Supercharged internal combustion engine with an integrated coupling flange for a turbosupercharger

Abstract

 A supercharged internal combustion engine (100,100') comprising a motor unit (101,101') and at least one hydraulic circuit;
- a turbocharger assembly (105,105') comprising and a central body (122) having at least one hydraulic channel (136,137,137A,142,143) connected via flanges to a hydraulic circuit of the motor unit (101,101').

Description

Field of the invention

[0001] The present invention refers to a supercharged internal combustion engine comprising:

• a motor unit including a cylinder block, a head, an exhaust manifold and at least one hydraulic circuit,
• a turbocharger assembly fluid dynamically connected to said exhaust manifold, the turbocharger assembly comprising a turbine, a compressor and a central body interposed therebetween, wherein the central body comprises at least one hydraulic channel.

General technical problem

[0002] Supercharging the internal combustion engines by means of a turbocharger, that has recently acquired great importance due to the new design trends consolidated in the field of the automotive engineering, implies, in view of several indisputable advantages, several technical drawbacks which require to be addressed and resolved.

[0003] Such drawbacks comprise, among others:

• the mechanical connection of the turbocharger assembly to the motor unit of the internal combustion engine,
• the lubrication of the turbocharger assembly, and
• the cooling of the turbocharger assembly.

[0004] The first two drawbacks are common to spark ignition engines and to compression ignition engines, while the problems related to the cooling of the turbocharger assembly are typical of spark ignition engines due to the higher temperatures reached by the exhaust gases with respect to compression ignition engines.

[0005] Referring to figure 1, an internal combustion engine 1 of the known type comprises a motor unit 1A, in turn including a cylinder block 2 (schematically illustrated), a head 3 and an exhaust manifold 4, and a turbocharger assembly 5.

[0006] The turbocharger assembly 5 comprises a centripetal turbine 6, a centrifugal compressor 7 and a central body 8 interposed between the turbine 6 and the compressor 7.

[0007] The turbine 6 comprises a body 9, a flange 10 integral with said body 9 (sometimes indicated as "turbine body") and positioned in correspondence of an inlet port of the exhaust gases, a flange 11 for connection to a discharge line of the engine 1 and a control valve 12 controlled by a pneumatic actuator 13. An impeller, not shown in the figures, is arranged inside the body 9.

[0008] The compressor 7 comprises a body 14 (sometimes indicated as "compressor body"), an inlet port 15 and an outlet port 16. An impeller, not shown in the figures, is arranged inside the compressor 14. The impellers of the turbine 6 and of the compressor 7 are supported by a shaft rotatably supported within the central body 8 by means of bearings. The impellers and the shaft are coaxial to each other and rotatably connected.

[0009] The central body 8 comprises at least one hydraulic channel provided internally therein and in communication with the outside by means of one or more inlet/outlet ports for a fluid.

[0010] The turbine body 9, the compressor body 14 and the central body 7 define a stator assembly (i.e. an assembly of fixed parts) of the turbocharger assembly 5, while the impellers of the turbine 6 and of the compressor 7, together with the shaft which connects them rotatably and the bearings, define a rotor assembly (i.e. an assembly of rotating parts) of the turbocharger assembly 5.

[0011] Particularly referring to figures 1, 2, illustrating a turbocharger assembly for application on spark ignition engines, the central body 8 comprises an inlet port 17 for cooling water hydraulically connected, by means of a first channel provided inside the central body 8 (not visible in figures 1, 2), to an outlet port 18 onto which a fitting 19 connected to a pipe 20 hydraulically connected to the cooling circuit of the motor unit 1A of the internal combustion engine 1 is fitted.

[0012] The central body 8 further comprises an inlet port 21 for lubrication oil onto which a fitting 22 in turn connected to a piping 23 connected to the lubrication circuit of the motor unit 1A of the internal combustion engine 1 is fitted. The inlet port 21 is hydraulically connected by means of a channel not visible in figures 1, 2 to a flanged outlet port 24 onto which a piping 25 which returns the oil towards the cylinder block of the motor unit 1A is fitted. The channel which connects the ports 21 and 24 develops around the shaft which supports the impellers for the lubrication of the bearings thereof.

