190202a Air Induction and Exhaust Systems Flashcards
Identify 4 functions of an air induction system
Cleaning the air supply, silencing the intake flow, providing air for combustion purposes, cooling the intake airflow, providing extra air for supercharged engines
Identify the two main air induction systems
Naturally aspirated and supercharged/turbocharged engines
What is the approximate volumetric efficiency of a naturally aspirated engine
80%
Which component is not considered part of the air cleaner assembly. Filter element, air inlet restriction gauge, intake manifold, air filter housing assembly
Intake manifold
Explain the purpose of a pre-cleaner
To remove large dirt and dust particles from the incoming airstream. This action reduces the filter load on main air filter element and creates longer filter service life
What are the two benefits of using an automatic dust ejection system
Reduces vehicle downtime and reduces service labor cost as the system is automatic
What are three disadvantages of using an oil bath type of air cleaner assembly
On rough terrain oil could move into the intake manifold and overspeed engine, cold-weather thickens the oil as well and affects its ability to clean incoming air, low airflow speed means less oil is picked up and fewer dust particles are trapped
Why are small dry air filter elements able to function so efficiently
It’s composed of pleated paper providing a large surface area
What’s the purpose of the inner air filter element as used in a two stage filter system
The inner is a safety should the primary filter develop a crack or pinhole leak
What’s the purpose of an inlet restriction gauge
It assists the operator or serviceman with an indication of how plugged the air filter is
What is a constant tension or Constant torque hose clamp
A hose clamp that uses a spring device to maintain an even clamping tension as a hose deforms because of temperature or pressure changes
What’s the primary function of an exhaust system
It’s used primarily to gather exhaust gases from the cylinders, direct them to a silencing system and then disperse them into the atmosphere
What’s the purpose of an air inlet shutdown device
Generally protect the engine from over speeding due to a fuel supply from an external source. This is especially possible in oil field operation
When would you use multipiece exhaust manifolds
When engine access is limited or multiple cylinder heads are used
What is flex piping often used for an exhaust systems
To allow movement between two fixed sections of piping, or between a pipe and a major exhaust component like a muffler
True or false mufflers can either be a straight through or reverse flow design
True
Fiberglass packing is used in some mufflers to absorb sound waves. True or false
True
What are three reasons you have a heatshield on an exhaust system
Protect grass and brush from the hot muffler, prevent operator or worker injury through contact, protect the cab or sleeper from the heat of the muffler or exhaust stack
What’s the main reason you inspect the air induction system for signs of leakage
To prevent unfiltered air from entering the engine at any point in the system
True or false. Internal engine damage, caused by contaminated inlet air, may be reduced by approximately 80%, when effective pre-cleaners are used
true
True or false. The air filter service interval is highly dependent on the vehicles operating conditions and the indications provided by any restriction gauge
True
Soot trails on an exhaust pipe, or near an exhaust joint, may indicate an exhaust leak
True or false
True
True or false. And engine will operate at its maximum efficiency if enough air reaches the combustion chambers. It is less important if the exhaust system is blocked since the exhaust gases leave the engine under pressure
False. Intake and exhaust systems must be free-flowing
What is one of the reasons an engine would have black exhaust
Shortage of air during the combustion process, or over fueling in a performance diesel like the drag trucks
What does blue smoke from the exhaust indicate
The engine is burning oil
What type of manometer is used when testing the air induction system for air restrictions. Explain why
You must use a water manometer because mercury manometer’s could create a health hazard if any mercury was drawn into the engine
What type of manometer is a suitable tool to test an exhaust system for excessive back pressure
Mercury manometer or a pressure gauge is used to check the exhaust back pressure
What problems could arise if an intake hose was to leak
dust entering the engine
loss of intake air to atmosphere
What two problems could an air to air intercooler have? With an air leaking problem.
air could be lost to atmosphere or damage may allow dust to enter the engine
Define Venturi
specially shaped tube that has a restriction and creates pressure drop when exhaust gas passes through the restriction
