Exam 2 B	Automotive Engineering I	2nd semester of 1428-29
Student Name:                                                                        Student Class No.:

 

1) A- What are the functions and types of the following units of the transmission?

	Functions	Types
Propeller shaft	- -	- -
Axle	- -	- -

 

1) B- If the input to gear A is equal to:

 N_input = N_A= 5000 rpm, T_input = T_A= 180 N.m, h_g= 90%.

Find:

A) The 2^nd gear ratio

B) The T_output at 2^nd gear

C) The P_in

2) A- What is the difference between the following:

- ¾ floating axle & fully floating axle

 

 

 

 

 

- Two speed axle & double reduction axle

 

 

 

 

 

 

2) B- A car has the following specifications

Ne (rpm)	2000	Find (at engine speed of 2000 rpm) the following: a- axle shaft torque (Tw)dd at direct drive (1:1), b- car speed (v)g2 on second gear, c- car tractive effort (TE)dd at direct drive.
Te (Nm)	120
Gear box  ig	3.91, 2.17, 1.37, 1.00
hg	90%
Final drive if	3.46
hf	95%
rw (m)	0.32

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

 

 

3) A- What are the factors affecting the air drag coefficient (C_d)

 

 

 

 

 

3) B- i: In which case of the following would the car be faster? Case a or case b

Case (a)	Case (b)
with a final drive ratio (if) of 4.21	with a final drive ratio (if) of 3.85
with a velocity (v)of 30 m/s	with a velocity (v) of 30 km/h

ii- and why:

-

-

           

3) C- A car having the following characteristics:

- car mass (m) of 1200 kg.

- car frontal area (A_f) 2.4 m²

- car coefficient of air resistance (C_d) (0.4).

- coefficient of wheel rolling resistance (f_r) is 0.02

and the air density (r) is 1.2 kg/m³, Find:

a) the car air resistance (AR) at a car speed (v) of 120 km/h.

 

 

 

 

 

 

b) the car air resistance (AR) at a car speed (v_car) of 120 km/h and a tail wind speed (v_air) of 30 km/h.

 

 

 

 

 

 

c) the rolling resistance (RR).