Patent Application
20150059715
The present disclosure relates to an exhaust gas recirculation (“EGR”) cooler mount. More specifically, the present disclosure relates to an EGR mount comprising a leak off passage.
All engines—diesel, gasoline, propane, and natural gas—produce exhaust gas containing carbon monoxide, hydrocarbons, and nitrogen oxides. These emissions are the result of incomplete combustion. Diesel engines also produce particulate matter. As more government focus is being placed on health and environmental issues, agencies around the world are enacting more stringent emission's laws.
Because so many diesel engines are used in trucks, the U.S. Environmental Protection Agency and its counterparts in Europe and Japan first focused on setting emissions regulations for the on-road market. While the worldwide regulation of nonroad diesel engines came later, the pace of cleanup and rate of improvement has been more aggressive for nonroad engines than for on-road engines. Manufacturers of nonroad diesel engines are expected to meet set emissions regulations. For example, Tier 3 emissions regulations required an approximate 65 percent reduction in particulate matter (PM) and a 60 percent reduction in NOx from 1996 levels. As a further example, Interim Tier 4 regulations required a 90 percent reduction in PM along with a 50 percent drop in NOx. Still further, Final Tier 4 regulations, which will be fully implemented by 2015, will take PM and NOx emissions to near-zero levels.
One known technique for reducing unwanted NOx involves introducing chemically inert gases into the fresh air flow stream for subsequent combustion. By reducing the oxygen concentration of the resulting charge to be combusted, the fuel burns slower and peak combustion temperatures are accordingly reduced, thereby lowering the production of NOx. In an internal combustion engine environment, such chemically inert gases are readily abundant in the form of exhaust gases, and one known method for achieving the foregoing result is through the use of an EGR system operable to controllably introduce (i.e., recirculate) exhaust gas from the exhaust manifold into the fresh air stream flowing to an intake manifold. Known EGR systems comprise EGR coolers, and the EGR coolers require a secure mounting location.
An EGR cooler mount comprising an inlet port, an outlet port positioned downstream of the inlet port, and a leak off passage. The inlet port is configured to receive fuel, and the outlet port is configured to distribute the fuel to a fuel tank. The leak off passage is positioned fluidly between the inlet port and the outlet port.
The detailed description of the drawings refers to the accompanying figures in which:
Referring to
The EGR cooler mount 110 may be mounted to at least one of an engine block 112 and an engine head 113, via a plurality of mounting posts 121 and cooler mounting fasteners (not shown), the cooler mounting fasteners being, for example, socket head cap screws. As illustrated, spring pins 126 may be used for positioning and an aligning the EGR cooler mount 110 during installation. As shown, the EGR cooler mount 110 may comprise other, additional mounting features and apertures, so that tubes, sensors, wiring harness, aftertreatment devices, and the like can be mounted thereto.
The number of straps 119 used in a given application (i.e., one or more) may depend on the length and weight of the EGR cooler 118. Although the straps 119 are shown as smooth straps, they may take other forms, such as corrugated straps. The EGR cooler 118 is configured to cool the exhaust gas, the exhaust gas being rerouted to the intake system (not shown) so as to reduce NOx levels in the exhaust gas entering the atmosphere.
Exhaust gas from the engine 106 may enter the EGR cooler 118, via an exhaust gas inlet 151, and the exhaust gas may then exit the EGR cooler 118, via an exhaust gas outlet 149, and be rerouted back to the engine 106. Engine coolant may enter the EGR cooler 118 via a coolant inlet 143, and it may exit the EGR cooler 118 via a coolant outlet 142. The exhaust gas transfers heat to the engine coolant. In the embodiment shown, the exhaust gas flow direction is counter to the engine coolant flow direction, though in other embodiments of the power system 100, they could flow in the same direction relative to one another.
The EGR cooler 118 may comprise a first piece 137, a second piece 138, and a welded joint 139, wherein welded joint 139 may join the first piece 137 and the second piece 138. The welded joint 139 may be an overlapping joint. Exemplarily, the first piece 137 and the second piece 138 may be made of stainless steel (or various other kinds of ferrous materials). In the illustrated embodiment, the first piece 137 is shown as a lower piece, and the second piece 138 is shown as an upper piece. In other embodiments, however, the first piece 137 and the second piece 138 may be oriented differently, such as, for example, side-by-side to one another. Additionally, in some embodiments, the EGR cooler 118 may comprise a separate inlet casting and a separate outlet casting, both of which may be made of stainless steel (or various other kinds of ferrous materials). The straps 119 may be made of, for example, 1008 steel, 1020 steel, stainless steel (or various other kinds of ferrous materials). The EGR cooler mount 110—which may be made of, for example, cast iron—may comprise a first mounting face 123 and a second mounting face 124. A plurality of fasteners 117 and may secure the straps 119 to the EGR cooler mount 110.
