JP2019124138A - Controller of internal combustion engine - Google Patents

Abstract

To provide a controller of an internal combustion engine capable of suppressing occurrence of deposit in an ejector.SOLUTION: A CPU 62 is configured to sequentially calculate a cumulative time at which a downstream side pressure Pd becomes a predetermined value or more, and store it in a non-volatile memory 66. The CPU 62 is configured to, when the cumulative time is equal to or less than a predetermined time in a predetermined period, reduce opening of a WGV 32, and increase the downstream pressure of a compressor wheel 14a. Also the CPU 62 is configured to reduce opening of a throttle valve 16 following the pressure increase processing.SELECTED DRAWING: Figure 1

Description

  The present invention comprises a supercharger, an adjusting device for adjusting an exhaust amount of the exhaust gas discharged to the exhaust passage to be blown to a turbine wheel of the supercharger, and a downstream side and an upstream side of a compressor wheel of the supercharger. And a control device for an internal combustion engine applied to an internal combustion engine, wherein the suction portion of the ejector is connected to a crankcase.

  For example, Patent Document 1 listed below describes an apparatus for sucking blowby gas in a crankcase by an ejector and causing the blowby gas to flow out to the upstream side of a turbocharger in an intake passage.

JP, 2013-124544, A

  As described above, when using the ejector, if the pressure at the downstream side of the turbocharger is not sufficiently higher than the pressure at the upstream side, it flows into the ejector from the downstream side of the turbine wheel in the intake passage. Frequency of air flow is low. In that case, deposits may be deposited on the ejector due to oil mist or particulate matter in the blowby gas, and the cross-sectional area of the flow path in the ejector may be reduced, that is, so-called clogging may occur.

  In order to solve the above problems, a control device for an internal combustion engine comprises: a supercharger; an adjusting device for adjusting an amount of exhaust gas discharged to an exhaust passage to be blown to a turbine wheel of the supercharger; And an ejector connecting the downstream side and the upstream side of the compressor wheel of the engine, the suction portion of the ejector being applied to an internal combustion engine connected to the crankcase, and the pressure on the downstream side of the turbine wheel is a predetermined value If the cumulative time of the state which becomes equal to or more than the predetermined value in the predetermined period is less than or equal to the predetermined time based on the storing process of storing the history of the above state and the stored history, the adjusting device is operated And raising the pressure on the downstream side.

  In the above configuration, when the cumulative time of the state in which the predetermined value is equal to or more than the predetermined value in the predetermined period is equal to or less than the predetermined time, the pressure on the downstream side of the turbocharger is less frequently higher than the pressure on the upstream side. Due to oil mist or particulate matter in the gas, deposits may be deposited on the ejector, resulting in a so-called blockage in which the flow passage cross-sectional area in the ejector is reduced. Therefore, in the above configuration, when there is such a risk, the pressure on the downstream side is increased. Thus, the amount of air flowing into the ejector from the downstream side of the turbine wheel in the intake passage can be increased. And thereby, the oil etc. which retain in an ejector are blown off, and it can suppress that a deposit arises.

FIG. 1 shows a control device and an internal combustion engine according to one embodiment. The figure which shows the ventilation method of the crankcase concerning the embodiment. FIG. 3 is a block diagram showing processing executed by the control device according to the embodiment.

Hereinafter, an embodiment according to a control device for an internal combustion engine will be described with reference to the drawings.
An internal combustion engine 10 shown in FIG. 1 is an on-vehicle motor. The air taken in from the intake passage 12 of the internal combustion engine 10 flows into the combustion chamber 24 defined by the cylinder 20 and the piston 22 via the compressor wheel 14 a of the turbocharger 14 and the throttle valve 16. A mixture of air flowing into the combustion chamber 24 and a fuel such as gasoline is provided for combustion by spark discharge by an ignition device (not shown), and the mixture provided for combustion is discharged to the exhaust passage 30 as exhaust gas. . The exhaust passage 30 is provided with a bypass passage 32 bypassing the turbine wheel 14 b of the turbocharger 14 and a waste gate valve (WGV 34) adjusting the flow passage cross-sectional area of the bypass passage 32.

