Influence Of Exhaust Gas Recirculation Research Articles

Performance, emission, combustion, exergy, exergoeconomic and sustainability analyses of EGR incorporated CI engine fuelled with areca nut husk nano-additive dosed plastic oil–water-diesel emulsion blend

This first-of-a-kind research emphasizes the influence of exhaust gas recirculation (EGR) on engine characteristics, and exergy, sustainability, and exergoeconomic aspects of compression ignition engine, powered by plastic grocery bag-extracted plastic oil-diesel-water emulsion blend dosed with bio-nano-additive extracted from areca nut husk (D10EPO-15 ppm). Three EGR rates (5%, 10%, and 15%) were incorporated at varying engine loads. At 100% load, the EGR incorporation reduced the peak heat release rate and peak pressure up to 6.5 and 5.6%, respectively, in comparison to the base fuel without EGR. Up to 5.2 and 9.1% reduction in exhaust gas temperature and nitrogen oxide emission (NOx) was noticed with the EGR incorporation. However, carbon monoxide (CO), hydrocarbon (HC), and smoke emissions increased with the EGR incorporation. Nevertheless, considering the overall characteristics, 5% EGR was the most suitable one to have a lower NOx (3.4%) with a minimum penalty on CO (4.3%), HC (5.4%), and smoke (3.6%) emissions as well as fuel consumption (3%), at full load. Amongst the three EGR rates, 5% EGR incorporation also has the highest exergy efficiency (20.9%) and sustainability index (1.26). Exergoeconomic analysis also revealed the favorability of 5% EGR, and at full load, 5% EGR showed the lowest specific exergy cost inflow rate (0.8957 $/hr), the lowest specific exergy cost rate for shaft work (75.27 $/GJ), the lowest relative cost difference (3.99), and the highest exergoeconomic factor (9.95%).

Impact of exhaust gas recirculation and nitric oxide on the autoignition of an oxygenated gasoline: Experiments and kinetic modelling

Exhaust gas recirculation (EGR) and NOx affect the autoignition of gasoline in internal combustion engines. In this work, ignition delay times of an oxygenated gasoline (Euro 6 E10) are investigated with EGR and NOx addition. The experimental data are of interest for gasoline surrogate modeling and for predicting fuel ignition behavior in various engine combustion modes. We studied Euro 6 E10 reactivity with EGR additions of 20 % and 40 % (by mass) doped, in select cases, with high levels of NOx (874, 1501, 3174, and 5568 ppm, by mol%). Experiments were performed in two high-pressure shock tubes (HPSTs) and two rapid compression machines (RCMs) over a wide range of temperature (658–1610 K), equivalence ratio (0.5, 1.0) and at pressures of 20 and 30 bar. Results show that EGR addition inhibits Euro 6 E10 gasoline reactivity in the intermediate- and low-temperature regimes, while it is minimally affected at high-temperatures. In contrast, a strong reactivity-promoting effect of NOx is observed at temperatures greater than 825 K for all equivalence ratios investigated, while an inhibiting effect is seen at lower temperatures with a high doping of NOx (1501 ppm). For fuel-lean cases, where Euro 6/EGR mixtures are sensitized with 3174 – 5568 ppm NOx, a significant reactivity-promoting effect is observed across the entire range of conditions investigated, except at temperatures below 830 K, where the NOx-inhibiting effect dominates. A gasoline surrogate model is developed by combining a detailed gasoline surrogate mechanism with appropriate sub-models and making minor updates. The proposed model captures well the influence of EGR and EGR/NOx on Euro 6 E10 autoignition over the wide range of conditions studied here. Finally, sensitivity analyses were conducted to identify key reactions contributing to the perturbative effects of EGR and EGR/NOx on oxygenated gasoline ignition.

Quantification of φ-operating range with impact of exhaust gas recirculation under low-temperature combustion mode with polyoxymethylene dimethyl ether: A perspective study

