Duke engine technology (redial engine)

GUJARAT TECHNOLOGICAL UNIVERSITY
Chandkheda, Ahmedabad
Affiliated
Silver Oak Collage of Engineering & Technology
A
Project Report
on
DUKE ENGINE
Design Engineering – 3rd
Sem
(B.E. 3rd
SEM)
Submitted by:
Sr. Name of Student
1. ACHAL PATEL
2. JAY PATEL
3. BONY PATEL
4. HET PATEL
Mr. Vatsal Chaudhari
(Faculty Guide)
MR. Mit K Shah
(Head of the Department)
Academic Year (2015-16)

STUDENT DETAILS
PATEL ACHAL
I AM PURSUING BE DEGREE FROM SILVER OAK COLLAGE OF ENGINEERING &
TECHNOLOGY. MECHANICAL & AUTOMOBILE FIELD MANAGER OF BIGGEST COMPANY.
EMAIL ID:achalpatel2@gmail.com
MOBILE NO.9558004560
PATEL JAY
TECHNOLOGY.
EMAIL ID:
MOBILE NO.
PATEL BONY
TECHNOLOGY.
EMAIL ID:
MOBILE NO.
PATEL HET
TECHNOLOGY.
EMAIL ID:
MOBILE NO.

CERTIFICATE
This is to certify that this work entitled “DUKE ENGINE” represents the patel achal (15MED48), patel jay
(15MED40), patel bony (15MED42), Patel het (15MED43), of 3rd
sem BE in Mechanical Engineering has
satisfactorily completed term work in DESIGN ENGINEERING-1A at SILVER OAK COLLEGE OF
ENGINEERING & TECHNOLOGY , AHMEDABAD-60, Gujarat, during the academic year 2015-2016 and
their work is completed and found satisfactory.
Mr. Vatsal Chaudhari Prof. Mit K Shah
(Faculty guide) (head of department)

ACKNOLEDGEMENT
In these years of diploma engineering our faculty Mr. Vatsal Chaudhary has guided us to achieve a goal and
made us capable to complete our Mini Project work successfully. So we would like to take this chance to thank
our Project guide, Lab assistants and college with whose support and skillful guidance has made us such as that
we would be proud of wherever we go and always be confident in achieving our goals. Firstly we would like to
give our sincere regards to all our Faculty Members of Mechanical Engineering Department for giving their
excellent guidance and who gave us the confidence that we can complete this project successfully. All Faculties
of mechanical branch have shared their valuable ideas and industrial knowledge about for this project and that’s
why we are also thanking them for their help. We are thankful to our project guide Mr. vatsal sir, We are
thankful that we got the chance to work under his guidelines and our sincere and heartily regards to them. We
would also like to give vote of thanks to Mr. Mit k Shah who has given us permission to carry out this Project
work and for providing with the material which initiated our Project work. Finally last but not the least we are
very much thankful to our Team Members, Friends and our Principal Prof. Saurin Shah for their kind support
and co-ordination during the entire span of Education till now in silver oak college of Engineering and
Technology.
PATEL ACHAL
PATEL JAY

ABSTRACT
Duke i.c. Engine
Duke engines are in an advanced stage of developing a unique high-speed, valve-less 5 cylinders, 3 injectors,
axial internal combustion engine with zero first-order vibration, significantly reduced size and weight, very high
power density and the ability to run on multiple fuels and bio-fuels. The duke engine is suited for many uses
including marine, military automobile, light aircraft and range extender applications. The duke engine’s 5
cylinder, 3 liters, 4-stroke internal combustion engine platform with its unique axial arrangement is already in
its 3rd generation. During development the duke has been tested at mahle powertrain in the uk & in the usa, and
test results are available. The duke's unique counter rotation, 3 dimensional, almost vibration free motion and
the innovative methodology employed to achieve this, addresses previous limitations that have prevented the
commercialization of axial piston engines to date, especially at higher power and speed. The current engine can
be run on any suitable spark ignition fuel. Kerosene/jet a1 operation has been successfully tested. It is expected
with further development to be able to operate on all appropriate fuels, including ethanol/methanol and blends,
bio ethanol, lpg, cng, hydrogen, kerosene and diesel. The duke engine's lower component count (only 3 sets of
injectors and ports for 5 cylinders with no valve train), coupled with potentially lower production costs, make
for savings in manufacturing and operation. And the duke uses existing materials and manufacturing processes
in its construction. Duke engines is now at a third generation of the engine and currently developing the next
generation of the technology, including running with kerosene and biofuels and exploring the unique design
characteristics of the duke engine to allow variable compression ratios. The duke is currently in its 3rd
generation running prototype. The engine has been successfully tested at university of auckland and mahle uk &
usa dynamometers and test facilities, (data available), with systems co-development by expert uk partners. Duke
engines’ mechanical systems innovations can be developed beyond the engine platform to pumps, gearboxes
etc.

INDEX
Sr. No. TITLE PAGE NO.
STUDENT DETAILS I
CERTIFICATE
ACKNOWLEDGEMENT
ABSTRACT
1 CHAPTER-1
INTRODUCTION
1.1 PRODECT
DEVELOPMENT CANVAS
TECHNOLOGY
OVERVIEW
CHAPTER-3
ADVANTAGES

LIST OF FIGURE
Sr. No. TITLE Page No.
1 Ksjdvb 1

CHAPTER -1
DESIGN ENGINEERING
Introduction
A Design Engineer is a general term that covers multiple engineering disciplines including electrical,
mechanical, chemical engineer, aeronautical engineer, civil, and structural/building/architectural engineers. The
uniting concept is a focus on applying the 'engineering design process, in which engineers develop new
products or processes with a primary emphasis on functional utility. While industrial designers may be
responsible for the conceptual aesthetic and ergonomic aspects of a design, the design engineer usually works
with a team of engineers and other designers to develop conceptual and detailed designs. They may work with
industrial designers and marketers to develop the product concept and specifications, and may direct the design
effort. In many engineering areas, a distinction is made between the design engineer and the planning engineer
in design; Analysis is important for planning engineers, while synthesis is more paramount for design engineers.
A Test Engineer is also sometimes contrasted from design engineers, as test engineers tend to focus more on the
evaluation and analysis of prototypes, feasibility of manufacturing and testing (rather than their conception).
When the design involves public safety, the design engineer is usually required to be licensed, for example a
Professional Engineer in the U.S and Canada. There is usually an 'industrial exemption' for design engineers
working on project internal to companies and not delivering professional services directly to the public.

