Abstract:
Exhaust systems and passenger service vehicles, for example, buses are used together. The exhaust system can be arranged, in use, to be above an engine compartment. The exhaust system includes a first filter and a second filter, each filter having an inlet and an outlet. The inlets are inline with the respective first and second filters, and the outlets are transversely arranged with reference to the respective filters. Vehicles may have an overall length of about 35 feet or less and have an unladen weight of around 25,000 lbs or less.

Description:
REFERENCE TO RELATED APPLICATION 
     The application claims priority to United Kingdom Application No. 1304945.7 filed on Mar. 18, 2013. 
     TECHNICAL FIELD 
     The invention relates to the field of vehicles, such as passenger service vehicles and, for example, buses. In particular, but not exclusively, the invention relates to an exhaust system for a passenger vehicle. Further, the invention relates to, but is not limited to, a chassis for vehicles such as passenger service vehicles, as well as associated apparatus, structures, vehicles and methods. 
     BACKGROUND 
     Modern passenger service vehicles are increasingly required to provide efficiencies for vehicle operators in terms of greater number of passengers carried and increased fuel efficiency. The physical dimensions of a passenger service vehicle have a significant impact on overall vehicle efficiency. 
     In addition, certain jurisdictions have particular requirements for passenger vehicle dimensions, for example, size, weight, clearance and front and rear overhang. 
     SUMMARY 
     Generally, aspects of the invention provide apparatus configured to save space within a passenger service vehicle, such as a bus. 
     In some examples, there is provided a filter for an exhaust system of a passenger service vehicle. The filter includes an inlet and an outlet. The outlet may be substantially transverse to the inlet. The outlet may be substantially at right-angles to the inlet. The inlet may be inline with the filter. The outlet may be transversely arranged with reference to the filter. 
     The filter may include a particulate filter. The filter may include a catalytic converter. The filter may include a selective catalytic reduction filter. 
     In some examples, there is provided a passenger service vehicle exhaust system including a filter as described above. 
     In some examples, there is provided an exhaust system arranged to be on top of the engine compartment of a passenger service vehicle. The exhaust system may include a filter as described above. 
     There may also be provided a passenger service vehicle including an exhaust system as described above. The vehicle may be a bus. 
     The vehicle may have an overall length of about 35 feet or less. For example, the vehicle may have an overall length of between 25 feet and 35 feet. In some examples, the vehicle may have an overall length of approximately 35 feet. Such a vehicle may be configured to provide at least 35 passenger seats. Such a vehicle may have an unladen weight of around 25,000 lbs, or less (e.g., roughly 20,000 lbs, or even less). 
     In other examples, the vehicle may have an overall length of approximately 30 feet. Such a vehicle may be configured to provide at least 27 passenger seats. Such a vehicle may have an unladen weight of around 22,000 lbs or less (e.g, 18,000 lbs, or even less). 
     The vehicle may have a front overhang (i.e., a distance from the front of the vehicle to the center of a front axle) of around 250 cm, 230 cm or less (e.g, 226 cm). The vehicle may have a rear overhang (i.e., a distance from the rear of the vehicle to the center of a rear axle) of around 300 cm, 275 cm or less (e.g, 271 cm). 
     The vehicle may include a longitudinally mounted engine (e.g, a six cylinder longitudinally mounted engine). Such an engine may be compliant with, for example, environmental protection agency requirements. The vehicle may be a single-deck vehicle. The vehicle may include at least two passenger doors. The vehicle may include a vertical exit exhaust. The vehicle may include an air conditioning system. The conditions system may be mounted on the external of the vehicle. The conditioning system may be provided in a middle region of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are described with reference to the accompanying drawings, in which: 
         FIG. 1  is an isometric view of an exhaust system; 
         FIG. 2 a    is a schematic representation of the layout of a bus; and 
         FIG. 2 b    is a side elevation of a bus. 
     
