Abstract:
A power system, including a multi-cylinder air breathing, fuel consuming diesel engine having a manifold with a common inlet for distributing combustion air to a plurality of cylinders. A valve is positioned in the intake manifold to at least restrict air flow to a group of the cylinders of the engine less than the total number of cylinders so as to increase the load and increase the temperature of exhaust gas for facilitating regeneration of a particulate filter.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to internal combustion engines, and, more particularly, to systems for facilitating the regeneration of particulate filters used with such internal combustion engines. 
       BACKGROUND OF THE INVENTION 
       [0002]    For a number of years, the evermore stringent EPA limitations on products of combustion from internal combustion engines have given rise to the need for particulate filters filtering particles from an internal combustion engine&#39;s exhaust system. Although diesel power systems have employed particulate filters, known as diesel particulate filters (DPF) for a number of years, direct fuel injection for other types of internal combustion engines have also indicated the need for a particulate filter. Such particulate filters have filtration media for collecting particles on the filter media to prevent the particles from being discharged to the atmosphere. As with any filter, there is a finite capacity to the particles trapped by the filter and there exists a need for regeneration of the filter or burning off the particles. 
         [0003]    Generally, such regeneration requires an elevated temperature in the exhaust, either by the addition of hydrocarbon fuels or by other forms of temperature increase. Regardless of the specific mechanism to regenerate the filter, there have been a number of systems proposed for increasing the load on engines and, therefore, increasing the exhaust temperature upstream of the particulate filter. Such systems may involve manipulation of exhaust gasses by increased restriction or manipulation of flow through complex variable intake valve systems or variable turbine geometry systems. While these provide the increase in exhaust temperatures necessary, they do so at an increased cost and complexity in the engine system. 
         [0004]    What is needed, therefore, in the art is a simplified system for increasing exhaust gas temperatures for regeneration purposes. 
       SUMMARY 
       [0005]    The present invention includes, in one form, a power system with an air breathing, fuel consuming internal combustion engine having a plurality of cylinders and producing a rotary output and products of combustion. An intake manifold receives combustion air from a common inlet and it distributes the air to the cylinders for combustion. A fuel system delivers fuel at controlled rates to at least a group of cylinders less than the total number of cylinders for such engine. A particulate filter receives products of combustion from the engine with the particulate filter requiring periodic regeneration. A valve is positioned in the intake manifold to at least restrict combustion air flow to the group of cylinders, the fuel system at least reducing fuel flow substantially simultaneously with the reduction of airflow to the group of cylinders. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0007]      FIG. 1  shows a schematic drawing of a power system embodying the present invention. 
           [0008]      FIG. 2  shows the power system of  FIG. 1  with a first kind of valve, and 
           [0009]      FIG. 3  shows the power system of  FIG. 1  with a second kind of valve. 
       
    
    
       [0010]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0011]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a power system with a multi-cylinder internal combustion engine  12  having a plurality of cylinders  16  in which pistons (not shown) reciprocate to produce a rotary power output via a crank shaft  14 . The engine  12  receives air for combustion from an intake manifold  18  comprising inlets  20  for a first group of cylinders and inlets  22  for a second group of cylinders. As illustrated, the engine  12  has six cylinders and the group of cylinders fed by intake runners  20  and  22  is equal. However, it should be apparent to those skilled in the art that the number of cylinders within each group may be varied. 
         [0012]    The cylinders of engine  12  receive fuel, as will be described later, and produce combustion, which is delivered past exhaust valves (not shown) and exhaust manifold  26  and from there to the inlet  28  of the turbine  30  for a turbocharger  32 . The exhaust gasses thus passing from turbine  30  pass through turbine outlet  34  to an exhaust aftertreatment device  36 , which may be an oxidization catalyst or particulate filter or a combination of both and, from there, through an exhaust line  38  to the ambient. The exhaust aftertreatment device  36  does collect particles harmful to the environment and must be periodically regenerated or cleaned of the particles. 
