JP2000274245A - Cooling water flow temperature controller for engine water cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an engine start permissible lower limit temperature below an inflow start lower limit temperature to a cylinder jacket. SOLUTION: In this controller, a bypass completion temperature T2, at which a bypass valve 10 opens is set to a higher temperature than a warm-up completion set temperature T1 at which a thermostat 8 opens. In a warm-up completion transient state since the temperature of cooling water flowing out of a head jacket 3 exceeds the warm-up completion set temperature T1 until the temperature of the cooling water reaches the bypass completion temperature T2 at which the bypass valve 10 opens, both the thermostat 8 and the bypass valve 10 open, so that the cooling water is fed to a cylinder jacket 2. After increasing a temperature of the low-temperature cooling water flowed from a radiator 5 through a cooling water channel 6 on the suction side of a cooling water pump 7 by the mixing of the high-temperature cooling water flowed from the head jacket 3 through a bypass 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for controlling the flow of cooling water of an engine water cooling system between a radiator and a bypass.
The present invention relates to a device for controlling the temperature of cooling water.

[0002]

[Premise Configuration] The cooling water flow temperature control device of the engine water cooling system according to the present invention is, for example, shown in FIGS.
As shown in FIG. 1 (prior art), the object having the following premise configuration is targeted.

[Premise Configuration] FIG. 4 is a vertical sectional side view of a water cooling system of an engine, and FIGS. 1-3 and 6 are vertical sectional side views of a thermostat bypass valve portion in FIG. Replace the cylinder jacket (2) of the water-cooled engine (1) with the head jacket
(3) ・ Water channel (4) ・ Radiator (5) ・ Cold channel (6) ・ Cooling water pump (7)
(2) is circulated. A thermostat (8) is provided in one of the hot water channel (4) and the cold water channel (6), and the head jacket (3) is connected to the suction side of the cooling water pump (7) via the bypass (9). 9) A bypass valve (10) is provided.

When the temperature of the cooling water flowing out of the head jacket (3) is in a warm-up operation temperature range lower than the warm-up end set temperature (T1), the thermostat (8) is closed. In addition, the circulation of the cooling water to the radiator (5) is stopped, and the bypass valve (10) is opened to circulate the cooling water to the bypass (9). Head jacket
The temperature of the cooling water flowing out from (3) is the warm-up end set temperature.
When the temperature is higher than (T1) and the temperature is within the temperature range after the completion of the warm-up, the thermostat (8) opens to circulate the cooling water to the radiator (5), and closes the bypass valve (10). Thus, the circulation of the cooling water to the bypass (9) is stopped.

First, during warm-up operation after cold start of the engine (1), the head jacket
The temperature of the cooling water flowing out from (3) is the warm-up end set temperature (T
Since the temperature is lower than 1), the thermostat (8) closes and the temperature of the engine (1) rapidly rises as much as the cooling water is not cooled by the radiator (5). At the same time, the bypass valve (10) is opened, and the cooling water flows through the cylinder jacket (2) and the head jacket (3) by an amount corresponding to the flow rate of the cooling water passing through the bypass (9). Prevent local overheating of the cylinder head.

Next, the warm-up operation of the engine (1) is completed,
After the temperature of the cooling water flowing out of the head jacket (3) becomes higher than the set-up temperature (T1), the thermostat (10) opens and the cooling water is cooled through the radiator (5). To prevent overheating of the engine (1). At this time, the amount of cooling water passing through the radiator (5) is increased by the amount by which the bypass valve (10) is closed and a part of the cooling water is not short-circuited from the bypass (9). Radiator (5)
Can be reduced in size.

[0007]

2. Description of the Related Art In the above premise, the bypass valve (10)
FIG. 6 shows a configuration in the related art for operating the. FIG. 6 is a vertical sectional side view of a thermostat bypass valve portion of a water cooling device for an engine according to the prior art.

[0008] The bypass valve (10) comprises a bypass valve body (81) and a bypass valve seat (82). The bypass valve (81) is fixed to the lower end of the wax case (83) of the wax-type thermostat (8). The bypass valve seat (82) is
It is formed on the peripheral wall of the inlet (12) of the bypass (9) below 1). As a result, during warm-up operation of the engine (1),
Until the temperature of the cooling water flowing out of the head jacket (3) rises to the set temperature (T1) for opening the thermostat (8), the bypass valve (10) is opened and the thermostat (8) is closed. I do. The temperature of the cooling water is thermostat
When the temperature rises to the set valve opening temperature (T1) of (8), the thermostat (8) opens and the bypass valve (10) closes.

