JP2566051B2 - Water-cooled engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water-cooled engine in which a sacrificial electrode is provided in a water jacket of a cylinder block or a cylinder head.

(Prior Art) A water-cooled engine mounted on an outboard motor cools by directly sending seawater or the like into a water jacket of a cylinder block and a cylinder head.

A sacrificial electrode called anode metal is provided in the water jacket to prevent the corrosion of cylinder blocks and cylinder heads made of metals such as iron and aluminum alloys due to the effects of salt in seawater. To be done.

As conventional techniques, for example, in the technique disclosed in Japanese Patent Laid-Open No. 58-44252, the technique disclosed in Japanese Utility Model Laid-Open No. 63-135966, and the like, a water jacket molding used at the time of casting molding of a cylinder block or a cylinder head. Using the sand removal hole and core holding hole, etc., the anode metal is inserted from the outside from the hole, and it is attached with a blind plug or bolt that closes the hole.

Further, as another technique, in the technique disclosed in Japanese Patent Laid-Open No. 60-1358, a technique in which anticorrosion zinc constituting a sacrificial electrode is provided above and below the same position inside a lid facing a water jacket provided outside the cylinder head Is disclosed. Makoto Kosho 59
As a technique disclosed in Japanese Patent No. 3138, a zinc mounting bolt is externally screwed into a part of a cylinder block through a screw hole, and the tip of the mounting bolt is exposed to a water jacket provided inside the cylinder block. Attach anticorrosion zinc to the tip.

(Problems to be solved by the invention) Incidentally, although the anode metal gradually disappears as it is used, unlike the case where the anode metal is attached to the outside of the case of the outboard motor, the anode metal is provided in the water jacket. In this case, the life cannot be discerned at a glance from the outside, so it is desirable to use as large an anode metal as possible to keep the rustproof effect for a long time.

However, as described above, in the conventional technique, the anode metal is inserted from the outside through the hole and is attached with a plug or a bolt that closes the hole, so that the outer diameter of the anode metal needs to be smaller than the hole. Further, when the elongated anode metal is used, the attachment points for the water jacket, which has many geometrical restrictions, are limited. Furthermore, even if a plurality of anode metals are provided above and below the lid of the water jacket in the cylinder head part, they are provided in a part of the water jacket passage and adjacent to each other, which is effective in a long water jacket passage. It is difficult to obtain good corrosion protection.

The present invention has been made to solve the above problems of the prior art, in the place where the rust preventive effect in the water jacket of the engine can be obtained, without being subject to shape restrictions and size restrictions as much as possible. The purpose of the present invention is to obtain a water-cooled engine that enables an effective and relatively large sacrificial electrode to be arranged and has an excellent rust prevention effect.

(Means for Solving the Problems) In order to solve the above problems, the present invention is provided with a water jacket that is opened and closed by a thermostat 61 provided in the upper part of the engine 21, and the range of the water jacket upstream of the thermostat. In the water-cooled engine in which the sacrificial electrode is provided, the water jacket is provided in the cylinder block 24, and the cylinder surrounding portion 55 provided so as to surround the circumference of the cylinder 25 and the cylinder surrounding portion 55 are provided in the cylinder block 24. An outer portion 56 that is in communication with the cylinder surrounding portion 55 and that is provided outside the cylinder surrounding portion 55; and a combustion chamber surrounding portion 57 that is provided in the cylinder head 28 and that communicates with the cylinder surrounding portion 55; and a cylinder head 28. An outer portion 79 provided outside the combustion chamber surrounding portion 57,
The cylinder block 24 and the outer portion 56 of the cylinder surrounding portion 55 of the cylinder head 28 and the outer portion 79 of the combustion chamber surrounding portion 57 are respectively recessed to the outside of the cylinder block 24 and the cylinder head 28. And each of the open recesses is provided with a lid member 67, 47 for closing each of them, and each lid member 67,
The sacrificial electrodes 71 and 81 described above are provided in the cooling water passages surrounded by the 47 and the recesses, and the sacrificial electrode is one of the sacrificial electrodes 7.
One side of the engine 21 is arranged in the lower part of the engine, and the other sacrificial electrode 81 is arranged in the upper part of the engine 21 on the other side of the engine 21 opposite to the sacrificial electrode 71.

