Engine Performance Research Articles

Selection of propulsion characteristics for systematic assessment of future European RLV-options

AbstractThe propulsion system as the key-element of any space transportation concept is systematically investigated supporting a study on potential future European RLV. Different liquid propellant combinations are compared and evaluated. Subsequently, main stage rocket engines are defined for the two cycle options: open gas-generator and closed staged-combustion. Four different propellant combinations are considered all based on liquid oxygen (LOX) as oxidizer and with the fuel options liquid hydrogen (LH2), liquid methane (LCH4), liquid propane (LC3H8) and kerosene (RP1). These combinations result in eight different generic engines with sub-variants using different nozzle expansion ratios in first and upper stage application. Engine characteristics are similar, as far as conceivable, to be well-suited for the system level comparison of pre-defined RLV-launchers. However, characteristics are not necessarily identical as different engine architectures and propellants might make individual choices necessary. Engine performance characteristics are compared with similar existing engines when available. It is shown that closed-cycle staged combustion engines bring significant performance gains, particularly in sea-level operations. On the other hand, hydrocarbon- and open-cycle gas-generator engines offer a better thrust-to-weight-ratio than hydrogen and staged combustion cycle.

An improved wiener filter-based method for identifying stall inception of transonic compressor

The development of the modern aviation industry poses high demands on the design of aircraft engines recently. However, the stability of compressor flow is one of the key factors affecting further improvements in engine performance. The design of next-generation aircraft engines imposes higher requirements on compressor loading, which leads to the emergence of many new stall inceptions. As a result, the onset and evolution of flow instability become more complex. For accurately capturing stall inceptions of transonic compressors, the strong pressure disturbances caused by shock waves at the blade tip and the complex flow within blade passages result in significant challenges. To address this issue, this study draws inspiration from the design methods of Wiener filters in the field of speech recognition. Based on the characteristic signal mutations during rotating stall in compressors, a Wiener filter approach that uses time-delayed signals as noise estimates during filter training is developed. The method can be used for both offline and online analysis. It was applied to analyze the stall signals of a single rotor from a 1.5-stage transonic axial compressor under distorted inlet conditions at transonic rotational speeds and the entire stage under uniform inlet conditions at subsonic rotational speeds. The results indicate that, under inlet distortion, the compressor generates disturbance signals in the distorted sector before stall, and the earliest spike-inception disturbance occurs at the circumferential position of the rotor leaving the distorted sector. Under uniform inlet conditions, random disturbances could be detected throughout the circumference before stall onset, developing into spike waves at a circumferential location that subsequently triggered stall. Compared to conventional low-pass filters, discrete wavelet transforms, and empirical mode decomposition, the Wiener filter yielded more prominent spike wave structures in the filtered signals. Under distorted inlet conditions, the Wiener-filtered signals showed a 1 % decrease in autocorrelation coefficient and a 3.7 % increase in root mean square (RMS) upon the appearance of spike waves, more pronounced than the 0.5 % decrease in autocorrelation coefficient and 1.8 % increase in RMS achieved by conventional methods. Under uniform inlet conditions, the Wiener filter also detected a 9.7 % increase in RMS upon the appearance of spike waves, more pronounced than the 6.3 % increase observed with conventional methods.

Investigation of operational settings, environmental conditions, and faults on the gas turbine performance

