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Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
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Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study R. Udayakumar a, N.K. Miller Jothi b, Saurav Saboo a, Naseef Sadhik a a b
Department of Mechanical Engineering, Bits Pilani Dubai Campus, Dubai International Academic City, Dubai, UAE Department of Mechanical Engineering, Mekelle University, Ethiopia
a r t i c l e
i n f o
Article history: Received 13 October 2019 Received in revised form 8 November 2019 Accepted 26 December 2019 Available online xxxx Keywords: CI engines Rankine cycle Low heat rejection engines Ceramic coating Steam turbocharging
a b s t r a c t In an ordinary internal combustion engine only one third of the total heat liberated by the combustion of fuel is converted in to useful work. The exhaust gases leaving the engine are generally at a high temperature and hence they carry away a good amount energy. Substantial amount of energy is rejected via heat through the cooling system. An improvement in fuel economy could be seen, if the rejected energy to the coolant system could be used. LHR engines are the one in which the walls of the combustion chambers are coated with ceramic materials so that the heat loss to the coolant is very much reduced. It is thought that due to the adiabatic nature of the combustion chamber walls the energy available inside the cylinder for conversion in to useful work is more and this will improve the efficiency of the engine. But it is a wellknown fact that only a marginal increase in the thermal efficiency of the engine is noticed. The reduction of heat loss from the combustion chamber of diesel engines improves fuel efficiency only by 3 or 4 per cent. The major amount of energy goes with the exhaust gasses as the gasses leave the engine at a very high temperature. For more than a decade, many researchers have pursued the implementation of thermal barrier coatings (TBCs) in diesel engines to increase the combustion temperature and to increase the engine performance. In this work a novel method of recovering energy from the exhaust and to improve the overall efficiency of the engine is presented. The effect of thermal barrier coatings on diesel engine energy balance system is studied. Improving the performance of the engine by recovering heat from exhaust with Rankine cycle is investigated. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Recent Advances in Materials & Manufacturing Technologies.
1. Introduction A conventional internal combustion engine has the ability to convert only one-third of the heat energy from fuel into useful work, rest being lost to coolant and lost through exhaust. To improve the performance of the engine and to make use of most of the energy available through fuel, engineers are forced to research ways to recover these high amounts of energy lost. One successful way of recovering loss through exhaust is by installing a turbocharger in the engine. A turbocharger consists of a turbine and a compressor. The exhaust gases expand in the turbine, which in turn drives the air compressor. Air compressor boosts the intake pressure of the engine, hence improving its power output and performance. A typical turbocharger can improve the performance of the engine up to 15%. Most of
the modern-day automobiles make use of this technology as exhaust energy recovery system. The main drawback of this technology is that it uses pressure energy of the exhaust whereas maximum amount of energy in the exhaust is present in the form of heat. Consequently, engineers came up with steam turbocharging. It is similar to normal turbocharging except it uses bottoming Rankine cycle. Exhaust energy transfers its heat to water through a heat exchanger, which converts into steam and drives the turbine. This technology is much more efficient than the conventional turbocharger technology but has two major drawbacks, one being its intricate and complicated design, and the other being the weight increase of the car upon installation. Energy recovery from coolant is a much more difficult and inefficient task. Hence, engineers came up with the technology to minimize heat loss through coolant and thus low heat rejection
https://doi.org/10.1016/j.matpr.2019.12.338 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Recent Advances in Materials & Manufacturing Technologies.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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engines were introduced. The pioneers of this technology were able to improve the performance of the engine by 7%. By coupling Rankine cycle exhaust energy recovery system with low heat rejection engines, a very efficient engine can be designed with maximum use of the energy available to it. The main reason for this report is to discover the power balance at varied engine loads and speeds in a ceramic-covered diesel engine and scrutinize the performance change by coupling the engine with a Rankine cycle. Examinations were conducted in a six cylinder, turbocharged, inter-cooled diesel engine. 2. Low heat rejection engine concept The concept of low heat rejection engine is fairly old. Researchers and engine designers have long been aware that increasing the combustion temperature and reducing the heat losses through the combustion chamber walls will increase thermodynamic efficiency of the engine. The diesel engine with its combustion chamber walls insulated by ceramic coatings is referred to as Low Heat-Rejection (LHR) engine or semi adiabatic engine. The LHR engine has been developed basically to improve fuel economy by eliminating the cooling losses and converting part of the increased energy available in the exhaust gases into shaft work using the turbochargers. A good amount literature is available on the overall performance of the engine, durability of the coatings and operation of LHR engines with alternate fuels Morel et al., have discussed a new concept of the LHR engine and they have studied the performance of the engine with the turbochargers [1]. The authors [2,3] discussed about the LHR engines and they have concluded that the use of Thermal Barrier Coatings (TBCs) lead to multifuel capacity, better fuel efficiency, and higher power density due to higher chamber combustion temperature in diesel engines. The introduction and development of advanced ceramic materials and the coating techniques in the past few decades have made lot of progress in the research especially with respect to Diesel engines. In 1975, the U.S. companies like Cummins and TACOM have initiated an ‘‘adiabatic” program in engines and significant progress has been made in the field after that [4,5]. In addition, companies like Isuzu Motors [6,7], Ford Motor Company [8,9] have conducted various experimental work including the endurance tests with the LHR Engines. Most of them have stated that heat transfer is reduced by thermal insulation, but none have delivered such results in terms of engine performance or efficiency [4,5]. Two main problems associated to the development of the LHR engines are the strength and wear resistance of the various engine components at excessive temperatures. Generally, the traditional lubricants and metals neglect to perform at raised temperatures though, an alternative can be provided by using ceramic materials. These materials have given a significant push in further researching LHR in recent years. The different materials that are attempted are partially stabilized oxide of zirconium, (ZrO2); oxides of iron, aluminium, and chromium (Fe2O3, Al2O3, and Cr2O3); and carbides and nitrides of silicon (SiC and Si3N4). The various aspects of Low Heat Rejection Engines using different ceramic materials are presented in detail in the literature [10 –13]. 2.1. Constraints in ceramic coating The mismatch in the coefficient of thermal expansion is a severe constraint for proper adherence of the coating. This difficulty has been successfully overcome by introducing an intermediate expansivity-compensating layer between metal and ceramic. This intermediate layer (of thickness 0.15 mm) absorbs stresses between ceramic and metal produced due to thermal cycling.