[0013] The solution illustrated herein by way of example is typical of spark ignition internal combustion engines wherein, due to the high temperatures of the exhaust gases entering into the turbine 6, in combination to the channel which connects the ports 21, 24 in which the oil circulates for the lubrication of the bearings of the shaft of the turbocharger assembly 5, they also require the presence of a cooling circuit of the central body 8 comprising the ports 17, 18 and the channel which joins them. This, evidently, with the aim of lowering the temperatures of the hot side of the turbocharger assembly 5, comprising the turbine 6 and the central body 8.

[0014] Compression ignition internal combustion engines generally do not require, alongside the oil channel inside the central body 8, the presence of a channel containing cooling water due to the lower temperatures of the exhaust gases.

[0015] The exhaust manifold 4 is connected to the head 3 by means of threaded joints 26 and comprises a plurality of conduits associated to each of the cylinders of the internal combustion engine 1 which come together in terminal section 27 terminating in a flange 28 shaped substantially identically to the flange 10 on the turbocharger assembly 5.

[0016] The coupling between the turbocharger assembly 5 and the motor unit 1A of the internal combustion engine 1 is provided by means of direct coupling, with the interposition of a gasket, between the flanges 10, 28 which are fastened to each other by means of fastening elements 29 traversing holes arranged in homologous positions on the flanges 10, 29.

[0017] The coupling between the motor unit 1A and the turbocharger assembly 5 described above reveal several drawbacks. First and foremost, in order to resist to the high temperatures of the exhaust gases of spark ignition engines, the body 9 of the turbine 6 made of nickel steels (in particular Nimonic® steels) which are quite expensive.

[0018] The cost of such steels increases proportionally to the nickel content, the higher the temperatures the turbine 6 has to sustain, the higher the nickel content. The flange 10 has considerable dimensions if compared to those of the body 9 and thus represents a significant part of the total production cost of the turbocharger assembly 5.

[0019] Furthermore, the presence of piping for water and oil flowing into the turbocharger assembly 5 has a considerable impact on the overall costs of the turbocharger assembly 5 and of the entire internal combustion engine 1 given that this implies using fittings, gaskets, threaded joints which have a considerable influence on the costs of the turbocharger assembly 5. This problem is particularly felt both in the case of turbochargers for applications on spark ignition engines and for application on compression ignition engines.

Object of the invention

[0020] The object of the present invention is that of overcoming the previously described technical problems. In particular, the object of the present invention is that of providing a turbocharged internal combustion engine in which the impact of the cost of the turbocharger assembly is considerably lower with respect to the prior art solutions.

Summary of the invention

[0021] The object of the present invention is attained by an internal combustion engine having the characteristics forming the subject of the claims that follow, which form integral part of the technical disclosure provided herein in relation to the invention.

[0022] In particular, the object of the present invention is attained by an internal combustion engine having all the characteristics listed at the beginning of the present description and further characterised in that said motor unit comprises a first connection flange including at least one terminal port hydraulically connected to said at least one hydraulic circuit and in that the turbocharger assembly comprises a second connection flange provided on the central body wherein the second connection flange comprises at least one terminal port hydraulically connected to said at least one hydraulic channel of the central body and also wherein the first and the second connection flange are arranged for the mutual coupling, wherein the mutual coupling hydraulically connects at least one terminal port of the first connection flange ad at least one terminal port corresponding of said second connection flange and mechanically connects the turbocharger assembly to the motor unit of the internal combustion engine.

Brief description of the drawings

[0023] Now, the invention will be described with reference to the attached drawings, purely provided by way of non-limiting example, wherein:

• figure 1, previously described, is a perspective view of a turbocharged internal combustion engine of the known type and with some components removed for the sake of clarity,
• figure 2 is a view according to arrow II of figure 1,
• figure 3 is a partly exploded view of the internal combustion engine of figure 1,
• figure 4 is a perspective view of an internal combustion engine according to the present invention with some components removed for the sake of clarity,
• figure 5 is a view according to arrow V of a component of the internal combustion engine of figure 4,
• figure 6 is a view according to arrow VI of a turbocharger assembly of the internal combustion engine of figure 4,
• figure 7 is a sectional view along line VII-VII of figure 4,
• figure 8 is a sectional view according to line VIII-VIII of figure 4,
• figure 9 is a view according to arrow IX of figure 4,
• figure 10 is a schematic view of a variant of the internal combustion engine according to the invention, partly sectioned and with some components removed for the sake of clarity, and
• figure 11 is an enlarged view of a detail indicated with XI in figure 10

