JP2002195141A - Device for controlling ignition timing of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling ignition timing of an internal combustion engine that can reduce a wasteful phase lag when the ignition timing is corrected according to an engine temperature and improve torque during engine cold and fuel economy. SOLUTION: The MBT basic map values and the knock basic map values influenced differently by changes in water temperature and intake air temperature are calculated separately S210, 230. The basic map values are corrected by an MBT water temperature correction term and an MBT intake air temperature correction term which are calculated separately and the MBT ignition timing is calculated S220. The knock basic map values are corrected by a knock water temperature correction term and a knock intake air temperature correction term which are calculated separately and the knock ignition timing is calculated S240. Thereby values which has not been advanced in the prior art can be advanced. Particularly during engine cold, the final ignition timing can be set on the basis of the knock basic map values changing largely to an advancing side than the MBT basic map values as the engine temperature gets lower.

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 controlling an ignition timing according to an operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine in which an air / fuel mixture is compressed and ignited by a spark plug, a spark plug is generally set to an optimum ignition timing according to the operating condition of the engine, for example, the engine speed and load. It is designed to work. In such an ignition timing control device for an internal combustion engine, in order to control the ignition timing in accordance with the operation state, for example,
The basic ignition timing is obtained based on the engine speed and load, and a required ignition timing is calculated by adding a water temperature correction amount corresponding to the cooling water temperature to the ignition timing. The basic ignition timing is obtained by referring to a map based on the engine speed and load.

[0003] In the "basic map", the values on the retard side of the MBT and the minute knock point, which change according to the rotational speed and the load, are embedded so that torque is generated and knocking does not occur. I have. That is, if the MBT is more retarded than the slight knock point, the value of the MBT is entered into the map, and if the slight knock point is more retarded than the MBT, the value of the slight knock point is entered into the map. It is. Thus, in the "basic map" for obtaining the basic ignition timing, either the value of the MBT or the value of the slight knock point is entered according to each operating state. Here, “MBT” is the best ignition timing (Minimum advance for th
e Best Torque). Also, the "small knock point"
“Ignition timing in a state where minute knocking is generated, and has substantially the same meaning as“ knock limit ignition timing ”.

The above “basic map” will be further described with reference to a graph shown in FIG. This graph shows that M at a certain rotation speed (equal rotation) with respect to a change in the load of the engine.
The transition of the BT, the slight knock point, and the basic ignition timing are shown. In addition, in the same graph, M
In BT and transition one-dot chain line and broken fine knock point, it is shown respectively the trend of the basic ignition timing by a solid line. When the load is lower than a certain value A, knocking is less likely to occur, and the value of MBT is more retarded than the slight knock point. Therefore, the basic map contains the value of MBT as the basic ignition timing. is there. On the other hand, when the load is higher than a certain value A, knocking is liable to occur.
Since it is on the more retarded side than T, the basic map contains the value of the slight knock point as the basic ignition timing. Thus, the map value of the basic ignition timing when the load changes at a certain rotational speed is set as shown by the solid line in FIG.

[0005] Next, description will be given water temperature correction amount when the water temperature correction according to the cooling water temperature (water temperature) to the basic ignition timing determined as described above. In the conventional ignition timing control device for an internal combustion engine, the water temperature is corrected so that the basic ignition timing is advanced as the water temperature is lower. This is because the lower the water temperature, the slower the combustion speed and the less likely knocking occurs. In this ignition timing control device, the water temperature correction amount for the basic ignition timing is calculated with reference to one "water temperature correction map" according to the water temperature. In this water temperature correction map, although the effect of the change in water temperature on the MBT and the effect on the fine knock point are different, the smaller value of the advance amount with respect to the change in water temperature is included as the water temperature correction amount. The graph of FIG. 6 shows that as the water temperature decreases, the fine knock point shifts to the advanced side more than the MBT, that is, the slight knock point is more greatly affected by the change in water temperature than the MBT. Is shown.

