JP6413814B2 - Water-cooled cooler - Google Patents

Description

  The present invention is a water-cooled cooler that is arranged downstream of a supercharger and that flows supercharged intake air containing exhaust gas discharged from an internal combustion engine to the outer surface and cools the supercharged air intake with cooling water flowing inside About.

  As a technique for improving the fuel consumption of an internal combustion engine, an EGR (Exhaust Gas Recirculation) system in which exhaust gas generated by fuel combustion is recirculated to the intake side of the internal combustion engine and then re-intaked is becoming widespread.

  The exhaust gas generated by combustion in the internal combustion engine is in a state where oxygen is lean. When this exhaust gas and intake air are mixed, the oxygen concentration in the intake air becomes lower than that in the atmosphere. Therefore, in the internal combustion engine, combustion is performed in a state where the oxygen concentration is lower than that in the atmosphere, so that the combustion temperature is lowered. Thereby, generation | occurrence | production of the nitrogen oxide at the time of combustion, etc. can be suppressed, and it becomes possible to aim at the improvement of a fuel consumption.

  As one aspect of such an EGR system, one that supplies exhaust gas discharged from an internal combustion engine to a supercharger is known. In this aspect, in the supercharger, the supercharged intake air is compressed together with the exhaust gas and then supplied to the internal combustion engine.

  Supercharged intake air including exhaust gas is supplied to the internal combustion engine via an intercooler that is a cooler disposed on the downstream side of the supercharger. The supercharged intake air is cooled by passing through the intercooler, and the temperature is lowered to a high density state, thereby contributing to an improvement in output of the internal combustion engine.

  Various types of intercoolers can be adopted. For example, Patent Literature 1 below describes a stacked cooler configured by stacking a plurality of cooling pipes. Each cooling pipe has an inflow port for allowing fluid to flow into an internal flow path and an exhaust port for allowing fluid to flow out from the flow path. Each cooling pipe is laminated so that the mutual inlets communicate with each other and the mutual outlets communicate with each other. Even in the above-described intercooler, the supercharged intake air is allowed to flow on the outer surface of the cooling pipe, and the cooling water is allowed to flow inside the cooling pipe, so that it can be a laminated type as in the cooler described in Patent Document 1 below. Is possible.

British Patent Application No. 2449480

  However, as a result of the study by the present inventors, it has been found that if the supercharged intake air containing exhaust gas is cooled by the laminated intercooler, a new problem relating to corrosion of the cooling pipe is caused.

  The exhaust gas generated by combustion in the internal combustion engine contains moisture. For this reason, the condensed water generated by cooling the moisture adheres to the outer surface of the cooling pipe. Further, since the exhaust gas contains nitrogen oxides and sulfur oxides, the condensed water exhibits acidity when dissolved.

  In order to efficiently perform heat exchange between the cooling water inside the cooling pipe and the external supercharged intake air, it is preferable that the wall of the cooling pipe is formed with a thickness of less than 1 mm. However, when the tube wall is corroded by acidic condensate, the hole penetrating the cooling tube is formed by the formation of such a thin wall, which may cause leakage of the cooling water.

  As a countermeasure against such corrosion, it is known to provide a sacrificial layer on the outer surface of the cooling pipe. This sacrificial layer contains zinc and tends to corrode more easily than the base material constituting the cooling pipe. By providing the sacrificial layer uniformly on the outer surface of the cooling pipe, even when corrosion due to condensed water starts, the corrosion proceeds in the direction along the outer surface and thereby proceeds in the thickness direction of the pipe wall. This is to prevent the formation of holes.

  However, in a cooler in which adjacent cooling pipes are stacked by bringing them into contact with each other, there is a case where the concern that holes are formed instead increases due to the sacrificial layer provided as described above. That is, at the site where adjacent cooling pipes are in contact with each other, when the two cooling pipes are joined by brazing, the sacrificial layer of zinc may flow. When this zinc concentrates on the contact part of both cooling pipes, corrosion advances remarkably in a contact part, and a hole will be formed.

