Patents by Inventor Shi-Wai S. Cheng
Shi-Wai S. Cheng has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 8713914Abstract: A method for monitoring a hydrocarbon-selective catalytic reactor device of an exhaust aftertreatment system of an internal combustion engine operating lean of stoichiometry includes injecting a reductant into an exhaust gas feedstream upstream of the hydrocarbon-selective catalytic reactor device at a predetermined mass flowrate of the reductant, and determining a space velocity associated with a predetermined forward portion of the hydrocarbon-selective catalytic reactor device. When the space velocity exceeds a predetermined threshold space velocity, a temperature differential across the predetermined forward portion of the hydrocarbon-selective catalytic reactor device is determined, and a threshold temperature as a function of the space velocity and the mass flowrate of the reductant is determined.Type: GrantFiled: September 29, 2009Date of Patent: May 6, 2014Assignee: GM Global Technology Operations LLCInventors: Steven J. Schmieg, Michael B. Viola, Shi-Wai S. Cheng, Patricia A. Mulawa, David L. Hilden, Thompson M. Sloane, Jong H. Lee
-
Patent number: 8186151Abstract: A method for initiating a regeneration mode in selective catalytic reduction device utilizing hydrocarbons as a reductant includes monitoring a temperature within the aftertreatment system, monitoring a fuel dosing rate to the selective catalytic reduction device, monitoring an initial conversion efficiency, selecting a determined equation to estimate changes in a conversion efficiency of the selective catalytic reduction device based upon the monitored temperature and the monitored fuel dosing rate, estimating changes in the conversion efficiency based upon the determined equation and the initial conversion efficiency, and initiating a regeneration mode for the selective catalytic reduction device based upon the estimated changes in conversion efficiency.Type: GrantFiled: June 9, 2009Date of Patent: May 29, 2012Assignee: GM Global Technology Operations LLCInventors: Michael B. Viola, Steven J. Schmieg, Thompson M. Sloane, David L. Hilden, Patricia A. Mulawa, Jong H. Lee, Shi-Wai S. Cheng
-
Patent number: 8043572Abstract: A rolling regeneration diesel particulate filter and filtering process that utilizes NO produced in the process to generate additional amounts of NO2 than the NO2 produced by the diesel engine. The process includes the step of flowing diesel engine combustion exhaust through a filter system including a first section and a second section. The first section is positioned upstream of the second section with respect to the direction of the flow of the diesel engine exhaust through the filter. The first section includes a foam constructed and arranged to trap carbon-based particulates in the exhaust. A first catalyst is carried by the foam to promote the conversion of NO in the exhaust from the diesel engine to NO2. The first catalyst also promotes the reaction of NO2 with at least a portion of the carbon-based particulates trapped by the foam to form CO and NO.Type: GrantFiled: February 26, 2004Date of Patent: October 25, 2011Assignee: GM Global Technology Operations LLCInventor: Shi-Wai S. Cheng
-
Patent number: 8011177Abstract: A method and system is disclosed for regenerating a particulate filter for an exhaust system. A source of hydrocarbon is injected into the exhaust flow upstream of the filter. The injected hydrocarbon within the filter is caused to oxidize and a temperature within the filter to rise, the temperature rise being initiated at a downstream end of the filter. A temperature change at the filter is sensed in response to the oxidation of the hydrocarbon. The amount of hydrocarbon being injected into the filter is adjusted to increase the temperature within the filter above a defined threshold from the downstream end to an upstream end of the filter, the defined threshold temperature being sufficient to oxidize soot. An operational parameter indicative of the filter regeneration being complete is sensed, and further injection of the hydrocarbon into the exhaust flow is prevented in response to the sensed operational parameter.Type: GrantFiled: August 3, 2007Date of Patent: September 6, 2011Assignee: GM Global Technology Operations LLCInventor: Shi-Wai S. Cheng
-
