JP2621396B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to an ignition timing for an internal combustion engine that controls the ignition timing of an internal combustion engine suitable for a plurality of fuels having different octane numbers. It relates to a control device.

[Conventional technology]

Vehicle fuels currently on the market, such as gasoline, include high octane fuel (high octane fuel) and low octane fuel (regular fuel). It is known that the octane number of the fuel has a correlation with the knock resistance of the internal combustion engine, and the higher the octane number of the fuel, the less the occurrence of knocking. For this reason, the basic ignition advance suitable for high-octane fuel is on the more advanced side than the basic ignition advance suitable for regular fuel. Therefore, when the ignition timing is controlled with the basic ignition advance angle adapted to the high octane fuel using the Regula fuel, the ignition timing becomes excessively advanced, so that preignition and knocking occur frequently, and the engine performance is sufficiently exhibited. In the worst case, and in the worst case, damage to the engine.
Conversely, when using high octane fuel to control the ignition timing with a basic ignition advance angle adapted to low octane fuel, MBT (Minimum
Since the ignition timing is controlled in a region that is considerably retarded from (um Spark Advance for Best Torque), the output decreases and the performance of the internal combustion engine cannot be fully exhibited.

For this reason, in the related art, a table of a basic ignition advance that is suitable for high-octane fuel and a table of a basic ignition advance that are suitable for Regula fuel are determined in advance, and the octane number is determined based on the detection output of a knocking sensor that detects knocking. Automatic determination is performed, and the ignition timing is controlled by selecting a table of basic ignition advance according to the determined octane number. As described above, in the ignition timing control device that automatically determines the octane number and controls the ignition timing, the determination result determined in the previous operation is stored in the backup RAM until the octane number is determined to be time-consuming, and the engine is started. During the octane number judgment at the time, learning control is performed in which a table is selected based on the judgment result stored in the backup RAM to control the ignition timing (Japanese Patent Publication No. Sho 61-43536).

However, in the method in which the previous determination result is stored and used at the time of starting the engine, the ignition advance suitable for the high octane fuel is performed during the octane number determination at the time of starting the engine immediately after the fuel used is switched from the high octane fuel to the regular fuel by refueling. , The ignition timing is controlled, so that knocking may occur frequently. In addition, if the weather conditions change greatly between the time when the engine is stopped and the time when the engine is started, the knock limit point fluctuates. Knocking may occur frequently when traveling from (until the retard amount is updated).

Conventionally, in the high engine speed range during octane number determination, the ignition timing is controlled with a relatively retarded ignition timing for the Regula fuel (Japanese Patent Laid-Open No. 60-216067). In the idle or engine light load range, the ignition timing is controlled by the ignition timing on the advance or retard side (Japanese Patent Application Laid-Open No. 60-79168), and the octane number discrimination result is reset at the time of fuel supply or starting (Japanese Patent Application Laid-Open No. No. 104774).

In addition, knocking is less likely to occur when the humidity increases or the atmospheric pressure decreases during operation with the Regula fuel, so that the octane number automatic determination described above may erroneously determine that the fuel used is a high octane fuel. If the table of the basic ignition advance is switched based on the erroneous determination result, knocking frequently occurs and pre-ignition occurs.
When switching from a table of basic ignition advancing suitable for Regula fuel to a table of basic ignition advancing suitable for high octane fuel, switching is performed so that the ignition advancing gradually changes (Japanese Patent Application Laid-Open No. 60-222564). No.). Conversely, when switching from the high-octane fuel table to the regular fuel table, resetting of the correction retarding amount for retarding the ignition timing when knocking occurs to prevent excessive retarding is performed. (JP-A-60-104775)
No.).

[Problems to be solved by the invention]

However, in the above-mentioned conventional techniques, since the ignition timing is controlled only on the safe side, during the octane number determination, during start-up, and during running for a while after starting (until the retard amount and the learning value are updated). Is controlled by the ignition timing on the retard side, there is a problem that the engine performance when the used fuel is high-octane fuel cannot be sufficiently exhibited. Also, when high-octane fuel and reguilla fuel are mixed and used, hunting occurs in the determination result,
The conventional table switching method has a problem that switching cannot be performed smoothly. Also, since the case where the backup RAM is removed from the battery or the storage content of the backup RAM becomes abnormal is not considered, it is not possible to efficiently perform the ignition timing control during the octane number determination.
There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and performs ignition timing control in consideration of fuel which is likely to be used, avoids frequent occurrence of knocking, avoids pre-ignition, and exhibits engine performance. It is an object of the present invention to provide an ignition timing control device for an internal combustion engine, which makes it possible to smoothly switch the basic ignition advance angle.

