bluuebunny/crossref_metadata_2025 huggingface dataset:
Split Injection of High-Ethanol Content Fuels to Reduce Knock in Spark Ignition
Authors: Gainey Brian , Gandolfo John , Gao Mingyang , Lawler Benjamin
Published: April 2023

Spark ignition engines have low tailpipe criteria pollutants due to their stoichiometric operation and three-way catalysis and are highly controllable. However, one of their main drawbacks is that the compression ratio is low due to knock, which incurs an efficiency penalty. With a global push towards low-lifecycle-carbon renewable fuels, high-octane alternatives to gasoline such as ethanol are attractive options as fuels for spark ignition engines. Under premixed spark ignition operating conditions, ethanol can enable higher compression ratios than regular-grade gasoline due to its high octane number. The high cooling potential of high-ethanol content gasolines, like E85, or of ethanol-water blends, like hydrous ethanol, can be leveraged to further reduce knock and enable higher compression ratios as well as further downsizing and boosting to reduce frictional and throttling losses.

In this work, a split injection strategy is used, where 5-15% of the total injected fuel is injected during the compression stroke with E75 gasoline (75% ethanol, by volume) and hydrous ethanol (190 proof ethanol, 92% ethanol, 8% water, by mass). These experimental results indicate that injecting a small amount of E75 or WE92 during the middle of the compression stroke such that the fuel cannot completely homogenize with the air before the spark fires results in knock mitigation that exceeds the amount of knock mitigation expected by evaporating that amount of fuel in air in a premixed setting. This split injection strategy achieved a 1.3% relative fuel conversion efficiency benefit with E75 at 19 bar IMEPn and a 1.4% relative fuel conversion efficiency benefit at 15 bar IMEPn with WE92. Overall, these results indicate that a split injection strategy with a high cooling potential alcohol fuel can further increase a fuel’s effective octane number, enabling highly boosted, high compression ratio stoichiometric spark ignition operation.
Combustion Characteristics of Iso-Octane/Hydrogen Flames under T and P Effects up to near Flammability Limits
Authors: Akram M. Zuhaib , Aziz Muhammad , Ma Fanhua , Deng Yangbo , Akram M. Waqar , Akhtar Ali
Published: April 2023

Lean combustion is an approach to achieving higher thermal efficiency for spark ignition engines. However, it faces low burning velocity and unstable combustion problems near the lean flammability limits region. The current work is attempting to investigate the combustion characteristics of iso-octane flame with 0% and 30% H2 up to near lean limits (λ = 1.7) at 100-300 kPa and 393-453 K. The flame appeared spherically by 37 mJ spark energy at λ = 0.8-1.2, whereas the ultra-lean mixtures, λ ≥ 1.3, ignited at 3000 mJ under wrinkles and buoyancy effects. The impact of initial pressure and temperature on the lean mixture was stronger than the stoichiometric mixture regarding flame radius and diffusional-thermal instability. The buoyancy appeared at the highest burning velocity of 27.41 cm/s. The buoyancy region extended from λ = 1.5 to λ = 1.3 at 393 K, λ = 1.6 to λ= 1.4 at 423 K and λ = 1.7 to λ = 1.5 at 453 K with an increase in initial pressure (higher pressure, more λ under buoyancy effect), but initial temperature decreased the region from λ= 1.5 to λ = 1.7 at 100 kPa, λ = 1.4 to λ = 1.6 at 200 kPa and λ = 1.3 to λ = 1.5 at 300 kPa. OH mole fraction <7.6642×10-3 for H2 = 0% and <7.7765×10-3 for H2 = 30% required 3000 mJ for ignition at 393 K and 100 kPa, and buoyancy appeared at ≤4.8788×10-3 for H2 = 0% and ≤4.9547×10-3 for H2 = 30%.
A Numerical Approach for the Analysis of Hydrotreated Vegetable Oil and Dimethoxy Methane Blends as Low-Carbon Alternative Fuel in Compression Ignition Engines
Authors: Garcia-Oliver Jose M , Novella Ricardo , Lopez Pintor Dario , Micó Carlos , Bin-Khalid Usama
Published: April 2023

Despite recent advances towards powertrain electrification as a solution to mitigate pollutant emissions from road transport, synthetic fuels (especially e- fuels) still have a major role to play in applications where electrification will not be viable in short-medium term. Among e-fuels, oxymethylene ethers are getting serious interest within the scientific community and industry. Dimethoxy methane (OME1) is the smaller molecule among this group, which is of special interest due to its low soot formation. However, its application is still limited mainly due to its low lower heating value. In contrast, other fuel alternatives like hydrogenated vegetable oil (HVO) are considered as drop-in solutions thanks to their very similar properties and molecular composition to that of fossil diesel. However, their pollutant emission improvement is limited. This work proposes the combination of OME1 and HVO as an alternative to fossil diesel, to achieve noticeable soot emission reductions while compensating for the different properties of the first fuel.

