JP2019190296A - Control device of internal combustion engine - Google Patents

Abstract

To provide a control device of an internal combustion engine which can effectively suppress the accumulation of deposits in a piston.SOLUTION: In a control device of an internal combustion engine for stopping oil injection when a rotational speed and a load rate of the internal combustion engine mounted to a vehicle belong to a stop region for stopping the oil injection to a piston from an oil jet, when a maximum value of an altitude difference in a traveling path in which a traveling frequency of the vehicle is high is equal to a threshold or larger, and when the fact that a vehicle speed of the vehicle belongs within a prescribed range, and an operation state of the internal combustion engine belongs to a prescribed high-rotation low-load region arises a prescribed number of times within a prescribed period, the stop region is expanded in an order of high-rotational speeds of the internal combustion engine.SELECTED DRAWING: Figure 3

Description

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

  Patent Document 1 discloses a technique for executing or stopping oil injection from an oil jet to a piston in accordance with the temperature of the piston and the fuel injection amount in order to suppress deposit accumulation in the piston.

JP 2017-145757 A

  It has been found that such deposits cause the deposits to grow and the deposition amount to increase by repeatedly performing a predetermined running state. In the said patent document 1, since such a viewpoint is not considered, there exists a possibility that deposit accumulation cannot be suppressed effectively.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can effectively suppress deposit accumulation on a piston.

  An object of the present invention is to provide a control device for an internal combustion engine that stops oil injection when the rotational speed and load factor of the internal combustion engine mounted on the vehicle belong to a stop region where oil injection from an oil jet to a piston stops. The maximum value of the altitude difference in a travel route with a high travel frequency is equal to or greater than a threshold value, and the vehicle speed of the vehicle belongs to a predetermined range, and the operation state of the internal combustion engine belongs to a predetermined high rotation / low load region. When the predetermined number of times is exceeded within a predetermined period, it can be achieved by an internal combustion engine control device that expands the stop region to a higher rotational speed of the internal combustion engine.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can suppress effectively the deposit accumulation in a piston can be provided.

FIG. 1 is a diagram showing an engine to which the control device of this embodiment is applied. FIG. 2 is an example of a map showing an oil injection stop area where oil injection is stopped and an oil injection execution area where oil injection is executed. FIG. 3 is a flowchart showing an example of control executed by the ECU.

  FIG. 1 is a diagram showing an engine 20 to which the control device of this embodiment is applied. The engine 20 is an example of an internal combustion engine, and burns an air-fuel mixture in a combustion chamber 23 in a cylinder head 22 installed on a cylinder block 21 in which the piston 24 is housed, thereby causing the piston 24 to reciprocate. The reciprocating motion of the piston 24 is converted into the rotational motion of the crankshaft 26. An oil pan 21 a that stores lubricating oil is provided below the cylinder block 21. Although not shown, the engine 20 is an in-line four-cylinder engine having four cylinders, but is not limited to this. The engine 20 is mounted on the vehicle as a travel source.

  The cylinder head 22 of the engine 20 is provided with an intake valve 42 for opening and closing the intake port 10i and an exhaust valve 44 for opening and closing the exhaust port 30e for each cylinder. An ignition plug 27 for igniting the air-fuel mixture in the combustion chamber 23 is attached to the top of the cylinder head 22 for each cylinder.

  The intake port 10i of each cylinder is connected to the surge tank 18 via a branch pipe for each cylinder. An intake pipe 10 is connected to the upstream side of the surge tank 18, and an air cleaner 19 is provided at the upstream end of the intake pipe 10. The intake pipe 10 is provided with an air flow meter 15 for detecting the intake air amount and an electronically controlled throttle valve 13 in order from the upstream side.

  Further, a port injection valve 12 for injecting fuel into the intake port 10i is installed in the intake port 10i of each cylinder. The fuel injected from the port injection valve 12 is mixed with intake air to form an air-fuel mixture, which is sucked into the combustion chamber 23 when the intake valve 42 is opened, compressed by the piston 24, and ignited by the spark plug 27. Burned.

