Cylinder Pressure Research Articles

Impacts of novel calotropis gigantea seed biodiesel usage as a fuel substitute along with various metal-oxide nanoparticles on the DICI engine characteristics

Calotropis gigantea, commonly known as Indian milkweed, is a prevalent plant in Asia. It typically thrives in open and unused areas, often considered a weed. This plant produces flowers and fruits consistently throughout the year, exhibiting a continuous flowering and fruiting cycle. This research investigated the viability of Calotropis gigantea seed oil as a potential source intended for biodiesel manufacturing. The oil was obtained from Calotropis gigantea seeds using hexane extraction in the Soxhlet apparatus. The seeds were determined to contain 33.3 wt% of oil content. The process of biodiesel production involved conducting a transesterification reaction. Further, the produced biodiesel was blended with pure diesel and three different nanoparticles, Titanium dioxide (TiO2), Chromium oxide (Cr2O3), and Silicon dioxide (SiO2), to evaluate combustion performance, and emission characteristics of a single-cylinder diesel engine under various load conditions. Incorporating Cr2O3 nanoparticles into the CGSB20 biodiesel blend yielded significant improvements in BTE, coupled with BSFC reduction. Specifically, in the CGSB20 + Cr2O3 fuel mixture, BTE increased notably by 31.2 %, reaching a value of 0.33 g/kWh for BSFC. Similarly, for the CGSB20 + SiO2 and CGSB20 + TiO2 blends, BTE experienced enhancements of 29.2 % and 28.1 %, respectively, while BSFC values were lowered to 0.37 and 0.4 g/kWh. Furthermore, the unchanging dispersal of nanoparticles within the CGSB20 blend exhibited extraordinary cylinder pressure and HRR values, reaching 77 bar and 34.2 J/CA, respectively. The CGSB20+ Cr2O3 blend yielded favorable emissions outcomes. Specifically, CO, NOx, UHC, and smoke emissions were approximately 4.5 g/kWh, 725 ppm, 0.11 g/kWh, and 23.6 %, respectively.

Application of acetylene in multi-cylinder low heat rejection diesel engine fueled with ternary blend

The depletion of fossil fuels and environmental degradation have driven researchers worldwide to seek suitable alternative fuels for diesel engines. Internal combustion engines typically emit carbon monoxide (CO), hydrocarbon (HC), and smoke, contributing to environmental pollution. To address this issue, petroleum fuels can be substituted with alternative options like acetylene gas, hydrogen, CNG, or LPG. One effective strategy is to incorporate renewable fuels into diesel engines by partially or fully replacing diesel in a dual fuel mode (DFM). This research focuses on alternative renewable fuels for diesel engines like biodiesel and alcohol and its blends. The current research investigates the engine characteristics of diesel engines fueled with ternary blend (TB) fuel and different flow rates of acetylene in DFM. TB fuel was prepared using 70 % diesel, 20 % waste cooking oil biodiesel (WCOB), and 10 % methanol by volume. The induction of acetylene at different flow rates, such as 2, 4, and 6 lpm. Waste cooking oil is used to prepare biodiesel by transesterification. Partially stabilized zirconia (PSZ) is used to coat the cylinder head, piston crown, inlet, and exhaust valves with a thickness of 0.5 mm. The HC, CO, and smoke emissions are decreased by about 35.7 %, 29.8 %, and 21.6 %, respectively, for TB fuel with acetylene at 6 lpm at full load condition. The high calorific value of acetylene gas raised the in-cylinder temperature, significantly accelerating the combustion process. The heat release rate (HRR) and cylinder pressure are increased by 9.8 % and 6.8 %, respectively, at TB fuel with 6 lpm of acetylene induction. Acetylene induces rapid fuel combustion, resulting in increased energy transfer. The brake thermal efficiency (BTE) is improved by about 10.3 % for TB fuel with acetylene at 6 lpm and exhaust gas temperature (EGT) increased to 461oC at full load condition.

