A
SEMINAR
ON
“Electric
Hybrid Vehicle”
SUBMITTED
IN PARTIAL FULFILLMENT OF
REQUIREMENT
OF THE DEGEE OF
BACHELOR OF TECHNOLOGY
IN
MECHANICAL ENGINEERING
SUPERVISED BY: SUBMITTED BY:
Prof.
ANSHUL BHATI Devendra Singh
DEPARTMENT OF MECHAICAL ENGINEERING
VYAS COLLEGE OF ENGINEERING AND TECHNOLOGY, JODHPUR
RAJASTHAN TECHNICAL UNIVERSITY, KOTA
2018
CERTIFICATE
This is to certify that the student Mr. Abhinav Singh Charan of final year,
have successfully completed the seminar presentation on “Hybrid Electric Vehicles” towards the partial fulfilment of the
degree of Bachelors of Technology (B. TECH) in the Electrical Engineering of
the Rajasthan Technical University
during academic year 2018 under my supervision.
The work presented in this seminar has not been
submitted elsewhere for award of any other diploma or degree.
Prof.
Anshul Bhati
Supervisor
Professor
Deptt. of ME
Engineering
VIET,
Jodhpur.
Counter
Signed by:
Prof. Manish Bhati
Head Deptt.
of ME Engg.
VIET,
Jodhpur.
ACKNOWLEDGEMENT
First of all, I thank the God Almighty for His grace
and mercy that enabled me in the finalization of this seminar. Secondly I would
also like to thank my Parents and Sister who helped me a lot in finalizing this
project within the limited time frame.
Every seminar big or small is successfully largely
due to effort of a number of wonderful people who have always given their
valuable advice or lent a helping hand. I sincerely appreciate the inspiration,
support and guidance of all those people who have been instrumental in making
this seminar a successful.
I wish to express of gratitude to my guile to Prof. Anshul Bhati, Electrical
Engineering Department to give me guidance at every moment during my entire
thesis and giving valuable suggestion. He gives me unfailing inspiration and
whole hearted co-operation in caring out my seminar work. His continuous
encouragement at each work and effort to the push work are grateful
acknowledged.
I am also grateful to Prof. Manish Bhati, Head of the Department, Electrical Engineering
for giving me the support and encouragement that was necessary for the
completion of this seminar.
Abhinav Singh Charan
ABSTRACT
Have you pulled your car up to the gas/petrol pump
lately and been shocked by the high price of gasoline? As the pump clicked past
Rs1400 or 1500, maybe you thought about trading in that SUV for something that
gets better mileage. Or maybe you are worried that your car is contributing to
the greenhouse effect. Or maybe you just want to have the coolest car on the
block. Currently, there is a solution for all this problems, it's the hybrid
electric vehicle.
The vehicle is lighter and roomier than a purely
electric vehicle, because there is less need to carry as many heavy batteries.
The internal combustion engine in hybrid-electric is much smaller and lighter
and more efficient than the engine in a conventional vehicle. In fact, most
automobile manufacturers have announced plans to manufacture their own hybrid
versions. Hybrid electric vehicles are all around us. Most of the locomotives
we see pulling trains are diesel-electric hybrids. Cities like Seattle have
diesel-electric buses -- these can draw electric power from overhead wires or
run on diesel when they are away from the wires. Giant mining trucks are often
diesel-electric hybrids. Submarines are also hybrid vehicles -- some are
nuclear-electric and some are dieselelectric. Any vehicle that combines two or
more sources of power that can directly or indirectly provide propulsion power
is a hybrid.
TABLE OF CONTANTS
1
Introduction
....................................................................... 1
1.1 Introduction of Hybrid Electric
Vehicle ............................ 1 2
History of Hybrid Electric Vehicle .................................. 3
2.1 History of Hybrid Electric Vehicle
..................................... 3 3 Types by Degree of Hybridization
.................................... 6
3.1
Full Hybrid
........................................................................... 6
3.2
Mild Hybrid
.......................................................................... 7 4
Types of Hybrid Electric Vehicle ......................................
8
4.1
Series Type HEV
................................................................ 8
4.2
Parallel Type HEV
............................................................... 10
4.3
Series-Parallel Type
HEV .................................................... 13 5
Parts of Hybrid Electric Vehicle
..................................... 14
5.1 Engine
.................................................................................
14
5.1.1 Gasoline
Engine .................................................................. 14
5.1.2 Diesel
Engine ......................................................................
14
5.1.3 Hydrogen
Engine ................................................................ 15
5.2
Battery
..................................................................................
16
5.2.1 Batteries
Packaging ............................................................. 17
5.2.2 Basic
Characteristics ........................................................... 19
5.3 Electric
Motor ...................................................................... 21
5.3.1 Motor
Components ............................................................. 21
5.3.2 Components:
Electric Motor – Dc ...................................... 22
5.3.3 Components:
Electric Motor – Ac ...................................... 23
5.4
Controller
.............................................................................
23
5.5
Generator
.............................................................................
24
5.6
Power Split Device
.............................................................. 24
6
Features of Hybrid Electric Vehicle
................................. 25
6.1
Idle Stop ...............................................................................
25
6.2
Regenerative Braking
......................................................... 25
6.3
Power Assist
....................................................................... 26
6.4
Engine-Off Drive
Electric Vehicle Mode ........................... 26
6.5
Plug-In Hybrids
(PHEV) ..................................................... 26
7
Environmental Issues Concerned with HEV
.................. 27
7.1
Environmental Issues
........................................................... 27 8
Features of Hybrid Electric Vehicle ................................. 31
8.1 Starting
and Low Speed Process .......................................... 31
8.1.1
Starting
................................................................................
31
8.1.2
Low Speed Process
............................................................. 31
8.2
Cruising
...............................................................................
32
8.3
Passing ................................................................................
32
8.4
Braking
................................................................................
33
9
Predecessors of Current Technology in HEV
................. 35
9.1
Current Technology
............................................................. 35
10
Advantages and Disadvantages of HEV
.......................... 38
10.1
Advantages
........................................................................... 38
10.2
Disadvantages
...................................................................... 39 11
Modern Hybrids Production .............................................
40
11.1 Modern
Hybrids Production ................................................ 40
Future Works ....................................................................
43
Conclusions
......................................................................... 45
LIST OF FIGURES
2.1 The first
gasoline-electric hybrid vehicle .............................. 3
3.1 Full hybrid
Vehicle-Toyota Prius (2nd generation)............... 6
4.1 Series type
HEV ..................................................................... 9
4.1 Series type
HEV Block Diagram
.......................................... 9
4.3 Power flow in
series type HEV ............................................. 10
4.4 Parallel type
HEV .................................................................. 11
4.5 Parallel type
HEV Block Diagram
....................................... 12
4.6 Power flow in
parallel type HEV ........................................... 12
4.7 Series-
parallel type HEV
..................................................... 13
5.1 Cost per mile
EV v/s Gasoline Engine .................................. 16
5.2 Cylindrical
type battery packaging ........................................ 17
5.3 Prismatic
type battery packaging ........................................... 17
5.4 Button type
battery packaging ............................................... 18
5.5 Pouch type
battery packaging ................................................ 18
5.6 Cycle life
................................................................................
