JP4006962B2 - Secondary air supply device for outboard motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an outboard motor used for, for example, a motor boat, and more particularly to a secondary air supply device for an outboard motor for purifying exhaust gas.
[0002]
[Prior art]
As an outboard motor equipped with a secondary air supply device, there is one disclosed in JP-A-8-32365. FIG. 9 is a longitudinal sectional view of an outboard motor provided with a conventional secondary air supply device, and FIG. 10 is a perspective view showing the entire configuration of the secondary air supply device.
[0003]
The outboard motor shown in FIG. 9 mounts a four-cycle multi-cylinder water-cooled engine (hereinafter simply referred to as an engine) 2 on a mount case 3 with the cylinder head 1 oriented sideways and the crankshaft (not shown) oriented vertically. The engine 2 is covered and fixed with an engine cover 4 and an undercase 5.
[0004]
6 is a secondary air supply device for supplying fresh air to the exhaust upstream side of the catalytic converter 7 for purifying exhaust gas generated during engine operation, which is screwed to the undercase 5 via a bracket 8. A secondary air supply device main body 10 in which a check valve (not shown) is accommodated in the metal valve box 9 formed, a primary tube 11 connected to the inlet side of the secondary air supply device main body 10, and an outlet side The secondary tube 12 is configured to be connected.
[0005]
An intake silencer 13 shown in FIG. 10 is arranged on the side surface of the engine 2 (the back side in the drawing), and a fresh air intake port 11a of the primary tube 11 is connected to a top plate 13a of the intake silencer 13. ing.
[0006]
The secondary tube 12 penetrates the undercase 5 from top to bottom and is connected to a horizontally bent metal connecting pipe 14 and is inserted into the side surface of the mount case 3 through the connecting pipe 14. The fresh air can be supplied to the exhaust passage 15 provided in the mount case 3 and extending vertically.
[0007]
[Problems to be solved by the invention]
However, as is apparent from FIGS. 9 and 10, the conventional secondary air supply apparatus needs to install a valve box 9 that accommodates a check valve (not shown) in the undercase 5. The piping lengths of the secondary tubes 11 and 12 are long and are complicatedly routed so as to bypass the engine 2.
[0008]
Moreover, since the metal valve box 9 is disposed close to the side of the engine 2, the metal valve box 9 becomes hot due to the radiant heat from the engine 2, but with the engine cover 4 opened, the outboard motor It is easy for the person who uses the product to touch, so that it is easy to touch carelessly.
[0009]
Further, in the above conventional outboard motor, there is no room for installing the secondary tube 12 or the valve box 9 near the exhaust port (not shown) of the engine 2, and therefore, a new part is provided relatively far from the exhaust port. Since the air is supplied, there is a disadvantage that the exhaust gas purification efficiency is lowered.
[0010]
Accordingly, the present invention improves the purification efficiency by allowing fresh air to be supplied to the exhaust gas at a position close to the exhaust port of the engine, and also allows a person who uses the outboard motor to contact the secondary air supply device main body. It is an object of the present invention to provide a secondary air supply device for an outboard motor that can be prevented.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
That is, the present invention covers the engine fixed on the upper part of the engine holder with the engine cover, and connects the drive shaft housing and the gear case to the lower part of the engine holder in order, and exhausts the engine holder, the drive shaft housing and the gear case into the exhaust. An outboard motor having an exhaust passage for gas, wherein the secondary air supply device of the outboard motor supplies fresh air as secondary air to the exhaust passage.
In the engine, a cylinder block protruding rearward from the crankcase is fastened on the oil pan, a cylinder head is fastened to the rear of the cylinder block, and an exhaust manifold communicating with the exhaust port is provided on the lower surface of the cylinder head. while being projected downward, a margin space surrounded by the front side of the lower side surface and the exhaust manifold side and the cylinder block after the engine holder and the oil pan is partitioned and formed,
Since at least a part of the secondary air supply device for supplying fresh air to the exhaust passage is disposed in the spare space, it becomes possible to supply fresh air to the exhaust gas at a position close to the exhaust port of the engine. Accordingly, the exhaust gas purification efficiency can be improved and the person using the outboard motor can be prevented from coming into contact with the secondary air supply device.
