Low Temperature Combustion Research Articles

Experimental and kinetic study of pyridine oxidation under the fuel-lean condition in a jet-stirred reactor

Pyridine is an important model compound of fuel-nitrogen during the coal combustion process. The lean oxidation of pyridine was studied over 800–1100 K at atmospheric pressure with the equivalence ratio of 0.4 in a jet-stirred reactor. Pyridine and its oxidation products were measured by tunable synchrotron vacuum ultraviolet photoionization molecular-beam mass spectrometry and gas chromatography analyzer. Three-stage consumption phenomenon of pyridine and O2 was observed including a fast consumption stage at 910–920 K, a moderate consumption stage at 920–1000 K, and a slow consumption stage at 1000–1100 K. HCN, N2, N2O, and HNCO are the major nitrogenous oxidation products of pyridine. CO, CO2, HCN, and HNCO are the dominant carbonaceous products. HNCO is uniquely detected in the lean oxidation of pyridine compared with rich oxidation. A new pyridine LTO 2.0 model comprising 210 species and 1349 reactions was proposed, providing a good prediction of pyridine and its major oxidation products against experimental data. N2O emission is larger than NO at 1100 K. HCN is the dominant nitrogenous intermediate under both fuel-lean and fuel-rich conditions. Results of this work provide a detailed analysis of the nitrogen evolution mechanism of pyridine oxidation under the fuel-lean condition, which is close to the real industrial low-temperature coal combustion processes including the MILD combustion, fluidized bed combustion, etc.

Novel strategies to extend the operating load range of a premixed charge compression ignited light-duty diesel engine

Low-temperature combustion (LTC) is an alternative combustion mode to conventional diesel combustion (CDC) that offers a simultaneous reduction in oxides of nitrogen (NOx) and particulate matter (PM) emissions while retaining higher thermal efficiency. Premixed charge compression ignition (PCCI) is a promising LTC strategy that utilizes the early direct injection of diesel and exhaust gas recirculation (EGR) to reduce NOx and PM emissions simultaneously. A limited operating load range and high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are the significant shortcomings to be addressed to realize PCCI as a commercially viable option. The present work aims to address these limitations based on experimental investigations carried out in a production light-duty diesel engine. An existing mechanical fuel injection system is replaced with a flexible common rail direct injection (CRDI) system to implement PCCI in the test engine. Based on initial parametric investigations, it was found that a combination of early direct injection, lower injection pressures, and EGR was deemed necessary to achieve PCCI mode in the test engine. However, the achievable load range was limited to 40% of the rated load, along with high HC and CO emissions. Novel approaches are attempted to address these limitations, including replacing diesel with diesel-gasoline blends with 30% gasoline by volume and utilizing a dual charge dilution strategy with water vapour induction and EGR. The start of fuel injection (SOI) sweeps from 30 to 70 deg. CA bTDC were performed to find optimal timing at each load condition to maximize the thermal efficiency within a stable combustion regime between a misfire and knocking. For loads above 40%, EGR in the range of 14% to 26.5% was used to bring the combustion within knock limits. By combining the proposed novel strategies, the engine operating load range could be extended from 40% to 80% of the rated load in PCCI. The NOx and soot emissions were significantly reduced up to 98.5% and 99.1%, respectively, compared to CDC. The engine brake thermal efficiency is increased by up to 1.6%. However, there was a significant penalty regarding HC and CO emissions.

Effects of deep eutectic solvent on Cu-Mn-C-O composite catalysts: Surface species, physical and chemical properties in methane combustion

A series of Cu-Mn-C-O composite catalysts for low-temperature catalytic combustion of methane were successfully prepared by synthetic induction of CuMn2O4 precursors via hydrothermal method which used deep eutectic solvent (DES) as an inducer. The structure and properties of the catalyst were investigated by XRD, BET, XPS and SEM characterizations to investigate the effect of DES addition on the crystal growth of the catalyst. The results showed that the Cu-Mn-C-O composite catalyst produced a new phase of MnCO3, which changed the number and distribution of acid-base sites on the catalyst surface and effectively promoted the desorption of catalytic reaction products. The catalytic activity test showed that the methane catalytic activity of the Cu-Mn-C-O composite catalyst was significantly enhanced at Mn/C molar ratio of 1:2.5, with T50 and T90 values of 365 °C and 425 °C, respectively. This can be attributed to the high proportional distribution of high-valent manganese in the internal electronic structure of the composite catalyst system, which generated a large number of surface adsorbed oxygen species and thus facilitated the oxidation of methane at lower temperatures. Thermal analysis of composite catalysts revealed relatively high activation energy and thermal stability in the combustion process of composite catalysts. This study will lead to innovative insights into the design of composite catalysts for methane oxidation.

