JP7095510B2 - Internal combustion engine control device - Google Patents

Description

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

Patent Document 1 discloses an internal combustion engine capable of stopping the injection of oil from an oil jet. In the internal combustion engine described in Patent Document 1, the execution conditions of the oil jet are set in order to achieve both the reduction of the fuel consumption rate and the cleaning effect of the oil jet.

Japanese Unexamined Patent Publication No. 2014-80888

By the way, if the temperature of the piston is excessively low, particulate matter is likely to be generated as the fuel burns. Therefore, it is desired to improve the control of the oil jet in order to reduce the number of particulate matter contained in the exhaust gas.

Hereinafter, means for solving the above problems and their actions and effects will be described.
The control device of the internal combustion engine for solving the above-mentioned problems is a cutoff that shuts off the oil jet that injects oil toward the piston and the oil supply to the oil jet to stop the injection of oil from the oil jet. Applies to internal combustion engines equipped with a mechanism. This control device is an oil jet that shuts off the supply of oil to the oil jet and stops the injection of oil from the oil jet by operating the shutoff mechanism when the temperature of the piston is lower than the operating temperature. It has a control unit. Then, the oil jet control unit starts fuel injection to stop fuel injection until a predetermined period elapses after restarting fuel injection, and from engine start until a predetermined period elapses. , The operating temperature is raised as compared with the case where the fuel injection is restarted after the fuel cut is started and the predetermined period elapses, or the engine is started and the predetermined period elapses. ..

During the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started, if the oil jet is operated, the piston may become too cold and the temperature may become too low. As a result, particulate matter is likely to be generated as the fuel burns.

On the other hand, according to the above configuration, the operating temperature is raised during the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started. Therefore, during the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started, the temperature of the piston is less likely to exceed the operating temperature, and the oil jet is less likely to operate. That is, since the cooling of the piston by the oil jet is suppressed, it is possible to suppress the generation of particulate matter due to the temperature of the piston becoming too low.

The schematic diagram which shows the relationship between the control device of an internal combustion engine and an internal combustion engine. A flowchart showing the processing flow of a routine for switching between operation and stop of an oil jet. A timing chart showing the transition of PN when the oil jet is continuously operated even during fuel cut. A flowchart showing the processing flow of the routine for switching the operating temperature. A timing chart showing the transition of PN when the operating temperature is switched and the oil jet is stopped.

Hereinafter, an embodiment of an internal combustion engine control device for controlling an internal combustion engine mounted on a vehicle will be described.
As shown in FIG. 1, the internal combustion engine 10 has a plurality of cylinders 21 (only one is shown in FIG. 1), and the piston 22 reciprocates in each cylinder 21. Each of these pistons 22 is connected to the crank shaft 27 via a connecting rod 26. The area above the piston 22 in the cylinder 21 is the combustion chamber 28. The outer peripheral surface of the piston 22 is formed with a groove for fitting the first compression ring 23, a groove for fitting the second compression ring 24, and a groove for fitting the oil ring 25. In the piston 22, the first compression ring 23, the second compression ring 24, and the oil ring 25 are fitted into these three grooves.

In each combustion chamber 28, an air-fuel mixture containing the intake air introduced through the intake passage 30 and the fuel injected from the fuel injection valve 29 is burned. The exhaust gas generated in each combustion chamber 28 by the combustion of such an air-fuel mixture is discharged to the exhaust passage 40.

Further, the internal combustion engine 10 is provided with an oil supply device 50 that operates to circulate oil in the internal combustion engine 10. The oil supply device 50 includes an oil pump 52 that pumps oil from the inside of the oil pan 51, and an oil jet 53 that injects oil toward the back surface of the piston 22. The oil supply device 50 supplies the oil pumped by the oil pump 52 to each part of the internal combustion engine 10 through the oil supply passage 55. The oil supply passage 55 is provided with a shutoff mechanism 54 for stopping the injection of oil from the oil jet 53 by shutting off the supply of oil to the oil jet 53.

The control device 100, which is a control device for the internal combustion engine 10, has an oil jet control unit 110 that operates a shutoff mechanism 54 to stop the injection of oil from the oil jet 53 or inject oil from the oil jet 53. It is provided.

