Hot Exhaust Gas Recirculation Research Articles

Comprehensive Analysis of Compression Ratio, Exhaust Gas Recirculation, and Pilot Fuel Injection in a Diesel Engine Fuelled with Tamarind Biodiesel

The global automotive industry is facing significant challenges, including dwindling fossil fuel reserves, rising crude oil prices, and increasingly strict emission regulations. To address these concerns, this study investigates the impact of the compression ratio (CR) and exhaust gas recirculation (EGR) on the performance and emissions of a common rail direct injection (CRDI) diesel engine fuelled with a 20% blend of tamarind seed methyl ester (TSME 20) biodiesel. The study employed an open-type electronic control unit to implement pilot fuel injection at a rate of 30%, 23° before the top dead centre (TDC), and at a higher pressure of 600 bar. Three CRs (16:1, 18:1, 20:1) and two types of EGR (hot and cold EGR at 10%) were evaluated. Diesel fuel at CR 18 was used as a baseline for comparison. The experimental procedure involved conducting tests with TSME 20 at CR 16, 18, and 20. Subsequently, TSME 20 at CR 20 + Hot EGR 10% and TSME 20 at CR 20 + Cold EGR 10% were examined. The results showed that TSME 20 operated at a higher CR (CR 20) exhibited improved diesel engine performance and significant reductions in harmful exhaust emissions. Additionally, cold EGR at 10% was more effective in reducing CO, CO2, and NOx emissions from TSME 20 than hot EGR. The findings of this study provide valuable insights into optimizing diesel engine operation to achieve a balance between performance enhancement and emission reduction through tamarind seed biodiesel blends and different EGR techniques. The implementation of these strategies holds considerable potential in addressing the automotive industry’s challenges, including ecological considerations and fuel price fluctuations.

Evaluation of energy-exergy performance and sustainability index of a DI engine integrated with designed electromechanical EGR cooling system

Exhaust Gas Recirculation (EGR) system is a commonly used pretreatment technique to improve pollutant emissions from modern diesel engines. Recently, the EGR cooling strategy focuses on improving combustion stability, NOx emission and fuel consumption values by controlling oxygen dilution, in-cylinder and exhaust gas temperatures. However, there are not enough studies focusing on energy and exergy analysis to improve the deterioration caused by hot EGR gas in engine performance and energy distributions. Therefore, in this study, classical and electronically controlled external EGR cooling systems are designed. The present study investigates the effect of the various EGR rates and EGRout gas temperatures on classical/electromechanics EGR cooling systems in a DI diesel engine and reveals the effects of energy-exergy distributions on each other and the sustainability index (SI) perspective. The tests are performed with various EGR rates (5%, 10%, 15%) and EGRout gas temperatures (75 °C, 90 °C, 110 °C) at 1700 and 2000 rpm. At 1700 rpm test conditions, the highest thermal-exergetic efficiencies for low and high load are recorded at 15% EGR rate-75 °C EGRout gas temperature and 5% EGR rate-75 °C EGRout gas temperature, respectively. At 2000 rpm test conditions, the highest thermal-exergetic efficiencies for low and high load are achieved at 15% EGR rate-110 °C EGRout gas temperature and 5% EGR rate-90 °C EGRout gas temperature, respectively. The main findings show that the EGR rate rather than the EGRout gas temperature has a more dominant effect on the in-cylinder combustion performance and thermal-exergetic efficiency. While the increase in the EGR rate from 5% to 15% contributes positively to the thermal-exergetic efficiency and SI performance at low engine load, the opposite is observed at high load. The study recommends that the EGR rate and EGRout gas temperature should be chosen at the optimum level for the engine performance and energy efficiency.

