bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Surface Coatings on the Tribological Properties of Sliding Contacts
Authors: Sharma Vipin Kumar , Joshi Sumit , Mittal Rajat , Kaushik Ishaan , Vashisth Garvit , Goel Kunal , Gupta Tarun
Published: April 2023

The present work discusses the effects of Electrolytically deposited chromium coating on the Tribological behaviour of piston ring material. The frictional behaviours were evaluated using the linear reciprocating Tribometer under varying conditions of load and temperature. Test temperatures of 25, 50, and 100 degrees Celsius and loads of 20, 30, and 40N were applied during the tests to obtain the wear response of the coating under conditions similar to real piston cylinder/ring friction conditions. Tests were carried out with a constant sliding speed of 0.1 m/s. Optical micrographs and scanning electron microscope were used to analyze the nature of wear. It has been found that for lubricated or non-lubricated and coated or uncoated specimens, on increasing load, wear and surface roughness both increased for pins and plates. For dry conditions and a fixed load of 30N, wear of coated pins is found to be increasing with temperature from 25॰C to 100॰C, but plate wear shows a fully opposite variation in wear with increasing temperature thus wear decreased. Therefore, a substantial resistance to wear has been achieved by the hard chromium coating of pins.
Enhanced Combustion by Photo Ignition of Carbon Nanotubes in a Constant Volume Chamber
Authors: Bjorgen Karl Oskar Pires , Saanum Inge , Bratsberg Stian , Jørgensen Patrick , Lovas Terese , Emberson David
Published: April 2023

Using ammonia as fuel in retrofitted large marine vessels or heavy-duty vehicles has the potential to reduce CO2 emissions. However, ammonia is hard to burn in an internal combustion engine (ICE) due to its poor combustion properties, i.e. having high autoignition temperatures and low flame speeds. This results in the need for a highly reactive secondary fuel or an improved ignition system for achieving complete and stable combustion. This study investigates a radical technology for the ignition of a fuel-air mixture using carbon nanotubes. The technology consists of injecting a mixture of multi-walled carbon nanotubes and ferrocene (CNT-Fe) into a fuel-air mixture and subjecting the particles to a bright flash of light. Due to the photochemical properties of CNT-Fe particles, the absorbed light initiates ignition. The burning particles thereby ignite the gas mixture at multiple points in the chamber, resulting in a flame front propagating faster compared to when using conventional methods like spark plugs. This study investigates the concept in a constant volume chamber filled with mixtures of methane and air, where the CNT-Fe is dispersed inside the chamber and ignited by an externally located xenon flash tube through a quartz window. The aim of the study was to provide a proof of concept, showing that an external light source can initiate combustion in a chamber by CNT-Fe, potentially demonstrating that the technology can be transferred to an engine. Different mixtures of methane/air and chamber pressures were tested. The results show that photo ignition of methane/air is achieved for mixtures with equivalence ratios of 0.65-0.9, whilst for spark ignition the equivalence ratio range was 0.7-1.4. A qualitative assessment of the flame spread is made through optical measurements of the flame front, showing that dispersed CNT-Fe achieves faster burn rates.
Investigation of Compressor Deposit in Turbocharger for Gasoline Engines (Part 2: Practical Application to Turbocharger)
Authors: Ura Haruto , Kuma Hiroshi , Hirano Satoshi , Ishizaki Noriya
Published: April 2023

Contribution to carbon neutrality is one of the most important challenges for the automotive industry. Though CO2 emission has been reduced through electrification, internal combustion engines equipped in vehicles such as Hybrid Electric Vehicle (HEV) and Plug-in Hybrid Electric Vehicle (PHEV) are still necessary for the foreseeable future, and continuous efforts to improve fuel economy are demanded. To improve powertrain thermal efficiency, direct-injection turbocharged gasoline engines have been widely utilized in recent years. Super lean-burn combustion engine has been being researched as the next generation of turbocharged gasoline engines. It is known that an increase of the boost pressure causes deposit formation, which decrease the turbocharger efficiency, in the turbocharger compressor housing. To avoid the efficiency loss due to deposit, air temperature at compressor outlet has to be limited low. In this paper, the methodology was constructed to predict compressor efficiency loss, based on the mechanism of turbocharger deposit formation in gasoline engines.

Test procedure to reproduce compressor deposit in turbocharger unit test equipment was developed. The correlation between the temperature of compressor housing inner surface and the rate of compressor efficiency loss was clarified. In addition, the correlation between the location where deposit was formed and the compressor efficiency loss was also investigated. As opposed to steady-state operation such as engine dyno tests, vehicle operations in actual markets are transient, and the boost pressure of turbocharger and its outlet air temperature can vary widely. Due to the thermal capacity of compressor housing, the temperature of housing changes after the outlet air temperature changes with certain time delay. The temperature model considering this delay has been developed and enabled to estimate the deposit formation, turbocharger efficiency loss and engine performance deterioration in transient conditions.
Data-driven Approach for Condition Assessment of a Diesel Engine Powered with Various Biodiesels
Authors: Zhang Ming , Sharma Vikas , Jia Yu , Hossain Abul Kalam , Xu Yuchun
Published: April 2023

