JPH0759926B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine, and more specifically, controls ignition timing so that the engine rotation speed approaches a target idle rotation speed in a predetermined idle operation state. The present invention relates to an ignition timing control device having a function to perform.

<Prior Art> Such an ignition timing control device has hitherto been disclosed in JP-A-62-13.
There are those as disclosed in Japanese Patent No. 5640 and Japanese Patent Laid-Open No. 57-83665.

This is to calculate the deviation between the target idle rotation speed and the actual rotation speed in a predetermined idle operation state,
According to this deviation, a preset ignition timing correction control value (advance or retard correction amount of the ignition timing) is searched for and obtained, and the ignition timing is corrected and controlled based on this correction control value. When the engine speed is higher than the target idle speed, the ignition timing is retarded to reduce the engine output, and when the engine speed is lower than the target idle speed, the engine is advanced to increase the engine output. Then, such ignition timing control and feedback control of idle rotation speed by adjusting the amount of auxiliary air supplied by bypassing the throttle valve are used together to improve idle stability.

<Problems to be Solved by the Invention> By the way, as shown in FIG. 4, under the condition of performing idle speed control by ignition timing control (for example, the throttle valve is fully closed), the clutch is engaged to start the vehicle. When the rotation speed decreases, the ignition timing advance control is performed to return this decrease in rotation speed to the target idle rotation speed, and the condition for controlling the idle rotation speed is removed (the throttle valve is opened. When the vehicle is started, the idle rotation speed control based on the ignition timing is canceled and the ignition timing is retarded until the ignition timing corresponds to the operating state after the vehicle starts.

However, in the ignition timing control, the variation range of the ignition timing is limited in order to prevent the ignition timing from largely fluctuating due to the output fluctuation of the air flow meter and to secure the stability during steady operation. , Is not promptly retarded from a large advance state immediately before starting appearing as a result of the idle speed control as described above to a desired ignition timing after starting, and a state advanced more than the desired ignition timing continues,
Knocking sometimes occurred when starting.

That is, if the difference between the desired ignition timing after starting and the final ignition timing at the time of idling is large because the variation range of the ignition timing is limited, it takes time until the desired ignition timing after starting is matched. There is a fear that the operability is deteriorated because the ignition is not performed at the ignition timing suitable for the operating condition.

The present invention has been made in view of the above problems, and enables a quick transition from the state in which the idle speed is controlled by the ignition timing to the normal ignition timing.
The purpose is to prevent knocking when starting.

<Means for Solving the Problem> Therefore, in the present invention, as shown in FIG. 1, an engine operating state detecting means for detecting an engine operating state including at least the engine speed, and an engine operating state detecting means for detecting the engine operating state detecting means. The basic ignition timing setting means for setting the basic ignition timing based on the engine operating state, and the ignition timing comparing the ignition timing newly set by the basic ignition timing setting means with the ignition timing actually ignited last time. The ignition timing setting means for setting the ignition timing of this time by limiting the variation width to within the predetermined limit value, the idle operating state detecting means for detecting the predetermined idle operating state, and the idle operating state detecting means. Ignition timing correction means for correcting the ignition timing so that the engine rotation speed approaches a target idle rotation speed in a predetermined detected idle operating state; In an ignition timing control device for an internal combustion engine, comprising: an ignition signal output means for outputting an ignition signal to an ignition device at the ignition timing set by the ignition timing setting means or the ignition timing corrected by the ignition timing correction means, The change limit value increasing means is provided for increasing the predetermined limit value in the ignition timing setting means for a predetermined period after the predetermined idle operation state in which the ignition timing is corrected by the ignition timing correction means is exited.

<Operation> The basic ignition timing setting means sets the basic ignition timing on the basis of the period operating state detected by the period operating state detecting means. Then, the ignition timing setting means compares the basic ignition timing newly set by the basic ignition timing setting means with the ignition timing that was actually ignited last time so that the variation range of the ignition timing is within a predetermined limit value. Limit and set this ignition timing. That is, even if the basic ignition timing setting means sets an ignition timing that is greatly advanced or retarded from the previous time, the ignition timing setting means sets the ignition timing by changing the ignition timing within an allowable range.

On the other hand, the ignition timing correction means corrects the ignition timing by advancing or retarding the ignition timing so that the engine rotation speed in the predetermined idle operation state detected by the idle operation state detection means approaches the target idle rotation speed.

The ignition signal output means outputs an ignition signal to the ignition device at the ignition timing corrected by the ignition timing correction means in the predetermined idle operation state, and the ignition timing setting means in the predetermined idle operation state. An ignition signal is output to the ignition device at the set ignition timing.