Publication number: 20110072790Abstract: A method for monitoring a hydrocarbon-selective catalytic reactor device of an exhaust aftertreatment system of an internal combustion engine operating lean of stoichiometry includes injecting a reductant into an exhaust gas feedstream upstream of the hydrocarbon-selective catalytic reactor device at a predetermined mass flowrate of the reductant, and determining a space velocity associated with a predetermined forward portion of the hydrocarbon-selective catalytic reactor device. When the space velocity exceeds a predetermined threshold space velocity, a temperature differential across the predetermined forward portion of the hydrocarbon-selective catalytic reactor device is determined, and a threshold temperature as a function of the space velocity and the mass flowrate of the reductant is determined.Type: ApplicationFiled: September 29, 2009Publication date: March 31, 2011Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventors: Steven J. Schmieg, Michael B. Viola, Shi-Wai S. Cheng, Patricia A. Mulawa, David L. Hilden, Thompson M. Sloane, Jong H. Lee
-
Publication number: 20110041482Abstract: An exhaust gas aftertreatment device includes a single intake path for an exhaust gas feedstream from an internal combustion engine and a coated substrate including a first substrate portion fluidly in parallel with a second substrate portion. A flow modification device selectively restricts flow of the exhaust gas feedstream exclusively to the first substrate portion, exclusively to the second substrate portion, and concurrently to the first substrate portion and the second substrate portion in controllably variable proportions.Type: ApplicationFiled: August 20, 2009Publication date: February 24, 2011Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventors: Shi-Wai S. Cheng, Terry A. Talsma, Patricia A. Mulawa
-
Publication number: 20100307140Abstract: A method for initiating a regeneration mode in selective catalytic reduction device utilizing hydrocarbons as a reductant includes monitoring a temperature within the aftertreatment system, monitoring a fuel dosing rate to the selective catalytic reduction device, monitoring an initial conversion efficiency, selecting a determined equation to estimate changes in a conversion efficiency of the selective catalytic reduction device based upon the monitored temperature and the monitored fuel dosing rate, estimating changes in the conversion efficiency based upon the determined equation and the initial conversion efficiency, and initiating a regeneration mode for the selective catalytic reduction device based upon the estimated changes in conversion efficiency.Type: ApplicationFiled: June 9, 2009Publication date: December 9, 2010Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventors: Michael B. Viola, Steven J. Schmieg, Thompson M. Sloane, David L. Hilden, Patricia A. Mulawa, Jong H. Lee, Shi-Wai S. Cheng
-
Patent number: 7716921Abstract: A particulate filter for an exhaust system configured to receive an exhaust flow is disclosed. The filter includes a wall-flow filtration element having a first regeneration zone and a second regeneration zone, the first zone being downstream of the second zone, and a heat source disposed at the first regeneration zone. In response to demand for regeneration, the wall-filtration element regenerates according to a staged regeneration such that the first zone initiates regeneration ahead of the second zone, and each zone regenerates in the direction of the exhaust flow.Type: GrantFiled: January 19, 2006Date of Patent: May 18, 2010Assignee: GM Global Technology Operations, Inc.Inventor: Shi-Wai S. Cheng
-
Patent number: 7524360Abstract: A particulate filter for an exhaust system configured to manage an exhaust flow is disclosed. The particulate filter includes a housing and a wall-filtration element contained therein. The wall-flow filtration element has an inlet end and an outlet end, the outlet end having a first end-plug. The wall-flow filtration element has pores defining a porosity sufficient to trap exhaust particulates and to pass ash particles, including the first end-plug having a pore size equal to or greater than 55 micrometers and equal to or less than 250 micrometers.Type: GrantFiled: December 30, 2005Date of Patent: April 28, 2009Assignee: GM Global Technology Operations, Inc.Inventor: Shi-Wai S. Cheng
-
Publication number: 20090095247Abstract: An intake valve for a combustion engine includes a valve guide having a bore and a lower end surface surrounding the bore, and a valve stem having an upper valve stem portion moving up and down within the bore of the valve guide and a valve at the lower end of the stem. A valve guide shield is carried by the valve stem below the upper valve stem portion that moves up and down within the bore to shield the upper valve stem portion from high boiling fraction material from the fuel to lessen the accumulation of high boiling fraction between the valve stem and the valve guide.Type: ApplicationFiled: October 12, 2007Publication date: April 16, 2009Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventor: Shi-Wai S. Cheng
