JPS6375355A - Knocking control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of knocking even under a running state in that a fluctuation factor is high, by providing a knocking control means, a leaning means, and a clocking means, measuring an elapse time in which an engine is escaped from a high load state in that the knocking control means is actuated. CONSTITUTION:When a running state enters a range. of the number of revolutions of an engine and a load in a knocking control region, an electronic control circuit 20 determines a delay angle decrease amount during ignition, stored in an ROM 31, according to contents of a counter of an elapse time being outside a control region. Namely, a delay angle decrease amount is increased in proportion to the increase in an elapse time, and in the case of 3 sec or more, it is approximately [2 deg.CA]. A stored and learned delay angle correction amount required for prevention of the occurrence of knocking is searched, by deducting the delay angle decrease amount from the delay angle correction amount, an ignition timing is delayed, and feedback control is made so that a detecting signal from a knocking sensor 9 is reduced to a given value or less. Namely, the more a period in which an engine is escaped from a control region is decreased, the more a delay angle correction amount is increased, an increase of a delay angle amount is rapidly executed, a transient knocking is prevented from occurring.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a knocking control device that suppresses knocking occurring in an internal combustion engine, and in particular, to learning control of the ignition timing retard m to achieve highly responsive control. The present invention relates to a knocking 1 control device for an internal combustion engine that can realize the following.

[Prior Art] Conventionally, the following knocking control is well known as an ignition timing control for suppressing knocking that occurs in an internal combustion engine. In addition to calculating the ignition timing θB that is considered to be optimal for the internal combustion engine from the operating state of the internal combustion engine, when the internal combustion engine is in a high load state of load ON1 or higher, the knocking that occurs is actually measured. The retardation correction ff1OK is gradually increased so that knocking is below a predetermined level, and the actual ignition timing θ is determined by the following equation.

θ = θB - θK (Load QN1 or more) Furthermore, although knocking can be suppressed with the above control, there is a long transient period in which the retardation correction amount θK gradually increases, and continuous knocking during that period becomes a problem. . Therefore, the following learning control is usually adopted.

This is because the operating state of the internal combustion engine is displayed two-dimensionally using the rotation speed NE [rpm] and the load Q/N [Q/rev] as parameters, as shown in Figure 2, and the inside is first divided into certain regions. be. In FIG. 2, areas A and B are taken as an example.

C is set. These regions are the regions where the knocking control is executed (load QN1 or more), and one learning value GA, G is set for each region.
B, GC is determined as follows. When the operating state of the internal combustion engine is in one of regions A, B, or C,
The maximum value θl (m of the retardation correction amount θ) determined by the above-mentioned knocking control during driving from entering the region to leaving the region
Alternatively, it is stored as GC. Then, when the operating state of the internal combustion engine that has left this region enters the same region again, the learning stored as described above is used as the first value (initial value) for the retardation correction amount θ due to the knocking control. The value obtained by subtracting a constant value, for example, 2° [CA] from the
Km-2), and from then on, the value of the retardation correction amount OK is controlled while monitoring the knocking situation of the internal combustion engine, and the maximum value at that time θ) (m is learned for the next process. It will be done.

According to the knocking control device that employs learning control as described above, a value that is estimated to be the most appropriate value for the retardation correction amount θ within a certain high-load driving range is learned in advance, and the As soon as the state enters that region, the learned value is reflected in the retard angle correction amount, so that highly responsive knocking control can be achieved.

[Problems to be Solved by the Invention] However, even the knocking control device employing the learning control described above is still not sufficient and has the following problems.

The load on an internal combustion engine has an extremely large fluctuation rate and exhibits various changes. For example, the load on an internal combustion engine for a vehicle when driving on a mountain road or uphill road changes frequently within a short period of time, from a high load state that requires knock control to a low load state that does not require knock control. It turns out. In such a case, if the load on the internal combustion engine is taken as a long-term average, it is a high load state, which causes an increase in the intake air temperature, and can be said to be an operating state where knocking is likely to occur.

However, according to the conventional knocking control device, when the knocking control device operates for a short time, there is no time to increase the retardation correction amount θK to the optimum value while detecting the knocking occurring in the internal combustion engine. Therefore, the internal combustion engine is operated with an insufficient retardation correction amount OKe that slightly causes knocking. Furthermore, when the above-mentioned high load condition occurs again, the initial value of the retard angle correction amount θ is set to the above-mentioned insufficient retard angle correction amount θ).
(A smaller value obtained by further subtracting 2° [CA] from e will be set, and knocking in the internal combustion engine will occur transiently with a size that cannot be ignored.