In recent years, various biodiesels have been developed to decrease pollutant emissions from compression ignition engine. However, the current research focuses on reducing the pollutant components without considering the mechanical vibration that occurred due to the changes in fuel properties such as viscosity, calorific values, density, and bulk modulus. It is important to explore the relationships between fuel properties and engine vibration. Mechanical vibration could cause power loss and affect the lifetime of the engine. In this investigation, a lister-pitter 3-cylinder diesel engine was used to analyse the mechanical vibration of three different fuels including diesel, waste cooking oil biodiesel (WCOB), and lamb fat biodiesel (LFB). The high-frequency vibration sensors were mounted on the cylinder head to monitor and assess the vibration performance. The vibration data were collected under various operating conditions including varying engine speed from 1500 to 2000 rpm and varying engine loads ranging from 20% to 100%. Three practical assessment features of vibration signals were investigated to evaluate the vibration characteristics. The experimental results clearly demonstrate the relative relations between vibration, and fuel properties of the tested fuels, used in the diesel engine. Compared with fossil diesel fuel, the total vibration level decreased by 17% and 23% for WCOB and LFB fuels, respectively. The engine performance powered with LFB and WCOB are better than diesel’s effect on both vibration and friction power (FP) perspective. Superior lubricity and viscosity of WCOB and LFB is the main reason causing good vibration performance.
Powertrain NVH CAE Predictions with Gasket Consideration
Authors: Singh Aniruddh Pratap , Kumar Vinay , Garg Ankit Kumar
Published: April 2023

NVH predictions have gained importance since last few decades due to increased focus on ride comfort as competitive advantage within cost target. Hence, NVH CAE has become integral part of product development process for early issue identification and solutions. To make NVH simulation robust, continuous improvement is required in existing CAE processes.

In automobile powertrains, components are connected with each other through fasteners. Gaskets are sandwiched at periphery between two mating components, while the components are bolted together with required torque. Gaskets are used to prevent leakage of oil and gases into the atmosphere while operation. NVH CAE modeling practices globally are evolved with considering gaskets as one of the less important modelled components. However, these practices miss to consider its effects considerably on NVH performance.

Scope of this paper is to address the gaps present in the existing powertrain modeling techniques with the introduction of gasket. First the impact of gasket inclusion is studied at the experimental level. Then modified CAE modeling process is proposed with modal correlations perspective.
Development of Automated Driveability Rating System
Authors: Gankov Stanislav , Gunter Garry , Kyler CeCe , Rengarajan Sankar , Rao Sandesh
Published: April 2023

Trained human raters have been used by organizations such as the Coordinating Research Council (CRC) to assess the vehicle driveability performance effect of fuel volatility. CRC conducts workshops to test fuel effects and their impact on vehicle driveability. CRC commissioned Southwest Research Institute (SwRI) to develop a “Trick Car” vehicle that could trigger malfunctions on-demand that mimic driveability events. This vehicle has been used to train novice personnel on the CRC Driveability Procedure E-28-94. While largely effective, even well-trained human raters can be inconsistent with other raters. Further, CRC rater workshop programs used to train and calibrate raters are infrequent, and there are a limited number of available trained raters. The goal of this program was to augment or substitute human raters with an electronic driveability sensing system. The Automated Driveability Rating System (ADRS) was developed for Light Duty (LD) vehicles and can identify and rate fuel-related driveability events including hesitation, stumble, surge, stall, and idle quality at trace, moderate, and heavy severities. The portable system uses sensors such as accelerometers, and interfaces with a vehicle to gather and process an array of information. Overall, ADRS performance ranged from somewhat less accurate to significantly better than trained human raters depending on the event type and severity. For light and moderate vehicle throttle tests, detection of stumble, surge, and hesitation events by the ADRS was close to or better than 90%, while idle quality accuracy was 80%. These results are better when compared to the performance of trained raters. Additional effort in refining the calibration and improving event identification could enhance performance even further, and the system could be applied more broadly in rating ride quality and vehicle behavior.
Design of Rectangular Cross Section Helical Resonator for Noise Attenuation in Air Induction System
Authors: Kumar J Thirumala Sai , Dixit Manish
Published: April 2023

