Mazda Motor Corporation

Kuniaki Wada

Kouichi Miyamoto

Takafumi Nishio

Takahiro Yamamoto

Nobuhiko Yokoyama

Kenya Ishii

Tomohisa Handa

Takayoshi Fujita

Tomonobu Mizuba

When an engine rotation speed is lower than a reference rotation speed, first failure determination in which failure of a flow rate control valve is determined based on a pressure change of cooling water detected by a pressure sensor is executed, when a valve closing instruction to switch the flow rate control valve from an opened state to a closed state is output from a valve control device; and when an engine rotation speed is equal to or higher than the reference rotation speed, second failure determination in which failure of the flow rate control valve is determined based on a pressure change of cooling water detected by a pressure sensor is executed, when a valve opening instruction to switch the flow rate control valve from a closed state to an opened state is output from the valve control device.

Cooling device for engine, and failure determination method thereof

An apparatus for diagnosing lubricant degradation includes a soot amount estimator configured to estimate an amount of soot formed in a predetermined period in a combustion chamber of an engine, and diagnoses the degradation of a lubricant based on a cumulative value of the amount of soot estimated. The soot amount estimator calculates the amount of soot based on a speed of the engine and a load parameter related to a load of the engine, and corrects, based on a temperature parameter correlated to the temperature of the combustion chamber, the amount of soot calculated into an increased value if the temperature parameter is lower than a predetermined first temperature.

Apparatus and method for diagnosing lubricant degradation in internal combustion engine

Growing community of inventors

Hatsukaichi, Japan

Kuniaki Wada