  The exhaust port 30e of each cylinder is connected to the exhaust pipe 30 via a branch pipe for each cylinder. A three-way catalyst 31 is provided in the exhaust pipe 30. An air-fuel ratio sensor 33 for detecting the air-fuel ratio of the exhaust gas is installed on the upstream side of the three-way catalyst 31.

  An oil jet 53 for injecting oil in the oil pan 21 a to the back side of the piston 24 is provided. From the oil jet 53, the oil sucked by the oil pump 50 is injected through the oil strainer 51. A control valve 52 is provided between the oil pump 50 and the oil jet 53, and the amount of oil injected from the oil jet 53 is adjusted according to the opening degree of the control valve 52. When the oil is injected from the oil jet 53 to the piston 24, the temperature of the piston 24 is lowered. As will be described in detail later, when the operating state of the engine 20 belongs to a predetermined region, the oil injection is stopped by fully closing the control valve 52.

  The ECU (Electronic Control Unit) 60 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The ECU 60 controls the engine 20 by executing a program stored in the RAM or ROM. The ECU 60 is a control device for the engine 20.

  The ECU 60 is electrically connected to the ignition plug 27, the throttle valve 13, and the port injection valve 12 described above. The ECU 60 also includes an accelerator opening sensor 11 that detects the accelerator opening, a throttle opening sensor 14 that detects the throttle opening of the throttle valve 13, an air flow meter 15 that detects the intake air amount, an air-fuel ratio sensor 33, a crankshaft. The crank angle sensor 25 for detecting the crank angle 26, the water temperature sensor 29 for detecting the temperature of the cooling water of the engine 20, the control valve 52 described above, and other various sensors are electrically connected. The ECU 60 controls the ignition plug 27, the throttle valve 13, the port injection valve 12, and the like so as to obtain a desired output based on the detection values of various sensors, and the like, and the ignition timing, fuel injection amount, fuel injection timing, Control the throttle opening.

  The storage device of the navigation device 90 is mounted on a vehicle on which the engine 20 is mounted, and stores map data, past travel history of the vehicle 1, and the like. The navigation device 90 has a built-in GPS (Global Positioning System) receiver that acquires position information of the vehicle 1. The ECU 60 is electrically connected to the navigation device 90.

  Here, deposits may accumulate on the top surface of the piston 24 due to oil injection from the oil jet 53 to the piston 24. For example, when the operating state of the engine 20 is low rotation and low load, the pressure in the combustion chamber 23 is lower than the pressure in the oil pan 21a due to the relatively small throttle opening, so that the oil flows into the combustion chamber 23. The temperature of the piston 24 is likely to be lowered. For this reason, when the driving | running state of the engine 20 is a low rotation low load, it is easy to generate a deposit. When the operating state of the engine 20 is low rotation and low load, the ECU 60 stops oil injection from the oil jet 53.

  FIG. 2 is an example of a map showing an oil injection stop area where oil injection is stopped and an oil injection execution area where oil injection is executed. In FIG. 2, the horizontal axis indicates the rotational speed [rpm] of the engine 20, and the vertical axis indicates the load factor [%] of the engine 20. The oil injection stop region is set to an operation region where the piston 24 is not so hot that cooling with oil is necessary. For example, the upper limit value of the rotation speed in the oil injection stop region is set to 3000 rpm. In this way, the oil injection is stopped in the operation region where deposits are likely to occur, so that the generation of deposits is suppressed.

  However, even if the oil injection stop region is set as described above, the deposit is caused to occur on the piston 24 because the running state in which the operating state of the engine 20 becomes a high rotation and low load is frequently repeated within a predetermined period. It has been found that the amount of deposit deposition increases. Therefore, when such a predetermined traveling state is repeated, the ECU 60 of this embodiment suppresses deposit accumulation by expanding the oil injection stop region so as to include high rotation and low load. Below, the control which changes an oil injection stop area | region is demonstrated.