[Means for solving the problem]

In order to achieve the above object, a first invention comprises a knocking detecting means A for detecting whether or not knocking has occurred, and an ignition timing when knocking has been detected, as shown in FIG. And a correction delay amount calculating means B for calculating a correction delay amount for advancing the ignition timing when the occurrence of knocking is not detected, and a correction delay amount based on the correction delay amount. A learning value calculating means C for calculating a learning value at which the retard amount becomes the maximum value; and an octane number for determining whether the fuel used is a high octane number fuel or a low octane number fuel according to the detection result of the knocking detecting means. Discriminating means D, storage means E for storing the discrimination result of the octane number discriminating means D, and high value if the discrimination result stored in the storage means E is high octane number fuel at or after starting. Ok The ignition timing is controlled using the basic ignition advance, the corrected retard amount, and the learning value for the high-value high-speed region that is corrected to the retard side for the low-value fuel, and the learning value is equal to or less than a predetermined value. And control means F for controlling the ignition timing by switching to the basic ignition advance for high octane fuel when the operating state enters the low load region.

Further, as shown in FIG. 1 (2), the second invention comprises a knocking detecting means A for detecting whether or not knocking has occurred, and a method for delaying the ignition timing when the occurrence of knocking has been detected and A correction retardation amount calculating means for calculating a correction retardation amount for advancing the ignition timing when occurrence of knocking is not detected; and, based on the magnitude of the correction retardation amount, a magnitude of the correction retardation amount. Learning value calculating means C for calculating a learning value that reaches a maximum value; and octane number determining means D for determining whether the fuel used is a high octane fuel or a low octane fuel according to the detection result of the knocking detecting means. If it is determined that the fuel to be used is high octane fuel while controlling the ignition timing using the basic ignition advance for low octane fuel, the corrected retard amount, and the learned value, the operating state is For low load area Control means H for controlling the ignition timing by switching to a basic ignition advance for a high octane fuel and a high load high revolution region corrected to a retard side when the basic ignition advance is controlled by the control means H. Setting means G for setting a value corresponding to an advance difference between the basic ignition advance angle for high octane number fuel and the basic ignition advance angle for low octane number fuel as the learning value at the time of switching. .

And the third invention, as shown in FIG. 1 (3),
A knocking detecting means for detecting whether or not knocking has occurred, and a correction delay amount for retarding the ignition timing when the occurrence of knocking is detected and advancing the ignition timing when the occurrence of knocking is not detected. A correction retardation amount calculating means B, a learning value calculating means C for calculating a learning value having a maximum value of the correction retardation amount based on the magnitude of the correction retardation amount, and the knocking detection Octane number discriminating means D for discriminating whether the fuel to be used is a high octane number fuel or a low octane number fuel in accordance with the detection result of the means, and storage means E for storing the discrimination result of the octane number discriminating means.
When the contents stored in the storage means become abnormal, using the basic ignition advance for the high octane fuel and the high load and high rotation region corrected to the retard side, the corrected retard amount and the learning value. The control means J for controlling the ignition timing, and when the content stored in the storage means becomes abnormal, the learning value is used as a learning value, which is 1 / (1) of the advance angle difference between the basic ignition advance for the high octane fuel and the basic ignition for the low octane fuel. And setting means I for setting about two values.

[Action]

First, the operation of the first invention will be described with reference to FIG. Knocking detection means A detects whether or not knocking has occurred. The correction retardation amount calculating means B is based on the output of the knocking detection means A, and corrects the ignition timing when the occurrence of the knocking is detected and advances the ignition timing when the occurrence of the knocking is not detected. Is calculated. The learning value calculating means C includes a correction delay amount calculating means B.
The learning value is calculated based on the magnitude of the correction retardation amount calculated in. The learning value calculating means C calculates a learning value whose magnitude becomes the maximum value of the correction retardation amount. The octane number determination means D determines whether the fuel used is a high octane number fuel or a low octane number fuel. The determination of the octane number can be performed using the correction retardation amount in the correction retardation amount calculation means B determined according to the detection result of the knocking detection means. The storage unit E stores the result of the determination by the octane number determining unit D. When the determination result stored in the storage means E at the time of starting or after the starting is the high octane fuel, the control means F corrects the high load high revolution region for the high octane fuel to the retard side. The ignition timing is controlled by using the basic ignition advance angle, the corrected retard amount, and the learned value, and when the learned value is equal to or less than a predetermined value and the operation state enters a low load region, the basic ignition advance for high octane fuel is performed. The ignition timing is controlled by switching to the corner. That is, if the determination result stored in the storage means E at the start or after the start is a high octane fuel, the probability of erroneously refueling the low octane fuel when the vehicle is stopped is low. The advance angle is used as a reference. However, in consideration of the case where low octane number fuel is supplied, the ignition timing is controlled by retarding the high-load high-rotation region of the basic ignition advance for high octane number fuel, thereby avoiding pre-ignition and the like. Do.
When the learned value is equal to or less than the predetermined value and the operation state enters the low load region, the probability that the fuel used is high octane fuel is extremely high because the learned value is equal to or less than the predetermined value, and the operation state is low load. In this state, even if the ignition timing is switched to the advanced side, preignition does not occur. Therefore, the ignition timing is controlled by switching to the basic ignition advance for high octane number fuel.

