Prototyping an Exhaust Driven Turbogenerator for Automotive Applications

Prototyping an Exhaust Driven
Turbogenerator for Automotive
Applications
Presented By
Akshay Bhivshet, Khushboo Gupta, Sarth Jauhari and Sohan Nair
To The Faculty
Of
Mumbai University
For The Degree
Bachelor of Engineering In
Automobile Engineering
November, 2014

Project Report Approval for B.E.
This project report entitled Prototyping an Exhaust Driven Turbogenerator for
Automotive Applications by Akshay Bhivshet (AE762), Khushboo Gupta (AE732),
Sarth Jauhari (AE757) and Sohan Nair (AE729) is approved for the degree of Bachelor
of Engineering in Automobile Engineering
Examiner
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Supervisors
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Chairman
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Date:
Place:

Declaration
I declare that this written submission represents my ideas in my own words and where
others' ideas or words have been included, I have adequately cited and referenced the
original sources. I also declare that I have adhered to all principles of academic honesty
and integrity and have not misrepresented or fabricated or falsified any
idea/data/fact/source in my submission. I understand that any violation of the above will
be cause for disciplinary action by the Institute and can also evoke penal action from the
sources which have thus not been properly cited or from whom proper permission has not
been taken when needed.
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(Signature)
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Date:

1. Acknowledgement
We remain immensely obliged to Prof. Rashed Ali for providing us with the
knowledge of this topic, and for his invaluable support in garnering resources for us either
by the way of information or computers; also his guidance and supervision which made
this happen. We are also greatly thankful to our alma mater, Pillai’s Information of
Technology where this project was undertaken and realized.
We would like to thank our guides in Bhatti Motors (TATA) Pvt. Ltd. for their
guidance during the training period.
We thank our workshop professors Prof. Anil, for helping us realize the physical model
by guiding us through the difficulties and hurdles we faced during construction.
We would also like to thank our friends Kishore Gunjalkar and Manoj Sharma for helping
us out at various stages of the project.
We would like to say that it has been indeed a gratifying and learning experience
while working on this Project.

2. Abstract
The need for more efficient and less polluting cars has been a major driving force is many
fields of automotive engineering. Even in the modern day of high technological
sophistication about 30-40% of the work done by engine is wasted in the form of hot
exhaust gases. There seems to be great potential in harnessing this substantial source of
energy.
Our experimental model of a turbo-generator aims to seek a possibility to work
towards these goals especially for passenger cars and commercial vehicles. We also hope
that similar devices can be incorporated in hybrid vehicles and will not be exclusive to
conventional systems.
The turbine driven turbocharger works on the Rankine cycle, in which the hot
exhaust gases hit radially on the turbine blades and expand. The expansion of gases and
their cooling causes the turbine to rotate. In a conventional turbocharger, this is used to
run an air compressor which sucks in additional air to be used with the inlet air fuel
mixture of the engine. However, in our model we will try to use the rotational motion of
the turbine to run a D.C. Generator to produce electricity, hoping to eliminate the need for
the alternator which uses power from engine, reducing its efficiency. The primary benefit
from this concept would be to utilize the waste energy of the engine. Apart from this,
we’re hoping it will lead to less harmful emissions
The following report is a detailed study of the concept as well as the procedure and
methodology followed by us to achieve the working model of the imagined concept.
From the conception of the idea to its evolution through research and study to the final
materialization of the concept as the prototype has been detailed in the report.

2.1 Report Layout
There are various Energy Recovery Systems that have been developed and are currently
under active development by various manufacturers and research organizations. We shall
take a look at just some of these developments in the Chapter 2 of this report. The third
Chapter will deal with the various difficulties and obstacles that are faced in wider use of
this technology and incorporation in passenger and commercial vehicles. The procedure
followed by us to develop a prototype of the technology and the approach we took will be
detailed in the Chapter 4. The fifth chapter would shed some light on alternative
approaches to the use and implementation of similar technologies. The sixth and the final
chapter will deal with what we believe can be the future scope for this technology, who
and what can benefit from it and how it could improve automotive technologies

