JP2022041511A - Ignition timing control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition timing control device for an internal combustion engine which suppresses the occurrence of knocking. SOLUTION: A basic operating area partitioned by operating conditions and a plurality of subdivided operating areas in which the basic operating areas are subdivided are set, and when the operating state is the basic operating area, the first learning value is updated and the operation is performed. When the state is in the subdivided operation region, the second learning value is updated, and the ignition timing command value is calculated based on the first learning value, the second learning value, and the basic ignition timing. Further, the subdivided operation area is allocated to the learning effective area or the learning invalid area, and when the operating state is the learning effective area, the second learning value is updated based on the presence or absence of knocking, and when the operating state is the learning invalid area. The second learning value is the average value of the second learning value in the subdivided driving region in the learning effective region, the second learning value on the most retarded side in the learning effective region, and the learning invalid region to which the driving state belongs. An ignition timing control device using any of the second learning values updated in the subdivided operation region in the learning effective region closest to the subdivided operation region. [Selection diagram] FIG. 4

Description

The present invention relates to an ignition timing control device for an internal combustion engine.

A plurality of basic operating regions partitioned based on the operating conditions of the internal combustion engine and a plurality of subdivided operating regions in which a part of the plurality of basic operating regions is subdivided are set, and the operating state is the plurality of basic operating regions. The first learning value is updated when it is in any of them, and the second learning value is updated when the operating state is in any of a plurality of subdivided driving regions. An ignition timing control device for an internal combustion engine that calculates an ignition timing command value based on the ignition timing is known. Further, when the second learning value is updated in a predetermined subdivided operation area, there is a method of reflecting the updated amount of the updated second learning value in the second learning value of the surrounding subdivided operation area. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-209886

In the above method, the second learning value in the subdivided operation region where the update frequency is high is reflected in the subdivided operation region where the update frequency of the second learning value is low. Therefore, when the operating state belongs to the subdivided operating region where the update frequency is low, the ignition timing controlled by the second learning value is set to the advance angle side beyond the knock limit, and knocking may occur. be.

Therefore, an object of the present invention is to provide an ignition timing control device for an internal combustion engine that suppresses the occurrence of knocking.

For the above purpose, a plurality of basic operating regions partitioned based on the operating conditions of the internal combustion engine and a plurality of subdivided operating regions in which a part of the plurality of basic operating regions is subdivided are set, and the operation of the internal combustion engine is performed. The first learning value is updated when the state is in any of the plurality of basic operating regions, and the second learning value is updated when the operating state is in any of the plurality of subdivided operating regions. In the ignition timing control device of an internal combustion engine that calculates the ignition timing command value based on the first learning value and the second learning value and the basic ignition timing, the plurality of subdivided operation regions are set as learning effective regions or learning invalid regions. The allocation, the learning effective region is a region where the operation frequency of the internal combustion engine is high, the learning invalid region is a region where the operation frequency of the internal combustion engine is lower than the learning effective region, and the operating state is the learning. When it belongs to the effective region, the second learning value is updated based on the presence or absence of knocking in the internal combustion engine, and when the operating state belongs to the learning invalid region, the second learning value is described as the second learning value. The average value of the second learning value updated for each subdivided operation region in the learning effective region, the second learning value on the most retarded side in the learning effective region, and the learning invalidity to which the operating state belongs. This can be achieved by an ignition timing control device for an internal combustion engine using any of the second learning values updated in the subdivided operating region in the learning effective region closest to the subdivided operating region of the region.

According to the present invention, it is possible to provide an ignition timing control device for an internal combustion engine that suppresses the occurrence of knocking.

FIG. 1 is a schematic diagram showing a schematic configuration of an internal combustion engine. FIG. 2 is a graph showing the procedure for calculating the ignition timing command value. FIG. 3 is a graph showing an example of a basic learning area and a subdivided operation area on the operation area. 4A to 4C are explanatory views of a subdivided operation region. FIG. 5 is a flowchart showing an example of control for dividing a plurality of subdivided operation regions executed by the ECU into a learning effective region and a learning invalid region. FIG. 6 is a flowchart showing an example of calculation of the ignition timing command value executed by the ECU.

