Six-cylinder Engine Research Articles

The impact of fuel and injection strategy on combustion characteristics, emissions and efficiency in gasoline compression ignition operation

Gasoline compression ignition in diesel engines has been proposed in order to meet increasingly stringent emission regulations without sacrificing efficiency. In this study, a six-cylinder heavy-duty diesel engine was operated in a mixing controlled gasoline compression ignition mode to investigate the influence of fuels and injection strategies on the combustion characteristics, emissions, and thermal efficiencies. Fuels, including ethanol (E), isobutanol (IB), and diisobutylene (DIB), were blended with a gasoline fuel to form E10, E30, IB30, and DIB30 based on volumetric fraction. These four blends along with gasoline formed the five test fuels. With these fuels, three injections strategies were investigated, including late pilot injection, early pilot injection, and port fuel injection/direct injection. The impact of moderate exhaust gas recirculation on nitrogen oxides and soot emissions was examined to determine the most promising fuel/injection strategy for emissions reduction. In addition, first and second law analyses were performed to provide insights into the efficiency, loss, and exergy destruction of the various gasoline fuel blends at low and medium load conditions. Overall, the emission output, thermal efficiency, and combustion performances of the five fuels were found to be similar and their differences are modest under most test conditions. E30 with the port/direct fuel injection strategy obtained the peak brake thermal efficiency (46.9%) and gross indicated thermal efficiency (52.2%) at 14 bar. At 7 bar, the peak brake thermal efficiency (44.2%) and gross indicated thermal efficiency (52.5%) also belonged to E30 with the late pilot injection strategy. The second law analysis revealed that exergy destruction was mostly influenced by the fuel type and not by the injection strategy for the 14 bar operating conditions. However, the opposite trend was observed for the 7 bar case. In addition, port fuel injection in combination with oxygenated fuel blends was found to be helpful to suppress soot emissions for operation with exhaust gas recirculation.

Experimental study on combustion and unregulated emission characteristics of a diesel engine fueled with light hydrocarbon/diesel blends

Rigorous emission regulations are provoking to pursue substitute of diesel with clean and sustainable alternative fuels to work out the problem of the regulated and unregulated emissions and diesel depletion. In this paper, the partial load characteristics of emission especially unregulated and combustion characteristics of a six-cylinder compression ignition diesel engine fueled with conventional diesel and 85% light hydrocarbon (LHC)-diesel blends were investigated and compared at the load points of 50%, 75% and 100% and the speed of 1000 rpm. Gas chromatography-mass spectrometry (GC–MS) technology was utilized to identify components of both tested fuel and unregulated emissions. The cylinder pressure, pressure rise rate, indicated power, heat release rate and emissions were comparatively analyzed between these two fuels. The gaseous pollutants including NOx, CO and total hydrocarbon (THC) are determined by gas analyzer. Based on the experimental results, blending LHC extend the ignition delay period, thus leading to its combustion phase lag behind that of diesel fuel by 3°CA. Significant reduction in specific NOx and CO emissions was noted while THC emission is higher in engine fueling LHC/diesel blends. The dominant unregulated pollutants primarily include organosilicon compounds (OSC), aromatic compounds (AC), and non-aromatic hydrocarbons and their derivatives (NAHC). The determinant factors on OSC emissions are summarized into the content of antifoaming agents in lubricants and the load conditions. The AC emissions of both fuels have an ascending tendency with the increase of load and the AC emissions of LHC/diesel blends are obviously less than that of pure diesel. The NAHC emissions usually appear under higher load conditions with regard to LHC blends and the content is far lower than that of diesel. In a word, blending diesel with LHC significantly contributes to improve both combustion and emission characteristics.

