Patents by Inventor Tohru Yoshinaga
Tohru Yoshinaga 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: 8033273Abstract: A plasma ignition system includes an ignition plug attached to an engine and having a center electrode, a ground electrode, and a discharge space, a discharge power source circuit, a plasma generation power source circuit, a resistance element between the discharge power source circuit and the center electrode, a rectifying device between the plasma generation power source circuit and the center electrode, and an element receiving portion in a periphery of the center electrode. The plug puts gas in the discharge space into a plasma state to ignite a fuel/air mixture in the engine, as a result of application of high voltage to the plug by the discharge power source circuit and supply of high current to the plug by the plasma generation power source circuit. The resistance element and the rectifying device are placed in the receiving portion.Type: GrantFiled: June 30, 2008Date of Patent: October 11, 2011Assignee: Denso CorporationInventors: Hideyuki Kato, Tohru Yoshinaga, Masamichi Shibata
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Patent number: 7948158Abstract: A plasma ignition system includes an ignition plug attached to an engine and a high-voltage supply. The plug includes a center electrode serving as a positive pole, a ground electrode serving as a negative pole, and an insulating member insulating the center electrode from the ground electrode and defining a discharge space therein. At least a part of a surface of the center electrode faces the space, and at least a part of a surface of the ground electrode faces the discharge space. The plug puts gas in the space into a plasma state and injects the gas into the engine as a result of application of high voltage and supply of a large current to the plug by the high-voltage supply. The center electrode has a recess portion opposed to the space and recessed in a direction opposite to an injection direction.Type: GrantFiled: July 17, 2008Date of Patent: May 24, 2011Assignee: Denso CorporationInventors: Hideyuki Kato, Tohru Yoshinaga
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Patent number: 7661401Abstract: A laser type ignition device for an internal combustion engine includes a laser oscillator mounted in the internal combustion engine so as to focus its laser beam on an air-fuel mixture supplied into the combustion chamber, a pressure sensor for detecting pressure in the combustion chamber, a power source for the laser oscillator and a control unit for controlling the power source to supply the laser oscillator with the current whose amount changes according to the pressure in the combustion chamber. The power of the laser beam increases as the pressure in the combustion chamber decreases to completely ignite the air-fuel mixture.Type: GrantFiled: April 28, 2006Date of Patent: February 16, 2010Assignees: Denso Corporation, Nipoon Soken, Inc., Inter-University Research Institute Corporation National Institutes of Natural SciencesInventors: Yukinobu Anezaki, Kenji Kanehara, Aki Abe, Tohru Yoshinaga, Takunori Taira
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Publication number: 20090021133Abstract: A plasma ignition system includes an ignition plug attached to an engine and a high-voltage supply. The plug includes a center electrode serving as a positive pole, a ground electrode serving as a negative pole, and an insulating member insulating the center electrode from the ground electrode and defining a discharge space therein. At least a part of a surface of the center electrode faces the space, and at least a part of a surface of the ground electrode faces the discharge space. The plug puts gas in the space into a plasma state and injects the gas into the engine as a result of application of high voltage and supply of a large current to the plug by the high-voltage supply. The center electrode has a recess portion opposed to the space and recessed in a direction opposite to an injection direction.Type: ApplicationFiled: July 17, 2008Publication date: January 22, 2009Applicant: DENSO CORPORATIONInventors: Hideyuki Kato, Tohru Yoshinaga
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Publication number: 20090007893Abstract: A plasma ignition system includes an ignition plug attached to an engine and having a center electrode, a ground electrode, and a discharge space, a discharge power source circuit, a plasma generation power source circuit, a resistance element between the discharge power source circuit and the center electrode, a rectifying device between the plasma generation power source circuit and the center electrode, and an element receiving portion in a periphery of the center electrode. The plug puts gas in the discharge space into a plasma state to ignite a fuel/air mixture in the engine, as a result of application of high voltage to the plug by the discharge power source circuit and supply of high current to the plug by the plasma generation power source circuit. The resistance element and the rectifying device are placed in the receiving portion.Type: ApplicationFiled: June 30, 2008Publication date: January 8, 2009Applicant: DENSO CORPORATIONInventors: Hideyuki Kato, Tohru Yoshinaga, Masamichi Shibata
