| 摘要 |
PURPOSE:To improve heating efficiency for preventing freezing by providing a heating member on a valve disc of a valve for intake passage. CONSTITUTION:A heating member 13 made of positive temperature characteristic resistance element is buried in the surface of the circumferential part of a valve disc 12 for opening/closing an intake passage 11. A control switch 16 is turned on or off according to the rotary angle of the valve disc 12, and only when the opening degree of a valve for intake passage 10 is small, the control switch 16 is turned on, and electric current is applied to electric wires 15 and 17. Accordingly, in the state where the opening degree of the valve 10 is small and air flow flows in a narrow opening of the circumferential end part of the valve at a high speed and freezing is easily generated, the heating member 13 generates heat and heats the circumferential part of the valve disc 12 which is most easily forced. As above-mentioned, freezing can be prevented by directly heating the valve disc 12, and heating is efficient. Simplification and miniaturization of the heating member 13 is accordingly attempted, and precise temperature control can be realized. |
