JP6648536B2 - Warm-up promotion system for internal combustion engine - Google Patents

Description

  The present invention relates to a warm-up promotion system for promoting warm-up of an internal combustion engine.

2. Description of the Related Art Conventionally, a warm-up promotion technology that promotes warm-up immediately after the start of an internal combustion engine to reduce friction and improve fuel efficiency has been studied.
For example, Patent Document 1 below has a plurality of cooling medium passages through which a cooling medium is introduced into an internal combustion engine, and among the cooling medium passages, a cooling medium flowing through a first cooling medium passage connected to a cylinder block is provided. , The EGR cooler exchanges heat with the exhaust gas. Since the temperature of the cooling medium is increased by the exhaust gas, the warming-up of the cylinder block is promoted, and a temperature difference is provided between the cooling medium and other parts of the internal combustion engine to bring each part into an appropriate temperature state.

JP 2011-47305 A

  By using the exhaust heat of the EGR cooler for warming up the internal combustion engine as in the prior art described above, it is possible to promote warming up without complicating the vehicle configuration. On the other hand, in the above-described related art, there is room for improvement in performing warming-up more efficiently.

  The present invention has been made in view of such circumstances, and an object of the present invention is to promote warming-up of an internal combustion engine more efficiently.

In order to achieve the above object, a warm-up promotion system for an internal combustion engine according to the present invention includes a first flow path adjusting mechanism for changing a flow path area of an exhaust passage for discharging exhaust gas discharged from the internal combustion engine to the outside of the vehicle. And changing a flow passage area of an exhaust recirculation passage branched from the exhaust passage on the exhaust gas flow upstream side of the first flow passage adjusting mechanism and returning the exhaust gas to an intake passage of the internal combustion engine. A flow path adjusting mechanism, and branching from the exhaust gas recirculation passage on the upstream side of the exhaust gas flow from the second flow path adjusting mechanism to the exhaust passage on the downstream side of the exhaust gas flow from the first flow path adjusting mechanism. A third flow path adjusting mechanism for changing a flow path area of a bypass passage connected to the exhaust passage, and a third flow path adjusting mechanism provided on the exhaust gas recirculation passage upstream of the exhaust gas flow from a branch with the bypass passage, wherein the cooling medium discharges the exhaust gas. Exhaust to cool gas And over La, the joint between the exhaust cooler and the internal combustion engine, a cooling passage that allows heat exchange between the cooling medium and the internal combustion engine, the exhaust gas stream upstream of the first flow path adjustment mechanism A pressure in the exhaust gas recirculation passage on the upstream side of the exhaust gas flow of the second flow path adjusting mechanism, and a pressure in the exhaust gas recirculation path on the upstream side of the exhaust gas flow of the second flow path adjusting mechanism. And a pressure sensor for detecting any one of the pressures in the bypass passage on the side of the cooling medium, and when the temperature of the cooling medium is lower than a predetermined temperature, the first flow path adjusting mechanism and the second The third flow path adjustment mechanism and the third flow path adjustment mechanism restrict the flow path area of each flow path, and when the pressure is equal to or higher than a predetermined pressure, the third flow path adjustment mechanism The passage area of the passage is enlarged, and the passage area of the bypass passage is reduced. If the pressure after it becomes large at the predetermined pressure or more, the first flow path adjustment mechanism to enlarge the flow passage area of the exhaust passage, characterized in that.
In the warm-up promotion system for an internal combustion engine according to the present invention, the third flow path adjusting mechanism may be configured such that the flow path area of the bypass path is larger than the flow path area of the exhaust path limited by the first flow path adjusting mechanism. The area is increased.
The warm-up promotion system for an internal combustion engine according to the present invention is configured such that, when the temperature of the cooling medium is equal to or higher than the predetermined temperature, the first flow path adjusting mechanism is configured to perform the operation when the temperature of the cooling medium is lower than the predetermined temperature. The flow passage area of the exhaust passage is larger than that of the exhaust passage.

