Common Rail Direct Injection Research Articles

Effects of injection timing and rail pressure on combustion characteristics and cyclic variations of a common rail DI engine fuelled with F-T diesel synthesized from coal

The use of Fischer-Tropsch (F-T) diesel synthesized from coal in automobiles can alleviate the shortage of petroleum and promote clean utilization of coal. In this study, the effects of injection timing (IT) and rail pressure (RP) on the brake thermal efficiency (BTE), combustion characteristics, and cyclic variations of F-T diesel were investigated on a turbocharged, 6-cylinder, common rail direct injection (CRDI) diesel engine. The results indicate that increasing RP results in higher BTE, whereas advancing IT results in an initial BTE increase and a subsequent BTE decrease. In comparison with petroleum diesel, the BTE of F-T diesel increased by 0.54% on average and by a maximum of 1% under different conditions. When the IT was advanced from 2 °CA to 18 °CA BTDC, the ignition delay periods (IDP) first decreased and then increased, whereas the combustion durations (CD) first lengthened and then shortened; peak cylinder pressure (PCP), peak pressure rise rate (PPRR), and peak combustion temperature (PCT) gradually increased; peak heat release rate (PHRR) first decreased and then increased at the low loads, whereas it always increased at medium and high loads. In comparison with petroleum diesel, the IDP of F-T diesel decreased by 22–31% at various conditions, and the CD was slightly longer than that of petroleum diesel at most conditions. Additionally, increasing RP resulted in a decrease in the IDP and CD, and a significant increase in PCP, PPRR, PHRR, and PCT. At low loads, the PPRR and PHRR of F-T diesel were 32.72% and 32.13% lower than that of diesel owing to the shorter ignition delay. This implies that using F-T diesel can help in attaining smoother engine running and has lower combustion noise. Advancing the injection timing or increasing the engine loads can decrease the cyclic variations, whereas increasing rail pressure results in the increment of COVpmax at low loads and the significant decrement of COVpmax at medium and high loads. In comparison with petroleum diesel, F-T diesel exhibits higher combustion stability owing to the better volatility and higher fuel reactivity.

Microscopic Spray Characteristics of Biodiesels Derived From Karanja, Jatropha, and Waste Cooking Oils

Abstract This study aims to assess the microscopic characteristics of Jatropha, Karanja, and Waste cooking oil-based biodiesels vis-a-vis conventional diesel under different ambient conditions in order to understand the in-cylinder processes, while using biodiesels produced from different feedstocks in the compression ignition engines. All test-fuels were injected in ambient atmosphere using a common-rail direct injection (CRDI) fuel injection system at a fuel injection pressure (FIP) of 40 MPa. Microscopic spray characteristics were measured using phase Doppler interferometer (PDI) in the axial direction of the spray at a distance of 60–90 mm downstream of the nozzle and at 0 to 3-mm distance from the central axis in the radial direction. All biodiesels exhibited relatively larger Sauter mean diameter (SMD) of the spray droplets and higher droplet velocities compared to baseline mineral diesel, possibly due to relatively higher fuel viscosity and surface tension of biodiesels. It was also observed that SMD of the spray droplets decreased with increasing distance in the radial and axial directions and the same trend was observed for all test-fuels.

Computational optimization of reactivity controlled compression ignition combustion to achieve high efficiency and clean combustion