Low-Temperature Combustion (LTC) especially Homogeneous charge compression ignition (HCCI) mode of combustion is a capable substitute mode of combustion to conventional diesel combustion (CDC) to provide better soot-NOx trade-off and HC-CO trade-off characteristics. The current study mainly focuses on the Exhaust Gas Recirculation (EGR) effects and equivalence ratio optimization on W20P20 (64% diesel, 16% WCO biodiesel, and 20% PODE) fuel along with exergy analysis in the HCCI mode of operation. The reason for inculcating exergy analysis in this research is to depict that low-temperature combustion provides a better heat transfer rate inside the cylinder. EGR has been varied in terms of 10%, 20%, and 30% in volume proportions along with the inlet fuel-air mixtures since, the fuel was injected through a pilot fuel injector in the inlet manifold. A novel factor in this research is considering both soot-NOx and HC-CO trade-off characteristics in optimizing the equivalence ratio with the influence of EGR over W20P20 fuel. The performance parameters such as BTE and BSEC show a mere decrement of about 6.67% and 29% of maximum with the influence of EGR while better combustion was found in terms of avoiding misfiring at a low equivalence ratio of 0.29–0.35 and knocking at a high equivalence ratio of 0.61–0.71 for W20P20 fuel. The operating range extension of the equivalence ratio was found with W20P20 fuel which further increased again with the increase in EGR addition. The emission limits of soot, NOx, CO, and HC particles were analyzed, in which the highest NOx reduction of 53% was obtained with 30% EGR irrespective of the equivalence ratio. The highest soot reduction was 61.85% with 20% EGR at a higher equivalence ratio. The highest HC reduction was 18% with 20% EGR at a lower equivalence ratio. The CO emissions seemed to reduce by 12% at a lower equivalence ratio while they increased by 47% at a higher equivalence ratio. The comparative results were studied for EGR influence with W20P20 fuel in the HCCI mode of combustion.

Influence of exhaust gas recirculation on working characteristics of biodiesel operated in LHR diesel engine

Influence of exhaust gas recirculation on working characteristics of biodiesel operated in LHR diesel engine

Numerical investigation of combustion characteristics of a single-cylinder linear engine fueled by natural gas under the influence of exhaust gas recirculation

The effect of applying the exhaust gas recirculation technique on the performance of a free-piston engine, including the resulting emissions, is introduced and assessed in this study. The simulation process has been performed over a single-cylinder, two-stroke free-piston engine that uses a homogeneous charge compression ignition. Two main sub-models that work implicitly to simulate the engine performance and emissions in an iterative simulation procedure using MATLAB® and Cantera toolbox. It was found that recycling a small percentage of the exhaust gases (∼10%) has a significant effect on reducing the engine emissions, like the NO x levels. Four different levels of EGR were applied in the simulations at , , and . Raising the percentage of the recirculated gases beyond a specific threshold will encounter a negative outcome by increasing the emissions of other particles, such as the UHC and CO. Moreover, it can lower the oxygen (O2) concentrations causing an incomplete fuel–air burning which reduces the combustion efficiency. The recirculation of 30% of the exhaust gases was aggressively able to reduce about 14 g/kWh of NO x at the ignition time compared to no recirculation, and about 8 g/kWh at the steady state.

Exhaust gas recirculation effects on flame heat release rate distribution and dynamic characteristics in a micro gas turbine

Exhaust gas recirculation (EGR) is an option proposed to augment the CO2 content in the exhaust gas for the efficient removal of CO2. In the field of micro-gas turbine (MGT), EGR is also a feasible solution to improve the part-load performance and fuel flexibility. This research combined EGR with an adjustable fuel feeding combustor to assess the part-load performance of a 300 kW MGT and the flame spatiotemporal characteristics. The radical chemiluminescence intensity of hydroxyl is selected to represent the heat release rate (HRR) in natural gas flames. The influence of EGR on HRR was investigated experimentally under various load ratios (50%–100%) and EGR ratios (0–20%). In addition, the temperature at the combustion chamber outlet is also measured. The results show that EGR can effectively reduce OTDF when the load ratio is high. Both the spatial distribution non-uniformity and fluctuation amplitude of HRR are suppressed after applying EGR. And EGR can also reduce the influence of mixing on HRR spatiotemporal characteristics. At last, the frequency characteristics of HRR are analyzed. The result shows that the flame frequency has a strong correlation with the characteristic frequency of turbulence.

