Advanced Materials Research Vols. 588-589

Abstract: Improving design of some automotive muffler is introduced, according to the existing problem of original exhaust muffler in is modified, using sound software attenuation characteristic is analyzed, and pressure distribution of muffler inner is performed to calculate adopting three-dimension flow field tool, and the muffler is tested on engine bench. Result shows that Compared with the original muffler, power loss is decreased by about 30%, set-net noise of the original muffler all has dropped dramatically, and it is in the target.

Abstract: As there are many shortcomings for the traditional three-way catalyst (TWC),too large thermal inertia ,low heat capacity and poor thermal insulation properties .A new hybrid vehicles special two-stage TWC is designed.The experiment was carried out at drum test bench and frequent start/stop cycle condition.The result shows that the first-stage catalyst core temperature was maintained at 450°Cafter engine stop 200s, the peak value of HC emissions is only exist at the beginning 30 sec and the conversion efficiency of NOx up to 90% .The hybrid vehicles special two-stage TWC fully meet the frequent start / stop and transient cycle conditions requirment.

Abstract: In oil-delivery pumps, impeller failure is a common cause leading to excessive vibration. This paper is aimed to analyze the fault causation of impeller failure in oil-delivery pumps by using fuzzy Petri net (FPN) theory. The longest path algorithm based on the forward reasoning was put forward and introduced into fuzzy Petri net. First, on the basis of various factors causing impeller failure, an FPN model of impeller failure in oil-delivery pumps was constructed. Then, by using the proposed algorithm, fault causation analysis of impeller failure was completed to calculate the credibility of impeller failure. Finally, the corresponding preventive measure was presented. The results indicate the key causing factor of impeller failure is mechanical impurities, and the credibility of impeller failure is 0.7342, which is consistent with the actual situation. The research finding demonstrates the flexibility and effectiveness of the FPN in fault causation analysis.

Abstract: In order to achieve a good idle speed stability, emission and economic effect for spark ignition engine, the air-fuel ratio has to been controlled under idle conditions. In this paper, an engine model for a 125cc EFI motorcycle engine was established using the GT-power software, and a simulation and experimental study was performed when engine under idle speed condition. The result shows that there is a corresponding relationship between the idle speed and the air fuel ratio. An accurate control method for setting optimal working air-fuel ratio under idle speed condition can be obtained using the results of this study.

Abstract: Based on the analysis of its motion performance about Hooke’s joint-gear mechanism, the Hooke’s joint-gear mechanism of differential velocity vane pump is brought forward. By analyzing its motion rule on the driving system of the differential velocity vane pump, the design parameters of the Hooke’s joint-gear mechanism of differential velocity vane pump are shown. The overall structure and its principle prototype are designed. Based on the principle prototype of the differential velocity vane pump, the experimental platform is established to testify the draining and trapping fluid. The results are shown that Hooke’s joint-gear mechanism of differential velocity vane pump can achieve the function of draining and aspirating fluid, and the design on the driving system and the pump structure are correct.

Abstract: Submarine noises, which mainly come from the propeller are the biggest threat to its survival, while the noises resulting from the propeller depend mainly on its 3d symmetry, the accuracy and roughness of its surface fine processing. In order to improve the accuracy and roughness of the fine processing, the detailed detection and amendment become quite difficult and also essential to the production of it. An optical detection and amendment method is put forward in this paper. The detection accuracy of this method can achieve the level of Nm, which is beyond the current production and detection standards at home and abroad.

Abstract: A numerical study is conducted in a port fuel-injection, spark-ignition engine fuelled with 1-butanol at different fuel/air equivalence ratios and inlet air temperatures. The effect of fuel/air equivalence ratio and inlet air temperature on the engine performance and emission characteristics is analyzed. The modeling results show that the incylinder pressure and temperature increases with the increase of fuel/air equivalence ratio. The slightly lean mixtures offer the maximum level of NOX emissions. In addition, preheating the inlet air can increase the incylinder pressure peak value and NOX emissions.

Abstract: The electronic throttle promotes the development of electronically controlled vehicle systems. The emergence of electronic throttle technology is in the United States in the 1980s.After that it is developed in Europe and Japan. As the technology advances and the cost reductions, the electronic throttle has been widely used in modern cars. China's electronic throttle technology comes from the introduction of technology, the core technology, however, still do not grasp. With the continuous progress of the domestic automobile manufacturers and domestic universities, electronic throttle has been applied in various models. In hybrid vehicles, the continuously variable transmission vehicles, the natural gas engines, diesel engines, and motorcycles，the electronic throttle is applied in research and obtain the corresponding scientific research. In the future of the car electric system, the electronic throttle will play an increasingly critical role and obtain the wide range of applications.

Abstract: The full power hydraulic brake system has several advantages over traditional brake actuation systems. These systems are capable of supplying fluid to a range of very small and large volume service brakes with actuation that is faster than air/hydraulic brake systems. Implementation of full power hydraulic brake system in off-road vehicles calls for good understanding of its dynamic characteristics. In this paper, we consider the problem of dynamic modeling of the brake system and develop a dynamic model for a hydraulic brake valve. First, the dynamic characteristics of full power hydraulic brake system are analyzed theoretically. The effects of varying design parameters (brake valve, accumulator and so on) and the different operating conditions are then analyzed. Second, we investigate the dynamic characteristics of a full power hydraulic brake system using a test bench, which is a loader brake system specifically designed for one construction Machinery Company. Finally, based on the experimental results, the mathematical models are amended and verified. The result shows that the model-calculated data agree well with tested data. The dynamic behavior of hydraulic valve can be well predicted with the model. The simplified models can be applied to the studies of full power hydraulic brake system dynamics.

Abstract: The development and engineering applications of beam-string-structure are introduced and a new space beam-string-structure with outer truss torus is proposed. The new structural system is to reduce the space occupied by roof structure and could be laid by the rigid roofing material easily. Three types of annular tensile cable-truss structure were given. Sunflower-patterned space beam-string-structure was taken as an example and its static behavior under full-span load and half-span load was analyzed. The efect of prestress level on static behavior of the structure was studied. The results will provide a reference for a further design and project application of such structure.