Patents by Inventor David Yu-Zhang Chang

David Yu-Zhang Chang 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: 11566545
    Abstract: A gas engine is disclosed. The gas engine may include a combustion cylinder. The combustion cylinder may include an intake with an intake valve. The combustion cylinder may include an exhaust with an exhaust valve. The gas engine may include a gas admission valve assembly coupled to the intake. The gas admission assembly may include a trimmable electro-hydraulically actuatable gas admission valve to control a gas flow into the intake.
    Type: Grant
    Filed: May 2, 2019
    Date of Patent: January 31, 2023
    Assignee: Caterpillar Inc.
    Inventors: David Yu Zhang Chang, David Todd Montgomery, Scott Fiveland, Scott F. Shafer
  • Patent number: 11236705
    Abstract: A gaseous fuel mixer assembly for an engine includes a mixer housing forming gas delivery openings, and positioned to extend across a flow path formed by an intake conduit for the engine. A spool valve is within a central bore in the mixer housing and includes gas distribution openings selectively connectable to the gas delivery openings by moving the spool valve within the mixer housing using a piezoelectric actuator coupled with the spool valve by way of a pivot arm. Sealing lands of the spool valve are in an alternating arrangement with the gas distribution openings, such that at the closed position the sealing lands block the gas distribution openings from the gas delivery openings, and at the open position the respective openings are fluidly connected.
    Type: Grant
    Filed: June 25, 2020
    Date of Patent: February 1, 2022
    Assignee: Caterpillar Inc.
    Inventor: David Yu Zhang Chang
  • Publication number: 20210404422
    Abstract: A gaseous fuel mixer assembly for an engine includes a mixer housing forming gas delivery openings, and positioned to extend across a flow path formed by an intake conduit for the engine. A spool valve is within a central bore in the mixer housing and includes gas distribution openings selectively connectable to the gas delivery openings by moving the spool valve within the mixer housing using a piezoelectric actuator coupled with the spool valve by way of a pivot arm. Sealing lands of the spool valve are in an alternating arrangement with the gas distribution openings, such that at the closed position the sealing lands block the gas distribution openings from the gas delivery openings, and at the open position the respective openings are fluidly connected.
    Type: Application
    Filed: June 25, 2020
    Publication date: December 30, 2021
    Applicant: Caterpillar Inc.
    Inventor: David Yu Zhang Chang
  • Patent number: 11078827
    Abstract: An ignition system for a gaseous fuel engine includes an igniter and an actuator structured to apply an actuating force to a piston within the igniter, to autoignite an ignition charge of fuel and air within the igniter. A housing of the igniter includes a gas orifice having a flow area that is increased between a combustion pre-chamber in the igniter and a main combustion chamber in the engine, to limit velocity of outgoing combustion gases to below a threshold velocity for engine mis-fire.
    Type: Grant
    Filed: October 11, 2018
    Date of Patent: August 3, 2021
    Assignee: Caterpillar Inc.
    Inventor: David Yu Zhang Chang
  • Patent number: 11078826
    Abstract: Operating an internal combustion engine system includes advancing a prechamber piston in a fuel delivery igniter to push a main charge of fuel from a prechamber into a cylinder, and advancing the prechamber piston to compression-ignite a pilot charge within the prechamber. Combustion gases of the pilot charge are conveyed into the cylinder to ignite the main charge. Operation of the engine system provides sparkless gaseous fuel ignition.
    Type: Grant
    Filed: October 28, 2020
    Date of Patent: August 3, 2021
    Assignee: Caterpillar Inc.
    Inventor: David Yu-Zhang Chang
  • Publication number: 20200347754
    Abstract: A gas engine is disclosed. The gas engine may include a combustion cylinder. The combustion cylinder may include an intake with an intake valve. The combustion cylinder may include an exhaust with an exhaust valve. The gas engine may include a gas admission valve assembly coupled to the intake. The gas admission assembly may include a trimmable electro-hydraulically actuatable gas admission valve to control a gas flow into the intake.
    Type: Application
    Filed: May 2, 2019
    Publication date: November 5, 2020
    Applicant: Caterpillar Inc.
    Inventors: David Yu Zhang CHANG, David Todd MONTGOMERY, Scott FIVELAND, Scott F. SHAFER
  • Publication number: 20200116074
    Abstract: An ignition system for a gaseous fuel engine includes an igniter and an actuator structured to apply an actuating force to a piston within the igniter, to autoignite an ignition charge of fuel and air within the igniter. A housing of the igniter includes a gas orifice having a flow area that is increased between a combustion pre-chamber in the igniter and a main combustion chamber in the engine, to limit velocity of outgoing combustion gases to below a threshold velocity for engine mis-fire.