Noise pollution is a prominent environmental hazard faced by the automobile industry. The design of automotive Air Induction Systems (AIS) plays a crucial part in attenuating noise emitted by an engine. In addition to this, sound attenuating devices are connected in series and in parallel to the AIS for effective noise attenuation. This paper presents three-dimensional (3D) acoustic and flow results of one such sound attenuating device, the Helical Resonator (HR), which is attached to the AIS of a 3.6 L engine replacing the existing Helmholtz resonators (HHR). The baseline AIS has four HHRs to attenuate four major engine noise frequencies. In this paper, design parameters were selected to allow the HR to capture at least two of the four frequencies and minimize the cost at space concerns. The analytical four-pole Transfer Matrix Method (TMM) approach is applied to initially calculate Transmission Loss (TL) and arrive at a suitable set of HR design parameters. This allows us to understand the sound attenuation capability of the HR. Fine-tuned design parameters of the HR are implemented in the full AIS using GT-POWER® in the frequency range of 0 to 1000 Hz. Siemens 3D Simcenter® is used to estimate the impact of the HR on noise attenuation for correlation. STAR-CCM+® is used to estimate the amount of pressure drop contributed by the HR. This design can be used for future applications if the additional pressure drop due to HR is within permissible limits.
Development of a Gear Backlash Compensator for Electric Machines in P0-P4 Parallel Hybrid Drivelines
Authors: Capito Vicente , Ketineni Pranay , Midlam-Mohler Shawn
Published: April 2023

Backlash is the movement between the gear teeth that allows them to mate without binding. Backlash can cause large torque fluctuations in vehicle powertrains when the input torque changes direction. These fluctuations cause a jerk and shuddering, which negatively affects drive quality. Input torque frequently changes direction in electric vehicles due to regenerative braking. Limiting zero crossings is an option for better drive quality; however, this leads to decreased vehicle efficiency. Because of this, modulating the torque through the backlash region is preferred, yet, if done poorly, it can result in sluggish torque response.

This paper proposes a torque-shaping algorithm for an electric motor and gear/differential system to reduce backlash in electric vehicles. The control algorithm modulates the commanded torque’s rate of change based on the vehicle speed and zero-crossing torque. The torque change is dynamically de-rated over the backlash region, and the gears are gently re-engaged to transmit the torque. The algorithm considers the variability in electric machine designs and e-gear drives and provides calibration tables to change the base rate. This rate is modulated and filtered before applying to commanded torque in both directions. The initial parameters were calculated using model-in-loop simulations. They are later calibrated in closed course testing with specific tip-in and tip-out conditions at various speeds and accelerator pedal positions.

The algorithm was applied on a modified 2019 Chevrolet Blazer with a P0-P4 parallel hybrid architecture using a GVM210-150 Parker Hannifin motor connected to a BorgWarner single-speed gear unit on the rear axle. The algorithm reduced shudder during tip-in and tip-out torque commands from the driver, which yielded a 70% reduction in jerk while maintaining responsive control of the vehicle. The vehicle was subjected to various customer-focused evaluations as part of the DOE/GM EcoCAR program.
Study on the Effect of Gravity on the Performance of CPVA
Authors: Zhang Yi , Fang Weirong , Wu Guangqiang
Published: April 2023

Most centrifugal pendulum vibration absorber (CPVA) research focuses on the horizontal or vertical plane, ignoring the influence of gravity. However, with the wide application of CPVAs in the automobile industry, some gravity-related problems have been encountered in practice. In this study, employing the second kind of Lagrange equation, the differential equation of motion of a CPVA is established, and the first-order approximate analytical solution is solved using the method of multiple scales. The mathematical relations among the excitation torque amplitude and phase, gravity influence, absorber trajectory shape, absorber position, viscous damping coefficient, and mistuning level parameters are provided for study. Specifically, the second-order responses of four absorbers and two absorbers in a gravity field are studied, and the influence of the change in the torque excitation phase on the response of the absorber is thoroughly analyzed. The grouping phenomenon in four absorber applications is found during the simulation, and a mathematical explanation is provided. The influence of the absorber viscous damping coefficient on the amplitude and the rotor angular velocity is discussed. To maximize the performance of the CPVA, a damping quality factor Q is defined to compare different end stop positions, and a design principle for the end stop is finally determined. From a mathematical point of view, this explains why a CPVA affects the angular acceleration of the rotor, and the influence of the design parameters on the synchronization and stability of the CPVA is discussed. Using the CPVA differential equation of motion considering gravity, a MATLAB Simulink model is created to simulate the influence of the torque excitation phase on CPVA performance. Especially, one set of CPVA is tested on dynamometer and vehicle, and the test results were compared with simulation results.
Development of Rumble Noise Analysis Method for Electric Powertrain
Authors: CHOI JAEHYUK , Ha Tae-Won , Chung Eui Cheol , Jeong Hye Sung , JUNG KUNSOO , Harris Owen , Gale Andy , Harvey Tom , Kim Sungho
Published: April 2023

