WO2015105761A1

WO2015105761A1 - Compressor stage inlet passive oil collector

Info

Publication number: WO2015105761A1
Application number: PCT/US2015/010226
Authority: WO
Inventors: Shannon SCOTT
Original assignee: Borgwarner Inc.
Priority date: 2014-01-07
Filing date: 2015-01-06
Publication date: 2015-07-16
Also published as: DE112015000249T5; DE112015000249B4

Abstract

A passive oil collector (50) is disposed in the compressor stage air inlet (32) of an exhaust gas turbocharger (10). The collector includes a conical portion (66) that is enlarged relative to the air intake pipe (7) that delivers a mixture of clean air from the air intake filter and oil-rich air from the crankcase vent (6). When the air-oil mixture enters the conical portion from the air intake pipe, it expands and loses velocity. As the air-oil mixture slows, the relatively heavy suspended oil falls out of suspension and settles to the lower-velocity perimeter of the conical portion, while the lighter air continues into the compressor air inlet.

Description

COMPRESSOR STAGE INLET PASSIVE OIL COLLECTOR

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and all the benefits of U.S. Provisional Application

No. 61/924,257, filed on January 7, 2014, and entitled "Compressor Stage Inlet Passive Oil Collector," which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a turbocharger with an improved compressor and more particularly, to a compressor inlet duct including a passive oil collector.

BACKGROUND OF THE INVENTION

Engine crankcase emissions are a result of gas escaping past piston rings into the crankcase due to high cylinder pressures. In the engine crankcase, the gases are contaminated with oil mist, fuel, water, and other by-products of engine operation. The contaminated emissions may escape from the engine breather into the engine compartment and engine intake system. To reduce environmental impact and engine compartment fouling, some vehicles employ closed crankcase ventilation, in which crankcase gases are vented to an air intake of a turbocharger.

Turbochargers are provided on an engine to deliver air to the engine intake at a greater density than would be possible in a normal aspirated configuration. This allows more fuel to be combusted, thus boosting the engine's horsepower without significantly increasing engine weight. An exhaust gas turbocharger includes a turbine section including a turbine wheel, a compressor section including a compressor wheel, and a bearing section disposed between the turbine section and compressor section. The bearing section supports a shaft that connects the turbine wheel to the compressor wheel. In use, the exhaust flow from the engine exhaust manifold enters the turbine section at a turbine inlet to drive the turbine wheel. As such, the turbine wheel provides rotational power to drive the compressor wheel and thereby drives the compressor of the turbocharger. Compressed air generated by the compressor wheel is then provided to the engine intake as described above.

During turbocharger operation, filtered air is drawn into a compressor air inlet which defines a passage extending axially to the compressor wheel. Rotation of the compressor wheel forces pressurized air flow radially outwardly from the compressor wheel into a compressor volute for subsequent pressurization and flow to the engine. When closed crankcase ventilation is employed, a vent line delivers engine crankcase emissions to a compressor air intake pipe at a location upstream of the compressor air inlet.

SUMMARY

In some aspects, a passive oil collector includes an inlet opening, an outlet opening, and a longitudinal axis that extends between the inlet opening and the outlet opening. The passive oil collector also includes a conical portion disposed between the inlet opening and the outlet opening. The conical portion has a first end, a second end opposed to the first end, and a radial dimension that decreases along the longitudinal axis from a maximum at the first end, which is disposed adjacent to the inlet opening, to a minimum at the second end, which is disposed adjacent to the outlet opening. The maximum radial dimension of the conical portion is greater than the radial dimension of the inlet opening.

The passive oil collector may include one or more of the following features: The radial dimension of the inlet opening is the same as the radial dimension of the outlet opening. The conical portion second end defines the outlet opening, and the conical portion first end is axially spaced apart from the inlet opening. The passive oil collector further includes an intake tube that extends through the inlet opening, wherein a terminal end of the intake tube lies in a plane that is transverse to the longitudinal axis and passes through the conical portion first end. The passive oil collector further includes a cylindrical collecting portion extending axially from the conical portion first end, the collection portion including a drain outlet. The passive oil collector further includes an intake tube that extends through the inlet opening, and the collecting portion surrounds a circumference of a portion of the intake tube. A ratio of the conical portion first end radial dimension to the inlet opening radial dimension is in a range 1.5 to 4.0. The passive oil collector further includes a baffle disposed between the conical portion first end and conical portion second end. The baffle is a solid disc. The passive oil collector further includes a cooling jacket that surrounds the conical portion.

