Ch 13 – Engine Retarders

1. which type of engine brake uses the compression stroke of the piston as its retarding stroke?

INTERNAL COMPRESSION BRAKE

2. which type of engine brake uses the exhaust stroke of the piston as its retarding stroke?

EXTERNAL COMPRESSION BRAKE

3. Technician “A” states that the cummins isx interbrake is capable of optioning engine braking on just one engine cyinder. Technician “B” states that the cummins ISX interbrake is an external engine compression brake. Who is correct?

Both

4. The effective braking cycle on most internal engine compression brakes fitted to hydromechanical engines is actuated by using which of the following?

ELECTRIC OVER HYDRAULIC

5. When will any kind of engine brake usually operate at peak efficiency?

AT THE HIGHEST RPM

6. Technician “A” states that on most internal engine compression brakes, the effective braking stroke of the piston is the compression stroke. Technician B states that on some engine brake systems, both the compression and exhaust strokes can deliver retarding force. Who is correct?

Both A & B

7. The operating principle of an internal engine compession brake is to convert the engine into an:

ENERGY ABSORBING COMPRESSOR

8. The energy of the vehicle motion is to what energy form when an engine compression brake is used?

HEAT ENERGY

9. Technician A states that the force used to actuate the hydraulic circuit in a typical Jacobs brake is delivered by an electrically actuated solenoid. Technician “B” states that Jacobs brake solenoids act as a pilot switch to control oil flow to the hydraulic actuation circuit. Who is correct?

Tech B only

10. When an internal engine compression brake is actuated, where does gas blowdown occur?

CLOSE TO “TDC” AT THE COMPLETION OF THE COMPRESSION STOKE

11. Which of the following engine brakes offers progressive step braking using from one to all six cylinders

A. Cummins Intebrake on pre 2010 ISX

12. Which vehicle technology enables nonengine controllers to request engine braking cycles?

B. Multiplexing

13. Technician A says that it is permissible to reuse and exhaust manifold gasket if it less than 1 year old and not cracked with a light coat of grease. Technician B says it may be necessary to re-torque exhaust manifold bolts after initial warm-up and cool-down. Who is right?

A only

14. Which of the following is contained in diesel engines exhaust?

oxides of nitrogen
hydrocarbons
particulate matter (soot)

15. Technician A says that the job of the waste gate or turbine bypass valve is to provide a method of limiting turbocharger speed. Technician B says that the waste gate and turbine bypass valve actually divert exhaust gas to warm intake air during cold operating conditions. Who is right?

Both A and B

16. Diesel Particulate Filters can regenerate by increasing the exhaust temperature to:

1200º plus

17. Particulate matter consists of solid particles of carbon, unburned hydrocarbons and dirt from sandy roads.

False

18. Technician A says that the exhaust ports in the engine and the passages in the exhaust manifold are large to allow free flow and expansion of the escaping gases. Technician B says that ports and passage are rather narrow to promote the fast movement of exhaust gas needed to turn the turbocharger turbine. Who is right?

Tech A

19. Pyrometers can be used to test the psi in the exhaust pipe or turbocharger

False

20.

It has been estimated that each 2 psi of back pressure causes a loss of about _____ engine horsepower.

4

21. Technician A says that oil leaking out of the exhaust ports can indicate the engine intake valve guides are leaking and worn. Technician B says that a plug air cleaner and prolong engine idle time can also be the cause. Who is right?

Both

22. Aftercoolers provide all of the following, EXCEPT:

it makes the engine run slower than intercoolers