[0009]

The above prior art has the following problems. (I). The engine start allowable lower limit temperature (TD) cannot be reduced below the lower limit temperature (Ta) at which low-temperature cooling water in the radiator (5) starts flowing into the cylinder jacket (2).

At the end of warm-up of the engine, the thermostat
Immediately after the valve (8) is opened and the low-temperature cooling water in the radiator (5) starts flowing into the cylinder jacket (2), the cylinder is rapidly cooled by the low-temperature cooling water, causing thermal distortion. If the thermal strain exceeds the allowable value, the piston may seize to the cylinder. In order to prevent the seizure of the piston, it is necessary to limit the temperature of the low-temperature cooling water that starts flowing into the cylinder jacket (2) so as not to fall below a predetermined inflow start lower limit temperature (Ta). This inflow start lower limit temperature
(Ta), the allowable lower limit temperature (TD) for starting the engine.
Is decided.

First, during a warm-up operation after a cold start of the engine (1), the thermostat (8) closes, cooling water does not circulate through the radiator (5), and the bypass valve (10) opens. The cooling water is circulating in the bypass (9).

Next, the warm-up operation proceeds, and the head jacket
The temperature of the cooling water flowing out from (3) is the warm-up end set temperature (T
When the temperature rises to 1), the thermostat (8) opens and low-temperature cooling water at the initial temperature (Tb) in the radiator (5) starts flowing from the cooling water pump (7) into the cylinder jacket (2). . At the same time, the bypass valve (10) closes and the high-temperature cooling water flowing out of the cylinder jacket (3) stops flowing to the bypass (9). Because of this, the radiator
The low-temperature cooling water of the initial temperature (Tb) in (5) flows into the cylinder jacket (2) at that temperature.

Thus, the allowable lower limit temperature for starting the engine is obtained.
(TD) becomes the same temperature as the lower limit temperature (Ta) at which the inflow to the cylinder jacket (2) starts.
It cannot be reduced below (Ta).

An object of the present invention is as follows. (I). The engine start allowable lower limit temperature (TD) is set to be lower than the lower limit temperature (Ta) at which inflow into the cylinder jacket starts. (B). A manufacturing cost of a bypass valve as a configuration for achieving the above object (a) can be reduced.

[0015]

According to the present invention, there is provided a cooling water flow temperature control device for a water cooling system for an engine according to the present invention, in which the bypass valve (10) is operated to solve the above-mentioned problems. The following feature configuration is added.

○ Invention 1. Claim 1. FIG. 1 and FIG. 5 are longitudinal sectional side views of a thermostat bypass valve portion showing an embodiment of a cooling water flow temperature control device of a water cooling device for an engine according to the present invention. 3 shows the state of the transition period. FIG. 1 shows the first embodiment.
FIG. 5 shows a second embodiment.

As illustrated in FIG. 1 or FIG. 5, the bypass end temperature (T) at which the bypass valve (10) closes is lower than the warm-up end temperature (T1) at which the thermostat (8) opens.
Set 2) to high temperature.

After the temperature of the cooling water flowing out of the head jacket (3) exceeds the set temperature (T1) for opening the thermostat (8), the temperature reaches the end temperature (T2) at which the bypass valve (10) closes. During the warm-up end transition state in which the temperature of the cooling water discharged from the head jacket (3) is within the simultaneous valve opening temperature range before reaching, both the thermostat (8) and the bypass valve (10) are turned off. Both valves are opened, and on the suction side of the cooling water pump (7), low-temperature cooling water flowing from the radiator (5) through the cooling water passage (6) is bypassed from the head jacket (3).
The temperature is raised by mixing the high-temperature cooling water flowing through (9), and then the pressure is fed to the cylinder jacket (2) by the cooling water pump (7).

