value on the retard side than the above-mentioned normal ignition advance angle IG*t in order to stabilize the engine speed at the time of adjustment. Ru. For this reason, the engine speed drops by the amount of retarding the ignition timing, but ΔD is set to a value that increases the amount of bypass air by the amount of this falling speed and keeps the engine speed constant. . Therefore, idle adjustment is performed by adjusting the ignition timing and bypass valve 14 as described above.
After fixing the duty rate of
The bypass adjustment screw 12 or the adjustment screw 5 may be adjusted so as to match the engine rotation speed (00 rpm). Since the number is stable, there is no rotation speed fluctuation, making adjustment easy. Furthermore, since the adjusted rotational speed is the same as the normal idle rotational speed NsT, it is easy to remember the adjusted rotational speed, and it is difficult to mistake it for another value.

Although the bypass air flow rate flowing through the bypass passage 7 is controlled by the duty rate of the bypass valve 14, the present invention is not limited to this, and the bypass air flow rate may also be adjusted using, for example, a pulse motor or a linear solenoid. Yes, the operating amount of the bypass valve in this case is defined by the amount of change in the valve body. Further, the bypass air flow rate may be adjusted by forcibly opening and closing the throttle valve in the vicinity of the fully closed position, in addition to the bypass valve 14 described above.

(Effects of the Invention) As detailed above, according to the idle speed adjustment device for an internal combustion engine of the present invention, when adjusting the idle, the ignition timing is set to a predetermined value different from the normal ignition advance angle IG, After correcting the bypass air amount by the amount corresponding to the amount of change in rotation speed that changes due to this ignition timing change setting, the idle adjustment means is adjusted so that the engine rotation speed matches the regular idle rotation speed. It is possible to stabilize the engine operation at the time, making adjustment easier, and
Since the adjusted rotation speed is the same as the regular idle rotation speed,
This provides various effects such as making it easy to remember the adjusted rotation speed and making it difficult to confuse it with another rotation value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an idle speed adjusting device that implements the method of the present invention, FIG. 2 is a flowchart showing the control procedure executed by the electronic control device 10 shown in FIG. 1, and FIG. 3 is an ignition It is a graph for explaining an operating line of engine rotation speed that changes with a change in timing. l... Engine, 4... Throttle valve, 5... Adjustment screw (idle adjustment means), 6.7...
Bypass passage, 9... Ignition plug, lO... Electronic control device, 11... Changeover switch, 12... Bypass adjustment screw (idle adjustment means), 14... Bypass valve, Lenoid valve (bypass valve) ), 15...control device, 18...drive circuit. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagado: 9LD *

Claims (1)

[Claims] A bypass valve is disposed in a bypass passage that bypasses a throttle valve disposed in the intake passage, and an idle adjustment means is provided for manually adjusting the amount of intake air when the throttle valve and the bypass valve are fully closed, In a method for adjusting the idle of an internal combustion engine in which the ignition timing and engine speed in a standard idle operating state are controlled to the normal ignition advance angle and the normal idle speed, respectively, the ignition timing is set to the normal ignition advance angle and the engine speed during idle adjustment. The operating amount of the bypass valve is fixed at a different predetermined value, and the operating amount of the bypass valve is fixed at a predetermined value corresponding to the amount of change in rotation speed that changes when the ignition timing is changed from the normal ignition advance angle to the predetermined value. An idle adjustment method for an internal combustion engine, characterized in that the idle adjustment means is adjusted so that the idle rotation speed matches the normal idle rotation speed.