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Publication number: 20080121200Abstract: A plasma type ignition plug for igniting an internal combustion engine is disclosed having a negative electrode, a positive electrode, and a discharging distance fixing member, which includes an electrically conductive material replenishing section, made of an electrically conductive material available to melt when subjected to a heat of gas in plasma state, and an electrically conductive material replenished section to which the electrically conductive material is replenished. The discharging distance fixing member is covered on a surface of the negative electrode for initiating the spark discharge between a surface of the discharging distance fixing member and the positive electrode so as to avoid a fluctuation in a spark discharge distance caused by a wear of the negative electrode due to a collision of gas in the plasma state.Type: ApplicationFiled: November 20, 2007Publication date: May 29, 2008Applicant: DENSO CORPORATIONInventors: Hideyuki Kato, Tohru Yoshinaga
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Patent number: 7267116Abstract: A power-saving type of ignition apparatus is provided with a spark plug of which electrodes (30, 40) are regulated in their shapes to lower an amount of energy required for its ignition. To face to a tip (31) of a center electrode (30) extending from a mounting bracket (10), a cylindrical protrusion (41) is built on one surface (43) of an earth electrode (40). The protrusion extends toward the center electrode to form a discharge gap (50) between the protrusion and the tip of the center electrode. Both of the tip of the center electrode and the protrusion of the earth electrode are 2.3 [mm] or less in each diameter (D1, D2), thus an amount of energy required for ignition being limited to 17 [mJ] or less.Type: GrantFiled: February 13, 2002Date of Patent: September 11, 2007Assignees: DENSO Corporation, Nippon Soken, Inc.Inventors: Tetsuya Miwa, Tohru Yoshinaga, Keiji Kanao, Shinichi Okabe
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Publication number: 20060243238Abstract: A laser type ignition device for an internal combustion engine includes a laser oscillator mounted in the internal combustion engine so as to focus its laser beam on an air-fuel mixture supplied into the combustion chamber, a pressure sensor for detecting pressure in the combustion chamber, a power source for the laser oscillator and a control unit for controlling the power source to supply the laser oscillator with the current whose amount changes according to the pressure in the combustion chamber. The power of the laser beam increases as the pressure in the combustion chamber decreases to completely ignite the air-fuel mixture.Type: ApplicationFiled: April 28, 2006Publication date: November 2, 2006Applicants: DENSO CORPORATION, NIPPON SOKEN, INC., INTER-UNIVERSITY RESEARCH INSTITUTE CORPORATION NATIONAL INSTITUTES OF NATURAL SCIENCESInventors: Yukinobu Anezaki, Kenji Kanehara, Aki Abe, Tohru Yoshinaga, Takunori Taira
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Patent number: 7086363Abstract: A power-saving type of ignition apparatus is provided with a spark plug of which electrodes (30, 40) are regulated in their shapes to lower an amount of energy required for its ignition. To face to a tip (31) of a center electrode (30) extending from a mounting bracket (10), a cylindrical protrusion (41) is built on one surface (43) of an earth electrode (40). The protrusion extends toward the center electrode to form a discharge gap (50) between the protrusion and the tip of the center electrode. Both of the tip of the center electrode and the protrusion of the earth electrode are 2.3 [mm] or less in each diameter (D1, D2), thus an amount of energy required for ignition being limited to 17 [mJ] or less.Type: GrantFiled: August 26, 2004Date of Patent: August 8, 2006Assignees: Denso Corporation, Nippon Soken, Inc.Inventors: Tetsuya Miwa, Tohru Yoshinaga, Keiji Kanao, Shinichi Okabe
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Publication number: 20050016485Abstract: A power-saving type of ignition apparatus is provided with a spark plug of which electrodes (30, 40) are regulated in their shapes to lower an amount of energy required for its ignition. To face to a tip (31) of a center electrode (30) extending from a mounting bracket (10), a cylindrical protrusion (41) is built on one surface (43) of an earth electrode (40). The protrusion extends toward the center electrode to form a discharge gap (50) between the protrusion and the tip of the center electrode. Both of the tip of the center electrode and the protrusion of the earth electrode are 2.3 [mm] or less in each diameter (D1, D2), thus an amount of energy required for ignition being limited to 17 [mJ] or less.Type: ApplicationFiled: August 26, 2004Publication date: January 27, 2005Inventors: Tetsuya Miwa, Tohru Yoshinaga, Keiji Kanao, Shinichi Okabe