When the shutoff mechanism 54 is operated so that the oil jet control unit 110 cuts off the supply of oil to the oil jet 53, the oil pumped by the oil pump 52 is still the oil jet 53 even if the oil pump 52 is operating. Will not be supplied to. As a result, oil is no longer injected from the oil jet 53. On the other hand, when the oil jet control unit 110 operates the shutoff mechanism 54 so as not to shut off the supply of oil to the oil jet 53, the oil pumped up by the oil pump 52 is supplied to the oil jet 53. As a result, oil is injected from the oil jet 53 toward the piston 22. That is, in the internal combustion engine 10, the oil jet 53 can be operated or stopped by operating the shutoff mechanism 54 through the oil jet control unit 110 of the control device 100.

Signals from various sensors such as the accelerator position sensor 60 are input to the control device 100 that controls each part of the internal combustion engine 10. The accelerator position sensor 60 detects the opening degree of the accelerator. The crank angle sensor 61 detects the rotation angle of the crank shaft 27. The control device 100 detects the engine rotation speed, which is the rotation speed of the crank shaft 27, based on the rotation angle detected by the crank angle sensor 61. The vehicle speed sensor 62 detects the vehicle speed, which is the speed of the vehicle. The air flow meter 63 detects the amount of intake air, which is the amount of air sucked into the combustion chamber of the internal combustion engine 10. The water temperature sensor 64 detects the temperature of the engine cooling water that cools the internal combustion engine 10.

The control device 100 captures output signals of various sensors, performs various calculations based on the output signals, and performs various operations such as fuel injection control through control of the fuel injection valve 29 according to the calculation results. Take control.

For example, the control device 100 calculates a target fuel injection amount, which is a control target value for the fuel injection amount, based on the opening degree of the accelerator, the engine rotation speed, and the like. Then, the control target values for the injection timing and the fuel injection time are calculated. The fuel injection valve 29 is driven to open in a manner corresponding to these control target values. As a result, an amount of fuel corresponding to the operating state of the internal combustion engine 10 at that time is injected from the fuel injection valve 29 and supplied into each cylinder 21 of the internal combustion engine 10. The control device 100 also implements a fuel cut to reduce the fuel consumption rate by stopping the injection of fuel from the fuel injection valve 29 at the time of deceleration when the opening degree of the accelerator is zero.

Further, in the internal combustion engine 10, the injection of oil from the oil jet 53 is stopped according to the temperature of the piston 22 in order to complete the warming up at an early stage. Such control of the oil jet 53 is executed by the oil jet control unit 110 in the control device 100 as described above.

Next, a series of processes related to the control of the oil jet 53 executed by the oil jet control unit 110 will be described. Switching between operation and stop of the oil jet 53 is specifically realized by the oil jet control unit 110 repeatedly executing the routine shown in FIG. 2 during engine operation.

As shown in FIG. 2, when this routine is started, the oil jet control unit 110 first determines in step S100 whether or not the groove bottom temperature Tor is equal to or higher than the operating temperature Tjet. The groove bottom temperature Tor is the temperature of the bottom of the groove in which the oil ring 25 is fitted.

The oil jet control unit 110 estimates the groove bottom temperature Tor as an index value representing the temperature of the piston 22 during engine operation. Specifically, the oil jet control unit 110 refers to a calculation map that outputs the groove bottom temperature Tor with the engine load calculated from the intake air amount and the engine rotation speed and the engine rotation speed as inputs, and refers to the groove bottom temperature. Estimate Tor. The calculation map is created based on the result of an experiment in which the groove bottom temperature Tor is actually measured by changing the combination of the engine load and the engine rotation speed. Further, there is a difference in the groove bottom temperature Tor between the case where the oil jet 53 is operated and the case where the oil jet 53 is stopped. Therefore, as the calculation map, a calculation map for operation that is referred to when the oil jet 53 is being operated and a calculation map for stoppage that is referred to when the oil jet 53 is stopped are prepared. .. The oil jet control unit 110 switches these calculation maps according to the operating state of the oil jet 53 to estimate the groove bottom temperature Tor. Then, the oil jet control unit 110 calculates, for example, the moving average of the output value of the calculation map as the groove bottom temperature Tor.

