Exhaust structure

Abstract

An exhaust structure is provided with an exhaust manifold, and a supercharger having a turbine housing. The turbine housing is provided with an inflow port interconnected with the exhaust manifold, a housing member in which a space for housing turbine blades is formed, and an inflow port in which an inflow passage communicating from the inflow port through the housing space is formed. A sensor mounting part is formed in the inflow port, and a throttle member is formed such that the width thereof in an aligning direction of cylinders gradually decreases from the inflow port toward the sensor mounting part. With this configuration, the accuracy of detecting the combustion state of the cylinders can be increased.

Claims

1. An exhausting structure for an internal combustion engine including a plurality of cylinders aligned in an aligning direction, comprising: an exhaust manifold including a collector to collect exhaust gases exhausted from the cylinders; and a supercharger including a turbine housing connected to the exhaust manifold, the turbine housing comprising: an inflow port communicating with the collector; a blade housing including a blade space to house a turbine having turbine blades; and an inflow member, which is a conduit, including an inflow passage formed to communicate from the inflow port to the blade space, wherein the inflow member comprises a sensor mount part to mount a sensor to detect a state of the exhaust gas in the inflow passage, and a tapered portion of the conduit having a width in the aligning direction of the cylinders decreasing as going from the inflow port to the blade space sensor mount part, are formed, wherein a center of the sensor mount part is offset in the aligning direction by a predetermined distance relative to a center of a width of the inflow port and disposed on one side the center of the width of the inflow port in the aligning direction of the cylinders, and wherein the tapered portion has a first wall on the one side of the center of the width of the inflow port and a second wall on an another side of the center of the inflow port, wherein the first wall is flat and a width from the second wall to an axis through the center of the sensor mount part perpendicular to the aligning direction decreases from the inflow port to the sensor mounting part, the exhausting structure further comprising an outflow port, and a first connecting member, wherein the turbine housing further comprises: an outflow passage communicating from the blade space to the outflow port and a waste gate passage communicating from the inflow passage to the outflow passage; and a waste gate valve, installed at the first connecting member, to adjust a flow rate of the exhaust gas in the waste gate passage; and wherein the first connecting member connects the inflow passage to the waste gate passage on a downstream side in a flowing direction of the exhaust gas from the sensor mount part; and wherein the waste gate valve is disposed on the another side of the center of the width of the inflow port in the aligning direction.

2. The exhausting structure as claimed in claim 1, further comprising a thermal insulation cover covering at least a part of the turbine housing, wherein the thermal insulation cover includes a ventilation air-guide-port which opens in the thermal insulation cover.

3. The exhausting structure as claimed in claim 2, wherein the internal combustion engine is mounted on a vehicle, and wherein the ventilation air-guide-port opens in a downward direction of the vehicle.

4. The exhausting structure as claimed in claim 1, wherein the exhaust manifold is installed in a cylinder head of the internal combustion engine, wherein an exhaust emission control device is installed on the another side of the center of the inflow port in the aligning direction of the turbine housing, wherein a second connecting passage provided between the blade housing and the exhaust emission control device curves from the aligning direction to an axial direction of the cylinders, and wherein the exhaust emission control device extends along the axial direction.

5. The exhausting structure as claimed in claim 1, wherein the supercharger comprises the turbine housing and a compressor housing connected to an intake air passage, wherein the turbine housing and the compressor housing are arranged side by side in the aligning direction; and the compressor housing disposed on the another side of the center of the inflow port in the aligning direction.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a drawing of an exhaust structure according to an embodiment of the present invention, viewed from a forwardly obliquely upward direction.

(2) FIG. 2 is a schematic drawing of the exhaust structure according to the embodiment of the present invention.

(3) FIG. 3 is a drawing of the exhaust structure according to the embodiment of the present invention, viewed from a forwardly obliquely downward direction.

(4) FIG. 4 is a drawing of the exhaust structure according to the embodiment of the present invention, viewed from a front direction.

(5) FIG. 5 is a side view of an air-guide-port in a thermal insulation cover according to the embodiment of the present invention.

