Search Results

An analysis of antilock brake system dynamics, based on nonlinear control theory, was performed. Results were used to define initial performance and design requirements for a prototype fluidic motorcycle antilock system. The analysis emphasized the frequency response of system components and effects on stopping performance and stability. Results showed wheel angular acceleration provides a feasible single loop feedback for antilock control; wheel angular jerk is probably not a desirable primary feedback variable; nominal design requirements for modulator and controller exist that represent a compromise among high and low μ performance, stability, roughness, and signal-to- noise ratio; net time delay between modulator and brake caliper is a key design parameter and should be investigated more thoroughly.

Abstract Brake squeal reduces comfort for the vehicle occupants, damages the reputation of the respective manufacturer, and can lead to financial losses due to cost-intensive repair measures. Mode coupling is mainly held responsible for brake squeal today. Two adjacent eigenfrequencies converge and coalesce due to a changing bifurcation parameter. Several approaches have been developed to suppress brake squeal through structural changes. The main objective is to increase the distance of coupling eigenfrequencies. This work proposes a novel approach to structural modifications and sizing optimization aiming for a start at shifting a single component eigenfrequency. Locations suitable for structural changes are derived such that surrounding modes do not significantly change under the modifications. The positions of modifications are determined through a novel sensitivity calculation of the eigenmode to be shifted in frequency.

The fully decoupled brake by wire system is a complex system consisting of mechanical components such as springs and rubber and hydraulic structural components coupled together. Compared to conventional braking systems, it is characterized by the full decoupling of the brake pedal from the brake wheel cylinders in normal braking mode, and the pressure fluctuations in the wheel cylinders do not affect the pedal feel. In order to predict brake pedal feel in a passenger car, a dynamic model was developed for both normal and backup braking modes, taking into account the variation of the volume modulus of the brake fluid and the frictional forces of the master cylinder pistons. The influence of different pedal input speeds on the pedal feel characteristic curve was analyzed using static vehicle tests and the related parameters of the braking system were identified in order to correct the design data.

De-centralized brake actuation – that is, brake systems that incorporate individual actuators at each wheel brake location to both provide the apply energy and the modulation of braking force – is not a new area of study. Typically realized in the form of electro-mechanical brake calipers or drum brakes, or as “single corner” hydraulic actuators, de-centralized actuation in braking systems has already been deployed in production on General Motor EV1 Electric Vehicle (1997) in the form of electric drum brakes and has been studied continually by the automotive industry since then. It is frequently confused with “brake by wire,” and indeed practical implementations of de-centralized actuation are a form of brake by wire technology. However, with millions of vehicles on the road already with “brake by wire” systems - the vast majority of which have centralized brake actuation – the future of “brake by wire” is arguable settled.

Over the next decade, CO2 legislation will be more demanding and the automotive industry has seen in vehicle electrification a possible solution. This has led to an increasing need for advanced powertrain systems and systematic model-based control approaches, along with additional complexity. This represents a serious challenge for all the OEMs. This paper describes a novel reverse engineering methodology developed to estimate relevant powertrain data required for fuel consumption-oriented hybrid electric vehicle (HEV) modelling. The estimated quantities include high-voltage battery internal resistance, electric motor and transmission efficiency, gearshift thresholds, torque converter performance diagrams, engine fuel consumption map and front/rear hydraulic brake torque distribution. This activity provides a list of dedicated experimental tests, to be carried out on road or on a chassis dynamometer, aiming at powertrain characterization thanks to a suitable post-processing algorithm.

Among the performance concerns in brake design, drag and fluid displacement are getting more attention in the requirement definition. High drag not only affects fuel efficiency and lining life, it is also a contributing factor to rotor thickness variation and brake pulsation. In this paper, a system approach to drag performance of a disc brake caliper is presented. A one-dimensional simulation model, which considers all the significant factors, including lining stiffness and hysteresis, housing stiffness, seal/groove characteristic, and stick-slide behavior between the seal and piston, is developed to capture the interactive impact of each parameter to caliper drag performance. The system model is validated with experimental measurements for caliper fluid displacement and piston retraction. A parameter study is then conducted to investigate the component interactive impact to the drag performance.

This report has been compiled by the Landing Gear Systems Terminology panel of SAE Committee A-5 (Aerospace Landing Gear Systems). It represents an effort to gather together those terms commonly used within the discipline.

This SAE Recommended Practice identifies and defines terms specifically related to brake systems.

