Alternative Powerplants Notes | EduRev

: Alternative Powerplants Notes | EduRev

 Page 1


Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_1.htm[6/15/2012 3:09:31 PM]
 Module 7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
The Lecture Contains:
ALTERNATIVE PROPULSION SYSTEMS
HYBRID ELECTRIC VEHICLES (HEV)
Main Components of HEV
Types of HEVs
FUEL CELL
Fuel Cell Power Output
Factors Favouring Fuel Cell
Fuel Cell Types
Energy Sources for Fuel Cell
Prototype Fuel Cell Vehicles
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 2


Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_1.htm[6/15/2012 3:09:31 PM]
 Module 7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
The Lecture Contains:
ALTERNATIVE PROPULSION SYSTEMS
HYBRID ELECTRIC VEHICLES (HEV)
Main Components of HEV
Types of HEVs
FUEL CELL
Fuel Cell Power Output
Factors Favouring Fuel Cell
Fuel Cell Types
Energy Sources for Fuel Cell
Prototype Fuel Cell Vehicles
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_2.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
ALTERNATIVE PROPULSION SYSTEMS
Following factors provided motivation for the development of alternative propulsion systems for road
vehicles;
Global warming -  Reduction desired in the emission of greenhouse gas, carbon dioxide
Control of urban air pollution
Higher energy efficiency - to prolong availability of petroleum fuels as the crude reserves
are diminishing
Energy security – to be independent of import of energy from other countries
The design of power unit of vehicles is governed by several factors e.g., type of available fuel/energy,
economics of energy availability and environmental considerations. The following vehicle power plants
have been under detailed investigations and some of them are already introduced in the market.
Hybrid - electric propulsion
Fuel cells
Gas turbines
Stirling engine
Batteries for electric vehicle
The hybrid electric and fuel cell vehicles hold a greater promise of practical application.  Hybrid
electric vehicles are built around the existing reciprocating IC engines and some vehicle models are
already in market. The fuel cell vehicle is a zero emission vehicle and all the major auto- companies
are pursuing its development as a future power plant.  Hence, only these two are discussed here.
HYBRID ELECTRIC VEHICLES (HEV)
 Motivating factors for HEV development are;
Power required by vehicle to operate within cities may be around 4 to 7 kW although the rated
engine power ranges from 25 to over 100kW. The engine thus, operates in the city under very
low load conditions giving high fuel consumption and emissions.
Small engine can be employed and operated at constant load and speed at the point of its
maximum efficiency, and another propulsion system can take care of the transient operation.
High vehicle fuel efficiencies are thus, obtained.
Engine  can be tuned to its lowest emissions at the operating load and speed point
Emission control and exhaust after-treatment at steady engine load and speed operation is
more efficient.
Hybrid electric vehicle (HEV) allows achieving precisely this objective.
The hybrid electric vehicle employs two different energy storage and two different propulsion systems:
A conventional propulsion system like IC engine, and
An on-board rechargeable electric energy storage system coupled with electric motor(s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 3


Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_1.htm[6/15/2012 3:09:31 PM]
 Module 7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
The Lecture Contains:
ALTERNATIVE PROPULSION SYSTEMS
HYBRID ELECTRIC VEHICLES (HEV)
Main Components of HEV
Types of HEVs
FUEL CELL
Fuel Cell Power Output
Factors Favouring Fuel Cell
Fuel Cell Types
Energy Sources for Fuel Cell
Prototype Fuel Cell Vehicles
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_2.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
ALTERNATIVE PROPULSION SYSTEMS
Following factors provided motivation for the development of alternative propulsion systems for road
vehicles;
Global warming -  Reduction desired in the emission of greenhouse gas, carbon dioxide
Control of urban air pollution
Higher energy efficiency - to prolong availability of petroleum fuels as the crude reserves
are diminishing
Energy security – to be independent of import of energy from other countries
The design of power unit of vehicles is governed by several factors e.g., type of available fuel/energy,
economics of energy availability and environmental considerations. The following vehicle power plants
have been under detailed investigations and some of them are already introduced in the market.
Hybrid - electric propulsion
Fuel cells
Gas turbines
Stirling engine
Batteries for electric vehicle
The hybrid electric and fuel cell vehicles hold a greater promise of practical application.  Hybrid
electric vehicles are built around the existing reciprocating IC engines and some vehicle models are
already in market. The fuel cell vehicle is a zero emission vehicle and all the major auto- companies
are pursuing its development as a future power plant.  Hence, only these two are discussed here.
HYBRID ELECTRIC VEHICLES (HEV)
 Motivating factors for HEV development are;
Power required by vehicle to operate within cities may be around 4 to 7 kW although the rated
engine power ranges from 25 to over 100kW. The engine thus, operates in the city under very
low load conditions giving high fuel consumption and emissions.
Small engine can be employed and operated at constant load and speed at the point of its
maximum efficiency, and another propulsion system can take care of the transient operation.
High vehicle fuel efficiencies are thus, obtained.
Engine  can be tuned to its lowest emissions at the operating load and speed point
Emission control and exhaust after-treatment at steady engine load and speed operation is
more efficient.
Hybrid electric vehicle (HEV) allows achieving precisely this objective.
The hybrid electric vehicle employs two different energy storage and two different propulsion systems:
A conventional propulsion system like IC engine, and
An on-board rechargeable electric energy storage system coupled with electric motor(s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_3.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
Main Components of HEV
The HEV is an intermediate step between conventional IC engine power train and full electric vehicle.
It has the following main components:
A  prime mover:  IC engines are most commonly used, gas turbine or Stirling engine can also
be used
Electric motor in parallel or series
Electric generator
Battery to store electricity and run motor
Regenerative braking system using devices like flywheel, ultra-capacitor etc.
Power transmission system
The high performance nickel-metal hydride (Ni-MH) batteries are more commonly used as the main
energy storage device. Recently, Lithium-ion (Li- ion) batteries, which have higher energy storage
capacity (˜2.5 kWh/kg) compared to the Ni-MH batteries (˜1.4 kWh/kg) are also being used on some
hybrid vehicles.  To supplement the batteries, other energy storage systems such as flywheel and
ultra or super-capacitors are also used. The flywheel stores energy during vehicle
braking/deceleration and the super-capacitors store energy when the power drawn from the batteries
is low and the excess engine power is available. The super capacitors are capable of generating short
bursts of very high power
Types of HEVs
Two basic types of HEV are
      (i) Series and
     (ii) Parallel type.
Other variants of the two basic types have also been developed. The HEV configurations are shown
in Fig 7.14
Series Hybrid
 In the series hybrid, electric motor is the only propulsion unit. It is connected with the drive wheels.
The engine is coupled with an alternator/ generator that runs the motor as well as charges batteries.
All the energy from the engine to the wheel passes through electric machine and hence, it is called
as series HEV. The electric power is always generated on board. The engine is not required to follow
the transient operation needs of the vehicle.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 4


Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_1.htm[6/15/2012 3:09:31 PM]
 Module 7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
The Lecture Contains:
ALTERNATIVE PROPULSION SYSTEMS
HYBRID ELECTRIC VEHICLES (HEV)
Main Components of HEV
Types of HEVs
FUEL CELL
Fuel Cell Power Output
Factors Favouring Fuel Cell
Fuel Cell Types
Energy Sources for Fuel Cell
Prototype Fuel Cell Vehicles
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_2.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
ALTERNATIVE PROPULSION SYSTEMS
Following factors provided motivation for the development of alternative propulsion systems for road
vehicles;
Global warming -  Reduction desired in the emission of greenhouse gas, carbon dioxide
Control of urban air pollution
Higher energy efficiency - to prolong availability of petroleum fuels as the crude reserves
are diminishing
Energy security – to be independent of import of energy from other countries
The design of power unit of vehicles is governed by several factors e.g., type of available fuel/energy,
economics of energy availability and environmental considerations. The following vehicle power plants
have been under detailed investigations and some of them are already introduced in the market.
Hybrid - electric propulsion
Fuel cells
Gas turbines
Stirling engine
Batteries for electric vehicle
The hybrid electric and fuel cell vehicles hold a greater promise of practical application.  Hybrid
electric vehicles are built around the existing reciprocating IC engines and some vehicle models are
already in market. The fuel cell vehicle is a zero emission vehicle and all the major auto- companies
are pursuing its development as a future power plant.  Hence, only these two are discussed here.
HYBRID ELECTRIC VEHICLES (HEV)
 Motivating factors for HEV development are;
Power required by vehicle to operate within cities may be around 4 to 7 kW although the rated
engine power ranges from 25 to over 100kW. The engine thus, operates in the city under very
low load conditions giving high fuel consumption and emissions.
Small engine can be employed and operated at constant load and speed at the point of its
maximum efficiency, and another propulsion system can take care of the transient operation.
High vehicle fuel efficiencies are thus, obtained.
Engine  can be tuned to its lowest emissions at the operating load and speed point
Emission control and exhaust after-treatment at steady engine load and speed operation is
more efficient.
Hybrid electric vehicle (HEV) allows achieving precisely this objective.
The hybrid electric vehicle employs two different energy storage and two different propulsion systems:
A conventional propulsion system like IC engine, and
An on-board rechargeable electric energy storage system coupled with electric motor(s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_3.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
Main Components of HEV
The HEV is an intermediate step between conventional IC engine power train and full electric vehicle.
It has the following main components:
A  prime mover:  IC engines are most commonly used, gas turbine or Stirling engine can also
be used
Electric motor in parallel or series
Electric generator
Battery to store electricity and run motor
Regenerative braking system using devices like flywheel, ultra-capacitor etc.
Power transmission system
The high performance nickel-metal hydride (Ni-MH) batteries are more commonly used as the main
energy storage device. Recently, Lithium-ion (Li- ion) batteries, which have higher energy storage
capacity (˜2.5 kWh/kg) compared to the Ni-MH batteries (˜1.4 kWh/kg) are also being used on some
hybrid vehicles.  To supplement the batteries, other energy storage systems such as flywheel and
ultra or super-capacitors are also used. The flywheel stores energy during vehicle
braking/deceleration and the super-capacitors store energy when the power drawn from the batteries
is low and the excess engine power is available. The super capacitors are capable of generating short
bursts of very high power
Types of HEVs
Two basic types of HEV are
      (i) Series and
     (ii) Parallel type.
Other variants of the two basic types have also been developed. The HEV configurations are shown
in Fig 7.14
Series Hybrid
 In the series hybrid, electric motor is the only propulsion unit. It is connected with the drive wheels.
The engine is coupled with an alternator/ generator that runs the motor as well as charges batteries.
All the energy from the engine to the wheel passes through electric machine and hence, it is called
as series HEV. The electric power is always generated on board. The engine is not required to follow
the transient operation needs of the vehicle.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_4.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
Parallel Hybrid
In the parallel hybrid, the engine and motor (run by battery) are mechanically connected to wheels
and traction can be provided simultaneously by both the power units. When the engine is unable to
meet the power requirement of the vehicle (such as under acceleration), energy from the battery
supplements the vehicle demand. Engine is thus, subjected to transient demands and consequently
fuel efficiency is poorer and emission penalties occur.
Mixed hybrid
In the mixed hybrid, an alternator run by the engine continues to charge batteries. The power to the
wheels flow directly from the engine as well as from the batteries charged by the alternator
simultaneously as in the parallel hybrids. Toyota Prius car, one of the most successful HEVs is a
mixed hybrid vehicle.
Plug-in hybrid
Most cars run less than 50 to 60 km/day in cities. Thus,  a near zero emission vehicle can be
designed if a  small  size battery pack provides this range during city driving and when the vehicle
needs to run more distance  the IC engine drives the vehicle. The batteries are charged every day by
the mains supply. Such hybrids are called as Plug-in- Hybrid Electric Vehicle (PHEV).
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 5


Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_1.htm[6/15/2012 3:09:31 PM]
 Module 7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
The Lecture Contains:
ALTERNATIVE PROPULSION SYSTEMS
HYBRID ELECTRIC VEHICLES (HEV)
Main Components of HEV
Types of HEVs
FUEL CELL
Fuel Cell Power Output
Factors Favouring Fuel Cell
Fuel Cell Types
Energy Sources for Fuel Cell
Prototype Fuel Cell Vehicles
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_2.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
ALTERNATIVE PROPULSION SYSTEMS
Following factors provided motivation for the development of alternative propulsion systems for road
vehicles;
Global warming -  Reduction desired in the emission of greenhouse gas, carbon dioxide
Control of urban air pollution
Higher energy efficiency - to prolong availability of petroleum fuels as the crude reserves
are diminishing
Energy security – to be independent of import of energy from other countries
The design of power unit of vehicles is governed by several factors e.g., type of available fuel/energy,
economics of energy availability and environmental considerations. The following vehicle power plants
have been under detailed investigations and some of them are already introduced in the market.
Hybrid - electric propulsion
Fuel cells
Gas turbines
Stirling engine
Batteries for electric vehicle
The hybrid electric and fuel cell vehicles hold a greater promise of practical application.  Hybrid
electric vehicles are built around the existing reciprocating IC engines and some vehicle models are
already in market. The fuel cell vehicle is a zero emission vehicle and all the major auto- companies
are pursuing its development as a future power plant.  Hence, only these two are discussed here.
HYBRID ELECTRIC VEHICLES (HEV)
 Motivating factors for HEV development are;
Power required by vehicle to operate within cities may be around 4 to 7 kW although the rated
engine power ranges from 25 to over 100kW. The engine thus, operates in the city under very
low load conditions giving high fuel consumption and emissions.
Small engine can be employed and operated at constant load and speed at the point of its
maximum efficiency, and another propulsion system can take care of the transient operation.
High vehicle fuel efficiencies are thus, obtained.
Engine  can be tuned to its lowest emissions at the operating load and speed point
Emission control and exhaust after-treatment at steady engine load and speed operation is
more efficient.
Hybrid electric vehicle (HEV) allows achieving precisely this objective.
The hybrid electric vehicle employs two different energy storage and two different propulsion systems:
A conventional propulsion system like IC engine, and
An on-board rechargeable electric energy storage system coupled with electric motor(s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_3.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
Main Components of HEV
The HEV is an intermediate step between conventional IC engine power train and full electric vehicle.
It has the following main components:
A  prime mover:  IC engines are most commonly used, gas turbine or Stirling engine can also
be used
Electric motor in parallel or series
Electric generator
Battery to store electricity and run motor
Regenerative braking system using devices like flywheel, ultra-capacitor etc.
Power transmission system
The high performance nickel-metal hydride (Ni-MH) batteries are more commonly used as the main
energy storage device. Recently, Lithium-ion (Li- ion) batteries, which have higher energy storage
capacity (˜2.5 kWh/kg) compared to the Ni-MH batteries (˜1.4 kWh/kg) are also being used on some
hybrid vehicles.  To supplement the batteries, other energy storage systems such as flywheel and
ultra or super-capacitors are also used. The flywheel stores energy during vehicle
braking/deceleration and the super-capacitors store energy when the power drawn from the batteries
is low and the excess engine power is available. The super capacitors are capable of generating short
bursts of very high power
Types of HEVs
Two basic types of HEV are
      (i) Series and
     (ii) Parallel type.
Other variants of the two basic types have also been developed. The HEV configurations are shown
in Fig 7.14
Series Hybrid
 In the series hybrid, electric motor is the only propulsion unit. It is connected with the drive wheels.
The engine is coupled with an alternator/ generator that runs the motor as well as charges batteries.
All the energy from the engine to the wheel passes through electric machine and hence, it is called
as series HEV. The electric power is always generated on board. The engine is not required to follow
the transient operation needs of the vehicle.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_4.htm[6/15/2012 3:09:31 PM]
 Module7:Advanced Combustion Systems and Alternative Powerplants
 Lecture 35:Alternative Powerplants
 
Parallel Hybrid
In the parallel hybrid, the engine and motor (run by battery) are mechanically connected to wheels
and traction can be provided simultaneously by both the power units. When the engine is unable to
meet the power requirement of the vehicle (such as under acceleration), energy from the battery
supplements the vehicle demand. Engine is thus, subjected to transient demands and consequently
fuel efficiency is poorer and emission penalties occur.
Mixed hybrid
In the mixed hybrid, an alternator run by the engine continues to charge batteries. The power to the
wheels flow directly from the engine as well as from the batteries charged by the alternator
simultaneously as in the parallel hybrids. Toyota Prius car, one of the most successful HEVs is a
mixed hybrid vehicle.
Plug-in hybrid
Most cars run less than 50 to 60 km/day in cities. Thus,  a near zero emission vehicle can be
designed if a  small  size battery pack provides this range during city driving and when the vehicle
needs to run more distance  the IC engine drives the vehicle. The batteries are charged every day by
the mains supply. Such hybrids are called as Plug-in- Hybrid Electric Vehicle (PHEV).
 
 
 
 
 
 
 
 
 
 
 
 
 
Objectives_template
file:///C|/...%20and%20Settings/iitkrana1/My%20Documents/Google%20Talk%20Received%20Files/engine_combustion/lecture35/35_4.htm[6/15/2012 3:09:31 PM]
Figure
7.14
Hybrid Electric Vehicle
Systems.
Already a few million HEVs are in use. The gasoline engines used on HEV run on Atkinson cycle to
improve thermal efficiency with large reduction in pumping losses. The Atkinson cycle is implemented
by late closing of intake valve (72 º to 105º after bdc) while keeping the expansion ratio close to 13:1. 
The power output of the engine is increased by supercharging.
The fuel efficiency improvements of nearly 50% in city driving and 30% on combined city and
highway driving have been obtained.
 HEVs have met the SULEV emission standards (NMHC = 0.01, CO = 1.0, NO
x
 = 0.02 g/mile).
HEV powered by diesel engine have obtained 25 % better fuel economy than the comparable
diesel vehicle.  The NO
x
 and PM emissions are lower by nearly   45 and 65 %, respectively.
The diesel hybrids produce up to 50% less CO
2
 than the gasoline engines and 30 to 35% less
than the diesel engines making the diesel-hybrid more fuel efficient and environment friendly
than the gasoline engine hybrid.
 
 
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