         [0013]    The air for combustion enters the power system via intake line  40  through appropriate filtration devices and is delivered to the intake of compressor  42  connected to and driven by the turbine  30  by shaft  44 . Pressurized air from compressor  42  extends via line  46  to the inlet of an after cooler or intercooler  48  for reducing the temperature of the pressurized gas and, thus, the density of air and oxygen consumed by engine  12 . The after cooler or intercooler may be any one of a variety of coolers including air-to-air coolers relying on ambient air for cooling or an air-to-liquid cooler relying on engine coolant for particular applications. The air thus cooled enters intake line  24  leading to intake manifold  18 . 
         [0014]    The power system of  FIG. 1  includes exhaust gas recirculation or EGR and this is accomplished by a line  50  tapping into exhaust manifold  26  or some portion of the exhaust flow path and extending through a cooler  52 , which may be employed to decrease the temperature of exhaust gasses thus passed to the intake manifold and increasing efficiency of the engine  12 . Whether the exhaust gas is cooled or not, it is passed through an EGR valve  54 , which controls flow through a line  56  connected to inlet line leading to intake manifold  18 . 
         [0015]    Engine  12  has a fuel system indicated schematically by reference character  58 , which receives control inputs from engine parameter sensors and a primary input via line  60  or a plurality of lines from an electronic control unit  62  or ECU. The ECU  62  preferably provides control of EGR valve through line  64  to control flow of exhaust gasses from the products of combustion of engine  12  to the intake manifold  18 . 
         [0016]    In accordance with the invention, a valve  66  is provided within intake manifold  18  and is controlled by ECU  62  via line  68 . Valve  66  is established in flow relation between the intake runners  20  and  22  within intake manifold  18  to selectively at least restrict and also to block intake air flow to cylinders  16  fed by runners  22 . Substantially simultaneously with the blockage or restriction of flow to the cylinder group fed by runners  22 , the fuel flow to that group of cylinders by fuel system  58  is reduced or terminated. This, in effect, eliminates the group of cylinders fed by runners  22  to take away their power generating capacity and increase the load on the remaining cylinders both from overall engine parasitic loads and from the additional parasitic loads produced by the inactive group of cylinders. 
         [0017]    The valve  62  may take several forms, some of which are illustrated in  FIGS. 2 and 3 .  FIG. 2  shows the valve  66  in the form of a butterfly valve  70  mounted on a central pivoting shaft  72  and pivotable via connection  68  to ECU  62  within a semi-hemispheric chamber  74  to either present substantially no restriction to flow in a horizontal position, as viewed in  FIG. 2 , or substantially blocking flow in a position that is vertical, as viewed in  FIG. 2  and illustrated in dashed lines. Butterfly valves have progressed so that, with improved sealing edges, a substantial reduction of flow may be accomplished to eliminate flow to the group of cylinders fed by runners  22  and thus increase the load on the engine  12 . 
         [0018]      FIG. 3  shows another form of a valve  66 , in this case, a guillotine valve  80  in the form of a plate that slides in the inner surfaces  82  of housing  84  extending from intake manifold  18 . The plate  80  is mounted on and guided by a shaft  86  that is connectable via connection  68  so as to displace plate  80  from a position in which there is substantially no restriction to flow through intake manifold and another position illustrated in dashed lines in which plate  80  seats in recess  88  to substantially block flow through intake manifold  18 . Although not shown, the connections  68  for both the valve  70  and  80  typically include an actuator (not shown) controllable by ECU  62 . 
         [0019]    Using both forms of valves, and others as apparent to those skilled in the art, the flow to the second set of cylinders fed by runners  22  is varied to the point where combustion air flow may be substantially blocked along with a substantially simultaneous termination of fuel flow to the cylinders  16 . This effectively imposes an increased load on the engine, especially during part throttle conditions in which there is insufficient natural load on the engine  12  to raise exhaust temperatures to the point of facilitating regeneration of particulate filter  36 . In addition, the valves provide a simplified way of increasing exhaust temperatures during light load conditions by partially blocking flow, thus improving operation of various exhaust aftertreatment devices. 
         [0020]    While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.