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Ethanol fuel is considered a renewable energy source with a lower global warming potential than gasoline. The purpose of this paper is to analyze the emissions and performance of gasoline-ethanol blends in SI engines under various conditions. A computerized 4s, 1cyl, VCR spark ignition engine is used for the tests to measure the performance of Gasoline-Ethanol (GE) blends in particular E-10 (10% ethanol, 90% gasoline). For measuring exhaust emissions as well as performance, regular gasoline fuel is used for the additional tests. Engine performance using ethanol-gasoline blended fuel has been evaluated at different working conditions: 1200-1800 rpm, AFR 0.9, STs 300, CR10:1. When vehicles running on ethanol-gasoline blend indicated a decrease in the amounts of HC, NOx, and CO exhaust gases while 3.9% increase in CO2 emissions as compared to unleaded gasoline fuel. Furthermore, it has been shown that the brake power, torque, specific fuel consumption increases when a Gasoline-Ethanol (GE) blend is used over regular gasoline fuel. [ABSTRACT FROM AUTHOR]

This paper deals with the performance improvement of a turbocharged spark ignition (SI) engine redesigned by adopting a refined 1D model and a rule-based (RB) calibration strategy. The new SI engine operates without the throttle valve and combines an early intake valve strategy with a two-stage compression ratio device. The resulting SI unit represents a promising short-term technical solution and it is also suitable as a flexible fuel engine.In a first phase, the engine model is validated with the experiments in the original configuration, and then it is virtually modified to obtain the redesigned solution. In this redesign process, the effects of the variations of engine geometry and valve strategy on combustion and performance are considered by phenomenological in-cylinder sub-models. Afterwards, the RB strategy is implemented into the re-designed engine model and assessed by comparing the results with the ones of an advanced calibration approach, based on an optimization with genetic algorithm performed by coupling the 1D model with an optimizer.The RB method replicates with acceptable accuracy the numerical trends of performance and control parameters of the SI engine coming from the optimizer. Once the capability is verified, the RB strategy is adopted to compute the steady operating map of the redesigned engine, with significantly less effort than an optimization. The map provides noticeable benefits in terms of full load torque, fuel consumption at medium-to-low loads and a slight extension of the minimum fuel consumption region. The combustion stability is maintained at acceptable levels, although it is improvable at very low loads and speeds. The presented methodology has a general validity for conventional SI engines and can be efficiently exploited to support the redesign stage of SI units for improved performance, with reduced computational effort. It also offers a method to rapidly compute the operating map of SI engines for subsequent on-vehicle analyses.

Evaluation of the effects of Gasoline-Methanol (GM) fuel blends on SI engine perfor-mance and emissions analysis was the aim of this research. Engine performance was ana-lyzed using M15 fuel blends at Wide Open Throttle (WOT) and various speed conditions between 1200 to 1800 rpm. A computerized 4s, 1cyl, VCR petrol engine test setup was used for the experimental work. The results found that the BSFC of M15 blends in-creased as much as regular gasoline for all engine speeds at full load. Exhaust emissions, including CO, HC, CO2, and NOx, are found to be minimized while engine torque and brake power (BP) is less than regular gasoline. This research recommends a methanol-gasoline blend can be an effective alternative for gasoline in transportation engines with-out requiring hardware modifications or causing major environmental harm. It found that the M15 fuel blend was appropriate for both increasing engine performance and reducing emissions. [ABSTRACT FROM AUTHOR]

In the current study, an onboard dry cell electrolyzer was built to produce an oxyhydrogen (HHO) flow rate of 0.5 L/min by water electrolysis. The objective is to show the impact of oxyhydrogen introduction on engine exhaust gases, combustion characteristics, and engine performance related to gasoline. The experiments were carried out in a petrol engine at a fixed engine speed of 3000 rpm and variable engine loading. When comparing HHO gasoline dual fuel to standard gasoline fuel, the maximum improvements in volumetric efficiency, thermal efficiency and air-fuel ratio were determined as 7.5%, 8% and 11%, respectively. In the case of HHO addition, the highest reductions in specific fuel consumption and exhaust gas temperature were 9% and 6.5%, respectively, compared with conventional gasoline fuel. The highest reduction in CO, HC, NOx, and CO 2 concentrations was observed as 18%, 9%, 15%, and 11%, respectively, for HHO-gasoline dual-fuel mode compared to gasoline fuel. The peak cylinder pressure and HRR improvements were 1.5% and 4.5%, respectively, at 100% engine load. Oxyhydrogen gas is highly recommended as a substitute fuel since it significantly enhances engine performance and combustion characteristics as well as reducing exhaust pollutants. • An on-board dry cell electrolyzer was used with an HHO flow rate of 0.5 L/min. • Experiments were carried out in SI engine at 3000 rpm and variable engine loading. • Maximum improvement in BTE was 8% about the reduction in BSFC was 9%. • HHO-gasoline dual-fuel mode found reduction in CO, HC, NOx, and CO 2 emission. [ABSTRACT FROM AUTHOR]

Renewable resources are minimal throughout the world and considerable research work has been carried out to develop fossil-based options. Aim of the research work is to evaluate performance and engine exhaust emissions of varying blends at different conditions in engine. The experiments are conducted to analyze the performance of three distinct gasoline-alcohol fuel mixtures EM25 (10 percent ethanol-15 percent methanol-75 percent gasoline) in a computerized 1-cylinder, 4-stroke, VCR SI engine. The additional tests are conducted using regular gasoline fuel to compare performance and engine exhaust emissions. The engine performance using mixed fuel of ethanol-methanol-gasoline (GEM) has been evaluated under the various operating conditions in the range of 1200 to 1800 rpm, Spark Timings (ST's) 100, Air Fuel Ratio 0.9 at constant Compression Ratio (CR) 10:1. When the vehicles operated with ethanol-methanol-gasoline mixtures then it has found that there is the reduction in HC, CO2, CO exhaust gases contents while 14% increments in NOx emission as compared with regular gasoline fuel. It is also observed that the brake power/brake torque is decreased when operated on ethanol-methanol-gasoline fuels as compared to pure gasoline. However, it has been revealed that BSFC is enhanced in comparison to regular gasoline. [ABSTRACT FROM AUTHOR]