Next, the operation of the second invention will be described with reference to FIG. The control means H of the second invention determines that the fuel to be used is a high octane fuel when the ignition timing is controlled using the basic ignition advance for the low octane fuel, the corrected retard amount, and the learning value. In this case, when the operating state enters the low load region, the ignition timing is controlled by switching to the basic ignition advance for high octane fuel and in the high load high rotation region corrected to the retard side. When the control means H switches the basic ignition advance, the setting means G sets a value corresponding to the advance difference between the basic ignition advance for high octane fuel and the basic ignition advance for low octane fuel as a learning value. I do. As a result, when the ignition timing is controlled by switching the basic ignition advance by the control means H, the value corresponding to the advance difference between the basic ignition advance for the high octane fuel and the basic ignition advance for the low octane fuel is obtained. The ignition timing is delayed by being reflected in the ignition timing. That is, if it is determined that the fuel to be used is a high octane fuel during operation using the basic ignition advance for low octane fuel, the fuel using a mixture of the low octane fuel and the high octane fuel is used or the Since it is possible that the fuel was temporarily determined to be a high octane fuel due to changes in conditions, etc., the result of the determination was tentatively correct, and the operating state entered a low load range and no knocking or pre-ignition occurred. Sometimes it is switched to the basic ignition advance for high octane fuel. At this time, since there is a possibility that only the high octane fuel is not used, the high-load high-rotation region of the basic ignition advance for the high octane fuel is retarded to avoid pre-ignition, etc. The ignition timing is controlled so that an amount corresponding to the advance difference between the basic ignition advance for fuel and the basic ignition advance for low octane fuel is retarded from the basic ignition advance. When switching from the basic ignition advance for low octane fuel to the basic ignition advance for high octane fuel, the engine performance suddenly rises, significantly lower than the prediction that had previously been made with accelerator control using the basic ignition advance for low octane fuel. Will change. However, even if the switching is performed as described above, the engine performance is not changed even if it is determined that the fuel is a high octane fuel and is switched from the basic ignition advance for the low octane fuel to the basic ignition for the high octane fuel. Also does not change drastically.

Finally, the operation of the third invention will be described with reference to FIG. The control means J according to the third invention, when the storage contents of the storage means E become abnormal, the basic ignition advance angle and the correction retardation for the high octane fuel and the high load and high revolution region corrected to the retard side. The ignition timing is controlled using the amount and the learning value. The learning value is set by the setting means I to a value that is about half the advance angle difference between the basic ignition advance angle for high octane fuel and the basic ignition advance angle for low octane fuel. As described above, the basic ignition advance is used as the basic ignition advance for the high octane fuel and for the high-load, high-speed region in which the high-load high-speed region is corrected to the retard side. 1/2 of the lead angle difference from the basic ignition lead angle for low octane fuel
Because the ignition timing is controlled by the retarded value, the memory content is abnormal, so it is not possible to determine whether the fuel is a high octane fuel or a low octane fuel, and the probability of using each fuel is 1/2. In this case, the ignition timing can be controlled with an ignition advance that is approximately intermediate between the basic ignition advance for the high octane fuel and the basic ignition for the low octane fuel.

〔The invention's effect〕

As described above, according to the first aspect of the present invention, at the time of starting or after starting, if the determination result stored in the storage means is high octane fuel, high load is applied based on the basic ignition advance angle for high octane fuel. Since the high revolution region is controlled with the retarded ignition timing, pre-ignition can be avoided even when low octane fuel is supplied by mistake, and when it is determined that the fuel is high octane fuel reliably. Since the basic ignition advance is switched, an effect is obtained that hunting can be prevented.

According to the second aspect of the present invention, when it is determined that the fuel to be used is a high octane number fuel during the operation at the ignition timing suitable for the low octane number fuel, the operation state is such that preignition does not occur. The basic ignition retard for high octane fuel is switched to the basic ignition retard for high octane fuel in which the high-load, high-speed region is corrected to the retard side, and the learned value is the advance difference between the basic ignition advance for high octane fuel and the basic ignition advance for low octane fuel. Hunting may occur if fuels with different octane numbers are used in a mixture or if the fuel used is determined to be a high octane fuel due to changes in weather conditions, etc. The effect is obtained that the ignition advance can be switched smoothly without causing the ignition. In addition, when high octane fuel is used, the ignition timing changes smoothly even when it is determined from low octane fuel to high octane fuel, and it gradually changes to the ignition timing for high octane fuel. You can gradually get used to it.