The aim of this work is to provide insight into the combustion characteristics of blends of these two fuels. For this purpose, experimental and numerical studies are combined. In this context, n-dodecane is proposed as a surrogate for HVO simulation based on the high similarities experimentally observed between both fuels. Then, a compact kinetic mechanism is developed and validated, combining individual OME1 and n-dodecane mechanisms. Results confirm that the numerical approach followed was able to capture the experimental behavior of these blends in terms of heat release rate, in-cylinder pressure and soot formation. An increase of the OME1 content in the blend greatly influences the combustion process. The ignition delay, as well as the premixed combustion phase peak, increase with the OME1 percentage in the blend. However, HVO helps on limiting this effect while remarkable soot formation reductions are still achieved thanks to OME1.
Experimental Investigation of Combustion Characteristics, Performance, and Emissions of a Spark Ignition Engine with 2
nd
Generation Bio-Gasoline and Ethanol Fuels
Authors: Mohamed Mohamed , Zhao Hua , Harrington Anthony , Hall Jonathan
Published: April 2023

Climate change mitigation is the main challenge for the automotive industry, as the government issues legislation to combat CO2 emissions. In addition to electrification and battery electric vehicles, using low-carbon and zero-carbon fuels in Internal Combustion (IC) engines can also be an effective way to reach net zero-carbon transport.

This study investigated and compared the combustion characteristics, performance and emissions of a highly boosted spark ignition (SI) engine fuelled with EU VI 95 RON E10 gasoline and blends of second-generation bio-gasoline with different ethanol contents of 5% (E5), 10% (E10), and 20% (E20). The single-cylinder SI engine was equipped with a centrally mounted high-pressure injector and supplied externally boosted air. Engine experiments were conducted at 2000 RPM and 3000 RPM with low and high load operations.

The overall finding indicates that increasing the ethanol content of second-generation biofuels from 5% to 20% improves the indicated thermal efficiency at low load by 2.1% and increases the knock resistance by 16.8% at high load operation as well as a reduction by 0.7% on cycle-to-cycle variation. The engine emissions were primarily affected by the engine operating conditions, and no consistent correlation between the ethanol content and emissions. However, it was noted that the average NOx and THC emissions were increased by 11.02% and 66%, respectively, at the low load operation when the ethanol content was increased from 5% to 20% at the exact fuel injection timing of 350 BTDC.
Unified Net Willans Line Model for Estimating the Energy Consumption of Battery Electric Vehicles
Authors: Li Candy Yuan , Nelson Douglas
Published: April 2023

Due to increased urgency regarding environmental concerns within the transportation industry, sustainable solutions for combating climate change are in high demand. One solution is a widespread transition from internal combustion engine vehicles (ICEVs) to battery electric vehicles (BEVs). To facilitate this transition, reliable energy consumption modeling is desired for providing quick, high-level estimations for a BEV without requiring extensive vehicle and computational resources. Therefore, the goal of this paper is to create a simple, yet reliable vehicle model, that can estimate the energy consumption of most electric vehicles on the market by using parameter normalization techniques. These vehicle parameters include the vehicle test weight and performance to obtain a unified net Willans line to describe the input/output power using a linear relationship. A base model and three normalized models are developed by fitting the UDDS and HWFET energy consumption test data published by the EPA for all BEVs in the U.S. market. Out of the models analyzed, normalizing by weight performs best with the lowest RMSE values at 0.384 kW, 0.747 kW, and 0.988 kW for predicting the UDDS, HWY, and US06 data points, respectively, and 0.653 kW using the combined data of all three data sets. Consideration of accessory loads at 0.5 kW improves the model normalized by weight and performance by a reduction of over 20% in RMSE for predictions with all data sets combined. Removing outliers in addition to the consideration of accessory loads improves the model normalized by weight and performance by a reduction of over 36% in RMSE for predictions with all data sets combined. Overall, results suggest that a unified net Willans line is largely achievable with accessible energy consumption data on U.S. regulatory cycles.
Technology Levers for Meeting 2027 NOx and CO
2
Regulations
Authors: McCarthy, Jr. James E. , Zavala Bryan , Matheaus Andrew
Published: April 2023

Commercial vehicles require fast aftertreatment heat-up to move the SCR catalyst into the most efficient temperature range to meet upcoming NOX regulations while minimizing CO2. The focus of this paper is to identify the technology levers when used independently and also together for the purpose of NOX and CO2 reduction toward achieving 2027 emissions levels while remaining CO2 neutral or better. A series of independent levers including cylinder deactivation, LO-SCR, electric aftertreatment heating and fuel burner technologies were explored. All fell short for meeting the 2027 CARB transient emission targets when used independently. However, the combinations of two of these levers were shown to approach the goal of transient emissions with one configuration meeting the requirement. Finally, the combination of three independent levers were shown to achieve 40% margin for meeting 2027 transient NOx emissions while remaining CO2 neutral. These independent levers and combinations were also quantified for meeting the new Low Load Cycle. This paper shows which combinations of technologies meets both the transient emission cycles and low load cycles for NOx with adequate margin while also saving CO2.
High Cell Density Flow Through Substrate for New Regulations
Authors: Nakasumi Hayaki , Kawakami Akifumi , Ohara Etsuji , sugimoto Kentaro , Hibi Noriyuki , Asako Tsuyoshi , Kato Kyohei , Anoop Reghunathan-Nair , Affan Syed , Thanasiu Eva , Lambert Christine K. , Hubbard Carolyn
Published: April 2023