[0006]

The above prior art has the following problems. (1) In order to calculate the basic ignition timing, the MBT and the slight knock point are not divided. For this reason, when performing the water temperature correction for the basic ignition timing, the water temperature correction amount is calculated from one water temperature correction map. Along with this, in the water temperature correction map, to the influence of impact and fine knocking point MBT undergoes a change in water temperature experienced by different, smaller values of the amount advanced in accordance with the temperature change (advance amounts) That is, the value of the amount of advance of the MBT with respect to the change in water temperature is entered as the water temperature correction amount. This will be described with reference to FIG. FIG.
In the operation state where the water temperature is T ° C. and the load is a value B,
The basic ignition timing indicated by the solid line in FIG.
In the same operating state, when the water temperature drops by a certain temperature from T ° C., the basic ignition timing at T ° C. indicated by point a, the amount of MBT advance (water temperature correction) corresponding to the temperature drop from T ° C. Is added, and the required ignition timing indicated by the point b is calculated.

However, in this case, although the fine knock point can be advanced from the point a to the point c, it is not advanced by (c−b), and the unnecessary retard is performed by that amount. Will be. As a result, the torque and the fuel efficiency are reduced accordingly. These problems become more pronounced when the engine is cold. That is, as shown in the graph of FIG. 6, as the water temperature becomes lower, the fine knock point shifts to the advanced side more than the MBT, so that the cold (C-b) advance amount increases as the water temperature becomes lower. As a result, the amount of unnecessary retardation increases, and the torque and the fuel efficiency are greatly reduced.

(2) In the basic map for calculating the basic ignition timing, both the value of the MBT and the value of the slight knock point are mixed as the basic ignition timing according to each operation state. The map values such two values (values of MBT values and fine knock point) are mixed, will be the basic ignition timing corresponding to a change in load at constant rotation as shown in Figure 5, over the entire operating range, predetermined It is necessary to make actual measurements for each rotation speed. Therefore, when creating the basic map, it is very difficult to adjust the basic ignition timing according to the operating state, and it takes a lot of time to create the map.

(3) Conventionally, the ignition timing has not been corrected in accordance with the intake air temperature much. This is because it is difficult to reflect the intake air temperature on the ignition timing. As described above, since the influence of the intake air temperature is not reflected in the ignition timing, although the intake air temperature is low and knocking does not easily occur,
There is a case where the angle is too retarded by the knock control. For example, when the engine is stopped and restarted after a while, if the intake air temperature is high, knocking is likely to occur, the angle is retarded by knock control, and this value (knock control amount) is memorized as a learning value. As a result, even when the engine is started normally thereafter and the intake air temperature is low, knocking is not likely to occur, but the learned value of knock is reflected, so that there is a problem that torque and fuel efficiency are reduced. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce unnecessary retardation when correcting ignition timing in accordance with engine temperature, and to reduce torque during cold operation. Another object of the present invention is to provide an ignition timing control device for an internal combustion engine that improves fuel economy. Another object of the present invention is to facilitate adaptation of the basic ignition timing according to each operation state, and to greatly reduce the labor for creating a map for the basic ignition timing. Further, another object of the present invention is to prevent unnecessary retardation at the time of high temperature start and to improve torque and fuel efficiency at the time of high temperature start.

[0011]

The means for achieving the above object and the effects thereof will be described below. The invention according to claim 1, in an ignition timing control apparatus for an internal combustion engine for controlling the ignition timing in accordance with the operating condition of the internal combustion engine, a basic ignition timing in accordance with the operating conditions, the most output of leaving ignition timing basic Basic ignition timing calculating means for separately calculating an MBT ignition timing and a basic knock ignition timing which is a knock limit ignition timing; a correction value for the basic MBT ignition timing and a correction value for the basic knock ignition timing And an ignition timing correction means for separately obtaining the correction values for the two ignition timings and correcting the two ignition timings with the two correction values. And a final ignition timing setting means for setting the final ignition timing based on the above.

[0012] According to this configuration, the basic MBT ignition timing and the basic knock ignition timing, which are different from each other due to the change in the engine temperature, are separately obtained, and the two ignition timings are respectively determined by dedicated correction values obtained separately according to the engine temperature. to correct. For this reason, in the above-described conventional technique, the angle that has not been advanced can be advanced. In particular, when cold, it is possible to set a final ignition timing based on the basic knock ignition timing which varies greater the advance side from the basic MBT ignition timing as the engine temperature decreases. Therefore, it is possible to reduce a useless retardation when correcting the ignition timing according to the engine temperature, and it is possible to increase a torque in a cold state and improve fuel efficiency.

According to a second aspect of the present invention, in the ignition timing control apparatus for an internal combustion engine according to the first aspect, the basic ignition timing calculating means converts the basic MBT ignition timing into an MBT basic map according to the operating state. And the basic knock ignition timing is determined with reference to a basic knock map in accordance with the operating state.

