Blow-by gas recirculation device

Abstract

To detect leakage of blow-by gas by using a simple configuration.SOLUTION: A blow-by gas recirculation device includes: an engine having a rocker chamber formed between a cylinder head and a rocker cover, a crank chamber formed by a crank case, and a communication hole through which the rocker chamber and the crank chamber communicate; a turbocharger having a turbine housing, a compressor housing, and a center housing disposed between the turbine housing and the compressor housing; and a blow-by gas communication passage that is formed on wall parts of the cylinder head, the turbine housing, the center housing, and the compressor housing as a through hole and connects the rocker chamber and an upstream side of a compressor impeller of an intake flow passage in the compressor housing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a blow-by gas recirculation device. [Background technology]

[0002] Conventionally, in an engine, blow-by gas, which contains combustion gas and unburned mixture gas that have become high pressure during the combustion stroke, leaks out from the gap between the cylinder and the piston and accumulates in the crankcase. For this reason, a blow-by gas recirculation device is provided in the engine system to recirculate the blow-by gas to the intake passage. The blow-by gas recirculation device returns the blow-by gas in the crankcase to the intake passage and introduces it into the combustion chamber of the engine again.

[0003] Patent Document 1 discloses a blow-by gas recirculation device for a vehicle equipped with a turbocharger. The blow-by gas recirculation device of Patent Document 1 is provided with a blow-by gas pipe that connects the cylinder rocker cover of the engine and the diffuser passage of the compressor housing to prevent the adhesion of deposits in the diffuser passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-27251 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, North American regulations require that not only the leakage of blow-by gas caused by the disconnection of the blow-by gas piping, but also the leakage caused by the breakage of the blow-by gas piping be detectable. In order to satisfy such North American regulations, the blow-by gas recirculation device as disclosed in Patent Document 1 required additional hardware configurations such as a crankcase internal pressure sensor and an ON-OFF valve to enable the detection of the leakage caused by the breakage of the blow-by gas piping. This resulted in a problem of the configuration of the blow-by gas recirculation device becoming complicated.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a blow-by gas recirculation device capable of detecting the leakage of blow-by gas with a simple configuration. [Means for solving the problem]

[0007] In order to solve the above problems, the blow-by gas recirculation device of the present invention comprises: an engine having a rocker chamber formed between a cylinder head and a rocker cover, a crank chamber formed by a crankcase, and a communication hole communicating the rocker chamber and the crank chamber; a turbocharger having a turbine housing, a compressor housing, and a center housing disposed between the turbine housing and the compressor housing; a blow-by gas communication passage formed as a through hole in a wall portion of the cylinder head, the turbine housing, the center housing, and the compressor housing, and connecting the locker chamber with an upstream side of a compressor impeller of an intake flow passage in the compressor housing; Equipped with: Effect of the Invention

[0008] According to the present invention, it is possible to detect the leakage of blow-by gas with a simple configuration. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a schematic diagram showing a configuration of an engine system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the blow-by gas recirculation device according to the first embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a blow-by gas recirculation device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0011] Fig. 1 is a schematic diagram showing a configuration of an engine system 1 according to a first embodiment. The engine system 1 according to the first embodiment is provided in a vehicle 10. As shown in Fig. 1, the engine system 1 includes an engine 100, an intake system 200, an exhaust system 300, and a blow-by gas recirculation device 400.

[0012] The engine 100 includes a cylinder block 102, a crankcase 104, a cylinder head 106, a rocker cover 108, and an oil pan 110. The crankcase 104 is formed integrally with the cylinder block 102. The cylinder head 106 is connected to an upper part of the cylinder block 102. The rocker cover 108 is connected to an upper part of the cylinder head 106. The cylinder head 106 is disposed between the cylinder block 102 and the rocker cover 108. The oil pan 110 is connected to a bottom part of the crankcase 104.

[0013] A plurality of cylinder bores 112 are formed in the cylinder block 102. A piston 114 is slidably supported in each of the cylinder bores 112 by a connecting rod 116. In the engine 100, a space surrounded by the cylinder bores 112, the cylinder head 106, and the crown surface of the piston 114 is formed as a combustion chamber 118.

