JP7498387B2 - BLOW-BY GAS SUPPLY DEVICE AND ENGINE HAVING THE SAME - Google Patents

Description

The present invention relates to a blow-by gas supply device that supplies blow-by gas to the intake ports of each cylinder, and an engine equipped with the blow-by gas supply device.

For example, diesel engines are equipped with a blow-by gas treatment device. The blow-by gas treatment device separates the blow-by gas generated inside the engine into oil components and gas components such as unburned gas. The gas components separated from the oil components are returned to the intake manifold of the engine's intake system and re-burned in each cylinder of the engine. This prevents the gas components separated from the oil components from being released outside the engine, improving the environmental performance of the engine.

However, it is difficult for the blow-by gas processing device to completely separate the blow-by gas into oil and gas components. Therefore, the gas components separated from the oil components contain a small amount of residual oil. Depending on the position and direction in which the gas components of the blow-by gas are returned to the intake manifold, the amount of residual oil adhering to the intake ports of multiple cylinders may be biased. For example, the amount of residual oil adhering to the intake port of a cylinder located relatively close to the position where the gas components of the blow-by gas are returned to the intake manifold is greater than the amount of residual oil adhering to the intake port of a cylinder located relatively far from the position where the gas components of the blow-by gas are returned to the intake manifold. In this case, the gas components of the blow-by gas and the new intake air may not be evenly drawn into the multiple cylinders. If the gas components of the blow-by gas and the new intake air are not evenly drawn into the multiple cylinders, there is a concern that the fuel efficiency of the engine may decrease and the generation of exhaust smoke may increase.

Patent Document 1 discloses a closed breather device for the crankcase of a multi-cylinder engine. In the engine disclosed in Patent Document 1, the blow-by gas guide passage has multiple branch outlet passages. The multiple branch outlet passages are connected to multiple locations in the longitudinal direction of the intake airflow chamber of the intake manifold at intervals. The blow-by gas is sucked into the intake airflow chamber in a dispersed manner from the multiple branch outlet passages. Therefore, the residual oil in the blow-by gas can be dispersed approximately uniformly among the multiple cylinders. This reduces the deterioration of the combustion performance of the multi-cylinder engine and reduces the amount of carbon deposition on the intake valves of each cylinder.

However, in the closed breather device described in Patent Document 1, the blow-by gas guide passage has multiple branch outlet passages, and the multiple branch outlet passages are connected to multiple locations along the length of the intake air flow chamber of the intake manifold at intervals. As a result, the piping system that supplies blow-by gas to the intake manifold tends to become larger, and there is room for improvement in terms of making the engine more compact.

Japanese Patent Application Laid-Open No. 7-83019

The present invention has been made to solve the above problems, and aims to provide a blow-by gas supply device and an engine equipped with a blow-by gas supply device that can prevent unevenness in the amount of residual oil adhering to the intake ports of multiple cylinders and can reduce the size of the engine.

The above problem is solved by the blow-by gas supply device according to the present invention, which is a blow-by gas supply device that supplies blow-by gas generated in an engine to the intake ports of multiple cylinders of the engine, and is characterized in that it comprises an intake manifold having an air intake port section that draws in intake air and supplies the intake air that has passed through the air intake port section to the intake ports of the multiple cylinders, and a blow-by gas supply pipe connected to the intake manifold and introduces the blow-by gas into the intake manifold, and the blow-by gas introduction direction that introduces the blow-by gas from the blow-by gas supply pipe into the inside of the intake manifold intersects with the intake air supply direction that supplies the intake air from the air intake port section to the inside of the intake manifold and has a component in the arrangement direction of the intake ports of the multiple cylinders.

