DE102018106440A1 - Turbocharger for a vehicle engine - Google Patents

Abstract

A turbocharger for an internal combustion engine comprises a central housing and a bore defined by the central housing. The bore includes a primary annular groove and a secondary annular groove configured to receive a liquid. A slide bearing is disposed within the bore proximate a proximal shaft end so that the slide bearing, along with the rotary shaft, supplies fluids to the primary and secondary annular grooves. The shaft will continue with a turbine wheel and a compressor wheel. The shaft has a longitudinal axis and is supported by the journal bearing for rotation within the bore about the axis. Each of the primary and secondary annular grooves is in fluid communication with a drain.

Description

TECHNICAL AREA

The present disclosure relates generally to turbochargers used in vehicle engines, and more particularly to control of lubrication in the turbocharger housing.

BACKGROUND

Internal combustion engines (ICEs) are often used to generate a significant level of performance over extended periods of time on a reliable basis. Many such ICE units use a supercharger, such as a turbocharger driven by an exhaust gas turbine, which compresses the airflow before entering the intake manifold of the engine to increase engine power and efficiency.

Specifically, a turbocharger is a centrifugal gas compressor that compresses more air and thus more oxygen into the combustion chambers of the ICE than otherwise achievable with normal ambient air pressure. The extra mass of oxygen-containing air that is forced into the ICE improves the volumetric efficiency of the engine by allowing it to burn more fuel in a given cycle, thereby producing more power.

A typical turbocharger employs a central rotor shaft that transmits rotational motion between an exhaust driven turbine wheel and an air compressor wheel. Such a rotor shaft is generally supported within a central housing by thrust and sliding bearings which are lubricated and cooled by engine oil and often additionally cooled by special engine coolant. The exhaust gases that drive the turbine are prevented by piston ring seals from entering the central housing.

Turbochargers generally include a turbine housing for directing exhaust gases from an exhaust gas inlet to an exhaust gas outlet over a turbine wheel. The turbine rotor drives a shaft which is mounted in a central housing part. At the other end of the shaft, a compressor rotor is driven. The compressor rotor is located in a compressor housing, which directs the air from the air filter into the compressor and out to the intercooler. The journal in the central housing is protected by the exhaust gases on the turbine side and the compressed air on the compressor side by piston ring seals.

The crankcase oil is commonly used to lubricate the pivot bearing end faces as well as the pressure surfaces that restrict axial movements of the rotor shaft. Temperatures above 800 ° C can occur in diesel engines in the exhaust gas turbine, and over 1,000 ° C in Otto cycle engines. Heat exiting the turbine housing and turbine wheel into the shaft and central housing raises the temperature to a level that can degrade or "coke" the oil in contact with the rotor shaft and the center housing adjacent the turbine stage. This built-up coked oil can interfere with the bond between the shaft shoulder adjacent to the turbine seal and the center housing. This binding restricts shaft rotation, resulting in poor boost performance of the turbocharger.

As shown, coking is a perennial problem with turbochargers, given the very high operating temperatures. More specifically, heat from the exhaust tends to be conducted along the turbine wheel. The turbine rotor is fixedly connected to the turbocharger shaft and a turbine seal is integrated at the joint between the turbine rotor, the shaft and the central housing. As lubricating oil flows through the tight space between the turbine rotor and the bearings, it is heated to an elevated temperature as the lubricating oil contacts the heated shaft adjacent to the turbine rotor. Accordingly, coking is most likely to occur when the lubricating oil subsequently contacts the shaft which is heated by the turbine housing. Accordingly, a simple, inexpensive and effective means of preventing coking in the center housing of a turbocharger is required.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and thus may include information that does not form the prior art that is already known to a person skilled in the art in this country. Accordingly, there is a need for an improved turbocharger that reduces coking on the turbine shaft adjacent the seal.

SUMMARY

The present disclosure provides a turbocharger for an internal combustion engine. The turbocharger includes a central housing and a bore defined by the central housing. The bore defines a primary annular groove and a secondary annular groove configured to receive a fluid of the rotary shaft. A sliding bearing is arranged in the bore near the proximal end of the shaft. The shaft is further coupled to a turbine wheel at a proximal shaft end and to a compressor wheel at the distal shaft end. The shaft has a longitudinal axis and is rotated by the slide bearing for rotation within the Drilled hole around the axis. The primary and secondary annular grooves are each in fluid communication with a drain.

