JP3185581B2 - Internal combustion engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a cooling system circuit in a cooling device for a water-cooled internal combustion engine.

[0002]

2. Description of the Related Art In a conventional cooling device for a water-cooled internal combustion engine, as shown in FIG.
And an inflow passage 14 from the outlet 11a to the water jacket 4 in the engine body 1 (cylinder block 2 and cylinder head 3) through the thermostat 12 and the water pump 13, and the water jacket 4 and the radiator from the water jacket 4. And an outflow passage 18 reaching an inlet 11b of the eleventh. In this cooling device, a bypass passage B is connected between the outflow passage 18 of the main cooling passage M and the thermostat 12, and a heater passage H is provided in addition to the bypass passage B. The heater path H extends from the outflow passage 18 to the thermostat 12 via the heater 19. During the warm-up operation, the cooling water does not flow to the radiator 11 due to the switching of the thermostat 12, but circulates through the bypass B and the heater H
Also flows. After the completion of the warm-up operation, the switching of the thermostat 12 causes the cooling water to circulate in the main cooling passage M and also to the bypass passage B and the heater passage H.

[0003]

In the water jacket 4, cooling water is always supplied to the cylinder head exhaust-side water jacket 7, the cylinder head intake-side water jacket 8, regardless of the warm-up operation or after the warm-up operation is completed.
It sequentially passes through the water jacket 9 on the cylinder block exhaust side and the water jacket 10 on the cylinder block intake side.

However, in order to increase the temperature of the cooling water flowing through the heater 19 during the warm-up operation in which the temperature of the cooling water is relatively low, the water jackets 7, 8, 9, 1 are required.
0, the bypass B, the outflow passage 18 and the inflow passage 14 all require the wall temperature and the water temperature to rise simultaneously.
Therefore, it takes time to obtain sufficient heater performance.

In the conventional cooling device for an internal combustion engine disclosed in Japanese Utility Model Laid-Open Publication No. 56-111217, a heater path is provided in addition to the main cooling path and the bypass path, and the same problem as described above occurs.

An object of the present invention is to improve heater performance by improving a heater path and a water jacket.

[0007]

SUMMARY OF THE INVENTION A cooling device for an internal combustion engine according to the present invention is configured as follows. A main cooling path in which cooling water returns from the radiator to the radiator through a cylinder head exhaust side water jacket, a cylinder head intake side water jacket, and a cylinder blocked water jacket in the engine body in order, and the cooling water does not pass through the radiator. A bypass that circulates through a water jacket in the body. A switching valve is provided in an inflow passage between the radiator and the upstream port of the cylinder head exhaust-side water jacket, and a state in which cooling water is circulated only through a water jacket and a bypass in the engine body; The state can be switched to a state in which the cooling water can be circulated in the bypass passage while the cooling water is circulated in the passage.

A heater path is provided between the switching valve or an inflow passage extending from the switching valve to an upstream port of the cylinder head exhaust-side water jacket and a downstream side of the cylinder head exhaust-side water jacket. I have. A control valve is provided in a communication passage between the downstream side of the cylinder head exhaust-side water jacket and the upstream side of the cylinder head intake-side water jacket at a predetermined water temperature or lower.

[0009]

When the temperature of the cooling water is lower than the switching temperature of the control valve during the warm-up operation, the cooling water does not flow to the radiator of the main cooling passage, and the water jacket in the cylinder head exhaust side water jacket in the engine body. Through the heater path.

After the completion of the warming-up operation, the switching valve operates to allow the cooling water to flow through the radiator in the main cooling path,
It also flows to the bypass path and the heater path.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cooling device for a water-cooled internal combustion engine according to one embodiment of the present invention will be described below with reference to FIG.

Inside the cylinder block 2 and the cylinder head 3 of the engine body 1, a water jacket 4 schematically indicated by an arrow is provided. The water jacket 4 is a cooling water passage for cooling the cylinder bore wall surface and the combustion chamber. The water jacket 4 is divided into a cylinder head water jacket 5 and a cylinder block water jacket 6. The cylinder head water jacket 5 has an exhaust side 7 and an intake side 8
The cylinder block water jacket 6 is divided into an exhaust side 9 and an intake side 10. A radiator 11 is provided in front of the engine body 1.

