High-temperature Exhaust Gas Research Articles

Performance investigation of two stage Organic Rankine Cycle (ORC) architectures using induction turbine layouts in dual source waste heat recovery

Abstract Improvement in performance of Organic Rankine Cycle (ORC) systems, particularly in the context of dual heat sources such as IC engines, leads to better return on investments. However, the choice of architecture to achieve the best performance is not evident from available literature. When two separate heat sources are present concurrently at different temperature levels with heat contents such as in IC engines, single stage pre-heated ORC and dual loop ORC are the two commonly deployed ORC architectures. In this study, two stage architectures: Series two stage ORC (STORC) and Parallel two stage ORC (PTORC) are analysed and their performance is compared against a single stage pre-heated ORC at sub-critical conditions in the utilization of high temperature (primary) exhaust gases (573–773 K) and low temperature (secondary) jacket water (353–393 K) representing IC engine waste heat conditions. Results show that STORC and PTORC are able to achieve the maximum net power output for an intermediate utilization of secondary heat source. The power output gains from two stage layouts improves significantly with a reduction in heat source temperature difference and for lower ratios of the heat available between the primary to secondary heat source. For a 2.9 MW natural gas IC engine operating at its design point, STORC delivers 8.5% more power output whereas PTORC delivers 0.3% less power output than pre-heated ORC. Compared to a dual–loop ORC, STORC presents a less complex and improved cycle architecture with a 13.1% increased power output and a 27.9% reduced heat exchanger requirements.

Improving filtration and pulse-jet cleaning performance of metal web filter media by coating with polytetrafluoroethylene microporous membrane

The metal web filter media has been widely used to purify high-temperature exhaust gas because of its good durability and reliability. Although it has fine high-temperature resistance, its filtration efficiency for fine particles is relatively low. In this study, we developed a new type of composite filter of metal web coated with polytetrafluoroethylene (PTFE) membrane, which combined the high-temperature resistance of the metal web filter and the excellent filtration performance of the membrane-coated filter media. The performance parameters of the composite filter, including pressure drop, filtration efficiency, regeneration efficiency, adhesive force, and high-temperature resistance, were investigated experimentally, and compared with those of the metal web filter and polyester fiber coated with PTFE membrane filter. Although the composite filter yielded a higher pressure drop, it exhibited a high particle collection efficiency. At a face velocity of 10.23cm/s, the filtration efficiency of the composite filter was 99.32 %. This was 1.23 and 0.10 % higher than that of the metal web filter and polyester coated with PTFE membrane filter, respectively. In addition, the composite filter has the characteristics of small cake/fabric adhesion force, low residual pressure drop, high regeneration efficiency, and long cleaning interval. The average cleaning interval and residual pressure drop of the composite filter were 421s and 425.0Pa, respectively, whereas those of the metal web filter were 291s and 658.5Pa, respectively; those of the polyester coated with PTFE membrane filter were 415s and 443.2Pa, respectively. Furthermore, the filtration test at high temperatures and thermogravimetric analysis demonstrated that the composite filter has an excellent thermal stability. At a temperature of 260°C, the average dust emission concentration of the polyester coated with PTFE membrane filter was 2.86 times larger than that of the composite filter (0.532mg/m3).

Thermal management for chemical looping systems with chemical production

Chemical looping technology is a promising pathway to realize a clean production of value-added chemicals with less energy penalty. Its core concept, utilizing heat storage in the cycled solid materials to maintain an efficient operation, needs further confirmation. Here, a combined thermal management method is firstly proposed to achieve an autothermal operation for chemical looping system. New dual fast fluidized bed reactors with optimal reaction temperatures are designed to match the redox reaction rates, while heat integration and exergy cost assessment are conducted to locate the source of thermodynamic irreversibility and interpret the cost formation process. The heat transfer between high temperature exhaust gases and low temperature inlet streams contributes to the main thermodynamic irreversibility and exergy cost. The external energy demand for system gets a maximum 62.37% decrement, the exergy efficiency shows a maximum 9.00% increment and the unit exergy cost for oxygen production gains a maximum 42.18% decrement.