Gasoline compression ignition (GCI) combustion in a light-duty engine using double injection strategy

Controlling the oxides of nitrogen (NOx) and particulate matter (PM) emissions is one of the vital goals of compression ignition (CI) engines. Implementing stringent emissions regulations has motivated researchers to adopt various strategies for controlling emissions. Gasoline compression ignition (GCI) has emerged as a prime technology to control emissions and increase engine efficiency, while using low-octane gasoline as fuel in CI engines. Preheated air, hot exhaust gas recirculation (EGR), and negative valve overlap, are required to manage the combustion instabilities in the GCI engines. However these techniques have not been used in this study in order to reduce system complexity. Low octane test fuel was prepared (G80) by blending 80 % v/v gasoline and 20 % v/v diesel. This study involved experiments to evaluate the effects of main injection timing, split injection quantities (10–30 %), and engine load (brake mean effective pressure (BMEP): 3–5 bar) on a two-cylinder GCI engine’s performance, combustion, cyclic variability, emissions, and particulates. Conventional diesel combustion (CDC) mode experiments were performed using diesel. The results indicated a 5 % higher brake thermal efficiency (BTE) and comparable exhaust gas temperature (EGT) for the GCI mode compared to the baseline CDC mode. GCI combustion with low split ratio showed higher in-cylinder pressure than CDC mode. Baseline CDC mode showed < 3 % coefficient of variation of indicated mean effective pressure and peak pressure, whereas these parameters varied from 1 % to 9 % in the GCI mode. GCI mode engine exhibited ∼ 60 and 50 % lower NOx and PM emissions than baseline diesel mode engine. The double injection strategy improved GCI engine's performance and emission characteristics.

Impacts of using EGR and different DI-fuels on RCCI engine emissions, performance, and combustion characteristics

• EGR contributed to further reductions in NOx emissions in RCCI combustion. • Improvements in BTE and BSFC were achieved by using EGR in RCCI combustion. • Better RCCI operation with EGR requires an alternating premixed fraction. • Increased biodiesel dose in DI-Fuel lead to an increment in NOx emissions. Exhaust gas recirculation (EGR) seems to be a critical parameter in developed RCCI operations for controlling emissions, in-cylinder charge reactivity as well as combustion phasing. The most advantages of utilizing the RCCI burning technique are the simultaneous decrease of PM as well as NOx emissions. Nevertheless, significant challenges remain, such as extreme HC and CO emissions. The purpose of this work is to investigate the effects of external, hot, and high-pressure EGR as well as different DI-Fuels on RCCI combustion under various load conditions. The tests were performed on direct injection, single-cylinder, and four-stroke modified diesel engine (peak power 5 KW under 1500 rpm) operating in RCCI mode with an EGR system. To initiate ignition, high reactivity fuel (biodiesel/diesel blends) was injected directly inside the engine's cylinder whereas low reactivity fuel (LPG) was induced into to intake mixing chamber. EGR at various ratios (30%, 20%, and 10%) was introduced into the engine via the intake mixing chamber, and experiments were done under various loads. The results show that increasing EGR results in a slight increment in BTE under medium and high engine loads. NOx emissions from diesel engines operating in traditional RCCI mode declined dramatically, and they decreased even further with the addition of EGR. The CO and HC emission levels, on the other hand, are slightly greater when EGR is used. Increasing the proportion of biodiesel in DI-Fuel is resulting in a decrement in BTE and NOx emissions in addition to an increment in BSFC, CO, and HC emissions.

Impacts of EGR on RCCI engines management: A comprehensive review

• Benefits and drawbacks of EGR on RCCI engine management are discussed. • EGR has a great impact on the RCCI engine's emission and performance characteristics. • The higher EGR percentage has more benefits on lowering soot and NOx emissions. • The collaborated regulation is important between EGR, premixed ratio, and DI timing. Exhaust gas recirculation (EGR) has been one of the essential aspects to manage combustion phasing, in-cylinder reactivity, performance, and emissions in innovative RCCI engine operation. In this review, the effect of EGR on RCCI engine operations is reviewed and different techniques to employ EGR are discussed. Generally, RCCI engine operation needs EGR support, especially at high engine loads to limit the pressure increase rate, and around 50 percent of EGR may be essential based on fuel used and engine load. The RCCI combustion engine needs a substantially low EGR rate since the rate of burning is regulated by altering the mixture reactivity by employing two fuels having significantly varied reactivity. RCCI operation with cooled EGR yielded lower pressure rise rate, cyclic variation, and NOx emissions but greater THC emissions than hot EGR operation. Internal EGR and lower pressure of intake air achieved generally greater net indicated efficiencies and reduced emissions than that of the conventional RCCI combustion at low loads. At high load, the internal EGR mode is required to be turned off to minimize fuel efficiency loss. The higher EGR percentage has more benefits on extending maximum load and lowering soot and NOx emissions, whereas the combustion and indicated thermal combustion efficiencies decline to utilize higher EGR percentage. Thus, to accomplish the greater performance and efficient process of combustion, the collaborated regulation is important between EGR rate, premixed ratio, and direct-injection timing.