[0014] In the engine 100, a space formed between the crankcase 104 and the oil pan 110 serves as a crank chamber 120. A crankshaft 122 is rotatably supported within the crank chamber 120. The piston 114 is connected to the crankshaft 122 via a connecting rod 116.

[0015] An intake port 124 and an exhaust port 126 are provided in the cylinder head 106 so as to communicate with the combustion chamber 118. The tip of an intake valve 128 is located between the intake port 124 and the combustion chamber 118, and the tip of an exhaust valve 130 is located between the exhaust port 126 and the combustion chamber 118.

[0016] In the engine 100, a space formed between the cylinder head 106 and the rocker cover 108 serves as a rocker chamber 132. An intake camshaft 134 and an exhaust camshaft 136 are rotatably supported in the rocker chamber 132.

[0017] A plurality of intake valve cams 134a are fixed to the intake camshaft 134. The intake valve cams 134a are in contact with the ends of the intake valves 128, and rotate with the rotation of the intake camshaft 134, thereby moving the intake valves 128 in the axial direction. As a result, the intake valves 128 open and close the space between the intake port 124 and the combustion chamber 118.

[0018] A plurality of exhaust valve cams 136a are fixed to the exhaust camshaft 136. The exhaust valve cams 136a are in contact with the ends of the exhaust valves 130, and rotate with the rotation of the exhaust camshaft 136, thereby moving the exhaust valves 130 in the axial direction. As a result, the exhaust valves 130 open and close the gap between the exhaust port 126 and the combustion chamber 118.

[0019] In addition, an injector and a spark plug (not shown) are provided in the cylinder head 106. Fuel injected from the injector into the combustion chamber 118 is mixed with air supplied to the combustion chamber 118 via an intake port 124 to generate an air-fuel mixture. The spark plug is then ignited at a predetermined timing, and the air-fuel mixture generated in the combustion chamber 118 is burned. This combustion causes the piston 114 to perform a reciprocating motion, and this reciprocating motion is converted into the rotational motion of the crankshaft 122 via the connecting rod 116.

[0020] The intake system 200 includes an intake pipe 202, an air cleaner 204, an intercooler 206, a throttle valve 208, and an intake manifold 210. The intake manifold 210 is connected to the upstream side of the intake port 124. An intake passage 220 is formed inside the intake pipe 202. The intake passage 220 communicates with the intake port 124. The engine system 1 of the first embodiment is also provided with a turbocharger TC. The turbocharger TC includes a compressor C and a turbine T.

[0021] An air cleaner 204, a compressor C, an intercooler 206, a throttle valve 208, and an intake manifold 210 are provided in the intake pipe 202 in this order from the upstream side to the downstream side. The intake air purified by the air cleaner 204 is introduced into the combustion chamber 118 through an intake flow path 220 and an intake port 124. The intake pipe 202 is roughly formed by an upstream intake pipe 202a located upstream of the compressor C and a downstream intake pipe 202b located downstream of the compressor C.

[0022] The exhaust system 300 includes a turbine T of a turbocharger TC, an exhaust pipe 302, a catalyst 304, a muffler 306, an A / F sensor 308, and a detection device 310. The exhaust pipe 302 is connected to the downstream side of a turbine housing 430. An exhaust flow path 320 is formed inside the exhaust pipe 302. The exhaust flow path 320 communicates with the exhaust port 126.

[0023] A turbine T of a turbocharger TC, an A / F sensor 308, a catalyst 304, and a muffler 306 are provided in this order from upstream to downstream in the exhaust pipe 302. The exhaust gas generated in the combustion chamber 118 after combustion is purified by the catalyst 304 as it passes through an exhaust flow path 320, and is discharged to the outside through the muffler 306.

[0024] The A / F sensor 308 is provided upstream of the catalyst 304 in the exhaust pipe 302. In the first embodiment, the A / F sensor 308 is disposed between the turbine T and the catalyst 304. The A / F sensor 308 detects the air-fuel ratio of the exhaust gas. A signal indicating the air-fuel ratio detected by the A / F sensor 308 is transmitted to the detection device 310. The detection device 310 derives the air-fuel ratio based on the signal indicating the air-fuel ratio obtained from the A / F sensor 308.

