Showing papers on "Diesel engine published in 2015"

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Abstract: Diesel engines have high efficiency, durability, and reliability together with their low-operating cost. These important features make them the most preferred engines especially for heavy-duty vehicles. The interest in diesel engines has risen substantially day by day. In addition to the widespread use of these engines with many advantages, they play an important role in environmental pollution problems worldwide. Diesel engines are considered as one of the largest contributors to environmental pollution caused by exhaust emissions, and they are responsible for several health problems as well. Many policies have been imposed worldwide in recent years to reduce negative effects of diesel engine emissions on human health and environment. Many researches have been carried out on both diesel exhaust pollutant emissions and aftertreatment emission control technologies. In this paper, the emissions from diesel engines and their control systems are reviewed. The four main pollutant emissions from diesel engines (carbon monoxide-CO, hydrocarbons-HC, particulate matter-PM and nitrogen oxides-NOx) and control systems for these emissions (diesel oxidation catalyst, diesel particulate filter and selective catalytic reduction) are discussed. Each type of emissions and control systems is comprehensively examined. At the same time, the legal restrictions on exhaust-gas emissions around the world and the effects of exhaust-gas emissions on human health and environment are explained in this study.

Effect of dispersion of various nanoadditives on the performance and emission characteristics of a CI engine fuelled with diesel, biodiesel and blends—A review

Abstract: The preference given to biodiesel in a diesel engine has gained importance over the past two decades, due to its various environmental and economic benefits. There exists a lot of scope for further improvement in the performance and emission reduction with biodiesel as the fuel. Fuel adulteration is one of the important techniques for performance enhancement and emission reduction, compared to other techniques such as engine modification and exhaust gas treatment. In recent years, the use of nanoparticles as additives in diesel improves the thermo physical properties, such as high surface area-to-volume ratio, thermal conductivity, and mass diffusivity, when dispersed in any base fluid medium. Based on the results available in the literature, it has been found that nanoadditives with diesel, biodiesel and blends improve the flash point, fire point, kinematic viscosity and other properties, depending upon the dosage of the nanofluid additives. In the present work a review has been made to study the effect of dispersion of various nanoadditives on the enhancement of the performance and emission reduction characteristics of a CI engine fuelled with diesel, biodiesel, and its blends and a summary of the observation made from the literatures are reported in the conclusion.

Performance and emission assessment of diesel-biodiesel-ethanol/bioethanol blend as a fuel in diesel engines: a review.

Abstract: The aim of this review is to study the opportunities and prospects of introducing diesel–biodiesel–ethanol/bioethanol blend as fuel in the existing diesel engines. The study is based on the engine emissions and its performance. The energy policies and the ever growing energy demand of the world, require an alternative to fossil fuels. In this quest, the diesel–ethanol blend or the diesohol blend might be a good option. But this blend possesses stability problem as well as inferior physicochemical properties when compared to diesel fuel and needs additives to remain stable. When biodiesel is used as an additive in this diesohol blend, it improves the physicochemical properties of the ternary blend, engine performance and also increases the renewable portion of the blend. First the engine performance and emissions data found by using diesel–biodiesel–ethanol/bioethanol ternary blends are accumulated. Then the results of the scientists and investigators are discussed to evaluate its potential as an alternative to fossil diesel fuel. The physicochemical properties of ternary blends are found to be almost similar to the diesel fuel. These ternary blends significantly reduce the PM (particulate matter) emissions from the diesel engine but the emissions of NO x (nitrogen oxides), soot and smoke, HC (hydrocarbon), CO (carbon monoxide), CO 2 (carbon dioxide) and the carbonyl compounds depend on the operating conditions of the engine and remain almost similar to the diesel fuel exhaust.

