Failure Process and Mechanism Analysis for the Connecting Rod of Diesel Engine

2012 ◽  
Vol 463-464 ◽  
pp. 1597-1600
Author(s):  
Ying Kui Gu ◽  
Kang Hu ◽  
Jing Li
Keyword(s):  
Diesel Engine ◽  
Material Properties ◽  
Treatment Process ◽  
Failure Process ◽  
Organization Structure ◽  
Scientific Basis ◽  
Mechanism Analysis ◽  
Connecting Rod ◽  
Fault Mechanism ◽  
Physical And Chemical

The operational fault of diesel engine caused by losing the required function in running is a random phenomenon. It needs to collect a large number of fault samples and reliability data to reveal the fault occurrence rule and describe it with mathematical method. In this paper, the fault law and mechanism of the engine connecting rod were researched by the physical and chemical analysis of the fault samples. The fault reasons and the fault mechanism can be found through the analysis of the organization structure, material properties, process features, heat treatment process and other reliability information of the fault sample. It can provide scientific basis for the failure exclusion as well as the optimization and improvement of connecting rod structure.

scholarly journals Determination of Combustion Process Model Parameters in Diesel Engine with Variable Compression Ratio

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Saša Milojević ◽  
Radivoje Pešić
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Process Model ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Model Parameters ◽  
Connecting Rod ◽  
Variable Compression Ratio ◽  
Variable Compression

Compression ratio has very important influence on fuel economy, emission, and other performances of internal combustion engines. Application of variable compression ratio in diesel engines has a number of benefits, such as limiting maximal in cylinder pressure and extended field of the optimal operating regime to the prime requirements: consumption, power, emission, noise, and multifuel capability. The manuscript presents also the patented mechanism for automatic change engine compression ratio with two-piece connecting rod. Beside experimental research, modeling of combustion process of diesel engine with direct injection has been performed. The basic problem, selection of the parameters in double Vibe function used for modeling the diesel engine combustion process, also performed for different compression ratio values. The optimal compression ratio value was defined regarding minimal fuel consumption and exhaust emission. For this purpose the test bench in the Laboratory for Engines of the Faculty of Engineering, University of Kragujevac, is brought into operation.

Investigations on performance of diesel engine by varying injection timings with design modification on piston crown

2018 ◽  
Vol 15 (5) ◽  
pp. 562-566
Author(s):  
Vijaya K. ◽  
Shailesh Palaparty ◽  
Raghavan Srinivasa ◽  
Ravi Kumar Puli
Keyword(s):  
Diesel Engine ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Injection Timing ◽  
Connecting Rod ◽  
Design Modification ◽  
Content Type ◽  
Piston Head ◽  
Piston Crown ◽  
Fuel Vaporization

Purpose Investigations are carried out with the aim of improving performance of a diesel engine with the design modification on piston crown to stimulate the uniform combustion by inducing turbulence in the incoming charge. Design/methodology/approach A stirrer is introduced at the top of the piston so as to inculcate more turbulence to the incoming charge by improving the rate of fuel vaporization. Whirling motion is created in the combustible mixture by providing rotating blades on the cavity/bowl of the reciprocating piston head. By putting a simple link mechanism, the oscillatory motion of connecting rod will rotate the blade by an angle of 60°. Findings The investigations are carried out with and without swirl piston at 17.5 compression ratio and 200 bar injection pressure by varying injection timings. Originality/value Finally, the result shows that by using the modified piston, nearly 3 per cent of efficiency increased and 31 per cent of NOx emissions are reduced compared to that of a normal piston with 80 per cent load at standard injection timing.

scholarly journals Fractographic Study of Marine Diesel Engine Connecting Rod Stud Bolt Crack

2021 ◽  
Vol 58 (4) ◽  
pp. 28-42
Author(s):  
K. Carjova ◽  
V. Priednieks ◽  
R. Klaucans ◽  
I. Irbe ◽  
A. Urbahs
Keyword(s):  
Fatigue Crack ◽  
Diesel Engine ◽  
Tensile Tests ◽  
Marine Diesel Engine ◽  
Connecting Rod ◽  
Worst Case ◽  
The People ◽  
Marine Diesel ◽  
Fatigue Rupture ◽  
Fatigue Crack Development

Abstract Failures of marine diesel engine components can lead to serious consequences for a vessel, cargo and the people on board a ship. These consequences can be financial losses, delay in delivery time or a threat to safety of the people on board. This is why it is necessary to learn about connecting rod bolt failures in order to prevent worst-case scenarios. This paper aims at determining the origin, velocity and the duration of fatigue crack development of a diesel alternator engine which suffered a significant failure of one of its mains, not long after a major overhaul had been completed and with less than 1000 running hours having elapsed. It was verified with fatigue rupture of one of the four connecting rod stud bolts. Tensile tests were performed in the remaining connecting rod bolts. During this procedure, another fatigue crack in an adjacent bolt was identified. The probable root case of damage, and at the end some final remarks are presented.