  FIG. 3 is a flowchart illustrating an example of control executed by the ECU 60. First, based on the information stored in the navigation device 90, it is determined whether or not the maximum altitude difference, which is the maximum value of the altitude difference on the travel route where the vehicle travels frequently, is greater than or equal to a threshold value H. (Step S1). The navigation device 90 stores registered home location information, information on travel routes with high travel frequency, and map data including altitude. Based on these pieces of information, the ECU 60 calculates an elevation difference on a traveling route with a high traveling frequency, and obtains the maximum elevation difference.

  When traveling on a route with a large difference in altitude, the acceleration and deceleration of the vehicle tend to be gentle, and when going down a slope, for example, the vehicle speed tends to rise even if the accelerator opening is small. That is, when traveling on a route with a large difference in elevation, it can be considered that the operating state of the engine 20 tends to be a high rotation and low load. If the determination in step S1 is negative, this control ends.

  If the determination in step S1 is affirmative, it is determined whether or not the traveling time of the vehicle is included between 10:00 PM and 7:00 AM (step S3). The traveling time of the vehicle is stored in the navigation device 90, and the ECU 60 acquires and determines information stored in the navigation device 90. When the traveling time of the vehicle is included between 10:00 PM and 7:00 AM, it can be considered that the vehicle has traveled in an environment where the outside air temperature is relatively low. In addition, said time slot | zone is an example to the last, and is not limited to this.

  When the vehicle travels in an environment where the outside air temperature is relatively low, the temperature of the intake air introduced into the combustion chamber 23 is also relatively low. Therefore, the temperature in the combustion chamber 23 is likely to decrease, and deposits are likely to accumulate. If a negative determination is made in step S3, this control ends. If the determination in step S3 is affirmative, the first flag is turned on (step S5).

  Next, it is determined whether the vehicle speed is equal to or higher than the threshold value V, the rotational speed of the engine 20 is equal to or higher than the threshold value R, and the load factor of the engine 20 is lower than the threshold value K for 15 seconds or longer. (Step S7). The vehicle speed is acquired based on a vehicle speed sensor mounted on the vehicle, the rotational speed of the engine 20 is acquired based on the crank angle sensor 25, and the load factor of the engine 20 is acquired based on the air flow meter 15. For example, the threshold value V is 70 Km / h, the threshold value R is 3000 rpm, and the threshold value K is 15%. The process of step S7 is executed for each trip. The above threshold values and the period of 15 seconds are merely examples, and are not limited thereto.

  When the vehicle speed is equal to or higher than the threshold value V, it can be considered that the vehicle is in a traveling state that is not in an idle state. In this traveling state, when the rotational speed of the engine 20 is equal to or higher than the threshold value R and the load factor is less than the threshold value K, the operating state of the engine 20 is considered to be a high rotational speed and a low load, and the traveling state in which the deposit can grow. It can be regarded as being. By continuing this running state for 15 seconds or more, it can be regarded as a running state in which deposits can grow and the deposition amount can increase.

  If the determination in step S7 is negative, step S11 described later is executed. If the determination in step S7 is affirmative, the second flag is turned on (step S9).

  After step S9 is executed or after a negative determination is made in step S7, it is determined whether or not two weeks have passed since the previous determination of whether or not the oil injection stop region has been changed (step S11). The two weeks are merely an example, and the present invention is not limited to this. Step S11 will be described later.

  If a negative determination is made in step S11, this control ends. If the determination in step S11 is affirmative, the number of times A that the first flag has been turned on and the number of times B that the second flag has been turned on in the most recent past month are counted (step S13). Next, it is determined whether or not the number of times A is greater than or equal to the threshold value α and the number of times B is greater than or equal to the threshold value β (step S15). The threshold values α and β are both 90 times, for example, but are not limited thereto, and the threshold values α and β may be different values. One month is merely an example, and the present invention is not limited to this.

  If the determination in step S15 is affirmative, the oil injection stop region is expanded (step S17). Specifically, the upper limit value of the rotation speed in the oil injection stop region is changed from the initial value of 3000 rpm to the higher value of 4000 rpm as shown in FIG. Thereby, when the high rotation and low load is included in the oil injection stop region and the operation state of the engine 20 belongs to the high rotation and low load region, the oil injection is stopped, so that deposit accumulation can be effectively suppressed. Note that the initial value of the upper limit value of the rotational speed in the oil injection stop region and the upper limit value after enlargement are merely examples, and are not limited thereto.

