Papers by Keyword: Piston

Abstract: The energy balance of Hydraulic Confined Piston Engine (HCPE) is the key to understanding its working mechanism, improving its efficiency. The working principle of HCPE was presented, and the energy balance for the rated condition and application characteristics for the full conditions were also studied. Taking the low thermal value of fuel into account, the percentage of energy loss related to combustion is 54.99%, the percentage related to friction is 5.59%, the hydraulic loss is 1.92% and the other losses are 1.10%; the efficient work is 36.40%. The efficient work and the loss related to combustion are similar to those of a hydraulic free piston engine and medial speed diesel engine.

Abstract: The paper analyzed the temperature field and the thermal stress field of a diesel engine piston with finite element analysis software ANASYS, then used the thermal mechanism indirect coupled method, researched the coupled stress field of piston. The result indicated that the point of the highest temperature located on the middle of firebox which under the dangerous temperature of the material; under thermal stress effect, the max displacement of the piston did not exceed the clearance between piston and cylinder liner, but the non-roundness at the third ring reached 0.08mm, which had some influence on the pressurize and lubricate of piston; under thermal mechanism coupled effect, the point of max stress located on the interface of the seat of the pin and the pin hole, so as the top on the pin hole and inner on the seat of pin, so it was recommended to set rib between cervix and the seat of pin of piston to enhance the practical carrying capacity of the seat of the pin.

Abstract: According to the structure features of the piston, the method of combining application of finite element simulation and theoretical analysis was explored to determine the extrusion process program and the extrusion process parameters. Theoretical calculation shows that a longitudinal extrusion and a lateral extrusion can form piston. The result comparing simulative prediction with theoretical calculation demonstrates that there is a good fit between the two and the theoretical calculation is right. The result of simulative prediction demonstrates that the grain size of piston after extrusion is about 17.8 μm and the refining rate reaches 55%. The grain size on both sides of the piston skirt and piston internal floor place is about 27 μm, so the refining effect is less obvious than other parts. However, the grain refinement in the piston pin holes is more obvious, the grain is refined to 13 μm and the refining rate is about 67.5%.The result comparing simulative prediction with the experimental analysis demonstrates that there is a good fit in grain refinement between the two.

Abstract: Besides the actual average pressure, the actual specific fuel consumption and the actual performance, the actual torque is one of the characteristic indicators considered when designing a spark-ignition engine. In order to determine the effective power, special and quite expensive benches are required. This paper intends to determine certain computational relations for the determination of the actual torque both for a standard engine and for a ceramic-coated engine. In order to obtain the experimental results, we used the spark-ignition engine 810-99, and the actual torque was determined on a specialized bench. All measurements were performed at 28°C air temperature, and 740mmHg atmospheric pressure, the temperature of the cooling liquid being 82÷91°C and the oil temperature 92÷116°C. For the engine with ceramic crown’s piston, was maintained the same compression ratio, and the atmospheric pressure and temperature conditions were close to those of the standard engine. Both for the standard engine and for the ceramic engine all measurements were performed under full load. After computer processing the experimental data, empirical formulas were determined for the computation of the effective power both for the ceramic engine and for the standard engine.

Abstract: This paper selects two kinds of different avoiding valve pits of piston as the processing object, establish manufacturing process and complete the simulation of NC machining to generate NC code for machining avoiding valve pits in the Mastercam software, try to machine avoiding valve pits with two kinds of surface programming method in the Mastercam software, discuss and analysis the effect in programming and NC machining of avoiding valve pits in two kinds of different surface finishing method , to choose an appropriate kind of processing method for avoiding valve pits of piston.

Abstract: The finite element modeling is based on the aluminum-silicon alloy piston compression performance test by using both 10-node tetrahedron element and 10-node hexahedron element. After analyzing four grid types, we found that employing both tetrahedron element and hexahedron element can obtain stress-strain nephogram, but with a difference between the four modeling results. In the context of having the same grid size, 10-node hexahedron element reflects a fairly accurate piston stress-strain status than the 10-node tetrahedron element, and among the four schemes, the result calculated by analyzing the locally refined grid that containing both 2mm and 1mm sized 10-node hexahedron grids is the one that matches the experimental value best.

Abstract: Twin-rotor piston engine (TRPE) is a new differential rotary engine, which is still under developing. In this paper, a rigid-flexible coupling dynamics model was established for the prototype TRPE-350. By combining the multi-body dynamics simulating software RecurDyn and the finite analysis software ANSYS, the TRPE′s performances were studied. Vibration analysis for rigid-flexible coupling model was analyzed. The simulation results can be found that the simulated overall changing trends match with the actual movement of the TRPE very well. So it provides a theoretical tool for further optimization and improvement of this engine.

Abstract: Analysis was carried out to the kinematics between piston and cylinder block in the axial piston motor. And the formula of displacement, velocity and acceleration of the movement of piston in the cylinder block were given, and some suggestions were also presented to help the design of the axial piston motor with high speed and high pressure in the further.

Abstract: To assess piston’s thermal loads, the direct and effective method is to calculate piston’s temperature distribution. A key point in calculating the temperature field of a piston is the determination of heat transfer boundary conditions of each side, especially the gas side. The thermal boundaries of a piston consist of the piston top side (combustion side), the crevice surfaces, the piston ring land and skirt outside surface, piston underside and pin hole side.The calculating methods for the heat transfer boundary conditions of engine piston are studied according to the theoretical analysis of heat transfer of engine piston, which can be taken as a reference for providing precise boundary conditions for the research on piston’s temperature field.

Abstract: This contribution is focused on the analyze the possibilities of increasing the power of two-stroke internal combustion engine and their consequential execution in the practice. Currently dealing with these issues major manufacturers of motorcycle international brands, but also service technicians of professional riders, as well as regular users of motorcycles. The basic objective of this paper is the issue of increasing power output for single-trace motor vehicles, and objective of the experiment was to increase performance through volumetric efficiency, i.e. increase indicated mean effective pressure. The results of the experiment were tested on the specific equipments and in practice. In conclusion paper presents the benefits and results of the experiment. By means of measurements on the performance brake, in the final stage of paper is tested by how much increased power output of the engine after modification, compared to the production engine.