The use of alternative fuels, such as alcohol-based fuels, has received a significant attention as a substitute for gasoline in spark-ignition engine. This study examines the influence of methanol-gasoline blends on both performance and emissions of a single-cylinder, spark-ignition engine. The engine is tested under full load conditions and at speeds range varying from 1000 to 3000 rpm. Four fuel blends labeled M0, M10, M20, and M40, were used, where the numbers represent the percentage by volume of methanol in the blend. It has been shown that the addition of methanol improves the power output and the torque of the engine. The highest improvement observed in engine power is 37% for M20 blend. Specific fuel consumption and thermal efficiency have also been improved with increasing methanol blending ratio. M40 showed a decrease in fuel consumption by 38% and an enhancement in thermal efficiency by 95%, at medium speed, compared to pure gasoline. Additionally, the results have shown significant reduction in CO and CO2 emissions, more particularly at low engine speeds (below 2000 rpm), where the addition of methanol (up to M40) has led to reducing CO emission with up to 70% compared to that of M0. However, NOx emissions increased with increasing methanol blending ratio. The highest increase in NOx levels was given by M40 by about 60% at low engine speed. [ABSTRACT FROM AUTHOR]

There has been extensive research on efficient energy conversion systems which also includes turbocharging the automotive SI engine. This research focuses on comparing the thermodynamic aspects of the turbine at different boost pressures at maximum engine torque and speed regions. A naturally aspirated CNG SI engine developing 15.5 kW at 3400 rpm was converted to a turbocharged LPG engine at the compression ratio of 8.5:1. The turbine performance was evaluated using ANSYS CFX numerical simulation tool and results were validated. The simulation study reveals that 1.3 bar boost pressure has a higher enthalpy generation and also has minimal Mach number than 1.5 bar signifying the effects of exhaust blowdown. Further, the experimental study was carried out at different boost pressures. The results show that at 1.3 bar, the turbine efficiency was higher with reduced heat transfer rate to the compressor which was due to reduced friction work compared to 1.5 bar which altogether improved the engine performance. This is also evident from the minimal COV of IMEP for 1.3 bar. On the whole, the turbine exhibited better performance for 1.3 bar and resulted in reduced thermal loading. [ABSTRACT FROM AUTHOR]

This study focused on the performance and exhaust emissions of gasoline engines using gasoline-like fuel (GLF) produced from hard-resin of Yang (HY) by the fast pyrolysis process in semi-continuous reactors at pyrolysis temperature of 500 °C. Bio-oil products obtained from the process were distilled into heavy fuel at 200–350 °C and light fuel at 25–200 °C. HY (100%wt) generated 20.5%wt of light fuel and 30.8%wt of heavy fuel with 35.0%wt of gas and 13.7%wt of waste obtained. Light fuel as well as GLF and gasoline were tested for distillation, density, viscosity, heating value, flash point and silver strip corrosion under ASTM and also for the effect of GLF on performance and exhaust emissions of spark-ignition (SI) engines for a four-stroke single cylinder and fuel mixing system with carburetor. Positive results were shown for performance of brake torque, brake power and brake thermal efficiency. Findings revealed that brake specific fuel consumption was lower compared to gasoline. Carbon monoxide (CO) and hydrocarbon (HC) from engine exhaust were lower than gasoline with carbon dioxide (CO 2) and nitrogen oxides (NO x) higher. • HY is a raw material with high LHV and volatile content for production as fuel. • GLF from HY can be used with single cylinder SI engines as well as gasoline. • Brake specific fuel consumption of test engines using GLF was less than gasoline. • HC and CO emissions of GLF were lower than gasoline. [ABSTRACT FROM AUTHOR]

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the literature mainly obtained in the CFR engine. Particular attention was paid to determine the lowest possible load limit when the engine is supplied with pure ammonia or a small amount of H2, depending on engine speed, in order to highlight the limitation during cold start conditions. It can be concluded that this engine can run stably in most of these operating conditions with less than 10% H2 (of the total fuel volume) added to NH3. Measurements of exhaust pollutants, and in particular NOx, have made it possible to evaluate the possibility of diluting the intake gases and its limitation during combustion with pure H2 under slightly supercharged conditions. In conclusion, the 10% dilution limit allows a reduction of up to 40% in NOx while guaranteeing stable operation.

Abstract: Strategy of lean burn for reducing fuel consumption and emissions can be achieved by incorporating swirling motion in the incoming fluid entering the cylinder of the engine. In this backdrop, the application of shrouded intake valves gets the upper hand over the conventional poppet valve because of their capacity of producing intake-generated swirl flow. In the existing literature, a modified shrouded intake valve capable of producing significant amount of swirl with relatively smaller restriction to the incoming fluid has been reported. But, no work has been done to determine the effect of using modified shrouded intake valve in the emissions and performance of an SI engine. Thus, the effect of using the modified shrouded intake valve on the emissions and performance of an SI engine is studied and compared with that of poppet intake valve and 100°, 140°, and 180° shrouded intake valves. From the study, it is seen that the engine with modified shrouded intake valve produces lowest hydrocarbon and carbon monoxide emissions for maximum power condition, whereas the brake power, brake specific fuel consumption, and NOx emissions of the engine are quite close to the engine using poppet intake valve which is the best performing valve-engine combination for the same. For minimum brake specific fuel consumption condition, the engine with modified shrouded intake valve produces the highest brake power with the lowest brake specific fuel consumption, whereas the hydrocarbon and carbon monoxide emissions of the engine are similar to the engine using 180° shrouded intake valve which is the best performing valve-engine combination for the same.Graphical abstract: [ABSTRACT FROM AUTHOR]