[0012]
In the present invention , the secondary air supply device has a fresh air supply hole for introducing fresh air into the exhaust passage, and the fresh air supply hole opens toward the marginal space. it can be.
[0013]
In the present invention , the secondary air supply device is opened and closed by exhaust pulsation, and a secondary air supply device body having a reed valve that introduces fresh air when the exhaust passage has a negative pressure, and the reed valve has fresh air. The reed valve can be disposed on the exhaust passage side facing the fresh air supply hole .
[0014]
In the present invention, the secondary air supply apparatus, and opened and closed by exhaust pulsation, and the secondary air supplying device body accommodating a reed valve in the valve box for introducing fresh air when the exhaust passage negative pressure, constitute a fresh air supply path downstream for supplying fresh air discharged from the upstream side fresh air supply passage and the valve box for supplying fresh air to the reed valve into the exhaust passage the fresh air supply path downstream may be connected to the fresh air supply hole is opened toward the spare area.
[0015]
In the above, the structure which connected the fresh air intake of the fresh air supply path to the intake silencer attached to the intake manifold of the cylinder head is preferable.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a left side view of a part of an outboard motor provided with a secondary air supply device according to an embodiment. The left side is the front side (the hull side) and the right side is the rear side. 2 is a partially enlarged view of a main part of an outboard motor shown through a single-cylinder four-cycle engine, FIG. 3 is a detailed view showing the main part further enlarged, and FIG. It is a top view of the state which removed the upper cover of the engine cover.
[0017]
In the outboard motor A, for example, a single-cylinder four-cycle engine (hereinafter simply referred to as an engine) 17 covered with an engine cover 16 is fixed to an upper portion of an engine holder 18, and a drive shaft housing 19 and a gear case are provided below the engine holder 18. 20 in order.
[0018]
The engine 17 is a cylinder block 24 in which a cylinder 24a is integrally protruded from the crankcase 24c toward the side (rear side) on an oil pan 22 in which the crankshaft 21 shown in FIGS. It is the thing of the structure which fastened.
[0019]
The engine cover 16 has an upper and lower divided structure composed of an upper cover 16a and a lower cover 16b, which are formed in a substantially elliptical shape that is long in the front-rear direction in plan view, as shown in FIG. .
[0020]
A longitudinally long fuel tank 25 is disposed on the front side (front side) of the engine 17, and is fixed to the front side wall 24 b of the crankcase 24 c of the engine 17.
[0021]
At the lower end of the crankshaft 21 of the engine 17, a drive shaft 26 that penetrates the oil pan 22, is inserted into the drive shaft housing 19, and reaches the gear case 20 is integrally connected to the rotation. .
[0022]
In the gear case 20, a propeller shaft 27 is pivotally supported in the front-rear (horizontal) direction, and a screw propeller 28 is provided integrally with the rear end portion of the propeller shaft 27.
[0023]
A bevel gear mechanism 29 and a clutch shifter (not shown) are disposed at a portion where the lower end of the drive shaft 26 reaches the propeller shaft 27, and the rotation of the drive shaft 26 in the horizontal plane is performed via the bevel gear mechanism 29. It is converted into rotation in the vertical plane of the propeller shaft 27 and transmitted. By this power transmission, the screw propeller 28 is rotationally driven to generate a propulsive force.
[0024]
In addition, a clutch shifter (not shown in detail) provided in the bevel gear mechanism 29 allows the rotation of the drive shaft 26 that always rotates in a certain direction to be switched between forward and reverse directions and can be transmitted to the propeller shaft 27. Forward or reverse of the outboard motor (hull) A can be selected.
[0025]
A clamp bracket 30 for fixing the outboard motor A to the stern is pivotally supported on the upper portion of the drive shaft housing 19 via a swivel shaft (not shown).
Accordingly, the outboard motor A rotates to the left and right about the swivel shaft according to the steering operation of the handle 31 attached to the upper part of the drive shaft housing 19, thereby steering the hull (not shown).
