CHARGER AND A VEHICLE

TECHNICAL FIELD

The invention relates to a conduit connection assembly, a turbine inlet conduit for a turbo charger for an internal combustion engine, a turbo charger for an internal combustion engine, and a vehicle provided with conduit connection assembly. BACKGROUND

In typical vehicles, conduits provide air to an internal combustion engine of the vehicle, and guide exhaust gases from the engine. Engine operation may cause pulsations in such conduits, which may have detrimental effects to devices in the conduits or the operation of the engine. This problem is particularly pronounced where the engine is provided with a turbo charger, and the conduits are located where high pressures occur during turbo charger operation.

US2013111901A1 describes for a turbo charged engine a pulsation absorption device with a resonator, a diaphragm, or a bladder, in order to avoid compressor surge which according to US2013111901A1 might be caused by pulsations in the exhaust flow. FR2879689A1 describes a damping chamber on a compressor side of a turbo charger for reducing pressure pulses from the compressor. However, such known pulsation damping devices are complex and therefore add cost to the vehicle. Also, said FR2879689A1 does not provide any relief of pressure pulses on the turbine side of the turbo charger. Where a device according to said US2013111901A1 is placed on the turbine side, upstream of a turbo charger, the reduced peak pressure can reduce the performance of the turbo charger.

SUMMARY

It is an object of the invention to reduce the effect of pressure pulses in conduits, in particular conduits of, or connected to, an internal combustion engine. It is a further object of the invention to reduce the effect of pressure pulses in conduits connecting an engine block of an internal combustion engine to a turbo charger. These objects are reached with a conduit connection assembly comprising a first conduit part and a second conduit part, adapted to be assembled to form a conduit connection delimiting a fluid conducting volume, wherein one of the first and second conduit parts presents a connection surface adapted to face the other of the first and second conduit parts, wherein a pressure reducing volume is at least partly formed in the connection surface.

Providing the pressure reducing volume at least partly formed in the connection surface allows for local pressure pulse reduction or damping to reduce pressure pulse effects to the connection. For example, where a seal or gasket is provided at the connection, the wear of the seal may be reduced, so that the life of the seal may be increased, and/or the use of simpler and less costly seals may be allowed. In particular, where the connection is provided in a conduit connecting an engine block to a turbo charger, whereby the connection is exposed to a high pressure during turbo charger operation, the pressure reducing volume formed in the connection surface will considerably reduce the effects of pressure pulses to a sealing abutment of the connection. E.g., where such an abutment includes a gasket, the invention may allow for a cheap one layer stainless steel gasket to be used instead of an expensive three layer nickel-chromium alloy gasket.

Also, the local pressure pulse reduction aimed at reducing pressure pulse effects on the connection, makes it possible to retain the pressure pulses in the fluid conducting volume, which is beneficial to a turbo charger operation where the connection is provided upstream of a turbine charger, on the turbine side thereof.

As exemplified further below, to effectively reduce peak pressure impact on the connection, the pressure reducing volume is preferably specifically adapted to reduce pressure pulses from the fluid conducting volume.

Preferably, the pressure reducing volume is at least partly delimited by the first conduit part as well as the second conduit part. This allows for simple manufacturing of the pressure reducing volume, since the connection surfaces may be easily accessible for some of the manufacturing measures before assembly of the conduit connection assembly, leaving the completion of a substantially enclosed pressure reducing volume to be provided as a result of the assembly. Preferably, the pressure reducing volume is at least partly formed by a depression in the connection surface. By forming at least a part of the pressure reducing volume by such a depression, the provision of the pressure reducing volume during manufacturing may be facilitated.

Preferably, the pressure reducing volume presents a cavity being close loop shaped, e.g. ring shaped, and extending around the fluid conducting volume. Thereby, the cavity can be arranged to be distributed along a sealing abutment of the conduit connection assembly, thereby providing a local and effective protection of the abutment against pressure pulses on the fluid conducting volume.

