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Technical Paper

A Philosophy of Full Vehicle Simulation for analysing the Road NVH Problems

Road and Engine borne noise are the most prominent sources of noise in any commercial vehicle. With advancement in technology and encouraging prospects in hybrid & electric vehicles, road noise can be set aside as the single most dominant source for vehicular NVH problems. In this paper, a full vehicle model is considered for complete NVH simulation with two acoustic and two structural response points. Random road excitations are applied at various vehicle speeds to determine the response characteristics. An elaborate study is conducted to understand the effects of vehicle speed and road conditions on the vehicle. An attempt is also successfully made to diagnose the effects of road excitations on the system behaviour by considering the suitable transfer functions. The methodology can be readily extended to any type of vehicle and speed as the excitations are independent of these parameters.
Technical Paper

Drivetrain Noise Source Identification and Active Noise Control of a Heavy Off-Road Vehicle

Drivetrain noise from heavy off-road vehicles mainly includes engine noise, drive shaft noise, wheel-side gear noise, tire pattern noise etc. They are the main noise sources for such vehicles as they greatly influence the ride comfort of the passengers inside. This paper solved the drivetrain noise problems of a heavy off-road vehicle using the method of active noise control (ANC). Firstly, the vehicle is benchmarked and the noise problems are analyzed, while the noise sources are identified by analyzing the transmission principles of the drivetrain. Secondly, ANC strategies are made for the vehicle based on the noise profiles under various operating conditions. Thirdly, the multiple parameters for ANC are computed from simulations modeling the vehicle in idle, constant speed and acceleration respectively. Lastly, road tests are conducted using the multiple parameters from the simulations and a noise reduction of 2-4 dB can be achieved in the whole vehicle.
Technical Paper

Optimizing Battery Cooling System for a Range Extended Electric Truck

Battery packs used in electrified automotive powertrains support heavy electrical loads resulting in significant heat generation within them. Cooling systems are used to regulate the battery pack temperatures, helping to slow down battery aging. Vehicle-level energy consumption simulations serve as a first step for determining the specifications of a battery cooling system based on the duty cycle and interactions with the rest of the powertrain. This paper presents the development of a battery model that takes into account the energy impact of heating in the battery and demonstrates its use in a vehicle-level energy consumption simulator to set the specifications of a suitable cooling system for a vehicle application. The vehicle application used in this paper is a Class 6 Pickup and Delivery commercial vehicle with a Range-Extended Electric Vehicle (REEV) powertrain configuration.
Technical Paper

Multi-Domain Optimization for Fuel Economy Improvement of HD Trucks

Fuel usage negatively impacts the environment and is a significant portion of operational costs of moving freight globally. Reducing fuel consumption is key to lessening environmental impacts and maximizing freight efficiency, thereby increasing the profit margin of logistic operators. In this paper, fuel economy improvements of a cab-over style 49T heavy duty Foton truck powered by a Cummins 12-liter engine are studied and systematically applied for the China market. Most fuel efficiency improvements are found within the vehicle design when compared to opportunities available at the engine level. Vehicle design (improved aerodynamics), component selection/matching (low rolling resistance tires), and powertrain electronic features integration (shift schedule/electronic trim) offer the largest opportunities for lowering fuel consumption.
Technical Paper

Pure Electric Vehicles Simulation Using Powertrain Energy Estimator Tool

This paper describes first, the use of Powertrain Energy Estimator (PEE) tool to simulate and analyze the performance of the Pure Electric Vehicles (PEV’s) with all the powertrain components. The PEE uses basic physics calculations and measured components performance with the available vehicle parameters to model and simulate any conceptual PEV. The tool calculates the predicted torques, speeds, voltages, efficiency and power passed from one component to another then saves all the simulation results in a database for further user’s analysis. Secondly, we present a methodology to estimate the maximum power capacity required for PEV driving electric machine (E-Motor). The estimation approach is based on creating a power map, which combines the contour lines for all power levels over vehicle speeds/road climbing grades required for the PEV powertrain driving component (E-Motor) to meet all the vehicle’s performance requirements.
Technical Paper

Integration of an ORC Waste Heat Recovery with Electrification and Supercharging through Use of a Planetary Gear System for a Class 8 Tractor Application

A novel approach to the Integration of Turbocompounding/WHR, Electrification and Supercharging technologies (ITES) to reduce fuel consumption in a medium heavy-duty diesel engine was previously published by FEV. This paper describes a modified approach to ITES to reduce fuel consumption on a heavy-duty diesel engine applied in a Class 8 tractor. The original implementation of the ITES incorporated a turbocompound turbine as the means for waste heat recovery. In this new approach, the turbocompound unit connected to the sun gear of the planetary gear set has been replaced by an organic Rankine cycle (ORC) turbine expander. The secondary compressor and the electric motor-generator are connected to the ring gear and the carrier gear respectively. The ITES unit is equipped with dry clutch and band brake allowing flexibility in mechanical and electrical integration of the ORC expander, secondary compressor and electric motor-generator to the engine.
Technical Paper

