JPH0849596A - Four-cycle engine - Google Patents

Abstract

PURPOSE:To simplify the structure of a four-cycle engine suitable to be used for a vehicle or a device supposed to be overturned such as a small gliding boat. CONSTITUTION:An oil pan 34 is arranged below the bottom section of a crank case 29, and their spaces are connected by a communicating hole 31 provided on the bottom section of the crank case 29. The communicating hole 31 is protruded downward from the bottom section of the crank case 29 toward the oil pan 34, and it is formed together with a peripheral wall 30 apart from the side wall of the oil pan 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-cycle engine suitable for small planing boats and the like.

[0002]

2. Description of the Related Art A small-sized planing boat that glides on water as if it were a motorcycle is conventionally equipped with a two-cycle propulsion engine. This is because the two-cycle engine is small and lightweight, and its lubrication method is suitable for the usage of a small planing boat. In other words, the two-cycle engine has oil (lubricating oil) in the crankcase.
Although it is lubricated by a dry sump method that does not store water, the small planing boat is a vehicle that has the characteristic of overturning (overturning) on the water and causing the pilot etc. to enjoy the gliding in each case. A dry sump method in which oil does not flow into the combustion chamber side is preferable.

On the other hand, a normal four-cycle engine uses wet sump lubrication in which oil is stored in the crankcase. Therefore, if it falls, the oil flows into the combustion chamber through the gap between the cylinder and the piston. Will end up. When oil enters the combustion chamber, white smoke is mixed with the exhaust, and in many cases the engine will stop and restart will be difficult. Therefore, the conventional 4-cycle engine has not been used for small planing boats. There wasn't.

Incidentally, as an example in which a two-cycle engine is mounted on a small planing boat, for example, an actual Kaihei 3-6115 is used.
There is No. 2 publication.

[0005]

In recent years, from the viewpoint of preventing noise and air pollution, the possibility of using a 4-cycle engine for small-sized planing boats has begun to be examined.

However, in order to use the 4-cycle engine in a small planing boat or the like, it is necessary to eliminate the above-mentioned inconvenience regarding oil in the case of tipping. That is, if the conventional four-stroke engine of the wet sump system is used as it is for a small planing boat, oil will flow into the combustion chamber from the inside of the crankcase when it falls. However, if the four-stroke engine is a dry sump system, the structure will be considerably complicated. Since the dry sump system does not store oil in the crankcase, an oil tank is installed separately, and a lubricating oil recovery pump that sucks oil from the crankcase and sends it to that tank is installed, and then from that tank to each part. This is because it is necessary to construct a lubrication system (filter, pressure pump, piping, etc.) for supplying oil. Unlike the 2-cycle engine, which is inevitably a dry sump due to the essential feature of pre-charging the intake air-fuel mixture in the crankcase, the 4-stroke engine, which is not originally simple in structure, has no special inevitability. It is therefore extremely disadvantageous in practice.

An object of the present invention is to provide a four-cycle engine suitable for use in a vehicle / device which is supposed to fall over such as a small planing boat, and which is of a wet sump system which does not complicate the structure. That is.

[0008]

In the four-stroke engine of the present invention, a) an oil pan is arranged further below the bottom of the crankcase. (Of course in an engine, the oil pan is a closed type, and It is not a mere dish-shaped object apart from each other), and the spaces inside the two are connected by a communication hole provided in the bottom of the crankcase, and b) the communication hole is projected downward from the bottom of the crankcase toward the oil pan. The side wall of the oil pan is formed together with the peripheral wall that is distant from the side wall (that is, the inside of the peripheral wall, which is, for example, in the shape of a cylinder or a mortar is the communication hole).

The engine is further defined in claim 2.
As described in (c), it is more preferable to attach a switch (so-called fall switch) for automatically stopping the engine in the case of a fall (overturn or reversal) state. Needless to say, the lubricating oil pressure pump is also stopped when the engine is stopped.

Further, as in claim 3, d) it is also preferable to form a water jacket for cooling in the oil pan.

[0011]

The four-cycle engine of the present invention has the following actions suitable for use in small planing boats and the like.