The present disclosure further provides an internal combustion engine having an engine block with a combustion chamber and a turbocharger. The turbocharger includes a central housing, a bore and a rotating assembly. The rotating assembly includes a shaft having a proximal end with a turbine wheel configured to drive post-combustion gas exiting the combustion chamber. The shaft in the rotating assembly further includes a distal end having a compressor wheel configured to pressurize the airflow for delivery to the combustion chamber. The central housing defines primary and secondary annular grooves configured to receive fluid supplied by the rotary shaft and the sliding bearing. The primary and secondary annular grooves can be located near a proximal shaft end - between the sleeve bearing and a turbine seal. The rotating assembly further includes a shaft having a proximal end with a turbine wheel configured to be driven by post combustion gases from the combustion chamber and a distal end having a compressor wheel to pressurize the air flow for delivery to the combustion chamber.

It will be understood that either in the above-mentioned turbocharger or engine, the sliding bearing includes a first surface defined by an inner diameter, a second surface defined by an outer diameter, and a passage connecting the first and second surfaces. In addition, it will also be understood that a first conduit and a second conduit are also defined in the central housing for either the aforementioned turbocharger or engine, wherein the first conduit may couple the primary annular groove to the drain and the second conduit may couple the secondary annular groove to the drain ,

In another embodiment of the present disclosure, the primary annular groove defines a first radius and the secondary annular groove defines a second radius; the second radius may be greater than the first radius.

The present disclosure and its particular characteristics and advantages will become more apparent from the following detailed description with reference to the accompanying drawings.

list of figures

• 1 zeigt einen Fahrzeugmotor mit einem Turbolader in Übereinstimmung mit verschiedenen Ausführungsformen der vorliegenden Offenbarung.
• 2 veranschaulicht eine schematische Querschnittsdarstellung eines Turboladers gemäß einer oder mehrerer Ausführungsformen der vorliegenden Offenbarung.
• 3 zeigt eine vergrößerte Querschnittdarstellung des Zentralgehäuses.
• 4 veranschaulicht eine Seitenansicht eines zweiten, nicht einschränkenden, exemplarischen Gleitlagers in Übereinstimmung mit verschiedenen Ausführungsformen der vorliegenden Offenbarung.

These and other features and advantages of the present disclosure will become apparent from the following detailed description, best mode, claims, and accompanying drawings.

• 1 FIG. 12 shows a vehicle engine with a turbocharger in accordance with various embodiments of the present disclosure. FIG.
• 2 12 illustrates a schematic cross-sectional view of a turbocharger in accordance with one or more embodiments of the present disclosure.
• 3 shows an enlarged cross-sectional view of the central housing.
• 4 FIG. 12 illustrates a side view of a second, non-limiting, exemplary journal bearing in accordance with various embodiments of the present disclosure. FIG.

Like reference numerals refer to like parts in the description of the several views of the drawings.

DETAILED DESCRIPTION

Reference will now be made in detail to presently preferred compositions, embodiments, and methods of the present disclosure which illustrate the best modes of carrying out the present disclosure which are presently known to the inventors. The figures are not necessarily to scale. It should be understood, however, that the disclosed embodiments are merely exemplary of the present disclosure, which may be embodied in various and alternative forms. Therefore, the specific details disclosed herein are not to be construed as limitations, but merely as a representative basis for any aspects of the present disclosure and / or serve as a representative basis only for teaching the various applications to those skilled in the art.

Except in the examples, or where expressly stated, all numerical references to quantities of material or conditions of reaction and / or use in this specification are to be understood to be modified by the term "about" so as to describe the broadest scope of the present disclosure. Execution within the specified numerical limits is generally preferred. Further, unless expressly stated otherwise: Percent, "parts of" and ratio values by length; When a group or class of materials is described as being suitable or preferred for a particular purpose in the context of the present disclosure, this means that mixtures of two or more members of the group or class are equally suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation, and applies mutatis mutandis to normal grammatical variations of the abbreviation initially defined. And, unless expressly stated otherwise, the measurement of a property is measured by the same technique as stated before or after for the same property.

It is further understood that the present disclosure is not limited to the particular embodiments and methods described below, as certain components and / or conditions may, of course, vary. Furthermore, the terminology used herein is for the purpose of describing various embodiments of the present disclosure only and is not intended to be limiting in any way.