The operating temperature Tjet is a value set as a threshold value for determining that it is necessary to stop the injection of oil from the oil jet 53 based on the fact that the groove bottom temperature Tor is lower than the operating temperature Tjet. Therefore, when the oil jet control unit 110 determines in step S100 that the groove bottom temperature Tor is lower than the operating temperature Tjet (step S100: NO), the process proceeds to step S120 to operate the oil jet 53. Stop it. As a result, when the groove bottom temperature Tor is lower than the operating temperature Tjet, for example, when the warming up is not completed, the injection of oil from the oil jet 53 is stopped and the warming up of the internal combustion engine 10 is promoted.

On the other hand, when the oil jet control unit 110 determines in step S100 that the groove bottom temperature Tor is equal to or higher than the operating temperature Tjet (step S100: YES), the process proceeds to step S110. Then, the oil jet 53 is operated. As a result, the piston 22 is cooled by the oil injected from the oil jet 53, and for example, the piston 22 is prevented from being seized.

When the oil jet control unit 110 executes the process of step S110 or the process of step S120, the oil jet control unit 110 temporarily ends this routine. In this way, in the internal combustion engine 10, the operation and stop of the oil jet 53 are switched by the oil jet control unit 110 according to the groove bottom temperature Tor estimated as an index value representing the temperature of the piston 22. The oil jet control unit 110 in the control device 100 does not immediately stop the oil jet 53 when the groove bottom temperature Tor drops from a state where the operating temperature Tor is above the operating temperature Tjet to below the operating temperature Tjet. The oil jet 53 is stopped after the state where the bottom temperature Tor is lower than the operating temperature Tjet continues for a certain period of time. This is because when the oil jet 53 is stopped immediately based on the fact that the groove bottom temperature Tor becomes lower than the operating temperature Tjet, the groove bottom temperature Tor immediately starts to rise as the oil jet 53 is stopped, and the operating temperature is increased. This is because there is a possibility that the oil jet 53 will be stopped and operated repeatedly in a very short cycle when the temperature exceeds Tjet.

By the way, if the temperature of the piston 22 is excessively low, particulate matter is likely to be generated as the fuel burns. Therefore, if the oil jet 53 is operated until the temperature of the piston 22 tends to drop, such as when fuel cut is being executed, the temperature of the piston 22 drops excessively and fuel injection is restarted. There is a risk that particulate matter will be generated when this is done.

FIG. 3 is a timing chart showing the transition of the groove bottom temperature Tor and the transition of the cumulative amount of particulate matter PN when the operation of the oil jet 53 is continued even while the fuel cut is being executed. be.

In the example shown in FIG. 3, the operating temperature Tjet is set to the first temperature T1. As shown in FIG. 3, the fuel cut flag is turned off before the time t10, the fuel cut is not performed, and the fuel injection is executed. Since the groove bottom temperature Tor at this time is equal to or higher than the operating temperature Tjet, the oil jet 53 is operating.

At time t10, when the fuel cut execution condition is satisfied and the fuel cut flag is turned ON, the fuel injection is stopped and the fuel cut is executed. Then, the fuel is not burned in the combustion chamber 28. Even at this time, since the groove bottom temperature Tor is equal to or higher than the operating temperature Tjet, the operation of the oil jet 53 is continued. As a result, the groove bottom temperature Tor gradually decreases.

Then, when the fuel cut execution condition is not satisfied and the fuel cut flag is turned off at time t20, the fuel injection is restarted and the combustion of the fuel in the combustion chamber 28 is restarted. At this time, the temperature of the piston 22 is low. Therefore, the fuel injected from the fuel injection valve 29 adheres to the top surface of the piston 22 and tends to be dropleted, and particulate matter is likely to be generated as the combustion resumes. As a result, immediately after the restart of fuel injection, the cumulative amount of particulate matter PN increases.

As described above, if the temperature of the piston 22 becomes too low, particulate matter may be generated. Therefore, in the control device 100, the cooling suppression condition is an operating condition in which the temperature of the piston 22 drops too much when the oil jet 53 is operated so that particulate matter is likely to be generated. When the cooling suppression condition is satisfied, the operating temperature Tjet is set to a higher value than when the cooling suppression condition is not satisfied, so that the operation of the oil jet 53 is suppressed.

Such switching of the operating temperature Tjet is performed by the oil jet control unit 110 during engine operation. Specifically, the oil jet control unit 110 repeatedly executes the routine shown in FIG. 4 together with the routine described with reference to FIG. 3 during engine operation.

As shown in FIG. 4, when this routine is started, the oil jet control unit 110 determines in step S200 whether or not the cooling suppression condition is satisfied. In this control device 100, the following logical sum conditions (A) and (B) are set as cooling suppression conditions.