When a plasma sprayed coating of thickness of 0.05 mm is given using partially stabilized zirconia (PSZ) on a metal with an intermediate layer of thickness 0.15 mm, the temperature drops from 1450 °C to 700 °C. Ceramic coating of thickness 0.15 mm to 1.0 mm given to the combustion chamber increases the operating temperature considerably. 2.2. Various types of coating techniques The following are the various coating techniques a. b. c. d. e. f.
Flame spraying Electric arc spraying Chemical vapor deposition and physical vapor deposition Detonation gun Jet kote Plasma Spraying
2.3. Plasma Spraying: Plasma spraying uses an electric arc maintained in a nozzle and an electrode as a heat source. This arc heats the stream of inert gases generally argon, hydrogen, nitrogen, or helium through a very high temperature more than 20,000 °C. This causes dissociation and ionization of the gas molecules. A large increase of gas volume occurs due to high temperature so that gas flow from the nozzle is at high speed (1000 m/s). The coating material is injected in powder form with the aid of a carrier gas Argon into this high energy plasma jet. This is the commonly used method in the engine applications. 2.4. Types of coating materials and characteristics There are different materials available for coating, among them the following are studied: a. Syalon (Si – Al – O – N): The name derives from the elements of Si – Al – O – N, and at its latest formulation, the mixture is stronger than steel, diamond hard, light as Al. It has exceptional resistance to wear and thermal shock. It retains its compressive and tensile strength at temperatures up to 1400 °C, while individual properties are not necessarily outstanding. b. Silicon Nitride (Si N): Silicon nitride is well known for its unique characteristics, such as, high strength at high temperatures, excellent wear resistance, very good thermal shock resistance and resistance to corrosion. Values in excess of 1000 MN/m2 for flexural strength are obtained and can be maintained to the temperature of about 1000 °C. Where ceramics operate to surpass metallic in strength properties, considerable degradation of strength occurs. The temperature strength degeneration is due to onset of slow crack growth. These properties should make Si N a material for heat engines and it has been called the ceramic of the decade in last ten years. c. Silicon Carbide: Silicon carbide is known for its exceptionally high oxidation resistance up to 1000–1200 °C. It is a strong candidate for structural ceramic applications such as in turbo-automotive parts. Silicon Carbide based ceramic materials include – hot pestered SiC, reaction sintered (or bonded) SiC, silicon carbide and silicon composites. Hot pestered carbide provides the highest strength avail-
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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able (550 MN/m2 at 1375 °C) over the other silicon carbide based materials. At a working temperature of 1300 °C, self-bonded silicon carbide is also a potentially viable material, although it does suffer from a short fall in properties above 1400 °C due to melting of free silicon which is available in the material. d. Hot Pressed Silicon Carbide Material (HPSN): HPSN is produced by either uniaxial or hot iso-static pressing of Silicon carbide powder with Alumina or Boron and Carbon to obtain a wide range of room temperature strength materials, which has the following properties. High temperature strength, creep fracture toughness, high fracture resistance coefficient and excellent thermal shock and corrosion resistance.
engine. Therefore, lowering or complete removal of this pumping loss seems to be the primary objective of this system. Their relationship can be shown as,
BMEP ¼ IMEP þ PMEP FMEP
where PMEP is the pumping mean effective pressure, IMEP is the indicated mean effective pressure, FMEP is the friction mean effective pressure, BMEP is the brake mean effective pressure, which is a standout amongst the most critical parameters of IC engine power performance. Fig. 1 depicts for the exhaust turbocharging system. From the figure, the relationship around PMEP, exhaust and intake pressure is given as,
PMEP ¼ P2 P3 Pcylinder port loss e. Reaction Bonded Silicon Nitride (RBSN): Reaction bonded silicon nitride possesses appreciable porosity, but they are cheap and easy to fabricate from silicon powder by compaction using cold pressing, flame spraying, slip-casting or plastic-binder molding techniques. It maintains its strength to temperature beyond 1400 °C, exhibits creep rate significantly below those of HPSN. f. Partially Stabilized Zirconia (PSZ):
ð1Þ
ð2Þ
If intake pressure of the IC engine is more than the exhaust pressure, pumping mean effective pressure will be positive. On the other hand, if the opposite situation is considered, a negative PMEP value will be obtained, and IC will need to dissipate some energy to overcome this [2]. This is more prevalent in exhaust turbocharged engines as exhaust pressure is on the high side and on some instances, energy lost through pumping is more than energy recovered. The Fig. 2 shows the PV diagram for the turbocharged engine. These engines generally reduce the PMEP so that the net power output can be increased.
Toughened partially stabilized zirconia (PSZ) ceramics possess several good properties so that it is used in a variety of advanced engine components, in particular for adiabatic engine systems. Magnesia-partially stabilized Zirconia (Mg-PSZ) is one of the toughest ceramics possessing excellent insulating, high strength, good thermal shock and wear resistance properties. In addition, PSZ has a thermal expansion and elastic modulus similar to iron and steel. As a result of the combination of these thermal and mechanical properties it is suitable for application such as cylinder liners, valve guide, valve seats, piston caps, hot plates and tapped inserts. 3. Exhaust turbocharging Exhaust turbocharging uses exhaust gases to boost the engine intake pressure. In this system, exhaust gases from cylinders drive the turbine, which in turn drives the air compressor. Therefore, exhaust turbocharging is a kind of immediate system to recover energy losses from exhaust and increase performance. At present, it is the most widely used technology and can be found in all the cars that use exhaust energy recovery system. But it is a very inefficient of exhaust energy recovery system with its drawbacks mentioned as follows
Fig. 1. The schematic diagram of the exhaust turbocharging system.
