JPH0245466Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to improvements in the cooling structure of engines, particularly water-cooled engines.

(Prior Art) Conventionally, an engine cooling structure includes a main cooling water passage that guides cooling water from the water pump to the hot zone of the engine, and a heater circulation branching from the passage and returning the water to the suction side of the water pump via a heating heater. The return cooling water passage from the engine is branched into a first passage leading to the radiator and a second passage called a bottom bypass passage that bypasses the radiator, and a cooling water temperature sensing valve is installed in the branch part. There is a known system in which the first passage is closed and the amount of cooling water introduced into the radiator is controlled until the cooling water temperature reaches a set value (see, for example, Japanese Patent Publication No. 55-29248).

In this type of engine cooling structure, when the coolant is not sufficiently warm, the radiator circulation passage is shut off by the coolant temperature sensing valve.
Since the return cooling water from the engine is directly returned to the suction side of the water pump through the bypass passage, overcooling of the engine is prevented. In addition, when the coolant temperature exceeds the set value, the radiator circulation passage is opened by the operation of the coolant temperature sensing valve, and after the return coolant from the engine passes through the radiator and is cooled, the water pump The cooling water is kept at an appropriate temperature.

(Problem to be solved by the invention) However, in the engine cooling structure described above, in order to guide the return cooling water from the engine and the heater to the suction side of the water pump, two long pipes are installed outside the engine. In addition, the thermostat valve for the cooling water temperature sensing valve is attached to the side wall of the engine, which makes it difficult to lay out the parts around the engine, and it is necessary to bend the pipes appropriately and provide seals at the joints. This has caused a problem in that manufacturing becomes troublesome. Furthermore, if these conduits are disposed on the exhaust system side of the engine, they will suffer from heat damage due to radiant heat from the exhaust manifold.

Therefore, the applicant proposed improvements to the method of forming the bypass passage from the cooling water passage in the cylinder head to the suction side of the water pump and the return passage from the heating heater to the suction side of the water pump in the heater circulation passage. As an engine cooling structure that facilitates the layout of parts around the engine and prevents heat damage from the exhaust system, the water pump is installed at one end of the cylinder block in the cylinder row direction, and A radiator circulation passage that circulates the cooling water led from the discharge side of the water pump to the main cooling water passage in the cylinder block and cylinder head to the radiator and then leads it to the suction side of the water pump, and the main cooling water in the cylinder head. A bypass passage that bypasses the radiator and guides the cooling water led to the passage to the suction side of the water pump, and a main cooling water passage in the cylinder head that circulates the cooling water to the heating heater. In the engine cooling structure, the engine cooling structure includes a heater circulation passage leading to the suction side of the water pump, and a cooling water temperature sensing valve that controls opening and closing of the radiator circulation passage or the bypass passage according to a change in the temperature of the cooling water. An application has previously been filed in which at least one of the heater circulation passages and the heater circulation passage includes an intra-cylinder block passage formed within the cylinder block and extending in the direction of the cylinder row.

The object of the present invention is to improve the cooling structure of the engine, balance the rigidity symmetrically when viewed from the engine cylinder row direction, and improve the vibration isolation and bending rigidity of the skirt portion.

(Means for Solving the Problems) The present invention includes a water pump provided at one end side in the cylinder row direction of the engine body, and a cooling water pipe that is guided from the discharge side of the water pump to the main cooling water passage in the engine body. a radiator circulation passage that circulates water through the radiator and then leads it to the suction side of the water pump; and a cooling water bypass that leads the cooling water led to the main cooling water passage to the suction side of the water pump bypassing the radiator. The lower deck of the cylinder block is composed of an upper outer wall portion and a skirt portion expanding outward from the lower end of the upper outer wall portion. The cooling water bypass passage is provided along the cylinder row direction on the other side of the lower deck facing the main oil gear extending in the cylinder row direction on one side of the lower deck and at the base of the skirt portion. do.