Preferably, the conduit connection assembly may present a slot adapted to provide a communication between the fluid conducting volume and the pressure reducing volume. Such a slot will together with the pressure reducing volume contribute to the reduction of pressure pulses from the fluid conducting volume. Preferably, the first and second conduit parts are adapted to form the slot in their assembled state. Thereby, the slot may be provided in a simple manner during manufacturing by assembling the first and second conduit parts.

Preferably, the pressure reducing volume is 5,000 to 50,000 times larger than a volume occupied by the slot. Such a high ratio of the volume of the pressure reducing volume and the volume occupied by the slot will effectively reduce the peak pressures of the pressure pulses in the first fluid conducting volume, and may thereby reduce pressure peak exposure to a sealing abutment of the conduit connection assembly. Preferably, where the pressure reducing volume presents a cavity, the cavity and the slot being closed loop shaped, e.g. ring shaped, and extending around the fluid conducting volume, the cavity presents, in a cross-section perpendicular to a circumferential direction of the fluid conducting volume, a cross-sectional area which is 100,000 to 1,000,000 times larger than the slot width squared. This will further secure a reduction peak pressure exposure to a sealing abutment of the conduit connection assembly. It should be noted that the

circumferential direction of the fluid conducting volume is preferably defined by the local direction of a gas flow in the fluid conducting volume. The local direction of the gas flow is the direction of the gas flow at the conduit connection. The circumferential direction is a direction which is perpendicular to an axial direction of the gas flow, and perpendicular to a radial direction of the gas flow.

Preferably, the slot extends at least partly in an axial direction of the conduit connection assembly in its assembled condition. An axial extension of the slot will facilitate production with high tolerance requirements on the slot. In some embodiments however, the slot extends at least partly in a radial direction of the conduit connection assembly in its assembled condition. It should be noted that the axial direction of the conduit connection assembly is preferably defined as the local direction of a gas flow in the fluid conducting volume, at the conduit connection. The radial direction of the conduit connection assembly is perpendicular to said axial direction.

Preferably, the width of the slot is 0.001-1 mm, preferably 0.005-0.5 mm, more preferably 0.01-0.1 mm. Such a relatively low slot width will, in connection to a relatively large pressure reducing volume, provide a particularly effective peak pressure damping, especially where the conduit connection assembly is provided in an exhaust or inlet system of a vehicle.

Preferably, the slot extends around the fluid conducting volume, and the length of the slot, as seen in a cross-section perpendicular to a circumferential direction of the fluid conducting volume, is at least 0.5 mm, preferably at least 1 mm, more preferably at least 2 mm. Such a slot length will provide a dimension of the slot facilitating manufacturing, while retaining an effective pressure pulse damping contribution.

Preferably, the slot extends around the fluid conducting volume in the circumferential direction. The slot may present the shape of a closed loop. The slot may be e.g. ring shaped. The width of the slot may be defined as the smallest dimension of the slot. The length of the slot may be the dimension of the slot following the shortest distance of communication provided by the slot, from the fluid conducting volume to the pressure reducing volume. Preferably, the pressure reducing volume is at least partly formed by a cavity, and the first and second conduit parts are adapted to form, in their assembled state, a sealing abutment radially outside the cavity. Thereby, the pressure reducing volume can provide a barrier to the sealing abutment to protect it against pressure pulses. The cavity and the sealing abutment may extend around the fluid conducting volume, preferably forming respective closed loops. The cavity may be at least partly formed by a depression in the connection surface.

The first and second conduit parts are adapted to form the sealing abutment by directly contacting each other. Thus, a sealing element, such as a gasket, is omitted, which is made possible by the pressure reducing volume reducing pressure pulses, and this will reduce complexity and cost of the conduit connection assembly.

Alternatively, the first and second conduit parts might be adapted to form the sealing abutment by a sealing element, which might be a gasket, between the first and second conduit parts. As mentioned, in such embodiments, the invention makes it possible to use simpler and less costly sealing elements.

Preferably, the first conduit part is a turbine inlet conduit of a turbo charger for an internal combustion engine. The second conduit part might be an exhaust gas conveying part, e.g. an exhaust gas outlet manifold, adapted for conveying exhaust gases from an internal

combustion engine. Thereby, the invention will be implemented to provide an effective protection of a sealing abutment at the taxing environment of the exhaust gas stream with the pressure pulses from the engine.