Towards a comprehensive understanding of mode transition between biodiesel-biobutanol dual-fuel ICCI low temperature combustion and conventional CI combustion – Part Ⅰ: Characteristics from medium to high load

This research work studied the mode switching between ICCI low temperature combustion and conventional CI combustion in a single-cylinder diesel engine. The combustion characteristics during the mode switching process with various control parameters, such as injection timing, numbers, duration, exhaust gas recirculation (EGR) rates, were detailed analyzed at medium and high engine loads. Experimental results show that the smoothness mode switching between ICCI combustion and CI combustion can be achieved within one cycle after switching another combustion mode at medium and high engine loads, and less fluctuation of IMEP is observed. At medium load, there is a wide range of butanol energy ratio (EButanol) to achieve smooth mode transition with stable combustion. However, at high engine load, higher EButanol and earlier biodiesel second direct injection timing are inadequate for the mode transition because of the higher combustion noise. EGR strategy is used to improve the smoothness of CA50 and exhibit NOx emissions. It is not needed the cycle-by-cycle injection modulation to achieve the smoothness of CA50 and the same level of NOx emissions when the EGR rate is 34.2% under ICCI combustion and 37.6% under CI combustion, respectively, with insignificant changes of IMEP and acceptable maximum pressure rise rate.

Numerical Simulation Analysis of Heating Effect of Downhole Methane Catalytic Combustion Heater under High Pressure

The hot exhaust gas generated by a downhole combustion heater directly heats the formation, which can avoid the heat loss caused by the injection of high-temperature fluid on the ground. However, if the temperature of the exhaust gas is too high, it may lead to the carbonization of organic matter in the formation, which is not conducive to oil production. This paper proposes the use of low-temperature catalytic combustion of a mixture of methane and air to produce a suitable exhaust gas temperature. The simulation studies the influence of different parameters on the catalytic combustion characteristics of methane and the influence of downhole high-pressure conditions. The results show that under high-pressure conditions, using a smaller concentration of methane (4%) for catalytic combustion can obtain a higher conversion efficiency (88.75%), and the exhaust temperature is 1097 K. It is found that the high-pressure conditions in the well can promote the catalytic combustion process of the heater, which proves the feasibility of the downhole combustion heater for in situ heating of unconventional oil and gas reservoirs.

2-Stroke RCCI Engines for Passenger Cars

Reactivity Controlled Compression Ignition (RCCI) is one of the most promising solutions among the low temperature combustion concepts, in terms of thermal efficiency and pollutant emissions. However, for values of brake mean effective pressure higher than 10 bar, in-cylinder peak pressure rise rates tend to be too high, limiting the specific power of any 4-Stroke (4S) engine. Such a limitation can be canceled by moving to the 2-Stroke (2S) cycle. Among many alternatives, the “Uniflow” scavenging system with exhaust poppet valves on the cylinder head allows the designer to reproduce the same identical combustion patterns of a 4-stroke RCCI engine, while increasing the indicated power output. The goal of the paper is to explore the potential of a 2-stroke RCCI engine, on the basis of a comprehensive experimental campaign carried out on a modified automotive 2.0 L, 4-stroke, four-cylinder, four-valve diesel engine. The developed prototype can run with one cylinder operating in 4-stroke RCCI mode (gasoline–diesel), while the others work in the standard diesel mode. A One Dimensional-Computational Fluid Dynamics (1D-CFD) model has been built to predict the performance of the same prototype, when operating all four cylinders in RCCI mode. In parallel, an equivalent 2-stroke RCCI virtual engine has been developed, by means of 1D-CFD simulations and empirical assumptions. A numerical comparison between the 4S and the 2S engines is finally presented, in terms of performance and emissions at full load. The study demonstrates that a 2S RCCI engine can maintain all of the advantages of the RCCI combustion, strongly reducing the penalization in terms of performance, in comparison to a standard 4S diesel engine.

