Automotive Engineering I	Take Home Exam	(2)
Student Name:		Student Class No.

أتعهد أنا الطالب:                                                         والموقع أدناه بأن إجابة هذا الامتحان هي مجهودي الشخصي, وأني لم أشارك المعلومات مع أي من الطلاب الآخرين. 

                                                                                                              التوقيع

1- What factors leads to increase the following

2	1
		TE
		V
		AR
		RR
		GR
		IR
		Cd
		ρ
		fr

2- A car has the following: car mass (m) of 1100 kg, fontal area (A_f) of 2.1 m², rolling radius (r_w) of 0.32 m, total mechanical efficiency third gear (h_t) of 85%, coefficient of air resistance (C_d) of 0.3, rolling resistance coefficient (f_r) of 0.018, and final drive ratio (i_f) of 4.13. The engine develops (P_e) 65 kW, when the car is traveling at a speed (v) of 72 km/h on the third gear. Find:

a) The gearbox reduction ratio at the 3^rd gear (i_g3)

b) The air resistance (AR), taking the air density (ρ) as 1.21 kg/m³ when:

          i) The air velocity (v_air) is 0

          ii) The air velocity (v_air) is 15 km/h in opposite direction of the car

c) The car rolling resistance (RR)

d) The car tractive effort (TE)

e) The maximum car acceleration (a) (at air velocity = 0) at:

          i) A level road (0%)

          ii) Going up a gradient of 6%

f) The car velocity (v) at the same engine speed at direct drive.