AUTOMOBILE ENGINEERING MCQ SECTION 5

41.When shear force at a point is zero, then bending moment is __________ at that point.

(A) zero

(B) minimum

(C) maximum

(D) infinity

Answer: - maximum

42. The point of contraflexure occurs in

(A) cantilever beams

(B) simply supported beams

(C) overhanging beam
(D) fixed beams

Answer: - overhanging beams

43. If the intake air temperature of I.C. engine increases, its efficiency will

(A) increase

(B) decrease

(C) remain same

(D) unpredictable

Answer: - Decrease

44. In a typical medium speed 4-stroke cycle diesel engine the inlet valve

(A) opens at 20° before top dead center and closes at 35° after the bottom dead center

(B) opens at top dead center and closes at bottom dead center

(C) opens at 10° after top dead center and closes 20° before the bottom dead center

(D) may open or close anywhere

Answer: - opens at 20° before top dead center and closes at 35° after the bottom dead center

45. The pressure and temperature at the end of compression stroke in a petrol engine are of the order of

(A) 4 – 6 kg/cm2 and 200 – 250°C

(B) 6 – 12 kg/cm2 and 250 – 350°C

(C) 12 – 20 kg/cm2 and 350 – 450°C

(D) 20 – 30 kg/cm2 and 450 – 500°C

Answer: - 6 – 12 kg/cm² and 250 – 350°C

46. The maximum temperature in the I.C. engine cylinder is of the order of

(A) 500 – 1000°C

(B) 1000 – 1500°C

(C) 1500 – 2000°C

(D) 2000 – 2500°C

Answer: - 2000 – 2500°C

47. The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will

(A) increase

(B) decrease

(C) be independent

(D) may increase or decrease depending on other factors

Answer: - Decrease

48. Combustion in compression ignition engines is

(A) homogeneous

(B) heterogeneous

(C) both (A) and (B)

(D) laminar

Answer: - Heterogeneous

49. The inlet valve of a four-stroke cycle I.C. engine remains open for nearly

(A) 180°

(B) 125°

(C) 235°

(D) 200°

Answer: - 235°

50. Which of the following is not an internal combustion engine?

(A) 2-stroke petrol engine

(B) 4-stroke petrol engine

(C) diesel engine

(D) steam turbine

Answer: - steam turbine