  If a negative determination is made in step S15, it is determined whether or not the oil injection stop region has been expanded (step S19). If the determination in step S19 is affirmative, the oil injection stop region is reduced (step S21). In the case of an affirmative determination in step S19, the oil injection stop region was expanded last time, but this time, it is considered that the frequency of the driving state in which the operating state of the engine 20 is high rotation and low load is low, and the oil injection stop This is because there is no need to keep the area expanded. For example, the upper limit value of the oil injection stop region is changed from 4000 rpm to the initial value of 3000 rpm.

  If the determination in step S19 is negative, this control ends. In this case, although the altitude difference in the travel route of the vehicle is large, it is considered that the frequency of the travel state in which the operating state of the engine 20 is high rotation and low load is low, and there is no need to expand the oil injection stop region. It is.

  As described above, when it is determined that the traveling state in which the deposit grows and the amount of accumulation tends to increase is frequently repeated, the oil injection stop region is expanded, and deposit accumulation is suppressed. In addition, step S11 described above is performed after two weeks have passed since the oil injection stop region has been changed, and the oil injection stop region is prevented from being frequently changed.

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

  In the above-described embodiment, the route from which the ECU 60 acquires the elevation difference on the travel route with high travel frequency is not limited to the information from the navigation device 90. For example, information indicating the current position of a vehicle is constantly transmitted to a server installed outside the vehicle, and this server travels frequently with the vehicle, the altitude difference within the travel route, and the altitude difference. May be transmitted to the ECU 60, and the ECU 60 may acquire the maximum elevation difference based on this information.

  The time zone of step S3 may differ depending on the region and season. Further, in place of step S3, the first flag may be turned ON when the deposit is in a predetermined season or a predetermined region where deposits are likely to accumulate. Instead of step S3, temperature information within the travel time around the travel route is acquired, and the first flag may be turned on when the average temperature during this travel time is included in a predetermined range. The temperature information may be, for example, an outside air temperature acquired from a temperature sensor mounted on the vehicle, or may be temperature information acquired from weather information or the like. Step S3 is not always necessary. This is because, depending on the type of engine, the outside air temperature at the travel time may hardly affect the deposit accumulation.

  The extent to which the oil injection stop area is expanded may be set according to the above-described number of times A and B. For example, when the number of times A and B is 50 times or more and less than 90 times, the upper limit value of the rotation speed of the oil injection stop region is increased from the initial value of 3000 rpm to 3500 rpm, and the number of times A and B is 90 times or more, respectively. In this case, the upper limit value may be increased from the initial value of 3000 rpm to 4000 rpm. The same applies when the oil injection stop region is reduced.

  Further, the expansion of the oil injection stop region may be executed in stages. For example, when the oil injection stop region is expanded for the first time, the upper limit value is increased from the initial value of 3000 rpm to 3500 rpm, and when the oil injection stop region is expanded again thereafter, the upper limit value is increased from 3500 rpm to 4000 rpm. May be. The same applies when the oil injection stop region is reduced.

20 engine (internal combustion engine)
23 Combustion chamber 24 Piston 60 ECU (control device for internal combustion engine)
90 Navigation device

Claims (1)

In a control device for an internal combustion engine that stops oil injection when the rotational speed and load factor of the internal combustion engine mounted on the vehicle belong to a stop region in which oil injection from the oil jet to the piston stops.
The maximum value of the altitude difference in the travel route where the vehicle travels frequently is greater than or equal to a threshold value, and the vehicle speed of the vehicle belongs to a predetermined range, and the operating state of the internal combustion engine belongs to a predetermined high rotation / low load region The control device for the internal combustion engine expands the stop region to a higher rotational speed side of the internal combustion engine when the predetermined number of times is exceeded within a predetermined period.

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