20
5.7 Energy
Densities ....................................................................
20
5.8 Motor Parts
............................................................................ 22
5.9 Components:
Electric Motor – DC ........................................ 23
5.10 Components: Electric Motor – AC
........................................ 23
5.11 Parts of HEV ..........................................................................
24
8.1 Starting and
low speed process of HEV ................................ 31
~ ~
8.2 Cruising
process of HEV ....................................................... 32
8.3 Passing
process of HEV ......................................................... 33
8.3 Braking
process of HEV ........................................................ 34
11.1 1997 Toyota Prius (first generation)
...................................... 42
11.2 2000 Honda Insight (first
generation) .................................... 42
~ ~
Chapter-1
INTRODUCTION
1.1 INTRODUCTION OF HYBRID ELECTRIC VEHICLE
A hybrid vehicle, abbreviated HEV, is one that uses both an
internal combustion engine (ICE) and an electric motor to propel the vehicle.
Most hybrids use a highvoltage battery pack and a combination electric motor
and generator to help or assist a gasoline engine. [1]
The ICE used in a hybrid vehicle can be either gasoline or
diesel, although only gasoline-powered engines are currently used in hybrid
vehicles. An electric motor is used to help propel the vehicle, and in some
designs, capable of propelling the vehicle alone without having to start the
internal combustion engine.
The presence of the electric power train is intended to
achieve either better fuel economy than a conventional vehicle or better performance.
There are a variety of HEV types, and the degree to which they function as EVs
varies as well. The most common form of HEV is the hybrid electric car,
although hybrid electric trucks (pickups and tractors) and buses also exist.
Modern HEVs make use of efficiencyimproving technologies such as regenerative
braking, which converts the vehicle's kinetic energy into electric energy to
charge the battery, rather than wasting it as heat energy as conventional
brakes do. Some varieties of HEVs use their internal combustion engine to
generate electricity by spinning an electrical generator (this combination is
known as a motor-generator), to either recharge their batteries or to directly
power the electric drive motors. Many HEVs reduce idle emissions by shutting
down the ICE at idle and restarting it when needed; this is known as a
startstop system. A hybrid-electric produces less emissions from its ICE than a
comparably-sized gasoline car, since an HEV's
gasoline engine is usually smaller than a comparably-sized pure
gasoline-burning vehicle (natural gas and propane fuels produce lower
emissions) and if not used to directly drive the car, can be geared to run at
maximum efficiency, further improving fuel economy. [1]
Chapter-2
HISTORY OF HYBRID ELECTRIC VEHICLE
2.1 HISTORY OF HYBRID ELECTRIC VEHICLE
In 1900 Ferdinand Porsche
developed the Lohner-Porsche Mixte Hybrid, the first gasoline-electric hybrid
automobile in the world, a 4WD series-hybrid version of "System
Lohner-Porsche" electric carriage previously appeared in 1900 Paris World
Fair. The Mixte included a pair of generators driven by 2.5-hp Daimler IC
engines to extend operating range and it could travel nearly 65 km on battery
alone. It was presented in the Paris Auto Show in 1901. The Mixte broke several
Austrian speed records, and also won the Exelberg Rally in 1901 with Porsche
himself driving. The Mixte used a gasoline engine powering a generator, which
in turn powered electric hub motors, with a small battery pack for reliability.
It had a top speed of 50 km/h and a power of 5.22 kW during 20 minutes. George
Fischer sold hybrid buses to England in 1901; Knight Neftal produced a racing
hybrid in 1902. [2]
Fig. 2.1 The first gasoline-electric
hybrid vehicle
In 1905, Henri Pieper of Germany/Belgium introduced
a hybrid vehicle with an electric motor/generator, batteries, and a small gasoline
engine. It used the electric motor to charge its batteries at cruise speed and
used both motors to accelerate or climb a hill. The Pieper factory was taken
over by Imperia, after Pieper died. The 1915 Dual Power, made by the Woods
Motor Vehicle electric car maker, had a fourcylinder ICE and an electric motor.
Below 15 mph (24 km/h) the electric motor alone drove the vehicle, drawing
power from a battery pack, and above this speed the "main" engine cut
in to take the car up to its 35 mph (56 km/h) top speed. About 600 were made up
to 1918. The Woods hybrid was a commercial failure, proving to be too slow for
its price, and too difficult to service. The United States Army's 1928
Experimental Motorized Force tested a gasoline-electric bus in a truck convoy.
In 1931 Erich Gaichen invented and drove from Altenburg to Berlin a 1/2
horsepower electric car containing features later incorporated into hybrid
cars. Its maximum speed was 25 miles per hour (40 km/h), but it was licensed by
the Motor Transport Office, taxed by the German Revenue Department and patented
by the German Reichs-Patent Amt. The car battery was re-charged by the motor
when the car went downhill. Additional power to charge the battery was provided
by a cylinder of compressed air which was re-charged by small air pumps
activated by vibrations of the chassis and the brakes and by igniting
oxy-hydrogen gas. An account of the car and his characterization as a
"crank inventor" can be found in Arthur Koestler's autobiography,
Arrow in the Blue, pages 269-271, which summarize a contemporaneous newspaper
account written by Koestler. No production beyond the prototype was reported.
The hybrid-electric vehicle did not become widely available until the release
of the Toyota Prius in Japan in 1997, followed by the Honda Insight in
1999.While initially perceived as unnecessary due to the low cost of gasoline,
worldwide increases in the price of petroleum caused many automakers to release
hybrids in the late 2000s; they are now perceived as a core segment of the
automotive market of the future. More than 5.8 million hybrid electric vehicles
have been sold worldwide by the end of October 2012, led by Toyota Motor
Company (TMC) with more than 4.6 million Lexus and Toyota hybrids sold by
October 2012, followed by Honda Motor Co., Ltd. with cumulative global sales of
more than 1 million hybrids by September 2012, and Ford Motor Corporation with
more than 200 thousand hybrids sold in the United States by June 2012.
