JP2024005399A - head cover structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head cover structure which can avoid a risk of freezing as much as possible by installing an oil separator in a head cover limited in volume to thereby shorten a length of an external pipe for blow-by gas, and which has been rationally improved so as to be capable of providing a sufficient oil capture action while keeping an engine compact.

SOLUTION: A head cover structure is configured to introduce blow-by gas into an intake passage C after passing it through the inside of a head cover H. An oil separator A for and capturing and removing oil from the blow-by gas is arranged in the head cover H, and a gas introduction part 7 as an inlet for the blow-by gas in the oil separator A is arranged at an upper end part of the oil separator A. Blow-by gas from a crankcase passes through a circulation space part S sandwiched by an inner surface of the head cover H and an outer surface of the crankcase A and flows to the gas introduction part 7.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a head cover structure that is applied to various engines equipped with a blow-by gas recirculation device, and relates to a head cover structure that includes an oil separator.

BACKGROUND ART Many industrial diesel engines have a structure in which blow-by gas is passed through a cylinder head cover (hereinafter referred to as a head cover) and then returned to an intake passage, a so-called blow-by gas recirculation device.

In a configuration in which blow-by gas from the crankcase passes through the inside of the head cover, is taken out outside the head cover, and is returned to the intake passage, a passage for the blow-by gas is often provided above the valve mechanism within the head cover. Inside the head cover, the blow-by gas passage tends to be a narrow flat passage vertically, so an oil separator that captures oil components from the blow-by gas was generally installed outside the head cover as a dedicated part (for example, in the patent Reference 1).

The structure in which the oil separator is placed on the side of the cylinder block has the advantage of being able to have sufficient capacity because there is not as much space restriction as there is in the head cover. However, since the oil separator, which is a dedicated part, is added as an auxiliary device to the engine, there are the following disadvantages.

In other words, dedicated piping means such as hoses are used for the inlet and outlet passages of the blow-by gas to the oil separator, so space is required to arrange these piping means (because the engine is bulky in the lateral direction). ). Furthermore, since the gas passage from the head cover to the intake passage becomes longer and the length of external piping also becomes longer, there is an increased possibility that moisture contained in the blow-by gas will freeze in cold weather.

Japanese Patent Application Publication No. 2018-35787

The purpose of the present invention is to provide an oil separator inside the head cover, which has a limited capacity, through structural innovation, to shorten the length of the external piping for blow-by gas, thereby avoiding the risk of freezing as much as possible, and The object of the present invention is to provide a head cover structure that is rationally improved so that a sufficient oil trapping effect can be obtained while suppressing oil oxidation.

The present invention provides a head cover structure including:
It is configured to guide blow-by gas through the inside of the head cover and then into the intake passage.
An oil separator that captures and removes oil from blow-by gas is provided inside the head cover,
The oil separator is characterized in that a gas introduction portion, which is an inlet for blow-by gas, is provided at an upper end portion of the oil separator.

It is advantageous if the blow-by gas from the crankcase flows to the gas introduction part through the circulation space sandwiched between the inner surface of the head cover and the outer surface of the oil separator. The circulation space may include a space between the inner surface of the ceiling wall of the head cover and the top surface of the oil separator, and/or a space between the inner surface of the side wall of the head cover and the side surface of the oil separator. It's even more convenient.

For the present invention other than the above, please refer to claims 4 to 9 in the claims.

According to the present invention, since the oil separator is built into the head cover, external piping can be omitted or the length can be drastically reduced, and the external piping and oil separator are not exposed to cold air in winter, etc., and are not exposed to the surroundings. The oil separator can be expected to have heat retention and insulation effects due to the blow-by gas that exists. Therefore, the inconvenience of water freezing inside the oil separator or the external piping and clogging can be avoided.

Since the blow-by gas inlet is located at the upper end of the oil separator, the travel distance of the blow-by gas to the gas inlet in the head cover can be increased without difficulty, and the ability to capture oil components from the blow-by gas can be strengthened. can. Then, the blow-by gas flowing downward from the oil separator changes its direction and moves forward, and the inertial separation caused by the change in direction promotes the trapping action of oil components.

As a result, we installed an oil separator inside the head cover to shorten the length of the external blow-by gas piping to avoid the risk of freezing as much as possible, and to suppress the increase in engine size while ensuring a sufficient oil trapping effect. As a result, a reasonably improved head cover structure can be provided.