1) As described in a) above, an oil pan is provided below the bottom of the crankcase via a communication hole, and wet sump system lubrication is performed to collect oil in the oil pan. Compared to a 4-cycle engine, the structure does not become complicated due to lubrication.
In other words, the oil that lubricates the necessary parts of the engine naturally falls through the crankcase into the oil pan below it due to the action of gravity, so there is a separate oil tank like the dry sump method and then there. There is no need to install a recovery pump or the like for sending oil, and there is no need to newly install special lubrication equipment.

2) The oil accumulated in the oil pan does not flow into the combustion chamber even when the engine rolls over or is rotated 180 ° (hereinafter referred to as "reverse"), such as when the small planing boat falls. . This is because the communication hole connecting the crankcase and the oil pan is formed with the peripheral wall as shown in b) above. Since the peripheral wall is firstly separated from the side wall of the oil pan, even when the engine rolls over and the oil in the oil pan moves along the side wall of the oil pan or accumulates on the side wall, Unless the depth of oil exceeds the distance from the side wall to the peripheral wall of the communication hole, the oil will not enter the crankcase through the communication hole. Secondly, since the peripheral wall of the communication hole protrudes downward from the bottom of the crankcase toward the oil pan, even if the engine is turned upside down, oil accumulates around the protruding peripheral wall and the crankcase It does not flow in. That is, unless the depth of the oil in the upside-down state exceeds the protruding dimension of the peripheral wall, the oil in the oil pan will not return to the crankcase through the communication hole.
As described above, as long as the oil does not enter the crankcase from the oil pan, the oil does not reach the combustion chamber through the gap between the cylinder and the piston. From the above points, the distance between the peripheral wall of the communication hole and the side wall of the oil pan and the downward protruding dimension of the peripheral wall should be appropriately determined according to the amount of oil and the shape of the oil pan / crankcase. Good. Even if some oil may return to the crankcase due to the engine's tipping direction, etc., the amount of the oil will be small, so it is easy to prevent the oil from flowing into the combustion chamber from the crankcase with a simple means. Can be done.

3) Based on the intake / exhaust and combustion systems of 4 cycles, as described above, it is preferable from the viewpoint of preventing noise and air pollution.

With respect to the four-cycle engine of claim 2, when the engine (the engine mounted) falls down together with a small planing boat, the switch of the above c) is activated to automatically stop the engine and the lubricating hydraulic pump. To be made. If the automatic stop is performed in the overturned state, it is possible to avoid the oil supplied to the bearing part of the crankshaft from dripping toward the cylinder (combustion chamber). The inconvenience of the pump drawing in air is also prevented.

The conventional four-cycle engine mounted in an automobile or the like does not particularly cool the oil pan with water, but cools it exclusively by air cooling by running wind. Then, d) above
As described above, a water jacket was formed in the oil pan, and cooling water was made to flow inside to cool the water. With this configuration, it is not necessary to apply traveling wind to the outside of the oil pan, and therefore it becomes easy to arrange the engine inside the sealed space. Then, it is convenient to mount the engine on a vehicle such as a small planing boat in which the engine must be arranged in a space surrounded by the bottom hull and the hood, as well as a vehicle in which it is preferable to install the engine in the sealed portion.

[0017]

1 and 2 show a first embodiment of the present invention. This example shows a newly developed four-cycle engine 20
1 is mounted on a small planing boat 1, FIG. 1 is a cross-sectional view of the small planing boat 1 and its engine 20, and FIG. 2 is a perspective view of a part of the small planing boat 1 so that the engine 20 and the like can be seen.
FIG.

The small planing boat 1 is a water vehicle mainly intended for leisure. As shown in FIG. 2, a hood 3, a seat 4, a handle 5 and the like are mounted on a bottom hull 2 for one or more persons.
Two people are allowed to board. The impeller 48 of the water jet pump located at the rear of the lower part is propelled by the water jet pressurized and jetted, and can slide on the water surface. The impeller 48 is driven by the engine 20,
The engine 20 includes a hull 2, a hood 3, and a seat 4
It is mounted in the enclosed space surrounded by etc. in the center of the front and rear of the hull. The output of the engine 20 is transmitted to the drive shaft 47 via the elastic joint 46, and the drive shaft 47 rotates the impeller 48.

