Nominal Working Research Articles

Prediction of composite pressure vessels’ burst strength through machine learning

In Hydrogen Fuel Cell Electric Vehicles, hydrogen is stored as compressed gas in tanks made from carbon fiber composite. Tanks are designed to withstand 2.25 times the nominal working pressure. If low variability in tank strength can be demonstrated, this margin of safety could be reduced. This requires accurate prediction of the strength of the vessel and quantification of its uncertainty. In this work, several composite pressure vessels are manufactured using filament winding, and the parameters that control the winding and curing recorded as time signals. Process parameters include fiber tension, winding speed, liner pressure, fiber volume fraction, winding time and curing pressure. The vessels are tested for burst pressure. Several configurations are defined, where each manufacturing parameter is changed. The recorded manufacturing data are fed to machine learning(ML) algorithms and trained to predict the vessel’s burst pressure. These ML algorithms include neural networks, Gaussian process regression GPR, Kernel Principal Component Analysis-Lasso (kPCA-Lasso), and an Ensemble regressor. The KPCA-Lasso and GPR models show good correlation. The Ensemble regressor yields better results by combining the KPCA-Lasso and GPR models. The study demonstrates the potential of ML algorithms in predicting the burst pressure of carbon fiber vessels from the monitored manufacturing data.

JWST/NIRCam 4–5 μm Imaging of the Giant Planet AF Lep b

With a dynamical mass of 3 M Jup, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NIRCam imaging of AF Lep b. Across two epochs, we detect AF Lep b in F444W (4.4 μm) with signal-to-noise ratios of 9.6 and 8.7, respectively. At the planet’s separation of 320 mas during the observations, the coronagraphic throughput is ≈7%, demonstrating that NIRCam’s excellent sensitivity persists down to small separations. The F444W photometry of AF Lep b affirms the presence of disequilibrium carbon chemistry and enhanced atmospheric metallicity. These observations also place deep limits on wider-separation planets in the system, ruling out 1.1 M Jup planets beyond 15.6 au (0.″58), 1.1 M Sat planets beyond 27 au (1″), and 2.8 M Nep planets beyond 67 au (2.″5). We also present new Keck/NIRC2 L′ imaging of AF Lep b; combining this with the two epochs of F444W photometry and previous Keck L′ photometry provides limits on the long-term 3–5 μm variability of AF Lep b on timescales of months to years. AF Lep b is the closest-separation planet imaged with JWST to date, demonstrating that planets can be recovered well inside the nominal (50% throughput) NIRCam coronagraph inner working angle.

Phase-cancellation of velocity oscillations in a flow duct using a slow-sound metamaterial

Self-sustained acoustic oscillations in industrial systems with mean flow can cause unwanted vibrations or noise pollution. Acoustic metamaterials can be engineered and integrated in such systems to prevent these limit cycles. In this study, an acoustic metamaterial is proposed for decreasing the acoustic admittance at the outlet of a contraction in a pipe. It can reduce velocity oscillations by more than 50%, without requiring an enlargement of the pipe or increasing the static resistance to the mean flow significantly. The acoustic metamaterial consists of an array of slow-sound and regular channels, which form a contraction in a pipe. The slow-sound effect shifts the resonances of the respective slow-sound channels. For the frequency of interest, the velocity oscillations of these two types of channels are out of phase, which reduces the spatially averaged velocity oscillations at the outlet of the contraction and therefore decreases its acoustic admittance. The effect is demonstrated experimentally, using impedance measurements and particle image velocimetry. A key achievement of this work is the demonstration of a device that is nearly lossless for the mean (steady) flow, i.e. having a low pressure drop, while being very stiff for the acoustic (oscillating) flow at its nominal working frequency, i.e. low admittance, which was so far a difficult challenge to address.

Strong–strong simulations of combined beam–beam and wakefield effects in the Electron–Ion-Collider

Collective wakefield and beam–beam effects play an important role in accelerator design and operation. These effects can cause beam instability, emittance growth, and luminosity degradation, and warrant careful study during accelerator design. In this paper, we studied the combined wakefield and beam–beam effects in an Electron Ion Collider design using strong–strong simulations. The simulation results show that the nonlinear beam–beam effects help suppress wakefield driven instability in the nominal working tune regime. In other tune regimes, the coherent beam–beam modes interact with the wakefields and cause a beam instability. The simulation results also show the importance of maintaining nominal crab cavity voltage. If the crab cavity voltage drops significantly the beam can become unstable.