In the blow-by gas supply device according to the present invention, the blow-by gas introduction direction for introducing the blow-by gas from the blow-by gas supply pipe into the inside of the intake manifold intersects with the intake air supply direction for supplying the intake air from the air intake port portion into the inside of the intake manifold. In addition, the blow-by gas introduction direction has a component in the arrangement direction of the intake ports of the multiple cylinders. As a result, the main gas component of the blow-by gas is guided in the arrangement direction of the intake ports of the multiple cylinders while mixing with the intake air. Therefore, the blow-by gas and the intake air are uniformly supplied to the intake ports of the multiple cylinders. Therefore, it is possible to avoid the main gas component of the blow-by gas being biasedly supplied to a specific cylinder, and to suppress the occurrence of bias in the amount of residual oil adhering to the intake ports of the multiple cylinders. In addition, since the blow-by gas and the intake air are uniformly supplied to the intake ports of the multiple cylinders, the mixture of air and fuel is good even in the intake port of a cylinder that is located relatively far from the position where the blow-by gas is returned to the intake manifold. This improves the engine's fuel efficiency and reduces the generation of exhaust smoke. In addition, the blow-by gas supply device according to the present invention has a simple structure in which the blow-by gas supply pipe is connected to the intake manifold, which allows the engine to be made smaller.

In the blow-by gas supply device according to the present invention, the blow-by gas introduction direction is preferably set from above the intake ports of the plurality of cylinders obliquely downward with respect to the arrangement direction.
In the blow-by gas supply device according to the present invention, the blow-by gas is introduced from above the intake ports of the cylinders diagonally downward with respect to the arrangement direction, so that even if the engine on which the blow-by gas supply device is mounted is tilted, the residual oil contained in the gas component of the blow-by gas can be prevented from flowing back from the intake manifold to the blow-by gas supply pipe, thereby preventing the residual oil from accumulating in the blow-by gas supply pipe.

In the blow-by gas supply device according to the present invention, the obliquely downward direction with respect to the arrangement direction is preferably at least 30 degrees and less than 80 degrees.
In the blow-by gas supply device according to the present invention, the angle at which the blow-by gas introduction direction is set diagonally downward with respect to the arrangement direction of the intake ports of the cylinders is 30 degrees or more and less than 80 degrees. Therefore, even if the engine on which the blow-by gas supply device is mounted is tilted by 30 degrees, it is possible to prevent the residual oil contained in the gas components of the blow-by gas from flowing back from the intake manifold to the blow-by gas supply pipe. This makes it possible to more reliably prevent the residual oil from accumulating in the blow-by gas supply pipe.

In the blow-by gas supply device according to the present invention, the obliquely downward direction is preferably at an angle of 45 degrees to the arrangement direction.
In the blow-by gas supply device according to the present invention, the angle at which the blow-by gas introduction direction is set diagonally downward with respect to the arrangement direction of the intake ports of the cylinders is 45 degrees. Therefore, even if the engine equipped with the blow-by gas supply device is tilted, the residual oil contained in the gas component of the blow-by gas can be more reliably prevented from flowing back from the intake manifold to the blow-by gas supply pipe. This makes it possible to more reliably prevent the residual oil from accumulating in the blow-by gas supply pipe.

In the blow-by gas supply device of the present invention, it is preferable that the intake manifold has an arc-shaped portion formed to match the shape of the air intake port, and the blow-by gas supply piping is connected tangentially to the arc-shaped portion.
In the blow-by gas supply device according to the present invention, the blow-by gas supply pipe is connected in a tangential direction to the arc-shaped portion of the intake manifold formed to match the shape of the air intake port. Therefore, when the main gas component of the blow-by gas is supplied to the inside of the intake manifold along the blow-by gas introduction direction, it is smoothly guided along the arc-shaped portion. Therefore, it is possible to suppress the main gas component of the blow-by gas from staying inside the intake manifold. As a result, the blow-by gas and the intake air are supplied more uniformly to the intake ports of the multiple cylinders. Therefore, it is possible to more reliably prevent the main gas component of the blow-by gas from being biasedly supplied to a specific cylinder, and more reliably suppress the bias in the amount of residual oil adhering to the intake ports of the multiple cylinders. In addition, since the blow-by gas and the intake air are supplied more uniformly to the intake ports of the multiple cylinders, the mixture of air and fuel is better even in the intake ports of the cylinders that are located relatively far from the position where the blow-by gas is returned to the intake manifold. This makes it possible to further improve the fuel efficiency of the engine and more reliably suppress the generation of exhaust smoke.

