A study on optimal design and fatigue life of the common rail pipe

Abstract

To support the latest automobile technology, the next generation of diesel engines is expected to require higher injection pressures than the third generation which can operate at high injection pressures up to 1,800bar. A component in the common rail system, the common rail pipe must have higher strength because it is directly influenced by the high-pressure fuel. Preform design is very important for preventing the head of the common rail pipe from folding in the heading process. In this study, the angle, curvature and outer diameter of the die and the length of the trapped part are selected as main parameters in the design of the optimal preform shape that minimizes the radius of folding. The optimal design is carried out by finite element analysis and the Taguchi method using the main parameters and then fatigue-life analysis is preformed for predicting fatigue life according to the amount of folding. Also, a closed form equation to predict fatigue life was suggested by Goodman theory and life-prediction method for pressure vessels pursuant to ASME Code. In order to verify the reliability of common rail pipe, fatigue-structural coupled field analysis is performed. The results of the finite element analysis were in good agreement with those of the experiments at the actual site and theoretical analysis.

Design of Common Rail Fuel Pipe for High Pressure Direct Injection Natural Gas Engine in Marine Cylinder

“…Yigao Ning, et al [1][2] studied the processing and optimization of common rail pipe by means of finite element analysis method and proposed reasonable solutions. Xiang Wang et al [3][4][5] analyzed the design idea and technical scheme of common rail system by combining performance simulation calculation and test verification. Catania et al [6] developed a mathematical model to support experiment, layout and control design as well as performance optimization based on Numerical Simulation of common rail injection system dynamics, and verified the accuracy of the mathematical model on a high-performance test bench.…”

Modal properties diagnostics of the high-pressure fuel injection pipes in off-road diesel engine

“…In the study described in [5,6], the manufacturing process of the injection pipe head intended for Common Rail systems is analysed in detail. In the first phase of study, it was found that the optimal design of pre-form punch and two-stage heading process significantly contribute to the improvement of fatigue life.…”

Mechanisms of fold formation during flange upsetting of tubular parts

“…During flange upsetting of tubular parts annular folding is commonly known as a process limit (FIGURE 1a) [2][3][4][5][6][7][8] mainly affected by the unsupported free length of the tubular part leading to buckling behavior during forging. Shafts do often have flanges to feed in or to pass torque or are used as bearing seat requiring sufficient mechanical strength therefore folding is not tolerated leading to a significant weak point of the part.…”