JP2001280130A - Cooling structure for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and lightweight cooling structure of a simple structure capable of reducing the manufacturing cost and the maintenance cost, for an engine comprising an oil cooler and an EGR cooler. SOLUTION: A heat exchanging core of the oil cooler is mounted at an upstream side of a cooling water path in a casing provided with a cooling water inlet for taking the engine cooling water as a cooling medium from a cooling water system of the engine, and a cooling water outlet for discharging the cooling water and returning the same to the engine, and a heat exchanging core of the EGR cooler is mounted at its downstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling structure suitable for an engine, particularly an engine for a vehicle such as a truck.

[0002]

BACKGROUND OF THE INVENTION engine for conventional truck or the like vehicle, in order to reduce the NO _x is detrimental components in the exhaust gas, and recirculating part of exhaust gases to the intake system so as to supply to the combustion chamber of an engine EGR (exhaust gas recirculation) has been widely implemented. In addition, in the above EGR, when exhaust gas having a significantly higher temperature than that of the intake air is added to the intake air and recirculated, the intake charge efficiency is reduced and the performance such as the output of the engine is deteriorated. E that cools the recirculated exhaust gas before supplying it to the intake system
GR coolers have been adopted.

On the other hand, in high-load engines such as diesel engines for trucks, the lubricating oil used to lubricate the sliding parts such as the pistons and crankshafts of the engine and becomes high in temperature and deteriorates quickly, so that the lubricating performance and durability are high. In order to secure the oil pressure, an oil cooler that cools oil using cooling water of the engine as a refrigerant is usually provided.

A conceptual configuration of a vehicle diesel engine provided with the oil cooler and the EGR cooler will be described with reference to FIG. In the figure, reference numeral 10 generally indicates an engine,
The engine 10 includes an engine body 12 having a crankcase or a cylinder block and a cylinder head, an intake passage 16 including an intake manifold 14, and an exhaust passage 20 including an exhaust manifold 18. Oil that has been heated to a high temperature after flowing through various parts of the engine that require lubrication and cooling, such as the piston and crankshaft of the engine body 12, is cooled by the oil cooler 22, and the main oil gallery 24 in the engine body 12 (only a part thereof is shown in the figure). Are indicated by dotted lines). The intake passage 16
And the exhaust passage 20 are connected by an EGR passage 26,
The EGR passage 26 has an EGR cooler 28 and an EGR valve 3
0 is interposed.

The oil cooler 22 is a multi-tube type heat exchange core having a plurality of small-diameter pipes through which oil flows, or a multi-plate type heat exchange core in which oil and cooling water passages are alternately arranged between a number of juxtaposed plates. A cooling water inlet for guiding cooling water in the engine body to the heat exchange core; and a cooling water outlet for returning cooling water flowing through the heat exchange core to the engine body. Although the oil cooler 32 is shown as an independent member outside the engine body 12 in the illustrated case, the oil cooler 32 may be housed in the crankcase of the engine body 12. Reference numeral 38 denotes an oil inlet for supplying oil accumulated in the oil pan of the engine body 12 to the heat exchange core 32 via an oil pump (not shown), and reference numeral 40 designates oil flowing through the heat exchange core 32. An oil outlet for supplying to the main oil gallery 24. The EGR cooler 28 is
The multi-tubular or multi-plate heat exchange core 42, a cooling water inlet 44 for guiding the cooling water in the engine body 12 to the heat exchange core 42, and the cooling water flowing through the heat exchange core 42 to the engine body 12. And a return cooling water outlet 46. The EGR valve 30 is a variable opening valve device that controls the EGR gas flow according to the operating state of the engine 10.

In the above-mentioned conventional engine, the oil cooler 22 and the EGR cooler 28 require cooling water inlets 34, 44 and cooling water outlets 36, 46 for supplying and discharging engine cooling water as a refrigerant to the oil cooler 22 and the EGR cooler 28, respectively. In addition, there is a problem that the structure including the pipe joints and related members such as packing for maintaining watertightness is complicated, the production and maintenance costs are increased, and the weight is increased.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages and drawbacks in the cooling structure of an engine provided with the oil cooler and the EGR cooler, and has a simple structure, light weight, and reduced production and maintenance costs. It is a primary object to provide a cooling structure.

[0008]

In order to achieve the above object, the present invention provides a cooling water passage having a cooling water inlet into which cooling water for an engine flows and a cooling water outlet from which the cooling water flows out; An oil cooler that is disposed upstream in the cooling water passage and cools the engine oil by using the cooling water as a coolant; and a cooling that is disposed downstream of the oil cooler and passes through the oil cooler in the cooling water passage. An engine cooling structure including an EGR cooler that cools engine exhaust gas using water as a refrigerant is proposed. In the present invention, the oil cooler and the EG
Preferably, the R cooler is housed in a casing forming a cooling water passage having a cooling water inlet at one end and a cooling water outlet at the other end.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIG. Note that the same reference numerals are used for members and portions that are substantially the same as the cooling structure in the conventional engine already described with reference to FIG.

