| 摘要 |
PURPOSE:To suppress drop of temperature because of sticking of the fuel by controlling the time of current application so that the plug temperature will become constant which is sensed during out of current application after the current is applied for a certain while. CONSTITUTION:When a relay RL is actuated for the purpose of current application, the output from a comparator CMP becomes at H, and an FF circuit, at the same time, is reset to drive a timer TM. After a certain specified time t, the FF is set to deactuate the RL, and thus the current to the plug GP is shut off. The Q output of the FF, at this time, becomes at H to reset the timer TM, and then temperature sensing for the GP is carried out by a bridge circuit BRG. If the reference value is not attained, the CMP output of the comparator becomes at H to drive the timer TM. Then, during out of current application under which the GP temperature exceeds the reference value, the CMP output continues to be at L until below the reference value is attained through temperature sensing with the BRG circuit, and thus no current is applied. When, thereafter, the GP temperature becomes below the reference value, the actions described above are repeated. |