Worldwide sales of hybrid vehicles produced by TMC reached 1 million units in
May 2007; 2 million in August 2009; and passed the 4 million mark in April
2012.As of October 2012, worldwide hybrid sales are led by the Toyota Prius
lift back, with cumulative sales of 2.8 million units, and available in almost
80 countries and regions. The United States is the world's largest hybrid
market with more than 2.5 million hybrid automobiles and SUVs sold through
October 2012, followed by Japan with more than 2 million hybrids sold through
October 2012 The Prius is the top selling hybrid car in the U.S. market,
surpassing the 1 million milestone in April 2011. Cumulative sales of the Prius
in Japan reached the 1 million mark in August 2011. [2]
Chapter-3
TYPES BY DEGREE OF HYBRIDIZATION
3.1 FULL HYBRID
Full hybrid, sometimes also called a strong hybrid,
is a vehicle that can run on just the engine, just the batteries, or a
combination of both. It uses a gasoline engine as the primary source of power,
and an electric motor provides additional power when needed. In addition, full
hybrids can use the electric motor as the source of population for low-speed,
low acceleration driving, such as stop-and-go traffic or for backing up.Ford's
hybrid system, Toyota's Hybrid Synergy Drive and General Motors/Chrysler's
Two-Mode Hybrid technologies are full hybrid systems The Toyota Prius, Ford
Escape Hybrid, and Ford Fusion Hybrid are examples of full hybrids, as these
cars can be moved forward on battery power alone. A large, highcapacity battery
pack is needed for battery-only operation. These vehicles have a split power
path allowing greater flexibility in the drive-strain by inter-converting
mechanical and electrical power, at some cost in complexity. [3]
Fig. 3.1 Full hybrid Vehicle-Toyota
Prius (2nd generation)
3.2 MILD HYBRID
Mild hybrid, sometimes also called a stop-start
hybrid is a vehicle that cannot be driven solely on its electric motor, because
the electric motor does not have enough power to propel the vehicle on its own.
Stop-start technology conserves energy by shutting off the gasoline engine when
the vehicle is at rest, such as at a traffic light, and automatically
re-starting it when the driver pushes the gas pedal to go forward. Mild hybrids
only include some of the features found in hybrid technology, and usually
achieve limited fuel consumption savings, up to 15 percent in urban driving and
8 to 10 percent overall cycle A mild hybrid is essentially a conventional
vehicle with oversize starter motor, allowing the engine to be turned off
whenever the car is coasting, braking, or stopped, yet restart quickly and
cleanly. The motor is often mounted between the engine and transmission, taking
the place of the torque converter, and is used to supply additional propulsion
energy when accelerating. Accessories can continue to run on electrical power
while the gasoline engine is off, and as in other hybrid designs, the motor is
used for regenerative braking to recapture energy. As compared to full hybrids,
mild hybrids have smaller batteries and a smaller, weaker motor/generator,
which allows manufacturers to reduce cost and weight. Honda's early hybrids
including the first generation Insight used this design, leveraging their
reputation for design of small, efficient gasoline engines; their system is
dubbed Integrated Motor Assist (IMA). Starting with the 2006 Civic Hybrid, the
IMA system now can propel the vehicle solely on electric power during medium
speed cruising. Another example is the 2005-2007 Chevrolet Silverado Hybrid, a
full-size pickup truck. Chevrolet was able to get a 10% improvement on the
Silverado's fuel efficiency by shutting down and restarting the engine on
demand and using regenerative braking. General Motors has also used its mild
BAS Hybrid technology in other models such as the Saturn Vue Green Line, the
Saturn Aura Green line and the Mailbu Hybrid. [3]
Chapter-4
TYPES OF HYBRID ELECTRIC VEHICLE
4.1 SERIES TYPE HEV
In series hybrids, only the electric motor drives
the drive-strain, and the ICE works as a generator to power the electric motor
or to recharge the batteries. The battery pack can be recharged through
regenerative braking or by the ICE. Series hybrids usually have a smaller
combustion engine but a larger battery pack as compared to parallel hybrids,
which makes them more expensive than parallels. This configuration makes series
hybrids more efficient in city driving. The Chevrolet Volt is a series plug-in
hybrid, although GM prefers to describe the Volt as an electric vehicle
equipped with a "range extending" gasoline powered ICE as a generator
and therefore dubbed an "Extended Range Electric Vehicle" or EREV.
Means In a series driveline, only an electric motor is connected to drive the
wheels. In it gasoline motor turns a generator, generator may either charge the
batteries or power an electric motor that drives the transmission and at low
speeds is powered only by the electric motor. In a series-hybrid design, the
engine turns a generator, which can charge batteries or power [4]
an electric motor that drives the transmission. The
internal combustion engine never powers the vehicle directly.
Fig. 4.1 Series type HEV
Fig. 4.2 Series type HEV
This diagram shows the components included in a
typical series hybrid design. The solid-line arrow indicates the transmission
of torque to the drive wheels. The dottedline arrows indicate the transmission
of electrical current. [4]
Fig. 4.3 Power flow in series type
HEV
4.2 PARALLEL TYPE HEV
In parallel hybrids, the ICE and the electric motor
are both connected to the mechanical transmission and can simultaneously transmit
power to drive the wheels, usually through a conventional transmission. Honda's
Integrated Motor Assist (IMA) system as found in the Insight, Civic, Accord, as
well as the GM Belted Alternator/Starter (BAS Hybrid) system found in the
Chevrolet Malibu hybrids are examples of production parallel hybrids. Current,
commercialized parallel hybrids use a single, small (<20 kW) electric motor
and small battery pack as the electric motor is not designed to be the sole
source of motive power from launch. Parallel hybrids are also capable of
regenerative braking and the internal combustion engine can also act as a
generator for supplemental recharging. Parallel hybrids are more efficient than
comparable non-hybrid vehicles especially during urban stop-and-go conditions
and at times during highway operation where the electric motor is permitted to
contribute. Means in a parallel system, both the gasoline and the electric
motor are connected to the drive wheels. Gasoline motor, batteries which powers
an electric motor, both can power the transmission at the same time and
electric motor supplements the gasoline engine. In a parallel-hybrid design,
multiple propulsion sources can be combined, or one energy source alone can
drive the vehicle. The battery and engine are both connected to the
transmission. The vehicle can be powered by internal combustion alone, by
electric motor alone, (full hybrids), or a combination. In most cases, the
electric motor is used to assist the internal combustion engine.
Fig. 4.4 Parallel
type HEV
Fig. 4.5 Parallel type HEV
Diagram showing the components involved in a typical
parallel-hybrid vehicle. The solid-line arrows indicate the transmission of
torque to the drive wheels, and the dotted-line arrows indicate the flow of
electrical current.
Fig. 4.6 Power flow in parallel type
HEV
4.3 SERIES-PARALLEL TYPE HEV
Series-Parallel type also called Power-split hybrids
have the benefits of a combination of series and parallel characteristics. As a
result, they are more efficient overall, because series hybrids tend to be more
efficient at lower speeds and parallel tend to be more efficient at high
speeds; however, the cost of power-split the hybrid is higher than a pure
parallel. Examples of power-split (referred to by some as
"series-parallel") hybrid power-strains include current models of
Ford, General Motors, Lexus, Nissan, and Toyota. Means a series-parallel hybrid
design allows the vehicle to operate in electric motor mode only or in
combination with the internal combustion engine. In it characteristics of both
series and parallel type hybrid electric vehicle are used, it’s cost is more
than both single type HEV’s. [4]
Fig. 4.7
Series- parallel type HEV
Chapter-5
PARTS OF HYBRID ELECTRIC VEHICLE
5.1 ENGINE
It’s much same as other vehicles engine, but the
size of hybrid electric vehicle engine is small and it’s more fuel efficient.