Abstract Gas turbine engines are complex mechanical marvels widely employed in diverse applications such as marine vessels, aircraft, power generation, and pumping facilities. However, their intricate nature renders them susceptible to numerous operational faults, significantly compromising their performance and leading to excessive emissions, consequently incurring stringent penalties from environmental regulatory bodies. Moreover, the deterioration of gas turbine performance is exacerbated by variations in working conditions based on operational settings and environmental conditions. Past studies have focused on certain working conditions that limit effectiveness in real-world applications where operational settings and environmental conditions vary during operations. The influence of these working conditions on the performance of gas turbines also needs to be assessed, as they can lead to different fault patterns resulting in unplanned maintenance, unnecessary maintenance costs, unsafe conditions and stringent penalties. This study uses the gas turbine simulation program to simulate a high-bypass turbofan engine inspired by Pratt & Whitney PW-4056, analysing the combined effects of operational settings and environmental conditions on engine performance while also incorporating simulations of common gas turbine faults like fouling and erosion in various locations and severities along the gas path. The model’s accuracy is confirmed by low mean absolute percentage errors of 0.004% of thrust at the cycle reference point and 0.15% and 0.28% at 2 km and 7 km altitudes, respectively, demonstrating the model’s robustness across varying operational scenarios. In conclusion, this research highlights the significant effects of operational settings and environmental factors on gas turbine performance, particularly impacting specific fuel consumption and thrust. The study reveals that operational settings and environmental factors significantly impact fuel consumption and thrust. Specifically, compressor fouling and low-pressure turbine erosion increase nitrogen oxide (NOx) emissions by 4.5% and 11.1%, while fouling of nozzle guide vanes and high-pressure turbine erosion raise unburned hydrocarbon by 10.0% and 20.2%, and carbon monoxide (CO) by 3.2% and 5.2%, respectively, compared to a healthy engine. These insights highlight the importance of component-specific degradation in influencing gas turbine performance and emissions.

Studies on fuels and engine attributes powered by bio-diesel and bio-oil derived from stone apple seed (Aegle marmelos) for bioenergy

Biofuel is an alternative fuel for diesel engines which is necessary to reduce exhaust emissions and helps to balance the depletion of fossil fuels. This study details the synthesis of bio-diesel and bio-oil from stone apple seeds ( Aegle marmelos) through transesterification, direct oxygenate additive, and pyrolysis processes. The diesel engine is powered by the resulting stone apple methyl ester bio-diesel/diesel and bio-oil/diesel mixtures. In a test engine rig, the effectiveness and emission uniqueness of test fuel mixes were examined at various engine loads (EL = 3 kg–12 kg) and compression ratios (CR = 16–17.5) while maintaining a steady speed of 1500 r/min. Furthermore, engine performance and emissions for bio-diesel and bio-oil are measured and compared. The oxides of nitrogen (NOx) emission by bio-diesel and bio-oil opus were higher than neat diesel (FD). Also, carbon monoxide (CO) and hydrocarbon (HC) emissions were measured to be lower. The improvements of BTE by 4.87% and decrement of CO by 18.8%, HC by 13.26% were observed with the trans-esterified bio-diesel/diesel opus compared to diesel at a higher CR and rated load conditions. The engine analysis responses revealed that the FBD blend showed enhanced performance and lower emissions except NOx compared to diesel fuel. Hence, trans-esterified bio-diesel is a greater diesel alternative than FBDE and FBO.

Comparative analysis of the combustion and emission characteristics of biojet and conventional Jet A‐1 fuel: a review

AbstractConventional jet fuels derived from fossil sources contribute to greenhouse gas emissions and air pollution, leading to climate change. Recent studies have shown that biobased jet fuels from different feedstocks offer a more sustainable alternative to conventional fuels as they are derived from renewable biomass, reducing greenhouse gas emissions. The major feedstocks reviewed are jatropha curcas, camelina, karanja oil, waste cooking oil, and municipal solid waste. They offer diverse benefits for sustainable aviation fuel development. As a comparative analysis, this review examined jet fuel characteristics based on their physicochemical properties, namely energy content, viscosity, calorific value, cetane number, and freezing and flash points. The objective was to understand the influence of the properties on performance evaluation, environmental impact, and combustion characteristics. The properties of biojet fuels are compared with their fossil counterparts to validate their suitability as renewable alternatives and their benefits in terms of emissions reduction and engine performance. Biojet fuels perform better in terms of lower sulfur content, lower soot content, and a lower freezing point, their aromatic content, and their high cetane number. This study enhances the understanding of biojet fuels and their quality, and supports the development of sustainable fuel options. Overall, adherence to the American Society for Testing and Materials (ASTM) D7566‐18 standard is crucial for the acceptance and integration of biojet fuels into the aviation sector. Future research should explore feedstocks such as wood biomass, wastepaper, and agricultural residues for biojet fuels. It should also investigate the combustion and emission characteristics of biosourced aviation fuel at higher blending ratios (>50% by volume) with fossil Jet A‐1.

