Question 1

What is another way of saying engine braking?

Accepted Answer

Engine braking, also known as engine retarding, refers to the process of slowing a vehicle by releasing the accelerator and allowing the engine's internal components to slow the vehicle down.

Question 2

Which of the following best describes the role of engine braking in a truck braking system?

Accepted Answer

Engine braking is used to complement the service braking system by providing additional braking power through the engine, reducing the reliance on traditional brakes and helping to prevent brake fade during prolonged use.

Question 3

Which of the following describes a brake in which the retarding force is the upstroke of the engine piston on its compression stroke?

Accepted Answer

The correct term for a brake that utilizes the upstroke of the engine piston on its compression stroke to create a retarding force is an internal compression brake. This type of brake increases the engine's compression resistance, slowing down the vehicle without using the external braking system.

Question 4

When an internal engine compression brake is actuated, what role does the engine play?

Accepted Answer

When an internal engine compression brake is actuated, the engine essentially acts as an energy absorbing compressor. This is because it uses the engine's own compression mechanism to slow down the vehicle, absorbing the vehicle's kinetic energy in the process.

Question 5

When is the braking efficiency of any engine brake usually at its highest?

Accepted Answer

The answer of When is the braking efficiency of any...

Question 6

Which of the following types of engine brake uses hydraulic retarding?

Accepted Answer

Caterpillar BrakeSaver uses hydraulic retarding, which involves using the engine's oil pressure to slow down the vehicle. This method is different from the compression release engine brake (like Jacobs) or exhaust brakes (like PacBrake), as it directly uses hydraulic pressure for braking.

Question 7

When a Jacobs internal engine compression brake is actuated, at what point is cylinder compression dumped into the exhaust circuit?

Accepted Answer

The Jacobs internal engine compression brake, commonly known as a Jake Brake, dumps cylinder compression into the exhaust circuit around Top Dead Center (TDC) on the compression stroke. This action effectively converts the engine's power-producing expansions into a power-absorbing air compressor, slowing the vehicle.

Question 8

When an engine brake is actuated as part of cruise control management, what is the term sometimes used to describe the cruise control system?

Accepted Answer

Smart cruise control systems can adjust speed automatically, including using engine braking to slow down, hence the term "smart" is often used.

Question 9

When a Williams type exhaust brake is fully actuated, which of the following is true of the exhaust flow area through the brake?

Accepted Answer

The answer of When a Williams type exhaust brake is...

Question 10

What force is used to open the exhaust valves on a typical internal engine compression brake?

Accepted Answer

Internal engine compression brakes typically use a hydromechanical force to open the exhaust valves. This system uses hydraulic pressure in combination with mechanical linkages to control the opening of the valves, allowing the engine to slow the vehicle by releasing compressed air directly into the exhaust system, rather than converting the compression into power to drive the vehicle.

Question 11

Which of the following can be used by the driver to control the cycling of a typical internal engine compression brake?

Accepted Answer

The answer of Which of the following can be used...

Question 12

In a typical electronically controlled diesel engine, what force is used to time the hydraulic opening of the exhaust valves in an internal compression type brake?

Accepted Answer

Valve train movement is used to time the hydraulic opening of the exhaust valves in an internal compression type brake, as it directly influences the operation of the valves in coordination with the engine's cycle.

Question 13

For a truck driver to actuate an electromechanically-managed internal engine compression brake, all of the following switches would have to be closed EXCEPT:

Accepted Answer

The service brake application pressure switch is not required to be closed for the actuation of an electromechanically-managed internal engine compression brake. This system is typically engaged through the driver dash control switch, when the clutch is engaged (to ensure the vehicle is in gear), and when the accelerator or fuel control is not being applied, indicating the driver's intention to slow down without using the service brakes.

Question 14

When an engine brake is actuated on a current truck diesel engine, what is the maximum fueling permitted?

Accepted Answer

When an engine brake is actuated, the fueling is cut off to the engine, meaning no fuel is permitted. This helps in creating a braking effect by using the engine's compression resistance.

Question 15

When 100% engine braking is required of a Cummins Intebrake on a pre-2010 ISX engine, how many solenoids must be energized?

Accepted Answer

The Cummins Intebrake on a pre-2010 ISX engine requires three solenoids to be energized to achieve 100% engine braking.

Question 16

Technician A says that an advantage of Cummins Intebrake on a pre-2010 ISX engine is progressive retarding that options engine braking from one through all six engine cylinders. Technician B says that on this engine, Intebrake manages braking using both of its overhead camshafts. Who is right?

Accepted Answer

The answer of Technician A says that an advantage of...

Question 17

Which of the following is NOT an advantage of a Mercedes-Benz constant throttle valve (CTV) type engine brake?

Accepted Answer

The answer of Which of the following is NOT an...

Question 18

From where does cylinder gas blowdown occur during a CVT braking cycle?

Accepted Answer

The answer of From where does cylinder gas blowdown occur...

Question 19

Technician A says that most current engine brakes use the engine ECM to manage braking cycles. Technician B says that modern engine brakes can perform the majority of the braking requirements of a transport truck. Who is right?

Accepted Answer

The answer of Technician A says that most current engine...

Question 20

What additional feature does a Volvo EPG offer besides engine braking?

Accepted Answer

The answer of What additional feature does a Volvo EPG...

Quiz 13: Engine Retarders