According to this configuration, two maps, one for the basic MBT ignition timing and the other for the basic knock ignition timing, are separately prepared as maps for calculating the ignition timing according to the operating state. . For this reason, in the MBT basic map, only the MBT value corresponding to each operation state is entered as the basic MBT ignition timing, and in the knock basic map,
Only the value of the knock limit ignition timing corresponding to each operation state may be entered as the basic knock ignition timing. Therefore,
Both ignition timings can be individually adjusted according to each operation state, and both ignition timings can be easily adapted to each operation state.

According to a third aspect of the present invention, in the ignition timing control apparatus for an internal combustion engine according to the first or second aspect, the ignition timing correction means corrects a water temperature for the basic MBT ignition timing in accordance with a cooling water temperature. obtains a value as the water temperature correction value for the basic knock ignition timing separately, the basic MBT at the both correction value
The gist is to correct the ignition timing and the basic knock ignition timing respectively.

According to this configuration, the basic MBT ignition timing and the basic knock ignition timing are respectively corrected by the exclusive water temperature correction values separately obtained according to the cooling water temperature, so that the prior art is not advanced. The minute can be advanced. In particular, when cold, the lower the cooling water temperature, the more the basic M
The final ignition timing can be set based on the basic knock ignition timing that greatly changes to the advance side from the BT ignition timing. Therefore, it is possible to reduce unnecessary retardation when correcting the ignition timing according to the cooling water temperature, and it is possible to increase the torque and improve the fuel efficiency in a cold state.

According to a fourth aspect of the present invention, in the ignition timing control apparatus for an internal combustion engine according to the first or second aspect, the ignition timing correction means includes an intake air temperature for the basic MBT ignition timing in accordance with the intake air temperature. calculated separately the correction value and the intake air temperature correction value for the basic knock ignition timing, the basic MB at the both correction value
The gist is to correct the T ignition timing and the basic knock ignition timing respectively.

According to this configuration, the basic MBT ignition timing and the basic knock ignition timing are each corrected by the dedicated intake air temperature correction value separately obtained according to the intake air temperature. Can be advanced. In particular, when cold, the lower the cooling water temperature, the more the basic M
The final ignition timing can be set based on the basic knock ignition timing that greatly changes to the advance side from the BT ignition timing. Therefore, it is possible to reduce the useless retard when the correction according to the intake air temperature relative to the ignition timing, it is possible to improve the increase and fuel economy of the torque during cold. Also, since the intake air temperature is reflected on both ignition timings,
In the knock control, it is not necessary to consider the intake air temperature. For this reason, it is possible to prevent the ignition control from being excessively retarded by the knock control at the time of the high-temperature start as in the above-described related art.
Therefore, it is possible to reduce the increase in the torque and the improvement in the fuel efficiency at the time of the high temperature start.

According to a fifth aspect of the present invention, in the ignition timing control device for an internal combustion engine according to the first or second aspect, the ignition timing correction means is provided for the basic MBT ignition timing and the basic MBT ignition timing in accordance with a cooling water temperature. Each water temperature correction value for knock ignition timing is separately obtained, and the basic M
The intake air temperature correction values for the BT ignition timing and the basic knock ignition timing are separately obtained, and the basic MB
The gist is to correct the T ignition timing and the basic knock ignition timing respectively.

According to this configuration, the basic MBT ignition timing and the basic knock ignition timing are each corrected by both the dedicated water temperature correction value and the intake air temperature correction value. The torque at the time can be increased and the fuel efficiency can be improved. Further, since the intake air temperature is reflected in the correction of the basic MBT ignition timing and the basic knock ignition timing, it is possible to reduce the increase in the torque and the improvement in the fuel efficiency at the time of the high temperature start as in the invention according to the fourth aspect. it can.

According to a sixth aspect of the present invention, in the ignition timing control apparatus for an internal combustion engine according to any one of the first to fifth aspects, the ignition timing correction means is configured to control the basic timing according to a factor that changes knocking. and ignition timing control device gist of an internal combustion engine according to any one of claims 1 to 5, wherein the correcting the knock ignition timing.

According to this structure, a plurality of maps are prepared for the basic knock ignition timing, which are independent of the map for the basic MBT ignition timing, for each factor. Correction can be easily dealt with. The factors include, for example, that the standards for gasoline octane number differ from country to country, and that the intake air temperature conditions for measuring the basic knock ignition timing differ from country to country.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an engine 11 as a vehicular internal combustion engine to which the internal combustion engine ignition timing control device according to the present embodiment is applied.

