Blow-by gas recirculation device for internal combustion engines

Abstract

To provide an internal combustion engine blow-by gas recirculation device in which the detection accuracy of blow-by gas pressure is prevented from degrading.SOLUTION: A blow-by gas recirculation device for an internal combustion engine mounted with a supercharger comprises: an oil separator which has a first communication port communicated with a head cover of the internal combustion engine, a second communication port communicated with an intake passage at an upstream side of a compressor of the supercharger and a third communication port; a case which compartmentalizes an auxiliary chamber communicated with the third communication port; and a pressure sensor which detects pressure inside the auxiliary chamber. A straight-line distance between the second communication port and the third communication port is longer than a straight-line distance between the first communication port and the second communication port and also longer than a straight-line distance between the first communication port and the third communication port.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a blow-by gas recirculation device for an internal combustion engine. [Background technology]

[0002] By communicating the atmosphere-side separator with the pressure sensor via the sub-chamber, the influence of the flow of blow-by gas can be suppressed and the pressure of the blow-by gas can be detected (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-113521 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the flow rate of blow-by gas is large relative to the volume of the auxiliary chamber, the flow of blow-by gas may reduce the accuracy of pressure detection by the pressure sensor.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a blow-by gas recirculation device for an internal combustion engine in which a decrease in the detection accuracy of the blow-by gas pressure is suppressed. [Means for solving the problem]

[0006] The object is to provide a blow-by gas recirculation device for an internal combustion engine equipped with a turbocharger, the device comprising: an oil separator having a first communication port communicating with a head cover of the internal combustion engine, a second communication port communicating with an intake passage upstream of a compressor of the turbocharger, and a third communication port; a case defining an auxiliary chamber communicating with the third communication port; and a pressure sensor for detecting pressure in the auxiliary chamber, wherein a linear distance between the second communication port and the third communication port is longer than a linear distance between the first communication port and the second communication port, and is also longer than a linear distance between the first communication port and the third communication port. the second communication port is located on one side of the first communication port in the longitudinal direction of the oil separator, and the third communication port is located on the other side of the first communication port in the longitudinal direction of the oil separator, the linear distance between the first communication port and the second communication port is longer than the linear distance between the first communication port and the third communication port, a first communication pipe communicating the third communication port with the auxiliary chamber, and a second communication pipe communicating the case with the pressure sensor, the internal combustion engine is a four-cylinder engine, and the oil separator is shaped like a substantially rectangular parallelepiped. the longitudinal direction of the oil separator is substantially parallel to a crankshaft of the internal combustion engine, the second communication port is spaced apart from the first communication port in the longitudinal direction, the third communication port is spaced apart from the first communication port in the longitudinal direction, a diameter of the third communication port is smaller than a diameter of the first communication port and smaller than a diameter of the second communication port, the second communication port is spaced apart from the first communication port in a direction perpendicular to the longitudinal direction, and the third communication port is spaced apart from the first communication port in the direction perpendicular to the longitudinal direction. This can be achieved by a blow-by gas recirculation system for an internal combustion engine. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a blow-by gas recirculation device for an internal combustion engine in which a decrease in the detection accuracy of the blow-by gas pressure is suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of the engine. [Figure 2] 2A and 2B are schematic diagrams of the atmosphere-side separator. [Figure 3] 3A and 3B are schematic diagrams showing the flow of blow-by gas in the atmosphere-side separator during supercharging operation. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Engine outline] 1 is a schematic diagram of an engine 10. The engine 10 is a spark-ignition four-cylinder gasoline engine and is an example of an internal combustion engine, but is not limited to this and may be an engine other than four cylinders, for example, a compression-ignition diesel engine or other type of engine.

[0013] The engine 10 includes an engine body 11, a head cover 12, a crankcase 13, a piston 14, a combustion chamber 15, an intake passage 16, a turbocharger 20, an intercooler 22, and a throttle valve 24. The engine body 11 has a cylinder 11a, a head cover 12 provided above the cylinder 11a, and a crankcase 13 provided below the cylinder 11a. The piston 14 reciprocates within the combustion chamber 15 of the cylinder 11a. An intake passage 16 is connected to each cylinder of the engine body 11 via an intake manifold 16a.

[0014] The air cleaner 17 is attached near the inlet of the intake passage 16. The compressor 20a of the turbocharger 20 is installed downstream of the air cleaner 17 in the intake passage 16 and compresses the intake air. The compressor 20a is integrally connected via a connecting shaft to a turbine 20b arranged in the exhaust passage.

[0015] The intercooler 22 is installed downstream of the compressor 20a in the intake passage 16 and cools the supercharged air. An electronically controlled throttle valve 24 is provided downstream of the intercooler 22. The intake manifold 16a is disposed downstream of the throttle valve 24.

