Denso Corporation

Nippondenso Co., Ltd.

Hirofumi Shouda

Toshio Kondo

Hiroshi Haraguchi

Katsuhiko Kawai

Eijirou Yamada

Yoshihiko Hirata

An exhaust gas sensor for detecting oxygen concentration in exhaust gas is disposed in an exhaust pipe of an internal combustion engine. The sensor including a heater is controlled by a system that includes an electronic control unit. Water vapor contained in the exhaust gas is condensed on the sensor when the exhaust gas temperature is low. If the water condensation occurs while the sensor is heated by the heater, a sensor element may be cracked due to local cooling by the condensed water. To avoid the water condensation, the exhaust gas temperature is raised by retarding ignition timing of the engine for a certain period after the engine is started. After the exhaust gas is heated to a certain level, the sensor is heated. Alternatively, heating of the sensor is prohibited until the exhaust gas temperature becomes to a level at which no water condensation occurs. Thus, the cracking of the sensor element is avoided while making a delay of sensor activation minimal.

System for controlling exhaust gas sensor having heater

A temperature projecting system includes a temperature sensor for monitoring a temperature of an objective portion where the temperature changes depending on an engine operating condition. The temperature projecting system projects an actual temperature of the objective portion based on the monitored temperature but free of a first-order lag of the temperature sensor. A temperature control system includes the temperature projecting system. The temperature control system derives a correction amount for a basic control amount of an actuator based on a difference between the projected actual temperature and a target temperature. The basic control amount is corrected by the correction amount to derive a corrected control amount which controls the engine operating condition and thus the temperature of the objective portion.

Temperature predicting system for internal combustion engine and

Growing community of inventors

Toyota, Japan

Hirofumi Shouda