  A crankcase 28 is divided by the cylinder 20 and the oil pan 26. A portion of the intake passage 12 upstream of the turbocharger 14 is connected to the crankcase 28 by the air introduction passage 40. In addition, the crankcase 28 is a blowby gas through an oil separator 42 that separates the oil in the blowby gas including unburned fuel and oil mist that has flowed into the crankcase 28 through the sliding surfaces with the cylinder 20 and the piston 22. Is connected to the discharge passage 44 of the The discharge passage 44 is connected to a portion of the intake passage 12 downstream of the throttle valve 16 via the PCV passage 46. Further, the PCV passage 46 is provided with a PCV valve 48 which opens on the condition that the pressure downstream of the throttle valve 16 in the intake passage 12 is lower than the atmospheric pressure.

  A bypass passage 50 bypassing the compressor wheel 14 a of the turbocharger 14 is connected to the intake passage 12. The bypass passage 50 includes an upstream passage 52, an ejector 54 and a downstream passage 56. When the intake air flows out from the upstream side passage 52 to the downstream side passage 56, the ejector 54 generates a negative pressure, and sucks the blover gas that has flowed from the crankcase 28 into the discharge passage 44 from the suction portion 54a.

  Thus, in the present embodiment, as ventilation processing for discharging the blowby gas into the intake passage 12, processing for discharging the intake passage 12 via the PCV valve 48, and processing for discharging the intake passage 12 via the ejector 54 Is executed.

  FIG. 2 shows a natural intake ventilation area for discharging the blowby gas into the intake passage 12 via the PCV valve 48 and a supercharging area ventilation area for discharging the blowby gas into the intake passage 12 via the ejector 54. In FIG. 2, the horizontal axis is the pressure downstream of the throttle valve 16 (hereinafter referred to as intake manifold pressure). As shown in FIG. 2, the region where the intake manifold pressure is low is a natural intake ventilation region, and the region where the intake manifold pressure is high is a supercharged region ventilation region.

  Returning to FIG. 1, the control device 60 controls the internal combustion engine 10 and operates the operation part of the internal combustion engine 10 such as the throttle valve 16 and the WGV 34 in order to control the torque and the exhaust component etc. . At that time, the control device 60 is detected by the upstream pressure Pu which is the pressure on the upstream side of the throttle valve 16 in the intake passage 12 and the downstream pressure sensor 72 which are detected by the upstream pressure sensor 70. The downstream pressure Pd, which is the pressure downstream of the throttle valve 16 in the intake passage 12, is referred to. Further, the control device 60 refers to the output signal Scr of the crank sensor 74 and the depression amount of the accelerator pedal (acceleration operation amount ACCP) detected by the accelerator sensor 76. The control device 60 includes a CPU 62, a ROM 64, and an electrically rewritable non-volatile memory 66. The CPU 62 executes the program stored in the ROM 64 to realize the control of the control amount.

FIG. 3 shows a part of the processing executed by the control device 60. The process shown in FIG. 3 is realized by the CPU 62 executing a program stored in the ROM 64.
The required torque calculation process M10 is a process for calculating the required torque Trq * to a larger value when the accelerator operation amount ACCP is large than when it is small. The target load factor calculation process M12 is a process for calculating a target load factor KL * that is a target value of the load factor KL for realizing the required torque Trq *. Incidentally, the load factor KL is a ratio of the amount of inflowing air per one combustion cycle of one cylinder to the reference amount of inflowing air, and it quantifies the amount of in-cylinder charging air. In the present embodiment, the reference inflow air amount is the in-cylinder filling air amount when the opening degree of the throttle valve 16 reaches the maximum value, assuming that the compressor wheel 14a does not perform supercharging. The reference inflow air amount may be variably set according to the rotational speed NE.

