TURBOCHARGER COMPRESSOR

Abstract

Turbocharger (119) for use with an internal combustion engine (100), comprising the following: a housing (122) for a turbine (120) that surrounds a rotatable wheel of the turbine (120) which is connected to a shaft (126); a central housing comprising a bearing arrangement rotatably supporting the shaft (126), the shaft (126) extending through the central housing; a compressor housing (217) surrounding one end of the shaft (126); and a compressor wheel (213) which is connected to the end of the shaft (126) and rotatably arranged within the compressor housing (217), the compressor wheel (213) comprising: a central hub (302) with a center line, a foot section and an end section, wherein the foot section is adjacent to a connection interface between the central hub (302) and the shaft (126); a plurality of blades (308) formed around the central hub (302), wherein the plurality of blades (308) comprises a group of complete blades (310) extending from the foot section of the central hub (302) to a maximum distance from the foot section along the centerline, the maximum distance being adjacent to the end section of the central hub (302); wherein the multitude of shovels (308) further comprises a group of half-shovels (312), wherein the half-shovels (312) extend from the foot section of the hub to an area along the centerline which is between 55% and 70% of the maximum distance along the centerline; wherein the plurality of blades (308) are grouped in repeating sets of blades arranged around the compressor wheel (213), each repeating set comprising at least one complete blade (310) and at least one half blade (312); wherein each complete shovel (310) has a first leading edge (318) which is arranged near the end section and wherein the leading edge (318) is inclined backwards towards the foot section; wherein the leading edge (318) of each complete blade extends at an acute angle α with respect to the center line and wherein the angle α is approximately 9.5 degrees; wherein each complete blade (310) forms a first tip (320) at a radially outer end of the respective first leading edge (318), wherein the first tips (320) of the complete blades (310) are axially aligned relative to the center line and are arranged at a first distance X1 with respect to a foot diameter (322) of the central hub (302), and wherein the first distance is the maximum distance; wherein each of the half-shovels (312) comprises a second leading half-shovel edge (324) forming a second tip (326), the second tips (326) being axially aligned relative to the centerline and arranged at a second distance X2 with respect to the foot diameter (322) of the central hub (302); and wherein the multitude of shovels (308) further comprises a group of partial shovels (314), extending from the foot section of the central hub (302) to a partial blade area along the centerline which is between 40% and 55% of the maximum distance along the centerline, each partial blade (314) comprising a leading partial blade edge (328) and a tip (330), wherein the tips (330) of the partial blades (314) are axially aligned relative to the center line and arranged at a third distance with respect to the foot diameter (322) of the central hub (302); wherein, when the compressor wheel (213) rotates during operation, at a specific radial orientation relative to the base section of the compressor wheel (213), a partial blade (314) passing in the specific radial orientation is followed by a half blade (312) and then a full blade (310), wherein the full blade (310) has a leading edge (318) of the full blade, the half blade (312) has a leading half-blade edge (324), and the partial blade (314) has a leading partial blade edge (328), and wherein, When the compressor wheel (213) rotates during operation, at a specific radial orientation relative to the rotation of the compressor wheel (213), a leading edge (318) of a complete blade passes by in the specific radial orientation, followed by a leading partial blade edge (328) and then a leading half-blade edge (324).

Description

TECHNICAL AREA

[0001] This patent disclosure relates generally to turbochargers for use with internal combustion engines and in particular to impellers for centrifugal compressors used as part of turbochargers for use with internal combustion engines. BACKGROUND

[0002] Internal combustion engines are supplied with a mixture of air and fuel for combustion within the engine, which generates mechanical power. To maximize the power generated by the combustion process, the engine is often equipped with an air intake system with turbocharging.

[0003] A turbocharged air intake system includes a turbocharger that uses exhaust gas from the engine to compress the air flowing into the engine, forcing more air into the engine's combustion chamber than the engine could otherwise draw in. This increased air supply allows for a higher fuel delivery, resulting in increased engine power output.

[0004] The efficiency of an engine's fuel-to-energy conversion can depend on many factors, including the efficiency of the engine's turbocharger. Turbocharger efficiency can be influenced by the turbine components that extract energy from the exhaust gas, as well as the compressor components that use that extracted energy to compress air supplied to the engine cylinders.

