about power train technology

1. OVERVIEW OF POWERTRAIN
Mr. B.Harishbabu

2. TRANSPORTATION/MOBILITY
 Transportation/Mobility is a vital to modern economy
 Transport of People
 Transport of goods and produce
 People get accustomed to the ability to travel.
 Mobility is must, but not at the cost of environment

3. EMISSION REQUIREMENTS
1975 1980 1985 1990 1995 2000 2005 2010
0.01
0.1
1
Euro 5
Euro 4
1975
1977
1981
1994 TLEV
1997-2003 ULEV
2004 SULEV2
NOx(g/mile)
Starting year of implementation
Euro 3
1975 1980 1985 1990 1995 2000 2005 2010
0.01
0.1
1
Euro 4
Euro 5
1977
1975
1981 1994 US
1994 TLEV
1997 TLEV
1997-2003 ULEV
2004 SULEV2
NMOG(g/mile)
Starting year of implementation
Euro 3
(Gasoline engines)
Historic trend: Factor of 10 reduction every 15 years

4. ENERGY SOURCE
 Vehicles need to carry source of energy on board
 Hydrocarbons are unparalleled in terms of energy
density
 For example, look at refueling of gasoline
 ~10 Liters in 1 minutes (~0.125 Kg/sec)
 Corresponding energy flow
= 0.125 Kg/sec x 44 MJ/Kg
= 5.5 Mega Watts
Liquid hydrocarbons !

5. TRANSPORTATION ENERGY UTILITY
(DOES NOT INCLUDE MILITARY TRANSPORTATION)
Source: US Dept. of Energy
2003
1970 1980 1990 2000 2010
0
5
10
15
20
25
30
Energyuse(x1015
BThU)
Year
Passenger cars
Light trucks
Heavy
trucks
Non-
Highway
USA

6. INDUSTRY INERTIA
 Capital Penetration
Need for Budget / Financial Approvals
 Technology Penetration
Takes time to develop and implement
Example: Automotive Powertrain
a. Incremental changes: Design needs to be completed 3-4
years before production
b. Significant changes: Add 5-10 years of development time to
(a)
c. Drastic changes: Add 10 to 15 years to (a)
d. Radical changes: Add ? years to (a)
 Market penetration

7. THERMODYNAMIC PRINCIPLES REVIEW
 Thermodynamics is the study of heat related to matter in
motion.
 Heat engine is a mechanical device which convert the heat
energy into mechanical work
7
Engine
11
.
, TQ 22
.
, TQ
.
W

8. REVERSIBLE PROCESS
 Reversible process is the rate of generation of entropy is
always zero (also named as isentropic process).
 Typical reversible processes are
· Constant pressure process · Constant temperature process
· Constant volume process · Adiabatic process
 Reversible process can be approximated by a polytropic
process,
pVn
= Constant
where n is the polytropic index
n = 0 constant pressure process
n = 1 constant temperature process
n = γ adiabatic process
n = constant volume process
8
n=0
n=1
n=∞n=γ
V
P
∞

9. WORK
 If a system exists in which a force at the boundary of the system is
moved through a distance, then work is done by or on the system.
 The work done by the system is
dW = pAdx = pdV
 The total work done
9∫∫ ==
2
1
2
1
pdVdWW

10. ENERGY
 Energy is the capacity a body or substance possesses which
can result in the performance of work.
 Heat is the energy transferred between one body and another
resulted from the temperature difference.
and
 Internal Energy is the energy content resultant from the
consideration of the temperature of a substance.
 Enthalpy
- First Law of Thermodynamics: dq=du+dw=du+pdv=d(u+pv)
- Enthalpy is defined as: h=u+pv
10
∫= dTpcq ∫= dTvcq

11. THERMODYNAMIC GAS CYCLES
Otto Cycle
1 – 2: isentropic compression
2 – 3: constant-volume heat addition
3 – 4: isentropic expansion
4 – 1: constant-volume heat rejection
 Compression ratio
 Heat addition Qin=mcv(T3-T2)
 Heat rejection Qout=mcv(T4-T1)
11
1
4
3
2
V
p
3
4
2
1
V
V
V
V
r ==