1.1
PRODECT DEVELOPMENT CANVAS
Fig.1 cancas
The physical size, weight and shape of an engine package imposes large constraints on the Design Engineer and
heavily impacts performance, production, production cost, storage and shipping of the engine. The Duke
Engine's unique design delivers an engine package that produces unmatched gains across all these factors,
allowing unique design freedoms combined with an ease of production, shipping and storage.
The Noise, Vibration and Harshness of an engine are not only important from an engineering perspective but
impact on the entire system of which the engine is just a part. The Duke Engine offers outstanding positive
NVH benefits
The Duke Engine can overcome many of the limits of the conventional combustion engine and achieve power
densities approaching those of Formula 1 engines as a port area greater than 37% bore area is practicable in
future Duke Concepts, offering greater potential intake flow area than conventional engines. The lack of
reciprocating poppet valves also removes the practical limitation that this system imposes on engine operating
speed.

1.1.1
AEIOU SUMMARY :-
Fig. 2
As well as Automotive applications the Duke Engine lends itself well to Marine, Aircraft and Generator/Utility
Range Extender options. The output shaft, being 'geared down' to 5/6 of the piston reciprocating speed, allows
the 'engine-out' torque to be higher and maximum torque to be developed at lower speeds. The Duke Engine is
generally well suited to many applications of 40kW or greater.
In a horizontal shaft installation, the Duke engine offers a very low profile, a low centre of gravity and low
weight that will improve the options for installing the engine under deck or seating. All of which offer benefits
to craft handling and performance.
The Duke Engine lends itself well to Marine, Aircraft and Generator/Utility, Automotive and Hybrid electric
vehicle Range Extender Applications. The Duke output shaft, being intrinsically 'geared down' to 5/6 of the
piston reciprocating speed, allows the 'engine-out' torque to be higher and maximum torque to be developed at
lower speeds.

1.1.2
EMPATHY SUMMARY
Fig. 3
The Duke Engine features a low speed, mono-plane sliding seal arrangement with otherwise conventional
cylinders. Potential engine out emissions performance is estimated to be between Wankel and conventional
engines. Due to high detonation resistance and 3 runner exhaust manifold for 5 cylinders; The Duke engine
offers efficient full load operation at Lambda 1, and has a low heat loss rejection area pre-catalyst. The Duke
engine offers an after-treatment friendly prospect to address emissions requirements.
The Duke engine already exhibits excellent NVH potential and good package, weight and efficiency potential.
Licensing options are open and with development there is great potential for increased performance and
optimization to meet specific application requirements.

1.1.3
IDEATION CANVAS :-
Fig.4
The Duke Engine is already in advanced stages of development. Multicylinder engines are operational and have been
tested in Australasia, Europe and in the USA.. The Duke engine’s 5 cylinder, 3 litre, 4-stroke internal combustion engine
platform with its unique axial arrangement is already in its 3rd generation. During development the Duke has been
tested at Mahle Powertrain in the UK & in the USA, and test results are available.
Duke Engines are in an advanced stage of developing a unique high-speed, valve-less 5 cylinder, 3 injector
power density and the ability to run on multiple fuels and bio-fuels. The Duke engine is suited for many uses
including marine, military, automobile, light aircraft and range extender applications.
The Duke Engine has IP protection. Throughout the development process, Duke Engines has filed patent applications to
protect its technology.

1.1.4
Fig.4
Mahle Powertrain Development Report, 2007/8
Geoff Martin, ex Engineering Manager Ford Motor Company NZ, 2008
Prof. Peter Squires, University of Canterbury, 2008
Hugh Blaxill, Chief Engineer, R&D, MAHLEPowertrain Ltd., 2010
Dr. Mike Fry, Engine Development Expert, Principal Ngenious Ltd. UK,ex Cosworth Head of R&D, 2011
“..I still firmly believe in the ultimate success of the engine,it’s systems and the overall concept…”
Bob McMurray, CEO A1 RacingTeam, NZ, ex McLaren Formula 1

Chapter-2
Technology Overview
Duke Engines are in an advanced stage of developing a unique high-speed, valve-less 5 cylinder, 3 injector
power density and the ability to run on multiple fuels and bio-fuels. The Duke engine is suited for many uses
including marine, military, automobile, light aircraft and range extender applications.
The Duke Engine is already in advanced stages of development. Multicylinder engines are operational and have been
tested in Australasia, Europe and in the USA..
The Duke engine’s 5 cylinder, 3 litre, 4-stroke internal combustion engine platform with its unique axial arrangement is
already in its 3rd generation. During development the Duke has been tested at Mahle Powertrain in the UK & in the USA,
and test results are available.
The Duke Engine features many technology breakthroughs.
The Duke's unique counter rotation, 3 dimensional, almost vibration free motion and the innovative methodology
employed to achieve this, addresses previous limitations that have prevented the commercialisation of axial piston
engines to date, especially at higher power and speed.
The Duke offers designers greater freedom.
Duke’s axial geometry creates a very compact cylindrical package, allowing for a wide range of design applications,
limited space fit, aerodynamic optimization and ease of installation.
The Duke Engine delivers huge weight and size savings
. In comparisons made to conventional IC engines with similar displacement, the Duke engine was found to be up to 19%
lighter and up to 36% smaller.
The Duke Engine has negligible 1st-order or 2nd-order Vibration.
The Duke’s nutating reciprocator leads to very low angles of con rod articulation resulting in a near sinusoidal
reciprocating motion. This combined with the counter-rotating cylinder group and crankshaft in the Duke engine delivers
near perfect mechanical balance resulting in a very low vibration engine.
The Duke Engine delivers high thermodynamic efficiency.

