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Innovative Rear Air Blower Design Application for Improving Cabin Thermal Comfort with improved Air Distribution and Air Quality.

Subros Ltd-Ravi Garg, Suraj maske, Yogendra Singh Kushwah
  • Technical Paper
  • 2020-28-0034
To be published on 2020-04-30 by SAE International in United States
In recent times, overall thermal comfort and air quality requirement have increased for vehicle cabin by multifold. To achieve increased thermal comfort requirements, multiple design innovation has happened to improve HVAC performance. Most of the advance and add on features like Multizone HVAC, dedicated rear HVAC, Automatic climate control, Advance Air filters, and Ionizers etc lead to increase in cost, power consumption, weight, and integration issues. Besides this in the vehicle with only front HVAC, airflow is not enough to meet rear side comfort for many cars in the B/C/SUV segment. This study aims to analyze the various parameters responsible for human thermal comfort inside a car with the focus on lightweight, low power consumption, compact Rear Blower to make passengers more comfortable by providing optimum airflow inline of mean radiant temperatures and cabin air temperature. The new design of Rear blower external surfaces has a set of air modifier surfaces in the direction of flow outlet. The second set of air modifier surfaces & an air deflator portion provided just upstream of outlet portion.…
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Heavy Vehicles Kinematics of Automatic Emergency Braking Test Track Scenarios

NHTSA-Devin Elsasser
Transportation Research Center Inc.-M. Kamel Salaani, Christopher Boday
  • Technical Paper
  • 2020-01-0995
To be published on 2020-04-14 by SAE International in United States
This paper presents the test track scenario design and analysis used to estimate the performances of heavy vehicles equipped with forward collision warning and automatic emergency braking systems in rear-end crash scenarios. The first part of this design and analysis study was to develop parameters for brake inputs in test track scenarios simulating a driver that has insufficiently applied the brakes to avoid a rear-end collision. In the second part of this study, the deceleration limits imposed by heavy vehicles mechanics and brake systems are used to estimate automatic emergency braking performance benefits with respect to minimum stopping distance requirements set by Federal Motor Vehicle Safety Standards. The results of this study were used to complete the test track procedures and show that all heavy vehicles meeting regulatory stopping distance requirements have the braking capacity to demonstrate rear-end crash avoidance improvements in the developed tests.
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The Effect of Crash Severity and Structural Intrusion on ATD Responses in Rear-End Crashes

Exponent Inc.-Chantal Parenteau, Jeffrey Croteau, John Zolock
  • Technical Paper
  • 2020-01-1224
To be published on 2020-04-14 by SAE International in United States
This study assesses vehicle and occupant responses in six vehicle-to-vehicle high-speed rear impact crash tests conducted at the Exponent Test and Engineering Center. The struck vehicle delta Vs ranged from 32 to 76 km/h and the vehicle centerline offsets varied from 5.7 to 114 cm.Five of the six tests were conducted with Hybrid III ATDs (Anthropometric Test Device) with two tests using the 50th male belted in the driver seat, one test with an unbelted 50th male in the driver seat, one test with a 95th male belted in the driver seat, and one with the 5th female lap belted in the left rear seat. All tests included vehicle instrumentation and three tests included ATD instrumentation. The ATD responses were analyzed and compared to corresponding IARVs (injury assessment reference values). Ground-based and onboard vehicle videos were synchronized with the vehicle kinematic data and biomechanical responses.The timing of the vehicle crush, occupant compartment intrusion, seatback motion, and ATD kinematics were assessed. The results indicated that the rear structures of the struck vehicle were significantly crushed by…
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Low-Energy Seat Compression: Characterizing Stiffness in Different Vehicles