The EGR cooler mount 110 may comprise an inlet port 155, an outlet port 171, and a leak off passage 182. An inlet port fitting 154 may be positioned in the inlet port 155, the inlet port fitting 154 being, for example, a line nut that cooperates with a fitting installed in the EGR cooler mount 110, so as to form an o-ring face seal connection. As shown, a tube 191 may be fluidly coupled to—and positioned upstream of—the inlet port fitting 154, and it may also be fluidly coupled to a valve train carrier 105, so that it may receive fuel that leaks off from the fuel injectors (not shown) and provide it to the inlet port 155. The outlet port 171 is positioned downstream of the inlet port 155, the outlet port 171 being configured, for example, to distribute the fuel t o a fuel tank (not shown).
An inlet port fitting 172 may be positioned in a pump leak inlet port 177, wherein the inlet port fitting 172 may be a line nut that cooperates with the EGR cooler mount 110 so as to form an o-ring face seal connection. A tube 193 may be fluidly coupled to, and positioned downstream of, the inlet port fitting 172, and it may also be fluidly coupled to—and positioned downstream of—a high pressure fuel pump of the high pressure fuel system 109.
The leak off passage 182 is positioned fluidly between the inlet port 155 and the outlet port 171, and may be formed by a leak off passage tube 183. The leak off passage tube 183 may be made of steel and cast into position—using, for example, a lost foam casting process—so as to potentially eliminate machining operations, cycle times, and leak paths.
The EGR cooler mount 110 may comprise a rail leak off passage 167 and a rail leak inlet port 144, the rail leak inlet port 144 being configured to receive leak off fuel from a common fuel rail 114. The leak off passage 182 comprises a rail leak outlet port 160 that is positioned downstream of the rail leak inlet port 144. The rail leak off passage 167 extends fluidly between the rail leak inlet port 144 and the rail leak off outlet port 160.
A rail leak off fitting 145 may be positioned in the rail leak inlet port 144, and may be, for example, a line nut that cooperates with the EGR cooler mount 110 so as to form an o-ring face seal connection. As illustrated, the rail leak off passage 167 may be a cross drilled passage. A tube 194 may be fluidly coupled to—and positioned upstream of—the rail leak off fitting 145, so as to receive fuel that leaks off from the common fuel rail 114.
The EGR cooler mount 110 may comprise a fuel passage inlet port 146, a fuel passage outlet port 176, and a fuel supply passage 165. A fuel passage outlet fitting 175 may be positioned in the fuel passage outlet port 176, and the fuel passage outlet fitting 175 may be a line nut that cooperates with the EGR cooler mount 110 so as to form an o-ring face seal connection. A tube 195 may be fluidly coupled to, and positioned downstream of, the fuel passage outlet fitting 175.
A fuel passage inlet fitting 147 may be positioned in the fuel passage inlet port 146, and the fuel passage inlet fitting 147 may be a line nut that cooperates with the EGR cooler mount 110 so as to form an o-ring face seal connection. As shown, a tube 192 may be fluidly coupled to—and be positioned upstream of—the fuel passage inlet fitting 147. The fuel passage outlet port 176 may be positioned downstream of the fuel passage inlet port 146. The fuel passage inlet port 146 may be configured to receive fuel from, for example, a low pressure fuel system 108, and the fuel passage outlet port 176 may be configured to deliver fuel to, for example, a high pressure fuel system 109 that then delivers the fuel to be combusted in the engine 106.
The fuel supply passage 165 may be positioned fluidly between the fuel passage inlet port 146 and the fuel passage outlet port 176. As shown, the fuel supply passage 165 may be “L-shaped,” but it may take other shapes as appropriate in a given application. The fuel supply passage 165 may be made of steel and cast into position—using, for example, a lost foam casting process—so as to potentially eliminate machining operations, cycle times, and leak paths.
