Denso Corporation

Nippon Soken, Inc.

Toyota Jidosha Kabushiki Kaisha

Michiyasu Moritsugu

Eiichi Kurokawa

Takanao Tomura

Toshihiko Igashira

Keigo Mizutani

Shunichi Takeda

Hiroshi Yorita

Yoshiki Chujo

Daisuke Makino

A failure diagnosis device for an ignition circuit, comprising: an ignition plug; an ignition coil; a capacitor series connection including a high side capacitor and a low side capacitor; a switching-element series connection including a high side switching element and a low side switching element; an inter-terminal voltage detection unit for detecting an inter-terminal voltage of the capacitor series connection; an intermediate voltage detection unit for detecting an intermediate voltage at the connection point of the high side capacitor and the low side capacitor; and a determination unit for determining a failure location of the ignition circuit based on at least one of the inter-terminal voltage and the intermediate voltage.

Failure diagnosis device for ignition circuit

A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Fault detecting apparatus designed to detect different types of faults of gas sensor

A gas concentration measuring apparatus has a gas sensor consisting of pump, sensor, and monitor cells. The apparatus works to determine the value of voltage applied to the pump cell when a change in current produced by the monitor cell or the sensor cell changes upon a change in the voltage applied to the pump cell varies greatly and uses it to determine a control point to which the voltage applied to the pump cell is to be controlled. This keeps a gas concentration measuring accuracy free from, for example, aging of the sensor.

Gas concentration measuring apparatus designed to minimize measurement error

A gas concentration measuring apparatus has a gas sensor including pump, sensor, and monitor cells. The apparatus works to look up a predetermined voltage-to-current relation to determine an initial value to be applied to the pump cell as a function of a current output of the pump cell, apply the initial value of the voltage to the pump cell, and to sweep it temporarily. The apparatus works to correct the initial value of the voltage as a function of a current output of the sensor cell upon the sweep of the initial value of the voltage applied to the pump cell, thereby better maintaining gas concentration measuring accuracy with respect to, for example, aging of the sensor.

Gas concentration measuring apparatus minimizing measurement error

An oxygen concentration detecting apparatus having, a pumping cell and a sensing cell, electrodes formed on both surfaces of each of the pumping and sensing cells, a related support structure forming a closed space by being connected with the pumping and sensing cells, an opening communicating between the closed space and the surrounding environment, an electromotive force detector for detecting an electromotive force generated between the electrodes of the sensing cell, a voltage source for applying a voltage between the electrodes of the pumping cell, a current detector for detecting as a signal representing the oxygen concentration a current flowing in the pumping cell when a voltage is applied between the electrodes of the pumping cell, and a controller for controlling the voltage so that the electromotive force is constant at a specified value at which value the above-mentioned current is 70% or less of the limiting current.

Growing community of inventors

Okazaki, Japan

Michiyasu Moritsugu