FIG. 1 is a schematic diagram showing a schematic configuration of an internal combustion engine 10. As shown in FIG. 1, air is sucked into the combustion chamber 11 of the internal combustion engine 10 through the intake passage 12, and fuel injected from the fuel injection valve 13 is supplied. When the spark plug 14 ignites the air-fuel mixture composed of the intake air and the injected fuel, the air-fuel mixture burns, the piston 15 reciprocates, and the crankshaft 16 of the internal combustion engine 10 rotates. The air-fuel mixture after combustion is sent out from the combustion chamber 11 of the internal combustion engine 10 to the exhaust passage 17 as exhaust gas.

The ECU (Electronic Control Unit) 30 executes various controls for operating the internal combustion engine 10. The ECU 30 is a central processing unit that executes various arithmetic processes related to various controls, a non-volatile memory in which programs and data necessary for the arithmetic are stored, and a volatile memory in which the arithmetic results of the central processing unit are temporarily stored. It is equipped with a volatile memory, an input port and an output port for inputting and outputting signals to and from the outside.

Various sensors are connected to the input port of the ECU 30. Examples of such sensors include an accelerator sensor 31 that detects the amount of depression of the accelerator pedal 18 (hereinafter, “accelerator depression amount AC”) and an opening degree of a throttle valve 19 provided in the intake passage 12 (hereinafter, “throttle”). A throttle sensor 32 for detecting the opening degree TA) and a knock sensor 33 for detecting the occurrence of knocking in the internal combustion engine 10 are provided. In addition, the air amount sensor 34 that detects the amount of air passing through the intake passage 12 (hereinafter, "passage air amount GA"), the rotation speed of the crankshaft 16 (hereinafter, "engine rotation speed NE"), and the rotation angle are detected. The crank sensor 35 and the ignition switch 36 operated at the start and stop of the operation of the internal combustion engine 10 are also provided.

The ECU 30 grasps the operating state such as the engine rotation speed NE and the engine load KL based on the output signals of various sensors. The engine load KL is calculated based on the intake air amount obtained based on the accelerator depression amount AC, the throttle opening TA, and the passage intake amount GA, and the engine rotation speed NE. The ECU 30 outputs a command signal to various drive circuits connected to the output port according to the operating state thus grasped. The controls performed by the ECU 30 in this way include throttle control for adjusting the opening degree of the throttle valve 19, fuel injection control for adjusting the injection amount of the fuel injection valve 13, and ignition timing for adjusting the ignition timing of the spark plug 14. Control is mentioned. The ECU 30 is an example of an ignition timing control device for an internal combustion engine.

The ECU 30 maintains the power supply to the non-volatile memory and retains the stored value even after the ignition switch 36 is operated to stop the operation of the internal combustion engine 10.

Ignition timing control will be described. FIG. 2 is a graph showing the procedure for calculating the ignition timing command value. In the ignition timing control, the ignition timing command value (hereinafter, “ignition timing command value ST”) to be transmitted to the spark plug 14 is calculated based on the operating state. The ignition timing of the spark plug 14 is advanced as the ignition timing command value ST increases.

As shown in FIG. 2, the basic ignition timing shown by the solid line L1 (hereinafter referred to as “basic ignition timing BT”) is a value corresponding to the ignition timing on the most advanced side that does not cause knocking under standard environmental conditions. Yes, it is calculated based on the engine load KL and the engine rotation speed NE. Specifically, the basic ignition timing BT is the first ignition timing on the advance side in the range of the MBT ignition timing at which the torque is most generated and the ignition timing at which knocking does not occur under the environmental conditions where knocking is least likely to occur. Of the knock limit ignition timing, the value on the retard side is selected and set.

The second knock limit ignition timing (hereinafter referred to as “second knock limit ignition timing BK2”) indicated by the broken line L2 is the most advanced side in the range of the ignition timing that does not cause knocking under the environmental conditions where knocking is most likely to occur. It is a value indicating the ignition timing of. Examples of the environmental conditions include air temperature, humidity, atmospheric pressure, engine cooling water temperature, and the like, and the susceptibility to knocking in the internal combustion engine 10 changes according to these conditions. Then, as the second knock limit ignition timing BK2, a value obtained by subtracting the knock margin R from the basic ignition timing BT, that is, a value retarded by the knock margin R from the basic ignition timing BT is calculated. Further, the knock margin R is a fixed value predetermined by an experiment or the like. Here, in the present embodiment, the second knock limit ignition timing BK2 functions as a basic value.