The above problem is solved by an engine according to the present invention, which is equipped with a blow-by gas supply device that supplies blow-by gas generated in the engine to the intake ports of multiple cylinders of the engine, the blow-by gas supply device having an air intake port section that draws in intake air and supplies the intake air that has passed through the air intake port section to the intake ports of the multiple cylinders, and a blow-by gas supply pipe connected to the intake manifold and introducing the blow-by gas into the intake manifold, the blow-by gas introduction direction that introduces the blow-by gas from the blow-by gas supply pipe into the inside of the intake manifold intersects with the intake air supply direction that supplies the intake air from the air intake port section to the inside of the intake manifold, and has a component in the arrangement direction of the intake ports of the multiple cylinders.

In an engine equipped with the blow-by gas supply device of the present invention, the blow-by gas introduction direction in which the blow-by gas is introduced from the blow-by gas supply pipe into the inside of the intake manifold intersects with the intake air supply direction in which the intake air is supplied from the air intake port portion into the inside of the intake manifold. In addition, the blow-by gas introduction direction has a component in the arrangement direction of the intake ports of the multiple cylinders. As a result, the main gas component of the blow-by gas is guided in the arrangement direction of the intake ports while mixing with the intake air. Therefore, the blow-by gas and the intake air are uniformly supplied to the intake ports of the multiple cylinders. Therefore, it is possible to avoid the main gas component of the blow-by gas being biasedly supplied to a specific cylinder, and to suppress the occurrence of bias in the amount of residual oil adhering to the intake ports of the multiple cylinders. In addition, since the blow-by gas and the intake air are uniformly supplied to the intake ports of the multiple cylinders, the mixture of air and fuel is good even in the intake port of a cylinder that is located relatively far from the position where the blow-by gas is returned to the intake manifold. This makes it possible to improve the fuel efficiency of the engine and suppress the generation of exhaust smoke. In addition, the blow-by gas supply device provided in the engine of the present invention has a simple structure in which the blow-by gas supply pipe is connected to the intake manifold, which allows the engine to be made smaller.

The present invention provides a blow-by gas supply device and an engine equipped with a blow-by gas supply device that can prevent unevenness in the amount of residual oil adhering to the intake ports of multiple cylinders and can reduce the size of the engine.

1 is a perspective view showing an engine equipped with a blow-by gas supply device according to an embodiment of the present invention. FIG. 1 is a side view showing an engine according to an embodiment of the present invention. 1 is a cross-sectional view showing an engine according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an engine equipped with a blow-by gas supply device according to a comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied to them, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is limited to them. In addition, in each drawing, similar components are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

(Engine 1 Overview)
FIG. 1 is a perspective view showing an engine equipped with a blow-by gas supply device according to an embodiment of the present invention.
FIG. 2 is a side view showing the engine according to this embodiment.

Engine 1 shown in Figures 1 and 2 is an internal combustion engine, for example an industrial diesel engine. In Figures 1 and 2, the X direction is the crankshaft direction, which is the front-to-rear direction of engine 1 shown in Figure 1. The Y direction is the left-to-right direction of engine 1, and is perpendicular to the crankshaft direction. The Z direction is the up-to-down direction of engine 1. The X, Y, and Z directions are perpendicular to each other.

Engine 1 is, for example, a multi-cylinder engine such as a naturally aspirated three-cylinder engine or a four-cylinder engine. In the example shown in FIG. 1, engine 1 is, for example, a naturally aspirated three-cylinder engine. Engine 1 is mounted on vehicles such as construction machinery, agricultural machinery, and lawn mowers.

(Structure example of engine 1)
1 and 2, the engine 1 includes a cylinder block 2, a cylinder head 3, a head cover 4, a blow-by gas supply device 30, and a blow-by gas processing device 100 (shown in FIG. 2). The cylinder head 3 is mounted on the cylinder block 2. The head cover 4 is mounted on the cylinder head 3.
Blow-by gas may be generated during at least one of the compression stroke and the combustion stroke of the engine 1 shown in Figures 1 and 2. The blow-by gas leaks from a gap between a cylinder and a piston (not shown) and rises into, for example, the head cover 4.

The blow-by gas processing device 100 is provided in the head cover 4. The blow-by gas processing device 100 separates the blow-by gas into an oil component and a gas component within the head cover 4. The blow-by gas processing device 100 has an outlet portion 110. The outlet portion 110 is provided on the upper surface portion 4T of the head cover 4, and is disposed at a rear position in the X direction, i.e., at a position on the rear side of the engine 1. The outlet portion 110 is provided with, for example, a pressure regulating valve (diaphragm) 120.