    
    
     DETAILED DESCRIPTION 
     Generally disclosed herein is a filter for use in an exhaust system of a passenger service vehicle. Filters disclosed herein are configured to save space within a passenger service vehicle. Also disclosed herein are passenger service vehicle exhaust systems including the filter(s) and passenger service vehicles including the exhaust system(s). It is noted that the apparatus disclosed particularly relate to buses. 
       FIG. 1  shows a passenger service vehicle exhaust system  100 . Table 1 below provides a list of the features of the exhaust system  100  to augment the description given herein. The item numbers of the features listed in Table 1 are referenced by the circled reference numerals provided in  FIG. 1 . 
     The exhaust system  100  has an engine fitment  102  for fitting the exhaust system  100  to an engine (not shown). The engine fitment  102  is configured to be fitted to an exhaust outlet of an engine. Various apparatus may be employed to secure the engine fitment  102  to an engine, as will be understood by a skilled person. 
     The engine fitment is connected to a first section of exhaust pipe  104 . The first section of the exhaust pipe  104  extends from the engine fitment and includes a substantially right-angled bend. Therefore, the first section of exhaust pipe  104  is configured to carry exhaust fumes transversely away from the engine fitment  102 . 
     The first section of the exhaust pipe  104  is connected to a length of flexible tubing  106 . The flexible tubing  106  has an internal diameter configured such that the outer diameter of the first section of exhaust pipe  104  may be fitted inside the flexible tubing  106 . The flexible tubing  106  may have an internal diameter greater than or equal to an outer diameter of the first section of exhaust pipe  104 . Alternatively, the flexible tubing  106  may be elastically deformable such that it may be stretched over the first section of exhaust pipe  104 . The flexible tubing  106  is connected at an engine end to the first section of exhaust pipe  104  by feeding a portion of the first section of exhaust pipe  104  partially into the flexible tubing  106  and securing the two together using a clip  108 . The flexible tubing  106  is configured to absorb motion of the engine, to which the engine fitment  102  is connected, such that the motion is not transferred to the remainder of the exhaust system  100 . 
     
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 ITEM NO 
                 PART NO 
                 DESCRIPTION 
                 QTY 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 29 
                 453714 
                 WA; EXHAUST STACK 
                 1 
               
