11. effeciency improvement of various by dinesh kumar sharma
TRANSCRIPT
8/12/2019 11. Effeciency Improvement of Various by Dinesh Kumar Sharma
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By:- Dinesh Kr. Sharma
Lecturer
ME- SKIT
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Contents
IntroductionWorking of Otto cycle engine
Conventional Otto cycle engine
Miller cycle engine
Introduction to Compression Ratio (CR)
Variable Compression Ratio (VCR)engine
Miller cycle engine wit VCR
Computer simulation model
Results
Conclusions
References
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Model Of 4-cylinder Otto ycle En!ine
Working model of Otto Cycle
engine
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Otto Cycle
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Miller Cycle Engine with S-VT (Sequential Valve Timing)
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Is the ratio "y #hich the fuel$air mi%ture is com&ressed
"efore it is i!nited.
Limited in con'entional en!ines due to auto-i!nition.
Determines ho# efficiently the en!ine can utili(e theener!y in the fuel.
) of traditional en!ine is fi%ed and is a com&romise
across a #ide ran!e of o&eratin! conditions.
) for &assen!er cars ran!es "et#een *:+ and +,:+#hile ) for diesel en!ines can "e much hi!her.
What is Compression Ratio (CR)
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Disad'anta!es of 5i%ed )
!ecause CR cannot vary to fit a wide range of
operating conditions"
#ower output is reduced
$uel efficiency is not optimi%ed
#ollution from combustion is not minimi%ed&
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Variable Compression Ratio (VCR)
Wat is it'e combustion camber volume Vc is altered to meet
te power needs to te veicle&
*t low power levels ig CR captures fuel efficiency
benefits&*t ig power levels low CR prevents knock&
CR modified to meet power demand (CR+s range from,"- to .-"-)
Increased fuel efficiencyClaims of up to /01 reduction in fuel consumption
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Miller Cycle !ngine "ith VCRModification in VCR engine by VV&
Miller Cycle wit variable compression ratio&
It as better results tan Miller cycle and Conventional
Otto Cycle in performance&2ess fuel consumption&
Improved efficiency&
3ngine can installed in every sort of veicle&
2ess maintenance&
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Comp#ter Sim#lation Model
Computer model structure for entropy generatin calculation2Bernardo )i"eiro 8or!e Martins9 nt;nio <unes 6,,=3
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!ngine characteristics and "orking conditio
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!ntropy $eneration in engineMain causes of Entropy generation
$ree 34pansionCombustion
5eat transfer
$riction
$low troug valves
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!ntropy generation d#e to Comb#stion
3ntropy generated during combustion corresponds to te
entropy increase due to te cemical reactions inside te
engine cylinder and eat transferred witin te mass ofgas&
*mount of entropy generation is calculated by7
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!ntropy generation d#e to 'eat transfer 6uring working of engine eat is e4canged between te
cylinder carge and te cylinder walls and ten between
te engine and te surrounding environment&
5eat transfer is a significant process during te
combustion and e4pansion stroke&
It is calculated using following formula7
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!ntropy generation d#e to %riction
8eneration of entropy during working of engine occurs
due to internal friction also&
*mount of entropy generated due to $riction is7
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Entropy generated in engine
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Entropy generated in each cycle
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