International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
International Journal of Research and Innovation in Thermal Engineering (IJRITE) SIMULATION AND ANALYSIS OF 4 STROKE SINGLE CYLINDER DIRECT INJECTION DIESEL ENGINE Kuricheti N. V. Sravan Kumar1, Muppidi Rambabu2. 1 Research Scholar, Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India. 2 Assistant Professor, Department of Mechanical Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.
Abstract Whenever an engine is designed and manufactured, it is tested to calibrate brake power, indicated power and friction power. Diesel engine simulation models can be used to understand the combustion performance; these models can reduce the effort, time while producing engines which fails to meet the requirements. In the present work a thermodynamic simulation model for the performance of a four stroke direct injection diesel engine is modelled. A zero dimensional model has been used as a model to investigate the combustion performance of a single cylinder direct injection diesel engine fuelled by high speed diesel. The numerical simulation was performed at different speeds and compression ratios. The pressure, temperature diagrams vs crank angle are plotted. The simulation model includes sub models for various frictional pressure losses, fuel inflow rate with crank angle. A solution procedure is developed for solving the available equations using numerical methods. An appropriate C++ code is written for brake power, friction power, indicated power, brake thermal efficiency are simulated. Experiment was conducted on available four stroke diesel engine and the model is validated. KEYWORDS: Simulation model, combustion performance, zero dimensional model, numerical simulation, indicated power, brake power, brake thermal efficiency, friction power. *Corresponding Author: Kuricheti N. V. Sravan Kumar, Research Scholar,Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India. Email: ksravankumar91@gmail.com Year of publication: 2016 Review Type: peer reviewed Volume: III, Issue : I
1. Moving the cylinder head 2. Variation of combustion chamber volume 3. Variation of piston deck height 4. Modification of connecting rod geometry (usually by means of some intermediate member) 5. Moving the crankpin within the crankshaft (effectively varying the stroke) 6. Moving the crankshaft axis MATHEMATICAL MODELLING PRESSURE LOSS MODELLING
Citation:Kuricheti N. V. Sravan Kumar, Research Scholar "Simulation And Analysis of 4 Stroke Single Cylinder Direct Injection Diesel Engine" International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET) (2016) 103-106 INTRODUCTION: Present days new ideas, which are not been discussed two decades ago were considered by automotive manufacturers. In particular, many leading automotive companies have approached practically the very complicated design ideas with different aspects of diesel/petrol engine design. These aspects have been under extensive theoretical and experimental investigations. The most important aspect of design is aimed to vary the engine compression ratio depending on load, speed, or both. Several trials have been done in that respect with extensive design, experimentation, and measurements. All attempts to change the compression ratio are achieved by one or more of the following concepts:
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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
PRESSURE LOSS The various pressure losses multiplied by volume and speed and converted into friction power are shown below.
FUEL INFLOW RATE MODELLING Mass flow rate of fuel=mass flow rate of air × fuel air ratio (stoichiometric) × equivalence ratio Volumetric efficiency is taken as 80%, pressure, temperature and gas constant are of intake air (approximated to atmospheric condition). PRESSURE AND TEMPERATURE ESTIMATION Writing the energy balance, the pressure variation with respect to crank angle we get as
Variation of friction power with compression ratio
It can be observed from figure that crank case mechanical losses, throttling losses and pumping losses are independent of compression ratio. Piston and blowby losses increase with increase in compression ratio almost linearly.
Variation of fuel consumption with brake power (experimental)
RESULTS:EXPERIMENTAL RESULTS Time taken for 20 cc of FC (s)
Net Load (kg)
BP (kW)
FC (kg/hr)
BSFC (kg/ kW-hr)
BTE (%)
IP (kW)
ME (%)
120
----
---
0.4965
---
---
0.875
---
95
1.35
1.004
0.6272
0.6247
13.25
1.879
53.43
78
2.55
1.896
0.7638
0.4028
20.54
2.771
68.42
64
3.75
2.788
0.9309
0.3339
24.78
3.663
76.11
45
4.95
3.68
1.324
0.3598
23
4.555
80.79
Calculation of friction power using Willan’s line method Friction power is found to be 0.875 kW which is 23.78% of the brake power at full load.
EMPIRICAL SOLUTION RESULTS Empirical relations directly give value of required parameter when the terms in the equations have proper units. The results obtained are fairly accurate when compared to the results obtained from experiments. The empirical relations listed and are coded in C++ including the terms with appropriate units to obtain friction power. Comparison of brake specific fuel consumption obtained from experimental and modelling solution.
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International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
NUMERICAL SOLUTION Indicated mean effective pressure =7.04961 bar Indicated power=4.8723 kW Friction power=0.7853 kW Hence brake power=4.8723-0.7853=4.087 kW EXPERIMENTAL RESULTS
Comparison of brake specific fuel consumption obtained from experimental and modelling solution
Brake power=3.68kW Friction power=0.875kW (noted down from Willan's line method then calculated) Indicated power=3.68+0.875=4.555kW Hence indicated mean effective pressure=6.5832 bar
P-V diagram
The P-V diagram obtained from numerical solution is following expected trend of an actual cycle. The steep rise and decrease of pressure indicate combustion zone of the engine.
Summary of results
The model gives fairly accurate results when we predict indicated power and brake power at full load. There is deviation of 7%, 11% and 10.25 % in results obtained from modelling solution to the predicted solution for indicated power, brake power and friction power respectively. CONCLUSIONS 1. The model predicts value of friction power and indicated power with an accuracy of 10%. 2. The engine must be operated at 75% of the load for the lowest possible brake specific fuel consumption.
Pressure vs crank angle
3. Increase in compression ratio is going to decrease the peak temperature. Even though in cylinder pressure increases with increase in pressure, emissions vary exponentially with temperature, hence emissions are reduced when compression ratio is increased. REFERENCES [1] M.MaherAbou Al Sood, Mahmoud Ahmed and M.Yousef Abdel Rahim. Rapid thermodynamic simulation model for optimum performance of a four-stroke, direct-injection, and variable-compression-ratio diesel engine, International journal of energy and environmental engineering, Springer open journal, 2012.
Effect of compression ratio on temperature
Compression ratio varied from 16 to 19 and its effect on temperature and pressure is studied. As compression ratio increases the peak value of pressure increases but peak value of temperature decreases. When compression ratio is increased the peak values of incylinder pressure and temperature are shifted towards TDC. SUMMARY OF RESULTS AT FULL LOAD
[2] C.Felsch, K.Hoffmann, A.Vanegas, P.Drews, H.Barths, D.Abel, and N.Peters. Combustion model reduction for diesel engine control design, 10.1243, 2009. [3] A.Sakhrieh, E.Abu-Nada, I.AlHinti, A.AlGhandoor, B.Akash. Computational thermodynamic analysis of compression ignition engine, International Communications in Heat and Mass Transfer, 37-299–303, 2010. [4] J.B. Heywood. Internal Combustion Engine Fundamentals, New York, McGraw-hill publications, 1988. 105
International Journal of Research and Innovation on Science, Engineering and Technology (IJRISET)
AUTHORS
Kuricheti N. V. Sravan Kumar, Research Scholar, Department of Thermal Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.
Muppidi Rambabu, Assistant Professor, Department of Mechanical Engineering, Aditya College of Engineering and Technology, Surampalem, Andhra Pradesh, India.
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