               
                 28 
                 611005-7 
                 TEE BOLT HOSE CLIP 
                 1 
               
               
                 27 
                 661331 
                 CLAMP-4″ MARMON V 
                 2 
               
               
                 26 
                 661327 
                 GASKET; 4″ MARMON 2 mm 
                 2 
               
               
                 25 
                 454227 
                 WA; BRKT DOWNPIPE 
                 1 
               
               
                 24 
                 MCN-508P 
                 NUT FULL S/L MS 
                 10 
               
               
                 23 
                 MCB-108-55P 
                 BOLT M8 × 55 
                 10 
               
               
                 22 
                 453869 
                 WA; DPF MTG SS 
                 2 
               
               
                 21 
                 441944 
                 WASHER M8 LARGE DIA 
                 10 
               
               
                 20 
                 453866 
                 WA; SCR MTG SS 
                 2 
               
               
                 19 
                 441945 
                 TUBE SPACER EXHST MTG 
                 10 
               
               
                 18 
                 661146 
                 MOUNT AV - HIGH TEMP 
                 20 
               
               
                 17 
                 662934 
                 CLAMP DPF 
                 2 
               
               
                 16 
                 662152 
                 CLIP EXHAUST 
                 2 
               
               
                 15 
                 662118 
                 CLAMP 5″ STRAIGHT 
                 2 
               
               
                 14 
                 662114 
                 CLAMP 4″ STRAIGHT 
                 1 
               
               
                 13 
                 662120 
                 CLAMP 4″ SPHERICAL 
                 1 
               
               
                 12 
                 662119 
                 GASKET 5″ STRAIGHT 
                 2 
               
               
                 11 
                 662115 
                 GASKET 4″ STRAIGHT 
                 1 
               
               
                 10 
                 453705 
                 WA; EXHAUST TURBO OUT 
                 1 
               
               
                 9 
                 662121 
                 GASKET 4″ SPHERICAL 
                 1 
               
               
                 8 
                 661323 
                 FLEX EXHAUST 4″ 
                 1 
               
               
                 7 
                 453706 
                 WA; EXHAUST DPF IN 
                 1 
               
               
                 6 
                 661976 
                 GASKET, EXHAUST 
                 1 
               
               
                 5 
                 661409 
                 CLAMP - 3½″ MARMON WIDE 
                 1 
               
               
                 4 
                 662959 
                 DPF - EPA 2013 
                 1 
               
               
                 3 
                 662960 
                 ELBOW DPF TO SCR 
                 1 
               
               
                 2 
                 662961 
                 SCR - EPA 2013 
                 1 
               
               
                 1 
                 862979 
                 DECOMPOSITION REACTOR 
                 1 
               
               
                   
               
             
          
         
       
     