One of the major limitations of reactivity controlled compression ignition is higher unburned hydrocarbon and carbon monoxide emissions and lower thermal efficiency at part load operating conditions. In the present study, a combined numerical approach using a commercial three-dimensional computational fluid dynamics code CONVERGE along with artificial neural network and genetic algorithm is presented to address the above limitation. A production light-duty diesel engine is modified to run in reactivity controlled compression ignition by replacing an existing mechanical fuel injection system with a flexible electronic port fuel injection and common rail direct injection systems. The injection schedules of port fuel injection and direct injection injectors are controlled using National Instruments port and direct injection driver modules. Upon validation of combustion and emission parameters, parametric investigations are carried out to establish the effects of direct-injected diesel fuel timing start of injection (SOI), premixed fuel ratio and intake charge temperature on the engine performance and emissions in reactivity controlled compression ignition. The results obtained show that the start of injection timing and intake charge temperature significantly influence combustion phasing, while the premixed fuel ratio controls mixture reactivity and combustion quality. By utilizing the data generated with the validated computational fluid dynamics models, the artificial neural network models are trained to predict the engine exhaust emissions and efficiency. The artificial neural network models for gross indicated efficiency and oxides of nitrogen (NOx) are then coupled with genetic algorithm to maximize gross indicated efficiency while keeping the NOx and soot emissions within Euro VI emission limits. By optimizing the start of injection timing, premixed fuel ratio and intake charge temperature simultaneously using the artificial neural network models coupled with genetic algorithm, 19% improvement in gross indicated efficiency, 60% and 64% reduction in hydrocarbon and carbon monoxide emissions, respectively, are obtained in reactivity controlled compression ignition compared to the baseline case.

Influence of high pressure fuel injection system on engine performance and combustion characteristics of Moringa Oleifera biodiesel and its blends

The present investigation studies the effect of advanced injection strategy on diesel engine characteristics fuelled with moringa oleifera biodiesel and its blends. Experiment was carried out on a Common Rail Direct Injection assisted diesel engine under different fuel injection pressure from 300 bar to 600 bar. Similarly, fuel injection timing was varied from 15°CA to 25°CA bTDC. The results showed that maximum brake thermal efficiency of 33.49% was obtained for B20 at higher injection pressure and advanced injection timing. Also, pure biodiesel achieved minimum carbon monoxide and maximum carbon dioxide emission of 0.01% vol. and 9.1% vol. respectively along with minimum unburnt hydrocarbon emission of 3 ppm. The B20 achieved maximum heat release rate of 41.7 kJ/m3°CA which is nearly equivalent to conventional diesel at advanced injection timing and higher injection pressure. But in view of nitric oxide emission, pure biodiesel showed an increasing trend at around 1389 ppm even after advancement of injection timing and injection pressure. Hence, this study revealed that advanced injection strategy along with Moringa Oleifera biodiesel at various percentages of blends reduces the exhaust emissions except oxides of nitrogen which thereby improves the efficacy of the engine. Even though the brake thermal efficiency was obtained maximum for the conventional diesel at standard operating condition, the same can also be achieved with biodiesel blends by increasing the injection pressure higher than that of the level used for conventional diesel.

Study of diesel fuel multiple injection characteristics using shadow-graphic imaging technique with CRDI system in constant volume chamber

The behaviour of injection spray characteristics is an essential part to better understand the combustion. Thus, to address the hurdles faced during physical measurement of spray structural properties an efficient visual technique is required. With the point of promoting the estimation of injected spray split-positional characterisation along with fuel injection time duration is being performed on multiple injection strategy with diesel as working fluid. Further, through visual examination characteristics of spray tip penetration along with the motion of the injected spray is performed. A visualisation set called shadowgraph optical technique is implemented to capture the injected fluid spray inside the combustion chamber by common rail direct injection. The developed MATLAB algorithm is validated from the obtained results, the effective estimation of spray intensity between 1st spray injection and 2nd spray injection supports in a way to choose the appropriate dwell time between successive injections which avoid the formation of the pocketed fuel-rich region. From the results of the case example, observed that 1st spray injection duration take persists throughout for 1680 µs, dwell time duration is 67.2 µs and 2nd spray injection duration occurs for 1276.8 µs. So, the choice of 2nd spray injection after 1680 µs from the injection point of 1st spray is advisable. Further, fuel spray tip penetration is observed as 50.6122 mm length and cone angle as 152°, examined and visualised during the operation. The developed MATLAB algorithm for an optical spray visualization technique has an efficient impact in determining the characteristics of fuel spray injected throughout the multiple injection process.

