| 摘要 |
PURPOSE:To reduce noise in a system, in which an air door is driven by a d.c. motor, by gradually increasing the voltage impressed to the d.c. motor until the air door starts moving while it is being driven. CONSTITUTION:In a system which is arranged in an air duct and in which an air door to regulate the flow rate of the air passing a heater core is driven by a d.c. motor 5, a target location signal generator 1, which produces resistance value indicating the target location of the air door, is provided, and its output is sent to a microcomputer 3 via an A/D transducer 2. A location signal generator 6, which detects the true opening of the air door is provided, and its output is also sent to the microcomputer 3 via the A/D transducer 7. Both outputs are compared with each other in the microcomputer 3, and regulation is made in such a manner that a driving signal, which is gradually increased from the time of receiving the target location signal to the time of receiving the detecting signal produced after the d.c. motor 5 starts driving operation, is kept being sent to a driving circuit 8. |