Contents
Project Report Approval for B.E..................................................................................................................................1
Declaration........................................................................................................................................................................3
Abstract ..............................................................................................................................................................................5
1. INTRODUCTION ................................................................................................................................................9
1.1 Background...................................................................................................................................................9
1.2 Methodology ................................................................................................................................................11
1.3 Report Layout...............................................................................................................................................6
2. LITERATURE SURVEY......................................................................................................................................12
2.1 Introduction ................................................................................................................................................12
2.2 Methodology of Review.......................................................................................................................13
2.3 Overview of Studies ..............................................................................................................................13
2.3.1 Active Application........................................Error! Bookmark not defined.
2.3.2 Concepts and Prototypes.............................................................................. 31
2.3.3 Research and Studies ....................................Error! Bookmark not defined.
3. PROBLEM DEFINITION AND REQUIREMENT.............................Error! Bookmark not defined.
4. MODELLING AND FABRICATION ..............................................................................................................17
4.1 Engine.......................................................................................................................................................17
4.2 Frame........................................................................................................................................................18
4.2.1 Material Selection........................................................................................ 18
4.2.2 Plan of Construction .................................................................................... 18
4.3 Turbocharger .........................................................................................................................................20
4.3.1 Basics [24].................................................................................................... 20
4.3.2 Construction and Working [25].................................................................... 20
4.3.3 Technical Specifications ...............................Error! Bookmark not defined.
4.4 DC Generator..........................................................................................................................................22
4.4.1 Basics [26].................................................................................................... 22
4.4.2 Construction................................................................................................. 22
4.5 Working ..................................................................................................................................................24
4.6 Assembly..................................................................................................................................................25
5. ALTERNATIVE APPROACHES ............................................................Error! Bookmark not defined.
6. FUTURE SCOPE..................................................................................................................................................35

6.1 Turbo Air Conditioning.......................................................................................................................35
6.2 TURBO ALTERNATOR ......................................................................................................................39
6.3 Turbocompounding....................................................................Error! Bookmark not defined.
7. REFERENCES .......................................................................................................................................................41

3. INTRODUCTION
3.1 Background
The modern car has come a long way from its early days, setting new records and
milestones along the way. The driving force of the car, the engine too has evolved
immensely in many respects. And yet after decades of development, there seems some
major lacking in the way that the Internal Combustion engines work. Only about 25% to
30% of the total energy produced by a typical I.C. Engine is utilized for desirable
purposes. The remaining 75% to 80% of the energy generated is completely wasted in the
form of sound, vibration and heat losses. In the modern world where there is a large
demand for greater fuel efficiency, emission norms and sustainability, it is obvious that
the cars either need a new way to generate power or drastically improve the existing
Internal Combustion technology.
About 40% of the work done by the Internal Combustion engine is wasted in the
form of hot exhaust gases. If only some part of this waste can be harnessed for some kind
of useful work, it would significantly increase the overall efficiency of the engine. This
report deals with one such method to use the waste by-products of the engine for useful
work.
Using the exhaust of the engine is a new field of development in automobile
research to squeeze out every Watt of energy from the combustion engines. There is
active research and new developments in the field and is also of great interest for
automobile manufacturers in light of ever stringent emission and efficiency norms. The
technology has recently been made popular by the Formula 1 (and also Le Mans
Prototypes) regulations of 2014 where a similar turbine driven system is used to generate
electricity from the waste exhaust gases. This electricity is however used for bursts of
greater speed and torque for overtaking purposes to make the sport more exciting. More
modest uses of such technologies seem viable for passenger cars and even other vehicles
not excluding aircrafts, marine vehicles and railroad locomotives.

Figure 3-1: Sankey diagram of power flow in a combustion engine

3.2 Methodology
The conventional automobiles that run on Internal Combustion engines have no way to
utilize the hot exhaust gases except in the case of turbo charged engines that use the hot
exhaust to compress the intake air for the engine, thus improving engine output. Our
concept makes use of technologies that are already existent and easy to incorporate.
Using a turbine from the turbocharger we attempt to draw energy that can be used
in various ways for various purposes. In our prototype we have used an alternator to be
powered from the turbocharger electricity from which can be utilized in various
applications of a car. Conventionally this was done by extracting some amount of energy
directly from the engine using a belt drive thus reducing the efficiency of the engine. With
the use of proposed technology, the energy required for the automotive alternator need to
be drawn from the engine’s output but instead can be drawn from the waste exhaust of the
engine.
.