This paper, written in collaboration with Ford, evaluates the effectiveness of higher cell density combined with higher porosity, lower thermal mass substrates for emission control capability on a customized, RDE (Real Driving Emissions)-type of test cycle run on a chassis dynamometer using a gasoline passenger car fitted with a three-way catalyst (TWC) system. Cold-start emissions contribute most of the emissions control challenge, especially in the case of a very rigorous cold-start. The majority of tailpipe emissions occur during the first 30 seconds of the drive cycle. For the early engine startup phase, higher porosity substrates are developed as one part of the solution. In addition, further emission improvement is expected by increasing the specific surface area (GSA) of the substrate. This test was designed specifically to stress the cold start performance of the catalyst by using a short, 5 second idle time preceding an aggressive, high exhaust mass flowrate drive cycle. The evaluation results showed that the substrate with the lowest ratio of bulk density to GSA had the best cold-start emissions control capability, with 21% lower NMHC and 30% lower NOx during the first phase of the aggressive cold start drive cycle compared to a standard porosity substrate. A cell density higher than 1000 cells/in2 was found to be 32% more effective than a standard 900 cells/in2 substrate at controlling high space velocity, higher temperature NMHC+NOx emissions. The paper concludes with the development status of next generation higher porosity, higher cell density ceramic substrates.
Low Ambient Temperature Impact on a Low NO
X
Demonstration System
Authors: Zavala Bryan , Sharp Christopher
Published: April 2023

In 2020, CARB adopted the low NOX omnibus ruling, which provided revisions to on-road heavy duty engine compliance standards and certification practices. As part of the updates to the regulation, CARB has introduced a new in-use vehicle testing process that broadens the operation modes tested and considers the manufacturer’s intended vehicle application. Compared to the previous method, or the Not-to-Exceed approach, cold start and low ambient temperature provisions were included as part of the updates. The inclusion of low temperature operation requires the OEMs to design a robust engine and aftertreatment package that extends NOX conversion performance. The following work discusses the NOX emissions performance impact in a low temperature ambient environment. The engine and aftertreatment system evaluated was designed to comply with CARB’s low NOX regulations. The cycles tested included the CARB Southern NTE cycle and an FTP-LLC protocol. Both test sequences were intended to replicate drive cycles observed in the field. Overall, results indicated higher emissions for the low ambient temperature conditions. Utilizing the 3-bin moving average window method, emissions results were calculated for idle, low load, and medium / high load bins. While the CARB Southern NTE cycle showed an increase in the idle and low load bins, the system was able to maintain compliance. The medium / high load bin, however, exceeded the compliance limit by ~40% due to changes in the exhaust conditions. For the FTP-LLC protocol, LLC segments also increased, but maintained compliance based on the 2031+ in-use NOX standards. Furthermore, low ambient temperature operation creates challenges for controlling emissions even with a low NOX system.
CFD Assessment of an After-Treatment System Equipped with Electrical Heating for the Reduction of the Catalyst Light-Off Time
Authors: Barillari Loris , Della Torre Augusto , Montenegro Gianluca , Onorati Angelo , Rossi Vincenzo , Paltrinieri Stefano , Gullino Fabrizio
Published: April 2023

The reduction of the catalyst light-off time at the engine cold start represents a key factor for the pollutant emissions control from vehicles tested on homologation cycles and real drive conditions. The adoption of heating strategies to increase the temperature of the catalytic substrate in the early phase of the engine start is regarded as a promising solution. The present study focuses on the application of electrical heated catalyst (EHC) in an after-treatment line for a spark-ignition gasoline engine. The analysis is carried out by means of an advanced CFD framework, which includes the modeling of catalytic reactions in the substrates and accounts for the thermal evolution of all the components included in the after-treatment system. In this work the model has been extended with: a) the solution of the electrical circuit of the EHC to provide an accurate description of the non-uniform temperature distribution of the coils heated by Joule effect and b) a specific model for the radiative heat transfer from the porous EHC, which plays a significant role in the thermal balance of the device. The simulation model is validated considering an experimental test configuration, suitably instrumented to provide temperature measurements at different locations under different operating conditions. Then, a complete exhaust line has been simulated, analyzing the thermal transient of the catalytic substrate during the different phases of the EHC activation. The reaction light-off in the catalyst is monitored, assessing the benefits in terms of reduction of the overall emissions with respect to the base case.
Challenges and Solutions to Meeting Eu VII Particle Number Requirements during Aggressive Field Operation
Authors: Viswanathan Sandeep , He Suhao , Reddy Vishal , Sadek Ghadi
Published: April 2023