Detailed description of the invention

[0024] An internal combustion engine according to the present invention is indicated with 100 in figure 4. The combustion engine 100 comprises a motor unit 101, in turn including a cylinder block 102, a head 103 and an exhaust manifold 104 integrally cast in the head 103, and a turbocharger assembly 105. Referring to figures 4, 5, 7, the exhaust manifold 104 comprises a junction 106 towards which exhaust conduits 107 (figure 5) fluid dynamically connected to single cylinders of the engine 100 converge.

[0025] The fitting 106 is integral with a terminal 108 which defines a common outlet of the exhaust gases. The terminal 108 comprises, therein, a front gas-tight surface 109 (figure 5).

[0026] The head 103 comprises, integrally cast therewith and with the exhaust manifold 104, a first connection flange 110 integral therewith and having a front coupling surface 111. The first connection flange 110 comprises a pair of threaded holes 112 arranged at end positions thereof and open on the coupling surface 111 and also comprises a first terminal port 113 open on the surface 111 and in hydraulic communication, by means of a channel 114, with a lubrication circuit of the motor unit 101 inside which the lubricating oil flows.

[0027] Furthermore, in this embodiment the coupling flange 110 comprises a second and a third terminal port 115, 116 also open on the surface 111 and hydraulically connected, by means of respective channels 117, 118, to a cooling circuit of the motor unit 101, particularly to a cooling jacket 119. In the illustrated embodiment, the jacket 119 is part of the head 103 and it is preferably divided into several overlapped layers.

[0028] Referring to figure 6, the turbocharger assembly 105 comprises a centripetal turbine 120, a centrifugal compressor 121 and a central body 122.

[0029] The turbine 120 comprises a body 123 (at times indicated, in the present description, as "turbine body") including an inlet port 124 and an outlet port 125 and comprises a control valve 126 actuated by means of a pneumatic actuator 127.

[0030] An impeller, not visible in figure 6, is rotatably mounted in the turbine 120. The centrifugal compressor 129 comprises a volute body 128 (at times indicated, in the present description, as "compressor body") including an intake port 129 and a delivery port 130. An impeller, not visible in figure 6, supported by a shaft which traverses the central body 122 and which rotatably connects it to the impeller of the turbine 120 is located inside the body 128.

[0031] The central body 122 comprises, at its interior, bearings supporting the shaft which connects the turbine and the compressor impellers and a hydraulic channel 131 (figure 7) suitable to contain lubricating oil for the lubrication of the bearings which support the shaft.

[0032] Analogously to the turbocharger assembly 5, the turbine body 123, the compressor body 128 and the central body 122 define a stator assembly of the turbocharger assembly 105, while the impellers, the shaft which connects them rotatably and the bearings which support it define a rotor assembly of the turbocharger assembly 105.

[0033] The central body 122 further comprises a second coupling flange 132 having a front coupling surface 133 preferably shaped substantially identically to the surface 111 and comprising, in homologous positions with respect to the first coupling flange 110, the following elements:

• a pair of through holes 134 in homologous positions and coaxial with respect to the threaded holes 112,
• a fourth terminal port 135 open on the surface 132 hydraulically connected, by means of channels 136, 137, 137A (figure 7) to an outlet port 138 onto which a pipe 139 in hydraulic communication with the cylinder block of the motor unit 101 is flanged, wherein the port 135 is in homologous position and coaxial to the port 113,
• a fifth and a sixth port 140, 141 in homologous positions and coaxial with respect to the ports, respectively 115, 116 and in hydraulic communication therebetween by means of respective channels 142, 143 hydraulically communicating with respect to each other.

[0034] The coupling between the turbocharger assembly 105 and the motor unit 101 is provided as follows.

