Ali Keskin

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.

Influence of tall oil biodiesel with Mg and Mo based fuel additives on diesel engine performance and emission.

The purpose of this study is to investigate influences of tall oil biodiesel with Mg and Mo based fuel additives on diesel engine performance and emission. Tall oil resinic acids were reacted with MgO and MoO(2) stoichiometrically for the production of metal-based fuel additives (combustion catalysts). The metal-based additives were added into tall oil biodiesel (B60) at the rate of 4 micromol/l, 8 micromol/l and 12 micromol/l for preparing test fuels. In general, both of the metal-based additives improved flash point, pour point and viscosity of the biodiesel fuel, depending on the rate of additives. A single cylinder DI diesel engine was used in the tests. Engine performance values did not change significantly with biodiesel fuels, but exhaust emission profile was improved. CO emissions and smoke opacity decreased by 56.42% and by 30.43%, respectively. In general, low NO(x) and CO(2) emissions were measured with the biodiesel fuels.

Biodiesel Production from Terebinth (Pistacia Terebinthus) Oil and its Usage in Diesel Engine

This paper presents the results of investigations carried out on a three-cylinder, fourstroke, and direct-injection CI engine operated with terebinth (pistacia terebinthus) oil biodiesel. Terebinth oil was squized using the extraction method and therefore terebinth oil biodiesel was produced via the transesterification method. Terebinth oil biodiesel (B)—diesel fuel (D) blends were tested in a direct injection diesel engine at full load condition. Power values showed a trend of decreasing with all biodiesel fuels at high engine speeds. Specific fuel consumption (SFC) values increased depending on the amount of biodiesel in the test fuels. In general, exhaust emission profile of biodiesel fuels improved. CO and CO2 emissions decreased up to 34.54% and 10.69% respectively. However, NOx emissions increased up to 32.97%.

The Effects of Ethanol and Propanol Additions Into Unleaded Gasoline on Exhaust and Noise Emissions of a Spark Ignition Engine

Abstract Exhaust and noise emissions of a four-stroke spark ignition engine were investigated by using ethanol–gasoline blends and propanol–gasoline blends. Ethanol and propanol were added to unleaded gasoline at volume percent levels of 4, 8, 12, 16, and 20%. Higher octane number, lower sulphur content, and higher oxygen content were important advantageous of the blend fuels. In general, exhaust emission profile of the engine improved when ethanol and propanol were added into the unleaded gasoline. The CO and HC emissions with ethanol–gasoline blends and propanol–gasoline blends decreased by 65.56 and 33.92%, respectively. NO and CO2 emissions with the blend fuels showed a trend of increasing. In addition, noise emissions with gasoline–ethanol blends decreased slightly at low loads. However, at the other tests, noise levels showed a trend of increasing with the blend fuels.

The Investigation of Performance and Emissions Characteristics of Tall Oil Biodiesel With a Co-based Additive

Abstract In this study, the effects of tall oil biodiesel with cobalt (Co)-based additive on engine performance and exhaust emissions have been experimentally investigated. Co-based additive at the rate of 4, 8, and 12 μmol/l was added to mixtures of 60% tall oil methyl ester and 40% diesel fuel (T60). The engine tests were performed at full load condition in a single-cylinder diesel engine. Biodiesel fuels had no noteworthy influence on engine torque and the power output values. Catalyst effects of Co-based additive improved specific fuel consumption values, CO emissions, and smoke emissions. On the other hand, higher NOx emissions were measured at low engine speed.

The Influence of Ethanol–Gasoline Blends on Spark Ignition Engine Vibration Characteristics and Noise Emissions

Abstract Engine vibration characteristics and noise emission of a two stroke spark ignition engine were investigated by using blends of ethanol–gasoline–oil (25% E–70% G–5% O and 50% E–45% G–5% O) and pure gasoline. Engine test conditions were 0.86 kW (5.5 Nm) at 1,500 rpm, 1.25 kW (6.0 Nm) at 2,000 rpm, and 1.83 kW (7.0 Nm) at 2,500 rpm. A high sensitivity electronic vibration analysis system was used for measurement of frequency spectrum of the spark ignition engine vibration. Higher octane number, lower sulphur content, and higher oxygen content were important advantages of blend fuels. Experiment results indicated that when the blend fuels were used, vibration characteristics of the engine changed significantly at 1,500 and 2,500 rpm. In general, in comparison with gasoline, vibration amplitudes and noise emission of the engine with the blend fuels showed a trend of increasing. These results are probably due to oxygen content and higher latent heat of evaporation of ethanol, in which the increasing rate of pressure (dp/dt) and peak pressure values in the cylinder rise during the combustion processes. There was a relation between vibration and noise emissions, due to the increasing trend of them at the same test condition.