In this investigation, performance and emission characteristics for enhancing LPG, hydrogen, and hydroxy with E20 were evaluated for the understanding of which fuel combination performs better in a gasoline engine. In the upper sequence, hydroxy-hydrogen-LPG could perform best in terms of brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC). The induction of gaseous fuel improves CO, CO2, and HC emission but increases the NOx emission. More concisely, the enhancement of hydroxy with E20 shows the best engine performance for highest BTE while lowest BSFC as well as lowest exhaust emissions (CO, HC, except NOx). [ABSTRACT FROM AUTHOR]

Bio-n-butanol has attracted great attention as a potential alternative fuel in internal combustion engines (ICEs) due to its favorable physicochemical properties. However, the main issue impeding the use of bio-butanol in ICEs is its relatively high cost and energy consumption of dehydration and recovery processes in acetone-n-butanol-ethanol (ABE) or isopropanol-n-butanol-ethanol (IBE) fermentation technologies. Some researchers have proposed to use intermediate fermentation product, i.e. water-containing ABE or IBE, for clean combustion. Therefore, an experimental evaluation of spark-ignition (SI) engine fueled with water-containing IBE-gasoline blends was carried out in this study. Effects of IBE and water addition on combustion, performance, and emissions characteristics were first investigated at stoichiometric condition. Then, a “drop-in” fuel test was performed, i.e. IBE9W1 (9 vol.% IBE, 1 vol.% water and 90 vol.% gasoline) was compared with pure gasoline under various engine loads (3 and 5 bar BMEP) and equivalence ratios (Φ = 0.83–1.25). It was found that IBE9W1 showed a higher brake thermal efficiency, and a lower CO, NO x and BTX (benzene, toluene and xylene) emissions. The results indicate that water-containing IBE could be used as a fuel candidate in SI engine due to its eco-friendly production method and potential to improve energy efficiency and reduce emission pollutants. [ABSTRACT FROM AUTHOR]

Internal combustion engines that are widely used as a power source in passenger and freight transport, individual transport vehicles, agricultural sector, fixed and mobile generators, are dependent on fossil fuels, especially oil. However, decrease in the oil reserves and environmental problems such as the global warming have compelled researchers to search for alternative fuels for internal combustion engines. In this study, the effects of the use of gasoline and acetylene mixtures on the overall performance of a spark ignition (SI) engine have been experimentally investigated. Experiments have been carried out on a four-stroke, four-cylinder, water-cooled SI engine and at stoichiometric conditions. Acetylene flow rates were fixed at 500 g/h and 1000 g/h in these experiments. The performance and emission parameters were studied by changing the load from 25% to the full load. The maximum acetylene content of the gasoline-acetylene mixture was 54% at 25% load, while this rate was 22.4% at the full load. Acetylene induction resulted in lower thermal efficiency at almost all loads. A decrease in hydrocarbon emissions was observed at all engine loads while NO emissions increased at low loads when compared to that of gasoline. [ABSTRACT FROM AUTHOR]

The performance and emission characteristics of LPG fuelled SI engine is determined by efficient combustion. This depends on the in-cylinder motion of intake homogenous charge generated by combustion chamber geometry. The inherent, unsteady, turbulent motion of the mixture helps in flame propagation which in turn enhances the combustion rate. Compression ratio, charge squish velocity and turbulent kinetic energy are responsible for stable combustion and laminar flame propagation. The in-cylinder charge motion is generally described by swirl, squish, tumble and turbulence which have a vital role on air-fuel mixing and combustion. The piston geometry helps in aiding in-cylinder motion for reducing fuel consumption and enhancing the combustion parameters. In particular, piston squish area in combustion chamber geometry has a major influence in charge motion inside the combustion chamber. The effect of piston squish area on charge motion was studied by CFD using STAR-CD with 25%, 30%, 35% and 40% squish areas to optimize piston crown geometry. Experiments were also conducted with above squish area pistons at a compression ratio of 10:1 to validate the CFD study. It was found that 30% piston squish area improved the performance, combustion characteristics and reduced the emission with LPG fuelled lean burn SI engine. [ABSTRACT FROM AUTHOR]

The experimental investigation of 2nd generation bioethanol derived from EFB of oil-palm blended with gasoline for 10, 20, 25% by volume and pure gasoline were conducted on performance and exhaust emission tests of SI engine. A four stroke, four cylinders, programmed fuel injection (PGMFI), 16 valves variable valve timing and electronic lift control (VTEC), single overhead camshaft (SOHC), and 1,497 cm3 SI engine (Honda/L15A) was used in this investigation. Engine performance test was carried out for brake torque, power, and fuel consumption. The exhaust emission was analyzed for carbon monoxide (CO) and hydrocarbon (HC). The engine was operated on speed range from1,500 until 4,500 rev/min with 85% throttle opening position. The results showed that the highest brake torque of bioethanol blends achieved by 10% bioethanol content at 3,000 to 4,500 rpm, the brake power was greater than pure gasoline at 3,500 to 4,500 rpm for 10% bioethanol, and bioethanol-gasoline blends of 10 and 20% resulted greater bsfc than pure gasoline at low speed from 1,500 to 3,500 rpm. The trend of CO and HC emissions tended to decrease when the engine speed increased.