When it is determined that knocking has occurred based on the output signal of the knock sensor 33, the feedback correction term F is reduced by a predetermined retard angle update amount a to retard the ignition timing command value ST. On the other hand, when it is determined that knocking has not occurred, the amount is increased by a predetermined advance angle update amount b to advance the ignition timing command value ST. According to this feedback correction term F, when knocking occurs, the ignition timing command value ST is immediately retarded to suppress the occurrence, while when knocking does not occur, the ignition timing command value ST is advanced. The engine output is increased.

The ignition timing learning value AGT is a value obtained from the following relational expression (1) based on the first learning value AG which is the first learning value and the second learning value AGdp which is the second learning value.
AGT = AG + AGdp ... (1)
Here, the first learning value AG is a new first learning value corresponding to each of the basic learning areas A1 to A3 in which the value obtained by subjecting the feedback correction term F to the gradual change processing is determined by the engine rotation speed NE at that time. It is stored as AG. By such a first learning value AG, the ignition timing command value ST is constantly corrected in order to suppress the occurrence of knocking. Further, in the above-mentioned deflection processing, for example, assuming that the first learning value AG updated in the immediately preceding calculation cycle is the "previous learning value" and a positive number of 1.0 or more is "n", the relational expression [AG = {"Previous learning value" × (n-1) + “Feedback correction term F”} / n] to calculate the first learning value AG.

Then, the value corresponding to the subdivided operation region n including the operation state at that time is updated based on the feedback correction term F in the second learning value AGdp. The update of the second learning value AGdp basically stores the value obtained by subjecting the feedback correction term F to the feedback correction term F as a new second learning value AGdp in the same manner as the update of the first learning value AG. And so on.

The ignition timing command value ST is corrected by the feedback correction term F and the ignition timing learning value AGT, which increases or decreases depending on the presence or absence of knocking with respect to the second knock limit ignition timing BK2, which is basically calculated based on the operating condition. It is calculated by adding the correction by. That is, the ignition timing command value ST is obtained from the following relational expression (2) based on the second knock limit ignition timing BK2, the feedback correction term F, and the ignition timing learning value AGT.

ST = BK2 + F + AGT ... (2)
As described above, the ignition timing command value ST is calculated by adding the correction by the ignition timing learning value AGT to the second knock limit ignition timing BK2, and is usually calculated from the second knock limit ignition timing BK2. Is also a value corresponding to the timing on the advance side. In this state, when the feedback correction item F is increased or decreased depending on the presence or absence of knocking, the ignition timing command value ST is indicated by the arrow Y1 or the arrow Y2 in the figure by the increase or decrease of the feedback correction item F. Increase or decrease. Then, the ignition timing learning value AGT is updated by storing the value obtained by subjecting the feedback correction term F, which increases or decreases in this way, as a new ignition timing learning value AGT in the non-volatile memory of the ECU 30.

Next, the first learning value AG and the second learning value AGdp will be described in detail. FIG. 3 is a graph showing an example of the basic learning areas A1 to A3 and the subdivided operation area n on the operation area. As shown in FIG. 3, a plurality of basic learning areas A1 to A3, which are a plurality of basic operation areas partitioned according to the engine rotation speed NE, are set. The first learning value AG is prepared in the basic learning areas A1 to A3. This first learning value AG is stored as a new first learning value AG in which the value obtained by subjecting the feedback correction term F to the gradual change processing corresponds to the basic learning areas A1 to A3 determined by the engine rotation speed NE at that time. To. Each first learning value AG is stored in the non-volatile memory of the ECU 30.

However, the influence of the deposit in the combustion chamber 11 on the occurrence of knocking may be significantly different for each finer operating region even within the same basic learning region A1. Therefore, depending on the operating state in the basic learning area A1, the first learning value AG may be an inappropriate value for suppressing the occurrence of knocking due to the deposit in the combustion chamber 11. Specifically, there is a possibility that the first learning value AG becomes too large in order to suppress the occurrence of knocking, and the occurrence of knocking cannot be effectively suppressed.

Therefore, in the basic learning area A1 which is a region in the basic learning regions A1 to A3 in which the degree of influence of knocking due to the deposit in the combustion chamber 11 varies greatly, a plurality of subdivided operations finer than the basic learning region A1 are performed. A plurality of subdivided operation regions n, which are regions, are set.

When the operating state belongs to the basic learning areas A1 to A3 other than the subdivided operating area n, "0" is set as the second learning value AGdp. That is, the ignition timing command value ST is calculated without using the second learning value AGdp.

