JP6992522B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to a control device for an internal combustion engine that performs knock control control by adjusting the ignition timing to suppress the occurrence of knocking.

In knock control control, the ignition timing is retarded when knocking occurs. If deposits derived from unburned fuel, lubricating oil, etc. progress in the combustion chamber of an internal combustion engine, the substantial volume of the combustion chamber decreases, the compression ratio increases, and knocking tends to occur.

On the other hand, Patent Document 1 discloses a control device for an internal combustion engine that adjusts the ignition timing to the retard side as the deposit increases in knock control control.

Japanese Unexamined Patent Publication No. 2011-256725

By the way, knocking is likely to occur during high-load operation. Therefore, when the deposit is accumulated and knocking is likely to occur, knocking is particularly likely to occur when acceleration is required and high load operation is performed, and the ignition timing is liable to occur through knock control control. Is further retarded. In addition to adjusting the ignition timing to the retard side in consideration of deposit accumulation, if such a retard is performed, the amount of ignition timing retard becomes too large, and acceleration is required. Nevertheless, the output may be insufficient and the desired acceleration may not be possible.

Hereinafter, means for solving the above problems and their actions and effects will be described.
The internal combustion engine control device for solving the above problems is applied to an internal combustion engine equipped with an oil jet that injects lubricating oil toward the back surface of the piston, and retards the ignition timing when knocking occurs. Knock control control is performed. In this control device, when the amount of retardation of the ignition timing according to the accumulated amount of deposit in the combustion chamber of the internal combustion engine is equal to or more than a predetermined amount in the knock control control, knocking with a predetermined level or higher is generated. On condition that the piston is cooled, the piston cooling control is started by injecting the lubricating oil by the oil jet.

According to the above configuration, when high-intensity knocking occurs in a situation where deposit accumulation is progressing and the ignition timing is already adjusted to the retard side, the piston is cooled by the oil jet. Therefore, knocking is less likely to occur due to a decrease in temperature in the combustion chamber, and the retard angle of the ignition timing due to knock control control is suppressed. That is, according to the above configuration, it is possible to suppress the progress of the retardation of the ignition timing from the state in which the ignition timing is already adjusted to the retard side in consideration of the accumulation of the deposit. Therefore, it is possible to prevent the amount of retardation of the ignition timing from becoming too large and causing an output shortage.

The schematic diagram which shows the relationship between the control device of the internal combustion engine of one Embodiment, and the internal combustion engine which is the control target of the control device. A flowchart showing the flow of a series of processes for starting the piston cooling control. The graph which shows the relationship between the hydraulic pressure and the rgknk retard angle amount in a piston cooling control. A flowchart showing a flow of a series of processes related to the end of piston cooling control. A timing chart showing the transition of ignition timing in the conventional knock control control. A timing chart showing the transition of the ignition timing and the transition of the state of the oil jet in the knock control control of the control device of the embodiment.

Hereinafter, an embodiment of the control device for an internal combustion engine will be described with reference to the drawings.
As shown in FIG. 1, a spark plug 12 is provided in the combustion chamber 11 of the internal combustion engine 10. Further, the cylinder block 13 of the internal combustion engine 10 is provided with a knock sensor 20 for detecting the knocking intensity, which is an index value indicating the magnitude of the energy of vibration due to knocking.

Further, an oil jet 31 is provided in the cylinder block 13 of the internal combustion engine 10. The oil jet 31 injects a part of the lubricating oil pumped from the oil pan by the oil pump 30 toward the back surface of the piston. The oil pump 30 is a variable capacity type oil pump whose discharge amount can be changed, and the oil jet 31 is provided with a control valve for stopping the injection of lubricating oil.

Various controls related to the operation of the internal combustion engine 10 are performed by the electronic control device 100, which is a control device for the internal combustion engine. The electronic control device 100 includes a CPU that executes various controls, a memory that stores information necessary for the control, an input port for inputting a signal from the outside, an output port for outputting a command signal to the outside, and the like. It is provided, and various controls are executed by the CPU executing the program stored in the memory.

Various sensors for detecting the operating state of the internal combustion engine 10 are connected to the input port of the electronic control device 100. As these sensors, in addition to the knock sensor 20, a crank angle sensor 21 for detecting the crank angle which is the rotation phase of the crankshaft, an air flow meter 22 for detecting the intake air amount of the internal combustion engine 10, and the like are connected. Has been done. Then, the detection signals of these sensors are input to the electronic control device 100 through the input port. The electronic control device 100 calculates the engine rotation speed NE from the detection signal of the crank angle sensor 21. Further, the electronic control device 100 is a ratio of the intake air amount per one combustion cycle of one cylinder to the reference intake air amount using the intake air amount and the engine rotation speed NE, and is a value obtained by quantifying the in-cylinder filling air amount. The engine load KL is calculated.

