The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

Reaction and response times
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Dynamic behavior of in-cylinder pressure causing fatigue failure of reed valves

Subros Ltd.-Ankit Shukla, Paulson Parayil, Arun Kumar Goel, Kamal Sharma
  • Technical Paper
  • 2020-28-0031
To be published on 2020-04-30 by SAE International in United States
For years, researchers have presented numerous studies that consider interaction between working fluid and reed valve motion in displacement compressors. The computing capacities and available CFD and FEA simulation tools have allowed modeling of fully coupled interaction of fluids and moving structures. The present paper describes our experience and results from developing a simplified model of a multi-cylinder reciprocating piston compressor and estimation of pressure surge during sudden acceleration of such compressors. The results show that sudden speed change causes surge in pressures due to formation of pressure waves that reflect back and forth within cylinder. For the chosen geometry and operating conditions, the duration of such waves is much shorter (~ 0.2ms) as compared to longer response time of reed valves (1 ms) that are stiff and highly inelastic. These high pressure waves eventually exceed the fatigue limit of reed valves and cause failures. These pressure waves also influence the performance of reciprocating by causing noise and vibrations which eventually dissipate in to heat thereby lowering the COP of compressor. Simulation results compare well…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Investigation on Safety Improvements by Lighting for Pedestrians and Cyclists

Audi AG-Michael Hamm, Christian Hinterwaelder
  • Technical Paper
  • 2020-01-0633
To be published on 2020-04-14 by SAE International in United States
The paper will describe actual investigations on safety improvements by new lighting functions. Especially the new chance of projections on the road surface either by simple reflector technology or by modern signature and pattern projection will be investigated. Several different prototype technology will be checked by a set of new parameters, e.g. reaction time to signals, clear understanding, minimum and optimum visual contrasts etc.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Multi-objective Optimization of Response Characteristics for High Power Common Rail Injector

China Shipbuilding Power Institute Co., Ltd.-Lizhou Fu
Harbin Engineering University-Qi Lan, Yun Bai, Liyun Fan, Jing Xu, Yuanqi Gu
  • Technical Paper
  • 2020-01-0833
To be published on 2020-04-14 by SAE International in United States
High pressure common rail system (HRCRS) is regarded as the most promising fuel injection system. As the key element of the HPCRS, the performance of the electronically controlled common rail injector (ECCRI) determines the working ability of the diesel engines. Excellent response characteristics is an important guarantee for the ECCRI to realize ideal injection rate, which means a lot to the injection characteristics and combustion quality for the diesel engines. In an effort to investigate the response characteristics of the ECCRI, an AMESim simulation model for high power ECCRI was presented in this article. And 8 crucial structure parameters about the response characteristics were selected as the research factors. Based on Central Composite Design of Experiment and Response Surface Method, the prediction models between the opening response time (ORT) and the closing response time (CRT) of the ECCRI and the crucial parameters were established. And the optimization solution sets (Pareto frontier) of the ORT and the CRT were obtained through Genetic Algorithm. The structure parameters corresponding to the point closest to the origin on the…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Driver Perception of Lateral Collision Threats

30 Forensic Engineering-Fabian Erazo, Adam Campbell
  • Technical Paper
  • 2020-01-1198
To be published on 2020-04-14 by SAE International in United States
Immediate collision hazards pose obvious threats to approaching drivers and therefore provoke emergency evasive responses. When the hazard is a vehicle intruding into the lane ahead, how its movement characteristics influence and approaching driver’s response is not well understood.This study examined the relationship between intruding vehicle motion and hazard perception. Seventeen subjects viewed first-person perspective recordings of a simulated vehicle travelling down a two-lane roadway containing several intersections with stop-controlled minor roads. Stopped vehicles were located at approximately half of the minor road intersections. Throughout the study, some vehicles (termed ‘intruders’) accelerated into the subject’s lane of travel at 1 of 6 pre-determined acceleration rates. Subjects were instructed to ‘brake’ their vehicle by pressing the space bar on a keyboard as soon as they perceived that a collision was imminent. Perception and response times (PRT) were measured as the elapsed time between the intruder’s first motion and braking. The duration of the perception interval was subsequently estimated by deducting a simple reaction time interval from the total PRT.The results indicated a significant relationship between perception…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Driver response to right turning path intrusions at signal-controlled intersections

Kodsi Engineering-Shady Attalla, Sam Kodsi
University of Guelph-Erika Ziraldo, Michele Oliver
  • Technical Paper
  • 2020-01-0884
To be published on 2020-04-14 by SAE International in United States
Previously researched path intrusion scenarios include left turning hazard vehicles which intrude laterally across the path of the through driver. A right turning vehicle, however, creates a scenario where a hazard which was initially traveling perpendicular to the driver can intrude into the through driver's path without also occupying the adjacent through lanes. This hazard scenario has not been previously investigated. The purpose of this research was to determine driver response time (DRT) and response choice to a right turning vehicle that merges abruptly into the lane of the oncoming through driver. A study was conducted using an Oktal full car driving simulator. 107 licenced drivers (NFemale=57, NMale=50) completed a short practice drive followed by an experimental drive containing two conditions of the right turn hazard, presented in a counterbalanced order. In one condition, the hazard vehicle was stopped at the stop bar before accelerating into the path of the participant driver. In the other condition, the hazard vehicle approached the intersection and turned at a constant speed. DRT was defined as the time between…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Driver response to left incurring path intrusions at sign-controlled intersections

