Patent Application
20080286127
Subject matter disclosed herein relates generally to systems that include a compressor for intake air for an internal combustion engine.
Turbochargers produce aerodynamic noises that can annoy vehicle passengers as well as those in the surrounding environment. Such noises can propagate to other engine system components where acoustic energy may be detrimental and increase wear. In general, most people view turbocharger noise as a nuisance.
For a properly operating, conventional turbocharger, the intake air compressor and the exhaust turbine generate noise. Characteristics of generated noise typically change with operating conditions. For example, as a compressor moves toward surge (a non-optimal operating condition), noise generation can intensify due to flow separation at the suction side of the compressor blades. This noise can propagate through the high density compressed air as well as through structures connected to the compressor.
While turbocharger noise can lead to complaints, noise can also provide information as to particular issues associated with turbocharging (e.g., compressor wheel imbalance, etc.). However, upon inspection, most noise complaints are determined to be associated with normal turbocharger operation. Thus, techniques that reduce turbocharger noise have the potential to reduce not only complaints but also unwarranted service calls.
An exemplary noise damper for a compressor of a turbocharger includes a compressor housing comprising a cavity substantially adjacent a gas flow surface of a conduit to a compressed gas outlet of the compressor housing and an insert that spans the cavity and forms a wall of the cavity where the wall includes one or more openings to the cavity to thereby allow acoustic energy to be damped by the cavity. Various other exemplary technologies are also disclosed.
A more complete understanding of the various method, systems and/or arrangements described herein, and equivalents thereof, may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein:
Various exemplary methods, devices, systems, arrangements, etc., disclosed herein address issues related to technology associated with turbochargers. Turbochargers are frequently utilized to increase the output of an internal combustion engine. A turbocharger generally acts to extract energy from the exhaust gas and to provide energy to intake air, which may be combined with fuel to form combustion gas.
Referring to
The turbocharger 120 acts to extract energy from the exhaust and to provide energy to intake air, which may be combined with fuel to form combustion gas. As shown in
Referring to the turbine unit 126, such a turbine unit optionally includes a variable geometry mechanism and a variable geometry controller. The variable geometry mechanism and variable geometry controller optionally include features such as those associated with commercially available variable geometry turbochargers (VGTs). Commercially available VGTs include, for example, the GARRETT® VNT™ and AVNT™ turbochargers, which use multiple adjustable vanes to control the flow of exhaust across a turbine. An exemplary turbocharger may employ wastegate technology as an alternative or in addition to variable geometry technology.
Some turbochargers include an electric motor operably coupled to a shaft to drive a compressor using electrical energy, for example, where exhaust energy alone is insufficient to achieve a desired level of boost. In some instances, a turbocharger may include a generator configured to generate electrical energy from exhaust gas.
As mentioned in the background section, a turbocharger generates noise.
As the noise damper 250 is integral with the compressor housing 240, a manufacturer can ensure that a compressor installation will have certain noise characteristics. In turn, such characteristics may be helpful for investigating complaints or issues associated with turbocharger operation. While the noise damper 250 of
The insert 370 may be a thin sheet (e.g., metal, plastic or composite material) that forms an inner wall of an acoustic damper section. Features or properties of the sheet can be tailored to provide accuracy as to damper characteristics and damper efficiency.
With respect to the noise damper 250 of
In the example of
When assembled, the insert 370 has an insert outer diameter “ODI” that substantially matches the notch diameter DN and an insert inner diameter “IDI” that substantially matches the conduit inner diameter IDCon. The insert 370 also has an axial length “ΔxI” that substantially matches the cavity length ΔxC plus twice the notch axial length ΔxN. Thus, upon assembly, the insert 370 forms a wall of a cavity 363 defined by the conduit 360 and provides openings to the cavity 363 that allow for acoustic energy damping.
A close-up view of the boundary between the conduit 360 and the insert 370 indicates how the inner diameter of the conduit 360 and the inner diameter of the insert 370 match to form a substantially continuous transition region along a flow surface (see, e.g., flow vectors).
As shown in
As described herein, an exemplary noise damper for a compressor of a turbocharger includes a compressor housing manufactured with a cavity substantially adjacent a gas flow surface of a conduit to a compressed gas outlet of the compressor housing and an insert that spans the cavity and forms a wall of the cavity where the wall includes one or more openings to the cavity to that allow acoustic energy to be damped by the cavity. As shown in
Where desirable, an exemplary noise damper may include a notch located directly adjacent a cavity and configured to secure an insert. For example, an insert may have a wall thickness and the notch a depth that matches the wall thickness of the insert to thereby form a substantially continuous transition between a gas flow surface of the conduit and the insert.
An exemplary noise damper may be made of a resilient material capable of being radially compressed, inserted into the lumen of a conduit and radially expanded to secure the insert in a location in the conduit that spans a cavity.
Referring again to
An exemplary method for manufacturing a compressor housing that includes a noise damper includes casting a compressor housing where the compressor housing includes a compressor scroll, an outlet for compressed gas, a conduit between the compressor scroll and the outlet for compressed gas and a cavity located in a wall of the conduit and inserting a resilient insert into the conduit where the resilient insert spans the cavity and includes one or more openings to the cavity. In such a method, the process of inserting the insert can include compressing the resilient insert, inserting the resilient insert into the conduit via the outlet for compressed gas and allowing the resilient insert to expand in the conduit. As already mentioned, a compressor housing can include a ridge that spans a length of a cavity. According to such a configuration, a method can include supporting the resilient insert at least in part by the ridge.
As described herein, an exemplary insert can include one or more openings that include an arc length dimension that exceeds an axial dimension. Consider the insert 575 and the substantially rectangular openings 576 that include a length oriented orthogonal to a gas flow direction (x-axis) and an axial dimension (e.g., width) that is less than the length.
Referring to the compressor housing 240, such a housing is optionally cast with one or multiple chambers in the compressor scroll extension section 246 to provide appropriate damper cavity volumes.
To form one or more dampers, one or more thin sheets can be rounded to form a substantially cylindrical form that may be of a slightly larger diameter than the inner diameter of the compressor scroll extension section 246 where the cavity(ies) exist. As indicated in various examples, a thin sheet need not be completely closed to thereby allow reduction of its diameter under an applied force and to extend to a larger diameter when released in its appropriate location. Assembly may compress and then release a thin sheet in the compressor scroll extension section of a compressor housing. Such a thin sheet stays in place by the fact that its diameter is slightly larger than the diameter where it is fitted (e.g., consider a compressible/expandable retaining ring). In other examples, an insert may be made from a resilient material (e.g., optionally memory material) that can be shaped for insertion and then expanded (e.g., via heat application, natural resiliency, etc.) to fit snugly into the proper location.
As indicated in
As described herein, a sleeve may form a cavity wall in a conduit where the sleeve is fixed by its own stiffness (e.g., like a spring). Such an arrangement of can ease manufacturability and allow for a variety of design not readily achievable by machining or casting.
Although exemplary methods, devices, systems, etc., have been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claimed methods, devices, systems, etc.