MODES FOR CARRYING OUT INVENTION

(6) An embodiment of the present invention is described in detail below with reference to drawings.

(7) An exhaust structure according to the embodiment of the present invention is described below in a case where the exhaust structure according to the present invention is applied to an internal combustion engine (engine).

(8) In the below description, a front-rear direction agrees with front and rear in a travelling direction of a vehicle, and left-right direction is a left-right direction when an internal combustion engine is viewed from a front direction of the vehicle. Upstream and downstream in the below description are upstream and downstream in flowing direction of the air and the exhaust gas.

(9) As illustrated in FIG. 1, an internal combustion engine 1 has four cylinders 2 arranged in the left-right direction (aligning direction AD). Each of the four cylinders 2 has an axis extending in the vertical direction.

(10) As shown in FIG. 2, an intake port 2a of each of the four cylinders 2 is connected to an intake air passage 10. An intercooler 11 is provided at an intermediate portion of the intake air passage 10.

(11) An exhaust structure 3 includes an exhaust manifold 20 connected to exhaust ports 2b of the four cylinders 2, a supercharger 30 connected to the intake air passage 10 and the exhaust manifold 20, and an exhaust emission control device 60 connected to the supercharger 30.

(12) The exhaust manifolds 20 includes a collector 21 for collecting exhaust gas exhausted by respective the four cylinders 2. The exhaust manifolds 20 are installed in a cylinder head 1a.

(13) The supercharger 30 includes a compressor housing 40 and a turbine housing 50 in which the compressor housing 40 and the turbine housing 50 are arranged side by side in the left-right direction (See FIG. 1).

(14) In the compressor housing 40, a housing space 42a is formed. In the housing space 42a, compressor blades 41 are housed. Further, the housing space 42a is connected to upstream and downstream sides of the intake air passage 10.

(15) The turbine housing 50 includes an inflow port 50a communicated with the collector 21 of the exhaust manifolds 20, a housing 52 in which a housing space 52a is formed, an inflow member 53 communicating from the inflow port 50a to the housing space 52a, the outflow member 54 communicating from the housing space 52a to an outflow port 50b, and a waste gate passage 55 communicating from an inflow passage 53a to the outflow passage 54a.

(16) In the housing space 52a of the housing 52, turbine blades 51 are housed. The turbine blades 51 are connected to the compressor blades 41 with a connecting shaft 31, so that the compressor blades 41 rotate interlockingly with rotation of the turbine blades 51.

(17) In the waste gate passage 55, a waste gate valve 56 is installed. The waste gate valve 56 is a valve opened and closed by a control device (not shown).

(18) In the supercharger 30, the exhaust gas exhausted from each of the four cylinders 2 flows into the housing space 52a through the inflow passage 53a of the turbine housing 50 and rotates the turbine blades 51 by the exhaust gas. The compressor blades 41 rotate interlockingly with the rotation of the turbine blades 51, so that air is sucked into the housing space 42a of the compressor housing 40 from an upstream side of the intake air passage 10. Further, the pressurized air is exhausted to a downstream side of the intake air passage 10 from the housing space 42a of the compressor housing 40 to supply a pressurized air is supplied to each of the four cylinders 2.

(19) It is noted that there may be a case where a supercharged pressure of the air supplied to each of the four cylinders 2 from the compressor housing 40 increases more than the demand due to increase in the rotation speed of the turbine blades 51 when the internal combustion engine 1 runs at a high rotation speed. In this case, the waste gate valve 56 is opened to allow a part of the exhaust gas in the inflow passage 53a to flow into the outflow passage 54a through the waste gate passage 55. This decreases a quantity of the exhaust gas flowing into the housing space 52a from the inflow passage 53a to decrease the rotation speeds of the turbine blades 51 and the compressor blades 41, so that the supercharged pressure of air supplied to each of the four cylinders 2 from the compressor housing 40 decreases.

(20) In the turbine housing 50, as shown in FIG. 1, a fixing flange 57 is formed to be installed on a front face of the cylinder head 1a. At a bonding surface of the fixing flange 57, the inflow port 50a opens.