It should also be understood that, as used in the specification and the appended claims, the singular forms "a" and "the" include plural referents unless the context clearly indicates otherwise , For example, the reference to a singular component is intended to encompass a variety of components.

The term "comprising" is synonymous with "including," "having," "containing," or "characterized by." These terms are to be construed as inclusive and open and do not exclude additional unnamed elements or process steps.

The term "consisting of" excludes any element, step or component not specified in the claim. If this term appears in a section of the body of a claim, rather than immediately following the introduction, it limits only the element described in the section, excluding other elements from the claim as a whole.

The term "consisting essentially of" limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel features of the claimed subject matter.

The terms "comprising", "consisting of" and "consisting essentially of" may alternatively be used. Where one of these three terms is used, the subject matter disclosed and claimed herein may involve the use of one of the other two terms.

Disclosures of the publications referred to in this application are incorporated by reference in their entirety into this application to more particularly describe the state of the art to which this present disclosure pertains.

The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application or uses of the present disclosure. In addition, there is no obligation to be bound by any of the theories presented in the preceding background or the following detailed description.

With reference to 1 , becomes an internal combustion engine 10 in accordance with various embodiments of the present disclosure. The motor 10 also includes an engine or cylinder block 12 with a plurality of cylinders arranged therein 14 , As shown, the engine includes 10 also a cylinder head 16 , To every cylinder 14 heard a piston 18 who moves back and forth in it. In the cylinders 14 form between the bottom surface of the cylinder head 16 and the tips of the pistons 18 combustion chambers 20 , As one skilled in the art knows, the combustors are 20 designed to receive a fuel / air mixture for subsequent combustion therein.

As shown, the engine includes 10 also a crankshaft 22 that is configured to be inside the cylinder block 12 rotates. As is known to a person skilled in the art, the crankshaft 22 from the pistons 18 as a result of combustion of the fuel / air mixture at a suitable ratio in the combustion chambers 20 set in rotation. After the fuel / air mixture in a special combustion chamber 20 burned, serves the alternating movement of a particular piston 18 also for removing the combustion gases 24 from the respective cylinder 14 , The motor 10 also includes a liquid pump 26 , The liquid pump 26 is configured for pressurized fluid or engine oil 28 to different bearings, like the crankshaft 22 , to deliver. The liquid pump 26 can be either mechanically directly by the engine 10 or over an electric motor (not shown) are driven.

The motor 10 additionally includes an induction system 30 , which is configured to provide a pressurized airflow 31 from the environment to the cylinders 14 to channel. The induction system 30 includes an intake air line 32 , a turbocharger 34 and an intake manifold 36 , Although not shown, the induction system can 30 in addition an air filter upstream of the turbocharger 34 for removing foreign particles and other airborne debris from the airflow 31 include. The intake air line 32 is designed the airflow 31 from the environment to the turbocharger 34 while the turbocharger is pressurizing the received airflow and directing the pressurized airflow to the intake manifold 36 is designed. The intake manifold 36 in turn distributes the previously pressurized airflow 31 to the cylinders 14 for mixing with a corresponding amount of fuel and subsequent combustion of the resulting fuel-air mixture. Although the present disclosure is directed to the internal combustion engine 10 Focused on a hub configuration, other engine designs, such as a rotary engine with combustion chambers, also become more concentrated 20 , but not considered with reciprocating.

With reference to 2 includes the turbocharger 34 a rotating assembly 38 , The rotating assembly 38 includes a wave 40 which is usually made of steel and as the first proximal end 40A (Turbine end) is defined, as well as a distal second end 40B (Compressor end). At the wave 40 is a turbine wheel 46 proximal to the first end 40A mounted and for rotation with the shaft 40 on a longitudinal axis 42 the shaft configured by post combustion gases 24 coming from the cylinders 14 escape. The turbine wheel 46 located inside a turbine housing 44 that is a turbine screw or snail 50 contains. The turbine screw 50 receives the afterburning gases 24 and directs the exhaust gases to the turbine wheel 46 , The turbine screw 50 is also to achieve specific performance data, such as efficiency and response time of the turbocharger 34 , configured.

As shown, the rotary turbine 46 mounted on the same shaft as the compressor. Therefore, the compressor rotates with the turbine 46 , The exhaust leaves the vehicle, wasting less energy than usual. Accordingly, the rotation of the turbine should 46 , the wave 40 and the compressor are not obstructed to provide the optimum performance.