Note that if the oil filter is installed in the gas inlet of the oil separator, the blow-by gas flows from top to bottom within the oil separator, creating a cleaning action that prevents foreign matter (such as carbon) from accumulating on the oil filter. can be expected.

Vertical cross-sectional view of main parts showing an overview of the head cover and its internal structure Cross-sectional view of main parts showing an overview of the head cover and its internal structure Bottom view of upper head cover Top view of industrial diesel engine Top view of oil separator Cross-sectional view taken along the Z-Z line in Figure 5 Cross-sectional view taken along the Y-Y line in Figure 6 Detailed longitudinal cross-sectional view of main parts showing the internal structure of the head cover

Embodiments of the head cover structure according to the present invention will be described below with reference to the drawings in the case of an industrial diesel engine. The structure of the oil separator A is simplified to some extent (eg, the cover lid 18 is omitted) in FIGS. 1 and 2 for the sake of simplicity. Further, in FIG. 5, only a portion of the suction port 18a is illustrated for simplicity.

In an industrial diesel engine E shown in plan view in FIG. 4, 28 is a supercharger (turbocharger), 29 is a cooling fan, 30 is an exhaust treatment device, 31 is an alternator, 32 is a water flange, 33 is a transmission case, 34 is the intake manifold, and H is the head cover. This engine E is provided with a blow-by gas recirculation device B, which will be described later.

As shown in FIGS. 1 to 3, the head cover H is composed of a lower head cover 2 that is attached to the cylinder head 1 by bolts, and an upper head cover 3 that is attached to the lower head cover 2 by bolts. has been done. The head cover H accommodates an oil separator A that captures and separates oil components in the blow-by gas.

Blowby gas from the crankcase passes through the inside of the cylinder head 1, passes through the lower head cover 2 and the upper head cover 3, and enters the oil separator A. The blow-by gas from which oil components have been removed to some extent by the oil separator A is discharged from the gas outlet 3G of the upper head cover 3 to the outside of the head cover H, passes through the return passage 27, and flows into the intake passage (fresh air introduction path) C. A blow-by gas recirculation device B is provided.

That is, the blow-by gas g is configured to pass through the inside of the head cover H and then guided to the intake passage C, and an oil separator A that captures and removes oil from the blow-by gas g is provided inside the head cover H. A gas introduction section 7, which is an inlet for gas g, is provided at the upper end of the oil separator A. Note that 35 shown in FIGS. 1 and 4 is a wire harness that drives a fuel injector (not shown), and 36 shown in FIGS. 1 and 3 is an extraction hole through which the wire harness 35 is passed.

As shown in FIGS. 1, 2, and 5 to 8, the oil separator A includes a main body case 4 consisting of an upper first case 5 and a lower second case 6, and an element case (filter case). 9A. A gas introduction section 7 that is an inlet for blow-by gas, a gas outlet section 8 that is an outlet for blow-by gas, an oil element (oil filter) 9 that captures oil components, a check valve 10, a bypass valve 16, etc. are provided. .

As shown in FIGS. 1, 2, 6, and 7, the oil element 9 has a rectangular shape that is long in the front and back and relatively short in vertical width when viewed from above, and is housed in a dedicated element case 9A. It is assembled and integrated with a plurality of bolts 22 (four places) on the upper side of the main body.
The element case 9A includes an open box-shaped main body case part 9a that houses the oil element 9, and a plate-like cover lid (an example of a plate-like body) 18 that is bolted at multiple locations on the main body case part 9a. It is configured.
The cover lid 18 is formed with a large number of suction holes 18a (also serving as the gas inlet 9g and the gas introduction part 7), which are, for example, circular holes, and the blow-by gas g flowing to the ceiling inside the upper head cover 3 is , it is advantageous to enter the element case 9A through the large number of suction holes 18a.

As shown in FIGS. 6 and 7, a discharge case portion 9b that projects downward is formed on the lower side of the rear portion of the main body case portion 9a. For example, the discharge case part 9b, which has a circular shape when viewed in the vertical direction, is fitted into the introduction opening 5a formed at the upper rear part of the first case 5 in a liquid-tight manner via a seal ring (notation notation). has been done.