In electric-powertrains, noise and vibration can be generated by components such as gears and motors. Often a noise phenomenon known as rumble or droning noise can occur due to low shaft order excitation at the spline. In this study, we identified the excitation source for spline induced rumble noise and developed a novel analysis method. First, a detailed spline model, believed to be the key factor for rumble noise, has been developed and verified by comparison with Finite Element Method(FEM) analysis. In order to identify an excitation source, a typical electric-powertrain assembly model including the developed spline model was constructed and simulated. Results according to changes of key factors including spline pitch errors and shaft alignment errors were analyzed. Spline radial force has been identified as an excitation source of spline induced rumble noise. This was verified through comparison with the forced vibration analysis result and time domain analysis result. This paper presents two methods for simulating spline rumble, including the key contributing factors of spline pitch errors, shaft alignment errors and unbalanced mass. Time domain method is accurate but slow. So, a faster, lower fidelity quasi-static approach has been developed and verified using time domain analysis results. Finally, an analysis process for each development stage has been established utilizing the two simulation methods. In concept design stage, quasi-static analysis is appropriate to identify robust structure for rumble noise. In detailed design stage, manufacturing tolerances could be adjusted by reviewing various conditions for rumble noise through quasi-static analysis, and a direct response review through time domain analysis is also useful to check for problems.
Drag Torque Analytical 3D Model Development for a Driveline System using a Probability Transformation
Authors: Frenz Eric R , Martinez Carlos , Garvey Thomas , Murtagh Jason
Published: April 2023

Measuring and modeling parasitic losses in driveline components continues to be an important topic in product development. There are existing standards (SAE J2985 [1], J3039[2], and J3218[3]) for measuring and reporting spin loss parasitic losses. All these tests are conducted at fixed temperatures of 28°C and 65°C with a variety of controls and measurement positions to ensure these conditions. The limitation of these methods is that they do not represent the actual vehicle range of operating temperatures. In 2020, Guarino et al presented the paper SAE 2020-01-1413 [4] on development of a test method for beam axles (which was developed into SAE J3218). In the paper, a floating temperature sweep test method was developed for testing efficiency over a range of temperature at a fixed operating condition.

This paper will highlight adapting the efficiency floating temperature sweep test method and applying it to spin loss measurement (a transfer case was used in this development). To extend value to the measurements, the measurements were combined to create a surface map to be used in vehicle modeling. The development of the process to create the surface map will be reviewed and applied in a sensitivity of the system to different factors (such as, temperature and speed). The result is a spin loss speed-temperature-torque surface map / equation and a proposed test method that is faster with reduced complexity of setup.
Analytical Study on the Fuel-Saving Potentials of a Series Hybrid Electric Vehicle
Authors: Liu Kangjie , Han Zhiyu
Published: April 2023

The fuel-saving potential of a series hybrid electric vehicle (SHEV) was investigated in this work based on the future goals and technical roadmaps proposed by China's automobile and internal combustion engine (ICE) industry. The genetic algorithm optimization method and dynamic programming energy management strategy are used to optimize the key component parameters of a typical SHEV SUV to improve the fuel economy of the vehicle. Results showed that the fuel consumption of the vehicle would be 3.24 L / 100km in 2035, which is 37.21% less than 5.16 L / 100km in 2020, following the industries’ roadmaps. The results also indicated that the improvement of the ICE’s thermal efficiency is the main reason for the decrease of the vehicle’s fuel consumption. In addition, the improvement of working points and the reduction of energy losses of the key components also contribute to the improvement of the fuel economy.
Development of e-AWD Hybrid System with Turbo Engine for SUVs
Authors: Sasaki Koichi , Kamichi Kensuke , Ishimoto Manabu , Kojima Sei , Bridge Alistair , Takebayashi Noritaka
Published: April 2023

This paper describes the development of a new e-AWD hybrid system developed for SUVs. This hybrid system consists of a high-torque 2.4-liter turbocharged engine and a front unit that contains a 6-speed automatic transmission, an electric motor, and an inverter. It also includes a rear eAxle unit that contains a water-cooled high-power motor, an inverter, and a reduction gear, as well as a bipolar nickel-metal hydride battery. By combining a turbo engine that can output high torque across a wide range of engine rpm with two electric motors (front and rear), this system achieves both smooth acceleration with a torquey driving feeling and rapid response when the accelerator pedal is pressed. In addition, new AWD control using the water-cooled rear motor realized more stable cornering performance than the previous e-AWD system. By developing a hybrid system with appealing new driving characteristics, it was possible to increase the variety of electric powertrains available to customers as part of measures to help achieve carbon neutrality.
Hydrogen Hybrid ICE Powertrains with Ultra-Low NO x Emissions in Non-Road Mobile Machinery
Authors: Aschauer Thomas , Roiser Sebastian , Schutting Eberhard , Eichlseder Helmut , Lindenthaler David , Falbesoner Florian , Ratzinger Josef , Hammerle Ulrich
Published: April 2023

In this paper, we will show the potentials of reducing NOx emissions of an H2-ICE to an ultra-low level by hybridizing the H2-ICE in an NRMM powertrain. Real-world measurement data of NRMM together with a simulated hybrid powertrain and operating strategy form the input data for the H2-ICE on the test bench. We have modified a turbocharged four-cylinder in-line gasoline engine for use with directly injected hydrogen. Within several iteration loops, we obtained measurement data that shows that, depending on the operating strategy, ultra-low NOx emissions are reachable. The combination of hybridization, which implies the possibility of recuperation, and the CO2 emission-free H2-ICE leads to a highly efficient, robust, and economic drivetrain with the lowest emissions, perfectly suitable for Non-Road Machinery.