As the flue gas expands in turbine exhaust back pressure is increased and therefore increase the losses; At lower RPMs this system is inefficient as exhaust pressure is low and at higher RPMs exhaust pressure is too high that some amount of energy has to be discarded through the wastegate; As a part of exhaust energy recovery system, the system in itself is inefficient as it uses pressure energy of the exhaust whereas most of the energy is available in the form of heat; Matching process of the turbocharger and internal combustion engine is a hard process as internal combustion engine exhaust parameters fluctuate frequently. 4. Pumping loss of the exhaust turbocharged engines As reported before, the greatest drawback of an exhaust turbocharging system in an IC engine is the high pumping losses associated with it, which significantly influences efficiency of the IC
Fig. 2. P-V diagram of an in-cylinder cycle for exhaust turbocharging engine.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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5. IC engine steam turbocharging The drawbacks of the exhaust turbocharging are discussed in the Section 3. Most of the problems presented can be overcome by adopting the new approach which is called steam turbocharging. This is based on the Rankine steam cycle. It will be an indirect method in which the heat from the exhaust gasses will be transferred to a steam generator. The steam generated in it will be allowed to expand through a steam turbine which will be used for supercharging the engine. The schematic diagram of steam turbocharging is shown in the Fig. 3. It consists of a heat exchanger which extracts heat from the exhaust gases and is transferred to the water in the steam generator and steam is produced. In addition to a normal turbocharged engine, it contains a motor where the excess energy recovered can be stored and used for different purposes. As mentioned before the cycle followed is Rankine Cycle with a tank, pump and a heat exchanger. The features of the various modes of operation are explained below. Starting, low speed and low load mode: When the IC engine is started and running at low speed or running at low load the heat energy available in the exhaust gasses may not be sufficient to produce enough steam to run the steam turbine. Hence during such periods, the air compressor will be driven by the electric motor in the system. High Speed and High load mode: During high load and highspeed conditions of the engine, the heat energy available in the exhaust gasses will be very high and by recovering the energy it is possible to run the steam turbine. Also, there will be additional power that will be available from the steam turbine over and above which is required to run the air compressor and this excess power can be then utilized to run the motor which will act as an alternator. The electric power thus produced can be stored in the batteries. This power will be utilized to run the compressor during the low speed and low load conditions of the engine. Basic analyses of the characteristics of the steam turbocharging are as follows Inter connecting the motor with the output shaft of the engine has many advantages. It ensures that turbocharging system will have better transient response for the different operating conditions. The turbo lag can be very much reduced. The efficiency of
the energy recovery system will also be increased very much. Even at starting and low speed operating conditions the engine will have good amount of power boost. In a conventional exhaust gas turbocharging system, the exhaust gas parameters fluctuate very much with respect to the various operating conditions of the engine. The system will not be able work in the optimum conditions. On the other hand, the operating parameters of the proposed steam turbocharging system such as the steam pressure& temperature, the flow rate etc. can be accurately controlled by the controls incorporated in the engine system. Hence the proposed system will operate in near optimum conditions at all the time. In steam turbocharging the bottom steam cycle is connected to the working cycle of the engine through transfer of heat instead of transmission through pressure. Hence it does not put any restriction on the exhaust conditions of the engine. The exhaust pressure of steam turbocharging engine can be largely reduced compared to exhaust driven turbocharging system. This may avoid exhaust blow down and increase the engine power output. The pumping work of steam turbocharged engine during the intake and exhaust process may also change from negative to positive.
6. Engine analysis A low heat rejection engine is chosen for the current research which is 4 stroke, 6 cylinder, 6-liter turbocharged engine. Its specifications are given in Table 1. The energy distribution of normal IC engine and ceramic coated IC low heat rejection engine tests are shown in Figs. 4–6. It speaks to the variety of the power offset at three different loads of low, medium and high load. Up to 40% load may be considered as low load and 40–70% may be considered as medium load and above 70% may be considered as high load operations. At various rpms and loads, the diminishment in heat dismissal for the most part
Table 1 Specifications of the engine. Engine type Maximum Power Bore Stroke Compression Ratio Injection Timing (°CA) Displacement volume
Ford 6.0, T/CI, DI, 4 stroke and 6 cylinder 136 kW @ 2400 rpm 104.77 mm 114.9 mm 16.5:1 27° BTDC 5.947 L
Fig. 3. Schematic diagram of steam turbo charging system.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
R. Udayakumar et al. / Materials Today: Proceedings xxx (xxxx) xxx
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Fig. 4. Energy distribution in low load condition.
Fig. 5. Energy distribution in medium load conditions.
Fig. 6. Energy distribution in high load conditions.
brought about an increment in exhaust energy. Results are shown as follows:
7. Results and discussion To recover the energy available in the exhaust by Rankine cycle, energy from the exhaust gases must first be transferred to water through heat exchanger. For designing the heat exchanger and to determine the energy acquired by water we first find the exhaust parameters. With the help of the brake specific fuel consumption (kg/kw-h), the mass flow rate of fuel is calculated and from the air-fuel ratio used by the engine the air flow rate to the engine is
calculated. The mass flow rate of exhaust gases is calculated by mass flow rate of the fuel plus mass flow rate of the air at a particular speed of the engine. These values are then used to find the mass flow rate of steam that is produced in the heat exchanger and entering the turbine. Heat transfer between exhaust and water takes place in a shell and tube heat exchanger. By following the standard procedure for designing the heat exchanger the heat transfer area is calculated as 0.401 m2 using NTU method. Number of tubes are found to be about 28 with outside diameter of tube as 0.012 m and length of the tube as 0.38 m. Number of baffles were taken as 15 with baffle spacing was calculated as 0.0271 m. Number of passes were taken as 1 with tube clearance as 0.096 m. The efficiency of turbine
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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Table 2 Output of the software at the engine speed of 1800 rpm. Steam inlet condition Parameter Pressure Temperature Phase Steam flow rate Sp.Enthalpy Sp.Entropy Energy Flow
Unit 39.48 bar 400 °C Gas 226.7 kg/hr 3212 kJ/kg 6.7574 kJ/kgK 738539 kJ/hr
Power output
Steam outlet condition
(KW) 18.6 18.6 18.6 18.6 18.6 18.6 18.6
Parameter Pressure Temperature Phase Steam flow rate Sp.Enthalpy Sp.Entropy Energy Flow
and generator is 80% and 95% respectively. With these inlet values of steam, power that could be produced in the steam turbine is calculated using the steam turbine software by EERE advanced manufacturing office. The following is the output of the software at the engine speed of 1800 rpm which is given in Table 2 and similarly for other speeds of 2000 rpm; 2200 rpm and 2400 rpm the values are obtained from the software. 7.1. Power generation and efficiency The Fig. 7 shows generated power with respect to the different rpm. We can deduce from this graph that at higher rpms we got
Unit 4.9 bar 198.5 °C Gas 226.7 kg/hr 2847 kJ/kg 6.9584 kJ/kgK 633033 kJ/hr
more power from exhaust than at lower rpms as exhaust energy is more at higher rpms. The air compressor is driven by the generated power. Maximum power attained is calculated to be as high as 36.1 kW for the engine and the exhaust heat exchanger combination. At higher rpms excess energy left, after utilizing the rest to drive the air compressor, can be stored and used to drive air compressor at lower rpms when energy available is not high enough to drive the air compressor, as well as can be used for other miscellaneous things. Therefore, there is no turbo lag and a constant intake pressure boost is supplied to air entering the cylinder. The Fig. 8 depicts the variation of efficiency with respect to the different rpm. Efficiency is the ratio of power obtained from turbine to the brake power available to the engine. We can conclude from this graph that efficiency is higher at higher rpm and goes up as high as 26.5% whereas in normal turbocharged engines maximum attainable efficiency could reach as high as 15%. The rate of increase in efficiency shows that this system is better at high rpm conditions than at lower rpm conditions.