The present invention has been made in view of the above-mentioned problems, and it is possible to control the ignition timing with an accurate amount of retardation no matter how large the fluctuation rate of the load on the internal combustion engine is, thereby suppressing knocking of the internal combustion engine while providing the best possible control. The purpose of this invention is to provide an excellent knocking control device for an internal combustion engine that can bring out the best power performance of the engine.

[Means for solving the problems] The means configured by the present invention to solve the above problems are as follows:
As illustrated in the basic configuration diagram of Fig. 1, the internal combustion engine EG
from the basic ignition timing determined by the operating condition of the internal combustion engine EG and the retardation correction amount determined to reduce knocking occurring in the internal combustion engine to a predetermined level or less when the load becomes higher than a predetermined operating condition. knocking control means C1 for determining the ignition timing of the internal combustion engine; firming means C2 for learning the maximum value of the retardation correction amount by the knocking control means C1; time measuring means C for measuring the elapsed time from the time when the high load state is removed until the high load state is resumed;
3, when the operating state of the internal combustion engine EG becomes the high load state again, the retardation amount is determined based on the retardation correction amount learned by the learning means C2 and the time measurement result of the timer C3. The gist of the present invention is a knocking control device for an internal combustion engine characterized by comprising an initial value setting means C4 for setting an initial value of the retardation correction amount of the knocking control means C1.

[Operation] The knocking control means C1 in the present invention operates when the operating state of the internal combustion engine EG becomes higher load than a predetermined operating state, and controls the basic ignition timing θB determined by the operating state and the internal combustion engine EG. The ignition timing θ is determined by the following equation based on the retardation correction amount θ for suppressing knocking that actually occurs to a predetermined level.

θ=θB−θ Meanwhile, the learning means C2 starts the following operation in the operating state in which the knocking control means C1 is activated. Since the load is higher than the predetermined operating state, the knocking control means C1 is naturally operating, and adjusts the ignition timing θ of the internal combustion engine EG while calculating the retardation correction amount θK for suppressing knocking of the internal combustion engine EG. has been decided. Therefore, this learning means C2 learns and stores the maximum value θl(m) of the retard angle correction amount θ executed by the knocking control means C1.

In order to increase the learning efficiency of the learning means C2, it is preferable to divide the predetermined operating state into smaller areas and store one learning value for each divided area.

The timing means C3 starts measuring the operating state in which the knocking control means C1 operates from the time when the internal combustion engine EG is disconnected, and the period until the operating state of the internal combustion engine EG becomes higher load than the predetermined operating state again. Measure. internal combustion engine EG
It measures how long the engine continues to operate under a light load operation that does not require activation of the knocking control means C1.

The initial value setting means C4 provides an initial value of the retardation correction amount of the knocking control means C1 as follows. The maximum value of the retardation correction amount that was previously necessary to suppress knocking of the internal combustion engine EG is obtained as a learning value in the learning means C2. At this time, if the timing means C3 obtains an extremely short timing result, the operating conditions such as the intake temperature of the internal combustion engine EG will not change much from the previous time.
It is expected that a retardation correction amount extremely close to the learned value of the learning means C2 will be necessary to prevent knocking of the internal combustion engine EG. Conversely, if the timing means C3 obtains an extremely long time measurement result, the internal combustion engine EG has been operating under low load for a long period of time, and the intake air temperature has also decreased, creating operating conditions in which knocking is less likely to occur. There is a high possibility that

At this point, it is expected that the learned value of the learning means C2 will give an unnecessarily large amount of retardation. In this way, it is clear that both the learning value of the learning means C2 and the time measurement result of the time measurement means C3 are correlated with the optimum retardation correction amount, so the initial value setting means C4 adjusts the learning value and the time measurement result. Based on this, the initial value of the retardation correction amount of the knocking control means C1 is set.

The learning value in the initial value setting means C4, the correlation between the timing result and the initial value are determined based on the system configuration of the internal combustion engine EG, and theoretically, when designing the internal combustion engine EG, Alternatively, it may be determined experimentally and given as a calculation formula, table, etc. Furthermore, if the calculation formulas, tables, etc. given in this way are used in conjunction with control such as updating by learning the aging of the internal combustion engine EG, more efficient ignition timing control can be achieved.

EXAMPLES Hereinafter, in order to explain the present invention more specifically, the present invention will be described in detail by giving examples.

[Example] First, Fig. 3 shows an example of a knocking control system equipped with a knocking control device.
1 is a schematic configuration diagram showing an internal combustion engine and its peripheral devices together with a block diagram of an electronic control circuit.

