JPS61167111A - Engine cooling device - Google Patents

Abstract

PURPOSE:To prevent the under-cooling of a cylinder block while sufficiently cooling a cylinder head by forming the cooling water jacket of the cylinder head and that of the cylinder block separately, and connecting the inlet and outlet of both jackets respectively. CONSTITUTION:In a cooling device of an outboard machine the cooling water jacket 17a of a cylinder head 17 and the cooling water jacket 19a of a cylinder block 19 are formed separately. And, the cooling water inlet 17b of the cylinder head is connected to the cooling water outlet 19c of the cylinder block via a float valve 54 and a thermostat T2, and the cooling water outlet 17c of the cylinder head is connected to the cooling water inlet 19b of the cylinder block via a thermostat T1 and a throttle 56. Thus, the temperature of the cylinder head and cylinder block can be controlled at a temperature in compliance with the respective requirements.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a cooling device for an engine used, for example, in an outboard motor.

(Prior Art) Generally, an outboard motor draws in seawater as cooling water, and the engine is directly cooled with the drawn seawater. For this reason, there is a tendency for the cylinder block portion, which generates a relatively small amount of heat, to become overcooled.

Incidentally, in recent years, diesel engine outboard motors using diesel engines have been developed. When the above-mentioned direct seawater cooling structure is applied to this diesel engine outboard motor, the following problems occur. In other words, diesel fuel contains sulfur, and when the sulfur burns, sulfur dioxide gas is generated.If a diesel engine, which is filled with sulfur dioxide gas, is directly cooled with relatively low-temperature seawater, for example, A problem occurs in which the cylinder head etc. become extremely low temperature, condensing the sulfur dioxide gas and producing LA acid, causing so-called sulfuric acid corrosion.This problem is particularly noticeable at low loads when the heat generated from the diesel engine is low.
When a diesel engine outboard motor is used for fishing, it is often used under low loads, so there is a problem that the wear of the cylinder liner due to sulfuric acid corrosion increases.

It is also well known that keeping the cylinder head temperature low increases volumetric efficiency due to the low intake air temperature, and keeping the cylinder block at an appropriate temperature reduces mechanical loss, resulting in a high-output engine with low fuel consumption. There is a need for a cold IJI system that sufficiently cools the head and prevents overcooling of the cylinder block.

(Object of the Invention) An object of the present invention is to provide an engine cooling device that can sufficiently cool a cylinder head that generates a large amount of heat and can prevent overcooling of a cylinder block.

(Structure of the Invention) The present invention is characterized in that the cooling water jackets 1 to 1 of the cylinder head and the cooling water jacket of the cylinder block are formed separately, both cooling water jackets are provided with a cooling water inlet and an outlet, and both the cooling water jackets are provided with cooling water inlets and outlets. This is an engine cooling device characterized in that the inlet and outlet of the engine are connected.

(Example) In Fig. 1, which shows the case where the present invention is applied to a diesel engine and mounted on an outboard motor, d'3 is a hull, and 10 is a hull.
An outboard diesel engine 11171 is attached to the rearmost portion of the hull 10 via a bracket 12. The diesel engine outboard motor 14 has a structure in which a diesel engine 16 and a drive unit 18 are combined.The diesel engine 16 is covered with a cowling 20, and the drive units 1 to 18 are provided with propellers 22.

The diesel engine outboard motor 1/'I is connected to the shaft 2/'I of the bracket 12 via an arm 23 superimposed on the bracket 12.
It is mounted so that it can rotate freely around the shaft 24 (it is pulled), and when the propeller 22 is tilted upward from the water or when the drive unit 18 collides with an obstacle such as a rock, the diesel engine is rotated around the shaft 24. The entire 114 is rotatable.

The diesel engine 16 is fixed with the crank @ 15 arranged vertically, and the diesel engine 16
The cylinder head 17 and cylinder block 19 are arranged in parallel in the lateral direction. The cooling water jacket 1-178 of the cylinder head 17 is formed to allow cooling water to flow in the vertical direction, and the cooling water jacket 19a of the cylinder block 19 is similarly formed.

