JPH05126022A - Ignition timing control device in idling - Google Patents

Abstract

PURPOSE:To correct waving of the engine rotation frequency evenly by calculating a correcting amount asymmetrical at the advance side and the lag side of the ignition timing according to the deflection of the calculated engine rotation frequency, in the engine operating condition set at the nonlinear part near the torque peak. CONSTITUTION:The idle condition of an internal combustion engine 10 is detected in a detecting means 11, while the engine rotation frequency is detected in a rotation frequency detecting means 12. In a correcting amount calculating means, a correcting amount asymmetrical at the spark advance side and at the spark lag side of the ignition timing is calculated according to the deflection of the engine rotation frequency calculated by the second calculating means 14, at the engine operating condition in which the standard ignition timing calculated by the first calculating means 13 is set at a nonlinear part near the torque peak of the ignition timing torque property. Furthermore, in an ignition timing operation means 16, based on a correcting amount, a value to correct the standard ignition timing and to determine the ignition timing is output. Consequently, waviness of the engine rotation frequency can be corrected evenly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device during idling, and more particularly to an ignition timing control device for stabilizing the engine speed during idling of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, when the internal combustion engine is idle, the engine speed increases when the ignition timing is advanced under the condition that the throttle opening and the air-fuel ratio are constant, and the engine speed decreases when the ignition timing is delayed. In consideration of this characteristic, the engine speed at idle (idle speed) is compared with the target speed, and when the idle speed becomes lower than the target speed, the ignition timing is advanced, while the idle speed is the target speed. There is known an ignition timing control method for stabilizing the idle speed by delaying the ignition timing when it further rises (Japanese Patent Application Laid-Open No. 58-176470).

Further, in an internal combustion engine equipped with an automatic transmission,
When the shift position of the automatic transmission is selected to the neutral range or the parking range during idling, the ignition timing is controlled by the advance value determined according to the engine speed, and during idling, the drive range etc. An ignition timing control device that controls the ignition timing on the side of a certain angle advance from the above advance value when the range is selected is also conventionally known (JP-A-58-48775). .. Furthermore, an ignition timing control method has been conventionally known in which the correction amount of the ignition timing is determined according to the degree of increase or decrease of the engine speed when the internal combustion engine is idle (Japanese Patent Laid-Open No. 57-57).
-83665 gazette).

[0004]

Therefore, by combining the above conventional techniques, the ignition timing is corrected according to the degree of fluctuation of the engine speed when the internal combustion engine equipped with the automatic transmission is idle. In such a case, conventionally, the ignition timing in the neutral range or the parking range (hereinafter referred to as N range) is set to the position shown in FIG. 9A, and the shift position other than the above (hereinafter referred to as D range) is set. At this time, the ignition timing is set to the advance side with respect to that in the N range, as indicated by b in the figure. This is because if the ignition timing during idling is advanced, it is possible to improve fuel efficiency when the engine speed is constant, but on the other hand, if it advances too much, misfire tends to occur.
Further, since the vibration becomes large, in the N range in which this tendency is not significantly applied, the ignition timing is set relatively to the retard side a in consideration of the above-mentioned misfire and vibration.
Since the load is applied in the range, the combustion stabilizes.
Even if it is set to the advance side of the ignition timing of the range, there is little risk of misfire or vibration. Therefore, in consideration of the improvement of fuel efficiency, the ignition timing is set to b on the advance side of a in the D range. is there.

However, as shown in FIG. 9, in the N range, the set point a of the ignition timing is located on the substantially linear slope portion of the ignition timing vs. torque characteristic curve I, whereas D
In the range, the ignition timing set point b is located on a non-linear curve near the MBT (close to the torque peak) of the ignition timing versus torque characteristic curve II.

Therefore, in the N range, the torque increase amount TR when the ignition timing is corrected by a predetermined value from the set point a to the advance side
₁ and the absolute value of the torque decrease amount TR ₂ when the same predetermined value is corrected to the retard side from the set point a, the ignition timing is advanced from the set point b in the D range. There is a relatively large difference between the absolute value of the torque increase amount TR ₃ when a predetermined value is corrected to the angle side and the absolute value of the torque decrease amount TR ₄ when the same predetermined value is corrected to the retard angle side from the set point b. Will occur.

