JPH1089071A - Cooling water temperature controller of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve engine cooling property and heater performance by controlling cooling of the engine cooing water temperature of an automobile by two set temperatures. SOLUTION: A thermostat for controlling the engine cooling water temperature is constituted of a first thermostat 30 to be opened at the high temperature and a second thermostat 31 to be opened at the low temperature, and a solenoid valve 33 interposed between them is controlled by a heater switch 32. When a heater is used, the engine cooling water temperature is controlled by the first thermostat 30 having the high temperature, and heater performance is improved. When the heater is not used, the engine cooling water temperature is controlled by the second thermostat 31 having the low temperature, and engine cooling performance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling water temperature control device for use in a cooling system of an automobile engine.

[0002]

2. Description of the Related Art An automobile engine is cooled by circulating cooling water. That is, the water jacket of the engine and the radiator are connected by a closed circulation circuit, and the cooling water circulated by the water pump is cooled to an appropriate temperature. A thermostat is provided at the cooling water inlet of the radiator to control whether the radiator is passed or bypassed in accordance with the temperature of the cooling water so that the temperature of the circulating cooling water is kept constant.

FIG. 6 schematically shows a conventional cooling system for an automobile engine generally used. In this figure, 1 is an engine, 2 is an intake manifold, 3 is a cylinder block, and 4 is a water pump driven by a crankshaft of the engine 1. The outlet side of the water pump 4 is connected to a thermostat device 6 by a water channel 5.

The outlet side of the thermostat device 6 is branched into two water paths 7 and 8, one of which is connected to the inlet side of the radiator 9, and the other of which is connected to the inlet side of the heater unit 10. The water channel 11 connected to the outlet side of the radiator 9 and the water channel 12 connected to the outlet side of the heater unit 10 are both connected to a water channel 13 whose tip is connected to the inlet side of the water pump 4.

In the thermostat device 6, a thermostat case 14 has a partition wall 15, which is defined by a cooling water introduction chamber 16 and a cooling water discharge chamber 17 of the engine. The two water discharge chambers 17 communicate with each other when a thermostat 18 provided therebetween opens the valve.

Although the thermostat 18 is shown schematically, when the thermowax 19 expands, the valve body 21 moves via a rod 20 which moves downward in the figure, and when a gap is formed between the thermostat 19 and the partition wall 15, The cooling water introduction chamber 16 and the cooling water discharge chamber 17 are communicated with each other, and are shut off when closed. The water channel 5 and the water channel 8 are the cooling water introduction chamber 1
6 and the water channel 7 is connected to a cooling water discharge chamber 17. Reference numeral 22 denotes a spring for urging the valve body 21 upward in the figure.

In this circuit, the temperature of the cooling water whose temperature rises due to heat exchange in the water jacket of the cylinder block 3 of the engine 1 is kept at a constant value (eg, 88 ° C.).
The thermostat 18 is used so as not to open until the pressure reaches the limit. At this time, the cooling water flowing out of the water pump 4 of the engine 1 is sent to the heater unit 10 but not to the radiator 9. Therefore, the heater unit 10 functions, but the radiator 9 does not function.

Time has elapsed since the engine 1 was started,
When the cooling water temperature rises to a certain value, the thermostat 1
8 opens. Thus, the cooling water that has entered the cooling water introduction chamber 16 of the thermostat case 14 flows through the thermostat 18 whose valve has been opened, and also flows from the cooling water discharge chamber 17 to the radiator 9. As a result, heat is converted into an airflow passing through the radiator 9, and an efficient cooling operation is performed.

[0009]

As described above, in the cooling system of an automobile engine generally used conventionally,
Since the valve opening temperature of the thermostat 18 is adjusted only to the operating temperature of the radiator 9, if the set temperature is increased, the cooling water flows only to the heater unit 10 without going to the radiator 9 until the set temperature is reached. Although all the energy can be consumed and the performance of the heater unit 10 is improved, the cooling performance of the engine is reduced. On the other hand, when the set temperature is lowered, most of the cooling water is cooled by the radiator 9, so that the cooling efficiency is improved, but there is a problem that the heater performance is lowered.

Therefore, conventionally, the set temperature has been determined in consideration of both the cooling performance of the engine cooling water and the performance of the heater. In some cases, priority was given to the cooling performance of the engine cooling water. For this reason, the temperature is compromised, and it may be difficult to obtain sufficient heater performance when the capacity of the heater unit is large or when a plurality of heater units are used in a large vehicle or the like.