Further, according to the third aspect, when the stored content becomes abnormal, the basic ignition advance angle for the high octane fuel is used as the basic ignition advance angle and the high-load high-rotation side is corrected to the retard side. Since the ignition timing is controlled by the ignition advance between the basic ignition advance for the high octane fuel and the basic ignition advance for the low octane fuel, it is possible to avoid knocking and pre-ignition and to improve engine performance. It is possible to obtain an effect that it is possible to achieve compatibility with the performance.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 schematically shows an internal combustion engine (engine) provided with an ignition timing control device to which the first to third inventions are applied.

This engine is controlled by an electronic control circuit 44 such as a micro computer.
Downstream of the air flow meter 4 for detecting the intake air amount Q
Is disposed, and a throttle valve 8 is disposed downstream of the air flow meter 4. The throttle valve 8 is provided with an idle switch 10 that is turned on only when the throttle valve is fully closed. On the downstream side of the throttle valve 8, the sparger 6 and the surge tank 12 are arranged in this order. A surge tank bypassing the spur gear 6 and the throttle valve 8 and upstream of the throttle valve and downstream of the throttle valve.
A bypass passage is provided to communicate with the bypass passage. An ISC (idle speed control) valve 16B whose opening is adjusted by a pulse motor 16A having a four-pole stator is attached to the bypass passage 14, for example. The surge tank 12 is connected to a combustion chamber of the engine 20 via an intake manifold 18 and an intake port 22. A fuel injection valve 24 is attached to each cylinder so as to protrude into the intake manifold 18. Reference numeral 21 denotes an air bypass valve for controlling the amount of air flowing around the supercharger 6 to control the supercharging pressure.

The combustion chamber of the engine 20 is connected via an exhaust port 26 and an exhaust manifold 28 to a catalyst device 27 filled with a three-way catalyst. This exhaust manifold 28 outputs O ₂ which outputs a signal inverted with respect to the stoichiometric air-fuel ratio.
A sensor 30 is mounted. A knocking sensor 33 composed of a magnetostrictive element or the like for detecting engine vibration is attached to the cylinder block 32.
Is output to the control circuit 44, and the peak value of the signal in the frequency band (6 to 8 kHz) specific to the knocking is compared with the determination level determined from the background level of the output of the knocking sensor 33 to determine the knocking. An occurrence is detected. A cooling water temperature sensor 34 is provided in a cooling water passage communicating with the engine block. The cooling water temperature sensor 34 detects the engine cooling water temperature and outputs a water temperature signal to the control circuit 44.

An ignition plug 38 is attached to each cylinder so as to penetrate the cylinder head of the engine 20 and protrude into the combustion chamber. The ignition plug 38 is connected to a control circuit 44 via an ignition coil 40 and an igniter 42 having a distribution function. Further, a cam position sensor 48 for detecting a cam position is mounted so as to correspond to an end face of the cam shaft arranged on the cylinder head. The cam position sensor 48 outputs an engine rotation speed signal composed of a pulse train generated every 30 CA, for example.

The electronic control circuit 44 includes a micro processing unit (MPU), a read only memory (ROM), a random
Access memory (RAM), back-up plum (BU-RA)
M) and a bus such as a data bus and a control bus for connecting them.

The ROM contains the basic ignition advance (basic ignition advance for high-octane fuel) ABSE suitable for high-octane fuel shown in Fig. 3 (1).
Table of IH, table of the Regula correction amount ABSEIL shown in FIG. 3 (2) for compensating the basic ignition advance for the high-octane fuel and calculating the basic ignition advance suitable for the Regula fuel, high load and high rotation range The table of the high-load high-speed retardation amount shown in FIG. 3 (3) for correcting the basic ignition advance angle to the retard side, and a control routine program described below are stored in advance.

First, a routine for calculating the effective ignition advance angle θ will be described with reference to FIG. In step 152, it is determined whether or not the engine load Q / N is equal to or more than a predetermined value (for example, 0.6 l / rev) to determine whether or not the knocking control region exists. If not, the basic ignition advance is performed in step 154. The ABSE is returned as the effective ignition advance angle θ (normally corrected by the engine cooling water temperature and the intake air temperature). The calculation of the basic ignition advance angle ABSE will be described below with reference to FIGS. 8 and 9. on the other hand,
If it is determined in step 152 that the knocking is in the knocking control area, it is determined in step 156 whether or not knocking has occurred by comparing the peak value of the frequency band unique to knocking with the determined level. If the peak value is larger than the determination level, it is determined that knocking has occurred, and in step 158, the correction delay amount AKCS is increased by a predetermined value (for example, 1 CA). On the other hand, when it is determined that the peak value is equal to or lower than the determination level, it is determined that knocking has not occurred, and it is determined in step 160 whether a predetermined number of ignitions (for example, 10 ignitions) or a predetermined time has elapsed,
If the predetermined number of ignitions has elapsed, in step 162, the correction retardation amount AKCS is reduced by a predetermined value (for example, 1 CA).