[0026]
As shown in FIGS. 2 and 3, the cylinder head 23 of the engine 17 has an intake port 23a communicating with a combustion chamber c formed between the piston 24d and the exhaust port 23b on the lower side. Are provided, and an intake valve 32 and an exhaust valve 33 are provided in the intake port 23a and the exhaust port 23b, respectively.
[0027]
The intake valve 32 is driven to open and close in accordance with the rotation of an intake camshaft (not shown), and the intake port 23a and the combustion chamber c are communicated / blocked. The exhaust valve 33 is driven to open and close in accordance with the rotation of an exhaust camshaft (not shown) so that the exhaust port 23b and the combustion chamber c are communicated / blocked.
[0028]
An exhaust manifold 34 that communicates with the exhaust port 23b is projected downward on the middle part of the lower side of the cylinder head 23, and an intake manifold 35 is projected upward on the upper side.
[0029]
That is, the rear side surface 22a of the oil pan 22, the lower side surface 24a ' of the cylinder 24a, and the front side surface 34a of the exhaust manifold 34 define a marginal space α having a substantially vertical rectangular shape in side view below the cylinder 24a.
In the present embodiment, a secondary air supply device main body forming a part of the secondary air supply device B , the details of which will be described later, is disposed in the margin space α.
[0030]
As shown in FIG. 4, a carburetor 36 and an intake silencer 37 that are protruded obliquely forward are sequentially connected to the intake manifold 35 of the cylinder head 23.
[0031]
The intake silencer 37 is formed in a substantially vertical rectangular parallelepiped shape, and a pipe connection port 37a for connecting a fresh air intake port (one end) 38a of a supply pipe 38, which will be described later, is formed at the lower end of the intake silencer 37 so as to protrude. Has been. The pipe connection port 37a faces a position where it does not overlap with the cylinder 24a in plan view, in other words, a space on one side of the cylinder 24a.
[0032]
The engine 17 described above is placed and fastened on the engine holder 18 via an exhaust passage cover 39.
The engine holder 18 is formed in a length extending from the rear side surface 34b of the exhaust manifold 34 to the front side surface 22b of the oil pan 22, and is a plane that opens the entire top surface and opens a discharge port 18a toward the front side of the bottom. It is a substantially rectangular one.
[0033]
The exhaust passage cover 39 has an outer shape that matches the contour of the upper surface opening 18b of the engine holder 18, and a through hole 39a that is substantially the same shape as the opening 34c is formed in a portion facing the opening 34c of the exhaust manifold 34. It is. By covering the upper surface opening 18b of the engine holder 18 with the exhaust passage cover 39, an in-holder exhaust passage β1 is defined in the engine holder 18.
That is, the exhaust gas discharged from the exhaust manifold 34 is guided to the gear case 20 through the exhaust passage β1 in the holder and the exhaust passage (not shown) in the drive shaft housing 19 and then discharged to the outside. Yes.
[0034]
The secondary air supply device B according to one embodiment of the present invention is formed of a reed valve 40 which is a main body of the secondary air supply device, and heat resistant rubber for supplying fresh air to the exhaust manifold 34, that is, the exhaust passage. And a supply pipe 38 which is a fresh air supply path.
[0035]
In the present embodiment, the reed valve 40 that is the main body of the secondary air supply device is disposed in the vicinity of the lower end opening of the front side surface 34 a of the exhaust manifold 34.
The vicinity of the lower end opening of the front side surface 34a of the exhaust manifold 34 is formed to have a thickness slightly protruding forward over a required range, and a fresh air supply hole 41 having a required inner diameter penetrates the thick portion 34d. It is installed.
[0036]
A step portion 41a having a diameter slightly larger than the inner diameter of the fresh air supply hole 41 is formed in the outer opening of the fresh air supply hole 41, and a connecting pipe 42 having an L shape in side view is formed in the step portion 41a. And the other end of the supply pipe 38 is connected to the connecting pipe 42.
Further, the reed valve 40 is disposed in the inner opening 41b of the fresh air supply hole 41 so as to be opposed thereto.
