Patents by Inventor Kazuya Yokota

Kazuya Yokota 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: 7461621
    Abstract: There is provided a method of starting a spark ignition engine having multiple cylinders. The method comprises supplying air and fuel for restart into a first cylinder before the engine completely stops, and igniting the mixture of the air and the fuel in the first cylinder in response to an engine start request. In accordance with the method, by supplying air and fuel into the first cylinder before the engine completely stops, the mixture of air and fuel in the first cylinder may be homogeneous at the time of the engine start request. Also, there may be less mixture turbulence and combustion may propagate better within the cylinder. These conditions may reduce the rate of combustion in the first cylinder after a start request is initiated. The slower combustion rate may decrease temperature of the combusted gas while the cylinder wall temperature is relatively low because the engine has stopped.
    Type: Grant
    Filed: September 19, 2006
    Date of Patent: December 9, 2008
    Assignee: Mazda Motor Corporation
    Inventors: Noriyuki Ota, Masahiko Fujimoto, Yasushi Murakami, Keiji Araki, Kazuya Yokota
  • Publication number: 20080146818
    Abstract: Novel bicycloester derivatives and pharmaceutically acceptable salts thereof have high DPP-IV inhibitory activity. SOLVING MEANS The novel bicycloester derivatives are represented by the general formula (1): Pharmaceutically acceptable salts thereof are also included (Example: (2S,4S)-1-[[N-(4-ethoxycarbonylbicyclo[2.2.2]oct-1-yl)amino]acetyl]-4-fluoropyrrolidine-2-carbonitrile)).
    Type: Application
    Filed: February 1, 2005
    Publication date: June 19, 2008
    Inventors: Yasumichi Fukuda, Yoshikazu Asahina, Kohei Ohata, Kazuya Yokota, Koji Murakami, Toshiyuki Matsui
  • Publication number: 20070167501
    Abstract: A novel bicyclo derivative represented by the following general formula (1), or a pharmaceutically acceptable salt thereof, acts as an effective DPP-IV inhibitor: One example is (2S,4S)-1-[[N-(4-methylbicyclo[2.2.2]oct-1-yl)amino]acetyl]-4-fluoropyrrolidine-2-carbonitrile).
    Type: Application
    Filed: February 22, 2005
    Publication date: July 19, 2007
    Inventors: Yasumichi Fukuda, Yoshikazu Asahina, Kazuya Yokota, Koji Murakami, Tomohiro Ide
  • Publication number: 20070062476
    Abstract: There is provided a method of starting a spark ignition engine having multiple cylinders. The method comprises supplying air and fuel for restart into a first cylinder before the engine completely stops, and igniting the mixture of the air and the fuel in the first cylinder in response to an engine start request. In accordance with the method, by supplying air and fuel into the first cylinder before the engine completely stops, the mixture of air and fuel in the first cylinder may be homogeneous at the time of the engine start request. Also, there may be less mixture turbulence and combustion may propagate better within the cylinder. These conditions may reduce the rate of combustion in the first cylinder after a start request is initiated. The slower combustion rate may decrease temperature of the combusted gas while the cylinder wall temperature is relatively low because the engine has stopped.
    Type: Application
    Filed: September 19, 2006
    Publication date: March 22, 2007
    Applicant: Mazda Motor Corporation
    Inventors: Noriyuki Ota, Masahiko Fujimoto, Yasushi Murakami, Keiji Araki, Kazuya Yokota
  • Patent number: 6672052
    Abstract: An exhaust gas purifying apparatus comprises a control unit (29) operative to estimate an amount of NOx absorbed by a NOx trap material (17) disposed in an exhaust passage (10) and to make an air-fuel ratio richer so as thereby to cause the NOx trap material to release sulfur when the estimated amount of NOx absorption exceeds a specified amount. Further, the control unit (29) operative to estimate an amount of sulfur absorbed by the NOx trap material (17) and to make an air-fuel ratio richer and rising a temperature of exhaust gas so as thereby to cause the NOx trap material to release sulfur when the estimated amount of sulfur absorption exceeds a specified amount. The control unit restricts an air-fuel ratio from being made richer when the NOx trap material is not expected to absorb NOx due to progress of sulfur absorption resulting from conditionally the sulfur releasing.
    Type: Grant
    Filed: June 6, 2002
    Date of Patent: January 6, 2004
    Assignee: Mazda Motor Corporation
    Inventors: Junichi Taga, Kazuya Yokota, Youichi Kuji
  • Publication number: 20030010020
    Abstract: An exhaust gas purifying apparatus comprises a control unit (29) operative to estimate an amount of NOx absorbed by a NOx trap material (17) disposed in an exhaust passage (10) and to make an air-fuel ratio richer so as thereby to cause the NOx trap material to release sulfur when the estimated amount of NOx absorption exceeds a specified amount. Further, the control unit (29) operative to estimate an amount of sulfur absorbed by the NOx trap material (17) and to make an air-fuel ratio richer and rising a temperature of exhaust gas so as thereby to cause the NOx trap material to release sulfur when the estimated amount of sulfur absorption exceeds a specified amount. The control means restricts an air-fuel ratio from being made richer when the NOx trap material is not expected to absorb NOx due to progress of sulfur absorption resulting from conditionally the sulfur releasing.