  The present invention has been made in view of such problems, and its purpose is to provide a cooler capable of suppressing required dimensional accuracy while suppressing corrosion that causes leakage of cooling water. It is to provide.

In order to solve the above problems, a water-cooled cooler according to the present invention is disposed downstream of a supercharger and causes supercharged intake air including exhaust gas discharged from an internal combustion engine to flow to the outer surface and to flow inside. A water-cooled cooler (10) that cools supercharged intake air with cooling water, wherein flow paths (41c, 42c) for flowing cooling water are formed therein, and an inlet (41a) for allowing cooling water to flow into the flow path , 42a) and outlets (41b, 42b) through which cooling water flows out from the flow path, and includes a plurality of stacked cooling pipes (40), and the cooling pipe includes a sacrificial layer containing zinc ( 40m1) on the outer surface (40s), and annular projections (52, 62) projecting outward are formed on the outer edges of the inlet and outlet, one adjacent cooling pipe and the other cooling pipe DOO is stacked across the collar (70) that have a plurality of through holes (71), one cold By inserting the annular protrusion of the pipe and the annular protrusion of the other cooling pipe into the collar through-hole in a non-contact state, the inlet of one cooling pipe and the inlet of the other cooling pipe communicate with each other. In addition, the outlet of one cooling pipe and the outlet of the other cooling pipe are configured to communicate with each other. In the flow path, the cooling water flows from the one end side toward the other end side along the direction intersecting the flow direction of the supercharged intake air, and then turns back at the other end side and flows toward the one end side. It is formed as follows. The plurality of inflow ports and outflow ports are arranged linearly along the flow direction of the supercharged intake air. The collar is formed in a flat shape so that its longitudinal direction extends over a plurality of inlets and outlets, and the through holes are formed at positions corresponding to the respective inlets and outlets.

  According to the present invention, the annular protrusion of one cooling pipe and the annular protrusion of the other cooling pipe are not in contact with each other due to the collar, so that the zinc of the sacrificial layer flows and concentrates on the contact portion. There is no. Therefore, it becomes possible to suppress the corrosion of the cooling pipe in which holes are formed.

  Further, according to the present invention, the annular protrusion of one cooling pipe and the annular protrusion of another cooling pipe are configured to communicate with each other by being inserted into the through hole of the collar. For this reason, the through hole of the collar may be formed larger than the annular protrusion. Therefore, even when a slight variation occurs in the dimension when forming the annular protrusion, the dimensional error can be absorbed in the through hole of the collar, so that the required dimensional accuracy can be suppressed. .

  ADVANTAGE OF THE INVENTION According to this invention, the cooler which can suppress the required dimensional accuracy can be provided, suppressing the corrosion which causes the leakage of a cooling water.

1 is a plan view showing a water-cooled intercooler according to an embodiment of the present invention. It is sectional drawing of the II-II cross section of FIG. It is an enlarged view of the III section of FIG. It is a disassembled perspective view of the heat exchange core part of the water-cooled intercooler of FIG. It is sectional drawing which shows the outer surface of a cooling pipe. It is sectional drawing which shows the outer surface of the cooling pipe which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, an outline of the configuration of a water-cooled intercooler 10 (hereinafter referred to as “intercooler 10”) according to an embodiment of the present invention will be described with reference to FIG. The intercooler 10 is a cooler that is arranged on the downstream side of a supercharger of a vehicle (not shown) and cools high-temperature supercharged intake air supplied from the supercharger. This vehicle employs an EGR system, and exhaust gas is supplied to the supercharger to return exhaust gas discharged from the engine to the intake port of the engine. Therefore, the supercharged intake air supplied from the supercharger to the intercooler 10 includes exhaust gas. Hereinafter, for convenience of explanation, this supercharged intake air including exhaust gas is also simply referred to as “supercharged air intake”.

  As shown in FIG. 1, the intercooler 10 includes a supercharged intake inflow portion 20, a heat exchange core portion 30, and a supercharged intake outflow portion 80.