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Patent number: 6734677Abstract: A combustion condition detecting device detects combustion ions between opposing electrodes in a combustion chamber by ion current flowing between the electrodes in response to a.c. current voltage applied between the electrodes. A low pass filter for eliminating current components having high order frequencies of the a.c. voltage is disposed in a primary side of the transformer so that a waveform of the a.c. voltage approximates a sine wave. Thus, detection accuracy of the combustion ions is prevented from being affected by variation of capacitive current included in the current flowing between the electrodes, wherein the variation of the capacitive current is caused by distortion of the waveform of the a.c. voltage.Type: GrantFiled: October 15, 2002Date of Patent: May 11, 2004Assignee: Denso CorporationInventors: Makoto Toriyama, Tohru Yoshinaga, Hiroshi Yorita
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Patent number: 6675785Abstract: An insulator includes a coil side cylindrical portion extending from a plug side cylinder portion in a direction departing from a combustion chamber. One end of the coil side cylindrical portion protrudes in the direction departing from the combustion chamber with respect to a primary winding and a secondary winding. A pressure sensing element is disposed next to the one end of the coil side cylindrical portion. The signal lines of the pressure sensing element are taken out of a casing without passing aside an ignition coil. Thus, the diameter of the casing does not increase. The output signal of the pressure sensing element is not adversely influenced by discharge noises generated from the ignition coil.Type: GrantFiled: March 27, 2003Date of Patent: January 13, 2004Assignee: Denso CorporationInventors: Tetsuya Miwa, Atsuya Mizutani, Takeo Maekawa, Hiromi Hiramatsu, Tohru Yoshinaga
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Patent number: 6653840Abstract: In an engine ignition unit, a transistor and a current detecting resistor are connected to primary and secondary windings of an ignition coil, respectively. The current detecting resistor is used for detecting a current flowing between the opposing electrodes of spark plug. At an ignition by the spark plug, high-frequency square wave signals are generated by an oscillator after an ignition signal is cut off. The square wave signals turn on and off the transistor. By this operation, a battery voltage is intermittently applied to the primary winding and an ion current is measured. A frequency of the square wave signals is set close to a resonant frequency of an ion current path including the spark plug, the secondary winding of the ignition coil and the current detecting resistor.Type: GrantFiled: April 4, 2002Date of Patent: November 25, 2003Assignees: Nippon Soken, Inc., Denso CorporationInventors: Hiroshi Yorita, Masatoshi Ikeda, Makoto Toriyama, Tohru Yoshinaga
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Publication number: 20030183217Abstract: An insulator includes a coil side cylindrical portion extending from a plug side cylinder portion in a direction departing from a combustion chamber. One end of the coil side cylindrical portion protrudes in the direction departing from the combustion chamber with respect to a primary winding and a secondary winding. A pressure sensing element is disposed next to the one end of the coil side cylindrical portion. The signal lines of the pressure sensing element are taken out of a casing without passing aside an ignition coil. Thus, the diameter of the casing does not increase. The output signal of the pressure sensing element is not adversely influenced by discharge noises generated from the ignition coil.Type: ApplicationFiled: March 27, 2003Publication date: October 2, 2003Inventors: Tetsuya Miwa, Atsuya Mizutani, Takeo Maekawa, Hiromi Hiramatsu, Tohru Yoshinaga
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Publication number: 20030076111Abstract: A combustion condition detecting device detects combustion ions between opposing electrodes in a combustion chamber by ion current flowing between the electrodes in response to a.c. current voltage applied between the electrodes. A low pass filter for eliminating current components having high order frequencies of the a.c. voltage is disposed in a primary side of the transformer so that a waveform of the a.c. voltage approximates a sine wave. Thus, detection accuracy of the combustion ions is prevented from being affected by variation of capacitive current included in the current flowing between the electrodes, wherein the variation of the capacitive current is caused by distortion of the waveform of the a.c. voltage.Type: ApplicationFiled: October 15, 2002Publication date: April 24, 2003Inventors: Makoto Toriyama, Tohru Yoshinaga, Hiroshi Yorita