The absence of hot valves in the favourably shaped combustion chamber allows high compression ratios for efficient
operation on low octane fuels. With only 3 exhaust headers for 5 cylinders there is a low surface area for heat loss prior
to any catalytic converter, offering a potential catalyst light-off benifit.
The Duke Engine offers wide fuel flexibility.
The current engine can be run on any suitable spark ignition fuel. Kerosene/Jet A1 operation has been successfully
tested. It is expected with further development to be able to operate on all appropriate fuels, including
Ethanol/Methanol and blends, Bio ethanol, LPG, CNG, Hydrogen, Kerosene and Diesel.
The Duke Engine is far less complex than traditional IC engines.
The Duke engine's lower component count (only 3 sets of injectors and ports for 5 cylinders with no valve train),
coupled with potentially lower production costs, make for savings in manufacturing and operation. And the Duke uses
existing materials and manufacturing processes in its construction.
Duke Engines is committed to Research & Development, with further advances already underway.
The Duke is currently in its 3rd generation running prototype. The engine has been successfully tested at University of
Auckland and Mahle UK & USA dynamometers and test facilities, (data available), with systems co-development by
expert UK partners. Duke Engines’ mechanical systems innovations can be developed beyond the engine platform to
pumps, gearboxes etc.
The Duke Engine has IP protection.
Throughout the development process, Duke Engines has filed patent applications to protect its technology.
Duke Engine Financial Supporters.
In addition to the initial founders inputs, Duke Engines has enjoyed support financial and otherwise from New Zealand
Trade & Enterprise, TechNZ, Ministry of Science and Innovation and private investors including the Gallagher Group
Duke Engines - the Future.
Duke Engines is now at a third generation of the engine and currently developing the next generation of the technology,
including running with kerosene and biofuels and exploring the unique design characteristics of the Duke engine to allow
Variable Compression Ratios.
Duke Engines is actively seeking partners right now to join in developing this visionary technology around application
specific parameters.

CHAPTER-3
ADVANTAGES:-
3.1
The Low Vibration Duke Engine
The Noise, Vibration and Harshness of an engine are not only important from an engineering perspective but
impact on the entire system of which the engine is just a part. The Duke Engine offers outstanding positive
NVH benefits.
Fig.5
Mechanical forces from rotating and reciprocating systems in the axial arrangement of the Duke engine are very
different from any conventional engine. The sinusoidal reciprocating force from each cylinder combined with
the inertial forces from the nutating body sum up to leave a simple first order balance couple, which can be fully
resolved using basic fixed masses on the Z crankshaft. The Nutating reciprocator leads to very low angles of
con rod articulation (<3Deg deviation from cylinder axis) resulting in near sinusoidal reciprocating motion,
meaning there are negligible secondary or higher order vibration forces generated within the reciprocating
system. This is in stark contrast to conventional engines where unresolved second order vibrations can dominate
the mechanical vibration levels, as in the case of a conventional in-line 4-cylinder engine. Many conventional 4-
cylinder engines are fitted with twin balancer shaft systems driven at twice engine speed to enable such engines
to meet market acceptance levels.
It is reasonable to say that the mechanical balance of the Duke Engine is near perfect, without the added
complexity of additional balance shafts etc.
Fig.6
If a variable compression ratio Duke engine is considered, the near perfect balance could be maintained
throughout any compression ratio variation. Many mechanisms proposed to achieve variable compression ratio
in conventional engines introduce or change vibrations between low and high ratio positions. The counter-
rotating cylinder group and crankshaft in the Duke engine provide the dynamic equivalent of twin-contra-
rotating flywheels. Torque cancellation occurs between the contra rotating flywheels during speed fluctuations.
As a result the Duke engine sees a reduction in the instantaneous torque oscillation at engine mounts, compared
to a single flywheel conventional engine.

Mechanical Vibration is a standout benefit area for the Duke Engine.
3.2
A Variable Compression Ratio Duke Engine
The specific nature of a practical variable compression ratio mechanism for the Duke engine has not been
finalized.
However, the axial layout lends itself to variable compression ratio with relative ease, and it is likely that
a variable compression ratio Duke engine is a real and potentially attractive proposition.
VARIABLE COMPRESSION RATIO
Variable Compression Ratio is being actively researched by many automotive OEM's such as GM,
Nissan, Honda, Yamaha, and Mercedes to name a few. VCR is seen as a major potential contributor in
improving the fuel efficiency of internal combustion engines. While actively researched, it has not yet
entered full production with anyone, the closest to production being the Saab SVC engine of 2002.
A significant reason for not reaching production is the difficulty of achieving Variable Compression
Ratio in traditional engine architectures. Ref.1 provides a useful overview of some approaches considered
to date.
BASIC THEORY
Spark ignition cycle efficiency is dependent upon the degree of compression and expansion achieved in the
operating cycle. In a practical engine the ratios of compression (trapped volume/minimum volume) and
expansion (full expanded volume/minimum volume) are similar. In a typically accepted simplification this can
be considered a single ratio of the minimum cylinder volume to maximum geometric cylinder volume or,
simply the "compression ratio". If further simplifications such as no leakage, no heat transfer between walls and
fluid, ideal gas behaviour and zero duration heat replacement are adopted, the Idealized
Otto cycle is then realized:
Otto cycle thermal efficiency (η) = 1 − r(1 − γ)
Where r = compression ratio and γ = Ratio of specific heats for the working fluid (1.4 if approximated to air).
Fig.7