(Blow-by gas supply device 30)
Next, a preferred structural example of the blow-by gas supply device 30 according to this embodiment will be described with reference to FIGS.
The blow-by gas supply device 30 has a blow-by gas supply pipe 40 and an intake manifold 50. The blow-by gas supply device 30 separates the blow-by gas G generated in the engine 1 into an oil component and a gas component, and returns the gas component separated from the oil component to the intake ports of the multiple cylinders of the engine 1. The gas component of the blow-by gas G is then re-burned in the engine 1. This prevents the gas component separated from the oil component from being released to the outside of the engine 1, improving the environmental performance of the engine 1.

The blow-by gas supply pipe 40 is connected to the intake manifold 50, and introduces mainly the gas components of the blow-by gas G into the intake manifold 50 toward the intake ports of the multiple cylinders. The intake manifold 50 has an air intake port section 60 that draws in new intake air AR, and supplies the new intake air AR to the intake ports of the multiple cylinders. As a result, the intake manifold 50 mixes the gas components of the blow-by gas G introduced from the blow-by gas supply pipe 40 with the new intake air AR drawn in from the air intake port section 60, and supplies the resulting mixture to the intake ports of the multiple cylinders.

<Blow-by gas supply pipe 40>
Next, a preferred example of the structure of the blow-by gas supply pipe 40 will be described with reference to FIGS.
The blow-by gas supply pipe 40 is detachably connected between a cylindrical outlet connection pipe 41 having a circular cross section and a cylindrical inlet connection pipe 51 having a circular cross section. The outlet connection pipe 41 and the inlet connection pipe 51 are connected to each other via the blow-by gas supply pipe 40. The outlet connection pipe 41 is connected to the pressure regulating valve 120 of the outlet portion 110 described above, and is provided so as to protrude obliquely rearward at an inclination angle of, for example, 45 degrees within a plane formed by the X direction and the Y direction.

The inlet connection pipe 51 is provided near the air intake port 60 of the intake manifold 50 and is connected to the air intake port 60. The inlet connection pipe 51 is provided protruding from the air intake port 60 in a plane formed by the X direction and the Z direction while being tilted upward by a predetermined inclination angle θ. The blow-by gas supply pipe 40 is an elastically deformable cylindrical member with a circular cross section. The inlet side connection end 42 of the blow-by gas supply pipe 40 is fitted into the outlet connection pipe 41 and fixed with a mounting bracket 43. The outlet side connection end 44 of the blow-by gas supply pipe 40 is fitted into the inlet connection pipe 51 and fixed with a mounting bracket 45.

The main gas components of the blow-by gas G are supplied to the inside of the rear end 52 of the intake manifold 50 through the pressure regulating valve 120 of the blow-by gas processing device 100, the outlet connection pipe 41, the blow-by gas supply pipe 40, and the inlet connection pipe 51. The main gas components of the blow-by gas G supplied to the inside of the intake manifold 50 from the pressure regulating valve 120 through the blow-by gas supply pipe 40 are, for example, unburned gas components and burned gas components excluding oil components. It is difficult for the blow-by gas processing device 100 to completely separate the blow-by gas G into oil components and gas components. Therefore, a small amount of oil components may remain in the main gas components of the blow-by gas G. In this embodiment, for convenience of explanation, the oil components remaining in the gas components separated from the blow-by gas G are referred to as "residual oil". The oil components (lubricant components) separated from the blow-by gas G are collected in the engine 1, for example, through the head cover 4 and the cylinder head 3.

<Intake manifold 50>
Next, a preferred example of the structure of the intake manifold 50 will be described with reference to FIGS.
FIG. 3 is a cross-sectional view showing the engine according to this embodiment.
3, in order to show the insides of the intake manifold 50, the blow-by gas supply pipe 40, and the inlet connection pipe 51, the entire intake manifold 50, a portion of the blow-by gas supply pipe 40, and the inlet connection pipe 51 are shown in cross section. The intake manifold 50 is detachably fixed to the side surface of the cylinder head 3 using a plurality of bolts 53 and a gasket.

