JP6621712B2 - Engine with blow-by gas recirculation device - Google Patents

Description

  The present invention relates to an engine with an oil separator such as an industrial engine. More specifically, the present invention guides blow-by gas in a crankcase to an intake passage through a passage in a cover formed in a head cover, and liquid components in the blow-by gas. The present invention relates to an engine with an oil separator that is equipped with an oil separator that captures oil.

  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 the inside of the crankcase (16) by gravity. It is configured to return to

  In the case where the separator is provided outside the engine as an independent part, it is convenient that a sufficient separator capacity can be secured, but on the other hand, there is a weak surface at low temperatures due to the external structure. For example, the water inside the separator may freeze in a cryogenic condition below freezing, such as in winter Hokkaido or the North American continent.

  When the engine is started up and used in a frozen state, the filter media of the separator is clogged until it is released from freezing. This may cause inconveniences such as an unexpected oil leak.

JP 2007-247448 A

  An object of the present invention is to provide an engine with an oil separator which is improved so that the inconvenience of freezing at low temperatures is prevented as much as possible by installing an oil separator with an external structure outside the engine in a state where it is hard to freeze as much as possible. It is in.

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. In an engine with an oil separator equipped with S,
The oil separator S is provided outside the head cover 3 as a component connected to the in-cover paths 3A, 3B via a pair of supply / discharge pipes 14, 15;
The oil separator S is disposed at a position higher than the head cover 3 and on the exhaust side of the cylinder head 2 such that the pair of supply / discharge pipes 14 and 15 are both lower on the head cover 3 side than the oil separator S side. It is,
The pair of supply / discharge pipes 14 and 15 are arranged so as to pass above the exhaust manifold 25 .

The invention according to claim 2 is the engine with an oil separator according to claim 1,
The oil separator S is arranged outside the rotation region of the engine cooling fan 6 as viewed in the direction of the axis P of the engine cooling fan 6 .

The invention according to claim 3 is the engine with an oil separator according to claim 2 ,
The oil separator S is arranged close to the engine cooling fan 6 on the leeward side of the engine cooling fan 6 .

The invention according to claim 4 is the engine with an oil separator according to any one of claims 1 to 3 ,
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 .

The invention according to claim 5 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. In an engine with an oil separator equipped with S,
The oil separator S is provided outside the head cover 3 as a component connected to the in-cover paths 3A, 3B via a pair of supply / discharge pipes 14, 15;
The oil separator S is disposed at a position higher than the head cover 3 and on the exhaust side of the cylinder head 2 such that the pair of supply / discharge pipes 14 and 15 are both lower on the head cover 3 side than the oil separator S side. And
The oil separator S is disposed outside the rotation region of the engine cooling fan 6 as viewed in the direction of the axis P of the engine cooling fan 6.
The oil separator S is arranged close to the engine cooling fan 6 on the leeward side of the engine cooling fan 6 .

According to the present invention, 5, such as in the time after stopping the engine operation, even moisture contained in the blow-by gas is present in the separator, or is returned to the crankcase, or water The contained liquid component flows through the supply / discharge pipe and moves into the head cover, so that it is avoided that the moisture stays in the separator. Therefore, even in an extremely cold state such as below freezing point, an effect of being regulated so that moisture does not freeze and become clogged in the separator is exhibited.

Even if liquid components containing moisture remain in the pair of supply / discharge pipes, the supply / discharge pipes move to the head cover due to the arrangement structure in which the head cover side is lowered. Is also prevented in advance. In addition, since the separator is disposed on the exhaust side and the radiant heat of the exhaust pipe, which is at a high temperature, is easily reached, the possibility of freezing at a low temperature can be minimized.
As a result, it is possible to provide an engine with an oil separator that is improved so that the inconvenience of freezing at low temperatures does not occur as much as possible by installing an oil separator having an external structure outside the engine in a state where it is hard to freeze.

According to the first aspect of the present invention, since the pair of supply / exhaust pipes are arranged above the exhaust manifold, the radiant heat of the exhaust manifold rises and the supply / exhaust pipe is easily heated. Therefore, even if a slight freezing has occurred in the supply / discharge pipe, the freezing is quickly released by the radiant heat of the exhaust manifold that is quickly heated as the engine is started. Accordingly, it is possible to provide a preferable engine with an oil separator that is unlikely to cause a problem that the blow-by gas path in the supply / exhaust pipe is clogged and that can be quickly released even if it occurs.

According to the second and fifth aspects of the invention, since the oil separator is disposed outside the rotation region as viewed in the axial direction of the engine cooling fan, it is difficult to receive an air cooling action by the cooling air. That is, there is an advantage that the possibility of freezing due to the air cooling action of the engine cooling fan hardly occurs due to the arrangement of the separator. In this case, as in the invention of claim 3 and 5, when the separator is in the leeward side of the engine cooling fan, by as much as possible close to the engine cooling fan can be arranged as much as possible separator outside air cooling action area, wherein The said effect by invention of claim | item 2 can be strengthened.

According to the fourth aspect of the present invention, since the PCV valve is provided on the downstream side of the oil separator in the blow-by gas flow direction in the in-cover path, the following effects are obtained.
When blow-by gas is returned to the intake system via the PCV valve, the intake path is at a negative pressure. If an oil separator is simply connected, the oil mist will also be recirculated. Measures such as providing a stop valve are required.

