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Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks

SAE International Journal of Commercial Vehicles

AxleTech, United States-Molly O’Malley
Primus Solutions Inc., United States-Brandon Card
  • Journal Article
  • 02-12-03-0016
Published 2019-08-28 by SAE International in United States
Vehicle rolling resistance and weight are two of the factors that affect fuel economy. The vehicle tire rolling resistance has a more significant influence than aerodynamics drags on fuel economy at lower vehicle speeds, particularly true for medium- and heavy-duty trucks. Less vehicle weight reduces inertia loads, uphill grade resistance, and rolling resistance. The influence of weight on the fuel economy can be considerable particularly in light- to medium-duty truck classes because the weight makes up a larger portion of gross vehicle weight. This article presents an empirical investigation and a numerical analysis of the influences of rolling resistance and weight on the fuel economy of medium-duty trucks. The experimental tests include various tires and payloads applied on a total of 21vehicle configurations over three road profiles. These tests assessed the sensitivity of the vehicle’s fuel economy toward rolling resistance and weight. Several experimental results showed inconsistent and counterintuitive trends of the effects of rolling resistance coefficients and weights on fuel economy. The consequences of rolling resistance and vehicle payload are compound and influenced by…
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Determination of a Tyre’s Rolling Resistance Using Parallel Rheological Framework

University of Birmingham-Hamad Sarhan Aldhufairi, Oluremi Olatunbosun, Khamis Essa
Published 2019-06-20 by SAE International in United States
Nowadays, rolling resistance sits at the core of tyre development goals because of its considerable effect on the car’s fuel economy. In contrast to the experimental method, the finite element (FE) method offers an inexpensive and efficient estimation technique. However, the FE technique is yet to be a fully developed product particularly for rolling-resistance estimation. An assessment is conducted to study the role of material viscoelasticity representation in FE, in linear and non-linear forms, through the use of Prony series and parallel rheological framework (PRF) models, respectively, on the tyre’s rolling-resistance calculation and its accuracy. A unique approach was introduced to estimate the rolling resistance according to the tyre’s hysteresis energy coefficient. The non-linear PRF choice resulted in rolling-resistance calculations that reasonably match that of the experimental work and the literature for various vertical load and inflation cases, whereas the Prony series option was found irresponsive to the tyre’s deformation in which it gave unreliable and infinitesimal outputs.
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Landing Gear Shock Absorption Testing of Civil Aircraft

A-5B Gears, Struts and Couplings Committee
  • Aerospace Standard
  • ARP5644
  • Current
Published 2019-04-17 by SAE International in United States
The intent of this document is to provide recommended practices for conducting shock absorption testing of civil aircraft landing gear equipped with oleo-pneumatic shock absorbers. The primary focus is for Part 25 aircraft, but differences for Part 23, 27, and 29 aircraft are provided where appropriate.
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Multi-Chamber Tire Concept for Low Rolling-Resistance

SAE International Journal of Passenger Cars - Mechanical Systems

University of Birmingham, UK-Hamad Sarhan Aldhufairi, Khamis Essa, Oluremi Olatunbosun
  • Journal Article
  • 06-12-02-0009
Published 2019-04-08 by SAE International in United States
Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating the tread from sidewalls would maintain tire’s profile effectively. Different air concentration across the tire’s chambers gave the tire extended versatility. Rolling non-uniformity depends upon inner-chambers’ stability, sidewalls’ flexibility and tire/chamber(s) integration.
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A Combination of Intelligent Tire and Vehicle Dynamic Based Algorithm to Estimate the Tire-Road Friction

SAE International Journal of Passenger Cars - Mechanical Systems

NIO, USA-Omid Ghasemalizadeh
Texas State University, USA-Seyedmeysam Khaleghian
  • Journal Article
  • 06-12-02-0007
Published 2019-04-08 by SAE International in United States
One of the most important factors affecting the performance of vehicle active chassis control systems is the tire-road friction coefficient. Accurate estimation of the friction coefficient can lead to better performance of these controllers. In this study, a new three-step friction estimation algorithm, based on intelligent tire concept, is proposed, which is a combination of experiment-based and vehicle dynamic based approaches. In the first step of the proposed algorithm, the normal load is estimated using a trained Artificial Neural Network (ANN). The network was trained using the experimental data collected using a portable tire testing trailer. In the second step of the algorithm, the tire forces and the wheel longitudinal velocity are estimated through a two-step Kalman filter. Then, in the last step, using the estimated tire normal load and longitudinal and lateral forces, the friction coefficient can be estimated. To evaluate the performance of the algorithm, experiments were performed using the trailer test setup and friction was calculated using the measured forces. Good agreement was observed between the estimated and actual friction coefficients.
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Extended Kalman Filter Based Road Friction Coefficient Estimation and Experimental Verification

