JP2021001589A - Water cooled engine - Google Patents

Abstract

To provide a water cooled engine that can reduce horsepower loss when the engine rotates at low speed, and can obtain high output when it rotates at low speed with high load.SOLUTION: A water cooled engine comprises a water pump, and a cooling water jacket around a combustion chamber, and is constituted so that engine cooling water 4 is circulated between the water pump and the cooling water jacket. The water pump comprises a pump housing, a rotating shaft 6 inserted into the pump housing, and an impeller 7 attached to the rotating shaft 6 in the pump housing. When the engine rotates at low speed, the blade 9 takes a falling attitude 12 due to unbalance force 16 based on biasing force 11a of biasing means 11 and centrifugal force 9a acting on a blade 9. When the engine rotates at high speed, the blade 9 in the falling attitude 12 gets closer to a rising attitude 13 along a direction parallel to the rotating shaft 6 due to the unbalance force 16.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water-cooled engine, and more particularly to a water-cooled engine capable of reducing horsepower loss at low engine speeds and obtaining high output at low speeds and high load.

Conventionally, a water pump and a cooling water jacket around the combustion chamber are provided, and the engine cooling water is configured to circulate between the water pump and the cooling water jacket. The water pump is inserted into the pump housing and the pump housing. There is a water-cooled engine having a rotating shaft and an impeller attached to the rotating shaft in the pump housing (see, for example, Patent Document 1).

Jikkai Sho 62-40219 (see Figures 1 to 3)

<< Problem 1 >> There is a risk that horsepower loss will increase when the engine speed is low.
In the engine of Patent Document 1, the blades of the impeller are fixed to the base plate in an upright posture parallel to the rotation axis. In this engine, when the engine speed is low, a large pumping resistance of engine cooling water is applied to the blades in the standing posture, which may increase horsepower loss.

<< Problem 2 >> High output may not be obtained at low rotation and high load.
In the engine of Patent Document 1, the heat radiation from the combustion chamber becomes excessive due to the large amount of cooling water pumped to the cooling water jacket at the time of low rotation and high load in which the heat radiation time from the combustion chamber becomes long due to the slow ascent and descent of the piston. Due to unstable combustion, high output may not be obtained.

An object of the present invention is to provide a water-cooled engine capable of reducing horsepower loss at low engine speeds and obtaining high output at low speeds and high load.

The main configurations of the present invention are as follows.
As illustrated in FIG. 2, a water pump (1) and a cooling water jacket (3) around a combustion chamber (2) are provided, and engine cooling water is provided between the water pump (1) and the cooling water jacket (3). (4) is configured to circulate,
The water pump (1) includes a pump housing (5), a rotating shaft (6) inserted in the pump housing (5), and an impeller (7) attached to the rotating shaft (6) in the pump housing (5). )
As illustrated in FIG. 1 (B), when the engine speed is low, the unbalanced force (16) based on the urging force (11a) of the urging means (11) and the centrifugal force (9a) applied to the blades (9). The wings (9) are in the prone position (12).
At high engine speed, the disproportionate force (16) causes the blades (9) in the lying position (12) to approach the standing position (13) along the direction parallel to the rotation axis (6). A water-cooled engine that features that.

The invention of the present application has the following effects.
<< Effect 1 >> Horsepower loss at low engine speed can be reduced.
In this engine, when the engine speed is low, the blades (9) illustrated in FIG. 1 (B) are in the inverted posture (12), so that the pumping resistance of the engine cooling water (4) applied to the blades (9) is reduced. Horsepower loss can be reduced.

<< Effect 2 >> High output can be obtained at low rotation and high load.
In this engine, at low rotation and high load, the blades (9) illustrated in FIG. 1 (B) are in the inverted posture (12), and the engine cooling water (4) to the cooling water jacket (3) illustrated in FIG. Since the pumping amount of the engine is reduced, the heat radiation time from the combustion chamber (2) becomes longer due to the slow movement of the piston (14). Even at low rotation and high load, the heat radiation amount from the combustion chamber (2) is reduced and stable. High output can be obtained by combustion.

<< Effect 3 >> Appropriate cooling performance can be obtained when the engine speed is high.
In this engine, the blades (9) in the lying posture (12) illustrated in FIG. 1 (B) approach the standing posture (13) at high engine speeds where the calorific value increases, and the cooling water jacket (exemplified in FIG. 2) is used. The amount of pumped engine cooling water (4) to 3) is increased, and appropriate engine cooling performance can be obtained.