In the next step 164, based on the engine load Q / N and the engine speed N, it is determined to which region in the learning region the current operating state belongs. In this learning region, as shown in FIG. 5, the engine load Q / N is a predetermined value (for example, 0.6
/ rev) are divided into six regions in accordance with the engine speed N, and learning values AKG1, AKG2,..., AKG6 are respectively defined for each learning region. In the next step 166, it is determined whether or not the driving state has entered the learning area determined in step 164 for the first time. When it is determined that the driving state has entered for the first time, step 17 is performed.
In step 4, the learning value AKGi (i = 1,
A value obtained by subtracting a predetermined value (for example, 2 CA) from any one of 2,... 6 is compared with the correction value retard amount AKCS. The value obtained by subtracting the predetermined value from the learning value AKGi is the corrected retard amount AKCS
If it is larger, a value obtained by subtracting a predetermined value from the learning value KAGi in step 176 is used as the correction retardation amount AKCS, and the next step 17
At step 8, the corrected retard amount AKCS is stored as the learning value AKGi, and then the process proceeds to step 172. On the other hand, when the value obtained by subtracting the predetermined value from the learning value AKGi is equal to or smaller than the correction retardation amount AKCS, the process directly proceeds to step 178.

On the other hand, when it is determined in step 166 that the driving state is continuously operated in the learning region determined in step 164, the learning value AKGi of the corresponding learning region is compared with the corrected retardation amount AKCS in step 168. I do. If the correction delay amount AKCS is larger than the learning value AKGi, the process proceeds to step 172 after storing the correction retardation amount AKCS as the learning value AKGi in step 170, and the correction delay amount AKCS becomes equal to the learning value AKGi.
If it is less than i, the process proceeds to step 172. Step 17
In 2, the value obtained by subtracting the correction retardation AKCS from the basic ignition advance ABSE is set as the effective ignition advance θ.

The above-mentioned correction delay amount AKCS is increased when knocking occurs and is decreased when knocking does not occur, and a value obtained by subtracting a predetermined value from the learning value immediately after entering the learning region is set as an initial value. It changes as shown in FIG. In addition, since the learning value stored up to the previous time is compared with the correction retard amount as the learning value and the larger value is stored, the learning value is corrected when the vehicle is driven in the learning area. It becomes equal to the maximum value of the retard amount.

Next, an octane value determination routine that can be used in this embodiment will be described with reference to FIG. First, step 18
At 0, it is determined whether or not the ignition timing is controlled with the basic ignition advance angle suitable for high-octane fuel. When the control is performed with the basic ignition advance suitable for the high-octane fuel, the correction retard amount AKCS is set to a predetermined value (for example, 12 ° C) in step 182.
A) It is determined whether or not a frequent occurrence of notching is long by determining whether or not a predetermined time (for example, 2 sec) or more has elapsed. When the determination in step 182 is affirmative, it is determined that the ignition timing is controlled to the over-advance side in the ignition timing control with the basic ignition advance suitable for high-octane fuel because the time during which knocking frequently occurs is long. At step 184, a discrimination flag XSELM is set to indicate that the fuel used is a regu- lar fuel. This determination flag XSELM is stored in the backup RAM.

On the other hand, if it is determined in step 180 that the ignition timing is being controlled at the basic ignition advance suitable for the regular fuel, then in step 186 the corrected retard amount AKCS is less than a first predetermined value (for example, 1 CA). It is determined whether or not the correction delay amount AKCS is larger than the first predetermined value in step 190.
Is determined to exceed a predetermined value (for example, 5 CA). If the corrected retard amount AKCS is less than the first predetermined value, the count value m is incremented in step 188,
When the corrected retardation amount AKCS exceeds the second predetermined value, the count value m is decremented in step 192.
When the count value m is decremented, the count value is limited so as not to be a negative value. When the correction delay amount AKCS takes a value between the first predetermined value and the second predetermined value, the process proceeds to step 194 as it is. Here, the count value m is incremented when the correction retardation amount AKCS is extremely small (when it is less than the first predetermined value). Therefore, when the count value m is large, the occurrence of knocking is almost eliminated. It can be determined that the absence state continues, whereby it can be determined that the ignition timing is controlled to be more retarded than the engine required value. Accordingly, the basic ignition angle for Regiyura fuel by determining whether the count in step 194 value m exceeds the judgment value m ₀ determines whether they comply with the fuel currently in use. When m> m _0, a state in which almost no knocking occurs for a long time in spite of the fact that the ignition timing is controlled with the ignition timing suitable for the Regula fuel, and the ignition timing is set at the basic ignition advance suitable for the Regula fuel. In step 196, the determination flag XSELM is reset to indicate that the fuel used is high-octane fuel. At this time, the count value m is also reset.

