JP2014020288A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve torque in a low-load and high-rotation region of an internal combustion engine by increasing supercharging effects of the internal combustion engine.SOLUTION: When conditions are established that an operation region of the internal combustion engine is in a low-rotation and high-load region and scavenging control is executed to allow intake air to be blown via a cylinder through an exhaust passage, an amount of cooling medium being distributed in an exhaust manifold is controlled to be smaller than when the conditions are not established, or the distribution of the cooling medium into the exhaust manifold is stopped.

Description

  The present invention relates to a control device for an internal combustion engine. Specifically, the present invention relates to a control device applied to an internal combustion engine having an exhaust manifold cooled by a refrigerant.

  Patent Document 1 discloses a cooling system that includes an exhaust manifold that is connected to an internal combustion engine and is cooled by a refrigerant, and a flow rate adjustment valve that adjusts the amount of refrigerant flowing through the exhaust manifold. In this system, when the closing timing of the exhaust valve is later than the opening timing of the intake valve, the positive pressure wave peak formed by the exhaust in the exhaust manifold is not included in the valve overlap period of the intake valve and the exhaust valve. As such, the amount of refrigerant flowing through the exhaust manifold is adjusted.

JP 2010-159678 A JP-A 63-208607 JP 2010-163903 A

  When the valve overlap period is set so that the valve opening period of the intake valve and the valve opening period of the exhaust valve overlap, when the pressure in the exhaust port is lower than the pressure in the intake port, the exhaust gas is exhausted from the intake port through the cylinder. It becomes a scavenge state where air blows to the port side. Here, when the operating region of the internal combustion engine is in the low rotation and high load region, the pressure difference between the intake port and the exhaust port is large. Therefore, when the scavenging state is realized in the low rotation and high load region, the amount of air blown to the exhaust port side increases. This increases the scavenging effect due to scavenging in the low rotation and high load region.

  However, the more air that blows through, the lower the temperature on the exhaust side. In the case where the exhaust manifold is cooled by the refrigerant, the temperature of the exhaust gas further decreases. When the internal combustion engine has a supercharger, if the temperature of the exhaust gas flowing into the exhaust turbine of the supercharger decreases excessively, a sufficient supercharging effect cannot be obtained and the torque decreases. Can be considered.

  The problem to be achieved by the present invention is also related to this problem. Specifically, the supercharging effect of the internal combustion engine is increased by effectively changing the amount of refrigerant flowing through the exhaust manifold, and the An object of the present invention is to improve torque in a high load rotation range.

  In order to achieve the above object, an internal combustion engine control apparatus according to the present invention includes a supercharger, an exhaust manifold cooled by a refrigerant, and adjusting means for adjusting the amount of refrigerant flowing through the exhaust manifold. Applicable to institutions. In this internal combustion engine control device, when the first condition is satisfied, the amount of the refrigerant flowing through the exhaust manifold is reduced by the adjusting means compared to the case where the first condition is not satisfied. The refrigerant quantity control means for controlling is provided. The “small amount compared to the case where the first condition is not satisfied” includes a case where the refrigerant is circulating in the exhaust manifold, but a case where the amount of the circulating refrigerant is small and a case where the refrigerant does not flow. . The first condition includes that the operating region of the internal combustion engine is in the low rotation and high load region and that scavenging control is performed to blow intake air through the cylinder into the exhaust passage. “The operation region is in the low rotation and high load region” means that the operation region is in a region lower than the arbitrarily set reference rotation number and higher than the arbitrarily set reference load. means. Furthermore, “the scavenge control is executed” includes not only the case where the scavenge control is executed, but also the case where the start of the scavenge control is predicted from the current operation state.

  In the present invention, the refrigerant amount control means may perform control to increase the amount of refrigerant when an elapsed time after the amount of refrigerant is reduced due to the establishment of the first condition reaches a certain time. .

  In the present invention, the refrigerant amount control means may stop the refrigerant flow to the exhaust manifold when the first condition is satisfied.

  In the present invention, the first condition may further include a condition in which the in-cylinder air-fuel ratio of the internal combustion engine is controlled to be the stoichiometric air-fuel ratio.

