JPH10318111A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the unstableness of an engine due to excess spark advance in an excess fuel condition, in spark-advance-correcting ignition timing at the time of low-temperature engine. SOLUTION: An advance correcting value TADV is set so as to advance with low water temperature in accordance with water temperature Tw usually (S4). In contrast with this, an advance correcting value TADV is fixed to an advance correcting value RADV 1 at the time of water temperature Tw = a given value Tw 1 when water temperature Tw is a given value Tw 1 or less, and an equivalent ratio ϕ is in a rich condition wherein an equivalent ratio ϕ is a given value ϕ1 or more (S3, S4). A spark advance correcting value TADV is added to basic ignition timing MADV to calculate ignition timing ADV (S6).

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 for an internal combustion engine that sets and controls an ignition timing based on an operating state of the engine.

[0002]

2. Description of the Related Art In general, an ignition timing control device for an internal combustion engine employs a system in which the ignition timing is advanced in response to a decrease in combustion speed due to a decrease in gas temperature in a cylinder when the engine temperature is low immediately after starting or the like. ing. That is, as shown in FIG. 11, an advance correction value is set so as to advance the lower the coolant temperature in accordance with the cooling water temperature Tw of the engine, whereby the ignition timing is advanced.

[0003]

However, in such a conventional ignition timing control method at a low water temperature, regardless of the fuel injection amount, more specifically, regardless of the equivalent ratio expressed by fuel mass / air mass. Since the ignition timing is advanced in proportion to the decrease of the water temperature, as shown in FIG. 12, when the equivalent ratio φ is around 1.0, the ignition timing after the water temperature correction (dotted line) Coincides with the required ignition timing (solid line), but in the rich region (excess fuel region) where the equivalent ratio φ is, for example, 1.2 or more, if the water temperature Tw falls below the predetermined value Tw1, the required ignition timing does not advance. (Because the combustion deteriorates too much and the angle cannot be advanced), an error occurs between the ignition timing after water temperature correction and the required ignition timing, and the engine becomes unstable due to excessive advancement, resulting in abnormal noise. There is a problem that occurs.

An object of the present invention is to solve such a conventional problem.

[0005]

Therefore, according to the first aspect of the present invention, as shown in FIG. 1, a water temperature detecting means for detecting a cooling water temperature of an engine, and the water temperature is advanced in accordance with the cooling water temperature. Ratio detection means for detecting an equivalence ratio expressed by fuel mass / air mass in an ignition timing control device for an internal combustion engine, comprising: an ignition timing water temperature correction means for setting an advance correction value to correct an ignition timing. Means for fixing the advance correction value by the ignition timing water temperature correction means to the advance correction value when the cooling water temperature is a predetermined value when the cooling water temperature is equal to or lower than a predetermined value and the equivalent ratio is equal to or higher than the predetermined value. Angle correction value fixing means.

According to a second aspect of the present invention, there is provided basic ignition timing storage means (map) for storing basic ignition timing using the engine speed and load as parameters. The ignition timing for control is calculated by adding or subtracting a lead angle correction value to or from the basic ignition timing retrieved from the storage means.

According to the third aspect of the present invention, as shown in FIG. 2, flame speed calculating means for calculating a flame speed based on a value obtained by multiplying a laminar flame speed basic value by a water temperature correction coefficient, Based on the MBT (optimum ignition timing), the fuel efficiency becomes the best so that the smaller the flame speed is, the more the flame angle is advanced.
The ignition timing water temperature correction means is a water temperature correction coefficient setting means for setting the water temperature correction coefficient as the advance angle correction value to be smaller as the water temperature is lower in accordance with the cooling water temperature. The angle correction value fixing means fixes the water temperature correction coefficient by the water temperature correction coefficient setting means to a water temperature correction coefficient when the cooling water temperature is a predetermined value when the cooling water temperature is equal to or lower than a predetermined value and the equivalent ratio is equal to or higher than a predetermined value. It is a water temperature correction coefficient fixing means.