[0037]
The reed valve 40 includes an open / close valve 43 that elastically opens and closes the inner opening 41b of the fresh air supply hole 41 in response to the exhaust pulsation of the exhaust gas discharged from the exhaust manifold 34, and the opening degree of the open / close valve 43. The stopper 44 is bent at a required angle for regulating the opening and closing of the opening / closing valve 43 between the inner wall surface of the exhaust manifold 34 and the stopper 44. Then, the upstream end in the exhaust gas flow direction is superposed by, for example, bolts or the like.
[0038]
The operation of the secondary air supply device B having the above configuration will be described with reference to FIGS.
When the exhaust valve 33 is opened, the pressure in the exhaust manifold 34, that is, the exhaust passage becomes positive. In this state, the on-off valve 43 is in close contact with the inner wall surface, thereby closing the inner opening 41b of the fresh air supply hole 41. In this closed state, fresh air is not supplied from the fresh air supply hole 41 into the exhaust passage.
[0039]
When the exhaust valve 33 is closed, the pressure in the exhaust passage becomes negative. In this state, the on-off valve 43 is elastically deformed so as to be separated from the inner wall surface, whereby the inner opening 41b of the fresh air supply hole 41 is opened and sucked from the intake silencer 37 described above. Fresh air is supplied into the exhaust passage through the fresh air supply hole 41. As a result, fresh air can be supplied to the exhaust gas at a position close to the exhaust port 23b of the engine 17, and the purification efficiency can be improved.
[0040]
Next, another example of the secondary air supply device main body will be described with reference to FIG.
The secondary air supply device main body according to this other example is a reed valve 40 'having the same configuration as described above.
[0041]
A fresh air supply hole 45 having a required inner diameter is formed through the upper and lower surfaces of the exhaust passage cover 39 facing the marginal space α.
A union 46 protrudes from the upper opening 45 a of the fresh air supply hole 45, and the lower end portion of the supply pipe 38 is connected to the union 46. In addition, a reed valve 40 ′ is disposed in the lower opening 45 b of the fresh air supply hole 45 so as to face it.
[0042]
The reed valve 40 ′ is an open / close valve 43 ′ that elastically opens and closes the lower opening 45 b of the fresh air supply hole 45 in response to the exhaust pulsation of the exhaust gas discharged from the exhaust manifold 34. Stopper 44 'bent at a required angle for restricting the opening of', and in the state where the open / close valve 43 'is interposed between the lower surface of the exhaust passage cover 39 and the stopper 44', One end portion of the on-off valve 43 ', in other words, the upstream end portion in the exhaust gas flow direction is superposed by, for example, bolts or the like. That is, the reed valve 40 ′ is disposed in the in-holder exhaust passage β 1 in the engine holder 18.
[0043]
The operation of the secondary air supply device using such a reed valve 40 'will be described.
When the exhaust valve 35 is opened, the pressure in the exhaust passage becomes positive. In this state, the on-off valve 43 ′ is in close contact with the lower surface of the exhaust passage cover 39, thereby closing the lower opening 45 b of the fresh air supply hole 45. In this closed state, fresh air is not supplied from the fresh air supply hole 45 into the exhaust passage.
[0044]
When the exhaust valve 35 is closed, the pressure in the exhaust passage becomes negative. In this state, the on-off valve 43 ′ is elastically deformed so as to be separated from the lower surface of the exhaust passage cover 39, and thereby the lower opening 45 b of the fresh air supply hole 45 is opened, and the intake silencer 37 The sucked fresh air is supplied into the exhaust passage through the fresh air supply hole 45.
[0045]
A modification of the secondary air supply device main body will be described with reference to FIGS.
The secondary air supply device A ′ according to the modified example includes a valve body 47 that is a main body of the secondary air supply device and an upstream formed by heat-resistant rubber that is a new air supply passage for supplying new air to the exhaust passage, And supply pipes 48 and 49 on the downstream side.