Biodiesel Production from Free Fatty Acids Obtained with Neutralization of the Crude Glycerin

Abstract In this study, palm oil fatty acids which were obtained from crude glycerin by neutralization were used for biodiesel production. The crude glycerin is a by-product of a biodiesel production process. Mixtures of the biodiesel with diesel fuel were tested in an unmodified direct injection diesel engine at full load condition. In general, specific fuel consumption of biodiesel fuels increased depending on the amount of biodiesel in the test fuels. CO emission and smoke opacity decreased up to 40.87 and 23.69%, respectively. NOx emissions increased up to 12.36%. CO2 emission showed a trend of decreasing with biodiesel fuel.

The Optimization of the Esterification Reaction in Biodiesel Production from Trap Grease

Abstract In this experimental study, biodiesel production from waste oils (trap grease), which were obtained from an oil separator, was carried out by using sulfuric acid as the catalyst and esterification process. The main variables involved in the esterification process, including methanol/waste cooking oils ratio, amount of acid catalyst, reaction time, and reaction temperature, were analyzed. Because the waste cooking oils contain high free fatty acid above 65%, the esterification process has been preferred. Methanol was used as alcohol in this process because of its low cost, and sulfuric acid was preferred as the catalyst because it gives very high yields in alkyl esters. Experiments have been performed to determine optimum conditions for this esterification process in different molar ratios, catalyst amounts, reaction times, and reaction temperatures. The optimum experimental conditions, which were obtained from the esterification process, were methanol/waste cooking oils ratio 9/1, with 9 wt% sulfuric acid catalyst, reaction time 120 min, and reaction temperature 60°C. The yield of biodiesel was 93.98% at optimum esterification process. Biodiesel and its blends with diesel were characterized for their physical properties referring to a substitute for diesel fuel. The results show that blends with a percentage of the biodiesel below 40 vol% had their physical properties within EN590 standard, which indicated that these could be used in engines without a major modification.

Evaluation of Biodiesel Production, Engine Performance, and Emissions

Nowadays, to decrease environmental pollution and dependence on fossil-based fuels, research on alternative renewable energy sources has been increasing. One such renewable energy source is biodiesel, which is used as an alternative fuel for diesel engines. Biodiesel is renewable, nontoxic, biodegradable, and environmentally friendly. Biodiesel is domestically produced from vegetable␣oil (edible or nonedible), animal fat, and used cooking oils. In the biodiesel production process, oil or fat undergoes transesterification reaction through use of simple alcohols such as methanol, ethanol, propanol, butanol, etc. Use of methanol is most feasible because of its low cost, and physical and chemical advantages. Acid catalysis, alkali catalysis, and enzyme catalysis are usually used to improve the reaction rate and yield. Glycerol is a byproduct of the reaction and can be used as an industrial raw material. In this study, biodiesel production methods (direct use, pyrolysis, microemulsion, transesterification, supercritical processes, ultrasound- assisted, and microwave-assisted) and types of catalyst (homogeneous, heterogeneous, and enzyme) have been evaluated and compared. In addition, the effects of biodiesel and its blends on diesel engine performance and exhaust emissions are described and reviewed.

The Influence of Diesel Fuel-biodiesel-ethanol-butanol Blends on the Performance and Emission Characteristics of a Diesel Engine

In this study, performance and exhaust emissions of a diesel engine fueled with Fuel A (60% diesel–30% biodiesel–5% ethanol–5% butanol) and Fuel B (40% diesel–50% biodiesel–5% ethanol–5% butanol) were investigated. The biodiesel produced from trap grease was obtained with an oil separator. Fuel A and Fuel B were tested in a single cylinder, four-stroke diesel engine at full load conditions. Compared with diesel fuel, the performance characteristics of blend fuels slightly deteriorated while the emission characteristics improved significantly. CO and HC emissions decreased by 87.01 and 87.50%, respectively.