JPH0799136B2 - Engine knocking controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine knocking control device, and more particularly to an engine knocking control device that performs anti-knocking control when engine vibration exceeds a predetermined determination level. Is.

(Prior art) Before the flame propagation after ignition in the combustion chamber, the unburned mixed gas spontaneously ignites and abruptly burns, and a shock wave with a frequency component of 5 KHz to 10 KHz is usually generated. As a method of preventing this knocking, a vibration sensor is attached outside the combustion chamber of the engine, and when the vibration exceeds a predetermined determination level, the combustion temperature is lowered by lit the mixed gas or by delaying the ignition timing. Preventing the occurrence of knotting is taking place. For example, in JP-A-56-47663, the occurrence of knocking is prevented by delaying the ignition timing. Further, a processing method when an abnormality occurs in the vibration sensor is described.

By the way, conventionally, a value obtained by multiplying the average value of the vibration output from the vibration sensor by a fixed value is used as the vibration determination level when controlling the knocking. In this case, if the determination level is too low, the knocking will be over-controlled, so it will be set to a high value and the prevention of the knocking will be incomplete. Further, since it is not easy to change the settings due to variations in the vibration sensor or changes over time, a great inconvenience occurs. Furthermore, if knocking occurs before the determination level is set, a heavy load is placed on the engine.

(Problems to be Solved by the Invention) The present invention eliminates the drawbacks of the above-mentioned conventional example, sets a notking determination level without causing knocking in a high load region where the knocking is severe, and wastes due to overcontrol of the notking. Provided is a knocking control device for an engine, which eliminates ignition timing retardation and fuel increase, and prevents occurrence of knocking with high accuracy.

(Means for Solving the Problem) As one means for solving this problem, one embodiment of the engine knocking control device of the present invention shown in FIG.
Vibration sensor that measures the vibration generated in the combustion chamber of the engine
100, an operating state detecting means 103 for detecting the operating state of the engine, and the engine is controlled to prevent the occurrence of knocking when the vibration measured by the vibration sensor 100 exceeds a predetermined knocking determination level, and the operation is performed. State detection means
Based on the output of 103, the engine control means 101 for retarding the ignition timing or increasing the fuel amount when the operating state is in the enrichment zone, and the ignition timing retarding or fuel increasing state by the engine control means, A determination level setting means 102 for setting the peak value of the output value of the vibration sensor as the knocking determination level is provided.

(Operation) In such a configuration, the engine control means 101 controls the anti-knocking when the output value from the vibration sensor 100 is higher than the knocking judgment level set by the judgment level setting means 102. When the operating state detecting means 103 detects that the engine is in the enriched zone by the level setting means 102, the engine control means 101 delays the ignition timing or increases the fuel amount and puts it in a state where knocking cannot occur. The peak value of the output value of the vibration sensor 100 in this state is set.

Embodiment An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

First, the characteristics of the present embodiment will be clarified by comparing the conventional knock detection circuit of FIG. 8 with the circuit of FIG. 2 corresponding to the conventional knock detection circuit of the present embodiment.

In Fig. 8, the frequency related to the knocking, for example, the vibration of 5KHz to 10KHz is extracted from the output of the vibration sensor from the vibration source by the bandpass filter (BPF) and is averaged by being delayed by the RC circuit. Then, a value obtained by multiplying by a gain set by the number of revolutions of the engine is used as a determination level, and compared with the output of the vibration sensor, the output of knock detection is obtained.

On the other hand, in FIG. 2, the bandpass filter (BP
The peak value of the output from F) is held by the peak hold circuit, and this peak value is selected by the judgment level setting circuit under predetermined conditions and set as the judgment level. Other operations are the same. As described above, the feature of the present embodiment resides in the determination level setting method.

FIG. 3 is a specific configuration diagram of the engine and the engine knocking control device of the present embodiment. For simplification,
The intake air temperature sensor, the cooling water temperature sensor, etc., which are not directly related to the features of this embodiment, are omitted. In this embodiment, the engine
The control unit (ECU) controls knocking.

