1. Next generation CI I C Engines for Automobiles
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
An Unending Search for Best Artificial Beast …..

2. Rudolf Christian Karl Diesel
Diesel published a treatise entitled, Theory and Construction of a Rational Heat-engine to Replace the Steam Engine and Combustion Engines Known Today.
This formed the basis for his work on and invention of, the diesel engine.
In his engine, fuel was injected at the end of compression and the fuel was ignited by the high temperature resulting from compression.

3. Schematic of Combustion in diesel Engine

4. Religious I.C. Engines Diesel Engines quality governed,
 no throttling ,
high CR
High part load fuel economy ….
Low specific power
Low grade fuel, heterogeneous combustion
Turbo-charging – not useful for small engines
High NOx and Smoke (pm)

5. Need for advanced CI combustion concepts
Strict emission regulations
Efficient utilization of energy resources
The conventional diffusion combustion can not meet upcoming stringent emission norms (Higher Smoke and NOx emissions )
Banning of Diesel engines across various Cities world wide regardless of their high efficiency and power out put (e.g. Delhi, Chandigarh)
Emerging topic worldwide to keep the High efficient diesel fuelled vehicles rolling on the roads

6. Various Options for advanced CI combustion
HCCI (Homogeneous Charge Compression Ignition)
RCCI ( Radical Controlled Compression Ignition)
PCCI (Premixed Charge Compression Ignition)
MK combustion (Modulated Kinetics Combustion)
TS combustion (Toyota Soken Combustion)
ATAC (Active Thermo-Atmosphere Combustion)
AR Combustion( Active Radical Combustion)
CAI (Controlled Auto-Ignition)
All of the above concepts are a kind of auto ignition of the fuel.

7. Present scenario
Massive work is going on in top universities and automotive industries across the globe on HCCI combustion to reduce fuel consumption and Emissions
Academia
Nihon Uni., New Ace Inst., Haniyang University, KAIST
Lund Inst., EPFL, IFP, Cambridge, Brunel, UoB, RWTH
Sandia, ORNL, ANL, LLNL, LBNL, Sloan Lab-MIT, ERC-Wisconsin, Stanford
Jiaotong, Jilin Uni.
IIT D, IIT K, IIT M, IISc
Industries
Nippon Soken Corporation, Toyota, Honda, GM, Mercedes-Benz, Volkswagen, TATA Motors

8. Comparison with conventional combustion system
Most of the Fuel & Air Charge Undergoes Compression
High Air Fuel Ratio every where.
Spontaneous Reaction Throughout Cylinder
Low Temperature and Fast Reaction Gives Low NOx

9. Benefits of Advanced CI Combustion
Higher compression ratio and efficiency than SI engines.
Ultra low NOx and particulate emissions which can meet the threshold of next generation emission regulations.
Fuel efficient combustion (saves about 40% fuel than conventional combustion.)
Multi fuel capability (using VCR).
Cost is also less than DI diesel engine as low pressure fuel injection systems are preferred.

10. Critical Issues in Development of Advanced CI Combustion Engines

11. Combustion phasing control strategies
There is no direct control over the combustion timing in concept HCCI engine, unlike CI and SI engines.
State of the art strategies available as of now are
Spark assisted HCCI
Injection assisted HCCI
Retarded main inj.(MULTIDIC)
EGR
Controlling intake air temperature
Variable CR and VVT
Modifying Fuel composition
Water Injection

12. Major Technological Inventions
To address the importance of developing advanced combustion concept for rural application
To develop a cost effective HCCI combustion engine which can switch from HCCI to conventional and vise verse with minimum engine geometry modification.
To implement the same concept to a high speed engine to investigate effect of engine speed and subsequently develop further confidence on our developed method.
To study the effect of various operating parameter on combustion, performance and emission behavior.
To understand knock behavior and combustion stability of Advanced combustion engine.

13. Advanced CI Engine for Next Decade
HCCI-DI Engine.
Divide the fuel into Primary and Pilot Fuel.
Pilot fuel is responsible for homogenization.
Primary fuel is responsible for Compression Ignition.
Identify the conditions for avoidance of Self Ignition due to Pilot fuel Injection.
How to develop a dual injection system????

14. GM's HCCI engines now run from idle to 60 mph!
The basic hardware for a production HCCI engine is in place now, with the only new piece of hardware being a combustion chamber pressure sensor.
GM is continuing to work on the control software to make this a robust system and even adapting the homogeneous charge and pressure sensors to diesel engines to reduce NOx emissions.
The HCCI engine achieves about a 15% improvement in fuel efficiency compared to a similar spark ignition engine at a much lower cost than a hybrid.
GM hopes to have HCCI engines in production in about five years.

15. The Research @IIT Delhi : Schematic test setup
Engine Specifications
Engine type
Single cylinder 4-stroke diesel
Piston type
Bowl type
Bore × Stroke (mm)
116 × 102
Displacement (cc)
950
Max. power (kW)
rev/min
Compression ratio
17.5
Test Conditions
Fuel used
Commercial diesel
Injection pressure (bar)
200
Pilot injection (BTDC)
270°
Main injection (BTDC)
26°
Split ratio (%)
0, 20, 40, 60, 80, 95
Engine speed (rev/min)
1500
Load (IMEP) range (bar)
2 to 6.6 bar

16. Developed HCCI-DI fuel injection system
External pump (Pilot)
2 pumps
Belt drive from extended
cam shaft
Fuel injector
HP pipe 1, 2 and 3
T-junction
Split ratio control lever
Inj. timing control cam
Developed System
Multi injection using single Injector without any geometry modification

17. In-cylinder Processes in a Diesel Engine

18. Modeling of Combustion Process
In above Eq., the rate of the heat loss Qloss/dθ is expressed as:
The convective heat transfer coefficient is given by the Woschni model as
For combustion and expansion processes: C1=