Next, a routine for setting the initial value of the basic ignition advance angle at the start and immediately after the start will be described with reference to FIG.
First, in step 100, it is determined whether or not the storage contents stored in the backup RAM have become abnormal. It is possible to determine whether or not the storage contents stored in the backup RAM have become abnormal by performing a parity check or the like. If it is determined that the contents stored in the backup RAM are normal, it is determined in step 102 whether the octane number determination result (octane number determination flag XSELM) stored in the backup RAM is a regular fuel or a high octane fuel. I do. If it is determined that the fuel is a regular fuel, the discriminating flag XSELM is reset again in step 104, and in step 106 the current engine speed is determined using the table of the basic ignition advance for high-octane fuel and the table of the correction amount of the regular. Speed N
And a basic ignition advance ABSE corresponding to the engine load Q / N. At this time, the basic ignition advance angle ABSE is set to a value obtained by subtracting the regula correction amount ABSEIL from the high-octane fuel basic ignition advance angle ABSEIH. Then, in step 108, the effective ignition advance angle θ is calculated in accordance with the routine described with reference to FIG.

Therefore, if the discrimination result stored in the backup RAM is normal and the content is a regular fuel, the ignition timing is controlled at an ignition timing suitable for the regular fuel.

On the other hand, when it is determined in step 102 that the storage content of the backup RAM is high-octane fuel, the determination flag XSELM is reset again in step 112, and then
In step 114, the basic ignition advance ABSE is calculated from the table for the basic ignition advance for high-octane fuel and the table for the high-load high-speed retardation amount. At this time, the basic ignition advance angle ABSE is a value obtained by subtracting the high-load high-speed retard amount ABSEIM from the high-octane fuel basic ignition advance angle ABSEIH. Therefore, when the contents stored in the backup RAM are normal and the contents are high-octane fuel, the high load high rotation region is controlled by the ignition timing suitable for the high-octane fuel corrected to the retard side. Here, the reason why the high-load high-rotation side of the high-octane fuel basic ignition advance is retarded when the content of the back-up RAM is high-octane fuel at the time of starting and after starting is that regula-fuel is erroneously supplied. In consideration of safety when
This is because pre-ignition and the like do not occur in the high-load high-rotation region. It should be noted that knocking may occur in the medium load region when the reguilla fuel is supplied, but there is no practical problem since the control is performed to the retard side by the corrected retard amount.

When it is determined in step 100 that the stored contents of the backup RAM are abnormal, in step 110, the basic ignition advance suitable for high-octane fuel and the basic ignition advance suitable for regular fuel are advanced to all of the learned values AKG1 to AKG6. After setting a value of about 1/2 of the angle difference (for example, 5 CA), step 112, step 114, and step 108 are executed. Therefore, when the probability that the fuel used is high-octane fuel and the probability that the fuel is regula fuel is equal (2/1) due to an abnormality in the contents stored in the backup RAM, the high-load high-speed region is corrected to the retard side. The ignition timing is controlled by the basic ignition angle for high-octane fuel and the learning value set as described above. The ignition timing is controlled by the ignition advance between the ignition advance and the basic ignition advance suitable for high-octane fuel, and the ignition timing immediately adapted to the used fuel is immediately controlled by the correction retarding amount of the knocking control. Is controlled. In a high-load and high-speed range where preignition is likely to occur, the ignition timing is controlled at an ignition advance angle close to the basic ignition advance angle for the regular fuel.

Next, a switching routine of a table for calculating the basic ignition advance angle ABSE during operation will be described with reference to FIG. At step 120, it is determined whether or not the determination result has been switched from the regular fuel to the high octane fuel by determining whether or not the determination flag XSELM has been reset from the set state. If it is determined that the fuel used has been switched from the regular fuel to the high-octane fuel, the engine load Q / N is set to a predetermined value (for example, 0.6 in step 122).
/ rev). Engine load Q /
If N is equal to or greater than the predetermined value, the basic ignition is calculated by subtracting the reguilla correction amount ABSEIL from the high-octane fuel basic ignition advance ABSEIH in step 128 using the high-octane fuel basic ignition advance table and the regula correction amount table. Calculates the lead angle ABSE. That is, when it is determined that the fuel to be used is high octane fuel while controlling the ignition timing with the basic ignition advance for the regula fuel, when the regula fuel and the high oct fuel are mixed and used, or when the Regula fuel is used. Despite the use of the engine, it may be determined that it is a high octane fuel due to changes in weather conditions, etc., and the accuracy of the determination result is low, so the engine load Q / N exceeds a predetermined value (medium to high load range). In a state in which knocking or pre-ignition is likely to occur, the ignition timing is controlled by a basic ignition advance angle suitable for the regu- lar fuel without changing the table used. The difference between the ignition timings of the high-octane fuel and the reguillar fuel is larger at higher loads (Q / N is larger), that is, the torque difference is larger at higher loads. This prevents a torque shock from occurring due to abrupt switching.