1 is an air flow meter for measuring the intake air amount Qa, 2 is an injector for injecting fuel by the injection amount Ti, and 3 is ignition timing
Ignition coil for generating a high voltage on Ig, 4 is a distributor for sending the high voltage from ignition coil 3 to ignition plug 9, 4a is a rotation speed meter for measuring engine speed Ne, and 5 is engine combustion. A vibration sensor for measuring the vibration of the chamber 6, 6 is a combustion chamber, 7 is an engine control unit (ECU), 8 is a throttle valve interlocked with an accelerator, and 9 is an ignition plug.

The ECU 7 is a fuel injection amount based on the intake air amount Qa from the air flow meter 1 and the engine speed Ne from the speed meter 4a.
Calculate Ti and ignition timing Ig. Actually, the intake air temperature, throttle valve opening, cooling water temperature, oxygen concentration in the exhaust gas, etc., which are not shown, are input and corrected, but they are omitted in this example for simplification. In addition, air conditioner control and alternator power generation control are also performed as outputs, but this is also not described in detail. In the present embodiment, the ECU 7 performs effective control for preventing knocking based on the vibration value P from the vibration sensor 5 mounted outside the combustion chamber 6 of the engine.

Fig. 4 shows the block diagram of the ECU 7. 71 is a CPU, 72 is a third
The ignition timing Ig is sent to the ignition circuit 30 such as the ignition coil 3 in the figure, and the combustion injection amount is sent to the injector vibration circuit 20.
A timer that sends Ti, 73 is a RAM for auxiliary storage, 74 is a ROM that stores the operating procedure of the ECU 7 and various constants, 75 is the intake air amount Qa from the air flow meter, and the rotation speed N from the rotation speed meter
e, an A / D converter for converting an analog input value such as the peak value Pk of the vibration P from the vibration sensor into a digital value, and 76 is an input circuit for extracting the peak value Pk of the vibration P from the vibration sensor.

FIG. 5 (a). The flowchart of the decision level learning by ECU7 is shown in (b).

First, when the learning condition is satisfied, that is, when the engine is in a steady operation for a predetermined period of time (usually divided into zones such as feedback zone, enrich zone, etc.), an interrupt occurs. , Fig. 5 (a)
Enter the flow of. In step S50, the ignition timing is delayed during learning and the engine is operated by over-litting, so alternator power generation is stopped to compensate for output loss, and this is stopped when the air conditioner is used. Next, in step S51, the ignition timing retard angle amount R _ET and the fuel increase amount A stored in the ROM 74 during learning.
_f is read to the retard amount C _ret and the fuel increase amount C _Af in the RAM 73.
Here, the ignition timing Ig is represented by Ig = Igo + Ck + C _ret , the fuel injection pulse width Ti is represented by Ti = Tp × _CF × C _Af , Igo is the basic ignition timing, Ck is the retard amount during knock control, and Tp is The basic fuel injection pulse, C _F, is a collection of various correction factors. Since the predetermined values for the retard amount C _ret and the fuel increase amount C _Af are read at step S51, the engine operates more retarded on the retard side.

At step S52, the down counters C ₁ and C ₂ in the timer 72 are set to a predetermined number. Here, the number of counters C ₁ sets the time until the engine is in a stable operating state after over-litting on the retard side in step S51, and the number of counters C ₂ sets the number of learning times. Therefore, the condition is C ₁ <C ₂ . Further, in step S52, the retarding amount C of the knocking control is
k is set to "0" and returns.

Next, when an interrupt occurs at TDC (top dead center), other control not shown is also performed. However, if the learning condition is satisfied and after passing through FIG. 5 (a), FIG. The flow of b) is entered. Therefore, the flow chart of FIG. 5 (b) is obtained by extracting the portion according to this embodiment.