Effect of double-layer hole nozzle with narrow spray angle on combustion and emissions in dual-fuel natural gas engine

Diesel injection plays a significant role in the mixing process of dual-fuel engine. The diesel nozzle is an important interaction between the injection system and the combustion chamber that deserves more investigation. To fully assess the effect of a diesel nozzle on combustion and emissions in a dual-fuel engine, and to avoid the diesel impingement on the wall and lubricant dilution with early injection strategy, a diesel nozzle with double-layer hole and a narrow spray angle was designed to enhance the air utilization of the central part of the pre-mixture natural gas, matching combustion with an open chamber shape. Comparison of the high dispersion nozzle with a narrow spray angle and a traditional nozzle on combustion was performed in a six-cylinder dual-fuel engine with a low compression ratio. The results showed that the narrow spray angle nozzle is beneficial at low load with earlier pilot injection, but the original nozzle achieves higher thermal efficiency than that of the narrow spray angle nozzle with the same injection strategy in high load conditions. The main cause remains that the narrow spray angle nozzle has a relatively small hole diameter and short spray penetration due to higher charge density at high load. The flame propagation ignited a natural gas mixture near the cylinder wall, resulting in a slower combustion process and a smoother heat release curve. With a relatively moderate combustion process and considerably earlier injection timing, a narrow spray angle nozzle will reduce rough combustion concerns at high load.

Improving the energy efficiency of a 6ChN13/15 gas engine with a Miller cycle by optimizing the valve timing

Introduction (problem statement and relevance). The object of research in this work is an inline six-cylinder gas engine 6ChN13/15 with a Miller thermodynamic cycle. On the basis of its computer model studies minimization of the specific effective fuel consumption has been reached due to variation study of gas distribution and air supply systems parameters.The purpose of the study was to investigate the parameters regulation effect of gas distribution and air supply systems on the performance of a 6ChN13/15 gas engine with a Miller cycle on the external speed characteristic basing on numerical modeling.Methodology and research methods. The research was carried out by the method of computer simulation. Numerical modeling was made on the basis of data obtained during a full-scale experiment of a 6ChN13/15 gas engine with Miller thermodynamic cycle.Scientific novelty and results. A comparative analysis of a gas engine optimization results has been carried out. The results obtained will be used to create a gas engine and its further optimization by controlling the working process and the air supply system.Practical significance. The results obtained may be of interest to truck car manufacturers and engine specialists.

Heavy Duty Natural Gas Single Cylinder Research Engine Installation, Commissioning, and Baseline Testing

Natural Gas (NG) Internal Combustion Engines (ICE) are a promising alternative to diesel engines for on-road heavy-duty applications to reduce greenhouse gas and harmful pollutant emissions. NG engines have not been widely adopted due to the lower thermal efficiency compared with diesel engine counterparts. To develop the base knowledge required to reach the desired efficiency, a Single Cylinder Engine (SCE) is the most effective platform to acquire reliable and repeatable data. A SCE test cell was developed using a Cummins 15-liter six-cylinder heavy-duty engine block modified to fire one cylinder (2.5-liter displacement). A Woodward Large Engine Control Module (LECM) is integrated to permit implementation of real-time advanced combustion control. Intake and exhaust characteristics, fuel composition, and exhaust gas recirculated substitution rate (EGR) are fully adjustable. A high-speed data acquisition system acquires in-cylinder, intake, and exhaust pressure for combustion analysis. The baseline testing shows reliable and consistent results for engine thermal efficiency, indicated mean effective pressure (IMEP), and coefficient of variance of the IMEP over a wide range of operating conditions while achieving effective control of all engine control and operation variables. This test cell will be used to conduct a research program to develop new and innovative control algorithms and CFD optimized combustion chamber designs, allowing ultra-high efficiency and low emissions for NG ICE heavy-duty on-road applications.

