Lower Exhaust Gas Temperature Research Articles

Study of Spark-Ignition Engine Fueled with Hydrogen Produced by the Reaction Between Aluminum and Water in Presence of KOH

Hydrogen is seen as one of the important energy vectors of the century. There are several alternatives procedures to produce it in high purity; aluminum corrosion could be considered as one of the most attractive ones. The use of hydrogen derived with this process in spark-ignition engines forms a promising approach to decarbonize hydrogen production and secure domestic energy supply. This study describes the development of an experimental setup for hydrogen production and testing a SI engine in the hydrogen-fueled mode. This paper investigates the effect of aluminum thickness (specific surface) and alkali concentration on the reaction rate. The experimental results show that an increase in alkali concentration and a reduction in aluminum thickness increase hydrogen production rate. The produced hydrogen was used as fuel for a single-cylinder spark-ignition engine. The experiments were conducted under various engine speeds. It is found that hydrogen combustion produces a lower exhaust gas temperature than gasoline, although $$\hbox {NO}_{{x}}$$ emissions decrease about 11 times compared to gasoline. It was expected that CO, $$\hbox {CO}_{2}$$ and HC levels are zero when the engine is supplied with hydrogen, but it is found that there is a slight trace of CO, $$\hbox {CO}_{2}$$ and HC due to combustion and evaporation of lubricant on cylinder walls.

Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine

The employment of aftertreatment systems in modern diesel engines has become indispensable to meet the stringent emissions regulations. However, a minimum exhaust gas temperature of approximately 200 °C must be reached to initiate the emissions control operations. Low-load engine operations usually result in relatively low exhaust gas temperature, which lead to reduced or no exhaust emissions conversion. In this context, this study investigated the use of different combustion control strategies to explore the trade-off between exhaust gas temperature, fuel efficiency, and exhaust emissions. The experiments were performed on a single-cylinder heavy-duty diesel engine at a light load of 2.2 bar indicated mean effective pressure. Strategies including the late intake valve closing timing, intake throttling, late injection timing (Tinj), lower injection pressure (Pinj), and internal exhaust gas recirculation and external exhaust gas recirculation were investigated. The results showed that the use of external exhaust gas recirculation and lower Pinj was not effective in increasing exhaust gas temperature. Although the use of late Tinj could result in higher exhaust gas temperature, the delayed combustion phase led to the highest fuel efficiency penalty. Intake throttling and internal exhaust gas recirculation allowed for an increase in exhaust gas temperature at the expense of higher fuel consumption. In comparison, late intake valve closure strategy achieved the best trade-off between exhaust gas temperature and net indicated specific fuel consumption, increasing the exhaust gas temperature by 52 °C and the fuel consumption penalty by 5.3% while reducing nitrogen oxide and soot emissions simultaneously. When the intake valve closing timing was delayed to after −107 crank angle degree after top dead centre, however, the combustion efficiency deteriorated and the HC and CO emissions were significantly increased. This could be overcome by combining internal exhaust gas recirculation with late intake valve closure to increase the in-cylinder combustion temperature for a more complete combustion. The results demonstrated that the ‘late intake valve closure + internal exhaust gas recirculation’ strategy can be the most effective means, increasing the exhaust gas temperature by 62 °C with 4.6% fuel consumption penalty. Meanwhile, maintaining high combustion efficiency as well as low HC and CO emissions of diesel engines.

低排出ガス温度・低濃度HC 条件において生成するディーゼル機関のEGR デポジット生成メカニズムの解析

低排出ガス温度・低濃度HC 条件において生成するディーゼル機関のEGR デポジット生成メカニズムの解析

Non-thermal-plasma-activated de-NOx catalysis.

