Exam. 1-B Automotive Engineering II 1st semester 1428-1429 Student Name: Student No. 101-      -

1- A) Define the following:

a- Coefficient of air resistance (air drag coefficient)- Cd

b- Car wheel base (b)

c- Car inertia resistance (IR)

d- Lateral stiffness (Ca)

e- Tail wind

f- Neutral Steer

2- A) Draw the FBD of a car of mass (m), moving up hell having a slope (θ)o, if the car has a wheel base (b), and the height of the center of gravity (CG) is (h) m from the ground, and (x) m behind the front axle.

b) Find the weight on the front and rear axles (Wf, Wr), if:

 m 1200 kg θ 10o b 3.2 m h 0.6 m x 1.2 m

3- A) A car has mass (m) 1300 kg, and coefficient of rolling resistance (fr) of 0.018, and a frontal area (Af) of 2.0 m2. If  its drag coefficient (Cd) is 0.5, and the air density (ρ) is 1.2 kg/m3. The car velocity at maximum tractive effort at direct drive is 81 km/h.  Find

a- The rolling resistance of the car (RR)

b- The air resistance of the car (AR), if it is moving against wind (head wind) of 9 km/h

c- The maximum acceleration (a) in this condition if the maximum tractive effort (TE) at that velocity is 1200 N.

4- Find the inner angle (δi) of steering if the outer steering angle (δo) is 20o, for a perfect steering for a car having a wheel base (b) of 3.6 m and a track (t) of 1.8 m.