The present invention has been made in view of this point, and has a structure using two thermostats having different set temperatures in order to satisfy both the cooling performance of the engine cooling water and the performance of the heater. It is intended to provide. As a prior art, Japanese Utility Model Laid-Open No. 61-19473
There is one disclosed in Japanese Patent Application Laid-Open No. 1 (1994). This publication is also common with the present invention in that two thermostats having different set temperatures are used, but has a configuration in which a distribution valve is provided to use only one of them.
The present invention provides a structure that does not use a distribution valve.

[0012]

According to the present invention, as a means for solving the above-mentioned problems, according to the first aspect of the present invention, there is provided a thermostat case in which a valve opening temperature is made different. The two thermostats are housed separately from the cooling water introduction chamber, and a solenoid valve is interposed between the cooling water introduction chambers of the two thermostats so that the thermostat cooling water introduction chamber has a high valve opening temperature. A connection port for introducing engine cooling water and a connection port for a heater unit are provided.

According to the second aspect of the present invention, a thermostat case is provided in which the interior is divided into first and second cooling water introduction chambers and one cooling water discharge chamber, and the first cooling water introduction chamber is provided. A first thermostat that opens at a high temperature between the second cooling water introduction chamber and the cooling water discharge chamber, and a second thermostat that opens at a low temperature between the second cooling water introduction chamber and the cooling water discharge chamber. A thermostat is interposed between the first and second cooling water introduction chambers, and an electromagnetic valve which is controlled by a heater switch to conduct and shut off is interposed. A connection port for introducing water and a connection port for a heater unit are provided, and a connection port for a radiator is provided in the cooling water discharge chamber.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
Will be described. What is shown is a thermostat device 23 according to the present invention, which is used in place of the one shown by reference numeral 6 in FIG. 6, but for convenience, the same members are described with different reference numerals. In the thermostat device 23, the inside of the thermostat case 24 is partitioned into first cooling water introduction chamber 27, second cooling water introduction chamber 28, and one cooling water discharge chamber 29 by partition walls 25 and 26. .

Inside the thermostat case 24, the first
A first thermostat 30, which opens at a high temperature, is interposed between the cooling water introduction chamber 27 and the cooling water discharge chamber 29. The second cooling water introduction chamber 28 and the cooling water discharge chamber 2
Between 9, a second thermostat 31 which opens at a low temperature is interposed. An electromagnetic valve 33 controlled by a heater switch 32 for conducting and shutting off is interposed between the first and second cooling water introduction chambers 27 and 28. In addition,
The solenoid valve 33 is of a type that is closed when the heater switch 32 is closed.

The structure of the first and second thermostats 30 and 31 is not different from the thermostat 18 in FIG. That is, when the thermowax 34 expands, the valve body 36 moves via the rod 35 which moves downward in the figure, and a gap is formed between the thermowax 34 and the partition wall 26, the first cooling water introduction chamber 27 and the cooling water discharge The chamber 28 is connected so that it is closed when contracted and closed. A spring 37 biases the valve body 36 upward in the figure. To make the valve opening temperatures of the first and second thermostats 30 and 31 different, the balance point between the thermowax 34 and the spring 37 may be changed.

The thermostat device 23 having this structure includes:
Connection ports 38 and 39 are provided in the first cooling water introduction chamber 27, and a connection port 40 is provided in the cooling water discharge chamber 28. The connection port 38 is connected to the water channel 5 in FIG.
The connection port 39 is connected to the water channel 8 in FIG. Further, the connection port 40 is used by connecting to the water channel 7 in FIG. Parts other than the thermostat device 23 are exactly the same as those in FIG.

The operation will be described with reference to FIGS.
Assuming that the operating temperature of the first thermostat 30 that opens at a high temperature is 88 ° C. and the operating temperature of the second thermostat 31 that opens at a low temperature is 70 ° C., the cooling water temperature becomes 70 ° C. immediately after the start of the engine. Until the first and second thermostats 30 and 31 are both opened (the state of FIG. 1). At this time, if the heater switch 32 is not closed, the electromagnetic valve 33 is also opened, so that the first and second cooling water introduction chambers 27 and 28 are in communication.

At this time, the cooling water that has entered the first cooling water introduction chamber 27 from the connection port 38 flows through the connection port 39 to the heater unit (see FIG. 6). Does not work.

When the temperature of the cooling water rises after a certain period of time from the start of the engine, first, the second thermostat 31 which opens at 70 ° C. opens, and then the first thermostat 31 which operates at 88 ° C. 30 opens. At this time, when the heater switch 32 is closed to use the heater, the solenoid valve 33 is closed, so that the first and second cooling water introduction chambers 27 and 28 are shut off, and the cooling water is supplied to the second cooling water introduction chamber 28. Never spin.