A structural mechanics analysis on a Type IV hydrogen storage tank during refueling and discharging

High-pressure hydrogen gas, as a power generation fuel widely used in transportation, has significantly contributed to the development of hydrogen fuel cell electric vehicles. However, obvious temperature rise and drop during fast refueling and discharging cause serious safety risk to the structural stability of on-board hydrogen storage tank. The American Society of Automotive Engineers SAE J2601 and the international standard ISO 15869 strictly stipulate that the operation temperature range of hydrogen storage tank varies from −40 °C to 85 °C. In this study, a finite element mechanics model was constructed using ACP and Static Mechanical software to better understand the deformation, stress, strain, and failure modes experienced by a Type IV tank during charging and discharging. Detailed parameters such as ply angle, ply thickness, mesh generation, and boundary conditions, were extensively elucidated. The results indicate that the high temperature and pressure generated during fast fueling of the storage tanks are less likely to cause yield failure of the inner, outer layers and plug, but the stress concentration caused by low temperature and high pressure may lead to the fracture rupture of internal polyethylene materials. Aluminum alloy plug, serving as sealing devices for the tank, are most susceptible to yielding failure under coupled conditions. The mechanical load reaching the yield stress of the plug is approximately 85 MPa with the nominal working temperature of 85 °C. Additionally, the maximum stress on the outer layer can be reduced by adjusting the circumferential layer direction from 90° to 70° or by optimizing the orientation of the maximum stress layer increasing it by 110°. The present study can offer new insights into the dynamic loading behavior of the Type IV tanks during fast charging and discharging, and may provide technical references for optimization design of the tank structures.

An Extensive Review of MR Sensors with Design and Characteristic Evaluation of Three-layered TMR Sensor

Abstract: The reliability and efficacy of sensor-based automated systems have improved due to the proliferation of electric vehicles, renewable sources, and integrated systems in power industries extensively. This has been accomplished by increasing the power density and decreasing the volume of the system. Background: Mathematical estimation and comparative analysis of the physical factors result in massive usage of operational matrices measured using sensors. Magnetic field sensors, used in industries and biomedical applications, have a high level of precision in the evaluation of measurements. In order to extract the measured parameters such as sensitivity, accuracy, operating cost, the linear range of operation, and power utilisation, these sensors adhere to the physical constraints during their nominal working conditions. The characteristics of the aforementioned sensors are enumerated in detail in this article. Objective: This objective is highly focused on providing a comprehensive overview of classification and the properties of Hall-Effect, anisotropic magnetoresistive (AMR), giant magnetoresistive (GMR), and tunnelling magnetoresistive (TMR) sensors. The dissertation on its properties concludes that TMR is more reliable and sensitive in variable operating conditions. Methods: The methods for selecting the sensors for an application are confined to voltage fluctuations and sensitivity. A three-layered TMR sensor with two magnetic layers and an insulator in between is proposed as a significant advancement compared to the literature. The micromagnetic simulation is carried out at room temperature for a three-layered TMR made up of neodymium alloy, magnesium oxide, and cobalt platinum alloy. Conclusion: Based on the studies executed, it is determined that TMR is more sensitive than both conventional and MR sensors. The proposed schematic claims that the higher free layer thickness offers maximum sensitivity with 77% negative magnetoresistance. The reduced coercivity of 1.9Oe is achieved in this combination at a specified temperature range.

Release of high-pressure hydrogen from type III tank in a fire scenario: Analysis and prediction of jet flame length and thermal response characteristics

In this paper, the thermal response and jet flame behaviour of a typical type III high-pressure hydrogen storage tank with nominal working pressure (NWP) and volume of 70 MPa and 48 L were analysed at fire scenarios. The tank was discharged at a critical internal pressure 77.4 MPa, which was ca. 110 % of NWP. The pressure drop rates of type III tanks were greater than 1 MPa/s during the initial 15 s after venting. The length and width of jet flame were 4.93 and 1.65 m at the critical moment, which fluctuated downward over time. A thermokinetic model was employed to predict the variation of hydrogen gas state parameters and the maximum length of jet flame. The calculation results indicated that the maximum flame length of hydrogen released from a valve of 2 mm was around 2–6.5 m under a pressure range of 10–80 MPa. The error between the predicted results and the experimental values was less than 5 %. It was found that the flame length was enlarged by an increase of aperture. The length of flame increased by 6 m after the aperture changed from 2 to 5.08 mm at the equivalent pressure.