In the invention according to a fourth aspect, the MBT calculating means adds a predetermined ignition delay time to a value obtained by dividing the total gas weight in the cylinder by the unburned gas density and the flame speed, and adds the predetermined value to the engine speed. Convert the unit to crank angle by the number,
It is characterized by calculating MBT.

[0009]

According to the first aspect of the invention, when the cooling water temperature is equal to or lower than a predetermined value (low temperature) and the equivalent ratio is equal to or higher than a predetermined value (rich), the ignition timing is not advanced to a predetermined value. In addition, since the advance correction value is fixed, an error does not occur between the control ignition timing and the required ignition timing even in a low water temperature and over fuel condition, thereby preventing the engine from becoming unstable and generating abnormal noise. The effect is obtained. In addition, HC, NOx
It also has the effect of suppressing an increase in emissions.

According to the second aspect of the present invention, the present invention can be easily applied to a system using a basic ignition timing map. According to the third aspect of the present invention, in the method of calculating the flame speed and calculating the MBT based on the flame speed, when performing the water temperature correction in the calculation of the flame speed, the water temperature correction in a low water temperature and over fuel condition. By fixing the coefficient, it is possible to prevent instability of the engine and generation of abnormal noise due to overcorrection.

According to the fourth aspect of the present invention, the MBT can be calculated accurately, and by using the MBT, the number of experimental steps and the adaptation period can be reduced, and the memory capacity can be reduced.

[0012]

Embodiments of the present invention will be described below. FIG. 3 is a system diagram of the internal combustion engine showing one embodiment. First, this will be described. Air is sucked from the air cleaner 2 into the combustion chamber of each cylinder of the internal combustion engine 1 mounted on the vehicle via the intake duct 3, the throttle valve 4, the intake manifold 5, and each intake valve 6. A fuel injection valve 7 is provided for each cylinder at each branch (or intake port) of the intake manifold 5.

The fuel injection valve 7 is an electromagnetic fuel injection valve (injector) that is energized by a solenoid and opens, and is de-energized and closed by being energized by an injection pulse signal from a control unit 13 described later. Then, the fuel is injected from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator to inject and supply the fuel.
Therefore, the fuel injection amount is controlled by the pulse width of the injection pulse signal.

A swirl control valve 8 is mounted on each branch (or intake port) of the intake manifold 5. The swirl control valve 8 can control the flow of air sucked into the combustion chamber by controlling the port cross-sectional area. An ignition plug 9 is provided in each combustion chamber of the internal combustion engine 1 to ignite a mixture by igniting a spark.

The exhaust gas from each combustion chamber of the internal combustion engine 1 is discharged from each exhaust valve 10 through an exhaust manifold 11.
It is led to the exhaust purification catalyst 12. An EGR device that guides a part of the exhaust gas from the exhaust manifold 11 and returns the exhaust gas to the intake manifold 5 via an EGR control valve is provided, but is not shown here.

The control unit 13 includes a CPU, an R
A microcomputer including an OM, a RAM, an A / D converter, an input / output interface, and the like;
Input signals from various sensors are received and arithmetic processing is performed based on the input signals to control operations of the fuel injection valve 7, the swirl control valve 8, the ignition plug 9, and the like. As the various sensors, a crank angle sensor 1 capable of detecting the engine rotational speed N together with the crank angle position from the rotation of the crankshaft or camshaft of the internal combustion engine 1
4, an air flow meter 15 for detecting the intake air flow rate Qa in the intake duct 3, a throttle sensor 16 for detecting the opening TVO of the throttle valve 4 (including an idle switch that is turned on when the throttle valve 4 is fully closed), and an internal combustion engine. A water temperature sensor 17 for detecting a cooling water temperature Tw of the engine 1, an O ₂ sensor 18 for outputting a signal corresponding to a rich / lean exhaust air-fuel ratio at an aggregate of the exhaust manifold 11, and the like are provided.