In other words, the blow-by gas that has passed through the oil element 9 (from which some oil components have been removed) and the oil components (engine oil, water, etc.) captured by the oil element 9 enter the first case 5 from the discharge case portion 9b. It is configured.
The blow-by gas g entering the main body case 4 through the introduction opening 5a flows forward through the internal passage 17 and is discharged from the gas outlet 8 formed above the front end of the first case 5. . Note that 8a shown in FIGS. 5 and 6 is a sealing body such as a rubber ring.

The first case 5 has a front uppermost wall 5A having a gas outlet 8, an upper wall 5B on which the element case 9A is arranged, and a rear uppermost wall 5C. Nut portions 25 for fastening the element case 9A with bolts 22 are formed at the rear end of the front top wall 5A and the rear top wall 5C. The highest walls of the main body case 4 are the front and rear top walls 5A, 5C, and the highest wall of the oil separator A is the cover lid 18.

A pair of front and rear oil reservoirs 20, 21 are formed in the lower second case 6 and project downward, and oil outlets 20A, 21A with check valves 10 are provided at the lower ends of each oil reservoir 20, 21. is provided. Each of the oil reservoirs 20 and 21 extends downward in a stepwise manner so as to avoid the components of the valve train V. Therefore, each oil outlet 20A, 21A has an oil outlet 20A, 21A located within the height region of the valve train V while avoiding the components of the valve train V arranged below the internal passage 17. ing.

The oil components captured from the blow-by gas g moving through the internal passage 17 and the oil components flowing down from the element case 9A are transferred into the upper head cover 3 from the oil outlets 20A and 21A of the front and rear oil reservoirs 20 and 21 ( inside the engine). That is, at the lower end of each oil reservoir 20, 21, there is an oil outlet 20A located within the height region of the valve mechanism V while avoiding the components of the valve mechanism V disposed below the internal passage 17. , 21A.

Further, a bypass valve 16 that can be opened downward is provided at the rear end of the second case 6 of the element case 9A. When the internal pressure of the upper head cover 3 (the internal pressure inside the engine) reaches a predetermined pressure or higher, the bypass valve 16, which had been in the "closed" state, becomes the "open" state, and the gas flows through the internal passage 17 and the gas outlet part 8. It is configured to allow pressure to escape to the intake passage.

As shown in FIGS. 1, 2, and 3, the ceiling wall 3E of the upper head cover 3 is formed with a rib wall 23 extending downward from the ceiling inner surface 3e. The rib wall 23 includes a horizontal rib 23A extending rightward from the left inner surface 3c which is the inner surface of the left side wall 3C, and a rear inner surface which is bent 90 degrees rearward from the right end of the horizontal rib 23A and continues from the left inner surface 3c which is the inner surface of the left side wall 3C. 3b. A thick valve rib 24A having a downward opening 24 is formed on the inside of the ceiling wall 3E, continuing from the front side of the horizontal rib 23A.

The oil separator A is arranged so that the upper part of the element case 9A fits into the bottomless box-shaped space surrounded by the ceiling wall 3E, left side wall 3C, rear side wall 3B, horizontal ribs 23A, and vertical ribs 23B of the upper head cover 3. is bolted to the upper end of the lower head cover 2. As a result, the blow-by gas g flowing from the crankcase is spread across the width between the front, rear, left and right side walls 4A to 4D and ceiling wall 4E of the oil separator A and the front and rear left and right side walls 3A to 3D and ceiling wall 3E of the upper head cover 3. The air flows through the circulation spaces 11 to 15 (circulation space S), which are narrow spaces, to a large number of suction ports 18a.

As shown in FIGS. 1, 2, and 8, the front circulation space 11 is located between the front wall 4A of the main body case 4 (the front outer surface 4a) and the front wall 3A of the upper head cover 3 (the front inner surface 3a). , and a space between the front surface (not shown) of the element case 9A and the rear surface (not shown) of the horizontal rib 23A.
The rear circulation space 12 is a space between the rear wall 4B of the main body case 4 (the rear outer surface 4b) and the rear wall 3B of the upper head cover 3 (the rear inner surface 3b). (omitted) and the rear inner surface 3b.

The left circulation space 13 is a space between the left side wall 4C of the main body case 4 (left outer surface 4c) and the left side wall 3C of the upper head cover 3 (left inner surface 3c). (omitted) and the left inner surface 3c.
The right circulation space 14 is a space between the right side wall 4D of the main body case 4 (the right outer surface 4d) and the right side wall 3D of the upper head cover 3 (the right inner surface 3d). (omitted)) and the vertical rib 23B.

