摘要 |
<p>In order to detect the presence of a piston ring [5, 6, 7] in a piston engine, an ultrasonic beam produced by a transducer [8] is directed through the cylinder block [1] into a cylinder. The piston [2] and piston rings are moved in the cylinder through the ultrasonic beam, and reflected or transmitted ultrasonic signals are examined for amplitude peaks which occur when the piston rings are in the ultrasonic beam. Thus, the presence of piston rings can be checked without having to dismantle the engine.</p> |