Here, the change limit value increasing means limits the change of the ignition timing for a predetermined period after the predetermined idle operation state in which the ignition timing is corrected according to the rotation speed by the ignition timing correcting means. Since the width is increased, the ignition timing can be changed in a larger step than in the normal state. That is, when shifting from the state where the idle rotation speed is controlled to the target idle rotation speed by the ignition timing advance / retard control to the ignition timing control according to the normal period operating state, the ignition timing can be swiftly shifted. As described above, the restriction is relaxed (or the restriction is invalidated).

<Example> An example of the present invention will be described below.

In FIG. 2, the intake passage 2 of the engine 1 is provided with an air flow meter 3 for detecting an intake air flow rate Q, and an idle switch 5 which is turned on at a fully closed position (idle position) of a throttle valve 4, These detection signals are input to the control unit 6 containing a microcomputer. Further, the engine 1 is provided with an electromagnetic fuel injection valve 7 for each cylinder. These fuel injection valves 7 are driven to open / close by an injection pulse signal output from the control unit 6 in correspondence with the fuel injection amount, and inject fuel to the engine 1.

An ignition plug 8 is provided in each cylinder of the engine 1.
The high voltage generated in the ignition coil 9 is sequentially applied to the spark plugs 8 through the distributor 10, whereby spark ignition is performed to ignite and burn the air-fuel mixture. Here, the ignition coil 9 is controlled in timing of generation of a high voltage via a power transistor 11 attached thereto. The ignition timing is controlled by controlling the ON / OFF timing of the power transistor 11 with the ignition signal from the control unit 6 which also serves as the ignition signal output means. In this example,
The ignition device comprises the spark plug 8, the ignition coil 9, the distributor 10, and the power transistor 11.

The distributor 10 has a built-in photoelectric crank angle sensor 12. The crank angle sensor 12 includes a signal disk plate 14 that rotates integrally with the distributor shaft 13, and a detection unit 15. The signal disc plate 14 is provided with 180 position signal (2 ° signal) slits 16 and four reference crank angle signal (180 ° signal) slits 17 for four cylinders. One of the angle signal slits 17 is #
It is also used to identify one cylinder. The detection unit 15 detects the slits 16 and 17 and outputs a position signal and a reference crank angle signal including a cylinder discrimination signal to the control unit 6.
Output to. The engine speed N can be calculated by counting the number of outputs of the position signal per unit time or by measuring the cycle of the reference crank angle signal.

Further, in the auxiliary air passage 19 that bypasses the throttle valve 4, an idle control valve 18 for controlling the amount of auxiliary air to control the engine speed N during idle operation to a target speed.
Is provided. The idle control valve 18 is a rotary type, and the drive pulse signals from the control unit 6 are sent to the valve opening coil and the valve closing coil (not shown) in a state where they are mutually inverted. The opening is controlled according to the duty ratio (ON time ratio of the valve opening coil).

In the figure, 20 is an air cleaner, 21 is a water temperature sensor that detects the cooling water temperature of the engine 1, 22 is a neutral switch that is turned on when the transmission attached to the engine 1 is in the neutral state, and 23 is a vehicle equipped with the engine 1. A vehicle speed sensor that detects the vehicle speed. In addition, the above idle switch 5,
The neutral switch 22 and the vehicle speed sensor 23 correspond to the idling operation state detecting means, and the air flow meter 3 and the crank angle sensor 12 correspond to the engine operating state detecting means.

Here, the idle control valve by the control unit 6
The drive control of 18 will be briefly described.

The control unit 6 is in a predetermined idle operation state, that is, the idle switch 5 is on and the neutral switch 22 is on, or the idle switch 5 is on and the vehicle speed detected by the vehicle speed sensor 23 is below a predetermined value. Sometimes, the target idle speed Ns and the actual engine speed N
When the actual engine speed N is lower than the target idle speed Ns, the duty ratio is increased by a predetermined value to increase the opening degree of the idle control valve 18, while the actual engine speed N is increased. Is higher than the target idle rotation speed Ns, the duty ratio is reduced by a predetermined value to reduce the opening degree of the idle control valve 18 to control the actual engine rotation speed N to the target idle rotation speed Ns.

Next, the ignition timing control by the control unit 6 including the ignition timing control based on the deviation between the actual engine rotation speed N and the target idle rotation speed Ns in the predetermined idle operation state will be described with reference to the flowchart of FIG.

In this embodiment, the control unit 6 is provided with the functions of a basic ignition timing setting means, an ignition timing setting means, an ignition timing correcting means, and a change limit value increasing means by software as shown in the flow chart of FIG. There is.

