Author:
Publisher:
ISBN:
Category : Trucks
Languages : en
Pages : 4
Book Description
Performance-based brake testers-round robin study
Author:
Publisher:
ISBN:
Category : Trucks
Languages : en
Pages : 4
Book Description
Publisher:
ISBN:
Category : Trucks
Languages : en
Pages : 4
Book Description
Performance-based Brake Testers
Author: United States. Federal Highway Administration. Office of Motor Carriers
Publisher:
ISBN:
Category : Motor vehicles
Languages : en
Pages :
Book Description
This report documents the results of a series of tests in which several different types of performance-based brake testers (PBBTs) were compared side-by-side (i.e. a round robin test) in their ability to accurately measure brake forces (BFs) and wheel loads (WLs) of commercial vehicles (CVs), and to then predict the vehicle deceleration capability for a 32.2 km/hr on-road stopping test. The PBBTs consisted of five roller dynamometers (RD), two flat plate (FP) testers, and one breakaway torque tester (BTT). A PBBT that can also meet a set of functional specifications could be used for law enforcement by safety inspectors once performance-based criteria are codified. In the test program, specific ratios of BF to WL were imposed on both a 5-axle combination tractor semi-trailer and a two-axle straight truck, in both the fully laden and unladen conditions. In each loading condition, the overall vehicle braking capability was set to achieve a proposed minimum requirement of 0.4g, where g is the acceleration due to gravity. In addition, the brakes on specific individual wheels were set to provide a BF/WL of 0.25 and 0.35, for a steer and a non-steer wheel, respectively. The vehicles were also instrumented to record stopping distances and decelerations from on-road stopping tests performed from 32.2 km/hr. In general, nearly all of the PBBTs were able to accurately measure the CVs' brake forces. Only one of the FP-type testers experienced erratic performance during the round robin. In contrast several of the PBBTs had difficulty in reporting the accurate gross vehicle weight. In some cases, particularly with the portable PBBTs the reported wheel loads for axles 2 and 4 (the lead axle on the tandem set) of the 5-axle vehicle were very high, leading to an under-prediction of the vehicle deceleration capability. Calibration checks of the PBBT weighing mechanisms indicated that all could meet the functional specifications. As such, it was concluded that accounting for the redistribution of axle loads due to the vehicle suspension and the geometry of the PBBT ramp would require special test procedures or remote entry of vehicle or axle weights for use in law enforcement. The repeatability of all the PBBTs was good, meeting the acceptability criteria in more than 93 percent of the test cases.
Publisher:
ISBN:
Category : Motor vehicles
Languages : en
Pages :
Book Description
This report documents the results of a series of tests in which several different types of performance-based brake testers (PBBTs) were compared side-by-side (i.e. a round robin test) in their ability to accurately measure brake forces (BFs) and wheel loads (WLs) of commercial vehicles (CVs), and to then predict the vehicle deceleration capability for a 32.2 km/hr on-road stopping test. The PBBTs consisted of five roller dynamometers (RD), two flat plate (FP) testers, and one breakaway torque tester (BTT). A PBBT that can also meet a set of functional specifications could be used for law enforcement by safety inspectors once performance-based criteria are codified. In the test program, specific ratios of BF to WL were imposed on both a 5-axle combination tractor semi-trailer and a two-axle straight truck, in both the fully laden and unladen conditions. In each loading condition, the overall vehicle braking capability was set to achieve a proposed minimum requirement of 0.4g, where g is the acceleration due to gravity. In addition, the brakes on specific individual wheels were set to provide a BF/WL of 0.25 and 0.35, for a steer and a non-steer wheel, respectively. The vehicles were also instrumented to record stopping distances and decelerations from on-road stopping tests performed from 32.2 km/hr. In general, nearly all of the PBBTs were able to accurately measure the CVs' brake forces. Only one of the FP-type testers experienced erratic performance during the round robin. In contrast several of the PBBTs had difficulty in reporting the accurate gross vehicle weight. In some cases, particularly with the portable PBBTs the reported wheel loads for axles 2 and 4 (the lead axle on the tandem set) of the 5-axle vehicle were very high, leading to an under-prediction of the vehicle deceleration capability. Calibration checks of the PBBT weighing mechanisms indicated that all could meet the functional specifications. As such, it was concluded that accounting for the redistribution of axle loads due to the vehicle suspension and the geometry of the PBBT ramp would require special test procedures or remote entry of vehicle or axle weights for use in law enforcement. The repeatability of all the PBBTs was good, meeting the acceptability criteria in more than 93 percent of the test cases.