Comparative analysis on single, double and triple fuel injection strategy of single cylinder RCCI engine fueled with ethanol-gasoline/diesel-biodiesel blends

This experimentation attempts to investigate the parametric and comparative analysis of single, double and triple injection strategies of DI (direct injection) for modified constant speed non road single cylinder RCCI engine. The blends of ethanol-gasoline and diesel- jatropha biodiesel were used as a low reactivity fuel (LRF) and high reactivity fuel (HRF), respectively. The ratio of LRF and HRF was 60:40. The following parameters were employed in this experiment: 12% hot exhaust gas recirculation (EGR), 3 bar PFI (port fuel injection) pressure, and 500 bar HRF injection. In the case of single injection strategy, injection timing was −25 deg atdc with 100% mass, for double injection strategy −40 deg and-18 deg atdc with 40% and 60% mass and triple injection, −31 deg, −21 deg and −11 deg atdc with 30%,30% and 40% masses respectively. All the tests were performed at 1500 rpm speed and under various loading conditions ranging from 0 to 12 kg in increments of 4 kg. Results were compared with a double injection strategy for 12 kg loading conditions. It has been observed that for single injection 6% reduction in HC emission,67.5%,25% and 2% rise in NOx, CO and smoke opacity respectively, while for triple injection strategy, 25 % and 41.78% rise in HC and NOx emission and 8% and 15.78% reduction in CO and smoke opacity respectively . From the results it has been concluded that proper tuned multiple injections of the biofuelled RCCI operation have great potential to reduce the emission constituents without affecting the performance of the engine.

An experimental investigation on gasoline diesel and biofuelled RCCI combustion and its comparison with the conventional diesel combustion

Amongst all the low temperature combustion (LTC) strategies, reactivity controlled compression ignition (RCCI) is the most promising one due to their control on combustion pashing and heat release rate (HRR). This experimentation investigates the emission, performance and combustion characteristics of the modified constant speed non road single cylinder RCCI engine and its comparison with the conventional diesel engine. In RCCI operation, gasoline and blends of ethanol and gasoline, E10 and E20 were used as a low reactivity fuel (LRF), while diesel and blends of diesel and jatropha biodiesel, B10, B20 were used as a high reactivity fuel (HRF). The ratio of LRF and HRF maintained about 60:40. For RCCI operation, 10% hot exhaust gas recirculation (EGR), Injection pressure, 3 bar for PFI (port fuel injection) pressure, and 500 bar for HRF were used. Experimentation was carried out for 1500 rpm and 0, 4, 8 and 12 kg loading conditions. From experimental results, it has been concluded that, in comparison with the conventional diesel engine, for 12 kg loading condition, there was a 92% reduction in the NOx and 72% reduction in smoke opacity observed as an effect of reduction in combustion chamber temperature for E20-B20 blend. Compared to conventional diesel, there was an 11% rise in the brake thermal efficiency for the E10B10 fuel combination. As combined effects of NOx, Smoke opacity, and brake thermal efficiency are concerned, E10-B10 is the suitable combination for given operating conditions.

The effect of Zinc Oxide on Operation of Compression Ignition Engine with EGR fueled with Waste Cooking Oil Biodiesel

