JP2018003629A - Industrial engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial engine improved to minimize problems such as freezing, degradation of a blow-by function caused by freezing, and oil leakage under a low temperature by installing an oil separator of an externally mounted structure and its pair of supply/exhaust pipes in a state of being hardly frozen.SOLUTION: In an industrial engine having an oil separator S for capturing a liquid component in a blow-by gas guided to an intake passage through an inner path of a head cover 3, the oil separator S is installed at an exhaust side of a cylinder head in a state of being positioned higher than the head cover 3, the oil separator S is communicated and connected to the cover inner paths 3A, 3B by using a pair of supply/exhaust pipes 14, 15 taken out from a side wall 3S at an exhaust side, of the head cover 3, and heat shielding members 27 are respectively disposed between each of pipe basic end portions 14f, 15f at the head cover side, of the pair of supply/exhaust pipes 14, 15 and an exhaust manifold 25.SELECTED DRAWING: Figure 11

Description

  The present invention relates to industrial engines such as agricultural machinery engines, construction machinery engines, and generator engines. Specifically, blow-by gas in a crankcase is introduced into an intake passage through a passage in a cover formed in a head cover. The present invention relates to an industrial engine equipped with an oil separator that guides and captures a liquid component in blow-by gas.

  Blow-by gas refers to a mixture or combustion gas in a combustion chamber of an internal combustion engine that has leaked into the crankcase from the gap between the piston and the cylinder (specifically, the gap between the piston ring and the cylinder). That is, unburned gas and exhaust gas, and what is called oil mist in which these are mixed with oil are also included. When this blow-by gas enters the crankcase, it causes engine oil deterioration, metal corrosion, and air pollution.

  Therefore, it is a common practice to provide a mechanism that recirculates the blow-by gas accumulated in the crankcase to the intake passage, mixes it with a new air-fuel mixture, burns it, and does not release the air as it is, that is, a blow-by gas reduction device. ing. The blow-by gas reduction device is provided with an oil separator (also referred to as a filter) for capturing liquid components such as oil and water in the blow-by gas and returning the captured liquid components into the crankcase.

  As this type of blow-by gas reduction device and oil separator, for example, those disclosed in Patent Document 1 are known. In the technique disclosed in Patent Document 1, a blow-by gas is sucked from a head cover chamber (17c) communicated with a crankcase, and a liquid component is removed through two separators (filters: 21, 22). Reduced to The oil separated and trapped by the filtering action of these separators (filters: 21 and 22) passes through the drain pipe (23) having a check valve at the top from the bottom of the filter case, and is pulled into the crankcase (16) by gravity. It is configured to return to

When the separator is externally mounted on the engine as an independent part, it is convenient that a sufficient separator capacity can be secured. However, because of the external structure, there is a weak surface at low temperatures. For example, in a low-temperature situation such as below freezing in winter, moisture contained in blow-by gas may freeze in the separator and its supply / discharge pipe, leading to clogging.
When clogged due to moisture freezing, not only the blow-by reduction function does not operate normally, but also the blow-by path is blocked, the crankcase internal pressure increases, and unexpected oil leakage may occur.

JP 2007-247448 A

  The object of the present invention is to install the oil separator and supply / exhaust pipe in a state where it is difficult to freeze as much as possible when adopting the external structure of the oil separator, freeze at low temperature, blow-by function deterioration due to freezing, oil leakage, etc. It is the point which provides the industrial engine improved so that the inconvenience of this may not arise as much as possible.

The invention according to claim 1 is an oil separator that guides the blow-by gas in the crankcase 1B to the intake passage 9 through the in-cover passages 3A and 3B formed in the head cover 3 and captures the liquid component in the blow-by gas. For industrial engines equipped with S,
The oil separator S is disposed on the exhaust side of the cylinder head 2 in a state of being higher than the head cover 3.
The oil separator S is communicatively connected to the in-cover paths 3A, 3B using a pair of supply / exhaust pipes 14, 15 taken out from the side wall 3S on the exhaust side of the head cover 3.
A heat shield member 27 is interposed between the pipe base end portions 14f and 15f on the head cover side of each of the pair of supply and discharge pipes 14 and 15 and the exhaust manifold 25.