The engine 11 includes a cylinder head 12 and
A cylinder block 14 in which a plurality of cylinders 13 (only one cylinder is shown in FIG. 1) is provided. A piston 15 is provided in each cylinder 13 so as to be able to reciprocate. A combustion chamber 16 is formed by the piston 15, the inner wall of the cylinder 13, and the cylinder head 12. Reference numeral 17 denotes a crankshaft as an output shaft of the engine 11, and reference numeral 18 denotes a connecting rod for converting a reciprocating motion of the piston 15 into a rotational motion of the crankshaft 17.

[0025] The intake port 20 of each cylinder flows through the outside air sucked from an air cleaner (not shown) in the intake passage 21. An injector 22 provided for each cylinder injects fuel to each intake port 20. The mixture of the outside air and the fuel taken into the intake passage 21 is introduced into the combustion chamber 16 when the intake port 20 is opened by the intake valve 24 of each cylinder. By operating the ignition plug 38 provided for each cylinder, the air-fuel mixture explodes in the combustion chamber 16.
The piston 15 operates by burning, and the driving force of the engine 11 is obtained. Thereafter, when the exhaust port 23 is opened by the exhaust valve 25 of each cylinder, the burned gas is discharged from the combustion chamber 16 to the outside via the exhaust passage 26 as the exhaust gas.

A throttle valve 29 provided in the middle of the intake passage 21 operates in conjunction with operation of an accelerator pedal (not shown) to open and close the intake passage 21. The operation of the throttle valve 29, the intake air amount is adjusted relative to the intake passage 21.

The throttle valve 2 in the intake passage 21
An intake air temperature sensor 30 provided on the upstream side of 9 detects the temperature (intake air temperature th) of the air taken into the intake passage 21 and outputs a signal corresponding to the detected temperature. An air flow meter 31 provided near the air cleaner in the intake passage 21 detects the amount of intake air in the intake passage 21 and outputs a signal corresponding to the amount. A throttle sensor 32 provided near the throttle valve 29 detects the opening (throttle opening) of the valve 29 and outputs a signal corresponding to the opening.

A water temperature sensor 33 provided in the cylinder block 14 detects a temperature of cooling water (cooling water temperature thw) for cooling the block 14, and outputs a signal corresponding to the temperature. Further, knock sensor 34 provided in cylinder block 14 detects vibration including knocking generated in engine 11, and outputs a knock signal according to the magnitude of the vibration. The rotation speed sensor 35 provided near the crankshaft 17 is connected to the crankshaft 1.
7, the rotation speed of the engine 11 (engine rotation speed NE) is detected, and a signal corresponding to the detected rotation speed is output.

Further, the engine 11 is controlled by an electronic control unit (hereinafter, ECU hereinafter) igniter 36 is provided which is controlled by 40. This igniter 36 is EC
Ignition signal (igniter energization signal) output from U40
The current flowing through the primary coil of the ignition coil 37 is turned on and off based on the above. Ignition coil 3
Reference numeral 7 causes a spark discharge to occur in the spark plug 38 by the high voltage induced on the secondary coil side when the current flowing through the primary coil is cut off, thereby causing the air-fuel mixture to ignite. Thus, the ignition timing of the ignition plug 38 is controlled by the igniter 36
Is determined by an igniter energization signal output from the ECU 40.

The detection signals output from the intake air temperature sensor 30, throttle sensor 32, water temperature sensor 33, knock sensor 34, rotational speed sensor 35, etc.
Input to 40. The ECU 40 includes the above-described sensors 3
Based on detection signals from various sensors including 0, 32 to 35, fuel injection amount control including air-fuel ratio control, ignition timing control including knock control, and the like are executed. Further, the ECU 40 includes a memory 41 for storing a program for executing the fuel injection amount control and the ignition timing control, an arithmetic map, data calculated at the time of executing the control, and the like. The following six maps are stored in the memory 41 of the present embodiment as a part of the calculation map.

(1) Engine speed NE and load factor KL
Based on the above, the ignition timing at which the torque is highest (MBT above)
An MBT basic map value (ambt _- map) as a basic MBT ignition timing, which is a basic MBT ignition timing, is calculated as one basic ignition timing according to the operating state (FIG. 2).
(A)). In this map, as shown in FIG. 5, measured values of the MBT that change according to the load at the same rotation are entered for each predetermined rotation speed. The MBT basic map value in the rotation speed region during that period is calculated by linear interpolation.