[0025] 2 is a schematic cross-sectional view of the blow-by gas recirculation device 400 according to the first embodiment. Before describing in detail the configuration of the blow-by gas recirculation device 400 according to the first embodiment, the configuration of the turbocharger TC will be described in detail below.

[0026] The turbocharger TC includes a center housing 410, a compressor housing 420, and a turbine housing 430. The center housing 410 is disposed between the compressor housing 420 and the turbine housing 430. The compressor housing 420 is connected to the left side of the center housing 410 by a fastening bolt (not shown). The turbine housing 430 is connected to the right side of the center housing 410 by a fastening bolt (not shown).

[0027] A bearing hole (not shown) is formed in the center housing 410, and the shaft 412 is rotatably inserted through the bearing hole. A bearing (not shown) is provided in the bearing hole, and the shaft 412 is rotatably supported by the bearing. A compressor impeller 422 is provided at the left end of the shaft 412. The compressor impeller 422 is disposed in the compressor housing 420. The compressor impeller 422 is rotatably housed in the compressor housing 420. A turbine impeller 432 is provided at the right end of the shaft 412. The turbine impeller 432 is disposed in the turbine housing 430. The turbine impeller 432 is rotatably housed in the turbine housing 430.

[0028] The compressor housing 420 is formed with an intake port 424 configured as a part of the intake passage upstream of the compressor impeller 422. The intake port 424 communicates with the air cleaner 204 (see FIG. 1). The compressor housing 420 is further formed with a diffuser passage 426 and a compressor scroll passage 428 configured as a part of the intake passage downstream of the compressor impeller 422. The diffuser passage 426 pressurizes the air. The diffuser passage 426 is formed in an annular shape on the outer periphery of the compressor impeller 422. The diffuser passage 426 communicates with the intake port 424 via the compressor impeller 422 on the radially inner side of the shaft 412.

[0029] The compressor scroll passage 428 is formed in an annular shape. The compressor scroll passage 428 is located, for example, radially outward of the shaft 412 relative to the diffuser passage 426. The compressor scroll passage 428 communicates with the intake passage 220 downstream of the compressor C and the diffuser passage 426. When the compressor impeller 422 rotates, air is sucked into the compressor housing 420 from the intake port 424. The sucked air is pressurized and accelerated in the process of flowing between the blades of the compressor impeller 422. The pressurized and accelerated air is pressurized in the diffuser passage 426 and the compressor scroll passage 428. The pressurized air is sent to the intake passage 220 downstream of the compressor C.

[0030] The turbine housing 430 has an exhaust port 434 formed as part of the exhaust flow path 320 on the downstream side of the turbine impeller 432. The exhaust port 434 is in communication with the catalyst 304. The turbine housing 430 also has a turbine scroll flow path 436 formed as part of the exhaust flow path 320 on the upstream side of the turbine impeller 432. The turbine scroll flow path 436 is formed in an annular shape around the outer periphery of the turbine impeller 432.

[0031] The exhaust gas discharged from the exhaust port 126 of the engine 100 is guided to the exhaust port 434 via the turbine scroll passage 436 and the turbine impeller 432. The exhaust gas guided to the exhaust port 434 rotates the turbine impeller 432 during the flow process.

[0032] The rotational force of the turbine impeller 432 is transmitted to the compressor impeller 422 via the shaft 412. When the compressor impeller 422 rotates, the air is pressurized as described above. The pressurized air is thus guided to the intake port 124 of the engine 100, and is supercharged by the turbocharger TC.

[0033] Next, a detailed configuration of the blow-by gas recirculation device 400 according to the first embodiment will be described with reference to Fig. 2. The blow-by gas recirculation device 400 includes a communication hole 500, an oil separator OS, a PCV valve VA, and a blow-by gas communication passage 600.

[0034] The communication hole 500 is formed in the walls of the cylinder block 102 (see FIG. 1) and the cylinder head 106, and is formed as a through hole penetrating the cylinder block 102 and the cylinder head 106. The communication hole 500 is a through hole formed in a position different from the cylinder bore 112, the intake port 124, and the exhaust port 126 of the engine 100. The communication hole 500 communicates the locker chamber 132 and the crank chamber 120 (see FIG. 1). Blow-by gas that flows out to the crank chamber 120 through a gap between the cylinder bore 112 and the piston 114 flows through the communication hole 500. The communication hole 500 can guide the blow-by gas in the crank chamber 120 to the locker chamber 132.