An approach for waste heat recovery of internal combustion engine: In-cylinder steam-air expansion

• An approach based on CSAE cycle was proposed for IC engine WHR. • Steam temperature has a greater effect on WHR potential compared with steam amount. • The NA mode is recommended for the steam expansion cylinder. • Engine brake efficiency can be increased by 7.0 percent points at most by CSAE cycle. • The proposed WHR approach has little effect on the engine BMEP. To recover waste heat and increase the fuel efficiency of internal combustion engines, an approach based on in-cylinder steam–air expansion is proposed, which has simpler design but higher practicality than previous methods. In the multi-cylinder engine, a cylinder is specially used for steam expansion (called steam expansion cylinder) without fuel entry and firing. The high-temperature steam generated by engine waste heat is injected into the steam expansion cylinder, in which it expands together with air and outputs effective work. The energy-saving potential and influencing factors of this approach were investigated on a six-cylinder natural gas engine through the simulation and some interesting findings were obtained. At the same engine operating conditions, the steam temperature has greater effects on waste heat recovery potential than steam amount. The cycle work of the steam expansion cylinder is improved largely by introducing air. However, if further increase intake pressure (e.g., greater than 0.4 bar), the improvement of cycle work in the steam expansion cylinder is not obvious, thus the naturally aspirated mode is recommended. When this approach is applied, the maximum brake mean effective pressure is approximately equal to the level of the original engine at 1600 rpm and 2000 rpm but slightly lower at 1200 rpm. Nevertheless, the brake efficiency of the engine has an obvious rise at all three speeds, which could increase by up to 5.7, 7.0 and 6.8 percentage points at 1200 rpm, 1600 rpm and 2000 rpm, respectively. Therefore, the proposed approach can effectively recover engine waste heat with little effect on power performance.

Upgrading the performance of a six-cylinder CNG Engine with the induction of Turbocharger for HCV application

The world is having catastrophe of environmental pollution and fossil fuel depletion. Adaptation of alternative fuels is a healthy solution in reducing exhaust emissions in the automobile sector. Compressed Natural Gas (CNG) as a fleet fuel has played a vital role in the HCV sector. Many developmental and optimization work has been taken place for the CNG engines in the recent times. Due to the recent upsurge in diesel prices, the HCV sector is moving towards the CNG fuel vehicle. The HCV sector requires a heavy performance engine for its day-to-day application. In this research paper a baseline six-cylinder, naturally aspirated CNG engine used for bus application is selected to upgrade its power and torque performance. Based on the baseline CNG engine data, an appropriate turbocharger for the engine is selected with the help of M/s Garrett turbocharger manual. A 2-D simulation of the turbine is also carried out to understand the pressure and temperature distribution profile inside the turbine. The experimental results showing the increase in power, torque, volumetric efficiency, BMEP and thermal efficiency is illustrated in the research work below.

Modeling the emissions of a gasoline engine during high-transient operation using machine learning approaches

To perform a suitable optimization method in terms of emission and efficiency for an internal combustion engine, first highly accurate and possible real-time capable modeling for the transient operations should be provided. In this work, the modeling of NO x and HC raw emission (before exhaust aftertreatment systems) in a six-cylinder gasoline engine under highly transient operation was performed using machine learning approaches. Three different machine learning methods, namely Artificial Neural Network, Long Short-Term Memory, and Random Forest were used and the results of these models were compared with each other. In general, the results show a significant improvement in accuracy compared to other studies that have modeled transient operations. Furthermore, the shortcoming of Artificial Neural Network for the prediction of the HC emission by the transient operation is observed. The coefficient of determination ( R2) for the best model for NO x prediction is 0.98 and 0.97 for the training data and test data, respectively. This value is 0.9 and 0.89 for the best HC prediction model.

Improving frictional performance of ring-liner system under cylinder deactivation conditions by surface texturing

In this study, a method of surface texture is considered to improve the frictional performance of the ring-liner system (i.e. RLS) under the conditions of cylinder deactivation (i.e. CDA). To assess the effectiveness of the method, a lubrication model is developed with considerations of the liner deformation, the actual rheological properties of lubricant, and the lubricant transport. By solving the model numerically, the friction reduction effect of surface texture for the RLS under the CDA is investigated. The results show that the surface texture can improve the friction properties significantly. For a six-cylinder gasoline engine, 7.57% and 7.28% decreases in the total average friction loss and power loss are observed when the RLS under the CDA is surface textured.