scholarly journals Study on the influence of alumina nanomethanol fluid on the performance, combustion and emission of DMDF diesel engine

2021 ◽  
Vol 268 ◽  
pp. 01004
Author(s):  
Zenghui Yin ◽  
Jing Hao ◽  
Jiangjun Wei
Keyword(s):  
Diesel Engine ◽  
Nox Reduction ◽  
Chemical Properties ◽  
Reduction Ratio ◽  
Fuel Consumption Rate ◽  
Combustion Duration ◽  
Combined Use ◽  
Important Research Topic ◽  
Nanofluid Fuel ◽  
Physical And Chemical

With the increasingly strict domestic emission regulations, how to reduce diesel emission without affecting its output power has become a hot and important research topic. Due to their unique physical and chemical properties, the combined use of methanol and Al2O3 nanoparticles plays a unique role in promoting combustion and reducing emissions. In this study, Al2O3 methanol nanofluid fuel was injected into the inlet and diesel fuel was injected into the cylinder to explore the influence of Al2O3 nanoparticles on the performance, combustion and emissions of diesel methanol dual fuel (DMDF) entered. The experienced results showed that with the addition of Al2O3 nanoparticles in methanol, the peak pressure and heat release rate in the cylinder of the diesel engine were improved, the combustion delay period and the combustion duration were shortened, the fuel consumption rate was reduced by up to 10.8%, and the braking thermal efficiency was increased by 12.11% at most. With the addition of Al2O3 nanoparticles, NOx, CO, HC and soot ratio emissions of the engine were reduced, among which the NOx reduction ratio was small, and the maximum reduction ratio of the last three was 28.82%, 83.33% and 29.27% respectively.

Experimental Study on Fault Caused by Partial Arc Steam Forces and Its Economic Solution

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Daren Yu ◽  
Yanfeng Duan ◽  
Jinfu Liu ◽  
Zhansheng Liu ◽  
Qinghua Hu
Keyword(s):  
Experimental Study ◽  
Temperature Rise ◽  
Mechanism Analysis ◽  
Steam Turbines ◽  
Practical Test ◽  
Full Load ◽  
Control Stage ◽  
Fault Mechanism ◽  
Fault Characteristic

It is noticed in a few steam turbines that there are a pad temperature rise of more than 10°C and a radial journal movement of more than 50 μm in the bearings adjacent to control stage when they operate under partial arc admission at 60–80% of their full load. It is found through fault mechanism analysis and experimental study that the fault is caused by partial arc steam forces acting on control stage. A fault characteristic is concluded to help identify this fault. Diagonal admission is therefore proposed as an economic solution for elimination of this fault and it is proved to be effective through practical test.

Effect of Swirl Ratio and Injection Pressure on Autoignition, Combustion and Emissions in a High Speed Direct Injection Diesel Engine Fuelled With Biodiesel (B-20)

2009 ◽  
Author(s):  
Vinay Nagaraju ◽  
Mufaddel Dahodwala ◽  
Kaushik Acharya ◽  
Walter Bryzik ◽  
Naeim A. Henein
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Injection System ◽  
Ignition Process ◽  
Swirl Ratio ◽  
Mixture Formation ◽  
Physical And Chemical

Biodiesel has different physical and chemical properties than ultra low sulfur diesel fuel (ULSD). The low volatility of biodiesel is expected to affect the physical processes, mainly fuel evaporation and combustible mixture formation. The higher cetane number of biodiesel is expected to affect the rates of the chemical reactions. The combination of these two fuel properties has an impact on the auto ignition process, subsequently combustion and engine out emissions. Applying different swirl ratios and injection pressures affect both the physical and chemical processes. The focus of this paper is to investigate the effect of varying the swirl ratio and injection pressure in a single-cylinder research diesel engine using a blend of biodiesel and ULSD fuel. The engine is a High Speed Direct Injection (HSDI) equipped with a common rail injection system, EGR system and a swirl control mechanism. The engine is operated under simulated turbocharged conditions with 3 bar Indicated Mean Effective Pressure (IMEP) at 1500 rpm, using 100% ULSD and a blend of 20% biodiesel and 80% ULSD fuel. The biodiesel is developed from soy bean oil. A detailed analysis of the apparent rate of heat release (ARHR) is made to determine the role of the biodiesel component of B-20 in the combustible mixture formation, autoignition process, premixed, mixing controlled and diffusion controlled combustion fractions. The results explain the factors that cause an increase or a drop in NOx emissions reported in the literature when using biodiesel.