Analyzing Small-Signal Stability in a Multi-Source Single-Area Power System with a Load-Frequency Controller Coordinated with a Photovoltaic System

The frequency deviation from the nominal working frequency in power systems is a consequence of the imbalance between total electrical loads and the aggregate power supplied by production units. The sensitivity of energy system frequency to both minor and major load variations underscore the need for effective frequency load control mechanisms. In this paper, frequency load control in single-area power system with multi-source energy is analysed and simulated. Also, the effect of the photovoltaic system on the frequency deviation changes in the energy system is shown. In the single area energy system, the dynamics of thermal turbine with reheat, thermal turbine without reheat and hydro turbine are considered. The simulation results using Simulink/Matlab and model analysis using eigenvalue analysis show the dynamic behaviour of the power system in response to changes in the load.

Analysis of the Hydrogen‐Filling Process of Fixed Station and Skid Station Based on Different Working Conditions

Hydrogen energy is recognized as the most potential renewable energy in the 21st century due to the rising depletion of fossil fuels. Hydrogen refilling stations, as the infrastructure of hydrogen energy, are one of the key components of the entire hydrogen energy industry chain. Analyzing the filling process of hydrogen‐refueling stations (HRS) helps to promote the construction of HRSs. Thus, it promotes the construction of a clean, low‐carbon, safe, and efficient energy system and the high‐quality development of the hydrogen energy industry. In this article, gas cylinders with nominal working pressures of 35 and 70 MPa are filled using three different HRSs, such as single‐stage fixed station, three‐stage fixed station, and skid station. The filling end temperature, filling energy consumption, filling rate, and filling time during the filling process are compared and analyzed. In the results, it is shown that skid station has the advantages of lower filling end temperature and less energy consumption. Thus, in terms of reducing energy loss, the skid‐mounted HRSs can be promoted.

Rational Design of Dendritic Phase‐Pure Tin Antimonide Intermetallic Film‐Based Negatrodes for Commercially‐Viable Flexible Sodium‐Ion Pouch Cell Battery

AbstractExploiting the ability to directly deposit larger‐sized, flexible, alloying‐type sodium‐ion battery electrodes without the need of additional inactive components and processing steps is a strategic way to achieve higher gravimetric capacities which will be suitable for commercial‐level sodium‐ion (SIB) pouch cell manufacturing. In this regard, a simple, template‐free electroplating protocol is reported for designing phase‐pure tin antimonide (TA)‐based negatrode. An optimum control over the potentiostatic electroplating parameters allows the preferential formation of dendritic nanostructures over an electroplated foam‐based current collector. The prepared negatrode and Mn‐based Prussian blue analog positrode in full coin cell format deliver an average nominal working voltage of 3.0 V with a discharge energy density of 342 Wh kg−1. In single‐layer full pouch cell format, an 8.01 mAh capacity (89.89 mAh g−1, 593.3 µAh cm−2) is achieved at an undeformed state and 97.12% capacity is retained at 180° bend condition. In multi‐layer full pouch cell format, a 35.86 mAh capacity (80.58 mAh g−1, 531.2 µAh cm−2) is achieved with 62.77% capacity retention after 200 cycles (0.125 C). The results of this work showcase how a simple, template free, aqueous electrolyte based electroplating protocol can be developed for the direct fabrication of large‐sized, flexible, alloying‐type negatrodes for commercial SIB pouch cells.

Investigation of Hydrogen Transport Properties through the Liner Material of 70 MPa Type IV Composite Overwrapped Pressure Vessels

