The invention relates to devices mounted on truck exhaust systems to dilute and diffuse the exhaust gas as it is released from the truck
Exhaust treatment devices in trucks require maintenance procedures that can create situations where exhaust temperatures are much higher than during normal use of the vehicle. For example, diesel particulate filters, which trap soot and other particulate matter in the exhaust stream, require a regeneration process to burn off the collected soot. The process requires that the temperature of the exhaust entering the diesel particulate filter be in excess of 600° C. Normal operating exhaust temperature is about 425° C. for a diesel engine in a truck.
Exhausting the higher temperature gases to atmosphere poses difficulties. A truck typically has an exhaust stack pipe rising from the chassis adjacent to the truck cab. High temperature exhaust can produce a hot spot on the truck cab or trailer.
In addition, in vocational trucks (dump trucks, trash hauling trucks, etc), the exhaust stack and the exhaust gases must not interfere with the operation of the body, lifting the dump body, for example.
What is needed is a device to reduce the exhaust temperature without drastically affecting the exhaust backpressure.
According to a preferred embodiment of the invention suitable for vocational trucks such as dump trucks and trash collection trucks, a diffuser box is mounted at the end of the exhaust stack. The diffuser box is mounted downstream of the catalyst and diesel particulate filter (DPF) in the exhaust system. The diffuser box allows exhaust gases to dissipate over a larger area than does a standard exhaust pipe, which helps avoid concentrations of hot gases. A first embodiment of a diffuser box includes a side outlet. A second embodiment has a top outlet. An inlet of the diffuser box is mountable on an outlet of an exhaust stack pipe. Both embodiments incorporate a dispersing element mounted in line with the box inlet to cause the exhaust gases to flow throughout the box before exiting so that there are no localized high temperatures. According to a preferred embodiment, the dispersing element is cone shaped and disposed with the apex of the cone point toward the box inlet.
The exhaust gases then exit the box through a meshed grill to the atmosphere. The meshed area has been optimized to create a larger area for dissipation compared to the normal round exhaust pipe outlet. This also minimizes the affect on backpressure.
The invention will be better understood by reference to the following detailed description read in conjunction with the appended drawings, in which:
The invention relates to devices that are mounted on the end of a truck exhaust system at the point where exhaust gas is released to the surrounding air. The devices of this invention diffuse the exhaust gas over a wider area than a typical exhaust stack pipe to prevent hot spots and dissipate heat more quickly.
A diffuser in accordance with the invention shown in
A dispersing element 20 is mounted in the box at the outlet of the stack pipe 5. According to the illustrated embodiment, the dispersing element is cone shaped. The dispersing element 20 is mounted on two bars in disposition over the opening in the stack pipe 5 and in the flow path of the exhaust gas. The point of the cone faces into the gas flow. The dispersing element 20 presents a surface that diverts the exhaust gas from axial flow to flow radially outward into the box 10 volume before exiting the box. This allows the gas to diffuse over the area defined by the top covering 12 as it exits the box 10. The dispersing element 20 is shown with its cone axis at an angle to the axial direction of the stack pipe 5. Alternatively, the dispersing element 20 may be mounted so that the point of the cone, and accordingly the cone axis, is aligned with the flow direction.
Alternatively, both the top wall and front portion of the peripheral wall could be formed with mesh to allow diffuse flow in a broader area.
The dispersing element 20 is illustrated as a cone. However, other shapes as will occur to those skilled in the art may be substituted if capable of diverting gas flow from a substantially linear flow to a radially outwardly directed flow.
Analysis of both boxes 10, 30 shows that the temperature of the exhaust during DPF regeneration exiting the boxes will be at a temperature comparable to normal exhaust temperatures (not during filter regeneration) at about six inches from the box outlet.
Advantageously, as shown in
The invention has been described in terms of preferred embodiments and structure; however those skilled in the art will understand that substitutions and variations may be made without departing from the scope of the invention as defined in the appended claims.
This application claims the benefit of U.S. Provisional Patent Application No. 60/842,842, filed Sep. 7, 2006.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US06/48888 | 12/21/2006 | WO | 00 | 3/6/2009 |
Number | Date | Country | |
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60842842 | Sep 2006 | US |