Download - HCCI and CAI Engines
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A Seminar Reporton
“HCCI AND CAI ENGINES”by
Saurabh Y. JoshiSubmitted in partial fulfillment of the requirement for the degree of
Bachelor of Engineering (Mechanical)Year 2016-2017
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CONTENT:IntroductionBasics of HCCI & CAIWorking PrincipleCAI Gasoline EngineMethod to Obtain CAIEmission With CAI & SI EngineMeritsDemeritsFuture ScopeConclusionReferences
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INTRODUCTIONHCCI-Homogeneous Charge Compression Ignition
For Diesel Engines
CAI-Controlled Auto-IgnitionFor Gasoline Engines
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Basics of HCCI & CAIHCCI is a form of internal combustion in which fuel and
air are compressed to the point of auto ignition
Spark plug is not required
Creates same power as conventional engines but has high efficiency
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Fig.1 Difference between SI,CI & HCCI Engines
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Working Principle4-stroke engine
1)Suction2)Compression3)Expansion4)Exhaust Compression Stroke : A given concentration of fuel
and air will spontaneously ignite when it reaches its auto-ignition temperature.
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Fig 1. Working of HCCI engine
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CAI Gasoline EnginesCompression ignition in gasoline engines
Requires high compression ratio
Used in dual mode at high load
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METHODS TO OBTAIN CAIResidual gas content or EGRCompression ratioIntake mixture temperatureIntake mixture pressureFuel-air ratioCoolant temperatureInjection timing in gasoline direct injection engines
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EMISSIONS WITH CAI AND SI ENGINE OPERATIONThe NOx emissions with CAI operation are extremely
low.HC emissions were higher as use of very lean mixtures
results in partial misfired combustion increasing HC emissions.
High HC & CO emission.
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Figure 3-Comparison of indicated specific emissions of CAI & SI engine
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MeritsExtremely low NOX emissionsHigh fuel efficiency & High part load efficiencyPossibility of knocking is avoidedNo problems of flame propagation and burn durationFuel flexibility
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DemeritsControlling Ignition Timing over a Range of Speeds and
LoadsSmaller Power OutputCold-Start CapabilityHigh HC and CO emissions
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Challenges of HCCI/CAIControl over HCCI is major problemHigh peak pressure & high heat release rateEngine has to be stronger so heavierLow power rangeHigh carbon monoxide (CO) & Hydrocarbon
(HC) emission
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Future ScopeJapan and European countries have aggressive research and
development (R&D) programs in HCCI, including both public- and private-sector components.
It is announced that: Ford, Nissan, Toyota, Caterpillar, Volvo, VW, General Motors Daimler-Chrysler and Cummins Engine Company have been performing research on HCCI combustion.
Recent research has greatly expanded toward understanding of HCCI, but additional research will be required to resolve the technical barriers, including: control of combustion timing across the load speed map; controlling the heat release for high load operation; cold-start and control during rapid transient states; unburned hydro carbon emissions.
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Companies using HCCI engines
COMPANY MODEL TECHNOLOGYYEAR OF
COMMERSIALISAT
ION
General MotorsSaturn-Aura pHCCI
Test Vehicle is on the
Road
Opel-vectra pHCCI 2015
MercedesDies-otto pHCCI
Test Vehicle is on the
Road
VolkswagenTouran
CCS(Combined
Combustion Spark)2015
GCI(Gasoline
Compression Ignition)
Ford pHCCI 2015
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ConclusionThe HCCI, combustion process is an interesting option to
the conventional SI and CI processes.HCCI engines have the potential to match or exceed the
efficiency of diesel engines without the major challenge of NOx and PM emission control
A high-efficiency, gasoline-fueled HCCI engine represents a major step beyond CRDI engines for light-duty vehicles.
HCCI engines are a promising technology that can help decrease some of our energy issues in the near years.
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REFERENCES [1] SuyinGan, HoonKiat Ng, KarMun Pang,Homogeneous Charge Compression Ignition
(HCCI) combustion:Implementation and effects on pollutants in direct injection diesel engines Applied Energy 88 (2011) 559–567
[2] Xing- Cai Lu, Wei Chen, Zhen Huang A fundamental study on the control of the HCCI combustion and emissions by fuel design concept combined with controllable EGR. Fuel 84 (2005) 1074–1083
[3] H Z HAO, Brunel University West London, UKOverview of CAI/HCCI gasoline engines [4] Sandesh Pokharkar, Shailesh Pansare, Tushar Khandve, Manthan Pagare Review on hcci
engine ijates vol.4, issue no3, March 2016 [5] Swapnil P. Awate, Shreya B. Bhangare, Dhairya S. Deore Homogeneous Charge
Compression Ignition Engines [6]Mohammad Izadi Najafabadi and Nuraini Abdul Aziz Review Article Homogeneous
Charge Compression Ignition Combustion: Challenges and Proposed Solutions Hindawi Publishing Corporation Journal of Combustion Volume 2013, Article ID 783789
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Thank You!!!
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