The seawater supplied to the cooling water jackets 17a, 19a is pumped by a seawater pump 28 in the drive unit 18, and is discharged into the water through a passage 30 in the drive unit 18 after cold IA. An exhaust pipe 32 of the diesel engine 16 also opens into the passage 30.

A first embodiment of the cooling system for the diesel engine 16 will be described with reference to FIG. In this embodiment, the temperature of the seawater flowing through the cooling water jacket 1'7a is controlled to t2, and the temperature of the seawater flowing through the cooling water jacket 19a is controlled to t3 (t2).
<t:3).

The seawater pumped up by the seawater pump 28 has a low temperature, t□ (t2>tO). cylinder head 17
A cold JI water inlet 17b is formed in the upper part of the cylinder head 17, a cooling water outlet 17c is formed in the lower part of the cylinder head 17, and the seawater pump 28 and the cooling water inlet 17b are connected by a passage 40. A thermostat T1 is provided near the cooling water outlet 17c, and the valve opening temperatures of the thermostats 1 to T1 are set to t2. 1 No-mostat T1
and the cooling water population 19b of the cooling water jacket 19a is the passage 4.
2, and the cooling water port 19b is installed at the bottom of the cylinder block 19. An auxiliary cooling water outlet 19G and a main cooling water outlet 19d are provided at the upper end of the cooling water jacket 19a, and a thermostat ]-2 is arranged near the auxiliary cooling water outlet 19c. In addition,
A thermostat 1-T1 may be provided near the main cooling water outlet 19d.

Therefore - cooling water jacket 1 to cylinder head 17a
Seawater flows downward from the cooling water outlet 17b toward the cold 231 water outlet 17C, and the cooling water outlet 19a
The seawater flows upward from the cold IJ1 water inlet 19b toward the main cooling water outlet 19d (14-frame construction).

The valve opening temperature of the thermostat T2 is t3, and the thermostat T2 has a passage 4. One end of /I is connected, and the (ljl end of passage 44 is connected to passage 30 (FIG. 1).

As described above, when the thermostat T1 (valve opening temperature t2> is installed near the main cooling water outlet 19d), one end of the passage 46 is connected to the thermostat T1, and the passage 46
The other end is the passage/! It is connected in the middle of 4. aisle 46
A switching valve 48 is interposed in the middle of the cylinder block, and during high load when the heat generation t1 of one cylinder block increases, the switching valve 48 is closed.
The valve is opened to flow seawater at a temperature of t2 into the cooling water jacket 19a, and when the cylinder block 19 has a low calorific value, such as during idling, when the load is low, the switching valve 48 is closed to flow seawater at a temperature of t3 into the cooling water jacket 19a. It is designed to flow like warm seawater. The switching valve 118 is opened and opened manually or automatically.

Note that normally, when a thermostat T1 is installed at the cooling water outlet 17b, a thermostat T1 is installed at the main cooling water outlet 19d.
1 is not provided, and a thermostat T1 is provided at either the cooling water population 17b or the main cooling water outlet 19d.

The passage /l/l and the passage 40 are communicated by a bypass passage 50, and the end of the bypass passage 50 is connected to a water inspection hole (not shown) for checking the normal operation of the cooling water pump. .

The lower end of the passage 52 is connected to the upper part of the cooling water jackets 1 to 17a, and the upper end of the passage 52 is connected to the middle of the passage 44. A float valve 54 for venting air is interposed in the middle of the passage 52, and is configured to discharge air accumulated in the cooling water jacket J-17a from the float valve 54.

Further, one end of a drain passage 58 having a throttle 56 is connected to the lower part of the cold 711 water jacket 17a, and the lower end of the drain passage 58 is connected to the middle of the passage 42.