1 is the internal combustion engine body, 2 is the piston, 3 is the spark plug, 4
is an exhaust manifold, 5 is an oxygen sensor provided in the exhaust manifold 4 and detects the residual oxygen concentration in the exhaust gas, 6 is a fuel injection valve that injects fuel into the intake air of the internal combustion engine body 1, 7 is an intake manifold, and 8 is an oxygen sensor An intake air temperature sensor that detects the temperature of intake air sent to the internal combustion engine body 1, a knocking sensor 9 that detects knocking occurring in the internal combustion engine, a throttle valve 10, and a built-in idle switch 11 that opens the throttle valve. 14 is a surge tank that absorbs the pulsation of intake air, and 15 is an air flow meter that detects the amount of intake air.

16 is an igniter that outputs the high voltage necessary for ignition; 17 is a distributor that is linked to a crankshaft (not shown) and distributes the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder; and 18 is a distributor 17 The rotation angle sensor 19 outputs 24 pulse signals for one revolution of the distributor 17, that is, two revolutions of the crankshaft, and 19 outputs one pulse signal for one revolution of the distributor 17. 20 is an electronic control circuit as a control means, 21 is a key switch, 22 is a key switch 21
a battery that supplies power to the electronic control circuit 20 via;
24 represents an on-vehicle transmission, and 26 represents a vehicle speed sensor that detects the vehicle speed from the rotational speed of the output shaft of the transmission 24.

Also, to explain the internal configuration of the electronic control circuit 20, in the figure, 30 is a central processing unit that inputs and calculates data output from each sensor according to a control program, and performs processing for controlling the operation of various devices. (CPU), 31 is a read-only memory (ROM) in which control programs and initial data are stored.
, 32 is a random access memory (RAM) into which data input to the electronic control circuit 20 and data required for arithmetic control are temporarily read and written, 36 is an input port for inputting signals from each sensor, and 38 is an igniter 16 and an output port 39 for driving the fuel injection valve 6 provided in each cylinder.
is necessary for the common bus that interconnects each of the above elements. The input boat 36 has an oxygen sensor 5. Intake temperature sensor, knocking sensor 9° throttle sensor 11. Air flow meter 1
an analog input section (not shown) into which analog signals from 5 are A/D converted and input; and pulse signals (not shown) into which pulse signals from an idle switch (not shown) in the throttle sensor 11, a rotation angle sensor 18, and a cylinder discrimination sensor 19 are input. It consists of an input section.

Further, the output port 38 receives the ignition timing command from the CPU 30 and outputs the igniter 16 and the distributor 17.
The spark plug 3 of each cylinder outputs a control signal to the spark plug 3 of each cylinder according to the ignition timing θ.

That is, when the CPLJ 30 calculates the ignition timing θ,
Ignition by the spark plug is performed faithfully to the calculation result.

Next, prior to the ignition timing control related to the knocking control device of this embodiment, the basic control routine of the internal combustion engine will be explained based on the flowchart of FIG. 4, and then the ignition timing control executed therein will be explained. I will explain in detail.

As shown in FIG. 4, the basic control routine for the internal combustion engine 1 is started when the key switch 21 is turned on, and first performs initialization such as clearing the internal registers of the CPU 30 (step 100). In step 105, initial values of data used to control the internal combustion engine 1 are set, for example, a flag FF used as will be described later is set to O (step 105). Subsequently, the operating status of internal combustion@Kan 1, for example air flow meter 159 rotation angle sensor 18. Processing is performed to read the signals from the knocking sensor 9, etc. (step 110), and from the various data read in this way, the intake air ff1Q, rotation speed N, or load Q/N of the internal combustion engine 1 is determined.
A process is performed to calculate various values ω, which are the basis of control of the internal combustion engine 1 (step 120). Thereafter, based on the various aspects obtained in step 120, ignition timing control (step 130), which will be described in more detail later, and well-known fuel injection amount control (step 170) are performed. After completing step 170,
The process returns to step 110 and repeats the process described above.

Note that the control of the fuel injection amount here usually involves feedback control of the air-fuel ratio, and the basic fuel injection m determined based on the load Q/N of the internal combustion engine 1 is controlled by various factors such as an air-fuel ratio feedback correction coefficient. Synchronous injection is performed twice per rotation of the internal combustion engine 1 using the fuel injection amount corrected by the correction term, but fuel injection may be performed in place of air-fuel ratio feedback control in response to various operational demands of the internal combustion engine 1. Open control to increase the amount or its well-known counterpart may also be performed. The fuel injection amount control for these internal combustion engines is well known, so a description thereof will be omitted.

