Liquid Cooled Driveline Braking System Technology and Test Results 2010-01-1703

It is well known that heat generated during vehicle braking affects wear and stopping distances. To improve these conditions, supplemental retarders, such as exhaust brakes on diesel powered trucks and electromagnetic retarders have been used for years. Several of the diesel engines (below 7 Liters) are no longer designed to allow the use of exhaust brakes, and gas powered vehicles do not have that option either. Other options such as electromagnetic retarders are heavy, draw excessive amounts of current, and are a costly installation.

To fill the void left by the elimination of exhaust brakes from some of these vehicles, and to provide an option that improves upon the undesirable aspects of electromagnetic retarders, a new technology; Liquid Cooled Disc Brakes, has been developed and designed into a product that fits on most popular truck chassis in the Class 2 - 4 range. The current application of this technology is as a supplemental driveline brake, or a retarder, mounted to the rear of the transmission. The new design utilizes a transfer case to move the brake off center of the driveline, keeping the original driveshaft length in most cases. This paper will describe the technology, the design of the particular product that was tested, test results and the equations used to calculate the power absorbed by the product. Both downhill and flatland braking test results will be presented at various GVW's on a vehicle that is representative of applications such as midsize work trucks, shuttle buses, motorhomes, etc. The positive impact that the device had on the brake temperatures, thermal degradation and stopping distances, as well as implications for future development will be divulged in the conclusions.