JPH06281538A - Method of inspecting engine cooling system - Google Patents

Abstract

PURPOSE:To insect an operating condition of a thermostat valve in an engine cooling system when testing ignition of the engine., CONSTITUTION:A cooling water circulation passage 5 that circulates the cooling water discharged from a water jacket of an engine 1 is fed back to the water jacket is formed. Consequently, while ignition testing of the engine is performed, an operating condition of a thermostat valve 8 of the water jacket under the condition that the temperature of the circulating cooling water is rising, is observed. After the observation, the circulation passage is switched so that the cooling water is supplied from a by-pass passage 11 of a cooling water supply passage 4 to the water jacket and is discharged to a drainage passage 7 via the cooling water circulation passage 5 and s9olenoid valve 6. The operation of the thermostat valve 8 is detected by means of a thermometer 13 placed in a connection passage 9 connected to the thermostat valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a cooling system of an engine, and more particularly to a method for inspecting an operating state of a thermostat valve.

[0002]

2. Description of the Related Art An engine assembled on a production line is subjected to an ignition test in the next inspection process to inspect whether it is normally operated. At this time, the cooling system of the engine is also inspected at the same time, but conventionally, for cooling the engine during the ignition test, cooling water heated to a constant temperature (for example, 65 ° C.) in the water tank is supplied into the water jacket. This cooling water temperature is controlled by the operating temperature of the thermostat of the water jacket (for example, 9
Since it does not exceed 0 ° C), the operating state of the thermostat valve cannot be checked at this stage, and the only inspection item for the cooling system is to check for water leaks.

[0003]

Therefore, there is a problem that the inspection of the operating state of the thermostat valve must be performed after the assembled vehicle is assembled. In view of such a current situation, an object of the present invention is to enable the operating state of a thermostat valve of a water jacket to be inspected at the same time as an engine ignition test.

[0004]

According to a method for inspecting an engine cooling system according to the present invention, an engine ignition is performed by forming a cooling water recirculation passage for returning the cooling water discharged from the water jacket of the engine to the water jacket again. After conducting a test and confirming the operating state of the water jacket thermostat valve due to the rise in the temperature of the circulating cooling water, the cooling water flow path is switched and the cooling water is supplied from the cooling water supply passage to the water jacket. It is characterized in that the gas is discharged through the reflux passage.

More specifically, an engine cooling system inspecting method according to the present invention comprises a temperature detecting means for detecting the temperature of cooling water flowing out from the thermostat valve when the thermostat valve is opened. It is characterized by confirming the operating state of and immediately switching the flow path of the cooling water.

[0006]

In the present invention, an engine ignition test is conducted by forming a cooling water recirculation passage for circulating the cooling water discharged from the engine water jacket to the water jacket again, so that the temperature of the circulating cooling water gradually rises. , When it reaches the operating temperature of the thermostat valve, the thermostat valve is activated. After confirming the operation of the thermostat valve, another cooling water having a low temperature (for example, 65 ° C.) is caused to flow from the cooling water supply passage into the water jacket, and the inspection is further continued if necessary. The operation of the thermostat valve can be confirmed by detecting the temperature of the cooling water flowing out from the thermostat valve.

On the other hand, if the circulating cooling water reaches the operating temperature of the inlet thermostat valve, but the thermostat valve does not operate normally, the malfunction is confirmed and the cooling water having a low temperature is continuously supplied from the cooling water supply passage. Run into the water jacket, judge that the thermostat is abnormal, and end the test. In addition, the non-operation of the thermostat valve,
This can be confirmed by detecting the temperature of the cooling water in the cooling water return passage.

[0008]

EXAMPLES The present invention will be described in detail. The inspection apparatus shown in FIG. 1 is an apparatus for inspecting a cooling system which is connected to a water jacket of an engine 1 used for an ignition test. A water tank 2 for storing and heating to a constant temperature (for example, 65 ° C.), and an engine 1 from the water tank 2 via a three-way valve 3
A cooling water supply passage 4 for supplying cooling water to the water jacket, and a cooling water return passage 5 for returning the cooling water discharged from the water jacket to the water jacket via the three-way valve 3 again. Here, the three-way valve 3
Has a function of switching the cooling water flow path entering the water jacket to either the cooling water supply passage 4 side or the cooling water return passage 5 side.

Further, the above-mentioned inspection device is provided with the cooling water return passage 5
There is provided a drainage passage 7 for returning the cooling water discharged from the tank to the water tank 1 through the 2-port solenoid valve 6 (normally open), and a connection passage 9 connecting the thermostat valve 8 of the water jacket and the drainage passage 7. Further, the cooling water supply passage 4 is bypass-connected in front of the three-way valve 3 and is a 2-port solenoid valve 10.
The bypass passage 11 is provided so that the cooling water can be supplied to the water jacket through (always closed).

