Abstract:
The present invention is an exhaust mode selector system which is able to control an exhaust system, as the exhaust system changes to accommodate various driving conditions. The exhaust system includes various exhaust flow paths to configure the exhaust system for operating in a highway mode, used for when the vehicle is operating on the highway, and a city mode, used for when the vehicle is operating under city driving conditions. A controller is able to position one or more valves to various configurations to transition between city driving and highway driving. Each of the valves being configurable provides for optimization of the balance between required power, fuel economy, and noise reduction.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to an exhaust mode selector system which is operable for changing between multiple modes of operation to accommodate for different modes of driving. 
       BACKGROUND OF THE INVENTION 
       [0002]    Exhaust systems are generally known, and are used not only for directing the exhaust gas from an engine away from a vehicle, but are also used to control various emissions of an engine, and to help optimize fuel economy. 
         [0003]    Many attempts have been made to improve the functionality of exhaust systems. However, because of the wide range of driving conditions, such as highway driving and city driving, exhaust systems are not always suitable for optimizing fuel economy, reducing emissions, and maximizing engine power. More specifically, an exhaust system which is optimized for conditions such as highway driving, which involve a more consistent engine speed, fewer stops, and increased fuel economy, may be different than an exhaust system which is optimized for city driving conditions, which have less consistent engine speed, many stops, and decreased fuel economy. 
         [0004]    Accordingly, there exists a need for an exhaust system which is adaptable for various types of driving conditions. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is an exhaust mode selector system which is able to control an exhaust system, as the exhaust system changes to accommodate various driving conditions. The exhaust system includes a highway mode, used for when the vehicle is operating on the highway, and a city mode, used for when the vehicle is operating under city driving conditions. 
         [0006]    In one embodiment, the present invention is an exhaust system having multiple modes of operation and multiple flow paths. An engine generates exhaust gas that is directed along a first exhaust flow path, or a second exhaust flow path. Also included is a first vehicle emissions control device, such as a catalytic converter or a diesel particulate filter (DPF), which is in fluid communication with the engine, and receives exhaust gas from the engine. A first cutout has a first valve, a primary inlet connected to and in fluid communication with the first vehicle emissions control device, a first outlet, and a second outlet. 
         [0007]    A second vehicle emissions control device, such as a second catalytic converter, or a second DPF, is in fluid communication with the first cutout. The present invention also includes a second cutout having a second valve, a first inlet, a second inlet, and a primary outlet. The second cutout is connected to and in fluid communication with the first cutout and the second vehicle emission control device. A controller controls the operation of the first valve and the second valve. A resonator is in fluid communication with the primary outlet of the second cutout. 
         [0008]    In an embodiment, the exhaust system not only includes a first catalytic converter and a second catalytic converter used as the respective first and second vehicle emissions control devices, but also includes a first muffler in fluid communication with the first outlet of the first cutout and the first inlet of the second cutout, and a second muffler in fluid communication with the second catalytic converter and the second inlet of the second cutout. 
         [0009]    The controller positions the first valve and the second valve to direct the exhaust gas from the first catalytic converter into the primary inlet and through the first outlet of the first cutout, through the first muffler, and into the first inlet of the second cutout, out of the primary outlet, and through the resonator when the exhaust system is operating under highway driving conditions. The controller is also able to position the first valve and the second valve to direct the exhaust gas from the first catalytic converter into the primary inlet and through the second outlet of the first cutout, through the second catalytic converter, through the second muffler, and into the second inlet of the second cutout, out of the primary outlet, and through the resonator when the exhaust system is operating under city driving conditions. 
         [0010]    In another embodiment, the first vehicle emissions control device is a first diesel particulate filter, and the second vehicle emissions control device is a second diesel particulate filter. A first Selective Catalytic Reduction (SCR) catalyst is in fluid communication with the first outlet of the first cutout and the first inlet of the second cutout, and a second SCR catalyst in fluid communication with the second DPF and the second inlet of the second cutout. 
         [0011]    In this embodiment, the controller positions the first valve and the second valve to direct the exhaust gas from the first diesel particulate filter into the primary inlet and through the first outlet of the first cutout, through the first SCR catalyst, and into the first inlet of the second cutout, out of the primary outlet, and through the resonator when the exhaust system is operating under highway driving conditions. The controller also positions the first valve and the second valve to direct the exhaust gas from the first diesel particulate filter into the primary inlet and through the second outlet of the first cutout, through the second diesel particulate filter, through the second SCR catalyst, and into the second inlet of the second cutout, out of the primary outlet, and through the resonator when the exhaust system is operating under city driving conditions. 