[0005] In the past, various attempts have been made to improve the efficiency of turbochargers, partly by improving the operational efficiency of the compressor through adjustments to the design features of the compressor impeller. An example of a compressor impeller can be found in DE102009007843A1, which includes a compressor impeller with a set of split blades arranged between two successive undivided blades. As shown in DE 10 2009 007 843 A1, for example, in Fig. 1 and Fig. 2. The compressor wheel comprises a longer blade and a shorter blade between full-length blades, in that order and relative to a direction of rotation of the compressor wheel (from right to left, as shown in Fig. 2 shown). However, the compressor wheel arrangements described in DE 10 2009 007 843 A1 can only partially achieve considerable efficiency improvements for certain compressor frame sizes, and only for certain compressor wheel sizes, and may be unsuitable for large displacement engines that require large quantities of air flowing through the compressor while maintaining acceptable performance at the lower end of operating conditions.

[0006] US patent 2011 / 0173975A1 discloses a turbocharger comprising a compressor with a compressor wheel, wherein the compressor wheel has a full vane and a splitter vane, and a housing comprising a drain channel, an injection channel and a recirculation channel.

[0007] JP 2009 - 228 549 A discloses a centrifugal compressor with a blade arrangement having three different blade types of different lengths.

[0008] CN 2 04 140 486 U discloses a turbocharger with a compressor wheel whose blades are arranged in groups of decreasing length and height, and a diffuser with closed channels corresponding to the blades.

[0009] The purpose of this application is the development of an improved turbocharger for internal combustion engines. In particular, the efficiency of the turbocharger compressor is to be increased. This is achieved through a special design of the compressor wheel with blades of varying lengths, as described. SUMMARY

[0010] According to one aspect of the revelation, a turbocharger for use in an internal combustion engine is described. The turbocharger comprises a turbine housing surrounding a rotatable turbine wheel connected to a shaft, a central housing containing a bearing arrangement rotatably supporting the shaft, the shaft extending through the central housing, a compressor housing surrounding one end of the shaft, and a compressor wheel connected to the end of the shaft and rotatably arranged within the compressor housing.

[0011] The compressor wheel comprises a central hub with a centerline, a root section, and a tail section. The root section is located adjacent to a connection interface between the central hub and a shaft. A plurality of blades is formed around the central hub. This plurality of blades includes a group of full blades extending from the root section of the central hub to a maximum distance along the centerline. This maximum distance is located adjacent to the tail section of the central hub. The plurality of blades further includes a group of half-blades extending from the root section of the hub to a region along the centerline that is between 55% and 70% of the maximum distance along the centerline.The multitude of blades is grouped into repeating sets of blades arranged around the wheel, with each repeating set comprising at least one full blade and at least one half blade. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a block diagram of an internal combustion engine according to the disclosure. Fig. Figure 2 is a perspective view of a turbocharger arrangement in accordance with the disclosure. Fig. 3 is a sectional view of the Fig. 2 turbocharger arrangement shown. Fig. 4 and Fig. Figure 5 illustrates perspective views of a compressor wheel in accordance with the revelation from the front or side. Fig. Figure 6 is a partial section through a compressor impeller in accordance with the disclosure. Fig. 7 and Fig. Figure 8 are diagrams of the pressure ratio or efficiency for a compressor in accordance with the disclosure. DETAILED DESCRIPTION

[0012] This disclosure relates to an improved turbocharger configuration for use with an internal combustion engine. In particular, the disclosure relates to an improved compressor in which a compressor wheel, which may also be referred to as a compressor impeller or compressor wheel, is of a centrifugal compressor type in which blades of different lengths are arranged to increase compressor efficiency and reduce the transient response times of the compressor, thereby increasing engine power.

