JP2737611B2 - 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 engine cooling device,
In particular, the present invention relates to a cooling device for a water-cooled engine provided with a radiator.

[0002]

2. Description of the Related Art When an engine is driven, it is heated by the heat generated by the combustion of fuel. In this case, each drive unit in the engine is set so as to be able to drive properly after a predetermined thermal expansion has occurred, and enters an appropriate drive state when the engine warm-up is completed. However, excessive heating of the engine causes uneven wear and deformation of each part of the engine, and reduces the durability of the engine. As a result, a water jacket for circulating cooling water is formed in the engine body, and the cooling water in the water jacket is formed. Is circulated to a radiator outside the engine body, and the heat generated by the engine is successively radiated to the outside air to keep the engine in a warm-up completed state at a predetermined temperature or lower. By the way, in such a water-cooling type cooling device using cooling water, the upper part of the water jacket of the engine body communicates with the upper tank of the radiator, and the water pump communicating with the water jacket communicates with the lower tank of the radiator.

[0003] When the engine is driven, a water pump is constantly driven, relatively high-temperature cooling water in the upper portion of the water jacket is introduced into the upper tank, and low-temperature cooling water cooled by the radiator is supplied from the lower tank to the water jacket via the water pump. The cooling water is again configured to circulate in the water jacket. By the way, circulating the cooling water when the engine is cold causes a delay in warming-up of the engine.Therefore, usually, the engine is provided with a wax-type thermostat near the communication port of the radiator with the upper tank, and the radiator is heated until the temperature of the thermostat exceeds a predetermined temperature. The introduction of cooling water to the

[0004]

By the way, it is assumed that the warm-up progresses when the engine is cold, and the thermostat opens soon. In this case, the radiator is filled with low-temperature cooling water, which flows into the water jacket at once by a water pump. Then, the temperature of the engine body, which has just been warmed up, is lowered at a stretch, resulting in an insufficient warming-up state. As a result, the temperature of the drive unit in the engine body drops again, the lubricating oil flow in the sliding unit tends to decrease, and uneven wear parts easily occur, so-called cooling shocks occur. Moreover, once the thermostat is opened and cold water is introduced into the water jacket, the cooling system may repeat a hunting phenomenon in which the thermostat closes again due to a decrease in engine temperature and then opens again. When the engine is started, the cooling shock is likely to occur. SUMMARY OF THE INVENTION An object of the present invention is to provide an engine cooling device that can prevent a decrease in engine durability due to a sudden change in a cooling temperature of a cooling system at the time of engine start.

[0005]

In order to achieve the above object, the present invention provides a cooling water outflow passage for sending cooling water from an engine to a radiator, and a cooling water inflow passage for sending the cooling water from the radiator to the engine. A bypass valve connecting the cooling water outflow passage and the cooling water inflow passage, a first valve provided between the branch of the bypass passage in the cooling water outflow passage and the radiator, and a bypass valve provided in the bypass passage. a second valve which was a control for controlling the temperature sensor is provided et the above engine near the cooling water inlet passage, the opening and closing of the cooling water temperature detected by the temperature sensor and the first valve the second valve Cooling device having means
The control means may control the cooling water temperature to a first setting.
If it is lower than the value, the first valve is closed and the second valve is opened,
When the value is higher than the first set value and lower than the second set value
Opens both the first valve and the second valve and sets the second setting
If it is higher than the value, open the first valve and close the second valve
It is characterized in that it is controlled to be in a state . The cooling device for an engine according to claim 1, wherein a mixing space may be provided at a junction of the bypass passage and the cooling water inflow passage. In the engine cooling device according to claims 1 and 2, the first valve and the second valve may be electromagnetic valves.

[0006]

According to the present invention, the temperature of the cooling water detected by the temperature sensor provided near the engine in the cooling water inflow passage is equal to the first temperature .
If it is lower than the set value, the first valve is closed and the second valve is closed.
Open, thereby bypassing the cooling water from the cooling water outflow passage
Return to the water jacket via the passage and cooling water inflow passage
And a value higher than the first set value and lower than the second set value.
In this case, both the first valve and the second valve are opened,
After passing the cooling water through the cooling water outflow passage,
And then separate them and cool them again.
Return to the water jacket through the recirculating water inflow passage,
If it is higher than the set value, the first valve is opened and the second valve is opened.
To the closed state, which allows the cooling water to flow through the cooling water
Water through the radiator and cooling water inflow passage
Return to the jacket, so when the engine warms up,
Increasing the temperature of the cooling water introduced into the tar jacket
I can do it. In one aspect of the invention, particularly, if a mixing space is provided at the junction of the bypass passage and the cooling water inflow passage, the mixing of the cooling water having different temperatures can be performed well. In one aspect of the invention, the same operation as in the first aspect of the invention can be obtained even when the first valve and the second valve are electromagnetic valves.

