Pin Hole Of Piston Research Articles

PROFILING THE SURFACE OF THE PIN HOLE IN THE PISTON BODY

Minimization of the mass of the piston kit, which consists of three main parts - piston, pin and connecting rod, is connected, among other things, with the possibility of reducing the diameter of the steel pin. On the other hand, a decrease in its diameter inevitably leads to an increase in stresses in the piston pin hole (PPH) and possible destruction. It is known that reducing the mass of the piston set from 5 to 20% leads to an increase in the output parameters of the internal combustion engine - torque and power by 1% to 4.5%. The purpose of the study is to determine the possibility of reducing the stresses in the bearing due to the profiling of its surface while reducing the diameter of the piston pin. The research algorithm is presented, which consists of building a geometric model of the piston assembly, loading with excessive pressure taking into account the plasticity of the material, modifying the geometry of the PPH and checking the stresses of the loaded state. The conventional piston model has the following geometry: diameter – 80 mm; height – 60 mm; compression height – 30 mm; the diameter of the finger hole is 18 mm; the distance between the bumps is 28 mm. Piston material – aluminum-based alloy – AISI 2014-0, pin and connecting rod material – AISI 1020 steel. Pressure loading conditions: taking into account plasticity – nonlinear, harmonic, 2 cycles, maximum amplitude – 8 MPa; test - static, 6.5 MPa. A crumpling zone with residual deformations was detected in the PPH, the maximum final deformation practically does not differ in the first and second load cycles (0.0081 vs. 0.0084). Residual deformations occur 1/3 of the length from the inner edge of the head. The absolute residual deformations are given in the form of a sweep of the change in the PPH radius. The maximum value is about 0.04 mm. This result is the basis for modifying the geometry of the surface of the finger hole. The modified geometry of the PPH is obtained by boring the cylindrical surface with a profile modeled by the appropriate spline on the geometric model. The boring axis is offset by 0.02 mm from the PPH axis. Verification modeling showed that the averaged loads on the edge of the model are 143 MPa for the cylindrical and 107 MPa for the modified PPH (-25% for the modified profile).

Failure analysis and pin hole profile optimization design of combined piston for marine diesel engine based on Kriging model and NSGA-Ⅱ algorithm

Amidst the drive for enhanced performance and reliability in marine diesel engines, anti-fatigue design has emerged as a pivotal factor in ensuring safe operation. To investigate the cracking of a steel-topped aluminum-skirted combined piston in a marine diesel engine, thorough analyses were conducted on mechanical properties, chemical composition, and microscopic morphology. Subsequently, a piston thermo-mechanical coupling (TMC) model was established to simulate stress distribution and fatigue strength. Findings revealed that loose defects in the material and deformation mismatch in the pin hole bearing TMC were the primary factors contributing to cracking. Based on this, a multi-objective optimization (MOO) design method for piston pin hole profiles was proposed. Optimal pin hole profile design parameters were determined using the Kriging surrogate model and the second generation non-dominated sorting genetic algorithm (NSGA-II), and the nonlinear relationship between the design variables and the response objectives was obtained. Post-optimization, stress in the piston cracking source region decreased by 40.6%, peak contact pressure and stress in the pin hole decreased by 59.2% and 49.1%, respectively. Furthermore, the minimum fatigue safety coefficient improved from 0.86 to 1.18.

Piston structure design and finite element analysis

The working characteristics of internal combustion engines rely on the explosive combustion of fuel in the combustion chamber to drive the piston movement. This working characteristic causes the main component of the combustion chamber, the piston, to bear high thermal and mechanical loads. It has very high requirements for design, manufacturing, and material selection. The working condition of the piston will affect its safety and stability. Therefore, the finite element analysis for the piston is particularly important. Thus, this article first establishes the piston model and divides it into grids in ANSYS, adds boundary conditions, and conducts analysis. The piston thermal analysis mainly includes thermal stress and deformation analysis under thermal load. The piston’s maximal thermal stress is 170.23 MPa and the deformation of thermal expansion is 0.61585 mm. The mechanical stress and deformation analysis under mechanical load are carried out. The maximal stress is 164.91 MPa and the maximal deformation caused by the mechanical stress is 0.24916 mm. Finally, the coupling analysis of thermal and mechanical stress is conducted. The maximal stress is 251.74 MPa, which is located at the outskirt margin of the piston pinhole. The maximal deformation is 0.60779 mm. The simulation analysis results indicate that the method proposed in this article provides a way to design the structure of similar automotive components such as pistons.

