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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.

Control-Oriented Modeling of a Vehicle Drivetrain for Shuffle and Clunk Mitigation

Ford Research & Advanced Engineering-Maruthi Ravichandran, Mary Farmer, Jeff Doering
Michigan Technological Univ.-Prithvi Reddy, Kaushal Darokar, Darrell Robinette, Mahdi Shahbakhti, Jason Blough
  • Technical Paper
  • 2019-01-0345
To be published on 2019-04-02 by SAE International in United States
Flexibility and backlash of vehicle drivelines typically cause unwanted oscillations and noise, known as shuffle and clunk, during tip-in and tip-out events. Computationally efficient and accurate driveline models are necessary for the design and evaluation of torque shaping strategies to mitigate this shuffle and clunk. To accomplish these goals, this paper develops two control-oriented models, i.e., a full-order physics-based model and a reduced-order model, which capture the main dynamics that influence the shuffle and clunk phenomena. The full-order model comprises several components, including the engine as a torque generator, backlash elements as discontinuities, and propeller and axle shafts as compliant elements. This model is experimentally validated using the data collected from a Ford truck. The validation results indicate less than 1% error between the model and measured shuffle oscillation frequencies. The reduced-order model is derived by lumping 24 inertia elements into 2 elements, 4 stiffness and damping elements into 2 elements, and 2 backlashes into 1 element. As part of the reduced-order model development, the paper investigates: (i) the effect of lumping transmission and final…

Methodology of Roller Bearing’s Preload Setting and Physical Verification of Axle in Tipper Application.

VE commercial Ltd-Jeevan Ramesh Jathar
  • Technical Paper
  • 2019-01-1297
To be published on 2019-04-02 by SAE International in United States
The roller bearings and their performance is basic factor to uniqueness of transmission life, in automobile car, trucks as well as in tipper also. Transmission use helical gearing and taper roller bearings. The Continues running with heavy loads will deteriorate the performance of vehicle mainly due to bearing failures, that phenomenon happens because of improper alignment on shaft and wrong setting of preloading. The life of bearings L10 (Hrs) confirmed by setting of bearing preload (50 ~ 100 microns) through shim selection in accordance with the tolerance stack methodology. The bearings itself have radial as well as linear clearance depends on size and its application, while running of vehicle ( Dynamic Condition) bearings are taking all degrees of torque reactions and full-fill the transmission purpose, due to continuous high level of vibration through driveline and from power train , bearing sleeve loosening effects carry over there and deteriorate transmission performance, avoid such situation bearing’s clearances are optimized in accordance with consideration of application, load, temperature and fit called as preload. By this approach bearings are…

Evaluating a Heavy-duty Truck Climate Control System using Thermal Comfort-focused Testing and Simulation Techniques

ThermoAnalytics Inc.-Mark Hepokoski, Steven Patterson, Allen Curran
Volvo Trucks North America-Steven Adelman, Miguel Javier
  • Technical Paper
  • 2019-01-0696
To be published on 2019-04-02 by SAE International in United States
The design of efficient vehicle climate control systems involves reconciling two competing objectives: Maximizing the thermal comfort of occupants while simultaneously reducing the vehicle’s energy usage. Given the energy expenditure of traditional HVAC systems, efforts have been directed toward reducing their weight and power requirements. Consequently, vehicle manufacturers are increasingly investigating the use of thermal comfort as a design metric, rather than air temperature, which requires heating or cooling of the entire cabin air volume. Thermal comfort-focused technologies, such as localized heating and cooling strategies, have the potential to elicit favourable subjective responses to thermal environments even when the ambient air temperature in the cabin would otherwise fall outside of established acceptability guidelines. These technologies can be especially relevant for heavy-duty truck manufacturers since the cabin is relatively large, with an HVAC system sized accordingly, and often occupied by a single driver for long durations. Thermal comfort-focused testing and simulation techniques previously employed for automobiles have been applied to scenarios involving heavy-duty trucks. A set of human subjects and a test system comprised of a…

Modeling of Engine After Treatment System Cooling for Hybrid Vehicles

Linkoping Univ-Lars Eriksson
Linköping Univ.-Olov Holmer
  • Technical Paper
  • 2019-01-0989
To be published on 2019-04-02 by SAE International in United States
The medium and heavy duty transport industry is currently showing a growing interest in hybrid powertrains. Currently, this technology is mainly used in buses but distribution trucks, both heavy and medium duty, are expected to become growing market segments. Hybrid trucks are potentially superior to conventional internal combustion engine (ICE) propelled trucks in a wide range of environmental areas like noise, CO2 and NOx emissions. However, since the hybrid vehicle is still partially powered by an ICE, an engine after treatment system (EATS) is necessary. Traditionally, the EATS is heated by the waste heat entering the tail pipe after the turbo. This is the most fuel efficient and practical way of bringing the EATS up to and maintaining operating temperatures of about 200 - 400 ̊C, where it's most efficient. However, in hybrid vehicles the ICE can be shut off to a larger extent than in conventional vehicles, and when the engine is off the EATS cools down. Eventually the EATS will drop below the desired temperature range making the EATS ineffective when the ICE…

A generalized component efficiency and input-data generation model for creating fleet-representative vehicle simulation cases in VECTO