[0007]

FIG. 1 shows an engine cooling device according to an embodiment of the present invention. This device is a gasoline engine mounted on a vehicle (not shown) (hereinafter simply referred to as engine 1).
Will be equipped with A water jacket 2 covering the periphery of each cylinder is formed in the engine body 101, and an upper outlet 3 is provided at one end of an upper portion of the water jacket 2.
A lower inlet 4 is formed at one end of the lower part. A water pump 7 that rotates by receiving rotation of a crankshaft (not shown) is provided at a position outside the lower inlet 4 of the engine body 101. The inlet 701 of the water pump is connected to a lower pipe 8 that forms a cooling water inflow passage r2. Be linked. A water temperature sensor 9 for outputting a cooling water temperature signal T1 is provided near the inflow port 701 of the lower pipe 8, and the output is input to the engine control unit 6.

On the other hand, the upper outlet 3 of the engine body 101
The upper pipe 11 and the lower pipe 8 are connected to an upper tank 121 and a lower tank 122 of a radiator 12 which are provided to face the engine body 101, respectively. Moreover,
A branch portion 201 is formed at a position inside the upper outlet 3 of the engine body 101, and the branch portion 201 and the mixer 13 formed in the middle of the lower pipe 8 are connected by a bypass pipe 14 forming a bypass passage r3. You. The mixer 13 forms a mixing space for mixing both cooling water from the bypass pipe 14 and the lower tank 122 of the radiator, and has a volume sufficient to stir the cooling water from both paths. It can be supplied to the water pump 7 side. The first solenoid valve 1 that normally closes the outflow passage r1 at a position near the upper outlet 3 in the upper pipe 11
5, a second solenoid valve 16 that normally opens the bypass passage r3 near the connection position of the bypass pipe 14 and the mixer 13
Are provided, and both solenoid valves 15 and 16 are connected to the engine control unit 6 via a drive circuit (not shown),
Both valves are controlled to open and close according to the drive output of the engine control unit 6. Both of the solenoid valves 15 and 16 have a well-known configuration in which the flow path can be opened and closed by bringing a valve element driven by a solenoid into and out of contact with an annular valve seat provided in a cross-sectional direction of the flow path.

The engine control unit 6 is a main part of a microcomputer, and its input port is connected to a water temperature sensor 9 and its output port is connected to first and second solenoid valves 15 and 16 via a drive circuit (not shown). Is done.
A ROM (not shown) of the engine control unit 6 stores a cooling water control routine as shown in FIG. Here, the engine control unit 6 serves as a control means and controls the cooling water temperature T detected by the temperature sensor 9.
1 functions to control the opening and closing of the first and second solenoid valves 15 and 16. Here, especially when the cooling water temperature T1 is lower than the first set value T _B −1, the first solenoid valve 15
Is closed, the second solenoid valve 16 is opened, and the first set value T _B -1 is set.
Is lower than the (warm-up determination temperature T _B from being set as a temperature lower by a predetermined value) higher than the second set value T _B +1 (set as a temperature higher by a predetermined value than the warm-up determination temperature T _B) Opens both the first and second solenoid valves 15 and 16,
It is higher than the second set value T _B +1, the first solenoid valve 1
5 is opened and the second solenoid valve 16 is controlled to a closed state.

Hereinafter, the present invention will be described with reference to a cooling water control routine shown in FIG. When an engine key (not shown) is turned on, the engine control unit 6 executes a control process of a well-known main routine, and executes a cooling water control routine of FIG. In this case, first, when the process reaches step s1, the cooling water temperature T1 is taken. In step s2, it is determined whether or not the cooling water temperature T1 is higher than a first set value T _B -1. If it is lower (for example, time t1 in FIG. 3), the first solenoid valve 15 is turned off, that is, closed, and the second electromagnetic valve 15 is closed. The valve 16 is turned off, that is, opened, and the process returns to the main routine. As a result, the cooling water passes through the Wc route flowing into the water pump 7 through only the bypass path r3 in the bypass pipe 14, and the warming-up operation with suppressed heat radiation is promoted.

