JPS6172831A - Cooling device of charging in internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve cooling efficiency of a device and prevent its constitutional parts from damage, by inserting both ends of a flat annular cooling water pipe into the hole of a pipe plate while the cooling water pipe and a fin, arranged between the cooling water pipes, into a cooler case and fixing the pipe plate to be formed in a thin thickness. CONSTITUTION:A cooler case 11 provides in its inside a plurality of cooling water pipes 15 to be extended parallelly to each other in a lateral direction, and a waveformed fin 16 is inserted respectively between the cooling water pipes 15. And both ends of each cooling water pipe 15 are respectively fixed to each pipe plate 17, 18, further each pipe plate 17, 18 is respectively fixed by a fixing tool 21, 22 integrally with the cooler case 11 together with each tank 19, 20 in an inlet and an outlet side. Here each pipe plate 17, 18 forms an oval hole 30, inserting both end parts of each cooling water pipe 15 into each hole 30. While each pipe plate 17, 18, being set to a uniform thickness about 1.5% as the length in the longitudinal direction of each cooling water pipe 15, flexibly forms the peripheral side from a position fixing each cooling water pipe 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a charge air cooling device for an internal combustion engine suitable for a multi-cylinder engine with a supercharger.

(Prior Art) For example, in a marine internal combustion engine, a supply air cooling device employing a round pipe as a cooling water pipe is conventionally used (for example, Japanese Patent Laid-Open No. 57-171027). However, with this configuration, the air cooled by the cooling water pipe stagnates near the cooling water pipe on the downstream side, resulting in poor cooling efficiency.

On the other hand, a configuration is already known that uses an annular pipe with a flat cross section to eliminate air stagnation and improve cooling efficiency.
For example, Utility Model Application No. 57-193925). In this case, since the cooling water pipe is flat, it is necessary to braze and fix the cooling water pipe and the tube sheet that supports it at both ends. However, when used in a marine internal combustion engine, for example, the cooling water passing through the cooling water pipe is approximately 20°C, while the supply air flowing outside is at a high temperature of approximately 100°C. Even though the cooling water pipes hardly expand, the cooler case that houses the cooling water pipes gets heat from the supply air and expands a lot. Therefore, when brazing between the wood pipe and the tube plate, a large amount of force is applied to the part, and brazing may cause damage to the part or the cooling water pipe.
This may cause cracks in the tube sheet. Especially when the cooler case is made of cast aluminum, the coefficient of thermal expansion is large.
This trend is remarkable.

(Problems to be Solved by the Invention) The above conventional configuration in which a round tube is used as a cooling water tube has a problem of poor cooling efficiency.

When the above-mentioned conventional structure using a pipe with a flat cross section is adopted for an air supply system for an internal combustion engine, there are problems such as damage to the parts and cooling water pipes, cracking of the tube sheet, etc. during brazing. ing.

The present invention uses cooling water pipes with a flat cross section that can improve cooling efficiency, and uses aluminum castings as the cooler case, thereby achieving a compact pumice air supply cooling system while at the same time It attempts to solve problems.

(Means for Solving the Problems) The present invention provides a plurality of cooling units having a flat annular cross section:
Both ends of the water tubes are inserted into the insertion holes of the tube plate and fixed, corrugated fins are placed between each cooling water tube, and the cooling water tubes and fins are inserted into a cooler case made of aluminum casting. This is a supply air cooling device for an internal combustion engine, characterized in that the tube plate is fixed and the thickness of the tube plate is set to be thin enough to absorb expansion and contraction due to heat of the cooler case by the deflection of the tube plate.

(Example) In Fig. 1, cooler case 1 made of aluminum casting
1 has a partition 12 in the center, and on both sides of the partition 12, an air supply inlet 13 and an air supply outlet 14 are opened toward -L. A plurality of cooling water pipes 15 extending in the left-right direction in the figure are inserted into the cooler case 11 so as to be parallel to each other, and there is a gap between each cooling water pipe 15 and between the cooling water pipe 15 and the inner wall surface of the cooler case 11. A corrugated fin 16 is inserted between each (partially omitted).Both ends of the cooling water pipe 15 are each fixed to a tube plate 17.18 (described in detail later).The tube plate 17.18 is From both left and right sides, tube plate 17.
The inlet tank 19 and the outlet tank 20, which are in pressure contact with the cooler case 18, are collinear with each other with nuts 21 and stud bolts 22, thereby being physically fixed to the cooler case 11. Naori - Ra case 11 and tank 19.
, 20 and the tube sheets 17 and 18, gaskets 23 are interposed between each tube plate 17 and 18 to maintain liquid tightness.

As shown in FIG. 2, for example, eight cooling water pipes 15 are provided, and the cross-sectional shape is an ellipse that is vertically elongated.