First, in step S60, the peak value Pk of the vibration P from the vibration sensor input from the input circuit 76 is input, and the RAM 7
It is read by Ad in 3. In step S61, a reset pulse is output to reset the peak hold circuit in the input circuit 76. In step S62, it is checked whether the operating condition is the same as the previous zone. If you want to pass first, proceed to YES. If the driving state changes from the previous time and the zone changes, the process proceeds to step S70 to stop learning. If the zone is the same as the last time, go to Step S63
FIG counter C _1, C ₂ that is excisional at step S52 in (a) and one count-down, and a checking whether the counter C ₁ in step S64 is "0", the engine if not "0" stable Return as it is to wait.

If the counter C ₁ reaches "0" with stability when the engine learns, then in step S65 the counter C ₂ becomes "0".
Check whether or not. Since the counter C ₂ is not "0" at the time of learning, the process proceeds to step S66, and at step S66, the determination level Le at the previous learning is read from the learning table shown in FIG. 5 (c). Although the determination level Le is assigned according to the engine speed in the present embodiment, the determination level Le is not limited to this. In step S67, the Ad that has set the peak value Pk of the vibration sensor input in step S60 is compared with the previous judgment level Le. If Ad> Le, the content of Ad is moved to Le, and the next time it is input this time. The peak value Pk thus obtained becomes the value of Le. If Ad ≦ Le, Le remains unchanged. Step S69
Then put Le into the learning table and return. After that, Le stored in the learning table is used as a determination level for performing the knocking control corresponding to the rotation speed.

When the counter C ₂ becomes “0” at step S65, the learning period has elapsed, so at step S70 the alternator power generation stopped at step S50 is started, and when the air conditioner is used, it is turned on and the retard angle amount C _ret , The fuel increase amount C _Af is reset and the learning ends.

6 (a) and 6 (b), as shown in FIGS. 5 (a) and 5 (b), when all the cylinders are set to the retard side during learning and the switch is set to the latch, the output is extremely reduced and the fuel consumption is increased. Therefore, a flow chart is shown in which only one cylinder is latched for learning. In the case of four cylinders, if the two different cylinders are learned in this manner, the knocking control of the engine can be sufficiently performed.

First, in FIG. 6A, only a predetermined cylinder, in the present example, only the # 1 cylinder is set to the latch. When the learning condition is satisfied as in FIG. 5A, an interrupt occurs. At step S80, the ignition timing of all cylinders is retarded, the # 1 cylinder is set to LITCH, and the other cylinders are set to lean or lean. In step S81 the Notsukingu control amount Ck ₁ ~Ck ₄ in all the cylinders to "0", FIG. 5 (a)
Similarly, the counters C ₁ and C ₂ are set and the process returns.

The process of FIG. 6 (b) is performed by interruption of the portion where the # 1 cylinder has reached TDC (top dead center). First, in step S90, the peak hold circuit of the input circuit 76 is reset. After that, the process waits until a predetermined crank angle is reached in step S91, and when the predetermined crank angle is reached, the peak value Pk of the vibration P of the vibration sensor up to the present after resetting in step S90 is performed.
Store in Ad of RAM73. This is because the vibration of only the latch cylinder is detected. In FIG. 6 (b), the timing at which knocking occurs is approximately between T ₁ and T ₂ shown in FIG. 6 (c), so the measurement was limited to this period. The method of limiting the period is not limited to the flow of this example. Step S93 to Step S10
Up to 1, steps S62 to S70 in Fig. 5 (b)
Since it is similar to the above, it will not be repeated. In this example, all the cylinders are shifted to the retard side and one cylinder is set to the latch, but this combination is not limited to this example and various combinations are possible.

As described above, the learning level of the knocking that is learned is the peak value of the vibration generated by the engine that is in the state where the knocking does not occur due to the movement to the retard side of the ignition timing, or the latching. This determination level is almost the maximum level at which the occurrence of knocking can be detected in advance. A more accurate determination level can be set by changing the amount of movement toward the retard side and the amount of fuel increase depending on the structure of the engine and the like. Further, since the determination level can be set without causing knocking, there is no load on the engine.

Further, in the above-described example, when the learning conditions are set, the learning is performed by creating a state in which no knocking occurs due to the movement to the retard side or the fuel increase, but the learning condition determination flowchart shown in FIG. Therefore, you can start learning.