  Further, in the present invention, the refrigerant amount control means determines the amount of refrigerant when the first condition is not satisfied when the first condition is not satisfied and the internal combustion engine is warming up. However, it may be controlled so that the amount becomes smaller than when the warm-up of the internal combustion engine is completed. The “small amount compared with the case where the warm-up is completed” includes the case where the refrigerant is circulating in the exhaust manifold but the amount of the circulating refrigerant is small and the case where the refrigerant is not circulating.

  In the present invention, when the first condition is satisfied, the refrigerant amount control means decreases the refrigerant amount regardless of whether or not the internal combustion engine has been warmed up. May be.

  In the present invention, the refrigerant amount control means further adjusts the refrigerant amount by the adjusting means when the second condition is satisfied as compared with the case where the second condition and the first condition are not satisfied. It is also possible to perform control so that the number is less than that when the first condition is satisfied. Here, the second condition is that the warm-up of the internal combustion engine is completed, that the operation range of the internal combustion engine is outside the low rotation high load range, and that the in-cylinder air-fuel ratio of the internal combustion engine is equal to the stoichiometric air-fuel ratio. It shall consist of being in the state controlled so that it may become.

  When scavenge control is performed in an operating range of the internal combustion engine in a low rotation and high load range, the amount of air that blows from the intake side to the exhaust side increases, so the temperature of the gas in the exhaust system may excessively decrease. It is done. In this regard, according to the present invention, when the scavenge control is executed in the low rotation and high load region, the amount of the refrigerant flowing through the exhaust manifold is controlled to be smaller than that in a normal case. Thereby, the cooling degree of the exhaust gas by a refrigerant | coolant is reduced. Therefore, even when the operation region is a low rotation and high load region, a high supercharging effect can be obtained while ensuring a large scavenging effect by scavenging control.

  Further, in the present invention, if the amount of refrigerant is increased when the elapsed time after the amount of refrigerant is reduced due to the establishment of the first condition reaches a certain time, the circulation of the refrigerant is reduced. The boiling of the refrigerant can be suppressed.

  Further, in the present invention, if the flow of the refrigerant to the exhaust manifold is stopped, the cooling of the gas in the exhaust manifold can be reliably suppressed, and a higher supercharging effect can be obtained.

  Further, when the air-fuel ratio is controlled to the stoichiometric air-fuel ratio, it is considered that the demand for lowering the exhaust gas temperature and cooling the exhaust system is lower than when the air-fuel ratio is controlled to be rich. In this regard, when the in-cylinder air-fuel ratio is controlled to be the stoichiometric air-fuel ratio in the present invention, if the amount of the refrigerant is reduced, an excessive temperature drop of the exhaust gas is suppressed and a high supercharging effect is achieved. Can be secured.

  In the present invention, if the first condition is not satisfied and the internal combustion engine is warming up, the amount of refrigerant can be reduced as compared with the case where the warming up is completed. The warm-up of the internal combustion engine can be effectively promoted.

  Further, when scavenge control is performed in a low rotation and high load region, the temperature of the exhaust gas becomes low even after the internal combustion engine is warmed up. In this regard, in the present invention, when the first condition is satisfied, if the amount of the refrigerant is reduced regardless of whether or not the warm-up of the internal combustion engine is completed, the low rotation and high load range is obtained. When the scavenge control is executed, the cooling of the exhaust gas is surely weakened, and the temperature reduction of the exhaust gas can be suppressed.

  Even when the operating range of the internal combustion engine is outside the low rotation and high load range, when the air-fuel ratio is controlled to stoichiometric, the exhaust gas temperature decreases compared to when the air-fuel ratio is controlled to be rich. Is considered to be in a low state. In this regard, when the cylinder air-fuel ratio is controlled so as to be the stoichiometric air-fuel ratio even outside the low-rotation and high-load region in the present invention, if the amount of refrigerant is reduced, the exhaust gas excessively decreases in temperature. Can be suppressed, and a high supercharging effect can be secured.