Computational investigation of combustion and emission characteristics of HCCI engine fueled with Carbon-Free NH3 –H2O2 blend

A computational investigation is provided of the utilization of blends of NH3 and H2O2 as carbonless fuels for HCCI combustion. A Computational Fluid Dynamics (CFD) model is developed and validated to assess the engine’s performance under varying proportions of NH3 and H2O2, equivalence ratios, and inlet temperatures. The heat release rate profiles demonstrated dual peaks, which were rationalized as an initial fuel decomposition followed by a slow thermal explosion and then a fast depletion of the fuel after the generation of a pool of OH radicals through decomposition of H2O2. Findings suggest that an increase in mole fraction of H2O2 advances combustion. Increasing the H2O2 volume fraction also decreases combustion duration, while increasing the IMEP. In-cylinder peak pressure and Maximum Pressure Rise Rate (MPRR) increase with H2O2 mole fraction, leading to reduced thermal efficiency, particularly at higher equivalence ratios, and an increased danger of uncontrolled combustion (knocking). Additionally, higher inlet mixture temperatures were shown to result in an advancement in the start of combustion and a reduction in combustion duration, with a corresponding increase in peak pressure. This points to the possibility of potentially controlling the notoriously difficult-to-control HCCI combustion through intake temperature for NH3/H2O2 fuel blends. However, increased NOx emissions are observed for increased intake temperature and in any case the NOx emissions are orders of magnitude above current regulatory limits, which means that practical engine operation will only be possible with an aftertreatment scheme based on the de-NOx activity of NH3.

Characterization of pressure oscillations and combustion noise of hydrogen reactivity-controlled compression ignition (RCCI)

Knock and combustion noise are the main reasons limiting the increase in hydrogen (H2) replacement rate in H2 reactivity-controlled compression ignition (RCCI). This study aims to identify the knock-dominated mechanism and elucidate the characteristics of knock and combustion noise of H2 RCCI operated at a broad range of parameters through the combined analysis of the heat release profile and pressure oscillations. The results indicated that under inhomogeneous heat release conditions, the onset of pressure oscillations is mainly attributed to the local fast heat release at the initial combustion stage, but for the conditions with relatively homogeneous and high-reactivity mixture, the pressure oscillations are primarily excited by the end-gas autoignition. Compared with the single injection strategy, the double injection strategy with the first and second start of injection of −60 and −15°CA ATDC (SOI1/2 = −60/-15°CA ATDC) can effectively mitigate the pressure oscillations and shorten the propagation period of pressure waves. However, as the SOI2 is advanced to −30°CA ATDC, the pressure oscillations dramatically increase, because the enhanced fuel reactivity of premixed H2 exacerbates the end-gas autoignition. The results of frequency analysis of in-cylinder pressures show that with the increase in inhomogeneous combustion, the first resonance frequency reduces. As the intake pressure (Pin) is raised from 1.2 to 1.6 bar, the first resonance energy increases, since the elevated in-cylinder temperature associated with the piston compression during the compression stroke enhances the propagation and development of pressure waves. The high-order resonance is closely related to the autoignition of end gas with higher fuel reactivity. Overall, the combustion noise shows a good linear correlation with peak heat release rate for all the points investigated in this work, but the linearity of H2/polyoxymethylene dimethyl ethers RCCI is better than that of H2/diesel RCCI. Moreover, with the increase in Pin, the engine noise associated with the piston compression increases.

Enhancing engine performance, combustion, and emissions characteristics through CeO2-modified cottonseed biodiesel with hydrogen enrichment: A comprehensive investigation

This investigation delves into the combined use of nanoparticles added biodiesel blends and hydrogen as secondary fuels in CI engines, intending to minimize the reliance on traditional fossil fuels. Calcined wood ash (CWA) has been used as a heterogeneous catalyst for the preparation of cottonseed biodiesel. XRD, SEM and BET analysis was performed to characterize the catalyst. This study evaluates the impact of adding hydrogen and Cerium oxide (CeO2) nanoparticles to cottonseed biodiesel on a CRDI engine. It showed that H2 at an intake rate of 10 L/min improved the engine's overall performance and reduced hazardous emissions. By incorporating the CeO2 nanoparticles (75 ppm) in a cottonseed biodiesel blend and injecting H2 in the engine the BTE was enhanced by 27.8% and BSFC was decreased by 4.41%. There was a reduction of 24%, 22.8%, 6.42%, and 69.5% for HC, CO, CO2 and smoke emissions. On the other hand, NOx rose by 9.3% compared to diesel. The combustion characteristics, such as cylinder pressure showed 26.5% improvement at full load on inclusion of H2. Additionally, under maximum load, the blend C20 + CeO2+H2 has the shortest ignition delay and combustion duration leading to higher engine efficiency. The results of this investigation offer valuable insights into the potential of biodiesel-hydrogen dual-fuel strategies to reduce the environmental impact of CI engines while promoting sustainable energy practices.

