Applied Mechanics and Materials Vols. 190-191

Abstract: The effects of butanol-diesel blending ratio, injecting timing and pilot injection quantity on combustion and emissions were experimentally investigated for a passenger car diesel engine. The results showed that under the typical operating condition of 2000r/min engine speed and 0.2MPa BMEP engine load, the engine’s combustion phase retarded, the peak combustion pressure and maximum in-cylinder mean temperature decreasing with the delay of the main injection timing using both the neat diesel and diesel-butanol blends. And the engine smoke level increased, while the NOx and CO emissions decreased. However, at the same main injection timing, with the increase of the butanol in the blends, the ignition delay of the combustion prolonged, the burn rate and brake specific fuel consumption increased, NOx and soot emissions decreased, and HC and CO emissions increased, while the peak in-cylinder pressure was slightly influenced. The results of this study indicate that the selection of the butanol-diesel blend ratio and injection timing should consider the engineering balances among the engine’s fuel economy and emissions.

Abstract: To solve the problem of testing BMBS (BLOW-OUT MONITORING AND BRAKE SYSTEM) vacuum booster performance, a double-station and on-line test system for BMBS vacuum booster was designed. It adopts high-speed data collection method and computer control technology. This system can test the performance in non-BMBS condition and BMBS condition. The test items mainly include dynamic characteristic and sealing performance under each condition. The double stations are independent and have no interference with each other. The system fills up the blank of performance testing about BMBS vacuum booster. To verify this system, experiments were conducted with the vacuum booster which installed the BMBS technology. The experiment results show that the system can do well in testing the performance of BMBS vacuum booster in high precision. The sealing performance resolution is 0.01kPa and the pressure resolution is 1N.

Abstract: An experiment for Marangoni condensation of ethanol-water mixtures was carried out and the departing radius and drop size distribution on vertical surface was presented. An amended formula was obtained after considering the effect of ethanol mass concentration, vapor velocity and condensing temperature difference based on Le Fevre’s formula concerning departing radius of pure water, The calculations were in good agreement with experimental result, had a maximum error less than 23%. Owing to the significant effect on drop size contribution, vapor velocity was introduced into Rose’s formula, and the correctional result compared well with the experimental data.

Abstract: With heavy mass and free falling body movement, the hammer is very dangerous and unstable during testing, so testing machine by the component systems of the research, designing a security system,including the mechanical structure of the safety design and safety of electrical control system design. In particular, the safety raising and releasing mechanism is designed to enhance the use of friction to achieve self-locking latch device functionality, so pin lock to prevent accidental operation errors will pull out, hammer will not be down. During the experiment, system have a good protection.

Abstract: Particular requirements to the Accelerator’s mechanical characteristic were put forward firstly. According these requirements, the Internal Parallel Moving Gears (IPMG) was proposed to be served as the accelerator used in the Electro-Magnetic Suspension(EMS). And its parameters of the EMS were calculated and optimized for the general layout of a special vehicle. Then in terms of the design results, the accelerator was trial-produced and tested. The experiment results indicated that the IPMG could realized big drive ratio in small volume really, but there was so difficult in machining, assembling, disassembling as in maintenance. In addition, because of its structure, it was not fit to transfer big force or high power but fit to transfer motion with middle or small power. Therefore, it was not suitable to act as a accelerator used in the EMS

Abstract: Early fault features of rotating machinery is very weak and is disturbed by strong noise generally. how to more accurately extract early (weak) fault features from signals is still a hot and difficult point of research of the discipline. An intensive study is given to basic features of rotating machinery early faults and common diagnosis method, And also summarized the research status of early diagnosis in the field of mechanical equipment signal feature extraction and fault diagnosis, analyzed the current problems, and finally briefly pointed out the development of early fault diagnosis in machinery applications.

Abstract: In here, a robust optimization mathematical model of the spring is presented. To minimize the error and maximal variations of spring stiffness coefficient related with structure parameters and its tolerances is chosen as its objective function, and the acceptable region is formed by some constraints. The theory is applied to the structure design of the closeing spring of spring actuator, the closeing characteristics are all satisfied at the optimum structure parameters, and the optimization results are discussed.