A main cooling passage M is provided with a radiator 11, an inflow passage 14 extending from an outlet 11a thereof to an upstream port 7a of the cylinder head exhaust side water jacket 7 through a thermostat 12 (switching valve) and a water pump 13. The cylinder head exhaust-side water jacket 7, a communication path 15 extending from the downstream port 7b to the upstream port 8a of the cylinder head intake-side water jacket 8, the cylinder head intake-side water jacket 8, and the downstream port. A communication path 16 extending from the outlet 8b to the upstream port 9a of the cylinder block exhaust-side water jacket 9, the cylinder block exhaust-side water jacket 9, and an upstream port of the cylinder block intake-side water jacket 10 from the downstream port 9b; Communication path 17 leading to 10a and this cylinder block A gas-side water jacket 10, the inlet 11b of the radiator 11 from the downstream side opening 10b
Outflow passage 18 leading to

The bypass B is connected between the outflow passage 18 and the thermostat 12. The heater path H is connected through a heater 19 between the thermostat 12 and the downstream port 7b of the water jacket 7 on the cylinder head exhaust side.

In the thermostat 12, a switching temperature is set, and the valve opens and closes according to the switching temperature. If the cooling water temperature is lower than the switching temperature, the inlets 12a, 12b of the thermostat 12
And the outlet 12c communicate with the inlet 12d and the outlet 1
2c is closed, and the cooling water flows from the bypass passage B and the heater passage H through the suction force of the water pump 13 to the inlets 12a, 12c.
It reaches the water inlet 13a of the water pump 13 through the outlet 12b and the outlet 12c. When the temperature of the cooling water is higher than the switching temperature, the communication between the inlet 12d and the outlet 12c of the thermostat 12 is also performed, and the cooling water flows from the outlet 11a of the radiator 11 to the inlet 12a by the suction force of the water pump 13. The cooling water flows to the suction passage 13a of the water pump 13 through the outlet 12c, and the cooling water also flows to the bypass passage B and the heater passage H.

In the communication passage 15 extending from the downstream port 7b of the cylinder head exhaust side water jacket 7 to the upstream port 8a of the cylinder head intake side water jacket 8, the downstream port 7b and the upstream port 8a are shut off. A control valve 20 (thermostat) is provided. In this control valve 20, a switching temperature is set, and the valve opens and closes according to the switching temperature. When the cooling water temperature is lower than the switching temperature, the communication path 15 is shut off, and cooling is performed from the downstream port 7b of the cylinder head exhaust-side water jacket 7 to the upstream port 8a of the cylinder head intake-side water jacket 8. Water does not flow. Therefore, the cooling water flows only from the downstream side port 7b of the cylinder head exhaust side water jacket 7 to the heater path H.

When the cooling water temperature is lower than the switching temperature of the control valve 20 during the warm-up operation, the control valve 20 is closed and the thermostat 12 is switched and closed. Therefore, the cooling water does not flow to the radiator 11 of the main cooling path M, but flows only to the heater path H through only the cylinder head exhaust side water jacket 7 of the water jacket 4 in the engine body 1.

If the cooling water temperature is higher than the switching temperature of the control valve 20 during the warm-up operation, the control valve 20
Is opened, and the thermostat 12 is switched and closed. Therefore, the cooling water does not flow to the radiator 11 of the main cooling path M, but reaches the thermostat 12 from the water jacket 4 in the engine body 1 through the heater path H, the outflow path 18 and the bypass path B, and passes through the water pump 13. Return to the water jacket 4.

After completion of the warm-up operation, the control valve 2
When 0 is opened, the thermostat 12 is switched and opened. Therefore, the cooling water flows through the main cooling passage M and also flows into the bypass passage B and the heater passage H.

This embodiment has the following features (a) to (d). (A) The water jacket 4 on the cylinder head exhaust side of the water jacket 4 in the engine body 1 is formed because the exhaust gas has heat at the exhaust port of the cylinder head 3 and the volume of the cylinder head 3 is small. The cooling water temperature is more likely to rise than the other water jackets 8, 9, and 10 of the water jacket 4 in the engine body 1. Further, the outflow passage 18 and the bypass passage B are easily exposed to outside air and are easily cooled. Therefore, when the cooling water temperature is low during the warm-up operation, the cooling water is circulated only through the heater path H through the cooling water only through the water jacket 7 on the cylinder head exhaust side. Therefore, the temperature of the cooling water is easily increased, and the thermal efficiency of the heater can be improved. After that, when the cooling water temperature rises to some extent during the warm-up operation, or when the warm-up operation is completed,
The normal cooling water control described above is performed.