12.  Isentropic compression
 Perfect gas pV = mRT
 Isentropic process pVγ
= constant
 Isentropic expansion
 Cycle efficiency
12
γr
p
p
=
1
2 1
1
2 −= γr
T
T
γ








=
rp
p 1
3
4
1
1
3
4
−
= 







γ
rT
T
inQ
outQinQ
inQ
outW
Otto
−
==η
1
11
−
−=
γr

13. DIESEL CYCLE
1 – 2: isentropic compression
2 – 3: constant-pressure heat addition
3 – 4: isentropic expansion
4 – 1: constant-volume heat rejection
 Compression ratio
 Heat addition Qin=mcp(T3-T2)
 Heat rejection Qout=mcp(T4-T1)
 Cut-off ratio
 Cycle efficiency 13
3
4
2
1
V
V
V
V
r ==
1
4
32
V
p
2
3
V
V
=β
( )1
1
1
11
−
−
−
−=
βγ
γβ
γ
η
rDiesel

14. DUAL CYCLE
1 – 2: isentropic compression
2 – 2a: constant-volume heat addition
2a – 3: constant-pressure heat addition
3 – 4: isentropic expansion
4 – 1: constant-volume heat rejection
 Heat addition Qin
=mcv
(T2a
-T2
)+mcp
(T3
-T2a
)
 Heat rejection Qout=mcp(T4-T1)
 Cut-off ratio
 Constant volume heat addition pressure ratio
 Cycle efficiency
14
1
4
3
2
V
p
2a
a
V
V
2
3=β
2
3
p
p
=α
( ) ( )















−+−
−
−
−=
11
1
1
11
βγαα
γαβ
γ
η
rDual

15. FUNCTIONAL REQUIREMENTS OF
ENGINE
15
•Power
•Torque curve
•Speed range
•Duty cycle
•Weight/space
•Reliability
•Durability
•Cost
•Fuel economy
•Emissions
•Noise
•Power takeoff
•Flexibility
•Serviceability
•Recycling
•Other

16. HEAT ENGINE CLASSIFICATION
16
Engines
Internal Combustion Engines External Combustion Engines
Spark Ignition Engines Compression Ignition Engines
Carburettor CFI PFI GDI IDI DI

17. EXTERNAL COMBUSTION ENGINES
 Stirling Engine
17

18. INTERNAL COMBUSTION ENGINES
18
Figure 3-3 Two stroke engine
Two-stroke Engines

19. FOUR-STROKE ENGINES
19

20. SIZES OF ENGINES
The Most Powerful Diesel Engine in the
World!
Some facts on the 14 cylinder version:
 Total engine weight: 2300 tons (The crankshaft
alone weighs 300 tons.)
 Length:89 feet
 Height:44 feet
 Maximum power: 108,920 hp at 102 rpm
 Maximum torque: 5,608,312 lb/ft at 102rpm
20
A 2-stroke medium sized “diesel” engine.
The compression ratio adjusting screw
can be seen at the top pf the of the
cylinder head.
Millimeter-scale rotary MEMS.

21. INTRODUCTION TO SI ENGINE
 In traditional SI engines, the fuel and air are mixed together in the intake system using a
low pressure (circa 2 to 3 bar) fuel injection system (carburettors no longer used).
 Fuel injection system is normally multi-point port injection, which means that there is
one fuel injector (sometimes two) in each inlet port.
 Multi-point injectors normally inject fuel onto the back of the closed inlet valve using
sequential timing with the required amount of fuel quantity being updated by the ECU
every engine event.
21
 Air Fuel Mixture
 Air/fuel Ratio, AFR
 The AFR has a very significant effect on the power output, thermal
efficiency and exhaust emissions and has to be controlled precisely over
the whole operating range.
 All modern engines use an electronic control unit (ECU) and various
sensors and actuators to control the AFR.
 The air to fuel ratio by mass (AFR) is typically 14.3:1 for gasoline fuels.

