Statistical Experimentation of Fuel System O-Ring Interface

O-rings are regularly utilized as a means of creating a seal between two components. Since the introduction of mini-concentric fuel pressure regulators, several issues have arisen related to assembly. In many cases, severe leaks are masked by lubricants used to aid in assembly. A lubricant is required which will not mask such leaks. The purpose of this study is to determine the impact on assembly between alcohol and oil based lubricants and to determine the optimum assembly parameters when using alcohol lubricants. Several variables were identified as being major contributors to the assembly process. A total of 6 variables were chosen to be examined as well as 2 noise factors. Each variable, or factor, was assigned several levels for this experiment. Several measurables were defined outputs from the experiment. To maximize the efficiency of testing, an orthogonal array was used to structure the experiment. An L18 orthogonal array was chosen composed of 72 trials. When conducting a trial, the CNC press was used to control insertion rate. Insertion force data was collected electronically by the CNC press controller. After assembly each sample was leak tested using an air pressure test. Samples were then disassembled to search for and examined O-ring damage. Upon completing the study, only one assembly process parameter was found to be significant for successful assembly. The dominant process parameter was found to be the assembly lubricant with a 70% alcohol based 30% water mixture being the optimum.