Fuel Economy Analysis of a Tractor Trailer: Calculating Drag and Determining Fuel Economy, Study Guides, Projects, Research of Fluid Mechanics

Download Fuel Economy Analysis of a Tractor Trailer: Calculating Drag and Determining Fuel Economy and more Study Guides, Projects, Research Fluid Mechanics in PDF only on Docsity! Fuel Economy of A Tractor Trailer by Hieu Nguyen School of Engineering Grand Valley State University EGR 365 - Fluid Mechanics Section B Instructor: Dr. David Blekhman July 24, 2006 Problem Statement Calculate the total drag for tractor trailer, given direction and speed of travel and wind speed. Also, determine the fuel economy of the truck assuming constant speed, level roads, and no accessory power. Vehicle Parameters Tractor: Mack, cab over engine, non-sleeper Trailer: 13.5 feet, smooth sides Gap: 70 inches Engine: Mack ENDT 676 Accessory power: assume 0 Driveline efficiency, η: 0.85 Rear-end gear ratio: 4.17:1 Transmission gear ratio: 1:1 Weight: 53,780 lbf Tire radius: 21.25 inches Tire type, bias ply, worn: a = 7.5 lbf/1000 lbf, b = 0 Projected frontal area: 114.5 ft 2 Direction of travel was east at 65 mph on a July night with a 10 mph wind speed. Equations Used The following equations were used to determine the drag and fuel economy. The brake horsepower based on total drag, speed, driveline efficiency and accessory power was calculated using Eq. (1)
    (1) where BHP was the brake horsepower, DT was the total drag on the truck in pound-force, V was the truck speed in feet per second, nD was the driveline efficiency, and Pacc was the accessory power. Accessory power of the truck was assumed to be zero. The total drag on the truck was calculated using Eq. (2)        2  (2)