(B) Since there is almost no flow of cooling water except for the cylinder head exhaust side water jacket 7 and the heater path H, the temperature of only the cooling water layer near the boundary with the cylinder block 2 etc. rises and moves away therefrom. The temperature of the central cooling water layer is unlikely to rise. Therefore, when the temperature of the cylinder block 2 and the like rises, the heat of the cylinder block 2 and the like is effectively conducted to the cooling water flowing in the cylinder head exhaust-side water jacket 7 and exchanging heat with the heater 19, thereby reducing the heater thermal efficiency. Can be improved.

(C) Due to the adiabatic effect of the cylinder block 2 and the like described in (b), the propagation of the combustion flame is promoted, and the end-gas emission is reduced. (D) Thermostat 12 is exit 1 of radiator 11
It is provided in the inflow passage 14 between the upper side port 1 a of the cylinder head exhaust side water jacket 7 and the cylinder head exhaust side water jacket 7. Therefore, when the thermostat 12 is closed, the cooling water from the radiator 11 which is easily cooled can be surely shut off, and the flow of the cooling water in the radiator 11 and the bypass passage B is stopped, so that only the cylinder head exhaust side water jacket 7 and the heater passage H are provided. It is easy to circulate the cooling water.

In addition to the present embodiment, the following constructions (a) to (c) may be adopted. (A) Instead of the control valve 20 (thermostat) of the embodiment, a switching valve switched by a temperature sensor is used.
In this case, the temperature sensor detects the cooling water temperature at a predetermined position,
The detected water temperature data is output to the controller. The controller stores set water temperature data for switching the switching valve between the open state and the closed state. The controller compares the detected water temperature data with the set water temperature data, and when the detected water temperature data becomes equal to or lower than the set water temperature data, sets the switching valve to the shut-off state. Further, instead of the thermostat 12 of the above embodiment, a similar switching valve switched by a temperature sensor is used.

(B) The control valve 20 (thermostat) of the above-described embodiment can take only two stages, that is, an open state and a closed state. The flow rate of the cooling water flowing through the passage 15 is adjusted in multiple stages.

(C) In the cooling device of the above embodiment, since the heat of the exhaust gas is actively removed, the temperature rise of the catalyst in the exhaust pipe may be delayed. As a means to supplement this,
For example, when an electric heater is connected to the catalyst and cooling water is circulating only in the water jacket 7 on the cylinder head exhaust side, the electric heater is energized and heated,
A decrease in the temperature rise of the catalyst can be prevented.

[0026]

According to the cooling device for an internal combustion engine of the present invention, when the cooling water temperature is low during the warm-up operation, the cooling water is passed only through the water jacket on the cylinder head exhaust side where the cooling water temperature tends to rise. Since the heater is circulated only to the heater, the heater performance can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram illustrating a cooling device for an internal combustion engine according to an embodiment.

FIG. 2 is a schematic circuit diagram showing a conventional cooling device for an internal combustion engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine body, 2 ... Cylinder block, 3 ... Cylinder head, 4 ... Water jacket, 5 ... Cylinder head water jacket, 6 ... Cylinder block water jacket, 7 ... Cylinder head exhaust side water jacket, 8 ... Cylinder head Inlet side water jacket, 9 ... Cylinder block exhaust side water jacket, 10 ... Cylinder block intake side water jacket, 11 ... Radiator, 12 ... Thermostat (switching valve), 13 ... Water pump, 14 ... Inflow passage, 15 …
Communication passage, 18 outflow passage, 19 heater, 20 control valve, M main cooling path, B bypass path, H heater path.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01P 7/16 504 F01P 7/16 502 F01P 7/16 505 F01P 3/02

Claims (1)

(57) [Claims] 1. A main cooling path for returning cooling water from a radiator to a radiator through a cylinder head exhaust side water jacket, a cylinder head intake side water jacket, and a cylinder block water jacket in an engine body in order, and the cooling water passes through the radiator. A bypass passage that circulates through a water jacket in the engine body without being provided in an inflow passage between the radiator and an upstream port of a cylinder head exhaust water jacket, and a water jacket and a bypass in the engine body. A cooling device for an internal combustion engine including a switching valve capable of switching between a state in which cooling water is circulated only in a path and a state in which cooling water is circulated in the main cooling path and a state in which cooling water can be circulated in a bypass path. The switching valve or the switching valve and the syringe A heater path is provided between an inflow passage leading to an upstream port of the damhead exhaust-side water jacket and a downstream side of the cylinder head exhaust-side water jacket, and a downstream side of the cylinder head exhaust-side water jacket and a cylinder head intake-side water jacket. A cooling device for an internal combustion engine, wherein a control valve for shutting off the communication passage at a predetermined water temperature or lower is provided in a communication passage between the engine and the upstream side of the internal combustion engine.