Commercial Vehicle Braking Systems e-Seminar

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Increased public pressure to improve truck safety and new government braking regulations for commercial vehicles have intensified the need to better understand the factors influencing heavy vehicle braking performance. In this e-Seminar, Instructor Leonard Buckman focuses on understanding medium-duty hydraulic brake systems and heavy-duty air brake systems and how both systems' performance can be predicted, maintained and optimized. He explains the function and application of the major brake system components and helps you to discover how brakes, tires and roadways interact as a system. Federal braking regulations for both hydraulic and air brake vehicles are also covered.

Based on the popular classroom seminar, this more than 21 hour course offers an overview, seventeen modules and course exercises accompanied by this handbook. The text, Commercial Vehicle Braking Systems: Air Brakes, ABS and Beyond, written by the instructor is included as a reference.

Major topics include:

• Overview[Total Run Time: 9 minutes]
  • Describe the major objectives of this seminar
  • List the primary factors that continue to drive the evolution of commercial vehicle brake systems
  • Specify the gross vehicle weight ranges used to describe classes of commercial vehicles and the type of brake system typically used for each class
• Brake Actuation Systems[Total Run Time: 1 hour, 28 minutes]
  • Explain the functionality of hydraulic brake actuation systems used on class 6 and 7 commercial vehicles
  • Identify the components that comprise the hydraulic brake actuation system
  • Recognize that small amounts of moisture in the hydraulic brake fluid result in major brake performance degradation
  • List the sub-systems that make up a vehicle's brake actuation system
  • Draw a tractor service and emergency brake actuation schematic
  • Troubleshoot a tractor or truck air brake actuation system using a brake schematic
  • Define the sub-systems that make up the air brake system
  • Describe why the truck emergency brake actuation system must be different from that of a tractor
• Major Air System Components [Total Run Time: 1 hour, 29 minutes]
  • Identify each component used in an air brake actuation system
  • Describe the functionality of each component of the actuation system
  • Explain how a relay valve speeds up air delivery to the brake chambers
  • Discuss the multiple functions of a spring brake chamber
  • List the four most common methods used to condition brake system compressed air
• Trailer Air Actuation Systems and Components[Total Run Time: 35 minutes]
  • Describe the functionality of each of the components of a trailer air brake system
  • Troubleshoot a trailer air brake system using a brake schematic
  • Differentiate a protected reservoir trailer system (PR), a spring brake priority system (SBP) and a service brake priority system (SRP) and explain the advantages / disadvantages of each
  • Realize that a trailer air brake system has a single service brake system whereas a truck and tractor actuation system must have a dual service system for emergencies
• Foundation Brakes [Total Run Time: 2 hours, 9 minutes / 40 minutes]
  • Explain the operation of air cam brakes, air wedge brakes, air disc brakes and hydraulic disc brakes.
  • Describe the advantages / disadvantages of each of the different types of foundation (wheel) brakes
  • Explain why brake adjustment is so critical particularly with air actuated cam brakes
  • Compare a "clearance sensing" and a "stroke sensing" automatic slack adjuster
  • Explain why North American class 8 trucks and tractors have been slow to accept air disc brakes despite more than 95% usage in Europe
  • Describe temperature fade, mechanical fade and water fade of brakes
  • List the fundamental characteristics of a good brake lining
  • Recognize the limitations of the brake lining edge code as a means for selecting replacement brake linings
• Braking Performance Fundamentals[Total Run Time: 1 hour]
  • Describe how vehicle load and speed affect vehicle stopping distance
  • Calculate the:
    • Braking force developed given the tire rolling radius and the brake torque
    • Maximum braking force possible at the tire to road interface
    • Amount of heat generated in stopping a vehicle
    • Stopping distance of a vehicle
  • Degradation of vehicle stopping performance due to hot and/or out of adjustment cam brakes
• Maintenance [Total Run Time: 1 hour, 23 minutes]
  • Explain why air brake performance is so sensitive to brake adjustment
  • Describe the proper technique for measuring cam brake adjustment
  • Analyze the relationship of chamber pushrod force to pushrod travel
  • Identify the difference between brake drum / rotor scoring and heat checking
  • Name the potential sources of premature brake lining wear
• Brake Force Distribution [Total Run Time: 50 minutes]
  • Define brake "balance" and list the impacting factors
  • Discuss the differences in commercial vehicle brake balance philosophy between the US and Europe and the resulting difference in performance.
  • Calculate friction utilization and determine at what point a wheel will lock during braking
  • Define braking efficiency
• Vehicle Dynamics and Tires[Total Run Time: 30 minutes]