4. LITERATURE SURVEY
4.1 Introduction
Before we began the construction of our model, we had to take a look and quite many
studies being done on this subject. Being a relatively new area of study, it is a field of
active development and much research is still under way. The early studies are very
promising, but the results are not yet definitive for all the areas in which it can be applied.
Automobile manufacturers have taken keen interest in such technologies due various
reasons like stringent emission norms, increasing fuel prices, concern for the environment
and demand from the consumers for fuel efficient cars. Manufacturers like BMW, Renault
all have underdevelopment various technologies similar and very different to our own
concept for the purpose of making cars more fuel efficient.
Even though this technology has seen implementation recently in the form of
motorsports like Formula 1 and Le Mans, it is still not obvious that the same would
substantially benefit the road cars. The sports cars run at very high speeds for long periods
on the track thus, making sure a significant amount of hot exhaust is generated to run the
turbines.
Similar technologies like Turbosteamers, Turbocompounds and other ways of exhaust
heat utilizations are under active developments
Apart from road cars, there also seems scope for this technology in marine, aviation
and even industrial applications. We will try to take a glimpse at these applications as
well. It will give us an idea of what kind of

4.2 Methodology of Review
The research studies chosen for this review depending on various criteria. As the
main objective for the review was to give us a better understanding of the technology
before we began construction, we took a look at not only the already existing applications,
but also various other prototype models and theoretical models of the same.
This process made us familiar with the difficulties and challenges that might lay
ahead in the building of our prototype and gave us a fair preparation for difficulties that
we faced.
Using online resources like Google Scholar, made it easier to access many studies in
this field. Apart from Google Scholar, various journals like SAE International Journals,
have immensely aided our research on the topic.
The keywords used in searching for these databases included exhaust, heat, energy,
recovery, turbogenerator, turboalternator, TERS, waste heat etc.
4.3 Overview of Studies
There is active research on this subject due to various reasons stated earlier. It has
been a subject of great interest for students and academics alike in recent years. We will
take a look at some of these studies in this section.
An important research undertaken at Queen’s University, Belfast in this technology has
been of great value. The study carried out by three post graduate students in collaboration
with Wrightbus Ltd, Ricardo Ltd and Revolve Technologies Ltd. [1] [2]
The objective of the project was to reduce the fuel consumption on a Wrightbus’
hybrid bus using turbo-compounding technology. Turbo-compounding is the process of
using a turbine to recover energy from exhaust gases. The energy thus recovered can be

utilized in three ways, by mechanically connecting to the crankshaft, or by electric or
hydraulic systems.
Figure 4-1: Turbocompunding Schematic Layouts
In mechanical turbocompounding and the turbogenerator, wasted hot gases are fed from
the turbocharger turbine to a second power turbine as shown in Figure 2-8.
Mechanical turbocompounding connects the power turbine directly to the engine’s
crankshaft via a system of gears as in Figure 2-8(a), while a turbogenerator connects the
power turbine to an electric generator (Figure 2-8(b)) which can be used to directly power
the electrical components of the engine via a battery.
The third method of turbocompounding, electric turbocharging, consists of a small
generator fitted on the shaft of the turbocharger (Figure 2-9)

Figure 4-2: Electric Turbocharger [3]
The particular study showed that for one load and speed point, an increase in system
power of 3.23% could be generated with a net BSFC saving of approximately 1.20%. The
maximum increase in total power produced from the device is 7.55% at full load.
A paper in 2004 by Sendyka and Soczwka concluded that an increase in power by 10-
11%, increase in torque by 11% and reduction in fuel consumption is possible by
turbocompounding. [4]
By using an axial power turbine on a 14.6L diesel engine, Tennant and Walsham were
able to get a reduction of Brake Specific Fuel Consumption (BSFC) by 4.7% for 50,000
mile running test in USA in 1989. The study also reported the application of this
technology giving Scania a 5% improvement in BSFC on a 6 cylinder 11L turbocharged
diesel engine. The design process for the turbocompound detailed in the paper claims to
reduce fuel consumption at all speeds. [5]

A study of turbocompund Cummins diesel engine by Brands, M., Werner, J., Hoehne,
J., and Kramer, S.in 1981 concluded that the incremental fuel consumption improvement
strictly due to the turbocompounding alone was estimated at 4.2% to 5.3% depending
upon the terrain or mission load factor. [6]
A 2006 paper by J. Bumby, S. Crossland, and J. Carter showed that a 7.5kW motor
generator within a standard turbocharger resulted in substantial reduction in smoke
generation and fuel economy increase by 6% in a 12 tonne city bus. [7]
But a 2009 study by Patterson, A., Tett, R., and McGuire, J. showed that mechanical
turbocompounding systems consume energy at low speeds and idling conditions are not
favourable for the requirement. [8]
A Feasibility study on Waste Heat Recovery in an I.C. Engine using Electro Turbo
Generation by S.N.Srinivasa Dhaya Prasad and N. Parameshwari in 2012 that the
useful work obtained from engine increased from 25% to only 25.025%, which is a small
quantity. The idea is at a present stage and with various improvements to the system and
better alternator design, such a system may be advantageous. [9]