Further, according to the present invention, one of the concave portions opened to the outside is a concave portion on the exhaust passage 38 side provided on the cylinder block 24 side, and the cooling water passage of the cylinder block including the concave portion covers the cooling water cover 67. And the other is a recess of the intake passage 37 provided on the cylinder head 28 side, and the cooling water passage of the cylinder head including the recess is closed by the intake manifold 47.

Further, according to the present invention, the crankshaft 22 is placed substantially vertically as a water-cooled engine.

(Function) Cylinder block portion of the water jacket provided on the cylinder block A concave portion that opens to the lower outside on one side of the engine facing the cooling water passage on the outer side, and a combustion chamber surrounding portion of the water jacket provided on the cylinder head A sacrificial electrode is provided in each of the recesses that are open to the upper outer side on the side opposite to the engine facing the cooling water passage in the outer portion. For this reason, the sacrificial electrode may be provided with relatively large anode metal on the cylinder peripheral wall portion in the water jacket, both side portions of the cylinder head, and the upper and lower portions without being restricted by the shape and the mounting position. it can.

Further, since the lid member that closes each recess from the outside is the cooling water passage cover that closes the engine side portion on the exhaust passage side and the intake manifold, a dedicated lid member for housing and closing the sacrificial electrode is provided. It is not necessary to prepare, and the recess for disposing the sacrificial electrode can be closed by using the cooling water passage cover and the intake manifold.

Therefore, particularly in the outboard motor, since a relatively large anode metal can be provided in the water jackets on both sides of the engine peripheral wall, the rust prevention effect is enhanced.

(Examples) Examples will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic side view showing an outboard motor with an engine cover portion cut away as an example to which the present invention is applied, FIG. 2 is a cross-sectional plan view of an essential part of an engine, and FIG. 3 is the opposite side of FIG. Fig. 4 is a side view of the engine head seen from the side of the cylinder head seen from the intake manifold connecting surface, Fig. 5 is a front view showing the cylinder head connecting surface of the intake manifold, and Fig. 6 is a cylinder block. FIG. 7 is a side view of a main part as viewed from the cooling water passage cover coupling surface, and FIG. 7 is a front view showing the cylinder block coupling surface of the cooling water passage cover.

In FIG. 1, 1 is a rear part of a hull, 2 is an outboard motor mounting device, 5 is a propeller screw, 6 is a propeller shaft, 7 is a bevel gear device, 8 is a vertical shaft, 9 is a water pump, 11 is a gear case, and 12 is a gear case. Extension case, 13
Is an engine cover and 21 is a water-cooled 4-cycle engine.

The mounting device 2 is composed of a swivel case 3 connected to the extension case 12 via a swivel joint and a stern bracket 4 connected to the swivel case 3 via a tilt pin. To be done.

As shown in FIGS. 2 and 3, the engine 21 supports the vertical crankshaft 22 between the joints between the crankcase 23 and the cylinder block 24, and
Has three cylinders 25 arranged in series in the vertical direction with its axis lined in the horizontal direction, where 26 is a piston and 27 is a connecting rod.

A cylinder head 28 is connected to the top of the cylinder block, and a head cover 29 is connected to the cylinder head 28. Between the cylinder head 28 and the head cover 29, a vertical cam shaft 31 and a rocker shaft 32 are arranged,
33 is a rocker arm, 34 is an intake valve, 35 is an exhaust valve, 36 is a combustion chamber, 37 is an intake passage, and 38 and 39 are exhaust passages.