Tribofilm distribution and tribological analysis of piston ring-cylinder liner interfaces under realistic engine conditions

The study investigates tribofilm distribution and tribology performance on piston ring-cylinder liner surfaces under realistic internal combustion (IC) engine conditions. By examining the effects of load, temperature, and oil film thickness ratio, the research reveals that the tribofilm is significantly greater on the cylinder liner surface compared to the piston ring surface. The findings highlight that a specific excitation pressure is necessary for tribofilm formation. An oil film thickness ratio of 1.8041 is evaluated as an accurate boundary for tribofilm distribution on the cylinder liner surface. These insights provide valuable data for designing piston ring-cylinder liner interfaces and improving IC engine performance.

A simple model for the estimation of turbofan engine performance in all airborne phases of flight

Abstract The overall efficiency of a turbofan engine may be expressed as a function of the Mach number, flight level and one other parameter. This may be either the net thrust, the turbine entry temperature or the fuel flow rate. Using basic aero-thermodynamic principles, dimensional analysis, normalisation and curve fitting, five approximate and “near universal” relations have been identified for engines having bypass ratios between 1 and 13. These relations contain five independent characteristic engine parameters. When these parameters are known, the relations form the basis of an estimation method for engine overall efficiency that is simple, fast, open source, completely transparent and, as new information appears, capable of further refinement. Since the empirical relations presented in this analysis are valid for Mach numbers greater than 0.2, the method is applicable to all airborne phases of flight. For a given aircraft, if the flight trajectory is specified in sufficient detail for the variation of net thrust with Mach number and flight level to be determined, only three of the five relations, together with the value of engine overall efficiency at a single reference condition, are needed to estimate the overall efficiency at every point on the trajectory. Comparisons with the data used in this analysis suggest that the accuracy is better than ±5% in most cases. In the completely general case, two additional engine characteristic parameters, one a total temperature ratio and the other a Mach number, are introduced. If these are known, both engine overall efficiency and net thrust can be expressed as functions of Mach number, flight level and turbine entry temperature. This allows the method to be used for the estimation of operating limits in the various phases of flight and in simplified optimisation studies, e.g. finding the environmentally optimum flight trajectory. In previous work, estimates of engine overall efficiency at the “design optimum” condition have been estimated for 53 aircraft and engine combinations. It is shown that the ‘design optimum’ condition is an appropriate choice for the engine reference condition. Updated and revised values for the relevant parameters for these 53 examples, together with estimates for the two additional engine characteristic parameters, are given in tabular form.

Effect of Piston Geometry on Performance Characteristics of VCR Engine with and without EGR when Fueled with Blends of Methyl Ester

The growing population and exhaustion of fossil fuels necessitate our search for new sources of energy. The study for this research encompasses an amalgamation of interest in alternative fuels, advanced engine technology such as variable compression ratio VCR, engine component modification, and a methodical approach to testing for assessing the effects on key performance of the engine. A 3.5 kW compression ignition (CI) engine was fueled with blends of behada, chicken fat, and turmeric oil methyl ester. Engine operating parameters, such as the compression ratio (CR), rate of exhaust gas recirculation (EGR), and piston top geometry, are optimized to maximize engine performance. CI engine was modified by changing the piston head (square and tangential groove top) for methyl ester diesel blend operations. In the study, diesel fuel is designated as B00 and methyl ester as B20. The influence of compression ratio (CR16 and CR18) with exhaust gas re-circulation (EGR 0% and EGR 10%) was evaluated. The key performance indicators: brake thermal efficiency (BTE), brake-specific energy consumption (BSEC), brake-specific fuel consumption (BSFC), air-to-fuel ratio (AFR), and exhaust gas temperature (EGT) are investigated. Results indicate that an increase in BTE accompanies an increase in load, suggesting enhanced thermal efficiency with increased power output. The consequence of VCR is also investigated, and it is determined that a higher CR results in a higher BTE due to an increase in compression pressure and temperature, thereby enhancing combustion. Due to the re-combustion of unburned hydrocarbons with the addition of EGR at a 10% rate, BTE increases further. Utilizing a piston geometry with tangential grooves and methyl ester blends also contributes to increased BTE. BSEC increases with increasing load, with an important rise observed when operating at maximum capacity. However,at CR 18, BSEC decreases as a result of enhanced combustion efficiency. EGR has different effects on BSEC depending on the geometry of the piston and the kind of fuel used. Enhanced air-fuel blending and re-combustion of unburned hydrocarbons reduce the BSEC of the engine. The tangential groove top piston operates with 10% EGR. Similar to BSEC, BSFC decreases with increasing CR and improves with the use of a piston with a tangential groove and 10% EGR operation. AFR decreases as the consumption of fuel increases to meet the power demand, and higher CR values result in a lower AFR. EGT rises with load, and CR18 has a lower EGT than CR16 as a result of a higher compressing temperature and pressure. 10% EGR operation reduces EGT by decreasing the concentration of oxygen in the combustible area.