In FIG. 7, first, in step S110, it is checked whether the ignition timing Ig is between a stable predetermined value a ₁ and a ₂ at which knocking does not occur by an interrupt when the engine is in a steady state for a predetermined time. Then, in step S111, the fuel injection amount Ti
Also checks if it is between a predetermined value b ₁ and b ₂ at which no knocking occurs. When both are in a stable state, the counters C ₁ and C ₂ are set at step S112, and the determination level shown in FIG. 5 (b) or FIG. 6 (b) is learned.
If either of them is out of stable condition, it returns without doing anything. By doing so, it is not necessary to make a learning time, and the learning can be automatically performed when the engine is stably operated for a predetermined time during normal traveling.

In this embodiment, the movement toward the retard angle side and the entrainment are performed at the same time, but this may be controlled by only one side. or,
The technical idea of the present invention is to accurately create a control amount corresponding to a change in conditions, which makes it disadvantageous to measure a limit value by causing it once such as knocking. It can also be applied to the creation of controlled variables.

(Effect of the invention) According to the present invention, in a high load region severe to knocking, by setting the knocking determination level without causing knocking, unnecessary ignition timing retardation and fuel increase due to over-control of knocking are eliminated, It is possible to determine the knocking control that accurately prevents the occurrence of the knocking.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an engine knocking control device of the present embodiment, FIG. 2 is a diagram of an example of a knock detection circuit of an engine knocking control device of the present embodiment, and FIG. 3 is a diagram of an engine and engine of the present embodiment. A concrete configuration diagram of the knocking control device, FIG. 4 is a configuration diagram of the engine control unit of the present embodiment, and FIGS. 5 (a) and 5 (b) are determination levels of the knocking control device of the engine of the present embodiment. FIG. 5 (c) is a learning table diagram used for creating a decision level, and FIGS. 6 (a) and 6 (b) are other flow charts for creating a decision level of the engine knocking controller of this embodiment. 6 (c) is a diagram for explaining the decision level creation timing of FIG. 6 (b), FIG. 7 is a flow chart for decision level creation during normal running, and FIG. 8 is a conventional engine knocking control device. A Notsuku detecting circuit example diagram. In the figure, 1 ... Air flow meter, 2 ... Injector,
3 ... Ignition coil, 4 ... Distributor, 4a ... Rotation speed meter, 5 ... Vibration sensor, 6 ...
Combustion chamber, 7 ... ECU, 8 ... Slot valve, 9 ... Spark plug, 71 ... CPU, 72 ... Timer, 73 ... RAM, 74 ...
ROM, 75 ... A / D converter, 76 ... Input circuit, 100 ... Vibration sensor, 101 ... Notking control means, 102 ... Judgment level setting means, 103 ... Combustion condition setting means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Kawate 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP 61-207877 (JP, A) JP 59- 119067 (JP, A) JP 61-108873 (JP, A)

Claims (4)

[Claims] 1. A vibration sensor for measuring vibration generated in a combustion chamber of an engine, an operation state detecting means for detecting an operation state of the engine, and a case where the vibration measured by the vibration sensor exceeds a predetermined knocking determination level. In addition to performing engine control to prevent the occurrence of knocking, based on the output of the operating state detecting means, engine control means for retarding the ignition timing or increasing the fuel amount when the operating state is in the enriched zone, A knocking control device for an engine, comprising: determination level setting means for setting a peak value of an output value of the vibration sensor as the knocking determination level when the ignition timing is retarded or the fuel amount is increased by the engine control means. 2. An engine control means for retarding ignition timing or increasing fuel when the engine continues to operate normally for a predetermined time in the entrainment zone. Engine knocking control device. 3. The knocking control system for an engine according to claim 1, wherein the engine control means sets the fuel injection amount and the ignition timing based on the intake air amount, the engine speed, and the like. . 4. The engine according to claim 1, wherein the determination level setting means sets a peak value of vibration of the engine during a predetermined crank angle after top dead center to a knocking determination level. Notting control device.