Exhaust Exhaust Emissions & Catalytic Converters 2 — Questions and Answers
Question 1: What does CARB stand for in the context of US vehicle emissions regulations?
- Carbon Reduction Bureau
- California Air Resources Board (Correct answer)
- Clean Air Regulatory Board
- Combustion and Reduction Bureau
Correct answer: California Air Resources Board
CARB is the California Air Resources Board, responsible for setting some of the strictest vehicle emissions standards in the United States.
Question 2: Which of the following is a common symptom of a clogged catalytic converter?
- Improved fuel economy
- Engine surging under load
- Rattling noise from the exhaust (Correct answer)
- Blue smoke from the exhaust
Correct answer: Rattling noise from the exhaust
A clogged catalytic converter restricts exhaust flow, causing back pressure that can result in a rattling noise, especially at startup or low speeds.
Question 3: What is the 'light-off temperature' of a catalytic converter?
- The temperature at which the exhaust manifold glows red
- The minimum temperature for the catalyst to become active (Correct answer)
- The temperature at which the converter melts
- The exhaust gas temperature at highway speeds
Correct answer: The minimum temperature for the catalyst to become active
The light-off temperature is the minimum temperature (typically around 400–600°F / 200–315°C) at which the catalytic converter begins to effectively reduce emissions.
Question 4: Which fuel additive can permanently damage a catalytic converter?
- Fuel injector cleaner
- Octane booster
- Leaded gasoline (Correct answer)
- Ethanol blend
Correct answer: Leaded gasoline
Lead poisons the precious metal catalysts inside a converter, permanently destroying its ability to oxidize and reduce exhaust pollutants.
Question 5: What type of catalytic converter is commonly used in diesel vehicles to reduce particulate matter?
- Three-way catalyst
- Diesel Oxidation Catalyst only
- Diesel Particulate Filter (DPF) (Correct answer)
- Selective Catalytic Reduction (SCR) only
Correct answer: Diesel Particulate Filter (DPF)
A Diesel Particulate Filter (DPF) physically traps soot particles from diesel exhaust, which are periodically burned off during a regeneration cycle.
Question 6: Which state in the US was the first to establish its own vehicle emissions testing standards stricter than the federal baseline?
- New York
- Texas
- California (Correct answer)
- Washington
Correct answer: California
California has been granted a federal waiver allowing it to set stricter emissions standards than the EPA baseline, which other states can choose to adopt.
Exhaust Exhaust Emissions & Catalytic Converters 2
What does CARB stand for in the context of US vehicle emissions regulations?