Investigation of the performance and emission effects of ammonia-borane as a B–N-based amine-borane adduct in gasoline engines

This study examined the impact of varying concentrations of ammonia-borane (AB) in gasoline on engine performance and emissions across different load conditions. Four fuel formulations were tested: pure gasoline (G100) and gasoline blends containing 10%, 15%, and 20% AB (AB10, AB15, AB20). Increased AB concentration resulted in higher brake-specific fuel consumption (BSFC). While exhaust gas temperatures were highest with G100 (730.9 °C at full load), the AB blends, particularly AB20, exhibited lower temperatures, with a maximum reduction of 13.8%. The AB20 blend demonstrated elevated BSFC and increased oxygen (O₂) emissions but significantly reduced carbon monoxide (CO) emissions, with up to an 88.2% decrease at full load. Nitrogen oxide (NOx) emissions were generally lower for all AB blends. The highest NOx value was measured with G100 fuel at full load, while the lowest NOx value was measured with AB10 fuel. Under these conditions, a 23% decrease in NOx value was observed with AB10 fuel compared to G100. The engine's thermal efficiency decreased with AB blends at all load levels compared to pure gasoline. Thermal efficiency decrease of 13.76%, 22.32%, and 30.88% occurred for AB10, AB15 and AB20, respectively compared to G100.Overall, incorporating AB in gasoline reduced thermal efficiency and led to a notable decrease in NOx, hydrocarbons (HC), and CO emissions.

High-temperature deposition model for molten particle prediction based on droplet-surface interaction criteria

Particle deposition in gas turbine engines damages blade surfaces and diminishes engine performance. Deposition results from heat and momentum exchanges between fluid and particles, coupled with the interactions between particles and surfaces. The increasing turbine inlet temperatures cause particles to become molten, complicating their interaction with surfaces. Existing models fail to convincingly explain the deposition behaviors of molten particles. In the present study, considering particle fluidity and the nonlinear accumulation of deposits, the deposition criteria for viscous droplets and the maximum steady deposit layer model were incorporated to establish an unsteady high-temperature deposition model. The new model, validated against experiment results in the literatures, predicts molten particle deposition behavior with an average error of 3.89 % in capture efficiency at high-temperature conditions. It accurately predicts crown-like deposit morphology and nonlinear accumulation, matching experimental observations. Applied to nozzle guide vanes with film cooling, results show that deposits primarily occur on the leading edge and pressure side near the trailing edge. The particle capture efficiency initially rises before diminishing as particle size increases, whereas an inverse trend is noted with the escalation of the mass flow ratio. At a mass flow ratio of 0.15, the capture efficiency hits the minimum of about 13.2 %.