Aristotle University of Thessaloniki-Nikiforos Zacharof
European Commission Joint Research-Alessandro Tansini, Theodoros Grigoratos, Georgios Fontaras
  • Technical Paper
  • 2019-01-1280
To be published on 2019-04-02 by SAE International in United States
Heavy-duty vehicles (HDV) account for 4% of the European vehicle fleet, but they are responsible for the 30% of the European Union’s road CO2 emissions. The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and monitoring of CO2 emissions of HDVs in Europe. The tool uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. However, such data are confidential and are not disclosed. For this reason, any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require "generic" inputs or reconstructing realistic component input data. The current study attempts to address this issue. The study aimed to develop a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency, e.g. gearbox and axle efficiency maps and produce the necessary VECTO input data. The target groups were the regulated HDV Classes, and within this…

A method for calculating Heavy-Duty Trucks energy and fuel consumption with the use of correlation formulas derived from VECTO simulations

Aristotle University of Thessaloniki-Nikiforos Zacharof
European Commission Joint Research-Alessandro Tansini, Georgios Fontaras, Biagio Ciuffo
  • Technical Paper
  • 2019-01-1278
To be published on 2019-04-02 by SAE International in United States
The Vehicle Energy Consumption calculation Tool (VECTO) is used in Europe for calculating standardised energy consumption and CO2 emissions from Heavy-Duty Vehicles (HDVs) for certification purposes. The tool requires detailed vehicle technical specifications and a series of component efficiency maps. In the context of quantifying HDV CO2 emissions, the Joint Research Centre (JRC) of the European Commission collected simulation data about the 2016 vehicle fleet. The simulation data were initially normalised to compensate for differences and issues in the quality of the input data used to run the simulations. Secondly, the data received were used to understand the factors contributing to the energy consumption. Correlation formulas were produced to calculate individual energy loss contributions (air drag, rolling resistance, axle and gearbox losses) over the regional delivery and long-haul cycles, given few input parameters such as vehicle characteristics and average component efficiencies. Default values and meaningful ranges of variation of these parameters were derived from the fleet data and are reported in the paper. The importance of air drag and rolling resistance losses is presented, which…

Numerical Investigation of Wiper Drawback

Dassault Systemes-Jonathan Jilesen
Exa Corporation-Tom Linden
  • Technical Paper
  • 2019-01-0640
To be published on 2019-04-02 by SAE International in United States
Windscreen wipers are an integral component of the windscreen cleaning systems of most vehicles, trains, cars, trucks, boats and some planes. Wipers are used to clear rain, snow, and dirt from the windscreen pushing the water from the wiped surface. Under certain conditions however, water which has been pushed from the windscreen by the wiper can be pulled back on the windscreen by aerodynamic forces introduced by the wiper motion, wiper pull back. This is an undesirable phenomenon as the water which is pulled back on to the windscreen can reduce driver visibility and makes the wiper less effective. The phenomena of wiper pull back can be tested for in climatic tunnels using sprayer systems to wet the windscreen. However, these tests require a prototype vehicle, which means that the tests are done fairly late in the development of the vehicle. Furthermore, these results do not provide significant insight into the mechanisms driving the wiper pull back. In order to better understand wiper pull back a numerical simulation of a configuration known to exhibit wiper…

VirtualCrash.com - Occupant Crash Simulation Analysis Made Easy

Hork Enterprises-Henk B. Helleman
  • Technical Paper
  • 2019-01-1036
To be published on 2019-04-02 by SAE International in United States
Over 30 years of occupant crash safety simulations have seen ever more sophisticated tools and models to keep pace with ever more demanding and expanding requirements. These sophisticated tools, however, require highly trained and experienced analysis specialists to operate. This keeps them out of reach of occasional users such a program managers, restraints buyers, and design engineers. Yet, the people involved in the early stages of vehicle development can have a great impact on vehicle safety performance and the costs of achieving the targets. By combining prebuild models and a fully capable finite element solver with an easy to use web interface, we aim to make the simulation technology available to anybody with a web browser. The virtualcrash.com application is richly featured. Alike to sled testing, there is a choice of multiple vehicle geometries, from sub-compacts to large trucks. They come with crash pulses that are typical for their class that may be scaled up or down to make them more or less severe. If that does not suit the purpose, a custom crash pulse…

SEMS for individual trip reports and long-time measurement

Horiba Europe GmbH-Frank Heepen, Weilin Yu PhD
  • Technical Paper
  • 2019-01-0752
To be published on 2019-04-02 by SAE International in United States
Abstract for WCX SAE World Congress Experience April 9-11, 2019 SEMS for individual trip reports and long-time measurement During the last decade the gap between real-world driving emissions and test-bench tests became obvious. To overcome this gap, all modern passenger cars and trucks in Europe must undergo an on-road driving emission test with portable emissions measurement systems (PEMS). The currently used PEMS however, have some constraints, due to the large volume and operation effort. PEMS are meant for monitoring the emissions of a vehicle for a limited time. To cover real-world driving conditions, a longer, more diverse measurement is desirable. To derive robust and reliable emission factors a simple and easy-to-use emission monitoring solution, the Smart Emission Measurement System (SEMS) was developed. Since 2012, this automotive sensor-based system and toolbox has been continuously developed and validated, through numerous measurements of emissions from light duty vehicles (LDV), heavy duty vehicles (HDV) and non-road mobile machinery (NRMM). HORIBA and TNO are collaborating on the industrialization and large-scale deployment of SEMS, enabling new possibilities for measuring real-world driving…