On the other hand, the output port of the electronic control device 100 has actuators required for engine control, such as an igniter 14 that generates a high-voltage current required for ignition of the air-fuel mixture by the spark plug 12, a control valve of the oil jet 31, and an oil pump 30. Kind of drive circuit is connected. The electronic control device 100 performs various calculations based on the detection signals of the above sensors, and also executes drive control of the actuators based on the calculation results to perform engine control.

The electronic control device 100 executes knock control control for adjusting the ignition timing according to the knocking occurrence state. In the knock control control, the electronic control device 100 determines that knocking has occurred when the knocking intensity detected by the knock sensor 20 is equal to or greater than the second threshold value Y2, and the knocking intensity is less than the second threshold value Y2. Sometimes it is determined that knocking has not occurred. Then, the electronic control device 100 retards the ignition timing when knocking occurs. On the other hand, the electronic control device 100 advances the ignition timing when knocking does not occur.

More specifically, the electronic control device 100 calculates the base ignition timing based on the engine rotation speed NE and the engine load KL. Then, the retard angle amount is calculated and reflected in the ignition timing setting, and the timing on the retard side of the base ignition timing is set as the ignition timing by the amount of the retard angle amount. The retard angle amount is an agknk retard angle amount for suppressing the occurrence of knocking, reflecting the susceptibility to knocking due to changes in fuel properties and individual differences in the internal combustion engine 10, and the deposit to the combustion chamber 11. It is calculated as the sum of the amount of rgknk retard angle for suppressing the occurrence of knocking, reflecting the susceptibility to knocking due to deposition. The agknk retard angle amount and the rgknk retard angle amount are updated according to the presence or absence of knocking.

When the knocking intensity is equal to or higher than the second threshold value Y2 and it is determined that knocking has occurred, the agknk retard angle amount is increased according to the magnitude of the knocking intensity. Specifically, each time it is determined that knocking has occurred, the value is added and increased, but the magnitude of the value added at that time increases as the knocking strength increases.

Further, the agknk retard angle amount is reduced when the knocking intensity is less than the second threshold value Y2 and it is determined that knocking has not occurred. Specifically, each time it is determined that knocking has not occurred, a certain value is subtracted to make it smaller.

The rgknk retard angle amount determines that knocking has occurred when the operating state specified based on the engine rotation speed NE and the engine load KL is in a predetermined operating region where deposits are likely to accumulate in the combustion chamber 11. Then, it is increased according to the magnitude of the knocking strength. Similar to the agknk retard angle amount, the rgknk retard angle amount is also increased by adding a value each time it is determined that knocking has occurred, but the magnitude of the value added at that time is the knocking intensity. The larger it is, the larger it becomes.

Further, the rgknk retard angle amount is reduced when it is determined that knocking has not occurred when the operating state is in a predetermined operating region where deposits are likely to be accumulated in the combustion chamber 11. Also at this time, as with the agknk retard angle amount, a constant value is subtracted and reduced each time it is determined that knocking has not occurred.

That is, unlike the agknk retard angle amount, the rgknk retard angle amount is updated only when the operating state is in the predetermined operating area, and is not updated when the operating state is not in the predetermined operating area. As the deposition of deposits progresses in the combustion chamber 11, the substantial volume of the combustion chamber 11 decreases, the compression ratio increases, and knocking is likely to occur. Therefore, the rgknk retard angle amount becomes large when the deposit amount is large and knocking is likely to occur. That is, the rgknk retard angle amount is the retard angle amount of the ignition timing according to the deposit amount in the combustion chamber 11.

By the way, knocking is likely to occur during high-load operation. Therefore, when the deposit is accumulated and knocking is likely to occur, knocking is particularly likely to occur when acceleration is required and high load operation is performed, and the ignition timing is liable to occur through knock control control. Is further retarded. In addition to adjusting the ignition timing to the retard side in consideration of deposit accumulation, if such a retard is performed, the amount of ignition timing retard becomes too large, and acceleration is required. Nevertheless, the output may be insufficient and the desired acceleration may not be possible.

Therefore, the electronic control device 100 executes the piston cooling control for cooling the piston by the oil jet 31 together with the knock control control. Next, this piston cooling control will be described with reference to FIGS. 2 to 4. The flowchart of FIG. 2 shows a flow of a series of processes for determining whether or not to start the piston cooling control, and the flowchart of FIG. 4 shows a series of processes for determining whether or not to end the piston cooling control. It shows the flow.

In the series of processes shown in FIG. 2, when the knock control control is executed and the piston cooling control is not executed, the CPU executes the program stored in the memory of the electronic control device 100 at a predetermined cycle. It is realized by executing it repeatedly.