If it is determined in step s2 that the cooling water temperature T1 is higher than the first set value T _B -1 but lower than the second set value T _B +1 (for example, time t2 in FIG. 3), step s is performed.
4), the first solenoid valve 15 is turned on, that is, opened, and the second solenoid valve 16 is turned off, that is, opened, and the process returns. As a result, a part of the cooling water passes through the bypass passage r3 in the bypass pipe 14, and the other passes through the cooling water outflow passage r1 in the upper pipe 11, the radiator 12, and the cooling water inflow passage r2 of the lower pipe 8, and M where both cooling waters having a temperature difference are mixed at 13
Take the m route. As a result, a part of the cooling water in the radiator, which has been cooled at a point near the completion of warming-up, is sent to the water jacket 2 so as to raise the temperature of the cooling water in the radiator, and suddenly upon completion of the complete warming-up. This prevents low-temperature cooling water of the radiator from flowing into the water jacket and causing a cooling water shock to the engine body 101.

If it is determined in step s2 that the cooling water temperature T1 has exceeded the second set value T _B +1 and that the warm-up has been completed (FIG. 3).
For example, at time point t3), the process proceeds to step s5 where the first solenoid valve 15 is turned on, that is, opened, and the second solenoid valve 16 is turned on, that is, closed, and returns. In the initial stage of the switching, all the cooling water is formed by the cooling water outflow passage r1 in the upper pipe 11, the radiator 12, and the cooling water inflow passage r2 in the lower pipe 8.
_The radiator 12 which is relatively warm through the _H route
Of cooling water flows into the water jacket 2 at a stretch, but no cooling shock occurs, and the operation starts after normal warm-up is completed. As a result, prior to the completion of the warm-up, the cooling water of the radiator having a temperature difference in the mixer 13 and the high-temperature cooling water from the bypass path r3 are mixed in the mixer 13 in advance, and the cooling water of the radiator is gradually reduced. Even if all of the cooling water passes through the radiator 12 and flows into the water jacket 2 at the initial stage of switching after the completion of warm-up, the cooling shock and the hunting phenomenon of the cooling system are prevented, and the engine durability is improved. The drop can be prevented reliably.

[0013]

As described above, according to the present invention, the cooling water temperature detected by the temperature sensor is lower than the first set value.
Cooling water from the cooling water outflow passage to the bypass passage
Return to the water jacket via the water inflow passage,
If it is higher than the first set value and lower than the second set value,
After passing the cooling water through the cooling water outflow passage, the bypass passage and the water
-Divide into the jacket and merge them again and cool
Return to the water jacket through the water inflow passage,
If it is higher than the set value, the cooling water is
Water jacket through radiator and cooling water inflow passage
Return to water, when the engine warm-up is complete
The temperature of the cooling water introduced into the racket can be increased step by step.
You. Therefore, prior to the completion of warm-up of the engine,
High temperature cooling from radiator cooling water and bypass
Mix with water and gradually warm the radiator cooling water.
When the warm-up is completed, all the cooling water passes through the radiator
Even if it flows into the water jacket,
Hunting phenomenon of the cooling system can be prevented, and engine durability
Can be reliably prevented from decreasing. In particular, if a mixing space is provided at the junction of the bypass passage and the cooling water inflow passage, the cooling water with different temperatures can be mixed well, the cooling shock can be prevented, and the deterioration of the engine durability can be more reliably prevented. I can do it.
In particular, even if the first valve and the second valve are electromagnetic valves, the same effects as those of the first invention can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of an engine cooling device as one embodiment of the present invention.

FIG. 2 is a flowchart of a cooling water control routine performed by the cooling device of FIG. 1;

FIG. 3 is a switching timing chart of a first solenoid valve and a second solenoid valve in the cooling device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Water jacket 201 Branch part 6 Engine control unit 9 Temperature sensor r1 Cooling water outflow passage r2 Cooling water inflow passage r3 Bypass passageway 12 Radiator 13 Mixer 15 First solenoid valve 16 Second solenoid valve 16

Claims (3)

(57) [Claims] 1. A cooling water outflow passage for sending cooling water from an engine to a radiator, a cooling water inflow passage for sending the cooling water from the radiator to the engine, and a bypass connecting the cooling water outflow passage and the cooling water inflow passage. A passage, a first valve provided between the branch of the bypass passage in the cooling water outflow passage and the radiator, a second valve provided in the bypass passage, and the engine in the cooling water inflow passage has a temperature <br/> degree sensor et al are provided in the vicinity, and a control means for controlling the opening and closing of the first valve and the second valve by the cooling water temperature detected by the temperature sensor
In the cooling device for the engine, the control unit may be configured to control the first valve when the cooling water temperature is lower than a first set value.
Is closed and the second valve is opened. When the value is higher than the first set value and lower than the second set value,
Opens both the first valve and the second valve, and opens the first valve if the value is higher than the second set value.
And controlling the second valve to be in a closed state . 2. The engine cooling device according to claim 1, wherein a mixing space is provided at a junction of the bypass passage and the cooling water inflow passage. 3. An engine cooling device according to claim 1, wherein said first valve and said second valve are solenoid valves.