In the calculation processing of the fuel injection amount control, first, a basic injection pulse width RTp is calculated from the intake air flow rate Qa and the engine speed N by the following equation. RTp = K × Qa / N where K is a constant. Next, this is smoothed by a weighted average, and an injection pulse width Tp corresponding to the cylinder intake air amount is calculated as in the following equation.

Tp = RTp × FLOAD + Tp × (1−FLOAD) where FLOAD is a weighting coefficient. Next, this is corrected by the target fuel-air ratio correction coefficient TFBYA0, the air-fuel ratio feedback correction coefficient α, the invalid injection pulse width Ts, and the like, and the final injection pulse width Ti is calculated by the following equation.

Ti = Tp × TFBYA0 × α + Ts The target fuel-air ratio correction coefficient TFBYA0 is a value centered at 1.0, and is a value for enriching or leaning the air-fuel ratio. More specifically, TFBYA0 = Dm1
+ Ktw + Kas (where Dm1 is a fuel-air ratio correction coefficient depending on the engine speed and load, Ktw is a water temperature increase correction coefficient, K
as is calculated as a post-start increase correction coefficient).

When the final injection pulse width Ti is calculated, an injection pulse signal having the pulse width of Ti is output to each fuel injection valve 7 at a timing synchronized with the engine rotation, and fuel injection is performed. Next, the arithmetic processing of the ignition timing control (first embodiment) will be described with reference to the flowchart of FIG.

In step 1 (referred to as S1 in the drawing, the same applies hereinafter), the engine speed N, the injection pulse width Tp corresponding to the cylinder intake air amount representing the load, the water temperature Tw, the equivalence ratio φ (here, the equivalence ratio φ = The operation state such as the target fuel-air ratio correction coefficient TFBYA0) is read. Therefore, this part corresponds to the water temperature detecting means and the equivalent ratio detecting means. In step 2, the basic ignition timing is stored as ignition timing storage means for storing the basic ignition timing MADV [° BTDC] for each area of the engine operating state using the engine speed N and the injection pulse width Tp corresponding to the cylinder intake air amount as parameters. Referring to the map, the actual N,
The basic ignition timing MADV is searched from Tp.

In step 3, the water temperature Tw is set to a predetermined value Tw1.
It is determined whether or not the temperature is low (low temperature) and the equivalent ratio φ is equal to or more than a predetermined value φ1 (for example, a rich state of φ ≧ 1.2). If these conditions are not satisfied, go to step 4. In step 4, similarly to the related art, as shown in FIG. 5, the advance correction value TADV is set so as to advance according to the water temperature Tw such that the lower the water temperature, the more the angle is advanced.
The advance correction value TADV is searched from the actual Tw with reference to the table in which [°] is set.

On the other hand, if the conditions of water temperature Tw ≦ predetermined value Tw1 and equivalent ratio φ ≧ predetermined value φ1 are satisfied, the routine proceeds to step 5. In step 5, the advance correction value TADV is fixed to the advance correction value TADV1 when the water temperature Tw is the predetermined value Tw1 (TADV = TADV1; see FIG. 5). After these, go to step 6.

In step 6, the final ignition timing ADV [° BTDC] is calculated by adding the advance correction value TADV to the basic ignition timing MADV as in the following equation. ADV = MADV + TADV Therefore, steps 4 and 6 correspond to ignition timing water temperature correction means, and steps 3 and 5 correspond to advance correction value fixing means.

In step 7, this ignition timing A
The ignition control is performed so as to ignite at DV. Due to such control, as shown in FIG. 6, an error occurs between the control ignition timing (dotted line) and the required ignition timing (solid line) even in an area where the equivalence ratio φ = 1.2 and the water temperature Tw ≦ Tw1. do not do.

