Abstract:
The present invention is an exhaust gas recirculation (EGR) valve for an engine having an exhaust gas recirculation cooler operable for receiving exhaust gas from an exhaust, and delivering the exhaust gas to an intake. The present invention also includes an exhaust gas recirculation bypass passage operable for receiving exhaust gas from an exhaust, bypassing the exhaust gas recirculation cooler, and delivering the exhaust gas to an intake, as well as a single valve operably associated with the exhaust gas recirculation cooler and the exhaust gas recirculation bypass passage. The single valve is selectively operable for opening or closing flow from the exhaust to the exhaust gas recirculation cooler, the exhaust gas recirculation bypass passage, or both, the single valve also operable for metering flow therebetween.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/741,773, filed Dec. 2, 2005. 

   FIELD OF THE INVENTION 
   The present invention relates to EGR valves and their use in combination with an EGR cooler and an EGR cooler bypass valve. 
   BACKGROUND OF THE INVENTION 
   Future emissions requirements for Diesel Engines around the world will require engine concepts capable of achieving low NOx and low PM emissions while at the same time having a high integration of components/functions for low system cost and smallest package. Exhaust gas recirculation (EGR) valves and EGR cooler bypass valves are usually constructed as two separate valves. 
   However, often time having two valves to perform the function of delivering exhaust gas to an EGR cooler, or bypass the EGR cooler and deliver the exhaust gas directly into the intake manifold of the engine can be more costly due to the increased amount of components, or may be limited by packaging constraints. 
   Accordingly, there exists a need for a single valve to perform the function of selectively metering exhaust gas through an EGR cooler, as well as having the ability to bypass the EGR cooler partially or completely. 
   SUMMARY OF THE INVENTION 
   The present invention is an exhaust gas recirculation (EGR) valve for an engine having an exhaust gas recirculation cooler operable for receiving exhaust gas from an exhaust, and delivering the exhaust gas to an intake. The present invention also includes an exhaust gas recirculation bypass passage operable for receiving exhaust gas from an exhaust, bypassing the exhaust gas recirculation cooler, and delivering the exhaust gas to an intake, as well as a single valve operably associated with the exhaust gas recirculation cooler and the exhaust gas recirculation bypass passage. 
   The single valve is selectively operable for opening or closing flow from the exhaust to the exhaust gas recirculation cooler, the exhaust gas recirculation bypass passage, or both, the single valve also operable for metering flow therebetween. 
   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 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1  is a diagram of an engine breathing system having a high-pressure EGR loop, a low-pressure EGR loop, and a turbocharger unit; 
       FIG. 2  is a perspective, partially broken away, view of a valve in a closed position, integrated into an EGR cooler and an EGR cooler bypass conduit, according to the present invention; 
       FIG. 3  is a perspective, partially broken away, view of a valve integrated into an EGR cooler and an EGR cooler bypass conduit, and in a position to restrict exhaust gas flow through an EGR cooler bypass conduit, according to the present invention; 
       FIG. 4  is a perspective, partially broken away, view of a valve integrated into an EGR cooler and an EGR cooler bypass conduit, and in a position to restrict exhaust gas flow through the EGR cooler, according to the present invention; and 
       FIG. 5  is a perspective, partially broken away, view of a valve integrated into an EGR cooler and an EGR cooler bypass conduit, in a fully open position, according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   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. 
   An engine  10  having an exhaust gas valve according to the present invention is shown in  FIG. 1 . The engine  10  has an exhaust manifold  12  and an intake manifold  14 . There are two exhaust gas recirculation (EGR) loops, a high-pressure EGR loop  16 , and a low-pressure EGR loop  18 . The engine  10  also operates with the use of a turbocharger unit  20  which includes a turbine  22  and a compressor  24 . The high-pressure EGR loop  16  is located upstream of the turbine  22  and downstream of the compressor  24 , while the low-pressure EGR loop  18  is located downstream of the turbine  22 , and upstream of the compressor  24 . 
   Connected to the turbine  22  is a diesel particulate filter (DPF)  26  which receives exhaust gas from the turbine  22 . The low-pressure EGR loop  18  includes a combined EGR and throttle valve  28 , a first EGR conduit  30 , an EGR cooler  32 , and a second EGR conduit  34 . The second EGR conduit  34  is connected to an intake pipe  36 . The intake pipe is connected to the compressor  24 . 
   The compressor  24  is connected to a charge air cooler  38 , and a first intake conduit  40 . Located in the intake conduit  40  is charge air cooler bypass valve  42 . The high-pressure EGR loop  16  includes an exhaust gas recirculation (EGR) passage  44 , a single valve or an exhaust gas valve  46 , an exhaust gas recirculation (EGR) cooler  48 , and an exhaust gas recirculation (EGR) bypass passage  50 . In an alternate embodiment, a flow control valve  52  is incorporated into the present invention, if desired, for controlling the total amount of flow from the exhaust manifold  12 . The EGR cooler  48  and the EGR bypass passage  50  both are connected to a single pipe  54 , which is connected to a main intake conduit  56 . The main intake conduit  56  is connected to the intake manifold  14  of the engine  10 . The flow control valve  52  can be incorporated into the EGR passage  44 , the single pipe  54 , or any other location along the flow of exhaust gas to control the total amount of exhaust gas flow. 
