JP2004270640A - Engine upper structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine upper structure capable of preventing exhaust emission, oil hammer or the like by devising a shape of a baffle plate provided on a vent hole (an inlet) of a breather provided on an upper part of a valve arm chamber of an engine, and a shape of an engine starting aid filling passage of, and disposing the breather and the engine starting aid filling passage in a compact and collective manner. <P>SOLUTION: A slit 34 with a lower portion thereof opened is formed in a baffle plate 33 formed around a vent hole 36 of a breather 30, a throttle 45 is formed in a filling passage 42 of an engine starting aid, and the breather 30 and the filling passage 42 are integrated with a valve arm case 21. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine upper structure in an engine. More specifically, the present invention relates to a structure of a cylinder head from a breather section to an intake section.
[0002]
[Prior art]
Conventionally, in an engine, a breather chamber is provided in a valve arm case that covers the upper part of a cylinder head to adjust the pressure between the inside of the valve arm case and the outside air pressure, and to prevent oil mist from being discharged outside the machine. There is another type in which a blow-by gas containing oil mist is separated into a gas component and an oil component by the breather chamber.
The breather chamber is constituted by a space surrounded by a side wall of a valve arm case (breather case) and a bottom plate provided at a constant interval with respect to the back surface of the valve arm case. It is configured to capture oil in the blow-by gas by a net or the like.
In such a breather device, by integrally forming the side wall and the bottom plate of the breather case, the number of parts and the number of assembling steps are reduced, the productivity is improved, and the noise generation due to the vibration of the engine is eliminated. (For example, see Patent Document 1).
[0003]
There is also a breather provided with a check valve for preventing the inside of the valve arm case of the engine from becoming high pressure. Such a breather has a structure in which high-pressure gas escapes from a check valve that prevents backflow, and returns to an intake port. Lubricating oil scattered in the valve arm chamber is accumulated in the breather chamber of the breather, and when a certain amount of the lubricating oil accumulates, the lubricating oil adheres to the vicinity of the inlet of the check valve, and the lubricating oil is deposited on the check valve. And the gas containing the lubricating oil returns to the intake port. If the amount of the lubricating oil is small, the effect is not so large. However, if the amount of the lubricating oil sucked inevitably increases, the lubricating oil burns, and exhaust emission is generated, resulting in poor exhaust.
In order to prevent the intrusion of the lubricating oil causing the exhaust emission as much as possible, a baffle plate is provided around the vent hole of the breather.
[0004]
On the other hand, in a place where the air temperature is low, such as in winter or in a cold region, the temperature of the air is low and the gas mixture in the combustion chamber does not easily reach the combustion temperature, so that the engine may be difficult to start. Therefore, in a diesel engine, in order to increase the compression ratio so that the mixed gas becomes easy to burn, a passage for injecting a starting auxiliary agent such as oil connected to the intake port is provided, and the starting auxiliary agent is injected from this passage. The starting aid enters the combustion chamber from the intake port. There is also known a technique in which the compression ratio is increased by the amount of the starting auxiliary agent put in the combustion chamber, the mixed gas is easily burned, and the engine is easily started.
[0005]
[Patent Document 1]
Published Japanese Utility Model Application No. Hei 6-4311
[Problems to be solved by the invention]
However, the baffle plate provided around the vent hole of the breather described above forms a substantially cylindrical space with the wall surface of the valve arm case, and when the breather chamber is filled with a certain amount of lubricating oil, the engine is stopped. When the vehicle is mounted on a moving vehicle or the like, there is a possibility that the engine may tilt or vibrate, causing the liquid level of the accumulated lubricating oil to fluctuate and sucking the lubricating oil as it is.
In addition, when injecting oil, which is an engine start-up aid, with a conventional injection aid injection passage shape, depending on the user, more than a specified amount of oil may be introduced, and if this occurs, excess oil may enter the combustion chamber. This may cause an oil hammer to damage the connecting rod and the like. Further, if the injection passage of the starting auxiliary agent is configured differently, the cost is increased.
Therefore, the present invention seeks to provide an upper structure of an engine in which these are compactly arranged.
[0007]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0008]
That is, in the first aspect of the present invention, in the engine in which the breather is provided in the upper portion of the valve arm chamber, a slit is provided to open a lower part of a baffle plate provided around the vent of the breather in the valve arm chamber.
[0009]
According to a second aspect of the present invention, there is provided an engine in which a breather is provided in an upper part of the valve arm chamber, and a recirculation passage of the breather communicates with a starting auxiliary agent injection port, and a throttle is provided in the starting auxiliary agent injection passage.
[0010]
According to a third aspect of the present invention, the recirculation passage and the starting auxiliary agent injection passage of the breather are formed integrally with the valve arm case.