As shown in FIG. 3, the intake manifold 50 covers the intake ports 71, 72, and 73 of the multiple cylinders provided in the cylinder head 3. The intake port 71 is located at the front end 59 of the intake manifold 50 and corresponds to the first cylinder. Therefore, the main gas components of the new intake air AR and the blow-by gas G pass through the intake port 71 and are led to the first cylinder of the engine 1. The intake port 72 is located at the middle part 58 of the intake manifold 50 and corresponds to the second cylinder. Therefore, the main gas components of the new intake air AR and the blow-by gas G pass through the intake port 72 and are led to the second cylinder of the engine 1. The intake port 73 is located at the rear end 52 of the intake manifold 50 and corresponds to the third cylinder. Therefore, the main gas components of the new intake air AR and the blow-by gas G pass through the intake port 73 and are led to the third cylinder of the engine 1.

The air intake port 60 of the intake manifold 50 introduces new intake air AR into the intake manifold 50. The intake manifold 50 then sends the new intake air AR introduced into the intake manifold 50 through the air intake port 60 along the X1 direction parallel to the arrangement direction SD of the intake ports 73, 72, and 71 of the multiple cylinders, and supplies it uniformly to the multiple intake ports 73, 72, and 71.

As shown in Figures 1 to 3, the air intake port 60 is a cylindrical member with a circular cross section, and is formed at the rear end 52 of the intake manifold 50, protruding in the Y direction (the direction perpendicular to the paper surface of Figure 3). In other words, the intake air supply direction S when the air intake port 60 supplies new intake air AR into the intake manifold 50 is the Y direction, which is the direction perpendicular to the paper surface of Figure 3.

On the other hand, as shown in FIG. 3, mainly the gas components of the blow-by gas G are supplied into the intake manifold 50 through the outlet connection pipe 41, the blow-by gas supply pipe 40, and the inlet connection pipe 51. The blow-by gas introduction direction P, in which mainly the gas components of the blow-by gas G flow into the inside of the intake manifold 50, intersects with the intake air supply direction S. Specifically, the blow-by gas introduction direction P is perpendicular to the intake air supply direction S. In addition, the blow-by gas introduction direction P has a component in the arrangement direction SD of the intake ports 73, 72, and 71 of the multiple cylinders. In the example shown in FIG. 3, the blow-by gas introduction direction P has a rightward component in the arrangement direction SD.

3, the blow-by gas introduction direction P is set obliquely downward from above the multiple intake ports 73, 72, 71 with respect to the arrangement direction SD of the multiple intake ports 73, 72, 71. That is, the blow-by gas introduction direction P is set to be inclined obliquely downward from above by a predetermined inclination angle θ in a plane formed by the X direction and the Z direction with respect to the arrangement direction SD of the multiple intake ports 73, 72, 71. As a result, the main gas component of the blow-by gas G is supplied into the rear end portion 52 of the intake manifold 50 at an inclination angle θ. Therefore, a component of the arrangement direction SD of the multiple intake ports 73, 72, 71 is generated as a component in the direction in which the main gas component of the blow-by gas G is sent. Therefore, the main gas component of the blow-by gas G is uniformly supplied to the multiple intake ports 73, 72, 71.

The inclination angle θ is set as the relationship between the blow-by gas introduction direction P through the blow-by gas supply pipe 40 and the arrangement direction SD of the intake ports 73, 72, and 71 of the multiple cylinders. The inclination angle θ is preferably set in the range of 30 degrees or more and less than 80 degrees. The inclination angle θ is more preferably set to 45 degrees.

As shown in FIG. 3, the intake manifold 50 has an arc-shaped portion 55 formed to match the cylindrical shape of the air intake port 60. The arc-shaped portion 55 is formed inside the intake manifold 50 at a location corresponding to the bottom of the air intake port 60.

The blow-by gas supply pipe 40 is connected tangentially to the arc-shaped portion 55 of the intake manifold 50. Therefore, the blow-by gas introduction direction P by the blow-by gas supply pipe 40 is parallel to the tangential direction of the arc-shaped portion 55. Mainly the gas components of the blow-by gas G flow into the inside of the rear end portion 52 of the intake manifold 50 along the blow-by gas introduction direction P, and also along the tangential direction of the arc-shaped portion 55, at an angle from above to below.

