Rational hardness ratio of fuel equipment parts under static loading

The definition of a rational combination of hardness of parts is necessary to determine the resource indicators of products. This task is also relevant for parts of internal combustion engines, including parts of their fuel equipment of any type. In operation such parts are used under constant contact. There is a wide distribution of fuel systems such as Common Rail in Russia. The high fuel pressure in the cavities of such systems exists both at the time of injection and between injections as well. The development of production of the domestic common rail fuel type system makes the task of determining the rational ratio of hardnesses even more important. Its solution is necessary, for example, for connecting high-pressure fuel lines with nozzle fittings, high-pressure pumps and fuel batteries. Engine manufacturers in some cases indicate in the operating instructions the maximum intervals for the use of certain components, for example, high pressure fuel lines. At the same time, there are practically no methodological materials allowing one to choose one or another hardness ratio. There are only a few attempts in this direction made in higher education institutions, for example, in the Polzunov Altai State Technical University. In this paper, an attempt is made to estimate the deformation of contact surfaces in «sphere-by-cone» type joints, which are typical for modern fuel equipment with various combinations of component hardness. The criterion for the rationality of the combination of hardness is the width of the contact trace - the residual deformation of parts. It is shown that when evaluating the rationality of fuel equipment manufacturers are guided by what component is more appropriate to replace in operation.

hardness, contact, cone, planted profile, fitting, fuel line