The invention may also be implemented to provide an effective protection of a sealing abutment at other locations with challenging environments, e.g. with high pulsating pressures. The first conduit part might be a compressor outlet conduit of a turbo charger for an internal combustion engine. The second conduit part might be an air inlet conduit for an internal combustion engine. The first conduit part can be an intercooler for an air inlet of an internal combustion engine. The first conduit part might be an internal combustion engine and the second conduit part can be an air inlet manifold or an exhaust gas outlet manifold. The first conduit part might be a turbo compound unit. Preferably, the pressure reducing volume presents a draining connection. Thereby it will be possible to reduce the exposure of a sealing abutment in the conduit connection assembly to a high mean pressure in the fluid conducting volume. In combination with a narrow slot as described above, e.g. with a width of 0.001-1 mm, preferably 0.005-0.5 mm, more preferably 0.01-0.1 mm, any diversion of a flow in the fluid conducting volume into the draining connection will be kept advantageously small. In combination with a cavity as described above, presenting a closed loop shape, e.g. by being ring shaped, and extending around the fluid conducting volume, a homogenous and rapid evacuation of fluid conducting volume pressure affecting the sealing abutment can be provided.

Preferably, the fluid conducting volume is a first fluid conducting volume, the conduit connection assembly further being adapted to present, in its assembled state, a second fluid conducting volume, and the draining connection is adapted to provide a communication between the first and second fluid conducting volumes. Preferably, where the pressure reducing volume comprises a cavity as described above, the draining connection is adapted to provide a communication between the cavity and the second fluid conducting volume. The second fluid conducting volume might present a pressure which is lower than that of the first fluid conducting volume. For example, the first fluid conducting volume might be adapted to communicate with an internal combustion engine, whereby during operation of the internal combustion engine, the pressure in the first conducting volume is higher than the pressure in the second conducting volume. This might be due to the first fluid conducting volume being, in the assembled state of the assembly, partly formed by a turbine inlet conduit of a turbo charger for an internal combustion engine, and the second fluid conducting volume being at least partly formed by a turbine outlet conduit of the turbo charger. Thereby, due to the draining connection, the sealing abutment of the conduit connection assembly will be exposed to substantially the same pressure as that in the second fluid conducting volume. This will considerably reduce the high pressure exposure to the sealing abutment. This lower pressure will also contribute to reducing or eliminating the exposure of the sealing abutment to pressure pulses in the first fluid conducting volume. At the same time, the high pressure and the pressure pulses may be retained in the first fluid conducting volume, thereby retaining a high turbo charger efficiency.

It should be noted that preferably, where the pressure reducing volume comprises a cavity, the cavity in completely enclosed, apart from the communication with the slot and, where the pressure reducing volume presents a draining connection, the communication with the draining connection.

The objects are also reached with a turbine inlet conduit for a turbo charger for an internal combustion engine, wherein the turbine inlet conduit is adapted to be assembled to another conduit part, and presents a connection surface adapted to face the other conduit part, wherein a depression is formed in the connection surface whereby the depression is adapted to form, when the turbine inlet conduit is assembled to the other conduit part, at least a part of a pressure reducing volume.

Preferably, the depression presents a closed loop shape, e.g. by being ring shaped, and is adapted to extend around a fluid conducting volume formed by the turbine inlet conduit and the other conduit part in their assembled condition. The objects are also reached with a turbo charger for an internal combustion engine, comprising a turbine inlet conduit according to any embodiment described or claimed herein, the turbo charger further comprising a turbine outlet conduit, and a draining connection an adapted to provide a communication between the depression and the turbine outlet conduit. The objects are also reached with a vehicle provided with a conduit connection assembly according to any embodiment described or claimed herein, a turbine inlet conduit according to any embodiment described or claimed herein, or a turbo charger according to any

embodiment described or claimed herein. DESCRIPTION OF DRAWINGS

Below embodiments of the invention will be described with reference to the drawings in which

