JPH0734173Y2 - Cooling device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a cooling device for an internal combustion engine, which preheats and cools an intake manifold and a carburetor in the internal combustion engine.

[Conventional technology]

From the outlet chamber with a bottom bypass type thermostat valve in the cylinder head, to the cooling water main circulation path from the radiator and cooling water pump to the cooling water jacket in the cylinder block, and from the outlet chamber to the suction side of the cooling water pump. In a cooling device in an internal combustion engine consisting of a cooling water bypass path, in the cooling water bypass path,
Performing intake air preheating by inserting the riser section in the intake manifold is a prior art technique.
It is well known in Japanese Patent Publication No. 59-54738.

It is also easy to insert the riser portion of the vaporizer into the bypass of the cooling water in order to prevent icing in the vaporizer.

[Problems to be solved by the device]

However, as described above, when the riser section of the intake manifold and the riser section of the carburetor are provided in the bypass path of the cooling water, the following problems occur.

That is, the cooling water is flowing in the cooling water bypass path until the temperature of the cooling water rises to the opening temperature of the bottom bypass type thermostat valve (for example, 80 ° C.). When the vaporizer is provided with a riser section, the vaporizer is heated more than necessary until the bottom bypass type thermostat valve is opened, and vapor of fuel is stored in the vaporizer. This occurs, which causes a so-called rough idle in which the fuel supply amount fluctuates, and further, the rotation speed during idling operation of the internal combustion engine fluctuates.

Therefore, in order to prevent this inconvenience, a temperature sensing valve that is closed at a temperature lower than the opening temperature of the bottom bypass type thermostat valve may be provided in the cooling water bypass path. The closing operation of the temperature sensing valve stops the flow of the cooling water in the cooling water bypass path, which causes a problem that the circulation of the cooling water through the bypass path is stopped and the bottom bypass type thermostat valve opens. The intake air preheating is stopped at the same time until the operation, and the effect of the intake air preheating is diminished.

According to the present invention, when the riser section of the intake manifold and the riser section of the carburetor are provided in the bypass path of the cooling water, the intake preheating for the intake manifold before the opening operation of the bottom bypass type thermostat valve is performed. It is intended to provide a cooling device which prevents excessive heating of a vaporizer in a secured state.

[Means for Solving the Problems]

To achieve this object, the present invention provides a main circulation path of cooling water from an outlet chamber with a bottom bypass type thermostat valve in a cylinder head, a radiator and a cooling water pump to a cooling water jacket in a cylinder block, and the outlet chamber. A cooling device in an internal combustion engine, comprising: a riser part in the intake manifold and a bypass path for cooling water to reach the suction side of the cooling water pump through the riser part in the carburetor; The bottom bypass type thermostat is connected to the suction side of the water pump via a communication passage, and at a portion of the cooling water bypass path from the outlet of the riser section of the carburetor to the suction side of the cooling water pump. And a configuration providing a temperature sensing valve to close at a temperature lower than the opening temperature of the bets valve.

[Function and effect of device]

According to this structure, the cooling water flows through the cooling water bypass path in a state where the temperature is lower than the opening temperature of the bottom bypass type thermostat valve, thereby heating the intake manifold and heating the carburetor. It can be carried out.

Then, when the temperature of the cooling water rises to a temperature close to the opening temperature of the bottom bypass type thermostat valve, the temperature sensing valve is closed, so that the flow of the cooling water to the riser section in the carburetor is stopped, while the outlet is closed. Since the cooling water in the chamber repeatedly circulates through the riser section in the intake manifold and is sucked into the cooling water pump via the communication passage, the circulation of the cooling water can be ensured and the intake manifold can be preheated.

In other words, it is possible to prevent the carburetor from being heated more than necessary under the condition that the intake preheat for the intake manifold is secured until the bottom bypass type thermostat valve is opened. In this state, the intake air preheating and the prevention of rough idle can be reliably achieved in the state where the circulation of the cooling water is secured until the opening operation is performed.

〔Example〕

Referring to the drawings, reference numeral 1 in the drawings denotes a cylinder block having a cooling water jacket 1a therein, and reference numeral 2 denotes a cylinder head having a cooling water jacket 2a therein, The cylinder head 2 is fastened to the upper surface of the cylinder block 1 so that the cooling water jacket 2a of the cylinder head 2 communicates with the cooling water jacket 1a of the cylinder block 1, and the cylinder head 2 has the cylinder An outlet chamber 3 communicating with a cooling water jacket 2a in the head 2 is provided, and a cooling water pump 4 for feeding cooling water into the cooling water jacket 1a in the cylinder block 1 is provided in the cylinder block 1. It is provided.

An intake manifold 5 having a carburetor 6 is connected to a side surface of the cylinder head 2, and the intake manifold 5 is connected to the intake manifold 5.
Is provided with a riser portion 7 for heating the intake manifold 5, and the vaporizer 6 is provided with a riser portion 8 for heating the vaporizer 6.

