Patents by Inventor Fuyuki Maehara
Fuyuki Maehara 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: 7180272Abstract: An apparatus is provided for detecting a malfunction in an on-vehicle charging system provided with a generator driven by an engine and a battery connected with the generator via a charging line. The apparatus comprises a first control unit controlling a generated condition of the generator and including a first voltage detector detecting a voltage generated by the generator and a second control unit including a second voltage detector detecting a voltage across the battery. The apparatus further comprises a communication device communicating, in the form of digital signals, via a communication line between the first and second control units, information about both the generated voltage and the battery voltage and a malfunction determination unit determining whether or not a malfunction occurs in the charging system on the basis of the communicated information.Type: GrantFiled: April 14, 2005Date of Patent: February 20, 2007Assignee: Denso CorporationInventors: Hideto Okahara, Tadatoshi Asada, Fuyuki Maehara
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Patent number: 7170263Abstract: An apparatus for controlling an on-vehicle generator is provided. The apparatus comprises a switching element, current detecting unit, setting unit and driving unit. The switching unit turns on/off an exciting current to an exciting winding of the generator, the switching element being driven responsively to a driving signal having an adjustable duty ratio. The setting unit sets the duty ratio based on (i) a difference between an output voltage of the generator and a target voltage value and (ii) a condition in which an electric load is disconnected from the generator, wherein the duty ratio is allowed to lower than a minimum value of the duty ratio depending on a generated state of the generator. The minimum value allows the exciting current to flow at a lower limit detectable by the current detecting unit, The driving unit drives the switching element based on the driving signal.Type: GrantFiled: February 21, 2006Date of Patent: January 30, 2007Assignee: Denso CorporationInventors: Takaaki Yamamoto, Fuyuki Maehara
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Publication number: 20060238172Abstract: A control apparatus for a vehicle generator includes a switch, a regulator, a fault condition detector, and a PWM signal generator. The switch is selectively turned on and off so as to intermittently excite the generator. The regulator controls on/off operation of the switch so as to bring an output of the generator into agreement with a target value. The fault condition detector detects a fault condition of the generator. The PWM signal generator generates and outputs a PWM signal that has a duty determined as a function of a duty of the on/off operation of the switch and a frequency determined based on if the fault condition of the generator is detected by the fault condition detector. Consequently, the control apparatus can inform an external control apparatus of the duty of the on/off operation of the switch and the fault condition of the generator with the single PWM signal.Type: ApplicationFiled: April 24, 2006Publication date: October 26, 2006Applicant: DENSO CORPORATIONInventors: Fuyuki Maehara, Kazuyuki Watanabe
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Patent number: 7106029Abstract: A vehicle generating system includes a generator for a vehicle, a voltage regulator that supplies field current to the field coil at a variable duty ratio, a field current sensor that detects field current amount, a signal transmitting circuit that transmits a signal representing the detected field current amount and the duty ratio and an electronically controlling unit that receives the signal representing the detected field current amount and the duty ratio and controls the engine according to one of the detected field current amount and the duty ratio.Type: GrantFiled: February 23, 2005Date of Patent: September 12, 2006Assignee: Denso CorporationInventors: Takatoshi Inokuchi, Fuyuki Maehara, Tadatoshi Asada
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Publication number: 20060197346Abstract: An apparatus for controlling power generation of a generator has a voltage detector and a power controller. The voltage detector detects a voltage of electric power generated in the generator. When receiving a first power control signal, the power controller controls the generator to maintain the detected voltage at a first target value. When receiving a second power control signal, the power controller controls the generator such that the power controller suppresses the power generation of the generator based on a difference between a value of the detected voltage and a second target value lower than the first target value so as to maintain the detected voltage at a predetermined value lower than the first target value. Therefore, even when the power generation is suppressed, pulsation of the generated electric power can be appropriately restrained.Type: ApplicationFiled: February 23, 2006Publication date: September 7, 2006Applicant: Denso CorporationInventor: Fuyuki Maehara
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Patent number: 7098628Abstract: A generation control system for a vehicle includes an ac generator, a field current control unit that controls the duty ratio of field current of the ac generator, a field current detector, a load current detector, a generator rotation speed detector, a driving-torque-increase calculator that calculates a predicted increase in driving torque of the ac generator from increase in the current supplied to an electric load. The driving-torque-increase calculator includes first output current calculator that calculates present output current of the ac generator from the generator's rotation speed and the field current and second output current calculator that calculates predicted output current of the ac generator from the first output current and the increase in the current supplied to the electric load. A predicted increase in driving torque of the ac generator is calculated from a difference between the present driving torque and a driving torque that corresponds to the predicted output current.Type: GrantFiled: December 9, 2004Date of Patent: August 29, 2006Assignee: Denso CorporationInventors: Fuyuki Maehara, Tadatoshi Asada