The second learning value AGdp will be described in detail with reference to FIGS. 4A to 4C. 4A to 4C are explanatory views of the subdivided operation region n. As shown in FIG. 4A, a plurality of subdivided operation regions n are set in the operation region with the engine rotation speed NE and the engine load KL as the coordinate axes. The entire subdivided operation region n is formed by being surrounded by a pair of sides parallel to the coordinate axis of the engine rotation speed NE and a pair of sides parallel to the coordinate axis of the engine load KL. The subdivided operation region n is partitioned by a side parallel to the coordinate axis of the engine rotation speed NE and a side parallel to the coordinate axis of the engine load KL, and a plurality of multipoint learning regions are formed. .. Specifically, it is divided into eight in the direction of change of the engine load KL and eight in the direction of change of the engine rotation speed NE, so that a total of 64 subdivided operation regions n [n]. = 1 to 64] is set.

Then, as shown in FIGS. 4B and 4C, the plurality of subdivided operating regions n are divided into a learning effective region R1 and a learning ineffective region R2 according to the operating state. The learning effective region R1 and the learning invalid region R2 will be described in detail later, but the learning effective region R1 is set in the region where the driving frequency is high, and the learning invalid region R2 is set in the other low regions. Further, when the operating state at that time is in the subdivided operating region n in the learning effective region R1, the second learning value AGdp is updated. On the other hand, when the operating state is in the subdivided operating region n in the learning invalid region R2, the average value of the second learning value AGdp in the subdivided operating region n in the learning effective region R1 is used as the learning invalid region. It is used as the second learning value AGdp in R2.

FIG. 5 is a flowchart showing an example of control for partitioning a plurality of subdivided operation regions n executed by the ECU 30 into a learning effective region R1 and a learning invalid region R2. First, the ECU 30 acquires the subdivided operation region n to which the operation state belongs (step S1). Next, the ECU 30 determines whether or not the acquired subdivided operation region n is the learning invalid region R2 (step S2). Here, as shown in FIG. 4A, initially, all of the subdivided operation regions n are learning invalid regions R2. If No in step S2, this control ends. In the case of Yes in step S2, the ECU 30 starts measuring the staying time in the acquired subdivided operation region n (step S3). Next, the ECU 30 determines whether or not the staying time has elapsed for a predetermined time or more (step S4). If No in step S4, this control ends. In the case of Yes in step S4, the ECU 30 sets the acquired subdivided operation region n as the learning effective region R1 (step S5).

By the above control, all the subdivided operation regions n are initially the learning invalid region R2 as shown in FIG. 4A, but as the operation is continued, the learning effective region R1 is expanded as shown in FIGS. 4B and 4C. .. Therefore, the difference in the driving characteristics of the driver and the operating characteristics depending on the vehicle type is reflected in the learning effective region R1 and the learning invalid region R2.

The staying time is cumulatively measured. For example, the operating state shifts to another subdivided operation region 2 [n = 2] before the period of stay in the subdivided operation region 1 [n = 1] reaches the predetermined time in step S4, and then subdivision is performed again. When shifting to the operation area 1, the measurement is performed from the previous measurement time in the subdivided operation area 1. However, the measurement time is reset every predetermined number of trips or every predetermined mileage.

Next, the calculation of the ignition timing command value ST in the subdivided operation region n will be described. FIG. 6 is a flowchart showing an example of calculation of the ignition timing command value ST executed by the ECU 30. The ECU 30 determines whether or not the operating state belongs to the learning effective region R1 (step S11). In the case of Yes in step S11, the ECU 30 updates and uses the second learning value AGdp (step S12). If No in step S11, that is, if the operating state belongs to the learning invalid region R2, the ECU 30 has all the subdivided operating regions in the learning effective region R1 in order to calculate the ignition timing command value ST. The average value of the second learning value AGdp in n is used as the second learning value AGdp of the learning invalid region R2 (step S13).

Here, for example, it is assumed that the second learning value AGdp is updated even in the subdivided operation region n in the learning invalid region R2 where the operation frequency is low. If the second learning value AGdp is updated and used to set the ignition timing even in the subdivided operation region n where the operation frequency is low, the operation frequency is low and the update frequency is low. Even if the knocking resistance is reduced due to the accumulation of deposits in the above, the ignition timing is set to the advance side beyond the knocking limit because the update frequency of the second learning value AGdp is low. , Knocking may occur.