Further, the upper circulation space 15, which is the space between the upper and lower sides of the cover lid 18 (the upper surface of the cover lid 18) and the ceiling wall 3E of the upper head cover 3 (the inner surface of the ceiling 3e), is also a circulation space S (Fig. 6 (see Figure 9). In the case of an oil separator (not shown) in which the oil element 9 is installed inside the main body case 4, the ceiling wall 4E of the main body case 4 (top surface 4e) and the ceiling wall 3E of the upper head cover 3 ( The space between the top and bottom of the ceiling inner surface 3e) becomes the upper circulation space 15. In the structure shown in FIGS. 6 and 7, the upper surface of the cover lid 18 corresponds to the upper surface 4e of the oil separator A.

Next, the blow-by gas g in the head cover H rises through the front, rear, left and right circulation spaces 11 to 14 (sometimes passing through the upper circulation space 15), as shown by the arrows in FIGS. 1 and 2. The gas moves and enters the oil element 9 (into the element case 9A) through the gas introduction part 7, which is the inlet of the oil separator A, that is, the suction hole part 18a of the cover lid 18 (see FIG. 6). When the oil element 9 is moved from top to bottom, the oil component in the blow-by gas is captured, and the captured oil component and the blow-by gas g from which the oil component has been removed to some extent are transferred from the discharge case portion 9b to the first case 5. Flows into the internal passage 17 of the.

Even when the blow-by gas g flowing downward changes its direction forward in order to move forward in the internal passage 17, the oil component does not bend and moves downward and is captured (inertia force separation effect), and the captured oil The components are discharged into the head cover H from two oil reservoirs 20 and 21 at the front and rear. The blow-by gas g moving forward through the internal passage 17 changes its direction upward at the front end of the main body case 4 and is discharged to the outside of the oil separator A from the gas outlet section 8 . Even when changing direction from forward movement to upward movement, the effect of separating and capturing oil components from the blow-by gas g due to the inertial force separation effect can be expected.

The blow-by gas g coming out of the gas outlet part 8 passes through a pressure regulating valve 26 provided on the ceiling wall 3E of the upper head cover 3, and then passes through a dedicated reduction passage 27 (see FIG. 4) such as a hose pipe to the intake passage C. It is designed to flow. As shown in FIG. 4, a specific example of the intake passage C is an air supply section 28A of a supercharger (turbo) 28, and the end of the return passage 27 is joined to the air supply section 28A.

As explained above, the oil separator A is configured to guide the blow-by gas g to the intake passage C after passing through the inside of the head cover H, and the oil separator A that captures and removes oil from the blow-by gas g is provided inside the head cover H. A gas introduction section 7, which is an inlet for the blow-by gas g in the separator A, is provided at the upper end of the oil separator A.

That is, the blow-by gas g moving upward within the head cover H moves upward through the front, rear, left and right circulation spaces 11 to 14 and the upper circulation space 15, and then moves upward through the suction hole which is the gas introduction section 7 of the oil separator A. 18a (see FIG. 6). Therefore, compared to a structure in which the gas introduction part is provided on the side or below the oil separator, the travel distance to reach the oil separator can be easily increased without increasing the size of the head cover, and there is also an opportunity to capture oil components. can be increased. Of course, compared to the case where the oil separator is provided outside the engine, there is also the advantage that the oil separator and external piping are cooled and the risk of water freezing is reduced or eliminated.

Blow-by gas from the crankcase is configured to flow to the gas introduction section 7 through a circulation space S (front, rear, left and right circulation spaces 11 to 14) sandwiched between the inner surface of the head cover H and the outer surface of the oil separator A. Therefore, even though the gas introduction part 7 is arranged in the narrow space (upper flow space 15) between the oil separator A and the ceiling wall 3E of the head cover H, a sufficient flow of blow-by gas g (unit area It has the advantage of being able to obtain a higher flow rate (per unit flow rate).

Since the gas inlet 9G (suction hole portion 18a: see FIG. 6) of the oil element 9 is configured to serve as the gas introduction portion 7 of the oil separator A, the configuration is improved compared to the case where they exist separately. A streamlined structure that allows for dual use and compactness has been realized. Further, since the element case 9A is bolted to the main body case 4 from above, there is an advantage that only the oil element 9 can be replaced or removed for maintenance.

