201A - Engine Fundamentals Flashcards

1
Q

When did the development and construction of the first internal combustion engine start?

A

In the 1700’s

201A pg. 2

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2
Q

Who defined the four-stroke cycle?
When did this take place?

A

Beau De Rochas in 1862

201A pg. 2

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3
Q

Who built the first successful four-stroke compression ignition engine?
When?

A

Dr. Rudolf Diesel in 1895

201A pg. 3

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4
Q

What year did EGR systems begin to be used to meet Tier 2 regulations?

A

2004

201A pg. 4

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5
Q

What happened in 2007 for exhaust emission regulations?

A

Tier 3
DPF & ULSD of 15ppm

201A pg. 4

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6
Q

What happened in 2010 for exhaust emission regulations?

A

Tier 4
SCR & DEF

201A pg. 4

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7
Q

What is the stroke of a piston?

A

Distance the piston moved from TDC to BDC. Determined by the throw of the crankshaft (2x the throw).

201A pg. 9

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8
Q

What is piston displacement?

A

The swept volume of a single cylinder.

Displacement = cylinder area * stroke

201A pg. 10

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9
Q

How is engine displacement calculated?

A

The swept volume of all cylinders. Directly related to the amount of power an engine can produce.

Disp = piston disp. * #cylinders

201A pg. 10

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10
Q

What is compression ratio in an engine cylinder?

A

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

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11
Q

What is volumetric efficiency?

A

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

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12
Q

How thermal efficient is an internal combustion engine?

A

Approximately 36%

Remaining:
7% Overcome friction
27% Cooling system
30% Exhaust system

201A pg. 12

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13
Q

What is indicated horsepower?

A

Theoretical amount of horsepower

201A pg. 13

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14
Q

What is frictional horsepower?

A

Horsepower lost to overcome friction

201A pg. 13

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15
Q

What is brake horsepower?

A

The Usable horsepower measured at the flywheel.

bhp = ihp - fph

201A pg. 13

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16
Q

What is mechanical efficiency?

A

The comparison of brake horsepower and indicated horsepower, represented as a percentage.

ME = bhp/ihp *100

201A pg. 13

17
Q

Does a two-stroke engine have a shorter or longer effective power stroke?

A

Two-stroke has a shorter effective power stroke

18
Q

What is scavenging?

A

The removal of exhaust gasses from the cylinder.

Two-strokes use a positive displacement blower.

Four-strokes use valve overlap.

201A pg. 21

19
Q

What is the effective power stroke of a four-stroke engine?

A

120-140 degrees of crankshaft rotation.

(Longer than a two-stroke power stroke)

201A pg. 24

20
Q

What is the compression ratio of a four-stroke diesel engine?

A

14:1 - 23:1

(Gas engine: 8:1 - 9:1)

201A pg. 26