Performance-based Brake Testers: Round Robin Final Report
Author: Steven J. Shaffer
Publisher:
ISBN:
Category :
Languages : en
Pages : 134
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 134
Book Description
Development, Evaluation, and Application of Performance-based Brake Testing Technologies
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 4
Book Description
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 4
Book Description
Federal Register
Author:
Publisher:
ISBN:
Category : Administrative law
Languages : en
Pages : 1048
Book Description
Publisher:
ISBN:
Category : Administrative law
Languages : en
Pages : 1048
Book Description
International Technical Conference on Experimental Safety Vehicles. Thirteenth. Proceedings. Volume I.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 764
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 764
Book Description
MVMA/NHTSA/SAE Heavy Truck Round Robin Brake Test
Author: R. C. Kempf
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
Real-Time Dynamic Brake Assessment Proof of Concept Final Report
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This proof-of-concept research was performed to explore the feasibility of using real-world braking data from commercial motor vehicles to make a diagnosis of brake condition similar to that of the performance-based brake tester (PBBT). This was done by determining the relationship between pressure and brake force (P-BF), compensating for the gross vehicle weight (GVW). The nature of this P-BF relationship (e.g., low braking force for a given brake application pressure) may indicate brake system problems. In order to determine the relationship between brake force and brake application pressure, a few key parameters of duty cycle information were collected. Because braking events are often brief, spanning only a few seconds, a sample rate of 10 Hz was needed. The algorithm under development required brake application pressure and speed (from which deceleration was calculated). Accurate weight estimation was also needed to properly derive the braking force from the deceleration. In order to ensure that braking force was the predominant factor in deceleration for the segments of data used in analysis, the data was screened for grade as well. Also, the analysis needed to be based on pressures above the crack pressure. The crack pressure is the pressure below which the individual brakes are not applied due the nature of the mechanical system. This value, which may vary somewhat from one wheel end to another, is approximately 10 psi. Therefore, only pressures 15 psi and above were used in the analysis. The Department of Energy s Medium Truck Duty Cycle research has indicated that under the real-world circumstances of the test vehicle brake pressures of up to approximately 30 psi can be expected. Several different types of data were collected during the testing task of this project. Constant-pressure stopping tests were conducted at several combinations of brake application pressure (15, 20, 25, and 30 psi), load conditions (moderately and fully laden), and speeds (20 and 30 mph). Data was collected at 10 Hz. Standard and stepped-pressure performance-based brake tests with brake pressure transducers were performed for each loading condition. The stepped-pressure test included the constant-pressure intervals of brake application at 15, 20, 25, and 30 psi. The PBBT data files included 10 Hz streaming data collected during the testing of each axle. Two weeks of real-world duty cycle (driving and braking) data was also collected at 10 Hz. Initial analysis of the data revealed that the data collected in the field (i.e., day-to-day operations) provided the same information as that obtained from the controlled tests. Analysis of the data collected revealed a strong linear relationship between brake application pressure and deceleration for given GVWs. As anticipated, initial speed was not found to be a significant factor in the deceleration-pressure relationship, unlike GVW. The positive results obtained from this proof of concept test point to the need for further research to expand this concept. A second phase should include testing over a wider range of speeds and include medium brake application pressures in addition to the low pressures tested in this research. Testing on multiple vehicles would also be of value. This future phase should involve testing to determine how degradation of braking performance affects the pressure-deceleration relationship.