It is a figure for demonstrating the structure of the whole system to which the control apparatus of embodiment of this invention was applied. It is a timing chart which shows the contents of control performed in an embodiment of the invention. It is a flowchart which shows the content of the control performed in embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 1 is a schematic diagram for explaining a configuration of a supercharged engine to which a control device according to an embodiment of the present invention is applied. In FIG. 1, a plurality of lines are drawn. Of these lines, the lines shown by solid lines are lines through which gas (air and exhaust gas) flows, and the lines shown by dotted lines are lines through which cooling water flows. An intake manifold 4 is connected to an intake port of the engine body 2 of the supercharged engine (internal combustion engine), and an intake passage 6 communicates with the intake manifold 4. An exhaust manifold 8 is connected to the exhaust port of the engine body 2, and an exhaust passage 10 communicates with the exhaust manifold 8.

  The engine body 2 according to the present embodiment includes a turbocharger 12 that compresses air (fresh air) using the energy of exhaust gas. The compressor 14 of the turbocharger 12 is disposed in the intake passage 6, and the turbine 16 is disposed in the exhaust passage 10. An intercooler 18 is attached downstream of the compressor 14 in the intake passage 6, and a throttle 20 is disposed further downstream thereof.

  The supercharged engine according to the present embodiment includes two cooling systems 30 and 50. One cooling system 30 is a cooling system mainly for cooling the engine body 2, and relatively high water temperature cooling water flows (hereinafter also referred to as a high water temperature cooling system). The other cooling system 50 is a cooling system mainly for cooling the intercooler 18, and a cooling water having a relatively low water temperature flows (hereinafter also referred to as a low water temperature cooling system).

  The high water temperature cooling system 30 includes a main radiator 32 and also includes a cooling water passage 40 that circulates between the main radiator 32 and the engine body 2. A thermostat 34 and an electric pump 36 are provided on the outlet side of the main radiator 32 in the cooling water passage 40. The electric pump 36 is a pump for sending cooling water to the engine body 2.

  A bypass passage 42 that bypasses the main radiator 32 and is connected to the inlet side of the electric pump 36 is connected to the cooling water passage 40. The bypass passage 42 is connected at one end to a position of the cooling water passage 40 between the inlet of the main radiator 32 and the engine body 2, and is connected between the thermostat 34 and the electric pump 36 at the other end. In the middle of the bypass passage 42, a heater 38 is attached for heating and heating the cooling water when the supercharged engine is started. Further, the high water temperature cooling system 30 includes a cooling water passage 44 that branches from the middle of the cooling water passage 40 and is connected to the inlet side of the electric pump 36 via the thermostat 34.

  The thermostat 34 changes the direction in which the cooling water flows according to the temperature of the cooling water flowing through the cooling water passage 40 from the flow through the main radiator 32 to the flow on the bypass passage 42 side that bypasses the main radiator 32, or the bypass passage. The flow is switched from 42 to the flow through the main radiator 32.

  Further, the high water temperature cooling system 30 further includes an exhaust manifold cooling water passage 46 that branches from the cooling water passage 40 in the vicinity of the inlet of the cooling water passage 40 to the water jacket of the engine body 2 and cools the exhaust manifold 8. ing. The exhaust manifold cooling water passage 46 is provided with a cooling water valve 48 (adjusting means) for opening and closing the exhaust manifold cooling water passage 46. As the cooling water valve 48, a normally open valve is used for fail-safe. The exhaust manifold cooling water passage 46 joins the cooling water passage 40 again in the vicinity of the water jacket outlet.

  The low water temperature cooling system 50 includes a sub radiator 52 smaller than the main radiator 32 and a cooling water passage 56 through which the cooling water cooled by the sub radiator 52 circulates. The cooling water passage 56 is piped around the sub radiator 52, the intercooler 18, and the turbocharger 12. An electric pump 54 for sending cooling water to the intercooler 18 is provided at the outlet of the sub radiator 52. The cooling water sent out by the electric pump 54 passes through the intercooler 18 and then returns to the sub-radiator 52 through the turbocharger 12 again.