8. Conclusion This study presents an idea of steam turbocharging which helps in increasing the overall efficiency and the inlet pressure of the IC engine. Compared with other techniques such as exhaust turbocharging, it provides many advantages and can successfully enhance the utilization of the IC engines. Based on the research the following conclusions are drawn. Fig. 7. Generated power in the steam turbine at various engine speeds.
Fig. 8. Efficiency versus engine speed.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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Because exhaust turbocharging system reuses IC engine exhaust energy through a system after the exhaust manifold, its exhibitions are just dictated by exhaust parameters, particularly the exhaust pressure. Notwithstanding, steam turbocharging systems recoups IC engine exhaust energy focused around heat transfer and steam power cycle. What’s more important is its performances could be enhanced by selecting bottom cycle system parameters, for example, steam pressure and stream rate. Besides, this engineering could be straightforwardly connected on IC engine without altering its principle structure. When the steam turbocharging system is connected to IC engine, both the power and warming up of IC engine are improved compared to exhaust turbocharging engine. At the pace of 2400 revolutions/min, power available from turbine was calculated as 36.1 kW, which is 26.5% of its brake power. This clearly shows that the steam turbo charging has great energy saving potential. Since exhaust energy is very high in low heat rejection engines, turbocharging using Rankine cycle finds its best use in recovering the heat from exhaust. This technology will surely be widely used in the field of automobiles in the coming future. From this research, it is safe to conclude that this technology has a lot of importance in the upcoming years. With efficiencies more than double of the exhaust energy recovery systems that are used today, this technology finds a large scope in the near future. Also, it is the only technology that reduces energy losses from both exhaust and coolant thus, maximizing the use of energy available. The only shortcoming it faces today is its intricate and complex design as automobile manufacturers find it difficult to design it in their products. Also, it adds a considerable amount of weight to the car and increases the price of production thus making the manufacturers reluctant in using this technology in the present day. However, as fuel will get scarcer, its prices will steep, turning pro-
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duction cost less important than the running cost of the automobile, making this technology indispensable for the future. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] T. Morel, S. Wahiduzzaman, E.F. Fort, D.R. Tree, D.P. DeWitt, K.G. Kreider, Heat Transfer in a Cooled and an Insulated Diesel Engine, SAE Paper, Detroit, MI, 1989, p. 9. [2] P. Ramaswamy, S. Seetharamu, K.B.R. Varma, N. Raman, K.J. Rao, thermomechanical fatigue characterization of zirconia (8% Y2O3-ZrO2) and mullite thermal barrier coatings on diesel engine components: effect of coatings on engine performance, Proc. Instn. Mech Eng. 214 (729–742) (2000) 10. [3] D. Zhu, R.A. Miller, Thermal Barrier Coatings for Advanced Gas Turbine and Diesel Engines, NASA/TM, 1999, p. 11. [4] W. Bryzik, R. Kamo, TACOM/Cummins Adiabatic Engine Program, SAE Paper, Detroit, MI, 1983, p. 12. [5] P. Badgley, R. Kamo, W. Bryzik, E. Schwarz, NATO Durability Test of an Adiabatic Truck Engine, SAE Paper, Detroit, MI, 1990, p. 13. [6] M. Woods, W. Bryzik, E. Schwarz, 100 Hour Endurance Testing of a High Output Adiabatic Diesel Engine, SAE Paper, Detroit, MI, 1994, p. 14. [7] H. Kawamura, H. Matsuoka, Low Heat Rejection Engine with Thermose Structure, SAE Paper, Detroit, MI, 1995, p. 15. [8] H. Kawamura, Development Status of Isuzu Ceramic Engine, SAE Paper, Detroit, MI, 1988, p. 16. [9] W.R. Wade, P.H. Havstad, V.D. Rao, M.G. Aimone, C.M. Jones, A Structural Ceramic Diesel Engine - The Critical Elements, SAE Paper, Detroit, MI, 1987, p. 17. [10] P.H. Havstad, I.J. Garwin, W.R. Wade, A Ceramic Insert Uncooled Diesel Engine, SAE Paper, Detroit, MI, 1986, p. 18. [11] A.C. Alkidas, Performance and Emissions Achievements with an Uncooled Heavy-Duty Single-Cylinder Diesel Engine, SAE Paper, Detroit, MI, 1989, p. 19. [12] Y. Miyairi, T. Matsuhisa, T. Ozawa, H. Oikawa, N. Nakashima, Selective Heat Insulation of Combustion Chamber Walls for a DI Diesel Engine with Monolithic Ceramics, SAE Paper, Detroit, MI, 1989, p. 20. [13] T. Morel, S. Wahiduzzaman, E.F. Fort, Heat Transfer Experiments in an Insulated Diesel, SAE Paper, pp. 21.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study R. Udayakumar a, N.K. Miller Jothi b, Saurav Saboo a, Naseef Sadhik a a b
Department of Mechanical Engineering, Bits Pilani Dubai Campus, Dubai International Academic City, Dubai, UAE Department of Mechanical Engineering, Mekelle University, Ethiopia
a r t i c l e
i n f o
Article history: Received 13 October 2019 Received in revised form 8 November 2019 Accepted 26 December 2019 Available online xxxx Keywords: CI engines Rankine cycle Low heat rejection engines Ceramic coating Steam turbocharging
a b s t r a c t In an ordinary internal combustion engine only one third of the total heat liberated by the combustion of fuel is converted in to useful work. The exhaust gases leaving the engine are generally at a high temperature and hence they carry away a good amount energy. Substantial amount of energy is rejected via heat through the cooling system. An improvement in fuel economy could be seen, if the rejected energy to the coolant system could be used. LHR engines are the one in which the walls of the combustion chambers are coated with ceramic materials so that the heat loss to the coolant is very much reduced. It is thought that due to the adiabatic nature of the combustion chamber walls the energy available inside the cylinder for conversion in to useful work is more and this will improve the efficiency of the engine. But it is a wellknown fact that only a marginal increase in the thermal efficiency of the engine is noticed. The reduction of heat loss from the combustion chamber of diesel engines improves fuel efficiency only by 3 or 4 per cent. The major amount of energy goes with the exhaust gasses as the gasses leave the engine at a very high temperature. For more than a decade, many researchers have pursued the implementation of thermal barrier coatings (TBCs) in diesel engines to increase the combustion temperature and to increase the engine performance. In this work a novel method of recovering energy from the exhaust and to improve the overall efficiency of the engine is presented. The effect of thermal barrier coatings on diesel engine energy balance system is studied. Improving the performance of the engine by recovering heat from exhaust with Rankine cycle is investigated. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Recent Advances in Materials & Manufacturing Technologies.