Evaluating Ammonia-Diesel Blends in Engine Operations: Performance and Stability Impacts

Abstract This study investigated the effects of incorporating ammonia into diesel engine operations, focusing on its impact on performance and stability. Ammonia was introduced into the engine via the intake air. By varying ammonia ratios at different engine speeds and under full load conditions, it was found that ammonia integration could be achieved without stability issues up to an energy fraction of 54%. However, exceeding this threshold resulted in misfire occurrences during engine operation. Notably, lower energy ammonia fractions below 40% led to increased power output, while higher fractions caused power reduction. Additionally, consistent reductions in brake-specific energy consumption were observed with ammonia supplementation. Variations in in-cylinder pressure were directly correlated with power output changes. Peak pressure initially increased with ammonia but decreased beyond 40% energy sharing, with its location consistently retarded. Moreover, ammonia induction led to longer ignition delays and altered combustion phasing across all engine speeds, indicating its significant influence on engine operating parameters.

Investigations on performance of gasifier engine integration using three different biomasses as feedstocks

The integration of a downdraft gasifier with modified internal combustion engines presents a feasible solution for heat and power production, such as off-grid areas. This study conducted an experimental analysis to evaluate combustion in a modified engine. The morphological characteristics of the agricultural residue used in the gasifier were analyzed using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM), along with an examination of the slagging inorganic constituents. The engine used in the experiments was a modified single-cylinder design paired with a downdraft gasifier. Three types of biomass feedstocks—eucalyptus, corncob, and pearl millet in pellet form —were tested. The performance of the downdraft gasifier was stabilized, and the engine was run independently on each type of producer gas at a constant speed under different loads to determine the optimum load. Cylinder pressure measurements were taken to estimate the heat release rate.The study found that power generation was lower than typical woody biomasses due to the lower calorific value of the producer gas from the tested feedstocks. Additionally, lower cylinder pressures and heat release rates were recorded, along with longer combustion durations. The varying proportions of producer gas affected combustion stability. Among the studied ashes, pearl millet corncob (PMC) exhibited the highest slagging tendency, followed by corncob (CC). Morphological analysis indicated that the eucalyptus residue's increased porosity was caused by the volatiles changing, forming pores and tube-like structures. An aliphatic C–H peak (3000–2500 cm⁻1) is absent from the residue, indicating that the aliphatic structure was disturbed during thermochemical conversion. During the gasification process, the residue's crystallinity reduced as it split down.

The physical information LSTM surrogate model for establishing a digital twin model of reciprocating air compressors

Reciprocating air compressors play a crucial role in industrial production processes. However, due to the complex structure and long operating time of reciprocating air compressors, real-time monitoring to grasp the operating status of reciprocating air compressors has become particularly important. Digital twin is a technology that can reflect the behavior of physical entities in real time, accurately predicting and evaluating the operation status of reciprocating air compressors. However, the establishment of a digital twin model for reciprocating air compressors requires a significant amount of computational resources, which can result in the inability to meet the requirements of real-time performance evaluation. To overcome this limitation, this paper proposes a method for constructing a digital twin model of reciprocating air compressors based on a surrogate model. The surrogate model is constructed based on a long short-term memory neural network with physical information(PILSTM). This model can accurately describe the changes in cylinder pressure by combining physical information. According to the characteristics of cylinder pressure changes, regularization formulas are added to ensure the smoothness of the predicted pressure. The experimental results show that the digital twin model based on the surrogate model has high prediction accuracy and real-time performance. Therefore, this model provides a new method for monitoring the operating status of reciprocating air compressors.