[0035] Referring to figure 7, the first and the second connection flange 110, 132 are mutually coupled directly by nearing the front coupling surfaces 111, 133, preferably with the interposition of a gasket. The mutual coupling of the flanges 110, 132 is tightened by means of screws 144 which traverse the holes 134 and are engaged in the threaded holes 112, mechanically fixing the turbocharger assembly 105 to the motor unit 101, particularly to the exhaust manifold 104.

[0036] The mutual coupling of the flanges 110, 132 provides a hydraulic connection between the first terminal port 113 and the fourth terminal port 135, between the second terminal port 115 and the fifth terminal port 140 and between the third terminal port 116 and the sixth terminal port 141.

[0037] In such a manner, a direct hydraulic connection of the channels 136, 137 to the lubrication circuit of the motor unit 101 and of the channels 142, 143 to the cooling circuit of the motor unit 101, particularly to the jacket 119, is provided.

[0038] The turbocharger assembly 105 is fluid dynamically connected to the exhaust manifold 104 by means of insertion of the inlet port 124 into the terminal 108 without employing further connection elements. This allows providing a bell-and-spigot joint between the port 124 and the terminal 108 wherein the port 124 is inserted into the terminal 108 maintaining a clearance C (figure 8) between them and the front surface 109 into which a gas-tight gasket is inserted.

[0039] The internal combustion engine 100 operates as follows.

[0040] The exhaust gases produced by the combustion within the engine 100, particularly within the motor unit 101, are collected by the manifold 104 and exit therefrom through the terminal 108. From here, they are conveyed directly to the turbine 120 by means of the inlet port 124 maintaining the impeller of the turbine itself in rotation and thus also rotating the shaft and the impeller of the compressor 121. It should be observed that, contrary to the engines of the known type, the structural connection function of the turbocharger assembly to the motor unit is carried out by the connection flanges 110, 132 and no longer by a flange on the turbine 120. The bell-and-spigot joint with a clearance C between the inlet port 124 and the terminal 108, with gasket interposed, also allows adapting to the thermal expansions during the operation, given that the turbocharger assembly 105 is subjected to a non uniform temperature field, with extreme values on the side of the turbine 120.

[0041] The connection flanges 110, 132 also carry out the functions which on the turbocharged engines of the known type are assigned to the piping and fittings which are connected to the ports provided on the central body. In particular, during the operation of the engine 100, the lubricating oil circulating within the lubrication circuit of the motor unit 101, flows into the turbocharger assembly 105 through the channel 114 and channels 136, 137, thus lubricating the bearings for supporting the shaft of the turbocharger assembly 105. Then, the oil returns to the lubrication circuit of the motor unit 101, in particular towards the cylinder block 102 or towards an oil sump of the engine 100, by means of the outlet port 138 and the piping 139.

[0042] Simultaneously, the cooling water circulating within the cooling circuit of the motor unit 101 passes from the jacket 119 to the channel 117 and therefrom it flows into the channel 142, from which it reaches, after cooling the central body 122, to the channel 143, to the channel 118 and once again to the jacket 119 and to the cooling circuit of the motor unit 101.

[0043] It is thus clear that the connection flanges 110, 132 not only serve the function of structural connection between the turbocharger assembly 105 and the motor unit 101, but they also incorporate all the hydraulic connections required for the lubrication of the moveable parts of the turbocharger assembly and the cooling of the central body of the same.

[0044] This allows eliminating the flange 10 described previously and saving material when constructing the turbine, with the ensuing apparent advantages in terms of costs. Nevertheless, it is possible to eliminate all the pipings which - in the internal combustion engines of the known type - convey oil and cooling water to the central body of the turbocharger assembly, thus saving on the costs related to pipings, fittings and the elements for connecting the ports of the central body typical of the turbocharged internal combustion engines of the known type.