The heavy duty (HD) Eu VII regulations, going into effect starting 2027, has aggressive particle number (PN) emissions limits under extended operating conditions compared to existing Eu VI framework. In addition to the proposed hot-start PN limit of 2.0E+11 #/kWh, which is a >65% reduction vs. Eu VI E, the particle size cut-off is being extended from 23nm+ to 10nm+ while also including nearly all field operating conditions such as regeneration events, wider ambient boundaries etc. The tighter limits coupled with a work-based window approach to evaluate emissions is driving the need for the next generation of ultra-high filtration efficiency (FE), diesel particulate filter (DPF) technologies. The current study evaluates the FE performance of different DPF solutions under development, over a range of challenging on-road conditions characterized by frequent high temperature events which are not actively triggered. The combination of higher temperatures and NOx to Soot ratios (NSR) is expected to lead to partially regenerated DPF operation increasing the likelihood of high PN slip. The cycles were developed and tuned based on data from field operation of HD linehaul trucks. We demonstrate that some of the development DPF samples could maintain >99.9% filtration efficiency even during aggressive passive operation with high NSR. The results suggest that adoption of these DPF technologies can help HD vehicle manufacturers meet the extremely stringent Eu VII PN requirements under the most challenging field operating conditions.
A Comparison of Virtual Sensors for Combustion Parameter Prediction of Gas Engines Based on Knock Sensor Signals
Authors: Kefalas Achilles , Ofner Andreas , Posch Stefan , Pirker Gerhard , Gößnitzer Clemens , Geiger Bernhard , Wimmer Andreas
Published: April 2023

Precise prediction of combustion parameters such as peak firing pressure (PFP) or crank angle of 50% burned mass fraction (MFB50) is essential for optimal engine control. These quantities are commonly determined from in-cylinder pressure sensor signals and are crucial to reach high efficiencies and low emissions. Highly accurate in-cylinder pressure sensors are only applied to test rig engines due to their high cost, limited durability and special installation conditions. Therefore, alternative approaches which employ virtual sensing based on signals from non-intrusive sensors retrieved from common knock sensors are of great interest. This paper presents a comprehensive comparison of selected approaches from literature, as well as adjusted or further developed methods to determine engine combustion parameters based on knock sensor signals. All methods are evaluated on three different engines and two different sensor positions. The investigated approaches include a convolutional neural network, extreme gradient boosting regression models, non-linear feature regression models, a partial differential equation, as well as one method based on the analysis of structure-borne sound to derive an appropriate correlation. For evaluation of these implemented methods, data was acquired from extensive measurements of two spark-ignited single-cylinder large gas engines and one dual fuel single cylinder large engine under different operating conditions. The results show that the data-driven approaches achieved a root mean squared error (RMSE) of under 5.69 bar for the PFP and a RMSE of under 0.53 ° crank angle (CA) for the MFB50 across all investigated datasets. One method from the literature was adapted for the present study by applying the continuous wavelet transform and extracting certain features from the time-frequency spectrum to establish a suitable correlation for the desired combustion parameters. By achieving RMSE values for PFP of under 5.45 bar and for MFB50 of under 1.12 ° CA over all processed datasets, this adapted, novel method demonstrated high potential for the underlying regression tasks.
Cast Iron Cylinder Blocks: Same Weight as Aluminum; Lower Emissions
Authors: Dawson Steve , Ferrarese Andre , Marquard Ralf
Published: April 2023

In comparison to aluminum, Compacted Graphite Iron (CGI) iron has superior mechanical properties, enables the use of parent bore running surfaces and fracture split main bearings, and provides advantageous NVH, package size, cost, and manufacturing CO2 profiles. Despite these advantages, aluminum blocks have leveraged density, and therefore weight, differentials to make considerable gains in the small, in-line passenger vehicle sector over the last 30 years.

In order to demonstrate the potential benefits of CGI for small, in-line spark-ignition engines, the present study converted the cylinder block of a series production 1.2 litre three-cylinder engine from aluminum to CGI. Leveraging a novel design concept, with the running surface and load path constructed from high-strength CGI and the outer crankcase housing fabricated from durable, lightweight plastic, the assembled cylinder block achieved the same weight as the original aluminum block.

NVH analyses showed that the global flexural modes of the CGI cylinder block were 5% higher than aluminum block while the four main bearing cap modes were 18~40% higher, indicating potential NVH advantages for the CGI engine. It is further noted that the design of the CGI cylinder block was constrained by the need to maintain outer dimensions and bore-centers to facilitate engine assembly for durability testing. It is estimated that a clean-sheet design could have enabled a further 5% reduction in the weight of the CGI block.

With weight parity, and the successful completion of a 100-hour durability test, CGI has established a new benchmark for small, in-line passenger vehicle engines.
Disconnect Actuator System (DAS) for AWD EV’s Driving System
Authors: Yang Sedong , Shin BongJoo , Woo Moonsik , Ahn Jongbae , lee Sangheon , Kim Yeonho , Jung Jongmoon
Published: April 2023