Guidance Engineering-Bethany L. Suderman, Denise R. Cruise, Nicholas H. Yang, Edmund Lau, Lenka Stepan, Irving Scher
  • Technical Paper
  • 2020-01-0527
To be published on 2020-04-14 by SAE International in United States
In rear-end collisions, occupants move rearward relative to the vehicle interior, while compressing the seatback. In low-energy impacts, the stiffness of the non-frame seat components may influence the kinematic response of an occupant. Previous research has reported seat stiffness from experiments for a limited number of seats. Because passenger vehicle seats have evolved, this current work reports a range of seat stiffnesses for modern passenger vehicles. A portable measuring device to characterize vehicle seat stiffness was built to accommodate a wide range of vehicle types. The device measured simultaneously the force applied to the seat and the displacement of the seat cushion. Seats of sedans, crossovers, sport utility vehicles, minivans, and pickup trucks for model years between 2016 and 2020 were tested using the device. For each seat, three measurements were taken for four different seat regions: upper seatback, lower seatback, aft seat bottom and fore seat bottom. The seat stiffness for each region was determined using a linear fit of the force-displacement curve generated during testing. The range of seat stiffness across all seat…
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The Effect of FMVSS 301R on Vehicle Structure in Rear Impact

Collision Research & Analysis Inc.-Gregory Stephens
Exponent Inc.-Chantal Parenteau, Jennifer Yaek, Serge Gregory
  • Technical Paper
  • 2020-01-1226
To be published on 2020-04-14 by SAE International in United States
Vehicle structures are designed to manage impact forces and transfer crash energy. With the introduction of new rear impact requirements, the design of rear structures has evolved and the use of high strength steel has increased. This study objective was to assess the effect of new FMVSS 301 requirements on vehicle responses. NHTSA conducted 33 offset rear crash tests at 80 km/h with vehicles that pre-dated the newer FMVSS 301R requirements and 86 with vehicles that complied with the newer requirements, with a 2009-2015 model year range. The vehicles were grouped by size and the crush was tabulated. Overall, the struck-side maximum crush decreased in the newer model vehicles. Seven matches with pre and post 301R were identified based on make and model. The matched tests were reconstructed using video analysis and crush measurements of both the barrier and vehicle. Generalized vehicle stiffness was determined for each of the matched tests and indicated that vehicles generally became stiffer with new 301R requirements. The average stiffness was about two-times greater in the post-301R models than in…
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Methods for quantifying the impact severity of low-speed side impacts at varying angles

American Bio Engineers-Justin Brink, Scott Swinford, Brian Jones
Biomechanical Research & Testing-Christopher Furbish, Judson Welcher
  • Technical Paper
  • 2020-01-0641
To be published on 2020-04-14 by SAE International in United States
Accurately quantifying the severity of minor vehicle-to-vehicle impacts has commonly been achieved by utilizing the Momentum Energy Restitution (MER) method. A review of the scientific literature revealed investigations assessing the efficacy of the MER method primarily for: 1) inline rear-end impacts, 2) offset rear-end impacts, and 3) side impacts configured with the bullet vehicle striking the target vehicle at an approximate 90° angle. To date, the utility of the MER method has not been examined and readily published for quantifying oblique side impacts. The aim of the current study was to observe the effectiveness of the MER method for predicting the severity of side impacts at varying angles. Data were collected over a sequence of 12 tests with bullet-to-target-vehicle contact angles ranging from approximately 45° to 135° with corresponding impact speeds of approximately 13.7 km/h to 16.4 km/h. Vehicle damage profiles documented after each test allowed for the application of the MER method to calculate the target vehicle’s change in velocity (ΔV). Calculated ΔV’s were then compared to the vehicle’s recorded change in velocity obtained…
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Occupant Dynamics during Moderate-to-High Speed Rear-End Collisions

Vollmer-Gray Engineering Laboratories-Mohammad Atarod
  • Technical Paper
  • 2020-01-0516
To be published on 2020-04-14 by SAE International in United States
Numerous studies have evaluated occupant kinematics and dynamics in “low-speed” rear-end impacts (delta-V ≤ 8 mph). Occupant biomechanics during “moderate-to-high” speed rear impacts (9 ≤ delta-V ≤ 20 mph) has not been thoroughly examined. This study characterized the motions and forces experienced by the head, neck, torso, hip, and left/right femur during these collisions. The publicly available NHTSA rear-end crash test data were examined. More specifically, the FMVSS 301 Fuel System Integrity tests were used. The test procedure involved a 30 mph moving barrier impacting the rear of the vehicles. Instrumented 50th-percentile male (N = 47) or 5th-percentile female (N = 4) Hybrid III ATDs were positioned in the driver seat. Occupant data including head accelerations, upper/lower neck shear and axial forces, upper/lower neck moments, lower neck acceleration, torso accelerations, torso deflection, hip accelerations, and left/right femur axial forces were evaluated and compared to published injury tolerance data. The vehicle accelerations, vehicle delta-Vs, occupant position data, seat angular velocity, seat rotation and seatbelt forces and pullout were also examined. Target vehicle peak accelerations were 22.9…
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Update on Second-Row Children Responses in Rear and Frontal Crashes with a Focus on the Potential Effect of Stiffening Front Seat Structures