5. MODELLING AND FABRICATION
This chapter describes the design and fabrication of the engine mounting frame and the
turbo-generator assembly.
5.1 Engine
Figure 5-1: Premier Padmini Engine
The engine used is a 4-cylinder, 4-Stroke inline SI engine belonging to a Premier Padmini
1997 model. Its specifications are as follows [10]:
Displacement 1089cc
Bore x Stroke [mm] 68 x 75
Cylinders Four
Maximum power 40bhp @ 4800rpm
Maximum torque 7.20kgm @ 3000rpm
Compression ratio 7:8:1

Transmission Manual, rear-wheeldrive
Number of gears Four
Maximum Speed 105 kph
Coolant Water
Aspiration Natural
5.2 Frame
In order to prevent the vibrations of the engine from reaching the ground, the engine was
required to be mounted on a frame.
5.2.1 Material Selection
The frame was made of structural steel due to the following factors [11]:
 High Compressive and Tensile Strength
 High Stiffness
 High Toughness
 Fire Resistant
 High Strength-to-Weight Ratio
 Readily Available
5.2.2 Plan of Construction
The design of the frame was similar to the frame of a table. Initially, a rectangular frame
was formed by welding together structural steel beams of 7cm X 7cm cross-section. Then,
four legs with a height of 25cm were attached at the four corners of the frame. The
supports for the engine and gearbox foundation were made after retrieving the foundation
mountings from the scrapped vehicle. Also, supports for the ignition coil, fuel tank and
radiator assembly were welded onto the frame.

Figure 5-2: Frame for Mounting
Support for Exhaust Pipe
Support for Ignition Coil
Support for Engine
Mounting Bracket
Support for Fuel Tank
Support for Radiator Assembly

5.3 Turbocharger
5.3.1 Basics [12]
Since the power a piston engine can produce is directly dependent upon the mass of air it
can ingest, the purpose of forced induction (turbo-supercharging and supercharging) is to
increase the inlet manifold pressure and density so as to make the cylinders ingest a
greater mass of air during each intake stroke.
5.3.2 Construction and Working [13]
A turbocharger is made up of two main sections: the turbine and the compressor.
5.3.2.1 Turbine
The turbine used is of single stage, radial flow type. It consists of the turbine wheel and
the turbine housing. Instead of being driven directly by the crankshaft. The turbine
extracts wasted kinetic and thermal energy from the high-temperature exhaust gas flow
and produces the power to drive the compressor, at the cost of a slight increase in
pumping losses. It is the job of the turbine housing to guide the exhaust gas into the
turbine wheel. The energy from the exhaust gas turns the turbine wheel, and the gas then
exits the turbine housing through an exhaust outlet area.
Figure 5-3

5.3.2.2 Compressor
The compressor used is of single stage, radial flow centrifugal type. It consists of two
parts: the compressor wheel and the compressor housing. Its mode of action is opposite
that of the turbine. The compressor wheel is attached to the turbine by a forged steel shaft,
and as the turbine turns the compressor wheel, the high-velocity spinning draws in air and
compresses it. The compressor housing then converts the high-velocity, low-pressure air
stream into a high-pressure, low-velocity air stream through a process called diffusion.
The compressed air is pushed into the engine, allowing the engine to burn more fuel to
produce more power.

5.4 DC Generator
5.4.1 Basics [14]
DC generators are basically electrical machines which convert mechanical energy to DC
electric current. This energy conversion is based on Faraday’s Law of Electromagnetic
Induction1.
5.4.2 Construction
Figure 5-4: Construction of a DC Generator
A simple 4-pole DC generator consists of the following main parts [15]:
1. Yoke
The outer frame of the DC generator is called the yoke. It is usually made up of
cast iron or steel. Its main function is to provide strength to the whole assembly. It
also carries the magnetic flux produced by the poles.
1 Faraday’s Law of Electromagnetic Induction states that when a conductormoves in a magnetic field it cuts
magnetic lines of force, due to which an emf is induced in the conductor.This emf will cause a current to
flow if the conductorcircuit is closed. The magnitude of this induced emf depends upon the rate of change
of flux (magnetic lines of force) linkage with the conductor.