    Type: Application
    Filed: June 6, 2002
    Publication date: January 16, 2003
    Applicant: MAZDA MOTOR CORPORATION
    Inventors: Junichi Taga, Kazuya Yokota, Youichi Kuji
  • Patent number: 6449946
    Abstract: In steps S25 to S42, in order to activate an inactive catalyst earlier, the air-fuel ratio in a combustion chamber is set to be &lgr;≈1 during a period T1 after engine start until catalyst light-off at around 50% HC purifying ratio immediately after the HC purifying ratio begins to rapidly rise, before the catalyst warms up, divisional injection is made at least during the period T1 required until light-off is reached, and a swirl is weakened during the period T1 compared to a latter period which follows this period T1. The divisional injection is made and the swirl is strengthened even during the latter period.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: September 17, 2002
    Assignee: Mazda Motor Corporation
    Inventors: Youichi Kuji, Masayuki Kuroki, Junichi Taga, Kazuya Yokota, Keiji Araki
  • Patent number: 6374596
    Abstract: An exhaust-gas cleaning device comprises an absorption quantity detector (22) for determining the first and second amounts of NOx and oxygen absorbed by a NOx-absorbing material and an oxygen-absorbing material during first and second reference times based on sensing signals fed from an oxygen concentration detector (11), a NOx quantity estimator (23) for obtaining first and second estimated values of the amount of NOx absorbed by the NOx-absorbing material during the first and second reference times in accordance with engine operating condition, and a deterioration detector (24) for making a judgment on deterioration of the NOx-absorbing material based on the first and second amounts of absorption of NOx and oxygen determined by the absorption quantity detector (22) and the first and second estimated values of the amount of NOx obtained by the NOx quantity estimator (23).
    Type: Grant
    Filed: January 17, 2001
    Date of Patent: April 23, 2002
    Assignee: Mazda Motor Corporation
    Inventors: Junichi Taga, Kazuya Yokota, Youichi Kuji, Masayuki Kuroki
  • Publication number: 20010018825
    Abstract: In steps S25 to S42, in order to activate an inactive catalyst earlier, the air-fuel ratio in a combustion chamber is set to be &lgr;≈1 during a period T1 after engine start until catalyst light-off at around 50% HC purifying ratio immediately after the HC purifying ratio begins to rapidly rise, before the catalyst warms up, divisional injection is made at least during the period T1 required until light-off is reached, and a swirl is weakened during the period T1 compared to a latter period which follows this period T1. The divisional injection is made and the swirl is strengthened even during the latter period.
    Type: Application
    Filed: February 9, 2001
    Publication date: September 6, 2001
    Inventors: Youichi Kuji, Masayuki Kuroki, Junichi Taga, Kazuya Yokota, Keiji Araki
  • Publication number: 20010011453
    Abstract: An exhaust-gas cleaning device comprises an absorption quantity detector (22) for determining the first and second amounts of NOx and oxygen absorbed by a NOx-absorbing material and an oxygen-absorbing material during first and second reference times based on sensing signals fed from an oxygen concentration detector (11), a NOx quantity estimator (23) for obtaining first and second estimated values of the amount of NOx absorbed by the NOx-absorbing material during the first and second reference times in accordance with engine operating condition, and a deterioration detector (24) for making a judgment on deterioration of the NOx-absorbing material based on the first and second amounts of absorption of NOx and oxygen determined by the absorption quantity detector (22) and the first and second estimated values of the amount of NOx obtained by the NOx quantity estimator (23).
    Type: Application
    Filed: January 17, 2001
    Publication date: August 9, 2001
    Inventors: Junichi Taga, Kazuya Yokota, Youichi Kuji, Masayuki Kuroki
  • Patent number: 6269634
    Abstract: An engine control device, which is adapted for an engine provided with an NOx-absorbing material arranged in an exhaust passage for absorbing NOx in an oxygen-rich atmosphere, and releasing NOx and absorbing sulfur content when the oxygen concentration drops, includes a discriminator for judging whether the amount of sulfur absorbed by the NOx-absorbing material has reached a prescribed quantity, and a reductant concentration controller which increases the temperature of the NOx-absorbing material by decreasing a quantity related to EGR ratio for desulfurizing the NOx-absorbing material based on the result of judgment made by the discriminator. When the quantity related to the EGR ratio is decreased, the temperature of exhaust gas increases. Consequently, the temperature of the NOx-absorbing material increases and the sulfur in the NOx-absorbing material is freed and released.
    Type: Grant
    Filed: February 3, 2000
    Date of Patent: August 7, 2001
    Assignee: Mazda Motor Corporation
    Inventors: Kazuya Yokota, Junichi Taga, Youichi Kuji, Masayuki Kuroki, Akihide Takami, Kenji Okamoto, Hiroshi Yamada, Makoto Kyougoku, Seiji Miyoshi