Higher
energy density than batteries,
1,000 pounds of batteries = 1
gallon (7 pounds) of gas. It has three types. [5]
5.1.1 Gasoline engine
Gasoline engines are used in most hybrid electric
designs, and will likely remain dominant for the foreseeable future. While
petroleum-derived gasoline is the primary fuel, it is possible to mix in
varying levels of ethanol created from renewable energy sources. Like most
modern ICE powered vehicles, HEVs can typically use up to about 15%
bio-ethanol. Manufacturers may move to flexible fuel engines, which would
increase allowable ratios, but no plans are in place at present.
5.1.2 Diesel engine
Diesel-electric HEVs use a diesel engine for power
generation. Diesels have advantages when delivering constant power for long
periods of time, suffering less wear while operating at higher efficiency. The
diesel engine's high torque, combined with hybrid technology, may offer
substantially improved mileage. Most diesel vehicles can use 100% pure
bio-fuels (biodiesel), so they can use but do not need petroleum at all for
fuel (although mixes of bio-fuel and petroleum are more common). If
diesel-electric HEVs were in use, this benefit would likely also apply.
Diesel-electric hybrid drive-strains have begun to appear in commercial
vehicles (particularly buses); as of 2007, no light duty diesel-electric hybrid
passenger cars are currently available, although prototypes exist.
5.1.3 Hydrogen engine
Hydrogen can be used in cars in two ways: a source
of combustible heat, or a source of electrons for an electric motor. The
burning of hydrogen is not being developed in practical terms; it is the
hydrogen fuel-cell electric vehicle (HFEV) which is garnering all the
attention. Hydrogen fuel cells create electricity fed into an electric motor to
drives the wheels. Hydrogen is not burned, but it is consumed. This means
molecular hydrogen, H2, is combined with oxygen to form water. 2H2(4e-) + O2
-> 2H2O(4e-). The molecular hydrogen and oxygen's mutual affinity drives the
fuel cell to separate the electrons from the hydrogen, to use them to power the
electric motor, and to return them to the ionized water molecules that were
formed when the electron-depleted hydrogen combined with the oxygen in the fuel
cell. Recalling that a hydrogen atom is nothing more than a proton and an
electron; in essence, the motor is driven by the proton's atomic attraction to
the oxygen nucleus, and the electron's attraction to the ionized water
molecule. [5]
An HFEV is an all-electric car featuring an
open-source battery in the form of a hydrogen tank and the atmosphere. HFEVs
may also comprise closed-cell batteries for the purpose of power storage from
regenerative braking, but this does not change the source of the motivation. It
implies the HFEV is an electric car with two types of batteries. Since HFEVs
are purely electric, and do not contain any type of heat engine, they are not
hybrids. [5]
Fig. 5.1 Cost per mile EV v/s
Gasoline Engine
5.2 BATTERY
It stores the energy generated from gasoline engine
or during regenerative braking, from the electric motor. It’s power the vehicle
at low speed, it’s size is larger and holds much more energy than non-hybrid
electric vehicle. [5]
n Batteries
rule the performance of the vehicle
• They
dictate how much power you get (kW)
• They
dictate how much energy you get (kWh)
n A
single cell dictates the battery voltage each cell mates two dissimilar
materials
Table 5.1 Battery types
5.2.1 Batteries packaging
1. Cylindrical
Fig. 5.2 Cylindrical type battery
packaging
2. Prismatic
Fig. 5.3 Prismatic type battery
packaging
3. Button
Fig. 5.4 Button type battery
packaging
4. Pouch
Fig. 5.5 Pouch type battery packaging
5.2.2 Basic Characteristics
n State
of Charge (SOC)
• Measured
as a percentage of total battery energy (0-100%)
• Typically,
should not go below 20% n Depth of Discharge
(DoD)
• Inverse
of SOC
• Power
(kW)
• Energy
(kWh)
• A-h
n Typically
used for power batteries
• Cells
often described in mA-h n C Rate
• A
normalized rate of power use to qualify testing
• 100%
discharge divided by the time in hours
• C2
means the discharge rate was 100% in ½ hour
• C/2
means the rate was less aggressive – over 2 hours n Cycle
Life
• Always
measured based on DoD
• Ex.
1000 cycles at 80% DoD
Fig. 5.6 Cycle life
n Weight/Volume
• Measures
in terms of W/kg and W-h/kg
• W/l
and W-h/l
Fig. 5.7 Energy Densities
5.3 ELECTRIC MOTOR
It’s power the vehicle at low speed and assist the gasoline
engine when additional power is needed, it’s also convert otherwise wasted
energy from braking into electricity and store it in battery. Most of the
electric machines used in hybrid vehicles are brushless DC motors (BLDC).
Specifically, they are of a type called an interior permanent magnet (IPM)
machine (or motor). These machines are wound similarly to the induction motors
found in a typical home, but (for high efficiency) use very strong rare earth
magnets in the rotor. These magnets contain neodymium, iron and boron, and are
therefore called Neodymium magnets. The magnet material is expensive, and its
cost is one of the limiting factors in the use of these machines.
5.3.1 Motor components
v
Rotating components [1]
Shaft
[2]
Rotor
[3]
Rotor fins
[4]
Fan
v
Housing components
[5]
End bells / bearing housings
[6]
Stator housing
[7]
Cooling fins
[8]
Junction box
[9]
Fan shroud
v
Fixed components
[10] Seals
[11]
Stator windings
[12]
Core iron / lamination stack
[13]
Bearings
Fig. 5.8 Motor Parts
5.3.2 Components: Electric Motor – DC
Fig. 5.9 Components: Electric Motor –
DC
5.3.3 Components: Electric Motor – AC
Fig. 5.10 Components: Electric Motor
– AC
5.4 CONTROLLER
The controller is used to charge
the battery or to supply the power to electric motor.
Ø Converts
Battery DC to a chopped DC power
Ø Can
chop in amplitude (DC) or frequency (AC)
Ø Power
is based on low voltage input signal 4-20 mA or 0-5V
Ø In
other fields this is called a drive or inverter
§ Variable
Frequency (AC)
§ Pulse
Width Modulation (AC)
§ Buck
Conversion (Reduce - DC)
§ Boost
Conversion (Increase - DC)
5.5 GENERATOR
It converts mechanical energy from engine into
electrical energy, which can be used by electric motor stored in the battery.
