JPS6187976A - Ignition timing control of engine - Google Patents

Abstract

PURPOSE:To improve the control accuracy by calculating the average value of actual rotation of engine at the time point when the actual idle rotation has approached to target rotation than controlling the ignition timing on the basis of the difference between said average value and the actual engine rotation. CONSTITUTION:When operating an internal-combustion engine 20, an electronic control circuit 44 will first calculate the actual engine rotation NE on the basis of the output from crank angle sensor 48 then calculate Q/NE on the basis of NE and the fuel flow flow Q to be operated with correspondence to the operating condition. Under idling where an idle switch 10 is turned off, the average ignition timing lead angle is set to a referential level. Upon detection that NE has reached within the target level range, control is started while employing NE at that time as the initial target level thus to calculate the average level of NE or NEn. Then the ignition timing lead angle is controlled on the basis on NEn and NE thus to control the engine rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of application on the optical path] This book B relates to a first-time ignition timing method for stabilizing the engine speed during idling (hereinafter referred to as idling speed).

[Conventional technology]

In general, when an electrical load such as a lighting system or wiper is applied when the engine is idling, or when there is a change in fuel that is not being supplied when the engine is idling, the engine speed may become regular or irregular. change to

゛If the engine speed when idling is low, such fluctuations in engine speed will cause the engine speed to drop, and sometimes engine stalling will occur. There was a problem in improving fuel efficiency as there was a high return setting. □ To solve this problem, set the target idle speed NF in advance.
There is a known method in which the ignition time is determined based on the deviation value between the actual idle speed nNE and the target idle speed NF.
Publication No. 470].

This control method utilizes the characteristic that under no-load engine conditions, advancing the ignition timing at the same throttle opening and air-fuel ratio will increase the engine speed, and retarding the ignition timing will cause the engine speed to decrease. The configuration is to calculate the actual idle rotation speed, compare this actual idle rotation speed with a preset target idle rotation speed, and when the actual idle rotation speed is greater than the target idle rotation speed, the engine idling speed is determined. Total reduction in ignition timing advance amount ζ
In addition, when the actual idle speed is smaller than the target idle speed, the amount of advance of the ignition timing is increased≧. As a result, the ignition advance angle is controlled so that the ignition advance angle corresponds to the target idle rotation speed, and the idle rotation speed is controlled to reach the target rotation speed.

However, with this control method, j, b, Fig. 13 (a
) as shown by the solid line in Fig. 13 (bl
As shown in , since the idle speed is controlled by controlling the ignition timing, when the amount of air during idling is large, the KFi and the actual idle speed become higher than the target idle speed, and the ignition timing is delayed. , fuel efficiency worsens. - When the amount of air during idling is small, the actual idle speed NE becomes lower than the target idle speed NF, as shown in Figure 13 (C), and the ignition timing advances, resulting in a low idling that originally lacks stability. The rotational speed is further affected by the control that causes the idling to become unstable.

When the angle becomes overadvanced, a misfire occurs as shown in MF shown in FIG. 13(e), and the rotational speed fluctuates greatly. Therefore, even if the ignition timing is controlled, there is a possibility that the effect of stabilizing the idle speed will be almost eliminated.

Recently, in order to stabilize the engine rotation speed during idling, a detour is provided to bypass the throttle valve, and an idle speed control (hereinafter referred to as SC) is installed on this detour. , when the throttle valve is fully open and both vehicles are stopped or at low speed (for example,
By controlling the opening degree of the ISC valve during idling (0 to 2 km/h), the air flowing to the detour is controlled to set the engine rotation target rotation speed (NF: 8: NE (for example, 670 to 730 rpm). (within range).

When this ESC valve control and the conventional ignition timing control described above are used together, the deviation between the actual idle speed NE and the target idle speed NF can be reduced by a relatively small amount, as shown in Figure 2g13 (cl, (d)). As mentioned earlier, the fuel consumption is extremely poor (however, the idle speed is very stable), and the idle speed is extremely unstable (however, this affects the fuel efficiency). This can be prevented from occurring.

[Problem to be solved by the invention 3 As mentioned above, ■ When SC control and conventional ignition timing control are used in conjunction with t1-7, it is possible to completely suppress fluctuations in fuel consumption and idle speed. , Tolerance - I) Pronation remains a problem.

