Optimizing Thermal Efficiency and Emissions in Hybrid HCCI-DI Combustion with Biodiesel-Diethyl Ether-Nanoparticle Blends

Objective: To determine the engine performance and emissions of a single cylinder Direct Injection (DI) diesel engine using diesel-biodiesel blends with nano additive. Method: Blends of diesel-biodiesel of different proportions are prepared, to which Nano additive Cerium Oxide (CeO2) is added. Properties like Flash point, Fire point, Calorific values are established for these blends. This fuel is used in single cylinder Direct Injection (DI) 4-strok diesel engine and performance of the engine is recorded along with emission details. Finding: In this present investigation cotton seed oil is taken as base oil (biodiesel) and Cerium Oxide (CeO2) as Nano additive. By using by using different blends of cotton seed oil methyl esters, for which Cerium Oxide (CeO2) Nano additives of size 30-50 nm is added in different proportions with neat diesel fuel. The experiments were conducted on a single cylinder Direct Injection (DI) 4-strok diesel engine, and observed the variation of Specific Fuel Consumption (SFC), Brake Thermal Efficiency, Air-Fuel ratio, Exhaust Gas Temperature (EGT), NOx emissions, Carbon Monoxide (CO), and Hydro Carbons (HC) emissions. Conclusion: The results have shown lower fuel consumption, better performance, and lower emissions of Carbon Monoxide (CO), Hydro Carbons (HC) but higher emissions of (NOx), in comparison to neat diesel fuel.

Predicting the performance and emissions of an HCCI-DI engine powered by waste cooking oil biodiesel with Al2O3 and FeCl3 nano additives and gasoline injection – A random forest machine learning approach

Reactivity controlled compression ignition (RCCI) engines have a high thermal efficiency as well as low emissions of soot and nitrogen oxides (NOx). However, there is a conflict between combustion stability and harmful emissions at high engine load. Therefore, this work presented a novel approach for regulating n-butanol/methyl oleate dual fuel RCCI at high engine load in attaining lower pollutant emissions while maintaining stable combustion and avoiding excessive in-cylinder pressure. The tests were conducted on a single cylinder engine under rated speed and 90% full load. In this study, n-butanol was selected as a low-reactivity fuel for port injection, and n-butanol/methyl oleate blended fuel was used for in-cylinder direct injection. Combustion and emission characteristics of the engine were first investigated with varied ratios of n-butanol port injection (PFI) and direct injection (DI). Results showed that as the ratio of n-butanol PFI and DI rose, the peak cylinder pressure and heat release rate increased, while NOx and soot emissions reduced, and carbon monoxide (CO) and hydrocarbon (HC) emissions increased under most test conditions. When RNBPI = 40% and RNBDI = 20%, the soot and NOx emissions of the engine were near the lowest values of all test conditions, yet the peak in-cylinder pressure and fuel consumption could not increase significantly. Therefore, the possibility of optimizing the combustion process and lowering emissions by adjusting the pilot injection strategy was investigated utilizing these fuel injection ratios. The results revealed that with an appropriate pilot injection ratio and interval, the peak in-cylinder pressure and NOx emission were definitely reduced, while soot, CO, and HC emissions did not significantly increase.

The combustion and emission characteristics of n-butanol/coal-derived naphtha blends in homogeneous charge compression ignition (HCCI) combustion mode were experimentally researched on a retrofitted diesel engine. The effects of intake temperature (T in ) and excess-air coefficient (λ) were mainly analyzed. The results show that the peak in-cylinder pressure (P max ) and peak heat release rate (HRR max ) of all tested fuels show an overall increasing trend as T in rises. The combustion gets faster and more stable, carbon monoxide (CO) and hydrocarbon (HC) emissions decrease, and the indicated thermal efficiency (ITE) first increases and then decreases. When T in remains constant, the P max and HRR max decrease and the combustion phase delays as the n-butanol volume fraction increases; CO and HC emissions gradually increase, except for that of lower T in , which shows a trend of first reduction and then increase. ITE gradually decreases in general, but when T in is higher than 100°C, coal-derived naphtha containing 24% of n-butanol in volume (B24N76) exhibits the highest ITE. In addition, for all tested fuels, both P max and HRR max decrease as λ increases and the combustion gets slower and less stable; CO and HC emissions deteriorate, and ITE gradually decreases. It is worth noting that B24N76 shows the best combustion stability for all λs and exhibits the lowest CO and HC emissions when λ are 3.0 and 3.5.