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Publication number: 20060186863Abstract: An apparatus for controlling an on-vehicle generator is provided. The apparatus comprises a switching element, current detecting unit, setting unit and driving unit. The switching unit turns on/off an exciting current to an exciting winding of the generator, the switching element being driven responsively to a driving signal having an adjustable duty ratio. The setting unit sets the duty ratio based on (i) a difference between an output voltage of the generator and a target voltage value and (ii) a condition in which an electric load is disconnected from the generator, wherein the duty ratio is allowed to lower than a minimum value of the duty ratio depending on a generated state of the generator. The minimum value allows the exciting current to flow at a lower limit detectable by the current detecting unit, The driving unit drives the switching element based on the driving signal.Type: ApplicationFiled: February 21, 2006Publication date: August 24, 2006Applicant: DENSO CORPORATIONInventors: Takaaki Yamamoto, Fuyuki Maehara
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Patent number: 7009366Abstract: A voltage regulator for an automotive alternator includes a switching transistor that controls an amount of field current supplied to a field coil of the alternator. The switching transistor is controlled in an ON-OFF fashion, and output voltage of the alternator is always monitored by a detector circuit that detects disconnection in a circuit for charging an on-board battery with the output voltage. It is determined that the disconnection occurred when a difference between the output voltage at a time when the switching transistor is turned off and the output voltage at a time when the switching transistor is turned on exceeds a predetermined value.Type: GrantFiled: January 30, 2004Date of Patent: March 7, 2006Assignee: Denso CorporationInventor: Fuyuki Maehara
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Publication number: 20050242784Abstract: An apparatus is provided for detecting a malfunction in an on-vehicle charging system provided with a generator driven by an engine and a battery connected with the generator via a charging line. The apparatus comprises a first control unit controlling a generated condition of the generator and including a first voltage detector detecting a voltage generated by the generator and a second control unit including a second voltage detector detecting a voltage across the battery. The apparatus further comprises a communication device communicating, in the form of digital signals, via a communication line between the first and second control units, information about both the generated voltage and the battery voltage and a malfunction determination unit determining whether or not a malfunction occurs in the charging system on the basis of the communicated information.Type: ApplicationFiled: April 14, 2005Publication date: November 3, 2005Applicant: Denso CorporationInventors: Hideto Okahara, Tadatoshi Asada, Fuyuki Maehara
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Publication number: 20050206350Abstract: A vehicle generating system includes a generator for a vehicle, a voltage regulator that supplies field current to the field coil at a variable duty ratio, a field current sensor that detects field current amount, a signal transmitting circuit that transmits a signal representing the detected field current amount and the duty ratio and an electronically controlling unit that receives the signal representing the detected field current amount and the duty ratio and controls the engine according to one of the detected field current amount and the duty ratio.Type: ApplicationFiled: February 23, 2005Publication date: September 22, 2005Applicant: DENSO CORPORATIONInventors: Takatoshi Inokuchi, Fuyuki Maehara, Tadatoshi Asada
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Publication number: 20050140143Abstract: A control apparatus such as an ECU, that controls the generator of a vehicle, measures the engine rotation speed and generator rotation speed while the engine is idling, and calculates and stores the ratio of the speed values. Thereafter when the vehicle is being driven and the current value of generator rotation speed is required, it is calculated based on the stored ratio value and the currently measured speed of the engine. The processing load on the ECU is thereby reduced, since generator rotation speed measurement processing is performed only in the idling condition.Type: ApplicationFiled: December 21, 2004Publication date: June 30, 2005Applicant: DENSO CORPORATIONInventors: Tadatoshi Asada, Fuyuki Maehara
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Publication number: 20050140342Abstract: A generation control system for a vehicle includes an ac generator, a field current control unit that controls the duty ratio of field current of the ac generator, a field current detector, a load current detector, a generator rotation speed detector, a driving-torque-increase calculator that calculates a predicted increase in driving torque of the ac generator from increase in the current supplied to an electric load. The driving-torque-increase calculator includes first output current calculator that calculates present output current of the ac generator from the generator's rotation speed and the field current and second output current calculator that calculates predicted output current of the ac generator from the first output current and the increase in the current supplied to the electric load. A predicted increase in driving torque of the ac generator is calculated from a difference between the present driving torque and a driving torque that corresponds to the predicted output current.Type: ApplicationFiled: December 9, 2004Publication date: June 30, 2005Applicant: DENSO CORPORATIONInventors: Fuyuki Maehara, Tadatoshi Asada
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Publication number: 20050135133Abstract: A generator control apparatus, for controlling electrical generation operation of a vehicle alternator, has a LAN circuit and a dedicated communication circuit, respectively communicating with an external control apparatus (e.g., engine ECU) via a LAN and via a dedicated signal line. When a selection signal is transmitted from the external control apparatus, designating a specific signal to be transmitted to or from the generator control apparatus, communication of that signal is performed via the dedicated signal line, enabling TDM communication of plural signals via the LAN concurrent with direct communication of a specific signal via the dedicated signal line.Type: ApplicationFiled: December 8, 2004Publication date: June 23, 2005Applicant: Denso CorporationInventor: Fuyuki Maehara