According to the present invention, an area surrounded by the first flow path adjustment mechanism, the second flow path adjustment mechanism, and the third flow path adjustment mechanism (hereinafter, simply referred to as an “area”), that is, an area including an exhaust cooler. Since the pressure inside the region is increased, the temperature of the exhaust gas in this region increases, and the flow rate of the exhaust gas in the region decreases. As a result, the amount of heat transferred from the exhaust gas to the cooling medium in the exhaust cooler increases, and the temperature of the cooling medium is increased more quickly than simply introducing the exhaust gas into the exhaust recirculation passage, thereby warming up the internal combustion engine. The above is advantageous.
According to the present invention, the flow passage area of the bypass passage is made larger than the flow passage area of the exhaust passage. Therefore, the amount of exhaust gas introduced from the exhaust gas recirculation passage into the bypass passage is smaller than the amount of exhaust gas introduced from the exhaust gas passage into the exhaust gas recirculation passage. Is advantageous.
According to the present invention, when the pressure in the region becomes excessively high, the pressure is adjusted by the flow path adjusting mechanism. Therefore, damage to the piping due to excessive pressure is prevented, and the durability of the warm-up promotion system is improved. The above is advantageous. Further, since the opening degree of the first flow path adjustment mechanism is increased after the third flow path adjustment mechanism is fully opened, the pressure in the region is adjusted without reducing the amount of exhaust gas introduced into the exhaust gas recirculation passage as much as possible. This is advantageous in warming up the internal combustion engine in a short time.
According to the present invention, when the temperature of the cooling medium becomes equal to or higher than the predetermined temperature, the amount of exhaust gas introduced into the exhaust gas recirculation passage is reduced, and the amount of heat exchange with the cooling medium in the exhaust cooler is reduced. Therefore, transfer of heat from the cooling medium to the internal combustion engine is prevented, which is advantageous in maintaining the internal combustion engine at an appropriate temperature.

It is an explanatory view showing the composition of the warming-up promotion system 10 concerning an embodiment. FIG. 3 is an explanatory diagram illustrating a functional configuration of an ECU 50. FIG. 2 is an explanatory diagram showing a state of a warm-up promotion system 10 during a warm-up operation of an internal combustion engine 20. FIG. 4 is an explanatory diagram illustrating a state when a load is applied to the internal combustion engine during a warm-up operation.

Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
In the following description, “upstream” and “downstream” respectively mean “upstream of exhaust gas flow” and “downstream of exhaust gas flow”.
FIG. 1 is an explanatory diagram illustrating a configuration of a warm-up promotion system 10 according to the embodiment.
The exhaust gas discharged from the internal combustion engine (engine) 20 is discharged to the outside of the vehicle through the exhaust passage LA. On the exhaust passage LA, a catalyst 22 for purifying harmful components in the exhaust gas by reduction and oxidation, a first passage adjusting mechanism 40 for adjusting the passage area of the exhaust passage LA, and the exhaust gas is discharged to the outside. A muffler 24 is provided to reduce the sound generated at the time.

In the exhaust passage LA, an exhaust recirculation passage LB that recirculates the exhaust gas to the intake passage LD of the internal combustion engine 20 branches from a point P1 on the exhaust gas flow upstream side of the first flow path adjusting mechanism 40. In the present embodiment, the exhaust gas recirculation passage LB is located upstream of the first flow path adjusting mechanism 40 and downstream of the catalyst 22. Exhaust gas that passes through the exhaust gas recirculation passage LB and is used for combustion again in the internal combustion engine 20 becomes exhaust gas recirculation (EGR) gas.
The amount of exhaust gas recirculated to the intake passage LD of the internal combustion engine 20 is adjusted using a second flow passage adjusting mechanism (EGR valve) 42 that changes the flow passage area of the exhaust recirculation passage LB. The second flow path adjusting mechanism 42 is provided in the exhaust gas recirculation path LB downstream of a branch position P2 with a bypass path LC described later.

An exhaust cooler 26 that cools high-temperature exhaust gas is provided on the exhaust gas recirculation passage LB. A cooling medium such as a cooling liquid circulates in the exhaust cooler 26, and the cooling medium exchanges heat with the exhaust gas to cool the exhaust gas.
An exhaust cooler cooling passage 28 through which a cooling medium circulates is connected to the exhaust cooler 26. The exhaust cooler cooling passage 28 connects the exhaust cooler 26 and the internal combustion engine 20 and enables heat exchange between the cooling medium passing through the exhaust cooler 26 and the internal combustion engine 20.
A pump 30 may be provided to circulate the cooling medium in the exhaust cooler cooling passage 28 and actively exchange heat with the exhaust. The pump 30 operates at least during warm-up of the internal combustion engine 20.

