Browse Topic: Adiabatic engines

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Computerized Experimental Investigation on Performance & Exhaust Emission of Twin Cylinder Adiabatic Diesel Engine Coated with YSZ2019-28-254811/21/2019
The fuel consumption and performance of the Internal Combustion (IC) engine is improved by adopting concepts of an adiabatic engine. An experimental investigation for different load conditions is carried out on a water-cooled, constant-speed, twin-cylinder diesel engine. This research is intended to emphasize energy balance and emission characteristic for standard uncoated base engine and adiabatic engine. The inner walls of diesel engine combustion chamber are thermally insulated by a top coat of Metco 204NS yttria-stabilized zirconia (Y2O3ZrO2) powder (YSZ) of a thickness of 350 mm using plasma spray coating technology. The same combustion chamber is also coated with thermal barrier coating (TBC) bond coats of AMDRY 962 Nickle chromium aluminum yttria of thickness of 150 mm. The NiCrAlY powder specially designed to produce coating’s resistance to hot corrosion. The combination of this ceramic material produces excellent high-temperature thermal barrier coating (TBC) resistant to thermal cycling stresses and strains. The engine valves, engine heads, and engine pistons were thermal barrier ceramic coated and computerized experimental results were compared to the base engine. Experimental results justified TBC engine to give a better diesel engine combustion cycle analysis. The main objective of this study is to increase power and torque parameters resulting in a decrease in fuel consumption. Furthermore, the exhaust emission parameter was found to be decreased. The noise level of the adiabatic engine was found satisfactorily.
Gosai, Dr. Dipakkumar C., Gillawat, Anil Kumar
Study of Effect of Coating of Piston on the Performance of a Diesel Engine2014-01-10214/1/2014
Insulation of pistons in engines is aimed at reducing the heat losses and thus increasing the indicated efficiency. Thermal barrier coatings (TBCs) were used to simulate adiabatic engines with the intention not only for reduced in-cylinder heat rejection and thermal fatigue protection of underlying metallic surfaces, but also for possible reduction of engine emissions. The application of TBCs reduces the heat transfer to the engine cooling jacket through the combustion chamber surfaces (which include the cylinder head, liner, and piston crown) and piston rings. The insulation of the combustion chamber with this coating, which is ceramic based, influences the combustion process and hence the performance and exhaust emissions characteristics of the engines. In the scenario of fast rising oil prices, insulation technologies are gaining importance as they help in saving fuel. A plasma sprayed thermal barrier coating was deposited on top of a piston for a Diesel engine and its effect on the engine performance is studied. It is found to increase thermal and mechanical efficiency.
Rupangudi, Suresh Kumar, Ramesh, C.S., Veerabhadhrappa, Kavadiki, V, Ram Rohit
Advances in surface engineering13MEIP12_0212/1/2013
Newer materials with improved properties can enhance the properties of the working surfaces of cylinder components for the demands of increased temperatures, pressures, and corrosive atmospheres and still satisfy performance and life requirements. By all accounts, the internal-combustion engine will continue to play a major role as the prime mover for automotive vehicles for decades to come. It has faced a lot of challenges in the past, but it is also true that at every challenge, the industry comes up with an adequate response to meet that challenge in part or in full. Higher specific output, tighter emission norms, CO2 reduction through better fuel economy, longer life, and affordability will remain as persistent demands from the engine designer in the foreseeable future. The order of priority may change, influenced by factors such as fuel and oil prices, state of infrastructure, customer preferences, legislation, resale value, etc.
Mahadevan, R.
Concept of “Temperature Swing Heat Insulation” in Combustion Chamber Walls, and Appropriate Thermo-Physical Properties for Heat Insulation Coat2013-01-02744/8/2013
The aim of this work is to investigate the possibility of heat insulation by “Temperature Swing”, that is temperature fluctuation, on combustion chamber walls coated with low-heat-conductivity and low-heat-capacity materials. Adiabatic engines studied in the 1980s, such as ceramic coated engines, caused constantly high temperature on combustion wall surface during the whole cycle including the intake stroke, even if it employed ceramic thermal barrier coating methods. This resulted in increase in NOx and Soot, decrease in volumetric efficiency and combustion efficiency, and facilitated the occurrence of engine knock. On the other hand, “Temperature Swing” coat on the combustion chamber walls leads to a large change in surface temperature. In this case, the surface temperature with this insulation coat follows the transient gas temperature, which decreases heat loss with the prevention of intake air heating, and also which is expected to prevent NOx and Soot from increasing. In our calculations, the increase of the surface temperature fluctuation, “Temperature Swing” results from the coat of lower heat conductivity and lower heat capacity. Particularly in Gasoline engines, the coat with the appropriate thickness can reduce the heat flux from the wall to the working gas during intake stroke and can avoid engine knock. Based on our calculations, it is clarified that both the prevention of intake air heating and the low heat rejection were successfully possible with the material of appropriate thermo-physical properties. In addition to the calculations, a preliminary test-piece experiment was executed. It was demonstrated that the surface temperature of a porous coat, that is a candidate of “Temperature Swing” coat, immediately follows the transient gas temperature, and also the proposed insulation coat can exactly reduce the heat flux in the single-cylinder engine.