  The supercharged intake inflow portion 20 is a duct in which a flow path for flowing supercharged intake air is formed. The supercharged intake inflow portion 20 receives the supercharged intake air that has passed through the supercharger described above from a supercharged intake inlet 21 that is an opening provided at one end. The flow path inside the supercharged intake air inlet 20 is configured to bend from the supercharged intake air inlet 21 to the outlet 22 at the other end, and the cross-sectional area of the flow path is enlarged. The supercharged intake air flows through this internal flow path, and is sent to the outside from the supercharged intake air outlet 22.

  The heat exchange core part 30 is a unit connected to the delivery port 22 of the supercharged intake air inflow part 20. As will be described later, the heat exchange core unit 30 causes the supercharged intake air that has passed through the supercharged intake air inflow portion 20 to flow into the interior, and exchanges heat with the cooling water flowing therethrough.

  The heat exchange core unit 30 includes an HT heat exchange core unit 31 and an LT heat exchange core unit 32. The HT heat exchange core part 31 is provided on the upstream side of the LT heat exchange core part 32, and the HT heat exchange core part 31 and the LT heat exchange core part 32 receive the supercharged intake air from the supercharged intake air inflow part 20. It is arranged in a straight line along the direction.

  The HT heat exchange core unit 31 is supplied with cooling water that circulates through the engine of the vehicle and cools the engine. When the cooling water flows into the HT heat exchange core portion 31 from an inflow pipe 31a provided at one end portion, the cooling water flows toward the other end portion in a direction intersecting with the flow direction of the supercharged intake air. Further, the cooling water is folded back at the other end portion of the HT heat exchange core portion 31 and flows toward the one end portion side, and is folded back and flows out from the HT heat exchange core portion 31 through the outflow pipe 31b.

  On the other hand, the LT heat exchange core part 32 is supplied with cooling water for cooling only the supercharged intake air flowing into the heat exchange core part 30. When the cooling water flows into the LT heat exchange core 32 from an inflow pipe 32a provided at one end, the cooling water flows toward the other end in a direction intersecting with the flow direction of the supercharged intake air. Further, the cooling water is folded back at the other end portion of the LT heat exchange core portion 32 and flows toward the one end portion side, and is folded back and flows out of the LT heat exchange core portion 32 through the outflow pipe 32b. The cooling water flowing into the LT heat exchange core part 32 is at a lower temperature than the cooling water flowing into the HT heat exchange core part 31.

  The supercharged intake / outflow part 80 is a duct in which a flow path for flowing supercharged intake is formed. The supercharged intake air outlet 80 receives the supercharged intake air that has passed through the heat exchange core 30. The supercharged intake air flows through the internal flow path that expands toward the downstream side, passes through the supercharged intake air outlet 80, and is then guided to the intake port of the engine.

  Next, the configuration of the heat exchange core unit 30 will be described with reference to FIGS. 2 to 4.

  As shown in FIG. 2, the heat exchange core unit 30 includes a plurality of cooling pipes 40 and a plurality of collars 70 inside a casing 33 that is a housing.

  The cooling pipe 40 is constituted by a pair of a first outer plate 50 and a second outer plate 60. Each of the first outer plate 50 and the second outer plate 60 is a member formed by processing a steel plate based on aluminum.

  As shown in FIG. 4, the first outer plate 50 has four cup portions 51 that protrude outwardly at one end thereof. The four cup parts 51 are linearly arranged along the flow direction of the supercharged intake air in the heat exchange core part 30. Each cup portion 51 is formed by burring, and has a step on its surface. Further, the first outer plate 50 has an annular protrusion 52 that protrudes further outward from each cup part 51.

  The second outer plate 60 is joined to the surface of the first outer plate 50 opposite to the surface on which the cup portion 51 is formed. As shown in FIG. 4, the second outer plate 60 has a cup portion 61 at one end thereof and at a position corresponding to each of the four cup portions 51. Each cup portion 61 is formed by burring, and has a step on its surface. Further, the second outer plate 60 has an annular protrusion 52 that protrudes further outward from each cup portion 61.