1. Introduction A conventional internal combustion engine has the ability to convert only one-third of the heat energy from fuel into useful work, rest being lost to coolant and lost through exhaust. To improve the performance of the engine and to make use of most of the energy available through fuel, engineers are forced to research ways to recover these high amounts of energy lost. One successful way of recovering loss through exhaust is by installing a turbocharger in the engine. A turbocharger consists of a turbine and a compressor. The exhaust gases expand in the turbine, which in turn drives the air compressor. Air compressor boosts the intake pressure of the engine, hence improving its power output and performance. A typical turbocharger can improve the performance of the engine up to 15%. Most of
the modern-day automobiles make use of this technology as exhaust energy recovery system. The main drawback of this technology is that it uses pressure energy of the exhaust whereas maximum amount of energy in the exhaust is present in the form of heat. Consequently, engineers came up with steam turbocharging. It is similar to normal turbocharging except it uses bottoming Rankine cycle. Exhaust energy transfers its heat to water through a heat exchanger, which converts into steam and drives the turbine. This technology is much more efficient than the conventional turbocharger technology but has two major drawbacks, one being its intricate and complicated design, and the other being the weight increase of the car upon installation. Energy recovery from coolant is a much more difficult and inefficient task. Hence, engineers came up with the technology to minimize heat loss through coolant and thus low heat rejection
https://doi.org/10.1016/j.matpr.2019.12.338 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Recent Advances in Materials & Manufacturing Technologies.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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engines were introduced. The pioneers of this technology were able to improve the performance of the engine by 7%. By coupling Rankine cycle exhaust energy recovery system with low heat rejection engines, a very efficient engine can be designed with maximum use of the energy available to it. The main reason for this report is to discover the power balance at varied engine loads and speeds in a ceramic-covered diesel engine and scrutinize the performance change by coupling the engine with a Rankine cycle. Examinations were conducted in a six cylinder, turbocharged, inter-cooled diesel engine. 2. Low heat rejection engine concept The concept of low heat rejection engine is fairly old. Researchers and engine designers have long been aware that increasing the combustion temperature and reducing the heat losses through the combustion chamber walls will increase thermodynamic efficiency of the engine. The diesel engine with its combustion chamber walls insulated by ceramic coatings is referred to as Low Heat-Rejection (LHR) engine or semi adiabatic engine. The LHR engine has been developed basically to improve fuel economy by eliminating the cooling losses and converting part of the increased energy available in the exhaust gases into shaft work using the turbochargers. A good amount literature is available on the overall performance of the engine, durability of the coatings and operation of LHR engines with alternate fuels Morel et al., have discussed a new concept of the LHR engine and they have studied the performance of the engine with the turbochargers [1]. The authors [2,3] discussed about the LHR engines and they have concluded that the use of Thermal Barrier Coatings (TBCs) lead to multifuel capacity, better fuel efficiency, and higher power density due to higher chamber combustion temperature in diesel engines. The introduction and development of advanced ceramic materials and the coating techniques in the past few decades have made lot of progress in the research especially with respect to Diesel engines. In 1975, the U.S. companies like Cummins and TACOM have initiated an ‘‘adiabatic” program in engines and significant progress has been made in the field after that [4,5]. In addition, companies like Isuzu Motors [6,7], Ford Motor Company [8,9] have conducted various experimental work including the endurance tests with the LHR Engines. Most of them have stated that heat transfer is reduced by thermal insulation, but none have delivered such results in terms of engine performance or efficiency [4,5]. Two main problems associated to the development of the LHR engines are the strength and wear resistance of the various engine components at excessive temperatures. Generally, the traditional lubricants and metals neglect to perform at raised temperatures though, an alternative can be provided by using ceramic materials. These materials have given a significant push in further researching LHR in recent years. The different materials that are attempted are partially stabilized oxide of zirconium, (ZrO2); oxides of iron, aluminium, and chromium (Fe2O3, Al2O3, and Cr2O3); and carbides and nitrides of silicon (SiC and Si3N4). The various aspects of Low Heat Rejection Engines using different ceramic materials are presented in detail in the literature [10 –13]. 2.1. Constraints in ceramic coating The mismatch in the coefficient of thermal expansion is a severe constraint for proper adherence of the coating. This difficulty has been successfully overcome by introducing an intermediate expansivity-compensating layer between metal and ceramic. This intermediate layer (of thickness 0.15 mm) absorbs stresses between ceramic and metal produced due to thermal cycling.