Otto cycle efficiency is not achievable in practice, but as theoretical maximum cycle efficiency it is a useful
reference comparator for real world spark ignition cycles.
Generally a high compression ratio results in high cycle efficiency, while a lower compression ratio results in
lower structural forces and a higher achievable charge mass before the onset of detonation. Most practical
engines have a fixed compression ratio which is selected to give a working compromise between efficiency and
performance requirements.
The higher the specific output of the engine, the greater is the compromise between part load and full load
optimum compression ratios, and the greater any benefit from being able to vary the compression ratio may be
expected to be.
As an example, where an optimum compression ratio might be set at 25:1 at part load Vs a typical value of 10:1
for a fixed compression ratio engine we see a 20% gain in Otto cycle efficiency (Fig 2). While this is a gain in
the theoretical maximum efficiency only, it is a useful guide to show the order of thermal efficiency gains
possible.
3.3
THE DUKE ENGINE & VARIABLE COMPRESSION RATIO
Variable compression ratio in itself is a useful method of enhancing engine efficiency. However the greatest
value may be derived from variable compression ratio when seen as an enabling element for other technical
approaches.
Downsizing SI engines. There is a current trend towards downsizing or using a small displacement high
specific output engine in place of a larger conventional engine. This is typically achieved using aggressive
pressure charging to maintain the performance associated with a larger conventional engine. Downsizing places
a greater compromise on a fixed compression ratio between full load performance and part load efficiency and
as such there is a correspondingly greater benefit from introducing a variable compression ratio. Downsizing
with variable compression ratio has been estimated as being capable of providing benefits of up to 35% in drive
cycle fuel efficiency (Ref 1). The Saab SVC (pre production) variable compression ratio engine (Ref 2) was a
production feasible downsized engine using this concept to achieve a 25% reduction in drive cycle fuel
consumption in a "D" category vehicle (Saab 95).
HCCI. Homogenous Charge Compression Ignition (HCCI) HCCI is system of controlled auto ignition of
homogenous pre-mixed charge. The combustion of more leaner mixtures is possible with HCCI than with spark
ignition. Very lean HCCI operation offers large improvements to part load efficiency and (particularly NOx)
emissions (Ref 4). The practicability of operating in HCCI mode is greatly enhanced by the ability to create a
fast response variation of the compression ratio.
Fuel quality tolerance. Fuel quality (octane rating) in specified market is one of the key determinants of
conventional spark ignition compression ratio selection. High octane fuel availability generally enables higher
compression ratio's to be specified, with improved fuel efficiency. Variation of fuel quality across geographic
markets requires that the compression ratio of any global vehicle model must be compatible with the lowest fuel
quality in the target market areas. This often results in compression ratio (and therefore fuel efficiency) being
lower than optimum in some markets. Variable compression ratio would be one method of making global
products more optimised across a range of supported markets.

Flex Fuel/Multi-Fuel capability. In an extension to the Fuel octane tolerance effects discussed above, multi
fuel operation places even greater variation in optimum compression ratio. The effective octane rating of
various fuels ranges from 135 for Methane to <30 for traditional compression ignition fuels (Ref 3). Variable
compression ratio would be a key enabling technology in producing a practicable spark ignition engine
operating efficiently on a wide range of fuels.
Fig.8
Diesel
Diesel engines are trending towards lower compression ratios currently which allows for high outputs and boost
pressures within structural limits. However low compression ratio reduces part load efficiency and the ability to
start at low temperatures.
Variable compression ratio would in principle allow a diesel engine to achieve higher full load output with
improved part load efficiency while improving cold start capability. Achieving Variable CR on a Diesel engine
holds a few more challenges than with spark ignition due to the sensitivity of variation in piston position
relative to cylinder head and injector at TDC.
3.4
DUKE ENGINES’ WEIGHT, SIZE & SHAPE BENEFITS
The physical size, weight and shape of an engine package imposes large constraints on the Design
Engineer and heavily impacts performance, production, production cost, storage and shipping of the
engine. The Duke Engine's unique design delivers an engine package that produces unmatched gains
across all these factors, allowing unique design freedoms combined with an ease of production, shipping
and storage.
Package and design prospects*
Package potential. The Duke engine is essentially cylindrical in shape, with the output shaft on the axis of the
cylinder and exiting one or both ends. Importantly all of the fluid porting and electrical connections can be on
one end face.
The outer Diameter of the Duke engine casing is driven by the Bore of the cylinders that it contains. An
optimised Duke engine of automotive size range can be designed with an external diameter of approx 3.4 times
the bore.
An over square (bore to stroke of ratio 1.2) 3.0L Duke engine would have an optimized external case diameter
of approx 330 mm, with a 5.2L Duke fitting inside a 400mm diameter.
The current prototype V3 (5cyl 3L) long engine dimensions are 641mm L x 370mm W x 375mm H and so fits
in a nominal cuboid "packing crate" of 89L, and has a nominal external diameter of 373mm. The current height
and width have the scope to be reduced further.

