JPH032676Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an improvement of a cooling device for a water-cooled internal combustion engine.

(Prior art) As this type of cooling device, for example, one configured as shown in FIG.
(See Publication No. 140715).

The cooling water from the water pump 1 flows in this order through the oil cooler 2, the water jacket of the engine body 3 (cylinder block, cylinder head), and the radiator 5, returns to the water pump 1 suction port, and then flows through the oil cooler 2 and the engine body 3. The heat taken away during passing is radiated into the atmosphere by the radiator 5.

In this case, a plurality of thermostats 4 are installed at the water jacket outlet of the engine body 3, and these thermostats 4 control the cooling water from the engine body 3 without passing through the radiator 5 when the cooling water temperature is below a predetermined value. , and is returned to the water pump 1 via the bypass passage 8.

Reference numeral 9 denotes a water tank for storing cooling water, and the water tank 9 is communicated with the suction port side of the water pump 1 via a supply passage 13, and its interior is opened to atmospheric pressure via a cap 9a having a ventilation function. be done. 10 is Atsupa tank 5 of radiator 5
A and 11 are degassing passages which communicate passages 12 which cut off the water jackets of each cylinder outside the cylinder head with the inside of the water tank 9 (atmospheric pressure).

In addition, in order to improve the warm-up performance of such a cooling system, the cooling water in the engine water jacket is temporarily drained during warm-up operation by the present applicant, for example, in Utility Model Application No. −
It was proposed in No. 125204 (Utility Model Application No. 61-39426).

(Problem that the invention aims to solve) By the way, with such a cooling system, if you forget to replace the cooling water with antifreeze in winter, for example, the cooling water will freeze and the water jet of the engine body will be damaged. There was a problem that cracks and damage occurred in the butt, etc.

The purpose of this invention is to prevent cracks and damage caused by freezing of cooling water in the engine body.

(Means for solving the problem) Therefore, this invention provides a cooling system for a water-cooled internal combustion engine with an auxiliary tank whose surroundings are covered with a heat insulating material, and this auxiliary tank is placed in the center of the engine water jacket. It is connected to the water jacket via an extending insulated pipe.

(Function) After the engine is stopped, when the temperature of the cooling water in the water jacket falls below freezing, it gradually begins to freeze from near the inner surface of the jacket, and eventually the entire jacket freezes. During this freezing process, some of the cooling water Due to volumetric expansion due to freezing, it is pushed through the insulated pipe into the auxiliary tank. In other words, since the cooling water approximately corresponding to the volumetric expansion due to freezing escapes to the auxiliary tank, cracks and damage to the cylinder block and cylinder head are avoided.

(Example) In FIG. 1, 20 is the engine body, 21 is a water tank (the inside is opened to atmospheric pressure via a cap 21a having a ventilation function) disposed above the engine body 20, and 21 is a water tank disposed above the engine body 20. The surrounding area is covered with insulation material.

The water tank 21 is communicated with water jackets 23 and 24 of the engine body 20 via a pipe 22 covered with a heat insulating material.

In this case, the insulated pipe 22 is connected to the cylinder head 2.
A pipe portion 22a passes through the center of the water jacket 23 of the cylinder block 26 and further extends to the center of the water jacket 24 of the cylinder block 26.
and a pipe section 22b connected to the pipe section 22a at the upper part of the cylinder head 25 and communicating this to the space inside the water tank 21. Reference numeral 27 indicates holes formed on the outer periphery of the water jackets 23 and 24 of the pipe portion 22a, corresponding to the central portions thereof.

Note that in a multi-cylinder engine, the heat insulating pipe 22 is provided individually corresponding to each cylinder. Further, as the heat insulating material of the pipe portion 22a, a material that is not affected by cooling water, such as ceramics, may be used, and if necessary, a heater or the like may be incorporated inside the ceramic layer.

Therefore, when the cooling water temperature drops below freezing after the engine has stopped, the cooling water in the water jackets 23 and 24 will gradually start to freeze from near the inner surface of the jackets as shown in the figure, and eventually the whole will freeze. During the freezing process, some of the cooling water
Due to the volumetric expansion caused by freezing, the water is pushed out through the insulated pipe 22 into the water tank 21 .

On the other hand, when the ice in the water jackets 23 and 24 melts, for example, when the engine is started, the insufficient amount of cooling water in the water jackets 23 and 24 is drained to the water tank 2 via replenishment passages 37 and 38, which will be described later.
It is replenished from 1.

By the way, the cooling system of the engine main body 20 is constructed as shown in FIG.

31 is connected to the engine body 20 via an electromagnetic clutch 32.
33 is an oil cooler, 34 is a radiator, and the cooling water from the water pump 31 is connected to the oil cooler 33 and the water jacket 2 of the engine body 20, as before.
3, 24, and radiator 34, returns to the water pump 31 suction port, and then flows to the oil cooler 33.
The heat taken away when passing through the engine body 20 is radiated into the atmosphere by the radiator 34.

35 is a thermostat that returns the cooling water from the engine body 20 to the water pump 31 via the bypass passage 59 when the cooling water temperature is below a predetermined value;
5 and 56 indicate degassing passages, and the water tank 21
In this case, the supply passages 37 and 38 communicate with the upper tank 34a of the radiator 34 and the suction port side of the water pump 31, respectively.

Then, the water tank 21 and the supply passage 3
The entire cooling circuit 39 including the engine parts 7 and 38 except for the engine body 20 and the radiator 34 is covered with a heat insulating material.

