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Heavy-duty aerodynamic testing for CO2 certification: A methodology comparison

Intl. Council on Clean Transportation-J. Felipe Rodriguez, Oscar Delgado
University of Technology Graz-Martin Rexeis, Martin Röck
  • Technical Paper
  • 2019-01-0649
To be published on 2019-04-02 by SAE International in United States
Air drag testing is a key component of the CO2 certification schemes for heavy-duty vehicles around the world. This paper presents and compares the regulatory approaches for measuring the air drag coefficient of heavy-duty vehicles in Europe, which uses a constant-speed test, and in the United States and Canada, which use a coastdown test. Two European trucks and one North American truck were tested using the constant-speed and coastdown methods. When corrected to zero yaw angle, a difference of over 10% was observed in the measured drag coefficients from the US coastdown procedure and the EU constant-speed test. The differences in the measured air drag coefficient can be attributed to the data post-processing required by each methodology, the assumptions in the speed-dependence of the tire rolling resistance, unaccounted frictional losses in the differential axle and transmission, as well as the behavior of the automated manual transmission during the coastdown run.

Research on The Model of Safety Boundary Condition Based on Vehicle Intersection Conflict and Collision

Tongji University-Biao Wu, Xichan Zhu, Maozhu Liao, Rui Liu
  • Technical Paper
  • 2019-01-0132
To be published on 2019-04-02 by SAE International in United States
Because of the high frequency and serious consequences of traffic accidents in the intersection area, it is of great significance to study the vehicle conflict and collision scenarios of the intersection area. Due to few actual crash accidents occurring in naturalistic driving studies data or field operational tests data, the data of traffic accident database should be also used to analyze for the intersection conflict and collision study. According to the China Field Operation Test (China-FOT) database and the China in Depth Accident Study (CIDAS) database, the distribution feature of the respective intersection scenario type is obtained from the data analysis. Based on the intersection scenario type, two characters of intersection conflict and collision, that the environmental character and the vehicle dynamic character, are used to analyze for the integration process of intersection conflict and collision. The environmental character contains environment type, weather and time parameters, which has a strong influence on the collision accidents. During the environmental parameters analysis, the distribution model of environmental character is obtained. The vehicle dynamic character includes two vehicle…

CATARC New Type Drivetrain NVH Test Facility

CATARC-Hui Gao, Yongchao Wang, Dong Wang
Jilin University-HongBin Yin
  • Technical Paper
  • 2019-01-0788
To be published on 2019-04-02 by SAE International in United States
As the most intuitive performance of users, NVH performance is one of the comprehensive indicators to evaluate the manufacturing standard of the whole vehicle. About one-third of the vehicle complaint are related to NVH performance. As a core component of the vehicle, the NVH characteristics of the drivetrain have a significant impact on vehicle comfort . How to reliably and stably reproduce the specific condition of the whole vehicle through the test method, and obtain the highly consistent objective data for analyzing and improving the NVH characteristics of the drivetrain, which is of great significance in engineering. For this purpose, China Automotive Technology Research Center Co., Ltd. (CATARC) designed and built a unparalleled drivetrain NVH test facility, which consists of five dynamometers. Test specimens such as powertrain, transmission, and rear axle can be mounted to the facility. The structure is not limited to the horizontal/vertical, front/rear drive/four-wheel drive structure, or even a whole vehicle. Due to the battery simulator, the above specimens of the fuel vehicle, hybrid vehicle and electric vehicle can be satisfied. The…

Evaluation of Emissions from Light Duty Trucks with and without the Use of a Gasoline Particulate Filter