In zero-emission solutions for the hydrogen supply chain, high-pressure hydrogen storage in Type IV composite overwrapped pressure vessels (COPVs) is crucial for being safe and secure for a variety of stationary and transport applications. These COPVs consist of a polymeric liner material that works as a barrier for the stored hydrogen, while the carbon fiber-based composite provides the strength to hold the high-pressure hydrogen (of nominal working pressure more than 70 MPa to achieve the competitive driving range). Several experimental studies and simulation work have been performed on the viability of various polymers as low-permeability materials under low-pressure conditions. However, because of their proprietary nature and commercialized research, the characteristics of hydrogen permeation through polymers and their behavior at high pressure are still readily available in the literature. It is a major concern and the most crucial component of Type IV COPVs that these polymeric liners hold high pressure and maintain the necessary density of hydrogen (state of charge) toward operational requirements and safety concerns related to the cause of failures due to permeation (such as blistering, buckling, cracking, and so on). This paper investigates the role of polymeric liners on hydrogen permeation behavior using finite element modeling. For this, a UMATHT subroutine is developed within the Abaqus software to implement a new hydrogen permeation transport model with extended governing equations. Through the simulations and material modeling, the role of hydrogen transport properties (permeability, diffusivity, and solubility), structural characteristics (crystallinity, free volume, thickness) of plastic liners, and the role of operational parameters (concentration, pressure) are combined to validate the model from the experimental data in the literature to estimate the effective thickness required to maintain the permeation limit of the polymeric liner of 70 MPa Type IV COPVs.

Strength and Failure Analysis of Fiber-Wound Composite Gas Cylinder via Numerical Simulation.

Based on the classical grid theory and related regulations, a structure model of a fiber-wound composite gas cylinder was designed in this paper. Based on the design results, a finite element model of a fully wound composite cylinder of an aluminum alloy inner liner with a working pressure of 35 MPa was established based on the ABAQUS software, and its stress distribution under working pressure and minimum burst pressure was analyzed. According to engineering experience, the pressure tolerance of composite cylinders can be improved by proper autofrettage pressure before working pressure, so the influence of autofrettage pressure was analyzed in this paper. The optimum autofrettage pressure was selected by setting the autofrettage gradient, and damage analysis was carried out on the cylinder with nominal working pressure of 35 MPa based on the Hashin failure criterion. The results show the initial damage sequence: matrix stretching occurs before the fiber stretching, and the damage generally starts from the spiral-wound layer. The tensile damage first appears in the transition section between the head and the barrel body, and the damage of the spiral-wound layer develops from the inner layer of the wound layer to the outer layer, while the damage of the circumferentially wound layer develops from the outer layer to the inner layer.

Proposal of a new method for the characterization and operational air leakages assessment in HVAC systems

Reducing air leakages in HVAC systems is potentially one of the actions with the best potential for energy savings in the residential sector. The assessing of air leakages in HVAC systems is currently addressed in two ways: i) the traditional DALT (Ducts Air Leakage Tests) to characterize and compare ductwork and ii) the ASHRAE 215:2018 standard method to measure leakage at nominal working conditions. In this paper an innovative experimental method for assessing air leakages in HVAC systems at operative conditions is proposed. The method is based on flow rate measurements at different pressures and performed with closed terminal dampers. The so called “Shut-Off Method” has been then experimentally validated in a real plant showing good agreement with the ASHRAE 215 procedure. Finally, on the basis of the Shut-Off model application, the leakage coefficient used by the standard DALT classification procedure was calculated, showing leakage performance 2,3 times worse than the Eurovent Class A requirements.

Explosion free in fire self-venting (TPRD-less) Type IV tanks: Validation under extreme impinging 70 MPa hydrogen jet fire conditions

High-pressure hydrogen jet fire from a storage tank impinging another tank located nearby is a worst-case incident scenario. This could result in storage vessel rupture with catastrophic consequences implying life and property loss. The concept of microleaks-no-burst (μLNB) performance of hydrogen storage tanks of Type IV is explained. In this study, the breakthrough safety technology of explosion free in fire self-venting (TPRD-less) tank with nominal working pressure (NWP) of 70 MPa is validated again st the most extreme fire conditions of an impinging hydrogen jet from 70 MPa tank. The results of the successful performance of self-venting tank in momentum-dominated hydrogen impinging jet fire are analysed. This work expands further the experimental validation domain of the explosion free in fire self-venting tanks to scenario of impinging fire of the highest applied intensity of HRR/A = 19.5 MW/m2.

ANALYSIS OF STRUCTURAL SOLUTIONS FOR RADIATORS IN BUILDINGS

In the following article emphasizes the analysis of technical and economic criteria for radiators, that will help you make the right choice of radiator type. Different solutions for heating flats are presented, the focus is on water-fed radiator solutions. After detailed analysis, the evaluation criteria are selected: indicators of the unit heat output of a radiator related to the mass, volume and length of the radiator QM, QV, QL. Radiator types, nominal working parameters, evaluations criteria and techno-economic analysis of structural solutions for radiators on the example of a residential building are presented.