The invention according to claim 2 is the industrial engine according to claim 1,
The heat shield member 27 is interposed between the exhaust cover 26 surrounding the exhaust manifold and the pipe base end portions 14f and 15f.

The invention according to claim 3 is the industrial engine according to claim 2,
The heat shield member 27 is attached by screwing means 36 for attaching the exhaust cover 26 to the exhaust manifold 25 together.

The invention according to claim 4 is the industrial engine according to any one of claims 1 to 3,
The heat shield body 27A located immediately below the pipe base ends 14f and 15f in the heat shield member 27 is as close as possible to the pipe base ends 14f and 15f.

The invention according to claim 5 is the industrial engine according to claim 4,
The heat shield main body 27A is formed with a partition plate portion 27B positioned between the exhaust pipe 35 standing from the exhaust manifold 25 and the pipe base end portions 14f, 15f. .

The invention according to claim 6 is the industrial engine according to claim 4 or 5,
One or a plurality of holes 27a for adjusting the heat shielding action are formed in the heat shielding main body 27A.

The invention according to claim 7 is the industrial engine according to any one of claims 1 to 6,
On the upper surface of the exhaust cover 26, an opening 26a for avoiding an exhaust flange 25A provided with an outlet opening 25a in the exhaust manifold 25 is formed.
The heat insulating member 27 is formed with an opening cover portion 27F that covers a portion of the opening portion 26a between the exhaust flange 25A and the cylinder head 2.

The invention according to claim 8 is the industrial engine according to any one of claims 1 to 7,
The heat shielding member 27 is made of a bent steel sheet material.

  According to the first aspect of the present invention, the oil separator and the pair of supply / exhaust pipes are prevented from freezing and clogging due to this while preventing the base end side of the supply / exhaust pipe from being overheated by the exhaust heat. An effect can be obtained.

Even if moisture contained in the blow-by gas is present in the separator or the supply / discharge pipe, it stays in the separator or the supply / discharge pipe so that it is returned to the crankcase or flows through the supply / discharge pipe and moves to the head cover. It will be avoided. Therefore, even in an extremely cold state such as below freezing point, it is possible to regulate that moisture does not freeze and become clogged in the separator and the supply / discharge pipe.
In addition, of the pair of supply and discharge pipes, the pipe base end portion on the head cover side is in a positional relationship closer to the exhaust manifold than the other pipe portions, and may be heated more than expected. Therefore, since the heat shield member is provided between the pipe base end and the exhaust manifold, the entire supply and exhaust pipe can be appropriately heated without overheating the pipe base end. By providing the heat shielding member, in addition to the heat shielding effect, a convection prevention effect can be obtained.

As a result, when an external structure of the oil separator is adopted, the oil separator and the supply / discharge pipe are installed in a state where it is difficult to freeze as much as possible. An industrial engine improved so as not to occur as much as possible can be provided.
In this case, as in the second aspect of the invention, if a heat shield member is interposed between the exhaust cover surrounding the exhaust manifold and the pipe base end portion, more appropriate heat shield can be performed.

  According to the third aspect of the present invention, since the heat shield member is attached together by the screwing means for attaching the exhaust cover to the exhaust manifold, it is advantageous in that the number of parts can be reduced and the cost can be reduced.

  According to invention of Claim 4, the following effects are acquired. That is, if the heat shield body is set near the exhaust manifold between the upper and lower sides of the pipe base end and the exhaust manifold, the radiant heat easily flows into the upper space of the heat shield body and the heat shield action is not good. Therefore, there is an advantage that the heat shielding action can be clearly obtained by providing the heat shield body as close to the pipe base end as possible.

  According to the invention of claim 5, with respect to the radiant heat given to the pipe base end portion from the exhaust pipe standing upright from the exhaust manifold, a new heat shielding component is provided by the partition plate portion formed in the heat shielding body. There is an advantage that it can be rationally regulated without providing it.

  According to the sixth aspect of the present invention, the amount of radiant heat from the exhaust manifold can be finely adjusted by a simple structural device in which an appropriate number of holes are provided in the heat shield body, and the supply and exhaust pipe can enjoy the radiant heat as uniform as possible as a whole. There is an effect that can contribute.

  According to the seventh aspect of the present invention, the head cover side portion of the opening portion of the exhaust cover can be covered by the opening cover portion formed in the heat shield member, and it is multifunctional and rational while being a single component. An industrial engine in which a typical structure is realized can be provided.