Synthesis and characterisation of waste-derived biodiesel and enhancement of its energy and environmental metrics using cetane improver: an experimental study

The primary objective of this study is to produce Bauhinia monandra biodiesel (BMB) using seed waste and improve its energy and environmental properties by integrating a cetane enhancer. The methyl ester of biooil was obtained using the transesterification method, and the properties were analyzed. Different quantities of BMB were combined with diesel fuel, and 2-ethyl hexyl nitrate (EHN) was introduced to the blend of 30% BMB-diesel fuel to improve both energy and environmental performance measurements. The research findings indicate that the FAME and physicochemical properties of BMB are comparable to those of diesel fuel. The brake thermal efficiency (BTE) of the engine decreases by 4.2% for 30% BMB blended fuel, whereas hydrocarbon (HC), carbon monoxide (CO), and smoke emissions decrease by 11.6%, 6.7%, and 10.5%, respectively. As the concentration of BMB increases, there is a reduction in both the maximum value of in-cylinder pressure and the net heat release rate. Conversely, brake-specific fuel consumption (BSFC) and NOx emissions increase by 5.7% and 4.7%, respectively. The incorporation of EHN in the test fuel enhances BSFC and BTE by 4.2% and 4.3%, respectively, whereas NOx, HC, and CO emissions are reduced by 5.2%, 9.2%, and 9.9%, respectively.

Investigation of fuel temperature and injection timing effects on ammonia direct injection in an optical engine

This work investigates the effects of fuel temperature and injection timing on ammonia direct injection in an optical engine using a multi-hole injector. Flash-boiling may occur over various engine-relevant conditions due to ammonia’s high vapor pressure. This phenomenon impacts spray characteristics and, in severe cases, facilitates cavitation inside the nozzle. Both fuel temperature and injection timing (i.e., ambient conditions during injection) impact the intensity of flash-boiling during fuel injection. Therefore, this work varies fuel temperature (from 320K to 388K) and injection timing (from −60CADaTDC (crank angle degrees after top dead center) to −6CADaTDC) to assess their impact on injection mass flux, discharge coefficients, and macroscopic spray characteristics using an ammonia injection pressure of 200bar. For this purpose, the injection mass is measured by analyzing exhaust gas compositions during engine operation with ammonia injections but without combustion. In addition, diffuse background illumination (DBI) images capture the liquid phase of the fuel spray to characterize spray behavior. The findings reveal that increasing fuel temperature decreases ammonia’s injection mass by up to 12.8% but has little impact on discharge coefficients for late injection timings and high in-cylinder pressures. However, discharge coefficients decrease by up to 17.4% (from 0.58 to 0.48) for early injection timings if fuel temperatures are high. The individual sprays of the 6-hole GDI injector may collapse into a uniform spray at high-density conditions without flash-boiling or under strongly flash-boiling conditions. The findings clarify the impact of ammonia’s high vapor pressure on injection mass and prove the relevance of different spray collapse mechanisms in ammonia direct injection engines.

Effects of Magnetic Fields and Nanoparticle Additives on Diesel Engine Emissions and Performance: A Comprehensive Experimental Analysis

T. In the present study, performance and emission changes in a compression ignition engine were investigated by combining two methods. The first method involves adding nanoparticle additives to diesel fuel. Titanium dioxide (TiO2) with a particle size of 21 nm was used as nanoparticle. TiO2 was added to diesel fuel at doses of 50 mg and 100 mg per 1 kg (50 and 100 ppm). After adding the nanoparticle to the diesel fuel, each mixture was stirred with a mechanical stirrer for one hour. In the second method, a magnetic field of 1 tesla was created around the fuel. Neodymium magnets were placed circularly around the diesel fuel line to create the magnetic field. The experiments were carried out at 660 RPM engine speed and 100% torque. During the experiments, data on engine performance, in-cylinder pressure and emissions were recorded. This study aims to contribute to the development of alternative fuel applications to improve performance and emissions in compression ignition engines.