On the other hand, when it is determined in step 122 that the engine load Q / N has become less than the predetermined value (low load range), in step 124, the learning values AKG1 to AKG6 are changed to the basic ignition advance and the regular fuel suitable for high-octane fuel. A value corresponding to the advance angle difference from the appropriate basic ignition advance angle (for example, 7.5 CA)
In step 126, the high-load high-rotation retardation amount ABSEIM is subtracted from the high-octane fuel basic ignition advance angle ABSEIH using the high-octane fuel basic ignition advance table and the high-load high-rotation retardation amount table. The value thus set is set as the basic ignition advance angle ABSE, and then the routine proceeds to step 108.

As described above, when the accuracy of the determination result that the fuel used is high-octane fuel is low, the high-load high-rotation region of the basic ignition advance for high-octane fuel is corrected to the retard side when the operating state enters the low-load region. The basic ignition advance is switched to the basic ignition advance, and a value corresponding to the difference between the basic ignition advance suitable for the high-octane fuel and the basic ignition advance suitable for the Regula fuel is set as the learning value. Immediately after entering, it is controlled by the value obtained by subtracting the advance angle from the basic ignition advance for high-octane fuel (corresponding to the basic ignition advance suitable for Regula fuel), and then corrected by the correction retard amount AKCS Therefore, the ignition timing is gradually switched, so that the table can be switched to the smooth without generating knocking, pre-ignition and the like. Further, torque due to switching of the ignition timing can be reduced.

If it is not determined in step 120 that the fuel used has been switched from the regular fuel to the high octane fuel,
At step 130, it is determined whether or not it has been determined that the fuel used has been switched from high-octane fuel to regular fuel.
When it is determined that the fuel is switched from the high-octane fuel to the regular fuel, a small value (for example, 3 CA) is applied to all of the learning values AKG1 to AKG6 in step 132 in order to prevent the basic ignition advance switching and the initial excessive retardation. After the setting, in step 134, a value obtained by subtracting the regula correction amount ABSEIL from the high octane fuel basic ignition advance ABSEIH using the high octane fuel basic ignition advance table and the regula correction amount table is used as the basic ignition advance ABSE and the basic ignition advance ABSE. I do. Setting a small value for all of the learning values in this way is a large learning value when using a high-octane fuel table using legible fuel, and using it as it is after switching the table would be excessive. This is because there is a risk of retardation. Therefore,
When switching from the basic ignition advance suitable for high-octane fuel or the temperature ignition advance suitable for high-octane fuel with the high-load high-rotation region corrected to the retard side to the ignition advance suitable for regular fuel, the learning value is used. A small value is set to prevent the occurrence of excessive retardation at the beginning of switching.

If it is determined in step 130 that the switching of the used fuel has not been determined, it is determined in step 136 whether or not the determination flag XSELM has been set, thereby determining whether or not the used fuel is the regular fuel.
When it is determined that the fuel used is Regilleura fuel,
Proceeding to step 134, the basic ignition advance angle ABSE suitable for the regu- lar fuel is calculated. On the other hand, when it is determined that the fuel to be used is high-octane fuel, in step 138, the values of the learning values AKG3 to AKG5 in the medium load range are set to predetermined values (for example, 5 ゜).
CA) to determine whether the occurrence of knocking is low. If the determination in step 138 is affirmative and the occurrence of knocking is determined to be low, it is determined in step 140 whether the engine load Q / N is less than a predetermined value (for example, 0.6 / rev) to determine whether the engine load Q / N is in the low load region. Determine whether or not. When it is determined that the load is in the low load range, the basic ignition advance angle ABSEH is determined in step 142 using the table of the basic ignition advance angle for high octane fuel ABSEIH.
Is calculated. Therefore, when it is determined that the fuel to be used is high-octane fuel, the use table indicates that the basic ignition advance for high-octane fuel is performed only in the low-load region where the fuel to be used is reliably determined to be high-octane fuel in Steps 136 and 138. Switch to the corner table. Therefore, it is possible to prevent hunting and the like of switching tables due to the determination result when the high-octane fuel and the regular fuel are mixed and used.