  According to the eighth aspect of the present invention, there is an advantage that the heat shield member can be configured easily, lightly and inexpensively by one bent steel plate.

Front view showing engine with oil separator Left side view of the engine of FIG. Plan view of the engine of FIG. Right side view of the engine of FIG. 1 is an overall perspective view of the engine shown in FIG. Schematic schematic showing blowby gas recirculation structure Side view of partially cutout cylinder head cover Plan view of cylinder head cover Bottom view of partially cutout cylinder head cover Enlarged front view of oil separator Perspective view of the main part viewed from the upper right diagonally showing the vicinity of the exhaust manifold Top view showing the heat shield and the structure around it Side view showing heat shield and surrounding structure Rear view of heat shield plate showing positional relationship with supply / exhaust pipe and exhaust pipe

  Hereinafter, an embodiment of an industrial engine according to the present invention will be described as an example of a spark ignition type vertical multi-cylinder engine used for an agricultural tractor or the like with reference to the drawings. Hereinafter, the side on which the engine cooling fan 6 is installed in the crankshaft direction is defined as the front, the opposite side is defined as the rear, the intake manifold 8 side is defined as the left, and the exhaust manifold 25 side is defined as the right.

  As shown in FIGS. 1 to 5, in this engine, a cylinder head 2 is assembled to the upper part of a cylinder block 1, and a cylinder head cover (hereinafter simply referred to as a head cover) 3 is assembled to the upper part of the cylinder head 2. The oil pan 4 is assembled to the lower part of the cylinder block 1. A transmission case 5 is assembled at the front end of the cylinder block 1, an engine cooling fan 6 is disposed at the front of the transmission case 5, and a flywheel or flywheel housing 7 is disposed at the rear of the cylinder block 1. The upper half part of the cylinder block 1 is constituted by the cylinder part 1A, and the lower half part is constituted by the crankcase 1B.

  An intake manifold 8 is arranged on one side, for example, the left side of the cylinder head 2, a throttle valve 10 is attached to the front portion of the main pipe 9 of the intake manifold 8, and a gas mixer 11 is attached to the front portion of the throttle valve 10. An air cleaner (not shown) communicates with the gas mixer 11. The main pipe 9 of the intake manifold 8 is, for example, a rectangular column-shaped pipe that is long in the front-rear direction, which is the direction of the axis P of the crankshaft, and a branch pipe 30 that distributes intake air from the main pipe 9 to the intake port of each cylinder. The number of cylinders (four) is derived. Reference numeral 28 denotes an alternator, and 29 denotes an adjustment arm for adjusting the position of the alternator 28.

  As shown in FIGS. 5 and 11, an exhaust manifold 25 and an exhaust cover 26 that covers the exhaust manifold 25 are arranged on one side, for example, the right side of the cylinder head 2. A single exhaust flange 25 </ b> A having an upward outlet opening 25 a of the exhaust manifold 25 is provided, and the exhaust flange 25 </ b> A is located in a notch-shaped opening 26 a of the exhaust cover 26. The opening 26 a is provided on the rear upper surface side of the exhaust cover 26.

  As shown in FIGS. 3 and 5, a PCV valve 12 is integrally provided on the upper portion of the head cover 3, and the main pipe 9 of the intake manifold 8 which is a downstream side passage of the throttle valve 10 in the air supply path, The PCV valve 12 is connected in communication by a blow-by gas pipe 20. Further, the gas mixer 11 and the upper part of the head cover 3 are connected in communication via a fresh air introducing tube 13. The intake manifold 8 and the main pipe 9 are examples of the intake path.

  Next, the blowby gas recirculation structure in this engine will be described. As shown in FIG. 6, the engine E is provided with a blowby gas passage W that can guide the blowby gas in the crankcase 1 </ b> B from the inside of the head cover 3 to the downstream passage of the throttle valve 10 through the PCV valve 12. Yes. The blow-by gas passage W returns the blow-by gas generated inside the crankcase 1B to the main pipe 9 through the inside of the head cover 3, the external oil separator S, the inside of the head cover 3, and the PCV valve 12 in this order. For each passage.