  As shown in FIG. 4, the cooling pipe 40 has an HT inlet 41a, an HT outlet 41b, an LT inlet 42a, and an LT outlet 42b at one end thereof. The HT inlet 41a, the HT outlet 41b, the LT inlet 42a, and the LT outlet 42b all pass through the cup portion 51 of the first outer plate 50 and the cup portion 61 of the second outer plate 60.

  The cooling pipe 40 has the HT flow path 41c which flows the cooling water which flowed in from the HT inflow port 41a, and guides it to the HT outflow port 41b while turning back at the other end. Further, the cooling pipe 40 has an LT flow path 42c through which the cooling water flowing in from the LT inflow port 42a flows and is led to the LT outflow port 42b while being folded at the other end.

  The collar 70 is a flat plate member made of aluminum. As shown in FIG. 4, the collar 70 is formed in a flat shape so that its longitudinal direction extends from the HT outlet 41b of the cooling pipe 40 to the LT inlet 42a. The collar 70 has four through holes 71 penetrating in the thickness direction at positions corresponding to the HT inlet 41a, the HT outlet 41b, the LT inlet 42a, and the LT outlet 42b.

  The heat exchange core part 30 is laminated so that the adjacent cooling pipes 40 and 40 sandwich the collar 70 therebetween. That is, the heat exchange core unit 30 is configured by alternately stacking the cooling pipes 40 and the collars 70. Hereinafter, the direction in which the cooling pipe 40 and the collar 70 are stacked is simply referred to as a “stacking direction”.

  As shown in FIG. 3, the cooling pipe 40 has its cup portions 51 and 61 in contact with both end faces in the thickness direction of the collar 70, and its annular protrusions 52 and 62 are inserted into the through holes 71 of the collar 70. To be placed. The cooling tube 40 and the collar 70 are fixed to each other by brazing using a brazing material containing silicon.

  The cooling pipe 40 is in a state in which the adjacent cooling pipes 40 are in communication with each other through the through holes 71, the HT inlet 41 a, the HT outlet 41 b, the LT inlet 42 a, and the LT outlet 42 b. Thereby, as shown in FIG. 2, tubular channels 34 a and 34 b extending in the stacking direction are formed inside the HT heat exchange core portion 31. In addition, tubular flow paths 35 a and 35 b that similarly extend in the stacking direction are formed inside the LT heat exchange core portion 32.

  Next, cooling of the supercharged intake air in the heat exchange core unit 30 configured as described above and countermeasures to the problems associated therewith will be described with reference to FIGS. 5 and 6 as well.

  The cooling water supplied to the HT heat exchange core part 31 via the inflow pipe 31a flows into the tubular flow path 34a from the HT inlet 41a of the cooling pipe 40 arranged closest to the inflow pipe 31a. The cooling water first flows through the tubular flow path 34a in the stacking direction and is distributed to the HT inlet 41a of each cooling pipe 40. The distributed cooling water flows into the HT channel 41c of each cooling pipe 40 and flows.

  High-temperature supercharged intake air supplied from the supercharged intake air inlet 20 flows between the cooling pipes 40 adjacent to each other in the stacking direction. Therefore, the cooling water flowing through the HT flow path 41c of the cooling pipe 40 exchanges heat with the supercharged intake air flowing through the outer surface 40s of the cooling pipe 40 via the pipe wall. As a result, the supercharged intake air is cooled by being deprived of heat by the cooling water, and its temperature is lowered. The supercharged intake air that has passed through the HT heat exchange core unit 31 is then supplied to the LT heat exchange core unit 32.

  The cooling water that has finished flowing through the HT flow path 41c is heated by the heat taken from the supercharged intake air, and the temperature is higher than when it flows into the HT flow path 41c. This cooling water flows out from the HT outlet 41b and then flows into the tubular channel 34b. When the cooling water flowing out from the HT outlet 41b of each cooling pipe 40 joins in the tubular flow path 34b, the cooling water flows in the stacking direction in the tubular flow path 34b. The cooling water flows into the outflow pipe 31b from the HT outflow port 41b of the cooling pipe 40 arranged closest to the outflow pipe 31b, and flows out from the HT heat exchange core portion 31 through the outflow pipe 31b.

