Date post: | 17-Dec-2015 |
Category: |
Documents |
Upload: | ethelbert-caldwell |
View: | 216 times |
Download: | 2 times |
ReciprocatingEngine Review
Back to School – Spring Break is Over!
Reciprocating Engines
Mechanical SystemCylinder
Known as the engine’s combustion chamber
Where the power is developed
Mechanical SystemPiston
Fits snugly in the hollow cylinder allowing up-and-down linear
(straight) motion
Fit will not allow air or fluid in the cylinder
Mechanical System Crankshaft
• The crankshaft and connecting rod allow for the movement of the propeller.
Mechanical System Connecting Rod
• Attached to the throws
• With the crankshaft, they change the direction of the pistons into a circular motion
Mechanical SystemValves
• A rocker arm regulates the opening and closing of
each valve.
• Lobes or rings on a camshaft push the rocker arm
Spark Plug
• Internal combustion engines are– spark-ignition engines, which
require spark plugs to begin combustion, and
– compression-ignition engines (diesel engines), which compress the air and then inject diesel fuel into the heated compressed air mixture where it auto-ignites.
Mechanical System Cylinder
Piston
Crankshaft
Connecting Rod
Valves
Spark plug
Mechanical System
Four-Stroke Cycle • Occurs at the same time in all
cylinders, but not on the same step
• Ignition sequence of the cylinders called the firing order
Four-Stroke Cycle
Types of Reciprocating Engines
How to get more horsepower from an engine?
(1) Increase the number of cylinders or (2) Increase the size of each cylinder
Attention focused on designs
Types of Reciprocating Engines
In-line Engines
• Cylinders are located in a row, one behind the other
• Two classifications:
• Upright
• Inverted
Types of Reciprocating Engines
Opposed Engines
Two rows or banks of cylinders on each side of the crankshaft
Rows directly opposite each other called horizontal opposed
Types of Reciprocating Engines
V and X Engine
• “V” engine features two rows of cylinders set at an angle of about 45°
• The “X” engine is essentially an opposed “V” engine
Types of Reciprocating Engines
Radial Engine
• Crankshaft with only one throw• Odd number of cylinders in each bank or row • Maximum number of cylinders in each bank is nine
Radial Engine
Construction of Reciprocating Engines
Cylinder andhead of thecylinder
Made of high-grade steel; allow machining to very closespecifications.
Cylinder barrel(body of thecylinder)
Made of cast or forged aluminum alloy and is shrunk onto thecylinder barrel.
Valves Made of tungsten steel or chromium steel which providesstrength at high temperatures.
Pistons Made of forged or cast aluminum.
Crankshaft Made of chromium steel.
Fuels Used in Reciprocating Engines
• Most common form of fuels is hydrocarbons derived from petroleum
• Gasoline and kerosene offer several advantages•Mix easy with air•Low flash point•High heat content - power