hybrid electric truck document

Hybrid Electric Truck
Department of EEE, ACEM Page no: 1
1. INTRODUCTION
The traditional internal combustion engine made economic sense when oil was cheap and
plentiful and the effects of burning fossil fuels and pollution were not understood. Although
electric vehicles were popular at the start of the 20th century, they declined given their low top
speed, and the discovery of large oil reserves. One hundred years later, oil now accounts for
about 95 per cent of the global transportation sector fuel and 13 percent of global greenhouse gas
emissions.
The environmental damage from the internal combustion engine is further compounded by
the problem of air pollution. As well as carbon dioxide emissions, cars also produce dangerous
chemicals such as nitrogen oxides (NOx), Sulphur oxide (SOX) and carbon monoxide emissions.
While the industry has been able to produce technologies to try to limit these dangerous
chemicals, transport using fossil fuels cannot completely eliminate these emissions.
The problem of lost energy, as well as the need to reduce carbon emissions and reduce
dangerous pollutants, has spawned the industry to attempt to meet these challenges, whilst
sticking to the traditional petrol and diesel run engine. Indeed a lot of these technologies,
whether it be turbo chargers to improve fuel efficiency, catalytic converters that can remove
dangerous gases or drivetrain technologies that address problems of wasted energy. These
technologies have directly contributed to huge improvements being made in the last 20 years,
however, over the next 5 to 10 years the industry needs to accelerate this improvement.
The key issues for widespread EV adoption are the lack of range and the lack of refueling
infrastructure. Most EVs have a range of about 100 miles, with some as low as 48 before they
need recharging. When you do recharge, they inevitably take much longer to charge than it does
to fill your car with fuel. This presents an important impediment to the widespread adoption of
electric vehicles, if consumers have to sacrifice convenience. Until widespread adoption occurs,
companies are unwilling to invest in infrastructure to ensure it's easier to recharge your car, and
until you can conveniently refuel, consumers are unlikely to adopt EVs on a wide scale.

2. HET TechnicalConsiderations
In general, HEVs outperform conventional vehicles in terms of fuel consumption and
pollutant emissions. However, the degree of HEV performance and cost savings achieved largely
depend on its application (including the types of trips), the level of available technical service
and maintenance, fuel price, and the availability of optimal fuel quality.
2.1 Basics of HEV technology
A conventional vehicle has a mechanical drive train that includes the fuel tank, the
combustion engine, the gear box, and the transmission to the wheels. A HEV has two drive trains
- one mechanical and one electric. The electric drive train includes a battery, an electric motor,
and power electronics for control. In principle, these two drive trains can be connected with each
other, sharing some components such as the transmission and gear box. The ‘hybrid’ denotation
refers to the fact that both electricity and conventional fuel can be used. Current hybrid models
all use gear boxes, but in the future a single one-gear transmission might be a reality for series
hybrid configurations as the electric drive train can handle a wide variety of speeds and loads
without losing efficiency. This is already used in Brazilian HEV buses.
2.2 Plug-in hybrid electric vehicles
By enabling, enlarging the battery pack and recharging it with energy from a conventional
wall plug, vehicle fuel consumption will be reduced dramatically as it is partly exchanged with
the consumption of electricity. As a result, the fuel reduction depends strongly on the distance
driven after every recharge and on the capacity of the batteries installed. At the time of writing,
PHEVs are still in the testing phase. The announced PHEV prototypes will have a battery-only
range between30-60 km. For many users this will be sufficient for a large share of the daily
distance traveled.