  The operation of the supercharged engine according to the present embodiment is controlled by an ECU (Electronic Control Unit) (not shown). The ECU is a control device that performs integrated control of the supercharged engine. The supercharged engine control performed by the ECU includes scavenging control and cooling water valve 48 control. Scavenge control changes the valve overlap period, which is the period when the intake valve and the exhaust valve overlap, by changing the valve timing of the intake valve and the exhaust valve, and the intake air passes through the cylinder. This is a control to make it blow into the exhaust passage. Hereinafter, these control contents will be described.

  FIG. 2 is a timing chart showing the contents of the cooling water valve control executed in the present embodiment. In FIG. 2, the horizontal axis represents time, (A) is the opening degree of the accelerator pedal, (B) is the advance amount of the opening timing of the intake valve, (C) is the flow rate of the cooling water, and (D) is the exhaust gas. The temperature, (E), represents the supercharging pressure and each change.

  In the example of FIG. 2, the operating region of the supercharged engine is in a region where the air-fuel ratio is controlled with the stoichiometric air-fuel ratio as the target air-fuel ratio (hereinafter also referred to as “λ1 region”). As shown in FIG. 2A, at time t1, when the accelerator pedal opening increases and an acceleration request is detected, and it is confirmed that the engine is in a low rotation and high load region, the intake valve is opened. Time is greatly advanced. This increases the valve overlap period and enhances the scavenging effect in the cylinder. In the low-rotation and high-load region, the normal intake port is higher than the exhaust port pressure, so that a scavenging state in which exhaust is blown through the cylinder from the intake port to the exhaust port is realized. After such acceleration transient control, the amount of advance is returned to time t3 according to the driving state.

  As indicated by the broken line in FIG. 2C, conventionally, after the warm-up of the supercharged engine is completed, the cooling water amount is kept at a constant flow rate. On the other hand, as shown by a solid line in FIG. 2C, in the λ1 region, compared to the amount of cooling water to the conventional water-cooled exhaust manifold, or an exhaust manifold cooling channel for cooling the exhaust manifold 8 outside the λ1 region. The amount of cooling water is controlled to be smaller than the amount of cooling water through which 46 is circulated. Specifically, the cooling water valve 48 installed in the exhaust manifold cooling water channel 46 is controlled to be half open. Thereby, the cooling degree of the exhaust manifold 8 is reduced.

  Further, when it is detected that the operation region has shifted to the low rotation / high load region such as an acceleration request and the scavenge control is executed (time t1), the cooling water valve 48 is closed. As a result, the circulation of the cooling water to the exhaust manifold cooling water channel 46 is stopped, and the degree of cooling of the exhaust gas in the exhaust manifold 8 is greatly reduced.

  When the cooling water valve 48 is closed, the cooling water valve 48 is fully opened at a time t2 when a certain time T0 has elapsed after the closing. As a result, a large amount of cooling water flows into the exhaust manifold cooling water channel 46. Thereby, boiling of the cooling water in the exhaust manifold cooling water channel 46 due to the cooling water valve 48 being closed for the predetermined time T0 is suppressed. Thereby, deterioration of the components installed in the exhaust system is suppressed. After the cooling water valve 48 is fully opened for a certain time T0, if the operating state is the λ1 region and the scavenge control is not executed, the cooling water valve 48 is again half opened. Here, the certain period of time is an arbitrarily set time within a time range in which the cooling water does not boil even if the circulation of the cooling water is stopped.

  FIGS. 2D and 2E show the case where the amount of cooling water to the exhaust manifold cooling water passage 46 is not particularly controlled under the same operating conditions, and the cooling water is circulated with the cooling water valve 48 fully opened (broken line). ) And the case where the cooling water amount is changed by controlling the cooling water valve 48 as described above (solid line), the change in the exhaust temperature and the change in the supercharging pressure are respectively compared. As shown in FIG. 2D, by changing the cooling water amount, the exhaust temperature when the operating state of the supercharged engine is in the transition period after the acceleration request is made faster than when the cooling water amount is not changed. Can be raised. Further, as the exhaust gas temperature rises early, as shown in FIG. 2E, it is possible to ensure a high supercharging effect at a low rotation and high load. As a result, the output torque in the low rotation and high load range can be improved and the response to the acceleration request can be improved.