Kosaka, Hidemasa, Wakisaka, Yoshifumi, Nomura, Yoshihiro, Hotta, Yoshihiro, Koike, Makoto, Nakakita, Kiyomi, Kawaguchi, Akio
Investigation on the Fuel and Engine Parameters that Affect the Half Mass Fraction Burned (CA50) Optimum Crank Angle2012-36-049810/2/2012
In-cylinder pressure measurements and indicating diagrams have proven to be a valuable research tool for the analysis of combustion in spark-ignition or compression-ignition engines. With the use of thermodynamic models, the rate of heat release and mass fraction burned curves are calculated, and from the latter the CA50 parameter (crank angle fifty), which is the angle in which 50% of the total fuel has been burned. The empirical process of obtaining the optimum start of combustion typically leads to a value of CA50 from 8° to 10° after top dead center. This paper attempts to numerically investigate which properties have an influence on this optimum CA50. A simple thermodynamic model was implemented which used the Wiebe function for the rate heat release. The CA50 was then evaluated for combustion duration in the base configuration and in a theoretical adiabatic engine. Results showed that the CA50 is mildly sensitive to combustion duration and highly sensitive to the wall heat transfer coefficient, reaching very low values (still always located after top dead center). These lower values provided higher work output in the model. The main conclusion is that the optimal combustion timing of 8° to 10° is due to a compromise between power, wall heat transfer and exhaust gas energy, which prevents lower values.
de O. Carvalho, Leonardo, de Melo, Tadeu C. Cordeiro, de Azevedo Cruz Neto, Rubelmar M.
High Efficiency Internal Combustion Stirling Engine Development2011-01-04104/12/2011
A unique engine, based on the regenerative principle, is being developed with the goal of achieving high brake efficiency over a wide power range. It can be characterized as an internal combustion Stirling engine (ICSE). The engine is a split-cycle configuration with a regenerator between the intake/compression cylinder and the power/exhaust cylinder. The regenerator acts as a counter-flow heat exchanger. During exhaust, the hot gases are cooled by the regenerator. The regenerator stores this heat. On the next cycle, compressed gases flow in the opposite direction and are heated by the regenerator. The gases coming from the regenerator into the power cylinder are very hot (~900°C), which provides the necessary gas temperature for auto-ignition of diesel and other fuels. A simplified Air Cycle analysis of the ICS engine is presented to validate the concept thermodynamics and to show the inherent difference between the ICS and conventional internal combustion engine (ICE) indicated efficiency. The ICE engine indicated efficiency increases with increasing compression ratio and is insensitive to peak temperatures, whereas in the ICS engine indicated efficiency increases with decreasing compression ratio and increasing peak temperature. This engine concept is a candidate for application of adiabatic engine technology which has been explored for many years. With materials that can withstand high temperatures, brake efficiencies of 60-70% are possible. Low heat transfer is important to the proper operation of the engine. A multi-step cycle computer indicated thermodynamic and fluid flow model of the ICS engine of increasing detail was used during the engine development. Finally, detailed perturbation studies were conducted to fully understand the ICS design sensitivities. An engine friction model was added to the computer model to be able to compare estimates of ICSE BSFC and BMEP with ICE engines. Important ICS engine innovations include elimination of throttling losses, low friction due to low compression ratio, and very high air cycle efficiencies (~80%) combined with low compression ratio. The engine is designed for the highest possible efficiencies. In addition to these advantages, the engine has nearly constant pressure combustion, which should help reduce NOx formation. The major findings were: the ICS engine is more efficient than either gasoline or diesel engines over the entire operating range especially at part power. At wide open throttle, an ICS engine is more efficient than either a gasoline or a diesel engine. This advantage increases at part power. On the negative side, the ICS engine has inherent low power density (volumetric efficiency) because of low compression ratio, late air intake and late combustion. A prototype engine and a modest engine test dynamometer and instrumentation are nearing completion to demonstrate the P&B Enterprises, Inc. (PBEI), ICSE concept. The prototype is a retrofitted two-cylinder diesel engine. The prototype uses the existing engine block, and the crankshaft and camshaft fit into existing spaces in the block. Anticipated problems to be addressed with the prototype engine are starting, combustion characteristics, regenerator temperature control and high turbocharging ratios to achieve reasonable power density.