[0035] An oil separator OS is also provided in the locker chamber 132. The oil separator OS communicates with a communication hole 500, through which the blow-by gas in the crank chamber 120 is introduced. The oil separator OS separates the oil contained in the blow-by gas, and guides the blow-by gas from which the oil has been separated to a blow-by gas communication passage 600.

[0036] Further, the blow-by gas communication passage 600 is provided with a PCV valve VA. The PCV valve VA is configured to be able to switch between an open state and a closed state depending on the pressure difference between the blow-by gas communication passage 600 and the locker chamber 132. When the pressure in the blow-by gas communication passage 600 is greater than the pressure in the locker chamber 132, the PCV valve VA is in a closed state. When the PCV valve VA is in a closed state, it prevents the backflow of intake air from the intake port 424 to the locker chamber 132 through the blow-by gas communication passage 600. On the other hand, when the pressure in the blow-by gas communication passage 600 is less than the pressure in the locker chamber 132, the PCV valve VA is in an open state. When the PCV valve VA is in an open state, it allows the flow of blow-by gas from the locker chamber 132 to the intake port 424 through the blow-by gas communication passage 600. In the first embodiment, the PCV valve VA is disposed in a first communication passage 610, which will be described later. However, as long as it is disposed in the blow-by gas communication passage 600, the location of the PCV valve VA is not limited to the first communication passage 610.

[0037] The blow-by gas communication passage 600 connects the locker chamber 132 with the intake port 424, which is the intake passage 220 on the upstream side of the compressor impeller 422 in the compressor housing 420. The blow-by gas communication passage 600 includes a first communication passage 610, a second communication passage 620, a third communication passage 630, and a fourth communication passage 640.

[0038] The first communication passage 610 is formed in the wall of the cylinder head 106, and is formed as a through hole penetrating the cylinder head 106, separate from the intake port 124, the exhaust port 126, and the communication hole 500. The first communication passage 610 is formed at a position different from the intake port 124, the exhaust port 126, and the communication hole 500. The cylinder head 106 has a first connection surface S1 that connects to the turbine housing 430. The first communication passage 610 extends from the first connection surface S1 of the cylinder head 106 to the locker chamber 132, and opens to the first connection surface S1 and the locker chamber 132. When the cylinder head 106 and the turbine housing 430 are connected at the first connection surface S1, the exhaust port 126 (see FIG. 1) of the cylinder head 106 and the turbine scroll passage 436 of the turbine housing 430 communicate with each other.

[0039] The second communication passage 620 is formed in the wall of the turbine housing 430 and is formed as a through hole penetrating the turbine housing 430 separate from the exhaust port 434 and the turbine scroll passage 436. The second communication passage 620 is formed at a position different from the exhaust port 434 and the turbine scroll passage 436. The turbine housing 430 has a second connection surface S2 that connects with the first connection surface S1 of the cylinder head 106 and a third connection surface S3 that connects with the center housing 410. The second communication passage 620 extends from the second connection surface S2 to the third connection surface S3 and opens to the second connection surface S2 and the third connection surface S3. When the second connection surface S2 connects with the first connection surface S1 of the cylinder head 106 and the third connection surface S3 connects with the center housing 410, the second communication passage 620 communicates with the first communication passage 610 and the third communication passage 630.

[0040] The third communication passage 630 is formed in the wall of the center housing 410, and is formed as a through hole penetrating the center housing 410, separate from the oil passage and the bearing hole (not shown). The third communication passage 630 is formed at a position different from the oil passage and the bearing hole. The center housing 410 has a fourth connection surface S4 that connects with the third connection surface S3 of the turbine housing 430, and a fifth connection surface S5 that connects with the compressor housing 420. The third communication passage 630 extends from the fourth connection surface S4 to the fifth connection surface S5, and opens to the fourth connection surface S4 and the fifth connection surface S5. When the fourth connection surface S4 connects with the third connection surface S3 of the turbine housing 430 and the fifth connection surface S5 connects with the compressor housing 420, the third communication passage 630 communicates with the second communication passage 620 and the fourth communication passage 640.

