Denso Corporation

Nippondenso Co., Ltd.

Denso Corpora Tion

Masayuki Takami

Tomomichi Mizoguchi

Satoshi Haseda

Kazuhiro Okazaki

Koji Jono

Yukihiro Yamashita

Jun Hasegawa

Syuichi Nakano

Isao Aichi

Takafumi Hitotsumatsu

Shinji Niwa

Kunio Yokoi

Naoyori Tanzawa

Tooru Nada

Kazuhisa Suzuki

A voice recognition terminal executes a local voice recognition process and utilizes an external center voice recognition process. The terminal includes: a voice message synthesizing element for synthesizing at least one of a voice message to be output from a speaker according to the external center voice recognition process and a voice message to be output from the speaker according to the local voice recognition process so as to distinguish between characteristics of the voice message to be output from the speaker according to the external center voice recognition process and characteristics of the voice message to be output from the speaker according to the local voice recognition process; and a voice output element for outputting a synthesized voice message from the speaker.

Voice recognition terminal

An object-detecting device detects an operation object for operating an operating apparatus. The object-detecting device includes an imaging portion for imaging the operation object and an image processor for extracting the operation object. The operation object has a first face, on which outside light falls from outside into the operating apparatus, and a second face opposite to the first face. The imaging portion images the second face of the operation object. The object-detecting device can stably detect the operation object, even when an illuminance variation of outside light is large.

Object-detecting device and method of extracting operation object

A speech recognition apparatus includes a storage medium for storing tree structured dictionary data containing words as nodes in a tree structure with a root and leaf nodes. An input speech is compared with a forward acoustic model corresponding to a speech resulting from chronologically reproducing words indicated by nodes for leaf nodes. A backward speech is further compared with a backward acoustic model. The backward speech is generated by reproducing the input speech in chronologically backward order. The backward acoustic model corresponds to a speech resulting from reproducing a word string toward the root in chronologically backward order. The comparison is performed in the backward order of a sequence starting from one of separator nodes. The speech recognition apparatus thereby outputs a word string that highly likely matches the input speech.

Speech recognition apparatus and speech recognition program

A speech recognition (SR) dictionary switching unit selects a SR dictionary including commands that are for controlling target devices and selectable in current operating states detected by a device-state detecting unit. When a SR engine recognizes an uttered command of a user, it collates the speech with the commands included in the selected SR dictionary. If the command is not selectable in the current operating states of the target devices and is one of a reciprocal pair of commands working oppositely to each other, the other of the reciprocal pair is substituted for the command. This results in decreasing unreasonable and unpleasant feeling of the user in voice manipulation.

Voice control system substituting the oppositely-working command in a pair if the recognized command is not selectable for the given system state

A/F ratio sensor includes an element portion using a solid electrolytic layer, and generates a sensor current in proportion to an oxygen concentration in an exhaust gas when a voltage is applied thereto. A bias control circuit switches the voltage applied to the A/F ratio sensor to an element resistance detection voltage during an element resistance detection with a given time constant, and detects the sensor current flowing at that time. A comparing circuit detects an amount of voltage change reaching a given value. A timing decision circuit decides a detection of voltage and current changes during the decision timing of the comparing circuit. A data output circuit measures the current change relative to the voltage change in response to the timing decision of the timing decision circuit. In this apparatus, the voltage change and the current change are detected when the applied voltage, which change with the given time constant, reaches to the given reference voltage Vref. In other words, the amount of the current change &Dgr;I of the sensor current is detected before the voltage, which change with the given time constant, converges to the voltage V .

Method for detecting an element resistance of a gas concentration sensor and gas concentration detection apparatus

A sensor element of an A/F sensor is constructed to laminate and integrate a solid electrolyte and a heater. The A/F sensor outputs a linear A/F detection signal proportional to the oxygen concentration in exhaust gases, when voltage is applied. An ECU controls the heater through heater control circuit to keep the sensor element at a predetermined activation temperature. The ECU detects an element resistance on the basis of the voltage applied to the sensor element and sensor current caused by the applied voltage, and converts the element resistance to an element temperature. During the temperature increasing of the A/F sensor, the current supply to the heater is duty-controlled according to the element temperature changing rate (the temperature increasing rate of the sensor element). Accordingly, the temperature increasing characteristics of the sensor is satisfactorily maintained, and disadvantages such as an element cracking are prevented.