Patton, Richard, Bennett, George
Experimental Study on Thermal Barrier Coated Diesel Engine Performance with Blends of Diesel and Palm Biodiesel2010-01-15195/5/2010
Energy conservation and efficiency have been the quest of engineers concerned with internal combustion engine. Theoretically, if the heat rejected could be reduced, then the thermal efficiency would be improved, at least up to the limit set by the second law of thermodynamics. Low Heat Rejection engines aim to do this by reducing the heat lost to the coolant. For current work a ceramic coated twin cylinder water-cooled diesel engine using blends of diesel and palm biodiesel as the fuel was evaluated for its performance and exhaust emissions. In recent years, Considerable efforts were made to develop and introduce alternative renewable fuel, to replace conventional petroleum-base fuels. Here, the diesel engine was insulated by Partially Stabilized Zirconia (PSZ) as ceramic material attaining an adiabatic condition. The cycle average gas temperature and metal surface temperature are higher in adiabatic engine. For the present study the biodiesel was prepared in laboratory from non-edible vegetable oil (Palm oil) by transesterification process with methanol, where potassium hydroxide (KOH) was used as a catalyst. An experimental investigation of the performance of a ceramic coated engine was carried out with palm bio-diesels and its blends, the results were compared to the experiment done with the conventional petroleum diesel. Multi cylinder vertical water cooled self-governed diesel engine, piston, top surface of cylinder head and liners were fully coated with Partially Stabilized Zirconia (PSZ). Experimental test set-up was developed in laboratory. The stationary diesel engine was run in laboratory at a medium speed, variable load condition experienced in most urban driving conditions and various measurements like fuel flow, exhaust temperature, exhaust emission measurement and exhaust smoke test were carried out. The results indicate improved fuel economy and reduced pollution levels for the Thermal Barrier Coated (TBC) engine. The fuel properties of biodiesel such as kinematic viscosity, calorific value, flash point, carbon residue and specific gravity were found. Results indicated that Bio-diesels had lower brake thermal efficiency mainly due to its high viscosity compared to diesel. For biodiesel fuel, the exhaust gas temperature increased with increase in power and amount of biodiesel. However, during performance test it showed reasonable efficiencies, lower smoke, SO2, PM (particulate matter) and CO with some increase in emission of oxides of nitrogen. Biodiesel also increased efficiency in reducing particulate emissions. Regulated emissions and performance data were generated, and a detailed emission was performed. Fuel properties were close to the standard limit for diesel fuel. The use of palm biodiesel resulted in lower emissions of unburned hydrocarbons, carbon monoxide, and particulate matter, with some increase in emissions of oxides of nitrogen.
Modi, A. J., Gosai, D. C.
Numerical Modeling of Charge Stratification for the Combustion Control of HCCI Engines2005-01-372210/24/2005
Numerical modeling is used to estimate the realizable potential of combustion control and burn duration extension in homogeneous charge compression ignition (HCCI) engines using in-cylinder charge stratification. Parametric analyses of several fuels using a range of operating conditions illustrate the potential physical variables have on ignition timing and burn duration. The detailed stratification model utilizes a one-dimensional CFD gas dynamics representation of radial gas motion in an engine cylinder with time-varying chamber volume and detailed combustion chemistry of n-pentane fuel. This approach provides the ability to incorporate the effects of in-cylinder temperature and species concentration non-uniformities while remaining sufficiently tractable to include a detailed kinetic model of combustion chemistry. A parametric set of conditions was studied to determine the effect of stratified temperature, equivalence ratio, and EGR on the ignition timing and burn duration of a representative HCCI engine. The assumption of adiabatic engine operation was made to assess the potential of combustion control mechanisms separate from heat transfer effects. The results demonstrate that moderate and potentially achievable amounts of in-cylinder charge stratification result in extended heat release durations relative to homogeneous conditions. The use of combined temperature, equivalence ratio, and EGR variation in a conceptionally achievable configuration is shown to provide the largest benefit. A series of path forward research directions are also discussed.
Grenda, Jeffrey M.
Development of an Adiabatic Engine Installed Energy Recover Turbines and Converters of CNG Fuel2003-01-22656/23/2003
In order to improve the fuel consumption and control exhaust emissions in a heat insulation engine, fuels reformed CH4 by CO2 and steam were used. Porous metal plate coated Li2ZrO3 was used to make CO2 separate from the exhaust gas of the engine. CH4 and CO2 gas are supplied to the catalytic converter and reformed CO and H2gas increased to 30% on kinetic energy are supplied to the engine as well as gas and steam turbine is installed to recover the exhaust gas energy. As the result the thermal efficiency of the engine systems will be improved to about 57.5% compared with 42% of conventional diesel engine.
Kawamura, Hideo, Akama, Mitsuru
The Hydrocycle Rocket Free-Piston Instant-Conversion Adiabatic Engine and One-Range, Infinitely Variable Hydrostatic Transmission System9600892/1/1996
The ideal internal-combustion crankshaft engine would burn all the fuel near top center without detonation, then expand the whole charge until exhaust Both events are impossible with current piston engines. The Hydrocycle Rocket Piston Engine concept employs a free piston in the head of a two-stroke-cycle engine. Combustion between the crank piston and the free piston allows direct conversion of combustion fluid expansion to hydrostatic fluid flow and accumulator gas compression with perfect timing and minimum thermal and mechanical losses. An infinitely variable, radial hydrostatic motor gives the driver smooth, gas-cushioned acceleration and stepless performance. Maximum economy is attained since the driver is forced to run the engine at optimum minimum speed to match road load oadin all traffic conditions.
Christenson, Howard W.
