Patent Application
20070295824
Referring now to
The exhaust system assembly 12 forms an exhaust gas passageway 14 for gases emitted from an engine 16. The passageway 14 is formed with an exhaust inlet pipe 18, having an inlet 20 connected to an exhaust outlet of the engine 22, and an exhaust outlet pipe 24, having an outlet 26 for venting the exhaust gases to the atmosphere. The heating system assembly 10 is located downstream of the exhaust inlet pipe 18 and upstream of the exhaust outlet pipe 24 in the direction of flow of the exhaust gases.
The exhaust system assembly 12 is preferably mounted on a chassis member 28 using conventional mounting structures 30. The exhaust system assembly 12 preferably extends longitudinally along the length of the bus.
In the direction of flow of the exhaust gases, the exhaust system assembly 12 incorporates aftertreatment devices, and specifically, includes an oxidation catalyst member 32 and a particulate filter 34. The oxidation catalyst member 32 is a conventional flow-through device that oxidizes unburned fuel and oil to reduce harmful emissions. Further, the particulate filter 34 is a conventional filter that removes particulate matter from the exhaust gases.
The heating system assembly 10 includes the exhaust system assembly 12, and also includes a quasi “black body” heat collector 36, which is disposed downstream of the particulate filter 34. The term “black body” refers to an ideal body that, if it existed, would have 100% absorption, 0% reflection, and 100% emission of all radiation that hits the body. While ideal black bodies are not known to exist, quasi black bodies are known bodies that approximate the behavior of an ideal black body. For example, certain materials, such as carbon in its graphite form, absorb 97% of the radiation that hit it. Additionally, it is also known to coat objects with paint that exhibits high absorption with transmittance and reflectance near zero for infrared energy.
Referring now to
Extending to the heat collector 36 from the HVAC system 43 of the bus 11 is an inlet conduit 42. The inlet conduit 42 is in fluid connection with the tubes 40 of the heat collector 36. The blower motor of the HVAC system 43 forces air through the inlet conduit 42 and into the tubes 40 in the heat collector 36. In the tubes 40, the air is heated as it flows through the quasi black body heat collector 36. Then, the heated air exits the tubes 40 through an outlet conduit 44. The outlet conduit 44 is in fluid communication with the HVAC system 43 and permits the forced convection of heated air to the body or interior compartment of the bus 11.
While the present heating system assembly 10 includes one quasi black body heat collector 36 located downstream of the particulate filter 34, it is contemplated that a plurality of heat collectors can be located along the exhaust system 12. Further, while the preferred quasi black body heat collector 36 has a plurality of tubes 40 coated with high absorption paint, it is contemplated that the tubes can be made of materials exhibiting high absorption and emission of radiation.
When the temperature of the exhaust gases becomes too hot, the quasi black body heat collector 36 includes at least one port 46 and one port cover 48 that can be selectively opened and closed to draw in ambient air. Preferably, the ports 46 are located on the housing 38 of the heat collector 36 such that they provide fluid communication between the ambient and the exhaust gases. The ports 46 are configured in such that when they are opened, some of the exhaust gases are diverted to the environment thus reducing the exhaust gas mass flow, and hence, heat transfer to the tubes 40.
The port cover 48 is preferably hingeably attached to the port 46. Further, the port cover 48 and the materials surrounding the port 46 are preferably made of a ferromagnetic material such that the port cover is magnetically attracted to a closed position with respect to the port. In the preferred embodiment, when the temperature of the metals forming the heat collector 36 reach the Curie point, (i.e. the temperature at which a ferromagnetic material loses it's magnetization), the port cover 48 automatically swings open. That is, when the temperature reaches the Curie point, the port cover 48 is no longer attracted to the material surrounding the port 46, and the port cover opens. Alternatively, a controller, such as the engine controller unit (ECU) or a body controller (not shown), could automatically open the ports 46 when the temperature of the exhaust gases reaches a predetermined temperature.
While heat from the present heating system 10 is configured to supplement the heat conventionally derived directly from the engine 16, it is contemplated that the present heating system can completely substitute for the heat derived from the engine. Further, it is contemplated that the present heating system 10 can be used in combination with any other known heating systems.
While particular embodiments of the present heating system 10 have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