  FIG. 3 is a flowchart for explaining a specific routine of control executed in the embodiment of the present invention. The routine of FIG. 3 is a routine that is repeatedly executed at regular intervals. In the first step S100 of the routine of FIG. 3, the ECU determines whether or not the current operation region is in the λ1 region.

  In step S100, when it is not recognized that it is in the λ1 region, the process proceeds to step S102. In the process of step S102, it is determined whether or not the supercharged engine is currently warming up. Whether or not the engine is warming up is determined based on, for example, the temperature of the cooling water. If it is determined in step S102 that the supercharged engine is warming up, the cooling water valve 48 is set to a half-open state (S104). Thus, even when the engine is not in the λ1 region, excessive cooling of the exhaust system during engine warm-up is suppressed, and warm-up is promoted. On the other hand, when it is not recognized in step S104 that the engine is warming up, the cooling water valve 48 is set to fully open (S108). As a result, the exhaust manifold 8 is reliably cooled not in the λ1 region but after warming up. Thereafter, the current process is temporarily terminated.

  On the other hand, if it is determined in step S100 that the current engine operating region is the λ1 region, the process proceeds to step S108, and whether or not the current operating region is the low rotation high load region. Is determined. Specifically, the operating range depends on whether the engine speed of the current engine is equal to or less than the arbitrarily set reference speed and whether the current load is higher than the arbitrarily set reference load. Is in the low rotation high load region.

  In step S108, when it is not recognized that the operation region is the low rotation high load region, the process proceeds to step S110, where it is determined whether or not the engine is warming up. If it is determined in step S110 that the engine is warming up, the cooling water valve 48 is closed (S112). Thereby, cooling of the exhaust manifold during engine warm-up is suppressed, and warm-up can be promoted. On the other hand, when it is not recognized in step S112 that the engine is warming up, the cooling water valve 48 is opened halfway (S114). When the operation region is in the λ1 region, it is considered that it is less necessary to lower the temperature of the exhaust gas than in the rich region. Accordingly, even in a region other than the low rotation and high load, by reducing the amount of cooling water to the exhaust manifold cooling water channel 46, excessive cooling of the exhaust system can be suppressed and the supercharging pressure can be secured. Thereafter, the current process ends.

  On the other hand, if it is determined in step S108 that the operation region of the engine body 2 is in the low rotation and high load region, it is determined whether or not scavenge control is executed (S116). Here, the scavenge control is executed by a separately set routine. In the process of step S116, it is determined that the scavenge control is executed when it is already in the scavenge state by the scavenge control execution routine or when it is predicted that the scavenge control is started and enters the scavenge state. In other cases, it is determined that the scavenge control is not executed.

  If it is determined in step S116 that scavenge control is not executed, the process proceeds to step S110. In this case, similarly to the above, it is determined in step S110 whether or not the engine is warming up. If it is determined in step S110 that the engine is warming up, the cooling water valve 48 is closed (S112). If it is not determined that the engine is warming up, the cooling water valve 48 is half open. (S114). Thereafter, the current process is temporarily terminated.

  On the other hand, if it is determined in step S116 that scavenge control is to be executed, the cooling water valve 48 is then closed (S118). Thereby, the circulation of the cooling water to the exhaust manifold 8 during the scavenge control is stopped. Therefore, excessive cooling of the exhaust system during scavenging control in a low rotation high load region is suppressed, and a supercharging pressure is secured.

  Next, it is determined whether or not the elapsed time starting from the closing of the cooling water valve 48 has reached a certain time T0 (S120). If it is not recognized that the predetermined time T0 has been reached, the process returns to step S120. That is, until the elapse of the predetermined time T0 is recognized in step S120, the elapse time determination processing in step S120 is repeatedly executed at every predetermined processing time.