The engine 20 has four cycles, and
It is a cylinder and configured as shown in FIG.
First, the engine 20 has a cylinder head 21 at the upper part, and below that, a cylinder 25 and a crankcase 29.
An oil pan 34 is provided. The cylinder head 21 has an intake passage 22 and an exhaust passage 23.
-A valve opening mechanism 24 and the like for opening and closing the valve 23 are incorporated. The intake silencer 11 and the carburetor 12 are connected to the upstream side of the intake passage 22, and the muffler 13 is connected to the downstream side of the exhaust passage 23. A piston 26 is arranged inside the cylinder 25 so as to be vertically slidable, and a space surrounded by the piston 26 and the cylinder head 21 is a combustion chamber 27. The piston 26 is connected to a crank shaft 28, and the crank shaft 28 is supported by a crank case 29 via a bearing (not shown). And crankcase 29
An oil pan 34 for storing oil is tightly attached to the lowest part of the cylinder, and a cylindrical strainer 35 is arranged in the recessed lower part of the oil pan 34, which serves as an oil supply pump (lubrication for performing forced lubrication of each part. Hydraulic pump, not shown). In the range described above, this engine 20 is not particularly different from a general four-cycle engine for automobiles.

The characteristic of the four-cycle engine 20 is the construction of the crankcase 29 and the oil pan 34. That is, as the crankcase 29, the outer shell portion 29c.2
In addition to 9d, the bag-shaped inner portions 29a and 29b are formed,
The bottoms of the inner portions 29a and 29b are located above the oil pan 34. That is, general 4
In the cycle engine, the bottom of the crankcase is nothing but the oil pan, whereas in the four-cycle engine 20, the crankcase 29 (inner parts 29a and 29a
In addition to the bottom of b), the oil pan 34 is provided further below. However, a small diameter communication hole 31 is provided at the bottom of the inner portions 29a and 29b of the crankcase 29 together with the cylindrical peripheral wall 30 projecting downward, and the sliding surface of the cylinder 25, the crankshaft 28, etc. are forcibly lubricated. The oil is dropped onto the oil pan 34 and collected. In addition, the outer shell portion 29c of the crankcase 29
Although 29d is formed integrally with the inner portions 29a and 29b, respectively, it is closely joined to the oil pan 34 by a bolt or the like (not shown), and functionally serves as a side wall of the oil pan 34. There is. As shown in the drawing, a large distance is provided between each surface of the side wall and the communication hole 31, and a considerable amount of space is also provided between the upper end of the side wall and the communication hole 31 (the lower end of the peripheral wall 30) in the vertical direction. Therefore, there is a space S having a sufficient volume in any direction between the side wall and the crankcase 29 (inner portions 29a and 29b).

The four-cycle engine 20 performs wet-sump lubrication in which oil is stored in the four-cycle engine 20, but even when the small planing boat 1 falls down and the engine 20 is turned over or inverted. There is no fear that the oil accumulated in the oil pan 34 will flow into the combustion chamber 27. The oil accumulated on the oil pan 34 moves to the inside or the upper part of the side wall (outer shell portions 29c, 29d) of the oil pan 34 when the engine 20 rolls over or turns over. This is because the space S having a large volume as described above is present between the oil and the oil 31, and the oil is not collected in the space S and enters the crankcase 29 (inner portions 29a and 29b) through the communication hole 31. In other words, each part of the side wall and the communication hole 31
Between the upper end of the side wall and the communication hole 31
Since the vertical dimension between and is sufficient, the oil will not reach the inner parts 29a and 29b during the fall or in the fall state.
It exists only outside of. Inner part 29a ・ 29
As long as oil does not enter the inside of b, cylinder 25
The oil does not reach the inside of the combustion chamber 27 through the gap between the piston and the piston. Depending on how the small planing boat 1 falls, a small amount of splashing oil may reach the inside through the communication hole 31, but since the amount is small, it may enter the combustion chamber 27 and cause inconvenience in operation. I can't reach it.