Fuel-reforming effects on a gasoline direct injection engine under a low-temperature combustion mode: Experimental and kinetics analyses

Dedicated in-cylinder reforming where gasoline fuel is injected directly into a rich mixture can control the combustion of gasoline engines. This work investigates the effects of injection parameters and in-cylinder fuel reforming on a gasoline direction injection (GDI) engine operated under low-temperature combustion mode. The single-cylinder research engine is modified from a dedicated 4-cylinder spark-ignited engine used in subcompact passenger vehicles. Experimental and kinetics results on direct fuel injection into an oxygen-depleted environment of the engine’s recompression interval are analyzed under 0.53 MPa indicated mean effective pressure and 1500 RPM. Zero-dimensional kinetics simulations show that the recompression reactions are net endothermic under near-stoichiometric environments. Substantial short-chain hydrocarbons (CH4, C2H4, C3H6) are reformed, while CO and H2 are small under the O2-depleted environment. These kinetics reformates strongly depend on the start of injection timing (SOI). Consequently, the kinetics species shorten predicted ignition delays and play a significant role in advanced combustion phasing. Validated 3D-CFD results further indicate the effects of these reformates on advanced combustion. Experimentally, SOI, injection pressure Pinj = 5 and 6 MPa, single/double pulses injection, and mixture equivalence ratios ϕ are varied in the recompression and intake strokes. Underϕ = 0.97, excessive ringing intensities (RI) over 5 MW/m2 are observed under advanced SOIs. The fierce combustion, excessive combustion noise metrics, NOx emissions can be reduced significantly by retarding SOI, double-pulse injection, and ϕ variations. Under ϕ < 0.67, measured NOx emissions are below 10 ppm. For all pulse-injection strategies, the peak recompression pressures are dropped by up to 13% lower than 2.0 MPa of the motoring pressure, indicating that the net endothermic reactions occur during the recompression. Therefore, the reformed products chemically control the main combustion, and 41 % indicated thermal efficiency is achievable.

Development of an empirical test method to quantify the ɸ-sensitivity of liquid fuels

Several researchers are investigating strategies to lower the emissions and increase the efficiency of combustion engines to reduce the negative impact on the environment and the climate from transportation. The low-temperature combustion (LTC) concept is the basis for some of these high-efficiency, low-emission combustion technologies. To maximize the combustion controllability of engines based on the LTC concept, the combustion behavior of fuel both at different equivalence ratios (ɸ) and under ɸ sweeps must be understood and planned precisely. The ɸ-sensitivity of a fuel explains its behavior at different engine loads or stratification levels. In this study, a new test method for empirically evaluating ɸ-sensitivity using a Cooperative Fuel Research (CFR) engine is proposed and the validity of the method is investigated. A modified CFR engine for homogeneous-charge compression ignition (HCCI) combustion is used to investigate the compression ratio (CR) sensitivity of different toluene–ethanol reference fuels (TERFs) in a research octane number (RON) range of 63–105. This study suggests a method to quantify the ɸ-sensitivity of different fuels and blends by measuring the compression ratio required to keep the CA50 constant while varying ɸ. It shows that the fuel composition greatly affects the fuel ɸ-sensitivity even for different blends with the same RON. The results also indicate that the coexistence of ethanol and toluene in a blend can generate the highest ɸ-sensitivity of the blend compared to other blends with the same RON. Fuel composition has a strong effect on emissions. The simultaneous effect of fuel composition and ɸ variation on the emission and stability parameters is nonlinear.

Combustion, Pyrolysis, and Gasification of Waste-Derived Fuel Slurries, Low-Grade Liquids, and High-Moisture Waste: Review