[0041] The fourth communication passage 640 is formed in the wall of the compressor housing 420, and is formed as a through hole penetrating the compressor housing 420, separate from the intake port 424, the diffuser passage 426, and the compressor scroll passage 428. The fourth communication passage 640 is formed at a position different from the intake port 424, the diffuser passage 426, and the compressor scroll passage 428. The compressor housing 420 has a sixth connection surface S6 that connects to the fifth connection surface S5 of the center housing 410. The fourth communication passage 640 extends from the sixth connection surface S6 to the intake port 424, which is a part of the intake passage 220 on the upstream side of the compressor impeller 422, and opens to the sixth connection surface S6 and the intake port 424. When the sixth connection surface S6 connects to the fifth connection surface S5 of the center housing 410, the fourth communication passage 640 communicates with the third communication passage 630.

[0042] Here, when the turbocharger TC is supercharging, the pressure in the intake port 424, which is upstream of the compressor impeller 422, becomes negative. At this time, since the intake port 424 and the blow-by gas communication passage 600 are in communication with each other, the pressure in the intake port 424 becomes negative, and the pressure in the blow-by gas communication passage 600 also becomes negative. When the pressure in the blow-by gas communication passage 600 becomes negative, the pressure in the blow-by gas communication passage 600 becomes smaller than the pressure in the locker chamber 132. As a result, the PCV valve VA changes from a closed state to an open state, and the blow-by gas in the crank chamber 120 is returned to the intake port 424, i.e., the intake passage 220, through the communication hole 500, the oil separator OS, the PCV valve VA, and the blow-by gas communication passage 600. In this manner, the blow-by gas recirculation device 400 that recirculates the blow-by gas in the crank chamber 120 to the intake passage 220 is configured.

[0043] Meanwhile, North American regulations require that it is possible to detect not only the leakage of blow-by gas caused by the disconnection of the blow-by gas piping but also the leakage caused by the breakage of the blow-by gas piping. In order to satisfy the requirement, the blow-by gas recirculation device 400 of the first embodiment is configured not to have a blow-by gas piping for circulating the blow-by gas exposed to the outside of the engine 100, the intake system 200, the exhaust system 300, and the turbocharger TC. Instead of the blow-by gas piping, the first embodiment has a blow-by gas communication passage 600 formed as a through hole in the wall of the cylinder head 106, the wall of the turbine housing 430, the wall of the center housing 410, and the wall of the compressor housing 420. The blow-by gas communication passage 600 is in a positional relationship in which a sealed state is maintained when the cylinder head 106, the turbine housing 430, the center housing 410, and the compressor housing 420 are located at their fixed positions. In addition, the blow-by gas communication passage 600 is in a position where it is no longer sealed when the cylinder head 106, the turbine housing 430, the center housing 410, and the compressor housing 420 shift or move away from each other and become positioned differently from their normal positions.

[0044] 1 derives the air-fuel ratio based on a signal indicating the air-fuel ratio obtained from the A / F sensor 308, as described above. Now, assume that at least one of the connections between the cylinder head 106 and the turbine housing 430, between the turbine housing 430 and the center housing 410, and between the center housing 410 and the compressor housing 420 is disconnected. In that case, any of the first communication passage 610, the second communication passage 620, the third communication passage 630, and the fourth communication passage 640 of the blow-by gas communication passage 600 is disconnected, and the blow-by gas leaks to the outside.

[0045] However, at the same time, intake air and exhaust gas leak from the turbocharger TC to the outside, causing the output value of the A / F sensor 308 to change by a large amount equal to or greater than a predetermined value. Therefore, the detection device 310 can detect that the connection between the engine 100 and the turbocharger TC, or the connection between the components that make up the turbocharger TC, has been released, based on the amount of change in the output value of the A / F sensor 308. At the same time, the detection device 310 can detect that the connection of the blow-by gas communication passage 600 has been released, based on the amount of change in the output value of the A / F sensor 308. For example, when the amount of change in the output value of the A / F sensor 308 is equal to or greater than a predetermined value, the detection device 310 detects that the connection of the blow-by gas communication passage 600 has been released.