With reference to 2 a schematic cross-sectional view of the turbocharger is shown. The turbocharger includes a turbocharger housing assembly 52 , consisting of a compressor housing 60 , Central housing 54 and a turbine housing 44 , The turbocharger housing assembly 52 includes a central portion (central housing 54 ), which is a pair of spaced sliding bearings and rotating therein an elongated shaft 40 receives. A turbine wheel 46 will come to an end 40A the wave 40 connected or integrally molded - the turbine end 40A the wave 40 , At the opposite end 40B the wave 40 - the distal end 40B the wave 40 - becomes a compressor wheel 58 worn and can by one on the shaft 40 bolted nut to be secured.

A turbine housing 44 can with the central housing 54 be integrated and define an exhaust inlet leading to a radially outer portion of the turbine wheel 46 to lead. The turbine housing 44 also defines an exhaust outlet 68 , the turbine wheel 46 is derived. Similarly defines a compressor housing 60 an air inlet 72 that is to the compressor wheel 58 and an air outlet (not shown) leading from a diffuser chamber 77 opens.

When the engine shuts off exhaust to the inlet, both the heat energy source and the source of cooling oil flow to the turbocharger stop working. However, both the turbine housing 44 as well as the turbine wheel 46 hot and store a significant amount of residual heat. This residual heat is supplied to the cooler parts of the turbocharger as the heat, which was forwarded during its operation. However, neither cooling oil flow nor internal compressor air flow prevails now. Thus, the temperature of the shaft increases 40 and the central housing 54 increasingly for a time beyond their normal operating temperatures. This temperature increase, unless controlled, can lead to increased temperatures at the shaft 40 , on the turbine housing 44 , as well as at the lubricating oil outlet 92 to lead. Increased temperatures in these areas could degrade or coke the residual oil here - especially at the turbine seal 100 that are at the groove 102 at the junction of the turbine 46 , the wave 40 and the central housing 54 can be located. In addition, the relatively low mass and the low heat storage capacity of the turbine wheel 46 small additional factors that further contribute to the coking problem on the shaft 40 contribute. The degradation of the turbine seal 100 is particularly problematic because this is a rotational resistance of the shaft 40 trigger and can lead to failure of the turbocharger. Accordingly, it is understood that heat transfer within the turbocharger is different from the turbine wheel 46 with the wave 40 above a conductive path can occur between the materials.

As in 2 shown, oil enters the turbocharger via the oil inlet 64 and at least one sliding bearing 56 for the turbocharger shaft 40 forwarded. While a plain bearing 56 can be used, it is understood that several plain bearings 56 even for a single wave 40 can be used. The plain bearing 56 The present disclosure may be considered a fully floating bearing 56 be configured so that the liquid that is supplied to this, a first liquid film between the bore and the sliding bearing 56 and a second liquid film between the sliding bearing 56 and the wave 40 can form. With reference to 4 can the plain bearing 56 Also, a first surface defined by an inner diameter, a second surface defined by an outer diameter may be defined with a passage connecting first and second surfaces. It is further understood that multiple channels in the plain bearing 56 can be defined that connect the first and second surfaces.

With reference to 3 is the primary ring groove 82 configured for about 90% of the rotational movement of the shaft 40 and / or the sliding bearing 56 radially outward spun oil absorb. Order now oil from this primary ring groove 82 Dismount defines the central housing 54 a first line 88 from there down to the drain 92 opens. The process route 92 further includes an oil outlet 66 so that the oil from the turbocharger 34 can be led out. The central housing 54 further defines a first shoulder 120 , a second annular groove 84 and a second line 90 , The first shoulder 120 is also configured to the primary ring groove 82 from the secondary ring groove 84 to separate and distinguish. The secondary ring groove 84 is also in fluid communication with the drain 92 over a second line 90 ,

While the first shoulder 120 the primary ring groove 82 probably from the secondary ring groove 84 separates and differentiates, is the first shoulder 120 Primarily configured to remove most of the oil from the shaft 40 in the first line 88 to lead. If, however, residual oil over the primary ring groove 82 flows out, receives the second annular groove 84 the remaining about 10% of the rotational movement of the shaft 40 thrown off oil and passes the oil to the second line 90 , so any residual oil to the drain 92 can flow.