Therefore, in the D range, when the engine speed fluctuates during idling as shown by III in FIG. 10, conventionally, when the ignition timing control is carried out, the unbalance of the torque fluctuation range due to the above ignition timing correction causes Although the fluctuation amount of the engine speed can be suppressed as indicated by the one-dot chain line IV, the waviness of the engine speed cannot be uniformly corrected, and there is a problem that drivability is poor.

The present invention has been made in view of the above points, and the ignition timing correction at the time of idling which solves the above problems is made by making the ignition timing correction amount at the time of idling different between the advance side and the retard side. An object is to provide a control device.

[0009]

In order to achieve the above object, the present invention has a configuration as shown in the principle block diagram of FIG. In the figure, the detection means 11 detects the idle state of the internal combustion engine 10. The rotation speed detection means 12 detects the engine rotation speed of the internal combustion engine 10. Further, the first calculating means 13 calculates the basic ignition timing according to the engine state at the time of idling. The second calculating means 14 calculates the deviation between the engine speed detected by the speed detecting means 12 and the target speed during idling.

Further, the correction amount calculating means 15 is arranged so that the basic ignition timing calculated by the first calculating means 13 is set in a non-linear portion close to the torque peak of the ignition timing vs. torque characteristic, in the engine operating state, An asymmetrical correction amount is calculated between the advance side and the retard side of the ignition timing according to the deviation of the engine speed calculated by the second calculating means 14. Further, the ignition timing calculation means 16 corrects the basic ignition timing based on the correction amount calculated by the correction amount calculation means 15 and outputs a value that determines the ignition timing.

[0011]

According to the present invention, when the internal combustion engine 10 is idle, the absolute value of the correction amount for advancing the ignition timing is retarded by the correction amount calculation means 15 when the deviation between the engine speed and the target speed is the same. Based on the asymmetrical characteristics that are larger than the absolute value of the correction amount, the correction amount that retards the ignition timing is calculated when the engine speed rises above the target speed, and the engine speed becomes the target speed. When it further decreases, a correction amount for advancing the ignition timing is calculated.

Therefore, according to the present invention, the torque increase amount based on the correction amount that advances the ignition timing from the basic ignition timing to the advanced side by a predetermined value and the torque increase amount based on the correction amount that delays the ignition timing from the basic ignition timing to the advanced side by the same predetermined value as described above. It is possible to make the respective absolute values of the reduction amounts substantially the same.

[0013]

FIG. 2 shows a system configuration diagram of an embodiment of the present invention. This embodiment is an example in which a spark ignition type internal combustion engine (engine) is applied as the internal combustion engine 10. FIG. 2 shows a structural sectional view of an arbitrary cylinder, and an engine control computer (hereinafter referred to as an EFI computer) described later is shown. )
21 controls each part of the system.

In FIG. 2, an engine block 22 accommodates a piston 23 that reciprocates in the vertical direction in the figure, and a combustion chamber 24 communicates with an intake manifold 25 through an intake valve 26, while an exhaust valve 27. It is connected to the exhaust manifold 28 via.

An upstream side of the intake manifold 25 is connected to an intake pipe 31 via a surge tank 30 in common for all cylinders. Inside this intake pipe 31, the throttle valve 3
An air flow meter 32 is provided. The opening of the throttle valve 33 is adjusted in conjunction with the accelerator pedal, and the opening is detected by the throttle position sensor 34. The throttle position sensor 34 can detect whether or not the throttle valve 33 is fully closed, and constitutes the detecting means 11.

A bypass passage 35, which bypasses the throttle valve 33 and connects the upstream side and the downstream side of the throttle valve 33, is provided, and the bypass passage 35 is provided.
Idle speed control valve (ISC) whose opening degree is controlled by a solenoid
V) 36 is attached.