It’s also used to start the gasoline engine instantly. [5]
5.6 POWER SPLIT DEVICE
It’s a gearbox connecting the gasoline engine,
electric motor and generator. It allows the engine and motor to power the car
independently or in tandem and allows the gasoline engine to charge the
batteries or provide power to the wheels as needed
Fig. 5.11
Parts of HEV
Chapter-6
FEATURES OF HYBRID ELECTRIC VEHICLE
6.1 IDLE STOP
Idle stop turns off engine when the vehicle is
stopped. When the brake is released, the engine immediately starts. This
ensures the vehicle is not using fuel, not creating CO2 emissions, when the
engine is not required to propel the vehicle. At this time battery supply the
power to all accessories of vehicle like AC, DVD Player etc. [6]
6.2 REGENERATIVE BRAKING
Regenerative braking converts otherwise wastage
energy from braking into electricity and store it in the battery. In
regenerative braking the electric motor is reversed so that, instead of using
electricity to turns the wheels, the rotating wheels turns the motor and create
electricity. Using energy from the wheels to turn the motor slows the vehicle
down. When decelerating, the braking system captures energy and stores it in
the battery or other device for later use, helping to keep batteries charged.
In motor
case “𝑬𝒃 = V - 𝑰𝒂𝑹𝒂 “ Generally
𝐸𝑏 <
V
Here, 𝐸𝑏 = Back emf of motor
V = Terminal voltage/Load side
voltage
𝐼𝑎
= Armature current and
Ra = Armature resistance
But in regenerative braking system 𝐸𝑏 >
V, means the load supplies the power to motor.
6.3 POWER ASSIST
The electric motor provides extra power using
current drawn from the battery to assist ICE during acceleration. This
power-assist mode enables the vehicle to use a smaller, more fuel-efficient
engine without giving up performance.
[6]
6.4 ENGINE-OFF DRIVE ELECTRIC VEHICLE MODE
In this mode the electric motor propels the vehicle
at lower speeds. The ICE is not being used during low acceleration, no fuel is
being used and no emissions are being released. When the hybrid is in this
mode, it is essentially in an electric vehicle.
6.5 PLUG-IN HYBRIDS (PHEV)
A plug-in hybrid electric vehicle (PHEV), also known
as a plug-in hybrid, is a hybrid electric vehicle with rechargeable batteries
that can be restored to full charge by connecting a plug to an external
electric power source. A PHEV shares the characteristics of both a conventional
hybrid electric vehicle, having an electric motor and an internal combustion
engine; and of an all-electric vehicle, also having a plug to connect to the
electrical grid. PHEVs have a much larger all-electric range as compared to
conventional gasoline-electric hybrids, and also eliminate the "range
anxiety" associated with all-electric vehicles, because the combustion
engine works as a backup when the batteries are depleted.
Plug-in hybrid vehicles (PHEV) present a cleaner
alternative to traditional vehicles, as they use less oil and have lower
emissions. PHEVs also use less oil than standard hybrid electric vehicles
(HEV), and at first glance seem to have lower emissions than HEVs. PHEV with a
range of 40 miles would have approximately half the emissions of a HEV if it
were powered by a carbon-free energy source, but would have higher emissions if
50% of its electric power was generated by coal. [6]
The Chevrolet Volt is a plug-in
hybrid able to run in all-electric mode up to 35 miles.
Chapter-7
ENVIRONMENTAL ISSUES CONCERNED WITH HEV
7.1 ENVIRONMENTAL ISSUES
Since the dawn of the modern era,
consumption and distribution of energy has quickly become mankind’s highest
priority. However, the continued apathetic attitude that was initially taken
toward energy and its side effects can no longer be used. A new more environmentally
friendly source of energy has to be utilized in order to fulfil our own needs
otherwise we self-destruction while relying on nonrenewable oil based methods.
In the last few decades two new technologies have emerged; the development and
implementation of Hybrid Electric Vehicles (HEVs) and more recently the Plug-in
Hybrid Electric Vehicles (PHEVs). These emerging technologies may make it
possible for the United States to adapt these technologies on a larger scale to
reduce harmful emissions and cut our dependence on foreign oil dramatically.
However, the future of the technologies will heavily depend on the everyday
American consumer’s willingness to forgo the ‘tried and true’ combustion engine
for the infantile technologies of the HEV and PHEV. With the introduction and
continued popularity of HEVs and as well as the recent hype over the PHEVs, the
future of transportation in the United States is on the brink of change. This
project has objectives relevant to the aforementioned HEVs and PHEVs. First,
verify if independence of foreign oil is truly a possibility and how to
accomplish this feat. Second, identify the major motivators for the American
consumers who purchase these vehicles and how that can be used to increase the
sales of HEVs and PHEVs respectively. The third and last objective is to
determine the future impact of the all-electric vehicle (EV). Earlier
civilizations relied on a number of power sources such as water to turn wheels,
to run mills, fire to heat water and create steam, or windmills to turn
grinding stones. Since roughly the 17th century various forms of oil have been
used, such as kerosene, as fuel for lanterns. Even into the 18th, 19th, and
early 20th centuries whales were hunted for their blubber which could be
converted into oil among other things. In the more recent years with the
invention of the combustion engine, which has not only increased the shear
amount of oil consumed annually but also drastically augmented our dependence
upon it in our daily lives. Our oil ‘addiction’ has lead us to the realization
that our usage has its limits, not only does the environment suffer adverse
effects because of its use but our society is so dependent upon that if it were
suddenly removed, most of modern society would cease to function properly if it
all. Without a reasonable alternative this fate is all too possible and this
has caused huge concerns over how, on a large scale, we can change our
consumption habits and create a cleaner energy for our use. Hybrid cars have
come a long way in the past 20 years, but most people are unaware they have
been around since the mid-1800s. The early electric vehicles at the turn of the
20th century were expensive, problematic and not very powerful. Given certain
weather conditions or too steep a hill the electric vehicle of yesteryear was
simply unable to perform up to our expectations. With the introduction of the
Ford Model T, a revolution in vehicles was made. The Model T was cheaper and more powerful and
was made relatively simplistic, it also ran on a then abundant source of
gasoline, and the United States could meet its own internal demand enough so
that it actually exported its excess to European countries such as France and
Britain. Ultimately, the Model T made the early EVs defunct and as such fell
off the radar until events like the 1973 oil crisis and 1979 energy crisis
where the electric technologies were eventually reconsidered. The first
electric car is claimed to have been built between 1832 and 1893 by Robert
Anderson of Scotland. From then until the late 1800s, when they became
efficient enough to use as taxi cabs in England, the cars were heavy, slow and
impractical. Modern batteries development in the early 1900s pushed the
development of more efficient, reliable, and practical electric cars in that
period. The Hybrid came about in 1900 in Belgium, when a small gasoline engine
was paired with an electric motor. During normal operation the electric motor
charged on-board batteries, but during acceleration and uphill stints the electric
motor provided a boost to the 3.5 horsepower motor. In 1905 H Piper patented
the first hybrid in America. In 1910 a hybrid truck was manufactured in
Pennsylvania, which used a 4 cylinder to power a generator and an electric
motor. 1916 saw the production of hybrid cars claiming 35 mph and 48 mpg,
however this also saw the end of the electric car era due to the advances in
combustion engine technology. Until the mid to late 1960s, there is little
commercial advance in hybrid or electric cars. As early as the mid-1960s
congress recognized the importance of reducing emissions to improve air
quality, and that the use of electric cars was a possible way to achieve this.