This standard documents dimensional metric specifications for hydraulic brake system tubing with flared ends, threaded ports, and male tube nuts for the interconnection of major components in automotive hydraulic brake systems. The purpose of this document is to recommend preferred metrically dimensioned components (including alternative choices), that are intended to be functionally compatible with International Organization for Standardization Specification, ISO 4038-1977 (E). Some applications may require sizes of forms other than those shown herein, and this document does not preclude such other details when they are required.

This recommended practice documents dimensional metric specifications for hydraulic brake system tubing with flared ends, threaded ports, male tube nuts, and banjo bolts for the interconnection of major components in automotive hydraulic brake systems. Banjo blocks are not covered by this recommended practice. The purpose of this document is to recommend preferred metrically dimensioned components, (including alternative choices) that are intended to be functionally compatible with International Standard Organization Specification ISO 4038-1977 (E). Some applications may require sizes or forms other than those shown herein, and this document does not preclude such other details when they are required.

This recommended practice documents dimensional metric specifications for hydraulic brake system tubing with flared ends, threaded ports, and male tube nuts for the interconnection of major components in automotive hydraulic brake systems. The purpose of this document is to recommend preferred metrically dimensioned components (including alternative choices), that are intended to be functionally compatible with International Organization for Standardization Specification, ISO 4038-1977 (E). Some applications may require sizes or forms other than those shown herein, and this document does not preclude such other details when they are required.

The current document is a part of an effort of the Active Safety Systems Committee, Active Safety Systems Sensors Task Force whose objectives are to: a Identify the functionality and performance you could expect from active safety sensors b Establish a basic understanding of how sensors work c Establish a basic understanding of how sensors can be tested d Describe an exemplar set of acceptable requirements and tests associated with each technology e Describe the key requirements/functionality for the test targets f Describe the unique characteristics of the targets or tests This document will cover items (a) and (b).

Caused by a number of beneficial properties inherently from the zinc-nickel material, this electrodeposited alloy is used more and more for cathodically protecting layers on ferrous components like cast iron brake calipers. Direct plating from acidic solutions is the state-of-the-art solution for zinc-nickel surface finishing of these components. To contribute to the continuous improvement of the final component and reduce the finishing cost, areas for improvement have been scrutinized in a current finishing system. Areas for improvement have been identified in the uniformity of the nickel distribution within different current densities and in the handling and economy of the metallic zinc anodes used for zinc metal replenishment. While today’s acidic zinc-nickel electrolytes suit and usually exceed the requirements for an alloy containing 10-15% nickel, nickel incorporation may drop just below 12% incorporation rate in areas which are plated at high current densities.

This SAE Aerospace Recommended Practice (ARP) defines impulse test procedures that are recommended for hydraulic components.

This procedure provides test performance requirements for service, spring applied parking, and double diaphragm combination air brake actuators with respect to durability, function, and environmental performance when tested in accordance to SAE J1469.

This SAE Recommended Practice provides procedures and methods for testing service, spring applied parking, and combination brake actuators with respect to durability, function, and environmental performance. A minimum of five test units designated A, B, C, D, and E are to be used to perform all tests per 1.1 and 1.2.

This SAE Recommended Practice provides procedures and methods for testing service, spring applied parking, and combination brake actuators with respect to durability, function, and environmental performance. A minimum of five test units designated A, B, C, D, and E are to be used to perform all tests per 1.1 and 1.2.

This SAE recommended practice provides procedures and methods for testing service, spring applied parking and combination brake actuators for air disc brake applications. Methods and recommended samples for testing durability, function and environmental performance are listed in 1.1 and 1.2.

This SAE recommended practice provides procedures and methods for testing service, spring applied parking and combination brake actuators for air disc brake applications. Methods and recommended samples for testing durability, function and environmental performance are listed in 1.1 and 1.2.

Deltalloy™ 4032 has been developed to eliminate anodizing in applications which have been typically anodized for wear resistance. The combination of silicon and nickel in an aluminum matrix results in exceptional wear resistance. This product is available in screw machine stock form along with selected squares and rectangles. Deltalloy 4032 has already replaced 6262 and 2024 hard coat anodized parts in automotive steering column, brake master cylinder and transmission applications. This alloy can offer cost savings for potential users by eliminating anodizing. In particular, cost savings are realized by eliminating hard-coat anodizing, lower work-in-process inventories and the elimination of secondary grinding after hard-coat anodizing. Information is given on structure, mechanical properties, wear and durability testing along with machinability. In addition, data will be presented on salt spray corrosion testing.