It is a figure explaining the impeller used for the water-cooled engine which concerns on embodiment of this invention, FIG. 1A is a front view, and FIG. 1B is a cross section taken along line BB of FIG. 1A. It is a vertical sectional view of the side surface of the main part of the water-cooled engine which concerns on embodiment of this invention. It is a vertical sectional view of the side surface of the water-cooled engine of FIG. 4A is a front view of the front housing, FIG. 4B is a sectional view taken along line BB of FIG. 4A, and FIG. 4A is a view for explaining a pump housing and an impeller used in the water-cooled engine of FIG. (C) is an explanatory view of a low friction film on the surface of the impeller.

1 to 4 are views for explaining a water-cooled engine according to an embodiment of the present invention, and in this embodiment, a water-cooled vertical in-line multi-cylinder diesel engine will be described.

As shown in FIG. 3, this engine includes a cylinder block (17), a cylinder head (18) assembled on the upper part of the cylinder block (17), and a cylinder head cover (18) assembled on the upper part of the cylinder head (18). 19), the crankshaft (10) erected in the crankcase (20) of the cylinder block (17), and the crankshaft (10) erected in the front-rear direction, with one of them in front of the cylinder block (17). ), The engine cooling fan (21) assembled to the front of the water pump (1), and the radiator (22) arranged in front of the engine cooling fan (21). ), A fly wheel (23) arranged at the rear of the cylinder block (17), and an oil pan (24) assembled at the bottom of the cylinder block (17).

This engine is equipped with a water cooling system.
As shown in FIG. 3, the water cooling device includes a water pump (1), a cooling water jacket (3) to which the engine cooling water (4) of the water pump (1) is pumped, and an engine of the cooling water jacket (3). It includes a thermostat accommodating pipe (25) for leading out the cooling water (4), a thermostat (26) accommodating in the thermostat accommodating pipe (25), and a radiator (22). When the water temperature of the engine cooling water (4) of the cooling water jacket (3) is low, the thermostat (26) returns the engine cooling water (4) of the cooling water jacket (3) to the water pump (1) to change the water temperature. When is high, the engine cooling water (4) of the cooling water jacket (3) is led out to the radiator (22).

As shown in FIG. 2, the cooling water jacket (3) includes a cylinder jacket (3a) provided in the cylinder block (17) and a head jacket (3b) provided in the cylinder head (18). The engine cooling water (4) pumped from the water pump (1) flows from the cylinder jacket (3a) to the thermostat accommodating pipe (25) via the head jacket (3b).

As shown in FIG. 2, this engine includes a water pump (1) and a cooling water jacket (3) around the combustion chamber (2), between the water pump (1) and the cooling water jacket (3). The engine cooling water (4) is configured to circulate.
The water pump (1) includes a pump housing (5), a rotating shaft (6) inserted in the pump housing (5), and an impeller (7) attached to the rotating shaft (6) in the pump housing (5). ) Is provided.
The impeller (7) includes a base plate (8) mounted in a posture orthogonal to the rotation axis (6) and blades (9) provided on the base plate (8), and the impeller (7) is a crank shown in FIG. It is driven by the shaft (10), and as shown in FIG. 2, the engine cooling water (4) is configured to be pumped by the blades (9) in the centrifugal direction of the impeller (7).

As shown in FIG. 1 (B), the blades (9) are attached to the base plate (8) in an undulating manner, and are urged in a prone position by the urging force (11a) of the urging means (11).
As shown in FIG. 1 (B), when the engine speed is low, the blades have an unbalanced force (16) based on the urging force (11a) of the urging means (11) and the centrifugal force (9a) applied to the blades (9). (9) is placed in the prone position (12). This unbalanced force (16) generates an unbalanced moment based on the urging force (11a) of the urging means (11) and the centrifugal force (9a) applied to the blade (9), and causes the blade (9) to lie down (9). 12).
When the engine is rotating at high speed, the disproportionate force (16) causes the blades (9) in the lying posture (12) to approach the standing posture (13) along the direction parallel to the rotation axis (6).

In this engine, when the engine speed is low, the blades (9) shown in FIG. 1 (B) are in the inverted posture (12), so that the pumping resistance of the engine cooling water (4) applied to the blades (9) is reduced and the horsepower is reduced. You can reduce the loss.