  As shown in FIG. 6, the inside of the head cover 3 is partitioned by a partition wall 3 </ b> W into a cover one end side chamber 3 </ b> A communicating with the crankcase 1 </ b> B and a cover other end side chamber 3 </ b> B communicating with the PCV valve 12. An oil separator S (see FIGS. 5 and 10) having a gas inlet 14A communicating with the cover one end side chamber 3A and a gas outlet 15A communicating with the cover other end side chamber 3B uses a pair of supply and discharge pipes 14 and 15. The head cover 3 is provided separately.

  Here, the cover one end side chamber (an example of a cover internal path) 3A is the inside of the head cover 3 and the flywheel housing 7 side (rear side) in the direction of the crankshaft (not shown) that is the axis of the flywheel. It is a part. The cover other end side chamber (an example of an in-cover path) 3B is a portion on the engine cooling fan 6 side (front side) in the direction of the crankshaft center (not shown) in the head cover 3. The crank shaft center (not shown) is parallel to the shaft center P of the engine cooling fan 6 described later.

  A filter 16 acting on the blow-by gas is disposed on the downstream side in the blow-by gas flow direction with respect to the communication portion with the oil separator S in the cover other end side chamber 3B to capture and remove engine oil. Further, a tube-made oil return path 17 for returning the oil captured by the oil separator S to the inside of the crankcase 1B is provided.

  The head cover 3 has a bottomless box-like shape and is integrally disposed on the cylinder head 2 as shown in FIGS. 7 to 9, and the interior space of the cover is an upper and lower partition that is bolted. The plate 18 partitions the lower space 3K and the upper space 3U. Only the lower space 3K and the upper space 3U are communicated with each other by a notch portion 19 formed at the flywheel housing 7 side end of the upper and lower partition plates 18.

  The upper space 3U is divided into a cover one end side chamber 3A having a notch 19 and a cover other end side chamber 3B having a PCV valve 12 by a partition wall 3W located in the middle of the head cover 3 in the longitudinal direction. The partition wall 3W also serves as a structure for setting a filter 16 for removing mist-like engine oil from blow-by gas. A PCV valve 12 is provided on the downstream side in the blow-by gas flow direction of the oil separator S in the in-cover passages 3A and 3B.

  As shown in FIGS. 6, 7, and 9, a pipe material for connecting a supply-side supply / discharge pipe 14 is connected to the exhaust-side side wall 3 </ b> S of the head cover 3 near the partition wall 3 </ b> W in the cover one-end side chamber 3 </ b> A. A gas outlet 14B is provided. In the side wall 3S of the head cover 3 near the partition wall 3W in the cover other end side chamber 3B, a gas return port 15B made of a pipe material for connecting the discharge side supply / discharge pipe 15 is provided.

  As shown in FIGS. 3 and 6 to 8, the head cover 3 has a PCV valve 12 in communication with the upper part of the cover other end side chamber 3 </ b> B along the longitudinal direction of the head cover 3 and its discharge side pipe. 12a is mounted integrally by means such as a taper screw in a posture facing obliquely upward to the outside. Further, the connection pipe 21 to which the fresh air introducing tube 13 is fitted and connected is attached to the lower portion of the discharge side pipe 12a in the head cover 3 so as to cross the PCV valve 12 and to face obliquely upward. ing. Reference numeral 22 denotes a cap screwed into the engine oil supply port.

  As shown in FIGS. 1, 3 to 5, 10, and 11, the oil separator S is formed by using a sheet metal mounting bracket 23 at an end portion on the engine cooling fan side in the longitudinal direction of the head cover 3. 3 is provided as an independent part disposed at the exhaust manifold 25 side with respect to the head cover 3 at a height level slightly higher than 3. A supply-side supply / discharge pipe 14 that is connected to the in-cover path 3A is connected to the side of the upper end of the oil separator S, and a discharge-side supply / discharge pipe 14 that is connected to the cover-in-path 3B is directly below. The exhaust pipe 15 is taken out respectively.

  That is, the oil separator S mounted on the engine is positioned higher than the head cover 3 and the exhaust side of the cylinder head 2 so that the pair of supply and discharge pipes 14 and 15 are both lower on the head cover side than the separator side. (Right side) The oil separator S is disposed outside the rotation region of the engine cooling fan 6 in the axial center P direction of the engine cooling fan 6 and very close to the engine cooling fan 6 in the front-rear direction. The separator S is brought closer to the front side (cooling is on the fan 6 side) than the exhaust manifold 25 (exhaust cover 26) on the rear side (leeward side) of the cooling fan 6, and from the exhaust manifold 25 (exhaust cover 26) in the front-rear direction. Is also arranged close to the cooling fan 6.