The combination of non-thermal plasma (NTP) with catalyst systems as an alternative technology to remove NOx emissions in the exhaust of lean-burn stationary and mobile sources is reviewed. Several factors, such as low exhaust gas temperatures (below 300°C), low selectivity to N2 and the presence of impurities, make current thermally activated technologies inefficient. Various hybrid plasma-catalyst systems have been examined and shown to have a synergistic effect on de-NOx efficiency when compared with NTP or catalyst-alone systems. The NTP is believed to form oxygenated species, such as aldehydes and nitrogen-containing organic species, and to convert NO to NO2, which improves the reduction efficiency of N2 during hydrocarbon-selective catalytic reduction reactions. The NTP has been used as a pretreatment to convert NO to its higher oxidation states such as NO2 to improve NOx reduction efficiency in the subsequent processes, e.g. NH3-selective catalytic reduction. It has been applied to the lean phase of the NOx storage to improve the adsorption capacity of the catalyst by conversion of NO to NO2 Alternatively, a catalyst with high adsorption capacity is chosen and the NTP is applied to the rich phase to improve the reduction activity of the catalyst at low temperature.This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

Performance Analysis of Neem and Palm Bio-Diesel Blend on Diesel Engine - a Review

The objective of the present work is to study the effect of neem and palm oil biodiesel on the performance of the diesel engine. Different parameter testings and result formulations can be performed to enhance the different properties of additives poured in the diesel fuel. In the quest for renewable energy resource, efforts are made to find out options to alternative fuels. Blending of different vegetable based fuels has become a necessity and is gaining the attention of many researchers because the properties of the biodiesel prepared from vegetable oils are very close to those of diesel. In this work, the performance of the diesel engine is evaluated using hybrid biodiesel i.e. neem and palm oil biodiesel used as fuel. A comparative performance study gives the best blend for the diesel engine. The results show that engine performance, when fueled with biodiesel, has the same result that can be compared to petroleum fuel. B20 is found to be the best blend as it has the highest brake power and volumetric efficiency as well as higher break thermal efficiency and less emissions, compared to the other blends. Biodiesel is a good substitute for diesel and it is also more convenient over diesel for environmental reasons.In this review paper, an attempt is made to overview the research work done so far on non edible oil obtained from various blends and its performance in Diesel Engines. Biodiesel generally produces lower HC, CO and PM emissions compared to diesel. The cetane improver, which gives better Combustion characteristics, reduces the ignition delay and the maximum amount of fuel burnt nearer the TDC and no fuel remains for the after combustion stage or exhaust pipe combustion. Lower heating values give less heat generation, which causes lower exhaust gas temperature.

Effect of UWS injection at low exhaust gas temperature on NOx removal efficiency of diesel engine

Urea-SCR systems have been widely used in diesel vehicles according to the strengthened NOx (Nitrogen Oxides) emission standard. The NOx removal efficiencies of the latest well optimized urea-SCR system are above 90 % at moderate exhaust gas temperature of 250 ~ 450 °C. However, a large amount of NOx is emitted from diesel vehicles at cold start or urban driving conditions, when the exhaust gas temperature is not high enough for SCR catalyst activation. Although many researchs have been stuied to improve NOx conversion efficiency at these low temperature conditions, it is still one of important technical issues. In this study, the effect of UWS injection at low exhaust gas temperature conditions is studied. This study uses a 3.4 L diesel engine equipped with a commertial urea SCR system. As a result, it is found that about 5 % of NOx removal efficiency is improved in the NRTC test when UWS injection starts at the SCR inlet temperature of 150 °C compared to 200 °C. It is also found that urea deposits can be formed on the wall of exhaust pipe, when the local wall temperature is lower than temperature of urea decomposition.

A holistic investigation of natural gas\u2013diesel dual fuel combustion with dual direct injection for passenger car applications

This publication covers the investigation of a dual fuel combustion process for passenger car applications using natural gas and diesel as fuels. In the literature a widely studied dual fuel concept is the combination of port fuel injection of natural gas and direct injection of diesel. The challenge of this concept is a high emission of unburned hydrocarbons at low load operation as previous publications show. The proposed concept features a low pressure direct injection of natural gas in combination with direct injection of diesel to circumvent this problem. The acronym DDI—dual direct injection is introduced for this concept. It enables charge stratification of the air–natural gas mixture. This allows for a significant reduction of the unburned hydrocarbon emissions as earlier studies already demonstrated. The focus of this publication is on hardware variations which were performed on the engine test bench. Results are presented of a variation of the compression ratio and of different charge motion patterns which were studied. The results are compared with a conventional diesel and a gasoline spark ignited engine. The investigations demonstrate that a CO2 reduction of 20–29% is feasible as compared to conventional engines. Finally, investigations of exhaust gas aftertreatment with a three-way catalyst are published. The aftertreatment of the remaining engine-out hydrocarbon emissions is still the key challenge due to the low exhaust gas temperature during low load operation.

