Failure Analysis of the Pin Bore of the Combined Piston for the Aero Engine

Abstract

The combined piston can be used in an aero piston heavy fuel engine because of its light weight, so as to reduce the reciprocating inertia force and improve the engine power-weight ratio. However, the pin bore of the combined piston is prone to deform leading to the failure of the piston. Based on the structure of the piston, the stress of the piston under thermomechanical coupling is analyzed, the temperature field of the piston is determined by experiments, and the deformation rule of the piston pin bore under the thermomechanical coupling is summarized. A design scheme is proposed to change the position of the thread connection between the piston crown and the piston head. Under the same conditions, the deformation of the piston pin bore of the original scheme and the new scheme is analyzed. The results show that together with the changing of the connection thread between the piston crown and the piston head, the deformation of the piston pin bore decreases by 60 μm and the deformation of the piston pin bore is controlled. The test results show that the deformation of the pin bore is within the acceptable range, which proves the effectiveness of the improved scheme.

Building a mathematical model of the destruction of a connecting rod-piston group in the car engine at hydraulic lock

“…After calculating the specific pressure on the skirt using (24), the results obtained were compared with the limit value of the specific pressure on the skirt of 7.2 MPa given in chapter 4. Similarly, for the piston pin, the maximum stress was 700 MPa.…”

“…It can be assumed [24] that the deformation of the piston under load from excessive pressure in the cylinder occurs in the direction opposite to the bending deformation of the pin (Fig. 7).…”

“…Fig. 8 shows the results of the calculation of specific pressures based on (24) with all the data and conditions specified above. The result (Fig.…”

Structural efficiency of block for aviation piston heavy fuel engine

“…In the design process of aviation heavy fuel piston engine, under the influence of compression ignition mode and under high cylinder pressure, the engine block needs to overcome the explosion pressure and high temperature generated during engine operation, and the body needs good strength and stiffness to ensure the safety and reliability of the engine (Pan and He, 2015). At present, the conventional method to enhance the engine block stiffness is to enhance the body wall thickness or replace high-strength materials, but replacing the lightweight high-performance materials will increase the cost of the engine (Pan and Guo, 2019; Pan et al , 2019), usually choose to increase the thickness or use cast iron materials to improve the stiffness. As the engine needs to carry the aircraft to fly off the ground, reducing the weight of the engine can reduce the weight of the aircraft.…”