Question 1

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

Accepted Answer

There are three types of catalytic converters:
1. The earliest catalytic converter, called a two-way converter, was designed to oxidize HC and CO, converting them into H₂O and CO₂.
2. The three-way single bed converter oxidizes HC and CO and also reduces harmful NO_X into harmless nitrogen and O₂. The NO_X portion of the converter is called a reduction catalyst. The O₂ produced in the NO_X portion of the converter aids in oxidizing HC and CO.
3. The three-way dual bed converter has two chambers. A tube between the two chambers provides O₂ to the rear oxidation chamber, supplied from the air pump.

Question 2

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?

Accepted Answer

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

Question 3

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:

Accepted Answer

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

Question 4

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

Accepted Answer

Photochemi

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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. 
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 7

Aluminum is an oxide of alumina that is very porous.

Accepted Answer

A) True 
 B)False

Question 8

An oxidizing catalyst starts to work at temperatures between ____.

Accepted Answer

A)  1000 and 2000F 
B)  2000 and 3000F 
C)  3000 and 4000F 
D)  5000 and 6000F 
A)  1000 and 2000F 
B)  2000 and 3000F 
C)  3000 and 4000F 
D)  5000 and 6000F

Question 9

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

Accepted Answer

The answer of The heart of the evaporative emission system...

Question 10

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

Accepted Answer

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

Question 11

Exhaust backpressure is a good indicator of engine load.

Accepted Answer

A) True 
 B)False

Question 12

What are the advantages of a PCV system?

Accepted Answer

Besides eliminating one source of air po

Question 13

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.

Accepted Answer

pulse widt

Question 14

Positive crankcase ventilation systems today are open PCV systems.

Accepted Answer

A) True 
 B)False

Question 15

Discuss three sources of hydrocarbons (HC).

Accepted Answer

- Blowby gases are those that leak past

Question 16

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

Accepted Answer

The answer of ____________________ are airborne microscopic particles like dust...

Question 17

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

Accepted Answer

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

Question 18

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

Accepted Answer

- A cool area of fuel remains unburned a

Question 19

All of the following statements are true EXCEPT:

Accepted Answer

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. 
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 20

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

Accepted Answer

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

Exam 43: Emission Control System Fundamentals

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

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?

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:

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

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

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

Aluminum is an oxide of alumina that is very porous.

An oxidizing catalyst starts to work at temperatures between ____.

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

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

Exhaust backpressure is a good indicator of engine load.

What are the advantages of a PCV system?

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.

Positive crankcase ventilation systems today are open PCV systems.

Discuss three sources of hydrocarbons (HC).

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

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

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

All of the following statements are true EXCEPT:

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

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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?

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