Performance Testing of IC Engines: Supercharging

What is the purpose of supercharging an engine?

To decrease the air density entering the cylinders
To raise the density of the air charge before it enters the cylinders (correct)
To decrease the mass of air inducted into the cylinders
To increase the fuel consumption per brake kW hour

How does supercharging lead to higher engine power output?

By reducing the air-fuel mixture per cycle
By decreasing the oxygen available for combustion
By decreasing the air density before combustion
By providing more oxygen available for combustion than naturally aspirated engines (correct)

What is a key point to note about supercharging an engine?

Supercharging increases fuel consumption per brake kW hour
Supercharging decreases engine power output
Supercharging consumes a certain percentage of power for compressing air (correct)
Supercharging reduces air and fuel intake per cycle

How does supercharging impact the amount of air and fuel per cycle in an engine?

It increases the amount of air and fuel per cycle (C) Signup and view all the answers

What trend is emerging in engine design to meet emission legislation and consumer demands?

Adopting smaller displacement engines with supercharging (A) Signup and view all the answers

What is the main benefit of having forced induction, or supercharging, in engines?

Increased oxygen availability for combustion (D) Signup and view all the answers

Which type of supercharger is commonly used in automotive engines?

Centrifugal type (A) Signup and view all the answers

What is the approximate speed at which the impeller of a centrifugal type supercharger runs?

$80,000$ revolutions per minute (D) Signup and view all the answers

Which supercharger operates like a gear pump?

Root's type (D) Signup and view all the answers

What is a special problem associated with the vane type supercharger?

Wear of tips of the vanes over time (B) Signup and view all the answers

Which method of supercharging involves an independently driven compressor or blower?

Ram effect (A) Signup and view all the answers

What is a key consideration when choosing a supercharger for a specific application?

Longevity and wear characteristics (B) Signup and view all the answers

What is a crucial factor to prevent detonation when using supercharging?

Using a fuel with better antiknock characteristics (A) Signup and view all the answers

Which material is often used to make impellers for superchargers?

Aluminum (C) Signup and view all the answers

What is the significance of supplying more air-fuel mixture into the cylinder due to supercharging?

Improved engine performance (D) Signup and view all the answers

In which situation would a centrifugal type supercharger be most suitable?

Low-speed applications (A) Signup and view all the answers

What is the role of the waste gate in a turbocharger assembly?

Control the maximum boost pressure to prevent engine damage (C) Signup and view all the answers

Which component can help maintain higher power levels at higher altitudes in an engine?

Supercharger (B) Signup and view all the answers

How do superchargers contribute to improved fuel efficiency?

By enabling smaller engines to produce power comparable to larger ones (B) Signup and view all the answers

What is the main drawback of superchargers compared to turbochargers?

Higher maintenance requirements (B) Signup and view all the answers

What is the main aim of the designer in relation to power loss due to friction?

To minimize power loss in friction (D) Signup and view all the answers

Which method is also known as the fuel rate extrapolation method?

Willan's Line Method (D) Signup and view all the answers

Which type of engine operation shows an appreciable reduction in smoke for a turbocharged engine?

Overload operation (C) Signup and view all the answers

What is the measure of gross power developed by the engine in the Morse test?

Brake power (C) Signup and view all the answers

What is the primary function of a waste gate solenoid in a computer-controlled turbocharging system?

Open or close the waste gate to control boost pressure (C) Signup and view all the answers

Why is it essential to take great care when extrapolating the line in Willan's Line Method?

To ensure accuracy due to non-linear graph behavior (B) Signup and view all the answers

What is a significant advantage of superchargers over turbochargers in terms of power delivery?

Immediate power delivery (B) Signup and view all the answers

What does the Morse test assume about pumping and friction losses when a cylinder is made inoperative?

They remain constant (A) Signup and view all the answers

In Willan's Line Method, what does the negative intercept of the x-axis represent?

Energy spent in overcoming friction (C) Signup and view all the answers

Why is the Morse test applicable only to multi-cylinder engines?

It requires more than one cylinder for comparison purposes (A) Signup and view all the answers

What is considered a drawback of Willan's Line Method with regards to data extrapolation?

'The line' does not reflect engine efficiency changes accurately (C) Signup and view all the answers

'The directional margin of error' in Willan's Line Method refers to what?

The steepness of the slope on the graph (D) Signup and view all the answers

Why is it important to consider as many readings as possible at light loads in Willan's Line Method?

To establish the true nature of 'the curve' (C) Signup and view all the answers

What is the major advantage of supercharging mentioned in the text?

Quicker acceleration of vehicle (C) Signup and view all the answers

Why do supercharged engines usually have a greater valve overlap period?

To allow cooler air to flow past the valves and piston crown (C) Signup and view all the answers

Which part of a turbocharger is responsible for sucking air into the compressor housing?

Turbine wheel (D) Signup and view all the answers

What limits the degree of supercharging an engine can withstand according to the text?

Durability, reliability, and fuel economy (D) Signup and view all the answers

Why is greater valve overlap important in supercharged engines?

To allow greater time for cooler air to flow past valves and piston crown (D) Signup and view all the answers

What is the purpose of turbolag mentioned in the context of turbocharging?

To give a short delay before increasing manifold pressure (D) Signup and view all the answers

How do supercharged engines overcome the problem of increased heat generation?

By using materials that can withstand higher temperatures (D) Signup and view all the answers

What is one of the limitations of supercharging on engine parts according to the text?

Increased thermal load on engine parts (A) Signup and view all the answers