Influence of Exhaust Gas Recirculation on Performance, Combustion, and Emission Characteristics of a Common Rail Direct Injection Diesel Engine Fueled by Diesel/Higher Alcohol Blends

Abstract Emission and combustion parameters of common rail direct injection combustion engine with different proportions of exhaust gas recirculation (EGR) rate and long-carbon-chain alcohol blends on performance are the main motive of this research. To lessen the dependency on diesel fuel and reduce harmful emissions, 1-hexanol is used, as it has better fuel properties than small-carbon-chain alcohol, and it can be blended with diesel. In common rail direct injection combustion engine, research was conducted, in which fuel blends (1-hexanol-diesel) were variant, i.e., (10%, 20%, 30%) by volume whereas engine speed was fixed at 1500 rpm by varying the load at 25% step from 25 to 100%. Blends were examined with various exhaust gas recirculation rates (10 and 20%) to see what impact they have on engine properties. It was observed that the higher the proportion of 1-Hexanol, the lower the engine performance. The research revealed that for the blend D70H30, around 8.24% rise in brake specific fuel consumption, slight rise in hydrocarbon, 2.80% reduction in brake thermal efficiency (BTE), and 16.70% reduction in nitrogen oxides (NOx) emission. With 1-hexanol-diesel blends, the engine is noted to function effortlessly, so as a substitute to the diesel upto 30% of the 1-hexanol can be used while increasing the total cost of implementation. Increase in hexanol and EGR percentage shown negative impact on the brake thermal efficiency, HC and CO emission however, NOx and CO2 emissions were found to be decreased.

An experimental investigation into the soot particle emissions at early injection timings in a single-cylinder research diesel engine

Engine experiments were performed to examine the effect of early-injection on smoke emissions and engine performance under typical low temperature combustion (LTC) and reactivity controlled compression ignition (RCCI) operating conditions. On that basis, the influence of exhaust gas recirculation (EGR), intake pressure, fuel properties and fuel injection strategy on the engine-out soot emissions at early injection timings was also assessed. At last, the morphology, nanostructure characteristics of exhaust soot particles were analyzed. The test results showed when the injection timing was advanced before −30° crank angle after top dead center (CA ATDC) and earlier, the fuel spray impinged onto the piston crown surface, and a part of fuel entered into the squish zone and expanded to reach the cylinder liner wall and entered into the crevice volume, leading to a continuous increase in soot emissions, the peak smoke emission was found to occur at −55° CA ATDC. By adopting fuels with high volatilities and a RCCI fuel delivery strategy, soot emissions can be effectively reduced at early timings. Most of the high-resolution transmission electron microscopy (HRTEM) images of the sampled soot particles showed small spherical particles with a wide range of size distribution connected, and “onion-like” fringe arrangement was found in most of the images. As the fuel injection timing was retarded from −55° to −35° CA ATDC, the samples exhibited more highly organized carbon nanostructures; the fringe tortuosity and separation distance increased, while the fringe length decreased. The formation of more ordered arrangement of graphene layers led to significant resistance to oxidation.

The influence of exhaust gas recirculation on the characteristics of compression ignition engines powered by tamanu methyl ester

Abstract This study aims to assess the performance of compression ignition (CI) engine powered with various biodiesels. The engine used for this test was a single-cylinder, water-cooled, naturally aspirated, CI engine. The biodiesels used in this study were neem methyl ester (NME), mahua methyl ester (MME), cottonseed methyl ester (CME), tamanu methyl ester (TME) and Albizia saman methyl ester (AME). According to the results, the TME-operated CI engine had 2.69%, 10.53%, 6.31% and 5.49% higher brake thermal efficiency than the MME, NME, CME and AME, respectively, without exhaust gas recirculation (EGR). Tamanu biodiesel outperformed the other test fuels in terms of performance and emissions. As a result, tamanu biodiesel was chosen as the best fuel for further testing. The results showed that tamanu biodiesel emitted more oxides of nitrogen (NOx) emissions than diesel. EGR could be used with the CI engine, resulting in a significant reduction in NOx emission. Compared to tamanu biodiesel without EGR conditions, the percentages of EGR 5%, 10% and 15% used with TME-operated CI engine produced 9.9%, 18% and 21.3% less NOx emission. The combination of EGR and tamanu biodiesel resulted in a slight increase in hydrocarbon, smoke and carbon monoxide emissions but a substantial reduction in NOx emissions. According to the study’s findings, tamanu biodiesel with 10% EGR demonstrated optimal engine characteristics while having a low environmental impact.