2.3 Technical Constraints
In order to drive HEVs in developing countries, some basic technical and service
requirements must be met, e.g. requirements for fuel and battery quality and technical support
infrastructure.
2.4 Fuel quality requirements.
Both conventional vehicles and HEVs with catalytic converter scan be used with high
Sulphur petrol fuel as long as the fuel is unleaded. However, emission reduction technologies
have a better efficiency with low and ultra-low Sulphur fuels. The only technical requirement is
unleaded fuel in order to ensure proper function of the catalytic converter.
This is very promising for the introduction of HEVs to developing countries, as unleaded
petrol fuel is available in most countries. Since fuel requirements set by car importers and car
manufacturers can differ from region to region, one should check the requirements set by them to
ensure the vehicle warrantee is maintained. If modern emission control technologies are used,
e.g. NOx traps or Diesel Oxidation Catalyst, low Sulphur fuels (500 ppm or less) will be
required.
3. Main components of HETs
In general a hybrid electric truck comprises of both mechanical and electrical components
the main components are explained briefly and other are excluded for simplicity.
Electrical components
1. Lithium-ion Batteries,
2. 3-Phase power converter,
3. Control and monitoring,
4. 3-Phase induction motor &
5. Range extender (3- Phase PM synchronous generator).

Mechanical components
1. Gasoline engine,
2. Automatic transmission system &
3. Drive wheels.
Fig.3.1 Complete assembly of electric truck.
3.1 Lithium-ion Batteries
A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions
move from the negative electrode to the positive electrode during discharge and back when
charging. Li-ion batteries use an intercalated lithium compound as one electrode material,
compared to the metallic lithium used in a non-rechargeable lithium battery. The electrolyte,
which allows for ionic movement, and the two electrodes are the constituent components of a
lithium-ion battery cell.

Chemistry, performance, cost and safety characteristics vary across LIB types. Handheld
electronics mostly use LIBs based on lithium cobalt oxide (LiCoO2), which offers high energy
density, but presents safety risks, especially when damaged. Lithiumironphosphate (LiFePO4),
lithium ion manganese oxide battery (LiMn2O4, Li2MnO3, or LMO) and lithium nickel
manganese cobalt oxide (LiNiMnCoO2 or NMC) offer lower energy density, but longer lives and
inherent safety. Such batteries are widely used for electric tools, medical equipment and other
roles. NMC in particular is a leading contender for automotive applications. Lithium nickel
cobalt aluminum oxide (LiNiCoAlO2 or NCA) and lithium titanate (Li4Ti5O12 or LTO) are
specialty designs aimed at particular niche roles. The newer lithium–sulfur batteries promise the
highest performance-to-weight ratio.
3.2 Control and monitoring.
The control and monitoring of hybrid electric trucks is very important to obtain better
performance of the vehicle and also for continous monitoring of aspects such as i) Battery level,
ii)Fuel level, iii) Speed, iv)Distance travelled v) Position of gear & vi) Power generated.
The following figures show the controlling and monitoring display of HET.
Fig.3.2 Controlling system of an electric vehicle.

Fig.3.3 Display of monitoring system
3.3 3 - Phase power converter
A 3-phase power converter is employed to perform operations such as
a) Charging of batteries (Rectifier).
A rectifier is an electrical device that converts alternating current (AC), which periodically
reverses direction, to direct current (DC), which flows in only one direction. The process is
known as rectification. Physically, rectifiers take a number of forms, including vacuum tube
diodes, mercury-arc valves, copper and selenium oxide rectifiers, semiconductor diodes, silicon-
controlled rectifiers and other silicon-based semiconductor switches.
b) Converts DC to AC operation(inverter).
A power inverter, or inverter, is an electronic device or circuitry that changes direct
current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and
overall power handling depend on the design of the specific device or circuitry. The inverter does
not produce any power; the power is provided by the DC source.

