Assessment of the use of oxygenated fuels on emissions and performance of a diesel engine

Performance and emission characteristics analysis of a CI engine fueled with distilled pyrolytic waste plastic oil/ethanol/diesel blends

The current energy challenges in agriculture, industry, and transportation are aggravated by insufficient liquid petroleum fuels, strained by rapid depletion, and higher demand in the international market. Existing environmental pollution due to higher fossil fuel consumption, certainly draws the attention of many researchers to identify a better alternative fuel concerning engine efficiency and exhaust emissions. Waste plastic oil (WPO) derived by thermo-catalytic pyrolysis is found to be a promising alternative fuel due to it's similar fuel properties to diesel. WPO contains long-chain hydrocarbons and high-molecular-weight aromatics which can be eliminated by fractional distillation, resulting in the production of distilled waste plastic oil (DPO). Ethanol is added in addition to DPO in the diesel fuel mixture in order to improve combustion for better performance and reduce emissions. The current study focused on the preparation of homogenous fuel mixtures (DPO/ethanol/diesel) to evaluate it's engine efficiency and exhaust emissions as compared to pure diesel and confirmed that it has the potential to be an alternate fuel for the CI engine. Test engine trials were performed to determine the potential engine characteristics, for instance, thermal efficiency, specific fuel consumptions, and exhaust temperature, by using various fuel mixtures (80D10DPO10E, 70D15DPO15E, 60D20DPO20E, 50D25DPO25E) under different loading conditions of the test engine. Major pollutants including unburned hydrocarbon, carbon monoxide, and nitrogen oxides were measured by a standard emission analyzer. The BTE was increased by 3.7%, and the BSFC was 16.67% less for the 60D20DPO20E mixture so as to diesel at full load. CO emission was found to comparatively increase at higher concentrations and decrease at higher loads. Compared to diesel, the NOx and HC emission were shown to be lowered at low loads and increased at higher loads. The study concluded that the fuel mixture of 60D20DPO20E showed the best engine performance and reduced emissions as compared to diesel.

Investigating the Effect of a Diesel-Refined Crude Palm Oil Methyl Ester-Hydrous Ethanol Blend on the Performance and Emissions of an Unmodified Direct Injection Diesel Engine

In this research, the optimum condition for the production of refined crude palm oil methyl ester from refined crude palm oil was investigated using the response surface method via the transesterification reaction in a batch process. The refined crude palm oil was obtained by vacuum distillation of crude palm oil to extract some of the free fatty acids from the oil, providing nutritional benefits and reducing the chemical consumption of the production process. The purity of methyl ester in the refined crude palm oil methyl ester was studied to adjust four independent variables: methanol content (11-23 vol %), concentration of potassium hydroxide (4-12 g/L), stirrer speed (100-500 rpm), and reaction time (9-45 min). The results showed that methyl ester had a purity of 96.91 wt % when synthesized under optimal conditions of 18.2 vol % methanol, a potassium hydroxide concentration of 10.0 g/L, a stirring speed of 380 rpm, and a reaction time of 36.4 min at 60 °C. Refined crude palm oil methyl ester was blended with diesel and ethanol to study the feasibility of using the diesel-refined crude palm oil methyl ester-hydrous ethanol blend in an unmodified diesel engine. A comparative study of fuel properties, emissions, and performance of the diesel-refined crude palm oil methyl ester-ethanol blend was used to assess the feasibility of fuel blends (D40RM50E10, D30RM60E10, D20RM70E10, and D10RM80E10) in diesel engines at various engine speeds and loads. The results showed that the D40RM50E10 blend provided the closest performance to diesel and was environmentally friendly, as it provided nitrogen oxide and carbon monoxide emissions 32 and 55% lower than those with diesel, respectively. The test results indicated that the diesel-refined crude palm oil methyl ester-hydrous ethanol blend is an attractive alternative fuel in agricultural engines that reduces diesel consumption and benefits farmers and rural communities.