Experimental investigation of the effects of aqueous ammonia and water mixtures on the efficiency and emissions of a compression ignition engine

In this study, different concentrations of aqueous ammonia and pure water were fumigated and aspirated into the cylinder from the engine intake manifold. Aqueous ammonia (NH4OH) with 5 %, 10 % and 15 % ammonia (NH3) concentration was used in the experiments. Both aqueous ammonia and pure water were converted into cold vapor using an ultrasonic evaporator and conveyed to the combustion chamber as fume. Experiments were carried out at a constant engine speed of 660 rpm. Torque values of 25 %, 50 %, and 100 % (386 Nm) were used in the experiments, respectively. As a result of the experiments, it was seen that as the ammonia percentage increased, the engine efficiency was negatively affected. At 100 % torque, when comparing the BTE value of pure diesel fuel with the BTE values of experiments with 5 %, 10 %, and 15 % ammonia addition, decreases of 0.09 %, 2.27 %, and 3.57 % were observed, respectively. In experiments conducted with pure water, although the thermal efficiency increased significantly as the torque ratio increased, it still could not reach the thermal efficiency of pure diesel fuel. On the other hand, it has been observed that water vapor improves NO and HC emissions. While the NOx value tends to increase with the increase in ammonia concentration at low and medium load values, the NOx value tends to decrease relatively as the ammonia concentration increases at 100 % torque value. The highest NOx emission value, 534 ppmvol, occurred in the experiments with 15 % NH4OH addition. It was observed that the NOx emission value of all experiments conducted with aqueous ammonia additive at 100 % torque was lower than pure diesel. In this study, the effects of NH4OH and H2O on engine performance and emissions were investigated.

Effect of Fuel Injection Parameters on Engine Performance in A Conventional Single Cylinder Spark Ignition Engine

In this study, a 1D model was created using the Ricardo-Wave program for a single-cylinder, spark ignition, four-stroke, direct injection engine with a stroke volume of 398 cc. Air-fuel ratio (AFR), mixture temperature (MT), and start of injection (SOI) were used as fuel injection parameters. Using these parameters, 343 different cases were created. Brake power, thermal efficiency, and fuel consumption were used as engine performance parameters. By holding one injection parameter constant, a contour plot was created to examine the effect of the other two parameters on the engine performance parameter. According to the results, the effect of MT and SOI on brake power is 1%, the effect of AFR on brake power is 9.6%, the effect of MT and SOI on thermal efficiency is 1%, and the effect of AFR on thermal efficiency is 12.8%. The effect of MT and SOI on fuel consumption is 0.04%, the effect of AFR on fuel consumption is 22.9%, and the effect of AFR on brake specific fuel consumption is 22.9%. These results indicate that the most significant effect is provided by AFR, while MT and SOI also have a slight impact on engine performance.

An experimental investigation on performance, emission and combustion characteristics of IC engine using liquid fuel produced through catalytic co-pyrolysis of pressed oil cake and mixed plastics with the addition of nanoparticles

The study focuses on using a combination of diesel and a liquid fuel derived from the co-pyrolysis of pressed neem cake (PNC) and mixed waste plastics (MWP) containing waste polyethylene terephthalate (PET) and low density polyethylene (LDPE) in equal amounts with the help of cupric oxide (CuO) catalyst. The engine analysis was carried out using diesel and five different blends of co-pyrolysis oil with diesel in proportions of 20 % (20 % pyrolysis oil + 80 % diesel = PD20), 40 % (PD40), 50 % (PD50) and 100 % pyrolysis oil (PD100), respectively. Initially, the co-pyrolysis oil was produced using PNC and MWP in a ratio of 1:2 under different operating temperatures between 350 °C and 650 °C. The process temperature was optimized to yield maximum liquid oil, and the characterization study was performed. In addition to that, CeO2 nanoadditives were used to improve the properties of PD20 fuel. Different dosages of nanoadditives were blended with PD20 to prepare PD20@25 (PD20 + 25 ppm CeO2), PD20@50, PD20@75, and PD20@100. The objective of the study is to assess the performance, emission, and combustion characteristics of a diesel engine utilizing co-pyrolysis oil-diesel blend by including the nanoadditives. The analysis was carried out on a single-cylinder water-cooled diesel engine mounted with an eddy current dynamometer. The experiments demonstrated that the combination of PD20 and 50 ppm CeO2 resulted in a 6 % increase in thermal efficiency when compared to other blended fuels and diesel. When compared to all fuels, the PD20@50 produced a higher decrease in CO and HC emissions by roughly 30 and 6.2 %, respectively. The combustion analysis showed that the heat release rate (HRR) and maximum cylinder pressure were also found to have improved by adding nanoparticles.

