Automotive Engineering II                           Exam. 2

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1- A) Define the following عرف التالي:

i- Yaw motion

ii- Track circle diameter (D_s)

iii- King pin inclination (KPI, SAI)

iv- Steering ratio

B) Traction Control System (TCS, ASR):

What is it?

How it works?

Parts (components)

 C) Caster angle:

What is it?

Its function:

The problems if not correctly adjusted

D) What are the factors that lead to car under steer?

2) Find the inner angle of steering front wheel (d_i), if the car track (t) is 1.80 m, and the car wheel base (b) is 3.2 m, the outer steering angle (d_o) = 18^o. Where: cot d_o – cot d_i = t/b

3) A passenger car has a weight (w) of 20 kN, and a wheel base (b) of 3.2 m. The weight distribution on the front axle is 60% and that on the rear axle is 40% under static conditions. If the cornering

stiffness of each of the front tires (C_{a f})  is 37 kN/rad and that of the rear tires (C_{a r} ) is 36 kN/rad. Where the steer angle is

 i) Find the under steer coefficient (K_us). Dose the car have (neutral, under, over steer)?

ii) Find the steer angle (d) if the car has neutral steer, when it is negotiating a curve (R) of 24 m, at a velocity (v) of 72 km/h.

4) A car has a weight (w) N, and a wheel base (b) m, the CG is (x) m behind the front axel and (y) m in front of the rear axle, and (h) m above ground. Find:

 i) Front wheel reaction (R_f)

ii) the transferred weight (w_t) due to acceleration (a), and the front wheel force (F_f).

iii) the maximum acceleration if the car is FWD, and the adhesion coefficient is (m).