Analysis on a thermal barrier coated (TBC) piston in a single cylinder diesel engine powered by Jatropha biodiesel–diesel blends
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The objective of the present work is to enhance the performance of a diesel engine using a thermal barrier coated piston operated with Jatropha biodiesel–diesel blends. For thermal barrier coating, Yttria stabilized zirconia (YSZ) is preferred owing to its high heat insulation capabilities in comparison with other insulating materials such as mullite, zirconia, ceramics, magnesium silicate, silicon carbide etc. YSZ is coated via a plasma spray technique at around 200 µm thickness around the piston crown. The test fuel utilized are DF100 (100% diesel fuel), JB20NE (20% Jatropha biodiesel + 80% diesel fuel operated at normal un-coated engine) and JB20CE (20% Jatropha biodiesel + 80% diesel fuel operated at YSZ coated engine). Experimental results revealed that JB20CE has resulted in 10.6% increased brake thermal efficiency and 20.97% lowered brake specific fuel consumption since the YSZ coating acts as a potential insulator in retaining maximum heat inside the combustion chamber, lowering the energy losses followed by improved combustion efficiency, enhanced air–fuel mixture formation and higher performance. Emission wise, JB20CE operation resulted in lowered hydrocarbon and carbon monoxide emissions by about 41.67% and 33.33% due to improved fuel oxidation and effective combustion provided by YSZ insulation.
KeywordsThermal barrier Yttria stabilized zirconia Biodiesel Engine performance Combustion Emissions
Thermal barrier coated
Yttria stabilized zirconia
100% diesel fuel
20% Jatropha biodiesel + 80% diesel fuel
20% Jatropha biodiesel + 80% diesel fuel operated at normal un-coated engine
20% Jatropha biodiesel + 80% diesel fuel operated at YSZ coated engine
Brake thermal efficiency
Brake specific fuel consumption
Low heat rejection
Partially stabilized zirconia
Low temperature combustion
Exhaust gas recirculation
American society for testing and materials
Heat release rate
Crank angle degree
Exhaust gas temperature
In recent years, works were done with various biodiesels [1, 2, 3, 4] and various engine optimization techniques [5, 6, 7, 8, 9] for reducing fossil fuel consumption and lowering the exhaust emissions. Thermal barrier coating on various engine components has shown interest in recent years owing to resulting higher thermal and mechanical efficiencies as well as minimized emissions and improved fuel consumption. Through insulation, the heat rejected from the engine is subsequently lowered and hence the waste heat can be useful energy in oxidizing the soot precursors in hydrocarbon combustion thereby lowering the hydrocarbon (HC), carbon monoxide (CO) and Nitrogen oxides (NOx) emissions followed by lowered brake specific fuel consumption (BSFC). The thermal barrier coating (TBC) is effective in formulating the low heat rejection (LHR) engines. So far, several materials such as mullite, alumina, ceramics, spinel forsterite, zirconides, yttria-stabilized zirconia (YSZ) were used as potential coating materials as a thermal barrier coating. These materials were selected based on specific material properties such as higher melting point, minimized transformation between temperatures, lower coefficient of thermal expansion, chemical elements and match with metallic substrate etc. For the current experimentation, Yttria stabilized zirconia (YSZ) of 200 µm thickness is coated for providing thermal insulation in an internal combustion engine. There are various types of coating methods for providing insulation. For the present studies, plasma spray technique is adopted to coat YSZ, where the YSZ enters as powdered jet as the phase at a temperature of 8300 °C (15,000 °F), YSZ melts and steers into hot gas towards piston, where it solidifies as a thick coating.
Thermal barrier coating with NiCrAlY of 150 µm resulted in improvement of power, efficiency and lowering of fuel consumption as well as improvement in engine lifetime as a result of lowered surface temperature . Sharma  reviewed literature pertaining to the influence of coating materials in LHR engine of ceramic materials. It was observed that the ceramic coating has shown better as thermal barrier coating owing to its improved porosity and minimized stress in coating. Funatani et al.  examined the effect of Ni–Cr–Ce coating in the piston crown on diesel engine emissions and performance. They observed that CO and HC emissions were lowered while BTE increased with coating. Moreover, they found that Ni–Cr–Ce coating as TBC helps in increasing the engine brake power. Sivakumar and Kumar  examined the influence of YSZ coating as TBC in a single-cylinder direct injection (DI) compression ignition engine. Results revealed that, with coating, the heat loss is lowered by 10%, thermal efficiency increased by 5% and BSFC is lowered by 28%, HC and CO emissions were lowered by about 35.2% and 2.7% while NOx emissions increased up to 5.6%.
