Corrosion of Methanol to DC Pump and Suggestions for Improvement

Previous practical studies showed that the life of DC pumps substantially reduced when supplying methanol compared with supplying gasoline. To explore the reason,the fault statistics was made on a large number of damaged nethanol pumps,while the phenomenon and mechanism of the non-uniform corrosion between the positive and negative electrodes were analyzed from the point of electrochemical corrosion. A simple methanol pump test bench was designed and durability tests of methanol pumps were performed using the bench,the theoretical analysis was verified to be correct. The results show that a kind of electrochemical action,which was similar with cathodic protection,happened between the positive and negative circuit of the DC pump. This effect accelerated the corrosion of the positive line but protected the negative line at the same time. Based on this,testing and analyzing were made on both the integrated and separate electro-hydraulic pump. It is pointed out that separating both the positive and negative copper wires from the fluid for the electro-hydraulic integration pump is a feasible way to improve the methanol-resistant capability of the DC pump.