Investigation of high percentage of dimethyl ether on biodiesel usage in a diesel engine

Demand for cleaner energy sources both as additive and alternative fuels that can substitute or contribute to the usage of conventional fuels is growing. Researchers have mainly focused on improving or finding a renewable fuel from vegetable oil or addition of chemicals and alcohols for IC engine. This study analyzed the effects of a high percentage of dimethyl ether (DME) combined with biodiesel in a diesel engine. Transesterification method was selected for conversion of pure safflower oil to biodiesel. DME was blended with biodiesel at concentrations of 50% and 25% on a volume basis, respectively. Engine performance and emissions tests demonstrated that the thermal efficiency values were increased at high load operation when the engine was fueled with high percentage of DME. Furthermore, compared to conventional diesel, there has been a notable decrease in NOx emissions. Nevertheless, the introduction of DME blend had negligible effects on CO2 emissions. However, when using a high ratio of DME blend, HC emissions were found to increase, whereas a low ratio of DME blend resulted in decreased HC emissions. Apart from these, some irregularities were observed both on heat release rate and cylinder pressure especially for 50% of DME usage. Finally, the values for both brake-specific fuel consumption and mass fuel of DME-blended fuels were deteriorated.

Study on the impacts of injection parameters on knocking in HPDI natural gas engine at different combustion modes

Based on three-dimensional (3D) computational fluid dynamics (CFD) software, a 3D numerical model was constructed to investigate the effects of injection timing, pilot diesel energetic ratio (PDER), and angle between the central axis of the diesel jet and the horizontal direction (α) on combustion and knock in the natural gas mixing-limited combustion (NMLC) mode and natural gas slightly premixed combustion (NSPC) mode. The results indicate that advancing the start of injection of natural gas (NSOI) leads to a slight improvement in indicated thermal efficiency (ITE), but also an increase in peak cylinder pressure (Pmax) and maximum pressure rise rate (MPRR). In the NMLC mode, as the diesel and natural gas injection interval (IDN) decreases, the interference between the diesel and natural gas jets intensifies, ultimately leading to instability in the flame propagation process and increased fluctuations in cylinder pressure. At different NSOIs, when IDN is 0°CA, the maximum amplitude of pressure oscillations (MAPO) is the highest. When the PDER is increased from 5 % to 15 %, ITE increases by 7.1 %. Under different combustion modes, as α increases, ITE first increases and then decreases. However, the NSPC mode achieves a higher ITE, reaching up to 44.4 %.

Analysis of transmission pathways of combustion-induced vibration in a diesel engine using wavelet cross-correlation analysis method

We experimentally investigated the transmission pathways of the combustion-induced vibration by analyzing the in-cylinder pressure, the accelerations on walls near the combustion chamber and the main bearing with wavelet cross-correlation analysis which can obtain both time delay and the correlation on the time between two signals in the frequency domain. The analysis shows that there are three possible transmission pathways of vibration from the combustion impact. First is a direct transmission from the combustion chamber to a wall near the combustion chamber or a wall near the main bearing via an engine surface wall, second is the transmission from the combustion chamber to a wall near the main bearing via the piston, connecting-rod and the crankshaft, and third is a transmission from the combustion chamber to a wall near the main bearing and there is no transmission to a wall near the combustion chamber.

Kinetic and optimization study of ultrasound-assisted biodiesel production from waste coconut scum oil using porous CoFe2O4@sulfonated graphene oxide magnetic nanocatalysts: CI engine approach

In this study, CoFe2O4@sulfonated graphene oxide (SGO) heterogeneous nanocatalyst was synthesized and utilized to produce biodiesel from waste coconut scum oil (WCSO). The structural features of CoFe2O4@SGO nanocatalyst were evaluated by SEM, TEM, EDX, FTIR, XRD, CO2/TPD, VSM, and BET analyses. According to these analyses, CoFe2O4@SGO nanocatalyst has high specific surface area, suitable functional groups, and good reactivity. The highest biodiesel yield using CoFe2O4@SGO nanocatalyst in optimal conditions (MeOH/WCSO ratio = 12.41, temperature = 64.73 °C, catalyst concentration = 2.24 %, and ultrasonic time = 33.08 min) was 96.87 %. The yield of biodiesel decreased from 96.91 % to 90.17 % after six reuse cycles, which demonstrates the significant stability of CoFe2O4@SGO nanocatalyst in the transesterification process. After 7 reuse steps, XRD and CO2/TPD analyzes revealed that the catalytic activity and crystallinity of the nanocatalyst were almost retained. The kinetic behavior of biodiesel generation showed that the transesterification reaction is endothermic. Enhancing the concentration of biodiesel in the fuel mix had a positive impact on the reduction of CO and UHC emissions, as well as diesel engine parameters such as cylinder pressure, BP, EGT, BSFC, and BTE. Owing to the high biodiesel yield, significant reusability, and positive impacts on the diesel engine, CoFe2O4@SGO nanocatalyst is recommended for industrial applications.

