| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an air heater for an internal combustion engine capable of preventing abnormal rise in the temperature of a heater unit without fail and protecting the heater unit properly. <P>SOLUTION: A PWM unit 230 performs duty control of electric power supplied into the heater unit 100 by turning a semiconductor switch 232 on/off by a PWM circuit 231 based on instructions for heating from an ECU 210. A fuse 240 fused when performing continuous current carrying into the heater unit 100 being equivalent to duty-control by duty ratio of 100% to shut off current carrying into the heater unit 100 at abnormal time is provided. The PWM unit 230 performs the duty control by a duty ratio for preventing the fuse 240 from functioning usually. <P>COPYRIGHT: (C)2007,JPO&INPIT |