(Function) Since the cooling water bypass passage is formed at the base of the skirt part along the direction of the cylinder row, the cooling water bypass passage functions as a reinforcing rib, which improves the vibration isolation and bending rigidity of the skirt part. It will be done. Since the cooling water bypass passage is arranged symmetrically to the main oil gear, the stiffness of the lower deck in the cross-sectional direction can be made uniform, which is effective in damping vibrations in the skirt section.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. 1 to 5 show an embodiment in which the present invention is applied to a cooling device for a water-cooled four-cylinder transverse engine.

As shown in FIGS. 1 and 2 showing the engine cooling structure, a water pump WP is provided at one end side 11a in the cylinder row direction of the cylinder block deck 11 of the engine E.
Cylinder block deck 1 from the discharge side of the WP
1 and the main cooling water passage 13 in the cylinder head 12 is transferred to the radiator circulation passage 1.
4, the water is circulated to the radiator R and then led to the suction side of the water pump WP.
In addition, the main cooling water passage 13 in the cylinder head 12
A part of the cooling water guided to the radiator R bypasses the radiator R and is led to the suction side of the water pump WP through a cooling water bypass passage 15 (bottom bypass passage). Furthermore, a portion of the cooling water led to the main cooling water passage 13 in the cylinder head 12 is passed through the valve V to the heater circulation passage 16.
After being circulated to the heater H, the air is guided to the suction side of the water pump WP. A thermostatic valve TS is interposed in the radiator circulation passage 14 as a cooling water temperature sensing valve that controls opening and closing of the radiator circulation passage 14 according to changes in the temperature of the cooling water. The cylinder block deck 11 is composed of an upper outer wall and a skirt extending outward from the lower end of the upper outer wall.

The engine E has an exhaust manifold 17 attached to the side of the cylinder head 12 where the water pump WP is installed, and a thermostatic valve TS that is close to the water pump WP of the cylinder block deck 11 and communicates with the intake side. is provided.

The radiator circulation passage 14 is connected to the cylinder head 1
2, and a return side passage 14b that connects the radiator R and the valve casing 18 of the thermostat valve TS. , 14b are conduits 19, 2, respectively.
It is formed by 0.

On the other hand, the heater circulation passage 16 is a feed-side passage 1 that connects the main cooling water passage 13 in the cylinder block deck 11 and the heater H via a valve V.
6a, and a return passage 16b that connects the heater H and the suction side of the water pump WP.
They are formed by conduits 21 and 22, respectively.

The cooling water bypass passage 15 is shown in FIGS. 3 and 4.
As shown in the figure, inside the cylinder block deck 11 on the side where the exhaust manifold 17 is attached, there is an internal passage 15a arranged along the cylinder row direction at a position almost symmetrical to the main oil gear gallery OG, and the above-mentioned feed side passage 14a. The internal passageway 15 branches from the conduit 19 of the
The conduit 23 of the external passage 15b communicating with the intermediate part of a
It is composed of.

The internal passage 15a is controllably connected to a thermostatic valve TS at one end side 11a of the cylinder blockade 11, and is sealed by a blind screw plug 15c at the other end 11b of the cylinder blockade 11. ing.

Furthermore, as shown in FIG. 5, the internal passage 15a is provided vertically at approximately the middle of the cylinder block deck 11 in the cylinder row direction, and an oil return passage 25a is provided for guiding lubricating oil from the cylinder head 12 back to the oil pan. They alternate on the inside with a tube wall separating them, creating a structure that allows heat exchange.
By changing the oil return passage 25 from the cylinder head 12 to the oil pan to be adjacent to the cooling water bypass passage 15 in this way, the lubricating oil is warmed by the cooling water during a cold start, and warm-up is accelerated and warm-up is completed quickly. The lubricating oil can then be cooled down.

As shown in FIGS. 2 and 3, the thermostatic valve TS includes a main valve 32 that opens and closes the return passage 14b according to the temperature detected by the temperature sensor 31, and It has a bypass valve 33 that closes the internal passage 15a of the cooling water bypass passage 15 when the main valve 32 is opened at a position on the opposite side of the temperature sensing part 31. The thermostatic valve TS is housed and installed in a mounting recess 34 formed in one end side 11a of the cylinder block, with the bypass valve 33 facing the internal passage 15a and the communication opening.