This paper proposes DAS(Disconnect Actuator System), a system applied to an EV’s auxiliary driving system to decrease electric consumption. The proposed DAS functions to connect or disconnect the power of the EV AWD auxiliary driving system. Also, this system has a high driving performance of AWD. When only the main driving system is driven(2WD) to improve electric efficiency in EV AWD without DAS, electric efficiency is low due to drag loss generated by the rotation of internal mechanical elements in the auxiliary driving system. To reduce the drag loss of the auxiliary driving system and has the high driving performance of the AWD, A DAS that can connect or disconnect the power between the mechanical elements of the auxiliary driving system is essential. A system analysis was performed to determine the layout of the DAS, and DAS was developed using optimization by analyzing the factors related to the NVH(Noise Vibration Harshness) and seamless shifting. The method is called ‘Seamless Methodology’ in this paper. This methodology was analyzed and evaluated using AMEsim, and verified using Dynamo test and vehicle tests. Recently, it has been applied to mass-produced AWD EVs of Hyundai and Kia Motors, improving electrical efficiency by 6 to 8.3% per vehicle, and has AWD driving performance.
Study on the Effect of Clutch Hydraulic System Hysteresis on Intermittent Clutch Pedal Stuck Concern
Authors: Mohan Gokulakkannan , Kanagaraj Pothiraj , M DEVAMANALAN , Sankaran Narayanasamy
Published: April 2023

The clutch pedal in manual transmission plays a significant role in defining the comfort of driver as it is a direct customer interfaces in the vehicle. Clutch & its hydraulic release system in manual transmission are the significant components which affects the maneuverability of the vehicle and the driver comfort.

The clutch pedal characteristics optimization is one of the vital parameters are involving various parameters like pedal effort, pedal travel, hump, engagement and disengagement travel, modulation travel & pedal return curve min load. Normally the clutch pedal characteristics has a hysteresis between the forward and return curve (depress and release of the clutch pedal). The hysteresis is the component of mechanical friction like clutch pedal, clutch cover, and hydraulic seal friction. For an optimum clutch pedal feel, free play, peak effort, max. travel, hump and return load are the major functional parameters.

This paper focus on study of the clutch pedal stuck intermittently while releasing the clutch pedal after gear shift close to the free play zone. The Clutch pedal return curve profile plays a major role for smooth pedal returnability. In this case the return curve load at 20 mm of pedal travel was lesser which eventually leading to clutch pedal stuck. CMC seal Friction plays a vital role for clutch pedal to return its home position while engaging the clutch which is controlled by optimum hysteresis in the system. The optimum hysteresis can be maintained by fine tuning the friction of clutch master cylinder seal contact profile, which having relative motion with clutch master cylinder piston while engage and disengage the clutch. The design simulation and experimental DOE is done with different seal lip profile to evaluate the friction variation and its impact on the overall hysteresis in the clutch pedal characteristics.
Data Processing and Performance Analysis of PEMFC Stacks on Urban-Route Buses
Authors: Zhang Ruojing , Zhu Haomin , Zhou Xiangyang , Zheng Weibo , Pan Xiangmin
Published: April 2023

Proton exchange membrane fuel cells are promising in the application of new energy vehicles and other fields. The performance test and analysis are critical components of the fuel cell research. A general procedure for data processing model and performance analysis method of fuel cell stacks were introduced based on a demonstration project of commercial fuel cell buses in Shanghai.

To build the data processing model, the fixed node method was used to extract the effective operating data of fuel cell stack from the vehicle database. After data cleaning and conversion, taking fuel cell reversible recession into account, the processed data can be obtained. Data that had been processed and a semi-empirical model were used to accurately fit the polarization curve. Polarization curve is a pivotal approach to describe the performance of fuel cells. The entropy method and the frequency statistics method were used to choose and weight the distinctive current densities in the polarization curve. To achieve a more thorough assessment of the performance loss of fuel cell stacks, the voltage degradation under the weighted current density was next examined.

The results show that the data processing approach was effectively fitted to fuel cell stacks, which can quickly extract and process the road data to accurately fit the polarization curve. The voltage degradation was estimated and examined at weighted current density to depict the complete performance of fuel cell stacks. Data from five cars from Shanghai demonstration projects have successfully demonstrated the effectiveness of the whole system, including data processing and performance analysis. This shows that the method is applicable to various types of data obtained through bench or road tests.
Shifting Control of 4MC-4AMT Propulsion System on Pure Electric Heavy-Duty Commercial Vehicle
Authors: Huang Wenkai
Published: April 2023

For the shifting process of the centralized central drive four motor-4AMT(4MC-4AMT) propulsion system applied on the pure electric heavy truck, there were several methodologies to fulfill it, such as torque control method, speed control method, free-speed hybrid control method and torque-speed hybrid control method, where the torque control method and torque-speed hybrid control method were applied on 4MC-4AMT. Through the simulation and test, it was found that the shifting process of torque-speed hybrid control method was much quicker than torque control one and shift smoothness was also acceptable with the same gear selection and shifting actuators.
Evaluation of Occupant Kinematics and Kinetics during Moderate Severity Simulated Frontal Impacts with and without Frontal Airbag Deployment
Authors: Sharpe Sarah S. , Grijalva Sandra , Allin Leigh , Courtney Amy , Toney-Bolger Megan , Pokutta-Paskaleva Anastassia , Crosby Charles L. , Carhart Michael
Published: April 2023

