Patents by Inventor Takashi Yohso
Takashi Yohso 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).
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Patent number: 7784443Abstract: A spark-ignition gasoline engine having at least a spark plug, the engine including an engine body having a geometrical compression ratio set at 14 or more, and an intake valve and an exhaust valve provided, respectively, in intake and exhaust ports connected to each of a plurality of cylinders of the engine body. The intake and exhaust valves are adapted to open and close corresponding respective ones of the intake and exhaust ports. The engine further includes an operation-state detector adapted to detect an operation state of the engine body and a control system adapted, based on detection of the operation-state detector, to perform at least an adjustment control of an ignition timing of the spark plug, the control system being operable, when an engine operation zone is a high-load operation zone including a wide open throttle region within at least a low speed range, to retard the ignition timing to a point within a predetermined stroke range just after a top dead center of a compression stroke.Type: GrantFiled: January 30, 2009Date of Patent: August 31, 2010Assignee: Mazda Motor CorporationInventors: Mitsuo Hitomi, Noriyuki Iwata, Masahisa Yamakawa, Toshiaki Nishimoto, Takashi Yohso, Takayoshi Hayashi
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Publication number: 20090159045Abstract: A spark-ignition gasoline engine having at least a spark plug, the engine including an engine body having a geometrical compression ratio set at 14 or more, and an intake valve and an exhaust valve provided, respectively, in intake and exhaust ports connected to each of a plurality of cylinders of the engine body. The intake and exhaust valves are adapted to open and close corresponding respective ones of the intake and exhaust ports. The engine further includes an operation-state detector adapted to detect an operation state of the engine body and a control system adapted, based on detection of the operation-state detector, to perform at least an adjustment control of an ignition timing of the spark plug, the control system being operable, when an engine operation zone is a high-load operation zone including a wide open throttle region within at least a low speed range, to retard the ignition timing to a point within a predetermined stroke range just after a top dead center of a compression stroke.Type: ApplicationFiled: January 30, 2009Publication date: June 25, 2009Applicant: MAZDA MOTOR CORPORATIONInventors: Mitsuo Hitomi, Noriyuki Iwata, Masahisa Yamakawa, Toshiaki Nishimoto, Takashi Yohso, Takayoshi Hayashi
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Patent number: 7484498Abstract: Disclosed is a spark-ignition gasoline engine, which comprises control means operable, when an engine operation zone is a high-load operation zone including a WOT region within at least a low speed range, to adjust a closing timing of an intake valve in such a manner as to maintain an effective compression ratio at 13 or more, and retard an ignition timing to a point within a predetermined stroke range just after a top dead center of a compression stroke, wherein the effective compression ratio is calculated based on an intake-valve closing timing defined by a valve lift amount of 1 mm. The present invention can provide a spark-ignition gasoline engine having both a low-cost performance and a high engine-power performance even in a high-load operation zone (particularly WOT region) in a low speed range.Type: GrantFiled: March 28, 2007Date of Patent: February 3, 2009Assignee: Mazda Motor CorporationInventors: Mitsuo Hitomi, Noriyuki Iwata, Masahisa Yamakawa, Toshiaki Nishimoto, Takashi Yohso, Takayoshi Hayashi
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Patent number: 7360531Abstract: This invention relates to a combustion chamber structure for a spark-ignition engine, which comprises a combustion chamber defined between a bottom surface of a cylinder head and a top surface of a piston in such a manner that the bottom surface of the cylinder head serves as a ceiling wall thereof, and a spark plug having a sparking end protruding from the ceiling wall into the combustion chamber. In this combustion chamber structure, when the piston is at a top dead center, a principal space of the combustion chamber is comprised of a first combustion space around the sparking end of the spark plug and a second combustion space around a circumference of a cylinder bore. Further, the first combustion space and the second combustion space are communicated with each other through a small interspace zone where an interspace between the ceiling wall and the top surface of the piston is narrowed. The combustion chamber structure makes it possible to increase compression ratio in a practically effective manner.Type: GrantFiled: September 14, 2006Date of Patent: April 22, 2008Assignee: OKI Electric Industry Co., Ltd.Inventors: Takashi Yohso, Masahisa Yamakawa, Kouji Shishime, Toshiaki Nishimoto