○ Invention 2. Claim 2. See FIG. 1 As exemplified in FIG. 1, the valve body (11) of the bypass valve (10)
Is made of a temperature-sensitive operating material such as a bimetal or a shape memory alloy. A bypass valve seat (14) and a bypass valve body support (15) are formed on the peripheral wall surface (13) of the inlet (12) of the bypass (9). A valve body (11) made of a temperature-sensitive operating material is attached to the bypass valve body support (15).
Is supported.

[0020]

The function and effect of the present invention are as follows. ○ Invention 1. Claim 1. See FIG. 1 to FIG. 4 or FIG. 5 (a). The engine start allowable lower limit temperature (TD) is increased by the temperature rise (tc) caused by the bypass flow to the cylinder jacket.
(2) The temperature is lower than the lower limit temperature (Ta) at which inflow to the flow starts.

FIG. 4 shows a water cooling system for the engine. FIGS. 1 and 5 are longitudinal side views of a thermostat bypass valve portion showing an embodiment of a cooling water flow temperature control device of a water cooling device for an engine according to the present invention. Show. FIG. 1 shows the first embodiment, and FIG. 5 shows the second embodiment.

At the end of warm-up of the engine, the thermostat
Immediately after the valve (7) is opened and the low-temperature cooling water in the radiator (5) starts flowing into the cylinder jacket (2), the low-temperature cooling water rapidly cools the cylinder (21) and causes thermal distortion. If the amount of thermal strain exceeds an allowable value, the piston (22) may seize to the cylinder (21). In order to prevent the seizure of the piston (22), it is necessary to limit the temperature of the low-temperature cooling water that starts flowing into the cylinder jacket (2) so as not to fall below a predetermined inflow start lower limit temperature (Ta). Based on the inflow start lower limit temperature (Ta), the engine start allowable lower limit temperature (TD) is determined.

First, during the warm-up operation after the cold start of the engine (1), as shown in FIG. 2, the thermostat (8) closes and the cooling water does not circulate through the radiator (5). The bypass valve (10) is opened, and the cooling water is circulating in the bypass (9).

Next, the warm-up operation proceeds, and the head jacket
The temperature of the cooling water flowing out from (3) is the warm-up end set temperature (T
When the temperature rises to 1), the thermostat (8) is opened to reach the state illustrated in FIG. 1, and the low-temperature cooling water at the initial temperature (Tb) in the radiator (5) is supplied from the cooling water pump (7). It begins to flow into the cylinder jacket (2).

At the same time, during the period from the time when the temperature of the cooling water discharged from the head jacket (3) rises to the warm-up end temperature (T1) to the time when it exceeds the bypass end temperature (T2), , The bypass valve (10) continues to open. Therefore, a part of the high-temperature cooling water flowing out of the head jacket (3) flows from the bypass (9) to the suction side of the cooling water pump (7), where the low-temperature cooling water flows from the radiator (5). After mixing, the temperature of the low-temperature cooling water is raised from the initial temperature (Tb) in the radiator by (tc), and then starts flowing into the cylinder jacket (2).

Then, the head is cooled within a period from the time when the temperature of the cooling water flowing out of the head jacket (3) rises to the warm-up end set temperature (T1) to the time when the temperature exceeds the bypass end temperature (T2). The high-temperature cooling water coming out of the jacket (3) fills the radiator (5).

Thereafter, the temperature of the cooling water flowing out of the head jacket (3) rises to the bypass end temperature (T2), and the bypass valve (10) closes as illustrated in FIG. Cooling water does not flow to the bypass (9).

In the above operation, as shown in FIG. 1, the temperature of the cooling water coming out of the head jacket (3) rises to the warm-up ending set temperature (T1), and the bypass ending temperature (T2 ), The bypass valve (10) continues to open and the head jacket
Part of the high-temperature cooling water flowing out from (3) flows into the suction side of the cooling water pump (7) from the bypass (9), and the temperature of the low-temperature cooling water flowing from the radiator (5) is initialized in the radiator. After the temperature (Tb) is increased by (tc) from the temperature (Tb), the cooling water whose temperature has increased starts flowing into the cylinder jacket (2).

As a result, the allowable lower limit temperature for starting the engine is obtained.
(TD) indicates that the low-temperature cooling water from the radiator (5) is bypassed.
The lower temperature (Ta) at which inflow into the cylinder jacket (2) can be reduced by the amount (tc) of the temperature rise by the high-temperature cooling water from (9).

