Search

Out of various strategies to extenuate the diesel engine emissions, use of water-blended diesel fuel in emulsified form is found to be a prominent option. The studies carried out by various researchers give quite inconsistent results for optimum water concentration, surfactant concentration, and HLB value. An effort has been made in this paper to analyze this inconsistency of water concentration and surfactant for engine emissions and performance along with the effect of compression ratio. The work has been carried out on a non-road, constant rpm, VCR (variable compression ratio) diesel engine. Different emulsions of 5%, 10%, 15%, and 20% water-in-diesel with 3% emulsifier concentration were tested on the diesel-optimized engine at CR 21. The results showed that emulsion of 15% water-in-diesel is optimal on the basis of emissions and performance. Further, the selected 15% emulsion is tested with 4% emulsifier concentration. It improved the stability of emulsion and performance of the engine with slight adverse effects on the NOx emissions. Then, emulsion with 4% surfactant and 15% water is tested to determine optimum compression ratio for emulsified fuels. CR 20 is found in optimum. Remarkably 9.28% improvement in BTE is observed reaching up to 23.89% as compared to 21.86% with bare diesel. 25.1% reduction in NOx and more than 50% reduction in smoke is observed. Overall, it is concluded that the water-blended diesel emulsion could serve as a fuel-efficient cleaner combustion technology and needs to be standardized. Abbreviations HLB: Hydrophile–Lipophile Balance; Cv: Calorific Value; W/D: Water in Diesel; PM: Particulate matter; RPM: Rotation per minute; HC: Hydrocarbon; CR: Compression Ratio; EGT: Exhaust Gas Temperature; BTE: Brake Thermal Efficiency; NOx: Oxides of Nitrogen; BSFC: Brake specific fuel consumption [ABSTRACT FROM AUTHOR]

The chief objective of this study is to utilize non‐edible, carbon‐rich oil derived from Prunus domestica seeds as blended fuel. The combustion efficiency of derived blends shall further be enhanced by blending higher alcohol into biodiesel/diesel blends. This work details the impact of effectively utilizing waste and non‐edible oil to replace fossil fuels partially. In this study, the P. domestica is trans‐esterified to methyl ester and blended with diesel at 20%. Further to enhance the ignition nature, butanol, higher alcohol, is blended to P. domestica biodiesel/diesel blends at 5% and 10%. The ignition pattern of the modified fuels is extensively studied and compared with diesel in a stationary research diesel engine. This study involves four fuel samples, namely, neat P. domestica methyl ester and is termed PDME. 20% of PDME is blended with 80% diesel is referred to as PDME20. 20% of PDME with 5% n‐butanol and 75% diesel is termed PDME20Bu5D75, 20% of PDME with 10% n‐butanol and 70% diesel is termed as PDME20Bu10D70 and diesel. Addition of PDME and butanol at different blends found miscible with diesel. PDME and butanol provided a suitable time for reaction and mixing, complete combustion, higher O2 content, and rich fuel‐air mixture, resulting in lower emissions than diesel. Further, butanol aided better atomization, effective combustion and resulted in higher efficiency with lower fuel consumption. Adding butanol also lowered the viscosity and improved the mixing process, and produced better in‐cylinder pressure and heat release rate. [ABSTRACT FROM AUTHOR]

The rapid depletion of conventional fuel reserves and the increase in environmental pollution prompted the search for a sustainable energy solution. Biodiesel is one of the most promising energy substitutes with similar properties as conventional diesel fuel. Surplus availability of palm oil makes it suitable for biodiesel production. Due to the lack of availability of review articles that cover the entire process of palm biodiesel production and its optimum use in diesel engines, the authors were motivated to write this article. Cultivation parameters of palm trees, extraction of oil, and physicochemical properties of palm oil–based biodiesel are explained in this review. The production of palm biodiesel from raw oil can be done through pyrolysis, micro-emulsification, blending, hydro-esterification, and transesterification processes. For high biodiesel yield and less cost of operation, the transesterification method is adopted. The performance and emission parameters of diesel engines that operated on palm biodiesel and its blends are also explained. There is a decrease in brake thermal efficiency and an increase in brake-specific fuel consumption observed with the use of palm biodiesel in diesel engines. A reduction in CO and HC emissions and an increase in NOx emissions are found due to the oxygenating nature of palm biodiesel. This article provides the scientific approach to find out the optimum parameters for palm biodiesel production and its efficient use in compression ignition engines. [ABSTRACT FROM AUTHOR]

Continuously growing world's energy demand and global climate change due to green house gas emissions have created need to find out renewable and sustainable energy solution. Biodiesel is one of the most promising substitute of diesel fuel that can be produced from vegetable oils, animal fats, waste oils etc. It is broadly classified in four generations i.e. edible oils (first generation), non-edible oils (second generation), waste oils (third generation) and advance solar biodiesel (fourth generation). There are some limitations associated with biodiesel as a fuel in diesel engines like cold flow, oxidation stability etc. Selection of biodiesel due to the above reasons is region specific and depends on the specific properties which are mainly governed by fatty acid composition of that oil. This review discusses the physicochemical properties of different generation biodiesel using 52 types of feedstocks. The chemical composition and physicochemical properties of 31 raw oils have also been discussed. As different fatty acid methyl esters (FAME) structures behave differently, it is not possible to develop a unique approach for obtaining optimum composition of FAME. The low concentration of polyunsaturated FAME and long-chain saturated FAME is more favorable for oxidation stability, low-temperature operability, and satisfactory performance. American Society for Testing and Materials (ASTM), European committee for standardization (CEN), Bureau of Indian Standards (BIS), etc. provided the specifications for the biodiesel and their blends. [ABSTRACT FROM AUTHOR]