Status, technological progress, and development directions of the ironmaking industry in China

ABSTRACTThe ironmaking industry in China is developing rapidly. This paper discusses the status, technological progress, issues, and possible development directions of ironmaking in China. Because the standards for waste discharge and energy consumption have become more redundant, the steel production capacity has decreased by ∼145 million tons from 2016 to 2018. New sintering and coking technologies, such as water vapour spray sintering, high-temperature exhaust gas sintering, and semi-coke utilization, have led to distinct energy and efficiency improvements. Moreover, blast furnaces (BFs) are becoming larger and more intensive, due to which labour productivity has increased noticeably. However, some issues still remain, such as high fuel ratios, hot blast temperatures, and BF longevity. Nevertheless, eco-friendly and intelligent ironmaking is gaining importance and could be the development directions of the future.

Performance Analysis of Direct Injection Diesel Engine Fueled with Diesel-Tomato Seed Oil Biodiesel Blending by ANOVA and ANN

Biodiesel is an alternative fuel for diesel engine. Considering the differences between diesel and biodiesel fuels, the engine condition should be modified based on the fuel or fuel blends to achieve optimum performance. This study presented a performance analysis of a direct-injected (DI) diesel engine with a dynamometer fueled with diesel-tomato seed biodiesel (TSOB) blends employing ANOVA and universal nonlinear model based on ANN. The experiments were carried out under conditions of some independent variables including different engine loads (0, 50, 100%) and speed (1800, 2150, and 2500 rpm) for four diesel-biodiesel combinations (B0, B5, B10, and B20). In this research, the effect of these factors on dependent variables including power, torque, SFC, FC, and Exhaust Gas Temperature (EGT) are investigated. Duncan′s multi-domain test at a significance level of R < 0.01 shows that the highest and lowest of the torque and power are produced from B5 and B20, respectively. These results show that the lowest EGT of 613 K is related to B20 and the highest EGT is related to B5 and B10. The regression models showed that the torque decreases with increasing the engine speed and biodiesel percentage. These results also show that the highest and the lowest SFC is related to B0 and B20, respectively. The ANN model shows high capability of predicting the engine performance parameters and emissions, without running costly and time-consuming experiments with the histogram error of 0.004 and R = 0.96. It also proved that ANN is a non-linear model of choice to deal with these data, instead of multivariate linear regression employed for preliminary analysis.

Pilot-Scale NOx and SOx Aftertreatment Using a Two-Phase Ozone and Chemical Injection in Glass-Melting-Furnace Exhaust Gas

As NOx and SOx have significant environmental impacts, advanced treatments are required to remove them from the exhaust gas of a glass melting furnace. Here, we investigate a plasma-chemical hybrid process (PCHP) for this purpose. A pilot-scale experiment of the simultaneous removal of NOx and SOx using a PCHP combined with the existing semi-dry type desulfurization reactor is conducted on actual high-temperature exhaust gas from a glass melting furnace. NO (the majority of NOx exist as NO) in the exhaust gas is oxidized to NO2 using active oxygen (ozone: O3) generated by a plasma ozonizer. The exhaust gas must be cooled to less than 150 °C in order to suppress the thermal decomposition of O3, while the gas temperature at the outlet of the semi-dry reactor must be kept at 200–;250 °C to protect the dry-type electrostatic precipitator. Therefore, it is important to form a local cooling area for NO oxidation in the reactor. In this article, we use the three-fluid nozzles of O3, water, and air to form the local cooling area and effectively oxidize NO to NO2. In addition, we spray NaOH aqueous solution for SO2 absorption downstream of the NO oxidation area to allow sufficient time for NO oxidation. The SO2 reacts with NaOH to produce Na2SO3, a powerful reducing agent. Subsequently, NO2 reacts with Na2SO3 and is reduced to N2, and the Na2SO4 generated in this reaction is reused as a clarifier of the raw materials for glass manufacturing. As a result, the ratio of the amount of removed NO and NOx to the amount of injected O3 (de-NO/O3 and de-NOx/O3) is 64% and 78%, respectively; therefore, high efficiency is obtained. This article includes actual examples of the treatment of exhaust gas in a glass melting furnace, using PCHP de-SOx and de-NOx technologies along with results from pilot-scale experiments.