(2) Engine speed NE and load factor KL
Based on the above, the minute knock point (knock limit ignition timing)
The basic MBT map (FIG. 2) for calculating the basic knock map value (aknok _- map) as the basic knock ignition timing as another basic ignition timing according to the operating state.
(B)). In this map, as shown in FIG. 5, actual measured values of fine knock points that change in accordance with the load at equal rotations are entered for each predetermined rotation speed. The MBT basic map value in the rotation speed region during that period is calculated by linear interpolation.

(3) According to the water temperature (thw), the MB
An MBT map 1 for calculating an MBT water temperature correction term (acold) as a water temperature correction value of the T basic map value. In this map, as shown in the transition of the MBT indicated by the solid line C in FIG. 6, the advance amount (correction amount) with respect to the MBT basic map value set according to the water temperature so that the advance amount increases as the water temperature decreases. Has been put.

(4) A knock water temperature correction term (ath) as a water temperature correction value for the knock basic map value according to the water temperature.
knock map 1 for calculating wknok). In this map, as shown in the transition of the fine knock point indicated by the solid line D in FIG. 6, the advance amount (correction amount) with respect to the knock basic map value set according to the water temperature is set so that the advance amount increases as the water temperature decreases. Amount).

(5) According to the intake air temperature (tha), the above M
An MBT map 2 for calculating an MBT intake air temperature correction term (athambt) as an intake air temperature correction value for a BT basic map value. In this map, as shown in the transition of the MBT shown in FIG. 7, the advance amount (correction amount) for the MBT basic map value set according to the intake air temperature is set so that the advance amount increases as the intake air temperature decreases. There is.

(6) A knock map 2 for calculating a knock intake air temperature correction term (athaknok) as an intake air temperature correction value for the knock basic map value in accordance with the intake air temperature. In this map, as shown in the transition of the fine knock point shown in FIG. 7, the advance amount (correction amount) with respect to the knock basic map value set according to the intake air temperature is set so that the advance amount increases as the intake air temperature decreases. ) are put. The “ignition timing control” executed by the ECU 40 refers to controlling the igniter 36 in accordance with the operating state of the engine 11 to operate each ignition plug 38 to set the ignition timing of the air-fuel mixture in each combustion chamber 16. It is to control. “Knock control” means that knocking occurrence is determined based on a detection value of knock sensor 34 and ignition timing is retarded from optimal ignition timing based on the determination result to control knocking occurrence. It is to be.

Next, the ignition timing control executed by the ECU 40 will be described with reference to FIGS. FIG. 3 shows the ECU 4
0 correction term calculating routine executed in, Fig. 4 is ECU40
Are respectively shown.

The ECU 40 executes the temperature correction term calculation routine shown in FIG. 3 separately from the ignition timing calculation routine shown in FIG. This is because the temperatures (cooling water temperature, intake air temperature) used in the temperature correction term calculation routine change slowly, so that it is not necessary to make the control cycle of the routine as fast as the ignition timing calculation routine. The ECU 40 processes these two routines in parallel.

The temperature correction term calculation routine shown in FIG. 3 is repeatedly executed at a predetermined control cycle (for example, about 65 ms). In this temperature correction term calculation routine, first, in step S110, the MBT water temperature correction term (acold) as the water temperature correction value for the basic MBT ignition timing is determined according to the current water temperature (thw) detected by the water temperature sensor 33.
It is calculated with reference to the T map 1 (the above map (3)). Thereafter, the process proceeds to step S120.

In step S120, an MBT intake temperature correction term (athambt) as an intake temperature correction value for the basic MBT ignition timing is determined based on the current intake temperature (tha) detected by the intake temperature sensor 30. It is calculated with reference to (Map (5) above). Thereafter, the process proceeds to step S130.

In step S130, a knock water temperature correction term (at
hwknok) is calculated with reference to knock map 1 (map (4) above) according to the current cooling water temperature (water temperature thw) detected by water temperature sensor 33. Thereafter, the process proceeds to step S140.

In step S140, a knock intake air temperature correction term (athaknok) as an intake air temperature correction value for the basic knock ignition timing is determined according to the current intake air temperature (tha) detected by the intake air temperature sensor 30. It is calculated with reference to (Map (6) above). After this, FIG.
Is temporarily terminated.