    Type: Application
    Filed: October 11, 2018
    Publication date: April 16, 2020
    Applicant: Caterpillar Inc.
    Inventor: David Yu Zhang Chang
  • Patent number: 10072561
    Abstract: A piston for an engine is provided. The piston includes a body having a crown disposed about a central axis. The crown includes an inner circumference and an outer circumference. The piston includes a central chamber transversely disposed within the body and recessed with respect to the crown. The piston includes a central mound disposed within the central chamber about the central axis. The piston also includes a bowl extending from the central mound towards the crown. The piston further includes a passageway provided on the inner circumference of the crown. The passageway includes a slot defined by a first surface inclined at a first angle with respect to the central axis. The slot is adapted to allow flow of a fuel from the central chamber towards the outer circumference of the crown.
    Type: Grant
    Filed: July 25, 2016
    Date of Patent: September 11, 2018
    Assignee: Caterpillar Inc.
    Inventors: Weidong Gong, David Yu-Zhang Chang
  • Publication number: 20180023454
    Abstract: A piston for an engine is provided. The piston includes a body having a crown disposed about a central axis. The crown includes an inner circumference and an outer circumference. The piston includes a central chamber transversely disposed within the body and recessed with respect to the crown. The piston includes a central mound disposed within the central chamber about the central axis. The piston also includes a bowl extending from the central mound towards the crown. The piston further includes a passageway provided on the inner circumference of the crown. The passageway includes a slot defined by a first surface inclined at a first angle with respect to the central axis. The slot is adapted to allow flow of a fuel from the central chamber towards the outer circumference of the crown.
    Type: Application
    Filed: July 25, 2016
    Publication date: January 25, 2018
    Applicant: Caterpillar Inc.
    Inventors: Weidong Gong, David Yu-Zhang Chang
  • Patent number: 7318398
    Abstract: An engine valve actuation system includes an engine valve moveable between a first position that blocks a flow of fluid and a second position that allows a flow of fluid. The system also includes a valve actuation assembly connected to move the engine valve between the first position and the second position and a fluid actuator configured to selectively modify a timing of the engine valve in moving from the second position to the first position. The fluid actuator includes a first piston. The system further includes an accumulator including a second piston, wherein the second piston is slidably movable in the first piston.
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: January 15, 2008
    Assignee: Caterpillar Inc.
    Inventor: David Yu-Zhang Chang
  • Patent number: 7228826
    Abstract: The present disclosure provides an engine having a gas exchange valve and an actuator for the gas exchange valve, and also a method of reducing valve seating impact velocity. The actuator includes a body having a fluid inlet and a fluid outlet. A plunger is reciprocable in the body and has a travel distance between an advanced position and a retracted position, the plunger and body defining a chamber. A flow restriction orifice is disposed in at least one of the plunger and the body, and the chamber is in unrestricted fluid communication with the outlet over a first portion of the travel distance and in restricted fluid communication with the outlet by way of the orifice over at least a second portion of the travel distance.
    Type: Grant
    Filed: August 26, 2004
    Date of Patent: June 12, 2007
    Assignee: Caterpillar Inc
    Inventor: David Yu-Zhang Chang
  • Patent number: 6997148
    Abstract: An engine valve actuator for an internal combustion engine is provided. The actuator includes a housing having an opening. An adjustment member is disposed in the housing and defines a fluid chamber having a chamber wall. A piston is also disposed in the opening. The piston defines a piston chamber and has a pressure surface, a protrusion extending from the pressure surface, and a groove disposed in the pressure surface surrounding the protrusion and in fluid communication with the piston chamber. A fluid passageway is adapted to controllably communicate pressurized fluid to the housing opening. A push rod is operatively engageable with the piston and is adapted to controllably actuate an engine valve of the engine.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: February 14, 2006
    Assignee: Caterpillar Inc.
    Inventor: David Yu-Zhang Chang
  • Patent number: 6988471
    Abstract: An engine valve actuation system includes an engine valve moveable between first and second positions, a valve actuation assembly connected to move the engine valve between the first and second positions, a fluid actuator configured to selectively modify a timing of the engine valve in moving from the second to the first position, a source of fluid, and a pair of passages in the cylinder that allow fluid to flow from the chamber to the fluid source. The fluid actuator includes a cylinder and a piston at least partly defining a chamber. The piston is slidably movable in the cylinder between a first position and a second position, and blocks at least a portion of one of the passages at an intermediate position between the second position and the first position to reduce fluid flow from the chamber when the piston moves from the second position toward the first position.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: January 24, 2006
    Assignee: Caterpillar Inc
    Inventor: David Yu-Zhang Chang