Patents by Inventor Ryuichi Yamashita

Ryuichi Yamashita 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: 6678224
    Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.
    Type: Grant
    Filed: November 25, 2002
    Date of Patent: January 13, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryuichi Yamashita, Hiroyuki Haga, Shinobu Murai
  • Publication number: 20030072227
    Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.
    Type: Application
    Filed: November 25, 2002
    Publication date: April 17, 2003
    Inventors: Ryuichi Yamashita, Hiroyuki Haga, Shinobu Murai
  • Patent number: 6504799
    Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.
    Type: Grant
    Filed: March 10, 2000
    Date of Patent: January 7, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryuichi Yamashita, Hiroyuki Haga, Shinobu Murai
  • Patent number: 4323045
    Abstract: Several embodiments of exhaust gas recirculation systems for internal combustion engines. In each embodiment an arrangement is provided for cooling at least a portion of the recirculated exhaust gases during at least some running conditions prior to reintroduction into the combustion chamber. In one embodiment, the cooled exhaust gases are mixed with uncooled exhaust gases to provide the desired temperature of exhaust gas recirculation. In another embodiment, the exhaust gases are cooled by a fan that is operated in response to the engine running condition. In addition, a device is incorporated for controlling the cooling of the exhaust gases in response to engine temperature.
    Type: Grant
    Filed: November 30, 1979
    Date of Patent: April 6, 1982
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventor: Ryuichi Yamashita
  • Patent number: 4214561
    Abstract: An induction system for an internal combustion engine that is provided with a relatively small auxiliary intake passage that delivers the intake charge to the combustion chamber at a high velocity and high degree of turbulence. Throttle valve means are provided for directing a substantial portion of the idle and low-speed intake into the chamber through this auxiliary intake passage so as to improve flame propagation and engine performance under these running conditions. The intake for the auxiliary induction passage is disposed so that it will be exposed to atmospheric pressure under at least some low-speed running characteristics so as to improve the amount of charge drawn through the auxiliary induction passage during these conditions.
    Type: Grant
    Filed: June 1, 1978
    Date of Patent: July 29, 1980
    Assignee: Yamaha Hatsukoki Kabushiki Kaisha
    Inventors: Hiromitsu Matsumoto, Ryuichi Yamashita
  • Patent number: 4195602
    Abstract: In an internal combustion engine intended to be run on a leaner-than-stoichiometric mixture, intake control means which when "enabled" permit introduction of supplementary air under deceleration conditions to prevent over-enriching which would otherwise occur when the fuel film on the induction system wall abruptly evaporates. At various temperatures, the feature is disabled completely or for short periods of time so as not to cause over-leaning of the mixture at excessively cold temperatures, or at start up at cold or merely warm conditions.
    Type: Grant
    Filed: March 6, 1978
    Date of Patent: April 1, 1980
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto
  • Patent number: 4192140
    Abstract: Apparatus and method for the protection of an exhaust gas reactor, for example a catalytic element or a thermal reactor, disposed in the exhaust conduit of an internal combustion engine which is operated on a lean air/fuel mixture. This invention provides means for protection of the exhaust gas reactor from excessive temperatures under deceleration conditions by regulating the air/fuel mixture ratio in the induction means of the engine whereby to restrict the oxidation which occurs at the reactor. One method according to the invention comprises adding supplementary air to the induction means for a limited time after the throttle is closed under deceleration conditions, and after an initial delay, adding supplementary fuel to the induction means while the engine continues to operate under deceleration conditions.
    Type: Grant
    Filed: September 3, 1974
    Date of Patent: March 11, 1980
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto
  • Patent number: 4191716
    Abstract: A carburetor for internal combustion engines including an intake passage leading to a combustion chamber of the engine, a main fuel nozzle opening to the intake passage, a main throttle valve device provided in said intake passage, a float chamber for supplying fuel to said main fuel nozzle, a starting air passage opening to the intake passage at the downstream side of the throttle valve shut-off valve in the starting air passage, a second float chamber for supplying fuel to said starting air passage, and a passage introducing intake suction pressure to the upper portion of only the second float chamber. Also disclosed is apparatus wherein the main fuel nozzle and starting fuel nozzle communicate with a common float chamber, and the starter valve means comprises means for connecting the overlaying region of said float chamber with the intake passage downstream of the throttle valve when the starter valve means is in the open position.
    Type: Grant
    Filed: December 18, 1978
    Date of Patent: March 4, 1980
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto
  • Patent number: 4144861
    Abstract: Internal combustion engine including a fuel supply system which comprises a main carburetor having an intake passage leading to a combustion chamber of the engine. The engine is further provided with a starting fuel supply device which includes a starting fuel supply passage having one end opening to atmosphere and the other end connected with the intake passage. The starting fuel supply passage is provided with a fuel discharge nozzle and a starter valve disposed downstream of the nozzle. The supply passage has a cross-sectional area which is small in relation to that of the intake passage so that adequate air flow speed can be ensured even in engine starting period.
    Type: Grant
    Filed: May 12, 1976
    Date of Patent: March 20, 1979
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto, Masato Eda
  • Patent number: 4117813
    Abstract: An internal combustion engine and means to operate the same to produce minimal quantities and concentrations of oxides of nitrogen (NOx), carbon monoxide (CO) and unburned hydrocarbons (HC). The engine is operated with a lean air/fuel mixture at both low and high load conditions, thereby minimizing said emissions. Low load operation on lean mixtures is made possible by means and methods for maintaining at a suitably low numerical value the residual fraction which is defined as the ratio of gases in a cylinder from a previous cycle and the total gases in the cylinder for the next cycle (said gases from a previous cycle plus new mixture). Said means may comprise apparatus to shorten the duration of intake and exhaust valve overlap, or of opening the engine throttle wider than normal and retarding the ignition to reduce the engine speed at low loads. Means is preferably provided wherein the fuel in the air/fuel mixture is well-vaporized and the mixture is uniform and homogeneous.
    Type: Grant
    Filed: October 28, 1976
    Date of Patent: October 3, 1978
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto
  • Patent number: 4106464
    Abstract: A system and method for controlling a lean-burning internal combustion engine. The system and method enable a starter carburetor to operate at cold but not at hot temperature, to provide gulp air and counterbalance means for the starter carburetor, together with means to inhibit them at startup and for a brief time thereafter, and to inhibit exhaust gas recirculation when it would be deleterious to smooth operation. The system also provides for continuous accelerator pump operation during acceleration except at high temperatures. The objective is to secure smooth operation at startup, cold, warm or hot, and during transient conditions during engine warmup.
    Type: Grant
    Filed: August 24, 1976
    Date of Patent: August 15, 1978
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Ryuichi Yamashita, Hiromitsu Matsumoto, Masato Eda