Abstract: 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.

Abstract: In a chain device of an engine which comprises a driving sprocket at a cylinder block, a driven sprocket at a cylinder head, and a timing chain, there are provided a chain guide which supports the timing chain and a support member which supports the chain guide, the chain guide comprises a fastening portion which is fixedly fastened to the cylinder head and a slide support portion which extends toward a side of the cylinder block beyond a boundary between the cylinder block and the cylinder head, and the support member is configured to slidably contact a front-surface lower portion of the slide support portion.

Abstract: 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.