Nanoparticles are being used increasingly along with second and third generation biofuels. One major advantage of nanoparticles is its surface to volume ratio and also the number of active surfaces it possess which make it ideal for application as a catalyst in a chemical reaction or in biodiesel’s case an additive. Zinc Oxide (ZnO) has been employed in the current experimentation as an additive because it improves the properties such as the flash and fire point of the fuel in which it is blended in. Also, ZnO disperses well in fluid and provides advanced theoretical density along with not getting clogged in the fuel pump. In the present work Biodiesel derived from Waste cooking oil-Waste cooking oil methyl ester (WCOME) has been used along with ZnO nanoparticle and the amount of ZnO used is 80 ppm. The engine is also fitted with hot Exhaust Gas Recirculation system in order to decrease the Nitrogen Oxides (NOx) emission. Combustion properties such as Heat Release Rate and P-θ diagram have been thoroughly studied. The performance parameters like Brake Specific Fuel Consumption and Break Thermal Efficiency are also calculated and plotted on graphs for evaluation. Exhaust gases from the engine are measured and the results have been plotted on graphs for comparison. The properties of exhaust gases considered are % of Carbon Monoxide, Nitrogen oxides, Unburnt Hydrocarbons & Smoke Opacity. From the results it was revealed that all 3 parameters: Performance, Combustion & Emissions of the engine was improved by using ZnO as additive.

Effect of port injection of ethanol on engine performance, exhaust emissions and environmental factors in a dual-fuel diesel engine

This paper investigates the effect of ethanol addition and hot exhaust gas recirculation (EGR) on engine performance, exhaust emissions, and air-pollution damage-cost in a dual-fuel diesel engine. The ethanol is injected at low pressure into the intake manifold using a port-fuel injector while diesel fuel is injected directly into the cylinder. Only the duration of the ethanol injection is changed in the dual-fuel injection system while the diesel injection parameters are not changed. Ethanol fuel is added by port injection in such amounts as to provide additional heat energy in the range of 0–40% to the heat energy of the diesel fuel taken to the engine for any engine operating conditions. Moreover, 5%, 10%, and 15% rates exhaust gas recirculation (hot EGR) for each engine operating conditions are applied. The engine is operated at 1400, 1600, 1800 and 2000 rpm engine speeds at full load (≈40 Nm). In this paper, the highest improvement in engine performance and environmental factors is obtained with ethanol addition of 40% without the hot EGR at 1400 rpm. Under these conditions, the brake engine power ( BEP) and brake engine torque ( BET) increase of 6.9% and 8.1% while NOx emission and air-pollution damage-cost decreased of 32% and 23.9%, respectively. However, CO, HC, and smoke ( FSN number) emissions increased significantly. On the other hand, the brake thermal efficiency ( BTE) and brake specific energy consumption ( BSEC) are negatively affected by the ethanol addition and hot EGR.

Uji daya mesin diesel dengan hot EGR menggunakan bahan bakar campuran biosolar, metanol kadar rendah, dan jatropha

Motorized vehicles that are very suitable for transportation and heavy equipment vehicles are diesel engines, because their high combustion efficiency, reliability, fuel flexibility, and low fuel consumption make diesel widely used in several countries. The purpose of this study was to determine the effect of using a mixture of biosolar fuels, low levels of methanol and jatropha on power in a diesel engine using the hot Exhaust Gas Recirculation (EGR) system. This study uses an experimental method, using a 4JB1 diesel engine, the percentage of biodiesel fuel mixture, low levels of methanol and jatropha, Low Purity Methanol has a moisture content of 24.88%. The ratio of biosolar mixture, methanol and jatropha used are D85LPM5J10, D80LPM10J10, D75LPM15J10, D75LPM5J20, D70LPM10J20, D65LPM15J20, D65LPM5J30, D60LPM10J30 and D55LPM15J30. EGR openings vary from 0%, 25%, 50%, 75% and 100%. The test is carried out at a constant speed of 2000 rpm and is given a load of 25%, 50%, 75% and 100%. This study uses a dynamite brand Land &amp; Sea dynamite. The results of this study are the use of EGR resulted in increasing the value of brake power. The effect of the fuel mixture causes the value of brake power tends to fall compared to D100. When using D85LPM5J10, D80LPM10J10, D70LPM10J20 and D55LPM15J30 at low loads (25%) there is an increase in power by 12.03%, 7.50%, 5.01%, and 5.97%. Keywords: Power, Engine, Diesel, LPM, Jatropha, EGR.

