Abstract:
Temperature control devices have become common to cool the exhaust stream from a diesel particulate filter before release into the environment. To further cool the filtered exhaust stream, a temperature control device has plates that are approximately parallel and in a spaced apart relationship. A vent is located between the plates. The plates have apertures. A shield is also used.

Description:
BACKGROUND 
       [0001]    Embodiments disclosed herein relate to exhaust systems and more particularly to the reduction of exhaust gas temperature from a diesel particulate filtering system. 
         [0002]    Elevated exhaust gas temperatures from the tail pipes of diesel engine equipped motor vehicles have become a greater problem with the introduction of diesel particulate trap/filters (DPF) and the need to regenerate these filters. Diesel particulate filters remove unburned and partially burned hydrocarbons from the exhaust streams produced by diesel engines. A DPF may be periodically regenerated by raising the temperature in the filter sufficiently to accelerate the oxidation of or ignite the particulate matter trapped in the filter. This process, once initiated, further increases the temperature of the exhaust stream downstream from the filter. The increase in the temperature of the exhaust may singe passers-by, particularly where the exhaust is discharged near ground level, and add stress on exhaust pipes. 
         [0003]    Some prior systems achieved exhaust gas cooling as a byproduct of cooling a component, such as a muffler, in the exhaust system. In some contemporary pollution control schemes, components of the exhaust gas treatment system must run hot in order to operate or regenerate, making it undesirable to reduce exhaust gas temperature ahead of the component in question or to reduce the temperature of the component itself. For example, diesel particulate filter regeneration requires maintaining the temperature of the filter during regeneration. 
         [0004]    A conventional method of cooling exhaust gases is an “in-can” or “in-muffler” venturi device. In the path of exhaust gas flow, the venturi device is located downstream of the muffler and upstream of the tailpipe, and uses ambient air to lower the overall temperature of the gases emitted from the tailpipe. In the venturi device, a “cold pipe” draws in ambient air, and sits within a “hot pipe” that forms the path of flow of the exhaust gases. The exhaust gases travel within the hot pipe and around the cold pipe. As the exhaust gases travel around the cold pipe, the exhaust gases are cooled. At an outlet of the cold pipe, the ambient gases and the exhaust gases are mixed in the tailpipe for further cooling. However, new emissions laws require that the exhaust gas temperatures be lowered beyond the capabilities of the conventional in-muffler venturi device. 
         [0005]    Reducing the exhaust gas temperature after leaving the diesel particulate filter can be accomplished with a temperature control device. The temperature control device typically has inlets that allow fresh air into the device to mix the exhaust gas with the air to reduce the temperature of the exhaust. 
       SUMMARY 
       [0006]    A temperature control device for an exhaust apparatus for a motor vehicle has a generally cylindrical body. Plates are approximately parallel in a spaced apart relationship and located at least partially within the body. A vent is located between the plates. Each plate has a peripheral edge and at least one aperture. Peripheral apertures are arranged radially between a central aperture and the edge. A shield extends radially and outwardly from the body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a plan view of a vehicle equipped with an exhaust system with a temperature control device; 
           [0008]      FIG. 2  is side view of an exhaust system with a temperature control device; 
           [0009]      FIG. 3  is a perspective view of a temperature control device; 
           [0010]      FIG. 4  is a perspective view of a temperature control device; 
           [0011]      FIG. 5  is a bottom perspective view of a plate of a temperature control device; 
           [0012]      FIG. 6  is top plan view of a plate of a temperature control device; 
           [0013]      FIG. 7  is a bottom perspective view of one embodiment of a temperature control device; and 
           [0014]      FIG. 8  is a perspective view of one embodiment of a temperature control device. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to the drawings and in particular referring to  FIG. 1 , a vehicle such as a school bus or a truck  11 , is typically equipped with a diesel engine  12  and an exhaust system  10  requiring use of a diesel particulate filter (DPF). The exhaust system  10  is installed on the motor vehicle  11  to the chassis  28  horizontally or under the vehicle  11 . 
         [0016]    The engine  12  is in fluid communication with the filter assembly  13  through entrance tubing  14  at the inlet side of the filter assembly  13 . Treated exhaust flows from the filter assembly  13  through exit tubing  16 , which can include a tailpipe, at the outlet side of the filter assembly  13 . 
         [0017]    The filter assembly  13  has a housing  22  and a diesel particulate filter  20  disposed therein. The filter assembly  13  may connect with a catalytic device  18  located between the engine  12  and the filter assembly  13 . The housing  22  has a first conduit  24  in fluid communication with the entrance tubing  14 . The opposite second conduit  26  is in fluid communication with the exit tubing  16 . 
