WO2017170162A1

WO2017170162A1 - Cooling device

Info

Publication number: WO2017170162A1
Application number: PCT/JP2017/011817
Authority: WO
Inventors: 智洋藤原; 岳司小野塚; 良太阿南; 隆太池原
Original assignee: いすゞ自動車株式会社
Priority date: 2016-03-29
Filing date: 2017-03-23
Publication date: 2017-10-05
Also published as: JP2017180166A; CN109072746A

Abstract

This invention is provided with: an exhaust pipe injector 40 provided to an exhaust pipe 12 of an engine 10, the exhaust pipe injector 40 capable of injecting fuel into the exhaust pipe 12; a fuel supply piping 41 for supplying the fuel to the exhaust pipe injector 40; and a heat exchanger unit 50 for channeling cooling water to the outer peripheral surface of at least a part of the fuel supply piping 41, causing the fuel in the fuel supply piping 41 to exchange heat with the cooling water, and cooling the fuel.

Description

Cooling system

The present disclosure relates to a cooling device, and more particularly, to cooling of an injection system of an exhaust pipe injector.

In general, in an exhaust passage of an engine, an oxidation catalyst that oxidizes hydrocarbons (HC) and carbon monoxide (CO) in exhaust gas, a filter that collects particulate matter (PM), a nitrogen compound (NOx) NOx catalyst or the like is provided.

Since there is an upper limit to the PM collection capacity of the filter, when the amount of accumulated PM reaches a predetermined amount, it is necessary to perform so-called filter regeneration that burns and removes the accumulated PM. Similarly, since the storage capacity of the NOx catalyst is limited, when the NOx storage amount reaches a predetermined amount, it is necessary to perform so-called catalyst regeneration that purges NOx. In these filter regeneration and catalyst regeneration (hereinafter simply referred to as regeneration), unburnt fuel is injected into the exhaust pipe from the exhaust pipe injector, and the exhaust temperature is raised to the PM combustion temperature or purge temperature by the oxidation reaction heat generated in the oxidation catalyst. Done in

Since the exhaust pipe injector used for such regeneration is exposed to high-temperature exhaust heat in the exhaust pipe, there is a problem that clogging occurs when burning or deposits are accumulated. For this reason, various structures for preventing clogging have been proposed by forming a water jacket that circulates cooling water around the exhaust pipe injector and suppressing the temperature rise of the exhaust pipe injector (for example, Patent Documents). 1).

Japanese Unexamined Patent Publication No. 2010-031769

By the way, during the regeneration interval (between the end of regeneration and the start of the next regeneration), the fuel stays in the fuel supply pipe that supplies fuel to the exhaust pipe injector. The fuel supply pipe may be extended adjacent to an exhaust manifold or an exhaust pipe having a high temperature atmosphere due to layout restrictions in the engine room.

For this reason, if the fuel in the fuel supply pipe deteriorates due to the high-temperature exhaust heat emitted from the exhaust manifold or exhaust pipe and flows into the nozzle of the exhaust pipe injector, it clogs or malfunctions by blocking the injection holes. There is a problem that causes That is, there is a possibility that clogging or malfunction of the exhaust injector cannot be sufficiently prevented only by cooling the periphery of the exhaust pipe injector as in the above-described prior art.

The technology of the present disclosure aims to effectively prevent clogging of the exhaust pipe injector.

The disclosed technique is provided in an exhaust pipe of an engine, an exhaust pipe injector capable of injecting fuel into the exhaust pipe, a fuel supply pipe for supplying fuel to the exhaust pipe injector, and at least a part of the fuel supply pipe And a heat exchanging part that cools the fuel in the fuel supply piping by exchanging heat with the cooling water.

The heat exchanging portion is formed with a diameter larger than that of the fuel supply pipe, and includes an outer pipe through which the fuel supply pipe is inserted, and an inner peripheral surface of the outer pipe and the fuel supply pipe You may distribute | circulate the said cooling water between outer peripheral surfaces.

The flow of cooling water in the heat exchange part may be opposite to the fuel supply direction in the fuel supply pipe.

At least a part of the fuel supply pipe is arranged adjacent to at least one of the exhaust pipe or the exhaust manifold of the engine, and the heat exchange part is a part of the fuel supply pipe adjacent to the exhaust pipe or the exhaust manifold. May be provided.