Effect of biosolar fuels and S. Marginatum algae biofuel on equivalence ratio in diesel engine with EGR

One type of motor vehicle engine that is very suitable for transportation and heavy equipment vehicles is a diesel engine, because high combustion efficiency, reliability, fuel flexibility, and low fuel consumption make diesel widely used in several countries. A mixture of S. Marginatum algae biodiesel and bio solar fuel is used as an alternative fuel. This test is carried out by using variations in the percentage of the load, with variations of pure diesel fuel (D100) and a mixture of bio solar fuels, and algae biodiesel at t 1500 rpm. In this context, the purpose of this study was to obtain its performance curves from a diesel engine of the brand, using as fuel mixtures diesel oil, bio solar fuel, and S. Marginatum algae biodiesel, in the proportions B20, B20 + 10%, B20 + 15%, and B20 + 20%, the power take-off dynamometer test. The results showed that engine performance of equivalence ratio an increase with other models of the same used in the region, showing the best engine output in the region bio solar fuel mixtures with the Hot EGR (Exhaust Gas Recirculation) system.

EFEK METANOL KADAR RENDAH TERHADAP TORSI MESIN DIESEL DENGAN SISTEM HOT EGR

One type of motorized vehicle that is very suitable for transportation and heavy equipment vehicles is diesel engines, because of its high combustion efficiency, reliability, fuel flexibility, and low fuel consumption make diesel widely used in several countries. Lowgrade methanol mixtures and jatropha are used as alternative fuels. This study aims to study the effect of low purity methanol mixture and jatropha on torque in Isuzu 4JB1 diesel engine direct injection with Hot EGR (Exhaust Gas Recirculation) system using a mixture of biodiesel fuel, low grade methanol and jatropha. The low purity methanol used has a water content of 24.88% based on volume. The ratio of biodiesel, methanol and jatropha mixture used is D85LPM5J10, D80LPM10J10, D75LPM15J10, D75LPM5J20, D70LPM10J20, D65LPM15J20, D65LPM5J30, D60LPM10J30 and D55LPM15J30. EGR openings varied from 0%, 25%, 50%, 75% and 100%. Testing is carried out at a constant rotation of 2000 rpm and given a load of 25%, 50%, 75% and 100%. This study uses dynamite Land &amp; Sea dynamometer. The experimental results show that the EGR Effect can increase the torque value. Torque values tend to decrease when using a mixture of fuels compared to D100. At low loads (25%) there is an increase in the Torsi value for the fuel mixture D85LPM5J10, D80LPM10J10, D70LPM10J20 and D55LPM15J30 of 12.03%, 7.50%, 5.01%, and 5.97%.Keywords: Metanol, Torsi, Mesin, Diesel, EGR

Effects of Hot Exhaust Gas Recirculation (EGR) on the Emission and Performance of a Single-Cylinder Diesel Engine

With the increment in global demand for energy, there is a need to reduce vehicle emission, which is among the major causes of air pollution around the world. In order to reduce the emissions levels, this study focuses on the effects of hot exhaust gas recirculation (EGR) system on the performance and emissions of a direct injection (DI) diesel engine. The performance studied includes engine power, torque, brake mean effective pressure, fuel consumption and the exhaust emission. The engine used in this study was a single-cylinder, four-stroke engine with an air-cooled system at a rated speed of 3600 rpm with displacement of 0.219 litres. The engine was operated at varying speeds of 1600 to 3600 rpm with different percentages of EGR (5%, 7%, 10% and 15%). Based on the results, it was shown that EGR had decreased the engine brake power and torque while increasing fuel consumption at the same time. The engine with EGR has reduced the emission level of NOx from 800 to 240 ppm and CO2, from 9% to 4%, while increasing the CO from 2% to 4% and UHC from 10 to 100 ppm. Hence, it was concluded that low emission level of NOx and CO2 could be obtained using EGR as it can be used to improve the emission level of a homogeneous charge compression ignition (HCCI) even further in the extension of this study.