[0046]
The valve body 47 is fixed to the outer side surface of the oil pan 22, and it has an intermediate plate 51 having the same contour as the opening in the shallow body 50 opened on one side surface. The outer plate 52 is superposed and fixed on the outer surface of the plate 51, thereby forming vacant spaces γ 1 and γ 2 on both sides of the intermediate plate 51.
[0047]
A connecting pipe 53 projects from the end face facing the vacant space γ1 defined by the intermediate plate 51 and the outer plate 52, and faces the vacant space γ2 defined in the container 50 by the intermediate plate 51. A connecting pipe 54 projects from the end face.
[0048]
The supply pipe 48 has a fresh air intake port (one end) 48a connected to the connection pipe 37a of the intake silencer 37 and the other end connected to the connection pipe 53 of the valve body 47. It is led out from the connecting pipe 37a of the line 37 substantially vertically downward.
[0049]
The vicinity of the lower end opening of the front side surface 34a of the exhaust manifold 34 is formed to protrude slightly thicker forward over a required range, and a fresh air supply hole 55 having a required inner diameter penetrates the thick portion 34d. Has been.
[0050]
A step portion 55a having a diameter slightly larger than the inner diameter of the fresh air supply hole 55 is formed in the outer opening of the fresh air supply hole 55. A connection pipe 56 having an L-shape in side view is formed in the step portion 55a. Is inserted and fixed.
[0051]
One end of the supply pipe 49 is connected to the connecting pipe 54 of the valve body 47 and the other end is connected to the connecting pipe 56. The supply pipe 49 is disposed in the marginal space α so as to be substantially horizontal in a side view. Has been.
[0052]
The intermediate plate 51 is formed with a fresh air circulation hole 51a at the center thereof, and a reed valve 40 ″ is disposed to face the fresh air circulation hole 51a.
[0053]
The reed valve 40 ″ is disposed on the vacant γ2 side, in other words, in the vessel body 50, which elastically moves the fresh air circulation hole 51a in response to the exhaust pulsation of the exhaust gas discharged from the exhaust manifold 34. And an opening / closing valve 43 ″ that opens and closes, and a stopper 44 ″ that is bent at a required angle that regulates the opening of the opening / closing valve 43 ″. The opening / closing valve 43 ″ is provided between the side surface of the intermediate plate 51 and the stopper 44 ″. In a state where “is inserted”, the stopper 44 ″ and one end portion of the on-off valve 43 ″ are superposed by, for example, bolts or the like.
[0054]
Note that the present invention is not limited to the above-described embodiment, and the following modifications can be made.
In FIG. 8, the example in which the valve body 47 which is the main body of the secondary air supply device is fixed to the outer surface of the oil pan 22 has been described, but the valve body 47 may be disposed in the marginal space α. .
[0055]
【The invention's effect】
According to the first to fifth aspects of the present invention, a marginal space is formed below a cylinder projecting sideways in the crankcase of the engine, and exhaust gas exhausted from the engine is exhausted in the marginal space. Since at least a part of the secondary air supply device for supplying fresh air to the passage is disposed, fresh air can be supplied to the exhaust gas at a position close to the exhaust port of the engine.
Therefore, the purification efficiency of the exhaust gas can be improved and at least a part of the secondary air supply device is disposed in the marginal space, so that contact with the secondary air supply device can be prevented.
[0056]
In addition to the above-mentioned common effects obtained by the inventions according to claims 1 to 5, according to the inventions described in the claims, the following effects can be obtained.
According to the invention of claim 4, the secondary air supply device is opened and closed by exhaust pulsation, and the secondary air supply device in which the reed valve for introducing fresh air when the exhaust passage is negative pressure is accommodated in the valve box. a body and, a fresh air supply path downstream of the to be supplied to the exhaust passage of the fresh air discharged from the upstream side fresh air supply passage and the valve box for supplying fresh air to the reed valve and which, since the fresh air supply path on the downstream side are connected to the fresh air supply hole which is open toward the inside the spare area, the spare area is enough to even provided a secondary air supplying device body Even when it is not wide, fresh air can be supplied to the position near the exhaust port of the engine.