From the exhaust recirculation passage LB, a bypass passage LC branches from the downstream of the exhaust cooler 26 to discharge the exhaust gas cooled by the exhaust cooler 26 to the exhaust passage LA without returning to the intake passage LD. That is, the bypass passage LC branches off from the exhaust recirculation passage LB on the downstream side of the exhaust gas flow of the exhaust cooler 26 and on the upstream side of the exhaust gas flow of the second flow path adjustment mechanism 44. It is connected to the exhaust passage LA on the downstream side of the exhaust gas flow. In the present embodiment, the other end of the bypass passage LC is connected to a position P3 upstream of the muffler 24 on the exhaust passage LA.
Further, a third flow path adjusting mechanism 44 that changes the flow area of the bypass path LC is provided downstream of the branch position P2 with the exhaust recirculation path LB in the bypass path LC.

Further, the exhaust gas recirculation passage LB is provided with a pressure sensor 18 for detecting a pressure in the passage.
In the present embodiment, it is assumed that the pressure sensor 18 is provided downstream of the exhaust cooler 26 in the exhaust gas recirculation passage LB, but the pressure sensor 18 is installed in the internal combustion engine 20, the first flow path adjustment. Any location can be used as long as the pressure in the region R (the shaded portion in FIG. 3) surrounded by the mechanism 40, the second flow path adjustment mechanism 42, and the third flow path adjustment mechanism 44 can be detected. For example, when the pressure sensor 18 is disposed in the exhaust recirculation passage LB downstream of the exhaust cooler 26 and upstream of the branch position P2, heat damage from the exhaust gas is detected in order to detect the pressure of the exhaust cooled by the exhaust cooler 26. Hard to receive.

  The internal combustion engine 20 is provided with a knock sensor 19 that detects knocking that occurs during a high-load operation or the like. Knock sensor 19 detects knocking vibration of internal combustion engine 20 using a piezoelectric element or the like. The knock sensor 19 is connected to an ECU 50 described later. When knocking is detected by the knock sensor 19, the ECU 50 performs ignition retard or the like in the internal combustion engine 20.

The internal combustion engine 20 is provided with a water jacket around the combustion chamber. By performing heat exchange between a cooling medium circulating in the water jacket and the combustion chamber, overheating of the internal combustion engine 20 due to combustion is reduced. Preventing.
The above-described exhaust cooler cooling passage 28 communicates with a water jacket in the internal combustion engine 20, and introduces the cooling medium that has passed through the exhaust cooler 26 into the water jacket.
The exhaust cooler cooling passage 28 is provided with a temperature sensor 16 for detecting the temperature of the cooling medium.

An engine cooling path 34 is also connected to the water jacket. The engine cooling passage 34 connects the internal combustion engine 20 and the radiator 32, and the cooling medium whose temperature has risen by removing heat from the internal combustion engine 20 is cooled by the radiator 32 and returned to the internal combustion engine 20.
The engine cooling passage 34 is provided with a pump 36 and a thermostat valve 38.
The pump 36 circulates a cooling medium in the engine cooling path 34.
The thermostat valve 38 is provided upstream of the radiator 32, and closes when the cooling medium is lower than a predetermined temperature (for example, 70 ° C.), that is, during warm air, and prevents the cooling medium from entering the radiator 32. In this case, the cooling medium circulates without cooling through the radiator bypass passage 34A.
When the temperature of the cooling medium is equal to or higher than the predetermined temperature, that is, after the completion of warm-up, the thermostat valve 38 is opened to allow the cooling medium to enter the radiator 32. In this case, the cooling medium is cooled by the radiator 32 and the temperature decreases.
As described above, both the engine cooling passage 34 and the exhaust cooler cooling passage 28 communicate with the water jacket of the internal combustion engine 20, and the cooling medium that has passed through each cooling passage is mixed in the water jacket.

The first flow path adjustment mechanism 40 and the third flow path adjustment mechanism 44 are, for example, butterfly valves, and each of the first and second flow path adjustment mechanisms 44 and 90 is rotated by a valve body D around a valve rod S in a range of 0 to 90 degrees. The passage area of the passage to be adjusted is adjusted.
FIG. 1 is a diagram illustrating a state in which the first flow path adjusting mechanism 40 and the third flow path adjusting mechanism 44 minimize the flow path area of each of the adjustment target paths (flow path area = 0), that is, fully close. Is shown. At this time, the rotation angle of the valve body D is 0 degree. When the rotation angle of the valve body D becomes 90 degrees, the flow passage area of the passage becomes the maximum (flow passage area / piping cross-sectional area), that is, fully open.

The second flow path adjusting mechanism 42 is, for example, a globe valve having a general EGR valve structure.
The degree of opening of the second flow path adjustment mechanism 42 is controlled based on the amount of exhaust gas recirculated to the intake passage LD (EGR gas amount).
More specifically, the ECU 50, which will be described later, determines the load of the internal combustion engine 20, the number of revolutions, the pressure in the region R, and the opening degree of the second flow path adjustment mechanism 42 (the flow area of the exhaust recirculation passage LB, the EGR gas amount). And an EGR introduction map indicating the relationship between the second passage adjustment mechanism 42 and the opening degree of the second flow path adjustment mechanism 42 is changed based on the EGR introduction map.
When the second flow path adjustment mechanism 42 is fully closed, the flow path area of the exhaust gas recirculation passage LB becomes minimum (flow path area = zero), and the second flow path adjustment mechanism 42 is fully opened. In such a case, the flow passage area of the exhaust gas recirculation passage LB becomes the maximum (flow passage area / pipe cross-sectional area).

The opening / closing state of the first flow path adjustment mechanism 40, the second flow path adjustment mechanism 42, and the third flow path adjustment mechanism 44 is controlled by the ECU 50 that controls the operation state of the internal combustion engine 20.
FIG. 2 is an explanatory diagram showing a functional configuration of the ECU 50.
An ECU (Engine Control Unit) 50 includes a CPU, a ROM for storing and storing a control program and the like, a RAM as an operation area of the control program, an EEPROM for rewritably holding various data, and an interface unit for interfacing with peripheral circuits and the like. It is comprised including.
The ECU 50 is connected to an accelerator pedal sensor 52 for detecting the amount of accelerator operation by the driver, a wheel speed sensor 54 for detecting the rotational speed of each wheel of the vehicle, and various sensors such as the above-described temperature sensor 16, pressure sensor 18, and knock sensor 19. Have been.

In the present embodiment, the ECU 50 controls the opening / closing state of each flow path adjusting mechanism as follows based on the temperature of the cooling medium and the operating state of the internal combustion engine 20.
FIG. 3 is an explanatory diagram illustrating a state of the warm-up promotion system 10 during the warm-up operation of the internal combustion engine 20.
Immediately after the start of the vehicle or the like, the temperature of the internal combustion engine 20 is low, so that the warm-up operation for promoting the warm-up of the internal combustion engine 20 is performed. Whether or not to perform the warm-up operation is determined by the ECU 50 using the detection value of the temperature sensor 16. That is, when the detection value of the temperature sensor 16 is lower than the predetermined temperature, the ECU 50 sets the warm-up promotion system 10 in the following state.
In FIG. 3, it is assumed that no load is applied to the internal combustion engine 20 (for example, an idling state).
During the warm-up operation, the cooling medium is not cooled by the radiator 32 because the thermostat valve 38 is closed.

During the warm-up operation, the ECU 50 controls the exhaust passage LA, the exhaust recirculation passage LB, and the bypass passage LC by the first passage adjustment mechanism 40, the second passage adjustment mechanism 42, and the third passage adjustment mechanism 44. Restrict the flow channel area.
More specifically, for example, the rotation angle of the valve body D of the first flow path adjustment mechanism 40 is set to 0 degree to be in the fully closed state, and the third flow path adjustment mechanism 44 is set to, for example, the rotation angle of the valve body D of 45 degrees. Degrees and half open. That is, the third flow path adjusting mechanism 44 makes the flow path area of the bypass passage LC larger than the flow area of the exhaust passage LA restricted by the first flow path adjusting mechanism 40.
Further, as described above, no load is applied to the internal combustion engine 20, and the second flow path adjustment mechanism 42 is in a fully closed state.

In this case, the entire amount of the exhaust gas discharged from the internal combustion engine 20 is introduced into the exhaust gas recirculation passage LB, and passes through the exhaust cooler 26. Further, the amount of exhaust gas discharged to the outside of the vehicle through the bypass passage LC is restricted, and the internal combustion engine 20, the first flow path adjustment mechanism 40, the second flow path adjustment mechanism 42, and the third flow path adjustment mechanism The pressure in a region R (shaded portion) surrounded by 44 increases, and the exhaust gas temperature in this region R increases. Further, the flow velocity of the exhaust gas in the region R becomes slow, and the time during which the exhaust gas stays in the region R becomes longer.
As a result, the amount of heat transferred from the exhaust gas to the cooling medium in the exhaust cooler 26 increases, and the temperature of the cooling medium is increased more quickly than simply introducing the exhaust gas into the exhaust recirculation passage LB, thereby warming the internal combustion engine 20. Opportunity.
In general, it is known that the performance of the catalyst 22 decreases at low temperatures. However, in the present embodiment, since the catalyst 22 is disposed in the region R, it is possible to increase the temperature of the catalyst 22 in a short time. As a result, the performance of the catalyst 22 can be efficiently exhibited.

FIG. 4 is an explanatory diagram illustrating a state when a load is applied to the internal combustion engine 20 during the warm-up operation.
When the accelerator pedal is depressed during the warm-up operation and a load is applied to the internal combustion engine 20, the amount of exhaust gas from the internal combustion engine 20 increases. For this reason, the pressure in the region R increases more than in the state where no load is applied as shown in FIG.
In addition, the second flow path adjusting mechanism 42 is opened according to the above-described EGR introduction map, and a part of the exhaust gas is returned to the intake path LD via the exhaust recirculation path LB.

When the pressure in the region R detected by the pressure sensor 18 becomes equal to or higher than the predetermined pressure, the ECU 50 first increases the opening degree of the third flow path adjustment mechanism 44 to increase the opening degree of the bypass passage LC as shown in FIG. 4A. Increase the flow area. As a result, the amount of exhaust gas discharged outside the vehicle via the bypass passage LC increases, and the pressure in the region R decreases. At this time, the opening degree of the third flow path adjusting mechanism 44 is increased until the pressure in the region R becomes lower than the predetermined pressure.
Further, when the amount of exhaust gas from the internal combustion engine 20 is large, for example, when the third passage adjustment mechanism 44 is fully opened to maximize the passage area of the bypass passage LC, the pressure in the region R is equal to or higher than a predetermined pressure. The ECU 50 increases the opening degree of the first flow path adjusting mechanism 40 to increase the flow path area of the exhaust passage LA as shown in FIG. 4B. As a result, the amount of exhaust gas introduced into the exhaust gas recirculation passage LB decreases, and the pressure in the region R decreases.
By doing so, the heat transfer from the exhaust gas to the cooling medium is promoted while preventing the piping from being damaged due to the pressure increase in the region R, and the internal combustion engine 20 is warmed up early. Can be.
As shown in FIG. 4A, first, the opening of only the third flow path adjusting mechanism 44 is adjusted when the opening of the first flow path adjusting mechanism 40 is increased. This is because the amount of exhaust gas to be reduced decreases, the amount of heat exchange in the exhaust cooler 26 decreases, and the time required for completing warm-up increases.

When the temperature of the cooling medium becomes equal to or higher than the predetermined temperature and the warm-up is completed, the ECU 50 increases the opening degree of the first flow path adjusting mechanism 40, and during the warm-up (when the temperature of the cooling medium is lower than the predetermined temperature). ), The flow passage area of the exhaust passage LA is enlarged.
As a result, the amount of exhaust gas introduced into the exhaust recirculation passage LB decreases, the amount of heat transferred from the exhaust gas to the cooling medium in the exhaust cooler 26 decreases, and overheating of the internal combustion engine 20 can be prevented.