[0013] A simplified example block diagram of a 100 motor is in Fig. Figure 1 shows the engine 100 comprising a cylinder housing 104 surrounding a plurality of combustion cylinders 104. In the illustrated embodiment, six combustion cylinders are shown in an inline or "I" configuration, but any other number of cylinders arranged in a different configuration, such as a "V" configuration, can be used. The plurality of combustion cylinders 106 are fluidically connected to an exhaust port 108 via exhaust valves (not shown). The exhaust port 108 is connected to a turbine 120 of a turbocharger 119. In the illustrated embodiment, the turbine 120 comprises a housing 122 with a gas inlet 124, which is fluidly connected to the exhaust port 108 and arranged to receive exhaust gas from it. Exhaust gas supplied to the turbine 120 causes a turbine wheel (not shown) connected to a shaft 126 to rotate.Exhaust gas leaves the housing 122 of the turbine 120 through an outlet 128. The exhaust gas at the outlet 128 is optionally routed through other exhaust aftertreatment components and systems, such as an aftertreatment device 130, which mechanically and chemically removes combustion by-products from the exhaust gas stream, and / or a silencer 132, which dampens engine noise, before it is released to the environment through a vent or exhaust 134.

[0014] The rotation of shaft 126 causes a compressor wheel (not shown) of a compressor 136 to rotate. As shown, the compressor 136 is a radial compressor designed to receive a stream of filtered fresh air from an air filter 138 through a compressor inlet 140. Pressurized air at an outlet 142 of the compressor 136 is directed via a charge air duct 144 to an intercooler 146 before being supplied to an intake manifold 148 of the engine 100. In the illustrated embodiment, air is directed from the intake manifold 148 to the combustion cylinders 106, where it is mixed with fuel and burned to generate engine power.

[0015] An optional EGR system 102 includes an optional EGR cooler 150, which is fluidically connected to an EGR gas supply port 152 of the exhaust duct 108. A stream of exhaust gas from the exhaust duct 108 can pass through the EGR cooler 150, where it is cooled, before being fed via an EGR duct 156 to an EGR valve 154. The EGR valve 154 can be electronically controlled and configured to meter or control the flow rate of the gas passing through the EGR duct 156. An outlet of the EGR valve 154 is fluidly connected to the intake manifold 148, so that exhaust gas from the EGR channel 156 can mix with compressed air from the charge air cooler 146 within the intake manifold 148 of the engine 100.

[0016] The exhaust gas pressure at the exhaust duct 108, commonly referred to as stagnation pressure, is higher than the ambient pressure, partly due to the flow restriction formed by the turbine 120. The pressure of the air or air / EGR gas mixture in the inlet manifold 148, commonly referred to as boost pressure, is higher than the ambient pressure due to the compression provided by the compressor 136. The pressure difference between the stagnation pressure and the boost pressure, together with the flow restriction and the flow cross-section of the components of the EGR system 102, largely determines the maximum EGR gas flow rate that can be achieved under various engine operating conditions.

[0017] An outline drawing of the turbocharger 119 is in Fig. 2 is shown, and a cross-sectional view through the compressor is in Fig. Figure 3 illustrates this. For the sake of simplicity, structures and features that are identical or similar to those already described can be designated by the same reference numerals in the following description, with reference to these figures. As shown, the shaft 126 is connected at one end to a compressor wheel 213. The compressor wheel 213 is arranged to rotate within a compressor housing 217.

[0018] The compressor 136 comprises a compressor blade bearing ring 274, on which blades 276 are arranged radially around the compressor wheel 213. The blades 276 establish a fluid connection between a compressor inlet bore 278, which contains the compressor wheel 213, and a compressor screw passage 280, which is formed in the compressor housing 217 and terminates in a compressor outlet opening 282. Screws 284 and circular plate segments 286 connect the compressor housing 217 to a compressor mounting plate 268.

[0019] An outline view of the compressor rotor or compressor wheel 213 is shown in a frontal perspective in Fig. 4 shown, and in a side perspective in Fig. 5. A partial sectional view of the compressor wheel 213 is shown in Fig. Figure 6 shows that, with reference to these figures, the compressor wheel 213 comprises a central hub 302 with a free end 304 and a connecting end 306, at which the compressor wheel 213 can be integrated into the shaft 126 ( Fig. 3) In the illustrated embodiment, the central hub 302 has a generally circular cross-section, the diameter of which is as shown in Fig. 6 shown along a hub centerline 307 non-linearly decreased in one direction from the connecting end 306 to the free end 304 of the central hub 302.