In step 1 (denoted as S1 in the drawing; the same applies hereinafter), the engine speed N calculated based on the signal from the crank angle sensor 12, the intake air flow rate Q detected by the air flow meter 3, and the water temperature. The cooling water temperature Tw detected by the sensor 21 is input.

The switch 2 uses the basic fuel injection amount Tp that indicates the engine load state.
(← K × Q / N; K is a constant) is calculated. Since the basic fuel injection amount Tp is a value used for fuel injection amount control,
The value calculated by the fuel injection amount control routine may be read.

In step 3, from the map of the basic ignition timing ADV ₀ which is set in advance with the basic fuel injection amount Tp and the engine speed N as parameters, the basic ignition corresponding to the current engine speed N and the basic fuel injection amount Tp is performed. Data of time ADV ₀ (a value indicating the number of crank angle before the top dead center) is obtained by searching.

In step 4, it is determined whether the current engine operating state is a predetermined idle operating state. The predetermined idle operation state means that the idle switch 5 is ON and the neutral switch 22 is ON, or the idle switch 5 is ON and the vehicle speed sensor 23 detects the same as when the auxiliary air amount is controlled by the idle control valve 18. This is when the vehicle speed is equal to or less than a predetermined value.

Here, when it is determined that the engine is in the predetermined idle operation state, the routine proceeds to step 5, where the target idle rotation speed Ns and the actual engine rotation speed N set according to the cooling water temperature Tw detected by the water temperature sensor 21 are set. Deviation ΔN of
In the next step 6, the correction value ADV _h of the ignition timing ADV is set according to this deviation ΔN. That is, when the actual engine speed N is higher than the target idle speed Ns, a larger retard correction value ADV _h is set according to the absolute value of the deviation ΔN, while the actual engine speed N is set to the target value. when below the idle rotational speed Ns is set larger advance angle correction value ADV _h in accordance with the absolute value of the deviation .DELTA.N.

Then, in step 7, the final ignition timing ADV is set by adding (for advance angle correction) or subtracting (for retard angle correction) the correction value set in step 6 to the basic ignition timing ADV _0. When the engine rotation speed N is lower than the target, the advance angle is corrected to increase the engine output to increase the rotation speed,
When the actual engine speed N is higher than the target, the engine angle is controlled to be close to the target idle speed Ns by retarding the engine output to reduce the engine output and lowering the engine speed. In this way, if the engine speed N is made to approach the target idle speed Ns by retarding / advancing the ignition timing ADV, the auxiliary air amount control by the idle control valve 18 can be used together. The idle rotation speed can be controlled in a flexible manner, and the idle rotation speed can be stabilized.

On the other hand, when it is determined in step 4 that the engine 1 is not in the predetermined idle operation state in which the idle speed control is performed by the ignition timing correction, first, in step 8, the predetermined idle operation state is exited and then within a predetermined time. Determine if there is.

Here, when it is determined that it is within the predetermined time after leaving the predetermined idle operation state and the idle rotation speed control by the ignition timing correction is being performed until immediately before,
Proceeding to step 9, as the ignition timing limiter ΔADV (limit value during ignition timing change) that limits the variation range of the ignition timing ADV, the normal value ΔADV ₁ is multiplied by a predetermined coefficient k to set a value that has been increased and corrected. Also allow for large changes in ignition timing ADV.

On the other hand, when it is determined in step 8 that it is not within the predetermined time after the predetermined idle operation state is exited, and a sufficient time has elapsed from the predetermined idle operation state in which the idle rotation speed control by the ignition timing correction is performed. Step 10
To the normal value ΔADV as the ignition timing limiter ΔADV.
Set to ₁ .

Then, in step 11, the absolute value of the deviation between the ignition timing ADV _-1 which was actually subjected to the previous ignition process and the basic ignition timing ADV ₀ set in step 3 this time, and the ignition timing set in step 9 or step 10 The limiter ΔADV is subcutaneously injected to determine whether or not the variation range of the ignition timing ADV exceeds the ignition timing limiter ΔADV.

Here, the basic ignition timing ADV ₀ set in step 3 this time
When it is determined that is changing from the previous ignition timing ADV _-1 over the ignition timing limiter ΔADV, the routine proceeds to step 13. In step 13, when the basic ignition timing ADV ₀ set in step 3 this time is changing to the advance side beyond the ignition timing limiter ΔADV, the ignition timing limiter ΔADV is added to the previous ignition timing ADV _-1. When the final ignition timing ADV is set and the basic ignition timing ADV ₀ set in step 3 this time is changing to the retard side beyond the ignition timing limiter ΔADV, the previous ignition timing ADV _-1 is set. Ignition timing limiter ΔADV is subtracted to set the final ignition timing ADV,
Make sure that the variation range of the ignition timing ADV is within the ignition timing limiter ΔADV.