When the series of processes shown in FIG. 2 is started, the electronic control device 100 determines in step S100 whether or not the rgknk retard angle amount is a predetermined amount X1 or more. The predetermined amount X1 is set to a size that can be determined to be in a state where knocking is likely to occur due to the accumulation of the deposit, based on the fact that the rgknk retard angle amount is the predetermined amount X1 or more.

When it is determined in step S100 that the rgknk retard angle amount is a predetermined amount X1 or more (step S100: YES), the electronic control device 100 determines in step S110 whether or not the knocking strength is the third threshold value Y3 or more. do. The third threshold value Y3 is a threshold value for determining that high-intensity knocking has occurred based on the fact that the knocking intensity is equal to or higher than the third threshold value Y3, and it is determined whether or not knocking has occurred. It is a value larger than the second threshold value Y2, which is a threshold value for knocking.

If it is determined in step S110 that the knocking strength is equal to or higher than the third threshold value Y3 (step S110: YES), the electronic control device 100 starts piston cooling control in step S120. In the piston cooling control, the electronic control device 100 operates the control valve of the oil jet 31 to inject lubricating oil from the oil jet 31 toward the piston, and also operates the oil pump 30 to operate the oil jet 31. Adjust the oil pressure of the lubricating oil supplied to.

As shown in FIG. 3, the hydraulic pressure supplied to the oil jet 31 in the piston cooling control is determined to be higher as the rgknk retard angle amount is larger, depending on the rgknk retard angle amount.

When the piston cooling control is started through step S120 in this way, the electronic control device 100 ends this series of processes. If the electronic control device 100 makes a negative determination in step S100 or step S110 (step S100: NO or step S110: NO), the electronic control device 100 temporarily ends this series of processes without starting the piston cooling control.

When the piston cooling control is being executed, the series of processes shown in FIG. 4 is repeatedly executed at a predetermined cycle. The series of processes shown in FIG. 4 is realized by the CPU executing a program stored in the memory of the electronic control device 100.

When the series of processes shown in FIG. 4 is started, the electronic control device 100 determines in step S200 whether or not the knocking strength is equal to or less than the first threshold value Y1. The first threshold value Y1 is a threshold value for determining that knocking does not occur even if the piston cooling control is terminated based on the knocking intensity being equal to or less than the first threshold value Y1, and knocking occurs. It is a value smaller than the second threshold value Y2, which is a threshold value for determining whether or not it is present.

When it is determined in step S200 that the knocking strength is equal to or less than the first threshold value Y1 (step S200: YES), the electronic control device 100 ends the piston cooling control in step S210. Here, the electronic control device 100 operates the control valve of the oil jet 31 to stop the injection of the lubricating oil from the oil jet 31.

When the piston cooling control is completed through step S210 in this way, the electronic control device 100 ends this series of processes. Further, when the electronic control device 100 makes a negative determination in step S200 (step S200: NO), the electronic control device 100 temporarily ends this series of processes without ending the piston cooling control.

Next, the operation of the present embodiment will be described with reference to FIGS. 5 and 6. FIG. 6 is a timing chart showing the transition of the ignition timing by the knock control control when the piston cooling control is executed in the present embodiment, and FIG. 5 is a case where the piston cooling control is not executed in the same situation as a comparative example. It is a timing chart which shows the transition of the ignition timing of. Note that FIGS. 5 and 6 show changes in the ignition timing under the condition that the deposit is already deposited in the combustion chamber 11 and the rgknk retard angle amount is equal to or higher than the third threshold value Y3.

As shown in FIG. 5, when the piston cooling control is not executed, acceleration is required to shift to high load operation, and when it is determined that high-intensity knocking occurs at time t10, knock control control is performed. The ignition timing is significantly retarded through. Then, the ignition timing is retarded up to the region where acceleration failure occurs on the retard side of the broken line. Therefore, in this case, the amount of retardation of the ignition timing becomes too large, and the output is insufficient even though acceleration is required, so that desired acceleration cannot be performed. When the high load operation is no longer performed and it is determined that knocking has not occurred at time t20, the ignition timing is gradually advanced through the knock control control.

On the other hand, as shown in FIG. 6, in the case of the present embodiment, when acceleration is required and the operation shifts to high load operation, it is determined that high-intensity knocking occurs at time t10 (). Step S110: YES), the piston cooling control is started (step S120), and the lubricating oil is injected by the oil jet 31. As a result, the piston is cooled by the injection of the lubricating oil, knocking is less likely to occur from time t11, the knocking strength is lowered, and the progression of the retard of the ignition timing through the knock control control is slowed down. ..