Exponent Inc.-Chantal Parenteau
ProBiomechanics LLC-David Viano
  • Technical Paper
  • 2020-01-1215
To be published on 2020-04-14 by SAE International in United States
NHTSA has recently been petitioned to address the protection of second-row children in rear crashes due front seatback performance. The protection of children is important. However, it is more complex than assessing front seat performance in rear impacts. Viano, Parenteau (2008 [1]) analyzed cases of serious-to-fatally injured (MAIS 3+F) children up to 7 years old in the second row in rear impacts involving 1990+ model year vehicles using 1997-2005 NASS-CDS. They observed that intrusion was an important factor pushing the child forward into the back of the front seat, B-pillar or other front structure.To help assess whether stiffening the front seats would be beneficial for second-row child safety, the 2008 study was updated using more recent data and model year vehicles. In the present study, 1997-2015 NASS-CDS data were analyzed for serious-to-fatally (MAIS 3+F) injured 0- to 7-year old children in the second row with 1994+ model year vehicles. First, the data were analyzed to estimate the distribution and risk of serious-to-fatally (MAIS 3+F) injured children by crash types. The results showed that the greatest…
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The Effect of Changing Vehicle Seat Stiffness: A MADYMO Sensitivity Analysis

Guidance Engineering-Denise R. Cruise, Bethany L. Suderman, Nicholas H. Yang, Lenka Stepan, Irving S. Scher
  • Technical Paper
  • 2020-01-0524
To be published on 2020-04-14 by SAE International in United States
In low-speed, rear-end collisions, the occupant in the target vehicle moves rearward relative to the vehicle and interacts with the seatback and seat bottom. Due to the direct interaction of the occupant with the seat, seat stiffness can affect the kinematics of the occupant. Generic seat stiffness values are often used as input parameters in computer programs, such as MADYMO, that are used to model low-speed, rear-end collisions and simulate occupant kinematics. To create an accident specific simulation, the model could take into account all aspects of the accident including the person involved, the subject vehicle, and the subject vehicle seat. Recent research has demonstrated that the seat stiffness of the compressible structure of the seat, comprised of foam and springs, can vary between vehicles, and also can vary between regions within a single vehicle seat. In order to examine the influence of seat stiffness on occupant kinematics and internal loads, MADYMO simulations were performed with a 50th percentile male Human Body Model (HBM) for a single accident sequence using seat stiffness values obtained from…
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Injury Rates by Crash Severity, Belt Use and Head Restraint Type and Performance in Rear Impacts

Exponent Inc.-Chantal Parenteau, Bruce Miller
Ford Motor Company-Roger Burnett
  • Technical Paper
  • 2020-01-1223
To be published on 2020-04-14 by SAE International in United States
This study assesses the exposure distribution and injury rate (MAIS 4+F) to front-outboard non-ejected occupants by crash severity, belt use and head restraint type and damage in rear impacts using 1997-2015 NASS-CDS data. Rear crashes with a delta V <24 km/h (15 mph) accounted for 71% of all exposed occupants. The rate of MAIS 4+F increased with delta V and was higher for unbelted than belted occupants with a rate of 11.7% ± 5.2% and 6.0% ± 1.5% respectively in 48+ km/h (30 mph) delta V. Approximately 12% of front-outboard occupants were in seats equipped with an integral head restraint and 86% were with an adjustable head restraint, irrespective of crash severity. The overall injury rate was 0.14% ± 0.05% and 0.22% ± 0.06%, respectively. It was higher in cases where the head restraint was listed as “damaged”. Thirteen cases involving a lap-shoulder belted occupant in a front-outboard seat in which “damage” to the adjustable head restraint was identified. Review of these cases showed that intrusion and crash severity were important factors and that the…