A 1.0L (~100 HP) engine would be about 230mm (9") optimized diameter, allowing it to fit inside a
standard sized"carry on" airline bag.
ENGINE LENGTH
The length of the engine "long block" (engine without ancillaries and manifolds)is a more complex function
depending on Stroke and other system and drive features, so isn't quite as simple to quantify as diameter. The
current 3.0 Litre V3 Duke prototypes long block is 641mm long.
Duke Range extender 1.25Ltr concept long block is 466mm long. Both of these Duke examples are not fully
optimised for length, but compare favourably with conventional engines, even when in V configuration.
Weight size and shape continued –
Comparisons have been done between the current V3 3.0L Duke engine and comparable automotive engines.
The external volume and mass of the Duke V3 has been compared to some conventional automotive engines,
including the BMW 3.0L M54B30, Nissan 3.5L VQ35DE and Toyota 3.0L 1MZ-FE (see comparison sheets
previous and below)
The "Crate volume" of these comparative engines being measured as between 275L and 326 L making the Duke
engine "Crate" at 89L, up to 70% smaller. The BMW and Toyota competitor engines and Duke engine were
also "shrink wrapped" in plastic and immersed in water to closer estimate actual engine volume and make fairer
comparisons between the different shapes.
Fig.9 fig.10

SHIPPING SIZES
The diagrams to the left and below give a practical indication of the size, volume and shipping weight benefits
of the current Duke engine 'crate' package compared to the Toyota and BMW.
3.5
Duke Engines High Power Density
The Duke Engine can overcome many of the limits of the conventional combustion engine and achieve
power densities approaching those of Formula 1 engines as a port area greater than 37% bore area is
practicable in future Duke Concepts, offering greater potential intake flow area than conventional
engines. The lack of reciprocating poppet valves also removes the practical limitation that this system
imposes on engine operating speed.
PORT AREA
Modern Formulae 1 engine operates at high speed (approx 20,000 rpm), enabled by exotic lightweight
reciprocating components and pneumatically sprung valve operating system. The required air flow is achieved
through large intake valves requiring a suitably large cylinder bore. In conventioanal high performance 4 valve
engines, intake valve flow area is a limiting factor in engine performance. Intake valve area limit of approx 32%
of bore area is a basic geometric limitation( 2 x intake valves, each limited in diameter to about 40% of the
Bore), with the available air flow area being significantly
Fig.11
smaller than the valve head area, at typically less than (30% bore area). The inlet flow area potential of the
Duke engine is approx 25% greater than that of a current Formula 1 engine of similar bore. In the key areas of
intake port area and maximum valve/port operating speed, the Duke engine is just not limited to the same extent
as conventional engines. In current V3 and V3i versions of the Duke engine port area is less than the potential,
limited by legacy architecture. Also while the speed limits of the V3 was around 3500 rpm, the V3i target using
revised architecture is 6000 rpm. Hence while the V3 power is 105kW, the V3i target power is “only” 137kw
Performance potential for a "next generation" Duke offers a prospect of naturally aspirated 3.0Ltrs developing
300 kW operating at 8000 rpm from a 100 kg dressed engine (approx 80kg bare engine block). This next
generation 3.0Ltr /300kW and 3kW/kg, long engine block would also fit in an 80L packing crate.
This power density target is seen as practically feasible for the next generation of the Duke engine. Greater
performance potential (Intake area >>40% bore, speed >> 8000 rpm) would be expected within the theoretical
limits that have yet to be explored. As such the performance potential of the Duke engine is outstanding.

THROTTLE RESPONSE
The reduced crank mass also possesses reduced rotational kinetic energy compared to conventional crankshafts
and the cylinder block, pistons, and reciprocator spin (in the 5 cylinder engine) at only 1/5th of crank speed.
Overall, total rotational kinetic energy is lower than for the equivalent internal combustion engine, meaning
there is less resistance to acceleration and deceleration of the engine. The engine therefore has a very quick
throttle response.While the naturally aspirated performance prospects of the Duke engine are excellent, pressure
charging is also attractive. In most respects the Duke engine could be expected to respond to pressure charging
in ways similar to a conventional engine. The demonstrated detonation resistence of the Duke engine offers the
prospect of maintaining higher compression ratios with high boost pressures in highly rated SI engines.
The Axial arrangement of the Duke engine also lends itself to variable compression ratio, improving the full
load power/partload efficiency trade off typically encountered in fixed compression ratio, highly pressure
charged engines.
3.6
THE MULTI-FUEL DUKE ENGINE
The current spark ignition (SI) Duke engine offers the potential to operate on all of the alternate fuels
generally considered suitable for a conventional SI engine with little or no development. "Bio-fuels" are
alternative fuels derived from vegetable feedstock that can be formulated to provide a basis or blending
component for many of the alternate SI and Compression Ignition (CI or "Diesel Cycle") fuels, the most
common being bio-diesel (for CI) and bio-ethanol (for SI).
WHAT ARE ALTERNATIVE FUELS?
Alternative fuels fall into 2 groups
1. Those generally suitable for SI operation include: Gasoline(s), Methane, LPG, Hydrogen, Ethanol, Methanol,
2. Those generally suitable for CI operation include: Diesel, Dimethyl ether (DME), bio-diesel, vegetable and
animal oils, Kerosene.
THE DUKE ENGINE ADVANTAGE
THE DUKE ENGINE ADVANTAGE
The SI Duke engine has shown a resistance to detonation (potentially damaging auto ignition) that is superior to
conventional combustion engines. This is in part due to lower maximum wall temperatures in the combustion
chamber relative to a conventional engine, stemming from the lack of hot exhaust valves in the Duke
combustion system.