Additionally, we will discuss the overall coupled measurement and simulation setup and the reachable NOx emission levels in our tested setup. We will give an outlook for additional NOx emission reduction potentials with exhaust after-treatment systems and other methods of further reducing nitric oxides, which can take the H2-ICE to near zero NOx emissions.
Trade-Offs and Opportunities to Improve Hybrid Vehicle Performance, Cost and Fuel Economy through Better Component Technology and Sizing
Authors: Nieto Prada Daniela , Vijayagopal Ram , Costanzo Vincent
Published: April 2023

Hybrid electric vehicles (HEVs) have seen tremendous improvements in performance, fuel economy and cost over the last two decades. As battery and motor prices decrease, HEVs are likely to be even more attractive to consumers. This study considers how HEVs can improve and whether advancements in engines and other components will play a large role in the HEV segment. Past studies have relied on a rule-based component sizing approach for hybrids to meet certain performance criteria. By going beyond this approach, we can explore the design space by varying engine power and electric drivetrain power. This can provide more insights into the fuel-saving potential of HEVs, and the trade-offs required on performance or cost characteristics to achieve those savings.

In this study, we examine the fuel-saving potential of three main hybrid powertrain architectures (parallel, series, and power-split) with varying degrees of hybridization (DOH) and using various engine technologies. With a simple set of assumptions, we show that further optimization of HEVs is possible. Our study reveals that parallel HEVs could achieve up to 20% fuel savings over start-stop systems, without incurring any additional expense for the end user. Sensitivity of total cost of ownership (TCO) to miles driven by users is also examined. We see that higher DOH may not be economically attractive for everyone, but taxis or other vehicles that run longer distances can adopt higher DOH with economic benefits. Finally, we quantify the possible fuel savings with a relaxed performance requirement.
Light Duty Battery Electric Vehicle – Battery Degradation Modeling
Authors: Saxena Sparsh , Kudachi Bharat , Pasupathi Santhosh , Bergsieker Gerald
Published: April 2023

This paper presents a case study conducted by Isuzu Technical Center of America on calculating Lithium-ion battery degradation patterns. For hybrid electric cars, plug-in hybrid electric vehicles (PHEVs), and all-electric vehicles, energy storage technologies, and batteries are often necessary (HEVs). As soon as these batteries are used for the first time, they begin to deteriorate. This is due to the battery's inherent chemistry which results in inevitable chemical reactions that happen inside the battery while it is running. ISUZU engineers are using the GT-AutoLion tool to predictively model the electrochemical processes within Lithium-ion cells using a fast and reliable, electrochemical, physics-based approach and real-world battery information. To feed this tool, we gathered valuable battery information from a light-duty BEV Prototype. The information was recorded at 3 different milestones: BOT (beginning of the test), 7500 miles, and 15000 miles. After analyzing this data at each milestone, it is observed that the battery was degraded by 8.09% after a 7500-mile run and decreased significantly to 10.42% of overall battery capacity at 15k miles, such similar patterns were also observed in the developed battery model, The battery degradation patterns generated by the developed battery model will be used to predict battery performance and improve range estimation by ISUZU.
Lowering Vehicle Powertrain Electrification Entry Cost Barrier
Authors: Nwoke Ugo
Published: April 2023

Current hybrid and electric powertrains in Class 1 through to Class 7 vehicle segments, are still disadvantaged by very low market penetration due to high procurement and operational cost barriers which have increased the gap between the technology experience and the expected benefits of powertrain electrification.

Fundamentally, baseline gasoline and diesel vehicles with over 100 years of established supply chain network and manufacturing economies of scale, have made it difficult for hybrid and electric alternatives to compete even with the continuous drop in price of these new technologies and numerous government incentives.

A new approach is proposed in this segment with an Integrated Torque Assist Transmission (ITAT) that addresses the typical fuel inefficiency challenges of the baseline powertrains where mostly up to 12% of their fuel content is used for actual vehicle propulsion while the rest is lost to heat dissipation. The new ITAT replaces the stock transmission as an electrification upgrade with the choice of a Battery or Ultracap energy storage system of 48V or 300V specification. The transmission system can be retrofitted as an aftermarket upgrade or installed on the assembly line.

A model cargo van is used to demonstrate the benefits of the torque assist transmission approach which includes engine downsizing if applicable or better fuel economy from the stock engine if it is retained as well as the cost benefit of over 60% off the shelf component sourcing using most of the existing supply chain and manufacturing infrastructure.
Fuel Cell Electric Vehicle Modeling Using Hybrid/Battery/Fuel Cell Vehicle Modeling Tool (HBFCMT)
Authors: yang bo
Published: April 2023