Comparative Example
Now, an engine equipped with a blow-by gas supply device according to a comparative example will be described with reference to FIG.
FIG. 4 is a cross-sectional view showing an engine equipped with a blow-by gas supply device according to a comparative example.

In an engine equipped with a blow-by gas supply device according to the comparative example shown in FIG. 4, the blow-by gas supply pipe 200 is connected to the end of the intake manifold 150, i.e., near the intake port 173 corresponding to the third cylinder. The supply direction N of the blow-by gas supplied from the blow-by gas supply pipe 200 is perpendicular to the arrangement direction H of the multiple intake ports 173, 172, and 171. Therefore, the supply of blow-by gas is concentrated at the intake port 173 of a specific cylinder.

Therefore, the amount of residual oil contained in the gas components of the blow-by gas is the largest in the intake port 173 compared to the intake ports 171 and 172. In this way, in an engine equipped with a blow-by gas supply device according to the comparative example, the amount of residual oil adhering to the intake ports 173, 172, and 171 of the multiple cylinders in the intake manifold 150 is biased. If the amount of residual oil adhering is biased, the gas components of the blow-by gas and the new intake air may not be evenly sucked into the multiple cylinders. In the comparative example shown in FIG. 4, the gas components of the blow-by gas and the new intake air sucked into the cylinder corresponding to the intake port 173, which has a larger amount of residual oil adhering than the intake ports 171 and 172, are greater than the gas components of the blow-by gas and the new intake air sucked into the cylinders corresponding to the intake ports 171 and 172. Therefore, the fuel efficiency of the engine may decrease and the generation of exhaust smoke may increase.

In contrast, in the blow-by gas supply device 30 according to this embodiment, as described above with reference to FIGS. 1 to 3, the blow-by gas introduction direction P, which introduces the blow-by gas G from the blow-by gas supply pipe 40 into the inside of the intake manifold 50, intersects with the intake air supply direction S, which supplies the intake air AR from the air intake port 60 into the inside of the intake manifold 50. In addition, the blow-by gas introduction direction P has a component in the arrangement direction SD of the intake ports 73, 72, and 71 of the multiple cylinders. As a result, the main gas components of the blow-by gas G are guided to the arrangement direction SD of the intake ports 73, 72, and 71 of the multiple cylinders while mixing with the intake air AR. Therefore, the blow-by gas G and the intake air AR are uniformly supplied to the intake ports 71, 72, and 73 of the multiple cylinders. Therefore, it is possible to avoid the main gas components of the blow-by gas G being biasedly supplied to a specific cylinder, and to suppress the occurrence of bias in the amount of residual oil adhering to the intake ports 71, 72, and 73 of the multiple cylinders. In addition, since the blow-by gas G and the intake air AR are uniformly supplied to the intake ports 71, 72, and 73 of the cylinders, the mixture of air and fuel is good even in the intake ports 71 and 72 of the cylinders that are located relatively far from the position where the blow-by gas G is returned to the intake manifold 50 (in this embodiment, the position where the inlet connection pipe 51 is connected to the air intake port portion 60). This improves the fuel efficiency of the engine 1 and suppresses the generation of exhaust smoke. In addition, the blow-by gas supply device 30 according to this embodiment has a simple structure in which the blow-by gas supply pipe 40 is connected to the intake manifold 50, so that the engine 1 can be made smaller.

In addition, because the blow-by gas introduction direction P is set from above the intake ports 71, 72, 73 of the multiple cylinders diagonally downward with respect to the arrangement direction, even if the engine 1 equipped with the blow-by gas supply device 30 is tilted, the residual oil contained in the gas components of the blow-by gas G can be prevented from flowing back from the intake manifold 50 toward the blow-by gas supply pipe 40. This makes it possible to prevent the residual oil from accumulating in the blow-by gas supply pipe 40.

The inclination angle θ of the blow-by gas introduction direction P, which is set diagonally downward with respect to the arrangement direction SD of the intake ports 73, 72, 71 of the multiple cylinders, is greater than or equal to 30 degrees and less than 80 degrees. Therefore, even if the engine 1 equipped with the blow-by gas supply device 30 is tilted by 30 degrees, the residual oil contained in the gas components of the blow-by gas G can be prevented from flowing back from the intake manifold 50 toward the blow-by gas supply pipe 40. This makes it possible to more reliably prevent the residual oil from accumulating in the blow-by gas supply pipe 40.