fig. 1 shows a partially sectioned side view of a vehicle in the form of a truck, - fig. 2 shows schematically components of an internal combustion engine of the

vehicle in fig. 1, provided with a turbo charger,

fig. 3 shows a cross- sectional view, with the section oriented as indicated with the line III-III in fig. 2,

fig. 4 shows a detail of fig. 3,

- fig. 5 shows a perspective view of a part shown in fig. 3,

fig. 6 shows a detail of fig. 4,

fig. 7 shows a perspective view of an exhaust manifold and a turbo charger in an alternative embodiment of the invention, fig. 8 shows a perspective, partly sectioned view of a part of the turbo charger in fig. 7,

fig. 9 shows a perspective view of a portion of the part shown in fig. 8,

fig. 10 shows a perspective, partly sectioned view of a part of the exhaust manifold and a part of the turbo charger in fig. 7,

fig. 11 shows a detail of fig. 10,

fig. 12 shows schematically components of an internal combustion engine in a further embodiment of the invention, and

fig. 13 and fig. 14 show views corresponding to the views of fig. 3 and fig. 4, respectively, with yet another embodiment of the invention.

DETAILED DESCRIPTION

Fig. 1 shows a vehicle in the form of a truck with an internal combustion engine 1 comprising an engine block 101 with a number of cylinders, in this example six. As can be seen in fig. 2, the engine 1 is provided with a turbo charger 2 adapted to provide pressurised inlet air to an inlet manifold 301 via a first charged air conduit 302, an intercooler 303 and a second charged air conduit 304. An air admission conduit 305 is adapted to guide air to the turbo charger 2. The turbo charger 2 is adapted to be driven with a flow of exhaust gases provided via an exhaust manifold 401 of the engine. Downstream of the turbo charger 2 an exhaust conduit 5 is provided.

The turbo charger comprises a turbine inlet conduit 201. The turbine inlet conduit 201 and the exhaust manifold 401 form parts of what is herein referred to as a conduit connection assembly Al, wherein the turbine inlet conduit 201 forms what is herein referred to as a first conduit part, and the exhaust manifold forms what is herein referred to as a second conduit part.

As can be seen in fig. 3, when connected, the turbine inlet conduit 201 and the exhaust manifold 401 form what is herein referred to as a conduit connection delimiting a first fluid conducting volume VI . The turbine inlet conduit 201 and the exhaust manifold 401 present respective connection surfaces 202, 402 adapted to face each other. The connection surfaces are presented by respective flanges 204, 403 of the turbine inlet conduit 201 and the exhaust manifold 401. The turbo charger 2 presents a pressure reducing volume 6 partly formed in the connection surface 202. As discussed more below, the pressure reducing volume 6 is adapted to reduce the mean pressure and the pressure pulses from the first fluid conducting volume VI. Such pressure pulses may be generated by exhaust gas pulses from the cylinders of the engine 1 at openings of exhaust valves and gas exhaustions from the cylinders.

Reference is made also to fig. 4 and fig. 5. The pressure reducing volume 6 is partly formed by a depression 6011 in the connection surface 202 of the turbine inlet conduit 201. The depression 6011 is ring shaped and extends around the first fluid conducting volume VI. In the assembled condition, the connection surface 402 of the exhaust manifold 401 partly delimits the pressure reducing volume 6. Thereby, the depression 6011, and a part of the connection surface 402 of the exhaust manifold 401 form a cavity 601 being ring shaped and extending around the first fluid conducting volume VI . The cavity 601 forms a part of the pressure reducing volume 6.

As can be seen in fig. 4, the turbine inlet conduit 201 and the exhaust manifold 401 form, in their assembled state, a slot 7 providing a communication between the first fluid conducting volume VI and the pressure reducing volume 6. The slot 7 is ring shaped, extends around the first fluid conducting volume VI . The slot 7 also extends in the axial direction of the first fluid conducting volume VI, and is axially offset in relation to the cavity 601.