Research on combustion cycle-by-cycle variations under high load in SACI mode and application potential of i-EGR coupling air dilution when fueled with methanol and gasoline

Spark assist compression ignition (SACI) is a efficient combustion mode but roughness combustion under high load limits its application. This test analyzed the combustion parameters variation coefficient and quantified the correlation between combustion parameters with spark ignition ratio under high load SACI mode for engine fueled with methanol and gasoline, further studied the potential of i-EGR combining air dilution on improving combustion performance. Results showed that fueled with methanol can reduce in-cylinder pressure and pressure rise rate, and relieve the combustion roughness. However, compared with gasoline engine, the combustion parameters was more sensitive to ignition timing and i-EGR rate, especially for combustion phase parameters like ignition delay, combustion center and so on. Introducing small amount of high-temperature exhaust gas into cylinder will induce rougher combustion, but cylinder pressure significantly reduced and combustion phase parameters fluctuated with i-EGR rate increasing. Under high i-EGR rate, methanol as an oxygenated fuel was more beneficial to maintain stable combustion. I-EGR coupling air dilution can significantly improve the economic performance under high load SACI mode, fuel economy improvements of up to about 17.4% and 19% compared to the origin point when fueled with gasoline and methanol. EGR combining air dilution can simultaneously improve BSNOX, BSTHC, and BSCO emissions.

Natural gas-fueled HCCI engine performance and emission analysis and comparison with SI and spark-assisted operations

ABSTRACT The homogeneous charge compression ignition (HCCI) engine is a promising technology in terms of both soot and NOx emission. Natural gas (NG) is advantageous especially for HCCI engines with its single stage combustion, low C/H ratio, and high octane number. Since the main challenge of HCCI technology is stability and transient operations, using HCCI for constant speed operations may be advantageous. In this study, a CI diesel engine, which is used as a generator at constant speed, was modified and converted into an NG-fuelled, SI engine. Then, the engine was supplied with NG for SI, HCCI, and spark-assisted HCCI experiments. Spark-assisted operations were executed by using 3, 5, and 7 degree ignition advance values to assist HCCI combustion. In-cylinder pressure variations, exhaust temperature, specific fuel consumption, and emission values were investigated for comparison of different strategies. Experimental results showed that using the HCCI strategy and retardation of ignition advance of spark-assisted HCCI operations reduced maximum pressure. Therefore, these strategies improved NOx emissions, while HC emissions were slightly increased. The spark-assisted HCCI strategy improves the stability of operation while increasing CO emission. The specific fuel consumption value of HCCI was slightly higher than that of SI operation, while it was lower than spark-assisted strategies.

A full-scale CFD model of scavenge air inlet temperature on two-stroke marine diesel engine combustion and exhaust emission characteristics

Most ships in the maritime transport sector are equipped with large two-stroke marine diesel engines in their propulsion systems. Therefore, ensuring stable and long-term operation of these engines is crucial to maintaining freight transportation. The design of the ship's machinery, particularly the diesel engine, is a crucial step in achieving this goal. Computational Fluid Dynamics (CFD) tools can be used to achieve this goal. This article presents a full-scale CFD study on the effect of different scavenge air inlet temperatures (300, 312, 330 and 340 K) on the combustion process and generation of exhaust emissions in a two-stroke marine diesel engine using ANSYS Forte software. Regarding the cylinder pressure, the presented model agrees well with experimental data. The maximum cylinder pressure decreases as the scavenge air inlet temperature increases, whereas the maximum cylinder temperature increases as the scavenge air inlet temperature increases. The maximum NOX, CO and UHC emission values are calculated to be 2256.5, 20375.8 and 3743.9 ppm, respectively, at a scavenge air inlet temperature of 340 K. Due to the higher combustion temperature caused by the increasing scavenge air inlet temperature, it is observed that the exhaust emission levels increase.