Fuel cell electric vehicle is one of the powertrain paths to reach zero emission suggested by many different government and research institutes. This paper shows a convenient tool to model fuel cell electric vehicle performance with simple input. By using an in-house developed hybrid/battery/fuel cell vehicle modeling tool (HBFCMT), the fuel cell powertrain combination can be analyzed with the assumption of certain control strategy. One example of light duty passenger vehicle is analyzed using this tool. Corresponding vehicle and fuel cell performance data are presented. Compared with test data, the model results are within the expectation in trend wise. Overall, the difference between the model and test data is 6.1% regarding the key performance data: hydrogen consumption in the WLTC cycle. Such conclusion is reasonable to justify the application of the modelling tool in new energy fuel cell electric vehicle design and developments.
CFD Analysis of Fuel Cell Humidification System for Automotive Application
Authors: Carello Massimiliana , Landolfi Silvio , Rizzello Alessandro , Khadilkar Sumit
Published: April 2023

Fuel cells are considered one of the promising technologies as possible replacement of Internal Combustion Engine (ICE) for the transportation sector due to their high efficiency, ultra-low (or zero) emissions and for the higher drive range.

The Membrane Electrode Assembly (MEA) is what mainly influences the Fuel Cell FC performance, durability, and cost. In PEMFC the proton conductivity of the membrane is a function of the humidification level of the FC membrane, hence the importance of keeping the membrane properly humidified to achieve the best possible fuel cell performance. To have the optimal water content inside the fuel cell’s membrane several strategies could be adopted, dealing with the use of external device (such as membrane humidifier) or to adopt an optimal set of parameters (gas flow rate and temperature for example) to use the water produced at fuel cell cathode as humidity source.

The aim of this paper is to study the behavior of a FC vehicle humidification system. Starting from experimental tests properly made with a commercial system, two different designs of the humidifier have been proposed. For both solutions, a CFD model has been developed to analyze the pressure drop and velocity. The membrane is modeled as a porous media to reduce the computational cost of the virtual CFD simulation.

The simulation results have allowed to compare the two different proposed designs, performing a sensitivity analysis of the expected performances of the humidifier itself.
Systematic Development Approach for a Hybrid Electric Powertrain Using Fuel-Cell-in-the-Loop Test Methodology
Authors: Steindl Christoph , Hofmann Peter
Published: April 2023

A promising approach for defossilization in the transport sector is using the polymer electrolyte membrane fuel cell (PEMFC) as an energy converter for propulsion in combination with green hydrogen. Furthermore, hybridization can bring an additional gain in efficiency. In a hybrid electric vehicle (HEV) powertrain, including FCHEV, at least two power sources (e.g., an FC system (FCS) with a hydrogen storage system and a high-voltage battery (HVB)) provide the required propulsion power. Thus, the powertrain topology and the energy management strategy (EMS) of an FCHEV are more complex than those of a conventional powertrain. To ensure a cost- and time-efficient development process, the FCHEV powertrain concept and its functions must be verified and evaluated early. To this end, this study presents the design and setup of an FC-in-the-Loop (FCiL) test platform as a tool for the systematic development of an FCHEV powertrain under realistic operating conditions. Hence, a medium size FCHEV is modeled with quasistatic sub-models of the powertrain components. The full-vehicle model is validated against measurement data of a commercially available FCHEV on a 4-wheel chassis dynamometer in a driving cycle. Based on the FCiL test methodology, the sizing of the FCS and HVB is demonstrated. It is found that for a low-load driving cycle such as the WLTC, a 110 kW FCS, and a 1.6 kWh HVB can achieve a good result regarding low hydrogen consumption. Furthermore, two different EMS schemes, the power follower strategy (PFS) and the equivalent consumption minimization strategy (ECMS), are implemented and evaluated. With the ECMS, hydrogen consumption can be reduced by 1.6 % compared to the PFS. Moreover, the trade-off behavior between minimum hydrogen consumption and reduced dynamics of the FCS is investigated. Reducing the dynamic operation of the FCS by one-third results in an additional hydrogen consumption of only about 0.8 %.
Low Frequency Impedance Spectroscopy – Modeling Study on the Transferability of Solid Diffusion Coefficients
Authors: Wurzenberger Johann C. , Lechner Christoph , Chen Chao , Kolmbauer Michael , Mele Igor , Katrasnik Tomaz
Published: April 2023

This work elaborates the transferability of electrode diffusion coefficients gained from fitting procedures in frequency domain to an electrochemical battery model run in time domain. An electrochemical battery model of an NMC622 half-cell electrode is simulated with sinusoidal current excitations at different frequencies. The current and voltage signals are analyzed in frequency domain via Nyquist and Bode plots. The frequency domain analysis of time domain simulations is applied to assess the numerical convergence of the simulation and the sensitivity on particle diameter, electrode and electrolyte diffusion coefficients. The simulated frequency spectra are used to fit the electrode diffusion coefficient by means of different electrical equivalent circuit models and the electrochemical battery model itself. The fitted diffusion coefficients from the different electrical equivalent circuit models deviate by one order of magnitude from the a priori known reference data. The fitting results from the electrochemical battery model show a perfect match and the corresponding simulation times underline the feasibility of this fitting approach. The impact of different electrode diffusion coefficients is further assessed by constant current discharge and pulse discharge simulations at different C-rates. The voltage responses deviate in the range of 20 mV for the 2C discharge pulse.
Topology Optimization Design on Cooling-Plate for Lithium-ion Battery Based on Electro-Thermal Model
Authors: Lin Zhenmao , Ding Kangjie , Xie Beichen
Published: April 2023