The inclination angle θ at which the blow-by gas introduction direction P is set diagonally downward with respect to the arrangement direction SD of the intake ports 73, 72, 71 of the multiple cylinders is preferably 45 degrees. Therefore, even if the engine 1 equipped with the blow-by gas supply device 30 is tilted, the residual oil contained in the gas components of the blow-by gas G can be more reliably prevented from flowing back from the intake manifold 50 toward the blow-by gas supply pipe 40. This makes it possible to more reliably prevent the residual oil from accumulating in the blow-by gas supply pipe 40.

In addition, in the blow-by gas supply device 30 according to this embodiment, the blow-by gas supply pipe 40 is connected tangentially to the arc-shaped portion 55 of the intake manifold 50, which is formed to match the shape of the air intake port portion 60. Therefore, when the main gas components of the blow-by gas G are supplied to the inside of the intake manifold 50 along the blow-by gas introduction direction P, they are smoothly guided along the arc-shaped portion 55. Therefore, it is possible to suppress the main gas components of the blow-by gas G from stagnation inside the intake manifold 50. As a result, the blow-by gas G and the intake air AR are supplied more uniformly to the intake ports 71, 72, and 73 of the multiple cylinders. Therefore, it is possible to more reliably prevent the main gas components of the blow-by gas G from being biasedly supplied to a specific cylinder, and more reliably suppress the bias in the amount of residual oil adhering to the intake ports 71, 72, and 73 of the multiple cylinders. In addition, because the blow-by gas G and intake air AR are supplied more uniformly to the intake ports 71, 72, and 73 of the multiple cylinders, the air and fuel are mixed better even in the intake ports 71 and 72 of the cylinders that are located relatively far from the position where the blow-by gas G is returned to the intake manifold 50. This makes it possible to further improve the fuel efficiency of the engine 1 and more reliably suppress the generation of exhaust smoke.

The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or arbitrarily combined in a manner different from the above.
For example, the engine 1 is not limited to a naturally aspirated multi-cylinder diesel engine, but may be a turbocharged, high-output, supercharged multi-cylinder diesel engine. Furthermore, the engine 1 is not limited to a diesel engine, but may be a naturally aspirated multi-cylinder gasoline engine or a turbocharged, supercharged multi-cylinder gasoline engine. The engine 1 can also be installed in vehicles other than those such as construction machines, agricultural machines, and lawnmowers, and may be a small or large displacement engine.

1: engine, 2: cylinder block, 3: cylinder head, 4: head cover, 4T: upper surface portion, 30: blow-by gas supply device, 40: blow-by gas supply pipe, 41: outlet connection pipe, 42: inlet connection end portion, 43: mounting bracket, 44: outlet connection end portion, 45: mounting bracket, 50: intake manifold, 51: inlet connection pipe, 52: rear end portion, 53: bolt, 55: arc-shaped portion, 58: middle portion, 59: front end portion, 60: air intake port portion, 71, 72, 73: intake port, 100: blow-by gas processing device, 110: outlet portion, 120: pressure regulating valve, 150: intake manifold, 171, 172, 173: intake port, 200: blow-by gas supply pipe, AR: intake air, G: blow-by gas, H: arrangement direction, N: supply direction, P: blow-by gas introduction direction, S: intake air supply direction, SD: arrangement direction

Claims (7)