Gasoline-diesel dual fuel intelligent charge compression ignition (ICCI) combustion: Conceptual model and comparison with other advanced combustion modes

The internal combustion engines can remain the advantage over competitor technologies for automotive driven, especially the engine efficiency, exceeded 50% while maintaining ultra-low emissions. In this paper, a novel combustion mode characterized by dual high-pressure common-rail direct injection systems, denoted as intelligent charge compression ignition (ICCI) combustion, is proposed to realize high efficiency and clean combustion in wide engine operating ranges. Specifically, commercial gasoline and diesel, which are considered to be complementary in physical and chemical properties, are directly injected into the cylinder by the two independent injection systems, respectively. Through this unique design, the in-cylinder air-fuel mixtures can be flexibly adjusted by regulating injection timing and duration of different fuels, consequently obtaining suitable combustion phase and heat release rate. The ICCI mode can widely run from indicated mean effective pressure 2 bar to 16 bar with an utterly controllable cylinder pressure rising rate, around 50% indicated thermal efficiency and low NOx emissions. A series of experiments were carried out to compare the combustion and emissions of ICCI with other combustion modes (including conventional diesel combustion, reactivity-controlled compression ignition, partially premixed combustion, and gasoline compression ignition). The results show that at the medium engine loads, ICCI mode can reach much high indicated thermal efficiency, especially up to 52% along with extremely low NOx emissions. Prospectively, ICCI mode can realize real-time adjustments of in-cylinder mixture stratification and instantaneous combustion mode switch in one cycle at any operating conditions, and has an excellent commercial application prospect for energy conservation and environmental improvement.

Effects of Ethanol–Diesel on the Combustion and Emissions from a Diesel Engine at a Low Idle Speed

In this study, detailed experiments were conducted on the combustion and exhaust characteristics of ethanol–diesel blended fuels. The four-stroke four-cylinder common-rail direct injection diesel engine was used. The experiment was carried out at 750 rpm at a low speed idle, and a 40 Nm engine load was applied to simulate the operation of the accessories during the low idle operation of the actual vehicles. The test fuels were four types of ethanol-blended fuel. The ethanol blending ratios were 0% (DE_0) for pure diesel, and 3% (DE_3), 5% (DE_5) and 10% (DE_10) for 3%, 5% and 10% ethanol mixtures (by vol.%). Blending ethanol with diesel fuel increased the maximum combustion pressure by up to 4.1% compared with that of pure diesel fuel, and the maximum heat release rate increased by 13.5%. The brake specific fuel consumption (BSFC) increased, up to 5.9%, as the ethanol blending ratio increased, while the brake thermal efficiency (BTE) for diesel-ethanol blended fuels remained low, and was maintained at 23.8%. The coefficient of variation (COV) of the indicated mean effective pressure (IMEP) was consistently lower than 1% when ethanol was blended. The blending of ethanol increased the ignition delay from a 12.0 degree crank angle (°CA) at DE_0 to 13.7 °CA at DE_10, and the combustion duration was reduced from 21.5 °CA at DE_0 to 20.8 °CA at DE_10. When ethanol blending was applied, nitrogen oxides (NOx) reduced to 93.5% of the level of pure diesel fuel, the soot opacity decreased from 5.3% to 3% at DE_0, and carbon monoxide increased (CO) by 27.4% at DE_10 compared with DE_0. The presence of hydrocarbon (HC) decreased to 50% of the level of pure diesel fuel, but increased with a further increase in the ethanol blending ratio. The mean size of the soot particulates was reduced by 26.7%, from 33.9 nm for pure diesel fuel, DE_0, to 24.8 nm for DE_10.