Recent Development of Tribological Coatings for High Temperature Engines9509792/1/1995
Lubrication of advanced high temperature engines has been one of the greatest obstacles in the development of the Adiabatic engine. Liquid lubricants which gave lubricating properties as well as heat removal function can no longer carry out this duty when piston ring top ring reversal temperatures approach 540°C. Solid lubricants offer some hope. Since solid lubricants cannot perform the heat removal function, its coefficient of friction must be very low, at least <0.10, in order to prevent heat build up and subsequent destruction to the piston rings and cylinder liners. The Hybrid Piston concept developed in the U.S. Army Advanced Tribology program offers some hope, since the top solid lubricant ring slides over the bottom hydrodynamic lubricant film section during each stroke. This paper presents the progress made with the solid lubricant top ring in the Hybrid Piston. Four materials have shown promise in the laboratory to fullfil its mission. The characteristic pairs are: Detonation Gun (D-Gun) sprayed and densified chrome oxide versus densified plasma sprayed chrome oxide. Densified plasma sprayed chrome oxide versus densified plasma sprayed Tribaloy T-800. Densified plasma sprayed iron oxide versus densified plasma sprayed Tribaloy T-800. Densified Slurry iron oxide versus densified hardened M-2 steel. Densification or thermal sealing the plasma spray layer, a process developed on the project, improves the coating's tribological properties. These coating materials are awaiting to be tested in the single cylinder engine.
Kamo, Lloyd, Kleyman, Ardy, Bryzik, Walter, Schwarz, Ernest
Development of Model 6105 Adiabatic Engine9309843/1/1993
A commercially available water-cooled engine Model 6105 was modified into an adiabatic engine without independent cooling water system. The modified engine was built to have monolithic ceramic composite pistons and zerconia coatings on the firedeck of cylinder heads, the disk surface of inlet and exhaust valves, and the upper part of cylinder liners. Its supercharging system and fuel injection system were adjusted. The test results showed that such modifiation could lead to an improvement up to 5.5% of fuel consumption over the baseline engine. Having undergone a 400-hour endurance stand test, the engine was installed in a bus, and has been completed a on-board trial covering more than 10000km.
Nanlin, Zhang, Shengyuan, Zhong, Jingtu, Feng, Jinwen, Cai, Qinan, Pu, Yuan, Fan
Design Optimization of the Piston Compounded Adiabatic Diesel Engine Through Computer Simulation9309863/1/1993
This paper describes the concept and a practical implementation of piston-compounding. First, a detailed computer simulation of the piston-compounded engine is used to shed light into the thermodynamic events associated with the operation of this engine, and to predict the performance and fuel economy of the entire system. Starting from a baseline design, the simulation is used to investigate changes in system performance as critical parameters are varied. The latter include auxiliary cylinder and interconnecting manifold volumes for a given main cylinder volume, auxiliary cylinder valve timings in relation to main cylinder timings, and degree of heat loss to the coolant. Optimum designs for either highest power density or highest thermal efficiency (54%) are thus recommended. It is concluded that a piston-compounded adiabatic engine concept is a promising future powerplant.
Assanis, Dennis N., Bell, James A. E.
Heat Rejection from High Output Adiabatic Diesel Engine9205412/1/1992
Woods, Melvin, Bryzik, Walter, Schwarz, Ernest
The Influence of Soot Deposits on Combustion Chamber Walls on Heat Losses in Diesel Engines9102972/1/1991
A modified equation for the heat transfer coefficient has been established, because the original equation proposed by the author in 1967 provides at low load and motored operation to low results. The reason for this descrepancy seems to be a steady state soot layer, the thickness of which increases with increasing load, where as it does not exist in a motored engine. All equations for the heat transfer coefficient known either to, do not represent the real heat transfer coefficient accuring at the soot layer surface, but include the thermal conductivity resistance of the soot layer. The real heat transfer coefficient is more than two times higher than assumed up to now. These results also show the adiabatic engine in a totally new light.
Woschni, Gerhard, Huber, Karl
Nato Durability Test of an Adiabatic Truck Engine9006212/1/1990
A previous paper (1)* described the performance improvements which can be obtained by using an “adiabatic” (uncooled) engine for military trucks. The fuel economy improved 16% to 37% (depending upon the duty cycle) and was documented by dynamometer testing and vehicle testing and affirmed by vehicle simulation. The purpose of this paper is to document a NATO cycle 400 hour durability test which was performed on the same model adiabatic engine. The test results showed that the engine has excellent durability, low lubricating oil consumption and minimal deposits.
Badgley, Patrick, Kamo, Roy, Bryzik, Walter, Schwarz, Ernest
Study of Construction and Tribology in Heat Insulated Ceramic Engine9006242/1/1990
An adiabatic engine was constructed with the monolithic type ceramic material. A highly durable and superior heat insulating engine could be completed, through detailed study of the design, evaluating the ceramics of which reliability is inferior in strength, going back to the microstructure and improving it to the utilizable level as the engine parts. I started studying the combustion in a bid to accomplish improvement of the fuel consumption rate, realization of multi-fuel engine and pollution-lowering, but I found out that recovering of the ignition delay shortening can be coped with by high pressure injection, fuel nature modification and so forth. In future, I have to pursue my studies in connection with reduction of emission of exhaust gas like the NOx and recovery of energy from the exhaust gas, and the similar subjects.
Kawamura, Hideo
A Low NOx Emission and Effective Exhaust Energy Recovery Adiabatic Engine System9006222/1/1990
Much effort has been made to develop ceramic engine. Power turbines are usually used to recover excessive exhaust energy. The unsatisfactory problems are their high initial cost, complex structure and poor acceleration response. In the new system suggested here, the excessive exhaust energy is transferred to crank work through the pre-expanding process by higher pressurized intaked air during the intake stroke, thus the cycle temperature is lowered. Both thermodynamic analysis and performance simulation of this system were made, results showed that the fuel consumption of the new system could achieve the lever of power turbine's. A test bed of turbocharged engine was used to study the performance of the new system. Because of its simple structure, high acceleration response and low cycle temperature which leads to low NOx emission, this system is thought to be a competitive candidate for adiabatic engine sets.