     The exhaust system generally runs from an inlet at an engine end to an outlet at an exhaust end. Therefore, the term “engine end” refers to an end of a feature closest to the engine along the path of the system  100 . Accordingly, the term “exhaust end” refers to an end of a feature closest to the exhaust outlet along the path of the system  100 . 
     A second section of exhaust pipe  110  is connected to the flexible tubing  106 . The second section of the exhaust pipe  110  is connected to an exhaust end of the flexible tubing  106 . The second section of the exhaust pipe  110  includes a first substantially right-angled bend  112 . 
     The first bend  112  is configured to alter the direction of the exhaust system to be substantially vertical when the exhaust system  100  is fitted to a passenger service vehicle. This allows the exhaust system  100  to fit within the exhaust compartment of a bus, or other passenger service vehicle. 
     Stacking the exhaust system  100  in a vertical direction means that the length of a bus can be reduced. A central portion  114  of the second section of exhaust pipe  110  extends away from the first bend  112 . The central portion  114  may therefore extend vertically. A fixing bracket  116  extends from the central portion  114  and is configured to secure the exhaust system  100  to the vehicle frame. 
     At an exhaust end of the central portion  114  is a second substantially right-angled bend  118  in the second section of exhaust pipe  110 . The second bend  118  is configured to carry exhaust gases along a horizontal path within a passenger service vehicle. 
     A first filter  120  is connected to an exhaust end of the second section of exhaust pipe  110 . The first filter  120  is a particulate filter. The exhaust end of the second section of exhaust pipe  110  is connected to an inlet  122  of the first filter  120  using a clip, as explained above. 
     The first filter  120  is generally cylindrical. The inlet  122  is positioned centrally in a first face  124  of the cylindrical first filter  120  at an engine end of the filter  120 . Therefore, the inlet  122  is inline in that it is in the same direction as the direction of flow of exhaust gas through the first filter  120 . When the exhaust system  100  is fitted to a vehicle, the inlet  122  is substantially horizontal. 
     An outlet  126  of the filter  120  is transverse to the inlet  122 . The outlet  126  is substantially at right angles to the inlet  122 . Further, the outlet  126  is transverse to the line of the filter  120  in that it extends in a direction transverse to the direction of flow of exhaust gas through the first filter  120 . As a result, the outlet  126  extends in a vertical direction when the exhaust system  100  is fitted to a vehicle. The outlet  126  is generally cylindrical and is positioned at an exhaust end of the cylindrical filter  120 . The outlet  126  overlaps the end of the filter  120  such that a part of a second face  128  of the filter  120  is rounded to correspond to a part of a cylindrical wall of the outlet  126 . This can be seen more clearly on the second filter  142 , which is discussed below. 
     The first filter  120  includes a plurality of fixing brackets  130 ,  132  configured to secure the first filter  120  to a vehicle frame. 
     The outlet  126  of the first filter  120  is connected to a third section of an exhaust pipe  134 . An engine end of the third section of the exhaust pipe  134  is connected to the outlet  126  of the first filter using a clip, as explained above. The third section of the exhaust pipe  134  includes a substantially right-angled bend  136 . Therefore, the third section of the exhaust pipe  134  is configured to fold the path of the exhaust system  100  back on itself. That is, the path of the exhaust system  100  returns in an opposite direction to the direction of flow of exhaust gas through the first filter  120 . 
     A decomposition reactor  138  is connected to an exhaust end of the third section of the exhaust pipe  134 . The decomposition reactor  138  includes an injection inlet  140  configured to allow diesel exhaust fluid to be injected into the exhaust system  100 . The diesel exhaust fluid may be an aqueous urea solution for use in selective catalytic reduction for lowering the nitrogen oxide concentration in diesel exhaust emissions. Other fluids suitable for selective catalytic reduction, such as anhydrous ammonia or aqueous ammonia, may be used. 
     A second filter  142  is a selective catalytic reduction filter and is connected to an exhaust end of the decomposition reactor  138 . The exhaust end of the decomposition reactor  138  is connected to an inlet  144  of the second filter  142  using a clip, as explained above. 
     The second filter  142  is generally cylindrical. The inlet  144  is positioned centrally in a first face  146  of the cylindrical second filter  142  at an engine end of the filter  142 . Therefore, the inlet  144  is inline in that it is in the same direction as the direction of flow of exhaust gas through the second filter  142 . When the exhaust system  100  is fitted to a vehicle, the inlet  144  is substantially horizontal. 
     An outlet  148  of the filter  142  is transverse to the inlet  144 . The outlet  148  is substantially at right angles to the inlet  144 . Further, the outlet  148  is transverse to the line of the filter  142  in that it extends in a direction transverse to the direction of flow of exhaust gas through the second filter  142 . As a result, the outlet  148  extends in a vertical direction when the exhaust system  100  is fitted to a vehicle. The outlet  148  is generally cylindrical and is positioned at an exhaust end of the cylindrical second filter  142 . The outlet  148  overlaps the exhaust end of the filter  142  such that a part of a second face  150  of the filter  142  is rounded to correspond to a part of a cylindrical wall of the outlet  148 . 
     The second filter  142  includes a plurality of fixing brackets  152 ,  154  configured to secure the filter  142  to a vehicle frame. 
     The outlet  148  of the second filter  142  is connected to a fourth section of an exhaust pipe  156 , which passes exhaust gases through an exhaust system outlet  158 . The exhaust system outlet  158  includes a silencer  160 . 
     In use, exhaust gases are emitted from an engine and into the engine fitment  102 . The gases are passed through the first section of exhaust pipe  104 , the flexible tubing  106  and the second section of exhaust pipe  110  and into the first filter  120 . The first filter  120  removes particulate from the exhaust gases, which then pass through the third section of exhaust pipe  134  and into the decomposition reactor  138 . Diesel exhaust fluid is injected into the exhaust gases through the injection inlet  140 , and the second filter  142  undertakes selective catalytic reduction before the exhaust gases are emitted from the exhaust system outlet  158  via the fourth section of exhaust pipe  156 . 
       FIG. 2 a    shows the arrangement of certain elements of a bus  200  within a vehicle frame.  FIG. 2 b    shows a side elevation of a bus including the exhaust system  100 . 
     Referring to  FIG. 2 a   , an engine compartment  202  may be generally defined and is configured to hold an engine of the bus  200 . Further, an exhaust system compartment  204  can be generally defined and is configured to hold the exhaust system  100 . It can be seen from  FIG. 2 a    that stacking the exhaust system  100  in the vertical manner shown in  FIG. 1  allows the length of the bus  200  to be reduced. 
     The skilled person will be able to envision further embodiments of the invention without departing from the scope of the invention as disclosed herein. 
     Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.