When a plasma sprayed coating of thickness of 0.05 mm is given using partially stabilized zirconia (PSZ) on a metal with an intermediate layer of thickness 0.15 mm, the temperature drops from 1450 °C to 700 °C. Ceramic coating of thickness 0.15 mm to 1.0 mm given to the combustion chamber increases the operating temperature considerably. 2.2. Various types of coating techniques The following are the various coating techniques a. b. c. d. e. f.
Flame spraying Electric arc spraying Chemical vapor deposition and physical vapor deposition Detonation gun Jet kote Plasma Spraying
2.3. Plasma Spraying: Plasma spraying uses an electric arc maintained in a nozzle and an electrode as a heat source. This arc heats the stream of inert gases generally argon, hydrogen, nitrogen, or helium through a very high temperature more than 20,000 °C. This causes dissociation and ionization of the gas molecules. A large increase of gas volume occurs due to high temperature so that gas flow from the nozzle is at high speed (1000 m/s). The coating material is injected in powder form with the aid of a carrier gas Argon into this high energy plasma jet. This is the commonly used method in the engine applications. 2.4. Types of coating materials and characteristics There are different materials available for coating, among them the following are studied: a. Syalon (Si – Al – O – N): The name derives from the elements of Si – Al – O – N, and at its latest formulation, the mixture is stronger than steel, diamond hard, light as Al. It has exceptional resistance to wear and thermal shock. It retains its compressive and tensile strength at temperatures up to 1400 °C, while individual properties are not necessarily outstanding. b. Silicon Nitride (Si N): Silicon nitride is well known for its unique characteristics, such as, high strength at high temperatures, excellent wear resistance, very good thermal shock resistance and resistance to corrosion. Values in excess of 1000 MN/m2 for flexural strength are obtained and can be maintained to the temperature of about 1000 °C. Where ceramics operate to surpass metallic in strength properties, considerable degradation of strength occurs. The temperature strength degeneration is due to onset of slow crack growth. These properties should make Si N a material for heat engines and it has been called the ceramic of the decade in last ten years. c. Silicon Carbide: Silicon carbide is known for its exceptionally high oxidation resistance up to 1000–1200 °C. It is a strong candidate for structural ceramic applications such as in turbo-automotive parts. Silicon Carbide based ceramic materials include – hot pestered SiC, reaction sintered (or bonded) SiC, silicon carbide and silicon composites. Hot pestered carbide provides the highest strength avail-
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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able (550 MN/m2 at 1375 °C) over the other silicon carbide based materials. At a working temperature of 1300 °C, self-bonded silicon carbide is also a potentially viable material, although it does suffer from a short fall in properties above 1400 °C due to melting of free silicon which is available in the material. d. Hot Pressed Silicon Carbide Material (HPSN): HPSN is produced by either uniaxial or hot iso-static pressing of Silicon carbide powder with Alumina or Boron and Carbon to obtain a wide range of room temperature strength materials, which has the following properties. High temperature strength, creep fracture toughness, high fracture resistance coefficient and excellent thermal shock and corrosion resistance.
engine. Therefore, lowering or complete removal of this pumping loss seems to be the primary objective of this system. Their relationship can be shown as,
BMEP ¼ IMEP þ PMEP FMEP
where PMEP is the pumping mean effective pressure, IMEP is the indicated mean effective pressure, FMEP is the friction mean effective pressure, BMEP is the brake mean effective pressure, which is a standout amongst the most critical parameters of IC engine power performance. Fig. 1 depicts for the exhaust turbocharging system. From the figure, the relationship around PMEP, exhaust and intake pressure is given as,
PMEP ¼ P2 P3 Pcylinder port loss e. Reaction Bonded Silicon Nitride (RBSN): Reaction bonded silicon nitride possesses appreciable porosity, but they are cheap and easy to fabricate from silicon powder by compaction using cold pressing, flame spraying, slip-casting or plastic-binder molding techniques. It maintains its strength to temperature beyond 1400 °C, exhibits creep rate significantly below those of HPSN. f. Partially Stabilized Zirconia (PSZ):
ð1Þ
ð2Þ
If intake pressure of the IC engine is more than the exhaust pressure, pumping mean effective pressure will be positive. On the other hand, if the opposite situation is considered, a negative PMEP value will be obtained, and IC will need to dissipate some energy to overcome this [2]. This is more prevalent in exhaust turbocharged engines as exhaust pressure is on the high side and on some instances, energy lost through pumping is more than energy recovered. The Fig. 2 shows the PV diagram for the turbocharged engine. These engines generally reduce the PMEP so that the net power output can be increased.
Toughened partially stabilized zirconia (PSZ) ceramics possess several good properties so that it is used in a variety of advanced engine components, in particular for adiabatic engine systems. Magnesia-partially stabilized Zirconia (Mg-PSZ) is one of the toughest ceramics possessing excellent insulating, high strength, good thermal shock and wear resistance properties. In addition, PSZ has a thermal expansion and elastic modulus similar to iron and steel. As a result of the combination of these thermal and mechanical properties it is suitable for application such as cylinder liners, valve guide, valve seats, piston caps, hot plates and tapped inserts. 3. Exhaust turbocharging Exhaust turbocharging uses exhaust gases to boost the engine intake pressure. In this system, exhaust gases from cylinders drive the turbine, which in turn drives the air compressor. Therefore, exhaust turbocharging is a kind of immediate system to recover energy losses from exhaust and increase performance. At present, it is the most widely used technology and can be found in all the cars that use exhaust energy recovery system. But it is a very inefficient of exhaust energy recovery system with its drawbacks mentioned as follows
Fig. 1. The schematic diagram of the exhaust turbocharging system.