Dynamic Modeling and Operation of a Green Hydrogen Fueling Station for Heavy-Duty Fuel Cell Vehicles

Hydrogen fuel cell electric vehicles (FCEVs) have increased driving ranges and faster refueling times than battery electric vehicles (BEVs). The driving range of FCEVs can be increased by increasing the size, quantity or operating pressure of on-board hydrogen storage tanks at a lower weight and cost than increasing the size or number of Li-ion battery packs in BEVs. Ffast-refueling leads to less waiting time at the fueling station for high-utilization commercial vehicles. As a result, fuel cell system heavy-duty vehicles (HDV) are attracting more attention [1]. Currently, the lack of a hydrogen refueling infrastructure is limiting FCEV adoption. Since the driving routes of HDV trucks are more predictable, a small number of strategically located fueling stations could service pre-planned truck driving routes [2]. While hydrogen refueling protocols and fueling stations for light-duty vehicles (LDV) have been extensively studied [3,4,5], HDV trucks have different refueling protocols and operating conditions (e.g. mass holdup, pressure, refueling rate). To our knowledge, little work has been done on modeling hydrogen fueling stations for HDV trucks applications. With this motivation, a dynamic model of a truck stop coupled with green hydrogen production has been developed for fleet HDV trucks. At the truck stop, green hydrogen is produced from water electrolysis using solar photovoltaics (PV). Electrochemical hydrogen compression (EHC) is implemented for high-pressure hydrogen storage and dispensing. The fluctuations from solar PV and truck hydrogen demand are actively managed by installation of a spherical hydrogen storage vessel. The feasibility and flexibility of a truck stop using 100% renewable electricity and hydrogen will be discussed.A high-fidelity dynamic model of a Proton Exchange Membrane (PEM) electrolyzer is developed for hydrogen production from PV electricity. A PEM electrochemical hydrogen compressor model is developed for gas pressurization with consideration of EHC temperature and water management. The green hydrogen is stored in a large spherical storage vessel to decouple the different PV power loads and HDV trucks hydrogen refueling demands. A modular system for HDV trucks refueling (nominal working pressure of 35 MPa) is designed and modeled with parallel multi-stage hydrogen compression and cascaded storage tanks. It was found that single modular system for FCEV refueling shows a service gap during hydrogen cascaded storage tank refilling, but a multiple modular structure can be easily expanded and provide uninterrupted hydrogen for FCEV refueling.The different hydrogen production and dispensing scenarios are implemented depending on the seasonal solar supply and varied HDV trucks demands. Hydrogen compression using mechanical compressor and electrochemical compressor are compared. The truck stop operation strategies are proposed based on the integrated process systems analysis of solar penetrations, hydrogen production and compression, and HDV trucks demand. The feasibility and flexibility of truck stop fueled by solar energy provide an insight for the transition to Net Zero Emission Transportation.[1] Cullen, D.A., Neyerlin, K.C., Ahluwalia, R.K., Mukundan, R., More, K.L., Borup, R.L., Weber, A.Z., Myers, D.J. and Kusoglu, A. (2021). New roads and challenges for fuel cells in heavy-duty transportation. Nature energy, 6(5), 462-474.[2] Cano, Z. P., Banham, D., Ye, S., Hintennach, A., Lu, J., Fowler, M., & Chen, Z. (2018). Batteries and fuel cells for emerging electric vehicle markets. Nature Energy, 3(4), 279-289.[3] Xiao, L., Chen, J., Wu, Y., Zhang, W., Ye, J., Shao, S., & Xie, J. (2021). Effects of pressure levels in three-cascade storage system on the overall energy consumption in the hydrogen refueling station. International Journal of Hydrogen Energy, 46(61), 31334-31345.[4] Rothuizen, E., Mérida, W., Rokni, M., & Wistoft-Ibsen, M. (2013). Optimization of hydrogen vehicle refueling via dynamic simulation. International journal of hydrogen energy, 38(11), 4221-4231.[5] Rothuizen, E., & Rokni, M. (2014). Optimization of the overall energy consumption in cascade fueling stations for hydrogen vehicles. International journal of hydrogen energy, 39(1), 582-592.