There is also an air vent 1 on the top of the cooling water jacket 19a.
] - The lower end of the passage 62 to the right of the gate valve 60 is connected, and the upper end of the passage 62 is connected to the middle of the passage 4/I. Also, a reverse mountain valve 64 is provided between the passage 42 and the bypass passage 50.
A passageway 66 having a diameter is connected thereto. A throttle 68 is interposed near the left side in the figure of the connection point p between the passage 66 and the bypass passage 50, and when the switching valve 48 is in the closed state, the thermostat T1 is in the open state, and the thermostat T2 is in the closed state. However, the check valve 64 does not open due to the pressure of seawater from the cooling water jacket 17a, and the seawater in the cooling water jacket 17a remains in the cooling water jacket 17a until the temperature reaches a ratio of 1:3 at which the thermostat T2 opens. It will stay in.

Also, when cooling water jacket 17 is stopped, cooling water jacket 17
It is common for outboard motors to discharge the seawater in the a1 cooling water jacket 19a, but when the diesel engine 16 is stopped, the check valve 64 opens due to the weight of the seawater and the passage 30
It is designed to be discharged.

Next, the effect will be explained. First, if the throttle 68 is provided on the left side, when the switching valve 48 is closed, for example during idling,
The cold 711 water jacket 19a is temperature controlled at 1°3. In other words, the seawater flowing into the cooling water population 17b from the seawater pump 28 at a temperature of 10 mixes with the relatively high temperature seawater that has gathered at the top due to the convection phenomenon in the cooling water jacket l-17a, and reaches a temperature of tl. Become. The temperature of the seawater that has flowed into the cooling water jacket 17a rises with a relatively small temperature gradient from tl to t2, and at the temperature of t2, the thermostat T1 of the cylinder head 17 opens, but the check valve 64 detects the pressure of the seawater. The valves remain closed, and the thermostats 1 to T2 of one cylinder block also remain closed, and the seawater remains stagnant. As it cools down, the temperature of the jacket 19a rises, and the temperature of the thermostat 1-T rises to 1:3.
2 opens, the seawater from the cooling water jacket 17a flows from the cooling water inlet 19b toward the auxiliary cooling water outlet 19G, and the passage 41! I is discharged into the passage 30.

Therefore, when idle, that is, when the switching valve 18 is closed, the seawater temperature is controlled to a relatively high temperature 13 by the thermostat T2, and there is no possibility that the aforementioned sulfuric acid corrosion will occur on the cylinder liner of the cylinder block 19. do not have.

On the other hand, when the load is high when sailing at full power, the switching valve 48 is opened and the seawater in the cold 7J1 water pipes 1 to 19a is changed to the cooling water population 19b.
The water flows from there toward the main cooling water outlet 19d and is discharged from the passage 46 to the passage 30.

Therefore, when idling, that is, when the switching valve 48 is closed,
The seawater temperature is set to a relatively high temperature t3 by thermostat T2.
Temperature control is maintained to ensure that there is no risk of the above-mentioned sulfuric acid corrosion occurring on the cylinder liner of one cylinder block.

On the other hand, when sailing at full power, the switching valve 48 is opened and the cooling water 41 is turned on, and the seawater in the jacket 19a flows from the cooling water port 19b toward the main cooling water outlet 19d, and is discharged from the passage 46 to the passage 30.

Therefore, when the switching valve 48 is open, the temperature is controlled by the thermostat T1. Since the amount of heat generated from the cylinder block 19 increases during this high load, there is no risk of sulfuric acid corrosion occurring even if the temperature is controlled at a relatively low temperature t2.

On the other hand, the cylinder head 17a is cooled 7JI at a low temperature t2 to cool the intake boat (not shown) of the cylinder head 17 to low humidity to improve the filling efficiency of the intake air. (not shown), etc., is also reduced.

Another embodiment will be described in which the diaphragm 68 is arranged on the right side of the connection point p as shown by the broken line in the figure. When switching valve/1.8 is closed, thermostat 1~
When T1 is open and Mostat T2 is closed, coolant water is pumped through passage 4.
2, the passage 66, the bypass passage 50, and the passage 44 are sequentially passed through, and the JJI is output at 30. Zunawara cold n1 water jacket 17a (yothermostat 1-T
1, the humidity of the cooling water jack 19a is controlled by the thermostat T2.