○ Invention 2. Claim 2. See Fig. 1 (b). The manufacturing cost of the bypass valve (10) can be reduced. The bypass valve (10) includes a valve body (11) made of a temperature-sensitive operating material such as a bimetal or a shape memory alloy, and a bypass valve seat (14) formed on an inlet peripheral wall surface (13) of the bypass (9). Since a simple configuration consisting of the valve body support portion (15) is sufficient, compared with a case where the configuration is similar to that of the wax type thermostat,
The manufacturing cost can be reduced.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling water flow temperature control device for a water cooling device for an engine according to the present invention will be described below with reference to the drawings.

Embodiment 1 Claims 1.2. FIG.
-See FIG. 4 FIG. 4 is a vertical side view of the water cooling device of the engine. Figure 1
FIG. 3 is a vertical sectional side view of a thermostat bypass valve. FIG.
3 shows a state during the engine warm-up operation, and FIG. 3 shows a state after the engine warm-up is completed.

As shown in FIG. 4, a cylinder jacket (2) of a water-cooled vertical in-line four-cylinder diesel engine (1) is connected to a head jacket (3), a hot water channel (4), a radiator (5), and a cold water channel (6). And in order through the cooling water pump (7) and the cylinder jacket (2) in a circulating manner.

A wax type thermostat (8) is provided at the inlet of the hot water channel (4). As shown in FIG. 1, the wax-type thermostat (8) uses a volume expansion when a wax (29) in a wax case (23) changes from a solid to a liquid, thereby forming a valve body (24). Valve seat (26) against valve closing spring (25)
And the valve is opened. Cooling water pump (7) through bypass (9) through head jacket (3)
To the suction side of A bypass valve (10) is provided at the entrance of the bypass (9).

When the temperature of the cooling water flowing out of the head jacket (3) is in a warming-up operating temperature range lower than the warming-up end set temperature (T1), as shown in FIG. 8) is closed to stop the circulation of the cooling water to the radiator (5), and the bypass valve (10) is opened to circulate the cooling water to the bypass (9). In a state in which the temperature of the cooling water flowing out of the head jacket (3) is within the post-warming-up temperature range that is higher than the warm-up ending set temperature (T1), as shown in FIG. The valve is opened to circulate the cooling water to the radiator (5), and the bypass valve (10) is closed to stop the circulation of the cooling water to the bypass (9).

The bypass end temperature (T2) at which the bypass valve (10) closes is set higher than the warm-up end temperature (T1) at which the thermostat (8) opens. Head jacket
The temperature of the cooling water flowing out of (3) is the thermostat (8)
From the head jacket (3) within the simultaneous valve opening temperature range from exceeding the valve opening set temperature (T1) to reaching the bypass end temperature (T2) at which the bypass valve (10) closes. As shown in FIG. 1, in the state of the transition to the end of warm-up in which the temperature of the cooling water is contained, the thermostat (8) and the bypass valve (10)
Are both opened, and on the suction side of the cooling water pump (7), the low-temperature cooling water flowing from the radiator (5) through the cooling water passage (6) passes through the bypass (9) from the head jacket (3). ), The temperature is raised by mixing high-temperature cooling water flowing through the cooling water pump (7), and then the pressure is sent to the cylinder jacket (2) by the cooling water pump (7).

Then, the temperature of the cooling water discharged from the head jacket (3) rises to the warm-up end set temperature (T1) and exceeds the bypass end temperature (T2). The radiator (5) is configured to be filled with high-temperature cooling water coming out of the jacket (3).

The valve body (11) of the bypass valve (10) is made of a temperature-sensitive operating material such as bimetal or shape memory alloy.
A bypass valve seat (1) is provided on the peripheral wall (13) of the inlet (12) of the bypass (9).
4) and the bypass valve body support (15) are formed. A valve body (11) made of a temperature-sensitive operating material is bolted to the bypass valve body support (15).
This is fixed and configured in (16). In FIG. 4, reference numeral (21) denotes a cylinder, (22) denotes a piston, (27) denotes a crankshaft, and (28) denotes a radiator fan.

Embodiment 2 Claim 2 See FIG. 5 A part of the configuration of the first embodiment is changed as follows. The bypass valve (10) is changed from a structure using the bypass valve body (10) made of a temperature-sensitive operating material shown in FIG. 1 to a wax type shown in FIG. The wax type bypass valve (10) has the same structure as the wax type thermostat (8).