Between the outlet chamber 3 and the radiator 9,
The radiator 9 and the suction side of the cooling water pump 4 are connected to each other through circulation pipe lines 10 and 11 to form a main circulation path of the cooling water, while the outlet chamber 3 and the intake manifold are connected. 5 between the inlet of the riser section 7 of the intake manifold 5, the outlet of the riser section 7 of the intake manifold 5 and the inlet of the riser section 8 of the carburetor 6, and the outlet of the riser section 8 of the carburetor 6 and the cooling water pump 4 A bypass path dedicated to bypassing the cooling water is formed by connecting to the circulation pipe line 11 for the cooling water via the paths 12, 13, and 14, respectively.

In addition, when the temperature of the cooling water reaches a certain temperature (for example, 80 ° C.) in the outlet chamber 3, the circulation pipe 10 to the radiator 9 is opened, and at the same time, the intake manifold 5 is opened.
A bottom bypass type thermostat valve 15 is provided so as to close the passage 12 to the riser section 7.

Then, in the passage 14 from the outlet of the riser portion 8 of the carburetor 6 to the circulation pipeline 11 to the cooling water pump 4, a temperature appropriately lower than the valve opening temperature of the bottom bypass type thermostat valve 15 (for example, A temperature sensing valve 16 that is closed at 60 ° C. is provided, while a throttle orifice is provided between the passage 13 from the outlet of the riser portion 7 in the intake manifold 5 and the circulation pipe 11 to the cooling water pump 4. It is configured to be connected via a communication passage 17 provided with 18.

In this configuration, at the time of cold start of the internal combustion engine, in a state where the temperature of the cooling water is low, the bottom bypass type thermostat valve 15 closes the circulation pipe line 10 to the radiator 9 while the bottom bypass type thermostat valve 15 to the riser portion 7 in the intake manifold 5. aisle
Since 12 is opened, the cooling water in the cooling water jacket 2a of the cylinder head 2 flows from the outlet chamber 3 to the riser portion 7 in the intake manifold 5, the riser portion 8 in the carburetor 6, the cooling water pump 4, and the cylinder block 1. By repeating the circulation after returning to the cooling water jacket 2a of the cylinder head 2 after passing through the cooling water jacket 1a, intake preheating for the intake manifold 5 and heating of the carburetor 6 can be performed.

When the temperature of the cooling water rises to 60 ° C. after the start of the internal combustion engine, the temperature sensing valve 16 is closed to stop the flow of the cooling water to the riser portion 8 in the carburetor 6, so that the carburetor 6 is cooled. Although the heating is stopped, the cooling water from the outlet chamber 3 is connected to the communication passage with the throttle orifice 18.
Since it flows to the suction side of the cooling water pump 4 via 17,
Intake preheating for the intake manifold 5 is ensured.

When the temperature of the cooling water becomes higher, the bottom bypass type thermostat valve 15 operates to open the circulation pipe line 10 to the radiator 9 and close the passage 12 to the riser portion 7 in the intake manifold 5. Therefore, the cooling water in the cooling water jacket 2a of the cylinder head 2 is
After all, the circulation from the outlet chamber 3 through the radiator 9, the cooling water pump 4, and the cooling water jacket 1a in the cylinder block 1 to the cooling water jacket 2a of the cylinder head 2 is repeated.

The communication passage 17 may be configured as a small-diameter communication passage instead of providing the throttle orifice 18 therein.
Further, the communication passage 17 is not connected to the circulation pipe 11 to the cooling water pump 4 as in the above-described embodiment, but is connected to the passage 14 from the riser portion 8 in the carburetor 6 in relation to the passage. It may be configured to be connected on the downstream side of the temperature sensing valve 16 in 14.

[Brief description of drawings]

The drawings show the embodiments of the present invention. 1 ... Cylinder block, 2 ... Cylinder head, 3 ...
… Outlet chamber, 4… Cooling water pump, 5…
... intake manifold, 6 ... carburetor, 7 ... intake manifold riser section, 8 ... carburetor riser section, 9 ... radiator, 10,11 ... circulation pipeline for main circulation path, 12,13 , 14 …… Aisle for bypass route, 15
...... Bottom bypass type thermostat valve, 16 …… Temperature sensing valve, 17 …… Communication passage, 18 …… Throttle orifice.

Claims (1)

[Scope of utility model registration request] 1. A cooling water main circulation path from an outlet chamber with a bottom bypass type thermostat valve in a cylinder head to a cooling water jacket in a cylinder block via a radiator and a cooling water pump,
In a cooling device for an internal combustion engine, which comprises a cooling water bypass path from the outlet chamber to a suction side of the cooling water pump through a riser portion in an intake manifold and a riser portion in a carburetor, an outlet of the riser portion in the intake manifold And the suction side of the cooling water pump are connected via a communication passage, while the bottom portion is provided in a portion of the cooling water bypass route from the outlet of the riser section of the carburetor to the suction side of the cooling water pump. A cooling device for an internal combustion engine, comprising a temperature sensing valve which is closed at a temperature lower than a valve opening temperature of a bypass type thermostat valve.