Internal Combustion
Engines
Elena Mayordomo Jenaro
Rafael Herrero Rodrígo
Fernando Alonso
Dani Sordo
What do…
… have in common?
Objectives
• Components and purposes of each
• Types of engines
• How the different engines work
Components of internal combustion engines
Structural components
• Cylinder block: contains holes for the pistons and adaptions to attach the cylinder head, crankcase, drive housing and engine ancillaries, with passages for coolants and lubricants.
• Cylinder head: contains part of the combustion chamber and supports valve train.
• Crankcase: engine frame section that houses the crankshaft.
• Oil sump: reservoir for collecting and holding lube oil.
Moving Components
- Reciprocating only (pistons and valves)
- Reciprocation & rotary (connecting rods)
- Rotary only (crankshafts and camshafts)
• Piston– Acted on by combustion gases– Lightweight but strong/durable
• Piston Rings– Transfer heat from piston to
cylinder– Seal cylinder and distribute lube
oil
• Connecting Rod– Connects piston & crankshaft– reciprocating rotating motion
V-Engine
Straight engine Flat engine
Radial engine
• Crankshaft– Combines work done by each piston– Drives camshafts, generator, pumps, etc.
• Flywheel– Absorbs and releases kinetic energy of piston
strokes smoothes rotation of crankshaft
• Valves– Intake: open to admit air
to cylinder (with fuel in Otto cycle)
– Exhaust: open to allow gases to be rejected
• Camshaft & Cams– Used to time the addition
of intake and exhaust valves
– Operates valves via pushrods & rocker arms
Thermodynamic principles involved
Gasoline engine Diesel engine
Otto cycle Diesel cycle
Spark ignition Compressed ignition
Compresses air-fuel mixture
Compresses air only
Operation of systems• Can be 2 or 4 stroke engines
- 2 stroke: 1 power stroke per 1 crankshaft rev
- 4 stroke: 1 power stroke per 2 crankshaft rev
• Engine stroke- A stroke is a single traverse of the cylinder by the piston (from TDC to BDC)- 1 revolution of crankshaft = 2 strokes of piston
Four-Stroke Diesel Engine• Intake stroke
– Intake valve open, exhaust valve shut– Piston travels from TDC to BDC– Air drawn in
• Compression stroke– Intake and exhaust valves shut– Piston travels from BDC to TDC– Temperature and pressure of air increase
• Power stroke– Intake and exhaust valves shut– Fuel injected into cylinder and ignites– Piston forced from TDC to BDC
• Exhaust stroke– Intake valve shut, exhaust valve open– Piston moves from BDC to TDC– Combustion gases expelled
Start position Intake stroke Compression stroke
Ignition of fuel Power stroke Exhaust stroke
Two-Stroke Diesel Engine
• Compression– Intake and exhaust valves shut– Piston travels from BDC to TDC– Temperature and pressure of air increase
• Power stroke– Intake and exhaust valves shut– Fuel injected into cylinder and ignites– Piston forced from TDC to BDC
Two vs. Four-Stroke Engines
• Two-stroke advantages– Higher power to weight ratio– Less complicated valve train
• Four-stroke advantages– More efficient burning process– As size increases, power-to-weight ratio
improves
Wankel Engine• The Wankel engine is a type
of internal combustion engine which uses a rotary design to convert pressure into a rotating motion .
Now you know how a car can walk…
• Thanks for your attention
Questions?