[0011]
The engine according to claim 4, wherein a breather is provided in an upper portion of the valve arm chamber, and a recirculation passage of the breather and a starting auxiliary agent injection port communicate with an intake port of a cylinder head. The inner surface is shaped so as to approach the tangential direction of the cylinder liner in plan view.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention will be described.
1 is a front sectional view of an engine according to the present invention, FIG. 2 is a side sectional view of an upper portion of the engine, FIG. 3 is a plan view of a valve arm case, FIG. 4 is a bottom view thereof, and FIG. FIG. 6 and FIG. 6 are BB sectional views, and FIG. 7 is a plan sectional view of the cylinder head.
[0013]
First, the overall configuration of the engine according to the present invention will be described with reference to FIGS.
The engine 1 has a cylinder block 2 at the upper part of its body and a crankcase 10 at the lower part. The cylinder block 2 has a cylinder liner 17 formed in the center in the vertical direction and houses the piston 4 slidably in the vertical direction. The crankshaft 3 is pivotally supported by the crankcase 10 in the front-rear direction, and the piston 4 and the crankshaft 3 are connected by a connecting rod 18.
The upper part of the cylinder block 2 is covered by a cylinder head 5, and an intake valve 22, an exhaust valve 23, a fuel injection nozzle 6, and the like are arranged on the cylinder head 5. The upper part of the cylinder head 5 is covered by a valve arm case 21. A valve arm chamber 20 is formed, and a muffler 8 is arranged on one side of the valve arm case 21 and a fuel tank 9 is arranged on the other side.
The valve arm chamber 20 is provided with the upper end portions of the intake valve 22 and the exhaust valve 23, the upper end portions of the intake push rod 24 and the exhaust push rod, the mounting portion of the valve arm 25 and the fuel injection nozzle, and the like, which will be described later. A breather 30 is provided.
[0014]
A governor 11 is disposed in a crankcase 10 below the cylinder block 2, and a fuel injection pump 12 is disposed above the governor 11. The power of the fuel injection pump 12 is transmitted to a camshaft 13 via a gear provided on the crankshaft 3, and a cam 14 provided on the camshaft 13 pushes and pulls a plunger 15 of the fuel injection pump 12. The fuel from the fuel tank 9 is sucked, a predetermined amount of fuel is supplied to the fuel injection nozzle 6 at a predetermined timing, and the fuel is injected into the combustion chamber 19.
[0015]
2, the intake valve 22 and the exhaust valve 23 are disposed above the piston 4, and valve heads 22a and 23a are respectively seated on valve seats formed on the lower surface of the cylinder head 5. Between the internal combustion chamber 19 and the intake port 5 a or the exhaust port 5 b formed in the cylinder head 5.
The intake port 5a communicates with the air cleaner, and the exhaust port 5b communicates with the muffler 8 via the exhaust manifold 26.
The respective valve rods 22b and 23b of the intake valve 22 and the exhaust valve 23 penetrate upward through the cylinder head 5 and protrude into the valve arm chamber 20, in which the springs 27 are fitted. Thus, the intake valve 22 and the exhaust valve 23 are slid upward to urge the intake valve 22 and the exhaust valve 23 to close.
[0016]
Next, the breather 30 according to the present invention will be described with reference to FIGS.
As described above, the breather 30 for adjusting the pressure between the inside of the valve arm chamber 20 and the outside air pressure is provided in the valve arm chamber 20 on the intake port 5a side of the valve arm case 21 (in this embodiment, It is provided integrally with the valve arm case 21 at the upper portion (right side in FIG. 2).
The breather 30 communicates with the outside atmosphere so that the pressure in the valve arm chamber 20 does not increase or decrease, and a part of the breather 30 prevents backflow provided integrally with the valve arm case 21. Air is released by a check valve 31 for discharging the air through a breather recirculation passage 32 and an exhaust port 37 formed in the valve arm case 21, and passes through a passage 28 formed in the cylinder head 5, to form the intake port. The structure returns to 5a.
[0017]
Lubricating oil is scattered in the valve arm chamber 20 to lubricate the upper ends of the intake valve 22 and the exhaust valve 23 and the valve arm 25, etc., which are provided in the valve arm chamber 20. A baffle plate 33 is provided integrally with the valve arm case 21 around an air hole 36 serving as an inlet of the breather 30 in order to return the lubricating oil which has become a liquid into the crankcase 10. I have.
In other words, when the pressure in the valve arm chamber 20 is released by the breather 30, the mist-like lubricating oil hits the baffle plate 33 when entering the vent hole 36, and small particles grow to become liquid. It falls down and returns to the inside of the crankcase 10 through the push rod chamber and the like.