[0046] As described above, according to the first embodiment, it is possible to detect blow-by gas leakage with a simple configuration without requiring additional hardware configuration such as a crankcase pressure sensor or an ON-OFF valve to enable detection of blow-by gas leakage.

[0047] FIG. 3 is a schematic cross-sectional view of a blow-by gas recirculation device 400A according to the second embodiment. Components substantially equivalent to those of the blow-by gas recirculation device 400 of the first embodiment are denoted by the same reference numerals and will not be described. The configuration of the blow-by gas recirculation device 400A of the second embodiment is different from the configuration of the blow-by gas recirculation device 400 of the first embodiment in that an exhaust manifold 700 is provided between the cylinder head 106 and the turbine housing 430. In the first embodiment, the cylinder head 106 and the turbine housing 430 are directly connected to each other, whereas in the second embodiment, the cylinder head 106 and the turbine housing 430 are indirectly connected to each other via the exhaust manifold 700. The exhaust manifold 700 is provided between the cylinder head 106 and the turbine housing 430.

[0048] 3, the blow-by gas recirculation device 400A of the second embodiment includes a communication hole 500, an oil separator OS, a PCV valve VA, and a blow-by gas communication passage 600A. The configuration of the communication hole 500 is the same as that described in the first embodiment, and therefore the description thereof will be omitted.

[0049] The blow-by gas communication passage 600A connects the locker chamber 132 with the intake port 424, which is the intake passage 220 upstream of the compressor impeller 422 in the compressor housing 420. The blow-by gas communication passage 600 includes a first communication passage 610, a second communication passage 620, a third communication passage 630, a fourth communication passage 640, and a fifth communication passage 650.

[0050] The first communication passage 610 is formed in a wall portion of the cylinder head 106, and is formed as a through hole penetrating the cylinder head 106 separate from the communication hole 500. The cylinder head 106 has a first connection surface S11 that connects to the exhaust manifold 700. The first communication passage 610 extends from the first connection surface S11 of the cylinder head 106 to the locker chamber 132, and opens to the first connection surface S11 and the locker chamber 132. When the cylinder head 106 and the exhaust manifold 700 are connected at the first connection surface S11, the exhaust port 126 (see FIG. 1 ) of the cylinder head 106 communicates with the exhaust flow passage 320 formed in the wall portion of the exhaust manifold 700.

[0051] The fifth communication passage 650 is formed in the wall of the exhaust manifold 700, and is formed as a through hole penetrating the exhaust manifold 700 separate from the exhaust passage 320. The fifth communication passage 650 is formed at a position different from the exhaust passage 320. The exhaust manifold 700 has a seventh connection surface S12 that connects to the first connection surface S11 of the cylinder head 106, and an eighth connection surface S13 that connects to the turbine housing 430. The fifth communication passage 650 extends from the seventh connection surface S12 to the eighth connection surface S13, and opens to the seventh connection surface S12 and the eighth connection surface S13. When the seventh connection surface S12 connects to the first connection surface S11 of the cylinder head 106 and the eighth connection surface S13 connects to the turbine housing 430, the fifth communication passage 650 communicates with the first communication passage 610 and the second communication passage 620.

[0052] The second communication passage 620 is formed in the wall of the turbine housing 430 and is formed as a through hole penetrating the turbine housing 430 separate from the exhaust port 434 and the turbine scroll passage 436. The turbine housing 430 has a second connection surface S14 that connects to the eighth connection surface S13 of the exhaust manifold 700 and a third connection surface S3 that connects to the center housing 410. The second communication passage 620 extends from the second connection surface S14 to the third connection surface S3 and opens to the second connection surface S14 and the third connection surface S3. When the second connection surface S14 connects to the eighth connection surface S13 of the exhaust manifold 700 and the third connection surface S3 connects to the fourth connection surface S4 of the center housing 410, the second communication passage 620 communicates with the fifth communication passage 650 and the third communication passage 630.

