Abstract:
An improved T fitting results in a more uniform flow of fumes from an engine crankcase. The T fitting combines flows from an air filter and a hose connected to the engine crankcase, into coaxial paths, and then combines the flows into a combined flow. The combined flow is drawn into an intake manifold by manifold vacuum. The combining of the flows through the coaxial paths results in a more uniform flow of fumes from the crankcase.

Description:
The present application is a Continuation in Part of U.S. patent application Ser. No. 11/781,826 filed Jul. 23, 2007, which is a Continuation in Part of U.S. patent application Ser. No. 11/330,466 filed Jan. 12, 2006, which applications are incorporated in their entirely herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to reducing emissions from internal combustion engines and in particular to an improved T fitting for a Positive Crankcase Ventilation (PCV) system to facilitate a flow of crankcase fumes from the crankcase and into an engine air intake. 
     Diesel engines are commonly used in commercial applications such as trucks and stationary engines. These engines typically have much higher compression ratios than gasoline engines, and as a result, a substantial amount of diesel blow-by escapes past the piston rings. Unlike gasoline engines which use a simple crankcase ventilation system, the diesel blow-by is generally vented to the outside, and presents a source of unpleasant fumes. Diesel engines typically can not simply vent the crankcase to the engine intake, because of the presence of the diesel blow-by includes components which are likely to degrade diesel engine performance. 
     U.S. patent application Ser. No. 11/330,466 for “HYDROGEN AUGMENTED DIESEL CRANKCASE VENTILATION,” a parent of the present application, discloses a system combining hydrogen and crankcase fumes in the intake of a diesel engine, whereby the hydrogen facilitates burning the crankcase fumes to reduce emissions and to improve mileage. The system of the &#39;466 application includes a filter in the hose carrying the crankcase fumes to the engine intake. The filter both filters the fumes and traps liquids in the fumes. In some cases, the trapped liquids have filled the filter and prevented optimal operation of the system. Further, many diesel engines draw air from the intake manifold which is pumped into a tank and used to actuate, for example, air brakes. Drawing hydrogen into such a system may result in undesirable conditions. 
     U.S. patent application Ser. No. 11/781,826 for “HYDROGEN AUGMENTED DIESEL CRANKCASE VENTILATION,” a parent of the present application, discloses a system with a filter with a drain hose for returning the trapped liquids to the crankcase. The filter drain hose has provided a good solution to the accumulation of liquid in the filter, but some systems have shown a somewhat irregular flow of fumes from the crankcase. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing an improved T fitting which results in a more uniform flow of fumes from an engine crankcase. The T fitting combines flows from an air filter and a hose connected to the engine crankcase, into coaxial paths, and then combines the flows into a combined flow. The combined flow is drawn into an intake manifold by manifold vacuum. The combining of the flows through the coaxial paths results in a more uniform flow of fumes from the crankcase. 
     In accordance with one aspect of the invention, there is provided a diesel engine having Positive Crankcase Ventilation (PCV) system. The diesel engine includes an engine block, a crankcase inside the engine block, at least one head attached to the engine block, an air intake carrying air to the at least one head, and an air filter filtering the air entering the air intake. The PCV system includes a T fitting, a fumes hose, a fresh air hose, and a combined flow hose. The T fitting includes a housing, a first inlet to the housing, a second inlet to the housing, an outlet from the housing, a first path inside the housing and connected to the first inlet to receive a first flow from the first inlet, and a second path inside the housing parallel to the first path and connected to the second inlet to receive a second flow from the second inlet, the second path ending at a combining area where the first flow and the second flow combine to form a combined flow. The fumes hose is connected between the crankcase of the diesel engine and a first one of the first inlet and the second inlet. The fresh air hose is connected between a second air filter and a second one of the first inlet and the second inlet, and the combined flow hose is connected between the outlet of the T fitting and the air intake of the diesel engine. The diesel engine may include an exhaust system with a particulate filter to reduce emissions. 
