Patents by Inventor Shi-Wai Cheng

Shi-Wai 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).

  • Publication number: 20070266701
    Abstract: 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: Application
    Filed: August 3, 2007
    Publication date: November 22, 2007
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventor: Shi-Wai Cheng
  • Publication number: 20070163233
    Abstract: 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: Application
    Filed: January 19, 2006
    Publication date: July 19, 2007
    Inventor: Shi-Wai Cheng
  • Publication number: 20070044458
    Abstract: 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: Application
    Filed: January 19, 2006
    Publication date: March 1, 2007
    Inventor: Shi-Wai Cheng
  • Publication number: 20060156702
    Abstract: 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: Application
    Filed: December 30, 2005
    Publication date: July 20, 2006
    Inventor: Shi-Wai Cheng
  • Publication number: 20060123771
    Abstract: 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: Application
    Filed: December 10, 2004
    Publication date: June 15, 2006
    Inventor: Shi-Wai Cheng
  • Publication number: 20050087164
    Abstract: An intake valve for a combustion engine having an intake port is disclosed. The intake valve 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 valve stem define a second clearance dimension therebetween, wherein the second clearance dimension is equal to or greater than the first clearance dimension.
    Type: Application
    Filed: October 22, 2003
    Publication date: April 28, 2005
    Inventor: Shi-Wai Cheng
  • Publication number: 20050050870
    Abstract: A particulate filter for an exhaust system configured to manage an exhaust flow includes a housing and a wall-flow filtration element contained within the housing. The wall-flow filtration element is configured to trap exhaust particulates and to pass ash particles.
    Type: Application
    Filed: March 3, 2003
    Publication date: March 10, 2005
    Inventor: Shi-Wai Cheng