The article discusses the modern achievements in the field of thermal recovery of industrial and municipal waste. The average accumulation rate and calorific value of typical wastes were analyzed. The focus is on the opportunities to exploit the energy potential of high-moisture waste, low-grade liquid components, and fuel slurries. We consider the relevant results in the field of combustion, pyrolysis, and gasification of such fuels. The main attention is paid to synergistic effects, the influence of additives, and external conditions on the process performance. Vortex combustion chambers, boilers with burners, and nozzles for fuel injection, grate, and fluidized bed boilers can be used for the combustion of waste-derived liquid, high-moisture, and slurry fuels. The following difficulties are possible: long ignition delay, incomplete combustion, low combustion temperature and specific calorific value, high emissions (including particulate matter, polycyclic aromatic hydrocarbons), fast slagging, and difficult spraying. A successful solution to these problems is possible due to the use of auxiliary fuel; boiler modifications; oxy-fuel combustion; and the preparation of multi-component fuels, including the use of additives. An analysis of methods of waste recovery in the composition of slurries for fuel gas production showed that there are several main areas of research: pyrolysis and gasification of coal–water slurry with additives of oil waste; study of the influence of external conditions on the characteristics of final products; and the use of specialized additives and catalysts to improve the efficiency of the pyrolysis and gasification. The prospects for improving the characteristics of thermochemical conversion of such fuels are highlighted.

On promoted combustion stability of kerosene/ethanol blends at wide low temperatures: Fuel reactivity improvement and Leidenfrost effect suppression

Despite the progress in interpretation of Leidenfrost effect suppression for heat transfer enhancement, a knowledge gap still exists in explaining its effects on low-temperature combustion of practical fuels that is heat-related. Here, the effect of the enhancer methoxydiethylborane (MDEB) on the combustion promotion of kerosene/ethanol-based fuels at low temperatures was investigated, where a strategy combining combustion pathway regulation and heat release enhancement is proposed. The deformation of MDEB/kerosene/ethanol droplets induced by vigorous boiling helps destroy the stable indirect thermal contact and thus, decrease the evaporation time (∼49% maximum reduction) and shortens the ignition delay time (IDT), compared with neat kerosene/ethanol. The two-stage negative temperature coefficient behavior of IDT is effectively controlled and ultimately eliminated with the ascending of the MDEB proportion. This is due to a new channel driven by the formation of alkoxy (RO) radicals, which promotes the oxidation of MDEB/kerosene/ethanol hybrid fuels and the accompanying oxidation heat release, and subsequently, boosts the yield of active radicals, involving peroxy (ROO), hydroperoxyalkyl (QOOH) and hydroxyl (OH) radicals. The flammable temperature limit and IDT decrease from 580 °C and 1330 ms for pure 85% RP-3 kerosene/15% ethanol (K85/E15) to 115 °C and ∼ 25 ms for MDEB/K85/E15, respectively, which fulfills the low-temperature reliable and rapid start-up regardless of Leidenfrost effect. Further, the combustion behavior shows that MDEB/K85/E15 combusts completely with blue flame instead of numerous soot, which should be dominated by the self-supplying oxygen or easy oxidation characteristics of the enhancer. The findings therefore open up a new way for promoting combustion stability of kerosene/ethanol blends for aviation engines, and for pollutants control at lower temperatures.

New insight into NH3-H2 mutual inhibiting effects and dynamic regimes at low-intermediate temperatures

The hydrogen effect as a “fuel enhancer” on ammonia oxidation features is a relevant topic for ammonia-based energy conversion systems. For the most, scientific literature is focused on high temperature ammonia-hydrogen oxidation chemistry, whereas few works focus on low-intermediate temperatures (900–1350 K), relevant for non-conventional low-temperature combustion processes. Recently, low-intermediate and the shift to high-temperature ammonia oxidation chemistry has been characterized through experimental tests in a Jet Stirred Flow Reactor (JSFR) by the same authors, with the identification of thermo-kinetic instabilities. In addition, the ammonia effect on hydrogen oxidation chemistry has been addressed through a mutual inhibiting interaction for low-intermediate temperatures.Given this background, this work investigates the hydrogen effects on ammonia oxidation and thermo-kinetic instabilities from low-intermediate to high temperatures in a JSFR, parametrically varying the H2 inlet concentration. Maps of combustion behaviours (Tin- ϕ) are then drawn up, on the basis of experimental evidences, in the range 1200K<Tin<1350 K, and 0.2 <ϕ<1.2. Results show H2 only moderately enhances the reactivity of the system for the investigated conditions. Consequently, dynamic regime areas in Tin-ϕ maps are slightly shifted towards lower Tin and restricted to a narrower ϕ range.Numerical simulations were able to predict the main NH3/H2 oxidation features, albeit low-intermediate temperature oxidation chemistry description is very mechanism-dependent. Nonetheless, the H2-NH3 mutual inhibiting interaction oxidation chemistry is congruently addressed: NH3 acts as OH radical scavenger, thus partially inhibiting the direct H2 oxidation, whereas H2 re-coverts back NH2 radicals to NH3, through the reaction NH2+H2=NH3+H. The same reaction produces the sole H radicals able to feed the high-temperature branching reaction of the H2/O2 sub-system. Same concluding remarks on the NH3/NH3--H2 oxidation chemistry open issues are then reported.