Airbag and seat belt pretensioner deployment characteristics depend on multiple factors, such as the magnitude, direction, and rate of vehicle deceleration as detected by vehicle crash sensors and evaluated by vehicle-specific algorithms. Frontal airbag and pretensioner deployments are likely to be commanded during frontal crash events with high initial vehicle deceleration typically associated with high vehicle change in velocity (delta-V). However, within a range of moderate changes in vehicle speeds, referred to as the “gray zone,” a vehicle-specific algorithm may or may not command deployment depending on crash pulse parameters and occupant sensing, among other items. Publicly available testing in the moderate-speed range is lacking and would be useful to evaluate the effects of airbag and pretensioner deployment on occupant kinematics and loading. In this study, sled tests were performed using a standard passenger vehicle buck simulating frontal deceleration impact events in a “gray-zone” severity of 19 kph (12 mph) delta-V and in a typical deployment severity of 32 kph (20 mph) delta-V. Matched sled tests were performed with and without airbag deployment with instrumented Hybrid III 50th percentile anthropomorphic test devices (ATDs) properly belted in the driver and front passenger seats. Additionally, one paired test was conducted at 19 kph with and without pretensioner deployment in the presence of airbag deployment. Airbag deployment for the 19 kph delta-V tests did not significantly affect occupant kinematics or loading compared to the non-deployment tests, while some differences were apparent for the 32 kph delta-V tests. In all tests, injury metrics were well below applicable injury assessment reference values (IARVs).
An Evaluation of External Human-Machine Interfaces and Compliance with Federal Motor Vehicle Safety Standard 108
Authors: Marulanda Susana , Britten Nicholas , Chang Chun-Cheng , Shutko John
Published: April 2023

For Automated Vehicles (AVs) to be successful, they must integrate into society in a way that makes everyone confident in how AVs work to serve people and their communities. This integration requires that AVs communicate effectively, not only with other vehicles, but with all road users, including pedestrians and cyclists. One proposed method of AV communication is through an external human-machine interface (eHMI). While many studies have evaluated eHMI solutions, few have considered their compliance with relevant Federal Motor Vehicle Safety Standards (FMVSS) and their scalability. This study evaluated the effectiveness of a lightbar eHMI to communicate AV intent by measuring user comprehension of the eHMI and its impact on pedestrians’ trust and acceptance of AVs. In a virtual reality scene, 33 participants experienced one of three eHMI conditions (no lightbar, FMVSS-compliant lightbar, non-compliant lightbar) of an AV that communicated its intent when navigating a busy intersection. On average, it required two exposures for participants to correctly describe the lightbar’s purpose. Overall, participants found the lightbar useful and satisfying, and the majority would expect and prefer that AVs be equipped with a lightbar. The FMVSS-compliant lightbar had a positive effect on people's trust in self-driving vehicles, with participants reporting the lightbar provided clearer actions of what an AV would do and was more predictable compared to the non-compliant lightbar. This study demonstrates that an FMVSS-compliant lightbar is an effective and scalable solution to the issue of AV-pedestrian communication.
Driving Style Identification Strategy Based on DS Evidence Theory
Authors: Wang Changtai , He Rui , Zhu Bing
Published: April 2023

Driving assistance system is regarded as an effective method to improve driving safety and comfort and is widely used in automobiles. However, due to the different driving styles of different drivers, their acceptance and comfort of driving assistance systems are also different, which greatly affects the driving experience. The key to solving the problem is to let the system understand the driving style and achieve humanization or personalization. This paper focuses on clustering and identification of different driving styles. In this paper, based on the driver's real vehicle experiment, a driving data acquisition platform was built, meanwhile driving conditions were set and drivers were recruited to collect driving information. In order to facilitate the identification of driving style, the correlation analysis of driving features is conducted and the principal component analysis method is used to reduce the dimension of driving features. According to the average acceleration, the headway and reciprocal of the time to collision during driving as clustering indicators, K-means algorithm is used to define driving style as aggressive, common and conservative. Different from previous studies, this paper introduces the idea of integrated learning, takes K-Nearest Neighbor, Back Propagation neural network and Support Vector Machines as the initial classifiers, and fuses the results of each classifier through DS evidence theory to obtain the recognition model of driving style, and tests the accuracy with the test set. The results show that the multi classifier fusion identification strategy proposed in this paper can clearly and accurately identify driving style, and its accuracy can reach 95.9%. At the same time, its accuracy is significantly improved compared with a single classifier, which adds a new idea to improve the accuracy of driving style identification
Forming Characteristics of Nano-Precipitation Strengthened Cold-Rolled Batch Annealed HSLA Sheet Steels (>490MPa Yield Strength)
Authors: Biswas Siddhartha , Chen Bilin , Bhartiya Shobhit , Injeti Yashwanth , Williams William , De Amar
Published: April 2023

A low carbon Ti-microalloyed chemistry was selected for the development of family of cold-rolled and batch-annealed high-strength high-formable steels through EAF-LMF-CSP route. A clean steel practice combined with a suitable choice of hot rolling and batch annealing practice were optimized to retain precipitate strengthening in the final fully processed steel and microstructural attributes that resulted in superior forming characteristics. The enhanced balance of strength and formability (hole expansion ratio values of 70-100% for thicknesses of 0.80-1.20 mm and tensile strength ranging from 571-709 MPa) attributed to the optimization of the microstructure through controlled recrystallization and grain growth. In this article, production strategy and formability characterization of high-strength low-alloy steels with minimum yield strength of 490 MPa will be discussed, and results will be presented.
Quantifying the Deceleration of Various Electric Vehicles Utilizing Regenerative Braking
Authors: Vigil Cole Mackenzie , Kaayal Omar , Szepelak Alexander
Published: April 2023

