Internal Combustion Engines

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?