  • Compare tire longitudinal force vs. lateral slip capability.
  • Recognize the inaccuracy of using passenger car tire coefficient of friction for predicting commercial vehicle brake performance.
  • Recognize how tire normal load affects tire coefficient of friction.
  • Describe the vehicle response resulting from locking wheels on the different axles of the combination vehicle
  • Compare the effectiveness of ABS to so-called "anti-jackknife" devices in preventing combination vehicle jackknifing
• Thermal Considerations[Total Run Time: 22 minutes]
  • Calculate the horsepower required to stop a vehicle on any road grade from any road speed.
  • Discuss the relative contribution of each source of vehicle retardation in bringing a vehicle to a stop.
  • Compare the drag and thermal capacity of a commercial vehicle to that of a passenger car.
  • Discuss the pros and cons of using the snub procedure vs. the low pressure steady application procedure in descending long, steep grades with a combination vehicle
  • Relate why disc brakes do not suffer from mechanical fade
• Tractor-Trailer Brake System Compatibility[Total Run Time: 20 minutes]
  • Explain why having "good" brakes on both the tractor and the trailer does not insure "good" combination vehicle braking performance
  • Describe the factors that affect combination vehicle imbalance
  • Recognize how slight differences in valve threshold pressures can result in significant temperature differences between tractor and trailer brakes
  • Discuss how poor tractor-trailer balance can impact the performance and cost of operation of the combination vehicle
• Antilock Brake Systems (ABS)[Total Run Time: 2 hours, 12 minutes / 45 minutes]
  • State the objectives of ABS and the principles of operation
  • Identify and describe the function of each major ABS component
  • Compare the performance of different ABS sensor and modulator configurations (4S/4M, 6S/6M, etc)
  • Compare the performance of different ABS control philosophies on road surfaces such as asphalt, ice and split coefficient
  • Analyze the control philosophy of a typical ABS algorithm
  • Describe a typical approach to fault detection and system fail safe logic
  • Discuss the issues involved in powering trailer ABS
  • Illustrate the functional differences between air ABS and hydraulic ABS
• Electronic Communication[Total Run Time: 23 minutes]
  • Summarize the role of data links in the development of commercial vehicle electronic control systems
  • Recount the evolution of electronic communication for commercial vehicles (SAE J1708, SAE J1587, SAE J1922 and SAE J1939)
  • Describe the usage of Power Line Carrier (PLC) for powering trailer ABS
• Automatic Traction Control (ATC)[Total Run Time: 34 minutes]
  • Describe how ABS can be expanded to provide vehicle traction enhancement
  • Identify and describe the components required to achieve the ATC function
  • Explain the basics of ATC wheel control and how they differ from ABS
  • Define the two modes of automatic traction control operation
  • Compare the performance of various ATC configurations relative to driver's best effort with and without mechanical inter-axle differential locks
  • Decide which traction enhancement method is best for a given vehicle duty cycle
• Electronically Controlled Braking Systems (ECBS)[Total Run Time: 48 minutes]
  • Discuss how future ECBS will replace pneumatic control of the braking process
  • List the advantages and disadvantages of using ECBS
  • Identify and describe the function of the components required for ECBS
• Electronic Stability Control (ESC) and Roll Protection (RSC)[Total Run Time: 53 minutes]
  • Describe the basic methodology used to maintain vehicle stability during rapid steering maneuvers
  • Illustrate the roll protection algorithm methodology used to determine impending roll and provide intervention to maintain stability
  • Explain how the vehicle's center of gravity and mass are estimated by the roll stability algorithm
• Brake Testing [Total Run Time: 54 minutes]
  • Describe the vehicle brake performance tests that are used to determine compliance to FMVSS 121
  • Identify the vehicle brake tests that are generally run by brake suppliers and vehicle manufacturers
  • Select the vehicle parameters (load, CG, tire rolling radius, etc) appropriate for brake testing of a specific class of vehicles
  • List the laboratory brake tests that are conducted by the industry and describe the objective of each
  • Review the advantages and limitations of vehicle roller brake testers in evaluating in-service vehicle brake performance
• Brake Regulations [Total Run Time: 54 minutes]
  • Recognize the governmental agencies that regulate commercial vehicle brake performance.
  • Discuss how National Highway Traffic Safety Administration (NHTSA) and the Federal Motor Carrier Safety Administration (FMCSA) rules differ in application and enforcement.
  • Describe the rulemaking process used by the NHTSA in promulgating Federal Motor Vehicle Safety Standards such as FMVSS 121 - Air Brakes.
  • Describe the implications of self-certification for compliance to any FMVSS regulation.
  • Discuss the potential penalties for non-compliance to a FMVSS regulation
  • Examine the basic requirements of commercial vehicle brake regulations FMVSS 105 Hydraulic Brakes and FMVSS 121 Air Brakes