Again with reference to 2 and 3 For example, the vehicle engine and the turbocharger include a central housing 54 , one from the central housing 54 defined bore, a plain bearing 56 and a rotating assembly 38 , The bore can be from the central housing 54 be defined and has a primary annular groove 82 and a secondary annular groove 84 , which is configured to hold a liquid. The plain bearing 56 can be located within the bore. The rotating assembly 38 includes the wave 40 with a turbine wheel 46 and a compressor wheel 58 , The turbine wheel 46 can be configured for propulsion by post combustion gases while the compressor wheel 58 can be configured to apply pressure to the air flow for passage into the combustion chamber.

The wave 40 may include a longitudinal axis, wherein the shaft 40 from the sliding bearing 56 can be supported for rotation within the bore about the longitudinal axis. The primary and secondary annular grooves 82 . 84 can be configured to liquid from the rotary shaft 40 and / or the sliding bearing 56 to recieve. When touching the surface of the primary ring groove 82 and the secondary annular groove 84 , the liquid can enter the drain 92 flow. As mentioned earlier, the primary ring groove 82 in communication with the process route 92 over the first line 88 stand while the secondary annular groove 84 in fluent communication with the process route 92 over the second line 90 can stand. However, it should be understood that a single common conduit may be used for both the first and second annular grooves.

It is understood that the shaft 40 a close end 40A proximal to the turbine wheel 46 and a distal end 40B near the compressor wheel 58 includes. It is further understood that the primary and secondary annular grooves 82 . 84 in the housing near the proximal end 40A the wave 40 are defined. The primary and secondary annular grooves 82 . 84 can, but need not, in the housing between the plain bearing 56 and the turbine wheel 46 To be defined. As in 3 shown, the plain bearing 56 as a full or half-floating camp 56 be configured so that the liquid that is supplied to this, a first liquid film between the bore and the sliding bearing 56 and a second liquid film between the sliding bearing 56 and the wave 40 can form. With further reference to 4 can the plain bearing 56 also a first by an inner diameter 78 defined surface 72 , a second by an outside diameter 80 defined surface 74 with a passage 76 be defined, the first and second surfaces 72 . 74 combines. It is understood that several lines 76 in the plain bearing 56 can be defined to the first and second surfaces 72 . 74 connect to. The plain bearings 56 may, but need not, be a brass bush.

Referring again to 3 , become the primary and secondary annular grooves 82 . 84 shown enlarged. As shown, the primary annular groove 82 a first radius 94 define while the secondary annular groove 84 a second radius 96 can define. The second radius 96 may, but need not, be greater than the first radius 94 , However, it goes without saying that the second radius 96 and the first radius 94 Alternatively, by and large, the same or the second radius 96 smaller than the first radius 94 can not, but does not have to be. It is understood that the primary and secondary annular grooves 82 . 84 machined and / or in the central housing 54 can be poured.

The present disclosure also provides a turbocharger that has a central housing 54 , one through the central housing 54 defined bore, a plain bearing 56 and a rotating assembly 38 includes. The bore can still have a primary annular groove 82 and a secondary annular groove 84 include, for receiving a liquid of the rotary shaft 40 and / or the sliding bearing 56 are configured. The plain bearing 56 can be arranged inside the hole that the primary ring groove 82 at least a portion of the proximal end 40A the wave 40 surrounds, while the secondary annular groove 84 a shaft section 48 the turbine 46 surrounds. It is understood that the primary and secondary annular grooves 82 . 84 in the central housing 54 the area between the sliding bearing 56 and the turbine seal 100 be formed as in 3 shown.

The rotating assembly 38 continues to contain a wave 40 with a turbine wheel 46 configured for driving by combustion gases from the combustion chamber, as well as a compressor wheel 58 configured to pressurize the airflow for delivery to the combustion chamber. The wave 40 has a longitudinal axis and is through the sliding bearing 56 supported for rotation within the bore about the longitudinal axis. Similar to the aforementioned embodiment, a plurality of plain bearings 56 to get integrated. However, that feeds the turbine 46 nearest plain bearing 56 Liquid, together with the rotary shaft 40 to the primary annular groove 82 ,

The wave 40 may include a longitudinal axis, wherein the shaft 40 from the sliding bearing 56 can be supported for rotation within the bore about the longitudinal axis. The primary and secondary annular grooves 82 . 84 can be configured to liquid from the rotary shaft 40 and / or the sliding bearing 56 to receive over centrifugal force. If oil 28 along the rotary shaft 40 in the direction of the primary ring groove 82 flows, much of the excess oil 28 from wave 40 and plain bearings 56 centrifugal force is thrown off into the primary annular groove. The excess oil then runs over the first line 88 into the drainage route 92 from. As far as additional excess oil at the proximal end 40A the wave 40 and at the turbine shaft 48 remains and as well as this excess oil 28 continue towards the turbine seal 100 flows, this oil becomes 28 from the rotary shaft via centrifugal force from the turbine shaft 48 in the secondary ring groove 84 spun off. The oil 28 is subsequently via a secondary line 90 to the run-off 92 forwarded. It is understood that a single common line instead of the first and second lines 88 . 90 from both grooves 82 . 84 can be used.