[0016] A blow-by gas guide passage 31 is provided inside the cylinder 11a and the head cover 12. This blow-by gas guide passage 31 is formed by penetrating the inside of the cylinder 11a and the head cover 12, and connects the inside of the crankcase 13 to the main separator 43, guiding blow-by gas present in the crankcase 13 to the main separator 43. In addition, a communication port 431 is provided in the main separator 43, which connects the head cover 12 to the main separator 43, and guides blow-by gas present in the internal space of the head cover 12 to the main separator 43.

[0017] The blow-by gas is guided to the main separator 43 via the blow-by gas guide passage 31, and the blow-by gas from which the oil mist has been separated in the main separator 43 is returned to the intake manifold 16a via the blow-by gas return passage 36 that connects the main separator 43 to the intake manifold 16a.

[0018] A PCV (Positive Crankcase Ventilation) valve 38 is installed at the end of the blow-by gas recirculation passage 36 on the main separator 43 side. The PCV valve 38 is configured as a differential pressure actuated valve that operates in response to the differential pressure between the internal space of the head cover 12 on the upstream side and the intake manifold 16a on the downstream side. The PCV valve 38 adjusts the flow rate of the blow-by gas recirculating to the intake manifold 16a and prevents the blow-by gas from flowing back into the internal space of the head cover 12.

[0019] A fresh air introduction passage 34 is provided that connects the internal space of the head cover 12 to the intake passage 16 upstream of the compressor 20a and downstream of the air cleaner 17. More specifically, the fresh air introduction passage 34 connects the intake passage 16 to an atmosphere-side separator 44 included in the blow-by gas recirculation device 4, which will be described later. A first communication port 441 is provided in the atmosphere-side separator 44, connecting the atmosphere-side separator 44 to the internal space of the head cover 12. Furthermore, a fresh air guide passage 33 connects the interior of the head cover 12 to the interior of the crankcase 13. Thus, fresh air passing through the intake passage 16 is introduced into the internal space of the head cover 12 and the crankcase 13 by the fresh air introduction passage 34, the atmosphere-side separator 44, and the fresh air guide passage 33.

[0020] When the engine 10 is operated in a naturally aspirated state, the combustion chamber 15 and the intake manifold 16a, which are downstream of the throttle valve 24, are under negative pressure, while the intake passage 16, which is upstream of the compressor 20a, is under atmospheric pressure. As a result, fresh air flows through the fresh air introduction passage 34, the atmosphere-side separator 44, the head cover 12, the fresh air guide passage 33, and the crankcase 13. Blow-by gas is returned from the crankcase 13 and the head cover 12 to the intake manifold 16a via the main separator 43 and the blow-by gas return passage 36. The main separator 43 separates oil components from the blow-by gas. In this way, the blow-by gas is supplied from the intake manifold 16a into the combustion chamber 15, where it can be burned.

[0021] When the engine 10 is operated in a supercharged state, the combustion chamber 15 and the intake manifold 16a downstream of the compressor 20a are under positive pressure, while the intake passage 16 upstream of the compressor 20a is under negative pressure. As a result, blow-by gas flows from the crankcase 13 through the blow-by gas guide passage 31, the main separator 43, the head cover 12, the atmosphere-side separator 44, and the fresh air introduction passage 34 in this order, before flowing back into the intake passage 16 upstream of the compressor 20a. In the atmosphere-side separator 44, oil components are separated from the blow-by gas. In this way, the blow-by gas is supplied into the combustion chamber 15, where it can be burned.

[0022] [Outline of the blow-by gas recirculation device] The blow-by gas recirculation device 4 has an atmosphere-side separator 44, a first communicating pipe 51, a second communicating pipe 52, a case 60, and a pressure sensor 70. The atmosphere-side separator 44 is an example of an oil separator. The atmosphere-side separator 44 includes a first communicating port 441, a second communicating port 442, and a third communicating port 443. The first communicating port 441 communicates with the interior of the head cover 12. The second communicating port 442 communicates with the fresh air introduction passage 34. The third communicating port 443 communicates with the pressure sensor 70 via the first communicating pipe 51, the case 60, and the second communicating pipe 52. The case 60 defines an auxiliary chamber 61. Although the case 60 is shown schematically in FIG. 1 , it is actually fixed to the upper surface of the head cover 12.

[0023] The pressure sensor 70 is not directly attached to the atmosphere-side separator 44, but is attached via the auxiliary chamber 61 that communicates with the atmosphere-side separator 44. In detail, the auxiliary chamber 61 of the case 60 communicates with the atmosphere-side separator 44 via the first communicating pipe 51, and the pressure sensor 70 communicates with the auxiliary chamber 61 of the case 60 via the second communicating pipe 52. Therefore, the pressure sensor 70 is provided at a position where it is less susceptible to the effect of the flow of blow-by gas within the atmosphere-side separator 44, and a decrease in the detection accuracy of the pressure sensor 70 due to the effect of the flow of blow-by gas is suppressed.