(21) As shown in FIG. 3, at upper edges and lower left corner and lower right corner of the fixing flange 57, a plurality of fixing holes 57a penetrate the fixing flange 57. The turbine housing 50 is fixed to the cylinder head 1a by screwing bolts penetrated through the fixing holes 57a with thread screw holes of the cylinder head 1a (see FIG. 1).

(22) As shown in FIG. 5, the inflow member 53 protrudes forward from the inflow port 50a and curved downward like spiral.

(23) In the inflow member 53, at a substantially intermediate part between the inflow port 50a and the housing space 52a, a sensor mounting part 53b, to which a sensor 58 is fixed, is formed. In an outside wall of the sensor mounting part 53b, a fixing hole through which the sensor 58 is inserted, is formed.

(24) A width of the sensor mounting part 53b in the left-right direction is, as shown in FIG. 1, decreased than a width W2 of the inflow port 50a in the left-right direction. At a center in the left-right direction of the sensor mounting part 53b, a fixing hole is formed.

(25) A center of the sensor mounting part 53b in the left-right direction is disposed on a left side of the center of the inflow port 50a in the left-right direction. In FIG. 1, the center of the sensor mounting part 53b in the left-right direction is disposed on a line L2 which extends in an extending direction of the inflow passage 53a and is offset D1 on a left side of a line L1 passing a center of the inflow port 50a in the left-right direction.

(26) A left edge of the inflow passage 53a in the sensor mounting part 53b and a left end part of the inflow port 50a are disposed at the same places in the left-right direction.

(27) In the inflow member 53, between the inflow port 50a and a tapered portion sensor mounting part 53b the tapered portion 53c is formed.

(28) The tapered portion 53c has a width W1 in the left-right direction gradually decreases as going from the inflow port 50a to the sensor mounting part 53b. In other words, the tapered portion 53c has a width W1 in the left-right direction gradually decreasing as going to a downstream side of the inflow passage 53a.

(29) In this embodiment a right side part 53d of the inflow member 53 is successively offset (W2W1) to the left side as going to the sensor mounting part 53b from the inflow port 50a of the inflow member 53 to form the tapered portion 53c. In addition, a left side part 53e of the inflow member 53 is formed in flat and has no offset (W2/2).

(30) The inflow member 53 has the width W1 in the left-right direction decreasing and offset to a left side as going from the inflow port 50a to the sensor mounting part 53b. This forms a space on a right region of the sensor mounting part 53b.

(31) An inner face on the right side of the inflow passage 53a in the tapered portion 53c is successively offset (W2W1) on the left side of the inflow passage 53a of the tapered portion 53c, corresponding to an outer shape of the tapered portion 53c as going from the inflow port 50a to the sensor mounting part 53b. Accordingly, the inflow passage 53a has the width W1 of the inflow passage 53a in the left-right direction gradually decreasing as going from the inflow port 50a to the sensor mounting part 53b.

(32) The sensor 58 is, for example, an A/F sensor to detect a fuel-air mixture ratio of the exhaust gas in the inflow passage 53a. The sensor 58 is inserted through a mounting hole of the sensor mounting part 53b and a detecting part protrudes in the inflow passage 53a and a base part protrudes outside of the inflow member 53. A detection result of the sensor 58 is applied to a control device (not shown).

(33) As shown in FIG. 2, in the inflow member 53, a connecting member 53f for connecting the inflow passage 53a and the waste gate passage 55 is formed on a downstream side of the sensor mounting part 53b. At the connecting member 53f, the waste gate valve 56 is installed. The waste gate valve 56 is disposed at a space on the right side of the inflow member 53 as shown in FIG. 1.

(34) At a right side part of the inflow member 53, a connecting flange 50c having a connecting surface having a normal line extending in the left-right direction is formed. On the connecting surface of the connecting flange 50c, the outflow port 50b (see FIG. 2) opens.

(35) In the embodiment, the inflow member 53 is offset to the left side as going from the inflow port 50a to the sensor mounting part 53b. Accordingly, in this embodiment, the connecting flange 50c is more offset to the left side than a position of the connecting flange in the case where the sensor mounting part 53b is positioned at a center in the left-right direction of the inflow port 50a.