[0020] Various blades 308 are formed around and along the central hub 302. The blades 308 serve to redirect air entering the compressor towards the compressor outlet while also compressing the air. In the illustrated embodiment, three different types of blades 308 are shown formed on the compressor wheel 213. In particular, the compressor wheel 213 comprises a first plurality of blades 310, a second plurality of blades 312, and a third plurality of blades 314. Each blade in the first, second, and third plurality of blades 310, 312, and 314 serves to redirect air towards the compressor outlet and / or to divide airflows passing over and around the compressor wheel to increase compressor efficiency.

[0021] In particular, each of the first plurality of buckets 310 is a full-size bucket compared to the remaining buckets 308, meaning that the full-size bucket extends from a foot region 316 of the central hub 302 to a region adjacent to the free end 304, as shown in Fig. Figure 5 shows that each of the first plurality of blades 310 comprises a leading edge 318 located near the free end 304 and inclined backward at an acute angle α of approximately 9.5 degrees with respect to the hub centerline 307. Each leading edge 318 forms a tip 320. The tips 320 are arranged at a first distance X1 from a foot diameter 322 of the central hub 302, as shown in Figure 5. Fig. Figure 5 shows the first set of blades 310 in the compressor wheel 213 comprising six blades, as shown in Fig. 4 and Fig. 5 illustrates.

[0022] Each of the second set of blades 312, which can be called half-blades, is shorter than a full-size blade, meaning that each of the second set of blades 312 extends from the foot region 316 of the central hub 302 to a region closer to the foot diameter 322 than the leading edges 318 of the first set of blades 310. Each of the second set of blades 312 includes a leading edge 324 forming a tip 326 located at a second distance X2 from the foot diameter 322 of the central hub 302, as shown in Fig. 5 shown. The second set of blades 312 in the compressor wheel 213 comprises six blades, as shown in Fig. 4 and Fig. 5 illustrates.

[0023] Similar to the second plurality of blades 312, each of the third plurality of blades 314, which can be described as a partial blade, is shorter than a full-size blade, meaning that each of the third plurality of blades 314 extends from the foot region 316 of the central hub 302 to a region closer to the foot diameter 322 than the leading edges 318 of the first plurality of blades 310 and also closer than the leading edges 324 of the second plurality of blades 312. Each of the third plurality of blades 314 includes a leading edge 328 forming a tip 330 located at a third distance X3 from the foot diameter 322 of the central hub 302, as shown in Fig. 5 shown. The third set of blades 314 in the compressor wheel 213 comprises six blades, as shown in Fig. 4 and Fig. 5 illustrates.

[0024] As in Fig. As can be seen in Figure 5, the first, second and third plurality of blades 310, 312 and 314 are each arranged in sets, such that each set comprises one blade from each of the plurality of blades, for a total of 18 blades in the illustrated embodiment; however, other arrangements with different numbers of sets of 3 blades each can also be used, for example less or more than 6, 9, 12, 15, 21, 24, etc., depending on the size of the compressor wheel and other design considerations.

[0025] Furthermore, different ratios of the lengths X1, X2, and X3 can be used. In the illustrated embodiment, X1 is selected such that it is approximately 1.6 times X2 and approximately 2.2 times X3. In other words, for the illustrated embodiment, X2 is approximately 0.62 * X1, or 62% of X1, but it can be any value between 55% and 70% of X1. Similarly, for the illustrated embodiment, X3 is approximately 0.46 * X1, or 46% of X1, but it can be any value between 40% and 55% of X1. Based on these ratios, it should be clear that X2 is approximately 1.36 * X3, or X3 is approximately 0.73 * X2, or approximately 73% of X2, but it can be any value between 65% and 80%.

[0026] At the base of the wheel, the blades are arranged such that, in a direction of rotation R, as indicated in the figure, a blade from the first plurality of blades 310 is followed by a blade from the second plurality of blades 312, and then these two are followed by a blade from the third plurality of blades 314, at each radial position of the compressor wheel 213 as the compressor wheel 213 rotates. Near the free end 304, however, the blades are arranged differently, such that the leading edge 328 of a blade from the third plurality of blades 314 follows the leading edge 318 of a blade from the first plurality of blades 310, and then the leading edge 324 of a blade from the second plurality of blades 312 follows.

