Denso Corporation

Satoshi Nishimoto

Toru Itabashi

Nobuyuki Tanaka

Yuji Yamada

Ryoichi Shiraishi

Yuki Mikami

Masafumi Umeno

Hiroki Kakui

Yuji Iwama

An air-fuel ratio (A/F) sensor control device includes: an impedance detector detecting an impedance of an A/F sensor; and a pump current controller performing a digital control on a supply of electric current to the A/F sensor. The pump current controller includes a PID calculator calculating an instruction current value according to a difference of two input values, i.e., the difference between a PID control target value and a detection value of an inter-terminal voltage of a Nernst cell; and a protection clamper limiting a supply of electric current to a pump cell based on the instruction current value and the impedance. The protection clamper includes: a current clamp threshold calculator calculating an upper limit value and a lower limit value of the electric current based on the impedance of the Nernst cell, a first current value limiter limiting the instruction current value by the upper limit value and the lower limit value, and a second current value limiter performing a constant current limitation on an instruction current limit value by using an instruction constant current value.

Gas sensor controller

An air-fuel ratio sensor control unit connected with an air-fuel ratio sensor including a common terminal, a first terminal and a second terminal includes a common connection terminal connected with the common terminal, a first connection terminal connected with the first terminal, a second connection terminal connected with the second terminal, a voltage control circuit controlling a voltage of the first connection terminal, a resistor connected with the common connection terminal, a voltage sensing circuit sensing a two-end voltage of the resistor, a current applying circuit applying a constant current to the second connection terminal, and a determining unit sensing a change quantity of the two-end voltage by using the voltage sensing circuit and determining whether a disconnection failure of the first connection terminal occurs based on a sensing result of the change quantity.

Air-fuel ratio sensor control unit

A control apparatus that controls a gas concentration sensor includes a sweep circuit, a current detection resistor, and a calculation portion. The sweep circuit supplies the gas concentration sensor with a sweep current. The calculation portion calculates impedance of the gas concentration sensor. The gas concentration sensor and the current detection resistor are sequentially connected in series along a direction from the sweep circuit to a reference voltage. The sweep circuit has a constant voltage circuit and a reference resistor. An increasing and decreasing tendency of a manufacturing variation of the reference resistor and an increasing and decreasing tendency of a manufacturing variation of the current detection resistor are identical. The calculation portion divides a product of a resistance value of the current detection resistor and a time variation of applied voltage to the gas concentration sensor by a time variation of applied voltage to the current detection resistor.

Control apparatus

A load driving device includes a driving switching element, an interrupting part, a short-circuiting switching element, and a protecting element. The driving switching element drives a load by controlling energization to the load. The interrupting part is disposed on an energizing path to the load. The interrupting part is not melted by a driving current to the load and is melted by an interrupting current larger than the driving current so as to interrupt energization to the load. The short-circuiting switching element is connected in parallel with the load and applies the interrupting current to the interrupting part. The protecting element protects the short-circuiting switching element.

Growing community of inventors

Kariya, Japan

Satoshi Nishimoto