-
Patent number: 7334401Abstract: A particulate sensor for sensing the presence of particulates in a gas flow stream is disclosed. The particulate sensor includes a housing having a flow divider to provide a first flow path and a second flow path. A heater is disposed and configured to provide uniform heating of the two flow paths. A first temperature sensor is disposed in the first flow path downstream of the heater. A second temperature sensor is disposed in the second flow path downstream of the heater. A fine filter is disposed within the second flow path and is configured to trap carbonaceous particulates.Type: GrantFiled: January 19, 2006Date of Patent: February 26, 2008Assignee: GM Global Technology Operations, Inc.Inventor: Shi-Wai S. Cheng
-
Patent number: 7152396Abstract: A lean NOx trap operating in a lean NOx exhaust stream is progressively regenerated, sector to sector, for efficient operation of the trap and conservation of reducing gas used in the regeneration. A reductant gas distributor is inserted in the exhaust upstream of the trap. Reductant gas is carried into the exhaust duct through a conduit portion and the reductant gas stream diverged and directed through a distributor into selected cells of the trap. The NOx in the selected cells is reduced to N2 while lean NOx exhaust continues to flow through the remainder of the trap. By relative movement of the reductant gas distributor and the trap, the entire trap is progressively and continually regenerated while still preforming as a NOx trap.Type: GrantFiled: December 10, 2004Date of Patent: December 26, 2006Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Patent number: 7104238Abstract: An intake valve for a combustion engine having an intake port is disclosed. The intake includes a valve guide having an end proximate the intake port, a valve shield extending from the end of the valve guide and into the intake port, and a valve stem arranged proximate the valve guide and valve shield. The valve guide and valve stem define a first clearance dimension therebetween, and the valve shield and value stem define a second clearance dimension therebetween, wherein the second clearance dimension is equal to or greater than the first clearance dimension.Type: GrantFiled: October 22, 2003Date of Patent: September 12, 2006Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Patent number: 6837201Abstract: An intake valve for a combustion engine having an oil reservoir and adapted for combusting fuel is disclosed. The intake valve includes a valve stem and a valve guide arranged proximate the valve stem. The valve guide and valve stem define a first clearance dimension and a second clearance dimension between an inner surface of the valve guide and an outer surface of the valve stem, wherein the second clearance dimension is greater than the first clearance dimension. The second clearance dimension is sized to accept a volume of oil quantified to dissolve high boiling fraction from the fuel to lessen the accumulation of high boiling fraction between the valve stem and the valve guide.Type: GrantFiled: October 22, 2003Date of Patent: January 4, 2005Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Patent number: 6835224Abstract: An open end diesel particulate trap for removing particulates from the exhaust gas stream of the diesel engine includes a housing having an inlet opening, an outlet opening and a gas outlet and an exhaust gas path extending from the inlet opening to the gas outlet. A first portion of the exhaust gas path leads from the inlet and extends at an angle to a second portion of the exhaust gas path leading to the gas outlet. A filter element is disposed in the housing and includes a central aperture defining the first path portion. The filter element has a wall of filter material surrounding the central aperture through which the second path portion extends. A particulate reservoir is in communication with the outlet opening. When exhaust gas flows from the inlet opening to the gas outlet, particulates in the exhaust gas flowing along the first path portion can fall into the reservoir and particulates in the exhaust gas flowing along the second path portion can be trapped in the filter element wall.Type: GrantFiled: January 3, 2003Date of Patent: December 28, 2004Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Publication number: 