David D Chang

US Patent:

6360717, Mar 26, 2002

Filed:

Aug 14, 2000

Appl. No.:

09/638634

Inventors:

David Y. Chang - Savoy IL
David C. Mack - Pontiac IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F02M 3704

US Classification:

123381, 123494

Abstract:

The present invention provides a fuel injection system and method of operating the fuel injection system. The fuel injection system includes at least one hydraulically actuated fuel injector fluidly connected with a source of high pressure actuation fluid. A viscosity sensor determines the viscosity of the hydraulically actuated fuel injector. A controller in communication with the fuel injector and the viscosity sensor is configured to determine the rate of change of the viscosity of the high pressure hydraulic actuation fluid. The supply of high pressure actuated fluid to the fuel injector is based, at least in part, on the rate of change of the determined viscosity of the high pressure actuation fluid.

US Patent:

6708656, Mar 23, 2004

Filed:

Dec 19, 2002

Appl. No.:

10/322483

Inventors:

David Y. Chang - Savoy IL

Assignee:

Caterpillar Inc - Peoria IL

International Classification:

F01L 902

US Classification:

123 9012, 92 136, 92 138

Abstract:

An engine valve actuator for an internal combustion engine is provided. The engine valve actuator includes a housing having an opening. An adjustment member is disposed in the housing and defines a chamber. A piston is disposed in the opening of the housing and has a protrusion adapted to be received in the chamber of the adjustment member. The piston has a first position where the protrusion of the piston is disposed in the chamber and a portion of the piston contacts a corresponding portion of the adjustment member and a second position where the portion of the piston is separated from the corresponding portion of the adjustment member. A fluid passageway is adapted to provide pressurized fluid to the opening. The pressurized fluid acts on the piston to move the piston towards the second position to thereby allow pressurized fluid to enter the chamber to prevent the piston from returning to the first position. A push rod is operatively engaged with the piston and is adapted to engage and open the engine valve.

US Patent:

6769385, Aug 3, 2004

Filed:

Mar 12, 2003

Appl. No.:

10/385503

Inventors:

David Y. Chang - Savoy IL

Assignee:

Caterpillar Inc - Peoria IL

International Classification:

F01L 134

US Classification:

123 9016, 123 9012, 123 9049, 123 9055, 123 9057

Abstract:

A velocity control system for an engine valve is provided. The system includes a valve having a housing defining an opening, a chamber adapted to receive a fluid, a first fluid passageway connecting the opening with the chamber, a second fluid passageway connecting the opening with the chamber, and a third fluid passageway connecting the opening with the chamber. A piston is slidably disposed in the chamber and is moveable from a first position to a second position. The movement of the piston from the first position to the second position forces fluid from the chamber at a first flow rate during movement of the piston through a first travel distance and at a second flow rate during movement of the piston through a second travel distance. The first flow rate is greater than the second flow rate. A check valve is adapted to prevent fluid from flowing from the chamber through the first fluid passageway when the piston is moving from the first position to the second position.

US Patent:

6957634, Oct 25, 2005

Filed:

Oct 4, 2002

Appl. No.:

10/263799

Inventors:

David Y. Chang - Savoy IL, US

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F01L009/02

US Classification:

123 9012, 123 9045, 123 9046, 123 9052

Abstract:

An engine valve actuator for an internal combustion engine is provided. The engine valve actuator includes a housing having an opening and a first fluid passageway leading to the opening. An adjustment member is disposed in the housing and includes a protrusion that extends into the opening of the housing. A piston is disposed in the opening of the housing and has a bore adapted to receive the protrusion, a chamber, and a second fluid passageway that connects the bore with the chamber. The piston is adapted to move in a first direction relative to the housing in response to an introduction of pressurized fluid into the first fluid passageway. The piston moves in the first direction until the protrusion substantially withdraws from the bore. A push rod is operatively engaged with the piston such that movement of the piston in the first direction causes a corresponding movement of the push rod to thereby engage and open the engine valve.