Control methods for variations in natural gas composition in air–fuel controlled natural gas engines

In the present study, the countermeasures are proposed to minimize the problem on torque and power output performance and exhaust gas emissions of natural gas engine with use of lower calorific gas. An experiment was conducted to identify thermal efficiency and harmful exhaust gas emission characteristics under partial load conditions in order to improve efficient fuel use in engines affected by the introduction of low calorific gases. A countermeasure for coping with emission gas regulations and preventing thermal efficiency deterioration under rated power operating conditions was then presented. An 11 L six-cylinder turbo-charged engine for city buses compliant with the EURO 6 regulation was used in the experiment, and the results obtained using the reference natural gas fuel were compared with those obtained using simulated low calorific gases. Pure methane (CH 4) was also used to investigate the effects of gas composition changes on thermal efficiency and exhaust gas emissions.When N2 is added or pure CH 4 is used under partial load operating conditions, the combustion rate decreases; consequently, the optimum ignition timing is additionally advanced relative to that obtained when the reference natural gas fuel is used. If the N2 mixing ratio is increased to a minimum of 4.7% under rated power operating conditions, combustion becomes unstable. Stable operation can be secured by increasing the set base fuel amount, 2.35% and 9.41% for pure CH 4 and 8% N2, respectively; however, torque decreases in proportion to the combustion speed of the gas fuel. The strategy of boost pressure control for the torque compensation can minimize the decrease in thermal efficiency.

Misfire detection of diesel engine based on convolutional neural networks

With the ever-stringent vehicles exhaust emission standard and higher requirements on on-board diagnostic technology, the importance of misfire detection in vehicle emission control is emerging. The performance of a traditional misfire detection algorithm predominantly depends on the features and classifier selected. Fixed and handcrafted features require either a reliable dynamic model of an engine or a large number of experiment data to define the threshold, and then, form a map. Since convolutional neural networks (CNNs) have an inherent adaptive design and integrate the feature extraction with classification functions into a compact learning framework, the misfire fault-sensitive features can be auto-discovered from raw speed signals. Furthermore, CNNs can detect the fault features of the misfire through network training with fewer engine operating conditions. In this paper, the theory and method of the misfire diagnosis based on CNNs are presented. The experimental data for network training and testing are sampled on a six-cylinder inline diesel engine. The misfire patterns containing every one-cylinder and two-cylinder misfire are tested under the wide speed and load conditions of the engine. The results show that when the engine operates under steady-state conditions, one-cylinder or two-cylinder complete misfires can be detected accurately by CNNs. In addition, one-cylinder partial misfire is employed to examine the adaptability of trained 1-D CNN. It turns out that when the partial misfire reaches the same level as half amount of the normal fuel injection quantity, one-cylinder partial misfire can be detected with accuracy more than 96%. At last, the misfire detection under the non-stationary conditions, such as acceleration or deceleration, is conducted. The results show the 1-D CNN performed well in a limited acceleration range, and network failure occurs when the absolute acceleration of the engine speed is more than 100 r/min/s.

Evaluation of emission characteristics of a stoichiometric natural gas engine fueled with compressed natural gas and biomethane

In this study, the performance and emission characteristics of a stoichiometric natural gas engine were investigated using biomethane and compressed natural gas (CNG). The wide-open throttle (WOT) test and world harmonized transient cycle (WHTC) mode were conducted using a 11 L class six-cylinder natural gas engine that satisfies the emission standards of EURO-6. The biomethane contained 98.69% CH4 content and had a low calorific value of 39.46 MJ/Nm3 owing to the absence of C2–C4 hydrocarbons. In the WOT test, the engine performance deteriorated due to the poor combustion characteristics of biomethane. In particular, the thermal efficiency decreased by 2% when biomethane was used. The high CH4 content of biomethane increased the concentration of oxygenated hydrocarbons at the engine outlet. A total of 72%-76% of non-methane hydrocarbon (NMHC) was oxygenated in the WOT test using biomethane. In the WHTC mode, the emission standards of EURO-6 for nitrogen oxide, carbon monoxide, and NMHC were satisfied using biomethane. However, CH4 and ammonia emissions were higher than those specified in the EURO-6 emission standards when biomethane was used. Fuel consumption with biomethane was also 39.4% higher than that of CNG during the WHTC mode.