Numerical analysis of flow characteristics and heat transfer of high-temperature exhaust gas through porous fins

Engine waste heat recovery technology based on thermodynamic cycles calls for highly compact and effective exhaust-gas heat exchangers, especially in the space-constrained applications. A porous fins heat exchanger was proposed and compared with the traditional solid fins heat exchanger in order to effectively enhance the heat transfer and realize the lightweight design. A three-dimensional model of the porous fins exhaust gas heat exchanger under forced convection has been developed and numerically investigated based on the Darcy-Forchheimer-Brinkman momentum equation and local thermal non-equilibrium energy equation. Computational studies are carried out to compare the hydraulic and thermal performance between the porous fins and solid fins of equal size at Reynolds number ranging from 5000 to 50,000. Results show that the porous fins heat exchanger greatly improves by 73.2–77.1% while brings an increase of 15.1–18.5% in the pressure drop. In terms of overall performance, the weight of porous fins heat exchanger is reduced by 90%, and the comprehensive performance factor measuring heat transfer and pressure drop is increased by 41% compared with solid fins heat exchanger. Subsequently, the effects of porous fins height, porous fins density, the porosity and pore density on the heat exchanger performances are also discussed. It is found that there is an optimal fin height to achieve the best comprehensive performance of porous fins heat exchanger.

Improvement of NOX Reduction Rate of Urea SCR System Applied for an Non-Road Diesel Engine

Urea SCR technology has been widely used to reduce NOx emissions of diesel engines. Despite remarkable development for decades, more advanced control and optimization of urea SCR systems are still required as global NOx emissions standards are expected to become more stringent. This study investigated several influential parameters of urea SCR system to improve NOx reduction efficiency. This study uses a commercialized UWS (Urea Water Solution) supply system and a SCR catalyst which was installed in the exhaust line of a non-road CRDI (Common Rail Direct Injection) diesel engine. From this study, it was found that the low space velocity of SCR catalyst is essential for high NOx reduction efficiency, especially at low temperatures. Early injection of UWS enhances the overall NOx reduction efficiency if UWS injection was carefully controlled to avoid urea deposits. Rich injection of UWS with AOC is a good strategy for high NOx reduction efficiency. However, NOx reproduction in the AOC, which has an adverse effect on the overall NOx reduction rate, occurs at high exhaust gas temperatures. System insulation also can improve the NOx reduction efficiency by a few percentage points.

The performance of turbocharged diesel engine with injected calophyllum inophyllum methyl ester blends and inducted babul wood gaseous fuels