It should be noted that here the axial direction of the first fluid conducting volume VI is defined by the local direction of the exhaust gas flow in the first fluid conducting volume VI at the conduit connection.

The slot 7 is provided by portions of the connection surfaces 202, 402 of the turbine inlet conduit 201 and the exhaust manifold 401 being offset so that a portion of the exhaust manifold 401 extends into the turbine inlet conduit 201. More specifically, an inner portion of the connection surface 202 of the turbine inlet conduit 201 is axially protruded in relation to an outer portion of the turbine inlet conduit connection surface 202. Also, an outer portion of the connection surface 402 of the exhaust manifold 401 is axially protruded in relation to an inner portion of the exhaust manifold connection surface 402. Thereby, the turbine inlet conduit 201 presents a radially outwardly facing surface portion forming in the assembled condition of the conduit connection assembly one of boundaries of the slot 7, and the exhaust manifold 401 presents a radially inwardly facing surface portion forming in the assembled condition the other boundary of the slot 7. Reference is made also to fig. 6. The length SL of the slot 7, as seen in a cross-section perpendicular to the circumferential direction of the first fluid conducting volume VI, i.e. as seen in fig. 3, fig. 4 and fig. 6, is at least 0.5 mm, preferably at least 1 mm, more preferably at least 2 mm. The width SW of the slot 7, i.e. the extension of the slot in the radial direction of the first fluid conducting volume VI, is 0.001-1 mm, preferably 0.005-0.5 mm, more preferably 0.01-0.1 mm. The slot 7 thus acts by its small relative dimensions as a restriction for the flow from the first fluid conducting volume VI. Preferably, the cavity 601 presents, in a cross-section perpendicular to a circumferential direction, i.e. as seen in fig. 3, fig. 4 and fig. 6, a cross-sectional area which is 100,000 to 1,000,000 times larger than the slot width SW squared.

As can be seen in fig. 4, the turbine inlet conduit 201 and the exhaust manifold 401 form, in their assembled state, a sealing abutment radially outside the depression 6011, i.e. radially outside of the cavity 602. The sealing abutment is formed by a sealing element 8 between the connection surfaces 202, 402 of the turbine inlet conduit 201 and the exhaust manifold 401. The sealing element 8 is provided in the form of a gasket extending around the first fluid conducting volume VI.

As can be seen in fig. 3, the pressure reducing volume 6 presents a draining connection 602. The draining connection 602 is provided in the form of a draining conduit 602 extending from the cavity 601 to a turbine outlet conduit 203 of the turbo charger 2. The turbine outlet conduit 203 forms together with the exhaust conduit 5 a second fluid conducting volume V2. Thus the draining connection 602 is adapted to provide a communication between the first and second fluid conducting volumes VI, V2. Thus, the pressure reducing volume 6 is in this embodiment composed of the cavity 601 and the draining connection 602. Preferably, the pressure reducing volume 6 is 5,000 to 50,000 times larger than the volume occupied by the slot 8. Due to the draining connection 602, the cavity 601 and hence the sealing element 8 will be exposed to substantially the same pressure as that in the second fluid conducting volume V2, which during turbo charger operation is considerably lower than in the first fluid conducting volume VI. This will considerably reduce the wear of the sealing element 8. Also, the high ratio of the volume of the cavity 601 and the volume occupied by the slot 7 will effectively reduce the peak pressures of the pressure pulses in the first fluid conducting volume VI, and thereby avoid sealing element exposure to such peak pressures. In addition, the cavity serves to evacuate to the draining connection 602 the flow entering the volume through the slot 7 and originating from the first fluid conducting volume VI.