Next, a description will be given of an ignition timing calculation routine shown in FIG. This routine is executed in a predetermined control cycle.
For example, in the case of a four-cylinder internal combustion engine, the process is executed at every 180 ° crank angle.

In this ignition timing calculation routine, first, in step S210, M as the basic MBT ignition timing
The BT basic map value (ambt _- map) is
The calculation is performed by referring to the MBT basic map (map (1)) shown in FIG. Thereafter, the process proceeds to step S220.

In step S220, the MBT ignition timing (ambt) is calculated by the following equation (1). ambt = (ambt _- map) + acold + athambt (1) Thus, the MBT ignition timing (ambt) is calculated based on the MBT basic map value (ambt _- map), the MBT water temperature correction term (acold) and the MBT intake temperature correction term (athamb).
t) and is corrected. Thereafter, step S23
Go to 0. In step S230, a knock basic map value (akkn _- ma) as a basic knock ignition timing
p) is calculated according to the operating state of the engine 11 with reference to the knock basic map (map (2)) shown in FIG. Thereafter, the process proceeds to step S240.

In step S240, a knock ignition timing (aknok) is calculated by the following equation (2). aknok = (aknok _- map) + athwknok + athaknok (2) Thus, the knock ignition timing (aknok) is based on the knock basic map value (aknok _- map), the knock water temperature correction term (athwknok) and the knock intake temperature correction term (a).
aknok). Thereafter, the process proceeds to step S250.

In step S250, the engine 11
It is determined whether or not the operation state is idle ON. When the accelerator pedal is not operated and an ON signal is output from an idle switch (not shown) (step S25)
If it is 0 (YES), the process proceeds to step S260. If the pedal is operated and the OFF signal is output from the idle switch (NO in step S250), the process proceeds to step S270.

When the routine proceeds to step S260, the basic ignition timing (absen) for idling ON is set as the basic ignition timing (abse), and the routine proceeds to step S280. On the other hand, when the process proceeds to step S270, the MBT ignition timing (amb) calculated in step S220 is calculated.
t) and the ignition timing on the retard side is selected from among the knock ignition timings (aknok) calculated in step S240, and the selected ignition timing is used as the basic ignition timing (abse).
And the process proceeds to step S280.

In step S280, the basic ignition timing is corrected by adding the VVT correction amount (avvt) and the knock control amount (aknk) to the basic ignition timing (abse) set in step S260 or step S270. The value is set as the required ignition timing (acal).

Here, the "VVT correction amount" is determined by the ECU 40
Drive control of a variable valve timing mechanism (not shown) to reduce the compression ratio.
4 or the retard amount when the valve timing of the exhaust valve 25 is retarded. The “knock control amount” is a retard amount when the ignition timing is retarded from the optimal ignition timing by the knock control executed by the ECU 40 to control the occurrence of knocking.

After step S280, step S280
Proceed to. In this step S280, of the required ignition timing (acal) calculated in step S280 and the various control amounts for the ignition timing, such as the amount of retardation when a retardation request is made based on various conditions, The retard value is set as the final ignition timing (aop). As various control amounts, for example, an advance smoothing control buffer (abu
f), an acceleration retard control amount (acc), a fuel cut return retard amount (afc), a transient retard amount (atrn), a catalyst warm-up retard amount (acat), and the like.

According to step S280, during the steady operation without the above-mentioned retardation request and the above-mentioned various control amounts for the ignition timing, the required ignition timing (acal) set at step S280 is used as the final ignition timing (aop). Is set. Based on the required ignition timing (aop), the ECU
Determines the time OFF of the ignition signal output from the 40 to the igniter 36 (the igniter energization signal), the OFF current at flows through the primary coil of the ignition coil 37 is shut off, the ignition by the spark plug 38 is performed. On the other hand, when there is any of the above various control amounts, for example,
There is a fuel cut return retard amount (afc) at the time of fuel cut return, and the retard amount is the required ignition timing (a
If the value is on the retard side from cal), the return retard amount is set as the final ignition timing (aop). As described above, ignition by the ignition plug 38 is performed based on the return retardation amount.

[0053] Step S210 and S23
0 corresponds to the basic ignition timing calculation means of the present invention. Steps S110 to S140 and step S220
Step S240 corresponds to the ignition timing correction means of the present invention. Steps S270 to S2
90 corresponds to the final ignition timing setting means of the present invention.