Reference numeral 37 denotes a fuel injection valve, which is provided in the EFI computer 2 which will be described later in the air flow passing through the intake manifold 25.
Inject fuel according to the instructions in 1. Further, the oxygen concentration detection sensor (O ₂ sensor) 38 is an exhaust manifold 2
It is provided so as to partially penetrate 8 and detects the oxygen concentration in the exhaust gas before entering the catalyst device 39. A water temperature sensor 40 is provided so as to penetrate the engine block 22 and partially project into the water jacket, and detects the water temperature of the engine cooling water. 41 is an igniter with a built-in ignition coil, which opens and closes the primary current.

Reference numeral 42 is a distributor, which is a cylinder discrimination sensor 43 for generating a reference position detection signal of the engine crankshaft, and an engine speed signal, for example, 30.
It has a rotation angle sensor 44 which is generated every ° C A. The rotation angle sensor 44 constitutes the rotation speed detection means 12.
Further, the output signal of the EFI computer 21 is input to the fuel injection valve 37 and the igniter 41, while the necessary data is also transferred to the ECT computer 45.

The ECT computer 45 is a transmission control computer and is composed of a microcomputer. For example, a vehicle speed signal from a vehicle speed sensor 46 which detects the vehicle speed by rotation of an output shaft, and a shift position (gear stage) of an automatic transmission 47.
A gear stage detection signal from the neutral start switch 48 for detecting the position of the gear position is input through the EFI computer 21 to calculate a shift line, and the automatic transmission 47 sets a gear stage setting control (shift control) based on the calculated shift line. Do. The automatic transmission 47 is a device for automatically performing a clutch operation for starting and a gear changing operation for obtaining a necessary driving force, and has a fluid torque converter. Further, 49 is an air conditioner switch, which is an air conditioner (not shown)
Detect the operating state of.

In the above system configuration, the EFI computer 21 realizes the above-mentioned first calculating means 13, second calculating means 14, correction amount calculating means 15 and ignition timing calculating means 16 by software processing. As is well known, the EFI computer 21 has a hardware configuration as shown in FIG. 2, those parts which are the same as those corresponding parts in FIG. 2 are designated by the same reference numerals, and a description thereof will be omitted. In FIG. 3, the EFI computer 21 is a central processing unit (CPU).
50, read only memory (ROM) 51 storing a processing program, random access memory (RAM) 52 used as a work area, backup RAM 53 for retaining data even after engine stop, input interface circuit 54, multiplexer With A / D converter 5
6 and an input / output interface circuit 55, etc., which are connected to each other via a bus 57.

The A / D converter 56 is an air flow meter 32.
The intake air amount detection signal from the throttle position sensor 34, the detection signal from the water temperature sensor 40, the water temperature detection signal from the water temperature sensor 40, and the oxygen concentration detection signal from the O ₂ sensor 38 are sequentially switched through the input interface circuit 54 and taken in.
It is converted from analog to digital and sent to the bus 57 sequentially.

The input / output interface circuit 55 is a detection signal from the throttle position sensor 34 and a rotation speed signal from the rotation angle sensor 44 according to the engine rotation speed (NE), a vehicle speed detection signal from the vehicle speed sensor 46, and a neutral start switch 48. , The detection signals from the air conditioner switch 49 are respectively input, and are input to the C via the bus 57.
Input to PU50.

Further, the CPU 50 executes various arithmetic processing based on each data input from the above-mentioned input / output interface circuit 55 and the A / D converter 56 through the bus 57, and outputs the obtained data to the bus 57 and the input. Through the output interface circuit 55, the ISCV 36, the fuel injection valve 37,
The output is appropriately selected and output to the igniter 41 and the ECT computer 45, the opening of the ISCV 36 is controlled to control the idle speed to the target speed, and the fuel injection time by the fuel injection valve 37, that is, the fuel injection amount per unit time is set. The ignition timing is controlled by the igniter 41, and necessary data is sent to the ECT computer 45. The ECT computer 45 has the same hardware configuration as the EFI computer 21.

Next, an embodiment of the idle ignition timing correction routine of the essential part of the present invention will be described with reference to FIGS. FIG. 4 is a flow chart showing an embodiment of the idle ignition timing correction routine, and the EFI computer 21 realizes the second calculating means 14 and the correction amount calculating means 15. In FIG. 4, the CPU in the EFI computer 21
Reference numeral 50 determines whether or not the throttle opening detection signal from the throttle position sensor 34 indicates that the throttle opening is fully closed (step 101). If the throttle opening is not fully closed, this routine is exited and the throttle opening is opened. Is fully closed, it is determined that the vehicle is in the idle state, and the next step 102
It proceeds to and determines whether or not a predetermined time has elapsed after starting.