Wei, Xu Zhi, Zhong, Gu Hong
Laboratory Development and Engine Performance of New High-Temperature Diesel Engine Lubricants8901452/1/1989
New high-temperature lubricants are being developed for future U.S. Army low heat rejection diesel engines. Compared to the best previous low heat rejection diesel engine lubricant, the first new lubricant developed was shown to (1) be less volatile, (2) have 55°C (100°F) greater oxidative stability, and (3) increase high-temperature single cylinder engine life more than five times. The new lubricant successfully completed a 400 hr multicylinder engine test in a U.S. Army 5-ton truck adiabatic engine. Lubricant property changes, engine wear, deposits and oil consumption were all very low. Two additional new liquid lubricants were developed for operation at higher engine temperatures than those of the 5-ton truck. Engine tests of these new lubricants will be conducted in the near future. Hybrid liquid/solid lubricants were formulated and evaluated for potential reduction of wear and friction at high temperature, with mixed results.
Sutor, Paul, Bryzik, Walter
Tribological Aspects of Cylinder Kit Systems in Adiabatic Engines8800182/1/1988
The successful operation of a piston-ring pack-liner-lubricant system in an adiabatic engine will not only require the development of ring face materials, liner surface materials and lubricants, but also the implementation of models which can define the environment in which the materials and lubricants are expected to operate. The purpose of this paper is to identify work which has been previously conducted in this area and to outline the elements of a new model which has been developed to integrate the effect of combustion pressure, ring movement and oil characteristics along with those variations in contact loading caused by cylinder liner and ring distortions due to mechanical and thermal loads. In addition, an advanced bench wear tester is described. This device was developed to permit the determination of wear characteristics of materials under actual operating conditions.
Brombolich, Lawrence J., McCormick, Harold E.
Engine Component Design Methodology for Ceramic and Ceramic-Matrix Composite Materials8801932/1/1988
In the past two years, significant progress has been made in the application of ceramic-matrix composite materials to low heat rejection engine components. However, past R&D programs have identified a number of critical areas which require additional effort including: Life Prediction Methodology, Non-Destructive Testing, Design Methods, Data Base Development, and Verification of Design Rules. This paper discusses an integrated design methodology for addressing these research needs. The paper concludes with a specific example of a ceramic fiber-reinforced metal matrix composite piston which has been designed for application to advanced adiabatic engines.
Glance, Paul C., Bryzik, Walter, Mahishi, Jayant, Spehar, Jeff
Development Status of Isuzu Ceramic Engine8800112/1/1988
Ceramics show high degree of heat resistance. But an attempt to build an adiabatic engine using ceramic materials should be carried out by full evaluation of characteristics of each ceramic material. The strength of ceramic parts are dependent on both their manufacturing processes and the mechanical and thermal stresses to which the parts are subjected. Full consideration should be given to these factors in evaluating ceramic parts. Even if a ceramic engine were manufactured after full consideration (1) to these factors, adiabatic engines proposed by R. Kamo and other researchers have had difficulty in realizing performance level and fuel economy as first suggested. Today, the adiabatic turbo compound engine still has many problems and themes to be addressed, some of which are adiabatic efficiency, combustion rate, intake air rate and method of recovering exhaust gas energy. (2),(3) On the other hand, however, an adiabatic engines with ceramic parts have already reached the stage where they can be actually used on automobiles. Further efforts, therefore, should be concentrated on attacking the aforementioned problems and themes to achieve the levels of performance suggested earlier. This paper is intended to report some part of the studies conducted by the author and his group.
Kawamura, Hideo
A Critical Evaluation of the Geared Hypocycloid Mechanism for Internal Combustion Engine Application8806602/1/1988
The geared hypocycloid mechanism, a kinematic arrangement that provides a straight-line motion, can be used as the basis for an internal combustion engine. Such an engine would have a number of advantages: Perfect balance can be achieved with any number of cylinders. The straight-line motion eliminates the need for a wrist pin bearing, further allowing a very short piston to be used without danger of cocking. Piston side load is virtually eliminated, and “piston slap” will not occur even with a large piston/cylinder clearance. These features make it particularly attractive for small single cylinder engine applications where vibration is undesirable, and also for the uncooled “adiabatic engines”, in which piston cylinder lubrication and friction are major concerns. The paper discusses the history of the concept, the limited engineering development that it has received, limitations and potential weak points of the design, and a presentation of design configurations that appear particularly attractive.
Beachley, Norman H., Lenz, Martha A.