As described above, according to the present embodiment, the following operation and effect can be obtained. (B) The basic MBT map value (MBT value) and the basic knock map value (small knock point or knock limit ignition timing), which are different from each other due to changes in the engine temperature (water temperature and intake air temperature),
In steps S210 and S230, they are obtained separately. Also, MB
The T basic map value is stored in step S110 and step S1.
The MBT ignition timing is calculated by correcting the MBT water temperature correction term and the MBT intake air temperature correction term separately obtained in step 20 (step S220). Then, the knock basic map value is corrected by the knock water temperature correction term and the knock intake air temperature correction term separately obtained in step S130 and step S140, and the knock ignition timing is calculated (step S2).
40).

[0055] By this configuration, in FIG. 5 described above, the load at a certain rotational speed is the operating state of B, the water temperature is T ° C.
In the prior art, when the temperature is lowered by a certain amount, the water temperature is advanced only from the basic ignition timing indicated by the point a to the ignition timing indicated by the point b. On the other hand, in the present embodiment, under the same condition, the angle is advanced from the knock basic map value indicated by point a to the knock basic map value indicated by point c by temperature correction (water temperature and intake air temperature correction). In this way, in the above-described conventional technique, the advance amount of (c−b) is suppressed in the above-described operation state, and the useless retard is performed by that amount.
On the other hand, in the present embodiment, the angle can be advanced from the point a to the point c. Therefore, it is possible to reduce a useless retardation when correcting the ignition timing according to the engine temperature, and it is possible to increase a torque in a cold state and improve fuel efficiency.

(B) In particular, as the MBT basic map value (fine knock point) decreases, the knock basic map value (M
Since transitions greater the advance side than BT) (see FIG. 6), the advance amount of the more the cold above (c-b) is increased, it is possible to significantly improve torque and fuel economy. (C) As a map for calculating an ignition timing according to an operation state, an MBT basic map (see FIG. 2A) and a knock basic map (see FIG. 2B) are separately prepared. I have. For this reason, in the MBT basic map, only the MBT value corresponding to each operation state is entered as the MBT basic map value, and in the knock basic map, only the value of the knock limit ignition timing corresponding to each operation state is used as the knock basic map value. Just put it in. Thereby, as in the above-described prior art, 2
The map value in which the values of the types (the value of the MBT and the value of the fine knock point) are mixed is used for the basic ignition timing corresponding to the change in the load at the constant rotation as shown in FIG.
There is no need to make measurements by actually measuring at each predetermined rotation speed. Therefore, both map values (basic ignition timing) can be individually adapted according to each operation state, and both map values as the basic ignition timing can be easily adapted to each operation state. Significantly eliminates the need to create maps.

(D) Since the intake air temperature is reflected on the MBT basic map value and the knock basic map value (steps S220 and S240), an appropriate ignition timing is set according to the intake air temperature even if the water temperature is high. be able to. As a result, it is possible to prevent an excessive retardation due to knock control due to a high water temperature in an operation state in which the intake air temperature is low and knocking is unlikely to occur, as in the above-described related art. Therefore, it is possible to reduce the increase in the torque and the improvement in the fuel efficiency at the time of the high temperature start.

(E) The MBT basic map value and the knock basic map value are corrected using both the dedicated water temperature correction term and the intake air temperature correction term (steps S220 and S240), so that the increase in the torque and the fuel efficiency during cold operation are performed. Can be greatly improved.

(F) In step S280, the required ignition timing (a value obtained by adding the VVT correction amount (avvt) and the knock control amount (aknk) to the basic ignition timing (abse) set in step S260 or step S270. acal). Therefore, it is possible to control the ignition timing based on the optimum required ignition timing from considering VVT correction amount and the knock control amount.

(G) Required ignition timing (acal) and FIG.
Of the various control amounts shown as an example in step S290, the most retarded value is set as the final ignition timing.
It is possible to set an optimal ignition timing that satisfies these requirements even for a retard request or the like according to each operation state.

Although the embodiment of the present invention has been described above, the above embodiment can be implemented by changing its configuration as described below. In the above embodiment, the ignition timing control device according to the present invention is applied to a port injection type internal combustion engine, but the present invention is also applicable to a direct injection type internal combustion engine.

