JP2009024525A - Exhaust gas purification device for internal combustion engine - Google Patents

Abstract

An exhaust emission control device for an internal combustion engine capable of expanding the degree of freedom of fuel addition timing by a fuel addition valve.
An exhaust purification device 20 of an internal combustion engine 10 is applied to an internal combustion engine 10 including a cylinder head 11 in which an exhaust manifold 17 is integrated and a cooling structure 19 for cooling the cylinder head 11. The Further, the exhaust purification device 20 is disposed on the exhaust passage 16 of the internal combustion engine 10 to purify the exhaust, and a fuel addition valve 22 disposed on the upstream side of the catalyst device 21 to add fuel to the exhaust. Is provided. Further, the fuel addition valve 22 is disposed at a position that can be cooled by the cooling structure 19 in the trunk portion 172 of the exhaust manifold 17.
[Selection] Figure 1

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine, and more particularly to an exhaust gas purification apparatus for an internal combustion engine that can expand the degree of freedom of fuel addition timing by a fuel addition valve.

  In recent internal combustion engine exhaust gas purification apparatuses, a configuration in which fuel is added to the exhaust gas is employed in order to promote the exhaust gas purification action of the catalyst device.

  As a conventional exhaust emission control device for an internal combustion engine that employs such a configuration, a technique described in Patent Document 1 is known. A conventional exhaust gas purification device for an internal combustion engine is applied to an internal combustion engine that circulates cooling water that has passed through a radiator in the course of circulating through a cooling water circulation path in the order of a water jacket in a cylinder block and a water jacket in a cylinder head. Exhaust gas in which an exhaust purification catalyst is provided in an exhaust passage connected to a combustion chamber of an internal combustion engine and fuel for promoting an exhaust purification action of the exhaust purification catalyst is added upstream of the exhaust purification catalyst in the exhaust passage. In the exhaust gas purification apparatus for an internal combustion engine provided with a fuel addition valve, the exhaust fuel addition valve is attached to the cylinder head in a state where the injection hole faces the vicinity of the connection portion of the exhaust passage with the combustion chamber, Cooling water before passing through the radiator and flowing into the water jacket in the cylinder block is supplied to the cylinder. And providing a bypass passage for introducing upstream of the exhaust fuel addition valve of the water jacket in the head.

JP 2006-132510 A

  However, in a conventional internal combustion engine exhaust purification device, the fuel addition valve (exhaust fuel addition valve) is attached with its injection hole facing the vicinity of the connection portion (exhaust port) with the combustion chamber of the exhaust passage. There is a problem that the fuel ignition timing is limited by the exhaust timing of the combustion chamber.

  Accordingly, the present invention has been made in view of the above, and an object of the present invention is to provide an exhaust purification device for an internal combustion engine that can expand the degree of freedom of fuel addition timing by a fuel addition valve.

  In order to achieve the above object, an exhaust gas purification apparatus for an internal combustion engine according to the present invention is applied to an internal combustion engine comprising a cylinder head integrated with an exhaust manifold and a cooling structure for cooling the cylinder head. And an exhaust purification device for an internal combustion engine comprising a catalyst device disposed on the exhaust passage of the internal combustion engine for purifying exhaust gas and a fuel addition valve disposed on the upstream side of the catalyst device for adding fuel to the exhaust gas. A portion of the exhaust manifold portion where exhaust from a plurality of combustion chambers gathers in one place is referred to as a collective portion of the exhaust manifold, and a portion downstream of the collective portion and within the cylinder head is exhausted. When called the trunk of the manifold, the fuel addition valve is arranged at a position that is the trunk of the exhaust manifold and can be cooled by the cooling structure. And butterflies.

  In the exhaust purification device of the internal combustion engine, since the fuel addition valve of the exhaust purification device is disposed at the trunk of the exhaust manifold, compared to the configuration in which the fuel addition valve is disposed at the exhaust port of any one combustion chamber, There is an advantage that the degree of freedom (width) of the fuel addition timing by the fuel addition valve is expanded.

  Also, in the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the fuel addition valve injects fuel toward a collection portion of the exhaust manifold.

  In the exhaust manifold assembly, the exhaust flow is complicated due to exhaust interference and the like. Therefore, atomization of the added fuel is promoted by the fuel addition valve injecting the fuel toward the collecting portion of the exhaust manifold. Thereby, there exists an advantage by which the fuel addition to exhaust_gas | exhaustion is performed efficiently.