         [0012]    This embodiment also includes a diesel exhaust fluid (DEF) tank in fluid communication with the exhaust system upstream of the first SCR catalyst and in fluid communication with the exhaust system upstream of the second SCR catalyst, an SCR valve in fluid communication with the DEF tank, a first fluid delivery pipe in fluid communication with the SCR valve, and a second fluid delivery pipe in fluid communication with the SCR valve. 
         [0013]    The SCR valve transfers diesel exhaust fluid through the first fluid delivery pipe to a location upstream of the first SCR catalyst when the exhaust system is operating under highway driving conditions, and transfers diesel exhaust fluid through the second fluid delivery pipe to a location upstream of the second SCR catalyst when the exhaust system is operating under city driving conditions. 
         [0014]    With each embodiment, the controller is able to position each of the valves to other various configurations to transition between city driving conditions and highway driving conditions. Each of the valves being configurable provides for optimization of the balance between required power, fuel economy, and noise reduction. 
         [0015]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0017]      FIG. 1  is a diagram of an exhaust mode selector system, according to embodiments of the present invention; 
           [0018]      FIG. 2  is a diagram of an exhaust mode selector system operating in a first mode of operation, according to embodiments of the present invention; 
           [0019]      FIG. 3  is a diagram of an exhaust mode selector system operating in a second mode of operation, according to embodiments of the present invention; 
           [0020]      FIG. 4  is a diagram of an alternate embodiment of an exhaust mode selector system, according to embodiments of the present invention; and 
           [0021]      FIG. 5  is a rear view of a vehicle which includes an exhaust mode selector system, according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0023]    An exhaust system, having multiple exhaust flow paths is shown generally in the Figures schematically at  10 . The exhaust system  10  includes an exhaust pipe  12  connected to an engine  14  used to propel a vehicle. The exhaust pipe  12  is connected to a first catalytic converter  16 , and the first catalytic converter  16  is connected to a first cutout  18 . The first cutout  18  is an inlet cutout  18 , and includes a primary inlet  20 , and two outlets, a first outlet  22  and a second outlet  24 . The first outlet  22  is connected to a first exhaust delivery pipe  26 , and the first exhaust delivery pipe  26  is connected to a highway muffler  28 . The highway muffler  28  is connected to a second exhaust delivery pipe  30 , and the second exhaust delivery pipe  30  is connected to first inlet  32  of a second cutout  34 . 
         [0024]    The second outlet  24  is connected to a first exhaust transfer pipe  36 , and the first exhaust transfer pipe  36  is connected to a second catalytic converter  38 . The second catalytic converter  38  is connected to an intermediate exhaust transfer pipe  40 , and the intermediate exhaust transfer pipe  40  is connected to a city muffler  42 . The city muffler  42  in turn is connected to a second exhaust transfer pipe  44 , and the second exhaust transfer pipe  44  is connected to a second inlet  46  of the second cutout  34 . 
         [0025]    The second cutout  34  is an outlet cutout  34 , and also includes a primary outlet  48  which is connected to a resonator pipe  50 , and the resonator pipe  50  is connected to a resonator  52 . 
         [0026]    Control over the flow of exhaust gas through each of the cutouts  18 , 34  is achieved through the use of a controller  54 . Each of the cutouts  18 , 34  includes a valve, the operation of which is controlled by the controller  54 . More specifically, there is a first valve  56  which is part of the first cutout  18 , and a second valve  58  which is part of the second cutout  34 . 
         [0027]    During operation of the system  10 , if the vehicle is driving on a highway, or other type of road where driving conditions include relatively higher speeds (such as fifty-five miles per hour or greater) with few stops, the controller  54  commands each of the valves  56 , 58  to move to a first position. The first position of the first valve  56  prevents exhaust flow from exiting the second outlet  24 , such that all of the exhaust gas flowing into the inlet  20  flows out of the first outlet  22 . The first position of the second valve  58  allows for exhaust gas entering the first inlet  32  to pass through the second cutout  34  and exit the primary outlet  48 , and prevents exhaust flow entering the second inlet  46  from exiting the primary outlet  48 . 