2. Field System/ Field Magnet
The combination of the poles and pole shoes is known as the field magnet. This is
because it acts as a magnet when direct current is passed through the field coils.
a. Poles
Their main function is to support the field windings. They are joined to the
yoke with the help of screws or welding. The field windings are wound on
the poles and maybe connected in series or in parallel to the armature
windings. Lamination is done to the pole cores in some of the latest
generators so as preventing the problem of conduction through the pole
core [16].
b. Pole Shoes
These are extended parts of the pole. They fill the gap between the poel
and body. They serve four main purposes:
i. To prevent the field coils from slipping
ii. To uniformly spread the flux in a larger area of the air gap
iii. To enable the magnetic lines of flux to radially cross the air gap
3. Conductor System
a. Armature Core/Rotor
The armature core is a cylindrical structure built in laminations, which is
usually made of high grade silicon sheet steel. Laminated sheets are used in
order to minimize power loss due to eddy currents in the core of armature.
High grade silicon is used in order to minimize the current losses due to
hysteresis. Armature core has a main function to act as a support to
armature winding. The armature rotates through the magnetic while cutting
the magnetic lines of force. This produces an electric current in the
armature coil.

b. Armature winding/ Conductors
It acts as a conductor of electricity in general copper bars of required
dimension or when wire of same material of required cross section are
used.
4. Commutator
It is a pair of split rings which transfers current from the wire coil to the brushes. It
is mounted on the same shaft as the armature core. Its main function is to convert
the alternating current induced in the armature windings into unidirectional
current.
5. Brushes
These are used for transmission of current from the commutator to the external
load circuit. They are generally made of carbon and housed in a box-type brush
holder which is open at both ends.
5.5 Working
When the commutator is driven by a prime mover, the stator field is excited. This induces
a voltage in each armature conductor in accordance with Faraday’s Law of
Electromagnetic Induction. The direction of this voltage can be ascertained with the help

of Fleming’s Right Hand Rule2. For a loaded generator, the direction of the armature
current will be same as that of the induced voltage.
5.6 Assembly
First, the engine was salvaged from a wrecked Premier Padmini that was deteriorating on
the campus. This was done with the help of chisels, hammers, hacksaws and cutting
blades. The engine foundation was then attached to the engine. An engine mounting was
also obtained from the wrecked car which was used to simplify the angular measurements
required for the frame. Now, measurements were taken for the frame. The structural steel
beams were cut to the required dimensions and welded together. A support was also
provided for the gearbox mounting. The engine was then lifted manually and carefully
mounted on the frame. Once the engine was secured, various parts were replaced or
repaired. The radiator holes were plugged and then it was attached with the engine. A
1.5L fuel tank was found and connected to the carburettor. The exhaust pipe was cut and a
flange -which mated with the turbocharger – was welded to it. The turbocharger was
dismantled and its exhaust-side housing was attached to this flange. The turbine assembly
was also taken apart. It was found that the turbine shaft was too thin and weak. It could
easily bend under manual pressure. Hence, a DC generator having a shaft of similar cross-
section was obtained and both these shafts were coupled together using a sleeve. A
scrapped exhaust pipe belonging to a Maruti 800 was attached to the outlet side of the
turbocharger housing. It was trimmed to fit within the frame and a support was given.
2 Fleming's right hand rule (only generators)shows the direction of induced current when
a conductormoves in a magnetic field. When the right hand is held with the thumb, first finger and second
finger mutually perpendicular to each other,
 The thumb represents the direction of motion of the conductor.
 The first finger represents the direction of the field. (north to south)
 The second finger represents the direction of the induced or generated current

6. Active Applications
Here we take a look at the current use of the technology as it would give us the best
idea as to how this technology works in real world applications.
6.1 Formula 1 2014
The first and the most obvious choice was to look at the Formula 1 engines of
2014. The smaller than ever twin turbo 1.6L V6 engines are one of the most fuel efficient
engines that have been incorporated in Formula 1, without any compromise on
performance. The engines being produced by manufacturers such as Renault (Renault
Energy F1-2014, pictured above), Ferrari (Ferrari 059/3) and Mercedes (Mercedes
PU106A Hybrid).
Figure 6-1: Renault Energy F1-2014 Engine