In some aspects, an exhaust gas turbocharger includes a turbine section including a turbine wheel and a compressor section. The compressor section includes a compressor housing defining a compressor air inlet, and a compressor wheel disposed within the compressor housing adjacent to the compressor air inlet. The compressor wheel is connected to the turbine wheel via a shaft. The turbocharger also includes a passive oil collector disposed at the compressor air inlet. The passive oil collector includes an inlet opening, an outlet opening, and a longitudinal axis that extends between the inlet opening and the outlet opening. The passive oil collector also includes a conical portion disposed between the inlet opening and the outlet opening. The conical portion has a first end, a second end opposed to the first end, and a radial dimension that decreases along the longitudinal axis from a maximum at the first end, which is disposed adjacent to the inlet opening, to a minimum at the second end, which is disposed adjacent to the outlet opening. The maximum radial dimension of the conical portion is greater than the radial dimension of the inlet opening.

The turbocharge may include one or more of the following features: The radial dimension of the inlet opening is the same as the radial dimension of the outlet opening. The conical portion second end defines the outlet opening, and the conical portion first end is axially spaced apart from the inlet opening. The passive oil collector further includes an intake tube that extends through the inlet opening, wherein a terminal end of the intake tube lies in a plane that is transverse to the longitudinal axis and passes through the conical portion first end. The passive oil collector further includes a cylindrical collecting portion extending axially from the conical portion first end, the collection portion including a drain outlet. The passive oil collector further includes an intake tube that extends through the inlet opening, and the collecting portion surrounds a circumference of a portion of the intake tube. A ratio of the conical portion first end radial dimension to the inlet opening radial dimension is in a range 1.5 to 4.0. The passive oil collector further includes a baffle disposed between the conical portion first end and conical portion second end. The baffle is a solid disc. The passive oil collector further includes a cooling jacket that surrounds the conical portion.

In some aspects, a passive oil collector is provided in the compressor stage air inlet. The passive oil collector includes a conical portion that is enlarged relative to the air intake pipe that delivers a mixture of clean air from the air intake filter and oil-rich air from the crankcase vent. The air-oil mixture travels as a mist through the air intake pipe at an initial velocity. When the air-oil mixture enters the conical portion, it expands and loses velocity. As the air-oil mixture slows, the oil that was suspended in the mist and is heavy relative to the air falls out of suspension and settles to the lower- velocity perimeter of a chamber defined by the conical portion, while the lighter air continues into the compressor air inlet. The passive oil collector advantageously removes oil and/or other contaminants from the flow path. By doing so, the fouling of the compressor components such as the compressor wheel and volute is reduced, and the supply of relatively clean compressed air to the engine by the turbocharger is facilitated.

In some aspects, a baffle may be positioned in the flow path, for example along a centerline of the flow exiting the intake tube, to promote coalescence of oil droplets, further removing oil and/or other contaminants from the flow path, reducing fouling of the compressor components and helping to ensure that the turbocharger supplies relatively clean compressed air to the engine.

In some aspects, a cooling jacket surrounds at least a portion of the passive oil collector. The cooling jacket is configured to receive a circulating coolant, and thus cools the surface of the collector. As the air-oil mixture approaches and/or contacts the cooled surface, oil condenses on the cooled surface, further facilitating separation of oil from the air-oil mixture.

Advantageously, the passive oil collector is disposed in the air flow path at the compressor air inlet. Placement of the passive oil collector at the compressor air inlet will not be detrimental to surge performance of the compressor, and may enhance turbocharger operation since it is known that an increased volume ahead of the compressor inlet promotes more stable flow and delays the onset of surge when decreasing mass flow across a speed line. This is advantageous relative to placement of a passive oil collector in the closed crankcase ventilation line upstream of the air intake tube, which provides no positive effect on surge performance.

Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view of a vehicle engine system including an engine, an exhaust gas turbocharger connected to the engine, a closed crankcase ventilation line extending between the engine and an air intake tube of the turbocharger, and a passive oil collector disposed in the air intake tube at a location between the ventilation line and an air inlet of the turbocharger.

Fig. 2 is a side sectional view of the passive oil collector of Fig. 1.

Fig. 3 is a side sectional view of an alternative embodiment passive oil collector illustrating an air intake tube having a tapered end.

Fig. 4 is a side sectional view of another alternative embodiment passive oil collector illustrating an annular oil collection passage.

Fig. 5 is a side sectional view of another alternative embodiment passive oil collector illustrating a baffle disposed in the air flow path.

Fig. 6 is a view of the baffle of the passive oil collector of Fig. 5 as seen along line 6— 6.

Fig. 7 is a view of another baffle of the passive oil collector of Fig. 5 as seen along line 6— 6. Fig. 8 is a side sectional view of another alternative embodiment passive oil collector illustrating a modified cylindrical portion.

Fig. 9 is a side sectional view of another alternative embodiment passive oil collector that includes a cooling jacket surrounding at least a portion of the collector. DETAILED DESCRIPTION

Referring to Fig. 1, a vehicle engine system 100 includes an engine 1, an exhaust gas turbocharger 10, a crankcase vent 6, and a passive oil collector 50. The crankcase vent 6 extends between a crank case 5 of the engine 1 and an air intake pipe 7 that delivers air from an engine air intake device (not shown) to a compressor section 26 of the turbocharger 10. The crankcase vent 6 provides "closed" crankcase ventilation (CCV) since the vent 6 directs crankcase gases from the crankcase 5 to the turbocharger 1 rather than to the environment. The collector 50 is disposed in the air flow path at a location between the vent 6 and an air inlet 32 of the

turbocharger 10, and is configured to facilitate removal of oil from the air flowing into the turbocharger 10 and to control air flow as it enters into the air inlet 32, as discussed further below.

The engine 1 includes cylinders 4 housed in the crankcase 5, an air intake manifold 2 that provides compressed air to each of the cylinders 4, an exhaust gas manifold 3 that receives exhaust gas from each of the cylinders 4, and the vent 6.

The turbocharger 10 includes a turbine section 12, a compressor section 26, and a center bearing housing 22 disposed between and connecting the compressor section 26 to the turbine section 12. The turbine section 12 includes a turbine housing 14 that defines an exhaust gas inlet 18, an exhaust gas outlet 20, and a turbine volute 15 disposed in the fluid path between the exhaust gas inlet 18 and exhaust gas outlet 20. A turbine wheel 16 is disposed in the turbine housing 14 between the turbine volute 15 and the exhaust gas outlet 20. A shaft 24 is connected to the turbine wheel 16, is rotatably supported within in the bearing housing 22, and extends into the compressor section 26. The compressor section 26 includes a compressor housing 28 that defines an air inlet 32, an air outlet 34, and a compressor volute 29. The compressor air inlet 32 is a hollow, cylindrical member that extends coaxially with the rotational axis R of the shaft 24 and has a radial dimension dl . A compressor wheel 30 is disposed in the compressor housing 28 between the air inlet 32 and the compressor volute 29. The compressor wheel 30 is connected to, and driven by, the shaft 24.

In use, the turbine wheel 16 is rotatably driven by an inflow of exhaust gas supplied from the engine exhaust manifold 3. Since the drive shaft 24 connects the turbine wheel 16 to the compressor wheel 30, the rotation of the turbine wheel 16 causes rotation of the compressor wheel 30. As the compressor wheel 30 rotates, it increases the air mass flow rate, airflow density and air pressure delivered to the engine's cylinders 4 via an outflow from the compressor air outlet 34, which is connected to the engine's air intake manifold 2. Referring to Fig. 2, the collector 50 is connected to the compressor air inlet 32 so as to facilitate removal of oil from the air flowing into the turbocharger 10 and control air flow as it enters into the air inlet 32. The collector 50 is a hollow member that includes a first end 52 that is connected to the air intake pipe 7, and a second end 54 that is opposed to the first end 52 and is connected to the compressor air inlet 32. The collector first end 52 includes an inlet opening 57 that receives the air intake pipe 7 so that a terminal end 9 of the intake pipe 7 resides inside the collector 50 at a location spaced apart from the collector first end 52. The inlet opening 57 has a radial dimension d3 that corresponds to the radial dimension d2 of the air intake pipe 7, which in turn corresponds to the compressor inlet radial dimension dl . The collector second end 54 includes an outlet opening 58 that surrounds, and forms a sealed connection with, an outer surface of the compressor air inlet 32. The collector 50 includes a longitudinal axis 60 that extends between the first end 52 and the second end 54. The longitudinal axis 60 is coaxial with the compressor rotational axis R.