A Generalized Component Efficiency and Input-Data Generation Model for Creating Fleet-Representative Vehicle Simulation Cases in VECTO

The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. 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 by developing 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 maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10.
Technical Paper

Validating Heavy-Duty Vehicle Models Using a Platooning Scenario

Connectivity and automation provide the potential to use information about the environment and future driving to minimize energy consumption. Aerodynamic drag can also be reduced by close-gap platooning using information from vehicle-to-vehicle communications. In order to achieve these goals, the designers of control strategies need to simulate a wide range of driving situations in which vehicles interact with other vehicles and the infrastructure in a closed-loop fashion. RoadRunner is a new model-based system engineering platform based on Autonomie software, which can collectively provide the necessary tools to predict energy consumption for various driving decisions and scenarios such as car-following, free-flow, or eco-approach driving, and thereby can help in developing control algorithms.
Technical Paper

Modeling and Analysis of Clutch Engagement Judder in Commercial Vehicle Powertrain Systems

Transient events in a vehicle driveline such as tip in tip out, clutch engagement-disengagement, engine start, etc. are very important considering NVH characteristics and hence comfort of a vehicle system overall. Clutch engagement (especially during vehicle launch from a rest condition) is one of the most important transient events in commercial vehicles utilizing automated manual transmissions (AMTs). This paper presents common NVH issues observed during vehicle launch in a commercial heavy duty truck. One of the most important NVH issues is clutch engagement judder. Judder is seen when torque fluctuations are generated in a slipping clutch which induce undesired driveline vibrations. This paper concentrates on friction judder as well as geometric judder. Different friction materials are compared for their performance against friction judder. Performance of friction materials with respect to slip speed, temperature, and pressure is also studied.
Technical Paper

Modal Model Correlation of Commercial Vehicle Frame

Design decisions based on the virtual simulations leads to reduced number of prototype testing. Demonstrated correlation between the computer simulations and experimental test results is vital for designers to confidently take simulation driven design decisions. For the virtual design evaluation of durability, ride, handling and NVH performance, demonstration of correlation of structural dynamic characteristics is critical. Modal correlation between CAE and physical testing validates the stiffness and mass distribution used in the FE model by correlating mode shape and mode frequency in the desired frequency range. The objective of this study is to arrive at a method for establishing modal correlation between CAE and experimental test for a bare frame and thereby enabling evaluation of design iterations in virtual environment to achieve modal targets.
Technical Paper

Operational Deflection Shapes & Resonance Analysis Using Road Simulator

In today’s competitive world to stay in the commercial vehicle business, technological advancement is vital. Understanding the various operation modes of a vehicle considering the vibration becomes essential for developing a vehicle free from failures. ODS analysis is a method which is used to visualise the vibration pattern of a vehicle when influenced by known external operating forces. ODS provide very useful information for understanding and evaluating the behavior of the vehicle. This paper discusses about the experiments carried out in vehicle. It details the process of data collection at varying frequency input, understanding the modes at various frequencies, identifying the resonant frequency of various components, understanding the comparison between road inputs and resonance frequencies and the transfer of vibration (Transmissibility) from one component to another.
Technical Paper

Field Failure Simulation of a Non-reactive Suspension Tie Rod for Heavy Commercial Vehicle Using a Road Simulator

The suspension system in a vehicle isolates the frame and body from road shocks and vibrations which would otherwise be transferred to the passengers and goods. Heavier goods vehicles use tandem axles at the rear for load carrying. Both the axles should be inter-connected to eliminate overloading of any one axle when this goes over a bump or a ditch. One of the inter-connecting mechanism used is leaf spring with tie rod, bell crank & linkages, when the first rear axle moves over a bump, the linkages equalize the loading on the second rear axle. This paper details about the failure analysis methodology to simulate the tie rod field failure using a six poster road simulator and to identify the root cause of the failure and further corrective actions.

Relating Experimental Drive Distraction and Driving Performance Metrics to Crash Involvement - Definitions of Terms and Concepts

This Information Report provides functional definitions and discussions of key terms and concepts for relating the experimental evaluation of driver distraction to real-world crash involvement. Examples of driver distraction and driving performance metrics include those related to vehicle control, object and event detection and response (OEDR), physiological indicators, subjective assessments, or combinations thereof. Examples of real-world crash involvement metrics include the epidemiological effect size measures of risk ratio, rate ratio, and odds ratio. The terms and concepts defined in this document are not intended to contribute to methodologies for assessing the individual metrics within a domain; these are covered in other SAE documents (e.g., SAE J2944) and SAE technical reports. For any measure chosen in one domain or the other, the goal is to give general definitions of key terms and concepts that relate metrics in one domain to those in the other.
Technical Paper