Acetone is widely recognized as a major organic solvent and also a basic ingredient for varnishes and paints. In comparison with ethanol, acetone has more attractive properties as a potential alternative fuel such as its higher energy density, heating value, and volatility. However, the water content in acetone production would lead to a high cost for dehydration, and may prohibit acetone from being widely used in internal combustion engines. This has prompted research on using water containing acetone as a potential alternative fuel. In this study, various acetone-gasoline blends such as A10 (10 vol% acetone and 90 vol% gasoline by volume), A20 (20 vol% acetone and 80 vol% gasoline by volume), A19.5W0.5 (19.5 vol% acetone and 0.5 vol% water and 80 vol% gasoline) and A19W1 (19 vol% acetone and 1 vol% water and 80 vol% gasoline) were used as fuels in a port-fuel injection (PFI) spark ignition (SI) engine. The performance of test fuels was compared with that of G100 (gasoline) under various equivalence ratios ( Φ ) from 0.83 to 1.25 and at engine loads of 3 and 5 bar BMEP. In addition, aromatic compound emissions such as benzene, toluene, ethylbenzene, xylene (BTEX) were also measured by gas chromatograph (GC) with mass spectrometer and flame ionization detector. The results showed that A19W1 generally had a more advanced combustion phasing, higher brake thermal efficiency, and lower carbon monoxide (CO), nitrogen oxide (NO x ) and BTEX than those of other test fuels. Therefore, water containing acetone-gasoline blends could be used as a good alternative fuel due to the improvement of engine performance and reduction of emissions. [ABSTRACT FROM AUTHOR]

Much research is ongoing to find suitable alternate fuels in order to reduce the exhaust emission levels without deteriorating the basic performance characteristics of conventional spark-ignited (SI) engines. One of the methods to achieve the above problem is the use of alcohols as full supplement fuels to normal gasoline. At the same time, many related research studies have shown that the use of alcohols has a negative impact on some basic engine performance characteristics, e.g., brake power output, etc. On the other hand, spark timing is one of the critical engine operating parameters that significantly influences the combustion mechanism inside the combustion chamber of a SI engine. Therefore, the primary objective of the present work is to investigate the effect of spark timing on the performance and emissions characteristics of a conventional, four-stroke, SI engine running under three different fuel operating modes, viz. with conventional gasoline or ethanol or butanol. The specific investigation is conducted by using an in-house, comprehensive, two-zone phenomenological model. The predictive ability of the model is tested against pertinent experimental data and it is found that the computed results are in good agreement with the respective experimental ones. For all test cases examined herein, the results concern basic engine performance characteristics, i.e., cylinder pressure, power output, specific fuel consumption etc., as well as NO and CO emissions. The main objectives of the work were to record and evaluate the impact that spark timing has on the performance characteristics and emitted pollutants of a conventional SI engine, operating under either conventional gasoline or ethanol or butanol fuel operating modes. Moreover, it deals with the determination of an optimum combination between the type of fuel used and the spark timing, so that probable undesirable effects on engine performance characteristics would be avoided. By comparing this investigation results, it is revealed that the use of alcohols as a full substitute fuel of gasoline accompanied with an appropriate alteration of the spark timing, could be a promising solution to improving both the efficiency and environmental behavior of a light-duty, spark-ignited (SI) engine, without causing any harmful problems to the engine operational lifetime. The conclusions from the study may prove valuable for the application of this technological solution to existing conventional SI engines. [ABSTRACT FROM AUTHOR]

Alternative fuel has become very significant and has an important role to play for both spark ignition and compression ignition engines, so the need to trim down dependency on gasoline as a fuel and its economic aspects has emerged as the reason of prime importance. Various investigations carried out have primarily focused on using alternative fuel to see the diminishing effect on the fuel consumption. The aim of this review is to study and analyze the range of opportunities and future prospects of introducing blend of gasoline-ethanol, gasoline with all other alcohol derivative and subsequent alternative fuel in varying percentage ratios in the existing SI engines by diagnosing various aspects such as air-fuel ratio, operating cylinder pressure, ignition timing and compression ratio related to the performance parameters only. [ABSTRACT FROM AUTHOR]

Bio-butanol is typically produced by acetone-butanol-ethanol (ABE) fermentation, however, the recovery of bio-butanol from the ABE mixture involves high costs and energy consumption. Hence it is of interest to study the intermediate fermentation product, i.e. ABE, as a potentially alternative fuel. In this study, an experimental investigation of the performance, combustion and emission characteristics of a port fuel-injection SI engine fueled with ABE-gasoline blends was carried out. By testing different ABE-gasoline blends with varying ABE content (0 vol%, 10 vol%, 30 vol% and 60 vol% referred to as G100, ABE10, ABE30 and ABE60), ABE formulation (A:B:E of 1:8:1, 3:6:1 and 5:4:1 referred to as ABE(181), ABE(361) and ABE(541)), and water content (0.5 vol% and 1 vol% water referred to as W0.5 and W1), it was found that ABE(361)30 performed well in terms of engine performance and emissions, including brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), unburned hydrocarbons (UHC) and nitrogen oxides (NO x ) emissions. Then, ABE(361)30 was compared with conventional fuels, including E30, B30 (30 vol% ethanol or butanol blended with gasoline) and pure gasoline (G100) under various equivalence ratios and engine loads. Overall, a higher BTE (0.2–1.4%) and lower CO (1.4–4.4%), UHC (0.3–9.9%) and NO x (4.2–14.6%) emissions were observed for ABE(361)30 compared to those of G100 in some cases. Therefore, ABE could be a good alternative fuel to gasoline due to the environmentally benign manufacturing process (from non-edible biomass feedstock and without a recovery process), and the potential to improve energy efficiency and reduce pollutant emissions. [ABSTRACT FROM AUTHOR]