A water temperature gauge 1 with a timer is provided in the reflux passage 5.
2 is installed, the water temperature gauge 12 confirms the passage of cooling water immediately after the start of the test, issues a signal after a predetermined time to operate the solenoid valve 6, and at the same time switches the three-way valve 3 to the cooling water recirculation passage 5 side. Further, it has a function of detecting an increase (for example, 85 ° C.) or a decrease in the temperature of the cooling water, turning on or off the patrol light P, and sounding an alarm device when overheating occurs. Further, a water temperature gauge 13 is installed in the connection passage 9, detects the temperature of the cooling water flowing out from the thermostat valve 8 that operates (for example, 90 ° C.) when the temperature of the cooling water rises, and issues a signal to operate the solenoid valve 10. At the same time, the solenoid valve 6 is deactivated.

The solenoid valve 10 is deactivated in response to the engine stop signal, and at the same time, the three-way valve is switched to the initial state (on the side of the cooling water supply passage 4). In FIG. 1, 14 is a limit switch that detects switching of the three-way valve, 15 and 16 are fluid sensors, 17 is a blind plug, and 18, 1
Reference numeral 9 is an air bleeding check valve, 20 to 22 are auxiliary valves provided when the solenoid valve 6 fails, and 23 is a drain groove.

Now, the operation procedure of the above-mentioned detecting device will be described. First, the three-way valve 3 is in the cooling water supply passage 4 side, the solenoid valves 6 and 10 are in the non-operating state, and the heated cooling water in the water tank 1 is After passing through the cooling water supply passage 4 and the three-way valve 3 into the water jacket of the engine 1, the cooling water recirculation passage 5,
It flows through a path called a drainage passage 7 via the solenoid valve 6. When the passage of the cooling water is confirmed by the water temperature gauge 12 of the cooling water return passage 5, the timer is activated, the solenoid valve 6 is activated after a lapse of a predetermined time, and the three-way valve 3 is switched to the side of the cooling water return passage 5 and the water tank 2 The supply of cooling water from is stopped.

Next, when the engine is ignited, the cooling water circulates in the closed circuit consisting of the water jacket and the cooling water recirculation passage 5 by the force of the pump in the water jacket, and the temperature gradually rises. When the thermometer 12 detects a predetermined temperature rise of the cooling water (for example, 85 ° C.), the patrol light P is turned on. Then, when the temperature of the cooling water reaches the operating temperature of the thermostat (for example, 90 ° C.), the thermostat valve 8 opens, and a part of the cooling water flows into the connection passage 9, which is detected by the thermometer 13 and the fluid sensor 16. It will be.

Upon receipt of a signal from the thermometer 13, the solenoid valve 1
When the solenoid valve 6 is deactivated, the solenoid valve 6 is deactivated, and the cooling water in the water tank 2 enters the water jacket through the bypass passage 11 and the solenoid valve 6 through the cooling water return passage 5.
From the drainage passage 7. At this time, the thermostat valve 8 is cooled and closed by the cooling water from the water tank 2. Further, when the cooling water from the water tank 2 flows through the water jacket to the cooling water return passage 5, the thermometer 12 detects the temperature drop and stops the patrol light P.

When the predetermined ignition test is completed, the engine is stopped. At this time, the operation of the solenoid valve 10 is released, the three-way valve is also switched to the cooling water supply passage 4 side, and returns to the initial state.

In the unlikely event that the thermostat valve does not operate normally, the temperature of the cooling water circulating in the closed circuit composed of the water jacket and the cooling water return passage 5 becomes
The temperature continues to rise above the thermostat operating temperature, which can be detected by the thermometer 12, and an overheat signal from the thermometer 12 causes an alarm to sound an abnormality in the thermostat valve. Subsequently, when the engine is stopped, the solenoid valve 6 and the three-way valve 3 return to the initial state, and the cooling water in the water tank 2 flows into the water jacket through the cooling water supply passage 4 and into the drain passage 7 through the solenoid valve 6.

[0017]

According to the present invention, the operating state of the thermostat valve of the water jacket of the engine can be inspected at the same time as the ignition test.

[Brief description of drawings]

FIG. 1 is a cooling water path diagram of an inspection device for an engine cooling system.

[Explanation of symbols]

 1 engine 2 water tank 3 three-way valve 4 cooling water supply passage 5 cooling water return passage 6 2 port solenoid valve (normally open) 7 drainage passage 8 thermostat valve 9 connection passage 10 2 port solenoid valve (normally closed) 11 cooling water supply passage Bypass passage 12, 13 Thermometer

Claims (2)

[Claims] 1. A thermostat valve of a water jacket according to an increase in temperature of the circulating cooling water, wherein an ignition test of the engine is conducted by forming a cooling water recirculation passage for recirculating the cooling water discharged from the engine water jacket to the water jacket. After confirming the operating state of
A method for inspecting a cooling system of an engine, characterized in that the flow path of the cooling water is switched so that the cooling water is supplied from the cooling water supply passage to the water jacket and is discharged through the cooling water return passage. 2. A temperature detecting means for detecting the temperature of the cooling water flowing out from the thermostat valve when the thermostat valve is opened, the operating state of the thermostat valve is confirmed, and the circulation path of the cooling water is switched. And the inspection method of the engine cooling system.