[0053] The third communication passage 630 is formed in a wall of the center housing 410, and is formed as a through hole penetrating the center housing 410, separate from a bearing hole (not shown). The center housing 410 has a fourth connection surface S4 that connects with the third connection surface S3 of the turbine housing 430, and a fifth connection surface S5 that connects with the compressor housing 420. The third communication passage 630 extends from the fourth connection surface S4 to the fifth connection surface S5, and opens to the fourth connection surface S4 and the fifth connection surface S5. When the fourth connection surface S4 connects with the third connection surface S3 of the turbine housing 430 and the fifth connection surface S5 connects with the sixth connection surface S6 of the compressor housing 420, the third communication passage 630 communicates with the second communication passage 620 and the fourth communication passage 640.

[0054] The fourth communication passage 640 is formed in the wall of the compressor housing 420, and is formed as a through hole penetrating the compressor housing 420 separate from the intake port 424, the diffuser passage 426, and the compressor scroll passage 428. The compressor housing 420 has a sixth connection surface S6 that connects to the fifth connection surface S5 of the center housing 410. The fourth communication passage 640 extends from the sixth connection surface S6 to the intake port 424, which is a part of the intake passage 220 upstream of the compressor impeller 422, and opens to the sixth connection surface S6 and the intake port 424. When the sixth connection surface S6 connects to the fifth connection surface S5 of the center housing 410, the fourth communication passage 640 communicates with the third communication passage 630.

[0055] In this way, the blow-by gas recirculation device 400A of the second embodiment has the blow-by gas communication passage 600A. The blow-by gas communication passage 600A is formed as a through hole in the wall of the cylinder head 106, the wall of the exhaust manifold 700, the wall of the turbine housing 430, the wall of the center housing 410, and the wall of the compressor housing 420.

[0056] Therefore, as in the first embodiment described above, it is possible to detect blow-by gas leakage with a simple configuration without requiring additional hardware configuration such as a crankcase pressure sensor or an ON-OFF valve to enable detection of blow-by gas leakage.

[0057] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0058] TC Turbocharger 1 Engine System 10 Vehicles 100 Engine 106 Cylinder head 132 Locker Room 200 Intake system 300 Exhaust system 308 A / F sensor 310 Detection Device 400, 400A Blow-by gas recirculation device 410 Center Housing 420 Compressor Housing 430 Turbine Housing 500 communication hole 600, 600A Blow-by gas passage 610 1st communication passage 620 2nd communication passage 630 Third communication passage 640 4th connecting passage 650 5th passageway 700 exhaust manifold

Claims

1. an engine having a rocker chamber formed between a cylinder head and a rocker cover, a crank chamber formed by a crankcase, and a communication hole communicating the rocker chamber and the crank chamber; a turbocharger having a turbine housing, a compressor housing, and a center housing disposed between the turbine housing and the compressor housing; a blow-by gas communication passage formed as a through hole in a wall portion of the cylinder head, the turbine housing, the center housing, and the compressor housing, and connecting the locker chamber with an upstream side of a compressor impeller of an intake flow passage in the compressor housing; A blow-by gas recirculation device equipped with a blow-by gas recirculation system.

2. The blow-by gas communication passage is a first communication passage formed as a through hole in a wall portion of the cylinder head and extending from a first connection surface where the cylinder head is connected to the turbine housing to the locker room; a second communication passage formed as a through hole in a wall portion of the turbine housing and extending from a second connection surface at which the turbine housing is connected to the cylinder head to a third connection surface at which the turbine housing is connected to the center housing; a third communication passage formed as a through hole in a wall portion of the center housing and extending from a fourth connection surface at which the center housing is connected to the turbine housing to a fifth connection surface at which the center housing is connected to the compressor housing; a fourth communication passage formed as a through hole in a wall portion of the compressor housing and extending from a sixth connection surface where the compressor housing is connected to the center housing to an upstream side of the compressor impeller in the intake flow path; Including, The blow-by gas recirculation device according to claim 1.

3. an exhaust manifold provided between the cylinder head and the turbine housing, The blow-by gas communication passage is a fifth communication passage formed as a through hole in a wall portion of the exhaust manifold and connecting the first communication passage and the second communication passage; The blow-by gas recirculation device according to claim 2.

4. an exhaust pipe connected to a downstream side of the turbine housing; An A / F sensor provided in the exhaust pipe; a detection device that detects, based on an output value of the A / F sensor, that the connection of the blow-by gas communication passage has been released; Equipped with The blow-by gas recirculation device according to any one of claims 1 to 3.

Images