A heat retention tank 40 is provided below the radiator 34 to drain the cooling water in the radiator 34 when there is a risk of freezing, and the heat retention tank 40 is connected to the water tank 21 via a passage 41.
communicated with the inside (atmospheric pressure).

The heat retention tank 40 is surrounded by a heat insulating material, and has a water drain passage 43 with a solenoid valve 42 interposed in the middle.
to the lower tank 34b of the radiator 34 via
In addition, a return passage 4 with an electric pump 44 interposed in the middle
5 to the water tank 21, respectively. Note that the water drain and return passages 43 and 45 are covered with a heat insulating material like the supply passages 37, 38, etc.

On the other hand, a solenoid valve 46 is located in the middle of the supply passage 37.
Further, a solenoid valve 48 is interposed in each cooling passage 47 connecting the lower tank 34b of the radiator 34 and the suction port of the water pump 31 (downstream of the confluence of the supply passage 38).

The control circuit 50 operates the solenoid valves 42, 46,
48 and electric pump 44.

Specifically, as shown in the flowchart shown in FIG. 3 after the engine is stopped, when the cooling water temperature detected by the water temperature sensor 53 drops to around the freezing point, the solenoid valves 46 and 48 are closed to stop the cooling water from flowing to the radiator 34. At the same time as blocking the inflow, the solenoid valve 42 is opened to allow the cooling water in the radiator 34 to flow down into the heat retention tank 40.

In this state, when a predetermined time (draining time of cooling water in the radiator 34) has elapsed, the electric motor 44 is driven to pump the cooling water in the heat retention tank 40 to the water tank 21, and the heat retention tank 40 is pumped up.
When the liquid level within falls to the level detected by the liquid level sensor 52, the electric pump 44 is stopped.

When starting the engine, the solenoid valve 42 is closed and the solenoid valves 46 and 4 are closed, as shown in the flow chart shown in FIG.
8 is opened to introduce cooling water into the radiator 34 using gravity, and the electromagnetic clutch 32 is turned off until the temperature of the cooling water in the water jackets 23 and 24 as detected by the water temperature sensor 53 reaches a predetermined value. The rotation of the cooling fan is stopped, and the electromagnetic clutch 32 is turned on only after warming up.

By the way, according to this embodiment, the engine main body 20
When the cooling water inside the insulated pipe 22 freezes, a portion of the cooling water that is pushed out due to the volume expansion accompanying freezing is transferred to the insulated pipe 22.
Since the cooling water is allowed to escape to the water tank 21 through the cooling water, cracks and damage caused by freezing of the cooling water in the cylinder block 26 and cylinder head 25 can be avoided.

In addition, in the cooling system of the engine body 20, all the cooling system circuits 39 except the radiator 34 and the engine body 20 are covered with a heat insulating material to keep them warm, and when there is a risk that the cooling water in the radiator 34 may freeze, Since this is drained into the heat insulating tank 40, freezing of cooling water other than the engine main body 20, that is, cracking and damage of the cooling circuit 39 can be prevented.

5 and 6 show other embodiments, respectively.
In the case of the figure, the insulated pipe 22A is the water tank 2
The cooling water jackets 23 and 24 in the water tank 21 are connected to the bottom of the
A check valve 60 is provided to prevent the water from flowing down.

The heat insulating pipe 22B in FIG. 6 includes two pipe portions (22Ba ) is formed.

7 and 8 show still another embodiment, in which the water jackets 23 and 24 of the cylinder head 25 and cylinder block 26 are replaced by a water tank, and are replaced by a heat insulating tank 4 disposed below the engine body 20.
0 through an insulated pipe 22C.

The heat insulating pipe 22C has two pipe parts 22Ca that protrude from the side of the engine body 20 toward the center of each water jacket 23 and 24 of the cylinder head 25 and cylinder block 26, and joins these parts halfway. It consists of a pipe part 22Cb communicating with the upper part of the heat retention tank 40, and a pipe part 2
A valve 61 that opens only when the pressure of the cooling water in the water jackets 23 and 24 increases due to freezing is interposed in the middle of 2Cb (downstream of the confluence part).

Of course, in these embodiments, other parts are the same as in the above embodiments, and the same effects are produced.

(Effects of the invention) In short, according to this invention, when the cooling water in the engine water jacket freezes, a portion of the cooling water expands in volume due to freezing and is covered with a heat insulating material through an insulated pipe. Since the cooling water is pushed out to the auxiliary tank, it is possible to prevent cracks and damage to the cylinder head and cylinder block caused by freezing of the cooling water without using antifreeze.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the engine body showing an embodiment of this invention, Figure 2 is a schematic diagram of the entire cooling system,
Fig. 3 is a flowchart showing an example of the control operation when the engine is stopped, and Fig. 4 is a flowchart showing an example of the control operation when the engine is started.
FIG. 5 is a sectional view of main parts showing another embodiment, FIG. 6 is a partial side view of the engine body showing another embodiment, and FIG. 7 is a sectional view of the engine main body showing yet another embodiment. FIG. 8 is a schematic diagram of the entire cooling system, and FIG. 9 is a diagram of the conventional device. 20... Engine body, 21... Water tank,
22, 22A, 22B, 22C...Insulated pipe,
23, 24...Water jacket, 40...Heat tank.

Claims (1)

[Scope of utility model registration request] A cooling system for a water-cooled internal combustion engine, characterized in that an auxiliary tank whose periphery is covered with a heat insulating material is provided, and this auxiliary tank is communicated with the water jacket via an insulated pipe extending into the center of the engine water jacket. cooling system for internal combustion engines.