JP2019157836A - Internal combustion engine control device - Google Patents

Abstract

To provide an internal combustion engine control device enabling suppression of the occurrence of deposit and suppression of degradation of performance of the internal combustion engine to be made compatible.SOLUTION: The control device of an internal combustion engine comprising a supercharger is provided, the supercharger including: a turbine provided in an exhaust passage of the internal combustion engine; a compressor supercharging the air flowing in an intake passage of the internal combustion engine; a bypass passage connecting the exhaust passage upstream of the turbine and the exhaust passage downstream of the turbine; and a valve provided in the bypass passage. The control device comprises: an acquisition part acquiring a temperature of the compressor; and a control part which in a case where the compressor temperature of a prescribed value or more continues for a prescribed time or more, reduces an opening of the valve in comparison with a case where the temperature of a prescribed value or more does not continue for the prescribed time or more.SELECTED DRAWING: Figure 2

Description

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

  A technique is known in which a supercharger is rotated by exhaust gas to supercharge combustion air and supply the supercharged air to an internal combustion engine body. As deposits adhere to the compressor of the supercharger, the efficiency of the supercharger decreases, the output of the engine decreases, and the fuel efficiency deteriorates. The deposit is a concentrate of oil mist. The higher the intake air temperature, the easier the deposit is generated. Therefore, when the temperature is high, the generation of deposits is suppressed by reducing the supercharging pressure by the supercharger (for example, Patent Document 1).

JP-A-2018-13093

  However, limiting the supercharging pressure reduces the performance of the internal combustion engine. Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can achieve both suppression of deposit and suppression of deterioration of the performance of the internal combustion engine.

  An object of the present invention is to provide a control device for an internal combustion engine including a supercharger, wherein the supercharger is a turbine provided in an exhaust passage of the internal combustion engine, and a compressor that supercharges air flowing through an intake passage of the internal combustion engine. A bypass passage connecting a portion of the exhaust passage upstream of the turbine and a portion downstream of the turbine, and a valve provided in the bypass passage, and the control device includes: The acquisition unit for acquiring the temperature of the compressor, and when the state where the temperature is equal to or higher than a predetermined value continues for a predetermined time or more, the valve is compared with the case where the temperature is not higher than a predetermined value for a predetermined time or longer. And a controller for reducing the opening degree of the internal combustion engine.

  It is possible to provide a control device for an internal combustion engine that can achieve both suppression of deposit and suppression of deterioration of the performance of the internal combustion engine.

FIG. 1 is a schematic view illustrating an internal combustion engine. FIG. 2 is a flowchart illustrating the control performed by the ECU.

(Embodiment)
Hereinafter, an internal combustion engine 100 of the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram of an internal combustion engine 100. An internal combustion engine 100 shown in FIG. 1 is a gasoline engine, for example, and is mounted on an automobile. The internal combustion engine 100 includes an engine body 10 (internal combustion engine body) and a supercharger 20. An intake passage 12 and an exhaust passage 14 are connected to the engine body 10. The supercharger 20 includes a compressor 22 and a turbine 24.

  The intake passage 12 is provided with a compressor 22, an intercooler 16, an air flow meter 15, and a throttle valve 18 from the upstream side. A bypass passage 26 is provided for connecting a portion upstream of the compressor 22 and a portion downstream of the compressor 22 of the intake passage 12. An air bypass valve (ABV) 28 is provided in the bypass passage 26.

  A turbine 24 and a catalyst 19 are provided in the exhaust passage 14 from the upstream side. A bypass passage 30 is provided that connects a portion of the exhaust passage 14 upstream of the turbine 24 and a portion of the downstream side. The bypass passage 30 is provided with a waste gate valve (WGV) 32. The catalyst 19 is, for example, a three-way catalyst, contains a catalyst metal such as platinum (Pt), palladium (Pd), rhodium (Rh), has an oxygen storage capacity, and purifies NOx, HC and CO.

  In FIG. 1, the flow of air and exhaust is indicated by arrows. Air is supplied to the engine body 10 through the intake passage 12. The intercooler 16 cools the air, and the throttle valve 18 adjusts the air flow rate. The air flow meter 15 detects the intake air amount.

  The engine body 10 burns a mixture of fuel and air, and discharges exhaust gas into the exhaust passage 14. The exhaust gas is purified by the catalyst 19 and discharged outside the vehicle. The turbine 24 provided in the exhaust passage 14 is rotated by exhaust. The compressor 22 is connected to the turbine 24, and the compressor 22 rotates as the turbine 24 rotates. The air flowing through the intake passage 12 is compressed by the compressor 22 and supplied to the engine body 10.

  In order to protect the turbine 24 and supply a stable supercharging pressure, a part of the exhaust gas may flow through the bypass passage 30 downstream of the turbine 24 in the exhaust passage 14. The ECU 40 can adjust the flow rate of the exhaust gas in the exhaust passage 14 and the bypass passage 30 by opening and closing the WGV 32.

  An ECU (Electric Control Unit) 40 (control device) includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a storage device, and the like, and a program stored in the ROM or the storage device Various controls are performed by executing. The ECU 40 acquires the intake air amount from the air flow meter 15 and acquires the temperature of the engine oil from the oil temperature sensor 34. The load of the internal combustion engine 100 correlates with the temperature of the compressor 22. For example, in a high load operation, the intake air amount is large and the temperature of the compressor 22 is high. The ECU 40 can acquire the temperature of the compressor 22 based on the intake air amount. The ECU 40 acquires the opening degrees of the throttle valve 18, ABV 28 and WGV 32, and adjusts these opening degrees. The ECU 40 functions as an acquisition unit that acquires the temperature of the compressor 22 and a control unit that controls the opening degree of the WGV 32.