Calculation studies of the influence of exhaust gas recirculation on the characteristics of the natural gas-fueled diesel engine

When converting diesel engines to run on natural gas on the gas-diesel cycle, additional problems arise associated with the high thermal stress of the exhaust valves and valve seats at high loads and engine speeds. There is also an increase in NOx emissions due to higher combustion temperatures of natural gas. One of the ways to improve the economic and environmental performance of engines operating on a gas-diesel cycle with a lean air-fuel mixture is to optimize the combustion of the air-fuel mixture by using an exhaust gas recirculation system (EGR). The principle of operation of this system is as follows: exhaust gas entering the intake manifold and further into the combustion chamber reduces the oxygen concentration in the air-fuel mixture, which leads to a dilution effect and, accordingly, to a decrease in combustion temperature and a decrease in NOx content. In order to study the influence of EGR on the dual-fuel gas and diesel engine parameters in the AVL Boost software package, a computer model of the existing 6ChN13/15 engine was developed. A low-pressure EGR system with an exhaust gas cooler was simulated on this engine. Values of NOx emissions, brake specific fuel consumption (BSFC) and brake efficiency have been obtained at different recirculation rate by calculation method. These values allow to estimate the feasibility of using a cooled EGR in a natural gas-fueled diesel engine.

Influence of EGR on a CI engine running on 20% blend of jatropha biodiesel

Abstract Biodiesels are becoming famous as an elective fuel due to their emission qualities. But still, there are some issues with the exhaust emission from biodiesel. The emission like CO, HC and CO2 reduces with biodiesel, but the NOx outflow increases with biodiesel. The present study involves the application of exhaust gas recirculation (EGR) to diminish NOx. The J20 (20% blend of Jatropha biodiesel) is utilised as a fuel in a CI engine for this investigation. The emissions like CO, HC, CO2 and NOx and 20% EGR are noted down at 10% and 20% EGR. The load is varied from 0% to 100%. The NOx is reduced significantly, but the CO, CO2, HC and smoke increases on applying Exhaust Gas recirculation (EGR).

Investigation on the performance, emissions and combustion characteristics of CRDI engine fueled with tallow methyl ester biodiesel blends with exhaust gas recirculation

This paper demonstrates the study of performance, combustion and emission characteristics of a common rail diesel injection (CRDI) engine with the influence of exhaust gas recirculation (EGR) (5, 15 and 25%) at various fuel injection pressures (400, 500 and 600 bar) under the effective load conditions (0, 25, 50, 75 and 100%). The experiments were carried out in a controlled manner using the CRDI engine fuelled with 80% (D80) diesel (98% purity) blended with 20% (B20) tallow biodiesel. The engine has been operated at a rated speed of 1500 rpm on all load conditions, fuel injection timings of 10°, 15° and 20° bTDC, fuel injection pressures of 400, 500 and 600 bar, respectively. Combustion-influenced performance characteristics such as variation of in-cylinder pressure and net heat release rate in J deg−1 are also studied with the above operating conditions. It was observed that the usage of 20% biofuel blend shows considerable improvement in combustion, and it further enhances with an increase in the injection pressures. Besides, EGR (up to 25%) reduced significant pollutants at higher operating pressures (600 bar) at higher load conditions. It was also observed that CO2 emission increased with increase in the % EGR with an increase in the load conditions. However, for CO emission increased up to 50% load condition and subsequently tends to decrease due to improved combustion at higher load; hence higher temperature. NOx, smoke opacity continue to increase with the increase in pressure and the percentage increase in EGR due to its attainment of adiabatic temperature, which leads to the pathway for the Zeldovich mechanism. The present work shows light on the usage of tallow methyl ester produced from the wastes in the tannery industry as alternate biofuel operating the CRDI engines without compromising its combustion and emission characteristics to deliver the same power as petro-diesel.

Experimental analysis of a mini truck CRDI diesel engine fueled with n-Amyl alcohol/diesel blends with selective catalytic reduction (SCR) as a DeNOx technique under the influence of EGR

ABSTRACTThe current work aims to investigate the compatibility of n-Amyl alcohol in a mini-truck common rail direct injection (CRDI) compression ignition (CI) engine with exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) as a DeNOx technique. The n-Amyl alcohol is a renewable biofuel it effectively mitigates the demand for fossil fuels and reduces greenhouse gas emission. Palladium and Rhodium coated SCR catalyst was used to reduce the nitrogen oxides (NOx) emission. For SCR of NOx ammonia was used as a reductant. From the experimental results, it was noted that with an increase in the percentage of alcohol in the blends, a slight drop in brake thermal efficiency (BTE) and higher brake specific energy consumption (BSEC) was observed. Both NOx and hydrocarbon (HC) emissions could be reduced with the use of n-Amyl alcohol and a combination of SCR and EGR techniques. The maximum reduction of NOx can be successfully achieved with the use of 40N60D (40% n-Amyl alcohol & 60% Diesel v/v) blend with SCR and 20% EGR at the slight cost of BTE. The engine can be successfully worked up to 40% of n-Amyl alcohol/diesel blends without causing any visible damage to the engine, with less NOx emissions. It is concluded that n-Amyl alcohol will be a sustainable next-generation biofuel for commercial vehicles.