Below the engine 21, a drive gear 41 provided at the lower end of the crankshaft 22 and a driven gear 42 spline-fitted at the upper end of the vertical shaft 8 mesh with each other, and the vertical shaft 8 serves as the crankcase 23 and the lower surface of the cylinder block 24. As a result, the upper portion of the primary gear case 43 is coupled to the primary gear case 43, and 44 is an oil pan coupled to the lower surface of the primary gear case 43. The vertical shaft 8 passes through the inside of the extension case 12 connected to the lower surface of the primary gear case 43, and within the gear case 11 connected below the extension case 12, the driving force is transmitted to the propeller shaft 6 via the bevel gear device 7.

Above the engine 21, the crankshaft 22 and the camshaft 31
A timing belt device (not shown) is installed between
Is the timing belt cover and also the crankcase
A starter motor 46 is attached to the upper part of 23.

In the cylinder head 28, an intake manifold 47 is connected to one side surface where each intake passage 37 is opened by a bolt 49, and a carburetor 51 is connected to each branch pipe 48 of the intake manifold 47. The carburetor 51 is an intake silencer pipe. Connected to 53, 52
Is a throttle valve.

As shown in FIG. 1, a cooling water intake port 14 is opened in the gear case 11 below the extension case 12, and a screen 14a is provided in the cooling water intake port 14. Inside the gear case 11 and the extension case 12, a cooling water conduit 15 is provided vertically, and in the middle of the cooling water conduit 15,
Water pump 9 driven by vertical shaft 8
Is interposed. The upper end of the cooling water conduit 15 is connected to the cooling water passage 16 formed longitudinally in the primary gear case 43, 44a is a grommet, and 44b is a conduit mounting flange integrally formed in the oil pan 44.

As will be described later, the cooling water that has passed through the inside of the engine 21 is
From the drain passage 17 vertically formed in the primary gear case 43, through the extension case 12 and the drain passage 18 vertically provided in the gear case 11, the water is discharged to the outside from the drain port 19 opened on the single surface of the boss portion of the propeller screw 5. .

Next, the cooling water passage structure inside the engine 21 will be described.

As shown in FIG. 1, FIG. 2, and FIG. 6, the cooling water passage 16 of the primary gear case 43 has the cylinder block 24.
It is connected to a cooling water passage 54 opened on the lower surface.

From this cooling water passage 54, cooling water is provided around the cylinder 25 in the cylinder block 24 and surrounds the cylinder 25 to the cooling water passage 55 (the cylinder surrounding portion of the water jacket) and the cooling water passage 56 around the exhaust passage 39. Flowing. Further, a cooling water passage 57 (a portion surrounding the combustion chamber of the water jacket) around the combustion chamber 36 in the cylinder head 28, and an exhaust passage 28
The above-described cooling water also flows into the surrounding cooling water passage 58, and these cooling water passages communicate with each other.

The cooling water passages 55, 56 in the cylinder block 24 and the cooling water passages 57, 58 in the cylinder head 28 communicate with each other as described above.
Passes through a thermostat 61 provided on the upper surface of the cylinder block, and 62 is a cap. Therefore, the thermostat
The cooling water passage 61 is disposed on the downstream side of the water jacket, and the cooling water passage is provided on the upstream side of the thermostat 61.

After passing through the thermostat 61, the cooling water passes through the drainage passages 63, 64, 65 on the exhaust passage 38 side of the cylinder block 24, and is drained from the drainage passage 17 of the primary gear case 43 connected to the drainage passage 65 opening on the lower surface of the cylinder block 24. It is discharged to the outside of the engine 21 as described above.

In the above, on one side surface of the cylinder block 24, the cooling water passage 56 on the side of the exhaust passage 39 and the drainage passage 64 are formed to be open, that is, the cooling water passage 56 and the drainage passage 64 are The outer wall of the cylinder block 24 is formed as a recess.

