Denso Corporation

Nippon Soken, Inc.

Mazda Motor Corporation

Katsuhide Akimoto

Satoshi Hada

Takahito Masuko

Keigo Mizutani

Kenji Kato

Kazuhiko Miura

Takehiro Watarai

Shinya Teranishi

Shoichiro Emmei

Eiichi Kurokawa

Toshiyuki Suzuki

Masaaki Kato

Tomoo Kawase

Akira Fujii

Takafumi Nishio

Tooru Matsumoto

Yushi Fukuda

Takayuki Ishikawa

Tomofumi Fujii

Yuki Sato

Keita Takagi

Toshihide Kumazaki

Shuuichi Nakano

Tosihide Kumazaki

Ryo Teramoto

Tatsuhiro Ito

The control section of a control apparatus executes a first control for operating a voltage application section such as to cause a current to flow in a first direction through a gas sensor in a first period, and a second control for operating the voltage application section such as to cause a current to flow in a second direction, opposite to the first direction, through the gas sensor in a second period. The control apparatus changes the length of at least one of the first period and the second period based on a comparison between a first measurement value, which is the absolute value of a value measured by a sweep measurement section during execution of the first control, and a second measurement value, which is the absolute value of a value measured by the sweep measurement section during execution of the second control.

Control apparatus

A signal processing apparatus for a gas sensor is applied to a gas sensor that is disposed on an exhaust passage of an engine to detect a concentration of a specific component in exhaust gas flowing through the exhaust passage. The signal processing apparatus includes a filtering means that attenuates exhaust pulsation noise included in a detection signal of the gas sensor, and a filter characteristic setting means that variably sets filter characteristics of the filtering means based on engine speed.

Signal processing apparatus for gas sensor

A sensor element of an A/F sensor AS has a solid electrolyte layer, a first electrode arranged on one side of the solid electrolyte layer so as to be exposed to the exhaust gas of an internal combustion engine, and a second electrode arranged on the other side of the solid electrolyte layer so as to face an atmospheric air chamber. The sensor element generates a sensor output according to the oxygen concentration in the exhaust gas. A microcomputer supplies oxygen to the first electrode side from the second electrode side via the solid electrolyte layer by applying a predetermined voltage between the pair of electrodes of the sensor element. Moreover, the microcomputer determines a crack abnormality of the solid electrolyte layer based on electric current between the pair of electrodes which is generated with start of the oxygen supply.

Gas sensor control apparatus

A gas sensor control system for a gas sensor having a first, a second, and a third cell. The second cell produces a second cell electric current indicating the concentration of oxygen in gas in which the amount of oxygen has already been controlled by the first cell. The third cell produces a third cell electric current indicating the concentration of a preselected component of the gas in which the amount of oxygen has already been controlled by the first cell. A second cell circuit converts the second cell electric current into a voltage as a second cell current-measured value. A current adjuster produces a flow of an adjustment current as a function of the second cell current-measured value so that a third cell circuit converts the third cell electric current minus the adjustment current into a voltage as representing the concentration of the preselected component of the gas.

Gas sensor control system ensuring increased measurement accuracy

A gas sensing element is disclosed as having a measuring gas chamber to which measuring gases are admitted, a diffusion resistance portion for introducing measuring gases to the measuring gas chamber under diffusion resistance, a sensor cell for detecting a specified gas concentration of measuring gases, and an oxygen pump cell for adjusting an oxygen concentration in the measuring gases. The sensor cell includes a measuring electrode, placed facing the measuring gas chamber, and a reference electrode formed in pair with the measuring electrode. The oxygen pump cell includes an inner pump electrode placed facing the measuring gas chamber, and an outer pump electrode formed in pair with the inner pump electrode. The diffusion resistance portion is placed in an area inside of external end walls of the inner pump electrode to be exposed to the measuring gas chamber.