Neural network-based self-tuning control for hybrid electric vehicle engines

Combustion engine speed control faces significant uncertainties in parameters like mass equivalent coefficient and efficiency. To address these challenges, this research develops an adaptive, self-tuning artificial neural network (ANN) control design that aims to optimize engine speed despite load torque and model uncertainties. We integrate three controllers—linear quadratic regulator (LQR), proportional-integral-derivative (PID), and sliding mode controller (SMC)—with machine learning techniques to evaluate their performance in hybrid electric vehicle engines. The ANN-based self-tuning controller identifies the most effective method for maintaining idle engine speed with minimal deviation. The results indicate that the ANN can accurately predict settling times and enhance controller performance, leading to reduced settling time errors, improved fuel economy, and better emissions performance. The study highlights LQR's high sensitivity in the lower settling time range and reduced sensitivity in the higher range, the PID controller's varied sensitivity, and SMC's consistent sensitivity across both ranges. A well-trained ANN is essential for optimizing control parameters and maintaining system stability. The ANN was trained and validated using the nntool MATLAB toolbox, with tests conducted across lower and higher settling time ranges. Results showed that the PID controller's performance was overfitted by insufficient training in the lower range, while the LQR and SMC demonstrated potential for more efficient control in both ranges. Overall, the study underscores the importance of a proficiently trained ANN for achieving precise control in hybrid electric vehicle engines.

Design, Development and Mission Performance of Throttleable Engines of Chandrayaan-3 Lander

Design, Development and Mission Performance of Throttleable Engines of Chandrayaan-3 Lander

Multi-body dynamics modeling and energy consumption optimization of electromagnetic mechanical fully variable valve system

Electromagnetic Mechanical Variable Valve Actuation (EMVVA) technology has the capability to improve engine performance and decrease pollutant emissions. A new type of EMVVA composed of electromagnetic driver and mechanical transmission is proposed to realize the flexible adjustment of valve parameters whether the valve is open or closed process. The geometric mathematical model of the mechanical transmission is developed based on the motion laws of the valve and the geometrical construction of the mechanical transmission, and the conjugate cam curve is solved. A multi-body dynamic model is constructed to calculate the driving torque and energy consumption needed by the mechanical transmission based on the mass, rotational inertia, centroid position of the parts, combining the normal contact force model and the friction model of the clearance contact pair at the same time. Based on the geometric model and multi-body dynamics model, the test platform is established. The test results demonstrated that within the specified valve lift, EMVVA system could accomplish variable valve lift, variable valve timing, and variable valve duration at maximum lift. The maximum timing error does not exceed 1° crank angle, and the maximum valve lift error does not exceed 0.25 mm at 11 mm valve lift. In addition, the error of driving torque between the multi-body dynamics model and the test is less than 0.3 [Formula: see text].Low energy optimization of mechanical transmission was completed using the NSGA-II method and multi-body model. According to the results of the optimization, energy consumption was reduced by 14%, and the peak driving torque was decreased by 54.3%.

Enhancing diesel engine performance and emissions control with reduced Graphene oxide and Non-Edible biodiesel blends

The growing concern about environmental degradation and the depletion of fossil fuel supplies has prompted experts to investigate alternate and sustainable transportation energy sources. In these circumstances, biodiesel made from renewable feedstock has emerged as a viable environmentally friendly alternative to conventional diesel. This study thoroughly examines the performance and emission characteristics of a 4-stroke diesel engine running on biodiesel blends, including reduced graphene oxide (rGO) nanomaterial. The non-edible biodiesel from the Jatropha curcas plant is utilized, and it is blended in various ratios with conventional diesel, ethanol, and nanomaterial rGO to improve performance and emissions parameters. Torque increased by up to 17 % in rGO DJE02GO25 at 3500 rpm, while Brake Power decreased by 6.3 % in rGO DJE01GO25 at 2600 rpm. Brake Thermal Efficiency decreased by 12.5 % in rGO Blend 1 at 2600 rpm, and Brake-specific fuel consumption decreased by 16.5 % in rGO DJE02GO25 at 3500 rpm. CO2 emissions decreased up to 19.71 % in rGO Blend 10 at 2600 rpm. HC emissions decreased to 94 % in rGO blend 8 at 3500 rpm. Finally, NOx emissions decreased up to 84.78 % in rGO Blend 1 at 2900 rpm. The current study reveals that after adding rGO nanomaterial in biodiesel, there is a significant decrease in NOx and HC emissions.