(36) As shown in FIG. 4, provided in front of a cylinder block 1b is the exhaust emission control device 60. The exhaust emission control device 60 is a catalytic converter provided between the turbine housing 50 and an exhaust pipe 4.

(37) Provided between the turbine housing 50 and the exhaust emission control device 60 is a connecting member 59. Formed in the connecting member 59 is a connecting passage 59a.

(38) The connecting passage 59a is, as shown in FIG. 2, a flow passage connecting the outflow port 50b of the turbine housing 50 and the inflow port of the exhaust emission control device 60. The connecting passage 59a curves, as shown in FIG. 4, at a substantially right angle as going in the left-right direction (in an aligning direction AD of the cylinders 2) and turns downward (in an axial direction of the cylinders 2).

(39) A lower end of a part of the connecting passage 59a extended in the vertical direction is connected to the exhaust emission control device 60 which extends in the vertical direction (the axial direction of the cylinders 2).

(40) The exhaust structure 3 according to the embodiment is, as shown in FIG. 5, provided with a thermal insulation cover 70 covering a front portion of the turbine housing 50. The thermal insulation cover 70 prevents heat generated in the turbine housing 50 from transmitting to various components arranged around the turbine housing 50.

(41) A front face of the thermal insulation cover 70 has a plurality of ventilation air-guide-ports 71 open. The ventilation air-guide-port 71 includes a cover portion 71a partially covering the opening of ventilation air-guide-port 71, but opens at the lower side of the cover portion 71a. In other words, the ventilation air-guide-port 71 opens downwardly.

(42) An upper surface of the thermal insulation cover 70 has a through hole 72 opening to allow the sensor 58 to be inserted therethrough. Further, in the sensor 58, a sensor cover 58b having a hollow cylindrical shape is installed to cover a part of the sensor 58 protruding from the turbine housing 50.

(43) Formed between an outer surface of the sensor cover 58b and an inner circumferential surface of the through hole 72 of the thermal insulation cover 70 is a gap 73. The ambient air flowing into the thermal insulation cover 70 through the ventilation air-guide-ports 71 is discharged to the external through the gap 73 between the sensor cover 58b and the through hole 72 and a gap between the turbine housing 50 formed in a direction vertical to the paper face of FIG. 5 (not shown).

(44) The exhaust structure 3 as described above can increase a flow velocity of the exhaust gas by allowing the exhaust gas discharged from the cylinder 2 to flow into the tapered portion 53c as shown in FIG. 1. This accelerates exchanging of the exhaust gas around detection range of the sensor 58, so that the state of the exhaust gas for each of the cylinders 2 can be rapidly detected.

(45) In addition, the exhaust gas discharged from the cylinders is funneled by the tapered portion 53c, which prevents the exhaust gas from spreading.

(46) Further, when the waste gate valve 56 is opened, the exhaust gas flows into the waste gate passage 55 (see FIG. 2) on a downstream side of the sensor 58, which prevents the sensor 58 from influencing on the detection accuracy of the exhaust gas.

(47) Accordingly, in the exhaust structure 3 according to the embodiment, the state of the exhaust gas of each of the cylinders 2 can be accurately detected with the sensor 58, which results in increase in the detection accuracy of the burning state of each of the cylinders 2.

(48) In the exhaust structure 3 according to the embodiment, the sensor mounting part 53b is offset on the left side of the center in the left-right direction of the inflow port 50a by a predetermined distance D1 to secure a space on a right side of the inflow member 53.

(49) Further, at a space secured on a right side of the inflow member 53, the waste gate valve 56 is provided, so that an installation space for the supercharger 30 becomes narrower.

(50) Further, as shown in FIG. 4, this configuration allows the connecting member 59 connected to the right side part of the turbine housing 50 to be offset to the left side. This allows the connecting passage 59a between the turbine housing 50 and the exhaust emission control device 60 to be curved at a substantially right angle downwardly from the left-right direction, so that the exhaust emission control device 60 extends vertically. Accordingly, a pressure loss in the exhaust gas in the connecting passage 59a can be made small, so that an exhaust efficiency can be increased, while the exhaust emission control device 60 is housed within a width in the left-right direction of the internal combustion engine 1.