The fuel supply passage 165 may comprise a pressure sensor port 157 and a temperature sensor port 161, the pressure sensor port 157 and the temperature sensor port 161 being positioned, in the illustrated embodiment, in series relative to one another. A pressure sensor 159 may be positioned in the pressure sensor port 157, and a temperature sensor 162 may be positioned in the temperature sensor port 161. As shown, a cross drilled temperature sensor passage 166 may open into the temperature sensor port 161, and a cross drilled pressure sensor passage 168 may open into the pressure sensor port 157. The pressure sensor port 157 may be positioned downstream of the temperature sensor port 161, and the fuel passage outlet port 176, downstream of the pressure sensor port 157.
The EGR cooler mount 110 may further comprise a substantially vertical wall 129 and a substantially horizontal wall 131, so that the straps 119 may apply a clamp force about the EGR cooler 118, thereby forcing it towards both the substantially vertical wall 129 and the substantially horizontal wall 131. The substantially vertical wall 129 and the substantially horizontal wall 131 may form a mount edge 125. The pressure sensor port 157 and the temperature sensor port 161 may both be positioned in a sensor mount 116, the sensor mount 116 extending from the substantially horizontal wall 131. As illustrated, the fuel supply passage 165 may be positioned in a combination of the substantially horizontal wall 131 and the sensor mount 116, though it may be positioned anywhere in the EGR cooler mount 110, depending on the particular application.
The fuel supply passage 165 may comprise an air bypass outlet port 158, and the leak off passage 182 may comprise an air bypass inlet port 163. An air bypass passage 153 may be positioned fluidly between the air bypass outlet port 158 and the air bypass inlet port 163. The rail leak outlet port 160 may be positioned downstream of the air bypass inlet port 163. As illustrated, the air bypass outlet port 158 may be a drilled opening in the fuel supply passage 165, and the air bypass outlet port 158 and the air bypass inlet port 163 may be coaxially aligned, as a result of being part of the a cross drilled passage.
An air bleed check valve 156 may be configured to block communication (e.g., air and fuel), between the air bypass passage 153 and the leak off passage 182, when in a closed position, but configured to allow communication, between the same components, when in an open position. The air bleed check valve 156 may be open in a direction away from the fuel supply passage 165 and towards the leak off passage 182, or more specifically, the air bleed check valve 156 may be configured to open if there is any air upstream thereof in the fuel supply passage 165. Air may be present in the fuel supply passage 165 following assembly and/or maintenance to the power system 100.
The air bleed check valve 156 may be a check valve that, for example, comprises a ball 150 and a spring 152, the ball 150 being sandwiched between the spring 152 and the air bypass inlet port 163. Although the air bleed check valve 156 is shown as a ball check valve, in other embodiments, the air bleed check valve 156 may be—for example—a diaphragm check valve, a swing check valve, or a stop check valve. An outer diameter of the ball 150 may be greater than in inner diameter of the air bypass inlet port 163. In such an embodiment, the spring 152 and the ball 150 and the air bypass passage 153 may all be coaxially aligned relative to one another.
Although not shown, the air bleed check valve 156 may be positioned in the air bypass passage 153. In such an embodiment, the air bleed check valve 156 may be configured to block communication (e.g., air and fluid), between the fuel supply passage 165 and the leak off passage 182, when in a closed position, but configured to allow communication when in an opened position.
In the embodiment shown, the leak off passage 182 comprises first through sixth segments 184a-184f, and bends 185a-185e separate each of the segments 184a-184f. The first and second segments 184a, 184b may be positioned in the substantially vertical wall 129, while the third through sixth segments 184c-184f may be positioned in the substantially horizontal wall 131. The third segment 184c may overlap the mount edge 125. Further, the inlet port 155 and the air bypass inlet port 163 may be positioned in the first segment 184a; rail leak outlet port 160, in the third segment 184c; and the outlet port 171, in the sixth segment 184f.
Further, in the embodiment shown, the fuel supply passage 165 comprises first through third segments 188a-188c, and bends 189a, 189b may be positioned between each of the segments 188a-188c. The first segment 188a and the third segments 188c may be positioned in parallel with respect to one another and with the mount edge 125, while the second segment 188b may be positioned perpendicularly with respect to the first segment 188a and the third segment 188c and the mount edge 125. The second segment 188b and the third segments 188c may be positioned in the sensor mount 116. The fuel passage inlet port 146 may be positioned in the first segment 188a, and the pressure sensor port 157 and the temperature sensor port 161 and the fuel passage outlet port 176 are all positioned in the third segment 188c.
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present invention as defined by the appended claims.