Explosion free in fire self-venting (TPRD-less) composite tanks: Performance during fire intervention

This paper describes the performance of explosion free in fire self-venting (TPRD-less) composite tanks in fires of realistic specific heat release rate (HRR/A), i.e., total fire HRR over the source area, A, of HRR/A = 1 MW/m2, during fire intervention. This breakthrough safety technology does not require thermally activated pressure relief devices (TPRD). It provides microleaks-no-burst (μLNB) performance of hydrogen storage tanks in fire. The study investigated two fire intervention strategies, i.e., removal of vehicle with μLNB tank from the fire, and extinction of fire by water. One carbon-carbon and one carbon-basalt double-composite wall tanks were assessed in the removal from fire scenario. Four carbon-basalt prototypes were studied in fire extinction scenarios. All six prototypes of 7.5 L and nominal working pressure of 70 MPa have demonstrated safe release of hydrogen through microchannels of the wall after the liner melting. The μLNB technology allows to apply standard intervention strategies and tactics.

An adaptive constrained clustering approach for real-time fault detection of industrial systems

Thanks to the pervasive deployment of sensors in Industry 4.0, data-driven methods are recently playing an important role in the fault diagnosis and prognosis of industrial systems. In this paper, a novel Adaptive Constrained Clustering algorithm is defined to support real-time fault detection of an industrial machine, by clustering the incoming monitoring data into two clusters over time, representing the nominal and non-nominal work conditions, respectively. To this aim, the proposed algorithm relies on a two-stage procedure: micro-clustering and constrained macro-clustering. The former stage is responsible for grouping the batches of work-cycle data into micro-clusters, while the data stream continuously arrives from the data acquisition system. Then, after condensing the micro-clusters into vectors of cluster features, and leveraging on additional knowledge on the nominal and non-nominal working conditions (i.e., constraints on some samples), the second stage aims at offline grouping the micro-clusters features into macro-clusters. Experimental results on a real-world industrial case study show that the proposed real time framework achieves the same results of offline baseline methods (e.g., Constrained K-means) with a higher responsiveness and processing speed; in comparison to stream baseline methods (e.g., Stream K-means), the proposed approach obtains more accurate and easily interpretable results.

Breakthrough safety technology of explosion free in fire self-venting (TPRD-less) tanks: The concept and validation of the microleaks-no-burst technology for carbon-carbon and carbon-glass double-composite wall hydrogen storage systems

The paper describes the breakthrough microleaks-no-burst (μLNB) safety technology of explosion free in fire self-venting hydrogen tanks that do not require thermally-activate pressure relief devices (TPRD). The technology implies melting of the hydrogen-tight liner before hydrogen-leaky double-composite wall loses its load-bearing ability. Hydrogen then flows through the wall's microchannels and either burns in microflames on its own or together with resin. The experimental validation of the technology is presented for 7 prototypes with the nominal working pressure of 70 MPa made of carbon-carbon or carbon-glass composites. The prototypes are fire tested at the specific heat release rate HRR/A = 1 MW/m2 characteristic for gasoline/diesel spill fires. The μLNB technology eliminates catastrophic consequences of tank rupture in fire: blast waves, fireballs, and projectiles. The technology limits hydrogen accumulation in naturally ventilated enclosures. It reduces the risk of hydrogen-powered vehicles to an acceptable level below that for fossil fuel automobiles, including underground parking and tunnels. It provides an unprecedented level of life safety and property protection.

In-Cylinder Pressure Estimation from Rotational Speed Measurements via Extended Kalman Filter.

Real-time estimation of the in-cylinder pressure of combustion engines is crucial to detect failures and improve the performance of the engine control system. A new estimation scheme is proposed based on the Extended Kalman Filter, which exploits measurements of the engine rotational speed provided by a standard phonic wheel sensor. The main novelty lies in a parameterization of the combustion pressure, which is generated by averaging experimental data collected in different operating points. The proposed approach is validated on real data from a turbocharged compression ignition engine, including both nominal and off-nominal working conditions. The experimental results show that the proposed technique accurately reconstructs the pressure profile, featuring a fit performance index exceeding 90% most of the time. Moreover, it can track changes in the engine operating conditions as well as detect the presence of cylinder-to-cylinder variations.