         [0028]    When both of the valves  56 , 58  are in the first position, the exhaust gases produced by the engine  14  flow through the exhaust pipe  12 , the first catalytic converter  16 , the first cutout  18 , the first exhaust delivery pipe  26 , the highway muffler  28 , the second exhaust delivery pipe  30 , the second cutout  34 , the resonator pipe  50 , and the resonator  52 . The flow through the first catalytic converter  16 , the first cutout  18 , the first exhaust delivery pipe  26 , the highway muffler  28 , the second exhaust delivery pipe  30 , and the second cutout  34  creates a first exhaust flow path. When the exhaust system  10  is in this first condition, or first mode of operation, the exhaust flow is least restrictive, allowing for less backpressure, and allows for more of the power produced by the engine to be used to propel the vehicle. 
         [0029]    If the vehicle is driving at lower speeds and is experiencing frequent stops (or “stop and go” driving) such as when the vehicle is driving in the city, the controller  54  commands each of the valves  56 , 58  to move to a second position. The second position of the first valve  56  prevents exhaust flow from exiting the first outlet  22 , and forces all of the exhaust gas to flow out of the second outlet  24 . The second position of the second valve  58  allows for exhaust gas entering the second inlet  46  to pass through the second cutout  34  and exit the primary outlet, and prevents exhaust flow entering the first inlet  32  from exiting the primary outlet  48 . 
         [0030]    When both of the valves  56 , 58  are in the second position, the exhaust gases from the engine  14  flow through the exhaust pipe  12 , the first catalytic converter  16 , the first cutout  18 , the first exhaust transfer pipe  36 , the second catalytic converter  38 , the intermediate exhaust transfer pipe  40 , the city muffler  42 , the second exhaust transfer pipe  44 , the second cutout  34 , the resonator pipe  50 , and the resonator  52 . The flow through the first catalytic converter  16 , the first cutout  18 , the first exhaust transfer pipe  36 , the second catalytic converter  38 , the intermediate exhaust transfer pipe  40 , the city muffler  42 , the second exhaust transfer pipe  44 , and the second cutout  34  creates a second exhaust flow path. When the exhaust system  10  is in this second condition, or second mode of operation, the exhaust flow is more restrictive because the exhaust gas passes through both catalytic converters  16 , 38 , and the city muffler  42  is larger than the highway muffler  28 . This mode provides for reduced emissions and reduced noise, and although this mode also reduces the performance ability of the engine  14 , maximizing performance during city driving is not necessary, and therefore the reduction in available power is not considered a significant drawback in light of the improved efficiency and noise reduction. 
         [0031]    In addition to the valves  56 , 58  being placed in their respective first positions and the second positions, the valves  56 , 58  are able to be placed into any position between the first positions and the second positions, allowing for the exhaust system  10  to transition between highway driving and city driving. The controller  54  controls the positioning of each of the valves  56 , 58 , between the various positions, controlling the flow of exhaust gas between the first exhaust flow path and the second exhaust flow path. The controller  54  may position the valves  56 , 58  to direct a portion of the exhaust gas through the first exhaust flow path, and another portion of the exhaust gas through the second exhaust flow path during the transition between city driving and highway driving. How the flow of exhaust gas is distributed between the first exhaust flow path and the second exhaust flow path is based upon a number of factors which include, but are not limited to, the speed of the vehicle, the amount of stop and go driving, fuel economy, noise control, emissions control, and the like. 
         [0032]    An alternate embodiment of the invention is shown in  FIGS. 4 and 5 , with like numbers referring to like elements. The embodiment shown in  FIGS. 4 and 5  is for use with a commercial vehicle, shown generally at  78 , which has different emissions resulting from the use of a different type of fuel, such as diesel fuel. More specifically, the embodiment shown in  FIGS. 4 and 5  incorporates the process of Selective Catalytic Reduction (SCR). In this embodiment, instead of using catalytic converters  16 , 38 , a first diesel particulate filter  60  is connected to the exhaust pipe  12  and the primary inlet  20  of the first cutout  18 , and a second diesel particulate filter  62  is connected to the first exhaust transfer pipe  36  and the intermediate exhaust transfer pipe  40 . Furthermore, instead of the mufflers  28 , 42 , the system  10  includes a first SCR catalyst  64  connected to the first exhaust delivery pipe  26  and the second exhaust delivery pipe  30 , and a second SCR catalyst  66  connected to the intermediate exhaust transfer pipe  40  and the second exhaust transfer pipe  44 . 
         [0033]    Also included in the embodiment shown in  FIGS. 4 and 5  is a Diesel Exhaust Fluid (DEF) tank  68  having diesel exhaust fluid. The DEF tank  68  includes an outlet pipe  70 , an SCR valve  72 , a first delivery pipe  74  and a second delivery pipe  76 . 