In-Cylinder Components for High Temperature Diesel8701592/1/1987
The development of a practical, reliable, and durable adiabatic engine which will meet all advanced military requirements is still hindered because of available insulating materials and design limitations. The high temperatures and thermal gradients which are associated with a highly insulated low heat rejection engine create monumental challenges to engine designers. Over the past 12 years a wealth of information and experience has been generated. Numerous approaches to insulate the combustion chamber have been explored but none are known to simultaneously meet heat rejection, durability, and performance requirements. This paper will present the first year's results and the future plans of an adiabatic engine component technology development program for high output military engines, sponsored by the U.S. Army Tank-Automotive Command Center. As a result of a systematic process which included technology survey, technical screening, technical trade-off assessment, concept construction, and benefit-burden assessment, three insulating concepts were selected for exploratory assessment.
Woods, Melvin E., Glance, Paul, Schwarz, Ernest
Adiabatic Engine Trends-Worldwide8700182/1/1987
Since the early inception of the adiabatic diesel engine in 1974, marked progress has taken place as a result of research efforts performed all over the world. The use of ceramics for heat engines in production applications has been limited to date, but is growing. Ceramic use for production heat engine has included: combustion prechambers, turbochargers, exhaust port liners, top piston ring inserts, glow plugs, oxygen sensors; and additional high temperature friction and wear components. The potential advantages of an adiabatic engine vary greatly with specific application (i.e., commercial vs. military, stationary vs. vehicular, etc.), and thus, a better understanding of the strengths and weaknesses (and associated risks) of advanced adiabatic concepts with respect to materials, tribology, cost, and payoff must be obtained. As an example, installed vehicular fuel economy for a low heat rejection adiabatic engine can vary from at least 10% improvement to well over 20% depending on application and engine configuration. In the U.S., key research efforts within the adiabatic engine area include: high temperature tribology, brittle material fracture analysis, stochastic finite element stress analysis, transient heat transfer, and methods of designing engine components with ceramic/metal interfaces. Careful characterization of ceramic materials, techniques for low cost machinery/processing of the ceramics, and non-destructive evaluations are also underway. In Japan, the monolithic ceramic engine has been the predominant approach. However, at high output engine conditions, current monolithic ceramics have not lived up to expectations with respect to reliability and cost. In the U.S. and Europe ceramic coatings are drawing greater interest because of low cost and high reliability potential. The trend toward ceramic material/engine manufacturer consortiums appears to be growing on a worldwide basis, with success in the future most likely achieved by those working toward a common goal.
Kamo, Roy, Bryzik, Walter, Glance, Paul
New Connection System Between Ceramic and Metal for Adiabatic Piston Head8604413/1/1986
This paper describe the metal-to-ceramic joining method which is important for building ceramic adiabatic engine and deals with the potential of pistons for use for adiabatic ceramic engine. Although various ceramic-to-metal joining methods have been developed, the chemical bonding method such as brazing and diffusion bonding is not only inferior in complex joining process and heat resistance, but also incapable of attaining the bonding strength of 196Mpa required of engineering ceramics. The ceramic-to-metal bonding attained generally by mechanical method such as staking results in the failure of ceramic bonding face due to a strong shearing force accompanied by the plastic deformation of metal. Therefore, the reduction of the shearing force between the ceramic and metal materials and the improvement of plasticity of the metal are necessary. In this bonding method, after contact between the ceramic and metal, the metal hardness is reduced by an instant heat application to make the metal malleable whereby the metal will be formed in the shape of the ceramic by external force. It is anticipated that the bonding strength will be further improved by providing the ceramic bonding face with grooves. This bonding method offers the features of eliminating the need for selection of ceramic materials, shortening bonding time and being highly durable at a high temperatures. The ceramic adiabatic piston produced by the above method uses the ceramic materials only for the piston head in direct contact with combustion gases and the skirt is made of an inexpensive, tough metal and the piston head and skirt are joined with a high performance heat insulating material interposed between them. Thus, a ceramic piston which is very simple, fully durable and heat insulating has been realized.
Matsuoka, Hiroshi, Kawamura, Hideo, Matsuda, Ryuichi
Computer Aided Engineering Analysis of Adiabatic Engine Components8503612/25/1985
THIS PAPER PRESENTS a description of a general purpose, computer aided engineering design methodology which has been employed in the design of adiabatic engine components. The application of the design methodology is demonstrated through the discussion of the results of a thermal and structural design study. The performance of four piston design options; (1) 100% steel piston with oil-jet cooling, (2) 100% steel with oil-splash cooling, (3) silicon nitride piston cap and steel base with oil-splash cooling, and (4) ZrC2 /Brunsbond/steel composite piston with oil-splash cooling are discussed.
Glance, Paul C.
Cummins/TACOM Adiabatic Englue Program8503562/25/1985
Joint development of the adiabatic engine by Cummins Engine Company and the U. S. Army began with a feasibility analysis ten years ago. The effort was initially driven by the expectation of substantial performance improvement, a reduction in cooling system size, and several additional benefits. Program emphasis turned quickly to experimentation with the goal of demonstrating the feasibility of the adiabatic engine in working hardware. Several significant achievements were realized as have been reported earlier. Further development of the adiabatic engine is expected to be more evolutionary, paced by available technology in the areas of materials and tribology. Analysis capability necessary for insulated engine development has been found to be inadequate. Additional effort has gone into the development and validation of insulated engine analysis tools, both for cycle simulation and structural modeling. Emphasis is being placed on the analysis of design strategies, prior to test, with a view toward incremental adoption of insulating concepts as the technology becomes available.