Control of intake boundary conditions for enabling clean combustion in variable engine conditions under intelligent charge compression ignition (ICCI) mode

In a brand-new dual-fuel combustion mode called intelligent charge compression ignition (ICCI), the intake boundary conditions, including intake pressure, exhaust gas recirculation rate, and intake temperature, were modulated towards high-efficiency and clean combustion. A series of experiments were conducted in a modified single-cylinder engine. Commercial gasoline and diesel were respectively supplied to two decoupled common-rail direct injection systems. The experimental results show that intake pressure has a significant influence on ICCI combustion and emissions. The applicable intake pressure and gasoline ratio for ICCI steady operation under different engine loads are advised in this paper. At medium to high loads, exhaust gas recirculation is used to maintain stable combustion and delay combustion phasing. At 8 bar indicated mean effective pressure, slight exhaust gas recirculation (about 20% in this paper) could ease the combustion rate and adjust combustion phasing, optimizing heat release profiles. Gasoline double injection can further decrease hydrocarbon and carbon monoxide emissions but increase particulate matter emissions, maintaining nitrogen oxide emissions near EURO VI standard. At low engine load, the intake temperature is enhanced to make up low in-cylinder reactivity. The cooperation control of fuel supply ratio, diesel injection timing, and intake temperature is conducted to increase combustion efficiency and decrease nitrogen oxide and particulate matter emissions.

Gaseous emissions (regulated and unregulated) and particulate characteristics of a medium-duty CRDI transportation diesel engine fueled with diesel-alcohol blends

In this study, different diesel-alcohol (methanol, ethanol, and butanol) blends termed as ‘diesohols’ were used to investigate the performance and emission characteristics of a modern common rail direct injection (CRDI) transportation diesel engine. A comparative characterization of regulated emissions, unregulated emissions, and particulate matter (PM) to explore suitability of methanol, ethanol, and butanol blending with mineral diesel was the main objective of this study. In this study, engine experiments were performed at different engine loads (3, 6, 9 and 12 bar BMEP) and speeds (1500, 2500 and 3500 rpm). Results showed that the use of diesohols improved the engine performance, leading to relatively higher brake thermal efficiency (BTE) compared to baseline mineral diesel. Addition of alcohols in mineral diesel reduced both, the PM, and the oxides of nitrogen (NOx) emissions and this reduction was dominant at higher engine loads. Trace concentrations of various unregulated emission species such as isocyanic acid (HNCO), formaldehyde, etc. increased slightly with addition of alcohols in baseline mineral diesel. However, diesohol-fueled engine emitted relatively lower concentrations of sulfur dioxide (SO2), nitrogen oxide (NO), etc. compared to baseline mineral diesel. Amongst different primary alcohols, methanol showed most significant reduction in NOx and PM emissions and most significant increase in BTE compared to other alcohols. Overall, addition of alcohol, especially methanol and ethanol in mineral diesel showed significant potential for engine performance improvement and exhaust emission reduction in a medium-duty CRDI transportation diesel engine.

Comparative analysis on the effect of 1-decanol and di-n-butyl ether as additive with diesel/LDPE blends in compression ignition engine

ABSTRACT The present study utilizes (a) recycled low density polyethylene oil extracted through catalytic pyrolysis and (b) 1-decanol and di-n-butyl ether, as a blend component with diesel to power a single-cylinder, light-duty, water-cooled, four-stroke, common rail direct injection diesel engine. Experiments were conducted with two ternary blends and they were designated as (1) D70L20D10 (2) D70L20DNBE10. Later these results were compared with baseline diesel and D70L30 blend. Results indicated that replacing 10% by vol. of LDPE oil in D70L30 blend with 1-decanol and di-n-butyl ether was beneficial in increasing the combustion characteristics of the research engine, ignition delay period of oxygenated blends got shorter when compared to D70L30 blend. Slightly higher peak pressures were observed with the ternary blends than baseline fuels. Brake thermal efficiency of diesel was high at part load, whereas at peak load, D70L20DNBE10 shown 0.7% and 3.1% superior performance than diesel and D70L30 blend respectively. NOx emission for D70L20D10 and D70L20DNBE10 blend was found lower by 17.9% and 5.7% respectively than the D70L30 blend. Smoke opacity of the ternary blend was found to be lower against D70L30 and higher with diesel operations. The study revealed that 1-decanol and di-n-butyl ether could be a potential fuel additives for diesel engines operating with LDPE oil extracted from LDPE plastic waste.