A second heat exchanging part may be further provided which is formed in an annular shape surrounding the outer periphery of the nozzle part of the exhaust pipe injector and in which cooling water flows.

The cooling water may be supplied from a cooling water circulation circuit of the engine.

According to the technology of the present disclosure, clogging of the exhaust pipe injector can be effectively prevented.

It is a typical whole lineblock diagram showing the cooling device concerning a first embodiment of this indication. It is a typical sectional view showing the heat exchange part concerning a first embodiment of this indication. It is a typical sectional view showing the heat exchange part concerning a first embodiment of this indication. It is a typical whole block diagram which shows the cooling device which concerns on 2nd embodiment of this indication. It is a typical block diagram which shows the heat exchange part which concerns on 3rd embodiment of this indication. It is a typical block diagram which shows the heat exchange part which concerns on 3rd embodiment of this indication.

Hereinafter, a cooling device according to each embodiment of the present disclosure will be described with reference to the accompanying drawings. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First embodiment]
FIG. 1 is a schematic overall configuration diagram showing a cooling device 1A according to the first embodiment. An exhaust pipe 12 for leading exhaust gas is connected to an exhaust manifold 11 of a diesel engine (hereinafter simply referred to as an engine) 10. The exhaust pipe 12 is provided with an exhaust pipe injector 40, an oxidation catalyst 13, a filter 14, a NOx catalyst (not shown) and the like in order from the exhaust upstream side.

The cooling water circulation circuit 20 includes a water jacket 21 that cools each cylinder of the engine 10, a first cooling water pipe 23 that connects an outlet portion of the water jacket 21 and an inlet portion of the radiator 22, and an inlet portion of the water jacket 21. The cooling water pump 24 provided, the 2nd cooling water piping 25 which connects the exit part of the radiator 22, and the cooling water pump 24, the bypass cooling water piping 26 which bypasses the radiator 22, and the thermostat 27 are provided. . When the cooling water temperature reaches a predetermined warm-up temperature, the thermostat 27 is opened, and the flow path of the cooling water is switched from the bypass cooling water pipe 26 to the radiator 22.

In the present embodiment, the cooling water circulation circuit 20 branches from the first cooling water pipe 23 and introduces a cooling water introduction pipe 29A for introducing the cooling water into the heat exchanging section 50, and a cooling water introduction pipe 29A for the first cooling water pipe 23. And a cooling water outlet pipe 29 </ b> B that joins the cooling water downstream from the branching section and returns the cooling water from the heat exchange section 50 to the first cooling water pipe 23. Details of the heat exchange unit 50 will be described later.

The fuel injection device 30 includes a fuel tank 31 that stores fuel, a common rail 32 that accumulates high-pressure fuel, an in-cylinder injector 33 that injects fuel supplied from the common rail 32 into each cylinder, and an upstream side of the oxidation catalyst 13. An exhaust pipe injector 40 that injects fuel into the exhaust pipe 12 on the side, a first fuel supply pipe 34 that connects the fuel tank 31 and the common rail 32, and a first fuel supply pipe 34. A feed pump 35 that pumps fuel from the fuel, a first high-pressure pump 36 that is interposed in the first fuel supply pipe 34 and pressurizes the fuel pumped up by the feed pump 35, and the feed pump 35 and the first high-pressure pump 36. A second fuel supply pipe 41 branched from the first fuel supply pipe 34 and supplying fuel to the exhaust pipe injector 40; It is interposed in the supply pipe 41, and a second high pressure pump 42 which pressurizes the fuel pumped up by the feed pump 35.

In the present embodiment, in the second fuel supply pipe 41 adjacent to the exhaust pipe 12 or the exhaust manifold 11 that generates high-temperature exhaust heat, the heat that cools the fuel in the second fuel supply pipe 41 by heat exchange with cooling water. An exchange unit 50 is provided.

Next, based on FIG. 2A and FIG. 2B, the detailed structure of the heat exchange part 50 which concerns on this embodiment is demonstrated.