Efficient Trim Modelling Simulation Method for Vehicle Design Phase

During the design phase of a vehicle, it is important to have a simulation tool, which allows to make multiple runs and check the sensitivity of the acoustic response to several trim configurations with a quick turnover time. The Statistical Energy Analysis (SEA) is widely used to investigate such problems for airborne excitation. For structure-borne excitation, classical methods based on a simplistic modeling of the trim using 1D oscillators and non-structural mass are not accurate enough to capture the actual behavior of the trim. On the other hand, a detailed Finite Element-Poroelastic Element Method (FE-PEM) modeling strategy of the trim may be time consuming. Besides the large number of degrees of freedom required to accurately model dissipative materials (e.g. poroelastic), a FE-based approach also needs a preprocessing phase where each layer of the trims must be carefully meshed.
Technical Paper

Parameters Analysis of on-Center Handling for Articulated Trucks

On-center handling is one of the most important test conditions which are used to evaluate the handling performance of both passenger cars and commercial vehicles. This paper aims at investigating and verifying the influence of parameters on on-center handling of articulated trucks. A full vehicle model, including the steering system, suspension system, cab, frame, trailer and so on, was established in first by measuring the parameters of each component. The comparison of simulation and test results shown that the simulation precision of the vehicle model was up to 80%. Based on the model, the influence analysis of parameters, such as stiffness of steering drag link, steering ratio, kingpin friction, were carried out and were verified through the handling test. The analysis results indicated that larger stiffness of steering drag link, smaller gear ratio could enhance the steer sensitivity and steer stiffness, small kingpin friction is beneficial to the steering return ability.
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Committed to being the primary source for aerospace and ground vehicle engineering resources, SAE International has added the full compilation of our Wiley eBook collections to the SAE MOBILUS® technical resource platform. Purchasable as an annual subscription and containing the titles from the Wiley Aerospace Collection, the Wiley Automotive Collection, the Wiley Computer Systems Collection, and the Wiley Cyber Security Collection.
Technical Paper

Estimating the CO2 Emissions Reduction Potential of Various Technologies in European Trucks Using VECTO Simulator

Heavy-duty vehicles (HDVs) account for some 5% of the EU’s total greenhouse gas emissions. They present a variety of possible configurations that are deployed depending on the intended use. This variety makes the quantification of their CO2 emissions and fuel consumption difficult. For this reason, the European Commission has adopted a simulation-based approach for the certification of CO2 emissions and fuel consumption of HDVs in Europe; the VECTO simulation software has been developed as the official tool for the purpose. The current study investigates the impact of various technologies on the CO2 emissions of European trucks through vehicle simulations performed in VECTO. The chosen vehicles represent average 2015 vehicles and comprised of two rigid trucks (Class 2 and 4) and a tractor-trailer (Class 5), which were simulated under their reference configurations and official driving cycles.
Technical Paper

A New Method to Accelerate Road Test Simulation on Multi-Axial Test Rig

Road test simulation on test rig is widely used in the automobile industry to shorten the development circles. However, there is still room for further improving the time cost of current road simulation test. This paper described a new method considering both the damage error and the runtime of the test on a multi-axial test rig. First, the fatigue editing technique is applied to cut the small load in road data to reduce the runtime initially. The edited road load data could be reproduced on a multi-axial test rig successfully. Second, the rainflow matrices of strains on different proving ground roads are established and transformed into damage matrices based on the S-N curve and Miner rules using a reduction method. A standard simulation test for vehicle reliability procedure is established according to the proving ground schedule as a target to be accelerated.
Technical Paper

Fuel Economy Variability Investigations: From Test Cells to Real World

Improving fuel economy has been a key focus across the automotive industry for several years if not decades. For heavy duty commercial vehicles, the benefits from minor gains in fuel economy can lead to significant savings for fleets as well as owners and operators. Additionally, the regulations require vehicles to meet certain GHG standards which closely translate to vehicle fuel economy. For current state of the art fuel economy technologies, incremental gains are so miniscule that measurements on the vehicle are inadequate to quantify the benefits. Engineers are challenged with high level of variability to make informed decisions. In such cases, highly controlled tests on Engine and Powertrain dynamometers are used, however, there is an associated variability even with these tests due to factors such as part to part differences, deterioration, fuel blends and quality, dyno control capabilities and so on.
Technical Paper

Implementation of an Extended Model for Multi-Axle Articulated Vehicle with Nonlinear Tire Model

A new extended planar model for multi-axle articulated vehicle with nonlinear tire model is presented. This nonlinear multi-axle articulated vehicle model is specifically intended for improving the model performance in operating regimes where tire lateral force is near the point of saturation, and it has the potential to extend the specific axles model to any representative configuration of articulated vehicle model. At the same time, the extended nonlinear vehicle model can reduce the model's sensitivity to the tire cornering coefficients. Firstly, a nonlinear tire model is used in conjunction with the 6-axle planar articulated vehicle model to extend the ranges of the original linear model into the nonlinear regimes of operation. Secondly, the performance analysis of proposed nonlinear vehicle model is verified through the double lane change maneuver on different road adhesion coefficients using TruckSim software.