The current investigation briefly elaborates usage of calophyllum inophyllum biodiesel and babul-derived gas on a turbocharged diesel engine operated in dual fuel mode taking into consideration two different phases of operation. Initially, the experimentation was to be carried out keeping the gas flow rate fixed at 21.58 kg/h with varying loading condition in contrast to the naturally aspirated mode. Secondly, the gas flow rate was varied for all the fuels with fixed optimal loading conditions at 3.77 kW. Meanwhile, the modified operating parameters such as injection timing (230bTDC), injection pressure (240 bar), combustion chamber (TrCC), nozzle hole geometry (4-hole) were kept constant throughout the set of experimentations. The present work describes the novelty of varying the gas flow rate techniques with modified engine parameters in order to discuss the overall performance, and emission and combustion behavior in contrast to conventional diesel fuel. The result concludes a lower thermal efficiency (BTE) for B20 + P gas (21.58 kg/h) of 2.7%↓ while higher exhaust gas temperature (EGT) and brake specific energy consumption (BSEC) of 3.7%↑ and 2.18%↑ at 3.77 kW than diesel + P gas. Additionally, considering emission analysis, carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC), nitric oxide (NO) and smoke opacity delivers a lower emission range for B20 + P gas of about 24.4%↓, 7.14%↓, 60.8%↓, 14.28%↓ and 42.8%↓ in comparison to diesel + P gas at optimal loading conditions. Moreover, varying the producer gas flow rate depicted a lower BTE and higher BSEC, EGT for B20 at maximum flow rate of 21.58 kg/h was 7.6%↓, 1.7%↑and 6.7%↑ in contrast to conventional fuel. Furthermore, CO, CO2, HC, NO and smoke opacity delivers a very low emission range of 15.2%↓, 8.42%↓, 20.5%↓, 29.6%↓ and 49.3%↓ in contrast to diesel fuel in dual fuel mode. Hence, considering the above discussion, engine with optimal load of 3.77 kW and gas flow rate of 21.58 kg/h along with modified engine parameters as discussed above enhanced the engine’s overall performance. This provides a freedom from using conventional resources resulting in both diesel fuel savings and energy security for future development.

Investigation of petro-diesel, waste animal fat biodiesel with waste cooked oil biodiesel different blends in single cylinder four-stroke water-cooled CI engine

ABSTRACT The present paper investigates the performance, combustion and emission analysis of various biodiesel blends prepared from animal fat methyl ester (AF100) and waste cooked oil (WCO) 8–10 h used. A single cylinder, four-stroke, water-cooled, compression ignition (CI) engine was used in this investigation. Blends were prepared differently, by mixing of prepared biodiesels in various proportions. The AF100 and WCO are prepared through transesterification process. In the preparation of AF100 and WCO, catalyst potassium hydroxide (KOH) and alcohol methanol are used. The prepared AF100r was blended with WCO and petro-diesel (PD) in various proportions such as AF50WCO50 (50% of AF100 and 50% of WCO), PD50AF30WCO20 (50% of PD, 30% of AF100 and 20% of WCO) and PD50AF50 (50% of AF100 and 50% of PD). Few important properties were tabulated and compared with PD. Performance, combustion and emission tests were carried out with the above-prepared blends and compared with PD. From the tests, it was observed that PD50AF30WCO20 consumes lesser brake-specific fuel consumption and produced higher brake thermal efficiency compared to other tested blends. PD50AF50 develops higher cylinder pressure which emits more amount of CO2. 30% higher exhaust gas temperature is found in AF50WCO50 and 28% higher of CO, 22% of lower amount of unburned hydrocarbons was found in the blend. PD50AF30WCO20 develops a maximum amount of heat release rate with lower amount of CO, NO x and smoke emission compared to other blends. After completion of these investigations, it is concluded that PD50AF30WCO20 is a better suitable blend of two biodiesels used in CI engines without any modification.

Theoretical analysis of a regenerative supercritical carbon dioxide Brayton cycle/organic Rankine cycle dual loop for waste heat recovery of a diesel/natural gas dual-fuel engine

Supercritical carbon dioxide Brayton cycle is considered one of the most promising systems for waste heat recovery of engines because of its compactness and high energy efficiency. To further improve the fuel utilization ratio and solve the difficulties of waste heat recovery of high temperature exhaust gas, a regenerative supercritical carbon dioxide Brayton cycle/organic Rankine cycle dual loop is proposed for cascade utilization of exhaust heat from a dual-fuel engine. The regenerative supercritical carbon dioxide Brayton cycle of the proposed system is powered by the waste heat contained in the exhaust gas. The working fluid in the organic Rankine cycle is pre-heated by CO2 exiting the regenerator and then further heated by the residual heat of the exhaust gas. The flow rates of the working fluids in both sub cycles are adjusted to match the waste heat recovery system to respond to the changing conditions of the dual-fuel engine. The results revealed that the maximum net power output of this system is up to 40.88 kW, thus improving the dual-fuel engine power output by 6.78%. Therefore, such a regenerative supercritical carbon dioxide Brayton cycle/organic Rankine cycle dual loop system design enables the thorough recovery of high temperature exhaust heat, leading to higher energy efficiency and lower fuel consumption of the engine.

