US6193211 Motor-operated flow control valve and gas recirculation control valve for internal combustion engine
Cited prior art · Youichi Watanabe, Yasuyuki Nakano and 4 more · United States · 2001
intake pipe side of the internal the Secondary vibration frequency of rotation of a 4-cycle combustion engine. Page 7 An orifice member 3 is Screwed into the gas passage A hole