1

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

2

CONTENT:IntroductionBasics of HCCI & CAIWorking PrincipleCAI Gasoline EngineMethod to Obtain CAIEmission With CAI & SI EngineMeritsDemeritsFuture ScopeConclusionReferences

3

INTRODUCTIONHCCI-Homogeneous Charge Compression Ignition

For Diesel Engines

CAI-Controlled Auto-IgnitionFor Gasoline Engines

4

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

5

Fig.1 Difference between SI,CI & HCCI Engines

6

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.

7

Fig 1. Working of HCCI engine

8

CAI Gasoline EnginesCompression ignition in gasoline engines

Requires high compression ratio

Used in dual mode at high load

9

METHODS TO OBTAIN CAIResidual gas content or EGRCompression ratioIntake mixture temperatureIntake mixture pressureFuel-air ratioCoolant temperatureInjection timing in gasoline direct injection engines

10

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.

11

Figure 3-Comparison of indicated specific emissions of CAI & SI engine

12

MeritsExtremely low NOX emissionsHigh fuel efficiency & High part load efficiencyPossibility of knocking is avoidedNo problems of flame propagation and burn durationFuel flexibility

13

DemeritsControlling Ignition Timing over a Range of Speeds and

LoadsSmaller Power OutputCold-Start CapabilityHigh HC and CO emissions

14

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

15

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.

16

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

17

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.

18

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

19

Thank You!!!

Any Questions?