Combustion, criteria pollutant and soot property assessment of mixing-controlled high-load engine operation with gasoline and diesel

Gasoline compression ignition (GCI) is an emerging technology that can achieve high fuel efficiency and low criteria emissions in diesel engine platforms using gasoline and gasoline-like fuels. While low- and mid-range loads are enabled with low temperature combustion (LTC) approaches, high-loads are more efficient with high temperature combustion (HTC) requiring mixing-controlled combustion (MCC). Lower soot emissions are achieved with gasoline even in high-load MCC than with diesel, but detailed soot properties from gasoline and diesel have been rarely discussed. In order to better understand how high-load operations affect soot properties, gasoline and diesel were tested in a six-cylinder heavy duty engine at 14 bar brake mean effective pressure (BMEP) at similar combustion phasing. Effects of pilot mass ratio and EGR on heat release rates, cylinder temperatures, ignition delay (ID) and combustion duration (CD) were examined, relating with emissions variations with applications of the two fuels. Soot mass and particle number emissions were slightly lower with gasoline than with diesel, resulting in a more favorable NOx-soot trade-off with gasoline like other reports. Contrary to other findings in the literature, gasoline and diesel soot samples presented similar particle distribution shapes, carbon crystalline structures and primary particle sizes, regardless of fuel type and EGR rate. Consequently, the current result proposes that soot particles have undergone similar soot formation and oxidation processes despite reactivity difference and oxygen availability under the examined high-load MCC with similar combustion phases.

A comparative study of six-cylinder direct injection compression ignition engine fueled with Argemone Mexicana bio-diesel with and without selective catalytic reduction

ABSTRACT The present experimental investigation is related to the performance and exhaust emission parameters of Multi-Cylinder Direct Injection (DI) Compression Ignition (CI) engine fueled with various proportions of Argemone Mexicana (Argemone Mexicana Linn.) with diesel such as 0BD+100D (Neat Diesel), 25BD+75D, 50BD+50D, 75BD+25D, and 100BD+0D (Neat Bio-diesel) at various speed ranges of 1200, 1600, 2000, and 2400 rpm. The present work focuses on reducing the oxides of nitrogen (NOx) by using the Selective Catalytic Reduction (SCR) technique and compared the test results with the Conventional Engine (CE) method at various speed and different blends of fuel. In Conventional Engine, the percentage reduction in brake thermal efficiency for neat biodiesel (B-100) at lower speed and higher speed is 3.49% and 3.07%, respectively, as compared to B-0 and B-25. For B-100, the percentage increase in brake-specific fuel consumption at lower speed and higher speed is 29.16% and 30.01%, respectively, as compared to B-0 and B-25. The percentage reduction in heat release rate for neat bio-diesel is 27.44% at zero degree crank angle as compared to neat diesel fuel. At lower speed (1200 rpm) and higher speed (2400 rpm), the percentage reduction in smoke density is 8.31% and 9.61% for B-25 as compared with B-100, respectively. The percentage reduction in hydrocarbon at lower speed and higher speed is 21.42% and 23.53% for B-0 as compared with B-100, respectively. The percentage reduction in CO for B-25 is 4.17% and 11.43% at lower speed and higher speed, respectively, as compared with B-0. The same trend is observed from the SCR technique method. There is a significant reduction of oxides of nitrogen noted for B-100 with SCR technique at a lower and higher speed of 16.45% and 17.56%, respectively, as compared to Conventional Engine. However, the engine performance such as Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC), Heat Release Rate (HRR), and other emissions such as Hydrocarbon (HC), Carbon monoxide (CO), and Smoke Density (SD), B-25 (25BD+75D) gives better results while compared to neat diesel (0BD+100D) and higher blends for all the speeds in Conventional Engine and Selective Catalytic Reduction technique.

