Patent Application
20090232592
The subject invention relates to an end cap mounting module, and more particularly relates to an end cap mounting module that is cast as a single-piece component.
Exhaust systems are widely known and used with combustion engines. An exhaust system includes exhaust tubes that convey hot exhaust gases from the engine to other exhaust system components, such as catalytic converters, mufflers, resonators, etc. As known, the catalytic converter houses a catalyst through which the exhaust gas and excess air are passed so that carbon monoxide and hydrocarbon pollutants are oxidized to carbon dioxide and water.
An end cap mounting module is mounted to one end of the catalytic converter. The end cap mounting module includes an outlet to an exhaust pipe. Typically, the end cap mounting module includes a sensor boss and mounting structure such that the end cap mounting module can be mounted to a vehicle structure. Traditionally, the end cap mounting module has been formed from stamped metal sheet portions that are welded together. The sensor boss is a separate piece that is welded to an outer surface of the end cap mounting module. The sensor boss comprises an elongated body that extends outwardly from the outer surface by a sufficient length such that there is adequate room to perform the welding operation to attach the sensor boss to the end cap mounting module. The mounting structure has also traditionally comprised separate mounting brackets or mounting supports that are welded to the outer surface of the end cap mounting module.
During operation, high load forces into the catalytic converter and end cap mounting module place significant stress levels on weld joint interfaces, especially those interfaces for the mounting structure. These stress levels can cause cracking at the weld joint interfaces, which adversely affects the durability of the part and can lead to premature failure.
Further, the mounting structure and sensor boss portions are larger than they need to be in order to accommodate the welding operations for their respective attachment to the end cap mounting module. As such, the traditional configuration takes up a significant amount of the packaging space available for the exhaust system.
Another disadvantage with traditional configurations concerns debris collection. Bolts and other surfaces with flat angles in the stamped configuration form pinch points for collecting debris, which is undesirable.
Therefore, there is a need to provide an end cap mounting module that provides increased durability, eliminates pinch points for debris collection, and which is a more compact configuration such that packaging space can be freed up for other components. This invention addresses those needs while avoiding the shortcomings and drawbacks of the prior art.
An end cap mounting module includes an end cap body that is cast as a single-piece component. The single-piece component includes a first mount interface for connection to a catalytic converter and a second mount interface for connection to an exhaust pipe.
In one example, a single-piece end cap body is cast from a cast iron material.
In one example, the single-piece end cap body includes an integrally formed sensor boss that is cast as part of the single-piece component.
In one example, the single-piece end cap body includes at least one integrally formed fastener boss that is cast as part of the single-piece component.
In one example, the single-piece end cap body includes a continuous and uninterrupted surface that extends from the first mount interface to the second mount interface.
In one example, the first mount interface comprises a first opening defining a first center axis and the second mount interface comprises a second opening defining a second center axis that is perpendicular to the first center axis.
The single-piece cast end cap body provides a more durable and compact configuration that eliminates pinch points for debris collection. These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
As shown in
As shown in
The single-piece end cap body 16 also includes an integrally cast sensor boss 22. The sensor boss 22 extends outwardly from an outer surface 24 of the single-piece end cap body 16 and includes an opening 26 into which a sensor (not shown) can be inserted. The opening 26 is machined into the part after casting.
The single-piece end cap body 16 also includes an integrally cast mount structure 30. In the example shown, the mount structure 30 comprises a plurality of discrete fastener bosses 32 that are spaced circumferentially about the single-piece end cap body 16. Each fastener boss 32 includes a threaded opening 34 to receive a fastener such that the end cap mounting module 10 can be secured to a vehicle structure. Again, by integrally casting the mount structure 30 as part of the single-piece end cap body 16, the overall packaging space required for the end cap mounting module 10 is reduced because the size of the mount structure can be reduced due to the elimination of a welding attachment operation.
As shown in
A tubular portion 48 extends outwardly from the circumferential wall portion 42. The sensor boss 22 is located on the tubular portion 48. The length of the tubular portion 48 is minimized compared to prior designs due to the elimination of a weld attachment interface, i.e. additional weld clearances are no longer required for attachment of the sensor boss 22 so that the length of the tubular portion 48 can be reduced. As such, the overall packaging space required for the end cap mounting module 10 is reduced.
The tubular portion 48 terminates at the second attachment interface 20. The second mount interface 20 comprises a circular opening that connects to the exhaust pipe 14. The second mount interface 20 can be directly connected to the exhaust pipe 14. Optionally, an integrated flange component 50, such as a marmon flange for example, can be used at the second mount interface 20 to connect the end cap mounting module 10 to the exhaust pipe 14. The circular opening of the second mount interface 20 defines a second center axis C2 (
Optionally, a heat shield insert 56 can be mounted within the internal cavity 44. The heat shield insert 56 lowers outer skin temperatures for the end cap mounting module 10.
The cast single-piece end cap body 16 provides a more structurally sound and more durable component than prior art stamped modules. Casting the single-piece end cap body 16 as a single-piece component increases the durability of the end cap mounting module because multiple weld joint interfaces have been eliminated. Further, costs can be more tightly controlled for such a cast component. Additionally, the casting provides smooth contours that are resistive to debris collection. Further, strength in the mounting area is improved such that a pedestal type mount configuration can be utilized without a stanchion.
The casting also has improved sound characteristics when compared to prior stamped configurations. Using a casting increases a resonant frequency of the component to range that is typically outside the operation of the engine/vehicle. Further, the casting offers a dynamic stiffness that raises the natural frequency of the component itself.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