On the other hand, when it is determined in step 11 that the basic ignition timing ADV ₀ set in step 3 this time has changed within the ignition timing limiter ΔADV from the previous ignition timing ADV _-1 ,
Proceeding to step 12, the basic ignition timing ADV ₀ set in step 3 this time is set as the final ignition timing ADV.

When the ignition timing ADV is set in this way, the ON timing of the power transistor 11 (calculated back from the ignition timing ADV and the required energization time) is measured using the reference crank angle signal from the crank angle sensor 12 as a measurement reference. At a predetermined time, the power transistor 11 is turned on to start energization of the ignition coil 9, and the ignition timing ADV (power transistor 11 is turned off) is also set using the reference crank angle signal as a measurement reference.
Timing), and when the ignition timing ADV is reached, the power transistor 11 is turned off to cut off the energization to the ignition coil 9 to generate a high voltage, and the high voltage is supplied to the ignition plug via the distributor 10. 8 by applying 8
The spark is ignited by and the mixture is ignited and burned.

As described above, in this embodiment, in the predetermined idle operation state, the ignition timing ADV is retarded / advanced so that the actual engine speed N approaches the target idle speed Ns.
Since the ignition timing limiter ΔADV is corrected to be increased more than usual within a predetermined time after exiting such an idle operation state, for example, the final ignition timing ADV in the predetermined idle operation state and the predetermined idle operation state are removed. Even if there is a large deviation from the required ignition timing ADV from, the ignition timing ADV can be changed with a large change range, so that the required ignition timing ADV can be promptly matched with the predetermined ignition timing ADV. The drivability can be improved by setting the ignition timing ADV when the engine 1 is started, that is, when the engine 1 is started, to a timing commensurate with the engine operating state.

In this embodiment, the ignition timing limiter ΔADV is increased by multiplying the ignition timing limiter ΔADV by the predetermined coefficient k. However, after the predetermined idle operation state is over, the predetermined engine sets the ignition timing limiter ΔADV to infinity. Effective ignition timing A
The range of DV change may not be regulated. In this case, it is possible to shift from the final ignition timing ADV in the predetermined idle operation state to the required ignition timing ADV after starting without any restriction.

Further, in the present embodiment, the ignition timing limiter ΔADV is increased within a predetermined time after leaving the predetermined idle operation state, but from the final ignition timing ADV in the predetermined idle operation state to the required ignition timing ADV after starting. The ignition timing limiter ΔADV may be increased until they match.

<Effects of the Invention> As described above, according to the present invention, the predetermined idle operation state in which the engine rotation speed is controlled so as to approach the target idle rotation speed by retarding / advancing the ignition timing is eliminated. Therefore, in the specified engine, the specified limit value that limits the variation range of the ignition timing is increased, so it is possible to change from the ignition timing that has been retarded / advanced for idle speed control to the normal ignition timing. As a result, it is possible to quickly shift, and it is possible to prevent knocking from occurring at the time of starting.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a system schematic diagram showing an embodiment of the present invention, and FIG. 3 is a flow chart showing the contents of ignition timing control in the same embodiment.
FIG. 4 is a time chart for explaining the problems of the conventional ignition timing control. 1 ... Engine, 3 ... Air flow meter, 4 ... Throttle valve, 5 ... Idle switch, 6 ... Control unit, 8 ... Spark plug, 9 ... Ignition coil, 10 ... Distributor, 11 ... Power Transistor, 12 …… Crank angle sensor, 22 …… Neutral switch, 23 ……
Vehicle speed sensor

Claims (1)

[Claims] 1. An engine operating state detecting means for detecting an engine operating state including at least an engine speed, and a basic ignition timing setting for setting a basic ignition timing based on the engine operating state detected by the engine operating state detecting means. Means and the ignition timing newly set by the basic ignition timing setting means and the ignition timing actually ignited last time are compared, and the variation range of the ignition timing is restricted to fall within a predetermined limit value. Ignition timing setting means for setting ignition timing, idle operating state detecting means for detecting a predetermined idle operating state, and engine rotation speed target idle rotational speed in a predetermined idle operating state detected by the idle operating state detecting means Ignition timing correction means for correcting the ignition timing so as to approach the ignition timing, and the ignition timing set by the ignition timing setting means or the ignition timing correction means. In an ignition timing control device for an internal combustion engine, which comprises an ignition signal output means for outputting an ignition signal to an ignition device at an ignition timing corrected by the means, a predetermined idle operation in which the ignition timing is corrected by the ignition timing correction means. An ignition timing control device for an internal combustion engine, comprising: a change limit value increasing means for increasing a predetermined limit value in the ignition timing setting means for a predetermined period after the state is exited.