Regenerative braking is present in almost all electric vehicle models and as the demand for electric vehicles grows, the types of electric vehicles grow as well. Regenerative braking allows for an electric vehicle to convert a vehicle's kinetic energy into electrical potential energy by utilizing the electric motors to slow the vehicle. This potential energy is then returned to the vehicle’s battery allowing for the vehicle’s range to be extended. The vehicles tested during the study were as follows: 2022 Rivian R1T, 2022 Tesla Model Y, 2022 Hyundai Ioniq 5, 2020 Tesla Model 3, 2021 Volkswagen ID.4, and 2021 Ford Mustang Mach-E. Although regenerative braking slows the vehicle, not all levels of regenerative braking bring the vehicle to a complete stop. The study showed that there are typically two types of regenerative braking. The first, commonly referred to as one-pedal driving, will bring a vehicle to a complete stop without the application of the brake pedal. The other slows the vehicle to a pre-determined speed before the regenerative braking is no longer applied. This type of regenerative braking allowed the vehicle to move forward, or coast, after regenerative braking was no longer applied. This study sought to determine and compare the average deceleration from regenerative braking, without applying the brake pedal, of each vehicle at all levels of regeneration. Tests were conducted at speeds of approximately 15 mph, 30 mph, 45 mph, and 60 mph. As electric vehicles introduced the ability to change the vehicles performance and driving characteristics through software updates, it may be necessary to complete testing periodically.
Coefficient of Restitution and Collision Pulse Duration in Low-Speed Vehicle-to-Barrier Impacts
Authors: Olberding Joseph , Petroskey Karla , Leipold Tara
Published: April 2023

The coefficient of restitution is utilized in various methods for determining the change in velocity (delta-V) associated with a vehicle collision event. Additionally, for a given delta-V, the magnitude of vehicle acceleration varies with different collision pulse durations. Collision restitution and duration parameters are thus considered by both accident reconstructionists and biomechanists in the investigation of vehicle collision severity and occupant injury potential. Because of the uniqueness of individual vehicle designs, it is difficult to determine a collision’s specific coefficient of restitution and crash pulse duration. Accident reconstructionists often estimate the values of these parameters based on staged crash tests. Prior studies involving low-speed collisions have sought to determine correlations between restitution and collision characteristics and have established equations to assist in estimating restitution. Most of these equations are based around the correlation between restitution and vehicle closing speed. Furthermore, the previous work is largely based on pre-2000 model year vehicles. This study seeks to expand the restitution data for vehicle-to-barrier collisions to a more modern vehicle fleet and examine potential vehicle and collision characteristics that influence restitution and crash pulse duration. The Insurance Institute for Highway Safety (IIHS) conducted a series of low-speed vehicle-to-barrier and vehicle-to-vehicle crash tests. The IIHS test series includes both front and rear collisions with a fixed bumper-like barrier in full-overlap and corner (offset) configurations. For this study, over 100 vehicle-to-barrier front and rear full-overlap collision videos were analyzed to compute the coefficient of restitution and crash pulse duration for each test. The relationships between vehicle weight, vehicle wheelbase, bumper engagement, and bumper construction with the coefficient of restitution and pulse duration were evaluated.
Evaluation of Drivers of Very Large Pickup Trucks: Size, Seated Height and Biomechanical Responses in Drop Tests
Authors: Burnett Roger , Parenteau Chantal , Vogler Michelle , Toomey Daniel , Orlowski Kenneth , Krishnaswami Ram
Published: April 2023

This study focused on occupant responses in very large pickup trucks in rollovers and was conducted in three phases.

Phase 1 - Field data analysis: In a prior study [9], 1998 to 2020 FARS data were analyzed; Pickup truck drivers with fatality were 7.4 kg heavier and 4.6 cm taller than passenger car drivers. Most pickup truck drivers were males. Phase 1 extended the study by focusing on the drivers of very large pickup trucks. The size of 1999-2016 Ford F-250 and F-350 drivers involved in fatal crashes was analyzed by age and sex. More than 90% of drivers were males. The average male driver was 179.5 ± 7.5 cm tall and weighed 89.6 ± 18.4 kg.

Phase 2 – Surrogate study: Twenty-nine male surrogates were selected to represent the average size of male drivers of F-250 and F-350s involved in fatal crashes. On average, the volunteers weighed 88.6 ± 5.2 kg and were 180.0 ± 3.2 cm tall with a 95.2 ± 2.2 cm seated height. The volunteers were lap-shoulder belted in the driver seat of a 2002 Ford F-250 crew cab. The head-to-roof clearance was 12.8 ± 1.1 cm. It was 1.0 ± 0.6 cm once the vehicle was statically inverted.