  However, the negative pressure of the intake path hardly acts on the oil separator by providing a separator as an exterior part in the middle of the path in the cover and additionally providing a supply / discharge pipe. Therefore, in an oil separator, a liquid component such as oil trapped in the oil separator is returned to the crankcase by natural fall by simply connecting an oil return path to the bottom without providing a check valve. The advantage that it can be obtained can be obtained.

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

  Hereinafter, an embodiment of an engine with an oil separator according to the present invention will be described as an example of a vertical spark ignition type in-line multiple cylinder industrial engine used in agricultural tractors and 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 a support stay 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.

  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 part 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 end of the upper and lower partition plates 18 on the flywheel housing 7 side.

  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 paths 3A and 3B.

  As shown in FIGS. 6, 7, and 9, a gas extraction made of a pipe material for connecting a supply-side supply / discharge pipe 14 to the 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 mouth 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 portion 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 introduction 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 intersect the PCV valve 12 and to face obliquely upward. Yes. 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 and provided as an independent part disposed on the exhaust manifold 25 side with respect to the head cover 3 (cylinder head 2) 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 mounted on the engine is positioned higher than the head cover 3 so that the pair of supply and discharge pipes 14 and 15 are not inclined so that the head cover side is higher and the head cover 3 side is lower than the separator S side. And it is attached to the exhaust side (right side) of the cylinder head 2. 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 close to the engine cooling fan 6 on the leeward side of the engine cooling fan 6. .
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.

  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. It 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 heat shield plate 27 made of sheet metal is arranged.

As shown in FIGS. 5 and 11, 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 front leg that supports the front and rear of the heat shield body 27A. A front mounting seat 27E following the front leg portion 27C and a rear mounting seat 27F following 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 also functions as a shielding member that closes the gap. 3 and 4, the heat shield plate 27 is omitted.

The partition plate portion 27B is a member that can restrict the radiant heat of the exhaust pipe (not shown) attached to the exhaust flange 25A and taken out upward from reaching the supply / exhaust pipes 14 and 15, and in front view Is inclined so as to extend from left to right. An appropriate number (1 to 3) of through holes 27a for adjusting the degree of heat insulation are formed in the heat insulation main body 27A. 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 a convection preventing effect of hot air can be expected.
In this way, the oil separator S is mounted at a position higher than the head cover 3 and on 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 3 side than the separator S side. It has been.

  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.

  As 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 of the supply / discharge pipes 14 and 15 is lowered. Therefore, it is possible to prevent the supply and discharge pipes 14 and 15 from being 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 can be arranged outside the region or as much as possible, and also from this point, it is devised so that the temperature lowering effect by the cooling air is not easily received.

  As shown in FIG. 6, the blow-by gas in the crankcase 1 </ b> B is notched 19 → cover one-end side chamber (in-cover path) 3 </ b> A → supply-side supply / discharge pipe 14 → oil separator S → discharge-side supply / discharge pipe. 15 → base end of cover other end side chamber 3B → filter 16 → tip end of cover other end side chamber (in-cover path) 3B → PCV valve 12 → blowby gas piping 20 → main pipe 9 (an example of intake path) The 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 a 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 disposed 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 / discharge pipes 14 and 15 communicating with the head cover 3 and the oil separator S are taken out from the head cover 3 in the lateral direction by providing the gas outlet 14B and the gas return port 15B in the side wall 3S of the head cover 3 sideways. It is configured. 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]
In the pair of supply / discharge pipes 14 and 15, the height of the oil separator S side end (gas inlet 14A, gas outlet 15A) is low, and the height of the head cover 3 side end (gas extraction port 14B, gas return port 15B) is low. An inclined pipe with an angle may be configured as described above.

1B Crankcase 2 Cylinder head 3 Head cover 3A, 3B Cover path 6 Engine cooling fan 6r Rotating area 12 PCV valve 14 Supply / discharge pipe 15 Supply / discharge pipe 25 Discharge manifold P Exhaust manifold P Engine cooling fan shaft S S Oil Separator

Claims (5)

An engine with an oil separator that is 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 the liquid component in the blow-by gas,
The oil separator is provided outside the head cover as a component connected to the in-cover path via a pair of supply / discharge pipes,
The oil separator is disposed at a position higher than the head cover and on the exhaust side of the cylinder head so that both the pair of supply and discharge pipes are lower on the head cover side than the oil separator side ,
An engine with an oil separator in which the pair of supply / discharge pipes are arranged so as to pass above the exhaust manifold . The engine with an oil separator according to claim 1, wherein the oil separator is disposed outside a rotation region of the engine cooling fan when viewed in the axial direction of the engine cooling fan . The engine with an oil separator according to claim 2 , wherein the oil separator is disposed adjacent to the engine cooling fan on a leeward side of the engine cooling fan . The engine with an oil separator according to any one of claims 1 to 3, wherein a PCV valve is provided on the downstream side in the blow-by gas flow direction of the oil separator in the in-cover path . An engine with an oil separator that is 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 the liquid component in the blow-by gas,
The oil separator is provided outside the head cover as a component connected to the in-cover path via a pair of supply / discharge pipes,
The oil separator is disposed at a position higher than the head cover and on the exhaust side of the cylinder head so that both the pair of supply and discharge pipes are lower on the head cover side than the oil separator side,
The oil separator is disposed outside the rotation region of the engine cooling fan in the axial direction of the engine cooling fan,
The oil separator is an engine with an oil separator disposed on the leeward side of the engine cooling fan in the vicinity of the engine cooling fan .

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