  The mounting structure of the oil separator S will be described in detail. As shown in FIGS. 1 to 3, 10, and 11, the mounting bracket 23 is provided on the windproof portion 23 a at the tip for bolting and supporting the oil separator S from the front side, and on the engine cooling fan side (front side) of the cylinder head 2. It is arrange | positioned and is provided with the base end part 23c bolted to the front wall of the water flange 34 which accommodates the thermostat, and the intermediate part 23b which connects the wind-proof part 23a and the base end part 23c. In order to make the oil separator S as close to the engine cooling fan 6 as possible in the front-rear direction, it is reasonable to bolt the mounting bracket 23 to the water flange 34 located in front of the cylinder head 2 (head cover 3). . A cooling water pump 33 is disposed on the rear side of the engine cooling fan 6.

  The wind-proof part 23a has a triangular portion with a sharp point in front view and is formed in a size and shape that covers most of the projected area of the oil separator S, and acts almost on the oil separator S by blocking the cooling air. It is configured not to. The base end portion 23c has a shape that rises obliquely upward to the right so that the windproof portion 23a is lifted high and the oil separator S is disposed higher than the head cover 3. The intermediate portion 23b connects the windproof portion 23a and the base end portion 23c along the left-right direction in a front-rear posture so that the windproof portion 23a is in the rearward position.

The alternator 28 is positioned on a curved adjustment arm 29 pivotally supported by the engine such as the cylinder head 2 by using the arc-shaped elongated hole 29a so that the tension of the belt (fan belt: not shown) can be adjusted. It is bolted so that it can be adjusted. The adjustment arm 29 is made of a thick steel plate and has excellent strength.
The distal end portion of the mounting bracket 23 and the adjustment arm 29 are connected to each other by a connecting member 31 having one end bolted to the arc-shaped elongated hole 29a of the adjustment arm 29 and the other end bolted to the lower portion of the windproof portion 23a. They are connected and fixed to each other. Since the connecting member 31 is connected to the base end side of the long arc-shaped elongated hole 29a extending in the adjusting direction, the connecting member 31 can also be configured as a strength member while preventing the adjusting function of the alternator 28 from being hindered. .

  Since the oil separator S is lifted higher by the mounting bracket 23, a passage 32 for cooling air of the engine cooling fan 6 is formed between the oil separator S and the alternator 28 below the oil separator S. More specifically, most of the path 32 is a space portion surrounded by the mounting bracket 23, the adjustment arm 29, and the connecting member 31.

  In other words, the front end of the mounting bracket 23 and the adjustment arm 29 that can adjust and set the belt tension position of the alternator 28 are connected and fixed to each other using the connecting member 31 made of sheet metal, and the mounting bracket 23 is attached to the oil separator S. A windproof portion 23a for restricting the cooling air from the engine cooling fan 6 is formed. Further, the mounting bracket 23 is arranged and set so that a passage 32 for cooling air is secured below the oil separator S.

  An oil return path 17 is connected to the bottom (or bottom wall) 24 of the oil separator S to return engine oil captured in the oil separator S to the crankcase 1B using a tube. Although not shown, the oil separator S has a built-in filter for separating mist-like engine oil mixed in blow-by gas. The oil returns to the crankcase 1B through the oil return path 17.

  As shown in FIGS. 3 to 5, the supply / discharge pipe 14 on the supply side is substantially L-shaped, and is supplied to be externally connected to the gas outlet 14 </ b> B in a state where the oil separator side is inclined to be higher. It has a pipe base end portion 14f and a linear supply pipe tip end portion 14k that is externally connected to the gas inlet 14A in a horizontal posture. Accordingly, the supply / discharge pipe 14 on the supply side is arranged and set in a posture state in which the head cover 3 side is lower than the oil separator S side as a whole.