Kodsi Engineering-Shady Attalla, Sam Kodsi
University of Guelph-Erika Ziraldo, Michele Oliver
  • Technical Paper
  • 2020-01-0886
To be published on 2020-04-14 by SAE International in United States
Straight intersecting path or “side” collisions account for 12% of all motor vehicle crashes and 24% of fatalities. While previous research has examined driver responses to hazards striking from the right (near side), no research has quantified driver responses to hazards striking from the left (far side) of an intersection. The purpose of this study was to measure driver response time (DRT) and response choice for two versions of this scenario. In one condition, the hazard vehicle was initially stopped at the intersection before accelerating into the path of the participant driver. In the other condition, the hazard vehicle approached and entered the intersection while moving at a constant speed of 50km/h. Testing was conducted using an Oktal full car driving simulator. 107 licenced drivers (NFemale=57, NMale=50) completed a short familiarization drive followed by the experimental drive in which they encountered both the initially stopped and moving conditions of the straight path hazard, in a counterbalanced order. DRT was defined as the time between when the hazard vehicle crossed a trigger located two meters from…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Fuel Tank Dynamic Strain Measurement Using Computer Vision Analysis

Ford Motor Company-Ram Krishnaswami
Fusion Engineering-Mark Fleming, Kunihiro Nakamoto
  • Technical Paper
  • 2020-01-0924
To be published on 2020-04-14 by SAE International in United States
Stress and strain measurement of high density polyethylene (HDPE) fuel tanks under dynamic loading is challenging. Motion tracking combined with computer vision was employed to evaluate the strain in an HDPE fuel tank being dynamically loaded with a crash pulse. Traditional testing methods such as strain gages are limited to the small strain elastic region and HDPE testing may exceed the range of the strain gage. In addition, strain gages are limited to a localized area and are not able to measure the deformation and strain across a discontinuity such as a pinch seam. Other methods such as shape tape may not have the response time needed for a dynamic event. Motion tracking data analysis was performed by tracking the motion of specified points on a fuel tank during a dynamic test. An HDPE fuel tank was mounted to a vehicle section and a sled test was performed using a Seattle sled to simulate a high deltaV crash. Multiple target markers were placed on the fuel tank. The motion of these markers was captured using…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Lookie Here! Designing Directional User Indicators Across Displays in Conditional Autonomous Vehicles

Georgia Institute of Technology-Wei Wang, Hongnan Lin
Harman Connected Services-Pranav Nair
  • Technical Paper
  • 2020-01-1201
To be published on 2020-04-14 by SAE International in United States
Based on the SAE’s classification (J3016), drivers’ attention will be gradually released from the driving task as the level of automation in the vehicle increases. It allows drivers to complete more non-driving related tasks in information and entertainment system. The trigger point for the major transition in driver control happens in the progression from level 2 to level 3 when the automated driving system (ADS) starts to perform a major part of the dynamic driving task (DDT) in the allowed conditions, but meanwhile it still needs the drivers are ready for takeover control or other interventions in a short time. In this paper, we investigated whether providing directional alerts to a user’s active screen with non-driving related tasks can augment their ability in regaining situational awareness on road hazard when traveling in a conditional autonomous vehicle. A user study (N=15) was conducted to compare solutions between the central and peripheral field across displays where subjects were seated in an autonomous vehicle simulator and distracted by playing a game on a tablet screen (iPad). With different…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Leverage wireless technologies in timber harvesting to enhance operational productivity and business profitability

John Deere-Ishani Pandit, Suchitra Iyer
  • Technical Paper
  • 2020-01-1378
To be published on 2020-04-14 by SAE International in United States
Growing needs of forestry products; primarily wood followed by pulp and paper industry have mechanized the process of harvesting timber in most part of world. Such job sites have several machines and vehicles working together to harvest and transport the logs. Timber logging is very similar to crop harvesting with longer harvesting cycle and hence it is critical that every part of it is effectively utilized; timely harvest and transport to factories play an important role. Traditionally, these areas have had little cellular connectivity, restricting communication between operators, machines, land owners and factories. With better connectivity, it will be easier to monitor and operate job sites for example if skidder would know how many trees are felled, how many logs and bunches are created and where they are kept; it would reduce time and fuel spent in searching for logs. Also, with better communication between machines, skidder would know when to pick up logs and avoid longer wait time. Timely pick up of felled trees is critical in ensuring log quality. With upcoming wireless technologies…
new

The Effect of An Acoustic Startling Warning On Take-Over Reaction Time And Trunk Kinematics for Drivers in Autonomous Driving Scenarios

Center for Injury Research and Prevention, Children’s Hospit-Valentina Graci, Madeline Griffith, Jalaj Maheshwari, Rahul Akkem, Meta Austin, Thomas Seacrist, Kristy B. Arbogast
  • Technical Paper
  • 2019-22-0022
Published 2020-03-31 by The Stapp Association in United States
The Acoustic Startling Pre-stimulus (ASPS, i.e. a loud sound preceding a physical perturbation) was previously found to accelerate action execution in simple flexion exercises. Therefore in this study we examined if ASPS can accelerate take-over reaction times in restrained teen and adult drivers who were asked to reach for the steering wheel while experiencing sled lateral perturbations simulating a vehicle swerve. Results showed that adult drivers lift their hands toward the steering wheel faster with the ASPS versus without (161 ± 23 ms vs 216 ± 27 ms, p<0.003). However this effect was not found in teens or in trials where the drivers were engaged in a secondary task. Adults also showed reduced lateral trunk displacement out of the seat belt with the ASPS. The ASPS could represent a novel warning that reduces take over time and out-of-position movements in critical autonomous driving scenarios.