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Publication number: 20020145429Abstract: In an engine ignition unit, a transistor and a current detecting resistor are connected to primary and secondary windings of an ignition coil, respectively. The current detecting resistor is used for detecting a current flowing between the opposing electrodes of spark plug. At an ignition by the spark plug, high-frequency square wave signals are generated by an oscillator after an ignition signal is cut off. The square wave signals turn on and off the transistor. By this operation, a battery voltage is intermittently applied to the primary winding and an ion current is measured. A frequency of the square wave signals is set close to a resonant frequency of an ion current path including the spark plug, the secondary winding of the ignition coil and the current detecting resistor.Type: ApplicationFiled: April 4, 2002Publication date: October 10, 2002Inventors: Hiroshi Yorita, Masatoshi Ikeda, Makoto Toriyama, Tohru Yoshinaga
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Publication number: 20020108606Abstract: A power-saving type of ignition apparatus is provided with a spark plug of which electrodes (30, 40) are regulated in their shapes to lower an amount of energy required for its ignition. To face to a tip (31) of a center electrode (30) extending from a mounting bracket (10), a cylindrical protrusion (41) is built on one surface (43) of an earth electrode (40). The protrusion extends toward the center electrode to form a discharge gap (50) between the protrusion and the tip of the center electrode. Both of the tip of the center electrode and the protrusion of the earth electrode are 2.3 [mm] or less in each diameter (D1, D2), thus an amount of energy required for ignition being limited to 17 [mJ] or less.Type: ApplicationFiled: February 13, 2002Publication date: August 15, 2002Inventors: Tetsuya Miwa, Tohru Yoshinaga, Keiji Kanao, Shinichi Okabe
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Patent number: 6401691Abstract: A damping chamber is formed in a pressure relaxation device connected to a high pressure fuel pipe. Valve bodies are provided at openings of partitions, and a spring force is applied to the valve bodies by a spring in a valve closing direction. When a high pressure portion reaches an inlet of the damping chamber, the valve body opens to hold and absorb the high pressure portion in the damping chamber. When a low pressure portion reaches the inlet of the damping chamber, the high pressure portion held in the damping chamber is gradually released via a restricted orifice to cancel the low pressure portion, thereby reducing the pressure pulsation of fuel.Type: GrantFiled: October 22, 1999Date of Patent: June 11, 2002Assignees: Nippon Soken, Inc., Toyota Jidosha Kabushiki KaishaInventors: Takanobu Kawano, Tohru Yoshinaga, Katsuyuki Tanaka, Kenji Kanehara, Yoshihiro Nakase, Masaki Takeyama, Yoichi Sugiura, Katsuhiko Aoyama, Toshio Imamura
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Patent number: 6397827Abstract: An ignition device sets a total discharge period, each discharge period and each intermittent period of a multiple discharge are set by a control map in addition to the setting of a throttle opening, fuel injection timing, fuel injection period and ignition timing for the range of non-stratified charge combustion, when a direct injection-type engine operates in the range of stratified charge combustion. Ignition signals including a plurality of rises and falls are outputted in time with a specific ignition timing after fuel injection. Thus a plurality of sparks are generated from the spark plug, ensuring reliable ignition in response to changes in the concentration of sprayed fuel within the operation range for stratified charge combustion.Type: GrantFiled: July 31, 2000Date of Patent: June 4, 2002Assignee: Denso CorporationInventors: Takehiko Kato, Tohru Yoshinaga, Hiroshi Yorita, Shinichi Okabe, Tatsushi Nakashima, Tetsuya Miwa
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Patent number: 6265814Abstract: To excellently grow flame kernel while lowering breakdown voltage, a bypass electrode comprising a semiconductor material is installed in a path bypassing an inductive spark gap between a center electrode and a ground electrode, and the center electrode and the ground electrode are electrically connected by the bypass electrode and capacitive discharge is carried out by applying breakdown voltage between the center electrode and the ground electrode via the bypass electrode, and thereafter, inductive discharge is carried out through the inductive spark gap.Type: GrantFiled: August 28, 1998Date of Patent: July 24, 2001Assignee: Nippon Soken, Inc.Inventors: Tohru Yoshinaga, Takehiko Kato, Tokio Kohama, Hiroshi Yorita, Masaki Takeyama, Masatoshi Ikeda