[0045] In the case where the internal combustion engine 100 is of the compression ignition type, due to the lower temperatures of the exhaust gases flowing into the turbine 120, the first and the second connection flange 110, 132 would be without ports 115, 116 of the corresponding channels 117, 118 as well as without ports 140, 141 and the corresponding channels 142, 143, given that the cooling of the central body 122 would not be required. In such a manner, the coupling flange 110 would comprise a sole terminal port, i.e. the port 113 in hydraulic connection with the lubrication circuit of the motor unit 101. Also the second connection flange would comprise a sole terminal port, i.e. the terminal port 135 arranged in homologous position and coaxial with respect to the terminal port 113 on the first connection flange and in hydraulic connection therewith due to the mutual coupling of the connection flanges 110, 132. Through the terminal port 113 the lubricating oil circulating within the abovementioned motor unit would flow into the central body 122 through the terminal port 135 and the channels 136, 137.

[0046] Also in this case, there would be a considerable impact on costs, given that the pipings, the fittings and the respective gaskets typical of turbocharged engines of the known type in which the abovementioned elements are fitted into the central body of the turbocharger assembly, would be eliminated. Nevertheless, even this solution allows saving material regarding the turbine, even though the margin is less marked with respect to the spark ignition engines mainly due to the fact that the material is less precious.

[0047] Referring to figure 10, number 100' indicates an advantageous variant of an internal combustion engine according to the invention. Components identical to those described previously are indicated using the same reference number.

[0048] The internal combustion engine 100' comprises a motor unit 101', in turn including a cylinder block 102', a head 103' and an exhaust manifold 104' fastened by means of threaded joints to the head 103, and a turbocharger assembly 105'.

[0049] The components of the turbocharger assembly 105' are identical to those of the turbocharger assembly 105 but the relative angular position between the central body 122 and the turbine and the compressor 120, 121 is different.

[0050] The exhaust manifold 104' comprises a terminal 108' inside which the inlet port 124 of the turbine 120 is inserted providing a bell-and-spigot joint. The second flange 132' is coupled, in a manner entirely analogous with the previous description, with a connection flange 110' substantially identical to the connection flange 110, which is made integral with the cylinder block 102'. In the case where the engine 100' is of the compression ignition type, the channels 117, 118 and the corresponding terminal ports 115, 116 just like the channels 142, 143 and the corresponding terminal ports 140, 141 are not provided due to the reasons described previously.

[0051] The operation of the internal combustion engine 100' remains entirely unvaried with respect to what has been described regarding the internal combustion engine 100, given that the coupling between the flanges 110', 132' provides the same functions with respect to the coupling between the flanges 110, 132.

[0052] However, a separate exhaust manifold 104, of the conventional type, though without a connection flange to the turbine 120 like in the engines of the known type, is used in this case. This allows obtaining the advantages of the present invention even without using heads with the exhaust manifold integrated.

[0053] Naturally, the details and embodiments may vary, even significantly, with respect to what has been described and illustrated purely by way of example, without departing from the scope of the present invention as defined by the attached claims.

Claims

1. A supercharged internal combustion engine (100, 100') comprising:

- a motor unit (101, 101') including a cylinder block (102, 102') a head (103, 103'), an exhaust manifold (104, 104') and at least one hydraulic circuit;

- a turbocharger assembly (105, 105') fluid dynamically connected to said exhaust manifold (104, 104'), said turbocharger assembly (105, 105') comprising a turbine (120), a compressor (121) and a central body (122) interposed therebetween, wherein said central body (122) comprises at least one hydraulic channel (136, 137, 137A, 142, 143)
said internal combustion engine (100, 100'), being characterized in that said motor unit comprises a first connection flange (110, 110') including at least one terminal port (113, 115, 116) hydraulically connected to said at least one hydraulic circuit and in that said turbocharger assembly (105, 105') comprises a second connection flange (132, 132') provided on said central body (122) wherein said second connection flange (132, 132') comprises at least one terminal port (135, 140, 141) hydraulically connected to said at least one hydraulic channel (136, 137, 137A 142, 143) of said central body (122) and wherein the first and the second connection flange (110, 132; 110', 132') are arranged for the mutual coupling, wherein said mutual coupling hydraulically connects said at least one terminal port (113, 115, 116) of said first connection flange (110, 110') to a corresponding terminal port (135, 140, 141) of said second connection flange (132, 132') and mechanically connects said turbocharger assembly (105, 105') to said motor unit (101, 101') of said internal combustion engine (100, 100').