As shown, heat exchange of the oil cooler 22 is upstream in a cooling water passage 54 inside a single casing 52 having a cooling water inlet 48 at one end and a cooling water outlet 50 at the other end. The core 32 is stored, and the heat exchange core 42 of the EGR cooler 28 is stored on the downstream side. The cooling water inlet 48 opens at or near the outlet of a water pump 56 provided in the engine main body 12 and driven in conjunction with the crankshaft, and the cooling water outlet 50 is connected to a cooling water chamber in the engine main body 12. It is preferred to open to a relatively low pressure downstream section.

As the heat exchange cores 32 and 42 of the oil cooler 22 and the EGR cooler 28, a multi-tube or multi-plate heat exchanger can be arbitrarily adopted as in the conventional engine cooling structure. In the case of a normal truck engine, the temperature of the oil supplied to the heat exchange core 32 of the oil cooler 22 is about 150 ° C. during continuous high-load operation, while the cooling oil supplied to the heat exchange core 32 as a refrigerant. Since the temperature of the water is 100 ° C. or less, sufficient heat exchange is performed between the cooling water and the oil, and the oil is effectively cooled. Further, the temperature of the exhaust gas supplied to the heat exchange core 42 of the EGR cooler 28 disposed downstream of the oil cooler 22 is usually 5 in an engine operation region where EGR is performed.
The temperature of the cooling water passing through the oil cooler 22 does not become higher than the temperature of the oil and is lower than 150 ° C., so that the temperature difference between the exhaust gas and the cooling water is sufficiently large. Therefore, the exhaust gas is cooled to a sufficiently low temperature and supplied into the intake passage 16, and as a result, the intake charge rate of the engine is improved, and the performance such as the engine output is improved.

According to the above configuration, the single casing 52
In the cooling water passage 54, the heat exchange core 32 of the oil cooler 22 is disposed upstream, and the heat exchange core 42 of the EGR cooler 28 is disposed downstream thereof. Since the cooling water inlet 48 and the cooling water outlet hole 50 are provided, there is an advantage that the structure is simple, small and lightweight as a whole, and the manufacturing and maintenance costs can be reduced as compared with the conventional engine cooling structure. The cooling water passage 54 can be formed inside the crankcase of the engine body 12, and in this case, the casing 52 can be formed by a partition wall provided in the cooling water chamber of the crankcase and a side wall of the crankcase. it can.

[0013]

As described above, the cooling structure for an engine according to the present invention comprises a cooling water passage having a cooling water inlet through which cooling water flows into the engine and a cooling water outlet through which the cooling water flows out; An oil cooler that is disposed upstream in the cooling water passage and cools the oil of the engine using the cooling water as a coolant; and an oil cooler that is disposed downstream of the oil cooler in the cooling water passage and passes through the oil cooler. An EGR cooler that cools engine exhaust gas using cooling water as a coolant is provided, and has the advantage of being able to provide this kind of cooling structure that is simple, compact, lightweight, and has low manufacturing and maintenance costs. . Further, in the present invention, the oil cooler and the EGR cooler are housed in a casing forming a cooling water passage having a cooling water inlet at one end and a cooling water outlet at the other end. Is stored in the casing that limits the cooling water passage, so that there is an advantage that the degree of freedom in arrangement with respect to the engine body is large and the arrangement in a narrow engine room is easy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a preferred embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a cooling structure in a conventional engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Engine, 12 ... Engine main body, 16 ... Intake passage, 20 ... Exhaust passage, 22 ... Oil cooler, 24 ... Main oil gallery, 26 ... EGR passage, 28 ... EGR cooler, 30 ... EGR valve, 48 ... Cooling water inlet 50 cooling water outlet, 52 casing, 54 cooling water passage, 5
6 Water pump.

Claims (2)

[Claims] 1. A cooling water passage having a cooling water inlet into which cooling water of an engine flows, and a cooling water outlet through which the cooling water flows out, and a cooling water passage disposed upstream of the cooling water passage and cooling the cooling water. An oil cooler that cools oil of the engine, and an EGR cooler that is disposed in the cooling water passage downstream of the oil cooler and cools engine exhaust gas by using cooling water that has passed through the oil cooler as a refrigerant. An engine cooling structure, characterized in that: 2. The oil cooler and the EGR cooler,
The cooling structure for an engine according to claim 1, wherein the cooling structure is housed in a casing forming a cooling water passage having a cooling water inlet at one end and a cooling water outlet at the other end.