Since the engine speed fluctuates greatly and an accurate ignition timing cannot be calculated until a predetermined time elapses after starting,
Exit this routine. On the other hand, after a lapse of a predetermined time after the start, the routine proceeds to the next step 103, where the average value (weighted average value) NES of the engine speed NE calculated based on the detection signal from the rotation angle sensor 44 up to the last start of this routine
A difference (deviation) ΔN between M and the engine speed NE at the time of starting this routine this time is calculated. The above-mentioned smoothed value NESM is, for example, a 1/32 smoothed value, and therefore the difference ΔN in the engine speed is expressed by the following equation.

[0026]

[Equation 1]

In the above equation, NESM _i-1 is the smoothed value up to the previous time. Here, when the idle state enters a stable state after a certain period of time or longer, the above-mentioned smoothed value NESM
Becomes the target idle speed by the idle speed control.

After calculating the difference ΔN, the CPU 50 determines whether or not the shift position of the automatic transmission 47 is in the N range based on the detection signal of the neutral start switch 48 (step 104). ROM51 for N range
The map shown in FIG. 5 (A) stored in advance is searched based on the difference ΔN to calculate the advance correction amount ΔS (step 105).

As can be seen from FIG. 5A, the map of the difference ΔN and the advance correction amount ΔS in the N range described above passes through the point of ΔS = 0 when ΔN = 0 within the predetermined range. A characteristic is shown in which ΔS linearly changes in proportion to ΔN, and the characteristic is set to be point-symmetrical about the point where ΔN = 0 and ΔS = 0. Therefore, in the case of the N range, when the current engine speed NE becomes lower than the previous smoothed value (which is the normal idle target speed), ΔN becomes a positive value, so that the advance correction amount ΔS becomes positive. If the current engine speed NE rises above the previous smoothed value (normally the idle target speed), ΔN becomes a negative value, and thus the advance correction amount ΔS is a negative value. Becomes If the absolute value is the same regardless of whether ΔN is positive or negative, the absolute values of the advance angle correction amounts ΔS are also equal.

On the other hand, if it is determined in step 104 that the range is not the N range, that is, the D range, the map as shown in FIG. 5B stored in the ROM 51 in advance is searched based on the difference ΔN, and the progress is advanced. The angle correction amount ΔS is calculated (step 106).

Difference ΔN and advance angle correction amount Δ in the D range
The two-dimensional map shown in FIG. 5B with S is ΔN = 0, Δ
It is represented by a polygonal line characteristic that passes through the point of S = 0. When ΔN is positive within a predetermined range, ΔS increases in proportion to ΔN,
When N is negative, ΔS decreases in proportion to the decrease of ΔN, but the inclination when ΔN is positive is set to a sharp asymmetric characteristic compared to the inclination when ΔN is negative. .. Therefore, even if the absolute value is the same when the difference ΔN is a positive value and a negative value, the advance correction amount ΔS when ΔN is positive.
The absolute value of is larger than the absolute value of the advance correction amount ΔS when ΔN is negative, and the advance correction amount is larger than the retard correction amount.

As a result, as shown in FIG.
Close to the torque peak of characteristic curve II (same as II in Fig. 9)
The basic ignition timing set point b is located on the non-linear curve.
In the case of the D range which is
As a result, the engine speed NE decreases and ΔN becomes a certain value +
Advance angle correction amount + n when n₁Ignition timing t _F
Torque increase amount TR_FAnd ΔN is the absolute value above
Same polarity but opposite polarity-Advance correction amount when n-
S₂Ignition timing t_BTorque reduction amount TR_BWhen
Can have the same absolute value as each other.

