Most brake component makers conduct field testing with actual police fleets. This type of fleet testing varies widely. In some cases, it involves supplying a police department brake pads and/or rotors, and the department installs the parts on regular patrol units while keeping detailed maintenance records. In other cases, the parts are used in a more specialized, accelerated-wear manner, like on the cars used for EVOC training.
In addition to their own internal performance and wear tests, as well as independent lab dynamometer testing, Affinia Global Brake and Chassis does police field testing with its Raybestos® brand of brake components. One of the police departments used for Raybestos beta-site testing is the Ingham County (Lansing), MI Sheriff’s Office.
Ingham County conducts some of its EVOC training on the infield road course and main oval of Michigan International Speedway
located an hour south of Lansing. MIS provided $225,000 of track rental, at no charge, to law enforcement agencies in 2008, and more than $1 million of complimentary track rental since the speedway began hosting police training in 2000.
In addition to the Ingham County Sheriff, law enforcement agencies in Jackson and Lenawee counties have used the track for pursuit training and classroom work in 2008. Ingham County has used the super speedway for two-day pursuit driving classes every September and October for the past eight years.
The Ingham County Sheriff operates a fleet of 32 Chevrolet Impalas and six Tahoes. Steve DeKett, Ingram County fleet administrator and master mechanic, has a long history of vehicle maintenance and is currently an active crew chief in road racing. DeKett was one of the moderators for the Medium / Large (50 or more vehicles) and County Police and Sheriff’s Departments agency networking dialogue session at the 2008 Police Fleet Expo
While severe-duty brakes have been available for years from Affinia-Raybestos, in October 2006, a new unique product line was formed: Raybestos
brand Police Patrol / Pursuit Friction brake pads. These products feature a distinct packaging and bear a Law Enforcement product logo. As part of the Affinia Group, these brakes are produced by Brake Parts Inc., with manufacturing facilities throughout North America.
As in the past, this year Affinia sent a team of product engineers to Ingham County to witness the training and to collect data. These efforts have produced a state-of-the-art line of products designed for police and emergency vehicle friction. In 2009, the Raybestos® brand Police-specific brake system products will include rotors, high-temperature calipers and D3EA® PPSV® certified pursuit-rated brake pads.
Raybestos® brand Police Friction also features Quiet on Arrival™ (QOA) technology. Known as a radio code used by some officers, “QOA” alerts any officer arriving on the scene that they need to remain quiet when arriving at a call location. With rubber-coated quiet clips and noise, vibration and harshness (NVH) control technology, Raybestos brand Police Friction assures that officers will arrive quietly.
In August 2008, the Police Patrol / Pursuit pads were Dual Dynamometer Differential Effectiveness Analysis (D3EA), Police and Public Service Vehicle (PPSV) certified. D3EA PPSV Certification is the only voluntary, objective and completely independent validation process for replacement brake friction materials and rotors that provides a basis for maintaining compliance with new vehicle Federal Motor Vehicle Safety Standards (FMVSS) requirements.
D3EA PPSV Certification uses independently administered, state-of-the-art dual-end brake dynamometer testing conducted at Greening Testing Laboratories Inc. (GTL) in Detroit, MI. As stated in Greening’s D3EA PPSV Test Guidelines, “PPSV certification captures the critical system level performance characteristics of police and other emergency service vehicles and has established performance requirements that may surpass those imposed by Original Equipment Manufacturers (OEMs).”
“Speed Rated” PPSV products have been subjected to performance requirements of FMVSS 135. This test also includes high-speed sections, utilizing a dual-ended dynamometer evaluation protocol replicating the actual vehicle testing sequence utilized by the original equipment (OE) manufacturers. The PPSV test sequence replicates the high-speed braking events used in new vehicle evaluations, like those performed by the Los Angeles County Sheriff and features time and distance controlled sequencing.
Replacement brake parts bearing the “Speed Rated” PPSV seal have met stringent, objective requirements for effectiveness, fluid displacement and service brake pedal force gain (pedal force and pedal travel) while being exposed to operating temperatures exceeding 1470 deg F. Proven OE-equivalent
Greening Testing Laboratories was the independent lab that conducted the compliance testing. According to Affinia-Raybestos, achieving this certification makes its product “OE equivalent.”
Affinia-Raybestos is not an OE brake component supplier to the domestic automakers for their police vehicles. This raises a significant spec-writing issue, an issue shared by nearly all aftermarket brake component manufacturers. Because they are not an OE supplier, they cannot bid on requests for quote that specify “OE” brake components. However, they can bid on “OE-equivalent” brake components, so they urge that the specs to be written that way.
Police fleet managers and brake pad spec writers need to know that only Raybestos and ACDelco aftermarket police pads meet the High-Speed section of FMVSS and are so certified. These tests preserve compliance with FMVSS 135.
