201A - Engine Fundamentals Flashcards
When did the development and construction of the first internal combustion engine start?
In the 1700’s
201A pg. 2
Who defined the four-stroke cycle?
When did this take place?
Beau De Rochas in 1862
201A pg. 2
Who built the first successful four-stroke compression ignition engine?
When?
Dr. Rudolf Diesel in 1895
201A pg. 3
What year did EGR systems begin to be used to meet Tier 2 regulations?
2004
201A pg. 4
What happened in 2007 for exhaust emission regulations?
Tier 3
DPF & ULSD of 15ppm
201A pg. 4
What happened in 2010 for exhaust emission regulations?
Tier 4
SCR & DEF
201A pg. 4
What is the stroke of a piston?
Distance the piston moved from TDC to BDC. Determined by the throw of the crankshaft (2x the throw).
201A pg. 9
What is piston displacement?
The swept volume of a single cylinder.
Displacement = cylinder area * stroke
201A pg. 10
How is engine displacement calculated?
The swept volume of all cylinders. Directly related to the amount of power an engine can produce.
Disp = piston disp. * #cylinders
201A pg. 10
What is compression ratio in an engine cylinder?
Ratio comparing the volume above the piston at BDC to the volume above the piston at TDC.
CR = (Piston Displacement - Clearance Volume) / Clearance Volume
201A pg. 11
What is volumetric efficiency?
The comparison between the actual amount of air taken into a cylinder during the intake stroke divided by the actual cylinder volume.
A naturally aspirated engine is approx. 85% VE
Reduced by engine design:
- Intake manifold design
- Valve size
- Valve timing
- Plugged air filter
Increased by:
- Turbo
201A pg. 12
How thermal efficient is an internal combustion engine?
Approximately 36%
Remaining:
7% Overcome friction
27% Cooling system
30% Exhaust system
201A pg. 12
What is indicated horsepower?
Theoretical amount of horsepower
201A pg. 13
What is frictional horsepower?
Horsepower lost to overcome friction
201A pg. 13
What is brake horsepower?
The Usable horsepower measured at the flywheel.
bhp = ihp - fph
201A pg. 13
What is mechanical efficiency?
The comparison of brake horsepower and indicated horsepower, represented as a percentage.
ME = bhp/ihp *100
201A pg. 13
Does a two-stroke engine have a shorter or longer effective power stroke?
Two-stroke has a shorter effective power stroke
What is scavenging?
The removal of exhaust gasses from the cylinder.
Two-strokes use a positive displacement blower.
Four-strokes use valve overlap.
201A pg. 21
What is the effective power stroke of a four-stroke engine?
120-140 degrees of crankshaft rotation.
(Longer than a two-stroke power stroke)
201A pg. 24
What is the compression ratio of a four-stroke diesel engine?
14:1 - 23:1
(Gas engine: 8:1 - 9:1)
201A pg. 26
What type of transmission reduces side fumbling through the use of six hydrocoptic marzlevanes fitted to the ambifacient lunar waneshaft?