Preparation and mechanical properties of LC cladding layer for friction parts

Introduction: In the actual engineering operation, there are some components facing high frequency friction, which have high damage rate and poor direct replacement benefit. In order to achieve sustainable resource utilization and more effective component remanufacturing, research was conducted on the cladding layer of friction components.Methods: Based on the idea of remanufacturing, taking 42CrMo as the raw material of engine piston pin hole, laser cladding technology and ultrasonic rolling technology are used to prepare the cladding layers of Fe, Ni and Co three different substrates.Results and Discussion: The experimental results showed that the Co based cladding layer with ultrasonic rolling technology performed best. The surface roughness reduced by 1.02 μm, only 0.14 μm. The microhardness increased by 101.39%, with 795.38 HV. The friction coefficient was 0.051. The friction rate at high temperature decreased by 85.71%, and it was 1.2%. The friction at high temperature was reduced by 79.24%, with 0.9%.Conclusion: Co based cladding layer combined with ultrasonic rolling technology shows the best performance, which can effectively realize the remanufacturing of engine piston pin hole, providing technical reference and data support for the remanufacturing process of high-frequency friction components.

A new method to establish coupled multi-physics model of lubricated pin-hole oscillating pair

Under severe working conditions, about 10 % of the total engine friction loss originates from the piston pin-hole oscillating pair, significantly impacting the engine's reliability. Nevertheless, a systematic analysis encompassing the multi-physics environment (including lubrication, dynamics, and heat transfer) and their coupled behaviors is still lacking. A new coupled modeling method is proposed to achieve this, which can account for thermal deformation and frictional heat generation. All key components in this study are represented as three-dimensional flexible bodies, enabling a thorough characterization of the intricate secondary motions influencing lubrication. The method is applied to a lubricated oscillating pair test system, and a 1:1 simulation model is established. Experimental results also affirm its high accuracy. The model calculation results demonstrate that thermal deformation constrains pin secondary motions and increases axial load inhomogeneity. After factoring in fluid and asperity friction heat, the average friction coefficients at the small end hole (SEH) and pin base hole (PBH) increase by 1.8 % and 11.3 %, respectively. Furthermore, a parametric analysis is conducted, and the instantaneous friction coefficient curves under different loads/temperatures/frequencies are given. These findings can offer valuable insights into the tribological design of oscillating pairs.

Thermo-mechanical coupling strength analysis of a diesel engine piston based on finite element method

ABSTRACT Due to improvements in diesel engine power and performance, the piston in the combustion chamber is subjected increasingly higher thermal and mechanical loads. The cyclic changes in thermal and mechanical stresses seriously affect the piston fatigue life. Therefore, it is necessary to analyze the strength of the piston in the design process. In this paper, the finite element analysis of piston under thermal, mechanical and thermo-mechanical loads coupling is carried out by using the ANSYS software. By analyzing the heat and force distributions on the piston, the stress and strain distributions on the piston can be obtained, so as to determine the maximum stress concentration areas and check whether the piston strength meets the requirements. Results indicate that the highest temperature on the piston appears at the top of the combustion chamber bulge, where the deformations of the piston and combustion chamber are the most serious. There is a large stress concentration in the contact between the piston pin seat, the piston pin hole and the piston. The minimum number of piston cycles is 1.2×106 times, which meets the piston cycle number from starting, running, and to stopping process. Thus the strength of the diesel engine piston meets the requirements.