The heat exchanging unit 50 has a hollow cylindrical cooling pipe 51 having an inner diameter larger than the outer diameter of the second fuel supply pipe 41, and a cylinder protruding in the radial direction from the outer peripheral surface on one end side of the cooling pipe 51. A cooling water inlet 52 having a protruding end connected to the cooling water introduction pipe 29A, and a cylindrical shape protruding radially from the outer peripheral surface of the other end of the cooling pipe 51. And a cooling water outlet 53 having a cooling water outlet pipe 29B connected to the end thereof.

A second fuel supply pipe 41 is inserted through the cooling pipe 51 in the cylindrical axis direction. That is, the heat exchanging unit 50 has a double pipe structure in which the second fuel supply pipe 41 is an inner pipe and the cooling pipe 51 is an outer pipe. A predetermined clearance is ensured over the entire circumference between the inner peripheral surface of the cooling pipe 51 and the outer peripheral surface of the second fuel supply pipe 41, and the second fuel supply inserted into the cooling pipe 51. Cooling water is made to flow uniformly over the entire outer peripheral surface of the pipe 41.

The cooling water inlet 52 is preferably provided on the downstream side of the second fuel supply pipe 41 in the fuel supply direction with respect to the cooling water outlet 53. That is, the cooling water flows in the cooling pipe 51 in the opposite direction with respect to the fuel supply direction in the second fuel supply pipe 41.

As described above in detail, according to the cooling device 1A of the present embodiment, the second fuel supply pipe adjacent to the exhaust pipe 12 and the exhaust manifold 11 in the cooling pipe 51 to which the cooling water is supplied from the cooling water circulation circuit 20. The fuel in the second fuel supply pipe 41 is cooled by the cooling water flowing between the cooling pipe 51 and the second fuel supply pipe 41 because the heat exchanging part 50 is made to have a double pipe structure. It is configured as follows. In this way, by circulating the cooling water on the outer peripheral surface of the second fuel supply pipe 41 exposed to the high temperature atmosphere in the vicinity of the exhaust pipe 12 and the exhaust manifold 11, in particular, in the second fuel supply pipe 41 during the regeneration interval. Deterioration of the staying fuel is effectively suppressed, and clogging of the exhaust pipe injector 40 can be prevented.

In addition, since the flow of the cooling water in the cooling pipe 51 is reversed with respect to the fuel supply direction in the second fuel supply pipe 41, the temperature is easily increased in the second fuel supply pipe 41 on the downstream side ( The low-temperature cooling water before heat exchange hits the fuel on the exhaust pipe injector 40 side), and the cooling efficiency of the fuel can be reliably improved.

In the first embodiment, the position where the heat exchanging unit 50 is provided is not limited to the vicinity of the exhaust pipe 12 or the exhaust manifold 11, and the second fuel supply such as the vicinity of a turbocharger housing or EGR pipe (not shown) is used. The pipe 41 may be provided in another part exposed to a high temperature atmosphere. The number of heat exchange units 50 may be plural.

[Second Embodiment]
Next, based on FIG. 3, the detailed structure of the cooling device 1B which concerns on 2nd embodiment is demonstrated. The cooling device 1 </ b> B of the second embodiment further includes a second heat exchange unit 60 in series with the heat exchange unit 50. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

The second heat exchange unit 60 includes an annular cooling water channel 61 that surrounds the outer periphery of the nozzle portion of the exhaust pipe injector 40, a cooling water inlet unit 62 that introduces cooling water into the cooling water channel 61 from the cooling water introduction pipe 29A, A cooling water outlet part 63 for deriving cooling water from the inside of the cooling water channel 61 and a cooling water connection pipe 64 for connecting the cooling water outlet part 63 and the cooling water inlet part 52 of the cooling pipe 51 are provided.

That is, the cooling water introduced into the cooling water flow path 61 from the cooling water circulation circuit 20 via the cooling water introduction pipe 29A cools the nozzle portion of the exhaust pipe injector 40, and then the cooling pipe 51 via the cooling water connection pipe 64. The fuel is introduced into the second fuel supply pipe 41 so as to cool the fuel. Thus, the fuel in the second fuel supply pipe 41 exposed to the high temperature atmosphere in the vicinity of the exhaust pipe 12 and the exhaust manifold 11 while cooling the nozzle portion of the exhaust pipe injector 40 exposed to the high temperature exhaust gas in the exhaust pipe 12. Also, the exhaust pipe injector 40 can be reliably prevented from being clogged by cooling.

