Analisis Kerusakan Engine High Blow-By Pressure Pada Mesin SA6D125E-2 UNIT bulldozer D85ESS-2A

Bulldozer merupakan alat berat yang digunakan untuk mendorong material dan untuk pembukaan jalan. Dalam melakukan pekerjaannya, bulldozer banyak menggunakan tenaga mesin sehingga sering terjadi kerusakan pada komponen mesinnya. Kerusakan high blow-by pressure pada mesin bulldozer merupakan hal yang perlu diperhatikan karena dapat menyebabkan kerusakan pada komponen di dalam mesin dan mengakibatkan menurunnya performa mesin. Penelitian ini dilakukan dengan mengidentifikasi data pada technical analysis report, program analisis pelumas, dan hasil overhaul. Technical analysis report dilakukan dengan cara mengukur blow-by pressure dan engine speed untuk mengetahui performa engine. Program analisis pelumas dilakukan dengan mengambil sampel oli pelumas lalu dianalisis di laboratorium untuk mengetahui keausan dan kontaminan pada oli pelumas engine. Dari hasil penelitian, dapat ditarik kesimpulan bahwa penyebab dari kerusakan high blow-by pressure adalah masuknya kontaminan berupa debu kedalam ruang bakar dan menyebabkan gesekan abnormal pada piston, piston ring, dan cylinder liner. Gesekan abnormal ini mengakibatkan celah antara piston, piston ring, dan cylinder liner semakin besar sehingga tekanan hasil pembakaran bocor menuju crankcase melewati celah tersebut. Dampak yang ditimbulkan dari kerusakan high blow-by pressure adalah penurunan tenaga mesin, sehingga unit bulldozer harus dilakukan perbaikan dengan mengganti komponen yang rusak agar unit dapat bekerja dengan optimal.

Effect of Coating and Low Viscosity Oils on Piston Ring Friction under Mixed Regime of Lubrication through Analytical Modelling

This paper presents the impact of coating topography in piston ring-liner conjunction under mixed regime of lubrication using low viscosity oils. The study provides a time efficient analytical model including mixed-hydrodynamics regime of lubrication under different contact conditions. The method modified the expressions of the contact load and area of Greenwood-Tripp model in order to capture the real asperities interaction into contact. The model represents the tribological behavior of a thin top ring at Top Dead Centre, where boundary and mixed conditions are predominant. Electroplated CrN and PVD TiN coated rings were studied to predict the ring friction. The results are compared with an uncoated steel ring. The CrN coating shows slighter coefficient of friction, due to the coating morphology and roughness parameters. The TiN coating presents thicker lubricant films and higher coefficient of friction because the surface topography is quite rough with high peaks. This can be explained because of the major contribution of the roughness parameter and asperity slope in the boundary friction prediction.

Tribological evaluation of piston ring/cylinder liner assembly in automotive engines using GNP as a lubricant additive

Friction and wear are the main causes of energy dissipation in automotive engines. To minimize the frictional power losses, it is extremely important to improve the tribological characteristics of ring/liner assembly which accounts for almost 40–50% frictional power losses. The present study attempts to mitigate friction and wear of the ring/liner tribo-pair using GNP/SAE 15W40 nano-lubricant. To simulate the ring/liner interface, the tribological performance of nano-lubricants was assessed using a tribometer based on ASTMG181 standard under various operating conditions. The coefficient of friction (COF) and wear rate lowered using graphene nano-lubricants (GNL). The tribological results showed that friction coefficient, wear rate, and surface roughness of piston ring improved in the range 17.71%–42.33%, 25%–40.62%, and 61%, respectively, under GNL lubricating conditions during the boundary lubrication. Further, the characterization of wear tracks of piston ring and cylinder liner confirmed tribo-film formation on worn surfaces resulting in decreased COF and wear rate.

Study of the Kinematics and Dynamics of the Ring Pack of a Diesel Engine by Means of the Construction of CFD Model in Conjunction with Mathematical Models

The present research aims to analyze the kinematic and dynamic behavior of the piston ring package. The development of the research was carried out through the development of numerical simulation by means of CFD. The analysis involves the three piston rings for the development of simulations that are closer to the real conditions of the engine since most of the investigations tend to focus on the study of the compression ring only. The simulation was reinforced by the incorporation of mathematical models, which allow determining the piston kinematics, the lubrication properties as a function of temperature, contact friction, and gas leakage. For the simulation, the CAD of the piston and the connecting rod—crankshaft mechanism was carried out, taking as a reference the geometry of a diesel engine. From the results obtained, it was possible to show that the first ring exhibits considerably greater radial and axial movement compared to the second and third piston rings. Additionally, it was shown that the first and second rings tend to maintain a negative tilt angle throughout the combustion cycle, which facilitates the advancement of the combustion gases over the piston grooves. Therefore, it is necessary to use strategies so that these rings tend to maintain a positive inclination. The analysis of the pressure conditions in the second ring are 150% and 480% higher compared to the conditions present in the third ring. Due to the above, it is necessary to focus efforts on the design of the profile of this ring. The study of energy losses showed that the combination of leakage gases and friction are responsible for a mechanical loss between 6–16%. In general, the development of the proposed methodology is a novel tool for the joint analysis of the kinematic characteristics, pressure conditions, and energy losses. In this way, integrated analysis of changes caused by piston ring designs is possible.

Analysis of leakage characteristics for bent-axis piston pump based on elastohydrodynamic deformation

Purpose This paper aims to revel the leakage characteristics of the bent-axis piston pump considering elastohydrodynamic deformation via a dynamic leakage model. Design/methodology/approach A dynamic leakage model of bent-axis piston pump based on elastohydrodynamic lubrication theory is proposed, which is used to present the leakage characteristics of bent-axis piston pump. The model is composed of three parts. First, the dynamic gap in the piston ring-cylinder bore interface (PRCB) is described via the elastohydrodynamic lubrication equations. Then, the PRCB leakage is presented based on the dynamic gap. Finally, combined with leakage equation of the valve plate-cylinder block interface (VPCB), the total leakage model is proposed. Through the numerical simulation and experiment, the leakage characteristics of bent-axis piston pump considering elasto-hydrodynamic deformation are studied. Findings The PRCB leakage is negatively correlated with VPCB leakage under the range of 800–1400 r/min and 1–25 MPa. When the discharge pressure is less than the critical pressure, the PRCB leakage is the main factor affecting the total leakage in bent-axis piston pump. On the contrary, the VPCB leakage is the main factor. The critical pressure increases with increasing speed Originality/value The effect of operating parameters has a significant effect on the elastic deformation of piston ring without considering wear of friction pairs in bent-axis piston pump. There is a critical phenomenon in the leakage, which is related to the operating parameters, and provides a novel idea for extracting wear information from leakage and evaluating the status of bent-piston pump.