Further, the small planing boat 1 has a structure shown in FIGS. 3 (a) to 3 (a) for the purpose of automatically stopping the engine 20 when it falls.
The fall switch 18b is provided as shown in (c). As shown in FIG. 2A and FIG. 2, the tipping switch 18b is an electrical equipment storage box 8 (provided that it is waterproof to accommodate electrical equipment such as non-waterproof electrical equipment) arranged inside the body of the small watercraft 1. 3) Installed in a fully sealed box)
As described above, the ignition device 18 of the engine 20 is directly connected. In the same (b), reference numerals 18a, 18c, 18d, 1
8e is an exciter coil / CDI unit /
An ignition coil and an ignition plug, and the ignition device 18 is configured by them. As the overturn switch 18b itself, a weight-type switch shown in FIG. 3 (c) was used. That is, a set of open contacts 18q is provided symmetrically on the left and right (the left and right direction of the ship) in the circuit shown by the grounded electric wire 18p, and a U-shaped track 18s is provided between the contacts 18q. A weight 18r is disposed so as to be movable along the weight. When the orbit 18s is tilted to the left or right by a certain angle (for example, 60 °) or more, the moved weight 18r contacts one contact 18q and closes it.
The output from the exciter coil 18a of the ignition device 18 shown in (b) is grounded to stop the engine 20. With the above configuration, when the small planing boat 1 rolls over or reverses, the engine 20 including the lubricating hydraulic pump and the like immediately stops, and the oil supply to the crankshaft 28 and the like in FIG. 1 also stops. Become. Then, the oil directly supplied to the inside of the crankcase 29 without passing through the communication hole 31 also disappears, which is more preferable in the sense that the oil does not flow into the combustion chamber 27. Of course, other types of tipping switches can be used, and in addition to turning the engine 20 off by grounding it, turning on the engine 20 by grounding can also be used.

Besides, as shown in FIG.
A passage for cooling water, that is, a water jacket 34a is formed in the oil pan 34, and water taken out from the water intake tool 7 opening at the jet outlet 6 of the water jet shown in FIG. 2 is passed therethrough. Specifically, the connector 34b (FIG. 1 or 2) of the water jacket 34a (FIG. 1)
Is connected to the water intake tool 7 (FIG. 2) via a tube (not shown), and the other connecting tool 34c (FIGS. 1 and 2) is similarly a tube for cooling water of the cylinder 25 (FIG. 1). Connector 25
a (same). By doing so, the water of the water jet pump (FIG. 2) cools the oil pan 34 (same) together with the cylinder 25 (FIG. 1) and the cylinder head 21 (same). As shown in FIG. 2, the engine 20 is arranged in a closed space surrounded by the bottom hull 2 and the hood 3 and is not air-cooled even while gliding, but due to the water cooling structure, it is appropriately cooled.

In the four-cycle engine 20, the cylindrical peripheral wall 30 provided around the communication hole 31 as shown in FIG. 1 is not essential. Even if it is not there, the oil in the case of a fall will be crankcase 29.
This is because it is collected in the space S outside the (inner portions 29a and 29b) and does not flow into the communication hole 31. In that case, the above-mentioned inner portions 29a and 29b protruding downward
Is a bottom portion of the crankcase 29 and also functions as a kind of peripheral wall (a peripheral wall expressed in the claims) for the communication hole 31.

Next, FIGS. 4 and 5 show a second embodiment of the present invention. Figure 4 shows a new 4-cylinder 4-cycle engine 60
5 is a cross-sectional view of FIG. 5, and FIG. 5 is a side view of the small planing boat 1 equipped with the same (the engine 60 and the like are shown in a see-through state).
Is. The small planing boat 1 of FIG. 5 is the same as that shown in FIG. 2, and the same parts are designated by the same reference numerals and the description thereof is omitted. The engine 60 of FIG. 4 has a cylinder head 61, a cylinder 65, a piston 66, a crankshaft 68,
It is similar to the engine 20 of the above-described first embodiment (FIGS. 1 and 2) in that it is provided with the crankcase 69 and the like and is connected to the intake silencer 51, the carburetor 52, and the muffler 53 (FIG. 5).