  The target boost pressure calculation process M14 is a process of calculating the target boost pressure Pa * to a larger value when the target load factor KL * is larger than when it is smaller. Specifically, when the predetermined value is set to a value slightly smaller than "1", the target boost pressure calculation process M14 sets the target boost pressure Pa * to the atmospheric pressure when the target load factor KL * is equal to or higher than the predetermined value. It is a process to set to a higher value.

  The feedback processing M18 is a target that is a target value of the opening degree θw of the WGV 34 as an operation amount for performing feedback control of the upstream pressure Pu as the supercharging pressure to the target supercharging pressure Pa * corrected by the correction process M16. This is a process of calculating the opening degree θw *. The WGV operation process M19 is a process of operating the WGV 34 by outputting the operation signal MS2 to the WGV 34 so that the opening degree θw of the WGV 34 becomes the target opening degree θw *.

  The target throttle opening degree calculation process M20 is a target value of the opening degree θs of the throttle valve 16 based on the rotational speed NE, the target boost pressure Pa * corrected by the correction process M16, and the target load factor KL *. This is processing to calculate the target opening degree θs *. Specifically, the target throttle opening degree calculation process M20 is a process for calculating the target opening degree θs * to a larger value than when the target load factor KL * is large. Further, the target throttle opening degree calculation process M20 is a process for calculating the target opening degree θs * to a smaller value when the target load factor KL * is the same, than when the target boost pressure Pa * is large. .

  The throttle operation processing M22 is processing for outputting the operation signal MS1 to the throttle valve 16 to operate the opening degree θs of the throttle valve 16 so that the opening degree θs of the throttle valve 16 becomes the target opening degree θs *.

  The storage processing M24 sequentially determines whether the downstream pressure Pd is equal to or higher than the predetermined value or lower than the predetermined value, calculates the accumulated time equal to or greater than the predetermined value in the predetermined period, and stores the accumulated time in the non-volatile memory 66 Also, it is a process of updating the stored cumulative time. Here, the predetermined value is set to a value higher than the atmospheric pressure.

  In the raising process M26, when the accumulated time in the predetermined period is equal to or less than the predetermined time, the correction amount ΔP for increasing and correcting the target boost pressure Pa * is set to a value larger than zero during the time having the prescribed length. It is a process to calculate. The correction process M16 is a process of correcting the target boost pressure Pa * calculated by the target boost pressure calculation process M14 with the correction amount ΔP. Note that, normally, the correction amount ΔP is set to zero, and the target boost pressure Pa * calculated by the target boost pressure calculation process M14 is directly input to the feedback process M18.

Here, the operation and effects of the present embodiment will be described.
The CPU 62 sequentially calculates the cumulative time when the downstream pressure Pd is equal to or higher than the predetermined value by the storage process M24, and updates the value in the non-volatile memory 66. Then, when the accumulated time in the predetermined period is equal to or less than the predetermined time, the CPU 62 increases and corrects the target boost pressure Pa * by the correction amount ΔP by the increase processing M26. Thus, the CPU 62 reduces the target opening degree θw * so as to feedback control the upstream pressure Pu to the target boost pressure Pa * by the feedback processing M18, and reduces the opening degree θw of the WGV 34 by the WGV operation processing M19. The WGV 34 is operated to control the target opening degree θw *. As a result, it is possible to increase the degree to which the pressure on the upstream side of the compressor wheel 14a exceeds the pressure on the upstream side of the compressor wheel 14a.

  Here, if the cumulative time is equal to or less than the predetermined time, the amount of air flowing downstream of the compressor wheel 14 a in the intake passage 12 flows into the ejector 54 via the upstream passage 52 in a small amount. Means that there are many. In this case, for example, when the temperature in the vicinity of the ejector 54 falls within a predetermined temperature range (for example, "130 to 150 ° C"), oil mist or particulate matter in the blowby gas may be deposited in the ejector 54. And this causes a so-called blockage which reduces the flow passage cross-sectional area of the ejector 54.

  On the other hand, in the present embodiment, the amount by which the air downstream of the compressor wheel 14 a in the intake passage 12 flows into the ejector 54 through the upstream passage 52 is corrected by increasing and correcting the target boost pressure Pa *. It can be increased. And thereby, the oil etc. which retain in ejector 54 are blown off, and it can suppress that a deposit arises.