     In accordance with another aspect of the invention, there is provided a diesel engine having Positive Crankcase Ventilation (PCV) system. The diesel engine includes an engine block, a crankcase inside the engine block, at least one head attached to the engine block, an air intake carrying air to the at least one head, a turbo supercharger in cooperation with the air intake for pressurizing air entering the at least one head, and an air filter filtering the air entering the air intake. The PCV system includes a T fitting, a fumes hose, a fresh air hose, and a combined flow hose. The T fitting includes a housing, a first inlet to the housing, a second inlet to the housing, an outlet from the housing, a first path inside the housing connected to the first inlet to receive a first flow from the first inlet, a second path inside the housing parallel to the first path and connected to the second inlet to receive a second flow from the second inlet, the second path ending at a combining area where the first flow and the second flow combine to form a combined flow. The fumes hose is connected between the crankcase of the diesel engine and a first one of the first inlet and the second inlet and the fresh air hose is connected between a second air filter and a second one of the first inlet and the second inlet. The combined flow hose is connected between the outlet of the T fitting and the air intake of the diesel engine, and a fumes filter resides serially in the combined air hose to filter the combined flow and to trap liquids in the combined flow. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
         FIG. 1  is a prior art diesel engine. 
         FIG. 2A  is a side view of a T fitting according to the present invention. 
         FIG. 2B  is a top view of the T fitting according to the present invention. 
         FIG. 3  is a cross-sectional view of the T fitting taken along line  3 - 3  of  FIG. 2B . 
         FIG. 4  is an engine including a Positive Crankcase Ventilation (PCV) system including the T fitting according to the present invention with crankcase fumes drawn from a breath tube opening in an engine block. 
         FIG. 5  is a second embodiment of an engine including a combination of the PCV system and T fitting according to the present invention and a hydrogen source to promote burning of crankcase fumes, the combination according to the present invention. 
         FIG. 6  a third embodiment of an engine including a combination of the PCV system and T fitting according to the present invention and the hydrogen source to promote burning of crankcase fumes, the combination according to the present invention, with hydrogen introduced to an air intake after a turbo supercharger. 
         FIG. 7  a fourth embodiment of an engine including a combination of the PCV system and T fitting according to the present invention and the hydrogen source to promote burning of crankcase fumes, the combination according to the present invention with crankcase fumes drawn through a valve cover 
         FIG. 8  is a fifth embodiment of an engine including a combination of the PCV system and T fitting according to the present invention and the hydrogen source to promote burning of crankcase fumes, the combination according to the present invention with crankcase fumes drawn from an oil fill tube opening in the engine block. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     A typical known diesel cycle engine  10  is shown in  FIG. 1 . Diesel cycle engines generally use common diesel fuel, but may use other fuels, for example, bio diesel fuel, or the like. The diesel engine  10  includes an engine block  16  which encloses a crankcase (not shown). At least one cylinder head  17  is attached to the block  16  and includes intake and exhaust ports for carrying air and fuel into the engine and exhaust out of the engine and valves to open and close the ports. Each head  17  is covered by a valve cover  17   a . An air flow  15  used in the combustion process enters the diesel cycle engine  10  through an air filter  12 , passing through an air intake  11  into the engine  10  through the at least one head  17 . A supercharger  14  may reside in series in the air intake  11  to pressurize the air flow  15  entering the engine through the at least one head  17 . 
     The diesel cycle engine  10  further includes an oil fill cap  18  on an oil fill tube  20  for adding motor oil to the diesel cycle engine  10 . The diesel cycle engine  10  also generally includes a crankcase breather  22  with an open end  24  for venting the crankcase and allowing crankcase fumes  34 , including diesel blow-by and the like (e.g., fumes generated by the breakdown of engine oil), to escape the crankcase through an open end  24  of the breather tube  22 . 
