Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Effect of variable payload on Vehicle dynamics of Passenger buses in Indian usage conditions

2019-11-21
2019-28-2411
A high impetus from Government on road infrastructure development, is giving a fillip to passenger CV space. This has resulted in making the passenger CV segment lucrative enough, thereby pulling in many operators in the business. The quality of road has immensely improved over a decade, as a result of which the average speed and hence the quantum of distance covered by passenger buses has increased significantly. People are preferring to travel in buses over trains, owing to at par ticket cost, high availability, reduced travel time and also improved level of comfort. Aligned to the market need and the trend, OEM's are offering buses with capable powertrains to cater the need of speed, reduced trip time as well as a lot of attention is also being paid to tune in the comfort level for long hauls. A big chunk of passenger travel is catered by the bus operators especially during major festivals in India.
Technical Paper

The Dynamic Stability Index Calculator for Agricultural Tractors Equipped with Front End Loader

2019-11-21
2019-28-2420
The study aims to evaluate the lateral stability of tractor-front end loader system in consideration with difficult work conditions based on various loader bucket lifting heights from ground while driving a system on transversal slopes. In the proposed method the centre of gravity of tractor-front end loader system was calculated and analysed to evaluate the transversal overturning of the system. This overturning of the system was analysed by applying mathematical equations presented in past studies and compared with the newly developed prediction model for 3 test tractors of 25 HP. The excel spreadsheet comprised of mathematical equations used to calculate the Tractor Stability Index (TSI) on transverse slope with respect to loader bucket height and payload in dynamic condition. A criterion has been defined to categorize the Tractor Stability Index (TSI) poor to excellent on a scale of 0 to 4 where <0 being the very poor, 0-2 Poor, 2-4 Good and >4 being the excellent.
Technical Paper

Multi body dynamic simulation of tyre traction trailer

2019-11-21
2019-28-2430
Tyre Traction Trailer is a device designed to find the Peak Brake co-efficient of C2 and C3 tyre as per ECE R117. The trailer is towed by the truck and is braked suddenly to evaluate braking co-efficient of specimen tyre. It is a single wheel trailer equipped with load cell to capture tire loads (Normal and longitudinal)while braking. Traction Trailer is modelled in MSC Adams and rigid body simulation is carried out for static stability of the system. Dynamic simulations were performed to understand locking of wheels during braking. Body frame was further modelled as flex body to perform structural analysis of the frame. The paper contains stress and deformation plots of trailer Structure under various loading conditions, change in Centre of gravity, weight transfer and forces on springs during braking and cornering, plots of tractive and normal load on tyre during braking.
Training / Education

Tire and Wheel Safety Issues

2019-11-07
One of the most important safety critical components on cars, trucks, and aircraft is the pneumatic tire. Vehicle tires primarily control stopping distances on wet and dry roads or runways and strongly influence over-steer/under-steer behavior in handling maneuvers of cars and trucks. The inflated tire-wheel assembly also acts as a pressure vessel that releases a large amount of energy when catastrophically deflated. The tire can also serve as a fulcrum, both directly and indirectly, in contributing to vehicle rollover. This seminar covers these facets of tire safety phenomena.
Training / Education

Applied Vehicle Dynamics

2019-10-21
While a variety of new engineering methods are becoming available to assist in creating optimal vehicle designs, subjective evaluation of vehicle dynamics is still required to deliver desired braking, handling, and acceleration attributes. In order to better prepare today’s engineer for this task, this course offers modules devoted to twelve key fundamental principles associated with longitudinal and lateral vehicle dynamics. Each focused classroom session is paired with an on-track exercise to immediately reinforce these concepts with a dedicated behind-the-wheel driving session, effectively illustrating these principles in the real world.
Journal Article

Speed Planning and Prompting System for Commercial Vehicle Based on Real-Time Calculation of Resistance

2019-06-25
Abstract When commercial vehicles drive in a mountainous area, the complex road condition and long slopes cause frequent acceleration and braking, which will use 25% more fuel. And the brake temperature rises rapidly due to continuous braking on the long-distance downslopes, which will make the brake drum fail with the brake temperature exceeding 308°C [1]. Meanwhile, the kinetic energy is wasted during the driving progress on the slopes when the vehicle rolls up and down. Our laboratory built a model that could calculate the distance from the top of the slope, where the driver could release the accelerator pedal. Thus, on the slope, the vehicle uses less fuel when it rolls up and less brakes when down. What we do in this article is use this model in a real vehicle and measure how well it works.
Technical Paper

Driveline NVH Integration of An NA Truck Program

2019-06-05
2019-01-1559
In the current automotive industry, it is common that the driveline subsystem and components are normally from different automotive suppliers for OEMs. In order to ensure proper system integration and successful development of driveline system NVH performances, collaboration efforts between OEMs and suppliers are very demanding and important. In this paper, a process is presented to achieve successfulness in developing and optimizing vehicle integration through effective teamwork between a driveline supplier and a major OEM. The development process includes multiple critical steps. They include target development and roll down, targets being specific and measurable, comprehension of interactions of driveline and vehicle dynamics, accurate definition of sensitivity, proper deployment of modal mapping strategy, which requires open data sharing; and system dynamics and optimization.
Standard