On the other hand, when the switching valve 48 is closed during idle, etc., the cooling water jacket 17a is 1"2, and the cold IJ + water I7 is
19a is temperature controlled at t3. In other words, the seawater flowing into the water inlet 17b from the seawater pump 28 at a temperature of to mixes with the relatively high temperature seawater that has gathered at the top due to the convection phenomenon in the cooling water jacket 17a, and reaches a temperature of tl. . The seawater flowing into the cooling water tank 17a is t.
The temperature increases with a relatively small temperature gradient from 1 to 12,
Thermostat T1 of cylinder head 17 at temperature t2
When the valve is opened, the check valve 64 is opened by the pressure of the seawater, and the seawater is discharged into the passage 30 through the passage 42, the passage 66, and the bypass passage 50.

On the other hand, if the thermostat T1 is installed near the main cooling water outlet 19d (or if the thermostat T1 near the cooling water outlet 17c is removed), the length of the passage 42 is shortened and it can be inserted into the cylinder head 17 and cylinder block 19. Can be cast in one piece by casting.

Eventually, when the temperature of the seawater in the cooling water jacket 19a increases from t2 to t13, the thermostat T2 opens, and the seawater from the cooling water jacket 17a reaches the cooling water population 19b.
The cooling water flows from there toward the auxiliary cooling water outlet 19c and is discharged from the passage 44 to the passage 30.

Therefore, there is no risk that the cylinder liner of one cylinder block will undergo the aforementioned sulfuric acid corrosion.

- Thoroughly ensured) During high loads such as during J navigation, the amount of heat generated from the cylinder block 19 increases even if the switching valve /'18 is opened and the cylinder block 19 is controlled at 1:2'IQW. , there is no risk of sulfuric acid corrosion occurring. On the other hand, the cylinder head 17 is cooled to a low temperature t2, and the intake boat (not shown) of the cylinder head 17 is cooled to a low temperature to improve the intake air filling efficiency, and the cylinder block 19 is cooled to a relatively high temperature. 13, and the heat load between the intake and exhaust valves (not shown) of the cylinder head 17 is also reduced.

Regarding the materials of the cylinder head 17 and one cylinder block, the cylinder head 17 may be made of aluminum alloy, which has a good heat transfer coefficient, and the cylinder block 19 may be made of cast iron, which has a relatively poor heat transfer coefficient. can.

The cylinder head 17 is not limited to the case where the cylinder head 17 is made of aluminum alloy and the cylinder block 19 is made of cast iron.
Both the cylinder block and the cylinder block may be made of aluminum alloy. In this case as well, since the temperature of the cylinder tab 19 is controlled by the temperature control 1-T2 during idling, the problem of overcooling of 7 Jl does not occur.

Further, the cylinder head 17 and one cylinder block are integrally molded, and cooling water jackets 1 to 17a for cooling the cylinder head 17 and cooling water jackets 1 to 19a for cooling one cylinder block are formed inside. But J: No. In this case, since the position of the partition wall between the cooling water shag h17a and the cooling water jackets 1 to 198 can be freely shifted, it is possible to strictly control the partial temperature of the cylinder head 17 and one cylinder block. can be done.

Next, a modification of the first embodiment will be described with reference to FIGS. 2a to 2c. In the case of Figure 2a, cylinder head 1
Thermostats 1 to T1 are provided at the lower part of the cooling water jacket 17a to control the outlet temperature of the cooling water jacket 17a. In the case of FIG. 2b, a thermostat T2 is provided at the top of the cylinder block 19 to control the outlet temperature of the cold 2JI water pipe V-ket 19a. Further, in FIG. 2C, seawater is made to flow from the bottom toward the cooling water jacket 17a of the cylinder head 17, and the cylinder block 19
The cooling water jacket 19a is designed to allow seawater to flow downward from -.

Further, a second embodiment of the present invention will be described with reference to FIG.