     A side view of a T fitting  90  according to the present invention is shown in  FIG. 2A , a top view of the T fitting  90  is shown in  FIG. 2B , and a cross-sectional view of the T fitting  90  taken along line  3 - 3  of  FIG. 2B  is shown in  FIG. 3 . The T fitting  90  has a housing  92  with a first inlet  93  and a second inlet  94  extending from the housing  92 . A first flow enters the housing  92  through the inlet  93 . An inner tube  95  resides inside the housing  92  and receives a second flow from the inlet  94 . The path of the second flow is approximately parallel with the path of the first flow through the housing  92 . The inner tube  95  ends and the flows combine in a combining area  97  to create a combined flow  34   b . In one embodiment, the first flow is a fresh air flow  42  (see  FIG. 4 ) and the second flow is the crankcase fumes flow  34 . In another embodiment, the first flow is the crankcase fumes flow  34  and the second flow is the fresh air flow  42 . A clean air hose  48  is shown connected to the inlet  93  and a crankcase fumes hose  52   a  is shown connected to the inlet  94 . 
     A combined flow hose  52   b  is shown connected to the housing  92 . The combined flow hose  52   b  connects to the air intake  11  (see  FIG. 4 ) and vacuum in the air intake  11  draws a flow through the combined flow hose  52   b . The structure of the housing  92  and inner tube  95  is provided to create the generally parallel flows  34  and  42  inside the T fitting  90  so that when the flows  34  and  42  merge at the combining area  97  a steady flow is created contributing to smooth engine operation. 
     One embodiment of the T fitting  90  is shown in  FIGS. 2A ,  2 B, and  3 , but the present invention may be embodied in many other structures of T fittings. For example, the inner tube may be hard or may be a flexible hose, and may end in the housing  92 , or extend from the housing  92  into the combined flow hose  52   b . Further, the fresh air flow  42  may enter the second inlet  94  and the crankcase fumes flow  34  may enter the first inlet  93  (see  FIG. 7 ). A PCV system including any structure constraining the fresh air flow  42  and the crankcase fumes flow  34  to be generally parallel flows before being combined, is intended to come within the scope of the present invention. Within the context of the present invention, generally parallel means that the flows are constrained to paths which are approximately parallel within constraints of materials and manufacturing methods. 
     An engine  10   b  including a Positive Crankcase Ventilation (PCV) system including the T fitting  90  according to the present invention, is shown in  FIG. 4 . The crankcase fumes  34  are drawn from a breath tube opening  22   a  in an engine block  16  through the crankcase fumes hose  52   a . The fresh air flow  42  is drawn through a second air filter  40  and a fresh air hose  48  into the T fitting  90 . A back flow preventor  44  may reside in series in the fresh air hose  48  to prevent blow-by or other fumes, liquids, or solids from escaping the diesel cycle engine  10   b  through the air filter  40 . The back flow preventor  44  may further include a vacuum regulator to regulate the crankcase vacuum. The crankcase vacuum is preferably regulated to be between approximately one and approximately four pounds. A combined flow hose  52   b  is connected between the T fitting  90  and a fumes filter  36  and a filtered flow hose  52   c  is connected between the filter  36  and air intake  11 . The filtered flow hose  52   c  is connected to the air intake  11  before a supercharger when a supercharger is present so that vacuum is present in the filtered flow hose  52   c . The filter  36  may include a drain hose  37  to allow liquid trapped in the filter to return to an oil pan  60  attached to the block  16 . The system of  FIG. 4 , may, for example, be used on an engine without a hydrogen generator and with a particulate filter in the exhaust system. 