Next, using the flowcharts of FIGS. 5 and 6 and the explanatory diagrams of FIGS. 7 and 8, the ignition timing control step 13 is performed.
0 processing will be explained in detail.

First, the detailed processing of step 130 shown in FIG. 5 will be explained for each step. When the calculation of the load Q/N etc. in step 120 is completed, the basic ignition timing θB is calculated from the load, rotation speed, etc. in step 131,
Next, in the process of step 132, the load Q/N and rotational speed NE [ shown in FIG. 7 stored in the ROM 31 described above]
From the map showing the relationship between the engine speed and the engine speed, it is determined whether the current operating state is in the knocking control region (KC3 region). 9 Loads or high rotational speed,
This is to configure the system to execute processing for suppressing knocking in a region where knocking occurs frequently, and if the operating state is outside this KC8 region, the flag FF is reset to rOJ (step 134), the above-mentioned fuel injection control process (step 170)
Proceed to.

On the other hand, if it is determined in step 132 that it is within the KC3 area, step 136 is executed, and the contents of flag FF are determined. The flag FF is set at step 132 as described above.
Since the reset state is set when it is determined that the current state is outside the KC3 area, the F
When it is determined that F=O, it is determined that the previous operating state was outside the KC3 region, but has now moved into the KC3 region for the first time. Only in such a transient case, the subsequent processes of steps 138 to 150 are selectively executed, and in other cases, the process of step 152, which will be described later, is performed without executing the transient processes (steps 138 to 150). Move to.

At the beginning of the transition process, a flag FF is set (step 138) to prevent the following process from being executed again. Then, from the contents of the counter C, a search for the retard angle reduction angle θ is performed. Here, the counter C1 and the retard angle reduction of 0 are as follows. The interrupt routine shown in FIG.
], the contents of the flag FF are judged in step 200>, and the counter C is incremented by 1 only when the flag FF is in the reset state (step 202), otherwise counter C
is reset to rOJ (step 204). In this way, the counter C is reset when the operating state of the internal combustion engine 1 leaves the KC3 range, and represents the result of measuring the operating time of the internal combustion engine 1 outside the KC8 range.

Further, the retard angle reduction of 0 is the amount of correction of the ignition timing based on the timing result of the counter C, which is obtained by searching the table shown in FIG. 8 stored in the ROM 31. As shown in FIG. 8, as the elapsed time t of operation outside the KC8 area indicated by the contents of counter C increases, the value of retardation reduction 0 increases, and the elapsed time 3 The weight loss θT is 2
BiCA].

Once the retard angle impairment θ is retrieved as described above, the process proceeds to step 142, and the learned value θG is retrieved.

This is achieved by further subdividing the KC3 region described above in FIG. The maximum value θKm of the ignition timing retard correction amount θ, which is feedback-controlled so that the output is below a predetermined value, is memorized and learned. That is, the learned values θGA, θGB, θGC of each area are
, C is the maximum value θKm of the retard correction amount θ that was necessary to suppress knocking when the internal combustion engine 1 was in the previous operating state. Next, using the retardation reduction 0 and the learned value θG obtained as described above, an initial value θK of the retardation amount m used for this knocking suppression is determined.
S is calculated from the following equation.

The initial value θKS is set as the value obtained by subtracting the retardation reduction of 0 from θG, which is the maximum value of the retard correction amount learned before θKS=θG−〇th. Then, in order to prevent this value θKS from becoming an unreasonable value below "O", it is determined whether θKS ≧ 0 or not (step 146), and only when θKS < 0, θKs is set to "O".
(step 148), a so-called guard process is executed, and the θKS is stored in a predetermined storage area of the RAM 32 (step 150). In the ignition timing control based on the knocking detection value executed in the subsequent step 152, feedback control is performed to gradually retard the ignition timing so that the knocking detection signal from the knocking sensor 9 becomes equal to or less than a predetermined value. At this time, when the initial value θKs of the retard correction amount is stored in a predetermined storage area of the RAM 32 when the ignition timing control is executed for the first time, the value θKS is subtracted from the basic ignition timing θB calculated in step 131. The ignition timing is controlled using the value (θB−○KS>).

That is, based on the judgment in step 136, step 1 is directly executed without executing steps 138 to 150.
When the process moves to 52, the knocking sensor 9 is simply
Only when the output of This is because it is used. Note that when the retardation correction amount θK changes moment by moment in the processing of step 152, the maximum value of the retardation correction amount θ is learned for the next processing of steps 138 to 150 and is set to θG.
As IP! be done.