Four cooling water pipes 15 are arranged in two stages at equal intervals, and five fins 16 are arranged between each cooling water pipe 15 and between the cooling water pipe 15 and the inner wall surface of the cooler case 11. It is not bent in the 1F direction. Although not shown in the drawings, the fins 16 are preferably provided with louvers. Further, the portion of the fin 16 that contacts the cooling water pipe 15 is fixed to the cooling water pipe 15 by brazing.
This keeps it in place. The lower end of the fin 16 is placed in the vertical middle of the space formed in the cooler case 11, and a lower chamber 24 is provided by forming a space free of obstacles in the lower part of the cooler case 11. It is being

As shown in FIG. 3, both ends of the cooling water tR15 are connected to the tube plate 17.
(18) is fixed. Oval holes 30 corresponding to the outer diameters of the cooling water pipes 15 are formed in the tube plate 17 (18) at positions corresponding to the respective cooling water pipes 15. After both ends of the cooling water pipe 15 are inserted into the eight holes 30, they are fixed by brazing while maintaining airtightness. Four holes 31 through which the stud bolts 22 (Fig. 1) are inserted are formed on the outer circumference of the tube plate 17 (18), and are located at the back of the outer circumference of the tube plate 17 (1B), closer to the imaginary line. The outer circumferential portion corresponds to the portion held between the outer circumferential portions of the cooler case 11 and the tank 19, 20 (FIG. 1).

The tube plate 17 (18) has a uniform thickness of about 1.5% with respect to the length of the cooling water pipe 15 in the longitudinal direction, and can be relatively easily attached to the outer peripheral side than the fixed position of the cooling water pipe 15. It is designed to be flexible. Considering the degree of deflection, the thickness of the tube plate 17 (18) is normally limited to about 3.0% of the length of the cooling water pipe 15 in the longitudinal direction. Also, tube plate 17 (
When considering the corrosion resistance -〇- and strength of 18), it is preferable to have a roughness of 0.8 mmmm.

The charge air cooling device shown in FIGS. 1 to 3 is installed, for example, in an internal combustion engine as shown in FIG. 4. In FIG. 4 (arrow F points forward), an engine body 40 consisting of a cylinder block, cylinder head, etc. has a flywheel housing 41 at its rear end, for example.
A supercharger 42 is disposed approximately above and behind the engine body 40, and an alternator 4 is disposed near the top on the opposite side (front side).
3 is arranged and "C" is installed.Supercharger 42 and alternator 43
In between, an exhaust manifold 45 and a charge air cooling device 46 (intercooler) according to the present invention are provided on the upper side of the engine body 40 in a form extending parallel to a crankshaft 47 (only the center line is shown). Exhaust manifold 45
A fresh water cooler 50 is provided along the inside of the upper end.

The intake near duct 51 attached to the charge air cooling device 46 extends generally above the supercharger 42 and behind the fresh water cooler 50, and has an outlet connected to the charge air inlet D13 of the charge air cooling device 46 (FIG. 1).
is connected to. Further, a discharge air duct 52 attached to the supply air cooling device 46 extends along the front and upper surface of the intake air duct 51, and its inlet is connected to the supply air n of the supply air cooling device 46.
14 (Fig. 1).

A mixing elbow 55 is attached to the supercharger 42. The mixing elbow 55 is located behind the exhaust manifold 45 and the supply air cooling device 46, and a seawater pipe 56 is provided between the mixing elbow 55 and the fresh water cooler 50. The seawater pipe 56 connects the rear end of the fresh water cooler 50 and the front end of the mixing elbow 55, and supplies seawater from the fresh water cooler 50 to the mixing elbow 55 via the seawater pipe 56. A seawater pipe 57 that supplies seawater to the fresh water cooler 50 is provided near the seawater pipe 56. The exhaust pipe 158 of the mixing elbow 55 opens rearward and diagonally downward, and is connected to an exhaust pipe (not shown).

Next, the operation will be explained. In FIG. 4, engine exhaust gas enters the turbine of the supercharger 42 through the trachea 54,
After driving the supercharger 1142, it is discharged from the mixing elbow 55 to an exhaust pipe (not shown). Further, the seawater supplied from the seawater pipe 57 to the fresh water cooler 50 cools the fresh water (cooling water) in the fresh water cooler 50, and then is sent to the mixing elbow 55 via the seawater pipe 56. This seawater is mixed with the exhaust gas in the mixing elbow 55 to reduce the thermal energy and noise energy of the exhaust gas, and is discharged together with the exhaust gas to the exhaust pipe.

On the other hand, after the intake air is pressurized by supercharging vs42,
It flows from the suction 1 adduct 51 to the charge air cooling device 46 .

The cooling water passes through the cooling water pipe 15 shown in FIGS. 1 and 2 from the inlet side tank 19 to the outlet side tank 20. The supply air is introduced into the cooler case 11 from the supply air inlet 13 , passes through the gap between the fins 16 from above to the lower chamber 24 , reverses itself in the lower chamber 24 , passes through the gap between the fins 16 again, and enters the supply air outlet 14 From there, it is spun out to the UL outlet air duct 52. During this time, the supply air is cooled by removing heat from the cooling water passing through the cooling water pipe 15, and is supplied to the combustion chamber from the exhaust pipe 7 duct 52 via an air supply manifold (not shown).