A sidewall 62 extends between the collector first end 52 and the collector second end 54.

The sidewall 62 includes a cylindrical portion 64 adjoining the first end 52, and a conical portion 66 extending between the cylindrical portion 64 and the collector second end 54, whereby the radial dimension of the collector 50 is non-uniform along the longitudinal axis 60.

The conical portion 66 has a first, maximum diameter end 68, and a second, minimum diameter end 70 that is axially opposed to the conical portion maximum diameter end 68. The radial dimension of the conical portion 66 decreases along the longitudinal axis 60 from the maximum diameter end 68, having a radial dimension d4, to the minimum diameter end 70, having a radial dimension d5, such that the sidewall 62 in the conical portion 66 forms an angle relative to the longitudinal axis 60. The angle is determined based on air flow rate as it exits the intake pipe 7, and is tuned to facilitate flow to the compressor wheel 30, and thus may be set to accommodate the specific turbocharger application. The minimum diameter end 70 defines the outlet opening 58, and therefore the minimum diameter end radial dimension d5 corresponds to the radial dimension dl of the compressor air inlet 32. On the other hand, the maximum diameter end radial dimension d4 is greater than the radial dimension of the inlet opening d3. Thus, the conical portion 66 has a larger volume than a portion of the intake pipe 7 having the same axial dimension, whereby the collector 50 is enlarged relative to the air intake pipe 7.

When the air-oil mixture exits the air intake pipe 7 and enters the relatively larger conical portion, it expands and loses velocity. As the air-oil mixture slows, the oil that was suspended in the mist and is heavy relative to the air separates from the air and settles to the lower- velocity perimeter of the conical portion 66, while the lighter air continues into the compressor air inlet 32. Since the collector 50 is disposed at the entrance to the compressor air inlet 32, its relatively large volume slows the flow of air from the air intake pipe 7 just before it enters the compressor air inlet 32.

The air intake pipe terminal end 9 lies in a plane PI that is transverse to the longitudinal axis 60 and passes through the maximum diameter end 68 of the conical portion 66. The plane PI lies between, and is axially spaced apart from the inlet opening 58 and the minimum diameter end 70. The cylindrical portion 64 extends axially from the conical portion maximum diameter end 68 toward the intake pipe 7, and serves as an oil collecting region. The cylindrical portion 64 includes a drain line 76 that permits collected oil to return to the engine casing 5 via gravity feed.

In the illustrated embodiment, the air intake tube 7 protrudes through the cylindrical portion 64, such that the intake tube terminal end 9 is spaced apart from the collector first end 52. The cylindrical portion 64 surrounds a circumference of the portion of the intake tube 7 residing within the collector 50. The region defined between the air intake tube 7 and the inner surface of the cylindrical portion 64 provides additional volume that facilitates the reduction of the speed of the air flowing into the collector 50. The ratio of the conical portion maximum diameter end radial dimension d4 to the inlet opening radial dimension d3 is in a range 1.5 to 4.0. For example, in the illustrated embodiment, this ratio is about 2.4. By adjusting the dimensions of this region (e.g., the axial length of the cylindrical portion 64, the difference in radial dimensions of the intake tube 7 and the cylindrical portion 64, etc.), fluid flow into the compressor wheel 30 and the compressor map defining the relationship between pressure ratio and flow rate can be controlled.