  In the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the fuel addition valve of the exhaust gas purification apparatus is disposed at the trunk of the exhaust manifold, so that the fuel addition valve is compared with the configuration in which the fuel addition valve is disposed at the exhaust port of any one combustion chamber. Thus, there is an advantage that the degree of freedom (width) of the fuel addition timing by the fuel addition valve is expanded.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

  FIG. 1 is a configuration diagram showing an internal combustion engine 10 and an exhaust purification device 20. FIG. 2 is an explanatory view showing a modification of the exhaust emission control device shown in FIG.

[Internal combustion engine]
The internal combustion engine 10 is, for example, an in-line four-cylinder diesel engine, and is mounted on a vehicle to generate power (see FIG. 1). The internal combustion engine 10 is configured by coupling a cylinder head 11 and a cylinder block (not shown). The cylinder head 11 has a plurality of combustion chambers 12 and an intake port 13 and an exhaust port 14 connected to each combustion chamber 12. The cylinder head 11 is provided with an injector (not shown) for injecting fuel into the combustion chamber 12 and an ignition plug (not shown) for igniting the fuel in the combustion chamber 12 for each combustion chamber 12. . On the other hand, the cylinder block has a cylinder bore (not shown) provided corresponding to each combustion chamber 12 on the cylinder head 11 side. Pistons (not shown) are reciprocally accommodated in these cylinder bores. Each intake port 13 is collected at one place by an intake manifold and connected to an intake passage (intake pipe) 15. Intake air is supplied to each intake port 13 through the intake passage 15 to the internal combustion engine 10. Note that an air filter 151 for removing dust and dirt in the intake air is provided at the inlet of the intake passage 15. Each exhaust port 14 is collected at one place by an exhaust manifold 17 and connected to an exhaust passage (exhaust pipe) 16. Exhaust gas from the internal combustion engine 10 is discharged to the outside through the exhaust passage 16.

  In the internal combustion engine 10, first, intake air is introduced into the combustion chamber 12 (cylinder bore) via the intake passage 15 and the intake port 13 and compressed, and fuel is injected from the injector into the combustion chamber 12 to mix the mixture. Is formed. Next, this air-fuel mixture is ignited by a spark plug and burned in the combustion chamber, and the piston is driven by the combustion energy to reciprocate in the cylinder bore. Then, the reciprocating motion of the piston is converted into the rotational motion of the crankshaft to generate power. Further, the combustion gas in the combustion chamber 12 is discharged to the outside through the exhaust port 14, the exhaust manifold 17 and the exhaust passage 16.

  The internal combustion engine 10 has a supercharger 18 (see FIG. 1). The supercharger 18 realizes high output (or low fuel consumption) of the internal combustion engine 10 by supercharging. The supercharger 18 includes a turbine 181 disposed on the exhaust passage 16, a compressor 182 disposed on the intake passage 15, and a rotating shaft 183 that connects the turbine 181 and the compressor 182. In the supercharger 18, the turbine 181 is driven by the exhaust gas passing through the exhaust passage 16, and the power is transmitted to the compressor 182 via the rotating shaft 183 to drive the compressor 182. The air in the intake passage 15 is compressed by the compressor 182 and supplied (supercharged), so that the output of the internal combustion engine 10 is increased.

  The internal combustion engine 10 has a cooling structure 19 for cooling the cylinder head 11 and the cylinder block (see FIG. 1). The cooling structure 19 includes a refrigerant passage 191 provided in the cylinder head 11 and the cylinder block, and refrigerant supply systems 192 to 194 for supplying refrigerant to the refrigerant passage 191. The refrigerant passage 191 is constituted by, for example, a water jacket provided along the combustion chamber 12, the cylinder bore, and the exhaust port 14. The refrigerant supply systems 192 to 194 include, for example, a pump 193 and a pipe 194 for circulating the cooling water of the radiator 192 to the refrigerant passage 191. In the cooling structure 19, the refrigerant circulates through the refrigerant passage 191, whereby the cylinder head 11 and the cylinder block are cooled, and these thermal damages are suppressed.

