Cavitation in Engine Lubricants: Visualisation Experiments in both a Single Ring Test Rig and a Single Cylinder Motored Diesel Engine to Complement on the Theoretical Modeling of Cavitation

2019 ◽  
Vol 21 (9) ◽  
pp. 1597-1611 ◽  
Author(s):  
Polychronis Dellis

The laser-induced fluorescence technique is based on the excitation of molecules of a fluorescent material by a light source. The main advantage of this technique is that it has the potential to quantify the lubricant film thickness throughout the cycle. Similar to all the other optical techniques, it has this major advantage compared to the electrical techniques where the oil film can be measured only under the piston rings. In this work, experimental data from a simulating single-ring test rig are presented and further parametric analysis is given regarding cavitation in lubricants that was, at first, in the case of the single-ring test rig, evident in laser-induced fluorescence measurements. Different lubricants are used for the laser-induced fluorescence experiments and the different laser-induced fluorescence signals are analysed and interpreted compared to their physical and chemical properties and, furthermore, with the aid of imaging through a glass liner, a clearer picture is given regarding the cavitation shapes together with the respective laser-induced fluorescence measurements and cavitation initiation.


Author(s):  
Aravind Sivaraman ◽  
Sridhar Ranganathan ◽  
Shashank Tangirala ◽  
G. Lakshmi Narayana Rao

The objective of this work is to compare the quality of various diesel fuels using a normal engine and carrying out the test under the actual operating conditions of the engine, unlike the conventional test methods that uses standard test conditions. The standard test conditions involve the running of the diesel engine test rig at a speed of around 800 rpm, which is not the condition when the fuel is actually being used, as the operational speed of commercial engines is around 1500–2000 rpm. Also the non-engine based quality rating methods are not economically liable and are inaccurate as they depend too much on the chemical nature of the fuel. So, the objective of this work is to develop a generalized quality rating procedure with less number of parameters, with a simpler and cheaper method compared to other available methods. A single cylinder diesel engine was used to study the ignition quality of various reference fuels of known Cetane numbers. A relatively simple and compact setup was used, by modifying the existing test rig. The inlet manifold was incorporated with an airflow control valve so that the quantity of air let into the cylinder can be varied. The exhaust gas manifold was modified to enable easier observation of the exhaust gas. The single cylinder diesel engine was made to run at two distinct conditions, namely, the normal and white-puff / critical condition, with the reference fuels of known cetane numbers. The quantity of air available for the fuel to combust is the only difference between the two conditions. The air-fuel ratio of each fuel under both the conditions was continuously monitored. A correlation was developed between the critical air-fuel ratios and the corresponding Cetane numbers. From this correlation, a test fuel can be rated easily by finding the air-fuel ratio, by running it in the same engine at an identical load, at an instant when the “white puff” is observed.


Author(s):  
M. A. Adzmi ◽  
A. Abdullah ◽  
Z. Abdullah ◽  
A. G. Mrwan

Evaluation of combustion characteristic, engine performances and exhaust emissions of nanoparticles blended in palm oil methyl ester (POME) was conducted in this experiment using a single-cylinder diesel engine. Nanoparticles used was aluminium oxide (Al2O3) and silicon dioxide (SiO2) with a portion of 50 ppm and 100 ppm. SiO2 and Al2O3 were blended in POME and labelled as PS50, PS100 and PA50, PA100, respectively. The data results for PS and PA fuel were compared to POME test fuel. Single cylinder diesel engine YANMAR TF120M attached with DEWESoft data acquisition module (DAQ) model SIRIUSi-HS was used in this experiment. Various engine loads of zero, 7 N.m, 14 Nm, 21 N.m and 28 N.m at a constant engine speed of 1800 rpm were applied during engine testing. Results for each fuel were obtained by calculating the average three times repetition of engine testing. Findings show that the highest maximum pressure of nanoparticles fuel increase by 16.3% compared to POME test fuel. Other than that, the engine peak torque and engine power show a significant increase by 43% and 44%, respectively, recorded during the PS50 fuel test. Meanwhile, emissions of nanoparticles fuel show a large decrease by 10% of oxide of nitrogen (NOx), 6.3% reduction of carbon dioxide (CO2) and a slight decrease of 0.02% on carbon monoxide (CO). Addition of nanoparticles in biodiesel show positive improvements when used in diesel engines and further details were discussed.  


2021 ◽  
Vol 11 (15) ◽  
pp. 6749
Author(s):  
Zhifeng Xie ◽  
Ao Wang ◽  
Zhuoran Liu

The cooling system is an important subsystem of an internal combustion engine, which plays a vital role in the engine’s dynamical characteristic, the fuel economy, and emission output performance at each speed and load. This paper proposes an economical and precise model for an electric cooling system, including the modeling of engine heat rejection, water jacket temperature, and other parts of the cooling system. This model ensures that the engine operates precisely at the designated temperature and the total power consumption of the cooling system takes the minimum value at some power proportion of fan and pump. Speed maps for the cooling fan and pump at different speeds and loads of engine are predicted, which can be stored in the electronic control unit (ECU). This model was validated on a single-cylinder diesel engine, called the DK32. Furthermore, it was used to tune the temperature of the water jacket precisely. The results show that in the common use case, the electric cooling system can save the power of 255 W in contrast with the mechanical cooling system, which is about 1.9% of the engine’s power output. In addition, the validation results of the DK32 engine meet the non-road mobile machinery China-IV emission standards.


2021 ◽  
Vol 1068 (1) ◽  
pp. 012016
Author(s):  
Hazim Sharudin ◽  
N.A. Rahim ◽  
N.I. Ismail ◽  
Sharzali Che Mat ◽  
Nik Rosli Abdullah ◽  
...  

Author(s):  
Mustafa Babagiray ◽  
Hamit Solmaz ◽  
Duygu İpci ◽  
Fatih Aksoy

In this study, a dynamic model of a single-cylinder four-stroke diesel engine has been created, and the crankshaft speed fluctuations have been simulated and validated. The dynamic model of the engine consists of the motion equations of the piston, conrod, and crankshaft. Conrod motion was modeled by two translational and one angular motion equations, by considering the kinetic energy resulted from the mass moment of inertia and conrod mass. Motion equations involve in-cylinder gas pressure forces, hydrodynamic and dry friction, mass inertia moments of moving parts, starter moment, and external load moment. The In-cylinder pressure profile used in the model was obtained experimentally to increase the accuracy of the model. Pressure profiles were expressed mathematically using the Fourier series. The motion equations were solved by using the Taylor series method. The solution of the mathematical model was performed by coding in the MATLAB interface. Cyclic speed fluctuations obtained from the model were compared with experimental results and found compitable. A validated model was used to analyze the effects of in-cylinder pressure, mass moment of inertia of crankshaft and connecting rod, friction, and piston mass. In experiments for 1500, 1800, 2400, and 2700 rpm engine speeds, crankshaft speed fluctuations were observed as 12.84%, 8.04%, 5.02%, and 4.44%, respectively. In simulations performed for the same speeds, crankshaft speed fluctuations were calculated as 10.45%, 7.56%, 4.49%, and 3.65%. Besides, it was observed that the speed fluctuations decreased as the average crankshaft speed value increased. In the simulation for 157.07, 188.49, 219.91, 251.32, and 282.74 rad/s crankshaft speeds, crankshaft speed fluctuations occurred at rates of 10.45%, 7.56%, 5.84%, 4.49%, and 3.65%, respectively. The effective engine power was achieved as 5.25 kW at an average crankshaft angular speed of 219.91 rad/s. The power of friction loss in the engine was determined as 0.68 kW.


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