(A) Between the start of fuel cut and the restart of fuel injection until the lapse of a predetermined period.
(B) Between the start of the engine and the elapse of the prescribed period.

In (A), the period until the integrated air amount, which is the integrated value of the intake air amount after restarting the fuel injection, reaches a predetermined constant value, for example, the determined air amount GA1, is set as a predetermined period. There is. Further, in (B), a predetermined period is set from the start of the engine until a certain time elapses.

If it is determined in step S200 that the cooling suppression condition is not satisfied (step S200: NO), that is, if none of the above (A) and (B) is applicable, the oil jet control unit 110 , The process proceeds to step S220.

Then, the oil jet control unit 110 selects the first temperature T1 as the temperature to be adopted for the operating temperature Tjet in step S220. The first temperature T1 needs to stop the injection of oil from the oil jet 53 in order to complete the warming up of the internal combustion engine 10 at an early stage based on, for example, that the groove bottom temperature Tor is lower than the first temperature T1. Is set as a threshold value for determining. That is, the first temperature T1 is set as an upper limit value in the range of the groove bottom temperature Tor that stops the oil jet 53 in order to promote the warming up of the internal combustion engine 10.

On the other hand, when the oil jet control unit 110 determines in step S200 that the cooling suppression condition is satisfied (step S200: YES), that is, when any of the above (A) and (B) is applicable. Alternatively, if both are applicable, the process proceeds to step S210.

Then, the oil jet control unit 110 selects the second temperature T2 as the temperature to be adopted for the operating temperature Tjet in step S210. The second temperature T2 is a temperature higher than the first temperature T1. Further, the second temperature T2 is based on the fact that the groove bottom temperature Tor has reached the second temperature T2, and if the oil jet 53 is continuously stopped, there is a high possibility that the temperature of the piston becomes higher as the piston 22 seizes. It is set as a threshold value for determining. That is, the second temperature T2 is set as the upper limit value of the groove bottom temperature Tor that can continue the stop of the oil jet 53. When the oil jet control unit 110 executes the process of step S210 or the process of step S220, the oil jet control unit 110 temporarily ends this routine.

Next, the operation of this embodiment will be described with reference to FIG. As described with reference to the flowchart shown in FIG. 4, in the internal combustion engine 10, the operating temperature Tjet is switched depending on whether or not the cooling suppression condition is satisfied. Specifically, the operating temperature Tjet is set to the first temperature T1 during the period from the start of the fuel cut to the time when the fuel injection is restarted and the predetermined period elapses and from the engine start until the predetermined period elapses. It is switched to a higher second temperature T2. That is, the first temperature T1 which is the operating temperature Tjet when the fuel cut is restarted and the fuel injection is restarted until the predetermined period elapses, or between the engine start and the elapse of the predetermined period. In comparison, the operating temperature Tjet is increased.

FIG. 5 shows a case where the operation of the oil jet 53 is controlled through the routine described with reference to FIG. 2 and the routine described with reference to FIG. 4 under the same conditions as those described with reference to FIG. The transition of the operation status of the oil jet 53 and the transition of the cumulative amount of particulate matter PN are shown. That is, FIG. 5 shows a transition of the operation status of the oil jet 53 when the oil jet 53 is controlled through the oil jet control unit 110 in the control device 100 of the present embodiment, and a transition of the cumulative amount of particulate matter PN. Is shown.

As shown in FIG. 5, the operating temperature Tjet is set to the first temperature T1 before the time t10. Then, before the time t10, the fuel cut flag is turned off, the fuel cut is not performed, and the fuel injection is executed. Since the groove bottom temperature Tor at this time is equal to or higher than the operating temperature Tjet, the oil jet 53 is operating.

At time t10, when the fuel cut execution condition is satisfied and the fuel cut flag is turned ON, the fuel injection is stopped and the fuel cut is executed. Then, it is determined that the cooling suppression condition is satisfied, and the operating temperature Tjet is switched to the second temperature T2. As a result, the groove bottom temperature Tor becomes less than the operating temperature Tjet. The control device 100 integrates the intake air amount while the fuel injection is being executed and calculates the integrated air amount, but when the fuel cut is executed, the integrated air amount is reset to "0". ..