Combined effects of electric supercharger and LP-EGR on performance of turbocharged engine

LP-EGR and turbocharging can improve thermal efficiency, but its specific mechanism needs to be further studied from the energy conversion. The fast response characteristic of electric supercharger can make up for turbine lag. The effect of electric supercharger on the steady state and transient characteristics of a LP-EGR turbocharged engine are investigated. Under the condition of 1500 r·min−1 and 14 bar, the electric supercharger can increase the EGR rate from 5% to 30%. The introduction of exhaust gas can increase the intake volume and reduce the pumping losses. The increase of turbocharger power indicates the reduction of exhaust energy losses. The decrease of combustion temperature optimizes the combustion phase, increases the constant volume degree of combustion and reduces the heat transfer losses. The application of EGR improves the fuel economy by 5%. For emission, low temperature combustion and low oxygen content reduce NOx emission by 80%. Incomplete combustion losses increase THC emission. CO emission is related to excess-air coefficient, so it is basically unchanged. The electric supercharger can speed up the establishment of the intake manifold pressure. The power transient response time is shortened by 72%. The advance of torque platform improves the power performance of engine at low speed.

Multiple fuel injection strategy for premixed charge compression ignition combustion engine using biodiesel blends

In the last decade, advanced combustion techniques of the low-temperature combustion (LTC) family have attracted researchers because of their excellent emission characteristics; however, combustion control remains the main issue for the LTC modes. The objective of this study was to explore premixed charge compression ignition (PCCI) combustion mode using a double pilot injection (DPI; pilot-pilot-main) strategy to achieve superior combustion control and to tackle the soot-oxides of nitrogen (NOx) trade-off. Experiments were carried out in a single-cylinder research engine fueled with 20% v/v biodiesel blended with mineral diesel (B20) and 40% v/v biodiesel blended with mineral diesel (B40) vis-à-vis baseline mineral diesel. Engine speed and rate of fuel-mass injected were maintained constant at 1500 rpm and 0.6 kg/h mineral diesel equivalent, respectively. Pilot injection timings (at 45° and 35° before top dead center (bTDC)) and fuel quantities were fixed, while three fuel injection pressures (FIPs) and four different start of the main injection (SoMI) timings were investigated in this study. Results showed that multiple pilot injections resulted in a stable PCCI combustion mode, making it suitable for higher engine loads. For all test fuels, advancing SoMI timings led to relatively lesser knocking; however, engine performance characteristics degraded at advanced SoMI timings. B40 exhibited relatively superior engine performance among different test fuels at lower FIP; however, the difference in engine performance was insignificant at higher FIPs. Fuel injection parameters showed a significant effect on emissions, especially on the NOx and particulates. Advancing SoMI timing resulted in 20%–50% lower particulates emissions with a slight NOx increase; however, the differences in emissions at different SoMI timings reduced at higher FIPs. Somewhat higher particulates from biodiesel blends were a critical observation of this study, which was more dominant at advanced SoMI timings. Qualitative correlation between NOx-total particulate mass (TPM) was another critical analysis, which exhibited the relative importance of different fuel injection parameters for other alternative fuels. Overall, B20 at 700 bar FIP and 20° SoMI timing emerged as the most promising proposition with some penalty in CO emission.