An experimental-based artificial neural network performance study of common rail direct injection engine run on plastic pyrolysis oil

ABSTRACT Artificial neural network model was constructed to analyse and evaluate the engine performance. The experiments were conducted on a diesel engine with the blend of plastic pyrolysis oil with diesel and ethanol. Three input layer with two hidden layers and five output layers were used in artificial neural network modelling. The learning algorithm called feed-forward back-propagation was applied for the hidden layer. To train the neural network, 70% of the complete data from the experimentation was selected and 30% in predicting from the neural network. The model developed for prediction has excellent agreement as observed from the correlation coefficient (R) within the range of 0.964–0.9816. Statistical analysis shows that the ANN predicted and experimental results are in close agreement with each other. Overall, it could be concluded that it is a mean to predict the virtual sensing in studying the real time with established artificial neural network architecture. In addition, common rail direct injection engine operation could give complete freedom from diesel and thereby provides energy security and sustainable of a nation.

Effect of Nano-Graphene Oxide and n-Butanol Fuel Additives Blended with Diesel—Nigella sativa Biodiesel Fuel Emulsion on Diesel Engine Characteristics

The present investigation uses a blend of Nigella sativa biodiesel, diesel, n-butanol, and graphene oxide nanoparticles to enhance the performance, combustion and symmetric characteristics and to reduce the emissions from the diesel engine of a modified common rail direct injection (CRDI). A symmetric toroidal-type combustion chamber and a six-hole solenoid fuel injector were used in the current investigation. The research aimed to study the effect of two fuel additives, n-butanol and synthesized asymmetric graphene oxide nanoparticles, in improving the fuel properties of Nigella sativa biodiesel (NSME25). The concentration of n-butanol (10%) was kept constant, and asymmetric graphene oxide nano-additive and sodium dodecyl benzene sulphonate (SDBS) surfactant were added to n-butanol and NSME25 in the form of nanofluid in varying proportions. The nanofluids were prepared using a probe sonication process to prevent nanoparticles from agglomerating in the base fluid. The process was repeated for biodiesel, n-butanol and nanofluid, and four different stable and symmetric nanofuel mixtures were prepared by varying the graphene oxide (30, 60, 90 and 120 ppm). The nanofuel blend NSME25B10GO90 displayed an enhancement in the brake thermal efficiency (BTE) and a reduction in brake-specific fuel consumption (BSFC) at maximum load due to high catalytic activity and the enhanced microexplosion phenomenon developed by graphene oxide nanoparticles. The heat release rate (HRR), in-cylinder temperature increased, while exhaust gas temperature (EGT) decreased. Smoke, hydrocarbon (HC), carbon monoxide (CO2) and carbon monoxide (CO) emissions also fell, in a trade-off with marginally increased NOx, for all nanofuel blends, compared with Nigella sativa biodiesel. The results obtained indicates that 90 ppm of graphene oxide nanoparticles and 10% n-butanol in Nigella sativa biodiesel are comparable with diesel fuel.

Investigation on the effect of injection schedule and EGR in hydrogen energy share using common rail direct injection dual fuel engine

In this research work, four different diesel injection schedules have been experimented at a BMEP of 2 bar (Low load) in hydrogen diesel dual fuel (HDDF) mode, which are namely single pulse, double pulse phase-1, double pulse phase-2 and multi-pulse. The maximum possible hydrogen energy shares (HES) for single pulse, double pulse phase-1, double pulse phase-2 and multi-pulse injection schedules were 73.99%, 48.98%, 34.46% and 24.39% respectively. Over the injection schedules, double pulse phase-2 improved the brake thermal efficiency (BTE) from 19.50% (single pulse) to 21.61% with a penalty in NO emission. On the other hand, multi-pulse moderately increased the BTE with significant reduction in NO beside rise in smoke emission. At a BMEP of 5 bar (Medium load) operation, there was a considerable reduction in NO emission at maximum range of HES level with 18.21% of EGR, moreover the engine stability was improved with minor increase in smoke emission.