Phase 3 – Drop tests: Three drop tests were conducted using 2002 Ford F-250 crew cab pickups. An instrumented 50th Hybrid III ATD was lap-shoulder belted in the driver seat. The ATD was modified by increasing the seated height by 5 cm, from 88 to 93 cm, to represent the average driver of very large pickups. Biomechanical responses were assessed. All were below Injury Assessment Reference Value (IARV) except for upper and lower neck. The effect of roof/pillar deformation on occupant responses was analyzed by varying the vehicle weight (3147 kg in production test v 1502 kg in the buck test) and roof/pillar strength (production v roll caged). The test data and videos were reviewed to identify time coinciding with ground contact, head-to-roof contact, peak biomechanical responses, and maximum deformation. Upper neck compression was -7,426 N in the production test; it was -8.339 N in the buck test and -7,549 N in the roll caged tests. The loads occurred at about 25 msec in all tests. Maximum roof/pillar deformation occurred 150 ms later in the production test.

Conclusion: Peak neck compressions were similar in the three tests and occurred shortly after initial head contact and prior to significant roof/pillar deformation. Neck injury responses resulted from torso augmentation and were independent of roof system deformation.
Electronically Controlled Brake System with Two-Channel Pressure Control for Electric Vehicles
Authors: Watanabe Shunya , Yamamoto Takayuki , Masuda Yoshio , Yamakita Hiroki
Published: April 2023

In this study, we introduce an electronically controlled brake system (ECB) that can be applied to electric vehicles (EVs) and internal combustion engine vehicles (ICEVs). The main features of the ECB include maximizing the regenerative energy while maintaining vehicle stability and ensuring redundancy in automatic braking. The brake system consists of upper and lower units. The newly developed upper unit has a brake-by-wire configuration and can control the front and rear wheel pressures separately. Hereinafter, controlling the front and rear wheel pressures separately is referred to as two-channel pressure control. The regenerated energy can be maximized while appropriately maintaining the distribution of the front and rear braking forces based on the two-channel pressure control during regenerative cooperation. The lower unit is a conventional hydraulic unit for executing anti-lock brake control, electronic stability control and so on. Each of the upper and lower units has a pressure source and is connected via a communication bus. Thus, even if one of the pressure sources malfunctions during automatic braking, sufficient brake forces can be ensured by another brake system.
Road Parameter Estimation with Drone-Vehicle Communication
Authors: Beliautsou Viktar , Beliautsou Aleksandra , Ivanov Valentin
Published: April 2023

The presented study is dedicated to the technology supporting vehicle state estimation and motion control with a concept drone, which helps the vehicle in sensing the surroundings and driving conditions. This concept allows also extending the functionality of the sensors mounted on the vehicle by replacing or including additional parameter observation channels.

The paper discusses the feasibility of such a drone-vehicle interaction as well as demonstrates several design configurations. In this regard, the paper presents a general description of the proposed drone system that assists the vehicle and describes an experiment in measuring the profile of the road with a range sensor. The results obtained in the experiment are described in terms of the accuracy to be achieved using the drone and are compared with other studies, which use the methods of estimation from the sensors mounted on the vehicle.

The proposed measurement concept can be applied to a large number of vehicle systems such as adaptive cruise control, active or semi-active suspension, and wheel slip control. The road profile is captured in real-time by a drone, and the telemetry data is processed by the host computer.
Vehicle Dynamics Modeling of Commercial Vehicle Steer Axle Tire Disablements at Highway Speeds
Authors: Dunn Ashley L. , Timbario Thomas A.
Published: April 2023

There have been many studies regarding the stability of vehicles following a sudden air loss event in a tire. Previous works have included literature reviews, full-scale vehicle testing, and computer modeling analyses. Some works have validated physics-based computer vehicle simulation models for passenger vehicles and other works have validated models for heavy commercial vehicles. This work describes a study wherein a validated vehicle dynamics computer model has been applied to extrapolate results to higher event speeds that are consistent with travel speeds on contemporary North American highways. This work applies previously validated vehicle dynamics models to study the stability of a five-axle commercial tractor-semitrailer vehicle following a sudden air loss event for a steer axle tire. Further, the work endeavors to understand the analytical tire model for tires that experience a sudden air loss. The studies discussed include executing physics-based vehicle dynamics models at speeds ranging from 88.5 kilometers per hour (55 miles per hour) up to 125.5 kilometers per hour (78 miles per hour), at various vehicle loading conditions and differing levels of velocity-dependent rolling resistance. The effects of speed and payload on vehicle response are analyzed and discussed.

For all the simulations in this study, a left steer axle tire sudden deflation was modeled. The results of the work revealed that after a modeled sudden air loss event, a manageable steering wheel angle would have to be input into the tractor steering system to arrest the initial yaw to the left caused by unbalanced longitudinal forces on the steer axle. The resultant initial corrective steer angle was found to be consistent with testing results and was in the range of 36 to 59 degrees steering wheel angle (SWA). As control of the tractor-semitrailer is maintained, the steering wheel angle required to hold the vehicle in a lane, steady-state, was found to be in the range of 24 to 38 degrees SWA.