| Automotive diesel exhaust hc dosing valve -> Monitor Keywords |
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  Automotive diesel exhaust hc dosing valveRelated Patent Categories: Power Plants, Internal Combustion Engine With Treatment Or Handling Of Exhaust Gas, By Means Producing A Chemical Reaction Of A Component Of The Exhaust Gas, Condition Responsive Control Of Heater, Cooler, Igniter, Or Fuel Supply Of ReactorThe Patent Description & Claims data below is from USPTO Patent Application 20070033927. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/708,195 entitled "AUTOMOTIVE DIESEL EXHAUST HC DOSING VALVE," filed Aug. 15, 2005, the contents of which are hereby incorporated by reference herein in their entirety. FIELD OF THE INVENTION [0002] The present invention relates generally to a system for reducing particulates and nitric oxide (NO.sub.x) emissions by diesel engines, and more particularly, to a novel hydrocarbon (HC) dosing valve system that eliminates the requirement for water cooling in a high temperature environment. BACKGROUND OF THE INVENTION [0003] Hydrocarbons and NO.sub.x emissions are a direct result of the combustion process in an internal combustion engine. To reduce such harmful emissions, catalytic converters are employed to reduce their toxicity. For gasoline engines, "three-way catalysts" are used to reduce nitrogen oxides to nitrogen and oxygen (2NO.sub.x.fwdarw.xO.sub.2+N.sub.2), oxidize carbon monoxide to carbon dioxide (2CO+O.sub.2.fwdarw.2CO.sub.2); and oxidize hydrocarbons to carbon dioxide and water: C.sub.xH.sub.y+nO.sub.2.fwdarw.xCO.sub.2+mH.sub.2O. In the case of compression ignition or "Diesel" engines, the most commonly employed catalytic converter is the diesel oxidation catalyst. This catalyst employs excess O.sub.2 in the exhaust gas stream to oxidize carbon monoxide to carbon dioxide and hydrocarbons to water and carbon dioxide. These converters virtually eliminate the typical odors associated with diesel engines, and reduce visible particulates, however they are not effective in reducing NO.sub.x due to excess oxygen in the exhaust gas stream. [0004] One way of reducing NO.sub.x emissions in a diesel engine utilizes a Selective Catalytic Reduction Catalyst (SCR) in the presence of a reducing agent such as ammonia (NH.sub.3) to modify the engine exhaust. Existing technologies utilize SCR and NO.sub.x traps or NO.sub.x adsorbers. The ammonia is typically stored on board a vehicle either in pure form, either as a liquid or gas, or in a bound form that is split hydrolytically to release the ammonia into the system. [0005] An aqueous solution of urea is commonly used as a reducing agent. The urea is stored in a reducing tank that associated with the system. A dosing valve disposed on the exhaust manifold upstream of a catalytic converter meters the delivery of a selected quantity of urea into the exhaust stream. When the urea is introduced into the high temperature exhaust, it is converted to a gaseous phase and the ammonia is released to facilitate reduction of NO.sub.x. In lieu of ammonia, diesel fuel from the vehicle's fuel supply can be used as the reducing agent. In this expedient, a quantity of diesel fuel is administered directly into the exhaust via the dosing valve. [0006] In either case, the dosing valve is mounted directly on the exhaust manifold, and thus operates in a very high temperature environment that can reach temperatures as high as 600 deg C. Accordingly, the dosing valve must be cooled to prevent decomposition or crystallization of the urea prior to delivery into the exhaust stream and to maintain integrity of the valve assembly. The problems associated with this high temperature environment have previously been addressed by water cooling the assembly. However, this requires specialized plumbing and systems that ultimately increase costs and reduce reliability. SUMMARY OF THE INVENTION [0007] In view of the foregoing, it is an object of the invention to provide a dosing valve assembly for an internal combustion engine that eliminates the need for water cooling of the dosing valve. [0008] It is a further object of the invention to provide a dosing valve assembly that provides a control valve that is separated from a delivery valve mounted on the exhaust manifold to remove the control valve from the high temperature environment associated with the exhaust manifold. [0009] In accordance with aspects of the invention, a dosing valve assembly is disclosed for administering a reducing agent, such as for example, diesel fuel, into an exhaust stream within an exhaust manifold of an internal combustion engine. The dosing valve assembly comprises a control valve coupled to a source of the reducing agent, a reducing agent delivery valve constructed and arranged for coupling to the exhaust manifold to enable a specified quantity of reducing agent to be administered into the exhaust stream, and an elongated conduit disposed between the control valve and reducing agent delivery valve for fluidly communicating reducing agent from the control valve to the reducing agent delivery valve. The disclosed arrangement enables the reducing agent delivery valve to be coupled to the exhaust manifold and the control valve to be displaced from the reducing agent delivery valve and away from the high temperature environment associated with the exhaust manifold. [0010] In one expedient, a dosing valve assembly for administering a reducing agent into an exhaust stream within an exhaust manifold of an internal combustion engine in accordance with the