Deck 43: Emission Control System Fundamentals, Gasoline and Diesel

Question 1

Three-way catalytic converters use ____, or sometimes palladium, as a catalyst for their reduction portion (the part that controls NO_X).

A)silicon
B)lead
C)rhodium
D)tungsten

Answer 1

C

Question 2

____________________ is produced when hydrocarbons and oxides of nitrogen react with sunlight to form a dirty yellow-brown haze in the air.

Answer 2

Photochemical smog
Smog

Question 3

Positive crankcase ventilation systems today are open PCV systems.

Answer 3

False

Question 4

All of the following statements are true EXCEPT:

A)emission of fuel vapors from the fuel tank can be controlled by sealing the fuel system from the atmosphere.
B)on a hot day, gasoline in the tank contracts.
C)air must be allowed to enter the fuel tank to take the place of fuel as it is consumed.
D)the fuel tank can be vented by the gas cap or by a vent solenoid.

Question 5

Aluminum is an oxide of alumina that is very porous.

Question 6

To regulate EGR more accurately, some EGR systems use ____________________, in the same way as fuel injection systems, to rapidly cycle an EGR vacuum control solenoid on and off.

Question 7

All of the following statements about the air injection system are true EXCEPT:

A)a diverter valve, or a similar type of device, prevents a backfire during deceleration.
B)a one-way check valve prevents exhaust from backing up into the hoses and pump.
C)a high-pressure vane-type pump driven by a crankshaft belt provides air.
D)computer-controlled three-way catalyst systems include an air switching valve that moves the injected air into the exhaust manifold or into part of the catalytic converter.

Question 8

The heart of the evaporative emission system is a(n) ____________________ canister.

Question 9

CO₂ is a greenhouse gas that traps heat in the atmosphere.

Question 10

While having a discussion, Technician A says that preventing the injection of air into the reduction (NO_X) chamber of the cat helps reduce NO_X. Technician B says that this has no effect of NO_X. Who is correct?

A)A only
B)B only
C)Both A and B
D)Neither A nor B

Question 11

An oxidizing catalyst starts to work at temperatures between ____.

A)100^° and 200°F
B)200^° and 300^°F
C)300^° and 400^°F
D)500^° and 600^°F

Question 12

The part that is MOST-Likely mounted closer to the engine than the muffler so it can be quickly heated by exhaust is:

A)intercooler
B)catalytic converter
C)plenum
D)resonator

Question 13

____________________ are airborne microscopic particles like dust and soot that are especially prevalent in diesel engine exhaust.

Question 14

Which of the following is LEAST-Likely a source of emissions?

A)Crankcase
B)Evaporation
C)Exhaust
D)Plenum

Question 15

Carbon monoxide (CO₂) emissions result when gasoline is not completely burned.

Question 16

The system that is MOST-Likely used to prevent the emission of hydrocarbons in blowby gases from the crankcase by scavenging them from the crankcase and reintroducing them into the combustion chambers is:

A)PCV system
B)PVC system
C)EGR system
D)CVS system

Question 17

While having a discussion, Technician A says that as the temperature of the engine and air under the hood increases, the evaporation rate of the fuel increases. Technician B says that with the engine running, fresh fuel is always coming into the float bowl. Who is correct?

A)A only
B)B only
C)Both A and B
D)Neither A nor B

Question 18

Which of the following statements is LEAST-Likely true?

A)A liquid vapor separator is part of the fuel tank or the expansion tank.
B)The rollover valve has a ball or plunger that blocks the line when the vehicle is started.
C)A vapor canister is only allowed to purge itself of vapor storage when the engine is running.
D)Some cars have a rollover valve in the vent line from the fuel tank.

Question 19

Exhaust backpressure is a good indicator of engine load.

Question 20

A(n) ____________________ is a substance that causes a chemical reaction to occur without undergoing any change to itself.

Question 21

Provide a brief description of each of the three types of catalytic converters.

Question 22

What are the advantages of a PCV system?

Question 23

What is the advantage of a PCV valve over a road draft tube?

Question 24

Discuss three sources of hydrocarbons (HC).

Question 25

Manufacturers use engine, ignition, and fuel modifications to achieve federally mandated standards. Briefly discuss two common modifications.