The effects of compression ratio and EGR on the performance and emission characteristics of diesel-biogas dual fuel engine

In this study, an experimental investigation on diesel-biogas dual fuel (DF) engine is presented based on energy and exergy analyses. The effects of change in compression ratio (CR), exhaust gas recirculation (EGR) and EGR temperature on the performance and emission characteristics of DF engine have been studied. In the first stage, engine was studied with increasing CRs of 16.5, 17.5, 18.5 and 19.5 in stepwise manner. It was found that the higher CRs were not only advantageous to the engine performance from first and second-law point of view but also to the exhaust emissions. In the second stage, DF engine was studied at the highest CR (19.5) and the effects of EGR were analysed. The engine was studied with EGR percentages of 5%, 10% and 15%, which caused slight improvements in engine efficiency at low load and simultaneous decrease in oxides of nitrogen (NOx) emissions. However, high EGR percentages at high loads showed slight decrease in engine efficiency. In the third stage, hot EGR was employed and the results obtained were compared with the cold EGR case. The results showed that the highest efficiencies both at low and high loads were obtained with hot EGR cases and at the same time exhaust emissions could also be kept in check.

Performance and emission characteristics of CIE using hydrogen, biodiesel, and massive EGR

Hydrogen is considered as an excellent energy carrier and can be used in diesel engines that operate in dual fuel mode. Many studies have shown that biodiesel, which is sustainable, clean, and safe, a good alternative to fossil fuel. However, tests have confirmed that using biodiesel or hydrogen as a fuel or added fuel in compression ignition engines increases NOx concentrations. Cooled or hot exhaust gas recirculation (EGR) effectively controls the NOx outflows of diesel engines. However, this technique is restricted by high particulate matter PM emissions and the low thermal efficiency of diesel engines.In this study, gaseous hydrogen was added to the intake manifold of a diesel engine that uses biodiesel fuel as pilot fuel. The investigation was conducted under heavy-EGR conditions. An EGR system was modified to achieve the highest possible control on the EGR ratio and temperature. Hot EGR was recirculated directly from the engine exhaust to the intake manifold. A heat exchanger was utilized to maintain the temperature of the cooled EGR at 25 °C.The supplied hydrogen increased NOx concentrations in the exhaust gas emissions and high EGR rates reduced the brake thermal efficiency. The reduction in NOx emissions depended on the added hydrogen and the EGR ratios when compared with pure diesel combustion. Adding hydrogen to significant amounts of recycled exhaust gas reduced the CO, PM, and unburned hydrocarbon (HC) emissions significantly. Results showed that using hydrogen and biodiesel increases engine noise, which is reduced by adding high levels of EGR.

Performance and NOx Investigation on Diesel Engine using Cold EGR Spiral Tube: A Review

The world has the same problem to reduce emissions. Based the problem, many technologies invented to reduce the Emission. One of them is EGR (Exhaust Gas Recirculation). EGR is the most simpleNOx reduction by circulating potion of exhaust gas return into the combustion chamber. EGR system is often known by the name the hot EGR where exhaust gas circulation process without cooling system. This new Hot EGR system is designed by the addition of cooling system with air-cooled type. So that the circulating of exhaust gas to be cooled in advance in such that the mass of air increases.This research aims to study the performance and a reduction in NOX of diesel engine with EGR using addition of air cooling system. The experiments were used on diesel engine Yanmar TF 85-MHDI

Multidimensional modeling of the effect of exhaust gas recirculation on exergy terms in a homogenous charge compression ignition engine fueled by diesel/biodiesel

Increased environmental pollution and finitude of fossil fuels have raised the concern for the main energy resources consumers in the world. Biodiesel fuel, as a renewable and degradable fuel, has received increasing attention globally. Although, the increased NOx emission owing to the inclusion of oxygen in the biodiesel fuel structure is a considerable environmental penalty. Use of hot exhaust gas recirculation (EGR) is recommended to reduce NOx emission. With respect to the fact that the hot EGR does not adversely affect the other emissions, exergy analysis can evaluate the performance of the engine supplied with biodiesel fuel using the hot EGR. In the current study, the effect of the hot EGR on a biodiesel-fueled homogeneous charge compression ignition(HCCI) engine in terms of the second law of thermodynamics is studied. The quantity of biodiesels equals 0%, 20%, and 50% of total injected pure diesel fuel mass (i.e., B0, B20, and B50) and the introduced EGR mass fraction equals 0%, 10%, 20%, and 30%. Based on a FORTRAN code, various accumulative exergy terms are calculated for different employed biodiesels and EGRs. The results revealed 66.7% increase in the accumulative heat loss exergy (AH.E), 2.9% decrease in the accumulative work exergy (AW.E), and 14.6% decrease in the accumulative irreversibility (AI), from B50-EGR = 0% to B50-EGR = 30%.Moreover, the exhaust thermomechanical exergy increased by 39.3% from B0-EGR = 0% to B0-EGR = 30%. Finally, the exhaust chemical exergy increased by 46.7% from B20-EGR = 0% to B20-EGR = 30%. It can be concluded from the results that the hot EGR could relatively decrease the work exergy. The irreversibility, on the other hand, significantly decreased while the heat transferred through the cylinder wall and exhaust increased.

