(1) Field of the Invention
The present invention relates to an engine water-cooling device.
(2) Description of Related Art
Conventionally, as an engine water-cooling device, there is a device in which a bypass passage includes only a bypass pipe exposed outside an engine.
In the conventional engine water-cooling device, when the engine cooling water passes through the bypass passage, heat of the engine cooling water radiates. A water temperature of the engine cooling water reduces, and the warming-up efficiency of the engine is low.
An object of the present invention is to provide an engine water-cooling device that can increase warming-up efficiency of an engine.
Matters specifying the present invention are as follows.
An engine water-cooling device including: an intra-head cooling water jacket in a cylinder head; a thermostat; a bypass passage; a radiator; and a cooling water pump, and
configured such that engine cooling water in the intra-head cooling water jacket flows back to the cooling water pump via the bypass passage bypassing the radiator and when a water temperature of the engine cooling water detected by the thermostat exceeds a predetermined value, the thermostat causes the engine cooling water in the intra-head cooling water jacket to flow back to the cooling water pump via the radiator,
wherein the engine water-cooling device includes a thermostat housing that houses the thermostat, the thermostat housing is mounted to a front wall of the cylinder head in one side portion in a width direction of the cylinder head, the cooling water pump is mounted to a front wall of a cylinder block in a central portion in a width direction of the cylinder block,
the bypass passage includes an intra-head bypass passage in the cylinder head, and the intra-head bypass passage includes a width-direction passage portion extending from a position behind the thermostat housing to a position behind and above the cooling water pump.
The invention exerts the following effect.
The engine cooling water passing through the relatively long width-direction passage portion receives heat from the cylinder head. Reduction in the water temperature of the engine cooling water is suppressed, and it is possible to increase the warming-up efficiency of the engine.
A general outline of the engine is as follows.
As shown in
The cylinder block (6) is a casting having an upper cylinder portion (6a) and a lower crankcase (6b) integrated with each other.
In the embodiment, a direction in which a crankshaft (10) extends is defined as a front-back direction, one side of the front-back direction is defined as the front, and the other side is defined as the back.
A general outline of the engine water-cooling device is as follows.
As shown in
The water-cooling device is configured such that engine cooling water (15) in the intra-head cooling water jacket (12) flows back to the cooling water pump (3) via the bypass passage (4) bypassing the radiator (18) and when a temperature of the engine cooling water (15) detected by the thermostat (1) exceeds a predetermined value, the thermostat (1) causes the engine cooling water (15) in the intra-head cooling water jacket (12) to flow back to the cooling water pump (3) via the radiator (18).
Details of the water-cooling device are as follows.
As shown in
As shown in
The bypass passage (4) includes an intra-head bypass passage (4a) in the cylinder head (5), and the intra-head bypass passage (4a) has a width-direction passage portion (4c) extending from a position behind the thermostat housing (2) to a position behind and above the cooling water pump (3). For this reason, the engine cooling water (15) passing through the relatively long width-direction passage portion (4c) receives heat from the cylinder head (5). Reduction in the water temperature of the engine cooling water (15) is suppressed, and it is possible to increase the warming-up efficiency of the engine.
As shown in
For this reason, the inside of the thermostat housing (2) can be made into a simple structure of having only the partition wall (7) including the bottom bypass valve orifice (7a), and it becomes easy to perform demolding and the like during casting and to manufacture the thermostat housing (2).
Further, simply mounting the thermostat housing (2) to the front wall (5a) of the cylinder head (5) completes the communication work between the cylinder head (5) and the thermostat housing (2).
Furthermore, the engine cooling water (15) introduced forward into the thermostat chamber (8) passes downward through the lower bottom bypass valve orifice (7a), reverses into a backward direction in the bottom bypass chamber (9), and smoothly passes through the thermostat housing (2) without taking a complicated meandering route. For this reason, resistance to passage of the engine cooling water (15) in the thermostat housing (2) is small, and it is possible to reduce the horsepower loss of the engine.