Referring to Fig. 3, an alternative embodiment passive oil collector 150 is similar to the passive oil collector 50, and common reference numbers are used to refer to elements that are common to both embodiments. The alternative embodiment passive oil collector 150 includes an air intake tube 107 that tapers inward at the air intake tube terminal end 109. By providing the air intake tube 107 with an inward taper, the velocity of the air flow through the air intake tube 107 will be increased at the terminal end 109, providing a larger velocity change as the air exits the air intake tube 107 and enters the oil collector 150. The larger velocity change further facilitates separation of oil from the air-oil mixture.

Referring to Fig. 4, another alternative embodiment passive oil collector 250 is similar to the passive oil collector 50, and common reference numbers are used to refer to elements that are common to both embodiments. The alternative embodiment passive oil collector 250 includes an annular oil collection passage 276 that extends about a circumference of the cylindrical portion 64. The oil collection passage 276 receives oil collected in the cylindrical portion 64, and the collected oil is returned to the engine casing 5 via gravity feed. By providing the annular oil collection passage 276, the passive oil collector 250 becomes symmetric about the longitudinal axis 66. This configuration simplifies assembly of the oil collector 250 to the turbocharger 10 compared to the earlier-described oil collector 50 in which care must be taken during assembly to position the drain line 76 at a lowermost location.

Referring to Figs. 5-7, another alternative embodiment passive oil collector 350 is similar to the passive oil collector 50, and common reference numbers are used to refer to elements that are common to both embodiments. The alternative embodiment passive oil collector 350 includes a baffle 378 disposed in the conical portion 66. In particular, the baffle 378 is supported by radially extending spokes 380 so as to lie in a plane parallel to the plane PI (Fig. 5). The baffle 378 is centered on the longitudinal axis 60 so as to reside in the centerline of flow exiting the air intake tube 7, and is spaced apart from the air intake tube terminal end 9. In some embodiments, the peripheral shape and dimension of the baffle 378 are set to match the peripheral shape and dimension of the air intake tube terminal end 9. In other embodiments, the peripheral shape of the baffle 378 is set to correspond to the peripheral shape of the conical portion 66, and the dimension of the baffle 378 is set as a proportion of the dimension of the conical portion 66 in a common transverse plane. The baffle may be a solid disk 378 (Fig. 6) or a screen 378' (Fig. 7). The baffle 378 promotes coalescence of oil droplets and separation of oil from the air-oil mixture exiting the air intake tube 7.

Referring to Fig. 8, another alternative embodiment passive oil collector 450 is similar to the passive oil collector 50, and common reference numbers are used to refer to elements that are common to both embodiments. The alternative embodiment passive oil collector 450 includes a solid cylindrical portion 464 having a central passageway 466 that is shaped and dimensioned to receive the air intake tube 7 in a fitted relationship. The cylindrical portion supports the air intake tube 7 within the passive oil collector 450 so that the air intake pipe terminal end 9 lies in the plane PI . In addition, a drain line 476 is provided at a location corresponding to the conical portion maximum diameter end 68. The drain line 476 permits collected oil to return to the engine casing 5 via gravity feed.

Referring to Fig. 9, another alternative embodiment passive oil collector 550 is similar to the passive oil collector 50, and common reference numbers are used to refer to elements that are common to both embodiments. The alternative embodiment passive oil collector 550 includes a cooling jacket 580 that surrounds the conical portion 66. The cooling jacket 580 includes cooling channel 590 defined between a jacket inner surface 582 that contacts an outer surface of the conical portion 66, and a jacket outer surface 584. The cooling jacket 580 includes a fluid inlet port 586 that can be connected to a coolant source (not shown), and a fluid outlet port 580. The fluid inlet and outlet ports 586, 588 permit a coolant to be circulated through the cooling jacket 580, cooling the conical portion of the collector 550. Cooling the conical portion 66 promotes condensation of oil on the conical portion inner surfaces, further facilitating separation of the oil from the air-oil mixture exiting the air intake tube 7.

