Tread Groove Void and Developed Tread Width (Aspect Ratio): Their Joint Influence on Wet Traction

Abstract Other than treadwear testing, tires are normally evaluated for important performance features in the virgin or new state. One performance feature that changes, as the tire wears in service, is wet traction. For any given tread compound the wet traction performance is jointly influenced by the groove void level (it changes with wear) and a factor that is a function of the aspect ratio, the “developed tread width,” i.e., the actual width that contacts the road surface. Based on a comprehensive testing program, a wet traction performance parameter called the “specific discharge capacity” has been developed. This accounts for the interactive or joint influence of both of these factors and how this influence changes across a range of operating conditions (speed, pavement texture). The specific discharge capacity is especially important at high levels of “criticality”, i.e., deep water, slippery pavement, high speed.

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Stall Inception in a High-Speed Low Aspect Ratio Fan Including the Effects of Casing Treatments

Volume 1: Turbomachinery ◽

10.1115/94-gt-322 ◽

1994 ◽

Cited By ~ 2

Author(s):

S. E. Gorrell ◽

P. M. Russler

Keyword(s):

Aspect Ratio ◽

High Speed ◽

Static Pressure ◽

Pressure Ratio ◽

Rotating Stall ◽

Operating Conditions ◽

Stall Inception ◽

Casing Treatment ◽

Low Aspect Ratio ◽

Casing Treatments

The stall inception process in high-speed compressor components is important to understand in order to increase stage loading while maintaining stall margin. This paper presents the results of an in depth experimental investigation on the stall inception of a two stage, high-speed, low aspect ratio fan that is representative of current operational commercial and military fan technology. High-response static pressure measurements are presented which detail the stall inception process of the fan under various operating conditions. These conditions include: varied corrected speeds, a smooth case, a circumferential groove casing treatment, and a recirculating cavity casing treatment. Stage pressure characteristics and radial pressure ratio profiles are presented for the different operating conditions. The stage performance data, together with the static pressure data, are analyzed to provide a clear and thorough understanding of the stall inception process and how the process may vary under different conditions. Experimental results show that a stage may stall on the positive, neutral, or negative sloped part of the pressure characteristic. The three casing treatments had a significant effect on the rotor tip flow and these variations changed the stall inception path of the fan. Stall inception was characterized by the formation of a stall inception cell which grew to fully developed rotating stall. Properties affected by the changing tip flow include the stall inception duration, stall inception cell frequency, existence of modal waves, duration of modal waves, and modal wave frequency. In some instances modal waves appear to play a role in stall inception, in others they do not.

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Levels of vibration transmitted to the operator of the tractor equipped with front axle suspension

Journal of Agricultural Engineering ◽

10.4081/jae.2013.393 ◽

2013 ◽

Vol 44 (2s) ◽

Author(s):

Daniele Pochi ◽

Roberto Fanigliulo ◽

Laura Fornaciari ◽

Gennaro Vassalini ◽

Marco Fedrizzi ◽

...

Keyword(s):

High Speed ◽

Travel Speed ◽

Front Axle ◽

Operating Conditions ◽

Road Surface ◽

Air Conditioner ◽

Test Results ◽

The Road ◽

Seat Suspension ◽

Agricultural Tractors

In recent years the comfort and the preservation of the health of the operators became central issues in the evolution of agricultural machinery and led to the introduction of devices aimed at improving working conditions. Thereby, for instance, the presence of air conditioner, soundproof cab and driver seat suspension became normal on agricultural tractors. The vibrations are one of the most complex issues to deal with, being determined by the characteristics and interaction of elements such as tyres, axles, mainframe, cab and seat suspension. In this respect, manufacturers are trying to improve their products, even integrating these elements with new devices such as the suspension on the front axle of the tractor, aimed at reducing the level of vibrations during the transfers at high speed. One of these underwent tests at CRA-ING. Since its purpose is to reduce the level of vibration transmitted to the driver, their measurements in different points of the tractor and in different operating conditions, were compared in order to evaluate the effectiveness of the device, expressed as time of exposure. The suspension system of the front axle is designed to absorb the oscillations (especially pitching) determined by irregularities in the road surface, allowing an increased control of the vehicle at high speed, as demonstrated by the test results and confirmed by the driving impressions outlined by the operator. The action of the device under these conditions results in an increase of the exposure time, important fact because of the relevance of the road transfer operations of tractors with mounted implements or trailers to tow and of the tendency to increase the speed limit for the road tractors (in Germany were brought to 50 km h–1 for several years). The action just described is less evident with increasing irregularity of the road surface and with the decrease of the travel speed. Nevertheless, in such conditions, the device appears to positively work along the other directions, in particular in the Z-axis, improving the action of the suspension of the driver seat.