(51) Further, as shown in FIG. 3, the connecting flange 50c can be disposed on the left side of the fixing hole 57a at a right lower corner of the fixing flange 57, so that a space can be provided in front of the fixing hole 57a. When a bolt inserted into the fixing hole 57a is fixed to the cylinder head 1a (see FIG. 1), this allows the bolt to be fastened after inserting a tool in front of the cylinder head 1a from a side of the internal combustion engine 1. As described above, because the tool can be arranged from a side of the internal combustion engine 1 in line, so that the fixing flange 57 can be installed in the cylinder head 1a and an operation efficiency can be enhanced.

(52) Further, the exhaust emission control device 60 is disposed near the cylinder block 1b and the exhaust gas at a high temperature discharged by the supercharger 30 directly flows into the exhaust emission control device 60. Accordingly, a temperature of the catalyst in the exhaust emission control device 60 can be increased.

(53) As shown FIG. 5, the exhaust structure 3 according to the embodiment, the thermal insulation cover 70 covering the turbine housing 50 has the ventilation air-guide-ports 71 open, which prevents a temperature increase in the sensor 58 by introducing the ambient air into the thermal insulation cover 70. Further the ventilation air-guide-port 71 in the thermal insulation cover 70 opens in a downward direction of the vehicle, which prevents a temperature increase in the sensor 58 in the thermal insulation cover 70 without losing the heat insulating effect toward the front thereof with the thermal insulation cover 70.

(54) As the embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment, but may be appropriately modified without departure of the spirit of the subject matter of the present invention.

(55) The tapered portion 53c according to the embodiment, as shown in FIG. 1, the right side part 53d of the inflow member 53 is successively offset to the left as going to the sensor mounting part 53b from the inflow port 50a.

(56) However, it is possible to form the tapered portion by successively offset the left side part 53e of the inflow member 53 to the right side as going from the inflow port 50a to the sensor mounting part 53b.

(57) Further, it is allowed to form the tapered portion by successively offsetting both the right side part 53d and the left side part 53e of the inflow member 53 to the inner side as going from the inflow port 50a to the sensor mounting part 53b.

(58) In the embodiment, the exhaust manifold 20 is provided inside of the cylinder head 1a, but may be provided outside the cylinder head 1a.

(59) The inflow member 53 of the turbine housing 50 is formed, as shown in FIG. 5, having a downward spiral, but may have an upward spiral, or horizontally.

(60) The sensor 58 according to the embodiment detects, as shown in FIG. 1, the air-fuel ratio of the exhausted gas in the inflow passage 53a, but other various types of sensors can be used to detect the state of the temperature or a quantity of oxygen of the exhaust gas.

(61) In the embodiment, though the axial direction of the cylinders 2 is arranged in the vertical direction, but the direction is not limited.

DESCRIPTION OF REFERENCE SYMBOLS

(62) 1 Internal Combustion Engine 1a Cylinder Head 1b Cylinder Block 2 Cylinder 3 Exhaust Structure 10 Intake Air Passage 11 Intercooler 20 Exhaust Manifold 21 Collector 30 Supercharger 31 Connecting Shaft 40 Compressor Housing 41 Compressor Blades 42a Housing Space 50 Turbine Housing 50a Inflow Port 50b Outflow Port 50c Connecting Flange 51 Turbine Blades 52 Housing Member 52a Housing Space 53 Inflow Member 53a Inflow Passage 53b Sensor Mounting Part 3c Tapered portion 53f Connecting Member 54 Outflow Member 54a Outflow Passage 55 Waste gate Passage 56 Waste gate Valve 57 Fixing Flange 58 Sensor 59 Connecting Member 59a Connecting Passage 60 Exhaust Emission Control Device 70 Thermal Insulation Cover 71 Ventilation air-guide-port