DUKE ENGINES AND COMPRESSION IGNITION
Duke engines operating on a Compression Ignition cycle are envisaged, but not currently developed.
By the nature of CI engines, high cylinder pressures lead to high mechanical loads requiring heavier engine
structures. Diesel engines historically have much heavier engine structures than SI engines, and so have been
absent from weight critical applications such as outboard motors and aircraft.
Fig.12
As with the current SI Duke engine, future CI Duke engines may be expected to yield weight advantages over a
conventional engine and so offer the prospect of extending the use of CI engines in some weight critical
applications.
A Duke CI engine would be expected to operate with 3 injectors for a 5 cylinder engine, offering a major cost
advantage with modern Diesel injectors being particularly expensive.
A Duke engine developed to run on a CI cycle may be expected to run on all alternate fuels typically considered
suitable for CI Diesel, with all the relative ease of operation and benefit of operation similar to that with their
use in conventional CI engines.
THE DUKE ENGINE ON KEROSENE
The Duke detonation resistant characteristic opens up an exciting prospect of operating the Duke engine on
kerosene. Operating a 4 stroke SI Duke engine on kerosene based fuels holds many attractions for aviation and
military applications, and offers an opportunity to offer a unique product into a significant market gap.
Initial testing with an unmodified Duke engine has given encouraging results, even with it’s higher than
conventional compression ratio of 12.5:1. A Spark Ignition Duke engine optimised to run on kerosene, offers
the prospect of highly attractive weight and size

Fig.13
It should be noted that in the 20 to 1000 kW engine range, most kerosene capable engines are CI and therefore
necessarily heavy. Even a significantly de-rated kerosene fuelled SI Duke engine offers potential best in class
power density (kW/kg) when compared to typical compression ignition engines. Duke Engine's current plan is
to return to the Dynamometer in 2011 with a Duke engine specifically designed to operate on kerosene.
FLEX – FUEL AND VARIABLE COMPRESSION
It may be desirable to operate the same engine on a range of alternate fuels with limited "limp home" or fully
optimized function on each fuel. In an SI engine, the compression ratio is likely to be the largest single
compromising characteristic that limits the ability of a single engine to operate effectively on a range of fuels.
The ability to vary compression ratio should be recognized as a highly desirable feature in a flexible fuel SI
engine, especially where optimized performance on each fuel is sought. Variable compression ratio, though
desirable, is not easy to implement in a conventional engine.
However the Axial arrangement of the Duke engine lends itself to the addition of variable compression ratio
without adding significant size, weight or complexity
The relative ease of incorporating variable compression ratio is a major advantage of the Duke axial
engine layout, with detail design and associated patent protection in development.
3.7
Duke Engines Multiple Applications
As well as Automotive applications the Duke Engine lends itself well to Marine, Aircraft and
Generator/Utility Range Extender options. The output shaft, being 'geared down' to 5/6 of the piston
reciprocating speed, allows the 'engine-out' torque to be higher and maximum torque to be developed at
lower speeds. The Duke Engine is generally well suited to many applications of 40kW or greater.
MARINE
The axial arrangement of the Duke engine lends itself well to marine outboard (vertical shaft) and Inboard
(horizontal shaft) applications.

The maximum torque/power characteristics at low speed of the Duke engine are often desired in marine
applications and may allow for less gear ratio change, resulting in potentially smaller, lower-drag transmission
housings around the lower drive leg.
In general, the Duke engine would be best suited to marine applications of approx 50kW or greater, with the
low vibration from the Duke providing performance benefits in all marine applications. The Duke engine's
counter rotating cylinder group and crankshaft enable partial or complete cancellation of gyroscopic torque
reactions, offering another benefit to applications where high speed manoeuvrability is required.
OUTBOARD
Fig.14
The Duke engine in a vertical shaft application presents all the manifold, fuel and ignition system on its upper
face, allowing simple service access. With exhaust porting on the upper face of the engine an effective riser
feature is intrinsic, effectively preventing water entering the engine from the exhaust system. This eliminates
the need for a heavier external riser as found on traditional outboard engines.
The lower weight potential of a Duke engine is highly attractive to reduce both outboard weight and transom
loads. The narrower width engine of the Duke compared to conventional V configuration engines found in
larger outboards will enable tighter engine spacing with multiple outboard installations.
INBOARD
Fig.15

This combination of lighter weight, simple design and high engine torque enables a 4-stroke Duke engine to
possess some of the desirable characteristics and benefits traditionally associated with 2-stroke engines while
complying with 4-stroke legislative market requirements.
The service access items on the engine are concentrated on the front face of the engine in this application,
allowing convenient access even when engines are close coupled to the transom.
In a horizontal shaft installation, the Duke engine offers a very low profile, a low centre of gravity and
low weight that will improve the options for installing the engine under deck or seating. All of which offer
benefits to craft handling and performance.
AIRCRAFT
Low weight and small package size are obvious benefits in aircraft and a spark ignition Duke engine operating
on kerosene offers a development potential that will be appreciated by civil and military applications alike.
Fig.16
The cylindrical shape of the Duke engine lends itself well to installation in small cowlings with lower drag, and
the superior balance and vibration characteristics of the axial Duke engine will be appreciated in many
aerospace applications, leading to lower airframe vibration, fatigue and mount isolation requirements.
These characteristics combine to offer a prospect of a Duke reciprocating engine being a viable alternative to
some current smaller turbo shaft propulsion and auxiliary power unit applications.
Fig.17
Duke's counter-rotating cylinder group offers partial cancellation of gyroscopic torque reactions. The Duke
output shaft being intrinsically “geared down” to 5/6 of the piston reciprocating speed allows the engine out
torque to be higher and max power developed at lower speeds.
This combination of the Duke engine’s unique features would allow a Duke engine to produce a higher output
and turn a larger propeller before high tip speeds required the use of a gear box.
Once again the 'geared down' output shaft of the Duke delivers higher engine-out torque and maximum power is
developed at lower speeds is significant.