Cutting Edge - Double Bevel Cross Sections

2019-04-22
WIP
J738
This standard is for cutting edge sections typically used in earth-moving machinery defined in SAE J1116 and ISO 6165: a. Scrapers as defined in ISO 7133. b. Dozers as described in ISO 6747. c. Loaders as described in ISO 7131. d. Graders as described in ISO 7134. Hole spacing is defined ISO 7129. Hole conformation is defined in SAE J740.
Standard

Setting Preload in Heavy-Duty Wheel Bearings

2019-04-22
WIP
J2535
This SAE Recommended Practice applies to the four primary, large volume applications in the class 7-8 heavy-duty market place, as specified in SAE J1842: a. “N” trailer axle b. “R” powered rear axle c. “FF / FG” nonpowered front axle d. “P” trailer axle This document applies to on-highway applications. It is not applicable to those applications that exceed the GAWR ratings or the load line restrictions listed in columns “A,” “B,” and “C” of Table 1. Load lines are measured from the inboard bearing cup backface as shown in 3.4. This document establishes preload force values only. The methodology to obtain these force values must be determined by the fastener supplier and/or axle assembler. This document reviews the bearing system. It is NOT intended to prescribe (new or existing) axle and/or hub manufacturers’ ratings and/or specifications.
Technical Paper

A Non-Contact Overload Identification Method Based on Vehicle Dynamics

2019-04-02
2019-01-0490
The vehicle overload seriously jeopardizes traffic safety and affects traffic efficiency. At present, the static weighing station and weigh-in-motion station are both relatively fixed, so the detection efficiency is not high and the traffic efficiency is affected; the on-board dynamic weighing equipment is difficult to be popularized because of the problem of being deliberately damaged or not accepted by the purchaser. This paper proposes an efficient, accurate, non-contact vehicle overload identification method which can keep the road unimpeded. The method can detect the vehicle overload by the relative distance (as the characteristic distance) between the dynamic vehicle's marking line and the road surface. First, the dynamics model of the vehicle suspension is set up. Then, the dynamic characteristic distance of the traffic vehicle is detected from the image acquired by the calibrated camera based on computer vision and image recognition technology.
Technical Paper

Active Steering and Anti-Roll Shared Control for Enhancing Roll Stability in Path Following of Autonomous Heavy Vehicle

2019-04-02
2019-01-0454
Rollover accident of heavy vehicle during cornering is a serious road safety problem worldwide. In the past decade, based on the active intervention into the heavy vehicle roll dynamics method, researches have proposed effective anti-roll control schemes to guarantee roll stability during cornering. Among those studies, however, roll stability control strategies are generally derived independent of front steering control inputs, the interactive control characteristic between steering and anti-roll system have not been thoroughly investigated. In this paper, a novel roll stability control structure that considers the interaction between steering and anti-roll system, is presented and discussed.
Technical Paper

Aerodynamic Characteristics Simulation of Heavy Commercial Vehicles Passing through Expressway Tunnel in Cross Wind

2019-04-02
2019-01-0666
Considering the aerodynamic characteristics of the vehicle traveling under the crosswind and the complexity of the flow field change, this paper uses overset mesh of STAR CCM+ software to carry out CFD simulation analysis on the aerodynamic characteristics of heavy commercial vehicles passing through the highway tunnel of which entrance and exit exist crosswind. Corresponding aerodynamic coefficients and flow field changes around the body at different crosswind speeds and different tunnel forms are monitored. The results show that the yaw moment is sensitive to the speed of crosswind. When a heavy commercial vehicle passes through a tunnel where crosswind increases from 10m/s to 13m/s,the yaw moment change rate increases from 34.8 kN•m/s to 45.9 kN•m/s. It also can be seen in these results is that when passing through two tunnels with a distance, the heavy commercial vehicle’s side force, roll moment and yaw moment change because of the surrounding periodic variation of flow field.
Technical Paper

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

2019-04-02
2019-01-0784
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

Has Electronic Stability Control Reduced Rollover Crashes?

