THE CHANGING NATURE OF DIESEL ENGINE FUEL FILTERS FOR HIGH PRESSURE COMMON RAIL (HPCR) DIESEL INJECTION SYSTEMS

摘要

Over recent years the world has gradually witnessed the introduction of diesel engines equipped with ad- vanced High Pressure Common Rail (HPCR) fuel injection systems. The introduction of new designs is primarily the result of new emission regulations, which now requires these engines to improve their overall performance and reduce harmful pollutants with the culmination of requirements being 2015 when all new diesel engines shall be rated to Tier 4. In order to reduce emissions, advanced HPCR injection systems operate at pressures in excess of 30,000 psi and in some designs, pressures approaching 40,000 psi can be achieved. These advanced systems are capable of multiple injection events per cycle and involve clearances between moving parts in the order of 1 -4 μm. For these reasons, HPCR systems are far less tolerant to contamination than previous Electronic Unit Injector (EUI) designs. This increased demand on diesel fuel cleanliness presents new challenges to engine based contamination control solutions and the fuel filters that are intended to protect the injector and high pressure pump from damage or failure. To protect HPCR components, much lower concentrations of fine particles and water need to be maintained within the fuel system than were previously accepted. This paper will discuss some of the challenges that are faced and provide recommendations to achieving the required reliability.