         [0034]    In operation, the engine  14  (which in this embodiment is a diesel engine) produces exhaust emissions, which flow through the exhaust pipe  12  and into the first diesel particulate filter  60 . The exhaust gas then flows into the first cutout  18 . Both valves  56 , 58  in each of the cutouts  18 , 34  are able to change between a first position and a second position. 
         [0035]    As with the previous embodiment, the first position of the first valve  56  prevents exhaust flow from exiting the second outlet  24 , such that all of the exhaust gas flowing into the inlet  20  flows out of the first outlet  22 . Furthermore, the first position of the second valve  58  allows for exhaust gas entering the first inlet  32  to pass through the second cutout  34  and exit the primary outlet  48 , and prevents exhaust flow entering the second inlet  46  from exiting the primary outlet  48 . When the valves  56 , 58  of both the cutouts  18 , 34  are in their respective first positions, the exhaust gases produced by the engine  14  flow through the exhaust pipe  12 , the first diesel particulate filter  60 , the first cutout  18 , the first exhaust delivery pipe  26 , the highway SCR catalyst  64 , the second exhaust delivery pipe  30 , the second cutout  34 , the resonator pipe  50 , and the resonator  52 . The flow of exhaust gas through the first diesel particulate filter  60 , the first cutout  18 , the first exhaust delivery pipe  26 , the highway SCR catalyst  64 , the second exhaust delivery pipe  30 , and the second cutout  34  creates a first exhaust flow path. 
         [0036]    When the exhaust system  10  is in this condition, or mode, the exhaust flow is least restrictive, allowing for less backpressure, and more power produced by the engine to be used to propel the vehicle. 
         [0037]    When the vehicle is operating under city driving conditions, the controller  54  commands the valves  56 , 58  to move to their respective second positions. When the valves  56 , 58  are both in their respective second positions, the first valve  56  prevents exhaust gas from exiting the first outlet  22 , and forces all of the exhaust gas to flow out of the second outlet  24 . The second position of the second valve  58  allows for exhaust gas entering the second inlet  46  to pass through the second cutout  34  and exit the primary outlet, and prevents any exhaust gas entering the first inlet  32  from exiting the primary outlet  48 . 
         [0038]    When both of the valves  56 , 58  are in their respective second positions, the exhaust gases from the engine  14  flow through the exhaust pipe  12 , the first diesel particulate filter  60 , the first cutout  18 , the first exhaust transfer pipe  36 , the second diesel particulate filter  62 , the intermediate exhaust transfer pipe  40 , the city SCR catalyst  66 , the second exhaust transfer pipe  44 , the second cutout  34 , the resonator pipe  50 , and the resonator  52 . The flow of exhaust gas through the first diesel particulate filter  60 , the first cutout  18 , the first exhaust transfer pipe  36 , the second diesel particulate filter  62 , the intermediate exhaust transfer pipe  40 , the city SCR catalyst  66 , the second exhaust transfer pipe  44 , and the second cutout  34  creates a second exhaust flow path. When the exhaust system  10  is in this second condition, or second mode of operation, the exhaust flow is more restrictive because the exhaust gas passes through both diesel particulate filters  60 , 62 , and the city SCR catalyst  66  is larger than the highway SCR catalyst  64 . This mode of operation provides for reduced emissions and reduced noise, and although this mode also reduces the performance ability of the engine  14 , maximizing performance during city driving is not necessary, and therefore the reduction in available power is not considered a significant drawback in light of the improved efficiency and noise reduction. 
         [0039]    During either mode of operation, the diesel exhaust fluid in the DEF tank  68  may be used to reduce the emission of oxides of nitrogen. The valve  72  is controlled by the controller  54 , and is used to inject diesel exhaust fluid from the outlet pipe  70  through the first delivery pipe  74  and into the first exhaust delivery pipe  26 , or inject diesel exhaust fluid from the outlet pipe  70  through the second delivery pipe  76  and into the first exhaust transfer pipe  36 . When the diesel exhaust fluid is injected to either the first exhaust delivery pipe  26  or the first exhaust transfer pipe  36 , the diesel exhaust fluid mixes with the exhaust gas, and when combined with the either of the SCR catalysts  64 , 66 , emissions of oxides of nitrogen are reduced. The DEF is injected into the first exhaust flow path, more specifically the first exhaust delivery pipe  26  when operating in the first mode of operation, and injected into the second exhaust flow path, more specifically the first exhaust transfer pipe  36 , when operating in the second mode of operation. 
         [0040]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.