[0018]
However, when the baffle plate is provided around the lower part of the ventilation hole 36, when a large amount of lubricating oil is accumulated in the valve arm chamber 20 or when the main body is inclined and the oil level rises, it may be sucked up like a straw. . Therefore, the baffle plate 33 is composed of a plate part 33a and a plate part 33b, and the plate part 33a and the plate part 33b are separated from each other at a distance from each other in a substantially vertical direction. It is formed integrally and protrudes so as to surround the ventilation hole 36 communicating with the check valve 31. That is, the vertical slit 34 whose lower part is opened is provided between the plate portion 33a and the plate portion 33b. However, the slit 34 can also be provided between the plate portions 33a and 33b and the side wall of the valve arm case 21.
[0019]
With this configuration, as shown in FIG. 5, the lubricating oil rises to near the lower end of the baffle plate 33, the main body of the engine 1 vibrates, and the engine 1 shakes when mounted on a moving vehicle. However, since the slits 34 are formed in the baffle plate 33 as in the present invention, air can escape from the slits 34, so that the lubricating oil accumulated in the valve arm chamber 20 is sucked into the check valve 31. Can be prevented from going out.
That is, as long as the lubricating oil is not filled in the valve arm chamber 20, it is possible to prevent the infiltration of the lubricating oil into the check valve 31 side, and it is possible to prevent the generation of the exhaust emission caused by the lubricating oil, thereby improving the exhaust performance.
Further, since the slit 34 can be easily formed, there is no need to provide a separate hole by drilling or the like instead of the slit 34, and the above-described effect can be obtained with a simple configuration.
[0020]
Next, the structure of the starting auxiliary agent injection section 40 according to the present invention will be described.
As shown in FIGS. 2 to 5, at one end of the valve arm case 21, a starting auxiliary agent injection section 40 is provided integrally with the valve arm case 21. Oil, which is a starting auxiliary agent for smoothly starting the engine, is injected.
The starting aid injection section 40 communicates with the intake port 5a, and the oil injected from the starting aid injection port 41 passes through an injection passage 42 penetrating the passage 28 formed in the cylinder head 5. It is dropped into the intake port 5a and enters the combustion chamber 19 from the intake port 5a. By doing so, the oil reduces the volume in the combustion chamber 19 by the amount of the oil, increases the compression ratio of the mixed gas, and facilitates the start of the engine. Note that a cap 44 is inserted into the injection port 41 except at the time of injection of the starting aid, thereby preventing foreign matter from entering from outside.
[0021]
When injecting the starting aid, a throttle 45 is formed in the injection passage 42 so that a predetermined amount or more of oil is injected into the combustion chamber 19 and an excessively high pressure is not generated to generate an oil hammer.
That is, by providing the throttle 45 in the middle of the injection passage 42, the oil injected from the injection port 41 temporarily accumulates in the funnel-shaped pool portion 42a formed in the injection passage 42 before entering the throttle 45, Thereafter, the appropriate amount is dropped.
By adopting such a structure, when injecting the oil of the starting aid, even a general user or the like can visually confirm the amount to be added, and a large amount of oil is sucked into the combustion chamber 19 at one time to generate an overrun. And oil hammer can be prevented.
[0022]
Further, the breather recirculation passage 32 and the starting auxiliary agent injecting passage 42 have respective discharge ports formed as discharge ports 37 formed in the valve arm case 7. That is, the breather 30 and the starting auxiliary agent injecting section 40 are provided on the intake port 5a side (the right side in FIG. 3) of the valve arm case 21, and the breather recirculation passage 32 and the starting auxiliary agent injecting passage 42 are respectively defined as described above. It is configured integrally with the valve arm case 21 and has a structure communicating with one outlet 37.
With such a configuration, the breather 30 and the starting auxiliary agent injecting section 40 can be collectively arranged in the valve arm case 21, so that the number of parts can be reduced, cost can be reduced, and space can be saved. Can also be achieved.
[0023]
Subsequently, the shape of the intake port 5a according to the present invention will be described.
In particular, in a diesel engine such as the engine 1 according to the present invention, it is necessary that the air and the fuel be well mixed in order to completely burn the fuel in a short time. Therefore, the engine is designed so that swirls such as air, air-fuel mixture, and combustion gas are generated in the combustion chamber.
In particular, the intake port is made in a shape that is conscious of swirl generation, and as a method to create a strong swirl as much as possible without obstructing the flow of airflow, the intake port is provided eccentrically with respect to the combustion chamber, and the shape of the valve is changed. Ingenious methods have been developed.