Analysis of upstream creeping reaction zones in catalytic monolith reactors

Monolith reactors are widely used in catalytic after-treatment systems (e.g. TWC, DOC, LNT and SCR). One major challenge in exhaust after-treatment is reducing cold-start emissions which account for a significant fraction of the total emissions. While front-end ignition is technically possible with high PGM loading and/or transient heating of the monolith, it may not be economical or feasible, especially for low exhaust gas temperature. In such cases, back-end ignition followed by a fast upstream creeping reaction zone provides a feasible way to reduce cold-start emissions. In this work, the upstream creeping reaction zone is investigated in detail using modeling approach. The influence of various design parameters (e.g. solid thermal conductivity and heat capacity) and operating conditions (gas velocity, inlet temperature/concentrations) on the creep velocity is determined and summarized. Phase diagrams and analytical criteria for reaction zones to creep upstream are also presented. The phase diagrams and criteria can provide guidance for design and control of reactors used in after-treatment systems.

Manipulating modern diesel engine particulate emission characteristics through butanol fuel blending and fuel injection strategies for efficient diesel oxidation catalysts

Decoupling the dependences between emission reduction technologies and engine fuel economy in order to improve them both simultaneously has been proven a major challenge for the vehicle research communities. Additionally, the lower exhaust gas temperatures associated with the modern and future generation internal combustion engines are challenging the performance of road transport environmental catalysts. Studying how fuel properties and fuel injection strategies affect the combustion characteristics, emissions formation and hence catalysts performance can unveil synergies that can benefit vehicle emissions and fuel economy and as well as guide the design of next generation sustainable fuels. The experimental work presented here was conducted using a modern single-cylinder, common rail fuel injection system diesel engine equipped with a diesel oxidation catalyst (DOC). The impact of the fuel post-injection strategy that is commonly used as part of the aftertreatment system function (i.e. regeneration of diesel particulate filters or activity in hydrocarbon selective reduction of NOX), combined with butanol-diesel fuel blend (B20) combustion on engine emissions formation, particulate matter characteristics (size distribution, morphology and structure) and oxidation catalyst activity were studied. It was found that post-injection produced lower PM concentration and modified the soot morphological parameters by reducing the number of primary particles (npo), the radius of gyration (Rg), and the fractal dimension (Df). The results were compared with the engine operation on diesel fuel. The increased concentration of HC and CO in the exhaust as a result of the diesel fuel post-injection at the studied exhaust conditions (i.e. T=300°C) led in the reduction of the DOC activity due to the increased competition of species for active sites. This effect was improved the combustion of B20 when compared to diesel.

Study of fuel inlet temperature variations on palm biodiesel operating with a diesel engine

Biofuel includes biodiesel is introduced to overcome the air pollution problems. Biodiesel is the sustainable and alternative fuel that derived from edible and non-edible oil produced from bio-originated species, plants, and animals. This paper presents the simulation analysis on the effect of fuel temperature variations on diesel engine performance and emission using palm-biodiesel. A one-dimensional numerical analysis, Diesel RK software is used to simulate a single cylinder, four-stroke diesel engine on the performance and emission when operated at a full load condition using fuel temperature variations ranging 300 K to 333 K. Results showed that simulated results for brake power and brake torque were 0.7% each when compared to the highest and lowest fuel temperature ranging from 333 K to 300 K. Moreover, higher fuel temperature for palm biodiesel tends to produce lower exhaust gas temperature and brake specific fuel consumption at a constant engine speed of 2400 rpm. It can be concluded that from the study, fuel temperature variations of biodiesel could produce a significant effect regarding engine performance and emission that influence the driving economy of the engine.

Comparative properties and utilization of un-preheated degummed/esterified mixed crude palm oil-diesel blends in an agricultural engine