Then, when the knocking intensity becomes less than the second threshold value at time t12 and it is determined that knocking has not occurred, the ignition timing is gradually advanced through the knock control control. After that, when the knock intensity becomes equal to or less than the first threshold value at time t13, the piston cooling control is terminated and the injection of the lubricating oil from the oil jet 31 is stopped.

That is, in the present embodiment, when high-intensity knocking occurs in a situation where deposit accumulation is progressing and the ignition timing is already adjusted to the retard side, the piston is cooled by the oil jet 31. .. Therefore, knocking is less likely to occur due to a decrease in temperature in the combustion chamber 11, and the retardation of the ignition timing due to knock control control is suppressed. As a result, it is avoided that the ignition timing is retarded up to the region where the acceleration failure occurs on the retard side of the broken line.

The effect of this embodiment will be described.
(1) It is possible to suppress the progress of the retardation of the ignition timing from the state where the ignition timing is already adjusted to the retard side in consideration of the accumulation of the deposit. Therefore, it is possible to prevent the output from being insufficient because the amount of retardation of the ignition timing becomes too large. As a result, it is possible to prevent an acceleration failure due to insufficient output even though an acceleration request is made.

(2) In a situation where knocking is likely to occur due to deposit accumulation, the agknk retard angle amount for suppressing knocking due to fuel properties or individual differences in the internal combustion engine 10 is updated and becomes large. It can be suppressed. That is, it is possible to suppress that the agknk retard angle amount is updated and becomes large even though knocking occurs due to the accumulation of the deposit.

(3) Since the piston cooling control is executed on the condition that the amount of rgknk retard angle is large and the deposit is accumulated, oil is injected into the dark clouds by the oil jet 31. It is possible to suppress the consumption of the lubricating oil without doing so.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-The oil pump 30 is not limited to the variable capacity type oil pump. It may be an electric oil pump. In the case of an electric oil pump, the hydraulic pressure supplied to the oil jet 31 can be changed according to the rgknk retard angle amount by adjusting the drive amount of the oil pump. In addition, a return passage for returning a part of the lubricating oil discharged from the oil pump to the oil pan and a regulating valve for adjusting the amount of lubricating oil returned to the oil pan through the return passage are provided, and excess lubricating oil is discharged to the oil pan. By returning to, the oil pressure of the lubricating oil supplied to the oil jet 31 can be changed without adopting an electric oil pump or a variable capacity type oil pump.

-The configuration that changes the hydraulic pressure supplied to the oil jet 31 according to the rgknk retard angle amount is omitted, and only the execution / stop of the injection of the lubricating oil from the oil jet 31 is switched regardless of the magnitude of the rgknk retard angle amount. Can also be adopted.

-Although the configuration in which the amount of retard angle is increased as the knocking strength is increased is illustrated, a configuration in which the amount of retard angle is increased by a fixed amount each time the occurrence of knocking is determined may be adopted.
-The control device for an internal combustion engine is not limited to one that includes a CPU and a memory and executes software processing. For example, a dedicated hardware circuit (for example, ASIC) for hardware processing of at least a part of the software processed in the above embodiment may be provided. That is, the control device for the internal combustion engine may have any of the following configurations (a) to (c). (A) A processing device that executes all controls according to a program and a program storage device such as a memory for storing the program are provided. (B) A processing device and a program storage device that execute a part of control according to a program, and a dedicated hardware circuit that executes the remaining control are provided. (C) A dedicated hardware circuit for executing all controls is provided. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits. That is, various controls may be performed by a processing circuit comprising at least one of one or more software processing circuits and one or more dedicated hardware circuits.

10 ... Internal combustion engine, 11 ... Combustion chamber, 12 ... Spark plug, 13 ... Cylinder block, 14 ... Igniter, 20 ... Knock sensor, 21 ... Crank angle sensor, 22 ... Air flow meter, 30 ... Oil pump, 31 ... Oil jet, 100 ... Electronic control device.

Claims (1)

It is applied to an internal combustion engine equipped with an oil jet that injects lubricating oil toward the back surface of the piston, and is a control device for an internal combustion engine that performs knock control control that retards the ignition timing when knocking occurs.
In the knock control control, the final ignition timing is set on the retard side by the sum of the first retard angle amount and the second retard angle amount from the base ignition timing calculated based on the operating state of the internal combustion engine. Set as the time,
The first retard angle amount is updated according to whether or not the knocking has occurred regardless of the operating state.
The second retard angle amount is updated depending on whether or not the knocking has occurred, only when the operating state is in a predetermined operating region where deposits are likely to accumulate.
On condition that when the second retard angle amount is equal to or more than a predetermined amount in the knock control control, knocking having a strength equal to or higher than a predetermined level occurs.
A control device for an internal combustion engine that starts piston cooling control for cooling the piston by injecting lubricating oil by the oil jet.

Images