This preview shows pages 1–12. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: The Pennsylvania State University Department of Civil and Environmental Engineering CE 321: Highway Engineering Class #7: Tractive Effort and Vehicle Acceleration Spring 2008 Overview Available tractive effort How much can the engine generate? How much can the tire/road deliver? Vehicle acceleration Maximum Tractive Effort At some point, the engine can develop additional power beyond which can be supported by the pavement / tire interface. At this point, the additional power will merely spin the wheels. No vehicle acceleration. Available Tractive Effort 1 2 Available Tractive Effort f r mah To Calculate W r L Wh mah Wl h R W g g f a r sin cos + + = Available Tractive Effort f r mah To Calculate W f L Wh mah Wl h R W g g r a f sin cos += Looking Back and Substituting L Wh mah Wl h R W g g f a r sin cos + + = YIELDS ) sin ( g a f r W ma R L h W L l W + + + = Looking Back and Substituting g rl a R R R ma F + + + = Eq. 2.2 RECALL YIELDS g a rl R R ma R F + + =) sin ( g a f r W ma R L h W L l W + + + = ) ( rl f r R F L h W L l W+ = For a Rear Wheel Drive Car r W F = max ) ( rl f r R F L h W L l W+ = = L h L h f l W F rl f MAX 1 ) ( For a Front Wheel Drive Car + + = L h L h f l W F rl r MAX 1 ) ( Example Problem 1 A 2,500 lb car is at rest. It has a 120inch wheel base. The center of gravity is 40inches above the pavement and 40inches behind the front axle. What is the maximum tractive effort if: a) the car is front wheel drive, b) the car is rear wheel drive....
View
Full
Document
This note was uploaded on 06/08/2009 for the course CE 321 taught by Professor Petrucha during the Spring '02 term at Pennsylvania State University, University Park.
 Spring '02
 Petrucha
 Environmental Engineering

Click to edit the document details