This has been a great departure for FIA because they have been up to now using
naturally aspirated engines in the pinnacle of motorsports that is Formula-1, but with
pressure of making the motorsport industry more conscious of the environmental issues
and taking responsible actions for the cause, FIA made mandatory the use of smaller,
more efficient engines without any compromises on performance. A departure from 6 year
convention of using 2.4L V-8 naturally aspirated engines (from 2006 – 2013), in 2014, to
much discontent of the fans FIA switched to even smaller 1.6L
V-6 engine [17]. Since 2009, the power unit incorporated an element which indicated
FIA’s intentions of chasing greater efficiencies [18]. This unit was the KERS (Kinetic
Energy Recovery System) system, which in 2014 has been greatly improved and used
alongside another innovation called the TERS (Thermal Energy Recovery System),
together now known as simply ERS (Energy Recovery System). The TERS technology is
going to be the focus of our study here.
The turbochargers used in the 2014 V-6 engines aren’t just simple turbochargers,
but special units that develop electric energy while compressing the intake air for the
engine.
The TERS System consists of MGU-(H) unit attached to the turbo-compressor
which recovers the energy from the compressor that would have been wasted otherwise.
This recovery is done either when the driver is backing off the throttle (normally taken
care of by a wastegate) or when the pressure being produced supersedes the engines
requirements. The energy thus recovered is sent to the Energy Storage system, from where
it can be utilised by the MGUH itself to reduce the turbo-lag or by the MGU-K unit giving
additional power to the driver.

Figure 6-2: Parts of F1-2014 Engine [19]

6.2 World Endurance Championship
Another major motorsport event also under the FIA is the Le Mans Endurance
Championship. The new rules to the sport required teams to use 30% less fuel than
previous year. To this end, Le Mans Prototype Hybrids (LMP1-H) in 2014 saw energy
recovery features similar to the Formula 1 series. Kinetic Energy recovery and Heat
Energy recovery systems were developed and incorporated by the manufacturers.
Audi R18 e-tron Quattro running a 4L V6 turbodiesel engine, developed by Audi
for this competition included the thermal energy recovery system similar to Formula 1, in
which the turbocharger is connected to an MGU-H unit that converts the mechanical
energy from the hot exhausts into usable electrical energy. While accelerating from low
speeds, the energy will be utilized to reduce or eliminate turbo-lag of the innovative
electrical turbocharger, while at higher speeds it is used to provide extra speed to the front
axle. [20]
Figure 6-3: Audi R18 e-tron Quattro [21]
Later during the revealing of the competing cars, Audi announced that it had
abandoned the use of Heat Energy Recovery System. The reasons given by the German

manufacturer included reliability issues and gains in power not up to expectations. Other
factors included the adhering of weight limit regulations and weight balancing of the car.
[22] The Audi R18 e-trron Quattro of the Audi Sport Team Joest secured the 1st and 2nd
positions at the final race completing a total of 379 and 376 laps respectively of 24 hours
of Le Mans, and is currently 2nd in the overall championship. [23]
Figure 6-4: Two energy recovery systems of Porsche 919 and 8MJ energy storage [24]
The other car in the segment of Endurance racing using similar Heat Recovery
system is the Porsche team with its Porsche 919 Hybrid. The Porsche uses a 2L
turbocharged V4 engine with a energy recovery system. The Porsche team has taken a
different approach to the recovery system by using independent turbines to run the motor
generators instead of incorporating the recovery system in the turbochargers. The Porsche
will use the highest capacity of 8MJ Lithium-ion energy pack allowed by the regulations
[25]

6.3 Concepts and Prototypes
Apart from the motorsport industry, there is considerable interest by passenger car,
commercial vehicle, bus and truck manufacturers in similar technology. One company
actively looking for ways to productively extract energy from exhaust is BMW. One such
technology being considered is called “Turbosteamers” where BMW uses the hot exhaust
gases to evaporate the fluid and fed to an expansion unit linked to the crankshaft of the
engine providing 15% greater fuel efficiency, 14 additional horsepower and 15 lb-ft. of
added torque. The tests were carried out on a 1.8L V4 BMW engine. The system
according to BMW is compact enough to be installed in existing models and might be the
daylight of production in around 10 years. [26] The Turbosteamers are thus in principle
similar to the cogeneration used in power plants to recover heat that is wasted. The main
hurdles in developing a turbosteamer is the efficient storage of heat that does not disrupt
normal engine operation and proper compact packaging of the unit. As of 2011. BMW has
successfully managed to install and carry out preliminary tests of the turbosteamer on the
BMW 5 series saloon.
Figure 6-5: BMW Turbosteamer Units for Automobiles [27]

Figure 6-6: Turbosteamer Vehicle Integration [28]
Another technology that is being considered is the Thermo-Electric Generators
(TEG). Using the thermoelectric property of metals and metalloids, also known as the
Seebeck effect, BMW plans to salvage heat from the exhaust of vehicles by using
semiconductors at different temperatures. Such technology is already in use by NASA,
and BMW has managed to generate 200-600 Watts of electricity through this technology
and plans to increase it up to 1000W. A BMW X6 prototype has been developed by a
project funded by US Department of Energy. [29] [27]