A power inverter can be entirely electronic or may be a combination of mechanical
effects (such as a rotary apparatus) and electronic circuitry. Static inverters do not use moving
parts in the conversion process.
3.4 3-Phase induction motor.
An induction motor is an AC electric motor in which the electric current in the rotor
needed to produce torque is obtained by electromagnetic induction from the magnetic field of the
stator winding. An induction motor can therefore be made without electrical connections to the
rotor. An induction motor's rotor can be either wound type or squirrel-cage type.
Three-phase squirrel-cage induction motors are widely used in industrial drives because
they are rugged, reliable and economical. In Hybrid Electric Trucks (HETs)a high power
induction motor is employed for the drive system in which it is fed by both battery and generated
electrical power simultaneously.
3.5 Range extender (3- Phase PM synchronous generator).
A permanent magnet synchronous generator is a generator where the excitation field is
provided by a permanent magnet instead of a coil. The term synchronous refers here to the fact
that the rotor and magnetic field rotate with the same speed, because the magnetic field is
generated through a shaft mounted permanent magnet mechanism and current is induced into the
stationary armature.
Fig.3.4 Basic construction of PM synchronous generator.

Fig.3.5 Range extender
3.6 Gasoline engine
A gas engine is an internal combustion engine which runs on a gas fuel, such as coal gas,
producer gas, biogas, landfill gas or natural gas. In the UK, the term is unambiguous. In the US,
due to the widespread use of "gas" as an abbreviation for gasoline, such an engine might also be
called a gaseous-fueled engine or natural gas engine or spark ignited.
Generally the term gas engine refers to a heavy-duty industrial engine capable of running
continuously at full load for periods approaching a high fraction of 8,760 hours per year, unlike a
gasoline automobile engine, which is lightweight, high-revving and typically runs for no more
than 4,000 hours in its entire life. Typical power ranges from 10 kW (13 hp) to 4,000 kW
(5,364 hp).
3.7 Automatic Transmission system.
An automatic transmission, also called auto, self-shifting transmission, n-speed automatic
(where n is its number of forward gear ratios), or AT, is a type of motor vehicle transmission that

can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift
gears manually. Like other transmission systems on vehicles, it allows an internal combustion
engine, best suited to run at a relatively high rotational speed, to provide a range of speed and
torque outputs necessary for vehicular travel. The number of forward gear ratios is often
expressed for manual transmissions as well (e.g., 6-speed manual).
The most popular form found in automobiles is the hydraulic automatic transmission.
Similar but larger devices are also used for heavy-duty commercial and industrial vehicles and
equipment. This system uses a fluid coupling in place of a friction clutch, and accomplishes gear
changes by hydraulically locking and unlocking a system of planetary gears. These systems have
a defined set of gear ranges, often with a parking pawl that locks the output shaft of the
transmission to keep the vehicle from rolling either forward or backward. Some machines with
limited speed ranges or fixed engine speeds, such as some forklifts and lawn mowers, only use a
torque converter to provide a variable gearing of the engine to the wheels.
Fig.3.6 Automatic transmission system

3.8 Drive wheels.
A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into
tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers
enough torque to the wheel to overcome stationary forces, resulting in the vehicle moving
forwards or backwards. A steering wheel is a wheel that turns to change the direction of a
vehicle. A trailer wheel is one that is neither a drive wheel, nor a steer wheel. Front-wheel drive
vehicles typically have the rear wheels as trailer wheels.
This configuration allows all four road wheels to receive torque from the power plant
simultaneously. It is often used in rally racing on mostly paved roads. Four-wheel drive is
common in off-road vehicles because powering all four wheels provides better control on loose
and slippery surfaces. Four-wheel drive manufacturers have different systems such as "High
Range 4WD" and "Low Range 4WD". These systems may provide added features such as
varying of torque distribution between axles or varying gear ratios.
Common terms for this configuration include four-wheel drive, 4WD, 4x4 (pronounced "four-
by-four"), and all-wheel drive (AWD).
4. Types of power trains.
There are two main power train systems for HETs they are
i) Series power train system &
ii) Parallel power train system.
4.1 Series power train system.
We can see that the series HET is composed of ICE, generator, power converter, motor,
and battery. There is no mechanical connection between ICE and transmission, thus ICE can
operate at maximum efficient point by regulating the output power of battery to satisfy the
required power of vehicle.

