Comparison of aldehyde emissions simulation with FTIR measurements in the exhaust of a spark ignition engine fueled by ethanol

This work presents a numerical simulation model for aldehyde formation and exhaust emissions from ethanol-fueled spark ignition engines. The aldehyde simulation model was developed using FORTRAN software, with the input data obtained from the dedicated engine cycle simulation software AVL BOOST. The model calculates formaldehyde and acetaldehyde concentrations from post-flame partial oxidation of methane, ethane and unburned ethanol. The calculated values were compared with experimental data obtained from a mid-size sedan powered by a 1.4-l spark ignition engine, tested on a chassis dynamometer. Exhaust aldehyde concentrations were determined using a Fourier Transform Infrared (FTIR) Spectroscopy analyzer. In general, the results demonstrate that the concentrations of aldehydes and the source elements increased with engine speed and exhaust gas temperature. The measured acetaldehyde concentrations showed values from 3 to 6 times higher than formaldehyde in the range studied. The model could predict reasonably well the qualitative experimental trends, with the quantitative results showing a maximum discrepancy of 39% for acetaldehyde concentration and 21 ppm for exhaust formaldehyde

Analysis of processing methods for combustion pressure measurement in a diesel engine

This paper analyzes combustion chamber pressure data processing methods related to the number of cycles averaged, top dead center referencing and pressure referencing (pegging). A total of 1000 consecutive engine cycles were measured in a four-cylinder diesel engine. The number of cycles that minimizes the influence of cycle-to-cycle oscillations depends on engine operating conditions and the parameters under analysis. The top dead center (TDC) referencing, using the motored curve, revealed that the thermodynamic loss shifts the peak pressure − 0.4 °CA from TDC. Four pegging methods were compared—least-squares, fixed-point, three-point and two-point—introducing as main novelty the fact they have not been previously investigated on the same baseline conditions. The least-squares based method showed the lowest sensitivity to random noise, but with longer processing time, and the fixed-point method presented higher dispersion in the heat release analysis. The three-point referencing method considers a variable polytropic coefficient, but suffers from noise sensitivity, and the two-point referencing method presented close values and higher dispersion in comparison with the least-squares method. The choice of which method to use depends on the type of analysis, signal quality and processing time available

Regional Electric Vehicle Energy Consumption and Carbon Emissions in Great Britain

This work presents the regional differences in electric vehicle (EV) real-world energy consumption and associated carbon emissions during charging in Great Britain (GB). A model was developed considering the variability in road traffic, ambient temperature, and electricity grid profile between the GB regions on EV carbon emissions under uncontrolled and smart scenarios. The results show the variations in EV energy consumption and carbon emissions impacted by where, when, and how an EV is driven and charged. Carbon emission reduction varies from 5% to 33% between the regions when switching to delayed smart charging, shifting the charging process outside peak hours. An optimised smart charging that moves the charging events to periods of low grid carbon intensity reduces carbon emissions from 6% to 55%, affected by region grid carbon intensity and energy consumption

Analysis of CO 2 emissions and techno-economic feasibility of an electric commercial vehicle

In order to attain emissions reduction targets to improve air quality and reduce global warming, electric vehicles (EVs) arise as alternatives to conventional vehicles fueled by fossil fuels. In this context, this work presents a comparative study between an EV and its conventional version, a medium-duty, diesel engine powered vehicle, from road tests following a standard cycle in urban driving conditions. The performance parameters evaluated are EV electric energy consumption and carbon dioxide (CO2) emissions from electricity generation and, for the conventional vehicle, exhaust CO2 emissions and energy consumption calculated from fuel consumption and heating value. Five scenarios were built to conduct an economic viability study in terms of payback and net present value (NPV). Considering the conditions applied, the results from the environmental analysis showed that CO2 emissions from the EV was 4.6 times lower in comparison with the diesel vehicle. On the other hand, the economic analysis revealed that the viability of the EV is compromised, mainly due to the imported parts with unfavorably high exchange rates. In the best scenario and not considering revenue from commercial application, the calculated payback period of the EV is 13 years of operation

Combustion characteristics, performance and emissions from a diesel power generator fuelled by B7-ethanol blends

The effects of fuel blends containing 5, 10 and 15 wt.% of anhydrous ethanol in diesel oil with 7% of biodiesel (B7) on performance, emissions and combustion characteristics of a diesel power generator are investigated. The engine was tested with its original configuration, with the fuel blends directly injected into the combustion chamber, and the applied load varied from 5 to 37.5 kW. The results were compared with standard B7 operation, and showed that in in-cylinder peak pressure and heat release rate were decreased at low loads and increased at high loads with the use of ethanol. Increasing ethanol concentration caused increased ignition delay, decreased combustion duration and reduced exhaust gas temperature. The use of ethanol decreased carbon dioxide (CO2) emissions, up to 8.6% lower than B7. Carbon monoxide (CO), total hydrocarbons (THC) and oxides of nitrogen (NOX) emissions showed different behavior, depending on load and ethanol concentration