Hoag, K. L., Brands, M. C., Bryzik, Walter, Army, U.S.
Cummins/TACOM Advanced Adiabatic Engine8404282/1/1984
Cummins Engine Company, Inc. and the U.S. Army have been jointly developing an adiabatic turbocompound engine during the last nine years. Although progress in the early years was slow, recent developments in the field of advanced ceramics have made it possible to make steady progress. It is now possible to reconsider the temperature limitation imposed on current heat engines and its subsequent influence on higher engine efficiency when using an exhaust energy utilization system. This paper presents an adiabatic turbocompound diesel engine concept in which high performance ceramics are used in its design. The adiabatic turbocompound engine will enable higher operating temperatures, reduced heat loss, and higher exhaust energy recovery, resulting in higher thermal engine efficiency. This paper indicates that the careful selection of ceramics in engine design is essential. Adiabatic engine material requirements are defined and the possible ceramic materials which will satisfy these requirements are identified. Examples in design considerations of engine components are illustrated. In addition to these important points, the use of ceramic coatings is described in the design of engine components. The first generation adiabatic engine with ceramic coatings is described. The advanced adiabatic engine with minimum friction features utilizing ceramics is also presented. The advanced ceramic turbocharger turbine rotor as well as the oilless ceramic bearing design is described. Finally, the current status of the advanced adiabatic engine program culminating in the AA750 V-8 adiabatic engine is presented.
Kamo, R., Bryzik, Walter
Post Densified Cr 2 O 3 Coatings for Adiabatic Engine8404322/1/1984
A Cr2O3 impregnation treatment process can be used to densify and strengthen existing coatings and materials and to produce new coatings for use in adiabatic engines. Plasma sprayed zirconia densified with Cr2O3 exhibits an 87% lower wear rate than an undensified plasma sprayed zirconia coating, and a thermal conductivity value of 9.67 BTU -in/hr-ft2 -°F at 1832 °F. A Cr2O3 densified ceramic coating exhibits a thermal conductivity value of 14.9 BTU - in/hr-ft2 -°F at 1500 °F.
Carr, Jeffrey, Jones, Jack
TACOM/Cummins Adiabatic Engine Program8303142/1/1983
This paper discusses the goals, progress, and future plans of the TACOM/Cummins Adiabatic Engine Program. The Adiabatic Engine concept insulates the diesel combustion chamber with high temperature materials to allow hot operation near an adiabatic operation condition. Additional power and improved efficiency derived from this concept occur because thermal energy, normally lost to the cooling and exhaust systems, is converted to useful power through the use of turbomachinery and high-temperature materials. Engine testing has repeatedly demonstrated the Adiabatic Engine to be the most fuel efficient engine in the world with multi-cylinder engine performance levels of 0.285 LB/BHP-HR (48% thermal efficiency) at 450 HP representative. Installation of an early version of the Adiabatic Engine within a military 5 ton truck has been completed, with initial vehicle evaluation successfully accomplished. Design and procurement of long lead time items for the next generation of Adiabatic Engine in the 600-750 HP power range is continuing. Work on the minimum-friction Adiabatic Engine version continues.
Bryzik, Walter, Kamo, Roy
A Review of Engine Advanced Cycle and Rankine Bottoming Cycle and Their Loss Evaluations8301242/1/1983
Turbo aftercooled vehicle engine is widely accepted today. Two-stage turbo intercooled and aftercooled engines up to 300–350 bmep are in initial application stages for some medium speed stationary and marine diesels. Turbo compound engine has been tested and developed; the adiabatic engine concept has recently been advanced. For these advanced diesels, exhaust heat is a major source of engine performance improvement. Rankine bottom cycle has been applied the last few years to stationary engines for further exhaust heat recovery. Due to initial cost, complexity, and reliability of additional heat recovery equipment needed, few prototypes have been installed. Engine cycle exhaust is used as bottom cycle source heat as shown in the illustration below. This simplified H-S diagram gives a birds-eye view of how a basic diesel cycle and Rankine bottom cycle are coupled. The advancement of the adiabatic concept renders interesting potential for additional exhaust heat recovery.
Chen, Simon K., Lin, Rocky
Toughened PSZ Ceramics-Their Role as Advanced Engine Components8303182/1/1983
Toughened partially stabilized zirconia (PSZ) ceramics possess a number of advantageous properties for advanced engine components, in particular for adiabatic engine systems. Magnesia partially stabilized zirconia (Mg-PSZ), is one of the toughest ceramics yet developed also possessing excellent insulating, high strength, good thermal shock and wear resistance properties. In addition PSZ has a thermal expansion coefficient and elastic modulus similar to iron and steel. Over the last three years, it has been shown as a result of the combination of these thermal and mechanical properties, that Mg-PSZ is suitable for applications as varied as cylinder liners, valve guides, valve seats, piston caps, hot plates and tappet (cam follower) inserts. In non-automotive applications this material can be used in extrusion dies, plastic moulding dies, powder metallurgical dies, dry conveyor bearings and prothesis implants.
Marmach, M., Servent, D., Hannink, R.H.J., Murray, M.J., Swain, M.V.
