| 摘要 |
The present invention provides a method of testing the cleanness of the inner surface of a high-pressure fuel injection pipe in which the cleanness of the inner surface of a high-pressure fuel injection pipe can be accurately measured with less variation and high reproducibility. In testing the cleanness of the inner surface of a high-pressure fuel injection pipe based on foreign particles collected by a filter for filtering a measuring liquid obtained by washing the inner circumferential surface of the high-pressure fuel injection pipe, at least the part of a group of measuring apparatuses used for testing the cleanness of the inner surface of the high-pressure fuel injection pipe that is in contact with the measuring liquid is washed using a washing solution comprising a solvent for dissolving foreign particles prior to the testing of cleanness. |