APTIV PLC-Bin Li, Guobiao Song
Ford Motor Co., Ltd.-Arlene Fang
Published 2019-04-02 by SAE International in United States
Accurate road friction coefficient is crucial for the proper functioning of active chassis control systems. However, road friction coefficient is difficult to be measured directly. Using the available onboard sensors, a model-based Extended Kalman filter (EKF) algorithm is proposed in this paper to estimate road friction coefficient. In the development of estimation algorithm, vehicle motion states such as sideslip angle, yaw rate and vehicle speed are first estimated. Then, road friction coefficient estimator is designed using nonlinear vehicle model together with the pre-estimated vehicle motion states. The proposed estimation algorithm is validated by both simulations and tests on a scaled model vehicle.
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Estimation of Side Slip Angle Interacting Multiple Bicycle Models Approach for Vehicle Stability Control

Andong National University-Bongchoon Jang
Chassis R&D-Youngjin Hyun
Published 2019-04-02 by SAE International in United States
This paper presents an Interacting Multiple Model (IMM) based side slip angle estimation method to estimate side slip angle under various road conditions for vehicle stability control. Knowledge of the side slip angle is essential enhancing vehicle handling and stability. For the estimation of the side slip angles in previous researches, prior knowledge of tire parameters and road conditions have been employed, and sometimes additional sensors have been needed. These prior knowledge and additional sensors, however, necessitates many efforts and make an application of the estimation algorithm difficult. In this paper, side slip angle has been estimated using on-board vehicle sensors such as yaw rate and lateral acceleration sensors. The proposed estimation algorithm integrates the estimates from multiple Kalman filters based on the multiple models with different parameter set. The IMM approach enables a side slip angle estimation from originally equipped vehicle sensors without prior knowledge of tire and road. The proposed estimation algorithm is evaluated via vehicle tests in electronic control unit level. The results have shown that the proposed estimator can successfully estimate…
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Rear-Wheel Steering Control for Enhanced Maneuverability of Vehicles

Seoul National University-Kwanwoo Park, Eunhyek Joa, Kyongsu Yi
Published 2019-04-02 by SAE International in United States
This paper proposes a rear-wheel steering control method that can modify and improve the vehicle lateral response without tire model and parameter. The proposed control algorithm is a combination of steady-state and transient control. The steady state control input is designed to modify steady-state yaw rate response of the vehicle, i.e. understeer gradient of the vehicle. The transient control input is a feedback control to improve the transient response when the vehicle lateral behavior builds up. The control algorithm has been investigated via computer simulations. Compared to classical control methods, the proposed algorithm shows good vehicle lateral response such as small overshoot and fast response. Specifically, the proposed algorithm can alleviate stair-shaped response of the lateral acceleration. In addition, through tests with low friction road and high lateral acceleration, the proposed algorithm’s performance is verified to be robust for a variety of road friction and nonlinear tire characteristics, since tire information is excluded.
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Uncertainty in Radius Determined by Multi-Point Curve Fits for Use in the Critical Curve Speed Formula

MEA Forensic Engineers & Scientists-Bradley Heinrichs, Troy Mithrush
Published 2019-04-02 by SAE International in United States
The critical curve speed formula used for estimating vehicle speed from yaw marks depends on the tire-to-road friction and the mark’s radius of curvature. This paper quantifies uncertainty in the radius when it is determined by fitting a circular arc to three or more points. A Monte Carlo analysis was used to generate points on a circular arc given three parameters: number of points n, arc angle θ, and point measurement error σ. For each iteration, circular fits were performed using three techniques. The results show that uncertainty in radius is reduced for increasing arc length, decreasing point measurement error, and increasing number of points used in the curve fit. Radius uncertainty is linear if the ratio of the standard deviation in point measurement error (σ) to the curve’s middle ordinate (m) is less than 0.1. The ratio σ/m should be less than 0.018 for a radius found using a 3-point circular fit to be within 5% of the actual value 95% of the time. Increasing the number of points used for the fit reduces…
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ABS Optimization for a Two-Wheeler Based on Tire-Road Friction Characteristics

Bosch Limited-Ashish Ranjan, Shreyansh Srivastava, Prashanth Anantha
Published 2019-01-09 by SAE International in United States
Anti-lock Braking System (ABS) is a well-known active safety technology widely used in cars. Recently, it has become a mandatory safety feature for two-wheelers. In principle, ABS ensures an optimum braking performance by not allowing the tire to slip beyond a certain level. This guarantees steering stability and peak braking performance of the tire during panic braking situations. As the ABS controller depends on the tire characteristics information for its algorithm, a change in tire or pavement can vary the optimum operating range of ABS. In addition to this, motorcycle tires differ from a car tire in terms of its construction, dimension and compound. Therefore, the motorcycle tire’s performance envelope cannot be directly compared to a car tire. This work presents a methodology which aims to acquire the tire-road friction characteristics of three different tires for a study motorcycle on different friction surfaces through experimentation and estimation techniques. The optimum pressure release slip thresholds for the three tires on different surfaces are then determined from the obtained tire characteristics. Further, the ABS controller is calibrated…
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