Exam 33: Emission Control Systems

Detonation sensors are being discussed. Technician A says most detonation sensors produce an analog signal. Technician B says the detonation sensor may be mounted in the exhaust. Who is correct?

Technician A says the production of CO₂ is directly related to the amount of fuel consumed; therefore, more fuel-efficient engines produce less CO₂. Technician B says imposing new CAFE [fuel economy] standards will, in effect, reduce CO₂ emissions. Who is correct?

A digital EGR valve has up to _____ solenoids.

The normal operating temperature for most catalytic converters is about ______.

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?

Heated air inlet systems, manifold heat control valves [heat risers], and EFE heater grids were used on older cars with carburetors and TBI fuel injection to prevent vaporized fuel from condensing inside the ____________________.

NO_X emissions are caused by nitrogen and oxygen uniting at cylinder temperatures above ______.

Excessive oxygen in the exhaust indicates an improper air/fuel mixture.

Technician A says the EGR vent solenoid is normally open. Technician B says the EGR control solenoid is normally open. Who is correct?

OBD-II systems monitor the EVAP system for leaks.

Carbon monoxide is being discussed. Technician A says as the air/fuel ratio becomes richer, the CO levels decrease. Technician B says CO is a colorless, odorless, and highly poisonous gas that can cause death. Who is correct?

A ____________________type EGR valve has three electric solenoids. Each of the solenoids and orifices has a different size. The rate of flow is based on the combination of solenoids turned on by the PCM.

An ignition misfire can cause excessive carbon monoxide emissions in the exhaust.

What is the function of glow plugs?

Under what conditions is the EGR valve open?

Describe the purpose of the EVAP system.

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

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

A three-way catalytic converter [TWC] stores oxygen when the air/fuel ratio is rich.

The ____________________ system removes blowby gases from the crankcase and recirculates them to the engine intake.