internal combustion engine

internal combustion engine - Gas Power Cycle Internal...

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Gas Power Cycle - Internal Combustion Engine Otto Cycle
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Otto Cycle P v 1 2 3 4 T s 1 2 3 4 () cycle 34 21 34 12 41 i n 2 3 32 14 1 v 2 3 2 Thermal efficiency of the system: W [( ) ] =1 Q( ) ( ) / 1 For an ideal gas, u=C , 1 1 / 1 Since / v v mu u u u WW uu Q m CT T T T T T C TT T T T η −−− −− == =  −= =   1 2 1 12 1 1 2 /( w h y ? ) 1 . From isentropic compression relation for an ideal gas 1 , where r= is the volume compression ratio k k T T TV V r V = =− • 1-2 isentropic compression • 2-3 constant volume heat transfer • 3-4 isentropic expansion • 4-1 constant volume heat rejection
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Otto Cycle-2 0 3 6 9 12 15 0 20 40 60 80 100 compression ratio thermal efficiency η ( ) r r Thermal efficiency of an Otto cycle, η =− 1 1 1 r k Typical value of r for a real engine: between 7 and 10 • The higher the compression ratio, the higher the thermal efficiency. • Higher r will led to engine knock (spontaneous ignition) problem.
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Improvement of Performance • Increase the compression ratio
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internal combustion engine - Gas Power Cycle Internal...

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