This study investigates the effect of using terpineol as an octane booster for gasoline fuel. Unlike ethanol, terpineol is a high energy density biofuel that is unlikely to result in increased volumetric fuel consumption when used in engines. In this study, terpineol is added to non-oxygenated FACE F gasoline (Research Octane Number = 94.5) in volumetric proportions of 10%, 20% and 30% and tested in a single cylinder spark ignited engine. The performance of terpineol blended fuels are compared against a standard oxygenated EURO V (ethanol blended) gasoline. It was determined that the addition of terpineol to FACE F gasoline enhanced the octane number of the blend, resulting in improved brake thermal efficiency and total fuel consumption. For FACE F + 30% terpineol, break thermal efficiency was improved by 12.1% over FACE F gasoline at full load for maximum brake torque operating point, and similar performance as EURO V gasoline was achieved. Due to its high energy density, total fuel consumption was reduced by 6.2% and 9.7% with 30% terpineol in the blend when compared to FACE F gasoline at low and full load conditions, respectively. Gaseous emissions such as total hydrocarbon and carbon monoxide emission were reduced by 36.8% and 22.7% for FACE F + 30% terpineol compared to FACE F gasoline at full load condition. On the other hand, nitrogen oxide and soot emissions are increased for terpineol blended FACE F gasoline when compared to FACE F and EURO V gasoline. [ABSTRACT FROM AUTHOR]

Energy sustainability and environmental issues pose greater challenges on different primary energy sectors as the global energy demand increases and it is projected to further increase with an upsurge in population. On the other hand, energy sources from conventional fossil-based fuels are depleting, forcing explorations in challenging and difficult locations. As a result, the use of alternative fuels received dramatic consideration to substitute these conventional fuels, of which natural gas took the significant share. However, the share of natural-gas vehicles in the current vehicle market is quite small, and it is estimated to be below 5%. This paper reviews the current resource scenarios including proven and potential reserves, current production, and consumption, along with the fueling infrastructure, distribution, and storage. It also provides summary of the development of fuel-injection technologies aimed to enhance the performance of gas engines. More attention was also given to natural-gas engines and their limitations. Parameters affecting the performance and combustion of compressed natural gas (CNG) in spark-ignition (SI) engines are thoroughly assessed, among which compression ratio and injection timing play major roles in the optimization of CNG-fueled engines. Furthermore, different technologies that help close the performance gap between conventional liquid-fuel and natural-gas engines and future directions of the research are presented.

Among primary alcohols, bio- n -butanol is considered as a promising alternative fuel candidate. However, relatively low production efficiency and high cost of component recovery from the acetone- n -butanol-ethanol (ABE) or isopropanol- n -butanol-ethanol (IBE) fermentation processes hinders industrial-scale production of bio- n -butanol. Hence it is of interest to study the intermediate fermentation product, i.e. ABE and IBE as a potential alternative fuels. However, for fuel applications, the IBE mixture appears to be more attractive than ABE due to more favorable properties of isopropanol over acetone, such as being less corrosive to engine part, higher energy density and octane number. In this study, an experimental investigation on the performance, combustion and emission characteristics of a port fuel-injection SI engine fueled with IBE-gasoline blends was carried out. By comparisons between IBE-gasoline blends with various IBE content (0–60 vol.% referred to as G100-IBE60) and more commonly used alternative alcohol fuels (ethanol, n -butanol and ABE)-gasoline blends, it was found that IBE30 performed well with respect to engine performance and emissions, including brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), unburned hydrocarbons (UHC) and nitrogen oxides (NO x ). Then, IBE30 was selected to be compared with G100 under various equivalence ratio ( Φ = 0.83–1) and engine load (300 and 500 kPa BMEP). Overall, higher BTE (0.04–4.3%) and lower CO (4%), UHC (15.1–20.3%) and NO x (3.3–18.6%) emissions were produced by IBE30 compared to G100. Therefore, IBE could be a good alternative fuel to gasoline due to the environmentally benign fermentation process (from non-edible biomass feedstock and without recovery process) and the potential to improve energy efficiency and reduce pollutant emissions. [ABSTRACT FROM AUTHOR]

Bio-butanol has proved to be a promising alternative fuel in recent years; it is typically produced from ABE (acetone–butanol–ethanol) fermentation from non-edible biomass feedstock. The high costs for dehydration and recovery from dilute fermentation broth have so far prohibited bio-butanol’s use in internal combustion engines. There is an interesting in studying the intermediate fermentation product, i.e. water-containing ABE as a potential fuel. However, most previous studies covered the use of water-containing ABE–diesel blends. In addition, previous studies on SI engines fueled with ABE did not consider the effect of water. Therefore, the evaluation of water-containing ABE gasoline blends in a port fuel-injected spark-ignition (SI) engine was carried out in this study. Effect of adding ABE and water into gasoline on combustion, performance and emissions characteristics was investigated by testing gasoline, ABE30, ABE85, ABE29.5W0.5 and ABE29W1 (29 vol.% ABE, 1 vol.% water and 70 vol.% gasoline). In addition, ABE29W1 was compared with gasoline under various equivalence ratios ( Φ = 0.83–1.25) and engine loads (3 and 5 bar BMEP). It was found that ABE29W1 generally had higher engine toque (3.1–8.2%) and lower CO (9.8–35.1%), UHC (27.4–78.2%) and NO x (4.1–39.4%) than those of gasoline. The study indicated that water-containing ABE could be used in SI engines as an alternative fuel with good engine performance and low emissions. [ABSTRACT FROM AUTHOR]