  In the internal combustion engine 10, the cylinder head 11 and the exhaust manifold 17 have an integral structure (integrated exhaust manifold) (see FIG. 1). That is, the exhaust manifold 17 is integrally formed with the cylinder head 11, and the exhaust manifold 17 collects a plurality of exhaust ports 14 in one place (the collecting portion 171 of the exhaust manifold 17) in the cylinder head 11. A portion of the exhaust manifold 17 downstream of the collecting portion 171 (the trunk portion 172 of the exhaust manifold 17) and the turbine 181 of the supercharger 18 are connected via the exhaust passage 16. In such a configuration, the exhaust from the plurality of combustion chambers 12 is collected in the collecting portion 171 of the exhaust manifold 17, and the collecting portion 171 is disposed in the cylinder head 11. Therefore, the length of the exhaust passage 16 from the cylinder head 11 (combustion chamber 12) to the turbine 181 is shortened compared to a configuration (not shown) in which the exhaust manifold assembly is outside the cylinder head. In addition, a configuration in which the cylinder head 11 and the turbine 181 are linearly connected via the exhaust passage 16 is possible. Thereby, the pressure loss of exhaust gas is reduced, and the operating efficiency of the supercharger 18 is improved. Note that the collecting portion 171 and the trunk portion 172 of the exhaust manifold 17 are arranged in the cylinder head 11 at a position that can be cooled by the cooling structure 19.

[Exhaust gas purification device]
The exhaust purification device 20 includes a catalyst device 21 and a fuel addition valve 22 (see FIG. 1). The catalyst device 21 has a catalyst for purifying harmful gases (CO, CH, NOx) in the exhaust gas into harmless gases (CO ₂ , H ₂ O, N ₂ ). As such a catalyst, for example, a three-way catalyst (a catalyst in which alumina is coated on the surface of a ceramic carrier and a platinum-rhodium noble metal catalyst material is supported on the surface of the alumina) is employed. The fuel addition valve 22 is a valve for adding (injecting) fuel to the exhaust, and is disposed on the exhaust flow path (downstream of the combustion chamber 12) and upstream of the catalyst device 21. The fuel addition valve 22 is constituted by, for example, a solenoid and a resin component.

  In the exhaust purification device 20, the exhaust from the combustion chamber 12 is purified by the catalyst of the catalyst device 21 and discharged. Further, when the fuel addition valve 22 adds fuel to the exhaust gas from the combustion chamber 12, this fuel serves as a reducing agent to reduce the oxygen concentration in the exhaust gas. Also, hydrocarbon (HC), which is an unburned fuel component, is supplied to the catalyst device 21 by the added fuel. Thereby, the exhaust gas purification action is promoted. Such an exhaust purification device 20 is employed in, for example, a diesel particulate and NOx reduction system (DPNR) of a diesel vehicle.

[Fuel addition valve arrangement]
In the internal combustion engine 10, as described above, the cylinder head 11 and the exhaust manifold 17 have an integral structure (see FIG. 1). Further, the exhaust manifold 17 has a collecting portion 171 that collects exhaust from each combustion chamber 12 in one place, and a trunk portion 172 on the downstream side of the collecting portion 171. Here, the fuel addition valve 22 of the exhaust purification device 20 is disposed in the trunk 172 of the exhaust manifold 17. Further, the trunk 172 is disposed in the cylinder head 11 at a position where it can be cooled by the cooling structure 19. The fuel addition valve 22 may be arranged at any position on the circumference of the trunk 172 of the exhaust manifold 17.

[effect]
In the exhaust purification device 20 of the internal combustion engine 10, (1) since the fuel addition valve 22 of the exhaust purification device 20 is disposed on the trunk 172 of the exhaust manifold 17 (see FIG. 1), any one of the fuel addition valves is combusted. Compared with the configuration arranged in the exhaust port of the chamber, there is an advantage that the degree of freedom (width) of the fuel addition timing by the fuel addition valve 22 is expanded. For example, in a configuration in which the fuel addition valve is disposed in the exhaust port of any one combustion chamber, it is necessary to add fuel to the exhaust from this combustion chamber, so the fuel addition timing is restricted by the exhaust timing in the combustion chamber. Receive. On the other hand, in the above configuration, fuel can be added by the fuel addition valve 22 if the exhaust stroke is performed in any one of the combustion chambers 12.

  Further, (2) the exhaust temperature of the trunk 172 of the exhaust manifold 17 is higher than that of each exhaust port 14. Therefore, the fuel addition valve 22 is disposed on the trunk 172 of the exhaust manifold 17 so that fuel can be added to the high-temperature exhaust. Then, vaporization (evaporation) of the added fuel is promoted, and adhesion of the added fuel to various sensors (for example, a thermosensor) disposed on the exhaust passage is reduced. Thereby, there exists an advantage by which the function of various sensors is ensured appropriately. For example, when liquid fuel adheres to various sensors, carbon or the like adheres to the various sensors using this as a binder. Then, there is a risk that various sensors may malfunction.