Experimental study on emissions and particulate characteristics of diesel engine fueled with plastic waste oil, acetone-butanol-ethanol and diesel blends

Plastic waste poses a significant environmental challenge due to its non-biodegradable nature and accumulation in landfills. Converting plastic waste into usable fuel could offer a promising solution for mitigating these issues while addressing the emission-related challenges of diesel engines. This study investigates the impact of plastic waste oil (WPO) obtained through pretreatment and catalytic pyrolysis, blended with acetone-butanol-ethanol (ABE) and diesel fuel, on diesel engine. The aim was to evaluate how these blends affect gaseous emissions, organic compounds, and particle-bound carbon, focusing on their potential to reduce harmful pollutants compared to pure diesel fuel. The results indicated that the ABE5W15D blend significantly reduced smoke and CO emissions by 35.7 % and 17.43 %, respectively, with a slight decrease in HC emissions. However, the ABE20W blend showed elevated NOx levels due to higher ignition delay and increased cylinder pressure. Compared to pure diesel (D100), ABE10W10D and ABE5W15D blends reduced total polycyclic aromatic hydrocarbons (PAHs) emissions by 26.8 % and 37.4 %, respectively. Naphthalene was the dominant PAH, remarkably increasing with W20D use, while longer-chain alkanes associated with lubricant oil had higher W20D emissions. The ABE5W15D blend notably reduced organic carbon (OC) emissions by approximately 38.26 % compared to D100. ABE20D exhibited lower elemental carbon (EC) emissions than D100, although it had higher EC than OC. The W20D blend resulted in larger particle diameters, whereas ABE10W10D showed lower particle counts in the 7–15 nm range. In conclusion, blending plastic waste oil with ABE and diesel fuel can effectively mitigate certain pollutants, depending on the blend composition.

An experimental study of knock analysis of HCNG fueled SI engine by different methods and prediction of knock intensity by particle swarm optimization-support vector machine

Hydrogen and its careers have a lot of potential in transportation industry due to lesser emissions and better performance. Performance of hydrogen enriched compressed natural gas (HCNG) fueled engine is limited by knock. The purpose of this study is to evaluate and predict knock at different operating conditions by varying (0 %–40 %) hydrogen amount in HCNG, by varying (25 %–100 %) load on engine and by varying (700 rpm–1700 rpm) speed of engine. Knock is evaluated by knock ratio, knock intensity, exhaust temperature and in-cylinder heat transfer rate. Quasi-dimensional combustion model (QDCM) MATLAB program is used to calculate in-cylinder pressure theoretically. By increasing (0 %–40 %) hydrogen in HCNG 32.7 %, 7.6 %, 33.5 %, 21.5 % & 6.4 % increment observed in, in-cylinder pressure, knock intensity, knock ratio, in-cylinder heat transfer rate and exhaust temperature respectively. By increasing (25 %–100 %) load on engine 75.8 %, 69.8 %, 88.2 %, 77.8 % & 46.7 % increment observed in, in-cylinder pressure, knock intensity, knock ratio, in-cylinder heat transfer rate & exhaust temperature respectively. By increasing speed (1100–1700) rpm of engine aforementioned parameters decreases by 12.19 %, 38.9 %, 36.06 %, 47.2 % & 14.1 % respectively. Knock intensity is predicted by particle swarm optimization-support vector machine (PSO-SVM) algorithm effectively. To minimize the prediction error, 31 combination of different (1–5) inputs applied to predict knock intensity and found combination of 5 input variable is 67.2 % & 71.9 % more accurate than 1 input variable in-terms of mean squared error and mean absolute error respectively. Findings of this study can be used to train electronic control unit of engine and in the development of HCNG fueled engine.