As the flue gas expands in turbine exhaust back pressure is increased and therefore increase the losses; At lower RPMs this system is inefficient as exhaust pressure is low and at higher RPMs exhaust pressure is too high that some amount of energy has to be discarded through the wastegate; As a part of exhaust energy recovery system, the system in itself is inefficient as it uses pressure energy of the exhaust whereas most of the energy is available in the form of heat; Matching process of the turbocharger and internal combustion engine is a hard process as internal combustion engine exhaust parameters fluctuate frequently. 4. Pumping loss of the exhaust turbocharged engines As reported before, the greatest drawback of an exhaust turbocharging system in an IC engine is the high pumping losses associated with it, which significantly influences efficiency of the IC
Fig. 2. P-V diagram of an in-cylinder cycle for exhaust turbocharging engine.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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5. IC engine steam turbocharging The drawbacks of the exhaust turbocharging are discussed in the Section 3. Most of the problems presented can be overcome by adopting the new approach which is called steam turbocharging. This is based on the Rankine steam cycle. It will be an indirect method in which the heat from the exhaust gasses will be transferred to a steam generator. The steam generated in it will be allowed to expand through a steam turbine which will be used for supercharging the engine. The schematic diagram of steam turbocharging is shown in the Fig. 3. It consists of a heat exchanger which extracts heat from the exhaust gases and is transferred to the water in the steam generator and steam is produced. In addition to a normal turbocharged engine, it contains a motor where the excess energy recovered can be stored and used for different purposes. As mentioned before the cycle followed is Rankine Cycle with a tank, pump and a heat exchanger. The features of the various modes of operation are explained below. Starting, low speed and low load mode: When the IC engine is started and running at low speed or running at low load the heat energy available in the exhaust gasses may not be sufficient to produce enough steam to run the steam turbine. Hence during such periods, the air compressor will be driven by the electric motor in the system. High Speed and High load mode: During high load and highspeed conditions of the engine, the heat energy available in the exhaust gasses will be very high and by recovering the energy it is possible to run the steam turbine. Also, there will be additional power that will be available from the steam turbine over and above which is required to run the air compressor and this excess power can be then utilized to run the motor which will act as an alternator. The electric power thus produced can be stored in the batteries. This power will be utilized to run the compressor during the low speed and low load conditions of the engine. Basic analyses of the characteristics of the steam turbocharging are as follows Inter connecting the motor with the output shaft of the engine has many advantages. It ensures that turbocharging system will have better transient response for the different operating conditions. The turbo lag can be very much reduced. The efficiency of
the energy recovery system will also be increased very much. Even at starting and low speed operating conditions the engine will have good amount of power boost. In a conventional exhaust gas turbocharging system, the exhaust gas parameters fluctuate very much with respect to the various operating conditions of the engine. The system will not be able work in the optimum conditions. On the other hand, the operating parameters of the proposed steam turbocharging system such as the steam pressure& temperature, the flow rate etc. can be accurately controlled by the controls incorporated in the engine system. Hence the proposed system will operate in near optimum conditions at all the time. In steam turbocharging the bottom steam cycle is connected to the working cycle of the engine through transfer of heat instead of transmission through pressure. Hence it does not put any restriction on the exhaust conditions of the engine. The exhaust pressure of steam turbocharging engine can be largely reduced compared to exhaust driven turbocharging system. This may avoid exhaust blow down and increase the engine power output. The pumping work of steam turbocharged engine during the intake and exhaust process may also change from negative to positive.
6. Engine analysis A low heat rejection engine is chosen for the current research which is 4 stroke, 6 cylinder, 6-liter turbocharged engine. Its specifications are given in Table 1. The energy distribution of normal IC engine and ceramic coated IC low heat rejection engine tests are shown in Figs. 4–6. It speaks to the variety of the power offset at three different loads of low, medium and high load. Up to 40% load may be considered as low load and 40–70% may be considered as medium load and above 70% may be considered as high load operations. At various rpms and loads, the diminishment in heat dismissal for the most part
Table 1 Specifications of the engine. Engine type Maximum Power Bore Stroke Compression Ratio Injection Timing (°CA) Displacement volume
Ford 6.0, T/CI, DI, 4 stroke and 6 cylinder 136 kW @ 2400 rpm 104.77 mm 114.9 mm 16.5:1 27° BTDC 5.947 L
Fig. 3. Schematic diagram of steam turbo charging system.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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Fig. 4. Energy distribution in low load condition.
Fig. 5. Energy distribution in medium load conditions.
Fig. 6. Energy distribution in high load conditions.
brought about an increment in exhaust energy. Results are shown as follows:
7. Results and discussion To recover the energy available in the exhaust by Rankine cycle, energy from the exhaust gases must first be transferred to water through heat exchanger. For designing the heat exchanger and to determine the energy acquired by water we first find the exhaust parameters. With the help of the brake specific fuel consumption (kg/kw-h), the mass flow rate of fuel is calculated and from the air-fuel ratio used by the engine the air flow rate to the engine is
calculated. The mass flow rate of exhaust gases is calculated by mass flow rate of the fuel plus mass flow rate of the air at a particular speed of the engine. These values are then used to find the mass flow rate of steam that is produced in the heat exchanger and entering the turbine. Heat transfer between exhaust and water takes place in a shell and tube heat exchanger. By following the standard procedure for designing the heat exchanger the heat transfer area is calculated as 0.401 m2 using NTU method. Number of tubes are found to be about 28 with outside diameter of tube as 0.012 m and length of the tube as 0.38 m. Number of baffles were taken as 15 with baffle spacing was calculated as 0.0271 m. Number of passes were taken as 1 with tube clearance as 0.096 m. The efficiency of turbine
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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Table 2 Output of the software at the engine speed of 1800 rpm. Steam inlet condition Parameter Pressure Temperature Phase Steam flow rate Sp.Enthalpy Sp.Entropy Energy Flow
Unit 39.48 bar 400 °C Gas 226.7 kg/hr 3212 kJ/kg 6.7574 kJ/kgK 738539 kJ/hr
Power output
Steam outlet condition
(KW) 18.6 18.6 18.6 18.6 18.6 18.6 18.6
Parameter Pressure Temperature Phase Steam flow rate Sp.Enthalpy Sp.Entropy Energy Flow
and generator is 80% and 95% respectively. With these inlet values of steam, power that could be produced in the steam turbine is calculated using the steam turbine software by EERE advanced manufacturing office. The following is the output of the software at the engine speed of 1800 rpm which is given in Table 2 and similarly for other speeds of 2000 rpm; 2200 rpm and 2400 rpm the values are obtained from the software. 7.1. Power generation and efficiency The Fig. 7 shows generated power with respect to the different rpm. We can deduce from this graph that at higher rpms we got
Unit 4.9 bar 198.5 °C Gas 226.7 kg/hr 2847 kJ/kg 6.9584 kJ/kgK 633033 kJ/hr
more power from exhaust than at lower rpms as exhaust energy is more at higher rpms. The air compressor is driven by the generated power. Maximum power attained is calculated to be as high as 36.1 kW for the engine and the exhaust heat exchanger combination. At higher rpms excess energy left, after utilizing the rest to drive the air compressor, can be stored and used to drive air compressor at lower rpms when energy available is not high enough to drive the air compressor, as well as can be used for other miscellaneous things. Therefore, there is no turbo lag and a constant intake pressure boost is supplied to air entering the cylinder. The Fig. 8 depicts the variation of efficiency with respect to the different rpm. Efficiency is the ratio of power obtained from turbine to the brake power available to the engine. We can conclude from this graph that efficiency is higher at higher rpm and goes up as high as 26.5% whereas in normal turbocharged engines maximum attainable efficiency could reach as high as 15%. The rate of increase in efficiency shows that this system is better at high rpm conditions than at lower rpm conditions.