The D3EA Certification Seal appears only on replacement friction materials, which meet platform-specific criteria. This testing provides the installer and the consumer with an objective basis for deciding which friction materials should be installed on a given vehicle. The Police Patrol / Pursuit pads are available for the 2003-2009 Ford CVPI, 2006-2009 Chevy Impala, 2006-2009 Dodge Charger and 2007-2009 Chevy Tahoe.
Like most aftermarket brake component manufacturers, Affinia-Raybestos develops its brake pads in at least three different steps. The makers start with internal testing, which includes performance against formal brake test protocols conducted in a lab environment. Here they can isolate variables and precisely measure subtle differences between friction materials.
Tests run on the brake dynamometer include standardized Federal Motor Vehicle Safety Standards (FMVSS) tests and specialized tests like the Los Angeles County Sheriff Pursuit Simulation test. Then pads are put on real cars and run on real roads. “People don’t drive dynos,” said Charles Darsey, test manager at the Affinia Research and Development.
In some cases, this on-vehicle testing is accelerated by testing on road racing tracks and EVOC courses. Sometimes this testing is done in fully instrumented vehicles that measure and record dozens of braking parameters. In other cases, this is a long-term, in-service, fleet test lasting many thousands of miles. The test results are relayed to the R&D lab friction formulation team to continuously improve the product and the testing protocol. The goal is to have the dynamometer testing duplicate reality as closely as possible.
One of the many Affinia-Raybestos test vehicles was on display at the Ingham County brake evaluation. This Ford CVPI is instrumented with $50,000 in data acquisition equipment. The CVPI’s on-board instruments measure pad temperature at all four wheels, line pressure at all four wheels, brake pedal effort (pounds), brake pedal travel (inches), and rate of deceleration. The instruments also measures noise, harshness and vibration, so if the brakes squeak or if components pulsate during braking, that is recorded.
The Impalas used during the Ingham County EVOC training were fitted with a number of different brake pads. One used the current generation Police Patrol / Pursuit pad. The other vehicles were fitted with various prototype formulas currently under development for vehicle evaluation.
“The opportunity for the Raybestos® product managers and R&D engineers to drive identical vehicles equipped with different pad compounds and rotors back-to-back provides critical feedback,” said Charles Darsey, test manager at Affinia’s Research and Development Center in Lexington, KY.
The manufacturing world is all about continuous improvement. This is especially true for automotive components that are complex compromises like tires and brake pads. The brake pads from both the manufacturer and the major aftermarket companies constantly improve, with changes sometimes occurring every year. Raybestos engineers are constantly developing higher performance brake components.
As a control or reference point, one of the Impalas on the training course was fitted with OE brake pads. Affinia-Raybestos starts with the OE brake pad to benchmark braking performance and pad wear. In side-by-side testing against, the OE pad on the pursuit course, Raybestos police pads exhibited either identical or improved performance.
Products Under Development
Affinia-Raybestos considers the braking system on a police vehicle as exactly that—a system. Braking is not just about the friction material in the brake pads. The system includes the pads, the rotor and the caliper. Affinia-Raybestos has just launched a new, police-specific rotor design to the market.
This police rotor is unique and incorporates Advanced Technology™ features. Among the design enhancements, police rotors are designed with proprietary internal vane geometry for better cooling and feature unique damped iron metallurgy for NVH control. The police rotor is mill balanced and coated with a special corrosion-resistant material.
The latest development news from Raybestos is a police-specific brake caliper with high temperature tolerant boots and heat-isolated components. This police caliper is currently available for the 2003-2009 Ford CVPI and the 2006-2009 Dodge Charger.
Ceramic Pads Run Hot
Most original equipment police-package brake pads use semi-metallic friction compounds rather than ceramic pads for a very good reason. Semi-metallic brake pads transfer heat much better from the braking system and run much cooler than ceramics. As a result, when driven hard, cars with ceramic pads generate enough heat to cause a number of brake-related problems. “When looking for performance, it is a semi-metallic pad,” said Terry Heffelfinger, director of product engineering, Affinia Global Brake & Chassis.
However, ceramic pads have certain advantages. They are almost dust-free, operate more quietly, and can have a long pad life under some driving conditions. Affinia-Raybestos has developed the High Performance ceramic pad. In fact, one of the Impalas being driven during the Ingham County training course was equipped with this High Performance ceramic pad and is available as an option for police fleet managers. This is just a small part of the 1 million miles of fleet field testing that Affinia-Raybestos has put into its line of brake pads.
Ed Sanow is the editorial director of Police Fleet Manager magazine. He can be reached at firstname.lastname@example.org.