Use of LNG Cold Potential in the Cogeneration Cycle of Ship Power Plants

This paper presents the results of a numerical study on the parameters that affect the efficiency of the cogeneration cycle of a ship’s power plant. The efficiency was assessed based on the excess power (Ngen.) of a free turbine, operated with the inflow of gaseous nitrogen, which was used to generate electricity. A mathematical model and simulation of the regenerative cycle were created and adjusted to operate with a dual-fuel (diesel-liquid natural gas (LNG)) six-cylinder four-stroke engine, where the energy of the exhaust gas was converted into mechanical work of the regenerative cycle turbine. The most significant factors for Ngen. were identified by parametrical analysis of the cogeneration cycle: in the presence of an ‘external’ unlimited cold potential of the LNG, Ngen. determines an exhaust gas temperature Teg of power plant; the pressure of the turbo unit and nitrogen flow are directly proportional to Ngen. When selecting the technological units for cycle realization, it is rational to use high flow and average πT pressure (~3.0–3.5 units) turbo unit with a high adiabatic efficiency turbine. The effect of the selected heat exchangers with an efficiency of 0.9–1.0 on Ngen. did not exceed 10%. With LNG for ‘internal’ use in a ship as a fuel, the lowest possible temperature of N2 is necessary, because each 10 K increment in N2 entering the compressor decreases Ngen. by 5–8 kW, i.e., 5–6%.

Application of Multi-Parameter Fuzzy Optimization to Enhance Performance of a Regulated Two-Stage Turbocharged Diesel Engine Operating at High Altitude

Air intake and fuel supply conditions are the major factors that affect diesel engine performance at plateau. In a regulated two-stage turbocharged diesel engine, these parameters are reflected as the adjustment of fuel injection mass (mfuel), fuel injection advance angle, and bypass valve opening of a high-pressure stage (HP) turbine. Due to the strongly nonlinear nature and complexity of the diesel engine, it is difficult to find the proper parameter combinations. That is why a model-based optimization method is adopted in this paper. The simulation model of a six-cylinder two-stage turbocharged diesel engine is built on the GT-SUITE platform. According to the analysis of diesel engine operation characteristics at high altitude, a fuzzy optimization algorithm is proposed based on a fuzzy logic controller and is realized in a MATLAB/simulink (MATLAB 2014, Mathworks, Natick, MA, USA) environment. Joint optimization of air intake and fuel supply parameters is then performed on the GT-MATLAB co-simulation platform. Results show that engine torque at full load is significantly increased. At the full load point of 2100 r/min, engine power is increased from 256.5 to 319.6 kW, and brake specific fuel consumption (BSFC) is reduced from 243.1 to 222.3 g/(kW·h). Peak torque is increased from 1944.8 to 2173.2 N·m.

Experimental investigation on the characteristics and performance of homogeneous charge induced ignition(HCII) on a multi-cylinder heavy-duty engine

This paper is focused on the characteristics and performance of HCII in conditions close to practical engine operating. For this purpose, extensive experiments have been conducted on a modified six-cylinder heavy-duty diesel engine, with six-cylinder HCII, high pressure exhaust gas recirculation(EGR) loop and appropriate pressure rise rate. The experiments mainly include two aspects. Firstly, gasoline ratio(GR), EGR ratio and start of injection(SOI), are studied to summarize the combustion and emission characteristics of HCII. Secondly, European steady state cycle(ESC) test is conducted to evaluate HCII performance over the whole engine map.Results suggest that large GR is beneficial to effective thermal efficiency(ETE) or/and nitrogen oxide(NOx) and smoke emissions, however, it is limited by maximum pressure rise rate at low load and uncontrollable ignition time at high load. Similarly, the application of EGR can improve gasoline combustion and decrease NOx emission, while it cannot be too much because of decreased ETE at low load and uncontrollable ignition time at high load. Meanwhile, SOI can be advanced to 40 crank angle degree(CAD) before top dead center(BTDC) to achieve extremely low NOx and smoke emissions and relatively high ETE. However, this strategy can only be applied to B25 and C25 points. Finally, great success is achieved by HCII in ESC test. Just with diesel oxidation catalyst(DOC), the weighted specific emissions of NOx, particulate matter(PM), hydrocarbon(HC) and carbon monoxide(CO) can be 1.841 g/(kW·h), 0.024 g/(kW·h), 0.115 g/(kW·h) and 0.896 g/(kW·h) respectively.

Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems

Current commercial and heavy-duty powertrains are geared towards emissions reduction. Energy recovery from exhaust gases has great potential, considering the mechanical work to be transferred back to the engine. For this purpose, an additional turbine can be implemented behind a turbocharger; this solution is called turbocompounding (TC). This paper considers the adaptation of turbine wheels and gearboxes of small turboshaft and turbojet engines into a two-stage TC system for a six-cylinder opposed-piston engine that is currently under development. The initial conditions are presented in the first section, while a comparison between small turboshaft and turbojet engines and their components for TC is presented in the second section. Based on the comparative study, a total number of 7 turbojet and 8 turboshaft engines were considered for the TC unit.

The influence of Fischer–Tropsch-biodiesel–diesel blends on energy and exergy parameters in a six-cylinder turbocharged diesel engine

This investigation explores the influence of oxygenated fuels on different energy and exergy parameters first and the second law of thermodynamics. The parameters were estimated based on the experimental data using thermodynamic Equations. Due to similar fuel properties to diesel, a Fischer–Tropsch fuel (FT100) was used as a base fuel (reference fuel) in the current investigation. Three biodiesel blends were prepared with Fischer–Tropsch fuel. Non-edible Jatropha biodiesel (Jatropha curcas) was selected to avoid food versus fuel conflict. All blends were prepared on a volumetric basis. The first blend was prepared using 25% of biodiesel and 75% of Fischer–Tropsch fuel and termed as B25. The second blend was made with 50% biodiesel and 50% Fischer–Tropsch fuel and designated as B50. The third and the final blend was formulated with 75% biodiesel and 25% Fischer–Tropsch fuel and abbreviated as B75. The three blends were also termed as oxygenated blends as they contain 3 wt%, 5.9 wt% and 8.7 wt%, respectively oxygen content in their molecule. Neat biodiesel (B100) was not targeted in this investigation. A new parameter “oxygen ratio” was used to make a correlation between different energy and exergy parameters with oxygen ratio. Instead of showing different energy and exergy parameters against equivalence ratio or excess air ratio, for better understanding, it is worth showing those parameters with oxygen ratio as all blends are inherently oxygenated. The results show almost insignificant variations in different parameters with the three oxygenated blends when compared to those of the FT100.

Influence of doping Mg cation in Fe3O4 lattice on its oxygen storage capacity to use as a catalyst for reducing emissions of a compression ignition engine

Improving oxygen storage capacity (OSC) of metal oxides by doping with metal cations can produce a catalyst with superior properties to improve engine performance and reduce emissions. In this study, Mg cations were incorporated into a ferric oxide lattice to form Mg0.25Fe2.75O4 via the solution combustion method. The structure, texture, morphology, and oxygen storage capacity of the samples were deeply investigated. The catalytic activity of Mg0.25Fe2.75O4 was finally compared with Fe3O4 as a reference nanocatalyst in terms of its combustion emissions using a six-cylinder Cummins diesel engine. It was found that the doped catalyst presented high crystallinity containing a mixture of the spinel-type crystal lattice and α-Fe2O3 structure, which confirms the ability of the solution combustion method for the fabrication of well-crystalline catalysts. The crystalline structure, surface area, and porosities and vacancy of spinel structure of Mg doped catalyst compared to the inverse spinel structure of Fe3O4 affect OSC of the samples, such that a significant increase in OSC of Fe3O4 (7941 µmol/g) occurred by loading of Mg cations (8661 µmol/g). Based on the engine emissions results, synthesized nanocatalysts are beneficial for decreasing the hydrocarbon (HC), carbon monoxide (CO), and particle mass (PM1.0) emissions. More specifically, the effect of nanocatalysts OSC would be dominated by the impact of increased soot oxidation, leading to PM1.0 reduction.