Figure 6-7: Vehicle Integration of TEG in BMW X6 [30]
Another manufacturer developing similar systems is the Renault Group. Apart
from the Formula 1 engines made by Renault that use waste heat recovery as a part of "All
for Fuel Eco" initiative. The Rankine cycle being used to convert hot gases into electricity
can provide a reduction of long distance vehicle fuel consumption by 6% to 10%. [31]
This technology seems to be specially suited to trucks with long mileages and large
payloads.
Renault is also developing energy recovery systems for its trucks and cars in
collaboration with the Volvo Group. The project named The Renoter (Recuperation of
exhaust ENergy from a mOtor via ThERmo-electricity) Project. The project began in
2008 and went on till 2011. Primarily the project focused on the use of thermoelectric
generators for recovery of waste heat and generation of electricity. Unique heat exchanger
models were created and various thermoelectric metals were tested for various
temperature ranges. After extensive testing, 1kW of energy gain in trucks and 300W in
passenger cars was achieved. According to the report, the technology seems to be in sight
but will take time to optimize the cost vs efficiency parameter. [32]

Honda also is developing waste heat recovery solutions for its range of hybrid
vehicles based on the closed loop Rankine cycle known as Rosebro. First, heat from the
car's catalytic converter is used to boil water. The high-temperature steam (400-500 °C)
produced then turns an electric generator, before a condenser finally cools the steam back
into water. The energy recovered from Rankine cycle systems is thrice the amount of
energy recovered by regenerative breaking for Hybrid Vehicles. According to
Honda, under normal driving conditions, the steam system recovered three times as much
electric power as the hybrid's regenerative braking system. Unfortunately, however, the
4% improvement in overall vehicle efficiency that resulted is not high enough to warrant
commercialization, Honda claims. [33]
Cummins Turbo Technologies unveiled in March 2013 a waste heat expander
prototype for the same purpose as a part of the participation in U.S. Department of
Energy’s SuperTruck initiative. The company aims to improve fuel efficiency by 10%
with the use of such systems. The waste heat turbine expander prototype was displayed
alongside Cummins Turbo Technologies latest range of highly efficient turbocharging
solutions, namely electronic variable geometry turbochargers, two-stage turbochargers,
small turbochargers and the turbocompound system. [34]

7. FUTURE SCOPE
A waste heat recovery device can take many forms and need not be limited to the one
we have created. It can Take various forms and perform various actions. Even though a
turbocharger or a turbine is the most efficient way of harnessing the energy of the exhaust
gases, using it to generate electricity might not be the only way to utilize the energy
recovered by it.
Below are some ideas we think are possible to be incorporated into the system.
7.1 Turbo Air Conditioning
The mechanical energy received from the turbocharger can be used to run a
compressor of the Air Conditioning system of the car as the compressor too requires
rotational motion for its working
However, the torque requirements of a compressor are greater than a D.C
generator or an alternator. We observed that the turbocharger we used for generating a
mechanical drive was not sufficient to run the compressor. The small turbocharger
employed by us had a small shaft diameter unable to bear the loads required for running
the compressor. We believe such a system can reduce the load on the engine giving
greater efficiency.
Following is the working of air condition which will help better understand the concept.
Working of air-conditioning
Air conditioning like it says 'conditions' the air. It not only cools it down, but also reduces
the moisture content, or humidity. All air conditioners work the same way whether they
are installed in a building, or in a car. The fridge or freezer is in a way an air conditioner
as well. Air conditioning is a field in its own right, but we'll stick to the main points or a
car's air conditioning and the main parts used and a few hints to keep the air-con system
running properly.

A number of people don't realise that turning on the air conditioning actually reduces the
number of miles per gallon of your car. There is energy used in removing the heat and
moisture from the air in the car, and this consumes petrol because of the extra engine
load.
Air conditioning's main principles are Evaporation and Condensation, then
Compression and Expansion.
Hard tubing and flexible hoses connect all the actual components of the air conditioning
Figure 7-1: Schematic working of air-conditioner