As shown in
The thermostat (1) is housed in the thermostat chamber (8). The bottom bypass valve orifice (7a) is configured to be opened and closed by a bottom bypass valve (1a) of the thermostat (1). The outlet (12a) of the intra-head cooling water jacket (12) and the inlet (8a) of the thermostat chamber (8) overlap and communicate with each other, and the outlet (9a) of the bottom bypass chamber (9) and the inlet (4b) of the bypass passage (4) overlap and communicate with each other.
The thermostat (1) is of a bottom bypass type.
As shown in
Note that as shown in
As shown in
When the temperature of the engine cooling water (15) in contact with the slider (26) increases, the wax in the slider (26) becomes liquefied and increases in volume. For this reason, the slider (26) slides toward the bypass valve orifice (7a), the main valve (1b) is opened, and an opening degree of the bottom bypass valve (1a) reduces. The engine cooling water (15) in the intra-head cooling water jacket (12) shown in
As shown in
The outlet (4h) of the bypass passage (4) and the inlet (3b) of the suction chamber (3a) of the cooling water pump (3) overlap and communicate with each other.
Next, a variation of the thermostat housing (2) shown in
As shown in
The heat insulating layer (14) is formed by a hollow air space in the front peripheral wall (2a) of the thermostat housing (2). For this reason, there is no fear of heat deterioration of the heat insulating layer (14) and it is possible to maintain a high heat insulating property of the heat insulating layer (14) for a long period.
As shown in
An upper face of the heat insulating layer (14) opens and this opening is covered with a flange of a main outlet pipe (27).
As shown in
In other words, the ceiling face (4d) of the width-direction passage portion (4c) slopes upward toward a lead-out end of a portion led out backward from an inlet (4b) of an intra-head bypass passage (4a).
For this reason, bubbles of steam generated in the width-direction passage portion (4c) by the heat received from the cylinder head (5) are released to the thermostat housing (2) along the ceiling face (4d) of the width-direction passage portion (4c), and the steam is less likely to be entrapped in the width-direction passage portion (4c). For this reason, entry of the heat from the cylinder head (5) to the engine cooling water (15) passing through the width-direction passage portion (4c) is not obstructed by the steam entrapment. Reduction in the water temperature of the engine cooling water (15) is suppressed, and it is possible to maintain a high warming-up efficiency of the engine.
As shown in
The bypass passage (4) is formed continuously by the intra-head bypass passage (4a) and the intra-block bypass passage (4e) and is not exposed outside an engine.
Next, a variation of the bypass passage (4) shown in
A bypass passage (4) shown in
The bypass passage (4f) outside the engine is a metal pipe provided between a cylinder head (5) and a cooling water pump (3), and one end portion of the bypass passage (4f) outside the engine is fitted in (press-fitted into) a front wall (5a) of the cylinder head (5). For this reason, the heat from the cylinder head (5) is transferred to the bypass passage (4f) outside the engine, and the engine cooling water (15) passing through the bypass passage (4f) outside the engine receives the heat from the cylinder head (5). Reduction in the water temperature of the engine cooling water (15) is suppressed, and it is possible to increase the warming-up efficiency of the engine.
As shown in
For this reason, the engine cooling water (15) passing through the bypass passage (4f) outside the engine is less likely to be cooled by the engine cooling air (13a). Reduction in the water temperature of the engine cooling water (15) is suppressed, and it is possible to increase the warming-up efficiency of the engine.
A forward bulging portion (5b) is formed in the front wall (5a) of the cylinder head (5), and an upper end portion of the bypass passage (4f) outside the engine is press-fitted into the bulging portion (5b). The air shielding wall (4g) is led out upward from the cooling water pump (3).
Number | Date | Country | Kind |
---|---|---|---|
2014-198030 | Sep 2014 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
1519155 | Moorhouse | Dec 1924 | A |
5970928 | Smietanski et al. | Oct 1999 | A |
Number | Date | Country |
---|---|---|
1143124 | Oct 2001 | EP |
1143124 | Oct 2003 | EP |
2001098944 | Apr 2001 | JP |
Entry |
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Extended Search Report issued Feb. 5, 2016 in EP Application No. 15178376.8. |
Number | Date | Country | |
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20160090895 A1 | Mar 2016 | US |