Taymaz et al.  reported improved fuel economy, minimized HC and CO emissions as well as lowered noise emissions as a result of lowered pressure rise rate and exhaust gas high energy content as a result of TBC. Kamo et al.  predicted that the ceramic-based TBC can enhance the BTE by 6% in comparison with the uncoated engine. Similar results with TBC has revealed that there was an increase in fuel economy by 37% , increase in indicated thermal efficiency by 14% , increase in indicated specific fuel consumption by 9% . Kamo et al.  experimented with diesel engine fuelled with TBC of YSZ around 0.1 mm thickness in piston and cylinder, 0.5 mm thickness coating of YSZ in cylinder liner and found that the fuel efficiency is increasing by about 6% at all the engine loads. Dhana Raju and Kishore  studied the diesel engine characteristics of operated with various tamarind biodiesel blends when the piston crown coated with zirconium of 150 μm thickness using a plasma spray method. The experimental test results revealed positive diesel engine characteristics than the uncoated piston at the same engine operating conditions.
Yao and Qian  studied the thermal analysis of a natural gas-powered diesel engine with nano-ceramic coated piston at different load conditions. They used aluminium alloy-piston coated through partially stabilized zirconia (PSZ) ceramic layer of 200-μm thickness. They found with a TBC of the piston, significant enhancement in temperature of combustion chamber, thermal efficiency and a considerable decrease in harmful emissions at all load conditions. Selvam et al.  examined the effectiveness of ceramic-coated piston on the performance and combustion characteristics of a direct injection diesel engine. Yttria-stabilized zirconia (YSZ) was applied as TBC material over the piston top surface with the use of a plasma spray coating technique. They noticed higher thermal efficiency and lower brake specific fuel consumption with the coated piston than the non-coated piston at full load condition for tested fuel samples. However, they also observed that an increase in NOx emissions with the coated piston.
Agarwal et al.  reviewed about the fundamental aspects of low temperature combustion engines evaluation, its origin of thermal barrier approach and future challenges with respect to internal combustion engines. They also revealed the detailed insights for fuel requirements and fuel injection systems for low temperature combustion (LTC) engines. The authors also provided an in-depth review of emission characteristics of LTC engines and suggested the LTC engine technology was a promising option for future automobile applications. Jena et al.  examined performance, emission and combustion characteristics of a DI diesel engine with YSZ coated on the piston crown and engine valves. They used ferric chloride as a fuel catalyst to diesel with coated piston and also non-coated piston. The application of ferric chloride on zirconia coated piston shown 2.7% enhancement in BTE and 8.3% decrease in BSFC when compared to the normal piston at full load operation. Further, they found significant reductions in CO, HC and smoke opacity with marginal increment in NOx emission.
Kumar and Veerabhadhrappa  studied the TBC over engine cylinder head, valves and piston crown to minimize the heat losses and improve the performance parameters of the diesel engine. Plasma spray method was used for coating ceramic material over the hot spot engine components. From the experimental test results, they found considerable enhancement in thermal efficiency with the coated piston than the normal piston at all load operations of the diesel engine with significant reductions in exhaust emissions. Krishnamani et al.  performed tests on LHR diesel engine powered by rapeseed biodiesel and diethyl ether to improve the performance parameters and reduce the exhaust emissions. They reported that overheated engine components such as inlet valve, piston crown, exhaust valve, cylinder head of diesel engine coated with lanthanum zirconate with the application of plasma spray technique. They noticed from the experimental test results that substantial improvement in thermal efficiency for the test specimens and also greater reductions in emissions such as CO and HC by 10% and 18% respectively for diethyl ether (DEE) addition at 10% concentration to 20% rapeseed methyl ester than the neat rapeseed methyl ester at full load condition. Kulkarni et al.  studied the characteristics of the diesel engine when the combustion surfaces like a piston, cylinder head and engine valves were coated with ceramic material making the combustion chamber as fully adiabatic or low heat rejection diesel engine. They conducted tests on a DI diesel engine powered with mahua oil biodiesel at different exhaust gas recirculation (EGR) rates such as 0%, 5%, 15% and 20% with and without ceramic coating. The low heat rejection yielded considerable enhancement in thermal efficiency as well as significant reductions in engine tailpipe emissions than an uncoated diesel engine.
