AME T109 Reciprocating Engine Theory (Part Two) Flashcards
On a Two-Stroke Engine, which of the five events occur on the upstroke and which occur on the downstroke?
Five Events:
1) Intake
2) Compression
3) Ignition
4) Power
5) Exhaust
Upstroke:
Intake and Compression
At top of Stroke:
Ignition
Downstroke:
Power and Exhaust
On a Two-Stroke engine, where does the fuel and air enter through?
What third ingredient else is mixed in and why would it be present?
Fuel and Air enters through the crankcase.
Oil is present as well for lubrication purposes.
What are some advantages to the two-stroke engine?
Disadvantages?
Advantages: Light Weight Has no Valve Mechanism No Lubrication System Excellent Power to Weight Ratio Position of Piston has no effect on Operation
Disadvantages:
Lower Dependability
Operator needs to manually mix the Fuel and Oil
BSFC Rating is Less Efficient
On Diesel Engines, what is injected into the cylinder before TDC?
What is generated as a result causing Ignition?
Fuel.
Heat is generated which causes Ignition.
In regards to the Diesel Engine…
(Fill in the Blank & may want to write down.)
a) It is a high ______ engine.
b) This engine utilizes a ______ stroke.
(A ______ power level is used as a result).
c) The compression ratio is ______ to ______
d) The mixture ratio is ______ to ______ while the engine is ______.
e) At idle the ratio could be up to ______.
(In regards to Detonation)
f) Kerosene (Jet Fuel) is less ______ than gas.
g) This fuel does not combust, it ______
h) Less ______ occurs as a result.
Word Bank Below:
1) Wear
2) Longer
3) Burns
4) Lower
5) Volatile
6) 16:1, 22:1
7) 80:1
8) 30:1, 35:1
9) Running
10) Compression
a) Compression
b) Longer, Lower
c) 16:1, 22:1
d) 30:1, 35:1
e) 80:1
f) Volatile
g) Burns
h) Wear
Why was diesel abandoned for aircraft applications?
Far more advancements in gasoline based technologies took place.
What must a Crankcase be strong enough to support?
Horizontally Opposed Engine Cases
A Crankcase must be strong enough to support the loads stemming from the Crankshaft.
Horizontally Opposed Engine Cases:
Passageways are cast into the case for what purpose?
They are cast so that oil may lubricate various parts of the engine.
Horizontally Opposed Engine Cases:
What is it made from?
Cast Aluminum.
Horizontally Opposed Engine Cases:
What method is used to seal the two halves together?
Silk Thread is run along the perimeter of the Crankcase for the purpose of sealing them together.
Radial Engine Crankcases:
What is this Case made of?
Forged Steel Alloy.
Radial Engine Crankcases:
What does this Case support?
The loads produced by the Power Stroke.
Radial Engines:
What is the purpose of the Crankshaft?
To transmit the reciprocating motion to a linear motion.
What threee things does the crankshaft consist of?
Radial Engines
1) Main Journals
2) Crank Cheeks
3) Crank Pins
Radial Engines:
What might be built into the Crank Pins and why?
Crank pins may have sludge tubes built into them to collect any oil impurities.
What does a Radial Engine Crankshaft possess only one of per bank?
A single throw per bank.
The Radial Engine is connected to the Crankshaft and Piston via what?
A Master Link.
Horizontally Opposed Engines:
What two crankshaft types may be used?
180 Degree Crankshaft
60 Degree Crankshaft
What do Dynamic Vibration Dampeners consist of?
Dynamic Balane weights attached to Mounting Blades on the Crankshaft.
Which kind of Crankshaft (in regards to Horizontally Opposed Engines) use Dynamic Vibration Dampeners?
180 Degree Crankshaft Design.
How do Dynamic Vibration Dampeners work?
A force acts in one direction and the balance counters it in the opposing direction.
Horizontally Opposed Engines:
Between the Master and Articulating Rods, which is the most important to the aircraft?
The Master Rod.
Horizontally Opposed Engines:
What kind of connecting is used?
Plain Connecting Rods.
What is the bottom of the Piston called?
The Piston Skirt.
What is the Piston Pin made from?
A Steel Alloy
The Piston Pin is place within what?
The Piston Boss.
What is the purpose of the Piston Pin?
To assist in protecting the Cylinder Walls from scoring.
What are the three possible Propeller Shaft (Crankshaft) designs?
Tapered
Splined
Flanged Type.
What is unique about the Tapered Crankshaft Design?
Has a slot for a woodruff key.
Why does the Tapered Propeller Shaft design limit the propeller to 100 Hp?
The Woodruff Key Slot is a point of weakness.
Propeller Shafts with a woodruff key slot have what limit?
The propeller is limited to 100 Hp.
Describe the Splined Propeller Shaft Design.
It has multiple straight indentations around the circumference.
What is a master Spline in regards to a Splined Propeller Shaft?
It is a indentation that is twice the width or depth of the other straight indentations making up the Propeller Shaft.
What are the four types of Piston Head Designs?
Which is the most common?
Which is utilized in low compression applications?
Which is used for high compression applications?
1) Flat - Most Common
2) Recessed
3) Cup (Concave) - Low Compression Applications
4) Dome (Convex) - High Compression Applications
What differentiates a Cam Ground Piston from just a Piston?
Cam Ground Pistons are ten thousandths of an inch oblong until it reaches operating temperature.
Heat causes expansion which makes the Piston Round.
What is the main purpose of Piston Rings?
What is their secondary purpose?
Their third purpose?
To seal the combustion chamber.
Prevent oil from entering the combustion chamber.
Aids in the dissipation of heat.
What are some of the materials that Piston Rings may be made of?
Cast Iron
Chrome Plated Steel
Chrome Plated Steel may ONLY be used on what kind of Cylinder?
Steel Cylinders.
What are the three kinds of Piston RIng Joint designs?
Butt Joint
Step Joint
Angle Joint
What is the Blow-By Phenomenon?
What causes it?
What alleviates this phenomenon?
Pressure from the ombustion chamber works its way down and into the crankcase.
Occurs due to the improper sealing of the Piston Rings.
A hole exists at the top of the crankcase to allow this pressure to escape.
What are the three types of Piston Rings?
Compression Rings
Oil Control Rings
Oil Scraper Rings
What is the purpose of the Compression Piston Ring?
To seal the combustion chamber.