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Publication number: 20070227503Abstract: Disclosed is a spark-ignition gasoline engine, which comprises control means operable, when an engine operation zone is a high-load operation zone including a WOT region within at least a low speed range, to adjust a closing timing of an intake valve in such a manner as to maintain an effective compression ratio at 13 or more, and retard an ignition timing to a point within a predetermined stroke range just after a top dead center of a compression stroke, wherein the effective compression ratio is calculated based on an intake-valve closing timing defined by a valve lift amount of 1 mm. The present invention can provide a spark-ignition gasoline engine having both a low-cost performance and a high engine-power performance even in a high-load operation zone (particularly WOT region) in a low speed range.Type: ApplicationFiled: March 28, 2007Publication date: October 4, 2007Inventors: Mitsuo Hitomi, Noriyuki Iwata, Masahisa Yamakawa, Toshiaki Nishimoto, Takashi Yohso, Takayoshi Hayashi
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Publication number: 20070056556Abstract: This invention relates to a combustion chamber structure for a spark-ignition engine, which comprises a combustion chamber defined between a bottom surface of a cylinder head and a top surface of a piston in such a manner that the bottom surface of the cylinder head serves as a ceiling wall thereof, and a spark plug having a sparking end protruding from the ceiling wall into the combustion chamber. In this combustion chamber structure, when the piston is at a top dead center, a principal space of the combustion chamber is comprised of a first combustion space around the sparking end of the spark plug and a second combustion space around a circumference of a cylinder bore. Further, the first combustion space and the second combustion space are communicated with each other through a small interspace zone where an interspace between the ceiling wall and the top surface of the piston is narrowed. The combustion chamber structure makes it possible to increase compression ratio in a practically effective manner.Type: ApplicationFiled: September 14, 2006Publication date: March 15, 2007Applicant: MAZDA MOTOR CORPORATIONInventors: Takashi Yohso, Masahisa Yamakawa, Kouji Shishime, Toshiaki Nishimoto
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Patent number: 6923156Abstract: A throttle device is arranged in the midstream of an individual passage consisting of a low-speed individual intake passage and a high-speed individual intake passage on the downstream of a surge tank. A valve body is rotatably provided in the throttle valve device. The inside of the valve body is formed with an in-valve low-speed passage and an in-valve high-speed passage that are adjacently placed with respect to the rotational axis of the valve body. The intake air supply is performed through only the low-speed individual passage when the opening of the valve body is equal to or less than a predetermined value, and through both the low-speed individual intake passage and high-speed individual intake passage when the opening of the body is larger than the predetermined value.Type: GrantFiled: September 24, 2003Date of Patent: August 2, 2005Assignee: Mazda Motor CorporationInventors: Noriyuki Iwata, Shigeyuki Hirashita, Takashi Yohso, Tatsuya Fujikawa
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Publication number: 20040144359Abstract: A throttle valve device is arranged in the midstream of an individual passage consisting of a low-speed individual intake passage and a high-speed individual intake passage on the downstream of a surge tank. A valve body is rotatably provided in the throttle valve device. The inside of the valve body is formed with an in-valve low-speed passage and an in-valve high-speed passage that are adjacently placed with respect to the rotational axis of the valve body. The intake air supply is performed through only the low-speed individual passage when the opening of the valve body is equal to or less than a predetermined value, and through both the low-speed individual intake passage and high-speed individual intake passage when the opening of the valve body is larger than the predetermined value.Type: ApplicationFiled: September 24, 2003Publication date: July 29, 2004Applicant: Mazda Motor CorporationInventors: Noriyuki Iwata, Shigeyuki Hirashita, Takashi Yohso, Tatsuya Fujikawa