Emission and Performance Evaluation of a Diesel Engine Using Addition of Ethanol to Diesel/Biodiesel Fuel Blend

Many countries have adopted the addition of biodiesel to diesel as a way of inserting renewable content into mineral fuel and making a contribution to the environment. The addition of ethanol to the diesel/biodiesel blend to increase the renewable content of the added fuel blend and reduce the percentage of biodiesel could be a strategysince the demand for biodiesel production is high, and this fuel has a high production cost when compared to ethanol. Thus, this study evaluated the performance and the content of NOx, CO and CO2 exhaust gases from a diesel engine fueled with blends of diesel/biodiesel/ethanol: pure B7, B7E3 (B7 with 3% ethanol) and B7E10 (B7 with 10% ethanol). Emissions of fuel blends were evaluated using the engine speed variation and tested at a speed of 1500 rpm under constant load (185 Nm). Assays were performed at engine speeds of 1000, 1100, 1250, 1500 and 1750 rpm and with loads of 10, 25, 50, 75 and 100% of the maximum torque. Through the performance curves, the specific consumption and thermal efficiency were evaluated. The increase in speed and ethanol content in the diesel/biodiesel mixture increased approximately 5 to 7 and 1.4 times, respectively, in terms of the emission of exhaust gases. There was a 6% decrease in the maximum torque and power available at each speed with increasing ethanol content in the blend. However, in a vehicular application, this decrease would be perceived only at some points of the part-load regime, causing considerable reductions in thermal efficiency.

Effects of Diesel-Biodiesel-Ethanol Fuel Blend on a Passive Mode of Selective Catalytic Reduction to Reduce NO x Emission from Real Diesel Engine Exhaust Gas

The effects of ethanol on combustion and emission were investigated on a single-cylinder unmodified diesel engine. The ethanol content of 10-50 vol % was chosen to blend with diesel and biodiesel fuels. Selective catalytic reduction (SCR) of nitrogen oxides (NO _x ) in the passive mode was also studied under real engine conditions. Silver/alumina (Ag/Al₂O₃) was selected as the active catalyst, and H₂ (3000-10000 ppm) was added to assist the ethanol-SCR. The low cetane number of ethanol resulted in longer ignition delay. The diesel-biodiesel-ethanol fuel blends caused an increase in fuel consumption due to their low calorific value. The brake thermal efficiency of the engine fuelled with relatively low ethanol fraction blends was higher than that of diesel fuel. Unburned hydrocarbons (HC) and carbon monoxide (CO) increased, while NO _x decreased with ethanol quantity. The higher ethanol quantity led to increases in the HC/NO _x ratio which directly affected the performance of NO _x -SCR. Addition of H₂ considerably improved the activity of Ag/Al₂O₃ for NO _x reduction. The proper amount of H₂ added to promote the ethanol-SCR depended strongly on the temperature of the exhaust where a high fraction of H₂ was required at a low exhaust temperature. The maximum NO _x conversion of 74% was obtained at a low engine load (25% of maximum load), an ethanol content of 50 vol %, and H₂ addition of 10000 ppm.

An Overview of the Influence of Biodiesel, Alcohols, and Various Oxygenated Additives on the Particulate Matter Emissions from Diesel Engines

Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have been exploring different measures to reduce PM emissions such as using modern combustion techniques, after-treatment systems such as diesel particulate filter (DPF) and gasoline particulate filter (GPF), and alternative fuels. Alternative fuels such as biodiesel (derived from edible, nonedible, and waste resources), alcohol fuels (ethanol, n-butanol, and n-pentanol), and fuel additives have been investigated over the last decade. PM characterization and toxicity analysis is still growing as researchers are developing methodologies to reduce particle emissions using various approaches such as fuel modification and after-treatment devices. To address these aspects, this review paper studies the PM characteristics, health issues, PM physical and chemical properties, and the effect of alternative fuels such as biodiesel, alcohol fuels, and oxygenated additives on PM emissions from diesel engines. In addition, the correlation between physical and chemical properties of alternate fuels and the characteristics of PM emissions is explored.

Thermoelectric Energy Recovery in a Light-Duty Diesel Vehicle under Real-World Driving Conditions at Different Altitudes with Diesel, Biodiesel and GTL Fuels

This work focuses on the potential for waste energy recovery from exhaust gases in a diesel light-duty vehicle tested under real driving conditions, fueled with animal fat biodiesel, Gas To Liquid (GTL) and diesel fuels. The vehicle was tested following random velocity profiles under urban driving conditions, while under extra-urban conditions, the vehicle followed previously defined velocity profiles. Tests were carried out at three different locations with different altitudes. The ambient temperature (20 ± 2 °C) and relative humidity (50 ± 2%) conditions were similar for all locations. Exergy analysis was included to determine the potential of exhaust gases to produce useful work in the exhaust system at the outlet of the Diesel Particle Filter. Results include gas temperature registered at each altitude with each fuel, as well as the exergy to energy ratio (percentage of energy that could be transformed into useful work with a recovery device), which was in the range of 20–35%, reaching its maximum value under extra-urban driving conditions at the highest altitude. To take a further step, the effects of fuels and altitude on energy recovery with a prototype of a thermoelectric generator (TEG) were evaluated.