RESEARCH OF THE COMBUSTION PARAMETERS OF GASOLINE WITH ADDITIONAL HYDROGEN IN A SPARK-IGNITION ENGINE IN EXTERNAL SPEED CHARACTERISTIC MODES

The directions of development and improvement of road transport around the world are inextricably linked to the desire to reduce the use of cars “on traditional fuels” due to limited oil and environmental safety of mankind. Since the modes of external speed characteristic are the most typical for the operation of cars in cities, the study of environmental performance of engines in these modes is an urgent task. Therefore, finding ways to reduce carbon dioxide emissions from automobile engines at high-speed modes is an urgent task. The rapid growth in the number of cars with internal combustion engines and the inevitable decline in world oil reserves necessitate the development and implementation of energy-saving technologies and the use of alternative fuels. Research aimed at finding ways to improve the fuel efficiency and environmental performance of automotive engines is relevant. One of the promising areas is the influence on the combustion process in gasoline engines by using additives of alternative fuels, which include hydrogen. The presented study of the parameters of combustion of gasoline with hydrogen additive in a spark ignition engine at external speed characteristics is a comprehensive analysis of the combustion process of a gasoline-hydrogen mixture and determination of its effect on the concentration of carbon dioxide in exhaust gases by developing a mathematical model that takes into account the composition of the mixture components and features of the combustion process, allows for sufficiently accurate calculation of the operating process of an engine with hydrogen additive at ψ ≤ 10%, its identification by the results of experiments. In the course of the study, dependencies were developed to determine the combustion parameters of the Wiebe model, taking into account the addition of hydrogen to gasoline in the modes of external speed characteristics, and the effect of hydrogen addition on the concentration of CO2 in exhaust gases was analyzed. It is shown that with an increase in the hydrogen additive to 10% by mass fraction to gasoline, there is a decrease in CO2 emissions to almost 30% in the external speed characteristic modes, which corresponds to modern environmental standards for gasoline internal combustion engines.

The performance of a spark ignition gasoline engine with hydrogen addition under low-load conditions

With continuously increasing populations and industrialization, more and more green consumers and stringent emission regulations promote low-carbon or zero-carbon alternative fuels in transportation sector. Hydrogen is considered carbon-free when produced using environmentally friendly methods, and could achieve zero carbon emission in the internal combustion engines. This study comprehensively explores the influences of the hydrogen addition on the performance of the gasoline spark ignition (SI) engine operated at low-load conditions. The experimental results showed that the abnormal combustion cycles of the test gasoline engine are greatly reduced with hydrogen enrichment. In addition, the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) of the gasoline engine is 2.66 % under the 1500 rpm and 0.2 Mpa (brake mean effective pressure: BMEP) condition, while the COV of IMEP of the engine fuelled with gasoline and hydrogen is 2.34 % at the same condition. Furthermore, the knocking intensity of the gasoline engine is strengthened by adding hydrogen because the averaged maximum pressure rise rate (MPRR) of the gasoline SI engine is slightly increased. Besides, the indicated thermal efficiency (ITE) of the gasoline engine is increased 0.9 % and its maximum increase rate of the ITE is 4.27 % with hydrogen addition at the 1300 rpm and 0.2 MPa condition. Last, unburned HC, CO, and CO2 of the gasoline engine are reduced while NOx emissions increase with adding hydrogen due to high combustion temperature.

Improving the Performance of Natural Gas Engine at High Altitude Based on Response Surface Method and NSGA-II Optimization

Improving the Performance of Natural Gas Engine at High Altitude Based on Response Surface Method and NSGA-II Optimization