In the above description, the engine that controls the ignition timing based on the engine load Q / N and the engine rotation speed N has been described. However, the present invention is also applicable to an engine that controls the ignition timing based on the intake pipe absolute pressure PM and the engine rotation speed N. The present invention can be applied. Further, the routine of FIG. 4 may be executed only at the time of starting or only after starting.

[Brief description of the drawings]

FIGS. 1 (1), (2) and (3) are block diagrams corresponding to claims (1), (2) and (3), respectively.
FIG. 1 is a schematic view of an internal combustion engine provided with an ignition timing control device according to an embodiment of the present invention. FIG. 3 (1) is a diagram showing a table of a basic ignition advance angle for high-octane fuel, and FIG. FIG. 3 (3) is a diagram showing a table of a correction amount for correcting the basic ignition advance for high-octane fuel to the basic ignition advance for reguilla fuel, and FIG. FIG. 4 is a diagram showing a table of a retard amount for retarding an area, FIG.
FIG. 5 is a flowchart showing an ignition advance calculation routine, FIG. 5 is a diagram showing a learning region, FIG. 6 is a diagram showing a change in the correction retardation amount AKCS, FIG. 7 is a flowchart showing an octane number determination routine,
FIG. 8 is a flowchart showing a routine for setting an ignition timing table at the start and after the start, and FIG. 9 is a flowchart showing a routine for switching the table during operation. 33 ... knocking sensor, 42 ... igniter, 44 ... control circuit.

Claims (3)

(57) [Claims] 1. A knocking detecting means for detecting whether or not knocking has occurred, and a correction delay for delaying the ignition timing when the occurrence of knocking is detected and advancing the ignition timing when the occurrence of knocking is not detected. Correction retardation amount calculation means for calculating an angle amount; learning value calculation means for calculating a learning value having a maximum value of the correction retardation amount based on the magnitude of the correction retardation amount; Octane number discriminating means for discriminating whether the fuel to be used is a high octane number fuel or a low octane number fuel in accordance with the detection result of the knocking detecting means; storage means for storing the discrimination result of the octane number discriminating means; Alternatively, if the determination result stored in the storage means after starting is a high octane fuel, the basic point for the high octane fuel and the high load / high rotation region corrected to the retard side is used. The ignition timing is controlled using the advance angle, the corrected retard amount, and the learned value, and when the learned value is equal to or less than a predetermined value and the operating state enters a low load region, the basic ignition advance angle for a high octane fuel. Control means for controlling the ignition timing by switching the ignition timing to an ignition timing control device for an internal combustion engine. 2. A knocking detecting means for detecting whether or not knocking has occurred, and a correction delay for delaying the ignition timing when the occurrence of knocking is detected and advancing the ignition timing when the occurrence of knocking is not detected. Correction retardation amount calculation means for calculating an angle amount; learning value calculation means for calculating a learning value having a maximum value of the correction retardation amount based on the magnitude of the correction retardation amount; Octane number discriminating means for discriminating whether the fuel used is a high octane number fuel or a low octane number fuel in accordance with the detection result of the knocking detecting means; a basic ignition advance angle for the low octane number fuel, the correction retard amount, and the learning. If it is determined that the fuel to be used is a high octane fuel while controlling the ignition timing using the value, the fuel is used for the high octane fuel when the operating state enters a low load region. Control means for controlling the ignition timing by switching to a basic ignition advance in which the load rotation region is corrected to a retard side; and when the basic ignition advance is switched by the control means, a basic value for high octane fuel is used as the learning value. Setting means for setting a value corresponding to an advance difference between the ignition advance angle and the basic ignition advance angle for low octane fuel, comprising: an ignition timing control device for an internal combustion engine. 3. A knocking detecting means for detecting whether or not knocking has occurred, and a correction delay for delaying the ignition timing when the occurrence of knocking is detected and advancing the ignition timing when the occurrence of knocking is not detected. Correction retardation amount calculation means for calculating an angle amount; learning value calculation means for calculating a learning value having a maximum value of the correction retardation amount based on the magnitude of the correction retardation amount; Octane number discriminating means for discriminating whether the fuel used is a high octane number fuel or a low octane number fuel in accordance with the detection result of the knocking detecting means; storage means for storing the discrimination result of the octane number discriminating means; When the storage contents of the means become abnormal, the basic ignition advance, the corrected retardation amount and the learned value for a high octane number sample and in which the high-load high-speed region is corrected to the retard side are used. Control means for controlling the ignition timing; and, when the contents stored in the storage means become abnormal, the learning value is set to 1/2 of the advance difference between the basic ignition advance for the high octane fuel and the basic ignition for the low octane fuel. Setting means for setting a degree value; and an ignition timing control device for an internal combustion engine, comprising: