JP2010203412A - Exhaust cooling structure of internal combustion engine and control device of exhaust cooling structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust cooling structure of an internal combustion engine capable of properly cooling exhaust gas when necessary, and a control device of the exhaust cooling structure of the internal combustion engine for controlling the exhaust cooling structure of the internal combustion engine. <P>SOLUTION: An exhaust lubricating structure 10 has a cylinder head 52 having first and second exhaust ports 522 and 523 at one cylinder, a first exhaust valve 53 for opening and closing the first exhaust port 522 and a second exhaust valve 54 for opening and closing the second exhaust port 523, and a variable valve train 55 capable of stopping the operation of one exhaust valve among the first and second exhaust valves 53 and 54. The cylinder head 52 has a part for forming a second water jacket 521 as a cooling means for cooling the first exhaust port 522 in a larger degree than the second exhaust port 523 by cooling water. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention controls an exhaust cooling structure of an internal combustion engine provided with a cooling means for cooling an exhaust port with a refrigerant and a single valve pause mechanism capable of performing a single valve pause operation, and the exhaust cooling structure of the internal combustion engine. The present invention relates to a control device for an exhaust cooling structure of an internal combustion engine.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, a technique for cooling exhaust gas with a refrigerant such as cooling water of an internal combustion engine is known. The cylinder head of the internal combustion engine disclosed in Patent Document 1 has an exhaust manifold integrally formed, and has a structure capable of cooling the exhaust manifold with cooling water flowing through the cylinder head. In addition, for example, Patent Document 2 discloses a technique that is considered to be related to the present invention in that a variable valve mechanism that can perform a one-valve pause operation is disclosed.

JP 2007-309189 A JP 2008-95668 A

  By the way, the exhaust gas of the internal combustion engine is purified by the catalyst in the active state. For example, since the catalyst is not activated at the time of engine cold start, generally the catalyst is warmed up by exhaust gas so as to activate the catalyst early. Yes. In contrast, the cylinder head of the internal combustion engine disclosed in Patent Document 1 has a structure in which the cooling water flowing through the cylinder head cools the exhaust manifold, and the cooling water flowing through the cylinder head is generally used during engine operation. It is always in circulation. For this reason, in the cylinder head of the internal combustion engine disclosed in Patent Document 1, the exhaust gas is cooled by the cooling water even when the engine is cold start, and as a result, there is a problem in that activation of the catalyst may be delayed. there were.

  Accordingly, the present invention has been made in view of the above problems, and an exhaust cooling structure of an internal combustion engine capable of appropriately performing exhaust cooling as needed, and an internal combustion engine that controls the exhaust cooling structure of the internal combustion engine. An object of the present invention is to provide a control device for an exhaust cooling structure of an engine.

  An exhaust cooling structure for an internal combustion engine according to the present invention for solving the above-mentioned problems includes a cylinder head provided with first and second exhaust ports for each cylinder, and a first for opening and closing the first exhaust port. One-valve pause capable of stopping the operation of one of the exhaust valve, the second exhaust valve that opens and closes the second exhaust port, and the first and second exhaust valves Either one of the first and second exhaust ports is cooled by the mechanism and the refrigerant, or one of the first and second exhaust ports is replaced with the other. Cooling means for cooling to a greater degree than the exhaust port.

  In the present invention, the cooling means cools the first exhaust port with a refrigerant or cools the first exhaust port to a greater degree than the second exhaust port. The two exhaust cylinders are provided such that each of the first exhaust ports provided for each of the two cylinders is provided adjacent to each other, and an oil passage is provided between each of the first exhaust ports. It is preferable.

  The present invention is also a control device for an exhaust cooling structure of an internal combustion engine that controls the exhaust cooling structure of the internal combustion engine according to claim 1 or 2, wherein the one-valve pause mechanism is a control target, and the first and second The exhaust port is provided with control means for performing control to change the exhaust port through which the exhaust gas is circulated according to the engine operating state.

  According to the present invention, the exhaust can be appropriately cooled as necessary.

1 is a diagram schematically showing, in section, an internal combustion engine 50 including an exhaust cooling structure (hereinafter simply referred to as an exhaust cooling structure) 10 for an internal combustion engine together with an intake system 20 and an exhaust system 30. FIG. In FIG. 1, the second water jacket 521 is not shown. 2 is a diagram schematically showing a cooling system of an internal combustion engine 50. FIG. 4 is a perspective view schematically showing a core 80 of a cylinder head 52 that forms a second water jacket 521. FIG. It is the figure which looked at the core 80 from the exhaust side. 3 is a top view of the core 80. FIG. In FIG. 5, the first and second exhaust ports 522 and 523 formed in the cylinder head 52 and the oil flow path 524 are simultaneously shown in correspondence with the core 80. 1 is a diagram schematically showing a control device for an exhaust cooling structure of an internal combustion engine realized by an ECU (Electronic Control Unit) 1. FIG. It is a figure which shows operation | movement of ECU1 with a flowchart.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings.

An internal combustion engine 50 having an exhaust cooling structure 10 will be described with reference to FIGS. The internal combustion engine 50 has an in-line 4-cylinder arrangement structure. As shown in FIG. 1, the internal combustion engine 50 includes a cylinder block 51, a cylinder head 52, a first exhaust valve 53, a second exhaust valve 54, and a variable valve mechanism (ExVVT) 55. .
Air is supplied to the internal combustion engine 50 via the intake system 20. The intake system 20 includes an air cleaner 21, an air flow meter 22, an electronic control throttle 23, and an intake manifold 24. The air cleaner 21 filters the intake air. The air flow meter 22 measures the intake air amount GA of the internal combustion engine 50 and detects the intake air temperature. The electronic control throttle 23 adjusts the intake air amount GA. The intake manifold 24 distributes intake air to each cylinder of the internal combustion engine 50.
In the internal combustion engine 50, combustion of a mixture of intake air and fuel is performed. The gas generated by the combustion is exhausted through the exhaust system 30. The exhaust system 30 includes an exhaust manifold 31 and a catalyst 32. The exhaust manifold 31 joins the exhaust from each cylinder of the internal combustion engine 50. The catalyst 32 purifies the exhaust when it is in an active state.

  As shown in FIG. 2, the cylinder block 51 is provided with a first water jacket 511, and the cylinder head 52 is provided with a second water jacket 521. The first water jacket 511 has an inlet connected to the water pump 56 and an outlet connected to the second water jacket 521. The second water jacket 521 is formed by the core 80 of the cylinder head 52 shown in FIGS. The second water jacket 521 includes a cooling water inlet 513a. The cooling water inlet 513 a is formed on one end side of the cylinder head 52 in the cylinder arrangement direction, and is formed by the first protrusion 81.

  The second water jacket 521 includes a cooling water discharge port 513b. The cooling water discharge port 513 b is formed on the other end side of the cylinder head 52 in the cylinder arrangement direction, and is formed by the second protrusion 82. The cooling water discharge port 513b is branched and connected to a radiator 60, a thermostat 61, and a heater core 62 of an air conditioner (not shown) (not shown) via a cooling water pipe. The radiator 60 is connected to a thermostat 61 on the downstream side via a cooling water pipe, and the thermostat 61 is connected to a water pump 56 on the downstream side. The heater core 62 is connected to the water pump 56 on the downstream side.

  The water pump 56 is a mechanical water pump that is driven by the output of the internal combustion engine 50. For this reason, in the internal combustion engine 50, the cooling water is constantly circulated during engine operation. Specifically, when the water pump 56 pumps the cooling water, the pumped cooling water flows through the first and second water jackets 511 and 521, then flows into the thermostat 61 and the heater core 62, and then returns to the water pump 56. . At this time, when the temperature of the cooling water is higher than the set temperature of the thermostat 61, the circulation of the cooling water via the radiator 60 is further permitted.

  Then, when circulating through the first and second water jackets 511 and 521, the cooling water is received, whereby the cylinder block 51 and the cylinder head 52 are cooled. On the other hand, the radiator 60 dissipates cooling water, thereby recovering the cooling performance. In the heater core 62, heat is exchanged between the cooling water and the air, thereby warming the air. And it can utilize as heating by blowing the warmed air in a vehicle interior.

  In addition to the second water jacket 521, the cylinder head 52 is provided with a first exhaust port 522, a second exhaust port 523, and an oil flow path 524. The first and second exhaust ports 522 and 523 constitute two exhaust ports provided per cylinder. The first exhaust port 522 is disposed between two adjacent cylinders of the # 1 and # 2 cylinders, and adjacent to the # 3 and # 4 cylinders, as shown in FIG. The two cylinders are provided so as to be adjacent to each other. The oil flow path 524 is provided between each of the two first exhaust ports 522 provided so as to be adjacent to each other, as shown in FIG. The oil flow path 524 is a passage for returning oil to an oil pan (not shown) by dropping its own weight.

  Specifically, the second water jacket 521 has a portion formed around the first exhaust port 522 and a portion formed around the second exhaust port 523. More specifically, the portion of the second water jacket 521 formed around the first exhaust port 522 is larger than the portion formed around the second exhaust port 523. In this respect, in the core 80, the portion 83 corresponding to the first exhaust port 522 protrudes more along the exhaust port extending direction than the portion 84 corresponding to the second exhaust port 523. The second water jacket 521 may be configured to cool only the first exhaust port 522 out of the first and second exhaust ports 522 and 523.

  The cooling water flowing through the second water jacket 521 cools the first and second exhaust ports 522 and 523, thereby cooling the exhaust flowing through the first and second exhaust ports 522 and 523. . The second water jacket 521 formed as described above cools the first exhaust port 522 to a greater degree than the second exhaust port 523. In the present embodiment, the cooling means is realized in the portion of the cylinder head 52 where the second water jacket 521 is formed, and the cylinder head 52 includes the cooling means.

  The first and second exhaust valves 53 and 54 constitute two exhaust valves provided per cylinder. The first exhaust valve 53 opens and closes the first exhaust port 522, and the second exhaust valve 54 opens and closes the second exhaust port 523. The variable valve mechanism 55 is a mechanism that makes the valve characteristics (for example, valve timing and operating angle) of the first and second exhaust valves 53 and 54 variable. The variable valve mechanism 55 is a mechanism capable of a one-valve pause operation in which the operation of one of the first and second exhaust valves 53 and 54 is stopped in a closed state. Specifically, such a variable valve mechanism 55 can be realized by applying, for example, a structure similar to the structure that enables the one-valve rest operation by the variable valve mechanism disclosed in Patent Document 2 described above. . In this embodiment, the variable valve mechanism 55 realizes a one-valve pause mechanism.

  As shown in FIG. 6, the ECU 1 includes a microcomputer including a CPU 2, a ROM 3, a RAM 4, and the like, and input / output circuits 5 and 6. The CPU 2, ROM 3, RAM 4, and input / output circuits 5 and 6 are connected to each other via a bus 7. The ECU 1 is mainly configured to control the internal combustion engine 50. Specifically, the ECU 1 is configured to control, for example, a variable valve mechanism 55 and a fuel injection valve of an internal combustion engine 50 (not shown). The variable valve mechanism 55 and the fuel injection valve are electrically connected to the ECU 1 as control targets.

  Various sensors such as an air flow meter 22, a water temperature sensor 71, and a crank angle sensor 72 are electrically connected to the ECU 1. The intake air amount GA of the internal combustion engine 50 is based on the output of the air flow meter 22, the coolant temperature THW of the internal combustion engine 50 is based on the output of the water temperature sensor 71, and the rotational speed NE of the internal combustion engine 50 is based on the output of the crank angle sensor 72. Each is detected by ECU1. The load factor KL of the internal combustion engine 50 is calculated by the ECU 1 based on the detected rotational speed NE and intake air amount GA.

  The ROM 3 is configured to store programs, map data, and the like in which various processes executed by the CPU 2 are described. When the CPU 2 executes processing while using the temporary storage area of the RAM 4 as necessary based on the program stored in the ROM 3, the ECU 1 has various control means, determination means, detection means, calculation means, and the like. To be realized. In this regard, the ECU 1 functions as a control unit that controls the variable valve mechanism 55 as a control target, and controls the first and second exhaust ports 522 and 523 to change the exhaust port through which the exhaust flows according to the engine operating state. Is realized.

Specifically, this control means closes the operation of the first exhaust valve 53, for example, when the engine is cold and when there is no operation request of a heater that receives heat from the exhaust and exchanges heat with the air. The variable valve mechanism 55 is controlled so as to be stopped in the valve state. Further, this control means is realized to control the variable valve mechanism 55 so that the operation of the second exhaust valve 54 is stopped in the closed state when the engine is cold and when there is a heater operation request. Further, this control means is a variable valve mechanism 55 so that the operation of the second exhaust valve 54 is stopped in the closed state when the engine is warm and the engine operation state is an operation state of high load and high rotation. It is realized to control. Further, the control means is a variable valve mechanism that permits the operation of the first and second exhaust valves 53 and 54 when the engine is warm and the engine operation state is not an operation state of high load and high rotation. 55 is controlled.
In this embodiment, the exhaust cooling structure 10 is realized by the cylinder head 52, the first and second exhaust valves 53 and 54, and the variable valve mechanism 55.

  Next, the operation of the ECU 1 will be described with reference to the flowchart shown in FIG. Note that the processing shown in this flowchart is repeatedly executed at a very short time interval during operation of the internal combustion engine 50. The ECU 1 determines whether or not the water temperature THW is equal to or lower than a predetermined value T (for example, 75 ° C.) (step S1). In this step, it is determined whether or not the engine is cold. If the determination in step S11 is affirmative, it is determined that the engine is cold. At this time, the ECU 1 determines whether there is a heater operation request (whether the heater is ON) (step S2). . If a negative determination is made in step S2, the process proceeds to step S3, and the ECU 1 controls the variable valve mechanism 55 so that the operation of the first exhaust valve 53 is stopped in the closed state (the first exhaust valve 53 is closed). Thereby, since the exhaust gas flows through the second exhaust port 523, the cooling of the exhaust gas is suppressed. Accordingly, this enables early activation of the catalyst.

  On the other hand, if an affirmative determination is made in step S2, the process proceeds to step S4, where the ECU 1 controls the variable valve mechanism 55 so as to pause the operation of the second exhaust valve 54 in the closed state (second exhaust valve 54 closed). . As a result, the exhaust gas flows through the first exhaust port 522, so that the amount of heat received by the cooling water increases. Therefore, the performance of the heater can be ensured by this. After step S3 or S4, this flowchart is once ended. After that, while the water temperature THW is equal to or lower than the predetermined value T, an affirmative determination is made in step S1, and when the water temperature THW becomes higher than the predetermined value T, a negative determination is made in step S1.

  If a negative determination is made in step S1, it is determined that the engine is warm. At this time, the ECU 1 determines whether or not the load factor KL is equal to or greater than the predetermined value X% and the rotational speed NE is equal to or greater than the predetermined value Y (step S5). In this step, it is determined whether or not the engine operation state is an operation state of high load and high rotation. If a negative determination is made in step S5, it is determined that the engine operation state is not a high load high rotation operation state, and the process proceeds to step S6. At this time, the ECU 1 controls the variable valve mechanism 55 so as to permit the operation of the first and second exhaust valves 53, 54 (first and second exhaust valves 53, 54 open). As a result, the first and second exhaust valves 53 and 54 normally operate when the engine is warm.

  On the other hand, if an affirmative determination is made in step S5, it is determined that the engine operating state is an operating state of high load and high rotation, and the process proceeds to step S4. At this time, the ECU 1 controls the variable valve mechanism 55 so that the operation of the second exhaust valve 54 is stopped in the closed state (the second exhaust valve 54 is closed). As a result, the exhaust gas flows through the first exhaust port 522, so that cooling of the exhaust gas is promoted. Therefore, it is possible to prevent or suppress the catalyst from being overheated by high-temperature exhaust gas, and to improve the fuel efficiency of the internal combustion engine 50 when operating at an excess air ratio λ = 1. Specifically, according to the ECU 1, it is possible to appropriately cool the exhaust as necessary in this way.

In addition, when cooling the exhaust using cooling water flowing through the cylinder head 52, it is generally difficult to individually adjust the flow rate of the flowing cooling water for each part of the cylinder head 52, for example. It is usually difficult to perform proper cooling as needed. On the other hand, the exhaust cooling structure 10 is preferable in that the exhaust can be appropriately cooled as necessary.
Further, according to the exhaust cooling structure 10 in which the oil flow path 524 is provided between the two first exhaust ports 522 having a large degree of cooling, it is possible to simultaneously promote the cooling of the oil falling by its own weight on the oil pan.
As described above, the exhaust cooling structure 10 and the ECU 1 can appropriately perform the cooling of the exhaust as necessary, and can further promote the cooling of the oil at the same time.

The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.
For example, in the above-described embodiment, the case of the internal combustion engine 50 having the in-line four-cylinder arrangement structure has been described in detail, but the present invention may be applied to an appropriate internal combustion engine.
In addition, it is reasonable to realize the control means mainly by the ECU 1 that controls the internal combustion engine 50. However, the control means may be realized by hardware such as other electronic control devices or dedicated electronic circuits, or a combination thereof. . In this regard, the control device for the exhaust cooling structure of the internal combustion engine of the present invention is realized by, for example, a plurality of electronic control devices, hardware such as electronic circuits, or a combination of electronic control devices and hardware such as electronic circuits. Also good. Similarly, various means functionally realized by the control device for the exhaust cooling structure of the internal combustion engine of the present invention include a plurality of electronic control devices, hardware such as electronic circuits, and hardware such as electronic control devices and electronic circuits. It may be realized in combination with wear.

1 ECU
DESCRIPTION OF SYMBOLS 10 Exhaust cooling structure 22 Air flow meter 32 Catalyst 50 Internal combustion engine 52 Cylinder head 521 2nd water jacket 522 1st exhaust port 523 2nd exhaust port 524 Oil flow path 53 1st exhaust valve 54 2nd exhaust valve 55 Variable valve mechanism 56 Water pump 60 Radiator 61 Thermostat 62 Heater core 80 Core

Claims (3)

A cylinder head provided with first and second exhaust ports per cylinder;
A first exhaust valve that opens and closes the first exhaust port; and a second exhaust valve that opens and closes the second exhaust port;
A one-valve pause mechanism capable of stopping the operation of one of the first and second exhaust valves;
Either one of the first and second exhaust ports is cooled by the refrigerant, or one of the first and second exhaust ports is used as the other exhaust port. An exhaust cooling structure for an internal combustion engine comprising cooling means for cooling to a greater degree. An exhaust cooling structure for an internal combustion engine according to claim 1,
When the cooling means cools the first exhaust port with a refrigerant or cools the first exhaust port to a greater degree than the second exhaust port,
An internal combustion engine in which at least two adjacent cylinders are provided adjacent to each of the first exhaust ports provided for each of the two cylinders, and an oil flow path is provided between each of the first exhaust ports. Engine exhaust cooling structure. An exhaust cooling structure control apparatus for an internal combustion engine that controls the exhaust cooling structure for an internal combustion engine according to claim 1 or 2,
An exhaust cooling structure for an internal combustion engine comprising control means for controlling the one-valve stop mechanism to change an exhaust port for circulating exhaust gas according to an engine operating state for the first and second exhaust ports. Control device.

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