In the above embodiment, the MBT basic map value and the knock basic map value are corrected with both the dedicated water temperature correction value and the intake air temperature correction value, respectively. The correction may be made in one of the intake air temperature correction terms.

In the above-described embodiment, in addition to correcting the MBT basic map value and the knock basic map value by a dedicated water temperature correction value and / or an intake air temperature correction value, various types of knocking change can be performed. It is also possible to configure so that each correction is made according to factors or environmental conditions. Such a configuration is possible because the knock basic map shown in FIG. 2B is independent of the MBT basic map shown in FIG. 2A. Such factors include, for example, different standards for gasoline octane number in different countries, different intake temperature conditions for measuring the basic knock ignition timing, and the like. With the above-described configuration, a plurality of maps, each of which is adapted to each of the basic knock maps, is made for each country, so that it is possible to easily cope with the correction of the ignition timing according to the factor.

[0064] - the one embodiment, the MBT basic map shown in FIG. 2 (b), but are put the value of the minute knock point as used knock limit ignition timing substantially synonymous as knocking basic map value In short, it is only necessary that the ignition timing at which no knock occurs which is actually a problem is entered as the basic map value.

In the above embodiment, the ignition timing control device is applied to a gasoline engine as an internal combustion engine. However, the ignition timing control device may be applied to an LPG engine.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ignition timing control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a map provided in the control device.

FIG. 3 is a flowchart showing a temperature correction term calculation routine executed by the control device.

FIG. 4 is a flowchart showing an ignition timing calculation routine executed by the control device.

FIG. 5 is a graph showing the relationship between the load of the engine and the amount of advance at constant rotation.

FIG. 6 is a graph showing a relationship between a water temperature and an advance amount.

FIG. 7 is a graph showing a relationship between an intake air temperature and an advance amount;

[Explanation of symbols]

11: engine as an internal combustion engine, 30: intake temperature sensor, 33: water temperature sensor, 34: knock sensor, 35: rotational speed sensor, 36: igniter, 38: spark plug,
40 ... Electronic control unit (ECU)

Claims (6)

[Claims] An ignition timing control device for an internal combustion engine for controlling an ignition timing according to an operation state of the internal combustion engine, wherein a basic MBT ignition timing which is an ignition timing at which a maximum output is output as a basic ignition timing according to the operation state. And a basic ignition timing calculating means for separately calculating a basic knock ignition timing which is a knock limit ignition timing; and a correction value for the basic MBT ignition timing and a correction for the basic knock ignition timing as correction values corresponding to the engine temperature. Ignition timing correction means for separately calculating the two ignition timings with the two correction values, and a final ignition timing based on the ignition timing on the retard side of the two ignition timings corrected with the two correction values. An ignition timing control device for an internal combustion engine, comprising: final ignition timing setting means for setting an ignition timing. 2. The basic ignition timing calculating means obtains the basic MBT ignition timing by referring to an MBT basic map according to the operating state, and calculates the basic knock ignition timing according to the operating state. The ignition timing control device for an internal combustion engine according to claim 1, wherein the ignition timing control device is determined with reference to a basic map. 3. The ignition timing correction means separately obtains a water temperature correction value for the basic MBT ignition timing and a water temperature correction value for the basic knock ignition timing according to the cooling water temperature, and calculates the water temperature correction value for both the basic knock ignition timing. 3. The basic MBT ignition timing and the basic knock ignition timing are respectively corrected.
3. The ignition timing control device for an internal combustion engine according to claim 1. 4. The ignition timing correction means separately obtains an intake temperature correction value for the basic MBT ignition timing and an intake temperature correction value for the basic knock ignition timing in accordance with the intake air temperature. 3. The ignition timing control device for an internal combustion engine according to claim 1, wherein the basic MBT ignition timing and the basic knock ignition timing are respectively corrected by values. Wherein said ignition timing correcting means in accordance with the coolant temperature, the basic MBT ignition with the timing and for the water temperature correction value for the basic knock ignition timing determined separately according to the intake air temperature, the basic The intake air temperature correction values for the MBT ignition timing and the basic knock ignition timing are obtained separately, and the basic MBT ignition timing and the basic knock ignition timing are respectively corrected by these correction values. 3. The ignition timing control device for an internal combustion engine according to 2. 6. The ignition of an internal combustion engine according to claim 1, wherein the ignition timing correction means corrects the basic knock ignition timing in accordance with a factor that changes knocking. Timing control device.