Optimization of operating parameters of an off-road automotive diesel engine running at highway drive conditions using Response Surface Methodology

Abstract The typical tradeoff between the two major emissions from compression ignition (CI) engines, smoke and oxides of nitrogen, is the unresolved challenge to the researchers. Techniques like engine downsizing, lowering intake oxygen concentration, multiple injections, use of retarded injection timings and higher injection pressures, etc. are widely employed for the alleviation of these harmful emissions. The influence of variation of fuel injection pressure (FIP), boost pressure, pilot injection timing (PIT), pilot injection quantity (PIQ) and main injection timing (MIT) are experimentally investigated in the present work. Mahindra mHawk four-cylinder diesel engine with provisions of a variable-geometry turbocharger (VGT), exhaust gas recirculation (EGR), and common-rail direct injection (CRDi) is chosen for the experimentation. Test runs are conducted at 1750 rpm and 80.3 N.m (4.6 bar bmep) corresponding to highway drive conditions, using 10 % EGR. Response surface methodology is employed for the design of experiments and to analyze the experimental data. Multi-objective response optimization is carried out to optimize engine-operating parameters that give desired performance and engine-out emissions. Confirmatory tests are conducted at design conditions to validate the results predicted by the model. This study reveals that the optimum performance and emission characteristics could be obtained using 120 kPa boost pressure; 61.1 MPa fuel injection pressure; 11.5 % pilot injection quantity with pilot injection at 332 °CA and main injection at 359 °CA.

The effect of hydrogen addition to Cynara biodiesel on engine performance and emissions in diesel engine

ABSTRACT This paper aims at studying, the effects of biodiesel-diesel, biodiesel-hydrogen, and diesel-hydrogen fuel blends on engine performance, emissions, and combustion characteristics were investigated in a modified 4-cylinder, turbocharged, common rail direct injection, and compression ignition (CI) engine. Biodiesel was produced from through transesterification of Cynara cardunculus seed oil according to EN 14214 standards with a short-chain alcohol in the presence of a catalyst. The addition of hydrogen as a combustion enhancer used to counteract the increase in emissions and further improve engine performance. Hydrogen was injected in small quantities in the air intake manifold, while diesel-biodiesel blends were injected directly inside the cylinder. Diesel (D), biodiesel (B100), and biodiesel-diesel-hydrogen (B7+H2.5), biodiesel-hydrogen (B100+H2.5), and diesel-hydrogen (D+H2.5) fuel blends were used. Experimental results showed that while maximum engine power and maximum engine torque were obtained with B7+H2.5, the highest thermal efficiency was achieved with B100+H2.5. The lowest specific fuel consumption was obtained as 217 g/kWh at 2000 rpm with diesel. Maximum cylinder pressure and heat release rates were measured as 100.48 bar and 576.12 kJ/m3 deg with diesel fuel at 3000 rpm. The minimum CO emissions were obtained as 0.04% with B100 and B100+H2.5 fuels. CO2 and HC emissions reduced significantly whereas NOx increased, compared to diesel fuel.

Combined effect of oxygenated additives, injection timing and EGR on combustion, performance and emission characteristics of a CRDi diesel engine powered by sapota biodiesel/diesel blends