After the calculation of the advance angle correction amount ΔS in step 105 or 106 in FIG. 4, this ΔS is, for example, the RAM 52 in FIG.
(Step 107), the routine ends. Next, an embodiment of the ignition advance value calculation routine of another main part of the present invention will be described with reference to the flowchart of FIG. This ignition advance value calculation routine is a routine for realizing the first calculation means 13 and the ignition timing calculation means 16,
For example, when the engine is started at every predetermined crank angle, first, the output of the intake air amount based on the detection signal of the air flow meter 32 is C
After being read by the PU 50 (step 201), the output of the engine speed NE is read by the CPU 50 (step 202). Then, the basic ignition timing SBASE1 is calculated based on the map when the idle contact is off (IDL off) (step 203).

Next, it is determined from the output detection signal of the throttle position sensor 34 whether or not the idle contact is on (step 204). When it is determined that the idle contact is on, the air conditioner switch 49 and the neutral start switch 48 are turned on / off. Off is determined (step 2)
05). Next, the map when the idle contact is turned on is shown with the intake air amount, the engine speed, and the neutral start switch 48.
The basic ignition timing SBASEIDL corresponding to the engine state at that time is calculated by referring to the ON / OFF state of the engine and the ON / OFF state of the air conditioner switch 49 (step 20).
6).

Next, the basic ignition timing S calculated as described above.
The basic ignition timing SBASEIDL at idle is corrected by adding the advance angle correction amount ΔS calculated by the idle ignition timing correction routine shown in FIG. 4 to BASEIDL (step 207). Next, the basic ignition timing S during off idle
BASE1 and basic ignition timing at idle SBASEID
L is compared with the size (step 208), and SBASE1 ≦
If SBASEIDL, the upper limit guard processing is performed to set the value of SBASEIDL to the basic ignition timing SBASE1 at the time of off-id calculated in step 203 (step 209), and the routine proceeds to step 210.

This is because the basic ignition timing SBASE1 is MB
Since it is set near T, SBASE1 ≦ SBASEI
Basic ignition timing at off-idle SBASEI like DL
If DL is set to a value on the more advanced side than SBASE1, the torque decreases, so this upper limit guard processing is performed to prevent the torque from decreasing. On the other hand, step 2
If it is determined in S08 that SBASE1> SBASEIDL, the process proceeds to step 210 without performing the upper limit guard process of step 209. Also, step 204
If it is determined that the idle contact is off in step 20, step 20
The processing of 5 to 209 is jumped to directly proceed to step 210.

In step 210, the basic ignition timing SBASE1 is set to the advance value SBASE when the idle contact is off,
When the idle contact is on, the basic ignition timing SBASEI
The DL is stored in the RAM 52 as the advance value SBASE.
After that, the ignition advance value θ is calculated and output based on the equation θ = SBASE + θα (step 211). Here, in the above equation, θα is an engine cooling water temperature, various ignition timing correction terms at the time of gear shifting, and is a value calculated by another known routine.

The CPU 50 supplies an ignition instruction signal to the igniter 41 before the top dead center (BTDC) based on the ignition advance value θ calculated in this way, and when the ignition advance value θ is calculated, the ignition coil The primary current is cut off to ignite the spark plug.

As a result, according to the present embodiment, the engine speed NE is reduced (ΔN> 0) and the engine speed is increased by advancing as shown in FIG. 6 during idling when the D range is selected. And when NE rises (ΔN <0)
When trying to reduce the engine speed due to retardation,
When the same torque fluctuation amount is required, the same torque fluctuation amount can be obtained. Therefore, according to this embodiment,
When the ignition timing is not controlled when the D range is selected, FIG.
When the engine speed at idle varies as shown by solid line III, the swell of the engine speed can be suppressed uniformly as shown by solid line V in the figure, and the fluctuation of engine speed by conventional ignition timing control can be suppressed. Even compared with IV, the rotation speed can be suppressed more sufficiently, and the idle rotation speed can be controlled to the target rotation speed.

The present invention is not limited to the above embodiment, and the advance correction amount can be calculated by the routine shown in FIG. That is, when the air conditioner is on and the air conditioner is on, the basic ignition timing is advanced by a predetermined angle compared to the basic ignition time when the air conditioner is off and the air conditioner is off. Similar to the above, the basic ignition timing is set in the non-linear portion close to the torque peak of the ignition timing-torque characteristic.