According to the knocking control device of this embodiment which controls the retardation correction amount θK as described above, the following operation occurs when the internal combustion engine 1 is operated as shown in FIG. 9, for example.

In Fig. 9, time is plotted on the horizontal axis, and when the load Q/N of the internal combustion engine fluctuates greatly in a short time (Fig. A), the value of counter C (
Figure B), the value of the retardation correction amount θ (Figure 0), and the intake air temperature (D
Figure 2) shows how the changes occur. As shown in the figure, the counter C starts counting up from the moment the load Q/N of the internal combustion engine 1 goes out of the KC3 range, so the more frequently the load Q/N fluctuates, the smaller the value of the counter C becomes. becomes. Furthermore, at this time, the internal combustion engine 1 is under a high load on average, so an increase in intake air temperature is observed, resulting in a situation where knocking is likely to occur.

Under the above operating conditions, the retardation correction amount θ is determined when the load Q/N is in the KC3 range and the knocking sensor 9
When the output exceeds a predetermined value, the output is increased by a predetermined value to control the ignition timing to the retarded side. Therefore, the characteristic rises to the right as shown in Figure 0. Moreover, when the load fluctuation is large and the period outside the KC3 region is short, the retard angle reduction θT determined according to the contents of the counter C is set proportionally smaller, so the initial value θKS of the retard angle correction amount becomes large. , a large ignition timing retardation will be implemented from the beginning.

The upward-sloping retardation correction amount represented by the dotted line in FIG. 9(C) is the case where a value obtained by subtracting a constant value from the conventional learning value is given as the initial value of the retardation correction amount. As can be easily understood from the comparison with the conventional control, according to the knocking control device of this embodiment, one internal combustion engine: K
When a large load change occurs near the boundary of the C3 region, the amount of retardation is immediately increased, and the occurrence of transient knocking in the internal combustion engine 1 can be suppressed. Moreover,
The retardation correction amount for this purpose is the maximum value θ of the previous retardation correction amount.
This skillfully utilizes l(m) and the operating time outside the KC3 region, thereby avoiding deterioration in the power characteristics of the internal combustion engine 1 due to unnecessary retard control.

[Effects of the Invention] As described above in detail with reference to the embodiments, the knocking control device for an internal combustion engine of the present invention uses the learning value of the retardation correction amount and the knocking control in order to determine the previous operating state of the internal combustion engine. The initial value of the knocking control means is set by skillfully using two parameters: a period of low load operation during which the means does not require operation.

Therefore, not only can knocking be suppressed with high responsiveness and accuracy over a wide range from low to high load areas, but also transient knocking can be prevented even with large load fluctuations. . Moreover, because of this, no unnecessary retardation is performed, and the fuel efficiency and emissions of the internal combustion engine are always maintained at their best, resulting in significantly improved power characteristics.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is an explanatory diagram of the relationship between the knocking control area and learning area of the conventional technology, and Fig. 3
4 is a flowchart of a basic control routine executed in the embodiment; FIG. 5 is a flowchart detailing the flow of ignition timing control within the basic control routine; FIG. 6 is a flowchart of the interrupt routine in the embodiment, FIG. 7 is an explanatory diagram of the relationship between the KC3 area and the learning area in the embodiment, FIG. 8 is an explanatory diagram of the retard angle reduction table in the embodiment, and FIG. The figure does not show an example of knocking control according to the embodiment, but shows timing offset. C1...Knocking control means C2...Knocking means C3...Timekeeping means C4...Initial value setting means 1...Internal combustion engine 3...Spark plug 9...Knocking sensor 20... electronic control circuit

Claims (1)

[Claims] When the load of the internal combustion engine is higher than a predetermined operating state,
knocking control means that determines the ignition timing of the internal combustion engine from a basic ignition timing determined by the operating state of the internal combustion engine and a retardation correction amount determined so that knocking occurring in the internal combustion engine is kept below a predetermined level; learning means for learning the maximum value of the retardation correction amount by the knocking control means; and learning means for learning the maximum value of the retardation correction amount by the knocking control means; a timer for measuring elapsed time; and a timer for measuring elapsed time; and when the operating state of the internal combustion engine becomes the high load state again, the retardation correction amount is determined based on the retard correction amount learned by the learning means and the time measurement result of the timer. A knocking control device for an internal combustion engine, comprising: initial value setting means for setting an angle amount as an initial value of a retard angle correction amount of the knocking control means.