US Patent:

7178491, Feb 20, 2007

Filed:

Jun 5, 2003

Appl. No.:

10/454616

Inventors:

David Y. Chang - Savoy IL, US

Assignee:

Caterpillar Inc - Peoria IL

International Classification:

F01L 9/02

US Classification:

123 9013, 123 9015, 123 9016, 123 9012, 123320

Abstract:

A system and method for controlling a variable valve actuation system for an engine is provided. An engine valve is moved between a first position where the engine valve blocks a flow of fluid and a second position where the engine valve allows a flow of fluid. Fluid is provided to a chamber of a valve actuator adapted to operatively engage the engine valve. A parameter indicative of a viscosity of the fluid provided to the chamber of the valve actuator is sensed. Fluid is trapped within the chamber of the valve actuator to prevent the engine valve from moving to the first position. A response time of the valve actuator is determined based on the viscosity of the fluid provided to the chamber of the valve actuator. The response time indicates the time required to release the fluid from the chamber of the valve actuator to allow the engine valve to move to the first position.

US Patent:

20050274337, Dec 15, 2005

Filed:

Jun 1, 2005

Appl. No.:

11/141201

Inventors:

David Chang - Savoy IL, US

International Classification:

F01L009/02
F02D013/04

US Classification:

123090120, 123090140

Abstract:

An engine valve actuator for an internal combustion engine is provided. The engine valve actuator includes a housing having an opening and a first fluid passageway leading to the opening. An adjustment member is disposed in the housing and includes a protrusion that extends into the opening of the housing. A piston is disposed in the opening of the housing and has a bore adapted to receive the protrusion, a chamber, and a second fluid passageway that connects the bore with the chamber. The piston is adapted to move in a first direction relative to the housing in response to an introduction of pressurized fluid into the first fluid passageway. The piston moves in the first direction until the protrusion substantially withdraws from the bore. A push rod is operatively engaged with the piston such that movement of the piston in the first direction causes a corresponding movement of the push rod to thereby engage and open the engine valve.

US Patent:

46200495, Oct 28, 1986

Filed:

Oct 31, 1984

Appl. No.:

6/666896

Inventors:

Gregory E. Schmidt - Naperville IL
Linus K. Leung - Naperville IL
Lawrence J. Beck - Bolingbrook IL
David S. Chang - Cincinnati OH

Assignee:

Standard Oil Company (Indiana) - Chicago IL

International Classification:

C07C 200

US Classification:

585501

Abstract:

The method is particularly adapted for controlling the molecular weight of a product output from a polybutene reactor. The method includes the steps of: deriving from the operating parameter of a polybutene reactor system a formula which correlates molecular weight as determined by product viscosity or other parameters of the product output with operating variables such as temperature of the reactor and concentration of isobutylene in the reactor, which concentration can be controlled by the amount of catalyst, e. g. , aluminum chloride, being fed into the reactor; monitoring (a) the temperature of the reactor, (b) the concentration of isobutylene in the reactor, (c) the flow of coolant supplied to the reactor for controlling the temperature thereof and (d) the feed rate of catalyst into the reactor; calculating with said algorithm the approximate molecular weight of the product output; determining if the desired product molecular weight is higher or lower than the calculated molecular weight; and, if higher or lower, altering, through use of the formula, the temperature and/or the concentration of isobutylene in the reactor to obtain the desired product molecular weight. Also the method can include the step of adding moisture to the feed or the reactor for lowering the molecular weight of the polybutene product output. The apparatus includes a reactor, a computer and various sensing, monitoring and control devices for carrying out the steps of the method.

US Patent:

20220382833, Dec 1, 2022

Filed:

Sep 23, 2021

Appl. No.:

17/483288

Inventors:

- San Diego CA, US
Gary Jorgensen - San Diego CA, US
Bijan Golkar - San Diego CA, US
David Chang - San Diego CA, US

Assignee:

AirHop Communications, Inc. - San Diego CA

International Classification:

G06F 17/18
G06F 17/16
G06F 11/34

Abstract:

Techniques for automatic adaptive anomaly detection are disclosed. In some embodiments, a system, a process, and/or a computer program product for automatic anomaly detection includes handling invalid or missing data, building a model for the normal or typical statistical relationship between data, using the model to generate an anomaly score for each input set of data, threshold detection and persistence filtering, and automatic label generation for detected anomalies.