The production, property, and utilization of un-preheated degummed/esterified mixed crude palm oil (DgMCPO/EMCPO)-diesel blends in an agricultural engine were studied. The results reveal that DgMCPO and EMCPO can be produced easily with costs comparable to diesel. They had a poor liquid phase and high viscosity. Through blending with diesel at maximum portions of 20 vol% (DgMCPO20) and 30 vol% (EMCPO30), clear liquid blends were produced. Almost important fuel properties of these blends met Thailand agricultural engine diesel standard with slightly higher densities and viscosities than diesel, significantly higher oxygen content than diesel, good cetane numbers, and slightly lower heating values than diesel. At 2200 rpm under loads in the range of 1.28–5.6 kW, un-preheated blends were able to well operate the engine as same as diesel. Comparing this with diesel; the blends resulted in slightly higher brake specific fuel consumptions (+4.5% and +5.0%), slightly lower brake thermal efficiencies (−0.9% and −1.2%), significantly lower levels of carbon monoxide (−33.7% and −33.2%), slightly lower exhaust gas temperatures (−5.1% and −5.5%), and significantly higher levels of nitrogen oxides (+8.9% and +15.9%); (all paired values, DgMCPO20 and EMCPO30 respectively). In conclusion, these blends are recommended as effective diesel substitutes for use in agricultural engines.

Cu-SSZ-13 as pre-turbine NOx-removal-catalyst: Impact of pressure and catalyst poisons

The development of highly efficient engines with lower exhaust gas temperatures leads to new challenges for catalysts in the aftertreatment system. One option for overcoming this is a catalyst positioned in front of the turbocharger with an exposure to higher temperature and pressure. The impact of increased pressure and typical catalyst poisons on the catalytic performance of a state-of-the-art Cu-SSZ-13 catalyst has thus been studied during the selective catalytic reduction of NOx with NH3. Various reactions including NO/NH3 oxidation, standard and fast SCR have been tested in a temperature range of 180–600°C. Propene as representative for small hydrocarbons and SO2 have been added under reaction conditions to analyze the direct influence at relevant reaction temperatures. An increased pressure resulted in a strikingly higher DeNOx-activity especially under Standard-SCR conditions, which was mainly due to higher NO oxidation to NO2 in the gas phase and a higher residence time. Even though propene led to a temporary competition between SCR-reaction and propene oxidation, the small decrease in DeNOx-activity can be overcompensated by the higher pressure and temperature within a pre-turbine configuration with no need for regeneration steps. In contrast, SO2 caused severe deactivation at low temperature but no influence at high temperature. Reactivation was not completely possible, which suggests some highly stable sulfur species. The higher pre-turbine temperature enables an earlier regeneration, showing a further advantage of pre-Turbo-SCR.

Potential of internal EGR and throttled operation for low load extension of ethanol–diesel dual-fuel reactivity controlled compression ignition combustion on a heavy-duty engine

High levels of carbon monoxide (CO) and unburnt hydrocarbon (HC) emissions are some of the main limitations of ethanol–diesel dual-fuel reactivity controlled compression ignition (RCCI) combustion at light engine loads. In addition, low exhaust gas temperatures reduce the effectiveness of the oxidation catalyst, necessary to meet stringent emissions standards. Elevation of in-cylinder gas temperature and increased fuel/air equivalence ratio are desirable to reduce the CO and HC emissions and hence improve combustion efficiency and fuel conversion efficiency. In this work, experimental studies and engine modelling have been carried out to investigate the potential of internal exhaust gas recirculation (iEGR) and throttled operation for low load extension of ethanol–diesel dual-fuel RCCI combustion. The experiments were performed on a single cylinder heavy-duty (HD) diesel engine equipped with a variable valve actuation system capable of intake valve re-opening during the exhaust stroke. The engine model was built in a one-dimensional computational fluid dynamics software. The utilisation of higher residual gas fractions and higher global equivalence ratios increased the mean in-cylinder gas temperatures during combustion. The hotter combustion processes resulted in lower CO and unburnt HC emissions, and higher exhaust gas temperatures. The lower oxygen concentration and higher heat capacity of the in-cylinder charge using iEGR curbed nitrogen oxides (NOx) formation. Net indicated efficiency was improved with the use of iEGR and remained nearly constant while throttling the engine when compared to the dual-fuel combustion baseline at 0.32MPa net indicated mean effective pressure (IMEPnet). Compared with conventional diesel combustion, ethanol–diesel dual-fuel RCCI combustion minimised NOx and soot emissions from 0.3 to 0.6MPa IMEPnet and increased efficiency at loads above 0.5MPa IMEPnet.

