310S Fuel and Emission Systems

Question 1

What is the stoichiometric air-fuel ratio for gasoline engines?

Accepted Answer

14.7:1

Answer

12.5:1

Answer

16.2:1

Answer

10.0:1

Question 2

What does a wideband oxygen sensor measure that a narrowband sensor cannot?

Accepted Answer

The exact air-fuel ratio across a wide range rather than just rich or lean of stoichiometric

Answer

Exhaust gas temperature

Answer

The concentration of NOx in the exhaust

Answer

Catalytic converter internal temperature

Question 3

What is the function of the evaporative emission (EVAP) system?

Accepted Answer

To capture and store fuel vapours from the fuel tank and purge them into the engine for combustion

Answer

To recirculate exhaust gases back into the intake

Answer

To cool the fuel before it enters the injectors

Answer

To filter particulate matter from the exhaust

Question 4

What component controls the amount of fuel delivered by a port fuel injector?

Accepted Answer

The ECM controlling the injector pulse width (on-time)

Answer

The fuel pressure regulator only

Answer

The throttle position sensor directly

Answer

The fuel pump speed

Question 5

What does a catalytic converter do to reduce harmful emissions?

Accepted Answer

It uses precious metal catalysts to chemically convert CO, HC, and NOx into less harmful CO2, H2O, and N2

Answer

It filters particulate matter from the exhaust stream

Answer

It cools exhaust gases before they exit the tailpipe

Answer

It recirculates a portion of exhaust back into the intake

Question 6

What is the purpose of the exhaust gas recirculation (EGR) valve?

Accepted Answer

To reduce combustion temperatures and lower NOx emissions by introducing inert exhaust gas into the intake

Answer

To increase engine power at high RPM

Answer

To improve fuel economy at idle

Answer

To prevent exhaust leaks at the manifold