Effect of Dominant Fatty Acid Esters on Emission Characteristics of Waste Animal Fat Biodiesel in CI Engine

This present study aims in understanding the influence of dominant fatty acid esters of waste animal fat biodiesel on its emission characteristics in CI engine. Biodiesel was produced from waste animal fat by means of base catalysed transesterification; and Ethyl oleate (40.21%), ethyl palmitate (25.36%) and ethyl stearate (16.87%) were characterized as dominant fatty acid esters using GC spectra. Test samples were prepared for these ester molecules based on their availability, in addition to biodiesel blend and plain diesel and were tested for their emission levels in single cylinder four stroke CI engine using flue gas analyser. High exhaust gas temperature was contributed by Ethyl oleate (1.15% lesser than biodiesel), as a result of low cetane number due to unsaturation and high viscosity. Likewise, the increased carbon chain length and unsaturation of ethyl oleate (2.55% lesser than biodiesel) resulted in high concentration of CO emission for biodiesel whereas high CO2 emission concentration was because of ester molecules with increased carbon chain length (stearate and Oleate esters). Reduced NOX emission for biodiesel was as a result of higher cetane number from ethyl stearate (CN=86.83) and ethyl palmitate (CN=86.55), which reduced its ignition delay thereby moderating the heat release rate. In addition, long carbon chained ester molecules (oleate and stearate esters) in biodiesel consumed more oxygen content for improving overall rate of combustion while increased HC emission was explained by unsaturation in biodiesel because of ethyl oleate (on average ,50 PPM).

Study on methane steam reforming coupling high-temperature exhaust heat utilization for hydrogen production

ABSTRACTMethane steam reforming coupling high-temperature exhaust gas as heat source for hydrogen production in an integrated reactor composed of the reforming channel and exhaust gas channel was studied with Computational Fluid Dynamics simulation. In this paper, the reactor performance, such as methane conversion rate, hydrogen yield, temperature, thermal efficiency, and reaction rate distribution were obtained with the optimization of inlet parameters and fluid flow in both channels. Results showed that the inlet temperature and velocity of the exhaust gas had an important effect on the reactor performance. However, its performance was not significantly affected by fluid flow modes and inlet feed reactant temperature. The reaction rate and heat flux were the highest at the reactor inlet, and then decreased along the flow direction. Simulation results could be used in the design and optimization of methane reforming reactors coupling waste heat utilization for hydrogen production.

Application of a mid-/low-temperature solar thermochemical technology in the distributed energy system with cooling, heating and power production

A new solar-assisted cooling, heating and power (CCHP) system is developed for improving the energy conversion efficiency in this work. Solar thermal energy (250–350 °C) collected by a parabolic trough solar collector is used to drive the thermochemical reaction of methanol decomposition, then the generated solar fuel in the form of syngas is fed into an internal combustion engine (ICE) to generate electricity. The high-temperature exhaust gas released by the ICE is used to produce cooling and heating energies via a double-effect LiBr-H2O absorption refrigerator and a heat exchanger. Solar energy is converted to chemical energy in the form of syngas, the distinct advantages of energy cascade utilization and thermochemical storage can be realized. Numerical simulation results show that in the proposed CCHP system the energy and exergy efficiencies at the designate condition are 82.0% and 58.72%, respectively. The off-design performances are investigated by deploying the proposed CCHP system to a shopping center building, the annual efficiency and the solar fraction reach 53.6% and 9.81%, respectively. In comparison with the reference solar-assisted CCHP system, the annual methanol consumption of the proposed CCHP system decreases to 874.31 tons with the fuel saving ratio of 4.56% and less CO2 emission. This novel solar CCHP system presents a promising cost-effective performance and the system life cycle cost saving ratio reaches 2.84%. The research findings provide an alternative route towards efficiently utilizing solar energy.