In the oil separator A, an internal passage 17 that occupies most of the internal volume is provided below the oil element 9 and the gas outlet part 8, both of which are arranged at the upper part. There is an advantage that increasing the number of changes (downward→forward, forward→upward) makes it easier to obtain the effect of trapping oil components through inertial separation.

Since the gas inlet 9g (gas introduction part 7) has a wide area due to the large number of suction holes 18a formed in the cover lid 18, efficiency can be increased from the upper circulation space 15 by the ceiling surface 3e and the upper surface of the cover lid 18. The blow-by gas g can be caused to flow into the oil element 9 well and smoothly. The blow-by gas g that has traveled a long distance to the top of the interior of the head cover 2 is changed direction at the gas inlet 9g, which has the advantage of being expected to trap oil components through inertial separation.

In addition, since oil outlets 20A and 21A located within the height region of the valve train V are formed at the lower end of each oil reservoir 20 and 21, the space inside the head cover H can be efficiently used as an oil separator. It can be used to increase the volume of A, and there is also the advantage that the captured oil can be returned to the engine while being used to lubricate the valve mechanism V.

[Another embodiment]
(1) A head cover structure may be used in which the opening area of the oil separator A as the gas introduction portion 7 is expanded, such as by omitting the cover lid 18. Further, the oil element 9 may include an oil separator that is housed in the main body case 4.

(2) As suggested in FIG. 8, by arranging the non-porous plate-shaped cover lid 18 and the main body case part 9a with a slight vertical separation, a horizontal introduction slit is opened all around the front, back, left, and right. The oil separator A may have an oil element 9 having a structure in which an oil element 19 is formed. In this structure, the blow-by gas g flowing to the ceiling inside the upper head cover 3 enters the element case 9A through the introduction slit 19 which becomes the gas introduction port 7.

In other words, since the gas introduction part 7 is configured as an introduction slit 19 which is a circumferential space between the element case 9A and the cover lid 18, the blow-by gas g enters the gas inlet 9G (gas introduction part 7) sideways. There will be an influx of people. Therefore, the blow-by gas g that has entered the gas introduction section 7 is changed in its course from sideways to downward, and there is an advantage in that the oil component can be captured by inertial separation at the gas inlet 9G as well.

3a to 3d Inner surface of side wall 3e Inner surface of ceiling wall 4a to 4d Side surface 4e Top surface 7 Gas introduction part 8 Gas outlet part 9 Oil filter 9G Gas inlet 11 to 15 Space part 17 Internal passage 18 Plate body 20, 21 Oil reservoir part 20A , 21A Oil outlet A Oil separator C Intake passage H Head cover S Distribution space V Valve mechanism

Claims (9)

It is configured to guide blow-by gas through the inside of the head cover and then into the intake passage.
An oil separator that captures and removes oil from blow-by gas is provided inside the head cover,
A head cover structure in which a gas introduction portion, which is an inlet for blow-by gas in the oil separator, is provided at an upper end portion of the oil separator. 2. The head cover structure according to claim 1, wherein blow-by gas from the crankcase flows to the gas introduction section through a circulation space sandwiched between the inner surface of the head cover and the outer surface of the oil separator. The circulation space includes a space between the inner surface of the ceiling wall of the head cover and the upper surface of the oil separator, and/or a space between the inner surface of the side wall of the head cover and the side surface of the oil separator. The head cover structure according to claim 2. 4. The head cover structure according to claim 1, wherein the oil filter included in the oil separator is provided with a gas inlet serving as the gas introduction section. 5. The head cover structure according to claim 4, wherein an internal passage is provided below the oil filter to send the blow-by gas discharged from the oil filter to a gas outlet section which is an outlet of the blow-by gas in the oil separator. 6. The head cover structure according to claim 5, wherein the gas outlet portion is provided at a side of the oil filter so as to open upward from the oil separator. 7. The head cover structure according to claim 6, wherein the gas outlet portion is arranged in line with the oil filter in a cylinder serial direction. Any one of claims 1 to 3 and 5 to 7, wherein a plate-like body is provided to cover an upper surface side of the gas introduction part so that blow-by gas flows into the gas introduction part from the lateral side thereof. The head cover structure described in . An oil reservoir projecting downward from the oil separator is formed, and a lower end of the oil reservoir has a height of the valve mechanism in a state that avoids components of the valve mechanism disposed below the internal passage. Head cover structure according to any one of claims 5 to 7, comprising an oil outlet located within the area.

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