Biofuels from renewable sources deem itself as a sustainable option for a diesel engine as fuel. In the present study, biodiesel extracted from seeds of sapota through the transesterification method was used along with diesel in one single cylinder, common rail direct injection (CRDi) diesel engine. Also, this research attempt to study the influence of oxygenated additives, injection timing (IT) and exhaust gas recirculation (EGR) on different engine characteristics fueled with diesel/biodiesel blends. For this purpose, oxygenates viz., n-butanol (n-B) and dimethyl carbonate (DMC) were used as an additive to B40% blend (60% vol. diesel + 40% volume biodiesel). Two test fuels (blends) were prepared by adding 10% by volume of n-butanol and DMC to B40% blend separately. Experimentation was operated at three different injection timings like (21°CA, 23°CA and 25°CA bTDC) and EGR rates (5%, 10%, and 15%) at the engine rated power output. Results reveal that the peak in-cylinder pressures and heat release rate (HRR) let fall slowly as the injection timing was late from 25°CA bTDC to 21°CA bTDC at all the EGR rates. When related to diesel, the combustion incident happened nearer to the top dead center (TDC) when advanced injection timing from 21°CA to 25°CA bTDC. Both oxygenated blends exhibit similar brake thermal efficiency (BTE) among them and a 4.7% decrease in performance was noted against diesel operation. Oxygenated additive to B40% blend elevated the oxides of nitrogen (NOx) emission. Nearly 7% and 60% of reduction in NOx emission were achieved when fuel with an n-butanol blend when related to DMC blend and diesel. About 14%, 10% and 8% lesser smoke opacity than diesel, B40%, and n-butanol blends were achieved with DMC blend injected at 25°CA bTDC and 5% EGR rate. In summary, n-butanol and dimethyl carbonate can be recommended as oxygenated additives when fueled with diesel/biodiesel blend at advanced injection timing and low EGR rates.

Impact of 1-Hexanol/diesel blends on combustion, performance and emission characteristics of CRDI CI mini truck engine under the influence of EGR

Biofuels are the most promising sustainable and renewable alternative to diesel fuel. In the present renewable energy world, alcohols are gaining prime importance due to their nature of production and fuel properties. The present work aims to investigate the impact of 1-Hexanol and exhaust gas recirculation (10% and 20%) on engine characteristics of the common rail direct injection compression ignition engine. The experiment is carried out on a bench engine. The fraction of 1-Hexanol is varied from 10% to 40% in a step of 10% by volume. The results demonstrate that the use of 1-Hexanol/diesel blends lowers the cylinder pressure and mean gas temperature, which is 4.25% and 1.88% lower at 60% load for 40% 1-Hexanol compared to neat diesel fuel operation. The combustion duration is increased by 2.66˚CA for 40% 1-Hexanol at 60% load compared to neat diesel fuel. However, an improvement in net heat release rate is noted which is 13.95% higher at 60% load for 40% 1-Hexanol, this increment is due to prolonged ignition delay. With the use of 1-Hexanol in the engine, there is a drastic reduction in nitrogen oxide emission is observed, this is the greatest impact of 1-Hexanol. However, a slight increment in the hydrocarbon and carbon monoxide emission is also noted due to poor fuel properties like lower cetane number, higher viscosity and higher latent heat of evaporation of 1-Hexanol. Compared to all other blends in the test 10% 1-Hexanol shows comparable results with pure diesel fuel, which is only 2.37% lower in brake thermal efficiency, 3.6% higher in brake specific fuel consumption, 17.55% lower in nitrogen oxide emission, 18.18% higher in hydrocarbon and 33.33% higher in carbon monoxide emission is noted. The exhaust gas recirculation helps in reducing the NOx emission, 40% 1-Hexanol is less sensitive to exhaust gas recirculation. Up to 40% of 1-Hexanol can be used in the CI engine without any modification. It is concluded that 1-Hexanol is a sustainable renewable biofuel due to the reason that even though the use of 1-Hexanol lowers the performance which helps in reducing the NOx emission greatly; the performance can be improved by modifying the engine parameters.

Effect of hydrogen fuel at higher flow rate under dual fuel mode in CRDI diesel engine