An experimental investigation of performance and emission characteristics of diesel engine with blends of cottonseed oil methyl ester with cold and hot EGR

An experimental investigation of diesel engine using cottonseed oil biodiesel and its blends with exhaust gas recirculation (EGR) techniques has been carried out. An optimum nozzle opening pressure of 250 bar and lower static injection timing of 20° before top dead centre (bTDC) are considered because it has been observed that these conditions only give minimum emissions. From the test results, it could be noted that there is an increasing trend of emission characteristics of HC, smoke density and NOx for both cold and hot EGR for all blends of fuel with respect to brake power. As compared with cold EGR, the hot EGR gives lower emissions at all loads. In hot EGR, among the blends, at no-load and full-load conditions, the B100 gives the highest reduction in NOx of 14.23% and 7.91%, respectively. However, the use of EGR leads to a rise in soot emission because of soot–NOx trade-off for both the cases.

Emission reductions studies of a biodiesel engine using EGR and SCR for agriculture operations in developing countries

This paper reports the experimental results of a single cylinder diesel engine regarding performance, combustion and emission characteristics using Mahua (Madhucaindica) biodiesel and its blends in different volumetric proportions with petro-diesel. The thermo-physical properties of various blends selected for investigation have been experimentally measured for better evaluation of the performance characteristics. Tests have been carried out on a four stroke tangentially vertical (TV) single cylinder diesel engine at 1500rpm using an eddy current dynamometer. The static injection timing employed is 20° bTDC with constant nozzle opening pressure of 250bar. Selective Catalytic Reduction (SCR) as well as Cold and Hot Exhaust Gas Recirculation (CEGR and HEGR) techniques are employed to study the reduction of NOx. Results are compared at full load under steady state condition with conventional engine where no reduction techniques are applied. The comparison indicates that the SCR gives substantial reduction in oxides of nitrogen (NOx) as compared to other technique in a conventional diesel engine fuelled with biodiesel, B100. For B100 with SCR technique, the percentage reduction in NOx is around 20% as compared to conventional engine. This research has been carried out keeping in mind the energy consumption by pumps coupled to diesel engines for irrigation purpose and locomotive tractors used in developing countries. The research findings show that Mahua biodiesel gives equally good performance and lower emissions which make it a good alternative fuel to operate diesel locomotives as well as irrigation pumps without any engine modification.

Computational Analysis of Combustion of High and Low Cetane Fuels in a Compression Ignition Engine

Past research has shown that the combustion of low cetane fuels in compression ignition (CI) engines results in higher fuel conversion efficiencies. However, when high-cetane fuels such as diesel are substituted with low-cetane fuels such as gasoline, the engine operation tends to suffer from high carbon monoxide (CO) emissions at low loads and combustion noise at high loads. In this paper, we present a computational analysis of a light-duty CI engine operating on diesel, kerosene and gasoline. These three fuels cover a range of cetane numbers (CNs) from 46 for diesel to 25 for gasoline. Similar to experiments, the model predicted higher CO emissions at low load operation with gasoline. Predictions of in-cylinder details were utilized to understand differences in combustion characteristics of the three fuels. The in-cylinder mass contours and the evolution of model predicted in-cylinder mixture in Φ–T coordinates were then used to explain the emission trends. From the analysis, overmixing due to early single injection was identified as the reason for high CO emissions with low load gasoline low temperature combustion (LTC). Additional simulations were performed by introducing techniques like cetane enhancement, adding hot exhaust gas recirculation (EGR), and variation of the injection scheme. Their effects on low load gasoline LTC were studied. Finally, it is shown that use of a dual pulse injection scheme with hot EGR helped to reduce the CO emissions for low load gasoline LTC while maintaining low NOx emissions.