     Examples of suitable hydrogen generators are well known and described in US Patent Application Publication No. 2005/0258049 for “Hydrogen Generator For Use in a Vehicle Fuel System,” U.S. Pat. No. 4,573,435 for “Method and Apparatus for Generating Hydrogen Gas for Use As a Fuel Additive on a Diesel Engine,” U.S. Pat. No. 6,155,212 for “Method and Apparatus for Operation of Combustion Engines,” and U.S. Pat. No. 6,901,889 for “Fumigation System for a Diesel Engine”. The &#39;049 application and the &#39;435, &#39;212, and &#39;889 patents are herein incorporated by reference. An example of a suitable hydrogen generator is a Hydrogen Fuel Injection™ (HFI) system built by Canadian Hydrogen Energy Company Ltd, in Ontario, Canada. 
     A restriction  38  may be provided to restrict the flow  34   b , which restriction  38  preferably cooperates with the hose  52   c , and more preferably resides proximal to the connection point of the hose  52   c  to the air intake  11 . The restriction  38  regulates (or limits) the flow  34   b  into the air intake  11 . The restriction  38  may be manually adjustable or may be self adjusting, for example, a vacuum regulator, or may, for example, be a fixed size replaceable orifice, a variable orifice, or a clamp to squeeze the outside of the hose  52   c  to restrict the flow  34   b . The restriction  38  may be used to adjust crankcase vacuum and preferably results in between approximately one pound and approximately four pounds of crankcase vacuum, and more preferably results in approximately two pounds of crankcase vacuum. In general, a larger engine will operate with a higher crankcase vacuum, and a small engine will operate with a lower crankcase vacuum. The restriction  38  may also cooperate with a vacuum regulator  44  in the clean air hose  48  to regulate crankcase vacuum. 
     A second embodiment of an engine  10   c  including a combination of the PCV system with the T fitting  90  and a hydrogen source  26 , to promote burning of crankcase fumes  34 , is shown in  FIG. 5 . The hydrogen source  26  is connected to the air intake between the air filter  12  and turbo supercharger  14  by a hydrogen hose  28  to introduce a hydrogen flow  30  into the air flow  15 . The engine  10   c  is otherwise like the engine  10   b  shown in  FIG. 4 . Oxygen from the hydrogen source  26  may also be provided to the air intake  11  through an oxygen hose. 
     A third embodiment of an engine  10   d  including the combination of the PCV system and T fitting  90  and the hydrogen source  26  to promote burning of crankcase fumes  34 , is shown in  FIG. 6 . In the instance of the engine  10   d , the hydrogen flow  30  is introduced to the air flow  15  after a turbo supercharger  14 . The engine  10   d  is otherwise like the engine  10   b  shown in  FIG. 4 . 
     A fourth embodiment of an engine  10   e  including the PCV system and T fitting  90  is shown in  FIG. 7  with crankcase fumes  34  drawn through the valve cover  17   a . In the instance of the engine  103 , the crankcase fumes  34  enter the first inlet  93  of the T fitting  90  and the fresh air flow  42  enters the T fitting through the second inlet  94  and it is understood that the first and second inlets of the T fitting may be used for either the crankcase fumes flow or for the fresh air flow interchangeably in any embodiment of the present invention and the particular use is a matter of convenience in connecting hoses. Further, the crankcase fumes flow  34  may be drawn from the engine block, valve covers, valley cover, or any location on the engine providing access to the crankcase. The engine  10   e  is otherwise like the engine  10   b  shown in  FIG. 4 . The engine  10   b  may further include the hydrogen source  26  (see  FIG. 5 ) to promote burning of crankcase fumes  34 , and oxygen from the hydrogen source  26  may further be provided to the air intake  11  through an oxygen hose. 
     A fifth embodiment of an engine  10   f  including a combination of the PCV system and T fitting  90  and the hydrogen source to promote burning of crankcase fumes is shown in  FIG. 8  with crankcase fumes  34  drawn from an oil fill tube opening  20   a  in the engine block  16 . The engine  10   f  is otherwise like the engine  10   b  shown in  FIG. 4 . 
     Regarding the hoses referenced above, metal or plastic tubing may be used as well, or any suitable conduit, may be used to carry the flows. 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.