The prime intention of this work is to provide a maximum replacement for diesel using hydrogen in a common rail direct injection equipped diesel engine. The experiment was conducted upto 5.2 kW brake power constant speed water-cooled engine. In the combustion chamber, diesel fuel was injected at a crank angle of 23⁰ bTDC, making it an ignitor for the premixed mixture of hydrogen and air. Hydrogen is injected at 6 different proportions ranging from 6 to 36 liter per min (LPM). The air and hydrogen gas were mixed homogeneously using the timed manifold injection technique, which was controlled through the in-house PC based data acquisition (DAQ) program developed on data factory. The electronic control unit helps to induct the hydrogen for a period of 211⁰ CA during the suction stroke. Performance, emission and combustion studies were made with the different levels of hydrogen injection, which proves that the 30 LPM of hydrogen provide the best results. Further, 30.65% improvement was achieved in brake thermal efficiency with 23.48% decreased brake specific energy consumption. This also helped to reduce the harmful emissions like CO, CO2, UHC and smoke by 22.3%, 14%, 32.74% and 43.86%, respectively. However, oxides of nitrogen emission level was increased by 7.3% compared to that of the diesel fuel at its maximum power output setting. The duration of the combustion also reduced due to the higher flame speed character of hydrogen. Thus, the overall results conclude that the addition of hydrogen improved the performance factors and reduced all the emission values of the common rail direct injection diesel engine at an optimum level of 30 LPM.

Effect of alcohols on combustion characteristics and particle size distribution of a diesel engine fueled with diesel‐castor oil blended fuel

AbstractThe research was motivated to experimentally study the effect of alcohol addition on the performance, combustion characteristics, particle size distribution (PSD) and exhaust emissions of a common rail direct injection (CRDI) diesel engine fueled with diesel‐castor oil blended fuels. The main properties of the blended fuels were measured by the standard test procedures. The results revealed that, compared with diesel fuel, the brake specific fuel consumption (BSFC) was increased by an average of 7.7%, 8.5% and 16.5% for DA80B10E10, DC80B20, and DC60B20E20 fuels respectively. The brake thermal efficiency (BTE) kept almost identical for the blended fuels. The peak in‐cylinder pressure was about 0.4 MPa higher and the heat release rate (HRR) was evidently higher than that of diesel fuel, and the combustion duration was 5–12 crank angles shorter. The blended fuels exhibited bi‐modal PSD, and diesel fuel showed uni‐modal behavior under all operating conditions. The total number concentration (TNC) of particles was larger, but the geometric mean diameter (GMD) was lower than that of diesel fuel. Nitrogen oxide (NOx) emissions were increased by about 30% and hydrocarbon (HC) was evidently higher for the blended fuels under almost all operating conditions, but carbon monoxide (CO) emissions were about 22% lower than that of diesel fuel.

Influence of hydrogen enriched producer gas (HPG) on the combustion characteristics of a CRDI diesel engine operated on dual-fuel mode using renewable and sustainable fuels

In the present experimental investigation, an effort has been made to enhance the performance of a producer gas fueled diesel engine. In this present work, producer gas was being mixed with hydrogen with a flow rate of 8 lpm. To harness maximum performance, CRDI diesel engine was operated at four injection timings in the range from 0 (TDC) to 15 deg., before top dead center (bTDC) and varied in steps of 5. Similarly, injection pressures were varied in the range of 600 to 1000 bar in steps of 200. In the first phase of the work, influence of common rail direct injection system (CRDIS) on the performance and emission characteristics of a single cylinder four stroke water cooled compression ignition (CI) engine operated on dual-fuel mode using neem oil methyl ester (NeOME) and hydrogen enriched producer gas (HPG) have been investigated. Results obtained were compared to the engine operation with conventional mechanical fuel injection system (CMFIS). Subsequently in the next phase of the work; influence of combustion chamber for optimum performance was investigated. In order to match proper combustion chamber for optimum fuel injection timing (FIT) and fuel injection pressure (FIP), two types of combustion chambers such as hemispherical (HCC) and re-entrant configurations (RCC) were used. Results of investigation on NeOME-HPG operation with RCC and optimized conditions showed 3.02% increased brake thermal efficiency with 22.4% reduced smoke, 12.2% reduced HC, 10.8% reduced CO, and 18.6% increased NOx levels compared to the same fuel combination with HCC. Further, increased cylinder pressure and HRR were observed with RCC. Investigation with NeOME-enriched PGwith hydrogen based dualfuel operation showed satisfactory engine operation.