2019-04-02
2019-01-1022
Vehicle rollovers are one of the more severe crash modes in the US - accounting for 32% of all passenger vehicle occupant fatalities annually. One design enhancement to help prevent rollovers is Electronic Stability Control (ESC) which can reduce loss of control and thus has great promise to enhance vehicle safety. The objectives of this research were (1) to estimate the effectiveness of ESC in reducing the number of rollover crashes and (2) to identify cases in which ESC did not prevent the rollover to potentially advance additional ESC development. All passenger vehicles and light trucks and vans that experienced a rollover from 2006 to 2015 in the National Automotive Sampling System Crashworthiness Database System (NASS/CDS) were analyzed. Each rollover was assigned a crash scenario based on the crash type, pre-crash maneuver, and pre-crash events.
Technical Paper

Low Speed Override of Passenger Vehicles with Heavy Trucks

2019-04-02
2019-01-0430
In low speed collisions (under 15 mph) that involve a heavy truck impacting the rear of a passenger vehicle, it is likely that the front bumper of the heavy truck will override the rear bumper beam of the passenger vehicle, creating an override/underride impact configuration. There is limited data available for study when attempting to quantify vehicle damage and crash dynamics in low-speed override/underride impacts. Low speed impact tests were conducted to provide new data for passenger vehicle dynamics and damage assessment for low speed override/underride rear impacts to passenger vehicles. Three tests were conducted, with a tractor-trailer impacting three different passenger vehicles at 5 mph and 10 mph. This paper presents data from these three tests in order to expand the available data set for low speed override/underride collisions.
Technical Paper

Accuracy and Sensitivity of Yaw Speed Analysis to Available Data

2019-04-02
2019-01-0417
Accident reconstructionists rarely have complete data with which to determine vehicle speed, and so the true value must be bracketed within a range. Previous work has shown the effect of friction uncertainty in determining speed from tire marks left by a vehicle in yaw. The goal of the current study was to assess improvements in the accuracy of vehicle speed estimated from yaw marks using progressively more scene and vehicle information. Data for this analysis came from staged S-turn maneuvers that in some cases led to rollover of sport utility vehicles. Initial speeds were first calculated using the critical curve speed (CCS) formula on the yaw marks from the first portion of the S-maneuver. Then computer simulations were performed with progressively more input data: i) the complete tire marks from the whole S-maneuver, ii) measured vehicle mass, iii) measured suspension stiffness and damping, and iv) measured steering history.
Technical Paper

Flow around a Heavy Vehicle in a Side Wind

2019-03-21
2019-01-5019
Driving stability can be an issue for heavy vehicles. In a side wind, a side force and rolling moment will develop, and they both affect driving stability, from which the vehicle may overturn. It is important to understand the flow structure in order to prevent a truck from rolling over. The main purpose of this study is to investigate the flow around a heavy vehicle that causes it to overturn. A 1/8 scaled, simplified tractor/trailer configuration called the Ground Transportation System (GTS) with Reynolds number (based on the GTS width) equal to 1.6 × 106 was used for this study. A side wind was modeled by turning the GTS model with respect to its moment reference point. A triangular mesh was used for the truck and the computational domain surfaces, while hybrid meshes filled the computational domain volume. The Ansys® CFX code based on the k-ω shear stress transport (SST) turbulence model was used to solve the governing equations numerically for an incompressible fluid.
Journal Article

Fatigue Evaluation of Multi-Degree of Freedom, Frequency Domain, Stochastic, Truck Road Load Models

2019-02-11
Abstract A number of semi-deterministic and stochastic formulations of multi-degree of freedom, frequency domain load models for heavy truck chassis are proposed and evaluated. The semi-deterministic models aim at reproducing the damage of a specific vehicle, while the stochastic ones aim to describe a collection of vehicle loads. The stochastic models are divided into two groups: Monte Carlo based and models based on single spectrum matrices. In both cases, the objective is to provide a load model that may be used to produce a design with a certain probability of survival. The goodness of the models is evaluated through a comparison of their damage outcomes with the corresponding damages of a set of time domain loads. This original time domain load set consists of chassis accelerations collected from seven physical trucks.
Technical Paper

Response Decoupling Method in Mount Design with Emphasis on Transient Load Conditions

2019-01-18
2018-01-5046
This research examined the focused design, elastic design, energy decoupling, and torque roll axis (TRA) decoupling methods for mount optimization design. Requiring some assumptions, these methods are invalid for some load conditions and constraints. The linearity assumption is advantageous and simplifies both design and optimization analysis, facilitating engineering applications. However, the linearity is rarely seen in real-world applications, and there is no practical method to directly measure the reaction forces in the three locally orthogonal directions, preventing validation of existing methods by experimental results. For nonlinear system identification, there are additional challenges such as unobservable internal variables and the uncertainty of measured data.
Journal Article

Model-Based Approaches in Developing an Advanced Aftertreatment System: An Overview

2019-01-15
2019-01-0026
Cummins has recently launched next-generation aftertreatment technology, the Single ModuleTM aftertreatment system, for medium-duty and heavy-duty engines used in on-highway and off-highway applications. Besides meeting EPA 2010+ and Euro VI regulations, the Single ModuleTM aftertreatment system offers 60% volume and 40% weight reductions compared to current aftertreatment systems. In this work, we present model-based approaches that were systematically adopted in the design and development of the Cummins Single ModuleTM aftertreatment system. Particularly, a variety of analytical and experimental component-level and system-level validation tools have been used to optimize DOC, DPF, SCR/ASC, as well as the DEF decomposition device.
X