Model for Energy Consumption and Costs of Bioethanol production from Wastepaper

This work investigates bioethanol production from wastepaper via acid and enzymatic hydrolysis with the aim to attain the highest possible yield, including an evaluation of energy consumption of the production processes and costs involved. A mathematical model was designed using MATLAB software, in which pre-calculated chronological stages have been specified with the parameters that significantly affect the bioethanol yield, including type and number of consumables, reaction temperature and residence time. The independent variables have been decided based on recommended values found in the literature and are provided as suggestions to the user, who is also given the choice to manually input the values. Mass and energy balance are carried out for each process stage of bioethanol production in order to calculate the energy consumption of the chemical reactions. The model also calculates the bioethanol yield per 100 g of lignocellulosic biomass and the related costs. A comparison between enzymatic and acid hydrolysis bioethanol is presented by a line chart on the software interface, helping the understanding of the effects of the independent variable parameters. As a result, the most optimal conditions to produce the highest yield of bioethanol and therefore increasing the efficiency of a process is obtained. The model is expected to aid in the reduction of laboratory-based experiments being conducted, saving time, human errors, costly microorganisms and other consumables

Exergoeconomic analysis of an absorption refrigeration and natural gas-fueled diesel power generator cogeneration system

This work presents a thermoeconomic analysis of a cogeneration system using the exhaust gas from a natural gas-fueled diesel power generator as heat source for an ammonia-water absorption refrigeration system. The purpose of the analysis is to obtain both unit exergetic and exergoeconomic costs of the cogeneration system at different load conditions and replacement rates of diesel oil by natural gas. A thermodynamic model of the absorption chiller was developed using the Engineering Equation Solver (EES) software to simulate the exergetic and exergoeconomic cogeneration costs. The data entry for the simulation model included available experimental data from a dual-fuel diesel power generator operating with replacement rates of diesel oil by natural gas of 25%, 50% and 75%, and varying engine load from 10 kW to 30 kW. Other required data was calculations using the GateCycle software, from the available experimental data. The results show that, in general, the cogeneration cold unit exergetic and exergoeconomic costs increases with increasing engine load and decreases with increasing replacement rate of diesel oil by natural gas under the conditions investigated. Operating with 3/4 of the rated engine power and replacing 50% of diesel oil by natural gas, the exergoeconomic cost of the produced power is increased by 75%, and the exergoeconomic cost of the produced cold is decreased by 17%. The electric power unit exergetic and exergoeconomic costs indicate that the replacement of diesel oil by natural gas is feasible in the present considerations for engine operation at medium and high loads

Simulation of a diesel engine operating with ethanol to reduce pollutant emissions

In this study a computational model to simulate the operation of a diesel engine fuelled by blends of 95% diesel oil + 5 % biodiesel (B5) and anhydrous ethanol was developed. The model was developed using the Engineering Equation Solver (EES) software and calculates fuel and air properties and the thermodynamic processes of the engine cycle. Ethanol injection was investigated by two different techniques: direct injection in the combustion chamber, together with B5, and indirect injection in the intake air system, with B5 being directly injected in the combustion chamber. Fuel/air mixture equivalence ratio, compression ratio, and the injected amount of ethanol were varied to obtain the cycle temperature and pressure diagrams, fuel consumption, indicated power, and exhaust gas composition. Fuel/air mixture equivalence ratio was varied from 0.7 to 0.9, compression ratio was varied from 15:1 to 19:1, directly injected ethanol concentration was varied up to 20 % of the total fuel amount injected, and intake system injected ethanol concentration was varied up to 50 % of the total fuel amount injected. The results demonstrate that the use of ethanol can reduce carbon monoxide (CO) and oxides of nitrogen (NOX) emissions, slightly penalizing the net cycle work and increasing fuel consumption. Direct ethanol injection in the combustion chamber was shown to be more advantageous technique than indirect ethanol injection in the intake system

Hydrogen addition to ethanol-fuelled engine in lean operation to improve fuel conversion efficiency and emissions

This work applies computer simulation to investigate the combined approach of hydrogen (H2) addition with lean operation to enhance the potential of ethanol as a clean engine fuel for low-carbon transportation. To this end, this research evaluates how this operation regime impacts brake power, fuel conversion efficiency, and exhaust emissions. A dedicated software was used to perform a parametric study with varying amount of hydrogen addition and excess air ratio. The software combustion and performance parameters were calibrated against available experimental data and optimised for engine operation at the tested conditions. The results show that hydrogen addition does not produce noticeable effects on brake power and fuel conversion efficiency for lean operation with up to 20% air excess. However, for operation with 40% air excess, 6% H2 addition is necessary to keep the power at the same level of the engine baseline condition while simultaneously improving fuel conversion efficiency. Operation in the range of air excess between 10% and 30% together with hydrogen addition up to 2% can simultaneously produce noticeable improvements of fuel conversion efficiency, carbon monoxide (CO) and hydrocarbon (HC) emissions, without compromising brake power and oxides of nitrogen (NOX) emissions

Physical-chemical properties of waste cooking oil biodiesel and castor oil biodiesel blends

This work presents the physical-chemical properties of fuel blends of waste cooking oil biodiesel or castor oil biodiesel with diesel oil. The properties evaluated were fuel density, kinematic viscosity, cetane index, distillation temperatures, and sulfur content, measured according to standard test methods. The results were analyzed based on present specifications for biodiesel fuel in Brazil, Europe, and USA. Fuel density and viscosity were increased with increasing biodiesel concentration, while fuel sulfur content was reduced. Cetane index is decreased with high biodiesel content in diesel oil. The biodiesel blends distillation temperatures T10 and T50 are higher than those of diesel oil, while the distillation temperature T 90 is lower. A brief discussion on the possible effects of fuel property variation with biodiesel concentration on engine performance and exhaust emissions is presented. The maximum biodiesel concentration in diesel oil that meets the required characteristics for internal combustion engine application is evaluated, based on the results obtained