In the late 60s and early 70s the oil embargo sparked a renewed interest in
hybrid and electric vehicles. A few hybrids were released by major
manufacturers, but most were underpowered and small. More importantly, three
scientists patented the first modern hybrid system in 1971, much of which
closely resemble the hybrids of today. The next big push from congress come s
with the 1976 Electric and Hybrid Vehicle Research, Development, and
Demonstration Act which encouraged the commercial improvement of electric
motors and other hybrid components. The research lead toward new developments
and new vehicle released in the United States, including all electrics from GM
and Honda, even including an electric truck, the Chevrolet S-10. These vehicles
reached a niche group, but still did not receive the sales numbers to be
feasible. This all changed with the release of the Toyota Prius in Japan in
1997. With 18000 sold in the first year it becomes the first economically
feasible hybrid produced. With its import to the united stated in 2000 and the
release of Hondas Insight to the US in 1999 the hybrid age had finally arrived.
However, PHEVs and HEVs are not without limitations, which are mainly caused by
the current state of battery technology. With future research and development
into creating improvements on battery technology many of the limitations will
be greatly reduced if not expunged completely. We have come a long way since
the nickel and lead batteries of the 1960s, more recently the
Nickel Metal Hydride and Lithium Ion battery
technologies have been developed and successfully implemented. Today’s HEVs are
a far cry from the small four horse power models of the 1800s, modern HEVs
include the same power, acceleration, comfort, and price of their counterpart
conventional cars (CVs), but can reach upwards of 50 miles per gallon depending
on the model. The importance of this project is not simply limited toward the
contemporary state of the automotive industry. It is also a generalized
overview of what to expect in the near future concerning the status of the
global automotive market and the respective technologies of which it
encompasses. Valuable insight given into possible implications of using the
aforementioned technologies and how they may affect the US and its ability to
reach its energy goals all while becoming both more energy independent and environmentally
conscious. Projections for the future give an overall view of what is to come,
including future vehicles available for purchase, their collective impact on
the populace, and how that technology can be built upon and advanced. It is
essentially a forecast of the automotive industry from both a national and
global level. Based on the examination of information and projection from
qualified data sources, it gives as full as possible understanding to the
reader of where, when, and how the automotive industry is now and in the
foreseeable future. [6]
Chapter-8
WORKING OF HYBRID ELECTRIC VEHICLE
8.1 STARTING AND LOW SPEED PROCESS
8.1.1 Starting
When hybrid electric vehicle is initially started
the battery typically powers all the accessories of vehicle. The gasoline
engine only starts if battery needs to be charged or the accessories require
more power than available from the battery. [6]
8.1.2 Low speed process
For initial acceleration and
slow-speed driving, as well as reverse, the electric motor uses electricity
from the battery to power the vehicle. If the battery needs to be recharged,
the generator starts the engine and converts energy from engine into
electricity, which is stored in the battery.
|
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Fig. 8.1 Starting and low speed
process of HEV
8.2 CRUISING
To run the vehicle at the speed of above mid-range
for long period (Long drive). At the time of cruising both internal combustion
engine and electric motor are used to propel the vehicle. The gasoline engine
provides the power to the electric vehicle directly and to the electric motor
via the generator. [6]
The generator also converts the
energy from internal combustion engine into electricity and send it to battery
for storage.
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Fig.
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8.2
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Cruising
|
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process
of HEV
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8.3 PASSING
To pass or overtake any other vehicle. During heavy
accelerating or when additional power is needed, the gasoline engine and
electric motor are both used to propel the vehicle. Additional energy from the
battery may be used to power the vehicle.
|
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Fig.
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8.3
|
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Passing
|
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process of
HEV
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8.4 BRAKING
Regenerative braking converts otherwise wastage
energy from braking into electricity and store it in the battery. In
regenerative braking the electric motor is reversed so that, instead of using
electricity to turns the wheels, the rotating wheels turns the motor and create
electricity. Using energy from the wheels to turn the motor slows the vehicle
down. When decelerating, the braking system captures energy and stores it in
the battery or other device for later use, helping to keep batteries charged.
In motor
case “Eb = V - IaRa “ Generally
Eb
< V
Here, Eb = Back e.m.f
of motor
V = Terminal voltage/Load side
voltage
Ia = Armature
current and
Ra = Armature resistance
But in regenerative braking system Eb > V, means the
load supplies the power to motor.
If additional stopping power is
required, we apply friction bakes like disk brakes to stop the vehicle.
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Fig.
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8.3
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Braking
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process
of HEV
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Chapter-9
PREDECESSORS OF CURRENT TECHNOLOGY IN HEV
9.1 CURRENT TECHNOLOGY
A more recent working prototype
of the HEV was built by Victor Wouk (one of the scientists involved with the
Hennery Kilowatt, the first transistor-based electric car). Wouk's work with
HEVs in the 1960s and 1970s earned him the title as the
"Godfather of the Hybrid". Wouk installed
a prototype hybrid drive-strain (with a 16 kilowatts (21 hp) electric motor)
into a 1972 Buick Skylark provided by GM for the 1970 Federal Clean Car
Incentive Program, but the program was stopped by the United States
Environmental Protection Agency (EPA) in 1976 while Eric Stork, the head of the
EPA's vehicle emissions control program at the time, was accused of a prejudicial
cover-up.
The regenerative braking system, the core design
concept of most production HEVs, was developed by electrical engineer David
Arthurs around 1978, using off-the shelf components and an Opel GT. However,
the voltage controller to link the batteries, motor (a jet-engine starter
motor), and DC generator was Arthurs'. The vehicle exhibited 75 miles per US
gallon (3.1 L/100 km; 90 mpg-imp) fuel efficiency, and plans for it (as well as
somewhat updated versions) are still available through the Mother Earth News
web site. The Mother Earth News' own 1980 version claimed nearly 84 miles per
US gallon (2.8 L/100 km; 101 mpg-imp).