2. The internal combustion engine (100, 100') according to Claim 1, characterized in that said exhaust manifold (104, 104') comprises a terminal (108, 108') inside of which an inlet port (124) of said turbine (120) is inserted.

3. The internal combustion engine (100, 100') according to Claim 1, characterized in that said first connection flange (110, 110') comprises a first (113), a second (115) and a third (116) terminal port, wherein said first terminal port is hydraulically connected, by means of a channel (114), to a lubrication circuit of said motor unit (101, 101') of said internal combustion engine (100, 100') and said second and third terminal port are hydraulically connected (116, 117) to a cooling circuit of said motor unit (101, 101') of said internal combustion engine (100, 100').

4. The internal combustion engine according to Claim 3, characterized in that:

- said second connection flange (132, 132') comprises a fourth (135), a fifth (140) and a sixth (141) terminal port, wherein said fourth terminal port (135) is hydraulically connected (136, 137, 137A) to an outlet port (138), and

- said fifth and sixth terminal port (140, 141) are hydraulically connected to respective channels (142, 143) communicating with each other,
wherein said forth (135), fifth (140) and sixth (141) terminal ports are located, on said second connection flange (132, 132'), in homologous positions with respect to said first (113), second (115) and third (116) terminal port respectively on said first connection flange (110, 110').

5. The internal combustion engine (100, 100') according to Claim 4, characterized in that:

- said first terminal port (113) of said first connection flange (110, 110') is hydraulically connected to said fourth terminal port (135) of said second connection flange (132, 132'),

- said second (115) and third (116) terminal port of said first connection flange (110, 110') are hydraulically connected, respectively, to said second (115) and third (116) terminal port of said second connection flange (132, 132').

6. The internal combustion engine (100, 100') according to Claim 1, characterised in that said first connection flange (110, 110') comprises a pair of threaded holes (112) and in that said second connection flange (132, 132') comprises a pair of through holes (134) wherein said threaded holes (112) are located on said first connection flange (110, 110') in homologous position with respect to said through holes (134) of said second connection flange (132, 132').

7. The internal combustion engine (100, 100') according to Claim 6, characterized in that the mutual coupling between said first (110, 110') and second connection flanges (132, 132') is tightened by means of fastening elements (144) traversing said through holes (134) and engaging within said threaded holes (112).

8. The internal combustion engine (100, 100') according to Claim 1, characterized in that said first connection flange (110, 110') comprises a sole terminal port (113) in hydraulic communication with a lubrication circuit of said motor unit (101, 101') of said internal combustion engine (100, 100').

9. The internal combustion engine according to Claim 8, characterized in that said second connection flange (132, 132') comprises a sole terminal port (135) hydraulically connected to an outlet port (138), wherein said sole terminal port (135) of said second connection flange (132, 132') is in homologous position with respect to said sole terminal port (113) of said first connection flange (110, 110').

10. The internal combustion engine according to Claim 9, characterized in that said sole terminal port (113) of said first connection flange (110, 110') is hydraulically connected to said sole terminal port (135) of said second connection flange (132, 132').

11. The internal combustion engine (100) according to Claim 1, characterized in that said exhaust manifold (104) is integrally cast in said head (103) and said first connection flange (110) is integral with said head (103).

12. The internal combustion engine (100') according to Claim 1, characterized in that said first connection flange is made integral with said cylinder block (102').

13. The internal combustion engine (100') according to Claim 12, characterized in that said exhaust manifold (104) is fastened to said head (103).

14. The internal combustion engine (100) according to Claim 2, characterized in that said terminal (108) comprises a front surface (109), wherein said inlet port (124) of said turbine (120) is inserted in said terminal (108) with a clearance (C) with respect to said front surface (109) and with an interposed gas-tight gasket.

15. The internal combustion engine (100, 100') according to Claim 4 or 9, characterized in that said outlet port (138) is hydraulically connected to a piping (139) arranged for returning oil towards the cylinder block (102, 102') or an oil sump of said motor unit (101, 101') of said internal combustion engine (100, 100').

Drawing