  As shown in FIG. 3 to FIG. 5 and FIG. 11, the discharge-side supply / discharge pipe 15 has a discharge pipe base end portion 15 f that is externally connected to the gas return port 15 </ b> B in a horizontal posture extending right to the right, A discharge pipe distal end portion 15k externally connected to the gas outlet 15A in a horizontal posture extending directly behind, and a vertical discharge pipe middle portion 15t connecting the discharge pipe base end portion 15f and the discharge pipe distal end portion 15k. Yes. Accordingly, the discharge-side supply / discharge pipe 15 is also arranged and set in a posture state in which the head cover 3 side is lower than the oil separator S side as a whole.

As shown in FIG. 3 to FIG. 5 and FIG. 11, the pair of supply / discharge pipes 14, 15 are both most except the end on the oil separator side, that is, the supply pipe tip 14 k and the discharge pipe tip 15 k. The remaining portions except for the end portions on the oil separator side are arranged in a state of passing over the exhaust cover 26 (exhaust manifold 25).
The supply pipe base end portion 14f, the discharge pipe base end portion 15f, and the discharge pipe middle portion 15t, that is, the portion of the pair of supply and discharge pipes 14 and 15 that are relatively close to the exhaust cover 26 in the vertical direction and the exhaust cover 26 Between the upper and lower sides, a sheet metal heat shield plate (an example of a heat shield member) 27 made of a bent steel sheet material is disposed.

As shown in FIGS. 3 to 5 and FIGS. 11 to 14, the heat shield plate 27 includes a heat shield body 27A, a partition plate portion 27B formed by bending a part of the heat shield body 27A upward, and a heat shield body 27A. The front leg portion 27C and the rear leg portion 27D that support the front and rear of the front leg portion 27C, the front mounting seat 27E that follows the front leg portion 27C, and the rear mounting seat 27F that follows the rear leg portion 27D are provided.
The rear mounting seat 27F is screwed to both the exhaust manifold 25 and the exhaust cover 26 to support the rear leg portion 27D, as well as the exhaust flange 25A and the head cover 3 in the opening 26a formed in the exhaust cover 26. It is also an opening cover part that closes the gap.

As shown in FIGS. 12 to 14, the partition plate portion 27 </ b> B is a member that is attached to the exhaust flange 25 </ b> A and is capable of restricting the radiant heat of the exhaust pipe 35 taken out upward from reaching the supply / exhaust pipes 14 and 15. It is inclined and arranged so as to extend from the front right to the rear left in plan view. The heat shield main body 27A is formed with an appropriate number, for example, three adjustment holes 27a for adjusting the heat shield effect.
That is, the heat shield member 27 is interposed between the exhaust cover 26 surrounding the exhaust manifold and the pipe base end portions 14f and 15f, and the bolt (screwing means) for attaching the exhaust cover 26 to the exhaust manifold 25. In this case, the cover upper wall 26 </ b> A is fastened together. Further, the heat shield body 27A located immediately below the pipe base end portions 14f and 15f is as close as possible to the pipe base end portions 14f and 15f in the vertical direction.

The pipe base end portions 14f and 15f of the supply and discharge pipes 14 and 15 taken out from the right side wall 3S on the exhaust side of the head cover 3 are lower in height than the other portions of the supply and discharge pipes 14 and 15. The vertical distance from the exhaust manifold 25 (exhaust cover 26) is shortened, and the radiant heat from the exhaust manifold 25 tends to reach too much. Therefore, the heat shield plate 27 is provided so that the heat shield body 27A is located near the lower portion of the supply pipe base end portion 14f and the discharge pipe base end portion 15f. When the heat shield main body 27A is set close to the exhaust cover 26, the radiant heat is likely to reach from the upper space of the heat shield main body 27A, so that the heat shield action is clearly obtained as close as possible to the pipe base end portions 14f and 15f. This is preferable.
Further, by providing the heat shield plate 27, the radiant heat of the exhaust cover 26 flows to the rear or right along the heat shield plate 27 by the cooling air, and the effect of preventing the convection of the hot air can be expected.

  Then, the amount of radiant heat from the exhaust manifold 25 can be finely adjusted by an appropriate number of adjustment holes 27a provided in the heat shield body 27A, so that the supply and exhaust pipes 14 and 15 can enjoy the radiant heat as uniform as possible as a whole. ing. In addition, the rear mounting seat 27F that is fastened to the cover upper wall 26A and the exhaust manifold 25 by bolts 36 also serves as an opening cover portion 27F that covers the opening portion 26a of the exhaust cover 26. Although it is a steel plate, a multi-functional and rational structure is realized.