Increasing environmental concern, human health and the continuous upgradation in the stringent standards of vehicular emissions have shown much interest in cleaner diesel fuels. Out of various strategies to mitigate the diesel engine emissions, use of water blended diesel in the form of emulsion has grabbed sufficient attention of the fuel research community. Various researches have shown that water-emulsified diesel has sufficient potential to improve the engine performance simultaneously with a significant reduction in the levels of nitrogen oxides (NOx) and particulate matter (PM) emissions. Micro-explosion phenomenon of combustion in emulsion fuel helps to provide efficient and complete combustion which in turn improves brake thermal efficiency. The current study presents a comprehensive review of the usage of water-emulsified diesel fuel in CI engines. Focusing on the performance, combustion, and emission analysis, it also talks in detail about the principle and the chemistry involved in making of a stable and homogeneous water-diesel emulsion compatible for CI engine. The literature survey concludes two crucial points. First, the water-blended diesel emulsion serves as an economical, fuel efficient, and cleaner combustion technology. Second, the optimum blend ratio, emulsifier quantity, and proper process differs in almost all the research papers and hence needed to be standardized. [ABSTRACT FROM AUTHOR]

The conventional petroleum fuels are depleting rapidly and the prices are going up day by day. Moreover, these petroleum fuels are responsible for green house emissions and other forms of pollution in the environment. Among various options available, the fuels derived from vegetable oils have emerged as promising alternate fuels for IC engines. The use of unmodified or straight vegetable oils in diesel engine creates operational problems due to their high viscosity and poor volatility. In the present work, an experimental setup has been designed to reduce the viscosity of the fuel by blending Karanj oil with Petro-Diesel and preheating the Karanj-Diesel blend. Experiments are also conducted to determine the optimal injection pump timing for the selected blend, with respect to the engine performance parameters. Experiments are performed using Petro-Diesel and preheated Karanj-Diesel blend (in ratio 40:60 by volume) on constant speed direct injection C.I. engine. The effect of injection timing on the preheated Karanj-Diesel blend is investigated and the results are analyzed. On the basis of results obtained, the optimal injection timing is determined for Karanj-Diesel blend, which is found to be 19° BTDC. [ABSTRACT FROM AUTHOR]

• A novel approach of cow-urine (gomutra) emulsification in diesel is explored. • 15% Cow-urine emulsification in diesel was found optimum. • Significant 13.2% improvement in brake thermal efficiency was observed. • Water and urea content of the GMD emulsion resulted in reduced exhaust emissions. • NO x and smoke emissions got reduced up to 31.8% and 36.9% respectively. Apart from the various emission reduction strategies, a novel concept of cow-urine emulsification in diesel has been explored in this study. In India, cow urine is easily and readily available as gomutra distillate. It constitutes of around 95% water and exhibits the benefits of water emulsification to improve the brake thermal efficiency. Additionally, it consists of urea which works as a reducing agent and significantly cuts-down the NO x emissions. Sodium, magnesium, calcium and potassium present in the cow-urine are also expected to enhance the fuel properties as found in various other researches. Emulsions containing 5%, 10%, 15% and 20% (v/v) cow-urine were tested on a stationary C.I. engine. The 15% emulsion was found to be optimum with a remarkable increase in BTE reaching up to 24.8% as compared to 21.9% with base diesel. In emissions, NO x and smoke got reduced by maximum up to 31.8% and 36.9% respectively. At lower loads, the CO emissions were found to be increased but at higher loads, it was also decreased. No significant variation in HC emissions was observed. Overall, cow-urine emulsified diesel fuel was found to be an energy-efficient and cleaner alternative fuel for stationary C.I. engine application. [ABSTRACT FROM AUTHOR]

Abstract: Presently majority of the world’s energy demand is met by fossil fuels. These fuels are depleting at an alarming rate. Thus in future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Among the various alternative fuels, hydrogen is a long-term renewable and least polluting fuel (produced from renewable energy sources). Its clean burning characteristics help to meet the stringent emission norms. Majority of the work using hydrogen as a fuel is being done in spark ignition engine, however, in this experimental investigation efforts have been made to utilize it in compression ignition engine. In this investigation, the performance and emission characteristics were studied on a direct injection, single cylinder, four-stroke, air-cooled, stationary diesel engine coupled to an electric dynamometer. Hydrogen-enriched air with carburetion technique was used as intake charge in the above mentioned engine with 10% & 20% exhaust gas recirculation (EGR). Performance parameters such as specific energy consumption, brake specific fuel consumption, brake thermal efficiency were determined and emissions such as oxides of nitrogen, unburned hydrocarbon, carbon monoxide, carbon dioxide, oxygen and exhaust gas temperature were measured. Dual fuel operation with hydrogen induction coupled with exhaust gas recirculation results in lowered emission level and improved performance level compared to the case of neat diesel operation. [Copyright &y& Elsevier]