Information and analytical system to monitor operating processes and environmental performance of vehicle propulsion systems

The article describes the peculiarities of using the information and analytical system to study the operating processes of vehicle propulsion systems and to assess their environmental performance, particularly fuel consumption and harmful emissions under operating conditions. The study provides the functional structure of the information and analytical system. It contains the subsystems that enable to obtain and analyze data about the operating process in the cylinder, the subsystem for obtaining data from the engine control system, the subsystem for obtaining data about the operating mode of the propulsion system, the subsystem of data analysis and forecasting the vehicle propulsion system indicators in different operating modes. The case of using the information and analytical system has been shown to study the influence of exhaust gas recirculation on fuel efficiency and environmental performance indicators of the vehicle propulsion system in separate modes and under operating conditions.

Effect of n-pentanol additive on compression-ignition engine performance and particulate emission laws

Biodiesel has a high viscosity, which limits its application to engines. However, n-pentanol has low viscosity and high volatility, which is considered a promising additive. This study examined the influence of n-pentanol/biodiesel/diesel blends on the performance and particulate emissions of a diesel engine at different loads, under the condition of coupling exhaust gas recirculation (EGR) (0–30%). The three test fuels included pure diesel (D100); 80% diesel and 20% biodiesel blended fuel (BD20); 64% diesel, 16% biodiesel, and 20% n-pentanol blended fuel (BDP20). The results indicated that the influence of EGR on the NOx emissions between fuels was greater than that of the physicochemical properties of the fuels. For the same EGR rate, the heat release rate (HRR), peak in-cylinder pressure (IP), and brake thermal efficiency (BTE) increased with the engine load increased. After adding n-pentanol to BD20, the HRR increased. The peak IP and BTE values of BDP20 were similar to those of D100 and BD20. With the addition of n-pentanol, the total particulate number concentration (TPNC), soot, and total particulate mass concentration (TPMC) emissions decreased. Furthermore, the trade-off relationship between TPMC and NOx was improved, and the geometric mean diameter (GMD) of the particles decreased.

Influence of Exhaust Gas Recirculation on Dairy Scum Biodiesel Operated Diesel Engine Performance

Effort towards prospective utilization of dairy waste scum oil methyl ester (DSOME) is extremely pronounced as a promising sustainable unconventional fuel for diesel engine as they have intrinsic oxygen content emits less HC and CO emission and contradictorily increases the NOx. In this regard, the present study elucidates the influence of engine exhaust gas recirculation (EGR) on diesel engine performance, combustion and emission characteristics operated with DSOME-B20 (20% dairy scum biodiesel, by volume). The brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) are appreciably improved for 5% and 10% EGR in comparison with 15% EGR rate. Mainly, about 49-57% of NOx can be reduced with 5-15% EGR rate but increasing EGR rate more than 10% dilutes the fresh intake air hence reduces the NOx and increases the HC, CO emissions. Hence use of 5-10% EGR in diesel engine is advantageous to get considerably improved performance and reduced HC, CO and NOx emissions.

Effects of EGR rates on combustion and emission characteristics in a diesel engine with n-butanol/PODE3-4/diesel blends

An experimental investigation is conducted on the influence of EGR (Exhaust Gas Recirculation) rates (0–40%) on the combustion and emission characteristics of n-butanol/diesel/PODE3-4 blends at low-temperature combustion mode in diesel engine. The results show that at identical EGR rate, compared to D100 (diesel fuel), the peak values both of the mean cylinder pressure and the heat release rate of BD20 (20% butanol and 80% diesel in volume) are increased, ignition delay is extended, and the brake thermal efficiency is enhanced. Concerning BD20 blended with PODE3-4, the ignition delay is shortened, while both the brake thermal efficiency and the combustion efficiency increase. At the EGR rate below 30%, as the EGR rate grows, the effects on emission of soot, CO and HC are not significant, while the emission of NOx is sharply reduced; when the EGR rate is above 30%, as it grows, the emissions of soot, CO, and HC drastically rise. As EGR rate grows, the total particulate matter (PM) number concentrations of four fuels firstly decline and then rise, the total PM mass concentrations keep stable firstly and then rise drastically. As the proportion of added PODE3-4 in BD20 grows, the particle geometric mean diameters further decrease.

