| 摘要 |
PURPOSE:To prevent the lowering of an efficiency due to incomplete combustion through proper control of the amount of the air to the amount of fuel supplied even at a time when suction is unbalanced with exhaust, by correcting driving of a motor in response to a signal from a fan drive current detector. CONSTITUTION:When balance between suction and exhaust is lost by an external factor such as sudden strong wind, a low pressure is applied on an exhaust port 11, and variation in fan drive exceeds tolerance alpha as shown in (b), deviation of the variation in fan drive is decided by a fan drive part 5. Further, in order to prevent the occurrence of erroneous decision, the fan drive part 5 verifies said condition for a specified decision time tau. If. after the judging time tau has elapsed, the variation in fan drive still exceeds the tolerance, and even if the number of revolutions to the amount of gas supplied is within a specified range, a motor 2 is driven so that the number of revolutions of a fan is increased by the fan drive part 5. This increase the number of revolutions of a fan, the amount of the air, and a theoretical air ratio, and thereby, the ratio enters into the range of tolerance beta, resulting in provision of a stable combustion condition. |