Environment and Climate Change Canada-Fadi Araji, Jonathan Stokes
  • Technical Paper
  • 2019-01-0971
To be published on 2019-04-02 by SAE International in United States
The goal of this study was to investigate the emission impacts of replacing the OEM three way catalyst on light duty trucks using various, commercially available, gasoline particulate filter (GPF) configurations. The three test vehicles were; a Port Fuel Injection (PFI) PFI_1 and two Gasoline Direct Injection (GDI) GDI_1 and GDI_2. The testing of these vehicles was conducted on a chassis dynamometer in a controlled test cell environment at two temperatures (25 °C and -7 °C) using the Federal Test Procedure (FTP-75) and the US06 test procedure. All three vehicles were tested in stock OEM configuration followed by testing PFI_1 and GDI_1 with a non-catalyzed GPF and GDI_2 with a catalyzed GPF. GDI_2 was also tested on-road using a portable emissions measurement system (PEMS) with and without the use of the catalyzed GPF. Results for the non-catalyzed GPF configuration on PFI_1 and GDI_1 showed a decrease in Total Particulate Matter (TPM) at both standard and cold temperatures, with the biggest decrease being 89.3% for GDI_1 during the FTP-75 at 25 °C. An increase in NOx…

Validation of Test Procedure for Measuring the Fuel Consumption of Production-Model FCVs

National Traffic Safety & Enviro Lab-Tetsuya Niikuni, Terunao Kawai
National Traffic Safety & Enviro Lab.-Kenichiroh KOSHIKA
  • Technical Paper
  • 2019-01-0382
To be published on 2019-04-02 by SAE International in United States
Factors affecting the measurement of the fuel consumption of FCVs were analyzed to reveal their sensitivity. The method for measuring fuel consumption described in the Worldwide harmonized Light vehicles Test Procedures (WLTP) is to measure the hydrogen consumption by using an electric precision balance and off-vehicle tanks (not on-vehicle tanks). This is unique compared with conventional vehicles such as petrol-engine vehicles and pure-electric vehicles. Therefore, we examined the sensitivities of the effect of hydrogen consumption determination, the effect of hydrogen supply pipe design, and the effect of hydrogen supply pipe management. The experiments were conducted with two production models of FCVs having different FC management systems. The effects were quantitatively evaluated by comparing the fuel consumption rate driving in the Worldwide Light-duty Test Cycles (WLTC). First, the hydrogen consumption amounts of the FCVs were measured with the gravimetric method. Then, a quantitative sensitivity analysis of the factors was conducted based on a hypothetical vehicle with a fuel consumption rate of 0.67 kg/100 km in the Low phase. All factors described in this paper were less…

Evaluation of Navigation in Mobile Robots for Long-Term Autonomy in Automotive Manufacturing Environments

Clemson University - ICAR-Jasprit Singh Gill, Mark Tomaszewski, Yunyi Jia, Pierluigi Pisu
  • Technical Paper
  • 2019-01-0505
To be published on 2019-04-02 by SAE International in United States
Thus far, the focus of autonomous mobile robot researchers has been primarily on developing the functionality and optimizing its performance. In recent times, a number of reference implementations of Simultaneous Localization and Mapping (SLAM) and navigation techniques have been made publicly available via the ROS Community. Several implementations have transitioned to commercial products (vacuum robots, drones, warehouse robots, etc.). However, in such cases, in being specialized and optimized for their specific domains of deployment, they became a “black box”. In particular, their success criteria have been based primarily on mission completion and safety of humans around them. In this light, deployment in any new operational design domain (ODD) requires at least a careful verification of performance and often re-optimization. We seek the technological gaps that need to be addressed to ensure the mobile robots are fit for automotive manufacturing environments. Automotive final assembly environments pose significant additional challenges for mobile robot deployment. They are replete with relatively unstructured tasks with significant uncertainty, involve tasks with skills that require robots to work in collaboration with humans…

On-Track Measurement of Road Load Changes in Two Close-Following Vehicles: Methods and Results