• Pomegranate peel oil (PPO) was derived from the rinds of pomegranate fruit and its properties were studied to use in spark ignition engine. • Gasoline-Pomegranate peel oil was prepared by blending PPO in petrol at a ratio of 10:90 by volume and tested in spark ignition engine. • To improve the performance of the PPO10 blend, tertiary butyl alcohol (TBA) was blended with PPO10 in the volumetric proportion of 5%, 10%, and 15% to form ternary blends. • The blend PPO10 + TBA15 (85 % PPO + 15 % TBA) exhibit higher BTE as compared to sole gasoline. • CO and HC emissions decrease at expense of NOx emissions for ternary blends when compared to sole gasoline. This paper reported a research work that investigated the compatibility of using pomegranate peel oil (PPO) as a substitute for gasoline in a spark-ignition engine. Initially, fuel characterization was performed for the PPO biofuel, and a blend was prepared by blending PPO in gasoline at a ratio of 10:90 by volume. Then, fuel properties were measured for the gasoline, PPO, and its blend. Subsequently, engine experiments were conducted for the blend at different load conditions with constant speed, and the performance, combustion, and emission results of the blend were compared with that of sole gasoline. By analyzing the results, it was found that the brake thermal efficiency of the 10% PPO blended gasoline was reduced by 1.2%, 0.6%, and 1%, at low load, mid load, and full load, respectively, when compared to sole gasoline. Whereas the HC and CO emission of the blend was higher by about 11.7% and 8.3%, respectively, at full load, when compared to that of gasoline. With an intent to improve the performance of the PPO blend, tertiary butyl alcohol (TBA) was blended with the 10% PPO blended gasoline in the volumetric proportion of 5%, 10%, and 15% to form ternary blends. The experimental study revealed that the performance of the PPO blend was enhanced significantly with increasing TBA proportion in the blend. The PPO blend with 15% TBA exhibited the highest BTE of 25.1%, which was 1.6% higher than gasoline at full load. The same blend resulted in the HC and CO emissions that were 9.2% and 9.6% lesser than gasoline, respectively, whereas NO emission was 7.6% higher than gasoline, at full load condition. The combustion analysis revealed that the start of combustion was delayed, with peak pressure and heat release rate being the maximum for ternary blends. From this investigation, it can be concluded that the sole gasoline can be replaced by the ternary blend as fuel for SI engine operation without requiring any major engine modification. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to evaluate the performance and emission of spark ignition (SI) engine fuelled with CNG at low and high load condition. This study is the series activity of research, design and development of conversion kit for gas fuelled vehicle in the author laboratory. The SI engine that used in this study is Honda L15A, four cylinders, 1,497 cm 3 using electronic control unit. Three different fuel system namely standard gasoline fuel system, commercially CNG conversion kit and proposed CNG conversion kit designed by Research Centre for Electrical Power and Mechatronics–Indonesian Institute of Sciences, all of them utilized with fuel injection system and electronic control unit were used in this study. The test was conducted on the 25% and 80% throttle opening position with engine speed over 4,800 rpm. The results show that the maximum brake power at 25% throttle opening position of SI engine using commercially CNG conversion kit (19.00 kW) is almost same with SI engine using proposed CNG conversion kit (19.68 kW), while for 80% throttle opening position the maximum brake power of SI engine using proposed CNG conversion kit (38.67 kW) is higher than commercially CNG conversion kit (34.29 kW). The emission of CO and HC at 80% throttle opening position is lower than at 25% throttle opening position for both of SI engine using commercially and proposed CNG conversion kit. [ABSTRACT FROM AUTHOR]

As global energy demand rises, natural gas (NG) plays an important strategic role in energy supply. Natural gas is the cleanest fossil fuel that has been investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. This paper reviews the research on the effects of natural gas composition on combustion and emission characteristics of natural gas fueled internal combustion engines (ICEs) and reports the most achievements obtained by researchers in this field. It has been reported that the engine performance and emission are greatly affected by varying compositions of natural gas. The most important NG fuel property is the Wobbe number (WN). Generally, it was agreed by researchers that the fuels with higher hydrocarbons, higher WN, and higher energy content exhibited better fuel economy and carbon dioxide (CO2) emissions. Nitrogen oxides (NOx) emissions were also increased for gases with higher levels of higher WN, while total hydrocarbons (THCs), carbon monoxide (CO), showed some reductions for these gases. On the other hand, particulate matter (PM) emissions did not show any fuel effects. Moreover, adding of small fractions of higher alkanes, such as ethane and propane, significantly improved ignition qualities of natural gas engines. The results presented provide a good insight for researchers to pursue their future research on natural gas fueled ICEs. [ABSTRACT FROM AUTHOR]

Highlights: [•] CFD modeling the combustion of different alternative fuels in SI engine. [•] 10% of EGR is the most desirable amount from the viewpoint of emissions and power. [•] EGR affects on methane fuel more than others. [•] Supercharging has the most noticeable effect on gasoline fuel and the least on hydrogen fuel. [Copyright &y& Elsevier]

The experimental investigation of 2nd generation bioethanol derived from EFB of oil-palm blended with gasoline for 10, 20, 25% by volume and pure gasoline were conducted on performance and exhaust emission tests of SI engine. A four stroke, four cylinders, programmed fuel injection (PGMFI), 16 valves variable valve timing and electronic lift control (VTEC), single overhead camshaft (SOHC), and 1,497 cm3 SI engine (Honda/L15A) was used in this investigation. Engine performance test was carried out for brake torque, power, and fuel consumption. The exhaust emission was analyzed for carbon monoxide (CO) and hydrocarbon (HC). The engine was operated on speed range from1,500 until 4,500 rev/min with 85% throttle opening position. The results showed that the highest brake torque of bioethanol blends achieved by 10% bioethanol content at 3,000 to 4,500 rpm, the brake power was greater than pure gasoline at 3,500 to 4,500 rpm for 10% bioethanol, and bioethanol-gasoline blends of 10 and 20% resulted greater bsfc than pure gasoline at low speed from 1,500 to 3,500 rpm. The trend of CO and HC emissions tended to decrease when the engine speed increased. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the effects of ethanol–gasoline (E5, E10) and methanol–gasoline (M5, M10) fuel blends on the performance and combustion characteristics of a spark ignition (SI) engine were investigated. In the experiments, a vehicle having a four-cylinder, four-stroke, multi-point injection system SI engine was used. The tests were performed on a chassis dynamometer while running the vehicle at two different vehicle speeds (80km/h and 100km/h), and four different wheel powers (5, 10, 15, and 20kW). The results obtained from the use of alcohol–gasoline fuel blends were compared to those of gasoline fuel. The results indicated that when alcohol–gasoline fuel blends were used, the brake specific fuel consumption increased; cylinder gas pressure started to rise later than gasoline fuel. Almost in the all test conditions, the lowest peak heat release rate was obtained from the gasoline fuel use. [Copyright &y& Elsevier]

