JP4017130B2 - Corrosion prevention device for outboard engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a corrosion prevention device in a 4-cycle multi-cylinder engine for an outboard motor.
[0002]
[Prior art]
In an outboard engine, the engine body may be cooled with seawater. Therefore, an anode (pseudo-control electrode) made of a material having a higher ionization tendency than the material of the engine body is provided in the cooling water passage of the cylinder head. By ionizing the engine body, corrosion of the engine body is prevented.
[0003]
[Problems to be solved by the invention]
By the way, in a 4-cycle multi-cylinder engine for an outboard motor, each cylinder is placed in the vertical direction in a horizontally placed state, and the outlet of the exhaust port is formed at the mating surface of the cylinder head and the cylinder body and connected to the exhaust port. Since the exhaust passage penetrates the cylinder body in the vertical direction, cooling around the exhaust passage is a big problem. Therefore, the present applicant has filed a system in which the cooling water passages of the cylinder head are separately provided in two systems, cooling around the exhaust passage is prioritized, and then the combustion chamber is cooled. However, in this system, when the anode is provided in the cooling water passage around the conventional combustion chamber, the cooling water passage around the combustion chamber and the exhaust passage are configured as separate passages. The problem is that corrosion will occur.
[0004]
The present invention solves the above problem, and in an engine in which engine body cooling water passages are separately provided in two systems, corrosion of the engine for an outboard motor capable of effectively preventing corrosion of the engine body. An object is to provide a prevention device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the corrosion prevention device for an outboard engine according to claim 1 includes cooling water passages P and S around the exhaust passage and around the combustion chamber, which are separately formed in the cylinder head 5c, and the cylinder. A cooling water passage Q and T around the exhaust passage and the cylinders separately formed in the body 5b, and a cooling water passage inlet I, a cylinder head exhaust passage, a cylinder body exhaust passage formed in the lower part of the cylinder body 5b An engine for an outboard motor that supplies cooling water in the order of the periphery, the cylinder head combustion chamber, and the cylinder body and the cylinder, and the first anode 50 is attached to a cooling water passage inlet I formed in the lower portion of the cylinder body 5b. In addition, the second anode 51 is provided in one of the cooling water passages T and S around the combustion chamber of the cylinder head or around the cylinder of the cylinder body. Characterized in that the wearing, invention of claim 2, characterized in that in claim 1, mounted by using a sand removing holes 52 for casting the second anode 51 formed in the cylinder head 5c According to a third aspect of the present invention, in the first aspect, the anode includes a cover member 51a and an electrode member 51 fixed to the cover member by a seal bolt 51b, and the cover member 51a and the electrode member 51c are provided. The invention is characterized in that it is sealed from the engine side by a sealing member 53. The invention according to claim 4 is the invention according to claim 1, wherein the anode includes a cover member 51a and an electrode member 51c fixed in the cover member by a stud 51e. The cover member 51a and the electrode member 51c are sealed from the engine side by the seal member 53. In addition, the number added to the said structure contrasts with drawing in order to make an understanding of this invention easy, and this invention is not limited at all by this.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show one embodiment of a four-cycle engine according to the present invention. FIG. 1 is a side view, FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a plan view of FIG. FIG. 5 is a cross-sectional view taken in the direction of the arrow along the line XX in FIG.
[0007]
1 to 5, an engine 1 is, for example, a four-cylinder four-cycle engine for an outboard motor, and the outer periphery is covered with a bottom cowling 2 and an upper cowling 3. The engine body 5 includes a crankcase 5a, a cylinder body 5b, and a cylinder head 5c, and a cam cap 5d and a head cover 5e are fixed to the cylinder head 5c. In the cylinder body 5b, four cylinders 6 are arranged in the vertical direction in a horizontally placed state, and in the cylinder body 5b and the crankcase 5a, a crankshaft 7 is arranged in a vertically placed state. A piston 9 slidably fitted to the crankshaft 7 is connected. The crankshaft 7 protrudes from the upper surface of the engine body 5, the flywheel 10 is fixed to the upper end, and the drive gear 11 is fixed to the lower part.
[0008]
As shown in FIGS. 2 and 5, the cylinder head 5 c is provided with two intake valves 12, an exhaust valve 13, and a spark plug 15 so as to face each cylinder 6. In order to open and close the intake valve 12 and the exhaust valve 13, the two camshafts 16 and 17 having cams are arranged in a vertical position, and are rotatable to the cylinder head 5c by a plurality of cam caps 5d. It is supported. As shown in FIG. 5, an intake port 19 and an exhaust port 20 are formed in the cylinder head 5 c, and the intake port 19 is connected to an intake manifold 22 having a carburetor 21.