The cooling water passage 56 and the drainage passage 64 are as shown in FIG. 6, and mounting seats 66 are formed around these passages 56, 64.
The cooling water cover 67 connected to the mounting seat 66 is as shown in FIG. 7, and recesses 68, 69 corresponding to the passages 56, 64 are formed on the inner surface facing the mounting seat 66.

Of the above cooling water passages, the cooling water passage leading to the intake 14
An anode metal 71, which is a sacrificial electrode, is attached and disposed in a lower portion (lower portion of the engine 21) of the introduction side cooling water passage 56 facing the downstream side of 16. The sacrificial electrode is, for example, a cylinder block
24, when the cylinder head 28 is made of an aluminum alloy or the like, a metal having a greater ionization tendency than these metal materials is used.

As described above, the anode metal 71 is attached and arranged at a recess formed by one side surface of the cylinder block 24, that is, the cooling water passage 56 that opens to the outside on the exhaust passage 38 side. On the side surface, as shown in FIG. 6, a lower portion of the cooling water passage 56 (lower portion of the engine 21),
Specifically, as shown in FIG. 6, a cooling water passage for communication, which is opened in the lower surface of the cylinder block 24 that connects the cooling water passage 16 on the intake side and the cooling water passage 56 below the recessed portion forming the cooling water passage 56.
It is installed in the upper part close to 54.

The anode metal 71 disposed below the recess forming the cooling water passage 56 is removably attached to a boss 72 provided in the lower portion of the recess with a screw 73.
It is closed by a cooling water cover 67 connected to the relevant portion of the cylinder block 24 by a bolt 74 so as to close the recess via the mounting seat 66.

As described above, the anode metal 71 is on one side of the engine 21 in the engine water jacket.
The cooling water passage 56 is provided in a portion corresponding to a lower portion of the engine 21, and is provided in a cooling water passage 56 on the cooling water introduction side on one side surface of the cylinder block 24 of the engine.
Is provided with a recess opening to the outside of the cylinder block 24, and the recess is connected to the side surface of the cylinder block 24 with a cooling water cover 67.
Is blocked by.

In the figure, an exhaust passage 38 is provided on one side of the cylinder block 24, and in the embodiment, is provided in the cooling water passage of the lowest one of the three-cylinder cylinders above and below, and the exhaust passage 38 gathers at an exhaust passage 39 at the exhaust downstream (first 2), the corresponding cooling water passage is large in order to efficiently cool this portion. Therefore, as shown in FIGS. 1 and 6, the cooling water passage 56 is Since the volume of the lower portion is large and the anode metal 71 is provided in this portion, there are few restrictions on the shape of the anode metal, any shape can be used, and a large one can be installed. It will be possible.

On the other hand, as shown in FIG. 2 to FIG.
The other side of 28, that is, the cooling water cover 56 of the engine 21 described above.
A mounting seat 75 that uniformly surrounds each intake passage 37 is formed on the surface opposite to the cooling water passage 56 covered with. Recesses 76, 76 located between the intake passages 37 are formed on the surface of the mounting seat 75. The recesses 76, 76 communicate with the cooling water passage 57 on the combustion chamber 36 side through a through hole 77.

Further, as shown in FIG. 5, the connecting surface of the intake manifold 47 to the cylinder head 28 has a recess corresponding to the recess 76.
78, 78 are formed. Therefore, when the intake manifold 47 is connected to the mounting seat 75 on the side surface of the cylinder head 28 by the bolt 49, cooling water passages 79, 79 are formed therebetween.

The anode metal 81 is attached by a screw 83 to a boss portion 82 formed on the wall surface of the concave portion 78 (upper portion of the engine 21) on one coupling surface of the intake manifold 47. As a result, in the water jacket provided on the engine 21 and above the engine, the anode metal
The anode metal 81 is arranged on the side surface of the engine opposite to the side of 71.

Then, the intake manifold 47 is coupled to the mounting seat 75 of the cylinder head 28 by the bolts 49, and is thus located on the other side surface of the upper portion of the engine on the opposite side to the above and in the recess opening to the outside of the upper portion. The anode metal 81 will be provided.