  On the other hand, the cooling water supplied to the LT heat exchange core part 32 from the inflow pipe 32a flows into the tubular flow path 35a from the LT inlet 42a at one end. The cooling water flows in the stacking direction through the tubular flow channel 35 a and is distributed to the LT inlet 42 a of each cooling pipe 40. The distributed cooling water flows through the LT flow paths 42 c of the respective cooling pipes 40.

  The supercharged intake air that has passed through the HT heat exchange core 31 flows between the cooling pipes 40 adjacent to each other in the stacking direction in the LT heat exchange core 32. Therefore, the cooling water flowing through the LT flow path 42c of the cooling pipe 40 exchanges heat with the supercharged intake air flowing through the outer surface 40s of the cooling pipe 40 via the pipe wall. Thereby, the supercharged intake air is deprived of heat by the cooling water and cooled, and the temperature further decreases. The supercharged intake air that has passed through the LT heat exchange core portion 32 flows out of the LT heat exchange core portion 32 via the supercharged intake air outflow portion 80. As described above, the supercharged intake air is guided to the intake port of the engine after passing through the supercharged intake air outlet 80.

  The cooling water that has finished flowing through the LT flow path 42c is heated by the heat taken from the supercharged intake air, and the temperature is higher than when it flows into the LT flow path 42c. This cooling water flows out from the LT outlet 42b, and then flows into the tubular flow path 35b. When the cooling water flowing out from the LT outlet 42b of each cooling pipe 40 joins in the tubular flow path 35b, it flows in the stacking direction in the tubular flow path 35b. The cooling water flows into the outflow pipe 32b from the LT outflow port 42b of the cooling pipe 40 disposed closest to the outflow pipe 32b, and flows out of the LT heat exchange core portion 32 through the outflow pipe 32b.

  The cooling water that has flowed out through the outflow pipes 31b and 32b is supplied to a radiator mounted on the vehicle. In the radiator, the cooling water is cooled by heat exchange with air, and the temperature is lowered to the extent that it is again used for heat exchange in the engine and heat exchange core 30 of the vehicle.

  As described above, the supercharged intake air contains exhaust gas generated by combustion in the engine, and this exhaust gas contains moisture. For this reason, condensed water generated when the supercharged intake air is cooled adheres to the outer surface 40 s of the cooling pipe 40.

  Further, the exhaust gas contains nitrogen oxides and sulfur oxides. As these dissolve, the condensed water adhering to the outer surface 40s of the cooling pipe 40 becomes acidic. This acidic condensate causes corrosion of the cooling pipe 40 and may cause leakage of the cooling water.

  Therefore, in the intercooler 10 according to the present embodiment, a sacrificial layer 40m1 is provided on the outer surface 40s of the cooling pipe 40, as shown in FIG. The sacrificial layer 40m1 is clad on the surface of the base material 40b of the cooling pipe 40 made of aluminum, and the thickness thereof is about 30 to 40 μm. The sacrificial layer 40m1 is an alloy in which zinc is contained in aluminum, and has a characteristic that it is more easily corroded than the base material 40b.

  By providing such a sacrificial layer 40m1 uniformly on the outer surface 40s of the cooling pipe 40, even when corrosion due to condensed water starts, the corrosion proceeds in a direction along the outer surface 40s. That is, it is possible to prevent the corrosion due to the condensed water from proceeding in the thickness direction of the tube wall of the cooling pipe 40 and protect the base material 40b from corrosion. As a result, it is possible to prevent formation of a hole penetrating the tube wall of the cooling tube 40 and prevent leakage of cooling water.

  However, there are cases where there is an increased concern that a hole is formed instead of the sacrificial layer which is brought into contact with the two members having the sacrificial layer containing zinc on the outer surface and joined to each other by brazing.

  That is, at the contact portion, when the two members are joined by brazing, there is a risk that the zinc in the sacrificial layer flows together with silicon or the like contained in the brazing material. When this zinc concentrates on the contact part of both members, corrosion progresses remarkably in a contact part, and a hole will be formed.