In FIG. 3, parts given the same reference numerals as those in FIG. 2 indicate the same or equivalent parts.

In Figure 3, the seawater flow direction of the cold 2J1 water outlet 17a is upward from the bottom to the top.
-198 shows the case where the seawater flow direction is upward from the bottom to the top. Like this cold water jacket 1
~17a, When the seawater flow direction of both the cold water pipes 17 and 19a are directed upward, the cooling water pipes A7 and 17a, .
There is no risk of air remaining in the middle of the cooling water jacket t-19a, which is advantageous in terms of air bleeding.

3a shows a case in which a thermostat T1 is provided in the second part of the cylinder head 17, and FIG. 3b shows a case in which a small thermostat T2 is provided in the upper part of the cylinder block 19.

(Effects of the Invention) As explained above, the engine cooling device according to the present invention has a cold 2JI water jacket in the cylinder head and a cooling water jacket in the cylinder block formed separately, and cooling water in both cooling water jackets. If the inlets and outlets of both cooling water jackets are connected, it becomes possible to control the temperature of the cylinder head 17 and cylinder block 19 according to their respective requirements, and is made of an aluminum alloy with good cooling efficiency, and the cylinder head 17 is cooled to a low temperature, and the cylinder block 19 is
The cylinder head is made of cast iron and can be maintained at a temperature that prevents sulfuric acid corrosion.

Furthermore, when the cylinder head 17 is made of an aluminum alloy, the coefficient of thermal expansion of the cylinder head 17 becomes large, and sealing at the joint between the cylinder head 17 and the cylinder block 19 becomes a problem. Jacket 17a and one cylinder block cooling water population 19b
Since the gaskets are separated from each other, there is no need to form a cooling water passage in the gasket (not shown) between the cylinder head 17 and the cylinder block 190, so corrosion of the gasket by seawater can be prevented, and the gasket can be protected from combustion gas. It is advantageous for gasket design because it is difficult to seal only with lubricating oil. When the cylinder head and cylinder block are made of aluminum alloy, it is very advantageous in reducing the weight of the engine, but on the other hand, due to the difference in thermal expansion coefficient of gasket materials such as aluminum alloy, and the low rigidity of aluminum alloy, dη water direct cooling It is known that gasket problems occur frequently in the case of However, if the present invention is adopted, the gasket design is advantageous as mentioned above, and both the cylinder block and cylinder head are made of aluminum alloy even when directly cooled in seawater, and a lightweight engine can be provided without the gasket problem. Yes, but the cylinder block 19 has a thermostat T.
2, the temperature of the cylinder block 19 can be maintained at an appropriate temperature.

When a cylinder head 17 and a cylinder block are integrally molded, and a cooling water jacket 17a for cooling the cylinder head 17 and a cooling water jacket 19a for cooling the cylinder tab 19 are separately formed inside. Since the position of the partition wall between the cooling water jacket 17a and the cooling water jacket 19a can be freely shifted, it is possible to precisely control the partial temperature of the cylinder head 17 and the cylinder block 19.

(Another Embodiment) (1) The present invention is not limited to the case where it is applied to a diesel engine outboard motor as described above.
5 is applicable to other engines, such as gasoline engines, which are used in a longitudinally arranged position. However, when applied to a diesel engine outboard motor, problems such as the aforementioned sulfuric acid corrosion can be solved, making it optimal.

[Brief explanation of drawings]

Claims (4)

[Claims] (1) The cylinder head cooling water jacket and the cylinder block cooling water jacket are formed separately, both cooling water jackets are provided with cooling water inlets and outlets, and the inlets and outlets of both cooling water jackets are connected. An engine cooling system featuring: (2) The engine cooling device according to claim 1, wherein at least the cylinder head is made of an aluminum alloy. (3) The engine cooling device according to claim 1, wherein the cylinder head and cylinder block are made of aluminum alloy. (4) The engine cooling device according to claim 1, wherein the cylinder head and cylinder block are integrally molded.