초희박 직접분사식 가솔린 엔진용 삼원촉매의 운전조건에 따른 배기저감 특성

Recently, because of the increased oil prices globally, there have been studies investigating the improvement of fuel-conversion efficiency in internal combustion engines. The improvements realized in thermal efficiency using lean combustion are essential because they enable us to realize higher thermal efficiency in gasoline engines because lean combustion leads to an increase in the heat-capacity ratio and a reduction of the combustion temperature. Gasoline direct injection (GDI) engines enable lean combustion by injecting fuel directly into the cylinder and controlling the combustion parameters precisely. However, the extension of the flammability limit and the stabilization of lean combustion are required for the commercialization of GDI engines. The reduction characteristics of three-way catalysts (TWC) for lean combustion engines are somewhat limited owing to the high excess air ratio and low exhaust gas temperature. Therefore, in the present study, we assess the reaction of exhaust gases and their production in terms of the development of efficient TWCs for lean-burn GDI engines at 2000 rpm / BMEP 2 bar operating conditions, which are frequently used when evaluating the fuel consumption in passenger vehicles. At the lean-combustion operating point, NO2 was produced during combustion and the ratio of NO2 increased, while that of N2O decreased as the excess air ratio increased.

An analysis of the thermodynamic efficiency for exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB)

This study presents fundamental research on the development of a new boiler that is expected to have a higher efficiency and lower emissions than existing boilers. The thermodynamic efficiency of exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB) was calculated using thermodynamic analysis and was compared with other boilers. The results show the possibility of obtaining a high efficiency when the temperature of the exhaust gas is controlled within 50–60 °C because water in the exhaust gas is condensed within this temperature range. In addition, the enthalpy emitted by the exhaust gas for the new boiler is smaller because the amount of condensed water is increased by the high dew-point temperature and the low exhaust gas temperature. Thus, the new boiler can obtain a higher efficiency than can older boilers. The efficiency of the EGR-CWR-WHR CB proposed in this study is 93.91%, which is 7.04% higher than that of existing CB that is currently used frequently.

Deactivation of Pd Catalysts by Water during Low Temperature Methane Oxidation Relevant to Natural Gas Vehicle Converters

Effects of H2O on the activity and deactivation of Pd catalysts used for the oxidation of unburned CH4 present in the exhaust gas of natural-gas vehicles (NGVs) are reviewed. CH4 oxidation in a catalytic converter is limited by low exhaust gas temperatures (500–550 °C) and low concentrations of CH4 (400–1500 ppmv) that must be reacted in the presence of large quantities of H2O (10–15%) and CO2 (15%), under transient exhaust gas flows, temperatures, and compositions. Although Pd catalysts have the highest known activity for CH4 oxidation, water-induced sintering and reaction inhibition by H2O deactivate these catalysts. Recent studies have shown the reversible inhibition by H2O adsorption causes a significant drop in catalyst activity at lower reaction temperatures (below 450 °C), but its effect decreases (water adsorption becomes more reversible) with increasing reaction temperature. Thus above 500 °C H2O inhibition is negligible, while Pd sintering and occlusion by support species become more important. H2O inhibition is postulated to occur by either formation of relatively stable Pd(OH)2 and/or partial blocking by OH groups of the O exchange between the support and Pd active sites thereby suppressing catalytic activity. Evidence from FTIR and isotopic labeling favors the latter route. Pd catalyst design, including incorporation of a second noble metal (Rh or Pt) and supports high O mobility (e.g., CeO2) are known to improve catalyst activity and stability. Kinetic studies of CH4 oxidation at conditions relevant to natural gas vehicles have quantified the thermodynamics and kinetics of competitive H2O adsorption and Pd(OH)2 formation, but none have addressed effects of H2O on O mobility.

Increased NO2 concentration in the diesel engine exhaust for improved Ag/Al2O3 catalyst NH3-SCR activity

Increasing the NO2 availability in some aftertreatment systems enhance their performance in reducing pollutants from internal combustion (IC) engines but result in significant fuel economy and CO2 emissions penalties. The presence of NO2 in the engine exhaust gas enhances the regeneration of the Diesel Particulate Filters (DPFs) and can improve the activity of the catalysts in reducing NOx emissions in the selective catalytic reduction (SCRs) process. In this work the production and the role of the increased NO2 concentration in the Ag/Al2O3 catalyst for the SCR process of NOx removal at low exhaust gas temperatures under real engine operation has been investigated. We have increased the NO2 concentration available for the SCR process with (i) the addition of different NH3 and H2 mixtures upstream the SCR catalyst and/or (ii) by the use of a Pt based Diesel Oxidation Catalyst (DOC) in front of the Ag/Al2O3-SCR catalyst. In the case of NH3 and H2 mixtures additions, H2 enhances the NO2 production on the Ag/Al2O3 catalyst, leading in promoting the “Fast-SCR” like reaction by utilising the available NH3 mainly at low reaction temperature. The incorporation of the DOC in front of the Ag/Al2O3 showed the same effect as it enhanced the NO2 availability for the SCR process.