OTHER APPLICATIONS
These characteristics may be useful in applications where the required speed is fixed as with some AC
generators for example. The cylindrical package shape is similar to electrical generator configurations and
offers the opportunity of a compact and efficiently packaged overall machine.
The light weight of the Duke will be of particular benefit where generators or pumps are required to be air or
manually transportable, for example in Emergency services or military applications. And the potential to
operate on kerosene is highly desirable, something not widely available in standard smaller, lightweight
generators.
Fig.18
APUs are another application area where Duke technology can provide significant advantages.
3.8
The Ideal Range Extender
The Duke Engine lends itself well to Marine, Aircraft and Generator/Utility, Automotive and Hybrid
electric vehicle Range Extender Applications. The Duke output shaft, being intrinsically 'geared down' to
5/6 of the piston reciprocating speed, allows the 'engine-out' torque to be higher and maximum torque to
be developed at lower speeds.
The Duke Engine design consists of 3 or 5 conventional cylinders arranged axially. The cylinder group rotates
counter to crankshaft at 20% of crank speed (in the Duke 5 Cylinder arrangement) causing pistons to
reciprocate at 120% of crank speed. A near sinusoidal piston motion is achieved using a "Z" crank with single
inclined journal and a nutating body attached to all connecting rods. 4-stroke porting and valve function is
achieved using sliding seals between the low-speed rotating cylinder group and a monoplane ported surface.
Under its current design iteration the Duke Engine Range Extender concept consists of
• 5 x 250cc cylinders displacing 1500cc per 2 rotations of crankshaft.
• Near cylindrical shape 276mm x 255mm x 426mm
• Long-engine packing-crate envelope 30 litres

• Weight approx 41kg using conventional materials
• 56kW @ 4000 rpm / 70 kW@6000 rpm NVH Major NVH features of the Extender package are
• Near sinusoidal piston motion with full balance of primary forces
• Negligible secondary or tertiary imbalance
• 5 Cyl. Duke engine provides 3 combustion events per output shaft rotation – as conventional 6 cyl.
• Excellent NVH potential, may allow smaller displacement/higher speed engine to be used
• Compact combustion chamber with charge not exposed to hot exhaust valves is highly detonation resistant,
enabling practicable compression ratios of 12.5:1+ on regular Gasoline
Emissions
The Duke Engine features a low speed, mono-plane sliding seal arrangement with otherwise conventional
cylinders. Potential engine out emissions performance is estimated to be between Wankel and conventional
engines. Due to high detonation resistance and 3 runner exhaust manifold for 5 cylinders; The Duke engine
offers efficient full load operation at Lambda 1, and has a low heat loss rejection area pre-catalyst. The Duke
engine offers an after-treatment friendly prospect to address emissions requirements.
Fig.19 fig.20
Cost
There are many cost-saving features in the unique Duke Engines design. Just a few are:
• Low parts count on per-cylinder basis
• 5 Cylinder engine with only 3 injectors, 3 spark plugs and manifold connections
• The Duke is constructed using relatively conventional materials and manufacturing
Efficiency

The high compression ratio capable duke engine offers significant efficiency benefits.
An early, un-optimised 5 Cyl, 3.0 Litre prototype was successfully tested at Mahle UK. Results found that:
• Friction levels were comparable with conventional engines
• BSFC were comparable with modern conventional engines
• The 12.5:1 compressing ratio engine proved to be extremely detonation resistant with no detonation being
identified throughout full load spark sweep testing.
Overall
The Duke engine already exhibits excellent NVH potential and good package, weight and efficiency potential.
Licensing options are open and with development there is great potential for increased performance and
optimization to meet specific application requirements.
Fig.21
3.9
Light Aircraft Application
The Duke engine is the world’s only viable axial, 4 stroke, spark ignited piston engine. It is lightweight,
small, valveless, vibration-free, has very high power density, and runs on most fuels, including
kerosene/jet fuel. The Duke engine is a great fit for aerospace applications, including ultralight,
experimental and UAV platforms.
The Duke engine is in advanced stages of development, with prototype engines operational.
The 5 cylinder, 4-stroke internal combustion engine platform offers numerous benefits in aerospace
applications:
Duke Aircraft Engine #1 - 2.0 Ltr – 3300 rpm
Power: 103 hp @ 3300 rpm
Weight: 101 lbs (no gearbox req’d)
Size: Length: 17.3 in x Diameter: 11.6 in
Duke Aircraft Engine #2 - 2.0 Ltr – 6250 rpm
Power: 180 hp @ 6250 rpm
Weight: 101 lbs (+gearbox)
Size: Length: 17.3 in x Diameter: 11.6 in

• Aerodynamically friendly cylindrical shape, with output shaft on centre line.
• Installation in small cowlings with lower drag.
• Low weight.
• Small package size.
• Near perfect mechanical balance for very low vibration.
• Direct drive low-power or geared high-power options.
• High power density potential - over 0.7 hp/lb installed weight in direct drive option or over 1.0 hp/lb @ 2700 -
3300 rpm output shaft speed in geared option.
• Multi fuel options. Automotive gasoline with low octane requirements. Compatible with 100LL avgas.
• No cam drive train or valves.
• Low parts count.
• Simplicity of design – 3 injectors & 3 manifold connections for 5 cylinder engine.
• Multi-point spark ignition simply achieved.
• Partial cancellation of gyroscopic effects from slow speed counter rotation of cylinder group.
• Suitable for 50hp to 350+ hp
These characteristics combine to offer a prospect of a Duke reciprocating engine being a viable alternative to
some current smaller turbo shaft propulsion applications.
The Duke engine features many technological breakthroughs.
The Duke’s unique counter-rotating, almost vibration-free motion and the unique design methodology
employed address previous limitations in axial piston engines, especially power and speed.
This also results in partial cancellation of engine-based gyroscopic torque reactions, reducing loads on mounts
and structures.
With the output shaft being intrinsically “geared down” to 5/6 of the piston reciprocating speed, this allows the
engine-out torque to be higher with max power developed at lower speeds.
Fig.22
This combination of features allows it to produce a higher output and turn a larger propeller before high tip
speeds require the use of
a gear box.
The Duke engine delivers significant weight & size savings.
Compared to conventional IC engines with similar power, the Duke can be considerably lighter and up to 30%
smaller. Use of lightweight materials could further improve weight advantage.