In 1989, Audi produced its first
iteration of the Audi Duo (the Audi C3 100 Avant
Duo) experimental vehicle, a plug-in
parallel hybrid based on the Audi 100 Avant
Quattro. This car had a 9.4 kilowatts (12.8 PS; 12.6
bhp) Siemens electric motor which drove the rear road-wheels. A trunk-mounted
nickel-cadmium battery supplied energy to the motor that drove the rear wheels.
The vehicle's front roadwheels were powered by a 2.3 litre five-cylinder petrol
engine with an output of 100 kilowatts (136 PS; 134 bhp). The intent was to
produce a vehicle which could operate on the engine in the country, and
electric mode in the city. Mode of operation could be selected by the driver.
Just ten vehicles are believed to have been made; one drawback was that due to
the extra weight of the electric drive, the vehicles were less efficient when
running on their engines alone than standard Audi 100s with the same engine.
Two years later, Audi, unveiled the second duo
generation, the Audi 100 Duo likewise based on the Audi 100 Avant quattro. Once
again, this featured an electric motor, a 21.3 kilowatts (29.0 PS; 28.6 bhp)
three-phase machine, driving the rear road-wheels. This time, however, the rear
wheels were additionally powered via the Torsen centre differential from the
main engine compartment, which housed a 2.0 litre four-cylinder engine.
[citation needed]
In 1992, Volvo ECC was developed by Volvo. The Volvo
ECC was built on the Volvo 850 platform. In contrast to most production
hybrids, which use a gasoline piston engine to provide additional acceleration
and to recharge the battery storage, the Volvo ECC used a gas turbine engine to
drive the generator for recharging.
The Clinton administration initiated the Partnership
for a New Generation of Vehicles (PNGV) program on 29 September 1993, that
involved Chrysler, Ford, General Motors, USCAR, the DoE, and other various
governmental agencies to engineer the next efficient and clean vehicle. The
United States National Research Council (USNRC) cited automakers' moves to
produce HEVs as evidence that technologies developed under PNGV were being
rapidly adopted on production lines, as called for under Goal 2. Based on
information received from automakers, NRC reviewers questioned whether the
"Big Three" would be able to move from the concept phase to cost
effective, pre-production prototype vehicles by 2004, as set out in Goal 3. The
program was replaced by the hydrogen-focused Freedom CAR initiative by the
George W. Bush administration in 2001, an initiative to fund research too risky
for the private sector to engage in, with the long-term goal of developing
effectively carbon emission- and petroleum-free vehicles.
1998 saw the Esparante GTR-Q9 became the first
Petrol-Electric Hybrid to race at Le Mans, although the car failed to qualify
for the main event. The car managed to finished second in class at Petit Le
Mans the same year. [7]
Chapter-10
ADVANTAGES AND DISADVANTAGES OF HEV
10.1 ADVANTAGES
a) Hybrid
cars emit up to 90% less toxic emissions and half as much greenhouse-this
causes carbon dioxide as an average car (therefore drivers would not have to
worry about polluting the environment).
b) Hybrids
can run on electricity or gas.
c) Less
fuel consumption. Current HEVs reduce petroleum consumption under certain
circumstances, compared to otherwise similar conventional vehicles, primarily
by using three mechanisms:
} Reducing
wasted energy during idle/low output, generally by turning the ICE off
} Recapturing
waste energy (i.e. regenerative braking)
} Reducing
the size and power of the ICE, and hence inefficiencies from under-utilization,
by using the added power from the electric motor to compensate for the loss in
peak power output from the smaller ICE. Any combination of these three primary
hybrid advantages may be used in different vehicles to realize different fuel
usage, power, emissions, weight and cost profiles. The ICE in an HEV can be
smaller, lighter, and more efficient than the one in a conventional vehicle,
because the combustion engine can be sized for slightly above average power
demand rather than peak power demand. The drive system in a vehicle is required
to operate over a range of speed and power, but an ICE's highest efficiency is
in a narrow range of operation, making conventional vehicles inefficient. On
the contrary,
in most HEV designs, the ICE
operates closer to its range of highest efficiency more frequently. The power
curve of electric motors is better suited to variable speeds and can provide
substantially greater torque at low speeds compared with internal-combustion
engines. The greater fuel economy of HEVs has implication for reduced petroleum
consumption and vehicle air pollution emissions worldwide.
d) The
battery pack of a hybrid vehicle never needs to be charged from an external
source. It’s charged by ICE and by motor from braking system.
e) Hybrids
have smaller engines; therefore, they tend to weigh less than nonhybrids (but
this can lead to problems in the future). Since hybrid cars can run on
alternative fuels, this allows us to decrease our dependency on fossil fuel and
enables us to increase fuel options. (hybrids reduce fuel costs). [7]
f) A
person who purchases a hybrid car is entitled to a federal tax deduction.
10.2 DISADVANTAGES
a) Hybrids
are more expensive than non-hybrids. The cost of HEV is more because it’s using
more parts than non-HEV and these all are costly.
b) It
requires more maintenance. It’s using more parts so all require more
maintenance.
c) It
has low towing capacity. It’s engine size is small so it’s don’t able to import
and export more things.
d) The
parts that make up the hybrid car are more expensive and are more difficult to
acquire for one’s car.
e) Since
a hybrid is electrical, Water cannot be used to put out a fire that starts in
the hybrid.
f) Hybrids
(in regards to a car accident) have a much higher risk of exploding (depending
on the impact of the vehicle) because it has a combination of gasoline and
ethanol (which are both highly flammable).
[7]
Chapter-11
MODERN HYBRIDS PRODUCTION
11.1 MODERN HYBRID PRODUCTION
Automotive hybrid technology became widespread
beginning in the late 1990s. The first mass-produced hybrid vehicle was the
Toyota Prius, launched in Japan in 1997, and followed by the Honda Insight,
launched in 1999 in the United States and Japan. The Prius was launched in
Europe, North America and the rest of the world in 2000. The first generation
Prius sedan has an estimated fuel economy of 52 miles per US gallon (4.5 L/100
km; 62 mpg-imp) in the city and 45 miles per US gallon (5.2 L/100 km; 54
mpg-imp) in highway driving. The two-door first generation Insight was
estimated at 61 miles per US gallon (3.9 L/100 km; 73 mpg-imp) miles per gallon
in city driving and 68 miles per US gallon (3.5 L/100 km; 82 mpg-imp) on the
highway.
The Toyota Prius sold 300 units in 1997, 19,500 in
2000, and cumulative worldwide Prius sales reached the 1 million mark in April
2008. By early 2010, the Prius global cumulative sales were estimated at 1.6
million units. Toyota launched a second generation Prius in 2004 and a third in
2009. The 2010 Prius has an estimated U.S. Environmental Protection Agency
combined fuel economy cycle of 50 miles per US gallon (4.7 L/100 km; 60
mpg-imp). [9]
The Audi Duo III was introduced in 1997, based on
the Audi B5 A4 Avant, and was the only Duo to ever make it into series
production. The Duo III used the 1.9 litre Turbocharged Direct Injection (TDI)
diesel engine, which was coupled with a 21 kilowatts (29 PS; 28 bhp) electric
motor. Unfortunately, due to low demand for this hybrid because of its high
price, only about sixty Audi Duos were produced. Until the release of the Audi
Q7 Hybrid in 2008, the Duo was the only European hybrid ever put into production.