A flow channel design of the battery liquid cooling plate is carried out through the variable density topology optimization method according to the heat dissipation requirements of lithium-ion power batteries under actual working conditions. Firstly, given the non-uniform heat generation of lithium battery cells, the heat generation mechanism is studied so that the battery electro-thermal model is established, then the distribution regularity of heat generation rate in the cell at different discharge rates is obtained. Subsequently, through COMSOL Multiphysics simulation software, the multi-objective topology optimization of the primary configuration radiator is conducted. The weights of the optimization objectives minimum temperature and minimum flow resistance are determined by practical engineering application. Finally, an optimized model with a volume fraction of 50% was obtained. Based on this optimized design result, research and analysis of related fluid flow and heat transfer characteristics were conducted through numerical simulation. The results show that, under the same battery cooling demand, compared with the traditional design of the serpentine radiator, the energy consumption and the pressure drop decrease by 90.22% and 41.35% respectively at a slight cost of temperature rise. It has been proved that the topology-optimized cooling plate proposed in this paper help improve the comprehensive performance of lithium battery thermal management.
Real-World Aging Prediction of a Lithium-Ion Battery Using a Simulation-Driven Approach
Authors: Chopra Ujjwal , Biju Nikhil
Published: April 2023

A large increase in GHG emissions has led to a substantial increase in EV adoption. Due to its complexity, predicting the states of LIB remains to be a roadblock for mass adoption. Furthermore, the ability to predict the performance of an EV through its lifetime continues to be a difficult task. The following work provides how a detailed electro-thermal P2D battery model, GT-AutoLion1D, can be implemented along with a 1D vehicle model to predict how the system will age over 40 weeks of operation. The battery is calibrated using experimental data and is capable of predicting performance and aging. It considers aging mechanisms like solid electrolyte interphase (SEI) layer growth, active material isolation (AMI), and SEI cracking. It is also coupled with a lumped thermal model. The 1D vehicle model considers aerodynamic, rolling resistance, driveline inefficiency, motor-inverter losses, battery resistive losses and auxiliaries. The results showed that simulation is over 30000 times faster than real time and the capacity decreased over 7% assuming a recurrent weekly routine and charging pattern.
Cylindrical Li-Ion Cell Crush CAE Capability in Automotive Application
Authors: Bhavsar Tejas , Kanvinde Gaurav , Seshadri Sriram , Lakkannavar Virupakshappa
Published: April 2023

The world is moving towards E-mobility solutions and Battery Electric Vehicles (BEVs) are the main enabler towards it. Li-ion cells are the fundamental building block of any BEVs. There are three common types of Li-ion cell design i.e., cylindrical cells, Prismatic Cells and Pouch cells. Ensuring safety of BEVs are critical to gain customer trust and acceptance over Internal Combustion Engine (ICE) vehicles. EV fire is found to be one of the major concerns related to using higher energy batteries. During a crash event, Post-Crash Electrical Integrity of the BEV is to be ensured and hence primary focus is on mitigation of Li-ion cell internal short circuit. It has been seen in prior published articles that cell internal short circuit can be triggered by physical intrusion of cell. This paper primarily focusses on simulating the mechanical behavior of cylindrical cell under various crush conditions. In this paper, we will discuss about the trade-off between Computer Aided Engineering (CAE) model fidelity of cylindrical Li-ion cell & usage of such models in full vehicle crash simulations in LS-DYNA®. Proposed method for Cell CAE model is validated against 3 different crush tests conducted. This approach has shown acceptable accuracy for crushability in all 3 test conditions with reduced modeling complexity when compared with prior published work. Proposed Cell CAE model is found to be compatible in use with full vehicle level crash simulations, thus helps in predicting Li-ion cell intrusion accurately during crash simulations of BEVs.
Simplified Modeling of an Innovative Heating Circuit for Battery Pack Based on Traction Motor Drive System
Authors: Huang Ranjun , Wang Xinjian , Dai Haifeng
Published: April 2023

Alternating current (AC) heating is an efficient and homogeneous manner to warm Lithium-ion batteries (LIBs) up. The integrated design of AC heating combined with the motor drive circuit has been studied by many scholars. However, the problems of excessive heating frequency (>1kHz) and zeros torque output of the motor during the heating process have not been solved. High-frequency AC excitation may be detrimental to the battery because the effect of high-frequency AC excitation on the state of health of the battery is unknown. In addition, although the zero-torque output can be realized by controlling the q-axis current to zero, the torque ripple is still difficult to eliminate in a real-world application. To further solve the above problems, the motor’s neutral conductor is pulled out and connected to a large capacitor to increase the current amplitude of the AC heating at low frequencies. To quickly evaluate the AC that the heating system can generate, a simplified equivalent circuit model is established. And a new numerical solution algorithm is proposed to solve the nonlinear model. Finally, the capability of the system is evaluated using a specific set of parameters. The results show that the proposed algorithm can approximately solve the nonlinear model with a limited number of iterations. And the evaluation results of the heating system indicate that the heating system can quickly heat the battery pack. Compared with other works, the theoretical temperature rise rate is greater than 2.29°C/min. The battery pack heating scheme will promote the application of electric vehicles (EVs) in cold regions.
Thermal Management Design and Simulation of Symmetric Air-Cooled System for Lithium Battery
Authors: Ding Kangjie , Lin Zhenmao , Xie Beichen
Published: April 2023