A parametric modeling study of thermal barrier coatings in low-temperature combustion engines

• Low-temperature combustions are more favorable with the thick coating configurations. • In-cylinder thick thermal barrier coating improves the indicated thermal efficiency by 4.6%. • Thick thermal barrier coating increases the volumetric efficiency due to the lower IVC temperature. • Thick thermal barrier coating increases the exhaust enthalpy and reduces intake temperature requirement. In-cylinder thermal barrier coatings (TBCs) reduce heat transfer losses and increase thermal efficiency. It has been shown that thick TBCs negatively impact the performance of conventional combustion modes by degrading volumetric efficiency and increasing the propensity for end-gas knock. Low-temperature combustion (LTC) is an advanced combustion strategy that offers high efficiencies and low emissions. Due to the nature of kinetics-driven autoignition, LTC is fundamentally different from the conventional combustion modes, where the benefits and tradeoffs of thick TBCs need to be re-evaluated. Previous experimental studies showed the feasibility and the efficiency gains associated with a 2 mm thick TBC applied to the piston surface, as well as the reduction in the required intake temperature with no observable deterioration on the high load limit. However, the effects of TBCs and their independent thermophysical properties on LTC have not been systematically explored. It is necessary to perform a comprehensive study on the effects of TBC on LTCs from a fundamental thermodynamic perspective, which serves as the motivation for the current study. This study couples a 0D engine thermodynamic model to a 1D transient heat transfer model of the coating and piston. The model was first validated against the metal piston baseline, followed by validation against experimental data of the TBC cases at different engine loads. With confidence established in the model’s fidelity, three parameters are investigated independently: thermal conductivity ( k ), coating thickness, and volumetric heat capacity ( s ). The results revealed that the volumetric efficiency actually increases by 7.4 percentage points with a thicker coating due to a reduction in heat transfer during the compression stroke, which allows for a lower intake temperature requirement to reach autoignition. However, there is a thickness limit before the intake temperature becomes impractically low. The results show that elevating surface temperature is directly proportional to higher efficiency. Therefore, the optimal coating configuration for kinetically-controlled LTC is a combination of the lowest k , thickest coating before reaching the limit, and the lowest s , where the low k and high thickness contribute the most thermal efficiency gains (4.1 percentage points) and increased exhaust enthalpy (5.7%).

Fuel reactivity controlled compression ignition engine and potential strategies to extend the engine operating range: A comprehensive review

• Key features exploration for future act PCCI/RCCI/DDFS engine. • We research the issues and challenges in medium and high engine load operating range. • The impact of direct dual fuel stratification techniques on combustion stability is evaluated. • A review of the oxidation mechanism of both high and low reactive fuels have achieved. • Successful implementation of duel fuels potentially leads to tuning charge stratification. • Engine phasing achieved by DDFS with direct injections of high and low reactivity fuel. The objective of this study is to explore various strategies i.e. reactivity stratification, thermal stratification, injection timing, and exhaust gas recirculation as key factors for prolonging the PCCI/RCCI/DDFS engine operational spectrum and suppressing the ringing intensity. Since most of the current motivating strategies can be lumped into the category of premixed Low-Temperature-Combustion (LTC), the potential of this paper is to demonstrate the robustness of LTC in addressing several challenges related to premixed charge compression ignition engine, viz., lack of phasing regulation of combustion at heavy engine loads and excessive pressure rises. With a premixed preparation strategy, however, emission species are seen to decrease, yet the challenges of pre-combustion charge preparation are present. This can deduct a noticeable extent of fuel energy. To avoid the steep trend of pressure rise problem that restricts LTC engines with their operating range, higher levels of fuel blending and regulating the timing of auto-ignition are used. This review demonstrates the ongoing progress in premixed LTC techniques aim to control of nitrogen oxides (NO x ), reduction of particulate matter (PM), and hydrocarbon (HC). In comparison to normal LTC operation, the duel fuel charge stratification might increase indicated thermal efficiency (ITE) by 5% to 7% across the survey. For various charge compositions, tests were made in homogeneous charge compression ignition (HCCI) and reactivity controlled compression ignition (RCCI). These results are provided and analyzed in comprehensive detail, with extensive correlations to model predictions and a thorough kinetic analysis. Furthermore, injection strategies were reviewed to accomplish highly efficient preparation of the combustion charge, reduce the combustion environment temperature, and enhance premixing. By highlighting relevant components of this rich and quickly growing field of knowledge, this study aims to give an insight to and summary of current studies on LTC combustion. As a result, this document serves as a fundamental collection of information and recommendations on the current state of combustion research on various fuels.