As previously described, the collector 50 is disposed in the air flow path at a location between the vent 6 and the air inlet 32 of the turbocharger 10 so that the first end 52 of the collector 50 is connected to the air intake pipe 7, and the second end 54 is connected to the compressor air inlet 32. As such, the collector 50 is formed separately from the turbocharger 10 and the intake pipe 7, and is subsequently assembled to these components. However, the collector 50 is not limited to this, and in other implementations may be formed integrally with the air intake pipe or the compressor air inlet.

Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

Claims

We claim: 1. A passive oil collector (50) comprising

an inlet opening (57);

an outlet opening (58);

a longitudinal axis (60) that extends between the inlet opening (57) and the outlet opening

(58);

a conical portion (66) disposed between the inlet opening (57) and the outlet opening

(58), the conical portion (66) having a first end (68) , a second end (70) opposed to the first end (68), and a radial dimension that decreases along the longitudinal axis (60) from a maximum at the first end (68), which is disposed adjacent to the inlet opening (57), to a minimum at the second end (70), which is disposed adjacent to the outlet opening (58), wherein

the maximum radial dimension (d4) of the conical portion (66) is greater than the radial dimension (d3) of the inlet opening (57).

2. The passive oil collector (50) of claim 1, wherein the radial dimension (d3) of the inlet opening (57) is the same as the radial dimension (d5) of the outlet opening (58).

3. The passive oil collector (50) of claim 1, wherein the conical portion (66) second end (70) defines the outlet opening (58), and the conical portion first end (68) is axially spaced apart from the inlet opening (57).

4. The passive oil collector (50) of claim 3, further comprising an intake tube (7) that extends through the inlet opening (57), wherein a terminal end (9) of the intake tube lies in a plane (PI) that is transverse to the longitudinal axis (60) and passes through the conical portion first end (68).

5. The passive oil collector (50) of claim 1, further comprising a cylindrical collecting portion (64) extending axially from the conical portion first end (68), the collection portion including a drain outlet (76).

6. The passive oil collector (50) of claim 5, further comprising an intake tube (7) that extends through the inlet opening (57), and the collecting portion (64) surrounds a circumference of a portion of the intake tube.

7. The passive oil collector (50) of claim 1, wherein a ratio of the conical portion first end radial dimension (d4) to the inlet opening radial dimension (d3) is in a range 1.5 to 4.0.

8. The passive oil collector (50) of claim 1, further comprising a baffle (378) disposed between the conical portion first end (68) and conical portion second end (70).

9. The passive oil collector (50) of claim 8, wherein the baffle (378) is a solid disc.

10. The passive oil collector (50) of claim 1, further comprising a cooling jacket (580) that surrounds the conical portion (66).

11. An exhaust gas turbocharger (10) comprising:

a turbine section (12) including a turbine wheel (16);

a compressor section (26) comprising:

a compressor housing (28) defining a compressor air inlet (32);

a compressor wheel (30) disposed within the compressor housing (28) adjacent to the compressor air inlet (32), the compressor wheel (30) connected to the turbine wheel (16) via a shaft (24); and

a passive oil collector (50) disposed at the compressor air inlet (32), the collector (50) comprising

an inlet opening (57);

an outlet opening (58);

a longitudinal axis (60) that extends between the inlet opening (57) and the outlet opening (58);

a conical portion (66) disposed between the inlet opening (57) and the outlet opening (58), the conical portion (66) having a first end (68), a second end (70) opposed to the first end (68), and a radial dimension that decreases along the longitudinal axis (60) from a maximum at the first end (68), which is disposed adjacent to the inlet opening (57), to a minimum at the second end (70), which is disposed adjacent to the outlet opening (58), wherein the maximum radial dimension (d4) of the conical portion (66) is greater than the radial dimension (d3) of the inlet opening (57).

12. The turbocharger (10) of claim 11, wherein the radial dimension (d3) of the inlet opening (57) is the same as the radial dimension (d5) of the outlet opening (58).

13. The turbocharger (10) of claim 11, further comprising a cylindrical collecting portion (64) extending axially from the conical portion first end (68), the collection portion including a drain outlet (76).

14. The turbocharger (10) of claim 11, further comprising a baffle (378) disposed between the conical portion first end (68) and conical portion second end (70).

15. The turbocharger (10) of claim 11, further comprising a cooling jacket (580) that surrounds the conical portion (66).