Week 6 - Computer Control Operations

Question 1

What is the tool of choice to accurately check the inlet restriction of a dry air filter?

Answer 1

water-filled manometer

Question 2

What is a typical maximum specified inlet restriction for an air filter on a turbocharged diesel?

Answer 2

25 inches H2O restriction

Question 3

Which of the following types of air filters has the highest filtering efficiencies?
a. Centrifugal precleaners b. Dry, positive c. Dry, non-positive d. Oil bath

Answer 3

Dry, positive

Question 4

Which of the following should be performed first when checking an engine that produces black smoke under load?
a. Injection timing b. Air filter restriction test c. Plugged DPF d. Fuel quality by chemical lab analysis

Answer 4

Air filter restriction test

Question 5

Which of the following best describes the intended function of a C-EGR system on a diesel engine?
a. It assists the turbocharger in boosting intake pressure b. It increases engine breathing efficiency c. It dilutes the intake charge with cooled dead gas d,. It preheats the intake charge to the cylinder

Answer 5

It dilutes the intake charge with cooled dead gas

Question 6

What best describes the function of a wastegate in a current turbo-boosted diesel engine?

Answer 6

Allows exhaust gas to bypass the turbine

Question 7

When series turbocharging is used on a current diesel engine, which of the following should be true?
a. Twin turbos are arranged in parallel b. Intake air must pass through the turbine housing of both turbos c. Exhaust gas must pass through the turbine housing of both turbos c. The VG actuator is in series with the EGR mixer

Answer 7

Exhaust gas must pass through the turbine housing of both turbos

Question 8

What is the critical flow area managed by a VG turbo using a variable nozzle operating principle?

Answer 8

Turbine volute

Question 9

To produce peak manifold boost from a VN-type turbocharge, which of the following should be true?
a. Wastegate is fully closed b. Wastgate is fully open c. Vanes are in the nearly closed position d. Vance are in the fully open position

Answer 9

Vanes are in the nearly closed position

Question 10

The constant geometry turbocharger used in a highway diesel engine with turbo corresponding is usually designed to produce optimum efficiency at which rpm?

Answer 10

Rated speed and load

Question 11

Technician A states that a dry air filter functions at optimum entrapment efficiency when it is new and that by the time it requires replacing, it has lower filtering efficiencies. Technician B states that oil bath filters are seldom used with today’s highway diesel engines because they have low filtering efficiencies. Who is correct?
a. Technician A b. Technician B c. Both A and B d. Neither A nor B

Answer 11

Technician B only

Question 12

Technician A states that turbo-compounded diesel engines such as the DDC DD15 use CG turbos to supply boost air to the intake manifold. Technician B states that turbo compounding allos the turbo to directly contribute drive torque to the engine drivetrain by means of reduction gearing. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 12

Both A and B

Question 13

Technician A states that the term “manifold boost” is used to describe breathing on a turbocharged engine. Technician B states that turbine speeds on truck diesel engines can exceed 100,000 rpm. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 13

Both A and B

Question 14

Technician A states that using a light bulb inside an air filter element is a reliable means of determining whether the filter is plugged. Technician B states that air filters are vest left untouched between service intervals unless the filter restriction gauge indicated an out-of-specification reading. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 14

Technician B only

Question 15

Technician A states that the first item to be checked when an engine produces black smoke should be the air filter inlet restriction gauge. Technician B states that whenever an engine produces black smoke, the air filter should automatically be changed. Who is correct?

Answer 15

Technician A only

Question 16

Which of the following methods would identify the location of a hole or tear in an air filter element?
a. Air inlet restriction gauge b. Lightbulb test c. Regulated air pressure test d. Manometer test

Answer 16

Lightbulb test

Question 17

When is a diesel engine turbocharger capable of highest rotational speeds?

Answer 17

When rejected heat is greatest

Question 18

Which of the following components would be located in a diesel exhaust gas aftertreatment canister?
a. SCR b. DPF c. Oxidation converter d. Any or all of the above

Answer 18

Any or all of the above

Question 19

Which of the following best describes the function of a VG turbocharger?
a. It reroutes NOx back into the engine cylinders b. It reroutes EGR gas into the DPF c. It behaves like a large turbocharger when engine load is high d. It behaves like a small turbocharger when engine load is high

Answer 19

It behaves like a large turbocharger when engine load is high

Question 20

Technician A states that the function of a turbocharger wastegate is a divert exhaust gas around the turbine directly into the exhaust system. Technician B states that a wastgated turbocharger can improve turbine efficiencies at lower loads and rpms. who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 20

Both A and B