Ic Engine

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INTERNAL COMBUSTION ENGINES

INTERNAL COMBUSTION ENGINES
Mihir Sen University of Notre Dame

November 11, 2009

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INTERNAL COMBUSTION ENGINES Outline

1 Outline 2 Basics 3 Classification 4 Terminology 5 Components 6 Operation 7 Thermodynamics 8 Parameters 9 Output

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INTERNAL COMBUSTION ENGINES Basics

Historical

Lenoir, 1860: first auto Otto and Langen, 1867: efficiency about 11% Diesel, by 1892: compression ignition engine

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INTERNAL COMBUSTION ENGINES Basics

Combustion engines
Chemical energy in fuel converted to thermal energy by combustion or oxidation Heat engine converts chemical energy into mechanical energy Thermal energy raises temperature and pressure of gases within engine, and gas expands against mechanical mechanisms of engine Combustion Internal: fuel is burned within the engine proper (including e.g. rocket engines, jet Engines, firearms) External: combustion is external to the engine (e.g. steam, Stirling engine, gas turbine)

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INTERNAL COMBUSTION ENGINES Classification

Classification of IC engines
Ignition Number of strokes Valve location Design Position and number of cylinders Air intake Fuel input method Fuel used Cooling Application

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INTERNAL COMBUSTION ENGINES Classification

Ignition

Spark ignition (SI): high-voltage electrical discharge between two electrodes ignites air-fuel mixture in combustion chamber surrounding spark plug Compression ignition (CI): air-fuel mixture self-ignites due to high temperature in combustion chamber caused by high compression, Diesel engine

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INTERNAL COMBUSTION ENGINES Classification

Number of strokes

Four-stroke: four piston movements over two engine revolutions for each engine cycle Two-stroke: two piston movements over one revolution for each engine cycle

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INTERNAL COMBUSTION ENGINES Classification

Valve location

Valves in head Valves in block One valve in head and one in block (less common)

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INTERNAL COMBUSTION ENGINES Classification

Design

Reciprocating Rotary

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INTERNAL COMBUSTION ENGINES Classification

Reciprocating engines

Engine has one or more cylinders in which pistons reciprocate back and forth Combustion chamber in closed end of cylinders Power delivered to rotating output crankshaft by mechanical linkage with pistons

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INTERNAL COMBUSTION ENGINES Classification

Rotary engines
Engine made of block (stator) built around large non-concentric rotor and crankshaft Combustion chambers are built into the nonrotating block

http://www.youtube.com/watch?v=oGrD7FTFLJc

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INTERNAL COMBUSTION ENGINES Classification

Position and number of cylinders
Single cylinder (e.g. lawnmowers) In-line or straight: cylinders in straight line, one behind the other in length of crankshaft V: two banks of cylinders at an angle with each other along a single crankshaft, angle typically 60-90◦ Flat or opposed cylinder (V with 180◦ ): two banks of cylinders opposite each other on a single crankshaft (small aircrafts) W: three banks of cylinders on same crankshaft (not common) Opposed piston engine: two pistons in each cylinder, combustion chamber between pistons Radial engine: cylinders positioned radially around crankshaft

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INTERNAL COMBUSTION ENGINES Classification

In-line

V

Flat

Radial http://en.wikipedia.org/wiki/Radial_engine

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INTERNAL COMBUSTION ENGINES Classification

Air intake

Naturally aspirated: no air pressure boost Supercharged: air pressure increased with compressor driven by crankshaft Turbocharged: air pressure increased by turbine-compressor driven by exhaust gases Crankcase compressed: two-stroke engine with crankcase as intake air compressor

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INTERNAL COMBUSTION ENGINES Classification

Supercharger

Supercharger on AMC V8 engine for dragstrip racing

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INTERNAL COMBUSTION ENGINES Classification

Turbocharger

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