As shown in FIG. 1, the gear case 11 below the extension case 12 is provided with an anode metal 91 for the outside of the case at a position facing above the propeller screw 5.

Engine 21 having a cooling water passage structure having the above configuration
According to the outboard motor equipped with the engine 21, in the engine 21 in which the intake / exhaust to / from the combustion chamber 36 is the cross-flow type, the cooling water passage 56 on the exhaust passage 39 side of the cylinder block 24 (engine
The anode metal 71 is installed in a lower part of 21), and in the cooling water passage 79 on the intake passage 37 side of the cylinder head 28 located on the side surface on the opposite side of the mounting portion of the anode metal 71 in the cylinder periphery ( Anode metal 81 is also installed on the upper part of the engine 21). That is, since the anode metals 71 and 81 are respectively installed in the water jackets on both sides of the peripheral wall surrounding the cylinder 25 within the range upstream of the thermostat 61, a significantly high rust prevention effect can be obtained. it can.

That is, in the water jacket, the engine 21
Because of the two anode metals 71, 81 provided on both side surfaces of the anode metal 71, 81, which are vertically spaced apart from each other, the inner wall portion of the water jacket is located at a short distance from each anode metal 71, 81.

Then, the anode metal 71 is mounted in the cooling water passage 56 by the recess on the exhaust passage 39 side of the cylinder block 24 with the screw 73, and the opening of the recess is closed by the cooling water passage cover 67,
Further, the anode metal 81 is also mounted in the cooling water passage 79 by the recess 76 on the intake passage 37 side of the cylinder head 28 with the screw 83 and the opening of the recess is closed by the intake manifold 47. In comparison with the structure in which anode metal is inserted from the outside into the sand removal hole for molding the water jacket and the hole for holding the core, which is used when casting and molding cylinder heads, there are restrictions on the shape and size of the anode metal. As described above, relatively large anode metals 71 and 81 can be provided in the water jackets on both sides of the cylinder peripheral wall without any restriction on the mounting location.

Therefore, it is possible to contribute to the improvement of the rust-preventing effect and the service life.

In addition, since the cooling water passages 79 and 56 are respectively closed by the recesses that store the anode metals 81 and 71 that utilize the intake manifold 47 and the cooling water passage cover 67, respectively, a lid member dedicated to the anode metal portion is provided. It is not necessary to separately prepare each anode metal, the anode metals 71, 81 can be easily attached, and the shape of each anode metal 71, 81 can be freely selected.

Regarding the engine, the number of cylinders and the specific structure of the cooling water passage are arbitrary, and three or more anode metals (sacrificial electrodes) may be provided as necessary.

(Effects of the Invention) As is apparent from the above, according to the present invention, the water jacket that is opened and closed by the thermostat provided in the upper part of the engine is provided, and the sacrificial electrode is provided within the range upstream of the thermostat of the water jacket. In a water-cooled engine, a water jacket is provided on the cylinder block, and is provided on the cylinder block and a cylinder surrounding portion that surrounds the cylinder circumference.The water jacket is connected to the cylinder surrounding portion and is provided outside the cylinder surrounding portion. An outer portion provided on the cylinder head, the combustion chamber surrounding portion communicating with the cylinder surrounding portion, and the outer portion provided on the cylinder head outside the combustion chamber surrounding portion. Block, outer portion of the cylinder surrounding portion of the cylinder head, combustion chamber surrounding portion The respective outer portions, a recess which opens the cylinder block, outside the cylinder head,
A lid member for closing each of the open concave portions is provided, and a sacrificial electrode is provided in each cooling water passage surrounded by the lid member and the concave portions. Side, the sacrificial electrode is disposed in the lower portion of the engine, and the other of the sacrificial electrodes is disposed in the upper portion of the engine on the other side opposite to the sacrificial electrode of the engine. Without being restricted by the above, the anode metal forming the relatively large sacrificial electrode can be provided in the water jackets on both sides of the cylinder peripheral wall.