Gas component concentration measuring apparatus

A detecting unit of an oxygen sensor as an A/F sensor has a solid electrolyte layer and a diffusion resistance layer and generates a current value according to the concentration of oxygen in an exhaust gas by applying a voltage across electrodes on an exhaust gas side and an atmosphere side of the solid electrolyte layer. An oxygen supply/exhaust unit has a solid electrolyte layer and a pair of electrodes formed on both faces of the solid electrolyte layer, and supplies oxygen near to the electrode on the atmosphere side of the detecting unit or exhausts oxygen near the electrode. A control unit controls, in response to a limit current value detected by a current detection unit, the amount of supply or exhaust of oxygen of the oxygen supply/exhaust unit on the basis of the detected current value. A control target value of a current flowing in the solid electrolyte layer is variably set so that amount of oxygen moving in the solid electrolyte layers are equal, thereby controlling the amount of supply or exhaust of oxygen of the oxygen supply/exhaust unit.

Limit current type oxygen concentration detection having oxygen

An air-fuel ratio sensor generates linear air-fuel ratio detection signals proportional to concentration of oxygen in exhaust gas from an engine in response to a command voltage from a microprocessor. A bias command signal generated by the microprocessor is provided to a D/A converter which converts it to an analog signal. Thereafter, the signal is provided to an LPF for removing the high frequency components of the analog signal. Output voltage of the LPF is provided to a bias control circuit. A single AC signal which has a predetermined frequency and which is provided with a predetermined time constant (about 159 .mu.s) by the LPF is applied to the air-fuel ratio sensor. Element resistance of the air-fuel ratio sensor is detected based on the voltage of the AC signal and the change in the current level of the air-fuel ratio sensor caused by the application of the AC signal.

Method for accurately detecting sensor element resistance

An A/F sensor outputs a linear air-fuel ratio detection signal proportional to the oxygen concentration in an exhaust gas from an engine upon application of a voltage. A computer controls the applied-voltage in a stoichiometric control region, a lean burn control region, an atmosphere detection region and a rich control region to have a fixed value such that the change rate of the applied-voltage is reduced to be less than that in other regions. In addition, when changing the voltage applied to the A/F sensor, the computer variably sets the voltage change speed sequentially. Thus, the influence of the capacitive characteristic of the A/F sensor is eliminated.

Air fuel ratio detection using current-limited sensor with different

An A/F sensor is driven by a voltage applied thereto at a command issued by a microprocessor, outputting an A/F detection signal which is linearly proportional to the concentration of oxygen. The microprocessor controls the voltage applied to the A/F sensor to bring a current flowing through the A/F sensor to a predetermined value in a zone outside a predetermined air-fuel ratio detection zone. In this outside zone, the applied voltage is controlled in accordance with a characteristic different from a positive characteristic in a normal positive characteristic in a voltage-current relation. That is, in a rich zone outside the air-fuel ratio detection zone, the applied voltage is controlled so as to make the applied voltage approach a maximum value of the electromotive force of the A/F sensor. In a lean zone outside the air-fuel ratio detection zone, on the other hand, the applied voltage is controlled so as to make the applied voltage approach a minimum value of the electromotive force of the A/F sensor.

Oxygen concentration detection with sensor current limitation

To achieve change-over from detection of an internal resistance of an oxygen sensor S to detection of a threshold current effectively in a short time, a positive desired voltage for measuring a threshold current is applied to an oxygen sensor S to detect the threshold current and then a negative voltage for measuring a temperature is applied to the oxygen sensor S for a short time to detect an internal resistance of the oxygen sensor. After that, when the voltage applied to the oxygen sensor S is restored to a positive desired voltage for measuring the threshold current, by applying a voltage higher than this positive desired voltage temporarily to the oxygen sensor S, discharge or recharge of electric charges due to electrostatic capacitance components of the oxygen sensor S is completed quickly to reduce the time required for convergence to the threshold current when the voltage is changed. As a result, it is possible to reduce the time during which the threshold current cannot be detected.

Method and device for measuring oxygen concentration

An oxygen sensor has a detecting device unit for outputting a sensor current such as a limiting current of which a value is constant even though a sensing voltage applied to the oxygen sensor changes in a limiting current generating region and corresponds to an air-fuel ratio of a combustion gas and a heater for heating the detecting device unit to keep a resistance of the detecting device unit even though the oxygen sensor is degraded. When the sensing voltage is changed to a second sensing voltage of a resistance governing region, a current peak occurs in the sensor current, and a peak current value is detected. Because the peak current value decreases as the oxygen sensor is gradually degraded, when the peak current value is lower than a degradation judging value, it is judged that the oxygen sensor is degraded. Therefore, the diagnosis of the degradation of the oxygen sensor can be performed with a high accuracy.

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Hamamatsu, Japan

Masayuki Takami