Exam 33: Emission Control Systems

The technical term for the soot or the black smoke emitted from a diesel's exhaust pipe is _________________.

A catalytic converter is one of the most effective emission control devices on a vehicle for reducing HC, CO, and NO _X emissions.

Describe the operation of a digital EGR valve.

What is the vehicle emission control information (VECI)decal and where is it found?

Describe the purpose of the EVAP system.

Lower compression ratios reduce NO _X emissions.

Describe the purpose of the EGR system.

What gas has a rotten egg smell and is caused by sulfur in gasoline chemically reacting with air inside the catalytic converter?

What is the best way to check whether a catalytic converter is working?

What is the function of glow plugs?

Three types of emissions being controlled in gasoline engines are ____________________, ____________________, and ____________________.

The EVAP systems use a ____________________ canister to collect fuel vapors until they can be purged.

Technician A says the OBD-II EVAP system leak test monitor will not run if the fuel level is too high. Technician B says the monitor will not run if the fuel level is too low. Who is correct?

NO _X emissions are caused by nitrogen and oxygen uniting at cylinder temperatures above ______.

Blowby gases condense in the crankcase and react with the oil to form ______.

Technician A says the EVAP monitor for an OBD-II system determines whether there is sufficient purge flow by varying the purge solenoid duty cycle while monitoring change in STFT. Technician B says the canister vent solenoid must be open during the EVAP pressure test portion of the monitor. Who is correct?

Diesel engines emit less HC, CO, and CO₂ than spark ignition gasoline engines.

While discussing EGR systems with a differential pressure feedback EGR (DPFE)sensor, Technician A says the DPFE sensor sends a signal to the PCM in relation to intake manifold pressure. Technician B says the PCM can make corrections to the EGR flow if the actual flow does not match the desired flow. Who is correct?

Technician A says the air control valve (or air-switching valve)is a vacuum-operated valve that routes the air from the pump either to the exhaust manifold or to the catalytic converter. Technician B says the air bypass (AIRB)valve (or diverter (AIRD)valve)located between the air pump and the air control valve diverts the air pump output to the atmosphere or air filter during deceleration. Who is correct?

A digital EGR valve has up to _____ solenoids.