Next, a second embodiment of the calculation process of the ignition timing control will be described with reference to the flowcharts of FIGS. In this embodiment, in the MBT control using an arithmetic expression, that is, in a method in which the flame speed is calculated and the MBT is calculated and controlled based on the MBT control, the water temperature is corrected at the time of the calculation of the flame speed, so that the low water temperature When the angle is advanced, the water temperature correction coefficient is fixed in a low water temperature and over fuel state, thereby preventing instability of the engine and occurrence of abnormal noise due to over correction.

FIG. 7 shows a main routine of the ignition timing control, and FIG. 8 shows an MBT calculation routine. First, the main routine of FIG. 7 will be described. In step 11, the engine rotation speed N, the injection pulse width Tp corresponding to the cylinder intake air amount representing the load, the water temperature Tw, the equivalent ratio φ (here, the equivalent ratio φ
= Target fuel-air ratio correction coefficient TFBYA0), and operating states such as the swirl control valve opening SCVO are read. Therefore, this part corresponds to the water temperature detecting means and the equivalent ratio detecting means.

In step 12, it is determined whether or not the engine is idling. If not, the process proceeds to step 13.
In step 13, the MBT (optimum ignition timing) is calculated by another routine (FIG. 8) based on the operating state of the engine using an arithmetic expression, thereby obtaining the MBT calculated value MBTCAL.
Get.

In step 14, the MBT is calculated as follows:
If necessary, a trimming value TRM retrieved from the trimming map based on the operating state of the engine is subtracted (or added) from the calculated value MBTCAL to calculate a control ignition timing ADV. ADV = MBTCAL-TRM On the other hand, when idling, the routine proceeds to step 15, where a value on the more retarded side than MBT is set as the idling ignition timing ADV.

Thereafter, the routine proceeds to step 16, where ignition control is performed so as to ignite at the ignition timing ADV.
Next, the MBT calculation routine (10 ms job) in FIG. 8 will be described. The processing of steps 101 to 113, except for steps 107-A and 107-B, is performed as MBT calculation processing as disclosed in Japanese Patent Application Nos. 8-183637 and 8-23.
No. 8784, and the processing for fixing the advance correction value according to the present invention is described in step 10.
7-A and 107-B are added.

Therefore, first, in step 107-A, 1
The MBT calculation processing of steps 101 to 113 except for 07-B will be described. In step 101, using the injection pulse width Tp corresponding to the cylinder intake air amount, the charging efficiency ITAC is calculated by the following equation. ITAC = Tp / Tp100 (1) where Tp100 is T corresponding to 100% filling efficiency.
This is a fixed fixed value of p.

In step 102, using the target fuel-air ratio correction coefficient TFBYA0, a fuel weight equivalent coefficient FUELG is calculated by the following equation. FUELG = TFBYA0 / 14.5 (2) For example, at the stoichiometric air-fuel ratio, FUELG = 1.0 / 1
4.5, and when the air-fuel ratio is lean, 1.0 / 14.
It becomes a value smaller than 5.

In step 103, the fresh air ratio I, which is the ratio of the in-cylinder gas weight (sum of the new air weight GAIR and the self-residual gas weight GREG) to the new air weight (GAIR), is calculated.
Calculate TAN. Specifically, a predetermined map is searched and obtained from the charging efficiency ITAC and the engine speed N. In step 104, a predetermined table is searched from the charging efficiency ITAC to obtain the unburned gas density basic value DENS. The unburned gas density basic value DENS is a value that increases as the ITAC increases.

In step 105, a predetermined map is retrieved from the charging efficiency ITAC and the engine speed N to determine a laminar flame speed basic value FLML. The laminar flame velocity is the flame propagation velocity when the gas is stationary, that is, the flame propagation velocity when there is no flow (turbulence). Therefore,
The laminar flame speed basic value FLML is a value that increases as the ITAC increases under the condition that the engine speed N is constant, and increases as the engine speed N increases when the ITAC is constant.

In step 106, a predetermined table is first searched from the swirl control valve opening to determine a swirl control valve opening coefficient SCADMP. Next, using the swirl control valve opening coefficient SCADMP, a swirl correction coefficient SCVTF is calculated by the following equation. SCVTF = SCADMP × SCVK + 1.0 (3) where SCVK is a conformity coefficient.