About the Instructor: Leonard C. Buckman
Leonard Buckman is president of Buckman Consulting Services, Inc., a firm with OEM and brake supplier clients in North America, Japan and Europe. Previously, he worked at Ford Motor Company as a brake specialist, heading up all heavy truck brake system design actions necessary for the initial implementation of FMVSS 121; at Rockwell International, serving as Chief Brake Engineer, Director of Worldwide Brake Engineering & Product Planning, and Vice President of Brake and Axle Product Management; and at Meritor WABCO VCS as President and General Manager. Mr. Buckman has a unique perspective because of his experience as a brake specialist both at a major truck OEM and at major suppliers of worldwide brakes and brake systems. He was selected by the U.S. Secretary of Transportation to serve as the commercial vehicle brake specialist on the 1999 DOT Vehicle Safety Planning Group and has twice received the SAE Distinguished Speaker Award. Mr. Buckman is a registered Professional Engineer and holds a B.S. in engineering physics from Michigan Technological University. He also completed post-graduate work in engineering mechanics and mechanical engineering at Wayne State University and the University of Michigan, respectively.

Is this e-Seminar for You?
This e-Seminar is geared toward engineers and technicians who are involved in the design, development and testing of heavy vehicle brakes. Fleet personnel involved with safety and brake system specification and maintenance, driver-trainers, and truck accident investigators will also find this course of value.

This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 2.2 Continuing Education Units (CEUs). Upon completion of this e-seminar, accredited reconstructionists should contact ACTAR, 800-809-3818, to request CEUs. As an ACTAR approved course, the fee for CEUs is reduced to $5.00.

About e-Seminars
SAE "e-Seminars" are electronically delivered seminars featuring full-motion video illustrated with synchronized presentation slides. e-Seminars are based on some of SAE's most highly attended and rated classroom seminars.

Convenient & Portable Learning
Convenient and portable, SAE e-Seminars offer a new way to receive the same instruction as live classroom learning without the expense of travel and time away from the workplace. Using a laptop or PC with an Internet connection, you can view individual modules at your own pace, at times convenient to you. You can even e-mail your questions to SAE for instructor reply.

• 365 days of access (from date of purchase) to the 21 hour course
• Links to streaming video modules
• Course Handbook (downloadable, .pdf's, subject to DRM)
• Online Pre-test (self-test, immediate results)
• Online Post-test (submit to SAE)
• 2.2 CEUs*/Certificate of Achievement (with satisfactory post-test score)
• The book, Commercial Vehicle Braking Systems: Air Brakes, ABS and Beyond, by Leonard C. Buckman (downloadable, .pdf)

Equipment Requirements

• Windows 2000, XP, 7 (Not currently supported by Windows Vista)
• Pentium III PC
• Minimum 128 MB RAM; recommended 256 MB RAM
• Internet Explorer 6.0 & above browser (Mozilla Firefox, Google Chrome, and Unix/Linus based browsers are not currently supported)
• Adobe Flash Player 8.0 & above
• Broadband-128Kbps and above
• 1024 X 768 Screen Resolution
• Sound Card/Speakers

Available in Single-User packages. Quantity discounts for three or more students and Site License options also are available - complete a Corporate Learning Solutions Request Form for a quote.

For more detail, email CustomerService@sae.org; or call
1-877-606-7323 (U.S. and Canada) or 724-776-4970 (outside US and Canada).