Fig.4.1 Series power train system
4.2 Parallel power train system.
From Figure we can see that the parallel HEV allows both the electric motor and ICE to
deliver power in parallel to drive the vehicle, that is, ICE and motor can drive, respectively, or
together. Different from the series HEV, there is mechanical connection between ICE and
transmission, and thus the ICE’s rotational speed depends on the driving cycle, so the ICE can
operate based on optimal operating line by regulating the output power of battery.

Fig.4.2 Parallel power train system.
5. Charging of batteries.
The charging (Recharge) of batteries in the vehicle is carried out by the following
ways.
i) Standard 230V, 50HZ AC supply,
ii) In charging stations,
iii) During range extension &
iv) During regenerative braking.
5.1 Standard 230V, 50HZ AC supply.
The vehicle is connected to the main power grid via household socket-outlets. Charging
is done via a single-phase or three-phase network and installation of an earthing cable. A
protection device is built into the cable. This solution is more expensive than Mode 1 due to the
specificity of the cable. A control and protection function is also installed permanently in the
installation. This is the only charging mode that meets the applicable standards regulating

electrical installations. It also allows load shedding so that electrical household appliances can be
operated during vehicle charging or on the contrary optimises the electric vehicle charging time.
5.2 In charging stations.
An electric vehicle charging station, also called EV charging station, electric recharging
point, charging point, charge point and EVSE (electric vehicle supply equipment), is an element
in an infrastructure that supplies electric energy for the recharging of electric vehicles, such as
plug-in electric vehicles, including electric cars, neighborhood electric vehicles and plug-in
hybrid. Many charging stations are on-street facilities provided by electric utility companies or
located at retail shopping centers and operated by many private companies. These charging
stations provide one or a range of heavy duty or special connectors that conform to the variety of
electric charging connector standards.
Fig.5.1 Charging station
5.3 During range extension.
The charging of batteries in the vehicle is also done by range extender while the batteries
having low voltage. This facility is available only with HEVs ordinary electric vehicles does not
contain any range extender so the charging can be done by range extender.

5.4 Regenerative Braking.
The one more advantage of electric vehicles id regenerative braking by this also the
batteries can be charge and also better braking compared to mechanical breaking.
when used in reverse function as generators, convert mechanical energy into electrical
energy. Vehicles propelled by electric motors use them as generators when using regenerative
braking, braking by transferring mechanical energy from the wheels to an electrical load.
6. How to drive?
Driving of HETs is little different from ordinary mechanical vehicles because it does not
contain Clutch Mechanism. This helps the driver to a better driving experience and control on
vehicle.
This does not change gears automatically, but rather facilitates manual gear changes by
dispensing with the need to press a clutch pedal at the same time as changing gears. It uses
electronic sensors, pneumatics, processors and actuators to execute gear shifts on input from the
driver or by a computer. This removes the need for a clutch pedal which the driver otherwise
needs to depress before making a gear change, since the clutch itself is actuated by electronic
equipment which can synchronise the timing and torque required to make quick, smooth gear
shifts. The system was designed by automobile manufacturers to provide a better driving
experience through fast overtaking maneuvers on highways.
The HET offers two different modes of operation i) Full electric mode and ii) Range
extension mode.
6.1 Full electric mode.
In this mode of operation the truck runs completely with electrical energy stored in
batteries which are charged previously. During this operation the engine of truck is kept in ideal
position.
6.2 Range extension.
In this mode the engine must be started and the power is generated by means of range
extender which is nothing but a synchronous generator coupled to gasoline engine (refer section
3.5) the range extender will supplies power to 3-phase induction motor and also recharge the

batteries simultaneously this helps the truck to extended the range and perform in an better
efficient way to increases mailage (upto 100mpg).
7. Powerexport
One of the main feature of this type of truck is power export which means capable of
delivering on board power for non traction applications such as welding, drilling etc…
It can also capable of supplying power to home during outage simply saying it will acts as a
Diesel generator (DG) the main difference between the DG and the truck is cost per unit
generated i.e. the cost per unit generated by DG is 9to10 rupees where as the cost is reduced to
less than 2.5 rupees by using this type of hybrid vehicle.
Fig.7.1 2 X 230V, 50 HZ AC supply ports.