The swirl correction coefficient SCVTF is a value indicating the rate at which the flame speed increases due to the increased turbulence when the swirl control valve is fully closed. Since this value is determined by the swirl control valve opening, it is 0 at the fully open position of the swirl control valve and 1 at the fully closed position. At the intermediate opening, the value calculated by linear interpolation is the swirl control valve opening coefficient SCAD.
Used as MP. Further, the adaptation coefficient SCVK is determined for each engine because it differs depending on the shape of the intake port of the engine.

In step 107, the water temperature Tw is calculated from FIG.
To find the water temperature correction coefficient TWHOS1, and to search the table of FIG. 10 to find the water temperature correction coefficient TWHOS2. In step 108, a predetermined table is searched from the target fuel-air ratio correction coefficient TFBYA0 to obtain the equivalence ratio correction coefficients RMDHS1 and RMDHS2.

In step 109, first, the charging efficiency IT
A predetermined map is retrieved from the AC and the engine speed N to determine a set EGR rate RATEGR. This set EGR rate R
ATEGR is calculated by: EGR gas flow rate / (new air flow rate + EG
R gas flow rate). Next, using the set EGR rate RATEGR, the correction E
Calculate the GR value EGRC.

EGRC = RATEGR × HK (4) Here, HK is a correction coefficient (constant value), and is adapted for each engine in order to correct a deviation between the actual EGR rate and the set EGR rate. . In step 110, the filling efficiency ITAC,
Corrected EGR value EGRC, fuel weight equivalent coefficient FUELG,
Using the fresh air ratio ITAN, the total gas mass in the cylinder (more precisely, the value per unit cylinder volume) MA
Calculate SSC.

MASSC = ITAC × [1 + EGRC + FUELG + (1-ITAN) / ITAN] (5) In this equation, the second, third, and fourth terms on the right side represent EGR, air-fuel ratio, and self-residual gas, respectively. The effect on the total gas mass in the cylinder is considered.

In step 111, the flame propagation speed FLV is calculated by the following equation using the laminar flame speed basic value FLML, the equivalent ratio correction coefficient RMDHS2, the water temperature correction coefficient TWHOS2, the swirl correction coefficient SCVTF, and the like. FLV = FLML × RMDHS2 × TWHOS2 × (1-A2 × EGR0) + FLMT × SCVTF × A3 (6) where A2: flame speed correction coefficient A3: flame speed correction coefficient EGR0: EGR correction coefficient FLMT: turbulent flame Speed basic value (fixed value).

In this equation, the first term on the right-hand side is the flame speed when there is no swirl, and the second term on the right-hand side is the improvement in the flame speed by swirl. In the first term on the right side, RMDHS
No. 2 considers the effect of the air-fuel ratio (target fuel-air ratio correction coefficient TFBYA0) on the laminar flame speed, and TWHOS2 considers the effect of the cooling water temperature Tw on the laminar flame speed.

The EGR correction coefficient EGR of the first term on the right side
0 is a value necessary for reducing the flame speed when performing EGR, and is calculated from the set EGR rate and the fresh air rate. The coefficient A2 is a constant value and is suitable for each engine. The turbulent flame velocity basic value FLMT in the second term on the right side is a value (fixed value) determined by performing a fishhook experiment in a fully closed state of the swirl control valve. Therefore, when the swirl control valve is at an intermediate opening that is not at the fully closed position, the swirl correction coefficient SCVTF is used to calculate F
LMT is corrected for weight reduction. The coefficient A3 is a value proportional to the engine speed N.

In step 112, using the unburned gas density basic value DENS, the equivalent ratio correction coefficient RMDHS1, and the water temperature correction coefficient TWHOS1, the unburned gas density RO is calculated by the following equation.
Calculate U. ROU = DENS × RMDHS1 × TWHOS1 (7) In this equation, TWHOS1 indicates the effect of the cooling water temperature Tw on the unburned gas density, and RMDHS1 indicates the air-fuel ratio (target fuel-air ratio correction coefficient TFBYA0) of the unburned gas. The effect on the density is taken into account.