Good heat dissipation of Lithium battery can prevent the battery from shortening its life due to rapid aging or thermal runaway. In this paper, an air-cooled structure of 5 series and 3 parallel battery packs is designed, which combines the advantages of series and parallel air ducts and optimizes the heat dissipation effect and the space ratio of air ducts. First, the heat generation model of NCR18650PF lithium battery is established, and the heat generation rate and time under different discharge rates are calculated. Combined with the working conditions of the battery itself, the necessity of battery pack heat dissipation was found. Secondly, a preliminary three-dimensional model of the battery pack heat dissipation was established, and a simulation analysis was carried out to study the influence of the inclination angle of the inlet duct, the arrangement of the air inlet and outlet, and the influence of the deflector on the heat dissipation effect, and the optimization analysis was carried out step by step according to the simulation results. It is found that, under the premise of symmetrical arrangement of air inlet and outlet, the inlet duct inclination angle is set to 10°, which can achieve better economic efficiency with smaller model size and lower manufacturing cost. In addition, two deflectors in the center of the model and heat dissipation holes on both sides of the shell can achieve the best heat dissipation effect and minimize the temperature difference of battery discharge. Finally, when the room temperature is 298 K, the discharge rate is 2C, and the air inlet speed is 3 m/s, the maximum temperature of the battery pack is 305.34 K, which is 3.75 K lower than the series air duct and 2.78 K lower than the parallel air duct, while the temperature difference drops to 4.68 K compared with the conventional air duct, indicating that the overall temperature uniformity and heat dissipation of the battery pack with the heat dissipation structure designed in this paper is better.
Estimating Battery State-of-Charge using Machine Learning and Physics-Based Models
Authors: Sapra Harsh Darshan , Wagner Michael , Kokjohn Sage , Desorcy Lukas , Upadhya Sahana , Kweon Chol-Bum , Venkataraman Shivaram , Shumaker Justin , Elfimova Olesia
Published: April 2023

Lithium-ion and Lithium polymer batteries are fast becoming ubiquitous in high-discharge rate applications for military and non-military systems. Applications such as small aerial vehicles and energy transfer systems can often function at C-rates greater than 1. To maximize system endurance and battery health, there is a need for models capable of precisely estimating the battery state-of-charge (SoC) under all temperature and loading conditions. However, the ability to perform state estimation consistently and accurately to within 1% error has remained unsolved. Doing so can offer enhanced endurance, safety, reliability, and planning, and additionally, simplify energy management. Therefore, the work presented in this paper aims to study and develop experimentally validated mathematical models capable of high-accuracy battery SoC estimation. In this work, experiments are performed with Lithium Polymer battery cells to measure performance parameters such as current, battery capacity, temperatures, and voltage. Next, physics-based and machine learning modeling approaches are developed to study their ability to predict SoC. Measurements performed at high C-rates (1C – 4C) are used for model training and calibration, validation, and testing. The results show that the Pseudo-2D electrochemical model can predict SoC within about 2 % root-mean-squared-error (RMSE) at different C-rates. However, the Feed Forward Neural Network modeling approach with Butterworth and Hampel filters achieved lower than and close to 1 % RMSE for battery SoC estimations.
Development of Cell to Body Technology towards High Levels of Integration, High Strength and High Stiffness
Authors: Lian Yubo , Ling Heping , Jiang Long , Yi Bengang , Zhang Fengli , Liu Jianjian , Song Gan , Tang Meng
Published: April 2023

Rapid technological advancement of electric vehicles (EV) contributed to a significant increase of its market share worldwide. Among them battery technologies are key in extending the range of battery electric vehicles (BEV) and easing range anxiety for drivers. To further enhance the range for BEVs, continued downsizing of the battery system together with an increased energy density would be required. Cell to body (CTB) technology was release by BYD Auto in 2022 as its answer to the next generation of battery pack design and system level integration. The battery pack features a sandwich structure that consists of an upper cover, the company’s signature Blade Battery cells, and an underbody protection tray. The battery pack features a higher level of integration, with the volume utilization rate increasing to 66%. The integrated battery pack-body structure enhances its structural strength, with significant reductions in the intrusions across front, small-overlap and side pole impacts. 70% and 57% increases in the torsional and the bending stiffness of the body results in better handling performance and improved passenger comfort. The CTB technology has shown its great potential for high performance BEV design.