  Even when the water contained in the blow-by gas is present in the oil separator S when the engine is stopped after the working machine is operated, the liquid component containing the water flows through the supply / discharge pipes 14 and 15 and flows into the head cover 3. Or flow through the oil return path 17 and into the crankcase 1B, so that at least water does not stagnate in the oil separator S. Therefore, even in extremely cold conditions such as below freezing, the effect of being regulated so as to prevent the inconvenience of moisture freezing and clogging in the oil separator S is exhibited.

  When the engine is stopped, the liquid component containing moisture in the pair of supply / discharge pipes 14 and 15 moves to the head cover 3 by the arrangement structure in which the head cover side is lower than the separator side of the supply / discharge pipes 14 and 15. Therefore, it is possible to prevent the supply and discharge pipes 14 and 15 from becoming clogged due to freezing. In addition, since the radiant heat of the exhaust manifold rises from the bottom of the supply / exhaust pipes 14, 15 and is warmed, even if the supply / exhaust pipes 14, 15 are slightly frozen, the engine starts. Due to the radiant heat of the exhaust manifold 25 that is quickly heated, there is an advantage that the ice melts at an early stage.

  As shown in FIGS. 1 and 10, the oil separator S is disposed outside the rotation region 6 r of the engine cooling fan 6 in the axial center P direction view (front-rear direction view) of the engine cooling fan 6. It is devised so that it is difficult to receive the cooling effect by the wind. In addition, as shown in FIGS. 3 to 5, the oil separator S disposed on the leeward side of the engine cooling fan 6 is as close as possible to the engine cooling fan 6 in the axial center P direction, so that the cooling air spreads. It is possible to arrange it outside the region or as much as possible. Therefore, the engine is arranged on the exhaust side so that the cooling air is not hit as much as possible, and the engine can effectively prevent the oil separator S from freezing without reducing the cooling action of the engine.

  Since the oil separator S is supported in a cantilevered manner by the mounting bracket 23, the oil separator S tends to be easily shaken such as easily resonating due to engine vibration. Therefore, in the present invention, the windproof portion 23a is connected and fixed to the adjustment arm 29 having sufficient strength existing below the oil separator S via the connecting member 31. Therefore, there is an advantage that the mounting bracket 23 can be reasonably close to a both-end support without providing a separate member, and the oil separator S is supported with sufficient strength with less vibration.

  The oil separator S on the exterior of the engine is provided on the exhaust manifold 25 side (on the right side of the engine E) with respect to the head cover 3 and includes a windproof portion 23a that restricts the hitting of the cooling air. The oil separator S receives the radiant heat of the exhaust, and is disposed in a temperature environment in which freezing or the like hardly occurs while having an external structure advantageous for capacity and oil capture. Since the passage 32 for the cooling air is secured below the oil separator S, there is an advantage that the air cooling action as a whole engine is sufficiently exhibited while the oil separator S is difficult to be hit by the air.

  As shown in FIG. 6, the blow-by gas in the crankcase 1B is notched 19 → cover one-end side chamber (in-cover path) 3A → supply-side supply / discharge pipe 14 → oil separator S → discharge-side supply. Exhaust pipe 15 → base end of cover other end side chamber 3B → filter 16 → end end of cover other end side chamber (inside cover path) 3B → PCV valve 12 → pipe 20 for blow-by gas → main pipe 9 (an example of intake path) The blow-by gas passage W returns to the downstream side of the throttle valve 10. The oil in the blow-by gas captured by the cover-incorporated filter 16 is configured to return into the crankcase 1B through a return path (not shown).

  Apart from the head cover 3 having the filter 16 inside, the oil separator S that is externally attached to the engine E, that is, the exterior, is provided as an independent component, so that the volume of the blow-by gas passage W can be made sufficient as a total. The filter area and volume can be sufficiently taken, and the liquid component in the blow-by gas mainly made of oil can be sufficiently removed. Note that the location of the filter 16 in the head cover 3 can be changed and set in various ways, and the filter 16 can be omitted.