Research on Multi-Parametric Coupling Design Method of Deformable Boring Bar in Embedded Giant Magnetostrictive Actuator

Deformable boring bar is the executive component of embedded giant magnetostrictive actuator (GMA), which plays a key role in the output performance of embedded GMA in precision machining of non-cylindrical piston pinhole. In this paper, a multi-parametric coupling design method was presented for deformable boring bar and giant magnetostrictive material. Firstly, the dynamic model of deformable boring bar was built. Second, the performance index of length-diameter ratio was introduced, and the problem of multi-parametric coupling design was solved by using the idea of nonlinear programming. The first-order natural frequency, the end output displacement and the output force of deformable boring bar were taken as the evaluation indexes to ensure the performance requirements of embedded GMA. Finally, according to project requirements and proposed method, an embedded GMA with high frequency response and large output displacement was further designed, which met the performance requirements of displacement and stiffness in precision machining of non-cylindrical piston pinholes and also verified the validity of the design method.

Simulations of engine knock flow field and wave-induced fatigue of a downsized gasoline engine

A mathematical correlation is developed, based on the thermodynamic model of a downsized gasoline engine, to establish the numerical relationship among the thermodynamic parameters of the combustion chamber. In the developed numerical model, the in-cylinder pressure curves of various operation conditions are simulated by varying the air–fuel ratio in the cylinder, and the associated knock characteristics are recorded. The accuracy of the numerical simulation results is verified against the knock excitation experiment. Then, based on the Rover K16 gasoline engine, a simulation model is developed to simulate the engine knock in the combustion chamber and observe the force acting on the top surface of the piston. The results show that the forces, which act on the piston top surface, are varying at various locations at the same time, and the largest forces occur at the edge of the piston and followed by the piston centre. Then, by comparing the thermo-mechanical coupling strength of the piston under different operating conditions, the results show that the occurrence of the knocking does not exceed the piston’s strength limit. However, the stress and deformation value of the piston is increased significantly, and the failure point of the piston position is changed. Finally, based on the calibrated strength results, the piston durability is predicted for various engine knock conditions. The results show that there is an initial damage of piston in the process of detonation at the surface of the piston pin hole and the joint of the piston cavity. The gasoline engine finally has a predicted mileage of 2,53,440 km continuously, which meet the prescribed mileage of 2,20,000 km.

Influence of piston pin hole offset on cavity erosion of diesel engine cylinder liner

In order to reduce the striking and lateral force between piston and wet cylinder liner of diesel engines as well as to curb the cavitation of the cylinder liner, the influence of the piston pin hole offset on cavitation was systematically investigated. The bench test was carried out by employing the six cylinder inline diesel engine with different offset of piston pin hole, then the surface and section of the cylinder liner were measured and observed. In addition, the kinetic energy of piston as well as the vibration acceleration of cylinder liner under different offset of piston pin hole were calculated by dynamic numerical simulation comparing with the corresponding characteristics of the secondary motion. The results showed that after 500 h of running under standard conditions, obvious cavities were found on the cylinder liner without any offset of piston which expanded rapidly. By contrast, a good surface condition was found in the scheme with an negative offset. Meanwhile, the kinetic energy of piston reduced monotonously when the offset of the pin hole increased from 0 to −1.2 mm. Precisely, the maximum of kinetic energy corresponding to −0.5 mm and −0.8 mm offsets decreased by 41% and 59% respectively. Although it was even lower at −1.2 mm, the corresponding friction loss rose significantly which was detrimental to the stable operation between piston and cylinder liner. In addition, the vibration acceleration of cylinder liner in each scheme also decreased monotonically with the increase of the absolute value of the negative offset of the piston pin hole with a faint amplitude of fluctuation. Therefore, an appropriate negative offset of the pin hole could effectively improve the impact of the secondary motion of piston on the cylinder liner so as to effectively impede the cavitation which lays the foundation for enhancing the stability of the engine.

Design and Implementation of Measurement Instrument for Non-Cylinder Pinhole of Piston

For simplifying the cockamamie measurement process, in this paper, special equipment for measuring non-cylinder pinhole of piston is designed and implemented. First of all, the measuring principle, the hardware structure and the software system are illustrated. In addition, the measurement error is analyzed in detail. Finally, it is proved that the precision of the instrument is as high as that of the foreign advanced instrument.