As shown in FIG. 2, the cooling water is supplied to the first opened valve.
Flows through the thermostat 30 from the connection port 39 to the heater unit, and from the connection port 40 of the cooling water discharge chamber 29 toward the radiator. At this time, since the cooling water temperature is as high as 88 ° C. or higher, the heater unit also functions sufficiently.

The state shown in FIG. 3 is when the temperature of the cooling water of the engine exceeds 70 ° C. and does not reach 88 ° C., and the heater is not used. At this time, the cooling water from the engine goes to the heater unit, but since the cooling water temperature is within the above range, the first thermostat 30 that opens at a high temperature does not open and the first cooling water is introduced. The cooling water that has entered the chamber 27 does not flow to the cooling water discharge chamber 29 via the first thermostat 30.

Since the heater is not used, the heater switch 32 is opened, and the solenoid valve 33 is opened, so that the cooling water entering the first cooling water introduction chamber 27 from the connection port 38 passes through the solenoid valve 33. And the second cooling water introduction chamber 28
to go into. Since the second thermostat 31 is open, the cooling water passes through it and enters the cooling water discharge chamber 29, and flows from the connection port 40 to the radiator.

FIG. 4 shows the relationship between the temperature of the engine cooling water and the elapsed time from the start of the engine. It can be seen from this figure that the control at 88 ° C.
The time to reach the same temperature is slightly shorter than when controlled at ° C. For this reason, as shown in FIG. 2, when the heater switch 32 is closed to use the heater unit, the temperature of the engine cooling water becomes high within a short period of time from the start of the engine, so that the heater performance is improved.

FIG. 5 shows the relationship between the engine output and the engine speed. From this figure, it can be seen that the temperature of the engine cooling water is 7 times higher than when controlling at 88 ° C.
Controlling at 0 ° C. means that the output is higher at the same rotational speed. This is because the cooling performance of the engine is improved, the knocking limit is improved, and a high output is obtained over the entire engine speed range, so that it is possible to cope with heat damage in summer.

[0026]

The present invention relates to a cooling water temperature control device for an engine configured as described above, which uses two thermostats having different valve opening temperatures and is provided upstream of the thermostat having a low operating temperature. A solenoid valve controlled by a heater switch is interposed, and this solenoid valve is controlled to be turned on and off by a heater switch.If the solenoid valve is closed, the high-temperature cooling water from the engine remains as it is. It is sent to the heater unit and can improve the heater performance. When the solenoid valve is open because the heater is not used, the cooling water flows to the radiator through the thermostat that opens at a low temperature, thereby improving the cooling efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which a solenoid valve is closed and one thermostat is opened in FIG.

FIG. 3 is a schematic diagram showing a state in which the solenoid valve is opened and the other thermostat is opened in FIG.

FIG. 4 is a graph showing the relationship between the temperature of engine cooling water and the time elapsed since the start of the engine.

FIG. 5 is a graph showing a relationship between an engine output and an engine speed.

FIG. 6 is a system diagram partially showing a schematic perspective view of a cooling system of an automobile engine generally used conventionally.

[Explanation of symbols]

 Reference Signs List 1 engine 9 radiator 10 heater unit 23 thermostat device 24 thermostat case 25 partition wall 26 partition wall 27 first cooling water introduction chamber 28 second cooling water introduction chamber 29 cooling water discharge chamber 30 first thermostat 31 second thermostat 32 Heater switch 33 Solenoid valve 38 Connection port 39 Connection port 40 Connection port

Claims (2)

[Claims] 1. Inside a single thermostat case,
Two thermostats having different valve opening temperatures are housed separately from the cooling water introduction chamber, and an electromagnetic valve is interposed between the cooling water introduction chambers of the two thermostats to reduce the valve opening temperature. A cooling water temperature control device for an engine, wherein a connection port for introducing engine cooling water and a connection port for a heater unit are provided in a cooling water introduction chamber of a high thermostat. 2. A thermostat case having an interior partitioned into first and second cooling water introduction chambers and one cooling water discharge chamber, and a thermostat case is provided between the first cooling water introduction chamber and the cooling water discharge chamber. A first thermostat that opens at a temperature is interposed, and a second thermostat that opens at a low temperature is interposed between a second cooling water introduction chamber and a cooling water discharge chamber. An electromagnetic valve controlled and controlled by a heater switch to conduct and shut off between the two cooling water introduction chambers; a connection port for introducing cooling water for the engine into the first cooling water introduction chamber; and a heater unit. A cooling water temperature control device for an engine, wherein a connection port to a radiator is provided in a cooling water discharge chamber, and a connection port to a radiator is provided in the cooling water discharge chamber.