Fig. 7.2 Power feeding a home during outage.
The above two figures shows the power export facility of HET in which contains output
power ports shown in fig 7.1 and the truck feeding the power during outage shown in fig 7.2.
8. Regenerative braking.
A regenerative brake is an energy recovery mechanism which slows a vehicle or object
by converting its kinetic energy into a form which can be either used immediately or stored until
needed. This contrasts with conventional braking systems, where the excess kinetic energy is
converted to unwanted and wasted heat by friction in the brakes. In addition to improving the
overall efficiency of the vehicle, regeneration can greatly extend the life of the braking system as
its parts do not wear as quickly. When electric motors used in reverse function as generators,
convert mechanical energy into electrical energy. Vehicles propelled by electric motors use them
as generators when using regenerative braking, braking by transferring mechanical energy from
the wheels to an electrical load.

Fig.8.1 Regenerative braking applied to an electric car.

9. Advantages and disadvantages.
9.1 Advantages:
 Better fuel economy (>100mpg).
 Unlimited range.
 Lower operating cost.
 Easily rechargeable at home.
 Lower maintenance.
 Nearly zero emissions.
9.2 disadvantages:
 20 to 30 % increased weight.
 High initial cost.
 Availability of service centers.
 Lack of public awareness.

10. Conclusion.
HEV technology for both light and heavy duty applications is commercially available
today and demonstrates substantial reductions in tail-pipe emissions and fuel consumption, even
when compared to other available low emission technologies. HEVs are particularly effective for
urban travel, significantly lowering pollutant emissions and providing cost-effective CO2
reductions in personal mobility. Encouraging hybridization of vehicle fleets through enabling
policies and incentive structures can serve to lower both conventional and CO2 emission, thus
improving public health, energy security, and reducing fuel costs. Continuing innovation in
hybrid technology and a growing demand for cleaner vehicles will mean that costs are likely to
fall.
There is a future scope for Solar powered HETs in which solar panels are employed for
range extension and also there is a scope for Hybrid Electric Tractors for agriculture purpose
which will became solution for fuel deficiency future.

BIBLIOGRAPHY
1. Matt Lake (2001-11-08). "How it works; A Tale of 2 Engines: How Hybrid Cars Tame
Emissions". The New York Times. Retrieved 2010-03-22.
2. Elizabeth Lowery (2007-07-01). "Energy diversity as a business imperative". The
Futurist. Retrieved 2010-03-21.
3. Dale Buss and Michelle Krebs (2008-06-03). "Big Three, Big Vehicles Taken to the
Watershed in May". Edmunds Auto Observer. Retrieved 2010-03-21.
4. Cobb, Jeff (2016-06-06). "Americans Buy Their Four-Millionth Hybrid Car".
HybridCars.com. Retrieved 2016-06-06.
5. Dan Rutherford (2014-04-04). "Hybrids breakthrough in the Japan auto market".
International Council on Clean Transportation (ICCT). Retrieved 2015-01-25.
6. International Council on Clean Transportation (ICCT) (2016). "European Vehicle Market
Statistics - Pocketbook 2015/16" (PDF). ICCT. Retrieved 2016-06-17. See Figure 4-2
and 4-6, pp 41-44. See also tables in pp. 81-107 for HEV market by country from 2001 to
2014.
7. K. Rajashekara, “History of electric vehicles in General Motors,” IEEE Trans. Ind.
Applicat., vol. 30, no. 4, pp. 897–904, July 1994.
8. C. C. Chan, “The state of the art electric, hybrid and fuel cell vehicles,” Proc. IEEE, vol.
95, no. 4, pp. 704–718, Apr. 2007.
9. WWW.Google.co.in.
10. Wikipedia.

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