Multi-Physics Coupling Field Nonlinear Finite Element Model for Giant Magnetostrictive Smart Component

This paper presents three dimensional nonlinear finite element modeling of giant magnetostrictive materials. The nonlinear relationship between magnetostrictive strain and magnetic field is described by experimental curve. Model is implemented using finite element software CMOSOL multiphysics 3.2a. A new method for precise machining non-cylinder pin hole of piston by using embedded giant magnetostrictive smart component is presented. The effects on smart component deformation and the system resonance frequencies are studied. This model is verified against experimental results, with a good agreement.

Study on the Characteristics of Loosely Coupled Transformer in Inductive Power Transfer System

A new kind of non-contact loosely coupled transformer of transmission method was proposed based on the principle of electromagnetic, thus to solve the problems of signal transmission in boring machine processing non-cylinder piston pin hole system. In this study, the factors that influence loosely coupled transformer characteristics are discussed, including coil position and air gap. Then, their influences are detailed presented by means of ANSYS simulation. Furthermore, choose appropriate coil position structure and air gap provides the reliable theory basis for non-contact power transfer system transmission.

Measurement System for Non-Cylinder Pin Hole of Piston

Aim to the low measuring precision of non-cylinder pin hole using the coordinate measuring machine(CMM)and pneumatic measuring instrument, a new solution is proposed which use the high-precision digital lever probe to detect the contours of pin hole with a single clamping situation. The measuring principal of non-cylinder pin hole of piston is introduced and the functions and measuring processes of the measurement system are also presented. The software modules are given and the probe centering error and the parallelism movement error are discussed detailedly. A measuring example is given in the end. The measuring results show that the measurement system has the ability to detect the contours of pin hole with high-precision and efficiently.

Analysis and Optimization on the Gating System of Aluminum Alloy Piston in Casting

Shrinkage porosity defects occurring in ring groove underside the pin hole of aluminum piston are strongly influenced by the time-varying temperature profiles inside the solidifying casting. By adopting the finite element analysis software PROCAST and combining with production practice, the gating system which has open-cycle ring feeding channel in the bottom of the piston was compared with conventional techniques; the influence of opening angle of ring feeding channel and different process parameters on shrinkage distribution was researched. The results show the gating system with open-cycle ring feeding channel can satisfy progressive solidification and effectively eliminate the shrinkage in ring groove underside piston pin hole, and can greatly reduce the riser size and improve casting yield; the opening angle influences shrinkage distribution and can be adjusted to achieve effective feeding; shrinkage size is influenced by pouring temperature and casting speed which have less effect on shrinkage distribution. The system of ring feeding channel is adopted, the opening angle and process parameters are adjusted, all which can effectively eliminate shrinkage in the bottom of the piston, improve casting yield and process rate.

Novel mechanism for boring non-cylinder piston pinhole based on giant magnetostrictive materials

To bear more loads for heavy truck pistons, the shape of heavy truck piston pinhole is often designed as non-cylinder form. Current methods cannot meet the needs for precision machining on non-cylinder piston pinhole (NCPPH). A novel mechanism based on giant magnetostrictive materials (GMM) is presented. New models are established for the servo mechanism, GMM, and magnetizing force of the control solenoid to characterize the relationship between the control current of the solenoid and the displacement of the giant magnetostrictive actuator (GMA). Experiments show that the novel mechanism can meet the needs to perform fine machining on NCPPH effectively.

Research on control method for machining non-cylinder pin hole of piston

The control method for machining non-cylinder pin hole of piston was studied systematically. A new method was presented by embedding giant magnetostrictive material (GMM) into the tool bar proper position. The model is established to characterize the relation between control current of coil and deformation of tool rod. A series of tests on deformation of giant magnetostrictive tool bar were done and the results validated the feasibility of the principle. The methods of measuring magnetostrictive coefficient of rare earth GMM were analyzed. The measuring device with the bias field and prestress was designed. A series of experiments were done to test magnetostrictive coefficient. Experimental results supplied accurate characteristic parameter for designing application device of GMM. The constitution of the developed control system made up of displacement detection and temperature detection for thermal deformation compensation was also introduced. The developed machine tool for boring the non-cylinder pin hole of piston has the micron order accuracy. This control method can be applied to other areas for machining precision or complex parts.