Availability of NH3 adsorption in vanadium-based SCR for reducing NOx emission and NH3 slip

This study was carried out to analyze the amount of NH3 adsorption by selective catalytic reduction using various methods for the development of an optimized urea injection control logic. The maximum adsorbable amount, available adsorption amount for NOx reduction, and maximum adsorption amount before NH3 slip were separately measured. The results of the three types of adsorption amounts show that the optimum operating range for urea control gradually narrowed for high exhaust gas temperatures. Furthermore, it was found to be particularly challenging to completely remove NH3 slip without ammonia oxidation catalyst in the transient operation of the engine.

Experimental and Numerical Investigations in a Gas-Fired Boiler With Combustion Stabilizing Device

The combustion stability has a significant influence on safety and reliability of a gas-fired boiler. In this study, a numerical model was first established and validated to investigate the effect of combustion stabilizing device on flow and combustion characteristics of 75 t/h blast furnace gas (BFG) and coke oven gas (COG) mixed-fired boiler. The results indicated that the device coupled with four corner burners enables the flame to spin upward around its side surface, which facilitates heat exchange between BFG and the device. Under stable combustion condition, the combustion stabilizing device can be used as a stable heat source and enhance heat exchange in the furnace. Then, to obtain optimal COG ratio, combustion process of different blending ratios were experimentally investigated. The experimental results revealed that the energy loss due to high exhaust gas temperature is relatively high. COG ratio should be set up taking into account both boiler efficiency and NOX emissions. When COG blending ratio is maintained about 20%, the thermal efficiency of the boiler is 88.84% and the NOX concentration is 152 mg/m3 at 6% O2, meeting NOX emissions standard for the gas boiler.

Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of a heavy-duty diesel engine

Miller cycle has been shown as a promising engine strategy to reduce in-cylinder nitrogen oxide (NOx) formation during the combustion process and facilitate its removal in the aftertreatment systems by increasing the exhaust gas temperature. However, the level of NOx reduction and the increase in exhaust gas temperature achieved by Miller cycle alone is limited. Therefore, research was carried out to investigate the combined use of Miller cycle with other advanced combustion control strategies in order to minimise the NOx emissions and the total cost of ownership. In this article, the effects of Miller cycle, exhaust gas recirculation, and post-injection were studied and analysed on the performance and exhaust emissions of a single cylinder heavy-duty diesel engine. A cost–benefit analysis was carried out using the corrected total fluid efficiency, which includes the estimated urea solution consumption in the NOx aftertreatment system as well as the fuel consumption. The experiments were performed at a low load of 6 bar net indicated mean effective pressure. The results showed that the application of a Miller cycle–only strategy with a retarded intake valve closing at −95 crank angle degree after top dead centre decreased NOx emissions by 21% to 6.0 g/kW h and increased exhaust gas temperature by 30% to 633 K when compared to the baseline engine operation. This was attributed to a reduction in compressed gas temperature by the lower effective compression ratio and the in-cylinder mass trapped due to the retarded intake valve closing. These improvements, however, were accompanied by a fuel-efficiency penalty of 1%. A further reduction in the level of NOx from 6.0 to 3.0 g/kW h was achieved through the addition of exhaust gas recirculation, but soot emissions were more than doubled to 0.022 g/kW h. The introduction of a post-injection was found to counteract this effect, resulting in simultaneous low NOx and soot emissions of 2.5 and 0.012 g/kW h, respectively. When taking into account the urea consumption, the combined use of Miller cycle, exhaust gas recirculation, and post-injection combustion control strategies were found to have relatively higher corrected total fluid efficiency than the baseline case. Thus, the combined ‘Miller cycle + exhaust gas recirculation + post-injection’ strategy was the most effective means of achieving simultaneous low exhaust emissions, high exhaust gas temperature, and increased corrected total fluid efficiency.

