Automotive Engine Components Design Multiple Choice Questions on “IC Engine – Piston Materials”.
1. Which of the following material is not used in the manufacturing of pistons?
a) Steel
b) Aluminum alloy
c) Cast iron
d) Mild steel
Answer: d
Clarification: Steel, Aluminum alloy and Cast iron are the materials used in the pistons based on there thermal capacity, density factor, and lubrication property. Whereas mild steel is a ductile material and it is not used in pistons.
2. Which property of the aluminum alloy is preferred in pistons?
a) Color
b) Density factor
c) Thermal property
d) Aesthetics
Answer: b
Clarification: The Density factor of aluminum alloy is (frac{1}{3})rd to that of cast iron, this results in lightweight construction and reduces inertia force, make piston moment easier.
3. Which is the preferred process used in the manufacturing of pistons?
a) Forging
b) Casting
c) Forming
d) Machining
Answer: a
Clarification: Pistons manufactured using the Forging process because this process is more reliable and stronger than casting and can withstand high thermal stresses.
4. Earlier, which material was used in pistons?
a) Aluminum alloy
b) Cast iron
c) Steel
d) Brass
Answer: b
Clarification: Earlier, cast iron was widely used as it has higher strength compared to aluminum alloy. This helps to provide thin and small sections for the parts of cast iron piston.
5. Why aluminum alloy pistons are used in highly rated engine?
a) Due to its thermal factor
b) Due to its alloying element
c) Due to the piston speed
d) Due to circular
Answer: c
Clarification: Highly rated engines are mostly used in race cars and high-end cars; these cars require speed. Aluminum pistons can achieve piston speed above 6m/s. Hence, aluminum alloy pistons are used in a highly rated engine.
6. Cast iron pistons were used in low-speed cars, why?
a) Due to inertia force
b) Due to low-speed piston
c) Due to momentum
d) Due to centrifugal force
Answer: b
Clarification: Cast iron pistons were used in low-speed cars because its piston speed is always less than 6 m/s, this speed was due to the density of piston.
7. Why aluminum alloy pistons need more clearance?
a) Free moment
b) Good fixture
c) Thermal expansion
d) Cold start
Answer: c
Clarification: The coefficient of thermal expansion of the aluminum piston is approximately twice that of cast iron piston. Hence, Aluminum alloy pistons need more clearance.
8. Why cast iron was used in pistons earlier?
a) Availability
b) Cost
c) Luster property
d) Design feature
Answer: a
Clarification: Availability of cast iron was more when compared to steel, aluminum alloy, etc…, People found the manufacturing process using cast iron was easy until density came into the picture.