Abstract: The strict regulation of environmental laws, the price of oil and its restricted resources, has made engine manufacturers use other energy resources instead of oil and its products. Despite the fact that nowadays alternative fuels are not currently widely used in vehicular applications, using these kinds of fuels will be definitely inevitable in the future. In this paper, a computer code is developed in Matlab environment and then its results are validated with experimental data. This simulated engine model could be used as an powerful tool to investigate the performance and emission of a given SI engine fueled by alternative fuels including hydrogen, propane, methane, ethanol and methanol. Also, the superior of alternative fuels is shown by comparing the performance and emissions of alternative fueled engines to those in conventional fueled engines. Eventually, it is concluded that volumetric efficiency of the engine working on hydrogen is the lowest (28% less that gasoline fueled engine), gasoline produce more power than the all being tested alternative fuels and BSFC of methanol is 91% higher than that of gasoline while BSFC of hydrogen is 63% less than gasoline. [Copyright &y& Elsevier]

Abstract: A computer simulation of a variable stroke length, LPG fuelled, four stroke, single cylinder, water cooled spark ignition engine was done. The engine capacity was varied by varying the stroke length of the engine, which also changed its compression ratio. The simulation model developed was verified with experimental results from the literature for both constant and variable stroke engines. The performance of the engine was simulated at each stroke length/compression ratio combination. The simulation results clearly indicate the advantages and utility of variable stroke engines in fuel economy and power issues. Using the variable stroke technique has significantly improved the engine’s performance and emission characteristics within the range studied. The brake torque and power have registered an increase of about 7–54% at low speed and 7–57% at high speed relative to the original engine design and for all stroke lengths and engine speeds studied. The brake specific fuel consumption has registered variations from a reduction of about 6% to an increase of about 3% at low speed and from a reduction of about 6% to an increase of about 8% at high speed relative to the original engine design and for all stroke lengths and engine speeds studied. On the other hand, an increase of pollutants of about 0.65–2% occurred at low speed. Larger stroke lengths resulted in a reduction of the pollutants level of about 1.5% at higher speeds. At lower stroke lengths, on the other hand, an increase of about 2% occurred. Larger stroke lengths resulted in increased exhaust temperature and, hence, make the exhaust valve work under high temperature. [Copyright &y& Elsevier]

Abstract: An evaluation was performed on the efficiency and emissions from an engine fuelled with compressed natural gas (CNG) and a mixture of natural gas and hydrogen, respectively. The mixtures of CNG and hydrogen were named HCNG. Two different mixtures were investigated; pure CNG, and 29vol% H2 in CNG (named HCNG). For each mixture, four engine speeds were tested under full load conditions. For each mixture and each engine speed four different excess air ratios (λ) were chosen. The lean limit for the pure CNG tested in this engine is approximately , and the lean limit for the HCNG is even leaner, i.e. at about . This is as expected, and in accordance with the literature. Considering the total emissions of unburned hydrocarbons and nitrogen oxides, it is easily seen that the positive effect of adding hydrogen to the CNG increases as a function of lambda. By adding hydrogen to CNG, an increase in power will result in the λ investigated. The efficiency for HCNG is greater than for CNG for the same λ, and the difference in η th,brake between HCNG and CNG for the same λ increases with increasing excess air ratio. [Copyright &y& Elsevier]

[Display omitted] • The BTE and BSFC values are considerably affected by hydrogen and methanol fuel properties. • The ID and CD values are dramatically decreased by the hydrogen addition. • Methanol considerably decreases (11.82%) NO emission. • Hydrogen substantially decreases (13.06%) HC, while dramatically increases (31.68%) NO. • The optimum BSFC-NO values are obtained between 68.61 and 74.55 Nm engine loads. The main purpose of this study was to investigate the effects of hydrogen and methanol addition on the engine performance, combustion, and emission characteristics of a spark-ignition engine. The experiments were performed with pure gasoline, methanol-gasoline, and hydrogen-methanol-gasoline fuel blend under various engine loads (25Nm, 50Nm, 75Nm, and 100Nm, 100%), different lambda values (0.8, 1, and 1.2), and a constant engine speed (2000 rpm). The hydrogen energy substitute rate method was applied for hydrogen enrichment that was constituted by 5% of the total input fuel energy. The experimental results indicated that the average values of brake specific fuel consumption were increased by 11.98% with the methanol-gasoline test fuel, while decreased 4.07% with the hydrogen-methanol-gasoline fuel blend. The average values of brake thermal efficiency were slightly increased by 0.07% and 0.61% with the methanol-gasoline and hydrogen-methanol-gasoline fuel blends, respectively. The combustion characteristics were improved after adding the methanol and hydrogen. In this respect, the average ignition delay values decreased by 6.45% with the addition of the methanol in gasoline, while the combustion duration, maximum cylinder pressure, and maximum heat release rate values increased by 0.85%, 1.66%, and 2.32%, respectively. Furthermore, the ignition delay and combustion duration values were substantially affected by the addition of the hydrogen and observed to be at rates of 21.10% and 6.93% reduction, respectively. In addition, the maximum cylinder pressure and maximum heat release rate values were increased by 2.02% and 4.13%. The combustion characteristics improved after the addition of hydrogen and methanol, which also considerably affected the engine performance and emission characteristics. The average values of exhaust gas temperature, hydrocarbon, carbon dioxide were increased by 0.92%, 2.26%, and 0.156% with methanol and the values of carbon monoxide and nitrogen monoxide were decreased by 1.09% and 11.82%, respectively. However, the hydrocarbon, carbon dioxide values were decreased by 13.06%, 3.90% with the hydrogen, while the carbon monoxide, exhaust gas temperature, and nitrogen monoxide were increased by 1.84%, 1.38%, and 31.68%, respectively. Although nitrogen monoxide was considerably decreased by the methanol, a drastic increase was observed with the hydrogen. The optimum brake specific fuel consumption and nitrogen monoxide values occurred between 68.61 Nm and 74.55 Nm of the engine loads for the methanol-gasoline and hydrogen-methanol-gasoline test fuels at λ = 1 and 1.2. Overall, the engine performance, combustion, and emission characteristics were improved by the addition of hydrogen and methanol in the test fuels due to their superior fuel properties compared to gasoline. [ABSTRACT FROM AUTHOR]