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Objective Tire Footprint Segmentation Assessment from High-Speed Videos

Tire Science and Technology ◽

10.2346/tire.19.180203 ◽

2019 ◽

Vol 48 (4) ◽

pp. 315-328

Author(s):

Rodrigo Nava ◽

Duc Fehr ◽

Frank Petry ◽

Thomas Tamisier

Keyword(s):

High Speed ◽

Accurate Determination ◽

Ground Truth ◽

Operating Conditions ◽

Contact Patch ◽

The Road ◽

Quantitative Image ◽

Processing Techniques

ABSTRACT The tire establishes the contact between the vehicle and the road. It transmits all forces and moments to the road via its contact patch or footprint and vice versa. The visual inspection of this contact patch using modern optical equipment and image processing techniques is essential for evaluating tire performance. Quantitative image-based analysis can be useful for accurate determination of tire footprint under various operating conditions. Very frequently, methods used in tire footprint segmentation cannot be assessed quantitatively due to the lack of a reference contact area to which the different algorithms could be compared. In this work, we present a novel methodology to characterize the dynamic tire footprint and evaluate the quality of its segmentation from various video sequences in the absence of a ground truth.

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An experimental study with renewable fuels using ECN Spray A and D nozzles

International Journal of Engine Research ◽

10.1177/14680874211031200 ◽

2021 ◽

pp. 146808742110312

Author(s):

José V Pastor ◽

José M García-Oliver ◽

Carlos Micó ◽

Alba A García-Carrero

Keyword(s):

High Speed ◽

Soot Formation ◽

Road Transport ◽

Operating Conditions ◽

Nozzle Geometry ◽

Transport Sector ◽

The Road ◽

Auto Ignition ◽

Lift Off ◽

Oxygenated Fuels

The decarbonization process of the automotive industry and the road transport sector has raised the interest on the development of cleaner fuels. A proper characterization of their properties and behavior under different operating conditions is mandatory to achieve an effective implementation in commercial engines. With this objective, the current work presents a comparison of two injectors from the Engine Combustion Network (ECN), namely Spray A and Spray D injectors, in terms of spray characteristics and combustion behavior for different fuels: diesel, dodecane, Hydrotreated Vegetable Oil (HVO), and two types of oxymethylene ethers (OME1 and OME x). The aim is to analyze how differences in nozzle geometry affect the behavior of different types of fuels. The experiments were carried out in a High Temperature and High Pressure test rig and operating conditions were chosen following ECN guidelines. Visualization techniques such as high speed schlieren imaging, OH* chemiluminescence and diffused back illumination were implemented to analyze the differences in liquid length, vapor penetration, auto ignition, flame lift-off length, and soot formation for both nozzles. In general, results showed the same trend for all the fuels tested: longer liquid length and faster vapor penetration for Spray D, as well as higher ignition delay and longer lift-off length. However, it was found that these parameters were less sensitive to the nozzle diameter for the oxygenated fuels tested. Furthermore, a different trend was observed for OME1, in terms of ignition behavior, in comparison to the other fuels. In terms of soot production, the Spray D nozzle increases its formation with the non-oxygenated fuels. In contrast, no soot was observed with the oxygenated ones under any operating conditions.