Embodiment 3 Claims 1.2. The illustration is omitted. In the configuration of the first embodiment, a part thereof is changed as follows. The position where the thermostat (8) is provided is moved from the inlet of the hot water channel (4) shown in FIG.
Change to the exit of (6).

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a thermostat bypass valve portion showing a first embodiment of a cooling water flow temperature control device for a water cooling device for an engine according to the present invention, and shows a state of a transition period of the end of engine warm-up.

FIG. 2 is a vertical side view of the same thermostat bypass valve as FIG. 1, showing a state during an engine warm-up operation.

FIG. 3 is a longitudinal side view of the same thermostat bypass valve portion as in FIG. 1, showing a state after engine warm-up is completed.

FIG. 4 is a vertical sectional side view of a water cooling device of the engine.

FIG. 5 shows a thermostat according to a second embodiment of the present invention.
It is a vertical side view of a bypass valve part, and shows the state of the transition period of engine warm-up completion.

FIG. 6 is a vertical sectional side view of a thermostat bypass valve portion of a water cooling device for an engine according to the related art.

[Explanation of symbols]

1: Water-cooled engine. 2. Cylinder jacket. 3 ...
Head jacket. 4: Hot water channel. 5. Radiator.
6. Cold water channel. 7 ... Cooling water pump. 8. Thermostat. 9 ... Bypass. 10. Bypass valve. 11. Bypass valve body. 12 ... Bypass entrance. 13: Entrance peripheral wall. 14 ... Bypass valve seat. 15 ... Bypass valve body support. T1: Warm-up end set temperature. T2: Bypass end temperature.

Claims (2)

[Claims] Cylinder jacket of a water-cooled engine (1)
(2) is circulated to the cylinder jacket (2) through the head jacket (3), the hot water channel (4), the radiator (5), the cold water channel (6), and the cooling water pump (7) in this order. Thermostat in either hot water channel (4) or cold water channel (6)
(8), the head jacket (3) is connected to the suction side of the cooling water pump (7) via the bypass (9), and the bypass (9)
A bypass valve (10) is provided in the head jacket (3). When the temperature of the cooling water flowing out of the head jacket (3) is in a warm-up operation temperature range lower than the warm-up end set temperature (T1), the thermostat (8) is used. ) Is closed to stop the circulation of the cooling water to the radiator (5), and the bypass valve (10) is opened to circulate the cooling water to the bypass (9). In a state where the temperature of the cooling water flowing out of (3) is within the temperature range after the completion of warm-up, which is higher than the warm-up end set temperature (T1), the thermostat (8) opens and the radiator cools the cooling water. In the cooling water flow temperature control device of the water cooling device for the engine, the thermostat is configured to circulate the cooling water to the bypass (9) while closing the bypass valve (10) while circulating the cooling water to the bypass (9). (8) Warm-up end set temperature at which valve opens (T1)
Than the bypass end temperature at which the bypass valve (10) closes
(T2) is set to a high temperature. After the temperature of the cooling water flowing out of the head jacket (3) exceeds the valve opening set temperature (T1) of the thermostat (8),
The warm-up end transient state in which the temperature of the cooling water discharged from the head jacket (3) is within the simultaneous valve opening temperature range until the bypass end temperature (T2) at which the bypass valve (10) closes. Then, both the thermostat (8) and the bypass valve (10) are opened, and on the suction side of the cooling water pump (7), the low-temperature cooling air flowing from the radiator (5) through the cold water passage (6) The temperature of the water is raised by mixing high-temperature cooling water flowing from the head jacket (3) via the bypass (9), and then the water is pumped to the cylinder jacket (2) by the cooling water pump (7). A cooling water flow temperature control device for an engine water cooling device, comprising: 2. The valve body (11) of the bypass valve (10) is made of a temperature-sensitive operating material, and a bypass valve seat (14) and a bypass valve are provided on a peripheral wall surface (13) of an inlet (12) of the bypass (9). 2. A valve body made of a temperature-sensitive actuating material, said body being formed with a body support portion, said bypass valve body support portion being supported by said bypass valve body support portion. Cooling water temperature control device for water cooling system of engine.