Gas sensing element with increased response

A gas sensor control device is disclosed as including a sensor cell having a negative terminal, to which a current-voltage converter is connected, and a differential amplifier is connected to the current-voltage converter to provide a current measured result applied to a microcomputer. The current-voltage converter has an opposite-to-sensor terminal to which another differential amplifier is connected. A sensor-side terminal of the current-voltage converter and another differential amplifier is electrically connected to each other via an electric pathway having a sensor-current flow disabling pathway in which a switch circuit is provided. Closing the switch circuit allows a potential difference between both terminals of the current-voltage converter is zeroed. With the switch circuit closed, the microcomputer calculates an element current correcting value, while detecting an electromotive force of the sensor cell based on which a failure is determined.

Gas sensor control device

A gas concentration measuring apparatus for use in air-fuel ratio control of automotive engines is designed to determine the concentration of oxygen within a wide and a narrow range using a sensor current flowing through a sensor element. The apparatus includes an amplifier circuit equipped with an operational amplifier and a plurality of amplifying resistors and a switch. The switch is responsive to a request signal to switch a relation in electrical connection between an operational amplifier and the amplifying resistors to distribute the amplifying resistors into an input resistor and a feedback resistor for the operational amplifier to change an amplification factor of the amplifier circuit. This results in a change in resolution of measurement of the concentration of oxygen, thereby ensuring enhanced accuracy in determining the concentration of oxygen in a selected one of the narrow and wide ranges.

Gas concentration measuring apparatus designed to enhance measurement accuracy in desired range

A fuel injection system includes (i) an injector for injecting gaseous fuel and liquid fuel into a cylinder of an internal combustion engine, (ii) a gaseous fuel supplying unit having a gaseous feel tank as a first high-pressure accumulating source for pressurizing gaseous fuel, (iii) a liquid fuel supplying unit having a common rail as a second high-pressure accumulating source for pressurizing liquid fuel; (iv) a fuel pump as a pressure feeding unit that pressure feeds liquid fuel to the common rail; and (v) a compressor as a pressure increasing unit, which is operated under pressure of the pressurized gaseous fuel to increase pressure of liquid fuel pressure fed from the fuel pump.

Fuel injection system

An apparatus for driving a discharge lamp includes a piezoelectric transformer connected to the discharge lamp. A drive device operates for feeding controllable power to the discharge lamp via the piezoelectric transformer to controllably drive the discharge lamp. A lighting control device operates for controlling the drive device to light the discharge lamp. In addition, the lighting control device operates for controlling the drive device to feed a first current to the discharge lamp during a build-up time interval before the discharge lamp changes to a stably lighting state. After the build-up time interval, the drive device is controlled to feed a second current to the discharge lamp. The first current is greater than the second current.

Discharge-lamp drive apparatus

A drive circuit supplies a FB feedback signal having a predetermined frequency to drive electrodes to vibrate a vibrator. An angular velocity detecting circuit detects a vibratory movement caused in a direction normal to an oscillating direction of the vibrator based on a sensing signal of angular velocity sensing electrodes, thereby generating an angular velocity signal. A signal input circuit supplies a diagnostic signal having a frequency different from that of the FB signal, which is entered into the vibrator via diagnosing electrodes. A diagnosis circuit generates a breakdown signal based on a signal responsive to the diagnostic signal which is obtained from at least one of the drive electrodes and the angular velocity sensing electrodes.

Angular velocity sensor and diagnosis system for this sensor

A drive circuit supplies a FB (feedback) signal having a predetermined frequency to drive electrodes to vibrate a vibrator. An angular velocity detecting circuit detects a vibratory movement caused in a direction normal to an oscillating direction of the vibrator based on a sensing signal of angular velocity sensing electrodes, thereby generating an angular velocity signal. A signal input circuit supplies a diagnostic signal having a frequency different from that of the FB signal, which is entered into the vibrator via diagnosing electrodes. A diagnosis circuit generates a breakdown signal based on a signal responsive to the diagnostic signal which is obtained from at least one of the drive electrodes and the angular velocity sensing electrodes.

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Nishio, Japan

Katsuhide Akimoto