Citation

Amlin E, Bradley AH. Proc. Int. Tech. Conf. Enhanced Safety Vehicles 1992; 1992: 439-441.

Copyright

(Copyright © 1992, In public domain, Publisher National Highway Traffic Safety Administration)

DOI

unavailable

PMID

unavailable

Abstract

A variable tire pressure control system, otherwise referred to as central tire inflation (CTI), allows the tire inflation pressures on a heavy vehicle to be changed from the operator's compartment while the vehicle is in motion. Depending on the application, a number of preprogrammed inflations are available that match tire pressures to the load, road type, vehicle speed, and road strength. The objectives of this study were: (a) determine the degree of off-highway traction improvement that may be realized by applying this technology, (b) evaluate, in conjunction with the tire manufacturer, the effects of variable inflation pressures on tire life and tire casing suitability for recapping, (c) compare the productivity and costs of the CTI- equipped truck with those of the control fleet, and (d) demonstrate this technology to the Canadian forest industry. The in service evaluation began in October 1990 with the installation of CTI hardware onto the truck for controlling only the tires on the two driven axles. Each driver was given a log book in which to note any tire or rim damage, tire mileage, tire pressure and any changes in vehicle handling occurring as a result of using CTI. Load content, weather and road conditions were also recorded, as were costs, relevant repairs or maintenance. The evaluation lasted one year. A special test procedure was set up to evaluate traction improvement. This consisted of a loaded truck attached to a loaded tractor-pull sled. The procedure consisted of the truck pulling the sled forward until the truck broke traction. Three or more test pulls were conducted at each of the CTI systems normal operating pressures. At the point of complete traction loss or spinout, both the distance pulled and the drawbar force were measured. Results from the traction improvement indicate that CTI technology offers significant traction improvements which should improve truck gradeability, travel speed and ride. The in service tests indicate that CTI improved tire wear rates at no extra cost in maintenance or down time.