[0057]
According to the fifth aspect of the present invention, the intake silencer is attached to the intake manifold of the cylinder head, and the intake air of the fresh air supply path is connected to the intake silencer. Etc. can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a left side view of a part of an outboard motor provided with an embodiment of a secondary air supply device of the present invention.
FIG. 2 is a partially enlarged view of the main part of the outboard motor shown through a single cylinder four-cycle engine.
FIG. 3 is a detailed view showing the main part further enlarged.
FIG. 4 is a plan view of the outboard motor with the upper cover of the engine cover removed.
FIG. 5 is a partial side view showing an operating state of the reed valve, showing a state in which the on-off valve is closed.
FIG. 6 is a partial side view showing an operating state of the reed valve, showing a state in which the on-off valve is open.
FIG. 7 is a partial side view showing another example of the secondary air supply device main body.
8A is a partial side view centering on an engine provided with a modified example of the secondary air supply device, and FIG. 8B is a cross-sectional view taken along line II of the main body of the secondary air supply device shown in FIG. It is sectional drawing which follows.
FIG. 9 is a longitudinal sectional view of an outboard motor provided with a conventional secondary air supply device.
FIG. 10 is a perspective view showing the overall configuration of the secondary air supply device.
[Explanation of symbols]
16 Engine cover 17 Engine 18 Engine holder
18a Discharge port 19 Drive shaft housing 20 Gear case
22 Oil pan
23 Cylinder head 23b Exhaust port 24 Cylinder block 24a Cylinder 24c Crankcase 34 Exhaust manifold 35 Intake manifold 37 Intake silencer 37a Fresh air intake ports 38, 48, 49 Supply pipes 40, 40 ', 40 "which are fresh air supply passages
41 Hole for fresh air supply
43 On-off valve
44 Stopper
A engine
B, B 'secondary air supply device α allowance space β1 exhaust passage in engine holder

Claims (5)

The engine fixed to the upper part of the engine holder is covered with an engine cover, and a drive shaft housing and a gear case are sequentially connected to the lower part of the engine holder, and an exhaust gas exhaust passage is formed in the engine holder, the drive shaft housing and the gear case. In the secondary air supply apparatus for an outboard motor that supplies fresh air as secondary air to the exhaust passage thereof,
In the engine, a cylinder block protruding rearward from the crankcase is fastened on the oil pan, a cylinder head is fastened to the rear of the cylinder block, and an exhaust manifold communicating with the exhaust port is provided on the lower surface of the cylinder head. while being projected downward, a margin space surrounded by the front side of the lower side surface and the exhaust manifold side and the cylinder block after the engine holder and the oil pan is partitioned and formed,
A secondary air supply device for an outboard motor, wherein at least a part of a secondary air supply device for supplying fresh air to the exhaust passage is disposed in the spare space. The secondary air supply device has a fresh air supply hole for introducing fresh air into the exhaust passage, and the fresh air supply hole is opened toward the marginal space. The secondary air supply device for an outboard motor according to claim 1, wherein The secondary air supply device is opened and closed by exhaust pulsation, and a secondary air supply device main body having a reed valve for introducing fresh air when the exhaust passage has a negative pressure, and for supplying fresh air to the reed valve. The outboard motor secondary according to claim 2, further comprising a fresh air supply path, wherein the reed valve is disposed on an exhaust passage side facing the fresh air supply hole. Air supply device. The secondary air supply device is opened and closed by exhaust pulsation, and a reed valve for introducing fresh air when the exhaust passage is negative pressure is housed in a valve box, and fresh air is supplied to the reed valve. It has a fresh air supply path downstream of the to be supplied to the exhaust passage of the fresh air discharged from the upstream side fresh air supply passage and the valve box for supplying fresh air supply passage downstream the secondary air supply system for an outboard motor according to claim 2, characterized in that it is connected to the fresh air supply hole is opened toward the spare area. Above the intake manifold of the cylinder head is attached an intake silencer, the outboard motor of claim 1, 2, 3 or 4, wherein connecting the fresh air intake of fresh air supply passage to the intake silencer 2 Secondary air supply device.

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