In this way, the total gas mass M in the cylinder
After calculating the ASSC, the flame speed FLV, and the unburned gas density ROU, the routine proceeds to step 113. In step 113,
Using these, the MBT operation value MBTCA is calculated by the following equation.
Calculate L [° BTDC]. MBTCAL = [B1 + A1 × MASSC / (ROU × FLV)] × B2-B3 (8) where B1: ignition delay time B2: conversion variable from time to crank angle B3: crank angle correction coefficient for MBTCAL calculation.

A1 = ρ0 × Vcyl, where ρ0 is the standard air density and Vcyl is the stroke volume. Therefore, A1 × M
ASSC is the total air weight in the cylinder. MBT is the ignition timing when the crank angle position at which the in-cylinder pressure at the time of combustion becomes the maximum is set at a predetermined crank angle (10 ° to 15 °) after the compression top dead center. In this case, conventionally, MBT is generally adopted as the basic ignition timing,
While a map of the basic ignition timing using the engine speed and the load as parameters is determined in advance by a suitable experiment, the MBT is quantified by an arithmetic expression here.

In the equation (8), the value obtained by dividing A1 × MASSC, which is the total gas weight in the cylinder, by the product of the unburned gas density ROU and the flame speed FLV is such that the flame reaches all the unburned gas in the cylinder. In terms of time (burning time), the unit is logically [ms]. A value obtained by adding the ignition delay time B1 [ms] to the combustion time is converted into a crank angle unit by the conversion variable B2, thereby determining an ignition advance value at which MBT is obtained.

According to this equation, when the flame speed FLV is constant, the time required for combustion increases as the total gas weight in the cylinder increases, and accordingly, the value of MBTCAL increases accordingly, and the total gas weight in the cylinder increases. When is constant, the time required for combustion decreases as the flame speed FLV increases,
The value of MBTCAL moves accordingly to the retard side. Furthermore, even if the time required for combustion is constant, the crank angle section corresponding to that time varies depending on the rotation speed, and the higher the rotation speed, the more MBTCAL must be set on the advance side. N. B1, B
3 is a constant value, which is suitable for each institution.

Here, MB using the basic ignition timing map
In the T control method, a great deal of adaptation experiments are required corresponding to the representative points of the engine speed and the load. On the other hand, the MBT control method based on the original calculation formula using the intake air flow rate and the speed is basically used. Then, it is possible to adapt the MBT calculation formula with few experiments, shorten the development period,
Since the memory of the control unit is reduced, the cost can be reduced.

In the above-mentioned MBT calculation processing, the flame speed FLV is calculated in step 111 based on the value obtained by multiplying the laminar flame speed basic value FLML by the water temperature correction coefficient TWHOS2 as shown in the above equation (6). , Step 113
, At least the flame speed FL as in the equation (8).
On the basis of V, the MBT calculation value MBTCAL is calculated so that the smaller the flame speed FLV, the more advanced the angle. The lower the water temperature, the lower the flame speed FL (see FIG. 10).
By calculating V smaller, MBT is calculated on the advance side.

Therefore, step 111 corresponds to the flame speed calculating means, step 113 corresponds to the MBT calculating means, and step 107 corresponds to the water temperature correction coefficient setting means as the ignition timing water temperature correcting means. . However, when the water temperature is low and the fuel is over-fueled, the water temperature correction coefficient TWHOS
If 2 becomes too small, an over-advance angle will occur.

In step 107 (water temperature correction coefficient T
WHOS2 search processing), and then step 107-
A, 107-B are added. In step 107-A, it is determined whether or not the water temperature Tw is equal to or lower than a predetermined value Tw1 (low temperature) and the equivalence ratio φ is equal to or higher than a predetermined value φ1 (for example, a rich state of φ ≧ 1.2). Then, when this condition is satisfied, the step 107-B is executed.