Performances evaluation of a mid-/low-temperature solar thermochemical system with cooling, heating and power production

Abstract A novel solar-assisted combined cooling, heating and power (CCHP) system is developed for improving the energy conversion efficiency in this work. Solar thermal energy (250-350℃) collected by the parabolic trough solar collector is used to drive a thermochemical reaction of methanol decomposition, then the generated solar fuel of syngas is fed into an internal combustion engine (ICE) to generate electricity. The high-temperature exhaust gas released from the ICE is used to produce cooling and heating energies via a double-effect LiBr-H2O absorption refrigerator and heat exchangers. The introduced solar energy is converted to chemical form of syngas and replaces a part of fossil fuel. The numerical simulation of the novel CCHP system is carried out, and the system energy efficiency and exergy efficiency at the designate condition are 77.69% and 55.94%, respectively. The system off-design performances are investigated by deploying it to a shopping center building, and the system annual efficiency reaches to 49.29% with the solar fraction of 11.58%. As compared with the typical CCHP systems with direct methanol combustion, the annual methanol consumption of the proposed system decreases to 895.15 tons, with the fuel saving ratio of 6.11%. The research findings provide a promising way for the cascade utilization of solar energy, and broaden its applications in distributed energy systems.

Combustion characteristics, performances and emissions of a biodiesel-producer gas dual fuel engine with varied combustor geometry

This paper presents the overall performance, emission and combustion characteristics of the engine, when fuelled with biodiesel blends of Calophyllum Inophyllum methyl ester as injected fuel and babul wood chip derived producer gas as inducted fuel at constant injection timing (230bTDC), injection pressure (230 bar) and speed (1500 rpm). To improve overall performance, combustion and reduced emission characteristics of the engine, the combustion chamber was varied with 5 different geometries. Experimental results revealed that Toroidal re-entrant combustion chamber had higher Exhaust Gas Temperature and Brake Thermal Efficiency by 20.75% and 6.37% than that of HCC, while Brake Specific Fuel Consumption was reduced by 4.49% at optimal loading condition. However, engine overall performance of TrCC was found to be comparable with Hemi-spherical chamber and other designed combustion chambers. Similarly, comparing exhaust emissions, Oxide of Nitrogen and Carbon dioxide were on its higher side by 19.90% and 27.20% than normal HCC. On the contrary, carbon monoxide, Hydrocarbon and Smoke opacity for TrCC were found to be 76.12%, 33.71% and 38.67% lower than HCC. From the above study, it is finally concluded that converted renewable fuels with TrCC might be utilized as an alternative fuel without any exhaust related problems.

Effects of V or Cu Addition on High-Temperature Tensile Properties of High-Ni-Containing Austenitic Cast Steels Used for High-Performance Turbo-Charger Housings

For maintaining high-performance turbo-charger housings at higher exhaust-gas temperatures, e.g., 1050 °C, a high-Ni(20 wt%)-containing austenitic steel (ASTM HK40 steel) has been actively modified. As a promising method, the solid-solution hardening obtained from the V or Cu addition was utilized in this study. Five austenitic cast steels were made by adding V or Cu in the modified HK40 steel (N16 steel; 4%-Ni replacement by 4.6%-Mn), and the high-temperature property improvement was explained by detailed microstructural evolutions coupled with thermodynamically calculated phase diagrams. The V- or Cu-added steels showed improvements in high-temperature properties over the N16 steel because the addition of V or Cu raised both austenite matrix hardness and volume fraction of M7C3 carbide. Considering that only 3.6–4.8 vol% of M7C3 was present in the five austenitic cast steels, the strengths were affected more by the matrix hardness. When the V or Cu content was quite high, however, the ferrite or Cu-coring is formed, thereby leading to the serious deterioration of high-temperature properties. The V- or Cu-added steels within proper contents are applicable well to automotive turbo-charger housings requiring or emphasizing high-temperature tensile properties.