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This proof-of-concept research was performed to explore the feasibility of using real-world braking data from commercial motor vehicles to make a diagnosis of brake condition similar to that of the performance-based brake tester (PBBT). This was done by determining the relationship between pressure and brake force (P-BF), compensating for the gross vehicle weight (GVW). The nature of this P-BF relationship (e.g., low braking force for a given brake application pressure) may indicate brake system problems. In order to determine the relationship between brake force and brake application pressure, a few key parameters of duty cycle information were collected. Because braking events are often brief, spanning only a few seconds, a sample rate of 10 Hz was needed. The algorithm under development required brake application pressure and speed (from which deceleration was calculated). Accurate weight estimation was also needed to properly derive the braking force from the deceleration. In order to ensure that braking force was the predominant factor in deceleration for the segments of data used in analysis, the data was screened for grade as well. Also, the analysis needed to be based on pressures above the crack pressure. The crack pressure is the pressure below which the individual brakes are not applied due the nature of the mechanical system. This value, which may vary somewhat from one wheel end to another, is approximately 10 psi. Therefore, only pressures 15 psi and above were used in the analysis. The Department of Energy s Medium Truck Duty Cycle research has indicated that under the real-world circumstances of the test vehicle brake pressures of up to approximately 30 psi can be expected. Several different types of data were collected during the testing task of this project. Constant-pressure stopping tests were conducted at several combinations of brake application pressure (15, 20, 25, and 30 psi), load conditions (moderately and fully laden), and speeds (20 and 30 mph). Data was collected at 10 Hz. Standard and stepped-pressure performance-based brake tests with brake pressure transducers were performed for each loading condition. The stepped-pressure test included the constant-pressure intervals of brake application at 15, 20, 25, and 30 psi. The PBBT data files included 10 Hz streaming data collected during the testing of each axle. Two weeks of real-world duty cycle (driving and braking) data was also collected at 10 Hz. Initial analysis of the data revealed that the data collected in the field (i.e., day-to-day operations) provided the same information as that obtained from the controlled tests. Analysis of the data collected revealed a strong linear relationship between brake application pressure and deceleration for given GVWs. As anticipated, initial speed was not found to be a significant factor in the deceleration-pressure relationship, unlike GVW. The positive results obtained from this proof of concept test point to the need for further research to expand this concept. A second phase should include testing over a wider range of speeds and include medium brake application pressures in addition to the low pressures tested in this research. Testing on multiple vehicles would also be of value. This future phase should involve testing to determine how degradation of braking performance affects the pressure-deceleration relationship.
Vehicle Dynamics, Braking, Steering, and Suspensions
Author:
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 248
Book Description
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 248
Book Description
Development, Evaluation, and Application of Performance-based Brake Testing Technologies
Author:
Publisher:
ISBN:
Category : Motor vehicles
Languages : en
Pages :
Book Description
This report presents the results of the field test portion of the Development, Evaluation, and Application of Performance Based Brake Testing Technologies (PBBT) Project sponsored by the U.S. Department of Transportation's Federal Highway Administration. A PBBT is a device that can assess the braking capabilities of a vehicle through a quantitative measure of either individual brake and/or overall braking performance in a controlled test. Various first and second generation PBBTs designed for use with commercial motor vehicles were evaluated at roadside commercial vehicle inspection stations. The results were collect and analyzed and recommendations for the use of PBBTs was reported.
Publisher:
ISBN:
Category : Motor vehicles
Languages : en
Pages :
Book Description
This report presents the results of the field test portion of the Development, Evaluation, and Application of Performance Based Brake Testing Technologies (PBBT) Project sponsored by the U.S. Department of Transportation's Federal Highway Administration. A PBBT is a device that can assess the braking capabilities of a vehicle through a quantitative measure of either individual brake and/or overall braking performance in a controlled test. Various first and second generation PBBTs designed for use with commercial motor vehicles were evaluated at roadside commercial vehicle inspection stations. The results were collect and analyzed and recommendations for the use of PBBTs was reported.