Microscopic Study on Mechanical Properties of Different Microregions during In-Service Welding

2019 ◽  
Vol 944 ◽  
pp. 841-853
Author(s):  
Ling Qiao ◽  
Tao Han ◽  
Hong Tao Wang ◽  
Lai Hui Han ◽  
Shi Wei Gu
Keyword(s):  
High Temperature ◽  
Dynamic Properties ◽  
Failure Process ◽  
Physical Nature ◽  
Repair Process ◽  
Scientific Basis ◽  
Economic Benefits ◽  
Dynamics Simulation ◽  
Microscopic Mechanism ◽  
Burn Through

In-service welding has been gaining considerable attentions due to its significant economic benefits. At high temperature, several technical difficulties exist during repair process and burn-through has been one of the critical issues. To reveal the physical nature of burn-through, finite element simulation and molecular dynamics simulation are combined to investigate the micro dynamic properties of different micro regions in welded joint and the effect of crack on the microdynamic behavior in the process of material failure. The results indicate that burn-through is a failure process under the effect of tensile stress and high temperature. The performance near fusion line is the worst and a burn-through tends to occur at the regions behind maximum melting depth. The failure process of welded joints experience the initiation and development of micro defects. Continuous expansion of micro holes and micro cracks causes the structural fracture. Furthermore, the micro crack would decrease the structural strength and the failure mode differs for cracks in different direction. Failure process of crack structure has experienced the crack tip passivation and dislocation emission. And the formation of stacking fault is carried out in failure process. This paper reveals the microscopic mechanism of burn-through at the atomic level and provides a scientific basis for the continuous and safe operation of gas pipelines.

scholarly journals Effects of sodium roasting on the leaching rate of boron-bearing tailings and its mechanism analysis

2018 ◽  
Vol 5 (8) ◽  
pp. 172342
Author(s):  
Chengxi Zou ◽  
Zhenyu Tang ◽  
Wei Xie ◽  
Hanguang Fu ◽  
Jiacai Kuang ◽  
...  
Keyword(s):  
Scientific Basis ◽  
Raw Material ◽  
Sodium Borate ◽  
Mechanism Analysis ◽  
Leaching Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Theoretical Amount

The study reported was intended to improve the leaching rate of boron-bearing tailings, using a method of sodium roasting that uses boron-bearing tailings as the raw material and Na 2 CO 3 as the sodium agent. The effects of the roasting temperature and Na 2 CO 3 amount on the leaching rate of boron-bearing tailings are mainly evaluated. The morphology and composition of the samples after sodium roasting are analysed by scanning electron microscopy and X-ray diffraction. The results show that sodium roasting can significantly improve the leaching rate of boron-bearing tailings. Under the optimal conditions where roasting temperature is 950°C, Na 2 CO 3 amount is five times the theoretical amount and roasting time is 2 h, the leaching rate of boron-bearing tailings is up to 86.78%. Based on the analysis of the characterization results and the mechanism analysis of the sodium roasting process, the main reason for the increase of leaching rate is the reaction between Na 2 O produced by the decomposition of Na 2 CO 3 and the boron in boron-bearing tailings resulting in soluble sodium borate. The results provide a scientific basis for the efficient comprehensive use of boron-bearing tailings.

scholarly journals Modelling of Time-Dependent Wellbore Collapse in Hard Brittle Shale Formation under Underbalanced Drilling Condition

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Shanpo Jia ◽  
Zhiqiang Xiao ◽  
Bisheng Wu ◽  
Caoxuan Wen ◽  
Lufeng Jia
Keyword(s):  
Immersion Time ◽  
Progressive Failure ◽  
Drilling Fluid ◽  
Progressive Collapse ◽  
Failure Process ◽  
Chemical Properties ◽  
Whole Process ◽  
Drilling Condition ◽  
Shale Formation ◽  
Physical And Chemical

In recent years, the lithologic traps in a mid-depth formation are the focus of oil or gas exploration and development for eastern oilfields in China. The Shahejie Formation develops thick hard brittle shale, and the wellbore instability problem is prominent due to obvious hydration effect for long immersion time during drilling. Through the analysis of laboratory tests and field test results of physical and chemical properties and microstructure and mechanical properties of hard brittle shale, the instability mechanism is discussed for the wellbore in the shale formation. To simulate the whole process of progressive collapse of a wellbore in a hard brittle shale formation, a coupled hydraulic-mechanical-chemical (HMC) model is developed and this model is compiled with ABAQUS software as the solver. Then the coupled HMC model is applied to simulate the progressive evolution process of wellbore collapse in a hard brittle shale formation, and the influence of different parameters on the progressive failure of the wellbore is analysed. The results show that the wellbore enlargement rate increases with the drilling fluid immersion time and the influence of different parameters on the wellbore enlargement rate is different. The water absorption diffusion coefficient and the activity of the drilling fluid have the most obvious influence on the expansion of the wellbore, and the sensitivity is strong. The permeability of shale has little effect on the wellbore enlargement rate. The calculated progressive failure process of the wellbore is basically consistent with that of the actual drilling.

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