A review on butanol properties, production and its application in internal combustion engines

The automotive vehicle markets are full of the application of internal combustion engines (ICE). Although, there is a very small share of battery operated engines that exist but it is in the developing stage and suffering from some challenges. Most vehicles are either SI engine or CI engine driven vehicles. The conventional fossil fuels petrol and diesel are the lifeline of these engines. The growing demand, increasing prices and harmful effects from the application of these fuels has raised concern over the use of it. Butanol is an alcohol based bio-fuel that presents the potential to overcome the negative aspects of traditional fuels and can serve the purpose of clean, efficient and environmentally friendly renewable alternative fuel. This review article includes the properties of butanol, its superiority over the other alcohol fuels like methanol and ethanol, its production method especially the ABE fermentation process and, its application and implementation in ICE as a neat fuel and as a blend. The neat butanol or its blend with petrol or diesel shows some advantages but to get more benefits from the application of butanol as engine fuel it needs to be used with innovative combustion methods. The low temperature combustion (LTC) and their different forms like homogeneous charge compression ignition (HCCI) and reactivity controlled compression ignition (RCCI) are the advanced combustion techniques in which butanol fueled operation offers more benefits as compared to butanol fueled SI and CI engines. In recent years, the potential of n-butanol (an isomer of butanol) is being investigated extensively in HCCI and RCCI engines as it shows excellent features like a great reduction in NOx and smoke emissions and higher thermal efficiency.

Effects of Non-Equilibrium Plasma and Spark Discharge on Low-Temperature Combustion in Lean Propane/Air Mixtures

Effects of Non-Equilibrium Plasma and Spark Discharge on Low-Temperature Combustion in Lean Propane/Air Mixtures

The High Activity of Mn2+-Rich Co-Mn-O Solid Solution Catalyst for Low-Temperature Methane Combustion

The High Activity of Mn2+-Rich Co-Mn-O Solid Solution Catalyst for Low-Temperature Methane Combustion

Study on methanol premixed coupled with EGR to achieve ultra-low emissions in diesel engine

In this paper, an experimental investigation on achieving ultra-low emissions in diesel engine was carried out using intake premixed methanol and EGR technology. The influence of EGR introduction method on combustion and performances were studied comprehensively. The results show that ultra-low NOx (&lt;0.4g/kWh) and PM (&lt;10mg/kWh) emissions can be achieved simultaneously in diesel methanol dual fuel (DMDF) highly premixed low-temperature combustion mode. Compared with low-pressure EGR (LP-EGR), the excess air coefficients under high-pressure EGR (HP-EGR) drops more significantly. At the same EGR rate, the in-cylinder mean temperature and equivalent of mixture are higher under HP-EGR conditions, which results in higher combustion efficiency, lower CO and THC emissions. The maximum brake thermal efficiency of high-pressure EGR is 9.6% higher than that of low-pressure EGR.

Assessment of The Impact of Multiple Injection Strategies on Combustion Noise, Smoke and Performance Characteristics of a CRDI Heavy Diesel Engine

This experimental research paper presents the impact of 5 different multiple injection strategies as 2-double comprising pilot-Main (pM), Main-after (Ma), 2-triple comprising pilot-Main-after (pMa), early-pilot-Main (epM) and quadruple comprising early-pilot-Main-after (epMa) in comparison with single injection on combustion noise (CN), Brake Specific Fuel Consumption (BSFC), Torque, Brake Thermal Efficiency (BTE) and Smoke emissions. The experimental evaluation was carried out on a 6-cylinder inline CRDI (Common rail Direct Injection) diesel engine in low temperature combustion (LTC) regime with high EGR of 45%, and fixed main injection Crank Angle (CA) using conventional diesel (BS-IV) fuel at full load and 8 speeds (low to high). The comprehensive study revealed that quadruple (epMa) injection strategy is superior in providing optimum results in comparison to other 4 multiple injection strategies in line to single injection. This strategy displayed better BSFC at medium to high speeds zone inline to reduce of combustion noise (radiated) level especially at low speeds around 2 dBA. The epMa exhibited the 2nd best smoke/soot concentration whereas pMa injection scheduling is best in lower smoke/soot generation. The epMa was found to be an optimum in torque performance though epM showed best torque performance in low to medium speed zone. The epMa showed the best BTE than all other. This work indicates the potentiality and further scope to achieve better performance and emissions simultaneously with quadruple injection strategy by parametric optimization of injection parameters.