A blow-by gas supply device that supplies blow-by gas generated in an engine to intake ports of a plurality of cylinders of the engine,
an intake manifold having an air intake port portion for taking in intake air, the intake manifold supplying the intake air that has passed through the air intake port portion to the intake ports of the plurality of cylinders;
a blow-by gas supply pipe connected to the intake manifold and configured to introduce the blow-by gas into the intake manifold;
Equipped with
the air intake portion is disposed on one end side of all of the intake ports of the plurality of cylinders in an arrangement direction of the intake ports of the plurality of cylinders,
a blow-by gas introduction direction for introducing the blow-by gas from the blow-by gas supply pipe into the inside of the intake manifold intersects with an intake air supply direction for supplying the intake air from the air intake port portion to the inside of the intake manifold, has a component in the arrangement direction, and is set from above the intake ports of the plurality of cylinders obliquely downward with respect to the arrangement direction ,
A blow-by gas supply device characterized in that the direction of the blow-by gas introduction direction has a component of the arrangement direction that is the same as the direction from the one end to the other end in the arrangement direction within the interior of the intake manifold. 2. The blow-by gas supply device according to claim 1 , wherein the obliquely downward direction with respect to the arrangement direction is at least 30 degrees and less than 80 degrees. 3. The blow-by gas supply device according to claim 2 , wherein the obliquely downward direction is at an angle of 45 degrees with respect to the arrangement direction. the intake manifold has an arc-shaped portion formed to match the shape of the air intake port,
4. The blow-by gas supply device according to claim 1, wherein the blow-by gas supply pipe is connected in a tangential direction to the arc-shaped portion. A blow-by gas supply device that supplies blow-by gas generated in an engine to intake ports of a plurality of cylinders of the engine,
an intake manifold having an air intake port portion for taking in intake air and an arc-shaped portion formed to match the shape of the air intake port portion , the intake manifold supplying the intake air that has passed through the air intake port portion to the intake ports of the plurality of cylinders;
a blow-by gas supply pipe connected in a tangential direction to the arc-shaped portion of the intake manifold and configured to introduce the blow-by gas into the intake manifold;
Equipped with
the air intake portion is disposed on one end side of all of the intake ports of the plurality of cylinders in an arrangement direction of the intake ports of the plurality of cylinders,
a blow-by gas introduction direction in which the blow-by gas is introduced from the blow-by gas supply pipe into the inside of the intake manifold intersects with an intake air supply direction in which the intake air is supplied from the air intake port portion to the inside of the intake manifold and has a component in the arrangement direction,
A blow-by gas supply device characterized in that the direction of the blow-by gas introduction direction has a component of the arrangement direction that is the same as the direction from the one end to the other end in the arrangement direction within the interior of the intake manifold. An engine including a blow-by gas supply device that supplies blow-by gas generated in the engine to intake ports of a plurality of cylinders of the engine,
The blow-by gas supply device is
an intake manifold having an air intake port portion for taking in intake air, the intake manifold supplying the intake air that has passed through the air intake port portion to the intake ports of the plurality of cylinders;
a blow-by gas supply pipe connected to the intake manifold and configured to introduce the blow-by gas into the intake manifold;
having
the air intake portion is disposed on one end side of all of the intake ports of the plurality of cylinders in an arrangement direction of the intake ports of the plurality of cylinders,
a blow-by gas introduction direction for introducing the blow-by gas from the blow-by gas supply pipe into the inside of the intake manifold intersects with an intake air supply direction for supplying the intake air from the air intake port portion to the inside of the intake manifold, has a component in the arrangement direction, and is set from above the intake ports of the plurality of cylinders obliquely downward with respect to the arrangement direction ,
An engine characterized in that the direction of the blow-by gas introduction direction has a component of the arrangement direction, which is the same as the direction from the one end to the other end in the arrangement direction within the interior of the intake manifold. An engine including a blow-by gas supply device that supplies blow-by gas generated in the engine to intake ports of a plurality of cylinders of the engine,
The blow-by gas supply device is
an intake manifold having an air intake port portion for taking in intake air and an arc-shaped portion formed to match the shape of the air intake port portion , the intake manifold supplying the intake air that has passed through the air intake port portion to the intake ports of the plurality of cylinders;
a blow-by gas supply pipe connected in a tangential direction to the arc-shaped portion of the intake manifold and configured to introduce the blow-by gas into the intake manifold;
having
the air intake portion is disposed on one end side of all of the intake ports of the plurality of cylinders in an arrangement direction of the intake ports of the plurality of cylinders,
a blow-by gas introduction direction in which the blow-by gas is introduced from the blow-by gas supply pipe into the inside of the intake manifold intersects with an intake air supply direction in which the intake air is supplied from the air intake port portion to the inside of the intake manifold and has a component in the arrangement direction,
An engine characterized in that the direction of the blow-by gas introduction direction has a component of the arrangement direction, which is the same as the direction from the one end to the other end in the arrangement direction within the interior of the intake manifold.

Images