8. Conclusion This study presents an idea of steam turbocharging which helps in increasing the overall efficiency and the inlet pressure of the IC engine. Compared with other techniques such as exhaust turbocharging, it provides many advantages and can successfully enhance the utilization of the IC engines. Based on the research the following conclusions are drawn. Fig. 7. Generated power in the steam turbine at various engine speeds.
Fig. 8. Efficiency versus engine speed.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338
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Because exhaust turbocharging system reuses IC engine exhaust energy through a system after the exhaust manifold, its exhibitions are just dictated by exhaust parameters, particularly the exhaust pressure. Notwithstanding, steam turbocharging systems recoups IC engine exhaust energy focused around heat transfer and steam power cycle. What’s more important is its performances could be enhanced by selecting bottom cycle system parameters, for example, steam pressure and stream rate. Besides, this engineering could be straightforwardly connected on IC engine without altering its principle structure. When the steam turbocharging system is connected to IC engine, both the power and warming up of IC engine are improved compared to exhaust turbocharging engine. At the pace of 2400 revolutions/min, power available from turbine was calculated as 36.1 kW, which is 26.5% of its brake power. This clearly shows that the steam turbo charging has great energy saving potential. Since exhaust energy is very high in low heat rejection engines, turbocharging using Rankine cycle finds its best use in recovering the heat from exhaust. This technology will surely be widely used in the field of automobiles in the coming future. From this research, it is safe to conclude that this technology has a lot of importance in the upcoming years. With efficiencies more than double of the exhaust energy recovery systems that are used today, this technology finds a large scope in the near future. Also, it is the only technology that reduces energy losses from both exhaust and coolant thus, maximizing the use of energy available. The only shortcoming it faces today is its intricate and complex design as automobile manufacturers find it difficult to design it in their products. Also, it adds a considerable amount of weight to the car and increases the price of production thus making the manufacturers reluctant in using this technology in the present day. However, as fuel will get scarcer, its prices will steep, turning pro-
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duction cost less important than the running cost of the automobile, making this technology indispensable for the future. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] T. Morel, S. Wahiduzzaman, E.F. Fort, D.R. Tree, D.P. DeWitt, K.G. Kreider, Heat Transfer in a Cooled and an Insulated Diesel Engine, SAE Paper, Detroit, MI, 1989, p. 9. [2] P. Ramaswamy, S. Seetharamu, K.B.R. Varma, N. Raman, K.J. Rao, thermomechanical fatigue characterization of zirconia (8% Y2O3-ZrO2) and mullite thermal barrier coatings on diesel engine components: effect of coatings on engine performance, Proc. Instn. Mech Eng. 214 (729–742) (2000) 10. [3] D. Zhu, R.A. Miller, Thermal Barrier Coatings for Advanced Gas Turbine and Diesel Engines, NASA/TM, 1999, p. 11. [4] W. Bryzik, R. Kamo, TACOM/Cummins Adiabatic Engine Program, SAE Paper, Detroit, MI, 1983, p. 12. [5] P. Badgley, R. Kamo, W. Bryzik, E. Schwarz, NATO Durability Test of an Adiabatic Truck Engine, SAE Paper, Detroit, MI, 1990, p. 13. [6] M. Woods, W. Bryzik, E. Schwarz, 100 Hour Endurance Testing of a High Output Adiabatic Diesel Engine, SAE Paper, Detroit, MI, 1994, p. 14. [7] H. Kawamura, H. Matsuoka, Low Heat Rejection Engine with Thermose Structure, SAE Paper, Detroit, MI, 1995, p. 15. [8] H. Kawamura, Development Status of Isuzu Ceramic Engine, SAE Paper, Detroit, MI, 1988, p. 16. [9] W.R. Wade, P.H. Havstad, V.D. Rao, M.G. Aimone, C.M. Jones, A Structural Ceramic Diesel Engine - The Critical Elements, SAE Paper, Detroit, MI, 1987, p. 17. [10] P.H. Havstad, I.J. Garwin, W.R. Wade, A Ceramic Insert Uncooled Diesel Engine, SAE Paper, Detroit, MI, 1986, p. 18. [11] A.C. Alkidas, Performance and Emissions Achievements with an Uncooled Heavy-Duty Single-Cylinder Diesel Engine, SAE Paper, Detroit, MI, 1989, p. 19. [12] Y. Miyairi, T. Matsuhisa, T. Ozawa, H. Oikawa, N. Nakashima, Selective Heat Insulation of Combustion Chamber Walls for a DI Diesel Engine with Monolithic Ceramics, SAE Paper, Detroit, MI, 1989, p. 20. [13] T. Morel, S. Wahiduzzaman, E.F. Fort, Heat Transfer Experiments in an Insulated Diesel, SAE Paper, pp. 21.
Please cite this article as: R. Udayakumar, N. K. Miller Jothi, S. Saboo et al., Turbocharging in ceramic coated engines using Rankine cycle for automotive use – An inceptive study, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.338