  On the other hand, if the elapse of the predetermined time T0 is recognized in step S120, the process proceeds to step S122, and the cooling water valve 48 is fully opened. As a result, the cooling water that has been stopped by closing the cooling water valve 48 for a predetermined time T0 is in a state of flowing to the exhaust manifold 8. Thereby, boiling of the cooling water due to the suspension of the circulation of the cooling water valve 48 is suppressed. Thereafter, the current process is temporarily terminated.

  As described above, in the present embodiment, when the scavenge control is executed in the low rotation high load region, the cooling water valve 48 is closed and the circulation of the cooling water to the exhaust manifold 8 is stopped. Thereby, cooling of the exhaust gas in a low rotation and high load region can be suppressed, and a high supercharging effect can be ensured.

  In the present embodiment, when the elapsed time after the cooling water valve 48 is closed during the scavenge control in the low rotation high load region becomes the constant time T0, the cooling water valve 48 is set to the constant time T0. In the meantime, the case of fully opening was demonstrated. However, in the present invention, the time for closing the cooling water valve 48 and the time for full opening need not be the same, and each time can be set arbitrarily. Further, the present invention does not perform control to fully open the cooling water valve 48 after the cooling water valve 48 is closed for a certain time, and after the cooling water valve 48 is closed for a certain time, the cooling water valve 48 is in a half-open state. Thus, the half open state may be maintained as it is until a predetermined condition is satisfied in the λ1 region. Further, the present invention is not limited to the control of fully closing and fully opening the cooling water valve 48. For example, in the scavenge control, the opening of the cooling water valve 48 is reduced to reduce the flow rate of the cooling water, and then the cooling water amount is reduced. The opening degree of the cooling water valve 48 may be increased so as to increase more.

  Further, in the present embodiment, the case where the cooling water valve 48 is closed and the circulation of the cooling water to the exhaust manifold cooling water channel 46 is stopped when the scavenge control is executed in the low rotation high load region has been described. However, the present invention is not limited to this, as long as the opening degree of the cooling water valve 48 is reduced and the flow rate of the cooling water to the exhaust manifold cooling water passage 46 is reduced.

  Moreover, in this Embodiment, the case where the cooling water valve 48 was made into the three states of full open, half open, and valve closing was demonstrated. However, the present invention is not limited to this. For example, a plurality of openings are set according to each of steps S104, S106, S112, S114, S118, and S122 in FIG. May be. In addition, the present invention is not limited to the setting of the opening degree of the cooling water valve 48 in this way. For example, it is detected that the low-rotation and high-load region is present, and it is confirmed that the scavenging control is being performed. In such a case, control may be performed to reduce the opening by a predetermined amount from the opening of the cooling water valve 48 set at that time.

  Further, in the present embodiment, the case where the cooling water valve 48 is closed on the condition that the scavenge control is executed in the λ1 region and the low rotation high load region has been described. However, the present invention is not limited to the λ1 region, but also when scavenging control is performed in other air-fuel ratio regions at low rotation and high load, similarly, the cooling water valve 48 is closed or its opening degree is reduced. Thus, the amount of cooling water flowing through the exhaust manifold cooling water channel 46 may be reduced.

  In the present embodiment, when the engine is in the λ1 region and not in the low rotation / high load region, the cooling water valve 48 is closed during the warm-up of the engine in the λ1 region (S112). Has been described as being half open (S104). However, the present invention is not limited to this, and in either case, it may be half open or fully closed. In addition, the present invention is not limited to the case where the cooling water valve 48 is half-opened and fully closed. For example, in each case of the λ1 region and not the low rotation high load region and the λ1 region, the engine If the opening degree of each cooling water valve 48 is controlled so that the amount of cooling water flowing through the exhaust manifold cooling water passage 46 is smaller when the engine is warming up than when the engine is warmed up. Good.