Further, in this engine, at the time of low rotation and high load, the blades (9) shown in FIG. 1 (B) are in the inverted posture (12), and the engine cooling water (4) to the cooling water jacket (3) shown in FIG. Since the pumping amount of the engine is reduced, the heat radiation time from the combustion chamber (2) becomes longer due to the slow movement of the piston (14). Even at low rotation and high load, the heat radiation amount from the combustion chamber (2) is reduced and stable. High output can be obtained by combustion.

Further, in this engine, the blades (9) of the lying posture (12) shown in FIG. 1 (B) approach the standing posture (13) at the time of high rotation of the engine where the calorific value increases, and the cooling water jacket (cooling water jacket) shown in FIG. The amount of pumped engine cooling water (4) to 3) is increased, and appropriate engine cooling performance can be obtained.

As shown in FIG. 1 (B), the blade (9) is provided with a locked portion (15), and the locked portion (15) is locked to the base plate (8) when the engine speed exceeds a predetermined number of revolutions. The blades (9) are configured to maintain an upright posture (13).

In this engine, when the engine speed exceeds a predetermined number of revolutions, the locked portion (15) is locked to the base plate (8) shown in FIG. 1 (B), so that the blades (9) do not sway and the engine is cooled. The pulsation of the water (4) is unlikely to occur, and the pump efficiency of the water pump (1) shown in FIG. 2 at high engine speed can be increased.

As shown in FIG. 2, the pump housing (5) includes a front housing (5a) and a rear housing (5b) that covers the front housing (5a) from the rear side, and the front housing (5a) is a bearing boss (5a). 5c), the cooling water introduction pipe (5d) that introduces the engine cooling water (4) from the radiator (22), and the engine cooling water (4) of the thermostat accommodating pipe (25) bypass the radiator (22). The pump (1) is provided with a cooling water bypass pipe (5e) that bypasses, and the rear housing (5b) is provided with a cooling water jacket (3) provided with a cooling water outlet passage (5f) for guiding the engine cooling water (4). There is.

The bearing (27) is housed in the bearing boss (5c) of the front housing (5a), and the rotating shaft (6) supported by the bearing (27) is inserted into the pump housing (5) to form the rotating shaft (6). An input pulley (28) and an engine cooling fan (21) are attached to the front end, an impeller (7) is attached to the rear end of the rotating shaft (6) in the rear housing (5b), and the rotating shaft (6) is It is watertightly sealed with a mechanical seal (29) in the front housing (5a).

As shown in FIG. 1 (A), the impeller (7) includes a base plate (8), six blades (9), and an urging means (11).
The base plate (8) has a plate boss (8b) raised in a direction perpendicular to the center of the flat plate body (8a) shown in FIGS. 1 (A) and 1 (B), and a plate body (8a) shown in FIG. 1 (B). It is provided with an upright piece (8c) standing upright from the peripheral edge of the above, a pivot support boss (8d) fixed to the upright piece (8c), and a pivot (8e) internally supported by the pivot support boss (8d). ing.

The blade (9) includes a loose fitting boss (9b) attached to the base end and a locked portion (15) attached to the loose fitting boss (9b), and the loose fitting boss (9b) is a base plate (8). ) Is loosely fitted to the pivot (8e), and is undulatingly attached to the base plate (8) with the tip end as a swingable free end, and the locked portion (15) is attached to the upright piece (8c) of the base plate (8). By being locked, the standing posture (13) of the blade (9) is maintained.
The urging means (11) is a pull spring, which is erected between the plate body (8a) and the blade (9).

As shown in FIG. 1 (A), the impeller (7) rotates clockwise as shown by the arrow (7a) when viewed from the front side, and the engine cooling water (4) shown in FIG. 2 is applied to the impeller (7). Pump in the centrifugal direction. As shown in FIG. 3, the impeller (7) is driven from the crankshaft (10) via the fan belt (30).

A water-repellent coating is formed on the surfaces of the base plate (8) and the blades (9) constituting the impeller (7) shown in FIGS. 1A and 1B.
Therefore, the water-repellent film reduces the flow resistance of the engine cooling water (4) to the impeller (7) and increases the pump efficiency.
Further, the impeller (7) having reduced water flow resistance has reduced vibration and pump noise.
A fluororesin film can be used as the water-repellent film.

The surface of the impeller (7) may be a low friction surface.
In this case as well, the frictional resistance of the engine cooling water (4) with respect to the impeller (7) is reduced on the low friction surface as in the case of the water repellent film, and the pump efficiency is increased.
Further, the impeller (7) in which the frictional resistance of the engine cooling water (4) is reduced has reduced vibration and pump noise.

