| 摘要 |
PURPOSE:To keep combustion in good condition, by maintaining the concentration of carbon dioxide in exhaust gas constant through regulating air supplied to a combustion chamber corresponding to the detected quantity of carbon dioxide in the exhaust gas. CONSTITUTION:If the concentration of carbon dioxide in exhaust gas exceeds a set value, the internal resistance of a detecting element 9 exceeds a set value, and the output of a comparator 50 becomes low level and switches off a transistor 45. Then the input level of a transistor 40 becomes comparatively high, and so the current amplification factor of a Darlington circuit 37 which is controlled to make the internal impedance of a transistor 40 low is controlled to become low. Therefore, current through a feed and exhaust fan motor 8 is controlled to the decreasing direction, i.e. to the direction of decreasing the revolution of the feed and exhaust fan motor. |