Then, the oil jet control unit 110 stops the oil jet 53 at a time t11 in which the state where the groove bottom temperature Tor is lower than the operating temperature Tjet continues for a certain period of time. When the oil jet 53 is stopped in this way, the cooling action of the oil injected from the oil jet 53 disappears, so that the groove bottom temperature Tor is less likely to decrease as compared with the case shown in FIG.

Then, when the fuel cut execution condition is not satisfied and the fuel cut flag is turned off at time t20, the fuel injection is restarted and the combustion of the fuel in the combustion chamber 28 is restarted. Since the injection of oil from the oil jet 53 was stopped, the groove bottom temperature Tor at this time was maintained at a higher state than in the case shown in FIG. Therefore, it is difficult for the fuel injected from the fuel injection valve 29 to form droplets, and it is difficult for particulate matter to be generated. As a result, the cumulative amount of particulate matter PN does not increase even immediately after restarting fuel injection.

When fuel injection is restarted at time t20, the groove bottom temperature Tor begins to rise. In addition, the integration of the intake air amount is started, and the integrated air amount increases. When the integrated air amount reaches the determined air amount GA1 at time t21, the cooling suppression condition is not satisfied, and the operating temperature Tjet is switched to the first temperature T1. As a result, the groove bottom temperature Tor becomes equal to or higher than the operating temperature Tfet, and the oil jet 53 operates again.

As described above, according to the control device 100 of the present embodiment, the oil jet 53 is stopped when the cooling suppression condition is satisfied, that is, during the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started.

The effect of this embodiment will be described.
(1) During fuel cut, immediately after restarting fuel injection, and immediately after starting the engine, if the oil jet 53 is operated, the piston 22 may become too cold and the temperature may become too low. As a result, particulate matter is likely to be generated as the fuel burns. On the other hand, in the control device 100, the operating temperature Tjet is raised during the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started. Therefore, during the fuel cut, immediately after the restart of fuel injection, and immediately after the engine is started, the groove bottom temperature Tor is less likely to exceed the operating temperature Tjet, and the oil jet 53 is less likely to operate. That is, since the cooling of the piston 22 by the oil jet 53 is suppressed, it is possible to suppress the generation of particulate matter due to the temperature of the piston 22 becoming too low.

(2) Since the injection of oil from the oil jet 53 is suppressed, the amount of oil sucked up into the combustion chamber 28 is also reduced. As a result, it is possible to suppress the generation of particulate matter due to the combustion of oil.

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.
Although the configuration for estimating the groove bottom temperature Tor is exemplified as an index value representing the temperature of the piston 22, the method for estimating the temperature of the piston 22 can be appropriately changed. For example, the temperature of the top surface of the piston 22 or the temperature of the bottom of the groove into which the first compression ring 23 is fitted may be estimated as an index value representing the temperature of the piston 22.

10 ... Internal combustion engine, 21 ... Cylinder, 22 ... Piston, 23 ... 1st compression ring, 24 ... 2nd compression ring, 25 ... Oil ring, 26 ... Connecting rod, 27 ... Crank shaft, 28 ... Combustion chamber, 29 ... Fuel Injection valve, 30 ... intake passage, 40 ... exhaust passage, 50 ... oil supply device, 51 ... oil pan, 52 ... oil pump, 53 ... oil jet, 54 ... shutoff mechanism, 60 ... accelerator position sensor, 61 ... crank angle sensor , 62 ... Vehicle speed sensor, 63 ... Air flow meter, 64 ... Water temperature sensor, 100 ... Control device, 110 ... Oil jet control unit.

Claims (1)

An oil jet that injects oil toward the piston,
It is applied to an internal combustion engine provided with a shutoff mechanism that shuts off the supply of oil to the oil jet and stops the injection of oil from the oil jet.
Provided is an oil jet control unit that shuts off the supply of oil to the oil jet and stops the injection of oil from the oil jet by operating the shutoff mechanism when the temperature of the piston is lower than the operating temperature. It is a control device for internal combustion engines.
The oil jet control unit starts the fuel cut to stop the fuel injection until the fuel injection is restarted until a predetermined period elapses, and from the engine start until the predetermined period elapses. It is recommended to raise the operating temperature as compared with the case where the fuel injection is restarted after the cut is started and the predetermined period is not elapsed, or the engine is started and the predetermined period is not elapsed. A characteristic internal combustion engine control device.

Images