  Further, in the present embodiment, in the case of the λ1 region, the cooling water valve 48 is half-opened even in a region other than the low rotation and high load region, so that the amount of cooling water flowing through the exhaust manifold cooling water channel 46 can be reduced. The case of reducing the above has been described. However, the present invention is not limited to this, and the cooling water valve 48 may be fully opened in a region other than the low rotation and high load region. Further, even when the amount of cooling water is reduced, the cooling water valve 48 is not limited to a half-open state, but the amount of cooling water flowing through the exhaust manifold cooling water passage 46 with an appropriate opening degree is set to the cooling water valve 48. May be less than when fully open.

  Further, in FIG. 2 of the present embodiment, the timing chart in which the scavenge control and the cooling water valve 48 are simultaneously performed when the acceleration request is confirmed has been described. However, the present invention is not limited to this. For example, when the acceleration request is confirmed and the driving state is predicted to execute the scavenge control, it is not necessary to wait for the start of the scavenge control. The cooling water valve 48 may be closed first (or control for reducing the opening degree).

  In the example of FIG. 2, the case where there is an acceleration request as an example of the low rotation and high load region has been described, but the present invention is not limited to this. For example, the required high supercharging pressure can be sufficiently ensured by performing the same control when a low rotation and high load is caused by other conditions such as when climbing a hill.

  In other cases, in the above embodiment, when the number of each element, quantity, quantity, range, etc. is mentioned, unless otherwise specified or clearly specified in principle, that number The invention is not limited to the number mentioned. The structures, steps, and the like described in this embodiment are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

2 Engine body 4 Intake manifold 6 Intake passage 8 Exhaust manifold 10 Exhaust passage 12 Turbo supercharger 14 Compressor 16 Turbine 18 Intercooler 20 Throttle 30 High water temperature cooling system 32 Main radiator 34 Thermostat 36 Electric pump 38 Heater 40 Cooling water passage 42 Bypass Passage 44 Cooling water passage 46 Exhaust manifold cooling passage 48 Cooling water valve 50 Low water temperature cooling system 52 Sub-radiator 54 Electric pump 56 Cooling water passage

Claims (7)

A turbocharger,
An exhaust manifold cooled by a refrigerant;
Adjusting means for adjusting the amount of refrigerant flowing through the exhaust manifold, and is applied to an internal combustion engine,
The operating region of the internal combustion engine is in a low rotation high load region;
Scavenging control is performed to allow the intake air to blow through the exhaust passage into the exhaust passage;
When the first condition is established, the amount of the refrigerant flowing through the exhaust manifold is reduced by the adjusting means as compared with the case where the first condition is not satisfied. A control apparatus for an internal combustion engine, comprising a refrigerant amount control means for controlling.   The refrigerant amount control means performs control to increase the amount of the refrigerant when an elapsed time after the amount of the refrigerant is decreased due to the establishment of the first condition reaches a certain time. Item 2. A control device for an internal combustion engine according to Item 1.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the refrigerant amount control means stops the flow of the refrigerant to the exhaust manifold when the first condition is satisfied. .   4. The method according to claim 1, wherein the first condition further includes, as a condition, a state in which a cylinder air-fuel ratio of the internal combustion engine is controlled to be a stoichiometric air-fuel ratio. The control device for an internal combustion engine according to claim 1.   When the first condition is not satisfied and the internal combustion engine is warming up, the refrigerant amount control means determines the amount of the refrigerant when the first condition is not satisfied. 5. The control device for an internal combustion engine according to claim 1, wherein the control is performed so that the amount is smaller than that when the warm-up of the internal combustion engine is completed.   When the first condition is satisfied, the refrigerant amount control means performs control to reduce the amount of the refrigerant regardless of whether or not the internal combustion engine has been warmed up. 6. The control device for an internal combustion engine according to claim 1, wherein the control device is an internal combustion engine. The refrigerant amount control means further includes:
That the internal combustion engine has been warmed up;
The operating region of the internal combustion engine is outside the low rotation high load region;
The in-cylinder air-fuel ratio of the internal combustion engine is controlled to be the stoichiometric air-fuel ratio;
When the second condition is established, the amount of the refrigerant is reduced by the adjusting means as compared with the case where the second condition and the first condition are not satisfied, and the first condition is satisfied. The control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein the control is performed so that the condition is satisfied when the condition is satisfied.

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