Argonne National Laboratory-Michael Duoba, Alejandro Fernandez Canosa
  • Technical Paper
  • 2019-01-0755
To be published on 2019-04-02 by SAE International in United States
As emerging automated vehicle technology is making advances in safety and reliability, engineers are also exploring improvements in energy efficiency with this new paradigm. Powertrain efficiency receives due attention, but also impactful is finding ways to reduce driving losses in coordinated-driving scenarios. Efforts focused on simulation to quantify road load improvements require a sufficient amount of background validation work to support them. This study uses a practical approach to directly quantify road load changes by testing the coordinated driving of two vehicles on a test track at various speeds (64, 88, 113 km//h) and vehicle time gaps (0.3 to 1.3 s). Axle torque sensors were used to directly measure the load required to maintain steady-state speeds while following a lead vehicle at various gap distances. Through trial and error, test methods were developed that appear to provide satisfactory results, considering the challenges of track testing under real-world conditions (wind, weather, temperature changes, etc.). We found that total road load was reduced by about 10–12% at an optimum gap time of 0.25 to 0.4 s. Challenges…

Research on Dynamic Load of Belgian Event Based on VPG

CATARC-Jiansen Yang, Xinyu Wang, xin li
  • Technical Paper
  • 2019-01-0170
To be published on 2019-04-02 by SAE International in United States
The durable load spectrum of the physical proving ground is the necessary input for fatigue life analysis of vehicle parts and components. It is usually obtained by vehicle road load acquisition and load decomposition in the industry, and Virtual Proving Ground (VPG) is gradually replacing this technical route. The belgian road is the typical event in durability test, in this paper, the flexible body and FTire model are applied to the multi-body dynamics model in order to improve the simulation accuracy. The result shows that all the wheel six-component force, shock absorber displacement and axial force acquired by VPG simulation have excellent correlation with real vehicle data. It is also proved that the virtual proving ground technology is a reliable and effective method to obtain the durable load spectrum in the early stage of development.

Experimental and Computational Study of the Flow around a Stationary and Rotating Isolated Wheel and the Influence of a Moving Ground Plane

Loughborough Univ-Duncan Walker
Loughborough Univ.-Eleanor Rajaratnam
  • Technical Paper
  • 2019-01-0647
To be published on 2019-04-02 by SAE International in United States
This study investigates the aerodynamic behaviour of the flow around a rotating and stationary 60% scale isolated wheel, without the use of a moving ground plane. The aim of this research was to further improve the understanding of the fundamental aerodynamic flow features and how wheel rotation and moving ground planes modify these. Wind tunnel tests were used to measure force coefficients and provide aerodynamic data through the use of Particle Image Velocimetry (PIV) and were performed over a range of pre to post critical Reynolds numbers, with the wheel driven by a rotating drum system. The experimental data was used to validate unsteady CFD calculations using STAR-CCM+. A K-Omega SST Improved Delayed Detached Eddy Simulation (IDDES) turbulence model was found to outperform other models by capturing an increased amount of finer detailed, high frequency vortical structures whilst also showing a good agreement with the experimental results. The CFD and experimental data illustrated large scale structural differences in the surrounding flow for both the stationary and rotating cases due to varying flow separations induced by…

On the Mechanical Design of the Rolling Road Addition to the CSUF Wind Tunnel

California State University, Fullerton-Ramitha Edirisinghe, Salvador Mayoral
  • Technical Paper
  • 2019-01-0651
To be published on 2019-04-02 by SAE International in United States
For ground effect aerodynamic studies in wind tunnels, boundary layer growth over the floor of the test section is a large concern. Many different techniques have been used to remove this boundary layer, of which creating a moving ground plane is considered the best option. By creating a moving floor in the test section, the ground plane speed can be set to that of the free stream air speed, thus removing the boundary layer or at the very least mitigating the boundary layer growth. Several studies detail the aerodynamic design concerns for such devices, but little information exists on the mechanical design concerns. This work reviews lessons learned during a design study of a rolling road for the wind tunnel at California State University, Fullerton (CSUF) mainly focusing on the motor specification and cooling system design. First, an overview of the major systems that comprise a rolling road apparatus are given. Then, initial constraints and free-body diagrams are presented detailing the forces experienced by the rolling road. From these free-body diagrams, analytical equations are presented…