| 摘要 |
PURPOSE:To obtain a high adjusting ratio for combustion volume and provide a stable air fuel ratio by a method wherein each of the upstream side pressures of air throttle and gas throttle is alternatively sensed by a pressure sensor and an air volume control mechanism is controlled in such way as a difference between the output signals becomes zero. CONSTITUTION:In an air fuel ratio control circuit 31, an output from amplifier 32 for amplifying an output signal of a pressure sensor passes through a change- over switch 4 which is changed-over by a change-over signal generator 33, is fed to an air pressure analogue memory 34 and a gas pressure analogue memory 35 and then each of the values is stored and updated in synchroneous with the change-over signal. An electric current is fed to the solenoid coil 23 for the pressure change-over unit 17 from the change-over signal generator. A difference between the output signals from each of the memories 34 and 35 is multiplied and amplified by the number of rotation control circuit 36 and the number of rotation of the fan motor is controlled in a feed-back manner in such a way as the difference in the output signals from each of the memories 34 and 35 becomes zero. |