Experimental study of the performance and emission characteristics of diesel engine using direct and indirect injection systems and different fuels

ABSTRACTIn this experimental study, karanja biodiesel was prepared by two step transesterification process using potassium hydroxide as catalyst. This extracted biodiesel was used to determine performance, emission and combustion characteristics of different karanja oil diesel blends with 10% diethyl ether (DEE) at different loading conditions in an unmodified single cylinder, four-stroke compression ignition (CI) engine at 1500 rpm. Performance parameters evaluated are brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) while the emission of carbon dioxide (CO2), hydrocarbon (HC) and nitrogen oxides (NOX) were calculated at 20, 40, 60, 80% and full load conditions. Combustion characteristics evaluated were in-cylinder pressure and heat release rate at full load condition. The results of the investigation have been compared with that of diesel. BTE and BSFC of biodiesel blends were found to be greater than diesel. Reduction in NOX and CO2 was observed at full load condition while there was an increase in HC emission on intermittent basis. Peak in-cylinder pressure and heat release rate of B10DEE10 and B20DEE10 were found to be greater than that of diesel at full load condition.

An experimental investigation was conducted to study the effect of variable engine parameters like injection timing and compression ratio on performance and emission characteristics of single cylinder four stroke Ricardo E6/US diesel engine at a constant speed (1800rpm) running on diesel fuel biodiesel blends with nano additive. By transesterification process, the biodiesel was produced from waste cooking oil. The mixture percentage consisted of diesel fuel (B5, B10, B15, and B20) vol%, iron oxide nanoparticle (Fe2O3), particle size of 20 nm and different weight fractions (10ppm, 30ppm, 50ppm, 70ppm, and 100ppm) wt%. The injection timing was regulated for (20°, 30°, 38°, and 40°) bTDC, while compression ratio was (16:1, 17:1, 18:1 and 20:1). The design of experiments (DOE) approach of Taguchi method was employed to predict the optimum parameter settings for engine performance like biodiesel blend (B20), nano additive (100ppm), injection timing (38° bTDC), and compression ratio (17). The experimental results showed that the addition of nano additive to biofuel gives increased brake thermal efficiency (BTE) by 15.05% and reduced brake specific fuel consumption (BSFC) by 10.73%. Furthermore, the exhaust emissions like CO, HC, and smoke density reduced by 62.5%, 63.01%, 28.9%, respectively, but NOx, PM increased by 16.19%, 15.30%, respectively, compared to diesel fuel.

To determine the engine performance and emission parameters of diesel engine using diesel and bio diesel blends with nano additives. Blends of biodiesel of different proportions are prepared to which the zirconium oxide and titanium oxide nano additives are added. Here Wheat Germ Oil is taken as base oil with both the nano additives. The nano additives which are used here are of 30-50 nm and are added to biodiesel in different proportions. The following properties like density, viscosity, flash point, fire point, calorific value, pour and cloud point are been taken for this investigation. The experiments were conducted on a single cylinder direct injection (4) stroke diesel engine. The fuel is used in diesel engine the performance is noted along with the emission characteristics. The experiments have been conducted for Carbon Monoxide(CO), Hydro Carbons (HC), Carbon Dioxide (CO2), Oxygen (O2), NO, Specific Fuel Consumption (SFC), Brake Thermal Efficiency (BTE). The variations are seen in above characteristics. All these are compared with Pure Diesel.

An engine experimental platform with gasoline port injection and hydrogen/gasoline direct injection was built to study the effects of combined injection mode and ignition timing on combustion and emission characteristics of a spark-ignition engine. The study was performed in three modes, including gasoline port injection (GPI) mode, gasoline port injection plus gasoline direct injection (GPI + GDI) mode, and gasoline port injection plus hydrogen direct injection (GPI + HDI) mode, under the conditions of a constant excess air ratio and speed. Through the comparison and analysis of the three modes, the results reveal that combined injection is beneficial to increasing brake power and decreasing brake-specific fuel consumption and hydrocarbon (HC) and carbon monoxide (CO) emissions. The combustion process will be accelerated and concentrated with combined injection as well as hydrogen addition, and the effect of adding hydrogen is stronger than that of gasoline direct injection. Brake thermal efficiency and ...