Compared to the first embodiment, this embodiment firstly differs in the layout of the engine 60 and the like. That is, in the first embodiment, as shown in FIG. 1, the cylinder 25 is tilted to the side (side of the boat 1) and the storage space for the intake silencer 11 is secured next to it, whereas in the second embodiment. As shown in FIGS. 4 and 5, the engine 60 is placed horizontally (the crankshaft 68 is directed to the left and right of the boat 1), the cylinder 65 is largely tilted, and the intake silencer 51 is arranged on the engine 60. All such layouts are
This is for housing the 4-cycle engine 20 or 60, which is considerably larger than the 2-cycle engine, in the limited space within the seat 4 of the small planing boat 1. In the case of the second embodiment, the output of the engine 60 placed horizontally is taken out from the shaft 85 rearward through the spur gear pair 81, the bevel gear pair 82, the spur gear pair 83, etc. as shown in FIG. Transmission from 86 to the drive shaft 87 of the impeller 88 as shown in FIG.

The four-cycle engine 60 of FIG. 4 is also slightly different from the engine 20 of the first embodiment (FIG. 1) in the construction of the crankcase 69 and the oil pan 74. FIG.
In the engine 20 of FIG. 4, the bottom of the crankcase 29 (inner portions 29a and 29b) is provided in the space surrounded by the oil pan 34 and the side wall portion thereof.
At 0, as shown in FIG. 4B, the bottom of the crankcase 69 and the oil pan 74 are arranged so as to form separate spaces. That is, the upper case 69a (see FIG.
(a)) and the lower case 69b that is the bottom thereof, and further, the timing chain 68a of the crankshaft 68 (FIG. 4 (b))
Crankcase 69 surrounded by a cover 69c for the same
An oil pan 74 that forms a closed space together with the upper side wall 73 is arranged below the space. The above-mentioned members such as the crankcase 69 and the oil pan 74 are integrally connected by using bolts (not shown). The upper and lower spaces formed as described above are connected by two communication holes 71 as shown in FIGS. 4 (a) and 4 (b), and the lower case 69b of the crankcase 69 is connected around each communication hole 71. The cylindrical peripheral wall 70 protruding toward the oil pan 74 is formed. In the closed space above the oil pan 74, a large space S is secured around and around the peripheral wall 70 of the communication hole 71 as shown in FIG. It should be noted that the strainer 75 is arranged in the lower portion of the oil pan 74 in the shape of a depression and is connected to a lubricating hydraulic feed pump (not shown), as in the case of the first embodiment.

This four-cycle engine 60 shown in FIG.
Also uses so-called wet sump lubrication, but when the small planing boat 1 falls over, the oil pan 7
This has the advantage that the oil accumulated in the No. 4 does not flow into the combustion chamber 67. The reason why such inflow does not occur even when the vehicle falls over is that there is a large space S around and around the peripheral wall 70 (communication hole 71) in the space of the oil pan 74. In other words, when the engine 60 rolls over or reverses, the oil collects in the space S and hardly reaches the inside of the crankcase 69 from the communication hole 71, and therefore the oil goes through the inner wall of the cylinder 65 to the combustion chamber 67. There is no such thing.

Since the volume of the space S is limited to a portion shown on the left side of the peripheral wall 70 in FIG. 4 (b), a small amount of oil is communicated when the engine 60 falls with the side down. It may return to the inside of the crankcase 69 through the hole 71. However, even in that case,
For the following reason, there is no possibility that oil will enter the combustion chamber 67. One of the reasons is that the oil reaching the crankcase 69 is not the whole oil on the oil pan 74 but a small amount. The second reason is that when the engine 60 falls to the above side, the oil that has entered the crankcase 69 reaches the portion of the timing chain 68a (FIG. 4 (b)) and the cylinder 65 that is in the direction perpendicular to it. (Fig. 4 (a))
Don't go to Another reason is that as a part of the crankcase 69, an internal partition 69d is formed so as to surround each pair of webs of the crankshaft 68 as shown in FIG. 4B.
Since the communication hole 69e for dropping oil is provided, it is more difficult for oil to enter the cylinder 65. The peripheral wall 70 is longer than the size of the communication hole 71.
It is also advantageous in that it prevents the oil inside the crankcase 69 from entering even when the oil splashes up sharply.