Therefore, in another embodiment of the present invention, an idle ignition timing correction routine is executed as shown in FIG. In the figure, the same steps as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 8, after calculating the difference ΔN, it is determined whether the air conditioner switch 49 is off (step 301). When the air conditioner switch 49 is off, the routine proceeds to step 302, where the advance angle correction amount ΔS is calculated based on the map when the air conditioner switch 49 is off. The map when the air conditioner switch 49 is off is similar to the map shown in FIG. 5 (A), and shows a point-symmetrical characteristic around the points ΔN = 0 and ΔS = 0.

On the other hand, when it is determined in step 301 that the air conditioner switch 49 is on, the routine proceeds to step 303, where the advance angle correction amount ΔS is calculated based on the map when the air conditioner switch 49 is on. This air conditioner switch 4
The map when 9 is on is similar to the map shown in FIG. 5B, and shows asymmetric characteristics with respect to the points ΔN = 0 and ΔS = 0. As a result, it is possible to prevent uneven correction of the engine speed undulation during idling, which tends to occur when the air conditioner switch 49 is turned on.

[0043]

As described above, according to the present invention, when the basic ignition timing is set in the non-linear portion close to the torque peak of the ignition timing-torque characteristic, the ignition timing is advanced from the basic ignition timing. The absolute values of the torque increase amount based on the correction amount for advancing the predetermined value to the angle side and the torque decrease amount based on the correction amount for delaying the same ignition side to the retard side from the basic ignition timing can be made substantially the same. As a result, the waviness of the engine speed during idling can be suppressed more than before, the idle speed can be controlled more stably to the target speed, and the drivability can be improved. It has the features of

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a system configuration diagram of an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a hardware configuration of the EFI computer in FIG.

FIG. 4 is a flow chart showing an embodiment of an idle ignition timing correction routine of the essential part of the present invention.

5 is a diagram showing a map used in the routine of FIG. 4. FIG.

FIG. 6 is a diagram illustrating a relationship between ignition timing and torque during idling when the D range is selected according to an embodiment of the present invention.

FIG. 7 is a flow chart showing an embodiment of an idle ignition advance value calculation correction routine of another main part of the present invention.

FIG. 8 is a flowchart showing another embodiment of the idle ignition timing correction routine of the essential part of the present invention.

FIG. 9 is a diagram showing a relationship between a conventional ignition timing and torque during idle when the D range is selected and when the N range is selected.

FIG. 10 is a view showing a state in which the swell of the rotation speed is suppressed between the conventional device and the present embodiment in comparison.

[Explanation of symbols]

 10 Internal Combustion Engine 11 Detecting Means 12 Rotation Speed Detecting Means 13 First Calculating Means 14 Second Calculating Means 15 Correction Amount Calculating Means 16 Ignition Timing Calculating Means 21 EFI Computer 41 Igniter 47 Automatic Transmission 48 Neutral Start Switch 49 Air Conditioner Switch

Claims (1)

[Claims] 1. A detecting means for detecting an idle state of an internal combustion engine, a rotational speed detecting means for detecting an engine speed of the internal combustion engine, and a first ignition timing calculating means for calculating a basic ignition timing in accordance with an engine state at the time of idling. A calculation means; a second calculation means for calculating a deviation between the engine speed detected by the rotation speed detection means and a target rotation speed during idling; and the basic ignition timing calculated by the first calculation means. When the engine is operating in a non-linear portion near the torque peak of the ignition timing-torque characteristic, the ignition timing is advanced or retarded in accordance with the deviation of the engine speed calculated by the second calculating means. Correction amount calculating means for calculating an asymmetric correction amount between the side and the ignition timing for correcting the basic ignition timing based on the correction amount calculated by the correction amount calculating means and outputting a value for determining the ignition timing. Operator And the correction amount calculating means sets the correction amount to a value on the retard side when the engine speed rises above the target speed, and when the engine speed drops below the target speed. The correction amount is set to a value on the advance side, and when the deviations of the engine speed are the same, the absolute value of the correction amount on the advance side has an asymmetric characteristic larger than the absolute value of the correction amount on the retard side. An ignition timing control device for idling, wherein the correction amount is calculated based on the above.