Air Pollution And Its Control In Automobile — Part 1 MCQs with Explanations

Knocking is an undesirable phenomenon in petrol engines. It happens when the air-fuel mixture in the cylinder ignites prematurely and uncontrollably. This creates pressure waves that can damage the engine and reduce its efficiency. Lead compounds , like tetraethyl lead (TEL), were historically added to petrol to increase the octane rating . A higher octane rating makes petrol more resistant to knocking . Therefore, the primary reason for adding lead compounds was to reduce or prevent knocking . The other options are incorrect because: Option B: While some additives *might* have a minor effect on HC emissions, it wasn't the main reason for using lead. Option C: Lead compounds don't directly reduce exhaust temperature. Option D: Lead compounds primarily improved engine efficiency by preventing knocking, but didn't directly "increase power output" as their main function.

An EGR (Exhaust Gas Recirculation) lift sensor is used to sense the extent to which the EGR valve is open . EGR is a technique used in automotive engines to reduce nitrogen oxide (NOx) emissions by recirculating a portion of the exhaust gases into the intake air. The EGR valve controls the flow of these exhaust gases. The EGR lift sensor is responsible for monitoring the position of the EGR valve. It detects how much the EGR valve is open or closed, allowing the engine control unit (ECU) to adjust the EGR flow accordingly. This sensor helps optimize the EGR system's operation to meet emissions regulations and improve engine efficiency. The other options are not typically sensed by an EGR lift sensor: Option A: The oxygen content of the exhaust gas is usually monitored by an oxygen sensor (O2 sensor). Option B: The exhaust gas temperature is monitored by an exhaust gas temperature sensor. Option D: The exhaust gas flow rate is not directly sensed by an EGR lift sensor. So, the correct answer is Option C: The extent to which the EGR valve is open , which is the primary variable sensed by an EGR lift sensor in an EGR system.

To prevent pressure build up is the correct answer to “What is the purpose of crank case ventilation”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Exhaust system and intake system is the correct answer to “Where EGR valve connected”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

35% is the correct answer to “A . . . . . . . . reduction of cold-start HC has been achieved.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Intake ports is the correct answer to “In a petrol fuel injected engine, the air and fuel are mixed in the”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

All of these is the correct answer to “Reduction of formation of pollutants is achieved by:”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Automotive Research Association of India (ARAI) is the correct answer to “Pune-based organisation . . . . . . . . conducted a study using a 15% M - 15 methanol blend in vehicles and tested them for 3,000 km to evaluate emissions in real-world conditions as well as to check the performance of the vehicles.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

4.5% is the correct answer to “Idling co-emission for all two and three wheeled petrol vehicles should not exceed . . . . . . . . by volume.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

True is the correct answer to “More than 90 to 95% of carbon particles originally generated within an engine are thus converted to CO”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

False is the correct answer to “The exhaust of CI engines does not contain solid carbon soot particles that are generated in the fuel-rich zones within the cylinder during combustion.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Compressed ignition engine is the correct answer to “Which engine emits more amounts of nitrogen oxides (NO x )”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Maximum is the correct answer to “EGR combines with the exhaust residual left in the cylinder from the previous cycle to effectively reduce the . . . . . . . . . combustion temperature.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

True is the correct answer to “When scavenging is done, some of the air and fuel mix with the exhaust gases and are expelled out of the cylinder before the exhaust port closes.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Distributes intake air equally to the cylinders is the correct answer to “The main function of the intake manifold is that it”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

To reduce peak combustion temperature and lower the formation of NO is the correct answer to “EGR system recirculates a smallmetered amount of the inert exhaust gas back into the intake manifold:”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

5000 is the correct answer to “A single soot particle may contain up to . . . . . . . . carbon spheres.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Fuel tank is the correct answer to “The liquid-vapour separator is located in the”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

To control smoke is the correct answer to “Why is the fumigation technique used”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Combo of EGR and SCR is the correct answer to “How do we achieve near zero emission diesel engines”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Exhaust gas recirculation is the correct answer to “Name the emission control technique when some amount of gases feed into the intake manifold of a running engine”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Idling is the correct answer to “During which condition of the vehicle does NO x emission in SI engine will be lowest”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Air cleaner - carburettor (or throttle body) - intake manifold - intake ports - cylinders is the correct answer to “The path taken by the intake air is”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

The combustion temperature decreased is the correct answer to “When water emulsion is used as the fuel in SI engine the emission of nitrogen oxides reduces significantly, this is due to”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Is returned to the fuel tank is the correct answer to “When a fuel tank becomes cold such that a vacuum is created inside it then the fuel vapour held in the EVAP control canister”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Combustion within a narrow margin of the stoichiometric air-fuel ratio is the correct answer to “The condition that is required for simultaneous treatment of CO, HC and NOx in a three way catalytic is”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Nox is the correct answer to “Which of the following exhaust gas component is reduced significantly by retardation of the ignition timing”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Reduce NOx is the correct answer to “What is the purpose of selective catalytic reduction (SCR)”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Air flows through the canister on its way to the intake manifold is the correct answer to “Purging of the charcoal canister occurs when”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Low-cost is the correct answer to “Cyanuric acid is a . . . . . . . . solid material that sublimes in the exhaust flow.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

All of the above is the correct answer to “Which of the following are the separable methods used in exhaust gas measurement”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Excessive oil with fuel is the correct answer to “Engine emits white smoke due to”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

NOx is the correct answer to “Which of the following cannot be reduced by thermal converters”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

True is the correct answer to “Ozone is harmful to plants and trees and causes very heavy crop losses each year.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

False is the correct answer to “Diatomic oxygen is highly reactive and initiates a number of different reactions.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

1 and 2 only is the correct answer to “In Diesel engines, the control of black smoke in the exhaust can be achieved by: 1. Running the engine at lower load. 2. Maintaining the injection system perfect. 3. Using Diesel fuel of higher Cetane number. Which of the above statements are correct”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

To recirculate a portion of exhaust gas is the correct answer to “The correct function of EGR system is”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

HC is the correct answer to “. . . . . . . . is collected during engine startup time when the catalytic converter is cold, and then later released back into the exhaust flow when the converter is hot.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

NOx is the correct answer to “Which one of the following toxic components of exhaust gas is stripped of oxygen in three-way catalytic converter”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.

Turns the turbine wheel is the correct answer to “In a turbocharger, the exhaust gases from the cylinder.”. This question is standard in competitive examination syllabi for Air Pollution And Its Control In Automobile.