  Further, (3) at the time of cold start, since the exhaust gas is at a low temperature, the added fuel is hardly vaporized. In this respect, in this exhaust purification device 20, since the trunk 172 of the exhaust manifold 17 is disposed in the cylinder head 11, fuel can be added to the relatively high temperature exhaust. Thereby, there exists an advantage which can operate the exhaust gas purification apparatus 20 at an early stage also at the time of cold start.

  Further, (4) the existing fuel addition valve is composed of a solenoid and a resin part, so that sufficient cooling is required. In this respect, in this exhaust purification device 20, since the fuel addition valve 22 is disposed at a position that can be cooled by the cooling structure 19 of the cylinder head 11, it is necessary to newly install a cooling structure for cooling the fuel addition valve. There is no. This has the advantage that the cost of the product can be reduced or simplified.

  (5) Since the fuel addition valve 22 is disposed at the trunk portion 172 of the exhaust manifold 17, thermal damage to the fuel addition valve 22 can be prevented as compared with the configuration in which the fuel addition valve is disposed at the collection portion of the exhaust manifold. There are advantages to being. For example, when the engine is in operation, the exhaust manifold assembly is very hot, and if the fuel addition valve is disposed at this position, the fuel addition valve may be thermally damaged.

[Modification]
In the exhaust purification device 20 of the internal combustion engine 10, it is preferable that the fuel addition valve 22 injects fuel toward the collecting portion 171 of the exhaust manifold 17 (see FIG. 2). That is, it is preferable that the fuel addition valve 22 is disposed on the trunk 172 of the exhaust manifold 17 (on the downstream side and in the vicinity of the collecting portion 171), and the fuel injection direction is directed to the collecting portion 171 of the exhaust manifold 17.

  In the collective portion 171 of the exhaust manifold 17, the exhaust flow is complicated due to exhaust interference and the like. Therefore, when the fuel addition valve 22 injects fuel toward the collecting portion 171 of the exhaust manifold 17, atomization of the added fuel is promoted. Thereby, there exists an advantage by which the fuel addition to exhaust_gas | exhaustion is performed efficiently.

  Further, in the exhaust purification device 20 of the internal combustion engine 10, the fuel addition valve 22 is disposed on the trunk 172 of the exhaust manifold 17 as described above (see FIG. 1). However, the present invention is not limited to this, and the fuel addition valve 22 may be disposed in the collecting portion 171 of the exhaust manifold 17 (not shown). Thereby, there is an advantage that the fuel is added to the exhaust gas more efficiently.

  As described above, the exhaust gas purification apparatus for an internal combustion engine according to the present invention is useful in that the degree of freedom of fuel addition timing by the fuel addition valve can be expanded.

It is a block diagram which shows an internal combustion engine and an exhaust gas purification apparatus. It is explanatory drawing which shows the modification of the exhaust gas purification apparatus described in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 11 Cylinder head 12 Combustion chamber 13 Intake port 14 Exhaust port 15 Intake passage 151 Air filter 16 Exhaust passage 17 Exhaust manifold 171 Collecting part 172 Trunk part 18 Supercharger 181 Turbine 182 Compressor 183 Rotating shaft 19 Cooling structure 191 Refrigerant path 192 Radiator 193 Pump 194 Piping 20 Exhaust purification device 21 Catalytic device 22 Fuel addition valve

Claims (2)

A catalytic device applied to an internal combustion engine comprising a cylinder head integrated with an exhaust manifold and a cooling structure for cooling the cylinder head, and disposed on an exhaust passage of the internal combustion engine to purify exhaust gas And an exhaust purification device for an internal combustion engine comprising a fuel addition valve arranged on the upstream side of the catalyst device to add fuel to the exhaust,
A portion of the exhaust manifold portion where exhaust from a plurality of combustion chambers gathers at one place is referred to as a collective portion of the exhaust manifold, and a portion downstream of the collective portion and within the cylinder head is a portion of the exhaust manifold. When we call executives
An exhaust gas purification apparatus for an internal combustion engine, wherein the fuel addition valve is disposed at a position that is a trunk portion of an exhaust manifold and can be cooled by the cooling structure.   The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the fuel addition valve injects fuel toward a collecting portion of the exhaust manifold.

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