Therefore, since the recess 34 for mounting the thermostatic valve TS is provided in the cylinder block deck 11, the number of sealing locations can be reduced and the case can be made more compact.

As mentioned above, the cylinder block deck 11 in which the internal passage 15a of the cooling water bypass passage 15 and the mounting recess 34 for the thermostat valve TS are formed is further provided with a balancer shaft (which cancels torsional vibrations of the crankshaft and camshaft). A pair of cylindrical chambers 35 and 36 are formed in the direction of the cylinder row. The internal passage 15a is formed at the base of the skirt portion, which is approximately symmetrical to the oil gear rally OG with respect to the midline that passes vertically through the crankshaft center in the cross section, and improves the vibration isolation and bending rigidity of the skirt portion. It has a tubular structure that is effective against.

Therefore, according to the above configuration, when the cooling water is not sufficiently warm, the return side passage 14b in the radiator circulation passage 14 is closed by the thermostat valve TS, so that the main cooling water in the cylinder head 12 is The cooling water that has passed through the passage 13 passes through the cooling water bypass passage 15 and is sent to the water pump.
Returned to the suction side of the WP. Therefore, cooling of the cooling water by the radiator R is prevented, and the engine E
This prevents overcooling and speeds up warm-up.
On the other hand, when the cooling water temperature exceeds the set value (for example, 80°C), the return side passage 14b of the radiator circulation passage 14 is opened by the operation of the thermostat valve TS, so that the main cooling water in the cylinder head 12 is The cooling water passing through the passage 13 is sent to the radiator R.
After cooling is allowed to pass through the thermostatic valve
It is returned to the suction side of water pump WP via TS. Therefore, the cooling water is kept at an appropriate temperature.

In addition to the above-described embodiments, when the transmission (not shown) connected to the end 11b of the cylinder block rod is made smaller and space is secured, the blind screw stopper 15c is removed and the end It is also possible to connect the external passage 15b to the main cooling water passage 13 in the cylinder head 12 to make the layout of parts around the engine easier. It goes without saying that it can also be constructed as a passage and connected to the internal passage 15a.

(Effects of the invention) As described above, the present invention provides a cylinder block on the other side of the lower deck facing the main oil gear extending in the cylinder row direction, and on the base of the skirt portion. ,
Since the cooling water bypass passage is provided along the cylinder row direction, the long external conduit for the bypass passage that runs along the side of the outside of the engine can be shortened or omitted without making complicated bends. , the layout of parts around the engine becomes easier. In addition, the stiffness of the lower deck is almost symmetrical and almost uniform when viewed from the direction of the cylinder row, making it possible to improve the stiffness without increasing the engine weight.As a result, the vibration of the skirt section is effectively reduced, and the bending stiffness is improved. This makes it possible to improve the

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a cooling system diagram of the engine cooling structure, Fig. 2 is a partial cross-sectional plan view showing the cooling water bypass passage, and Fig. 3 is a diagram of the cylinder block deck. Front view, Figure 4 is a sectional view taken along the - line in Figure 3, and Figure 5 is a cross-sectional view taken along the - line in Figure 3.
It is a partial sectional view taken along the - line in the figure. 11...Cylinder block deck, 13...
...Main cooling water passage, 14...Radiator circulation passage,
15... Cooling water bypass passage, E... Engine,
WP...Water pump, OG...Main oil gear, R...Radiator, TS...Thermostat valve.

Claims (1)

[Scope of Claim for Utility Model Registration] A water pump installed on one end side in the direction of the cylinder row of the engine body, and cooling water guided from the discharge side of the water pump to the main cooling water passage in the engine body and circulated to the radiator. and a cooling water bypass passage that guides the cooling water led to the main cooling water passage to the suction side of the water pump, bypassing the radiator. In the engine, the lower deck of the cylinder block is constituted by an upper outer wall portion and a skirt portion expanding outward from the lower end of the upper outer wall portion, and the lower deck of the cylinder block is configured to extend in the cylinder row direction on one side of the lower deck of the cylinder block. An engine cooling structure characterized in that the cooling water bypass passage is provided along the cylinder row direction on the other side of the lower deck facing the extending main oil gear gallery and at the base of the skirt portion.