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Investigations of Road Wear Caused by Studded Tires

Tire Science and Technology ◽

10.2346/tire.14.420101 ◽

2014 ◽

Vol 42 (1) ◽

pp. 2-15

Author(s):

Johannes Gültlinger ◽

Frank Gauterin ◽

Christian Brandau ◽

Jan Schlittenhard ◽

Burkhard Wies

Keyword(s):

Traffic Safety ◽

Test Bench ◽

Operating Conditions ◽

Test Method ◽

Analytical Models ◽

The Road ◽

Driving Speed ◽

Major Factors ◽

Tire Friction ◽

Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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Experimental Evaluation of Turbo-Matching Appropriateness of B60J67, B60J68, A58N70 and A58N72 Turbo-Chargers for a Commercial Vehicle Engine

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i11.49 ◽

2018 ◽

Vol 6 (11) ◽

pp. 71

Author(s):

Badal Dev Roy ◽

R. Saravanan

Keyword(s):

Internal Combustion Engines ◽

Perfect Match ◽

Engine Performance ◽

Operating Conditions ◽

Data Logger ◽

Negative Effects ◽

Road Test ◽

The Road ◽

A Charge ◽

All Speeds

The Turbocharger is a charge booster for internal combustion engines to ensure best engine performance at all speeds and road conditions especially at the higher load. Random selection of turbocharger may lead to negative effects like surge and choke in the breathing of the engine. Appropriate selection or match of the turbocharger (Turbomatching) is a tedious task and expensive. But perfect match gives many distinguished advantages and it is a one time task per the engine kind. This study focuses to match the turbocharger to desired engine by simulation and on road test. The objective of work is to find the appropriateness of matching of turbochargers with trim 67 (B60J67), trim 68 (B60J68), trim 70 (A58N70) and trim 72 (A58N72) for the TATA 497 TCIC -BS III engine. In the road-test (data-logger method) the road routes like highway and slope up were considered for evaluation. The operating conditions with respect various speeds, routes and simulated outputs were compared with the help of compressor map.

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RCVC: RSU-Aided Cluster-Based Vehicular Clouds Architecture for Urban Areas

Electronics ◽

10.3390/electronics10020193 ◽

2021 ◽

Vol 10 (2) ◽

pp. 193

Author(s):

Mohamed Ben bezziane ◽

Ahmed Korichi ◽

Chaker Abdelaziz Kerrache ◽

Mohamed el Amine Fekair

Keyword(s):

Urban Areas ◽

High Speed ◽

Service Discovery ◽

Cluster Head ◽

Experimental Comparison ◽

The Road ◽

Road Side Unit ◽

End To End Delay ◽

End To End ◽

On The Road

As a promising topic of research, Vehicular Cloud (VC) incorporates cloud computing and ad-hoc vehicular network (VANET). In VC, supplier vehicles provide their services to consumer vehicles in real-time. These services have a significant impact on the applications of internet access, storage and data. Due to the high-speed mobility of vehicles, users in consumer vehicles need a mechanism to discover services in their vicinity. Besides this, quality of service varies from one supplier vehicle to another; thus, consumer vehicles attempt to pick out the most appropriate services. In this paper, we propose a novel protocol named RSU-aided Cluster-based Vehicular Clouds protocol (RCVC), which constructs the VC using the Road Side Unit (RSU) directory and Cluster Head (CH) directory to make the resources of supplier vehicles more visible. While clusters of vehicles that move on the same road form a mobile cloud, the remaining vehicles form a different cloud on the road side unit. Furthermore, the consumption operation is achieved via the service selection method, which is managed by the CHs and RSUs based on a mathematical model to select the best services. Simulation results prove the effectiveness of our protocol in terms of service discovery and end-to-end delay, where we achieved service discovery and end-to-end delay of 3 × 10−3 s and 13 × 10−2 s, respectively. Moreover, we carried out an experimental comparison, revealing that the proposed method outperformed several states of the art protocols.

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Hysteresis loss of ultra-large off-the-road tire rubber compounds based on operating conditions at mine sites

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211015525 ◽

2021 ◽

pp. 095440702110155

Author(s):

Shaosen Ma ◽

Guangping Huang ◽

Khaled Obaia ◽

Soon Won Moon ◽

Wei Victor Liu

Keyword(s):

Large Strain ◽

Tensile Tests ◽

Operating Conditions ◽

Hysteresis Loss ◽

Strain Rates ◽

Test Results ◽

Tire Rubber ◽

The Road ◽

Rubber Compounds ◽

Mine Sites

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.

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