Abstract: A filter abnormality determination system includes: an internal combustion engine having a plurality of cylinders; an exhaust passage connected to the internal combustion engine; a filter provided in the exhaust passage and opposed to the filter and outputting a detection value corresponding to an oxygen concentration in the exhaust gas; and a determination device, wherein the determination device includes a control unit that executes an imbalance control for controlling an air-fuel ratio of one of the plurality of cylinders to a value different from an air-fuel ratio of another of the plurality of cylinders; and a determination unit for determining whether the filter is abnormal based on a detection value of the sensor corresponding to an air-fuel ratio of an exhaust gas of the one cylinder during execution of the imbalance control.

Abstract: The inner surface of an oil passage in a member which is made as a die-cast formed product is made as a molded surface. By this structure, permeation of oil from the inner surface of the oil passage into the thickness portion of the member which is made as a die-cast formed product, and leakage thereof out to the exterior, is prevented.

Abstract: The inner surface of an oil passage in a member which is made as a die-cast formed product is made as a molded surface. By this structure, permeation of oil from the inner surface of the oil passage into the thickness portion of the member which is made a as a die-cast formed product, and leakage thereof out to the exterior, is prevented.