[0009]
On the upper ends of the camshafts 16 and 17, hook-shaped driven gears 23 and 24 are fixed with bolts 25 with the hooks facing downward, and a drive belt 26 is stretched between the driven gears 23 and 24 and the drive gear 11. . Further, as shown in FIG. 3, a belt tensioner 27 is attached on the cylinder body 5b. A cover 31 is provided so as to cover the flywheel 10 and the driven gears 23 and 24. A thermostat 32 is provided on the cylinder head 5c.
[0010]
As shown in FIG. 5, an exhaust passage 33 connected to the exhaust port 20 is formed in the cylinder body 5b. A first cooling water passage P around the exhaust port 20 and a second cooling water passage S around the combustion chamber are separately formed in the cylinder head 5c, and cooling water around the exhaust passage 33 is formed in the cylinder body 5b. The passages Q and U and the cooling water passage T around the cylinder are formed separately. A part of the cooling water passage Q around the exhaust passage 33 and U are formed between the cylinder body 5b and the cover member 35, and the thermostat 32 and the cooling water passage U are connected by a tube 36 (FIGS. 1 and 3). ing.
[0011]
Next, an embodiment of the corrosion prevention apparatus for an outboard engine of the present invention will be described. FIG. 6 is a schematic diagram showing the configuration of the cooling water system, FIG. 7 shows the cylinder body, FIG. (A) is a front view, FIG. (B) is a view of FIG. FIG. 2A is a cross-sectional view, and FIGS. 2B and 2C are enlarged cross-sectional views.
[0012]
5-7, the seawater sucked by the cooling water pump 37 driven by the drive shaft enters the lower inlet I of the cylinder body 5b through the cooling water pipe 39, and the cooling water around the exhaust port 20 of the cylinder head 5c. The cooling water passage S and the cylinder around the combustion chamber of the cylinder head 5c pass through the cooling water passage Q around the exhaust passage 33 of the cylinder body 5b through the passage P, and further through the cooling water passage R formed in the cylinder body 5b. The water passes through the cooling water passage T around the cylinder of the body 5b, and further passes through the thermostat 32 and the tube 36, and then passes through the cooling water passage U around the exhaust passage 33 of the cylinder body 5b.
[0013]
Although only the main cooling water passage is shown in FIG. 6, the cooling water passages P and Q around the exhaust passage communicate with each other in a narrow passage between the cylinder head 5c and the cylinder body 5b in each cylinder 6. Similarly, the cooling water passage S around the combustion chamber of the cylinder head 5 c and the cooling water passage T around the cylinder of the cylinder body 5 b are completely communicated with each other in each cylinder 6.
[0014]
One anode 50 is mounted near the lower inlet I of the cylinder body 5b, and two anodes 51 are mounted in the cooling water passage S around the combustion chamber of the cylinder head 5b. The position of the anode 50 may be anywhere in the cooling water passages P and Q because the cooling water passages P and Q around the exhaust passage are communicated as described above, but ions flow downstream. It is preferable to mount the cylinder body 5b on the upstream side as much as possible toward the lower inlet I of the cylinder body 5b. With the above configuration, in the engine in which the cooling water passages of the cylinder head 5c are separately provided in the two systems (P, S), corrosion of the engine body can be prevented.
[0015]
As shown in FIGS. 1 and 4, the anode 50 is mounted through the cover member 35. The mounting structure is the same as that of the anode 51 described below. As shown in FIG. 8, the anode 51 is mounted using a sanding hole 52 for casting in a recess between the two camshafts 16 and 17 of the cylinder head 5c, and can be exchanged from the outside. . In the anode 51, the electrode member 51c is screw-sealed to the aluminum cover member 51a with a seal bolt 51b so that seawater does not leak outside even if the electrode member 51c is removed. The electrode member 51c is inserted into the sand removal hole 52, and the cover member 51a is fastened with a bolt 51d (FIG. 4).
[0016]
A step 52a is formed in the sand removal hole 52, and a seal member 53 made of rubber or the like is press-fitted into the step 52a. The seal member 53 has a protrusion 53a formed on the inner peripheral surface so that the seal member 53 is pressed at a point A when the electrode member 51c is inserted, and is pressed at points B and C by tightening the cover member 51a. It is comprised so that. As a result, the seawater in the cooling water passage S does not leak to the outside, and the seawater does not enter the contact D between the cover member 51a and the electrode member 51c, and the electrical connection between the electrode member 51c and the cylinder head 5c can be maintained. it can.