[0027] These arrangements are in Fig. 4 and Fig. 5 shown. With reference to Fig. Figure 5, where the direction of rotation R is also indicated, shows that when the compressor wheel 213 rotates from the top of the figure towards the bottom, for the visible blades, a blade A of the first plurality of blades 310 follows a blade B of the second plurality of blades 312, and the two blades A and B follow a blade C of the third plurality of blades 314. Thus, the order of the blades during rotation, with respect to the base of the blades, can be described as C - B - A as the compressor wheel 213 rotates. With respect to the leading edges, in Fig. 4. To see that the leading edge of blade A is followed by the leading edge of blade C, and then by the leading edge of blade B. Thus, the order of the blades with respect to their leading edges during rotation near the free end can be expressed as A - C - B. The differences in the order in which the various blade features meet the incoming air (which hits the wheel in the Fig. The orientation shown in section 4 is met and is located in the area shown in the Fig. (in the orientation shown, from left to right), it has been advantageously and unexpectedly shown that the compressor efficiency is considerably increased. Each blade 308 further comprises a side edge 332, which is designed to generally conform to a profile of the inner profile of the compressor casing 217 ( Fig. 3) follows, with a predetermined margin that can be minimized to improve the operational efficiency of the compressor. INDUSTRIAL APPLICABILITY

[0028] The present disclosure relates to a radial turbocharger compressor for internal combustion engines, but can also be applied to other types of compressors with rotating blades. In the embodiments shown herein, it has been found that a compressor with a compressor wheel or impeller having three separate sets of blades of different lengths and shapes unexpectedly increases the compressor and turbocharger efficiency, for example, with respect to the pressure ratio across the compressor and with respect to temperature tropic efficiency.

[0029] A qualitative diagram showing two pressure ratio characteristic curves for a comparison compressor and a compressor with a single compressor wheel in accordance with the present disclosure is presented in Fig. Figure 7 illustrates this. Generally, the pressure ratio for a compressor is defined as the ratio of the absolute fluid pressure at the compressor outlet to the absolute fluid pressure at the compressor inlet. In the graph of Fig. Figure 7 shows the pressure ratio for both the comparison and the improved compressor in accordance with the disclosure along the vertical axis 402, and a corrected fluid flow through the compressor as a percentage of a maximum flow is plotted along the horizontal axis 404. The graph shows two sets of curves representing operating points, with a comparison curve 406, representing a comparison compressor, shown in solid lines, and an improved curve 408, representing the compressor in accordance with the disclosure, shown in dashed lines. As can be seen from the graph in Fig. As can be seen in Figure 7, the improved compressor performance shown by curves 408 can achieve a consistently higher pressure ratio of between 5% and 15% compared to the reference compressor shown by curves 406.

[0030] A qualitative diagram showing the compressor efficiency for a reference compressor and the compressor with a compressor wheel in accordance with the present disclosure is presented in Fig. 8 shown.

[0031] In general, compressor efficiency can be viewed as the ratio of the work output of an ideal isentropic compression process to the work input required to develop a specific pressure ratio across the compressor inlet and outlet. In the graph of Fig. Figure 8 represents the compressor efficiencies, expressed as a percentage of a maximum selected energy efficiency, for example 85%, for the reference and improved compressors, plotted along the vertical axis 410 in accordance with the disclosure, and a corrected fluid flow through the compressor, as a percentage of a maximum flow, is plotted along the horizontal axis 412. The graph shows two groups of curves representing operating points, with one group of reference curves 414 representing the different efficiency curves for the reference compressor with respect to the corrected mass flow and shown in solid lines.

[0032] The second group of curves 416, shown in dashed lines, represents the performance curves in relation to the corrected mass flow rate of the compressor in accordance with the disclosure. As shown in the graph in Fig.As shown in Figure 8, the peak efficiency of the reference compressor begins to decline from approximately 95% of the selected efficiency baseline to approximately 85% above a corrected mass flow rate of about 55%, at a corrected flow rate of approximately 80% of the maximum flow rate. In contrast, the peak efficiency of the improved compressor is maintained at approximately 80% above 95% of the selected reference efficiency by a corrected mass flow rate of approximately 80%, and falls to approximately 90% of the selected efficiency above 90% of the maximum flow rate.