Accordingly, the slide bearing feed 56 and / or the rotary shaft 40 the liquid to the primary ring groove 82 while the shaft section 48 the turbine 46 (which is part of the rotating shaft 40 forms) residual fluid from the shaft 40 to the secondary ring groove 84 , When touching the surface of the primary ring groove 82 and the secondary annular groove 84 , the liquid (oil 28 ) into the drainage route 92 flow. As mentioned, the primary ring groove 82 in communication with the process route 92 over the first line 88 stand while the secondary annular groove 84 in fluent communication with the process route 92 over the second line 90 can stand.

Similar to the earlier embodiment of the described vehicle engine, the shaft includes 40 of the turbocharger a proximal end 40A near the turbine wheel 46 and a distal end 40B near the compressor wheel 58 , It is further understood that the primary and secondary annular grooves 82 . 84 in the central housing 54 near the proximal end 40A the wave 40 are defined. The primary and secondary annular grooves 82 . 84 can, but need not, in the central housing 54 between the plain bearing 56 and the turbine wheel 46 To be defined. As in 2 and 3 shown, the plain bearing 56 as a full or half-floating camp 56 be configured so that the liquid that is supplied to this, a first liquid film 110 between the bore and the plain bearing 56 and a second liquid film 112 between the plain bearing 56 and the wave 40 can form. Referring again to 3 , become the primary and secondary annular grooves 82 . 84 shown enlarged. As shown, the primary annular groove 82 a first radius 94 define while the secondary annular groove 84 a second radius 96 can define. The second radius 96 may, but need not, be greater than the first radius 94 , However, it goes without saying that the second radius 96 and the first radius 94 Alternatively, by and large, the same or the second radius 96 smaller than the first radius 94 can not, but does not have to be. It is understood that the primary and secondary annular grooves 82 . 84 machined and / or in the central housing 54 can be poured.

Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that there are a large number of variants. It is further understood that the exemplary embodiment or exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description provides those skilled in the art with a convenient plan for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.

Claims (10)

A turbocharger for an internal combustion engine having a combustion chamber, the turbocharger comprising: a central housing; a bore defined by the central housing having a primary annular groove and a secondary annular groove adapted to receive a fluid; a slide bearing disposed in the bore such that the primary annular groove surrounds the slide bearing and conveys the fluid thereto; and a rotating assembly having a shaft with a turbine wheel configured to be driven by post combustion gases emitted from the combustion chamber and having a compressor wheel configured to pressurize the air flow for delivery to the combustion chamber; the shaft includes a longitudinal axis and is held by the sliding bearing for rotation about the longitudinal axis in the bore. The turbocharger according to Claim 1 wherein the shaft has a proximal end and a distal end. The turbocharger according to Claim 2 wherein the central housing defines the primary and secondary annular grooves near the proximal end of the shaft. The turbocharger according to Claim 3 wherein the sliding bearing is configured as a fully floating bearing so that the fluid conveyed therefor forms a first fluid film between the bore and the sliding bearing and a second fluid film between the sliding bearing and the shaft. The turbocharger according to Claim 4 and further wherein the sliding bearing includes a first surface defined by an inner diameter, a second surface defined by an outer diameter, and a passage connecting the first and second surfaces. The turbocharger according to Claim 5 wherein the primary and secondary annular grooves are in fluid communication with a drain line. The turbocharger according to Claim 6 , further comprising a first conduit and a second conduit, the first conduit coupling the primary annular groove to the drainage passage and the second conduit coupling the secondary annular groove to the drainage passage. The turbocharger according to Claim 7 wherein the primary annular groove defines a first radius and the secondary annular groove defines a second radius, the second radius being greater than the first radius. The turbocharger according to Claim 8 , wherein the sliding bearing is a brass bushing. The turbocharger according to Claim 9 wherein the drain is in communication with an oil outlet.

Images