Fig. 7 - fig. 11 present a slightly different embodiment of the invention. As understood from fig. 8 and fig. 9, differing from the embodiment described with reference to fig. 3 - fig. 6, the turbine inlet conduit 201 and the exhaust manifold 401 form two first fluid conducting volumes VI. Each first fluid conducting volume VI is adapted to provide a communication to cylinders in a respective set of cylinders of the engine 1. In this example with a six cylinder engine, each set of cylinders consists of three cylinders. The double first fluid conducting volume arrangement provides an advantageous retainment of energy in the exhaust gases and pressure pulses therein for the turbo charger. Also, whereas the connection surfaces 202, 402 are circular in the embodiment described with reference to fig. 3 - fig. 6, in this embodiment, as understood from fig. 8 and fig. 9, the connection surfaces 202 have an approximately rectangular shape. In addition, the depression 6011 of the pressure reducing volume has a rectangular shape with rounded corners. As can be seen in fig. 10 and fig. 11, the draining conduit 602 of the pressure reducing volume is integrated in the body of the turbo charger 2, whereas in the embodiment described with reference to fig. 3 - fig. 6, the draining conduit 602 extends partly separated from the body of the turbo charger 2. Reference is made to fig. 12. A first conduit assembly Al, with a cavity (not shown) of a pressure reducing volume, comprises, similarly to the embodiments described above, a first conduit part in the form of the turbine inlet conduit 201 of the turbo charger 2, and a second conduit part in the form of the exhaust manifold 401. In addition, further conduit connection assemblies are provided at a number of locations in the intake and exhaust systems of the engine.

A second conduit connection assembly A2, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of a compressor outlet 206 of the turbo charger 2 and a second conduit part in the form of the first charged air conduit 302. A third conduit connection assembly A3, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of the first charged air conduit 302 and a second conduit part in the form of the intercooler 303. A fourth conduit connection assembly A4, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of the intercooler 303 and a second conduit part in the form of the second charged air conduit 304. A fifth conduit connection assembly A5, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of the second charged air conduit 304 and a second conduit part in the form of the inlet manifold 301. A sixth conduit connection assembly A6, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of the inlet manifold 301 and a second conduit part in the form of the block 101 of the engine 1. A seventh conduit connection assembly A7, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of the block 101 of the engine 1 and a second conduit part in the form of the exhaust manifold 401. An eighth conduit connection assembly A8, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of an exhaust system unit 502, e.g. in the form of an exhaust valve or an exhaust brake, and a second conduit part in the form of the turbine outlet conduit 203. A ninth conduit connection assembly A9, with a cavity of a pressure reducing volume, comprises a first conduit part in the form of a turbo compound unit 501, connected to the engine crankshaft as is known per se, and a second conduit part in the form of the exhaust system unit 502.

All conduit connection assemblies A1-A9 are provided at locations with relatively high pressures during operation of the turbo charger 2. The second, third, fourth, fifth and sixth conduit connection assemblies A2, A3, A4, A5, A6 share a draining conduit 602 by which they communicate with the air admission conduit 305, which has a relatively low pressure during the turbo charger operation. The first, seventh, eighth and ninth conduit connection assemblies Al, A7, A8, A9 share a draining conduit 602 by which they communicate with the exhaust conduit 5, which has a relatively low pressure during the turbo charger operation. Thus embodiments of the invention can be implemented where there is a pressure drop from the conduit connection to a location downstream of the conduit connection. It should be noted that the conduit connection arrangements A1-A9 may be provided in any suitable

embodiment of the invention, e.g. as described with reference to fig. 3 - fig. 11. It should also be noted that the second, third, fourth, fifth and sixth conduit connection assemblies A2, A3, A4, A5, A6 are all provided on a cool side of the engine 1. Thereby, the sealing abutment formed radially outside of the cavity 602 (see fig. 4) may be formed by the connection surfaces directly contacting each other, i.e. without any sealing element 8. Fig. 13 and 14 shows parts of a connection arrangement according to a further embodiment of the invention. In this embodiment, the pressure reducing volume 6 does not comprise any draining connection 602. Thus, the pressure reducing volume 6 merely comprises a cavity 601 formed by a depression 6011 as described with reference to fig. 3 and fig. 4. Although in such embodiments, the sealing element 8 will experience the same mean pressure as that of the first fluid conducting volume VI, the high ratio of the volume of the cavity 601 and the volume occupied by the slot 7 will effectively reduce the peak pressures of the pressure pulses in the first fluid conducting volume VI, and thereby avoid sealing element exposure to such peak pressures.