Rao et al.  examined the influence of a thermal barrier coating on the dual fuel diesel engine when hot engine parts of the combustion chamber were coated with Mullite (a mixture of aluminium oxide and silicon oxide). They were used diesel as pilot fuel and compressed natural gas was used as a primary fuel at different flow rates such as 5, 10 and 15 l per minute to investigate the performance, combustion and emission characteristics. They found mullite coating on combustion chamber parts revealed a positive effect on the characteristics of the dual-fuel diesel engine. Also, they noticed greater reductions in exhaust emissions with a coated piston of dual-fuel engine at operating conditions except nitrogen oxide emissions. Similar test results reported by Senthil et al.  about the emission and performance characteristics of PSZ coated diesel engine powered with nerium biodiesel blends. The insulation effect of coating over engine components increased the thermal efficiency of 3.8% than the uncoated diesel engine with nerium biodiesel blend. Babu et al.  stated the use of 20% mahua oil biofuel as a viable alternative fuel for low heat rejection of diesel engine applications. The insulating material of aluminium oxide coated over piston, valves and cylinder walls with a thickness of 0.3 mm by plasma spray technique. They inferred that 6.2% increase in thermal efficiency and 8.5% reduction in fuel consumption with the coated engine than the unmodified diesel engine with neat diesel. The engine tailpipe emissions were also reduced with the coated engine at all operating conditions.
Based on the critical literature analysis, it is observed that the LHR engines with TBC on engine components with YSZ coating are effective in improving the BTE and BSFC. However, certain literature pointed out that with TBC coating, the NOx emissions were prone to increase due to higher in-cylinder temperatures prevailing inside the combustion chamber. In the present experimental work, the piston crown is coated with YSZ (at a thickness about 200 µm) using plasma spray coating method and analyzed in diesel engine powered by JB20 (20% Jatropha biodiesel + 80% diesel fuel) for combustion, performance and emission characteristics.
2 Experimental material and methods
2.1 Yttria stabilized zirconia coating
Advantages and disadvantage of insulating materials
Phase transformation occurs at 1273 K
Higher thermal conductivity
No Oxygen transparency
Lower coefficient of thermal expansion
No Oxygen transparency
Crystallization occurs between 1023 and 1273 K
Improved corrosion resistance
Lower coefficient of thermal expansion
Low thermal conductivity
Higher Young’s modulus
Lower coefficient of thermal expansion
Low thermal conductivity (2 W/(mK))
Higher toughness fraction
Lower melting point (1600 °C)
Higher melting point (2800 °C)
Sintering occurs above 1473 K
Lower thermal conductivity (2 W/mK)
Phase transformation occurs at 1443 K
Higher coefficient of thermal expansion (107/°C)
Plasma coating specifications
Metco 3 MB plasma spray
Powder feed rate (gpm)
Hydrogen flow rate (Psi)
Organ gas flow rate (lpm)
Organ gas pressure (Psi)
Spraying distance (inches)
2.2 Jatropha biodiesel preparation
Fuel properties of diesel and Jatropha biodiesel
Jatropha biodiesel (JB100)
Density @ 20 °C (kg/m3)
Lower heating value (kJ/kg)
Kinematic viscosity at 35 °C (mm2/s)
Flash point (°C)
130 °C min
Carbon residue (% by wt)
Iodine value (g I2/100 g)
C/H ratio (by v/v)
2.3 Selection of test engine
4.4 kW @ 1500 rpm
Four stroke, vertical diesel engine
Number of cylinder
Bore diameter and stroke length
87.5 mm and 110 mm
23 deg bTDC (rated)
The diameter of the nozzle hole
No. of nozzle holes
Combustion chamber geometry
2.4 Instrumentation and measuring methods
The present experimental setup uses fuel injection of MICO and a pressure transducer of piezo-electric mounted on cylinder head for recording the heat release rate and the in-cylinder pressure during the operation. Exhaust gas analyser (QRO-402) measures the CO, HC, and NOx emissions. Smoke meter (AVL437C) measures the smoke opacity. The engine load is connected with eddy current dynamometer. The engine load changed from lower to higher load by varying the current supply. Experimentations were done with different engine loads ranges from 0 to 100%. The air-cooled diesel engine uses SAE40 lubricating oil with a capacity of 3.7 litres.
3 Results and discussion
Experiments were done on DF100 (100% diesel fuel), and JB20 (20% Jatropha biodiesel + 80% diesel fuel) in a normal engine and were compared with that of YSZ coated engine fuelled with JB20. The engine load is varied from 0 to 100% at intervals of 25%. The heat release rate and in-cylinder pressure were analyzed at 100% load condition. The maximum pressure rise is recorded at every load so that the peak pressure rise at every load can be analyzed.
3.1 Combustion characteristics
3.1.1 In-cylinder pressure
3.1.2 Heat release rate
3.1.3 Ignition delay
3.1.4 Combustion duration
3.1.5 Brake thermal efficiency
3.1.6 Brake specific fuel consumption
3.1.7 Exhaust gas temperature
3.2 Emission characteristics
3.2.1 Carbon monoxide
3.2.3 Nitrogen oxides
3.2.4 Smoke opacity
In comparison with JB20NE, the JB20CE exhibits 20.97% lowered BSFC and 10.6% higher BTE owing to the pooled effect of improvement in air–fuel mixture formation, improved combustion efficiency and lowered heat loss provided by YSZ coating thereby maximum in-cylinder pressure retained in the combustion chamber.