Further, the present invention can provide a relatively large anode metal capable of increasing the rust prevention effect, can set the shape of the anode metal excellent in the rust prevention effect in terms of shape, and in the water jacket With the anode metals provided on both side surfaces of the engine and vertically separated from each other, it is possible to obtain the anode metal that is disposed in the engine water jacket and has excellent rust prevention effect.

Further, according to the present invention, each of the recesses opened to the outside is formed such that one is a recess on the exhaust passage side provided on the cylinder block side,
The cooling water passage of the cylinder block including the recess is closed by a cooling water cover, and the other is a recess on the intake passage side provided on the cylinder head side, and the cooling water passage of the cylinder head including the recess is closed by an intake manifold. I did so,
It is not necessary to prepare a dedicated lid member for accommodating and closing the sacrificial electrode, and the recess provided with the sacrificial electrode can be closed using the cooling water passage cover and the existing intake manifold.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an outboard motor with an engine cover portion cut away as an example to which the present invention is applied, FIG. 2 is a cross-sectional plan view of an essential part of an engine, and FIG. 3 is the opposite side of FIG. Fig. 4 is a side view of the engine head seen from the side of the cylinder head seen from the intake manifold connecting surface, Fig. 5 is a front view showing the cylinder head connecting surface of the intake manifold, and Fig. 6 is a cylinder block. FIG. 7 is a side view of a main part as viewed from the cooling water passage cover coupling surface, and FIG. 7 is a front view showing the cylinder block coupling surface of the cooling water passage cover. In the drawing, 21 is an engine, 22 is a crankshaft, 24 is a cylinder block, 25 is a cylinder, 28 is a cylinder head,
36 is a combustion chamber, 37 is an intake passage, 38 is an exhaust passage, 47 is an intake manifold that is a lid member, 55 is a cylinder surrounding portion, 56 is an outer portion, 57 is a combustion chamber surrounding portion, 61 is a thermostat,
67 is a cooling water passage cover which is a lid member, 71 and 81 are anode metals which are sacrificial electrodes, and 79 is an outer portion.

Claims (3)

(57) [Claims] 1. A water-cooled engine having a water jacket opened and closed by a thermostat provided on an upper part of the engine, wherein a sacrificial electrode is provided in a region upstream of the thermostat of the water jacket. A cylinder surrounding portion provided on the cylinder block so as to surround the cylinder circumference; and an outer portion provided on the cylinder block, communicating with the cylinder surrounding portion, and provided outside the cylinder surrounding portion. A combustion chamber surrounding portion provided on the cylinder head and communicating with the cylinder surrounding portion, and an outer portion provided on the cylinder head outside the combustion chamber surrounding portion, a cylinder block, and a cylinder The outer portion of the cylinder surrounding portion and the outer portion of the combustion chamber surrounding portion of the head, respectively. Is provided with a concave portion that is opened to the outside of the cylinder block and the cylinder head, and a lid member that closes each of the open concave portions is provided, and inside each cooling water passage surrounded by each lid member and each concave portion. In the sacrificial electrode, one of the sacrificial electrodes is one side of the engine,
A water-cooled engine, wherein the water-cooled engine is disposed in a lower portion of the engine, and the other of the sacrificial electrodes is disposed in the upper portion of the engine on the other side of the engine opposite to the sacrificial electrode. 2. One of the recesses opened to the outside is a recess on the exhaust passage side provided on the cylinder block side, and the cooling water passage of the cylinder block including the recess is closed by a cooling water cover, 2. The water-cooled type according to claim 1, wherein the other is a recess on the intake passage side provided on the cylinder head side, and the cooling water passage of the cylinder head including the recess is closed by an intake manifold. engine. 3. The water-cooled engine according to claim 1, wherein the crankshaft of the water-cooled engine is placed substantially vertically.