         [0018]    A temperature control device  30  is installed in the exhaust system  10  to lower the temperature of the filtered exhaust. The temperature control device  30  is in fluid communication with the diesel particulate filter  20  to receive filtered exhaust, such as from the second conduit  26 . The temperature control device  30  is also in fluid communication with the exit tubing  16 , which is in fluid communication with the outside air. 
         [0019]    The temperature control device  30  includes a generally cylindrical body  64 . At least two approximately parallel plates  32 ,  34  are located at least partially within the body  64  in a spaced apart relationship. Vent  72  for receiving ambient air is located between the pair of plates  32 ,  34 . A shield  46  extends outwardly from the body  64  of the temperature control device  30 . The body  64  can include entrance tube  74  at one end, exit tube  76  at the opposite end and any inner tubing  78  located between the plates. Plates  32 ,  34  are approximately perpendicular to the length of the body  64  and can be approximately circular. 
         [0020]    Plates  32 ,  34 , vent  72  and shield  46  can be part of plate assembly  60 ,  61 . The shield  46  can extend from an edge  44  of at least one of the plates  32 ,  34 . 
         [0021]    Each plate  32 ,  34  has one or more aperture, such as central aperture  36  and peripheral apertures  40  arranged radially around the central aperture  36  between a peripheral edge  44  and the central aperture  36 . Approximately circular apertures are shown, although other aperture shapes can be used. 
         [0022]    Each aperture can have an aperture wall. A central aperture wall  38  surrounds the central aperture  36  and extends from the plate  32 . Each peripheral aperture  40  has a peripheral aperture wall  42  surrounding the peripheral aperture  40  and extending from the plate  32 . The aperture walls  38 ,  42  can be approximately cylindrical or can have a smaller diameter distal to the plate  32  when the aperture is circular. The aperture walls will have other configurations when the aperture is not approximately circular. The aperture walls can be part of only one of the plates. 
         [0023]    One or more spacers  48  can separate one plate  32  from the other plate  34  and can be in any configuration that allows the separation. The spacer can be a separate component attaching to shield  46  of at least one of the plates. Spacer  48  alternatively is formed from shield  46  of at least one of the plates  32 ,  34 . Spacer  48  can be located between edge  44  of a plate and the outer border  50  of at the of shield  46  or at the outer border  50 . The spacer  48  shown in  FIG. 5  has opposite side walls  52 ,  53  extending from the outer border  50  toward the apertures. Inner wall  54  is located between side walls  52 ,  53 . A base wall  56  can connect the side walls  52 ,  53  and inner wall  54 . The side walls  52 ,  53  and inner wall  54  can be angled or slanted. The outer edge of spacer  48  formed by side walls  52 ,  53  and base wall  56  can be approximately U-shaped to form a notch. 
         [0024]      FIGS. 3 and 4  show plates  32 ,  34  disposed in a spaced apart relationship and nesting together to form plate assembly  60 . A first plate  32  nests within second plate  34  after rotating the plate to allow the spacers  48  of one plate to engage the shield  46  of the other plate. Spacers  48  can be used to attach the plates  32 ,  34  to together. A vent  72  forms between the plates  32 ,  34  to allow ambient air into the temperature control device  30 . Aperture walls of the first plate  32  insert within the apertures of the second plate  34 . If both plates have aperture walls, the aperture walls of the first plate  32  can nest within the aperture walls of the second plate  34 . Temperature control device  30  can have any number of plate assemblies  60 , such as two shown in  FIG. 8  and four shown in  FIGS. 3 and 4 . Temperature control device  30  attaches to the second conduit  26  at the entrance tube  74  and the exit tubing  16  at the opposite exit tube  76 . Inner tubing  78  is located between at least two plate assemblies  60 . 
         [0025]    In temperature control device  31 , at least two plates  32 ,  34  are nested together and seated on spacers  48  of at least one of the plates to form plate assembly  61 . The aperture walls  38 ,  42  of the first plate  32  insert within the apertures of the second plate  34 . If both plates have aperture walls, the aperture walls of the first plate  32  can nest within the aperture walls of the second plate  34 . In  FIG. 7 , every other plate of plate assembly  61  is rotated with the spacer  48  engaging the shield  46  of the other plate. A vent forms between the plates to allow ambient air into the temperature control device  31 . Temperature control device  31  attaches to the second conduit  26  at the entrance tube  74  and the exit tubing  16  at the opposite exit tube  76 . 
         [0026]    The temperature control device installs within the exhaust system downstream from the DPF. The temperature control device can have the shield open either upstream or downstream from the DPF. Ambient air is drawn into the temperature control device through the vent. The ambient air mixes with the exhaust within the temperature control device and cools the exhaust. 
         [0027]    While a shield is shown in the Figures, a duct or other similar apparatus can be used to surround the vents of the temperature control device in place of the shield.