Detection of Micro-capacitance Parameters Based on AC of ECT System

Parameters of micro-capacitance based on AC of ECT system was studied by theoretical analysis and experimental research.The theoretical analysis shows that the reduction of Cf can improve the sensitivity,and give the relationship between diesel fuel injection quantity and capacitance increment;2 pF and 1 pF were separately given to Cf for experimental research,and the theoretical and experimental values were separately 3.77 V/pF,3.68 V/pF and 7.54 V/pF,7.46 V/pF,and the linear correlation,resolution and stability were separately 0.999 6 and 0.999 8,0.194 fF and 2.59×10-5 pF / h.