The Honda Civic Hybrid was introduced in February 2002 as a 2003 model, based
on the seventh generation Civic. The 2003 Civic Hybrid appears identical to the
non-hybrid version, but delivers 50 miles per US gallon (4.7 L/100 km; 60
mpg-imp), a 40 percent increase compared to a conventional Civic LX sedan.
Along with the conventional Civic, it received styling update for 2004. The
redesigned 2004 Toyota Prius (second generation) improved passenger room, cargo
area, and power output, while increasing energy efficiency and reducing
emissions. The Honda Insight first generation stopped being produced after 2006
and has a devoted base of owners. A second generation Insight was launched in
2010. In 2004, Honda also released a hybrid version of the Accord but discontinued
it in 2007 citing disappointing sales. [10]
The Ford Escape Hybrid, the first hybrid electric
sport utility vehicle (SUV) was released in 2005. Toyota and Ford entered into
a licensing agreement in March 2004 allowing Ford to use 20 patents[citation
needed] from Toyota related to hybrid technology, although Ford's engine was
independently designed and built.[citation needed] In exchange for the hybrid
licenses, Ford licensed patents involving their European diesel engines to
Toyota.[citation needed] Toyota announced calendar year 2005 hybrid electric
versions of the Toyota Highlander Hybrid and Lexus RX 400h with 4WD-i, which
uses a rear electric motor to power the rear wheels negating the need for a
transfer case. [10]
In 2006, General Motors Saturn Division began to
market a mild parallel hybrid in the form of the 2007 Saturn Vue Green Line
which utilized GM's Belted Alternator/Starter (BAS Hybrid) System combined with
a 2.4 litre L4 engine and a FWD automatic transmission. The same hybrid power-strain
was also used to power the 2008 Saturn Aura Green line and Malibu Hybrid
models. As of December 2009, only the BAS equipped Malibu is still in (limited)
production. [10]
In 2007, Lexus released a hybrid electric version of
their GS sport sedan, the GS 450h, with a power output of 335 bhp. The 2007
Camry Hybrid became available in Summer 2006 in the United States and Canada.
Nissan launched the Altima Hybrid with technology licensed by Toyota in
2007.
Commencing in the fall of 2007 General Motors began
to market their 2008 TwoMode Hybrid models of their GMT900 based Chevrolet
Tahoe and GMC Yukon SUVs, closely followed by the 2009 Cadillac Escalade Hybrid
version. For the 2009 model year, General Motors released the same technology
in their half-ton pickup truck models, the 2009 Chevrolet Silverado and GMC
Sierra Two-Mode Hybrid models.
The Ford Fusion Hybrid officially debuted at the
Greater Los Angeles Auto Show in November 2008, and was launched to the U.S.
market in March 2009, together with the second generation Honda Insight and the
Mercury Milan Hybrid.
Fig. 11.1 1997 Toyota Prius (first generation)
Fig. 11.2 2000 Honda Insight (first generation)
Future works
There are several subjects concerning control of
hybrid electric vehicles that are not dealt with. Some interesting questions to
investigate are suggested below.
The control strategy optimizing for ICE efficiency,
does not consider the overall efficiency at all. An interesting study would
therefore be to develop an algorithm that optimizes for the overall efficiency.
The hybrid vehicle in the simulation model is run on
diesel fuel, but it would be interesting to study the efficiency and emission
formation with bio fuels, like Ethanol or DME, when used in a hybrid vehicle.
Cylinder deactivation is used in this study to adapt
the ICE power for low power requirements. Another solution could be using a
small ICE that is strongly overcharged to handle the highest power
requirements. The engine could in that case be provided with an electric turbo
charger.
If the unit that distributes the demanded power to
the electric machine(s) and the ICE would be able to predict the driving cycle,
new possibilities open up. This would influence the usage of the batteries,
i.e. there is a potential to reduce losses. One solution is to use a GPS that
can predict the route. Another possibility is to use a control algorithm that
by means of the last time period (µs/ms/s/min) can calculate a forecast of the
demanded power.
This study presents a number of different parameters
but only a limited number of possible alternatives and simulations. There are
programs available which purpose is to find an optimized solution in a system containing
a number of adjustable parameters. Such a procedure might be interesting to try
out on this simulation model. All parameters investigated in the previous study
(Jonasson, 2002) should also be included in such optimization.
When implementing cylinder deactivation, the
necessity of a large battery decreases since the range of load points including
high ICE efficiency increases. Therefore, it would be interesting to carry out
further investigations where the battery size is decreased.
A particular type of electric hybrid vehicles is
called plug in-hybrids. The idea is to mainly utilize the electric machine(s)
in these vehicles and mainly charge the battery from the grid. The ICE is more
or less utilized as a range extender. An advantage with this, which would be
interesting to investigate further, is the environmental potential it
implies.
The optimization has not been carried out with
intention to choose the best temperature condition, regarding SCR. This can of
course be tried out in further works.
The received results points at the need of a control
algorithm adjusted for hybrid implementation. It would therefore be valuable to
perform measurements on the engine when the different control algorithms are
implemented and adjusted. One questions to answer is, for example, what happens
to the engine while large amount of EGR is used? How would the hybrid vehicle
be affected by changes of the injection angle and other means of combustion
control?
In the model it has been assumed that the included filter
for PM is sufficient. It would be interesting to study this assumption closer,
and to investigate the influence on the filter performance with higher EGR
rates.
CONCLUSION
Means a hybrid vehicle is a vehicle that uses two or
more distinct power sources to move the vehicle. The term most commonly refers
to hybrid electric vehicles (HEVs), which combine an internal combustion engine
and one or more electric motors.
Modern HEVs make use of efficiency-improving
technologies such as regenerative braking, which converts the vehicle's kinetic
energy into electric energy to charge the battery, rather than wasting it as
heat energy as conventional brakes do. Some varieties of HEVs use their
internal combustion engine to generate electricity by spinning an electrical
generator (this combination is known as a motor-generator), to either recharge
their batteries or to directly power the electric drive motors. Many HEVs
reduce idle emissions by shutting down the ICE at idle and restarting it when
needed; this is known as a start-stop system. A hybrid-electric produces less
emissions from its ICE than a comparably-sized gasoline car, since an HEV's
gasoline engine is usually smaller than a comparably-sized pure
gasoline-burning vehicle (natural gas and propane fuels produce lower
emissions) and if not used to directly drive the car, can be geared to run at
maximum efficiency, further improving fuel economy.
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