BTE 1013ENGINEERING SCIENCES

9. GAS LAWS AND ENGINE POWER

NAZARIN B. NORDINnazarin@icam.edu.my

GAS LAWSIdeal Gases

Gases are fluids, differing from liquids in that while liquids are practically incompressible and possess a definite volume, gases are readily compressible and can change their volume. The following are three laws which are found to be reasonably obeyed by the so-called permanent gases, e.g. oxygen and nitrogen, at temperatures in the region of room temperature. A gas which is considered to obey these laws exactly is called an ideal gas.

Ideal Gas Law

PV = nRTR – Universal Gas Constant = 8.315 J/(mol K)n (mol) = mass (g) / molecular mass (g/mol)

Avogadro’s Number – number of molecules per moleNA = 6.02 x 1023

PV = NkTk – Boltzmann’s Constant

k = R = 8.315 J/(mol K) = 1.38 x 10-23 J/K

NA = 6.02 x 1023/mole

Boyle’s Law – the volume of a gas is inversely proportional to the pressure applied to it when the temperature is kept constant

V a 1 P

Charles’s Law – the volume of a given amount of gas is directly proportional to the absolute temperature when the pressure is kept constant

V a TT -absolute temperature

Reciprocating Internal Combustion Engine

SME 2423-2006/2007-2

Indicated Mean Effective Pressure, Pi or i.m.e.p. ,

Engine Performance Criteria

Pi =

= i.m.e.p.

Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

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Indicated Power, IP

IP =

Reciprocating Internal Combustion Engine

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Brake Power, BP

Torque, T

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BP=

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= BP/IP

Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

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,(Specific fuel consumption, sfc)

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Volumetric Efficiency, v

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Energy Balance

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Morse Test

Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

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Reciprocating Internal Combustion Engine

SME 2423-2006/2007-2

Reciprocating Internal Combustion Engine

SME 2423-2006/2007-2

Reciprocating Internal Combustion Engine

SME 2423-2006/2007-2

THANK YOU