[0017]
FIG. 9 is a cross-sectional view showing another example of an anode mounting structure. In this example, the cover member 51a and the electrode member 51 are embedded with studs having screws so that seawater does not leak to the outside even if the electrode member 51c is eliminated.
[0018]
FIG. 10 is a side view of the outboard motor according to the present invention. The outboard motor 101 includes a clamp bracket 103 that is detachably attached to the rear portion of the hull 102, a swivel bracket 106 that is pivotally supported by the clamp bracket 103 via a tilt shaft 105 in the vertical direction, and the swivel bracket. 106, a guide exhaust 107 and an upper case 109 that are supported rotatably in a horizontal direction, a lower case 110 connected to a lower portion of the upper case 109, a propeller 111 attached to the lower case 110, and an upper portion of the upper case 109. A fixed bottom cowling 2, a top cowling 3 attached to the bottom cowling 2, and an engine 1 attached to the guide exhaust 107, so that the power of the engine 1 is transmitted to the propeller 111 via the drive shaft 112. Composing Further, a cooling water pump 113 driven by the drive shaft 112 is provided so that cooling water can be supplied to the lower surface of the engine 1 through the inlet 115 and the cooling water pipe 116.
[0019]
【The invention's effect】
As is apparent from the above description, according to the first and second aspects of the invention, in the engine in which the cooling water passages of the engine body are separately provided in two systems, corrosion of the engine body can be effectively prevented. .
[0020]
Further, according to the invention described in claim 3, the anode can be mounted using the existing holes and can be exchanged from the outside.
[0021]
In addition, according to the fourth and fifth aspects of the present invention, seawater does not leak to the outside, and seawater does not enter the contact point between the cover member and the electrode member, and the electrical connection between the electrode member and the engine body is maintained. Can do.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of a four-cycle engine according to the present invention.
FIG. 2 is a cross-sectional view of FIG.
3 is a plan view of FIG. 1. FIG.
4 is a view as seen from the Y direction in FIG. 1. FIG.
5 is a cross-sectional view taken in the direction of the arrow along the line XX in FIG.
FIG. 6 is a schematic diagram showing a configuration of a cooling water system according to the present invention.
7 shows a cylinder body according to the present invention, in which FIG. (A) is a front view and FIG. (B) is a view of FIG.
FIG. 8 shows an example of an anode mounting structure, in which FIG. (A) is a cross-sectional view, and FIGS. (B) and (C) are enlarged cross-sectional views.
FIG. 9 is a cross-sectional view showing another example of an anode mounting structure.
FIG. 10 is a side view of an outboard motor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 5 ... Engine body, 5b ... Cylinder body, 5c ... Cylinder head 20 ... Exhaust port 33 ... Exhaust passage 50 ... 1st anode 51 ... 2nd anode 51a ... Cover member, 51b ... Seal bolt, 51c ... Electrode member 51d ... Stud 52 ... Sand removal hole 53 ... Seal member

Claims (4)

A cooling water passage around the exhaust passage and around the combustion chamber formed separately in the cylinder head, and a cooling water passage around the exhaust passage and around the cylinder separately formed in the cylinder body, and formed at the lower part of the cylinder body. An engine for an outboard motor that supplies cooling water in the order of cooling water passage inlet, cylinder head exhaust passage, cylinder body exhaust passage, cylinder head combustion chamber, and cylinder body cylinder. A first anode is attached to the formed cooling water passage inlet, and a second anode is attached to either the combustion chamber of the cylinder head or the cooling water passage around the cylinder of the cylinder body. Corrosion prevention device for outboard engine. The corrosion prevention device for an outboard motor according to claim 1, wherein the second anode is mounted using a sanding hole for casting formed in the cylinder head. 2. The outboard according to claim 1, wherein the anode includes a cover member and an electrode member fixed to the cover member by a seal bolt, and the cover member and the electrode member are sealed from the engine side by the seal member. Anti-corrosion device for machine engines. 2. The outboard according to claim 1, wherein the anode includes a cover member and an electrode member fixed in the cover member by a stud, and the cover member and the electrode member are sealed from the engine side by a seal member. Anti-corrosion device for machine engines.

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