22. 22
 Spark plug and ignition coil.
 Distributor and distributorless systems
 Combustion Ignition
Instead of one main coil,
distributorless ignitions have a
coil for each spark plug, located
directly on the spark plug itself
 Load Control
 Throttle plate

23. Figure 1.19 Idealised SI engine flame propagation
23
 Spark Ignition Combustion
 Homogeneous mixture of air, fuel and
residual gas.
 Spark ignition shortly before TDC.
 Flame propagation.
 The combustion typically takes 50
degrees of crank angle
 The products of combustion: N2, CO2,
H2O vapour, O2, CO, H2, HCs, NOx.
 Cycle to cycle variation
 knock

24. 24

25. INTRODUCTION TO CI ENGINE
 Air only is drawn into the cylinder during the intake stroke
 Load control is achieved by adjusting the quantity of fuel
injected directly into cylinder
 The in-cylinder charge is stratified
 Peak cylinder pressure is typically limited to 150 bar
25
 General
 Fuel Injection
 Starts just before TDC and continuous until just after TDC.
Fuel quantity injected dependents on the power output
required.
 Line pressure between 400 and 1500 bar
 In-line pump (large diesel engines only),
 Distributor/rotary pump (traditionally used for car engines),
 Unit-injector
 Common-rail (very recent system).
 Common-rail systems are set to displace conventional
jerk pump systems in the near future.
A diesel engine built by MAN AG in 1906

26.  Ignition delay
 Diesel knock
 High Cetane number required
26
 Combustion ignition
 Combustion control

27.  Diesel engines have changed considerably over the last 10
years, the main design trends being:
 Use of DI rather IDI (DI is approximately 20% more fuel
efficient)
 Full electronic control (essential for emission control, economy
and refinement)
 Higher fuel injection pressures up to 1500 bar
(improved emissions)
 Use of common rail injection (much improved control)
 Installation of two-spring injectors (noise reduction)
 Use of 4 valves per cylinder
(improved combustion and emissions)
 Increased used of turbochargers and inter-coolers
(performance and emissions)
 Use of oxidation catalysts
27
 Improvements in Design:

28. COMPARISON OF SI AND CI ENGINES
SI engine
(traditional)
CI engine
Fuel type • Petrol,
• gasoline,
• natural gas,
• methanol, etc.
• Diesel oil,
• vegetable oils,
• MTBE, etc.
Fuel
requirement
High Octane number High Cetane number
Ignition Electrical discharge Compression temperature
Compression
ratio
Typically 8.0 to
12.0:1
Typically 12.0 to 24.0:1
Fuel system Low pressure fuel
injection
High pressure fuel injection
Load control Quantity of govern by
throttle
Quality govern by AFR
Mixture in
cylinder
Homogeneous Stratified
Inlet charge Seldom turbocharged Usually turbocharged
Typical AFR
range
12.0 to 18.0:1 20.0 to 70.0:1
Development
trends
• Direct injection • Common-rail,
• 4 valves,
• full electronic control
Main
advantages
• High specific
power,
• low capital cost
• High thermal efficiency,
• low CO, HC emissions
Main issues • CO2 emissions,
• poor part load
efficiency
• NOx,
• particulate emissions,
• noise
Emission
control
• EGR,
• 3-way catalyst
• EGR,
• injection timing,
• oxidation catalyst
28

29. CONVERGENCE OF S.I. AND C.I.
TECHNOLOGY
Attribute
Fuel Delivery
Air Delivery
Valve Train
EGR
Compression Ratio
29
S.I.
PFI→D.I.
N. Aspirated→Turbo
4V DOHC
Yes
Increasing
C.I.
D.I.
Turbo
4V DOHC
Yes
Decreasing

30. ENERGY SOURCE/VEHICLE SYSTEM
30Fuel-Cell ElectricHydrogen
Shift
Reaction
Plug-In Hybrid ICE
Electric Vehicle
Electricity
Heat
Renewables
(Solar, Wind, Hydro)
Nuclear
EnergyEnergy
CarrierCarrier
PropulsionPropulsion
SystemSystemConversionConversion
Electrification
EnergyEnergy
ResourceResource
ICE Hybrid
Conventional ICE:
Gasoline / DieselLiquid
Fuels
Petroleum FuelsOil
(Conventional)
Oil
(Non-Conventional) Synthetic Fuels (XTL)
Syngas
CO, H2
Fischer
Tropsch
Coal
Natural Gas
1st
and 2nd
Generation Biofuels
Biomass
CriticalDependencyonBatteryTechnology
Source: Shell Group