This study presents a comprehensive analysis of the combustion chamber characteristics of a variable compression ratio compression ignition engine powered with microalgae biodiesel/diesel and their impact on engine performance and emissions. Both numerical and experimental methods have been employed to study the problem. A computational fluid dynamics method is used to study the axisymmetric flow in the cylindrical combustion chamber. Numerical simulations are obtained by solving time-independent steady, incompressible Navier-Stokes equation in a two-dimensional cylindrical coordinate system. Fluid flow characteristics, such as velocity vector field, streamlines, and pressure distribution are presented for different biodiesel blends. The velocity vector field analysis shows that biodiesel blends exhibit high velocities near the axisymmetric wall region. Swirl motion generated near the outer periphery of the combustion chamber influences the flow patterns. The experimental study involves the engine performance and its emissions. Due to the increase of biodiesel blend ratios in B20 (20% biodiesel and 80% diesel), B40 (40% biodiesel and 60% diesel), B50 (50% biodiesel and 50% diesel), and B100 (100% biodiesel), the brake thermal efficiency (BTE) decreases for a given brake power. B20, B100, and diesel exhibit 32.87%, 29.15%, and 34.45% BTE respectively. Higher brake-specific fuel consumption is obtained at no-load engine operations due to incomplete combustion of fuel. B20, B40, B50, and B100 show reductions of 16.04%, 20.85%, 25.66%, and 32.08% CO, respectively, as compared to diesel. HC emissions are very low for all biodiesel blends, while B20 exhibits a decrease of 7.35% HC compared to diesel. However, NOx emissions increase with the biodiesel blend ratio, with B100 exhibiting a 22.56% increase in NOx compared to diesel. Smoke emissions decrease with an increase in the biodiesel blend ratio, while B20 shows a 4.64% reduction. Results show that B20 offers a favorable balance between emissions reduction and engine performance. This study determines the biodiesel combustion characteristics and insights for the practical implementation of biodiesel blends in the transportation and energy sectors.

The current research article aims at improving LPG (Liquefied Petroleum Gas) utilization in a compression ignition engine powered with renewable fuel namely Calophyllum inophyllum biodiesel (CPBD). The combustion, performance and emission tests were conducted in the stationary single-cylinder water-cooled engine at a constant speed of 1500 rpm. The engine was remodeled to function in a dual fuel mode utilizing LPG as primary fuel and CPBD as pilot fuel. Through suction stroke, the primary fuel was supplied whereas the CPBD was injected through direct injection. The results show that the CPBD improved the performance of the engine under the LPG-based dual-fuel engine. There was an increase observed in Brake thermal efficiency (BTE) of CPBD upto 4.9% under LPG mode with 12% LPG energy share and a drop in BTE limited with LPG substitution. The water injection method was attempted in this research to increase the substitution of LPG, which resulted positively. The 5% water injection (5%W) increased the LPG substitution from 12% to 16% with a 7% improvement in BTE. There was a drastic improvement noted in hydrocarbon (HC) and Carbon Monoxide (CO) emission in dual fuel mode. The HC emission got decreased by 37.14% in CPBD+LPG mode to 45.7% in CPBD+LPG+5%W mode. Similarly, the CO emission got decreased by 65% with CPBD+LPG mode to 64% with CPBD+LPG+5%W mode. Likewise, the smoke emission also got decreased by 87% in CPBD+LPG mode to 74% in CPBD+LPG+5%W mode. However, NO emission got drastically increased by 90% and 85% in CPBD+LPG and CPBD+LPG+5%W respectively. To conclude, CPBD can be effectively used in CI engines under LPG-based dual fuel mode, which improves the performance and emission concurrently.