[0024] [Outline of the atmosphere-side separator] The configuration of the atmosphere-side separator 44 will be described. Figures 2A and 2B are schematic diagrams of the atmosphere-side separator 44. Figure 2A is a schematic diagram of the atmosphere-side separator 44 as seen from the side of the engine 10. Figure 2B is a schematic diagram of the atmosphere-side separator 44 as seen from above the engine 10. In Figures 2A and 2B, the horizontal direction of the paper is the longitudinal direction of the atmosphere-side separator 44. The atmosphere-side separator 44 is formed in a substantially rectangular parallelepiped shape. The atmosphere-side separator 44 is attached to the head cover 12 so that the longitudinal direction of the atmosphere-side separator 44 is substantially parallel to the crankshaft of the engine 10.

[0025] 2A and 2B show linear distances L12, L13, and L23. The linear distance L12 indicates the linear distance between the center of the first communication port 441 and the center of the second communication port 442. The linear distance L13 indicates the linear distance between the center of the first communication port 441 and the center of the third communication port 443. The linear distance L23 indicates the linear distance between the center of the second communication port 442 and the center of the third communication port 443. The positions of the first communication port 441, the second communication port 442, and the third communication port 443 are set so that the linear distance L23 is the longest of the linear distances L12, L13, and L23.

[0026] 3A and 3B are schematic diagrams showing the flow of blow-by gas in the atmosphere-side separator 44 during turbocharging operation. FIGS. 3A and 3B correspond to FIGS. 2A and 2B, respectively. Since the linear distance between the second communication port 442 and the third communication port 443 is long, the third communication port 443 is separated from the region through which blow-by gas flows from the first communication port 441 to the second communication port 442. Therefore, even if the flow rate of blow-by gas from the first communication port 441 to the second communication port 442 is greater than the volume of the auxiliary combustion chamber 61, the flow of blow-by gas into the third communication port is suppressed. This prevents a decrease in the detection accuracy of the pressure sensor 70 due to the flow of blow-by gas.

[0027] Furthermore, the second communication port 442 is located on one side in the longitudinal direction of the atmosphere-side separator 44 (the left side in FIG. 2A ) of the first communication port 441. In contrast, the third communication port 443 is located on the other side in the longitudinal direction of the atmosphere-side separator 44 (the right side in FIG. 2A ) of the first communication port 441. This configuration also prevents blow-by gas flowing from the first communication port 441 to the second communication port 442 from flowing to the third communication port 443, thereby preventing a decrease in the detection accuracy of the pressure sensor 70.

[0028] The linear distance L12 between the first communication port 441 and the second communication port 442 is longer than the linear distance L13 between the first communication port 441 and the third communication port 443. This ensures enough time for the blow-by gas to flow in from the first communication port 441 and flow out from the second communication port 442, allowing the oil component to be sufficiently separated from the blow-by gas.

[0029] In the above embodiment, the case 60 is formed separately from the atmosphere-side separator 44, but this is not limited to this. The case 60 may be formed integrally with the atmosphere-side separator 44, or may be provided integrally with another component.

[0030] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0031] 10 Engine 16 Intake passage 20. Turbocharger 20a compressor 44 Atmospheric side separator (oil separator) 441 1st communication port 442 2nd communication port 443 3rd communication port 51 1st communication pipe 52 2nd communication pipe 60 cases 61 Antechamber 70 Pressure Sensor

Claims

[Claim 1] In a blow-by gas recirculation device for an internal combustion engine equipped with a turbocharger, an oil separator having a first communication port communicating with a head cover of the internal combustion engine, a second communication port communicating with an intake passage upstream of a compressor of the turbocharger, and a third communication port; a case defining an auxiliary chamber communicating with the third communication port; a pressure sensor for detecting the pressure in the sub-chamber; Equipped with a linear distance between the second communication port and the third communication port is longer than a linear distance between the first communication port and the second communication port, and is also longer than a linear distance between the first communication port and the third communication port; the second communication port is located on one side of the first communication port in the longitudinal direction of the oil separator, the third communication port is located on the other side of the first communication port in the longitudinal direction of the oil separator, a linear distance between the first communication port and the second communication port is longer than a linear distance between the first communication port and the third communication port; a first communication pipe that communicates the third communication port with the sub-chamber; a second communication pipe that communicates between the case and the pressure sensor, the internal combustion engine is a four-cylinder engine, The oil separator is formed in a substantially rectangular parallelepiped shape, the longitudinal direction of the oil separator is substantially parallel to a crankshaft of the internal combustion engine, the second communication port is spaced apart from the first communication port in the longitudinal direction, the third communication port is spaced apart from the first communication port in the longitudinal direction, a diameter of the third communication port is smaller than a diameter of the first communication port and smaller than a diameter of the second communication port; the second communication port is spaced apart from the first communication port in a direction perpendicular to the longitudinal direction, a third communication port spaced apart from the first communication port in the direction perpendicular to the longitudinal direction;

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