As described above, according to the warm-up promotion system 10 according to the embodiment, the pressure in the region R including the exhaust cooler 26 is increased during the warm-up of the internal combustion engine 20, so that the exhaust gas in the region R is increased. As the temperature increases, the flow rate of the exhaust gas in the region R decreases. As a result, the amount of heat transferred from the exhaust gas to the cooling medium in the exhaust cooler 26 increases, and the temperature of the cooling medium is increased more quickly than simply introducing the exhaust gas into the exhaust recirculation passage LB, thereby warming the internal combustion engine 20. This is advantageous for planning.
Further, according to the warm-up promoting system 10, the flow passage area of the bypass passage LC is made larger than the flow passage area of the exhaust passage LA. Therefore, the amount of exhaust gas introduced from the exhaust gas recirculation passage LB to the bypass passage LC becomes smaller than the amount of exhaust gas introduced from the exhaust passage LA to the exhaust gas recirculation passage LB, and the pressure in the region R is reduced. This is advantageous in assuredly ascending.
Further, according to the warm-up promotion system 10, when the pressure in the region R becomes too high, the pressure is adjusted by the respective flow path adjusting mechanisms. Therefore, breakage of piping due to excessive pressure is prevented, and warm-up is promoted. This is advantageous in improving the durability of the system 10. At this time, since the opening degree of the first flow path adjusting mechanism 40 is increased after the third flow path adjusting mechanism 44 is fully opened, the area of the exhaust gas introduced into the exhaust gas recirculation passage LB is not reduced as much as possible. This is advantageous in adjusting the pressure in the R and warming up the internal combustion engine 20 in a short time.
Further, according to the warm-up promoting system 10, when the temperature of the cooling medium becomes equal to or higher than the predetermined temperature, the amount of exhaust gas introduced into the exhaust recirculation passage LB is reduced, and heat exchange with the cooling medium in the exhaust cooler 26 is performed. Reduce the volume. For this reason, it is advantageous to prevent the internal combustion engine 20 from being overheated by the cooling medium and maintain the internal combustion engine 20 at an appropriate temperature.

  10 warm-up promotion system, 20 internal combustion engine, 26 exhaust cooler, 28 exhaust cooler cooling path, 32 radiator, 34 engine cooling path, 40 first flow path adjusting mechanism , 42 second flow path adjusting mechanism, 44 third flow adjusting mechanism, 50 ECU, 52 accelerator pedal sensor 54 wheel speed sensor LA exhaust path LB ... Exhaust recirculation passage, LC ... Bypass passage.

Claims (3)

A first flow path adjusting mechanism that changes a flow path area of an exhaust passage that discharges exhaust gas discharged from the internal combustion engine to the outside of the vehicle;
A second flow path that changes a flow area of an exhaust recirculation passage that branches from the exhaust passage upstream of the first flow passage adjusting mechanism and that recirculates the exhaust gas to an intake passage of the internal combustion engine; An adjustment mechanism;
A bypass passage branched from the exhaust gas recirculation passage upstream of the second flow passage adjustment mechanism and upstream of the exhaust gas flow and connected to the exhaust passage downstream of the first flow passage adjustment mechanism and downstream of the exhaust gas flow; A third flow path adjusting mechanism for changing a flow path area;
An exhaust cooler that is provided on the exhaust gas recirculation passage on the exhaust gas flow upstream side of the branch with the bypass passage, and cools the exhaust gas with a cooling medium;
A cooling path that connects the exhaust cooler and the internal combustion engine and enables heat exchange between the cooling medium and the internal combustion engine;
Pressure in the exhaust passage on the exhaust gas flow upstream side of the first flow path adjustment mechanism, and pressure in the exhaust gas recirculation passage on the exhaust gas flow upstream side of the second flow path adjustment mechanism; A pressure sensor that detects any one of the pressure of the bypass passage on the exhaust gas flow upstream side of the third flow path adjustment mechanism,
When the temperature of the cooling medium is lower than a predetermined temperature, the first flow path adjustment mechanism, the second flow path adjustment mechanism, and the third flow path adjustment mechanism limit the flow path area of each flow path. And
When the pressure is equal to or higher than a predetermined pressure, the third flow path adjusting mechanism enlarges the flow path area of the bypass passage,
When the pressure is equal to or higher than the predetermined pressure even after the flow passage area of the bypass passage is maximized, the first flow passage adjustment mechanism enlarges the flow passage area of the exhaust passage.
A warming-up system for an internal combustion engine, characterized in that: The third flow path adjusting mechanism increases a flow area of the bypass passage than a flow area of the exhaust passage limited by the first flow path adjusting mechanism.
The warming-up system for an internal combustion engine according to claim 1, wherein: When the temperature of the cooling medium is equal to or higher than the predetermined temperature,
The first flow path adjustment mechanism increases the flow path area of the exhaust passage than when the temperature of the cooling medium is lower than the predetermined temperature.
The warm-up promotion system for an internal combustion engine according to claim 1 or 2, wherein:

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