Emission wise, JB20CE has lowered HC (by 41.67%), lowered CO (by 33.33%), lowered NOx (by 15.94%) and lowered smoke (by 15.08%) respectively as a result of improved oxidation of soot precursors and higher in-cylinder temperature inside the combustion chamber.
Combustion wise, JB20CE has higher in-cylinder pressure of about 71.69 bar and improved heat release rate of about 69.52 J/degCA which could be attributed to lowered delay period and combustion duration favouring the increase in premixed combustion phase due to YSZ coating providing maximized heat retainment inside the engine.
The authors have been equally contributed for this research work.
Compliance with ethical standards
Conflict of interest
The authors declare no competing financial interest and non-financial interest.
- 1.Alagu K, Venu H, Jayaraman J, Raju VD, Subramani L, Appavu P, Dhanasekar S (2019) Novel water hyacinth biodiesel as a potential alternative fuel for existing unmodified diesel engine: performance, combustion and emission characteristics. Energy 179:295–305. https://doi.org/10.1016/j.energy.2019.04.207 CrossRefGoogle Scholar
- 4.Venu H, Venkataraman D, Purushothaman P, Vallapudi DR (2019) Eichhornia crassipes biodiesel as a renewable green fuel for diesel engine applications: performance, combustion, and emission characteristics. Environ Sci Pollut Res 26(18):18084–18097. https://doi.org/10.1007/s11356-019-04939-z CrossRefGoogle Scholar
- 5.Appavu P, Ramanan MV, Venu H (2019) Quaternary blends of diesel/biodiesel/vegetable oil/pentanol as a potential alternative feedstock for existing unmodified diesel engine: performance, combustion and emission characteristics. Energy 186:115856. https://doi.org/10.1016/j.energy.2019.115856 CrossRefGoogle Scholar
- 7.Jayaraman J, Alagu K, Venu H, Appavu P, Joy N, Jayaram P, Mariadhas A (2019) Enzymatic production of rice bran biodiesel and testing of its diesel blends in a four-stroke CI engine. Energy Sour Part A Recover Utilization Environ Effects. https://doi.org/10.1080/15567036.2019.1671554 CrossRefGoogle Scholar
- 10.Azadi M, Baloo M, Farrahi GH, Mirsalim SM (2013) A review of thermal barrier coating effects on diesel engine performance and components lifetime. Int J Auto Eng 3(1):306–317Google Scholar
- 11.Sharma RK (2014) Integrated review of thermo-physical properties of different ceramic coatings to make them suitable for internal combustion engines. Global J Res Eng 13(10):1–5. https://engineeringresearch.org/index.php/GJRE/article/view/967
- 12.Funatani KKPA, Kurosawa K, Fabiyi PA, Puz MF (1994) Improved engine performance via use of nickel ceramic composite coatings (NCC coat) (No. 940852). SAE Tech Paper. https://doi.org/10.4271/940852
- 15.Kamo R, Mavinahally NS, Kamo L, Bryzik W, Schwartz EE (1999) Injection characteristics that improve performance of ceramic coated diesel engines (No. 1999-01-0972). SAE Tech Paper. https://doi.org/10.4271/1999-01-0972
- 16.Bruns L, Bryzik W, Kamo R (1989) Performance assessment of US. Army truck with adiabatic diesel engine (No. 890142). SAE Tech Paper. https://doi.org/10.4271/890142
- 17.Wallace FJ, Way RJB, Vollmert H, (1979) Effect of partial suppression of heat loss to coolant on the high output diesel engine cycle (No. 790823). SAE Tech Paper. https://doi.org/10.4271/790823
- 18.Havstad PH, Garwin IJ, Wade WR, (1986) A ceramic insert uncooled diesel engine (No. 860447). SAE Tech Paper. https://doi.org/10.4271/860447
- 19.Raju VD, Kishore PS (2017) Investigation on green fuel design for low heat rejection diesel engine in sustaining the energy and environment. In: International Conference on Trends and Advanced Research in Green Energy Technologies, ICTARGET-2017, 30th & 31st March, 2017Google Scholar
- 25.Krishnamani S, Mohanraj T, Kumar KM (2016) Experimental investigation on performance, combustion and emission characteristics of a low heat rejection engine using rapeseed methyl ester and diethyl ether. Indian J Sci Technol 9(15):01–09. https://doi.org/10.17485/ijst/2016/v9i15/87322 CrossRefGoogle Scholar
- 30.Balkrishna KK, Prakash SP, Hebbal O (2013) Experimental investigation of performance and combustion characteristics on a single cylinder lhr engine using diesel and multi-blend biodiesel. Int J Res Eng Tech 2:120–124Google Scholar