Chapter 72- Internal Combustion Engines Flashcards
In a compression engine the fuel is ignited by
The compressed air temperature
Diesel engine governing is accomplished by
Varying the fuel quantity
Internal combustion engines used to drive gas compression machinery and which burn natural gas operate on the _______ stroke cycle
Two or four
How is fuel in a gasoline engine delivered?
An injector
A carburetor
What is a fuels resistance to premature detonation called?
Octane rating
Four-stroke cycle valves are operated
Cams
The purpose of a spark plug
To ignite the air fuel mixture in a gasoline engine
An engine which develops one power stroke with every other turn of the crankshaft is the
Four stroke natural gas engine
Four cycle engine lubrication may be accomplished by
Pumping oil under pressure
An example of a gasoline engine which gives high torque at low speeds would be A. chainsaw B. two cycle snowmobile C. four stroke motor cross motorcycle D. two cycle lawnmower E. two cycle transit bus
C
A major difficulty encountered with a two-stroke cycle engine is
Exhausting the spent gasses from the cylinder
When does the exhaust valve open on a four cycle engine
The end of the power stroke
A four stroke ignition engine in theory has ______ the power of a two stroke engine
Half
When does the spark plug ignite the air/fuel mixture in a four stroke engine
Near the end of the compression stroke
How many ports does a simple two stroke spark ignition engine have?
2
Define cylinder scavenging
The removal of exhaust gasses from a cylinder
Compression engines
Will compress air only on the compression stroke
An injection nozzle is used to _________ the fuel in a Diesel engine
Atomize
In larger two stroke Diesel engines how is scavenging air provided
With superchargers
The injection pump of a Diesel engine is driven by the
Camshaft
Ignition in a Diesel engine is started by
Compression in the cylinder
What is a diesels engines camshaft driven by?
The crankshaft
How high might the compression ratio of a Diesel engine be
25:1
What is the purpose of a pushrods in a typical four stroke Diesel engine?
To operate a rocker arm
How might the frame of a Diesel engine be constructed?
Cast or welded
Using a compressed air starting motor is a popular method of starting a
Large stationary Diesel engine
When using compressed air to each cylinder for starting purposes, the pressure is approximately
2100 Kpa
Reduction in sealing qualities between the piston rings and cylinder wall by the lube oil may be a result of
High cooling water temperature
Large internal combustion engines achieve cooling by use of
Water jackets
In the case of large industrial Diesel engines which is started using compressed air direct to the cylinders, when is the air actually admitted to the cylinders
On the power stroke
In which ways might a Diesel engine be started
Hand cranking
Air starter motor
Electric starter
Compressed air delivered to cylinders
What must be done before starting a large Diesel engine?
Prime the fuel injector pump
What problems could a leaking fuel injector cause in a Diesel engine?
Abnormally high exhaust temperatures
Smoky exhaust
VIGV
Variable pitch inlet guide vanes
I thermal combustion engines apply to all
Engines burning off fuel
Internal combustion changes chemical energy in fuel to
Useful heat
What are most common fuels used in an I thermal combustion engine
Natural gas
Gasoline
Light oil fuel
Heavy oil fuel
Natural gas is considered
Environmentally clean
Natural gas is
Readily accessible
Gasoline is
Liquid hydrocarbons enhanced with benzene or Iso-octanes
Gasoline is ___ speed type
High
The process of vaporization is know as
Carburetion
Most modern engines now use
Direct fuel injection
Heavy oil fuel is important in what type of combustion engine
High compression engines
What are the for steps of a four struck ignition cycle
Intake
Compression
Power
exhaust
How is the crankcase lubricated
Pumped under pressure or splashed
Two advantages of Four cycle engines
Good fuel economy and good control at all speeds
Two stroke ignition cycle had no
Valves or camshaft
How is two stroke engine lubricated
My mixing special lubrication with gasoline in the tank
In the carburetor the gasoline is
Vaporized
Two cycle engines are best for
Max power and min size. Best at high engine speeds
In a Diesel engines the fuel is injected at
High pressure directly into the engines cylinder in liquid form (finely atomized)
In Diesel engines ignition takes place with out the aid of a
Spark
List the four stages of a Diesel engine
Suction
Compression
Power
Exhaust
In a two stroke Diesel engine removal is done by
Scavenging
What are the most common methods of air induction
Supercharges and turbochargers
Diesel engines use what type of ignition
Compression
Diesel engines have no
Carburetor
What does a carburetor do
Mix air and fuel
What are the moving parts in a Diesel engine
Piston Connecting rods Crank pins Crankshaft Main bearings
Diesel engine compression ratio
25:1
The fuel for a Diesel engine is
Mechanically atomized by high pressure
An example of an engine which gives high torque at low speeds would be that of a
Four stroke engine
The purpose of a spark plug is
To ignite the fuel air mixture in a gasoline engine
Using a compressed air starting motor is a popular method of starting a
Large stationary Diesel engine
When using compressed air to each cylinder for starting purpose the pressure is approximately
2100KPa
Reduction in sealing qualities between the piston ring and cylinder wall by the lube oil may be the result of
High cooling water temperatures