The Duke engine has negligible 1st-order and 2nd-order vibrations.
The axial cylinder arrangement with near sinusoidal piston motion delivers near-perfect mechanical balance.
The superior balance and vibration characteristics of the axial Duke engine lead to lower airframe vibration,
fatigue and mount isolation requirements.
Cooling
Cooling is achieved with conventional water jackets around the cylinders and ported areas.
Seals around concentric flow passages allow the coolant to enter and leave the rotating cylinder group.
The coolant is then circulated in a conventional manner through radiators mounted on the airframe, using a
pump.
Fig.23
The Duke engine delivers high thermodynamic efficiency.
The absence of hot valves in the favourably-shaped combustion chamber allows high compression ratios for
efficient operation on low octane fuels.
Current engines operate on 91 octane gasoline detonation free at compression ratios above 12.5:1
The Duke engine offers complete fuel flexibility.
Development will allow operation on all appropriate fuels, including ethanol/methanol and blends, bio-
ethanol, LPG, CNG, hydrogen, kerosene and diesel. Spark ignition Duke engines are currently successfully
running on 91 octane gasoline and kerosene/jet-A1.
Fig.24
The Duke Engine is far less complex than traditional
IC engines.
The Duke Engine’s much lower part and component count (only 3 sets of spark plugs, injectors and ports for 5
cylinders with no valve train), coupled with ease of repair and maintenance and potentially lower production
costs, offer potential for savings in manufacturing and operation. While the Duke uses existing materials and

manufacturing processes in its construction, there is considerable scope for the use of light weight materials as
appropriate.
Duke Engines is committed to Research & Development, with further advances already under way.
The Duke engine is currently in its 5th generation with latest prototypes undergoing testing.
The Duke engine has wide IP protection.
Through out the development process, Duke Engines has filed many patent applications to protect key aspects
of its technology.
Duke Engines – International Testing
Throughout development the Duke Version 3 has been continuously tested at various national and
internationally recognised testing and dynamometer facilities.
Earlier this year the range of Duke engines was again tested in the US.
Please contact us if you are interested in seeing our engine.
DUKE CHALLENGES
All V3i gasoline and Jet A1 testing to date (March 2012) has been completed with a single set of prototype seals
which remain in good condition. These seals will be reassembled into an engine for further testing without
modification or repair.
Duke challenges in seal development are much less than in a 2-stroke or in the Wankel engine due to lower
sliding velocity and a flat monoplane sealing surface (Wankel has 3 seal faces, 1 curved, that meet at a corner,
seals). So far, our sliding seal challenges are proving to be modest in reality.
CHAPTER 4
4.1
DUKE ENGINE ENDORSEMENTS
OVERVIEW
Throughout its development and testing phases the Duke engine has received many endorsements from
eminently qualified engineers, scientists and experts in the field.
ENDORSEMENTS
4.2
CONCLUSIONS
• Part-load fuel economy is comparable with modern conventional engines …
• Full-load performance is comparable with modern conventional engines without performance enhancing
technologies such as cam phasing and switchable intake systems
• Motored engine friction falls within the range of current conventional engines.

• Exhaust temperature at part-load is high compared to conventional engines – this might prove to be an
advantage for catalyst light-off in automotive applications…
“ …no technical barriers to using the Duke engine in automotive applications.”
Mahle Powertrain Development Report, 2007/8
“The inventiveness and ingenuity in design and execution to get this far is very impressive. The engine has
several major advantages over conventional IC engines such as – power / weight ratio and fuel economy,
packaging size, smooth vibration free running with impressive throttle response, no valve train and half the
number of injectors and spark plugs. These advantages have the potential to make the engine extremely
desirable to the auto industry today.”
Geoff Martin, ex Engineering Manager Ford Motor Company NZ, 2008
“The Duke engine is continuing to show its initial promise. It already performs comparably to current engines,
without any refinement of detail in porting, timing, or combustion management. There is as yet no limit found
to prevent improvement in all of these areas.… The over-riding feature driving the Duke engine is its weight,
size, and simplicity advantage over conventional engines.”
Prof. Peter Squires, University of Canterbury, 2008
“… Mahle would be enthusiastic to work as a development partner with Duke on automotive and other market
commercialisation.”
Hugh Blaxill, Chief Engineer, R&D, MAHLEPowertrain Ltd., 2010
“…a rare example of a novel engine worthy of advancing tomarket…”
Dr. Mike Fry, Engine Development Expert, Principal Ngenious Ltd. UK,ex Cosworth Head of R&D, 2011
“..I still firmly believe in the ultimate success of the engine,it’s systems and the overall concept…”
Bob McMurray, CEO A1 RacingTeam, NZ, ex McLaren Formula 1
“.. it’s key advantages are weight and packaging;… it will also package very well in hybrid transmission
vehicles and with it’s light weight will not have such a serious disadvantage in rear mounted arrangement,, thus
opening up a range of design freedoms that are otherwise denied in the industry.……very attractive to the
aviation industry…, …real potential for commercial exploitation>’
Prof. J.N. Randle, Automotive Expert, ex Rover/Jaguar, Director Vehicle Engineering, responsible for
JaguarXJ6/12, Director/Prof. Automotive Engineering Centre,Univ. of Birmingham, Prof. for
Manufacturing Engineering, DeMontford Univ., 2006
“The engine (Duke, sic.) has some significant advantages over designs that are currently in the marketplace
including improvements in power density, vibration, knock resistance and component numbers. It also has the
potential to bring fuel efficiency benefits, design and integration benefits and cost of ownership benefits.”…
Alistair Hill, Knibb, Gormezano & Partners, 2008.
5.2
REFERENCES:-

Duke engine technology (redial engine)

Duke engine technology (redial engine)

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