Experimental and theoretical analysis of the combustion process at low loads of a diesel natural gas dual-fuel engine

<div class="section abstract"><div class="htmlview paragraph">The rising demand for fossil fuels and the exploration of renewable energy sources from plants have gained significant attention due to their role in reducing emissions and enhancing energy security. Prosopis juliflora, abundantly available in India, offers a viable source for biodiesel production. This study investigates the performance and emission characteristics of a 5.2 kW, 1500 rpm, four-stroke single-cylinder compression ignition (CI) engine using blends of diesel, vegetable oil, and biodiesel derived from Prosopis juliflora seeds. The engine was tested with pure diesel, vegetable oil (PJO), biodiesel (B100), and biodiesel-diesel blends at 20%, 40%, 60%, and 80% by volume, designated as B20, B40, B60, and B80, respectively. Key performance metrics, including brake thermal efficiency (BTE) and brake specific energy consumption (BSEC), were measured, along with emissions such as carbon monoxide (CO), smoke, hydrocarbons (HC), and nitrogen oxides (NO). Results indicated that BTE for B20 was comparable to diesel, with values of 30.52% and 30.68%, respectively, at 5.2 kW. The BSEC for B20 was recorded at 11.79 MJ/kWh compared to 11.74 MJ/kWh for diesel. Emission analysis revealed that HC and smoke emissions were lower for all biodiesel blends compared to diesel. At 5.2 kW, HC emissions were 74 ppm for B20 versus 75 ppm for diesel, and smoke emissions were 67.7% for B20 compared to 69.1% for diesel. However, NO and CO emissions were slightly higher for biodiesel blends. This study suggests that Prosopis juliflora-derived biodiesel can effectively reduce HC and smoke emissions while maintaining performance, highlighting B20 as a promising alternative to conventional diesel fuel.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Reactivity Controlled Compression Ignition (RCCI) is a promising, high-efficiency, clean combustion mode for diesel engines. One of the significant limitations of RCCI is its higher unburned hydrocarbon (HC) and carbon monoxide (CO) emissions compared to conventional diesel combustion. After-treatment control of HC and CO emissions is difficult to achieve in RCCI because of lower exhaust gas temperatures associated with the low-temperature combustion (LTC) mode of operation<b>.</b> The present study involves combined experimental and computational fluid dynamic (CFD) investigations to develop the most effective HC and CO control strategy for RCCI. A production light-duty diesel engine is modified to run in RCCI mode by introducing electronic port fuel injection with the replacement of mechanical injectors by the CRDI system. Experimental data were obtained using diesel as HRF (High reactive fuel) and gasoline as LRF (low reactive fuel). The combustion simulation was performed using the CONVERGE 3D CFD tool. A reduced PRF mechanism was used where iso-octane represents gasoline and n-heptane as diesel. After validation of engine combustion, performance, and emission parameters, parametric investigations were carried out to investigate the effects of HRF's start of injection timing, premixed energy share, and intake charge temperature on combustion and exhaust emissions. The results obtained from both CFD and experiment show that the start of injection and intake charge temperature significantly influence combustion phasing, while the premixed ratio controls mixture reactivity and combustion quality. The blending ratio of high HRF to LRF governs reactivity stratification, which controls the magnitude of low and high-temperature heat release, combustion phasing and combustion duration. Controlling the amount of LRF and HRF in direct injection (DI) allows for shifting the heat release rate, which modifies combustion phasing and rate of pressure rise. Multiple injection strategies using double pulse helped reduce CO formation and achieve better control over combustion parameters with improved efficiency. By varying IVC temperature, optimizing SOI timing using a double injection strategy up to 18.57%, 25.5% reduction in CO and 93.68% drop in HC emissions, 3.7% reduction in soot are obtained in RCCI compared to the baseline case.</div></div>

The direct injection of natural gas (NG), which is an important research direction in the development of NG engines, has the potential to improve thermal efficiency and emissions. When NG engines operate in low-load conditions, combustion efficiency decreases and hydrocarbon (HC) emissions increase due to lean fuel mixtures and slow flame propagation speeds. The effect of two combustion modes (partially premixed compression ignition (PPCI) and high pressure direct injection (HPDI)) on combustion processes was investigated by CFD (Computational Fluid Dynamics), with a focus on different injection strategies. In the PPCI combustion mode, NG was injected early in the compression stroke and premixed with air, and then the pilot diesel was injected to cause ignition near the top dead center. This combustion mode produced a faster heat release rate, but the HC emissions were higher, and the combustion efficiency was lower. In the HPDI combustion mode, the diesel was injected first and ignited, and then the NG was injected into the flame. This combustion mode resulted in higher emissions of NOx and soot, with a diffusion combustion in the cylinder. HC emissions significantly decreased. Compared with PPCI combustion, HPDI had a higher thermal efficiency.