Tribological Investigations for an Insulated Diesel Engine8303192/1/1983
A Minimum Cooled Engine (MCE) has been successfully run for 250 hours at rated condition of 298 kW and 1900 rpm. This engine was all metallic without any coolant in the block and lower part of the heads. Ring/liner/lubricant system and thermal loading on the liner at top ring reversal (TRR) as well as on the piston are presented and discussed. Ring/liner wear is given as well as oil consumption and blow-by data during the endurance run. Another engine build with a different top ring coating and several lubricants suggested that a 1500 hours endurance run of MCE is achievable. Rig test data for screening ring materials and synthetic lubricants necessary for a successful operation of a so-called Adiabatic Engine with the ring/ceramic liner (SiN) interface temperature up to 650°C are presented and discussed.
Radovanovic and, Rod S., Kamo, Roy, Dufrane, Keith F.
PSZ Ceramics for Adiabatic Engine Components8204292/1/1982
Partially stabilized zirconia is an insulating ceramic which offers high strength, high thermal expansion, and wear resistance. Low thermal conductivity provides the required insulation, high strength improves reliability, and high thermal expansion provides a simple means of attachment for ceramic engine components. Pistons, cylinder liners, and cylinder heads have been insulated with PSZ and engine tested in an adiabatic diesel engine.
Woods, M. E., Oda, Isao
The AV1 Series III Diesel-A Differentially-Cooled Semi- Adiabatic Engine Below 10 kW7908442/1/1979
A new type of internal combustion engine has been built which is characterised by reduced cooling of the combustion chamber achieved by using a water-cooled head with a cast iron piston and a liner cooled only by conduction and convection. This paper provides a description of the engine and some experimental results, followed by a discussion of its design and performance features. The outstanding characteristic of the small hp engine is its very low specific fuel and lubricating oil consumption combined with high reliability.
Kirloskar, C. S., Chandorkar, S. B., Narayan Rao, N. N.
Ceramics in Heat Engines7906452/1/1979
Recent developments of high performance ceramics have given a new impetus for the advancement of heat engines. The thermal efficiencies of the Otto, Diesel, Brayton and the Stirling cycle can now be improved by higher operating temperatures, reduced heat loss, and exhaust energy recovery. Although physical and chemical properties of the high performance ceramics have been improved significantly, they still fall short of meeting the requirements necessary for application and commercialization of advanced heat engine concepts. Aside from the need for greater strength, the problems of consistency, quality, design, material inspection, insulative properties, oxidation and other important features must be solved before high performance ceramics can be considered a viable material for advanced heat engines. Several approaches in developing an adiabatic engine design in the laboratory are shown. Other possible future improvements such as the minimum friction unlubricated engine through the use of ceramics are also described.
Kamo, R., Bryzik, Walter
Designing Adiabatic Engine Components7800692/1/1978
A procedure to analyze and design adiabatic diesel engine components is developed. The analytical basis for the procedure is presented. An experimental study of related thermal boundary conditions in the combustion chamber is conducted. Mean effective gas temperatures as high as 2200°F are measured. A new adiabatic diesel piston, using a ceramic top, is designed and demonstrated using the procedure. Initial engine testing of the piston is encouraging, with full design power being achieved. The piston is considered the critical component in the overall development of an adiabatic diesel engine.
Stang, John H.
The Influence of Compression Ratio and Dissociation on Ideal Otto Cycle Engine Thermal Efficiency6205571/1/1962
THIS PAPER PRESENTS a theoretical analysis of the ideal adiabatic Otto cycle engine. The analysis was made to examine the influence of compression ratio and dissociation on engine thermal efficiency over an extreme range of compression ratios (that is, 4–300) to see if chemical dissociation could limit Otto cycle engine thermal efficiency. Assuming isooctane, benzene, ethyl alcohol, and nitromethane to be the fuels being consumed, the effects of compression ratio and mixture strength on the thermodynamic properties and equilibrium species concentration of the working fluid at every step in the ideal Otto cycle were computed. The calculations were made using a mathematical model of the ideal adiabatic engine which had been programmed to an IBM 704 digital computer. With the model, the effect of compression ratio on engine thermal efficiency was calculated over a wide range of operating conditions. The results of the study showed that engine thermal efficiency continued to increase with compression ratio at least up to 300:1 for all the fuels considered. The effect of compression ratio and mixture strength on chemical dissociation was studied using two parameters termed: (1) “Extent of Dissociation” and (2) “Net Energy Loss.” The “Extent of Dissociation” was defined as the deviation from the theoretical concentration of product species when a given fuel air mixture is burned. The “Net Energy Loss” associated with chemical dissociation was defined as the change in internal energy between a burned mixture at chemical equilibrium and the frozen theoretical burned mixture when both are at some selected temperature and pressure level. Both dissociation parameters were examined after combustion at top dead center in the Otto cycle engine at various levels of compression ratio and mixture strength. It was noted, in general, that the “Extent of Dissociation” and “Net Energy Loss” increased with increasing compression ratio. The increase, however, was small. The paper demonstrates that under theoretical and ideal conditions, there is no upper limit to which the compression ratio of the Otto cycle engine can be raised. The reason for this is that any increase in chemical dissociation brought about by increasing temperature is substantially suppressed by the very rapidly increasing pressure levels which result when the compression ratio is increased.
Edson, Murray H.
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