Since the oil separator S is externally attached, it is necessary to provide the partition wall 3W, the gas outlet 14B, and the gas return port 15B, but it is not necessary to increase the size of the head cover 3 or to change the shape, so that it is economical and reasonable. The blow-by gas recirculation structure with enhanced functions can be realized.
When the blow-by gas is recirculated to the downstream side of the throttle valve 10 via the PCV valve 12, the main pipe 9 is at a negative pressure. Therefore, simply connecting the oil separator S causes a disadvantage that the oil mist is also recirculated. For example, measures such as providing a check valve in the oil return path 17 of the oil separator S are necessary.

  However, the interior of the head cover 3 is divided into front and rear, the oil separator S is connected in the middle of the gas passage inside the head cover 3, and the filter 16 that provides ventilation resistance is provided in the cover other end side chamber 3B. S is configured such that the negative pressure of the main pipe 9 hardly acts on S.

  Therefore, in the oil separator S, the oil captured in the oil separator S is simply returned to the crankcase 1B by natural fall by simply connecting the oil return path 17 to the bottom 24 without providing a check valve or the like. be able to. Since the filter 16 provided inside the head cover 3 is arranged downstream of the oil separator S in the blow-by gas flow direction, the oil trapping filter 16 can also function as a negative pressure canceling resistor, Economic and rational blow-by gas recirculation structure.

  A pair of supply / exhaust pipes 14 and 15 communicating the head cover 3 and the oil separator S are provided laterally from the head cover 3 by providing the gas outlet port 14B and the gas return port 15B sideways on the side wall 3S on the exhaust side of the head cover 3. It is configured to be taken out. Therefore, the space on the side of the engine E can be effectively used as an installation space for the oil separator S, and the oil separator S that contributes to an increase in capacity can be attached without increasing or hardly increasing the height of the engine E. There are advantages.

[Another embodiment]
The heat shielding member 27 can be variously changed and set such as a sheet metal, a metal by casting or forging, and a heat-resistant synthetic resin plate. Further, the heat shield member 27 may be bolted to the exhaust cover 26 or the exhaust manifold 25 with a heat insulating material interposed therebetween.

1B Crankcase 2 Cylinder head 3 Head cover 3A, 3B Cover internal path 3S Exhaust side sidewall 9 Intake path 14, 15 Supply / exhaust pipe 14f, 15f Pipe base end 25 Exhaust manifold 25A Exhaust flange 25a Outlet opening 26 Exhaust cover 26a Opening 27 heat shield member 27A heat shield body 27B partition plate portion 27F opening cover portion 27a hole 35 exhaust pipe 36 screwing means S oil separator

Claims (8)

An industrial engine equipped with an oil separator that guides the blow-by gas in the crankcase to the intake path through the in-cover path formed in the head cover and captures liquid components in the blow-by gas,
The oil separator is disposed on the exhaust side of the cylinder head in a state of being higher than the head cover,
The oil separator is connected in communication with the path in the cover using a pair of supply / discharge pipes taken out from the exhaust-side side wall of the head cover,
An industrial engine in which a heat shield member is interposed between a pipe base end portion on the head cover side of each of the pair of supply / discharge pipes and an exhaust manifold.   The industrial engine according to claim 1, wherein the heat shield member is interposed between an exhaust cover that surrounds the exhaust manifold and the pipe base end portion.   The industrial engine according to claim 2, wherein the heat shielding member is attached together by screwing means for attaching the exhaust cover to the exhaust manifold.   The industrial engine according to any one of claims 1 to 3, wherein the heat shield body located immediately below the pipe base end portion of the heat shield member is as close as possible to the pipe base end portion.   The industrial engine according to claim 4, wherein the heat shield main body is formed with a partition plate portion positioned between an exhaust pipe standing from the exhaust manifold and the pipe base end portion.   The industrial engine according to claim 4 or 5, wherein the heat shield main body has one or more holes for adjusting a heat shield effect. On the upper surface of the exhaust cover, an opening for avoiding an exhaust flange having an outlet opening in the exhaust manifold is formed,
The industrial engine according to any one of claims 1 to 6, wherein an opening cover portion that covers a portion of the opening portion between the exhaust flange and the cylinder head is formed on the heat shield member.   The industrial engine according to any one of claims 1 to 7, wherein the heat shield member is made of a bent sheet of steel.

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