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A simulation tester was designed which could be used to simulate the wear and vibration of the key rubbing pairs in an internal-combustion engine, such as cylinder liner-piston ring, crankshaft and sliding bearings. Its pivotal innovation is that high pressure air was adopted to simulate the explosive pressure and pressure evolution in a cylinder to accord with the real conditions. Pressure sensors, vibration accelerations sensors, oil monitoring sensors and temperature sensors were installed at many points and directions on the tester support to form an on-line condition monitoring system via the developed software, which could simultaneously monitor the real-time wear and vibration condition for key rubbing pairs in internal-combustion engine. It is believed that the successful application of the tester for both tribological and dynamic characterization will be very significant to study the key rubbing pairs in internal-combustion engine.

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Pressure safety valves (PSVs) are designed to provide ultimate protection for pressure systems. For design or optimization purpose, it is necessary to study the lift force exerted on the valve disk. Under special valve configuration, the lift force shows discontinuity with the increment of valve opening, which is an undesirable phenomenon because it may be the cause of some serious problems, such as unstable valve operations. To study their characteristics in depth, experimental investigations are conducted in this paper. For lift force measurement, an experimental rig was specially designed and built. A series of force tests were carried out, and the result indicates that two variables, namely, the position of the adjustment ring and the thickness of the valve nozzle, have great influence on lift force; under certain valve configurations, the lift force has a discontinuous performance; for different configurations, degrees and positions of force discontinuities are very different; lift forces are linear functions of the inlet pressures, and the slopes of the force changes are similar for different valve openings.