[0024]
Therefore, as shown in FIG. 7, when the intake valve and the exhaust valve are arranged in the front-rear direction and the intake valve and the exhaust valve are arranged eccentrically to the right with respect to the center of the cylinder, the intake port 5a Of the cylinder liner 17 is disposed on the left and right sides (in the present embodiment, left side (upper side in the figure) of the machine body left and right direction) with respect to the center of the cylinder liner 17. The intake port 5a formed in the cylinder head 5 enters from the left side and is bent to the right side to form a passage shape spirally toward the center of the intake valve. A portion corresponding to the outer side of this passage, that is, a plan sectional shape of the outer inner wall 5c is shaped so as to approach the tangent t direction of the inner periphery of the cylinder liner 17 in plan view. In other words, from the inlet of the intake port 5a on the outer inner wall 5c to just before crossing the inner periphery of the cylindrical cylinder liner 17, the connection is made smoothly so as to approach the arc shape (circumferential shape) of the cylinder liner 17 as much as possible. Shape. Then, the inner wall 5c outside the intake port 5a after crossing the inner wall 5c and the inner periphery of the cylinder liner 17 is smoothly connected to the outer peripheral circle s of the intake valve 22 in plan sectional view, and further, to the outer periphery u of the intake inlet opening. As a parabolic curve that connects smoothly, a spiral curve is formed, and the intake port 5a is formed in the cylinder head 5 with a shape having an intake port having a size capable of inhaling a sufficient amount of air. Are placed.
[0025]
By forming the intake port 5a in such a shape and arrangement, the air having the smallest resistance can flow in the outside of the intake port 5a, so that the flow velocity of the outside air is increased. Therefore, the difference in the flow velocity of the air taken in between the inside and outside of the intake port 5a becomes large, and the eddy of the air flow is easily generated. That is, swirl is likely to occur due to the shape of the intake port 5a, and the air and fuel are well mixed, which leads to promotion of combustion.
[0026]
【The invention's effect】
The present invention is configured as described above, and has the following effects.
[0027]
That is, in the engine having the breather provided in the upper part of the valve arm chamber, the slit for opening the lower part of the baffle provided around the ventilation hole of the breather in the valve arm chamber is provided. Even if the lubricating oil accumulated in the baffle plate is at or above the position of the lower end of the baffle plate, air can escape from the slit, and lubricating oil is not sucked from the vent hole. In other words, with a simple configuration, the lubricating oil does not burn, preventing the generation of exhaust emissions and improving the exhaust performance.
[0028]
According to a second aspect of the present invention, there is provided an engine in which a breather is provided at an upper portion of the valve arm chamber, and a recirculation passage of the breather communicates with a starting auxiliary agent injection port. The amount of injection of the starting aid is automatically limited by the throttling, so that excessive injection can be prevented. In addition, since the injection amount is limited and the injection amount is slow, the injection amount can be checked while visually checking the injection amount.
[0029]
According to the third aspect of the present invention, since the recirculation passage and the starting auxiliary agent injection passage of the breather are integrally formed in the valve arm case, the recirculation passage and the starting auxiliary agent injection passage of the breather can be collectively arranged, and the number of parts can be reduced. And cost and space can be reduced.
[0030]
According to a fourth aspect of the present invention, there is provided an engine in which a breather is provided in an upper portion of a valve arm chamber, and a recirculation passage of the breather and a starting auxiliary agent inlet communicate with an intake port of a cylinder head. Since the outer inner surface has a shape approaching the tangential direction of the cylinder liner in plan view, strong swirl is easily generated without obstructing the air flow as much as possible, and the combustion efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an engine according to the present invention.
FIG. 2 is a side sectional view of an upper portion of the engine.
FIG. 3 is a plan view of a valve arm case.
FIG. 4 is a bottom view of the same.
FIG. 5 is a sectional view taken along line AA in FIG. 3;
FIG. 6 is a sectional view taken along line BB of FIG.
FIG. 7 is a plan sectional view of a cylinder head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 5 Cylinder head 5a Intake port 5c Inner wall 17 Cylinder liner 20 Valve arm chamber 21 Valve arm case 30 Breather 32 Breather recirculation passage 33 Baffle plate 34 Slit 36 Vent hole 40 Starting auxiliary agent injection part 41 Inlet 42 Injection passage 45 Throttle

Claims (4)

In an engine having a breather provided in an upper part of a valve arm chamber, a slit is provided for opening a lower part of a baffle provided around a vent of the breather in the valve arm chamber. An engine upper structure in which a breather is provided in an upper portion of a valve arm chamber, and a recirculation passage of the breather communicates with a starting auxiliary agent injection port, wherein a throttle is provided in the starting auxiliary agent injection passage. 3. The engine upper structure according to claim 1, wherein the recirculation passage and the starting auxiliary agent injection passage of the breather are formed integrally with the valve arm case. An engine in which a breather is provided at an upper part of the valve arm chamber, and a recirculation passage of the breather and a starting auxiliary agent inlet communicate with an intake port of a cylinder head. An engine upper structure characterized by a shape approaching the tangential direction of the cylinder liner.

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