Field test of coal type adaptability on a 300 MW CFB boiler

Coal type adaptability for CFB boilers is of great importance because it influences whether the unit can operate safely, economically and environmentally when the coal type is changed. Research is carried out on a 300MW CFB boiler located in Longyan power plant, Fujian province by burning three types of coal, i.e. Fujian anthracite, Shenhua bituminous coal and Indonesia lignite. The results show that all the three coals are capable to meet the basic requirement of bed temperature. But the fly ash carbon content and exhaust gas temperature depend on the coal type. Compared with Fujian anthracite, Shenhua bituminous coal and Indonesia lignite tend to possess lower fly ash carbon content and lower exhaust gas temperature under high boiler load, which helps to increase the boiler efficiency. The auxiliary power consumption rates under all the three types of coal are all lower than 4.3% with the successful utilization of lower energy consumption technology based on state specification design theory. Besides, when the fuel is changed from Fujian anthracite to Shenhua bituminous coal and Indonesia lignite, SO2 emission and dust emission decreases, while the NOx emission increases.

PROPERTIES AND PERFORMANCE OF E-BIODIESEL WITH CETANE IMPROVER ON VARIABLE COMPRESSION RATIO ENGINE

In the transport sector, a Major source of energy is from diesel engine. Karanja oils have a great potential to be alternative fuel for diesel engines. Use of non-edible oil is helpful for food security. Blend of biodiesel, ethanol and diesel fuel improve some properties compared with biodiesel diesel blends and ethanol biodiesel blends. Addition of ethanol (CN-6 to 8) lowers cetane number of blend with the addition of cetane improver it can be overcome. This paper consist of investigation of properties of karanja biodiesel, karanja biodiesel with 15% ethanol and cetane improver(3ml) and karanja biodiesel with 20% ethanol and cetane improver (3ml). Also the performance of these blends investigated with the help of variable compression ratio engine taking 15,16,17,18 as a compression ratio. Addition of cetane improver (2-EHN), lower ignition delay and improve combustion quality. The effect of these blends on Brake Specific Fuel Consumption (BSFC), Brake Thermal Efficiency (BTE), Indicated Thermal Efficiency (ITE), Volumetric Efficiency, Mechanical Efficiency, Exhaust Gas Temperature (EGT) is Studied. From experimental result it is found that additional lubricity gives better output with minimum frictional loss as compared with conventional diesel. Cetane improver which gives better combustion characteristics reduces ignition delay and maximum amount of fuel burnt nearer to TDC and no fuel remain for the after combustion stage or exhaust pipe combustion. Lower heating value give less heat generation which causes lower exhaust gas temperature.

Effect of biodiesel–butanol fuel blends on emissions and performance characteristics of a diesel engine

The purpose of this work is to investigate the effect of butanol–biodiesel blends on the emissions and performance characteristics of a four-stroke, naturally aspirated, water-cooled, indirect injection diesel engine (IDI). Testing was performed comparing butanol blended with biodiesel, standard diesel (D100) and neat biodiesel (B100) at four engine loads. The biodiesel–butanol blends were 5%, 10%, and 20% butanol in volume basis (B95Bu5, B90Bu10, B80Bu20). Compared to biodiesel, butanol blended fuels showed lower exhaust gas temperatures and nitrogen oxides (NOx) emissions while exhibiting higher carbon monoxide (CO) and unburned hydrocarbons (HC) emissions. Butanol blended fuels produced lower CO and higher NOx emissions than diesel fuel for low concentrations of butanol (5% and 10%), but there was no significant change in terms of HC emissions. The biodiesel blend containing the highest concentration of butanol (20%) caused higher CO and HC emissions and lower NOx emission than diesel. Brake specific fuel consumption increased with biodiesel and biodiesel blended fuels as compared to diesel.