Developing technology of creating wear-resistant ceramic coating for internal combustion engine cylinder sleeve

This paper presents the results of testing a wear-resistant ceramic coating on the work surface of an internal combustion engine (ICE) cylinder’s sleeve. A combined coating formation technology is described that consists in applying an aluminum layer to the sleeve’s work face by gas dynamic spraying and then covering this face with a ceramic layer by microarc oxidation (MAO). A tenfold reduction in the reinforced sleeve has been determined by the accelerated comparative wear rig tests of reference (new) sleeve-piston ring coupling specimens and reinforced specimens with a combined coating. The supplementation of nanoparticle admixture to MAO coating reduces the friction factor between the cylinder sleeve face and the piston ring by 25-30%. The proposed technology can be used to reinforce work surfaces of new cylinder sleeves and recover worn out ones.

Performance Comparison of Aerospace High-Temperature Resistant Ceramic Fiber Felt

Be aimed at the development and application of aerospace high-temperature resistant ceramic fiber felt, in this paper, as the common ceramic fiber felt in the field of high temperature resistance, quartz fiber felt, high silica fiber felt and mullite fiber felt were compared. The microstructure, thermal insulation, temperature resistance and mechanical properties were analyzed respectively, the performance advantages and disadvantages of three kinds of ceramic fiber felt were given, and its internal causes were studied. The results show that, the temperature resistance of mullite fiber felt is better than that of quartz fiber felt and high silica fiber felt, mainly due to its polycrystalline mullite structure, the thermal insulation performance of mullite fiber felt and high silica fiber felt is better than quartz fiber felt at high temperature, mainly due to the thermal reflection of polycrystalline mullite and the small pore structure of high silica fiber felt, the compressibility of quartz fiber felt is better than high silica fiber felt and mullite fiber felt.

Diagnosis of Defective Rotor Bars in Induction Motors

This paper proposes a diagnosis method, combining signal analysis and classification models, to the rotor defect problems of motors. Two manufacture technologies, nonmagnetic high-temperature resistant ceramic adhesive and electrical discharge machining (EDM), are applied to make testing samples, including blowhole and perforation defects of rotor bars in this study. The typical multiresolution analysis (MRA) model is used to analyze acquired source current signals of motors. The features are extracted from the signals of each column of MRA-matrix, including maximum, mean, standard deviation, root-mean-square, and summation. The typical back-propagation neural network (BPNN) model is used to diagnose the rotor bar defects of motors, and then the various signal-to-noise ratio (SNR) of white Gaussian noise (WGN), 30, 25, and 20 dB, are added to the signals to verify the robustness of the proposed method. The results show the availability of the proposed method to diagnose the rotor bar defects of motors.