In step 107-B, a water temperature correction coefficient TWHOS2 as an advance correction value is set to a predetermined value Tw.
1 is fixed to the water temperature correction coefficient TWHOS21 (T
WHOS2 = TWHOS21; see FIG. 10). Therefore,
Steps 107-A and 107-B correspond to water temperature correction coefficient fixing means as advance angle correction value fixing means.

In this way, it is possible to prevent instability of the engine and generation of abnormal noise due to overcorrection in a low water temperature and overfuel state.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a first configuration of the present invention.

FIG. 2 is a functional block diagram showing a second configuration of the present invention.

FIG. 3 is a system diagram of an internal combustion engine showing one embodiment of the present invention.

FIG. 4 is a flowchart of ignition timing control according to the first embodiment;

FIG. 5 is a diagram showing a lead angle correction value table;

FIG. 6 is a diagram showing the effect of the present invention.

FIG. 7 is a flowchart of ignition timing control according to a second embodiment.

FIG. 8 is a flowchart of an MBT calculation routine.

FIG. 9 is a diagram showing a water temperature correction coefficient table;

FIG. 10 is a diagram showing a water temperature correction coefficient table.

FIG. 11 is a diagram showing a lead angle correction value table of a conventional example.

FIG. 12 is a diagram showing a problem of the conventional example.

[Description of Signs] 1 Internal combustion engine 4 Throttle valve 7 Fuel injection valve 8 Swirl control valve 9 Spark plug 13 Control unit 14 Crank angle sensor 15 Air flow meter 17 Water temperature sensor

Claims (4)

[Claims] 1. A water temperature detecting means for detecting a cooling water temperature of an engine, and an ignition timing water temperature correcting means for setting an advance correction value so as to advance the lower water temperature in accordance with the cooling water temperature and correcting an ignition timing, In an ignition timing control device for an internal combustion engine comprising: an equivalence ratio detecting means for detecting an equivalence ratio expressed by fuel mass / air mass; and when the cooling water temperature is equal to or lower than a predetermined value and the equivalence ratio is equal to or higher than a predetermined value, An ignition timing control device for an internal combustion engine, comprising: an advance correction value fixing means for fixing an advance correction value by the ignition timing water temperature correction means to an advance correction value when the cooling water temperature is a predetermined value. . And a basic ignition timing storing means for storing a basic ignition timing using an engine speed and a load as parameters, wherein the ignition timing water temperature correction means stores the basic ignition timing retrieved from the basic ignition timing storage means. 2. The ignition timing control device for an internal combustion engine according to claim 1, wherein the ignition timing for control is calculated by adding or subtracting an advance correction value. 3. A flame speed calculating means for calculating a flame speed based on a value obtained by multiplying a basic value of a laminar flame speed by a water temperature correction coefficient, and wherein at least based on the flame speed, the flame speed is advanced as the flame speed becomes lower. MBT calculating means for calculating an MBT (optimal ignition timing) having the best fuel efficiency, wherein the ignition timing water temperature correction means sets the water temperature correction coefficient as an advance correction value in accordance with the cooling water temperature as the water temperature decreases. Water temperature correction coefficient setting means to set a small, the advance correction value fixing means, the cooling water temperature is below a predetermined value,
And a water temperature correction coefficient fixing means for fixing a water temperature correction coefficient by the water temperature correction coefficient setting means to a water temperature correction coefficient when the cooling water temperature is at a predetermined value when the equivalent ratio is equal to or more than a predetermined value. 2. The ignition timing control device for an internal combustion engine according to claim 1. 4. The MBT calculating means adds a predetermined ignition delay time to a value obtained by dividing the total gas weight in the cylinder by the unburned gas density and the flame speed, and uses the added value as a crank angle according to the engine speed. 4. The ignition timing control apparatus for an internal combustion engine according to claim 3, wherein the apparatus calculates the MBT by converting.