Investigation of electrical fuel – injection pump characteristics of petrol engines in simulation of basic fuel system problems

Abstract

Technical state of electrical fuel-injection pumps of automobiles with petrol engines was evaluated with application of a multiple factor experiment, based on diagnostics test modes. There exist two main problems in the fuel system, connected with the fuel volume being injected into the fuel rail: clogging when the fuel flow to the rail and next to nozzles is hindered, wear out of elements in the pump part (due to an increasing clearance space between fuel-injection pump pulleys and casing the fuel flows over the tank, i.e., does not enter the system in sufficient volume). The studies showed that in the first case of fuel system problems the pump power circuit draws the current 4,6 А persistently depending on clogging extent. Such current rate is necessary for keeping high rotations of the pump elements, helping the pump to push through the necessary fuel volume into the fuel rail, making the essential pressure 310 кПа. In the second case the fuel does not enter the rail in sufficient amount either, but the current rate here is small (even smaller than the nominal reading). For example, in the largest fuel leakage it equals 2,5 A, power voltage being 12,5 V. The results and methods of experimental data treatment with MathCAD application are presented. The article materials are applicable for research, repair, technical maintenance organizations when they estimate technical state of fuel-injection low-pressure pumps ( including those which are installed on engines with microprocessor control system).