  Further, the CPU 62 reduces the target opening degree θs * of the throttle valve 16 calculated by the target throttle opening degree calculation process M20 due to the increase correction of the target boost pressure Pa *. As a result, the increase in the amount of air charged into the combustion chamber 24 can be suppressed due to the increase of the upstream pressure Pu due to the correction amount ΔP, and the load factor KL is controlled to the target load factor KL *. be able to.

<Correspondence relationship>
Correspondence between the matters in the above-mentioned embodiment and the matters described in the above-mentioned "means for solving the problem" is as follows. The adjustment device corresponds to the WGV 34.

<Other Embodiments>
The present embodiment can be modified as follows. The present embodiment and the following modifications can be implemented in combination with one another as long as there is no technical contradiction.

  In the above embodiment, the processing for increasing the upstream pressure Pu, which is the supercharging pressure, is performed when the cumulative time in which the downstream pressure Pd is equal to or higher than the predetermined value during the predetermined period is equal to or less than the predetermined time. It is not limited to this. For example, when the cumulative time of the state in which the upstream pressure Pu is equal to or more than the predetermined value in the predetermined period is equal to or less than the predetermined time, processing may be performed to increase the upstream pressure Pu which is the supercharging pressure.

  In the above embodiment, the WGV 34 is illustrated as an example of the adjustment device that adjusts the amount of exhaust blown to the turbine wheel 14 b among the exhaust gas discharged to the exhaust passage 30, but the present invention is not limited thereto. For example, it may be an actuator that adjusts the pressure receiving area of the variable nozzles that make the area of the turbine wheel 14b pressure receiving the exhaust pressure variable.

In the above embodiment, the target opening degree θs * is calculated based on the target boost pressure Pa *. However, the present invention is not limited thereto. For example, the upstream pressure Pu may be used instead of the target boost pressure Pa *.
The internal combustion engine is not limited to a spark ignition internal combustion engine fueled by gasoline or the like. For example, it may be a compression ignition type internal combustion engine using light oil or the like as a fuel. In this case, the throttle valve may not be provided. However, even in the spark ignition type internal combustion engine, for example, in the case where the valve characteristic variable device for changing the valve characteristic of the intake valve is provided, the throttle valve is not essential, and the charging efficiency is increased by operating the valve characteristic when raising the supercharging pressure. You may suppress the rise of

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 12 ... Intake passage, 14 ... Turbocharger, 14a ... Compressor wheel, 14b ... Turbine wheel, 16 ... Throttle valve, 20 ... Cylinder, 22 ... Piston, 24 ... Combustion chamber, 26 ... Oil pan, 28 ... Crankcase, 30 ... exhaust passage, 32 ... bypass passage, 34 ... WGV, 40 ... atmosphere introduction passage, 42 ... oil separator, 44 ... discharge passage, 46 ... PCV passage, 48 ... PCV valve, 50 ... bypass passage, 52 ... Upstream passage, 54 ... Ejector, 54a ... Suction part, 56 ... Downstream passage, 60 ... Control device, 62 ... CPU, 64 ... ROM, 66 ... Non-volatile memory, 70 ... Upstream pressure sensor, 72 ... Downstream side Pressure sensor,
74 ... crank sensor, 76 ... accelerator sensor.

Claims (1)

Connecting a downstream side and an upstream side of a compressor wheel of the supercharger, and an adjustment device for adjusting an exhaust amount of the exhaust gas discharged to the exhaust passage to be blown to the turbine wheel of the supercharger and the supercharger And an ejector, the suction unit of the ejector being applied to an internal combustion engine connected to a crankcase,
Memory processing for storing a history of states in which the pressure on the downstream side of the turbine wheel is equal to or higher than a predetermined value;
Based on the stored history, when the accumulated time of the state which is equal to or more than the predetermined value in the predetermined period is equal to or less than the predetermined time, the adjusting device is operated to execute the rising process to increase the pressure on the downstream side. Control system for internal combustion engines.