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the literature mainly obtained in the CFR engine. Particular attention was paid to determine the lowest possible load limit when the engine is supplied with pure ammonia or a small amount of H2, depending on engine speed, in order to highlight the limitation during cold start conditions. It can be concluded that this engine can run stably in most of these operating conditions with less than 10% H2 (of the total fuel volume) added to NH3. Measurements of exhaust pollutants, and in particular NOx, have made it possible to evaluate the possibility of diluting the intake gases and its limitation during combustion with pure H2 under slightly supercharged conditions. In conclusion, the 10% dilution limit allows a reduction of up to 40% in NOx while guaranteeing stable operation. [ABSTRACT FROM AUTHOR]

In this study, experiments have been carried out with the use of gasoline, liquified petroleum gas (LPG), and biogas fuels in different volumetric percentages in a single cylinder, four strokes, spark ignition (SI) engine with different throttle position. In experiments, data were compared which were obtained by using gasoline, biogas and LPG; brake thermal efficiency (BTE), cylinder pressures, mean gas temperature (MGT), brake specific fuel consumption (BSFC), carbon dioxide (CO 2), carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NO x) emissions. According to the results, with the use of biogas and LPG in the full throttle opening (FTO), a 75.52% and 34.19% increase in the BSFC was determined compared to the use of gasoline, while a 16.04% and 8.95% reduction in the BTE was determined. On the other hand, with the use of biogas and LPG, a decrease of 15% and 62.03% in CO emissions, 23% and 63% decrease in HC emissions, 6.77% and 56.42% decrease in CO 2 emissions were detected compared to gasoline. In the half throttle opening (HTO), BSFC increased by 85.2% and 45.51%, while BTE decreased by 33.43% and 20.22%. In addition, a decrease of 15.97% and 47.65% on CO emissions, 21.19% and 62.38% HC emissions, 6.84% and 69.54% CO 2 emissions were detected. In terms of cylinder pressure value, with biogas and LPG, cylinder pressures decreased about 17.76% and 24.41%, respectively. On the other hand, compared to the gasoline, MGT increased with the use of LPG and decreased by the usage of biogas. [ABSTRACT FROM AUTHOR]

Energy sustainability and environmental issues pose greater challenges on different primary energy sectors as the global energy demand increases and it is projected to further increase with an upsurge in population. On the other hand, energy sources from conventional fossil-based fuels are depleting, forcing explorations in challenging and difficult locations. As a result, the use of alternative fuels received dramatic consideration to substitute these conventional fuels, of which natural gas took the significant share. However, the share of natural-gas vehicles in the current vehicle market is quite small, and it is estimated to be below 5%. This paper reviews the current resource scenarios including proven and potential reserves, current production, and consumption, along with the fueling infrastructure, distribution, and storage. It also provides summary of the development of fuel-injection technologies aimed to enhance the performance of gas engines. More attention was also given to natural-gas engines and their limitations. Parameters affecting the performance and combustion of compressed natural gas (CNG) in spark-ignition (SI) engines are thoroughly assessed, among which compression ratio and injection timing play major roles in the optimization of CNG-fueled engines. Furthermore, different technologies that help close the performance gap between conventional liquid-fuel and natural-gas engines and future directions of the research are presented. [ABSTRACT FROM AUTHOR]

The experimental investigation of2nd generation bioethanol derived from EFB of oil-palm blended with gasoline for 10, 20, 25% by volume and pure gasoline were conducted on performance and exhaust emission tests of SI engine. A four stroke, four cylinders, programmed fuel injection (PGMFI), 16 valves variable valve timing and electronic lift control (VTEC), single overhead camshaft (SOHC), and 1,497 cm3 SI engine (Honda/L15A) was used in this investigation. Engine performance test was carried out for brake torque, power, and fuel consumption. The exhaust emission was analyzed for carbon monoxide (CO) and hydrocarbon (HC). The engine was operated on speed range from 1,500 until 4,500 rev/min with 85% throttle opening position. The results showed that the highest brake torque of bioethanol blends achieved by 10% bioethanol content at 3,000 to 4,500 rpm, the brake power was greater than pure gasoline at 3,500 to 4,500 rpm for 10%bioethanol, and bioethanol-gasoline blends of 10 and 20% resulted greater bsfc than pure gasoline at low speed from 1,500 to 3,500 rpm. The trend of CO and HC emissions tended to decrease when the engine speed increased. [ABSTRACT FROM AUTHOR]