Experimental study on knock sources in spark ignition engine with exhaust gas recirculation

The presented study aims to experimentally investigate the sources of influence of exhaust gas recirculation on the tendency toward knock in the spark ignition engine. The three main sources of influence of exhaust gas recirculation on the engine tendency towards knock are known. The influence on flame propagation changes the profile of combustion and therefore the end-gas pressure and temperature profile. The thermal influence changes the thermal properties of the end-gas mixture and consequently its temperature profile, while the chemical influence changes the kinetic behaviour of the end-gas mixture. The study is based on the results from experimental setup with spark ignition engine that uses cooled exhaust gas recirculation system and air heater installed into the intake manifold. Experimental tests that employ a new approach were performed, where intake temperature is varied by air heater when engine is operated with different levels of exhaust gas recirculation. In this way the end-gas temperature and exhaust gas recirculation percentage were varied while the influence on flame propagation was partially compensated by the change of spark timing. The obtained results show that there is no clear chemical influence of the exhaust gases on the tendency towards knock as the cases with low and high levels of exhaust gas recirculation are all mixed when the temperature of the end-gas is set to the same values. This leads to the overall conclusion that the predominant factor in a tendency towards knock is the end-gas temperature profile.

Influence of EGR on the simultaneous reduction of NOx-smoke emissions trade-off under CNG-biodiesel dual fuel engine

Dwindling fossil fuel resources and deteriorating ambient air quality has mandate the search for suitable alternative fuels for diesel engine. Dual fuel engines show remarkable engine performance characteristics at higher engine loads but suffer from high NOx-smoke opacity emissions trade-off. In the present study, an attempt has been made to introduce exhaust gas recirculation (EGR) under compressed natural gas (CNG) fuelled diesel engine using Jatropha biodiesel (B20) blend as pilot fuel. Experimental investigations were carried out in a single cylinder direct injection compression ignition engine, which was suitably modified to operate under dual fuel mode along with EGR. Comparative analysis was made on the basis of combustion, performance and emissions characteristics at different engine operating loads for fossil diesel, CNG and biodiesel blend (B20) with and without EGR. It was evident from the experimental investigations that dual fuel mode with EGR improved the NOx-smoke emission trade-off at higher engine loads without deteriorating engine combustion and performance characteristics.

Effect of exhaust gas recirculation on performance and emission characteristics of a diesel engine fuelled with tamarind biodiesel

ABSTRACTThe present research work focuses on the influence of exhaust gas recirculation (EGR) on the characteristics of the diesel engine operated with 20% tamarind seed methyl ester (TSME 20) as the renewable fuel. The use of TSME 20 as biodiesel results in closer performance characteristics with diesel fuel. However, TSME 20 biodiesel blend generated higher oxides of nitrogen (NOX) emissions at all operating conditions. Firstly, tests are performed using diesel and TSME 20 biodiesel blend at constant speed under different loads. Thereafter, experiments are conducted on TSME 20 with EGR rates at different concentrations. The test results revealed that with TSME 20 with 20% EGR rate, NOX emissions are reduced by 45.67% and 52.69% when compared to diesel and TSME 20. However, there is a slight reduction in brake thermal efficiency. Hence, the use of 20% EGR rate to TSME 20 is an optimum approach for better control of NOX emissions.Abbreviations BDC: bottom dead centre; BMEP: brake mean effective pressure; BSFC: brake-specific fuel consumption; BTE: brake thermal efficiency; CO: carbon monoxide; CO2: carbon dioxide; EGR: exhaust gas recirculation; FSN: filter smoke number; HC: hydrocarbon; kWh: kilo Watt hour; NOX: oxides of nitrogen; ppm: parts per million; SO: smoke opacity; TDC: top dead centre; TSME: tamarind seed methyl ester; TSME 20: 20% tamarind seed methyl ester; TSME 20–20%: tamarind seed methyl ester with 80% diesel; TSME 10% EGR: TSME 20 with 10% exhaust gas recirculation; TSME 20% EGR: TSME 20 with 20% exhaust gas recirculation; TSME 30% EGR: TSME 20 with 30% exhaust gas recirculation