Intermediate Volatility Organic Compound Emissions from On-Road Diesel Vehicles: Chemical Composition, Emission Factors, and Estimated Secondary Organic Aerosol Production

Abstract: Emissions of intermediate-volatility organic compounds (IVOCs) from five on-road diesel vehicles and one off-road diesel engine were characterized during dynamometer testing The testing evaluated the effects of driving cycles, fuel composition and exhaust aftertreatment devices On average, more than 90% of the IVOC emissions were not identified on a molecular basis, instead appearing as an unresolved complex mixture (UCM) during gas-chromatography mass-spectrometry analysis Fuel-based emissions factors (EFs) of total IVOCs (speciated + unspeciated) depend strongly on aftertreatment technology and driving cycle Total-IVOC emissions from vehicles equipped with catalyzed diesel particulate filters (DPF) are substantially lower (factor of 7 to 28, depending on driving cycle) than from vehicles without any exhaust aftertreatment Total-IVOC emissions from creep and idle operations are substantially higher than emissions from high-speed operations Although the magnitude of the total-IVOC emissions can vary widely, there is little variation in the IVOC composition across the set of tests The new emissions data are combined with published yield data to investigate secondary organic aerosol (SOA) formation SOA production from unspeciated IVOCs is estimated using surrogate compounds, which are assigned based on gas-chromatograph retention time and mass spectral signature of the IVOC UCM IVOCs contribute the vast majority of the SOA formed from exhaust from on-road diesel vehicles The estimated SOA production is greater than predictions by previous studies and substantially higher than primary organic aerosol Catalyzed DPFs substantially reduce SOA formation potential of diesel exhaust, except at low speed operations

LPG diesel dual fuel engine – A critical review

Abstract: The engine, which uses both conventional diesel fuel and LPG fuel, is referred to as ‘LPG–diesel dual fuel engines’. LPG dual fuel engines are modified diesel engines which use primary fuel as LPG and secondary fuel as diesel. LPG dual fuel engines have a good thermal efficiency at high output but the performance is less during part load conditions due to the poor utilization of charges. This problem can be overcome by varying factors such as pilot fuel quantity, injection timing, composition of the gaseous fuel and intake charge conditions, for improving the performance, combustion and emissions of dual fuel engines. This article reviews about the research work done by the researchers in order to improve the performance, combustion and emission parameters of a LPG–diesel dual fuel engines. From the studies it is shown that the use of LPG in diesel engine is one of the capable methods to reduce the PM and NOx emissions but at same time at part load condition there is a drop in efficiency and power output with respect to diesel operation.

Effects of higher ratios of n-butanol addition to diesel–vegetable oil blends on performance and exhaust emissions of a diesel engine

Abstract: n-Butanol is a promising next generation alternative fuel for stabilizing diesel fuel–vegetable oil blends at low temperatures. In this study, the effects of higher n-butanol contents in diesel fuel–vegetable oil blends in a diesel engine were investigated. Ternary blends of diesel fuel (D)–cotton oil (CtO)–n-butanol (nB) as percentages (vol.%) of 60%D–10%CtO–30%nB (TB1), 50%D–30%CtO–20%nB (TB2), 30%D–30%CtO–40%nB (TB3), 30%D–10%CtO–60%nB (TB4) and 20%D–20%CtO–60%nB (TB5) were selected in the soluble area of the ternary phase diagram for low temperature (−15 °C) operability. The tests were conducted employing each of the above ternary blends and diesel fuel, with the engine operating at full load and eight different engine speeds between 1800 and 4400 rpm. Increasing presence of n-butanol in the blends improved density, kinematic viscosity and cold filter plugging point (CFPP), while deteriorated cetane number (CN) and heating value of the ternary blends. Experimental test results of ternary blends showed that average brake torque, brake power, brake thermal efficiency (BTE) and exhaust gas temperature decreased, while brake specific fuel consumption (BSFC) increased with increasing presence of n-butanol in the blends. Addition of n-butanol to diesel fuel–vegetable oil blends increased oxides of nitrogen (NO and NO 2 ) formations, while drastically decreasing formation of carbon monoxide (CO) and hydrocarbon (HC) emissions. TB4 and TB5, which have the highest ratio of n-butanol, are promising candidate for decreasing CO and HC emissions at the expense of increasing BSFC.