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Patent number: 6900618Abstract: A vehicle power generation control apparatus that has a power supply circuit, a rotation detecting circuit, an exciting current detecting circuit, an exciting current control circuit, a torque detecting/maximum exciting current determining circuit and a power transistor. When a speed of rotation of a vehicle generator is detected by the rotation detecting circuit and an exciting current flowing through an exciting winding of the vehicle generator is detected by the exciting current detecting circuit, the torque detecting/maximum exciting current determining circuit calculates an upper limit value of the exciting current so that a rate of change of a generator torque does not exceed a predetermined value, and the exciting current control circuit controls the exciting current so that the exciting current becomes below the limit value. This can prevent the engine revolution from becoming unstable due to variation of load or variation of engine revolution.Type: GrantFiled: March 11, 2003Date of Patent: May 31, 2005Assignee: Denso CorporationInventor: Fuyuki Maehara
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Publication number: 20040183514Abstract: A voltage regulator for an automotive alternator includes a switching transistor that controls an amount of field current supplied to a field coil of the alternator. The switching transistor is controlled in an ON-OFF fashion, and output voltage of the alternator is always monitored by a detector circuit that detects disconnection in a circuit for charging an on-board battery with the output voltage. It is determined that the disconnection occurred when a difference between the output voltage at a time when the switching transistor is turned off and the output voltage at a time when the switching transistor is turned on exceeds a predetermined value.Type: ApplicationFiled: January 30, 2004Publication date: September 23, 2004Applicant: DENSO CORPORATIONInventor: Fuyuki Maehara
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Patent number: 6777905Abstract: A voltage regulator controls an output of an automotive alternator by controlling an amount of excitation current supplied to a field winding of the alternator. The amount of the excitation current is sensed by a sensing resistor as a sensed voltage appearing across the sensing resistor. The sensed voltage is amplified by an amplifier to obtain a detected voltage, an amplifying factor of which is adjusted based on an reference voltage precisely corresponding to the amount of the excitation current, and thereby the detected voltage is equalized to the reference voltage. In this manner, the excitation current is precisely detected without mechanically adjusting a resistance of the sensing resistor by function-trimming or the like.Type: GrantFiled: October 4, 2002Date of Patent: August 17, 2004Assignee: Denso CorporationInventor: Fuyuki Maehara
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Publication number: 20040135374Abstract: A generator control system of a vehicle generator includes a switching element which turns on or off field current, a field current detecting circuit, a calculating circuit which calculates an average value of the field current when the switching element turns on according to an amount of the detected field current, and a switch control circuit which cyclically controls the switching element according to the average value and a limit value of the field current.Type: ApplicationFiled: December 17, 2003Publication date: July 15, 2004Applicant: DENSO CORPORATIONInventor: Fuyuki Maehara
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Patent number: 6707275Abstract: A voltage regulator of an automotive generator has a MOS transistor, flywheel diode, voltage detection circuit, and booster circuit. When a battery terminal voltage is below a voltage adjustment setting, current is supplied by a current supply circuit separate from a charge pump circuit to raise a gate voltage of the MOS transistor until the source voltage of the MOS transistor becomes greater than the reverse bias voltage of the flywheel diode, and the charge pump circuit output is applied to the MOS transistor after this specified value is reached. The charge pump circuit has an even number of capacitor stages.Type: GrantFiled: August 29, 2001Date of Patent: March 16, 2004Assignee: Denso CorporationInventors: Hideto Okahara, Fuyuki Maehara, Toshinori Maruyama
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Publication number: 20030178973Abstract: In a vehicle power generation control apparatus comprising a power supply circuit, a rotation detecting circuit, an exciting current detecting circuit, an exciting current control circuit, a torque detecting/maximum exciting current determining circuit and a power transistor, when a speed of rotation of a vehicle generator is detected by the rotation detecting circuit and an exciting current flowing through an exciting winding of the vehicle generator is detected by the exciting current detecting circuit, the torque detecting/maximum exciting current determining circuit calculates an upper limit value of the exciting current so that a rate of change of a generator torque does not exceed a predetermined value, and the exciting current control circuit controls the exciting current so that the exciting current becomes below the limit value. This can prevent the engine revolution from becoming unstable due to variation of load or variation of engine revolution.Type: ApplicationFiled: March 11, 2003Publication date: September 25, 2003Applicant: DENSO CORPORATIONInventor: Fuyuki Maehara
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Patent number: 6614207Abstract: A vehicular power generator control apparatus includes a switching transistor, a voltage control circuit, a high rotation speed detecting circuit, a leakage detecting circuit and a maximum conduction rate restricting circuit. The leakage detecting circuit detects leakage current flowing to a P-terminal. When the leakage current is detected, a maximum conduction rate set by the maximum conduction rate restricting circuit is changed from a small value at low rotation speeds to a large value. Thereby, field current flowing in a field coil is increased, a large voltage is generated at stator coils and current flows to a rectifying circuit to thereby reduce the leakage current which flows to the P-terminal.Type: GrantFiled: September 28, 2001Date of Patent: September 2, 2003Assignee: Denso CorporationInventors: Fuyuki Maehara, Keiji Takahashi, Toshinori Maruyama