31. “WELL TO WHEELS” ELECTRIC
POWER FUEL CYCLE
31
Coal Mine
Unit Train
Loader Electric
Vehicle
Transmission
Lines
Coal-Fired Boiler/Steam
Turbine/Generator
Charger/
Service Station
(Conventional Fuel Mix: 50% Coal, 19% Gas, 3% Oil, 19% Nuclear, 9% Non-Fossil Fuel)

32. WELL TO WHEELS EFFICIENCY
32
Source: Argonne National Labs, GM, industry sources

33. 33
Relative CO2 emissions （ Gasoline Eng. = 1 ）
-1.0 -0.5 0 0.5 1 1.5
Otto
Engine
Diesel
Engine
GasolineGasoline
Gasoline-HVGasoline-HV
CNG(LNG)CNG(LNG)
DieselDiesel
FTD(NG)FTD(NG)
FTDFTD
(Biomass)(Biomass)
BDF(Rapeseed)BDF(Rapeseed)
Ethanol(Sugarcane)Ethanol(Sugarcane)
HH22 (NG, on-site)(NG, on-site)
Well to Tank CO2(WTT)
Tank to Wheel CO2(TTW)
@ Japanese 10.15 mode
FC: H2
HH22 (Biomass, on-site)(Biomass, on-site)
WELL TO WHEELS CO2 EMISSIONS
FTD(Coal)FTD(Coal)
EthanolEthanol (Iogen)
HH22 (electrolysis)(electrolysis)
(Cellulose)(Cellulose)
Diesel
Engine
Otto
Engine
Synthetic
Fuel
Source: EUCAR EC-JRC 2006

34. ENERGY PATHWAY FOR A TYPICAL PASSENGER CAR
URBAN (HIGHWAY) FIGURES
Standby
17.2 (3.6) %
Accessories
2.2 (1.5) %
Engine Losses
62.4 (69.2) %
Braking
5.8 (2.2) %
Kinetic
Rolling
4.2 (7.1) %
Aero
2.8 (10.9) %
Drive Line Losses
5.6 (5.4) %
Engine
Fuel
Energy
100%
Drive Line
18.2%
(25.6%)
12.8%
(20.2%)
(Source: Partnership for a New Generation Vehicle (PNGV) Program Plan, July 1994)
Energy sinkEnergy conversion and transmission

35. EFFICIENCY IMPROVEMENTS
Standby
17.2 (3.6) %
Accessories
2.2 (1.5) %
Engine Losses
62.4 (69.2) %
Braking
5.8 (2.2) %
Kinetic
Rolling
4.2 (7.1) %
Aero
2.8 (10.9) %
Drive Line Losses
5.6 (5.4) %
Engine
Fuel
Energy
100%
Drive Line
18.2%
(25.6%)
12.8%
(20.2%)
Engine
opportunity
On demand
accessories
Better transmission
Better
aerodynamics
Better tires, lower
rolling resistance
Vehicle engineering
Regenerative braking
Engine stop
and go
Energy storage element

36. ENGINE OPTIONS
Engine Attributes Drawbacks
SI Engine Well developed Poor sfc at part load
Turbo-charged Diesel Well developed,
good sfc
Cost; emissions
Hybrid Optimized operating
range; regeneration
Cost; battery
Gasoline HCCI On going research
efforts
Diesel HCCI

37. STATE OF ART – ENGINE SYSTEM
37
Other cutting edge design considerations – peak cylinder pressure, fuel injection
pressure, piston speed, valve seating velocity, exhaust temperature limit, etc.

38. SUMMARY
 Powertrain is a complex but interesting
thermodynamic application.
 Supremacy over Powertrain Engineering will lead to
power in your hand.
 There is a convergence of C.I. and S.I. Engine
technologies.
 Alternatives must be compared on a “Well to Wheels”
basis.
 Liquid Hydrocarbon fuels: The dominant fuel source
for many years to come.
 Hybridization / Electrification of engines will
continue to increase.
TRENDS IN POWERTRAIN 2007
38

39. THANK YOU!
39