Specific examples of the low friction surface include a glass coat, a metal mirror-finished surface, and a low friction film (33) shown in FIG. 4C.
The low friction film (33) will be described later.

As shown in FIGS. 4A and 4B, the front housing (5a) constituting the pump housing (5) of the water pump (1) has a surface of the front housing (5a) and a peripheral surface of the bearing boss (5c). It is provided with a heat radiation fin (5 g) that rises along the corner portion (5 h) of the.
Therefore, the cooling efficiency of the engine cooling water (4) and the bearing (27) shown in FIG. 2 can be improved by the heat radiated by the heat radiating fins (5 g).

A plurality of heat radiation fins (5 g) shown in FIG. 4 (B) are formed radially from the peripheral surface of the bearing boss (5c) along the surface of the front housing (5a) as shown in FIG. 4 (A). ..
Therefore, the rigidity of the front housing (5a) shown in FIG. 4A is increased by the plurality of heat radiation fins (5g), vibration is reduced, and pump noise is reduced.
Further, the engine cooling water (4) leaking from the bearing boss (5c) shown in FIGS. 2 and 4A is radially dispersed by the guidance of the plurality of heat radiation fins (5g) shown in FIG. 4A. Concentrated contamination around the water pump (1) by the leaked engine cooling water (4) can be avoided.

The low friction film (33) shown in FIG. 4 (C) is formed of a film of a material selected from a resin containing a solid lubricant, a fluororesin, a diamond-like carbon, molybdenum disulfide, graphite, a manganate phosphate salt, and chromium. Has been done. Therefore, the low friction film (33) can be easily formed by surface treatment.

Examples of the solid lubricant include inorganic solid lubricants such as transition metal oxides and graphite.
Examples of the resin include polyamide resin, epoxy resin, phenol resin, silicone resin, and polyimide resin.

As shown in FIG. 4C, the plurality of low friction coatings (33) and (33) are dispersed and arranged in a spot shape, and the interfilm groove (34) is formed in a mesh shape.
The plurality of low friction coatings (33) and (33) are all formed in a regular hexagonal shape.
The plurality of low friction coatings (33) and (33) are not limited to the regular hexagonal shape, but may have various polygonal shapes and circular shapes.
When the impeller (7) rotates in the direction of the arrow (7a) on the left side of FIG. 4 (C), the engine cooling water (4) flows in the interfilm groove (34) as shown by the arrow (4a).

(1) ... water pump, (2) ... combustion chamber, (3) ... cooling water jacket, (4) ... engine cooling water, (5) ... pump housing, (6) ... rotary shaft, (7) ... impeller, (8) ... base plate, (9) ... blade, (9a) ... centrifugal force, (10) ... crankshaft, (11) ... urging means, (11a) ... urging force, (12) ... lying posture, (13) ) ... Standing posture, (15) ... Locked part, (16) ... Disproportionate force.

Claims (2)

A water pump (1) and a cooling water jacket (3) around the combustion chamber (2) are provided so that the engine cooling water (4) circulates between the water pump (1) and the cooling water jacket (3). Configured
The water pump (1) includes a pump housing (5), a rotating shaft (6) inserted in the pump housing (5), and an impeller (7) attached to the rotating shaft (6) in the pump housing (5). )
The impeller (7) includes a base plate (8) mounted in a posture orthogonal to the rotation axis (6) and blades (9) provided on the base plate (8), and the impeller (7) is a crankshaft (10). The engine cooling water (4) is configured to be pumped by the blades (9) in the centrifugal direction of the impeller (7).
The blades (9) are undulatingly attached to the base plate (8), and are urged in a prone position by the urging force (11a) of the urging means (11).
When the engine speed is low, the blades (9) are placed in the prone position (12) due to the unbalanced force (16) based on the urging force (11a) of the urging means (11) and the centrifugal force (9a) applied to the blades (9). Become
At high engine speed, the disproportionate force (16) causes the blades (9) in the lying position (12) to approach the standing position (13) along the direction parallel to the rotation axis (6). A water-cooled engine that features that. In the engine according to claim 1,
The blade (9) is provided with a locked portion (15), and when the engine speed exceeds a predetermined rotation speed, the locked portion (15) is locked to the base plate (8), and the blade (9) is in an upright posture (9). A water pump for a water-cooled engine, characterized in that it is configured to maintain 13).

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