   The exhaust gas valve  46  is shown in greater detail in  FIGS. 2-5 . In the embodiment shown in  FIG. 1 , the exhaust gas valve  46  is incorporated into the EGR cooler  48  and the EGR bypass passage  50 . However, the exhaust gas valve  46 , the EGR cooler  48 , and the bypass passage  50  can be incorporated into a single component. The EGR passage  44 , exhaust gas valve  46 , the EGR cooler  48 , and the bypass passage  50  could also all be incorporated into a single component. It is within the scope of the invention to have other variations of EGR passage  44 , exhaust gas valve  46 , the EGR cooler  48 , and the bypass passage  50  incorporated together in various ways. The exhaust gas valve  46  is comprised of a housing  60  which circumscribes a solid semi-circular disc  62 . Preferably, the exhaust gas valve  46  includes the use of a seal between the housing  60  and the semi-circular disk  62  to prevent exhaust gas leakage. The exhaust gas valve  46  can be used to control the temperature of the EGR flow, and can be used to control the gaseous temperatures entering the engine on the intake side. Also, in another alternate embodiment, the flow control valve  52  is incorporated into the housing  60  of the exhaust gas valve  46  for controlling the overall flow, as well as the flow distribution between the EGR cooler  48  and the bypass passage  50 . 
   In operation, exhaust gas from the exhaust manifold  12  flows through the EGR passage  44  and can flow into either the EGR cooler  48  or the EGR bypass passage  50 . The semi-circular disc  62  can be positioned to close both the EGR bypass passage  50  and the EGR cooler  48 , so as to not allow any exhaust gas to flow therein. When the semi-circular disc  62  is in this position, all of the exhaust gas flows from the exhaust manifold  12  directly into the turbine  22 . 
   When the semi-circular disc  62  is moved into the position shown in  FIG. 3 , the EGR bypass passage  50  is blocked, and all of the exhaust gas then flows through the EGR cooler  48 . When the semi-circular disc  62  is moved into the position shown in  FIG. 4 , the flow of exhaust gas through the EGR cooler  48  is blocked, and all of the exhaust gas recirculation flows through the EGR bypass passage  50 . 
   In  FIG. 5 , the semi-circular disc  62  is in a position such that exhaust gas is flowing through both the EGR bypass passage  50  and the EGR cooler  48 . 
   The exhaust gas valve  46  can also be used to meter the flow of exhaust gas between the EGR cooler  48  and the EGR bypass passage  50  as needed based on the various engine  10  operating conditions by actuating the semi-circular disk  62 . Distributing the flow of exhaust gas between the EGR cooler  48  and the EGR bypass passage  50  provides for control over the temperature of the exhaust gas, and control over intake manifold air temperatures. The present invention is also not limited to incorporating the exhaust gas valve  46  into the EGR bypass passage  50  and the EGR cooler  48 . The exhaust gas valve  46  can also be incorporated into a combination of the EGR passage  44  and the EGR bypass passage  50  upstream of the EGR cooler  48 . Additionally, the exhaust gas valve  46  can be integrated with some of the other components such as the turbine  22  and the EGR passage  44 , or the turbine  22  and the EGR bypass passage  50 . The pipe  54  connected to the EGR cooler  48  and the EGR bypass passage  50  could be connected to the intake pipe  36 , instead of the main intake conduit  56 , taking the exhaust gas flow from upstream of the turbine  22 , and placing the exhaust gas into system upstream of the compressor  24 . 
   Actuation of the exhaust gas valve  46  can be accomplished through the use of a single actuator (not shown), which can be pneumatic, hydraulic, or electronic, and can use any kind of linkage, gears, or other way of transferring power to rotary motion. The actuator is used for adjusting the position of the semi-circular disk  62  in response to signals received from a suitable controller. The exhaust gas valve  46  could be controlled by the vehicle&#39;s electronic control unit (not shown). When a specific temperature is desired, for instance, in the intake manifold, the electronic control unit (ECU) can actuate the exhaust gas valve  46  to direct exhaust gas through just the EGR cooler  48  or just the EGR bypass passage  50 , or meter the flow through both to adjust the temperature of the air flowing into the intake manifold  14  of the engine  10  as may be required for certain engine operating conditions. The exhaust gas valve  46 , EGR cooler  48 , and EGR bypass passage  50  can also be connected at a location upstream of the compressor  24 , allowing the exhaust gas valve  46  to control the temperature of the air flowing into the compressor  24 . 
   Also, while it has been shown that the exhaust gas valve  46  can be used in a high-pressure EGR loop  16 , the exhaust gas valve  46  of the present invention can also be used in a low-pressure EGR loop as well, or a combination high-pressure and low-pressure EGR loop. It is to be appreciated that the exhaust gas valve  46  can be used with any other type of exhaust gas recirculation system where a single valve is needed to distribute the exhaust gas flow through an EGR cooler and EGR cooler bypass passage. 
   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.