20040166041Abstract: A rolling regeneration diesel particulate filter and filtering process that utilizes NO produced in the process to generate additional amounts of NO2 than the NO2 produced by the diesel engine. The process includes the step of flowing diesel engine combustion exhaust through a filter system including a first section and a second section. The first section is positioned upstream of the second section with respect to the direction of the flow of the diesel engine exhaust through the filter. The first section includes a foam constructed and arranged to trap carbon-based particulates in the exhaust. A first catalyst is carried by the foam to promote the conversion of NO in the exhaust from the diesel engine to NO2. The first catalyst also promotes the reaction of NO2 with at least a portion of the carbon-based particulates trapped by the foam to form CO and NO.Type: ApplicationFiled: February 26, 2004Publication date: August 26, 2004Applicant: GENERAL MOTORS CORPORATIONInventor: Shi-Wai S. Cheng
-
Patent number: 6770252Abstract: A rolling regeneration diesel particulate filter and filtering process that utilizes NO produced in the process to generate additional amounts of NO2 than the NO2 produced by the diesel engine. The process includes the step of flowing diesel engine combustion exhaust through a filter system including a first section and a second section. The first section is positioned upstream of the second section with respect to the direction of the flow of the diesel engine exhaust through the filter. The first section includes a foam constructed and arranged to trap carbon-based particulates in the exhaust. A first catalyst is carried by the foam to promote the conversion of NO in the exhaust from the diesel engine to NO2. The first catalyst also promotes the reaction of NO2 with at least a portion of the carbon-based particulates trapped by the foam to form CO and NO.Type: GrantFiled: November 21, 2001Date of Patent: August 3, 2004Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Patent number: 6764532Abstract: A particulate filter for an exhaust system having an exhaust flow and a nominal flow area includes a housing and a plurality of plates arranged parallel to each other within the housing. Each plate has a plurality of orifices and a plurality of micropockets configured to trap exhaust particulates.Type: GrantFiled: March 3, 2003Date of Patent: July 20, 2004Assignee: General Motors CorporationInventor: Shi-Wai S. Cheng
-
Publication number: 20040128964Abstract: An open end diesel particulate trap for removing particulates from the exhaust gas stream of the diesel engine includes a housing having an inlet opening, an outlet opening and a gas outlet and an exhaust gas path extending from the inlet opening to the gas outlet. A first portion of the exhaust gas path leads from the inlet and extends at an angle to a second portion of the exhaust gas path leading to the gas outlet. A filter element is disposed in the housing and includes a central aperture defining the first path portion. The filter element has a wall of filter material surrounding the central aperture through which the second path portion extends. A particulate reservoir is in communication with the outlet opening. When exhaust gas flows from the inlet opening to the gas outlet, particulates in the exhaust gas flowing along the first path portion can fall into the reservoir and particulates in the exhaust gas flowing along the second path portion can be trapped in the filter element wall.Type: ApplicationFiled: January 3, 2003Publication date: July 8, 2004Inventor: Shi-Wai S. Cheng
-
Publication number: 20030095904Abstract: A rolling regeneration diesel particulate filter and filtering process that utilizes NO produced in the process to generate additional amounts of NO2 than the NO2 produced by the diesel engine. The process includes the step of flowing diesel engine combustion exhaust through a filter system including a first section and a second section. The first section is positioned upstream of the second section with respect to the direction of the flow of the diesel engine exhaust through the filter. The first section includes a foam constructed and arranged to trap carbon-based particulates in the exhaust. A first catalyst is carried by the foam to promote the conversion of NO in the exhaust from the diesel engine to NO2. The first catalyst also promotes the reaction of NO2 with at least a portion of the carbon-based particulates trapped by the foam to form CO and NO.Type: ApplicationFiled: November 21, 2001Publication date: May 22, 2003Inventor: Shi-Wai S. Cheng