Here, the temperature of the cooling water normally flowing inside the cooling water pipe 15 is approximately 2
0°C, whereas the supply air is heated adiabatically and compressively to about 100°C. Therefore, while the cooling water pipe 15 through which the cooling water passes has almost no thermal expansion, the cooler case 11 is heated by the supplied air and undergoes a large thermal expansion. However, in this case, the tube plates 17 and 18 that connect the cooling water pipes 15 and the cooler case 11 are set to be sufficiently thin and can be easily bent.
Mainly, the portion closer to the inner circumference than the virtual line in FIG. 3 is bent to absorb the distortion caused by the thermal expansion. Although there is a difference in thermal expansion between the bundled cooler case 11 and the cooling water pipe 15, brazing between the cooling water pipe 15 and the tube plate 17.18 may cause damage to the parts or the cooling water pipe 15 itself. No cracks or the like will occur.

(Effects of the Invention) Both ends of the plurality of cooling water pipes 15 having a flat annular cross section are inserted and fixed into the insertion holes 30 of the tube plate 17 and 18, and corrugated fins 16 are arranged between each cooling water pipe 15. At the same time, the cooling water pipes 15 and fins 16 are inserted into the cooler case 11 made of aluminum casting, the tube plates 17 and 18 are fixed, and the thickness of the tubes and 17 and 18 is adjusted by expanding and contracting due to the heat of the cooler case 11. (a) Even if the cooler case 11 thermally expands, the tube plate 17.1
Since the distortion is absorbed by the cooling water pipe 15 and the tube plate 17, 18, damage to the cooling water pipe 15 itself and cracking of the tube plate 17, 18 can be prevented during brazing between the cooling water pipe 15 and the tube plate 17, 18. Therefore, the durability of the supply air cooling device can be greatly improved.

(b) Even if aluminum casting with a large coefficient of thermal expansion is used as the cooler case 11, no damage will occur due to thermal expansion. Therefore, by forming the cooler case 11 by casting aluminum laminate, it is possible to reduce the weight of the air supply cooling device without sacrificing durability.

(C) Brazing between cooling water pipe 15 and tube plate 17.18 1
1. Since damage to a portion of the cooling water pipe 15 can be prevented, a pipe having a flat cross-section and a tubular shape with excellent heat exchange efficiency can not be used as the cooling water pipe 15. Cooling water pipe 15 having a flat annular cross section
The combination of the fins 16 and the fins 16 significantly improves the cooling efficiency (for example, about twice) compared to the conventional configuration in which a round tube and fins are combined.

As a result, it is also possible to downsize the supply air cooling device itself. Therefore, even if it is installed on the outside of the exhaust manifold, the overhang can be reduced.
By installing the charge air cooling device, the space outside the exhaust manifold can be used effectively, and the internal combustion engine itself can be made more compact.

(Another Embodiment) (a) In the above embodiment, the present invention is applied to a two-pass type supply air cooling system, but the present invention can also be applied to, for example, a one-pass or three-pass type supply air cooling system. Inventions can be adopted.

(b) The tube plate 17 (18) may also have the configuration shown in FIG. In FIG. 5, only the outer peripheral part of the tube plate 17 (18) is set to be thin as in the embodiment shown in FIG. The base is thick so that the strength of the part can be easily ensured. In this case as well, distortion due to thermal expansion can be absorbed by bending the thin peripheral portion, and a similar effect can be obtained.

(C) The tube plate 17 (18) may also have the configuration shown in FIG. In FIG. 6, the boss portion is formed by burring the hole 30, and the tube plate 17 (18
) is thin, the cooling water pipe 15 and tube plate 17 (1
8) Brazing between the parts can easily ensure the strength of the parts.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a supply air cooling device according to the present invention, FIG.
Figure 3 is a ■-■ cross-sectional view and ■-■ cross-sectional partial view of Figure 1,
FIG. 4 is a schematic side view of an internal combustion engine employing the charge air cooling device according to the present invention, and FIGS. 5 and 6 are longitudinal sectional views of different embodiments. 11... Cooler case, 15... Cooling water pipe, 16
...-13~ Fin, 17.18...Tube sheet, 30...Through hole Patent applicant Yanmar Diesel Co., Ltd. (1 other person) School LD. law

Claims (2)

[Claims] (1) Both ends of a plurality of cooling water pipes having a flat annular cross section are inserted into the insertion holes of the tube plate and fixed therein, and corrugated fins are arranged between each cooling water pipe, and the cooling water pipes and fins are connected to each other. The tube plate is fixed by being inserted into a cooler case made of aluminum casting, and the thickness of the tube plate is set to be thin enough to absorb the expansion and contraction caused by the heat of the cooler case by the deflection of the tube plate. Charge air cooling system for internal combustion engines. (2) The charge air cooling device for an internal combustion engine according to claim 1, wherein the thickness of the tube plate is set to 3% or less of the length of the cooling water pipe.