  Therefore, in the heat exchange core part 30 of the intercooler 10 according to the present embodiment, the cooling pipes 40, 40 adjacent in the stacking direction are in a non-contact state. Specifically, as described above, the annular protrusions 52 and 62 of the cooling pipe 40 are inserted into the through hole 71 of the collar 70, but the annular protrusions 52 and 62 adjacent to each other inside the through hole 71 are arranged. The end portions are not contacted with a predetermined interval in the stacking direction. That is, the cooling pipe 40 is configured to be brazed to the collar 70 but not to the adjacent cooling pipe 40.

  As described above, according to the intercooler 10 according to the present invention, the collar 70 causes the annular protrusion 52 of the cooling pipe 40 and the annular protrusion 62 of the adjacent cooling pipe 40 to be in a non-contact state. The zinc in the sacrificial layer 40m1 does not flow and concentrate at the contact site. Therefore, it becomes possible to suppress corrosion of the cooling pipe 40 in which holes are formed.

  Further, the annular protrusion 52 of the cooling pipe 40 and the annular protrusion 62 of the adjacent cooling pipe 40 are configured to communicate with each other by being inserted into the through hole 71 of the collar 70. For this reason, the through hole 71 of the collar 70 may be formed larger than the annular protrusions 52 and 62. Therefore, even when some variation occurs in the dimensions when forming the annular protrusions 52 and 62, the dimensional error can be absorbed in the through hole 71 of the collar 70, so that the required dimensional accuracy can be obtained. Can be suppressed.

  Further, as in another embodiment of the present invention shown in FIG. 6, it is also preferable that the cooling pipe 40 has a brazing filler metal layer 40m2 containing silicon as a brazing filler metal on the outer surface. In this case, it is possible to achieve brazing with the collar 70 by melting the brazing material layer 40m2. Further, even when a corrugated fin or the like for increasing the heat transfer area is disposed between the adjacent cooling pipes 40, 40, the brazing can be easily performed.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Water-cooled intercooler (water-cooled cooler)
40: cooling pipe 40m1: sacrificial layer 40m2: brazing material layer 40s: outer surface 41a, 42a: inflow port 41b, 42b: outflow port 41c, 42c: flow channel 52, 62: annular protrusion 70: collar 71: through hole

Claims (2)

A water-cooled cooler (10) that is disposed downstream of the supercharger and that flows supercharged intake air containing exhaust gas discharged from the internal combustion engine to the outer surface and cools the supercharged air intake with cooling water flowing inside There,
A flow path (41c, 42c) for flowing cooling water is formed inside, an inlet (41a, 42a) for allowing cooling water to flow into the flow path, and an outlet (41b, 42b) for flowing cooling water from the flow path. And a plurality of cooling pipes (40) stacked,
The cooling pipe is
A sacrificial layer (40 ml) containing zinc on the outer surface (40 s);
An annular protrusion (52, 62) protruding outward is formed on the outer edge of the inlet and the outlet,
One cooling tube adjacent the other cooling tubes, are stacked to sandwich the collar (70) that have a plurality of through holes (71),
The annular protrusion of the one cooling pipe and the annular protrusion of the other cooling pipe are inserted into the through-hole of the collar in a non-contact state, so that the inlet of the one cooling pipe and the other The cooling pipe is configured to communicate with the inlet of the cooling pipe and to communicate with the outlet of the one cooling pipe and the outlet of the other cooling pipe .
The flow path is configured such that the cooling water flows from the one end side toward the other end side along the direction intersecting the flow direction of the supercharged intake air, and then is folded at the other end side to the one end side. It is formed to flow toward
The plurality of inlets and outlets are arranged linearly along the flow direction of the supercharged intake air,
The collar is formed in a flat shape so that its longitudinal direction extends over the plurality of inlets and outlets, and the through holes are formed at positions corresponding to the inlets and outlets. water-cooled condenser, characterized in that there.   The water cooling type cooler according to claim 1, wherein the cooling pipe has a brazing filler metal layer (40m2) on the outer surface.

Images