A tensioner device 14 for an engine 1 comprises a support member 16, a blade shoe 17 coming into sliding contact with a timing chain 11 having a base end section 17a held by a cylinder block 3 and a tip end section 17b supported by the support member 16, and a leaf spring 18 held by the blade shoe 1 for pressing the blade shoe 17 against the timing chain 11 elastically. The oscillator includes an input coupler optically aligned with the pump source and a multimode optical fiber optically coupled to the input coupler. The short terminal is coupled to a ground terminal. A liquid backflow is drawn off from the lower region of the direct contact cooler.