As in the case of the first embodiment, also in the second embodiment, a tipping switch (not shown) is provided at any location of the small planing boat 1 and connected to the engine 60, When the vehicle falls, the engine 60 is automatically stopped. This is because the supply of oil to the inside of the crankcase 69 such as the crankshaft 68 in FIG. 4 is stopped by stopping the engine 60 including the lubricating hydraulic pump (not shown) and the like.

Further, as shown in FIG.
A water jacket 74a is also formed in the oil pan 74 of No. 0 so that the water taken out from the jet port 6 (FIG. 5) of the water jet is passed through the inside. Reference numerals 74b and 74c in FIG. 4 (a) are connecting members that communicate with the inside of the water jacket 74a.
For sending to the cooling water connector 65a.

Two examples of the engine used for the small planing boat have been introduced above. However, the four-cycle engine of the present invention is not limited to this, and a buggy vehicle (ATV) for enjoying traveling on off-road or on snow. It is also suitable to be mounted on.

[0033]

The four-cycle engine of the present invention is extremely suitable for use in a vehicle / apparatus, such as a small planing boat, which is supposed to fall over, for the following reasons.

1) Since the wet sump type lubrication is performed, it is not necessary to make the structure particularly complicated for lubrication as compared with the conventional general four-cycle engine. Therefore, it is easy to manufacture, is compact and occupies a small space,
It also has the advantage of low cost.

2) Even if a small planing boat equipped with this engine falls, the oil in the oil pan does not flow into the combustion chamber, so that it is possible to smoothly restart after returning the posture.

In the case of the four-cycle engine of claim 2,
Furthermore, when a small planing boat falls down, a switch (fallover switch) works to automatically stop the lubrication hydraulic pump with the engine, which is even more preferable in point 2) above.

The four-cycle engine of claim 3 can be freely arranged because the oil pan does not need to be air-cooled, and is suitable for various applications including small planing boats in which the engine must be arranged in a closed space. There is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a four-cycle engine 20 which is a first embodiment of the present invention.

FIG. 2 is a side view showing a small planing boat 1 equipped with the four-cycle engine 20 of FIG. 1, showing a part thereof in a see-through manner.

FIG. 3 is a diagram showing a tipping switch 18b and the like in the small planing boat 1, FIG. 3 (a) showing the arrangement of the switch 18b in a cross-sectional view of the small planing boat 1, and FIG. 3 (b) showing the ignition device 18; The connection of the switch 18b is shown, and the same (c) is a schematic diagram showing the configuration of the overturn switch 18b itself.

FIG. 4 (a) is a cross-sectional view showing the main part of a four-cycle engine 60 according to a second embodiment of the present invention, and FIG. 4 (b) shows the same.
It is bb sectional drawing in (a).

5 is a side view showing a small planing boat 1 equipped with the 4-cycle engine 60 of FIG. 4, and a part thereof is seen through.

[Explanation of symbols]

 1 Small planing boat 18b switch (overturn switch) 20.60 4 cycle engine 29.69 crankcase 30.70 peripheral wall 31.71 communication hole 34.74 oil pan 34a.74a water jacket

Claims (3)

[Claims] 1. An oil pan is disposed further below the bottom of the crankcase, and the spaces inside the two are connected by a communication hole provided at the bottom of the crankcase, and the communication hole is formed from the bottom of the crankcase to the oil pan. A four-cycle engine, which is formed with a peripheral wall projecting downward toward the oil pan and having a distance from the side wall of the oil pan. 2. The four-cycle engine according to claim 1, further comprising a switch for automatically stopping the engine when the vehicle falls over. 3. The oil pan according to claim 1, wherein a water jacket for cooling is formed on the oil pan.
Cycle engine.