invention comprises: an electronic fuel injector that operates as a control valve which is coupled to a source of the reducing agent; a poppet valve constructed and arranged for coupling to the exhaust manifold to enable a specified quantity of reducing agent to be administered into the exhaust stream, the poppet valve including an inlet communicating with an elongated conduit disposed between the electronic fuel injector and poppet valve for fluidly communicating reducing agent from the electronic fuel injector to the poppet valve, whereby, the poppet valve may coupled to the exhaust manifold and displaced from the electronic fuel injector. The electronic fuel injector is coupled to an electronic control unit that signals the fuel injector to permit or inhibit the flow of reducing agent to the poppet valve in response to various sensed parameters. [0011] These and other advantages of the invention will be apparent to those of ordinary skill in the art by reference to the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a schematic of an illustrative reducing agent dosing system; [0013] FIG. 2 is a schematic of a dosing valve assembly in accordance with an aspect of the invention; [0014] FIG. 3 is a schematic of an exemplary control valve in the dosing valve assembly in accordance with another aspect of the invention; and [0015] FIG. 4 is a schematic of an exemplary reducing agent delivery valve in the form of a poppet valve in accordance with yet another aspect of the invention. DETAILED DESCRIPTION OF THE INVENTION [0016] Embodiments of the invention will be described with reference to the accompanying drawing figures wherein like numbers represent like elements throughout. Before embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of the examples set forth in the following description or illustrated in the figures. The invention is capable of other embodiments and of being practiced or carried out in a variety of applications and in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. [0017] Referring to FIG. 1, there is depicted a system schematic of an exemplary reducing agent dosing system 100. Exhaust from a diesel engine (not shown) is communicated through an exhaust manifold 102 including a P-trap, which is coupled to a catalytic converter 104. The catalytic converter 104 is of the SCR type that is well known in the art, which utilizes a selective catalytic reduction method to reduce the NO.sub.x content in the exhaust stream. A reducing agent, such as diesel fuel in the exemplary embodiment, is introduced into the exhaust manifold via a dosing valve 106 that is physically attached to manifold 102. The dosing valve 106 fluidly communicates with a control valve 108 that is disposed away from manifold 102. The details of the dosing valve 106 and control valve 108 assembly are described in detail below. The control valve 106 receives a supply of diesel fuel that is stored in a fuel tank 110 via a pressure regulator 112. A fuel pump 114 supplies diesel fuel under pressure from tank 110 to regulator 112. The fuel pump 114 and the control valve 108 are electrically coupled to an electronic control unit (ECU) 116. A dosing control unit (DCU) 118 is disposed between ECU 116 and control valve 108. These components are operative to meter a quantity of diesel fuel that is injected into the exhaust stream to reduce the NO.sub.x content in the exhaust stream. The reduction is effectuated by introducing a desired quantity of diesel fuel upstream of catalytic converter 104. Pressure sensors are disposed upstream and downstream of catalytic converter 104 to enable these parameters to be communicated to ECU 116 as schematically depicted in FIG. 1. In addition, temperature sensors and NO.sub.x sensors electrically communicate with ECU 116 as is known in the art. The ECU 116 monitors various parameters including temperature, pressure and NO.sub.x content in the exhaust stream and consequently meters the introduction of diesel fuel into the exhaust stream to optimize the reduction of undesirable particulates and NO.sub.x emissions. [0018] FIG. 2 is a schematic of a dosing valve assembly 200, which generally comprises a control valve assembly 202 and poppet valve assembly 204. The control valve assembly 202 includes a fuel injector 206 that, for this application, has been modified to omit an orifice disk that atomizes a fuel charge that is delivered to an internal combustion engine in the usual manner. The fuel injector 206 is described in greater detail below. In general terms, the fuel injector 206 comprises an electronic connector 208 that couples fuel injector 206 to the ECU 116 and DCU 118 as described above and depicted in FIG. 1. The fuel injector 206 is disposed on a bracket 210 for mounting the assembly within the vehicle. A fuel inlet 212 on a first end of the fuel injector 206 receives a supply of diesel fuel from fuel tank 110 (FIG. 1). The fuel injector 206 is fluidly coupled to poppet valve assembly 204 through a connecting tube 214, which has a length sufficient to displace the control valve assembly 202 from the high temperature environment in proximity to the exhaust manifold. The poppet valve assembly 204 is mounted directly on the exhaust manifold and described in further detail below. Continue reading... Full patent description for Automotive diesel exhaust hc dosing valve Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Automotive diesel exhaust hc dosing valve patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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