[0033] It is understood that the foregoing description provides only examples of the disclosed system or technology. However, it is acknowledged that other implementations of the disclosure may differ in detail from the examples given above. All references to the disclosure or its examples are to be understood as references to the specific example discussed here. Any formulations of distinction or devaluation with respect to certain features are intended to indicate a lesser preference for these features, but not to exclude them from the scope of the disclosure unless otherwise stated.

Claims

[1] Turbocharger (119) for use with an internal combustion engine (100), comprising the following: a housing (122) for a turbine (120) that surrounds a rotatable wheel of the turbine (120) which is connected to a shaft (126); a central housing comprising a bearing arrangement rotatably supporting the shaft (126), the shaft (126) extending through the central housing; a compressor housing (217) surrounding one end of the shaft (126); and a compressor wheel (213) which is connected to the end of the shaft (126) and rotatably arranged within the compressor housing (217), the compressor wheel (213) comprising: a central hub (302) with a center line, a foot section and an end section, wherein the foot section is adjacent to a connection interface between the central hub (302) and the shaft (126); a plurality of blades (308) formed around the central hub (302), wherein the plurality of blades (308) comprises a group of complete blades (310) extending from the foot section of the central hub (302) to a maximum distance from the foot section along the centerline, the maximum distance being adjacent to the end section of the central hub (302); wherein the multitude of shovels (308) further comprises a group of half-shovels (312), wherein the half-shovels (312) extend from the foot section of the hub to an area along the centerline which is between 55% and 70% of the maximum distance along the centerline; wherein the plurality of blades (308) are grouped in repeating sets of blades arranged around the compressor wheel (213), each repeating set comprising at least one complete blade (310) and at least one half blade (312); wherein each complete shovel (310) has a first leading edge (318) which is arranged near the end section and wherein the leading edge (318) is inclined backwards towards the foot section; wherein the leading edge (318) of each complete blade extends at an acute angle α with respect to the center line and wherein the angle α is approximately 9.5 degrees; wherein each complete blade (310) forms a first tip (320) at a radially outer end of the respective first leading edge (318), wherein the first tips (320) of the complete blades (310) are axially aligned relative to the center line and are arranged at a first distance X1 with respect to a foot diameter (322) of the central hub (302), and wherein the first distance is the maximum distance; wherein each of the half-shovels (312) comprises a second leading half-shovel edge (324) forming a second tip (326), the second tips (326) being axially aligned relative to the centerline and arranged at a second distance X2 with respect to the foot diameter (322) of the central hub (302); and wherein the multitude of shovels (308) further comprises a group of partial shovels (314), extending from the foot section of the central hub (302) to a partial blade area along the centerline which is between 40% and 55% of the maximum distance along the centerline, each partial blade (314) comprising a leading partial blade edge (328) and a tip (330), wherein the tips (330) of the partial blades (314) are axially aligned relative to the center line and arranged at a third distance with respect to the foot diameter (322) of the central hub (302); wherein, when the compressor wheel (213) rotates during operation, at a specific radial orientation relative to the base section of the compressor wheel (213), a partial blade (314) passing in the specific radial orientation is followed by a half blade (312) and then a full blade (310), wherein the full blade (310) has a leading edge (318) of the full blade, the half blade (312) has a leading half-blade edge (324), and the partial blade (314) has a leading partial blade edge (328), and wherein, When the compressor wheel (213) rotates during operation, at a specific radial orientation relative to the rotation of the compressor wheel (213), a leading edge (318) of a complete blade passes by in the specific radial orientation, followed by a leading partial blade edge (328) and then a leading half-blade edge (324). [2] Turbocharger (119) according to claim 1, wherein the central hub (302) has a generally circular cross-section with a varying diameter, wherein the diameter does not decrease linearly in one direction from the foot end to the end section. [3] Turbocharger (119) according to claim 1, wherein each complete blade (310) and each half blade (312) serves to redirect air radially outwards with respect to the center line and around the foot section when the compressor wheel (213) is in operation inside the compressor housing (217). [4] Turbocharger (119) according to claim 3, wherein each half-blade (312) serves to divide an airflow which moves along and is driven by an adjacent full blade (310).

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