JPS6332333Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine cooling system, and more particularly to an improved engine cooling system that can improve both water injection performance and warm-up performance.

Conventionally, a cooling device as shown in FIG. 1 is well known. That is, it has a radiator 1 and water jackets 2A and 2B, and a water pump 3 is disposed at the inlet of the water jacket 2A to forcefully circulate a coolant (water, antifreeze, etc.) to the engine (not shown). This is a device to prevent overheating.

On the other hand, in order to promote warm-up of the engine, a thermostat housing 5 that houses the thermostat 6 is usually provided above the position of the cylinder head 4, and the lower part of the thermostat housing 5 and the water pump 3 are The water pump 3 is connected to the inlet of the engine by a main bypass passage 7, and while the engine is cold, the coolant is sucked into the water pump 3 through the main bypass passage 7 and circulated, but the coolant is not sent to the radiator 1. .

By the way, when injecting water into the engine, it is necessary to bleed air from the water jackets 2A and 2B. For this purpose, the thermostat 6 is provided with an air vent hole 6A. The larger the air bleed hole 6A is, the faster the air bleeds out and the shorter the water injection time to the engine.

However, if the air vent hole is made larger in this manner, a large amount of cooling water heated by the engine flows into the radiator 1 when the engine is operating, resulting in a decrease in warm-up performance. That is, when the water injection performance is improved, the warm-up performance is reduced, and conversely, when the warm-up performance is improved, the water injection performance is reduced.

An object of the present invention is to provide an improved engine cooling system that overcomes the drawbacks of conventional cooling systems and can improve both water injection performance and warm-up performance.

In order to achieve this object, the present invention attaches to the cylinder head a thermostat housing that houses the thermostat located above the water jacket, and connects the lower part of the thermostat housing with the inlet of the water pump. In an engine cooling system connected by a main bypass passage, a sub-bypass passage having a smaller diameter than the main bypass passage is provided by connecting the upper part of the thermostat housing with the inlet of the water pump or the middle of the main bypass passage; , the sub-bypass passage is also communicated with a passage connecting the thermostat housing and the radiator.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 2 is a longitudinal cross-sectional view of a cooling device according to an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of essential parts near the thermostat housing.

As shown in FIG. 2, in the cooling system of the present invention, a sub-bypass path 9 having a smaller diameter than the main bypass path 7 is connected to the upper part of the thermostat housing 5 near the mounting part of the thermostat 6 and the inlet of the water pump 3. It is provided by connecting them. Note that this sub-bypass path 9 may be connected to the main bypass path 7.

As shown in FIG. 3, the sub-bypass passage 9 also communicates with a passage 10 connecting the thermostat housing 5 and the radiator 1 via an air vent hole 9B. This air vent hole 9B is the sub-bypass path 9
A smaller diameter is preferable. Note that the present invention uses a thermostat 6 that does not have an air vent hole in its main body.

Next, the operation of the cooling device of the present invention having such a configuration will be explained.

First, when filling water, use water jackets 2A and 2.
The air in B escapes from the inlet 9A of the sub-bypass passage 9 provided at the upper part of the thermostat housing 5 to the passage 10 through the air vent hole 9B. Therefore, water injection performance is improved.

Also, during warm-up operation, water jacket 2
Most of the cooling water that has entered the thermostat housing 5 from A and 2B is sucked into the water pump 3 side through the main bypass path 7. At this time, some of the cooling water also flows to the sub-bypass path 9, but due to flow path resistance, this cooling water is also sucked into the water pump 3 side, which has a stronger suction force than the radiator, and circulates through the engine. Therefore, leakage of cooling water to the passage 10 side is almost eliminated, and warm-up performance is improved.

As explained above, since the cooling device of the present invention has the above configuration, it can satisfy both water injection performance and warm-up performance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional cooling device.
FIG. 2 is a longitudinal cross-sectional view of a cooling device according to an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of essential parts near the thermostat housing. 1...Radiator, 2A, 2B...Water jacket, 5...Thermostat housing, 6
...Thermostat, 7...Main bypass path, 9...
...Sub-bypass road, 9A...Sub-bypass road entrance, 9
B... Air vent hole, 10... Passage.

Claims (1)

[Scope of utility model registration request] A thermostat housing containing a thermostat is attached to the cylinder head so as to be located above the water jacket, and the lower part of the thermostat housing and the inlet of the water pump are connected by a main bypass path to cool the engine. In the device, a sub-bypass path having a smaller diameter than the main bypass path is provided to connect the upper part of the thermostat housing and the inlet of the water pump or the middle of the main bypass path, and
An engine cooling device in which the sub-bypass passage is also connected to a passage connecting a thermostat housing and a radiator.