in your car. Evaporation and condensation, expansion and compression are the physics of
why it works. There are five main components to the whole system, namely the
Compressor, Condenser, Receiver-dryer, Expansion valve, and the Evaporator.
The fluid that passes around the whole system is the refrigerant. The refrigerant’
can evaporate at a low temperature, and then condense again at a higher pressure. In the
bad old days, R-12 was the refrigerant used in almost all cars. It was widely available;
however, it was found to be a contributor to the hole in the earth's ozone layer as it was a
chlorofluorocarbon (CFC). These refrigerants were discontinued, and all cars after 1996
use a non-CFC fluid called R-134A which is kinder to the environment.
So, here are how all the various parts of a car's air conditioning works:
Compressor: The compressor is the work horse of the air conditioning system, powered
by a drive belt connected to the crankshaft of the engine. When the aircon system is
turned on, the compressor pumps refrigerant vapour under high pressure to the condenser.
Condenser: The condenser is a device used to change the high-pressure refrigerant vapor
to a liquid. It is mounted in front of the engine's radiator, and it looks very similar to a
radiator. The vapour is condensed to a liquid because of the high pressure that is driving it
in, and this generates a great deal of heat. The heat is then in turn removed from the
condenser by air flowing through the condenser on the outside.
Receiver: The now liquid refrigerant moves to the receiver-dryer. This is a small
reservoir vessel for the liquid refrigerant, and removes any moisture that may have leaked
into the refrigerant. Moisture in the system causes havoc, with ice crystals causing
blockages and mechanical damage.
Expansion Valve: The pressurised refrigerant flows from the receiver-drier to the
expansion valve. The valve removes pressure from the liquid refrigerant so that it can

expand and become refrigerant vapour in the evaporator.
Evaporator: The evaporator is another device that looks similar to a car radiator. It has
tubes and fins and is usually mounted inside the passenger compartment behind the fascia
above the footwall. As the cold low-pressure refrigerant is passed into the evaporator, it
vaporises and absorbs heat from the air in the passenger compartment. The blower fan
inside the passenger compartment pushes air over the outside of the evaporator, so cold air
is circulated inside the car. On the 'air-side' of the evaporator, the moisture in the air is
reduced, and the 'condensate' is collected and drained away.
Compressor: The compressor then draws in the low-pressure refrigerant vapour to start
another refrigeration cycle. The refrigeration cycle then runs continuously, and is
regulated by the setting of the expansion valve.
The whole process is reasonably simple when explained like that. All air conditioning
systems work on the same principle, even if the exact components used may vary slightly
between car manufacturers.

7.2 TURBO ALTERNATOR
As we know that the alternator is continuously running and the load on alternator
increases as the demand of current supply increases by the vehicle, now a days almost
every vehicle have many electronic components which is fulfilled by the alternator
therefore load on alternator is increased which then increased load on the engine and
hence the efficiency of the engine decrease.
Despite their names, both ‘DC generators’ (and 'dynamos') and 'alternators' initially
produce alternating current. In a so-called 'DC generator', this AC current is generated in
the rotating armature, and then converted to DC by the commutator and brushes. In an
'alternator', the AC current is generated in the stationary stator, and then is converted to
DC by the rectifiers (diodes).

8. Conclusions
A large part of the energy produced during combustion process in the engine cylinders
escapes with exhaust gases. By the use of a turbogenerator, some part of this energy can
be utilized.
In our endeavour to create a working model of this concept we faced several
problems and hurdles that we were unable to overcome in the limited time. The mismatch
of the shaft size with the generator and the difficulty of finding either a suitable generator
or a shaft for the turbine being some of the most enduring problems. With further
improvement and better resources, we hope to create a successful model that can give
substantial output.

9. REFERENCES
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Table of Figures
Figure 3-1: Sankey diagram of power flow in a combustion engine ...................................................................10
Figure 4-1: Turbocompunding Schematic Layouts ..................................................................................................14
Figure 4-2: Electric Turbocharger [3].........................................................................................................................15
Figure 5-1: Premier Padmini Engine...........................................................................................................................17
Figure 5-2: Frame for Mounting ..................................................................................................................................19
Figure 5-3 .........................................................................................................................................................................20
Figure 5-4: Construction of a DC Generator .............................................................................................................22
Figure 5-5: Fleming's Right Hand Rule [35]...............................................................................................................25
Figure 6-1: Renault Energy F1-2014 Engine ..............................................................................................................26
Figure 6-2: Parts of F1-2014 Engine [19] ...................................................................................................................28
Figure 6-3: Audi R18 e-tron Quattro [21]..................................................................................................................29
Figure 6-4: Two energy recovery systems of Porsche 919 and 8MJ energy storage [24] ...............................30
Figure 6-5: BMW Turbosteamer Units for Automobiles [27] ...............................................................................31
Figure 6-6: Turbosteamer Vehicle Integration [28] ................................................................................................32
Figure 6-7: Vehicle Integration of TEG in BMW X6 [30] .........................................................................................33
Figure 7-1: Schematic working of air-conditioner...................................................................................................36

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