In this embodiment, when the operating state belongs to the learning invalid region R2 as described above, the ignition timing is used by using the average value of the second learning value AGdp in the subdivided operating region n in the learning effective region R1. Therefore, even if the knocking resistance is lowered due to the above-mentioned cause, the deterioration of this knocking is reflected in the ignition timing when the operating state belongs to the learning invalid region R2. Therefore, the occurrence of knocking is suppressed.

In the above embodiment, when the operating state belongs to the learning invalid region R2, the average value of the second learning value AGdp in the subdivided operating region n in the learning effective region R1 is used, but the present invention is limited to this. For example, the minimum value of the second learning value AGdp in the plurality of subdivided operation regions n in the learning effective region R1, that is, the second learning value in the plurality of subdivided operation regions n in the learning effective region R1. The second learning value AGdp set on the most retarded side of the AGdp may be used. Further, when the operating state belongs to the learning invalid region R2, it is updated in the subdivided operating region n in the learning effective region R1 which is the closest to the subdivided operating region n in the learning invalid region R2 to which the operating state belongs. The second learning value AGdp may be used. When there are two or more subdivided operation regions n in the nearest learning effective region R1, the second learning value AGdp updated in any of the subdivided operation regions n is used. Even with such a configuration, even if the knocking resistance due to the above-mentioned causes is lowered, the occurrence of knocking can be suppressed.

When the driving state belongs to the learning invalid region R2, the average value of the second learning value AGdp in all the subdivided driving regions n in the learning effective region R1 is used. For example, the learning effective region is used. Not the average value of the second learning value AGdp in all the subdivided operation regions n in R1, but two or more in the learning effective region R1 close to the subdivided operation region n in the learning invalid region R2 to which the operating state belongs. The average value of the second learning value AGdp in the subdivided operation region n of the above may be used. For example, the average value of the second learning values AGdp in the four subdivided operating regions n in the learning effective region R1 closest to the subdivided operating region n in the learning invalid region R2 to which the operating state belongs may be used. ..

Further, the ignition timing control device for an internal combustion engine according to the above embodiment has been described as an example applied to an internal combustion engine for a vehicle, but can be applied as long as an internal combustion engine is used as a power source, for example, a so-called hybrid. It can be applied not only to an internal combustion engine mounted on a car or a motorcycle, but also to an internal combustion engine mounted on something other than a vehicle such as a ship or a construction machine.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 ... Internal combustion engine, 11 ... Combustion chamber, 12 ... Intake passage, 13 ... Fuel injection valve, 14 ... Ignition plug, 15 ... Piston, 16 ... Crankshaft, 17 ... Exhaust passage, 18 ... Accelerator pedal, 19 ... Throttle valve, 30 ... ECU (ignition timing control device for internal combustion engine), 31 ... accelerator sensor, 32 ... throttle sensor, 33 ... knock sensor, 34 ... air volume sensor, 35 ... crank sensor, 36 ... ignition switch.

Claims (1)

A plurality of basic operating regions partitioned based on the operating conditions of the internal combustion engine and a plurality of subdivided operating regions in which a part of the plurality of basic operating regions is subdivided are set, and the operating states of the internal combustion engine are the plurality. The first learning value is updated when it is in any of the basic operating regions of the above, and the second learning value is updated when the operating state is in any of the plurality of subdivided operating regions. And in the ignition timing control device of the internal combustion engine that calculates the ignition timing command value based on the second learning value and the basic ignition timing.
The plurality of subdivided operation areas are allocated to the learning effective area or the learning invalid area, and the learning effective area or the learning invalid area is allocated.
The learning effective region is a region where the internal combustion engine is operated frequently.
The learning ineffective region is a region in which the operating frequency of the internal combustion engine is lower than the learning effective region.
When the operating state belongs to the learning effective region, the second learning value is updated based on the presence or absence of knocking in the internal combustion engine.
When the operating state belongs to the learning invalid region, the second learning value is an average value of the second learning values updated for each subdivided operating region in the learning effective region, and the learning effective. The second learning value on the most retarded side in the region, and the second learning value updated in the subdivided operation region in the learning effective region closest to the subdivided operation region of the learning ineffective region to which the operation state belongs. An ignition timing control device for an internal combustion engine using any of the two learning values.

Images