Therefore, the present invention provides, when the engine is idling,
To provide engine speed control capable of constantly stabilizing idle speed and preventing significant deterioration of fuel efficiency.

(Means for Solving the Speed Ratio Point) In order to solve the above problem, the present invention provides a method for solving the problem from the point when the actual engine speed at idling approaches the target engine speed at the time of idling of the engine. Control is started using the actual engine speed as an initial target value, and calculation of the average value of the actual engine speed is started, the average value up to the present is determined, and this average value is compared with the actual engine speed. The feature is that the ignition timing is controlled based on the obtained deviation value.

[Effect]

According to the present invention having the configuration as described above, the point in time when the actual engine speed approaches the target engine speed.

In other words, the ignition timing control is fully started from the moment the actual engine speed reaches the stable region, so stability can be ensured, and when controlling the ignition timing, the target is always the average value of the actual engine speed. Since it is performed as a value, the control precision [k
Ditto Shiroko.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings. Note that the embodiments described below do not apply to the present invention. An example of application to a 1ζ engine equipped with an rISC valve control device will be described, but it can also be applied to ignition timing advance control without NSC control due to the correlation between the target idle speed and the actual idle speed. be.

First, ISO valve control will be explained, and then advance angle control according to the present invention will be explained.

□Engine□ Fig. 2 shows an example of an internal combustion engine (engine) equipped with a KISC valve control device. This engine has an air cleaner (
(not shown) is provided with an air flow meter 2 that outputs an intake air amount of 4'+. Air flow meter 2F
i. A convention plate rotatably provided in the damping chamber, a measuring plate connected to the compensation plate, and a potentiometer 4 for detecting the opening degree of the measuring plate.

Therefore, the intake air t#'i can be determined from the intake air infusion signal outputted from the potentiometer 4 as a voltage value.

Further, an intake temperature sensor 6 is provided near the air flow meter 2 to detect the intake air temperature and output an intake temperature signal.

A throttle valve 8 is installed on the downstream side of the air flow meter 2, and an idle switch 10 that is turned on when the throttle valve is fully closed (idle position) is installed on the throttle valve 8. A surge tank is installed on the downstream side of the throttle valve 8. 12
is not yet established. Further, a bypass path 14 is provided so as to bypass the throttle valve 81 and communicate the upstream side of the throttle valve with the surge tank 12 on the downstream side of the throttle valve.

An ISC valve 16A whose opening degree is controlled by a pulse motor 16 equipped with a four-pole stator is attached to this detour 14. The surge tank 12 is communicated with the combustion chamber of the engine 20 via an intake manifold 18 and an intake boat 22. A fuel injection valve 24 is attached to each cylinder so as to protrude into the intake manifold 18.

The combustion chamber of the engine 20 is connected via an exhaust boat 26 and an exhaust manifold 28 to a catalytic converter (not shown) filled with a three-way catalyst. An oxygen sensor 30 is attached to the exhaust manifold 28 for detecting the residual oxygen concentration in the exhaust gas and outputting an air-fuel ratio signal. An engine coolant temperature sensor 34 is attached to the engine block 32Kij and the block 32t-y+a so as to protrude into the water jacket.The coolant temperature sensor 34 detects the engine coolant temperature and outputs a water temperature signal.

A spark plug 38 is attached to each cylinder so as to penetrate the cylinder head 36 of the engine 20 and protrude into the combustion chamber. It is connected to the configured electronic control circuit 44. A cylinder discrimination sensor 46 and a crank angle sensor 48 are installed inside the distributor 40, each of which includes a signal rotor fixed to the distributor shaft and a pickup fixed to the distributor housing. The cylinder discrimination sensor 46 of the 6-cylinder engine outputs a full cylinder discrimination signal every 720'CA, and the crank angle sensor 4Bit outputs a cylinder discrimination signal every 720'CA, for example.
Outputs an engine rotation speed signal every A. Note that 56 is a vehicle speed sensor that is composed of a magnet fixed to the speedometer cable, a reed switch, and a hunting sensing element, and outputs a vehicle speed signal in accordance with the rotation of the speedometer cable.

1. Electronic control circuit 1. FIG. 3 shows the configuration of the electronic control circuit 44 for controlling the above engine. The electronic control circuit 44 includes a central processing unit (CPU) 6o, a read-only memory (ROM) 6
2. Random access memory (RAM) 64, backup RAM (Bu-RAM) 66, input/output capotro 8
, an analog-to-digital converter IADc170, and paths such as a data bus and a control bus that connect these. A vehicle speed signal, a cylinder discrimination signal, an engine rotation speed signal, a throttle fully closed signal from an idle switch 10, and an air-fuel ratio signal are input to the input/output capotro 8. In addition, the input/output capotro 8 outputs to the drive circuit an ISO valve control signal for controlling the opening degree of the ISC valve, a fuel injection signal for opening and closing the fuel injection valve, and an ignition signal for turning on and off the igniter. , rd"h circuit operates the ISC valve, fuel injection valve,
Control each igniter. In addition, an intake air amount signal, an intake air temperature signal, and a hot water signal are input to the ADC 70.
, IV the Konemono signal according to the instructions of the ADCldCPU.
I love RI & digital signals. It Oλ162 contains engine cooling water temperature, intake temperature, target rotational speed determined according to the drawing condition, pulse motor control ail t, and manual SC valve opening. The 1ζth control program and the like are stored in advance.

1. Control of the ISC valve during idling - Next, a method for controlling the ISC valve during idling will be described. In addition, in the following, the explanation will be simplified.
Here, the explanation will be made using optimal values, but the present invention is not limited to these values. Is this example a feedback system during idling? When the 1111 condition is met, the engine rotational speed N is 67 Orpm ~ 7
It is controlled so that the value is within 30 rpm.

■ Main routine for calculating the final target number of steps STP Figure 4 shows the main routine for calculating the final target number of steps STP'r to control the number of steps of the pulse motor that drives the ISC valve and adjusts its opening. shows. First, in <Step 100> it is determined whether the engine cooling water temperature is 70°C or higher, in <Step 101> it is determined whether the vehicle speed V is less than 2 km/h, and the throttle valve is fully closed in Step 102>. By determining whether the feedback control conditions are satisfied or not, it is determined whether the feedback control conditions are satisfied or not.

If any one of the judgments in steps 100 to 102 is negative (if the feedback condition is not satisfied), steps 120 to 12 in FIG.
The count value Ctime, which is incremented by 1 at the interrupt milling every 4 m5ec, is set to O in <Step 103>, and the count value Ctime shown in <Step 104
After setting the value of the learning step number STG to the target step number ST in 〈Step〉〉, the start flag (hereinafter referred to as the advance control flag) of the ignition timing advance position allocation (, lTI I), which will be described later, is set in 〈Step〉〉. ) Fs is reset to O', and then in step 116, a start flag (hereinafter referred to as
The average (direct γJ, called output flag) is reset by setting it to '0#', and then proceeds to <Step 114>.

- 10,000, <Step 100 to Step 102> 4: When all of the 1 judgments are affirmative (when the feedback control conditions are established), the engine rotation and vehicle seat N are determined in <Step 105> and <Step 106>. is 67 t)
k IAI is determined whether the value is within the range of rpm to 730 rpm. Engine speed vNII; 7
', when 30 rprn or more, <Step 107>
If the count value Ctime is 500 or more, that is, 2 s
It is judged whether the ec nature has exceeded 1 or not, and if 2 SeC has passed, the target step number ST is set to 1 in <Step 108>.
At the same time, the count value Ct is decreased in <Step 109>.
ime (r O) and proceed to <Step 114>.

When the engine speed N is 670 rpm or less,
In step 110, it is determined whether or not 2 seconds have elapsed, and when 2 seconds have elapsed and 7, the target step number is increased by 5 Tkl in step 111, and the count value Ctime f is set as Q in step 112.Step 114
Proceed to.

Furthermore, if the engine rotation speed N is within the range of 670 to 730 rpm, the engine rotation speed N is being controlled to the target rotation speed.
After setting the advance angle control flag Fsi'l" in step 7>, the target step number ST' at this time is set as the learning step E"l STG in the Bu-RAM 66 in step 113>.
The process then proceeds to <Step 114>.

In <Step 114>, the target number of steps STi is set as the final target number of steps STP.

Q3) ISC valve opening control routine Next, refer to Figure 6.
Executed by an interrupt near m5ec. As shown in Fig. 7, the step motor is equipped with a four-pole stator of KN to N4. When it rotates counterclockwise once, the 4-step molecular SC valve opens.

First, <step 130> l/(, from the final target step r STP to the current step number C of the step motor
Reduce PM by O, and find the difference CRTJN.

In <Step 131>, it is determined whether or not the difference CR,UN is not 0. If the difference CRUN is 0, the final target step number STP and the current step number ("PM") match, so <Step 153 > resets the flag F1sck, and then outputs n in step 154>.

The stators N, -N are controlled in accordance with the values of the outputs n, -n4 in <Step 155>, with all values of -n set to O. As a result, all of the four-pole stators are energized or de-energized, and the rotor is not rotated.

If the difference CRU N is not 0, in step 132, the current step number CPM' is divided by the number of stator poles 4, IF,
L*The remainder is set as a, and it is determined which direction of the stator the rotor is currently facing. Note that when the remainder a is 0, that is, when the rotor is facing the direction of the stator N, the remainder a (54) is set in <Step 133> and Step 134>.

In the next step 135, it is determined whether or not the flag F"tsc is set, and when the flag Fl!Ic is reset and the rotor is stopped without being excited, ) is set to the outputs n and il corresponding to the stator in the direction in which the rotor is currently facing in <Step 136>, and is set to 7 lag F1sc1 in <Step 137>, and the process proceeds to Step 155>. , when the rotor is once stopped and stabilized in the direction in which it is currently facing and the flag FI8C is set (after the rotor is stabilized in the direction in which it is currently facing) Fi,<Step 13
8> determine whether the difference CRUN is negative or not. difference CRtJ
(When N is positive and no force is generated unless the tIsc valve is opened), in step 139〉, the value obtained by adding 1 to the remainder a is set to Find the first child of . Note that since the stator has four poles, when the value of b exceeds 4, <Step 14
0>In step 141>, the value of b is set to 1.

In step 142>, the output n of the stator corresponding to b is
, is 1 or not. If n>=0, in step 143>, set nb=l and proceed to <step 155>. As a result, the rotor has a stator corresponding to b and b-1
and the corresponding stator, and rotated by 1/2 step. - When n, = 1, step 14
4〉, stator output “mt” corresponding to b-1 (=a)
In step 145, set the current step number CPM.
il is incremented, and after 1ζ the process proceeds to step 155>. As a result, the rotor is rotated an additional 1/2 step.

The case where the step motor is controlled in the direction of opening the ISC valve as described above will be described in more detail with reference to Section 7A. First, it is assumed that the rotor faces the stator N with all of the four-pole stators demagnetized. When stator N, is excited, the rotor does not rotate, but stators N,,N.

When energized, the rotor points in the direction between stator N1 and stator N, and when stator N is fully demagnetized and the identifier Ntt- is energized, the rotor points in the direction of stator N. Furthermore, 1 stator N, 11C excitation 1. When the stator Ns is energized in this state, the rotor becomes stator N and stator N.

Demagnetize the stator N, facing the direction between the
When m' is excited, the rotor points toward the stators N and a. This causes the rotor to rotate two steps in the direction that opens the ISC valve.

10,000, when the difference CRUN is negative (when the ISC valve must be closed), in <Step 146>, subtract 1 from the remainder a and set the value 1:cb to the stator in the direction in which the rotor is currently facing. Find the adjacent stator. Then, in step 147>, it is determined whether the value of b is less than or equal to θ, and if it is less than 0, the value of b is set to 4 in step 148>.
shall be. In <Step 149>, the output n of the stator corresponding to Hlb is determined.

is 1 or not' (44J is cut, n6 ” O is passed. In step 150, set n, = 1 and proceed to <step 155>. If n, = 1, in <step 151> b+1f=a
) is set to O, and the current number of steps CP M i
After decrementing by 1, proceed to <Step 155>. As a result, the rotor is rotated in a direction that closes the ISC valve.

Here, the number of steps 5 TUPVi is decreased by 1 every 5 seconds, and ISC is
The valve is operated once every 8 m5ec according to the routine shown in Figure 6.
Since the valve is opened and closed by steps, when opening the mechanical SC valve by 6 steps, it is opened and closed by 1 step every Bmsec, that is, 12 steps.
It is opened at a rate of 5 steps/sec, and when the ISC valve is closed, it is closed at a rate of 1 step every 0.5 sec, or 2 steps/sec.

In this way, the ISC valve control controls the opening degree of the ISC valve, which is provided in the bypass path that bypasses the throttle valve and communicates the throttle valve downstream side with the throttle valve downstream side, during idle link. Feedback control is performed so that the engine rotation speed becomes the target rotation speed. When the vehicle speed exceeds a predetermined value, that is, in a high speed range where the engine is likely to stop when the clutch is disengaged, feedback control is stopped and the ISC valve is opened for a predetermined period of time from the opening degree during feedback control, and the engine flows to the detour. Engine stop is prevented by increasing the air amount Ffl.

When the vehicle speed becomes smaller than the predetermined value and less than the predetermined value,
i.e. clutch? In a low stopping speed range where the engine rotational speed does not decrease much even when the clutch is disengaged, the ISC valve is closed at an opening of more than half of the predetermined opening while leaving a necessary constant opening to reduce the engine rotational speed when the clutch is disengaged. This not only improves fuel efficiency, but also improves the effectiveness of engine braking.

Then, when the vehicle stops, the constant opening ESC
Close the valve and start feedback control.

- Ignition timing control during idling - First, an outline of ignition timing control during idling according to the present invention will be explained. In this control method, as shown in FIG. 70, which is between 670 and 730 rpm.
At this point (hereinafter referred to as the start point), ignition timing control, which will be described later, is started. Control up to this starting point Ts is performed by ISC valve control, and the control is stopped when the number of revolutions reaches an eyesore range. When the starting point Ts is reached, the actual idle speed NEi at 7
Let the initial target value (hereinafter referred to as initial value) NE be, and compare this initial value NE with the actual idle speed NE [2
Control of the ignition timing is started so that the deviation of 7 is reduced to 0. - As soon as the starting point Ts K is reached, calculation of the average value NEn of the actual idle speed NE up to the current control point is started, and from then on, the average value NEn at each point becomes the target value, and this average value Ignition timing control is performed so that the comparison deviation between NEn and the actual idle speed NE is zero. To control the ignition timing by comparison, as shown in Fig. 8, for example, control 1tl'W' of ±10 Orpm of the target rotation speed is applied, and for deviations exceeding ±10,100 rpm, control the ignition timing by ±10 Orpm with respect to the standard advance angle θB3B. 'The first method is to keep CA (crank angle) constant, and as shown in Figure 9,
By adding an additional 20 rpm to the control width of m, ±12
If Orpml is exceeded, a second method can be considered in which the ignition timing control is completely stopped. Hereinafter, the first method and the second method will be explained separately.

(a) Initial set and various calculations In FIG. 10, a so-called initial set is performed at the beginning of the process (step 200). Next, the fuel flow rate Q and engine speed NE are taken in, Q/N
E is calculated (step 201). Next, the number of steps of the step motor to determine the problem of the ISC valve is 5TP.
O operation is performed (step 202). This step number STP calculation uses the ``main routine for calculating the prisoner's final target step number'' previously shown in FIG. Next, the fuel injection time T is calculated (step 203). This fuel injection time 'r is calculated, for example, where k is calculated using a correction coefficient.

(b) Ignition timing calculation routine +204) After executing steps 200 to 203> above, the ignition timing calculation routine 204 is executed.

This ignition timing calculation routine 204 is as follows. In <Step 205>, the idle switch is set to 5.
It is difficult to determine whether it is OFF' or not, idle switch =
If it is OFF, the processing flow in normal operation state is Step 2.
The process proceeds to step 06>, and the process flow proceeds to step 207 in which the idle switch is turned OFF, so to speak, in an idling state.

In the normal operating state (idle switch = OFF), in <Step 206>, the reference angle θBIB is calculated from the data of Q/NE and NE. This calculation formula is stored in advance in the RAM.
It is stored in 64 maps. Next, <Step 2
08〉, ISCπ11 Opening advance angle θXsc t= 0
Set to °. Then, in <Step 209>, the execution ignition advance angle θ1o is determined, and the process returns to <Step 201>, where the execution ignition advance angle 'I
Q” control.

- 10,000, idle operation status (idle switch N0FF
), and in <Step 207>, the average ignition timing advance angle θ8 during idling is determined. is the reference ignition timing advance angle θ88
Set it to B. The average ignition timing BTDC is determined depending on the type and capacity of the engine, is a value known empirically and experimentally, and is stored in the map of the RAM 64. Here, 158 BTDC is used as an example.

Next, in step 211>, the advance angle control flag F
Check whether s is set to 11' and set Fs=
If it is O, the process is moved to the normal operation flow described above, and the FS
If = 1, it means that the actual engine speed NB has reached the target value range, which corresponds to the starting point TsK in Fig. 1, so
Proceeding to <Step 212>, a routine 212 for calculating the average value NEn of the actual idle speed NE is executed. This NEn
Details of the calculation routine 212 will be described later with reference to FIGS. 11 and 12. When the processing of the NEn calculation routine 212 is completed, <Step 213>
The advance angle θtSC is calculated in the C calculation routine 213, and the calculated value is used for calculation in <Step 209>. Thereafter, the same pressure is applied and the process returns to <step 201>K to repeat the process.

(c)NEnt? , out Lu Chia (2141 here,
NEnB output routine 214 will be explained. Referring to FIG. 11, in step 3oO> it is determined whether the average value calculation flag FNE is set to 11#,
If F, -=O [Proceed to Fi <Step 301>, F
If W74=", step 30 of the average value calculation flow
Proceed to 2>.

If F'fi=o, it is determined in step 301 whether the actual idle rotation speed NE is 73 Orpm or less. NE>73Orpm means that there is no #:t in the idle link state. Therefore, in step 303>, the ISC advance angle θ□8cwoOc' is set, and this N
E. Calculation routine 214I/'i ends.

If NE≦73 Orpm, it means that the rotation speed is approaching the target rotation speed due to feedback control,
In step 304>, the actual idle rotation speed NE' at this time is initialized as the actual idle rotation speed average value N B r . The initial values NE and Iri become the target values at this point. Next, in <Step 305>, average value calculation 7
Set the lag F 'e'l'' and set the ISC control advance angle θ□
Step 8c of the calculation routine 213 proceeds to <Step 306>K.

(d) ISC control advance angle θ□8c calculation routine (213
) In step 306>, it is determined whether the deviation between the initial value NE and the current actual idle rotation speed NE is 10 Orpm or more based on the initial value set in step 304>. And the low side deviation INE.

- In the case of NBl≧10 Orpm, the current actual idle speed NB is 100 rpm lower than the initial value NE.
Therefore, in step 307, the ISC advance angle θISC is advanced by 10 degrees to increase the rotation speed.If the low side deviation (NE, -NE) is <10 Orpm, proceed to step 308>. High side deviation (NE-Nl':,
It is determined whether l≧l 00 rpm, that is, the deviation between the actual idle rotation speed NE and the initial value NE exceeds 100 r pln. If the speed is 100 rpm or more, the ISC advance angle θISC is set to 1 by step 3o9>
Delay by 0° to lower the rotation speed. High side 0M difference (NE-
In the case of NE, l < 10 Orpm, interpolation calculation is performed in step 310>, and the output value = iI
The SC advance angle θLJC is set, and the routine 204 ends.

Further, in <Step 3o5>, the average value calculation flag F
When set to =1, it is determined in <Step 302> whether or not the count value Ctime is greater than 25'. If Ctime≧25, proceed to step 3o8〉, and Ctime Since it is incremented by +1 every 4 m5ec, this means that this processing flow is executed every 100 m5ec.If she is pregnant and Cttme≧25, the count value Ctime is set to 0 in the next step 311. Therefore, the counter resumes counting operation again.Next, in <Step 312>, the average value N of the actual idle rotation speed is calculated.
En is required. In calculating this average value NEn, the weighted average value NE is used in <Step 306>, replacing the previously set initial value NE, and from now on, this average value NEni is used as the target value by the θf8c calculation routine 213. Advance angle control will be performed in the same manner as described above.

B. Second method (see FIGS. 9 and 12) The difference between this second method and the first method is that, as shown in FIG. <Step 314> is inserted between <Step 306> and Step 307>.
〉Step 313〉 is inserted between 〉Step 308〉, and 〈Step 315〉 is added. Since the other steps are the same as those in the first method, the same reference numerals are given and the explanation thereof will be omitted.

In <Step 306>, the low side deviation (NEn (also tiN
If E, 1 - NE) ≧ 10 Orpm, the process proceeds to <Step 314> and further calculates the lower side deviation (N En (NE, 1
-NE)≦12 Orpm is determined. If the low side deviation (NEn-NE) is smaller than 12 Orpm, the advance angle is uniformly advanced by +10° and set to θ□8c. As a result, the idle speed NE increases. Low side deviation (N
If En-NE) is larger than 12 Orpm, it exceeds the control range during idling, so in <Step 315> the SC control advance angle is set to θISC”°,
End this control flow (i.e. stop ignition timing control)
do.

In <Step 306>, the low side deviation (NEn-NE+<
In the case of 10 Orpm, proceed to step 313>.
It is determined whether the high side deviation (NE-NEn) is greater than 12 Orpm. High side deviation (NE NEn) is 12
If it is larger than Orpm, the control range at idling is exceeded, so the process proceeds to <Step 315>.
Stop control. -10,000, high side deviation (NE-NEn) is 1
If the rotation speed is smaller than 2 Orpm and greater than 1100 rpm (+100<NE-NEn>120), then in <Step 309>, θ[8Ck- is set to be delayed by −10°, and the control is terminated. Also, <Step 31
If the high side deviation (NE-NEn) is smaller than 10 Orpm in step 5>, interpolation calculation is performed in step 310>, the calculated value is set to 018C, and the control is terminated.

In this way, in the present invention, in order to control the average value NEn' of the actual engine speed NE as the target value, as shown by the broken line in FIG. 13(a), It does not deviate significantly from the standard advance angle θB8°, and even when the ISO valve control device is used together, the 13th
As shown in FIGS. (c) and (d), control with even fewer fluctuations becomes possible. As a result, as shown in FIGS. 13(e) and 13(f), large fluctuations can be suppressed as in the conventional case.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to always maintain a stable idle rotation speed when the engine is idling, and to prevent a significant deterioration in fuel efficiency.

[Brief explanation of the drawing]

Figure 1 is a living room diagram showing the concept of ignition timing control according to the present invention, Figure 2 is a diagram showing the schematic configuration of an engine equipped with an ISC valve control device, and Figure 3 is a block diagram showing the electronic control circuit. , Fig. 4 is a flowchart of the step number calculation routine of the step motor of the #-1 Isc valve, Fig. 5 is a flowchart of the interrupt routine, Fig. 6 is a flowchart showing the opening control routine of the Isc pulp, Fig. 7 is the control of the step motor Flowchart showing aspects, No. 8
The figure is an explanatory diagram showing a first method in an embodiment of the present invention,
FIG. 9 is an explanatory diagram showing the second method, FIG. 10 is a flowchart showing a schematic flow of an embodiment of the present invention, and FIG. 11 is a flowchart showing the ignition timing p and output routine in the first method.
FIG. 12 is a flowchart showing the ignition timing n output routine in the second method, and FIG. 13 is a waveform diagram showing a comparison of the rotational speed fluctuation and ignition timing between the conventional method and the present invention. NE,...Initial value NEn...Average value 204...Ignition timing calculation routine 212/NE, W output routine

Claims (1)

[Claims] From the point in time when the actual engine speed during idling approaches the target engine speed when the engine is idling, control is started using the value of the actual engine speed at this point as the initial target value, and the average of the actual engine speeds is started. The ignition timing of the engine is characterized in that the ignition timing is controlled based on the deviation value obtained by starting the calculation of the value and finding the average value up to the present time, and comparing this average value and the actual engine rotation speed. Control method.