  By depositing on the compressor 22, the efficiency of the supercharger 20 may be reduced, the output of the internal combustion engine 100 may be reduced, and fuel consumption may be deteriorated. The deposit is an oil concentrate. For example, when the outside air temperature is high, the temperature of the intake air also becomes high. In this case, the oil mist receives a large amount of heat from the intake air, resulting in a large amount of deposit.

  The higher the supercharging pressure by the supercharger 20, the higher the temperature of the intake air after compression. Therefore, for example, by limiting the supercharging pressure to a low level, it is possible to suppress the temperature rise of the intake air and suppress the occurrence of deposits. However, when the boost pressure immediately reaches the upper limit, the performance of the internal combustion engine 100 is degraded. In the present embodiment, deposit generation is suppressed by controlling the opening of the WGV 32.

  FIG. 2 is a flowchart illustrating the control performed by the ECU 40. As shown in FIG. 2, the ECU 40 determines whether or not the oil temperature To is equal to or higher than a predetermined temperature Tth (step S10). If the determination is negative (No), the control ends.

  In the case of an affirmative determination (Yes), the ECU 40 determines whether or not a high load state continues for a predetermined time or more (step S12). If the determination is negative, the control ends. On the other hand, the ECU 40 makes an affirmative determination in step S12 when, for example, the load factor is equal to or greater than a predetermined value in a period of 50% or more in several hundred seconds immediately before step S12. In this case, the state where the temperature of the compressor 22 is high continues. The ECU 40 closes the WGV 32 (step S14) and maintains the WGV 32 in a fully closed state for a certain period of time such as several hundred seconds. Control is complete | finished above.

  According to the present embodiment, the ECU 40 closes the WGV 32 when the high load state continues for a predetermined time or longer. Exhaust gas does not flow through the bypass passage 30 but flows through the exhaust passage 14. Since the flow rate of the exhaust gas increases, the rotational speed of the turbine 24 increases. For this reason, the flow velocity of the intake air in the compressor 22 is increased, and the oil is scattered from the compressor 22. As a result, the generation of deposits due to oil is suppressed. Since the ECU 40 does not have to lower the upper limit of the supercharging pressure, a high supercharging pressure can be obtained. Therefore, it is possible to achieve both suppression of deposit and suppression of performance deterioration of the internal combustion engine 100.

  For example, a temperature sensor that detects the temperature of the compressor 22 may be provided. The ECU 40 closes the WGV 32 when the temperature of the compressor 22 is high for a predetermined time. However, the cost increases by adding a new sensor. Using the correlation between the load and the temperature of the compressor 22, the ECU 40 can estimate that the temperature of the compressor 22 is high in a high load state. Therefore, for example, as shown in FIG. 2, when the high load state is continued, it is considered that the state where the temperature of the compressor 22 is equal to or higher than a predetermined temperature continues for a predetermined time and the opening degree of the WGV 32 is controlled. Since it is not necessary to add a temperature sensor, the cost can be reduced.

  Moreover, when the high load driving | running | working is continuing, it is estimated that the user of the vehicle has requested | required driving | running | working with the high response to operation. Since the WGV 32 is closed and the rotational speed of the turbine 24 is increased, the running requested by the user can be realized.

  In step S14 of FIG. 2, the ECU 40 maintains the WGV 32 in a fully closed state for a predetermined time, and thereafter sets the WGV 32 to a normal state. That is, the WGV 32 may be opened after the WGV 32 is fully closed to increase the rotational speed of the turbine 24 and the oil is scattered. The ECU 40 may completely close the WGV 32 or reduce the opening degree. When the high load (the compressor 22 is high temperature) continues, the ECU 40 may decrease the opening of the WGV 32 as compared with the case where the load is low (the compressor 22 is low temperature). Even if the WGV 32 is not fully closed, the flow rate of the exhaust gas to the bypass passage 30 is reduced by decreasing the opening degree, the flow rate in the exhaust passage 14 is increased, and the rotational speed of the turbine 24 is increased. Thereby, the production | generation of a deposit can be suppressed.

  When the oil temperature To is lower than Tth, the environment is low, for example, when it is cold, and the internal combustion engine 100 is warm. In such a low temperature state, it is difficult to generate deposits. Therefore, the possibility of deposits is small even if the opening of the WGV 32 is not reduced. Further, by opening the WGV 32 and flowing the exhaust gas downstream without passing through the turbine 24, warming of the catalyst 19 is also promoted.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the 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.

DESCRIPTION OF SYMBOLS 10 Engine main body 12 Intake passage 14 Exhaust passage 15 Air flow meter 19 Catalyst 20 Supercharger 22 Compressor 24 Turbine 26, 30 Bypass passage 28 Air bypass valve (ABV)
32 Wastegate valve (WGV)
40 ECU
100 Internal combustion engine

Claims (1)

A control device for an internal combustion engine including a supercharger,
The turbocharger includes a turbine provided in an exhaust passage of the internal combustion engine, a compressor that supercharges air flowing through an intake passage of the internal combustion engine, a portion of the exhaust passage upstream of the turbine, and a turbine. A bypass passage connecting the downstream portion and a valve provided in the bypass passage,
The control device, an acquisition unit for acquiring the temperature of the compressor,
A control unit that reduces the opening of the valve when the temperature is equal to or higher than a predetermined value for a predetermined time or longer than when the temperature is not higher than a predetermined value for a predetermined time or longer. A control apparatus for an internal combustion engine.

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