In the second embodiment, the order in which the cooling water is supplied is not limited to the order from the second heat exchanging unit 60 to the heat exchanging unit 50, but is supplied in the order from the heat exchanging unit 50 to the second heat exchanging unit 60. You may comprise. Moreover, these two

heat exchange parts

50 and 60 may be arrange | positioned in parallel, and it may be comprised so that cooling water may be separately supplied from the cooling water circulation circuit 20 to each

heat exchange part

50 and 60.

[Third embodiment]
Next, based on FIG. 4A and FIG. 4B, the detailed structure of 1 C of cooling devices which concern on 3rd embodiment is demonstrated. The cooling device 1C of the third embodiment is obtained by modifying the shape of the heat exchange unit 50 in the first or second embodiment. The other components are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 4A, the heat exchange unit 50 of the third embodiment contacts the second fuel supply pipe 41 and the cooling pipe 51 without penetrating the second fuel supply pipe 41 into the cooling pipe 51. In this state, they are arranged in parallel. Alternatively, as shown in FIG. 4B, the cooling pipe 51 </ b> B is spirally wound around the outer peripheral surface of the second fuel supply pipe 41.

In any of these structures, the outer peripheral surface of the cooling pipe 51 is in line contact with the outer peripheral surface of the second fuel supply pipe 41, and the fuel in the second fuel supply pipe 41 is cooled by the cooling water flowing in the cooling pipe 51. Thus, clogging of the exhaust pipe injector 40 can be effectively prevented.

[Others]
Note that the present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

For example, although the cooling water has been described as being supplied from the cooling water circulation circuit 20 of the engine 10, the cooling water may be supplied from another cooling water circuit separate from the cooling water circulation circuit 20. The engine 10 is not limited to a diesel engine, and can be widely applied to other engines such as a gasoline engine.

This application is based on a Japanese patent application filed on March 29, 2016 (Japanese Patent Application No. 2016-065348), the contents of which are incorporated herein by reference.

The cooling device according to the present disclosure is useful in that the exhaust pipe injector can be effectively prevented from being clogged.

1A, B, C Cooling device 10 Engine 11 Exhaust manifold 12 Exhaust pipe 20 Cooling water circulation circuit 23 First cooling water pipe 29A Cooling water introduction pipe 29B Cooling water outlet pipe 40 Exhaust pipe injector 41 Second fuel supply pipe 42 High pressure pump 50 Heat Replacement part 51 Cooling pipe 52 Cooling water inlet part 53 Cooling water outlet part

Claims

An exhaust pipe injector provided in the exhaust pipe of the engine and capable of injecting fuel into the exhaust pipe;
A fuel supply pipe for supplying fuel to the exhaust pipe injector;
A cooling device, comprising: a heat exchanging unit that circulates cooling water on at least a part of the outer peripheral surface of the fuel supply pipe and cools the fuel in the fuel supply pipe by exchanging heat with the cooling water.
The heat exchanging portion is formed with a diameter larger than that of the fuel supply pipe, and includes an outer pipe through which the fuel supply pipe is inserted, and an inner peripheral surface of the outer pipe and the fuel supply pipe The cooling device according to claim 1, wherein the cooling water is circulated between the outer peripheral surface and the outer peripheral surface.
The cooling device according to claim 1 or 2, wherein a flow of cooling water in the heat exchange section is opposite to a fuel supply direction in the fuel supply pipe.
At least a part of the fuel supply pipe is arranged adjacent to at least one of the exhaust pipe or the exhaust manifold of the engine, and the heat exchange part is a part of the fuel supply pipe adjacent to the exhaust pipe or the exhaust manifold. The cooling device according to any one of claims 1 to 3, wherein the cooling device is provided.
The cooling device according to any one of claims 1 to 4, further comprising a second heat exchange portion that is formed in an annular shape surrounding the outer periphery of the nozzle portion of the exhaust pipe injector and in which cooling water flows.
The cooling device according to any one of claims 1 to 5, wherein the cooling water is supplied from a cooling water circulation circuit of the engine.