A 60% reduction in diesel use: the impact of optical diagnostics on dual-fuel engines
Submitting InstitutionLoughborough University
Unit of AssessmentAeronautical, Mechanical, Chemical and Manufacturing Engineering
Summary Impact TypeTechnological
Research Subject Area(s)
Engineering: Automotive Engineering, Mechanical Engineering, Interdisciplinary Engineering
Summary of the impact
Loughborough University's (LU) research collaboration with The Hardstaff
Group has resulted in a commercial Oil-Ignition-Gas-Injection system
(OIGI®), which substitutes natural gas for Diesel oil in heavy goods
vehicles. Using optical diagnostics OIGI® was redesigned, increasing
average substitution rates from 45% to 60%. The economic impact for
Hardstaff was a fuel saving of £406k per annum. The research allowed
Hardstaff to create new business with Mercedes-Benz in the UK and Volvo in
Sweden. OIGI® reduces CO2 by up to 15%, harmful nitrogen oxides
and particulate emissions by 30%. The research also demonstrated, for the
first time, dual fuel technology in small, high-speed diesel engines,
paving the way for its application in passenger cars.
Dr Andrew Clarke and Professor Graham Hargrave (joined LU in 1999 and
1996 respectively) have made detailed studies of dual-fuel technology
(natural gas and Diesel) and working with The Hardstaff Group, have
developed a robust and flexible dual fuel technology.
In 2001 work on dual fuel technology was first addressed by Dr Andrew
Clarke and became the subject of Dr Jill Stewart's PhD thesis "Combustion
Diagnostics of a Dual Fuel Engine: An Experimental and Theoretical Study"
(LU 2005) [G3.1]. This study concerned theoretical predictions and
experimental measurements to find the performance/emissions
characteristics for different gases. The work was published in the
proceedings of SAE [3.1] and subsequently as an invited
paper in a special issue on alternative fuels in the IMechE Journal of
Automobile Engineering [3.2]. In a parallel effort, dual fuel
technology was being investigated by the Nottingham based Hardstaff Group
to retrofit to their fleet of 100 vehicles.
2006 saw the first consultancy project between Loughborough and the
Hardstaff Group. Hargrave initiated a series of tests using optical
diagnostics to investigate key process parameters. Particle image
velocimetry (PIV), a technique pioneered by the Loughborough Optical
Engineering Research Group, was used to characterise gas injectors to
measure flow velocity and laser sheet imaging measured the degree of
mixing prior to combustion. The short pulse Diesel injection (essential
for dual fuel mode) was characterised using a novel liquid injection
set-up and high-speed video analysis.
In 2008 this research, together with the theory developed by Stewart and
Clarke, was exploited in a new Oil-Ignition-Gas-Injection (OIGI®) system
that, by way of an innovative control system that worked alongside the
vehicle's electronic control unit, could be exploited in a wider range of
vehicles including Mercedes Benz Actros trucks that were then being
introduced to the Hardstaff fleet. The Hardstaff Group funded a further
PhD — "Modelling Compression Ignition Engines", Dr. Steve Johnson,
Loughborough University (2008-2011) [G3.2] — to continue the
application of optical diagnostics and to produce a multiple zone
combustion model to forecast the performance over a range of operating
In 2009 East Midlands Development Agency (via its Transport iNet) awarded
a development grant to the Hardstaff Group/Loughborough University to
build a full-scale test facility for the production of dual fuel power
systems [G3.3]. This joint facility has been used to establish
phenomenological models of dual fuel combustion and to further optimise
the process [3.3, 3.4, 3.5]. The new facility has three dedicated
test engineers and this has dramatically speeded-up dual-fuel engine
From 2007 to 2010, the collaboration extended to the development of
predictive models for flame propagation in premixed gaseous mixtures with
varying gas composition, investigating methane from biogas sources
containing hydrogen. Experimental measurement of flame propagation rates
in turbulent premixed methane/hydrogen/air mixtures was conducted at
Loughborough, providing data for reacting LES model development and
validation in collaboration with Naples University [3.6].
References to the research
3.1 Patterson, J., Clarke, A. and Chen, R.,"Experimental study of the
performance and emissions characteristics of a small diesel gen-set
operating in dual-fuel mode with three different primary fuels", SAE Paper
No 2006-01-0050, New Diesel Engines and Components and CI Engine
Performance for Use with Alternative Fuels, SP-2014, Society of
Automotive Engineers, Inc., USA, Proceedings of the SAE 2006 World
Congress & Exposition, Detroit, Michigan, USA, April 2006, pp 1-11,
ISBN 0-7680-1749-1. DOI: 10.4271/2006-01-0050, Peer-reviewed
3.2 Stewart, J., Clarke, A. and Chen, R.,"An experimental study of
the dual-fuel performance of a small compression ignition Diesel engine
operating with three gaseous fuels", Proceedings of the
Institution of Mechanical Engineers, Part D: Journal of
Automobile Engineering, 221(8), 2007, pp 943-956, ISSN
0954-4070. DOI: 10.1243/09544070JAUTO458, Impact factor 0.583.
3.3 Clarke, A. and Hargrave, G.K.,"Measurements of laminar premixed
methane-air flame thickness at ambient conditions", Proceedings of
the Institution of Mechanical Engineers, Part C Journal of Mechanical
Engineering Science, 223(C8), 2009, pp 1969-1973, ISSN 0954-4062.
DOI: 10.1243/09544062JMES1259, Impact factor 0.633.
3.4 Stewart, J. and Clarke, A.,"A three-zone heat-release rate model
for dual-fuel combustion", Proceedings of the Institution of
Mechanical Engineers Part C: Journal of Mechanical Engineering
Science, 224(11), 2010, pp 2423-2434, ISSN 0954-4062. DOI:
10.1243/09544062JMES1955, Impact factor 0.633.
3.5 Johnson S., Clarke A., Fletcher T., and Hyland D., "A
phenomenological approach to dual fuel combustion modelling" Proceedings
of the ASME 2012 Internal Combustion Engine Division Fall Technical
Conference ICEF 2012 September 2012, Vancouver, BC, Canada. Peer-reviewed
3.6 Di Sarli, V., Di Benedetto, A., Long, E.J. and Hargrave, G. K.,
"Time-resolved particle image velocimetry of dynamic interactions
between hydrogen-enriched methane/air premixed flames and toroidal
vortex structures," Int. J of Hydrogen Energy, 2012, 37, pp16201-16213,
ISSN: 0360-3199, Impact factor 3.548.
Grants and contracts:
G3.1 2001-04: Studentship (Jill Stewart) "Combustion Diagnostics of a
Dual Fuel Engine: An Experimental and Theoretical Study"
EPSRC/Lister-Petter, £47k Dr Andrew Clarke (PI).
G3.2 2008-10: Studentship (Steve Johnson) "Modelling of Duel Fuel
Compression Ignition Engines" £90k, The Hardstaff Group, Dr Andrew Clarke
G3.3 2009-10: Development Grant "Demonstration Project Force — Future
On-Road CI Engines" £694k Project EMX06157 East Midlands Development
Agency, Dr Andrew Clarke (PI), Prof. Graham Hargrave
G3.4 2010-12: Research Grant "High Speed Dual Fuel Direct Injection
Engines with Advanced EGR and Injection Strategies to Reduce Carbon
Dioxide Emissions" £148k TSB/EPSRC, Dr Andrew Clarke (PI), Prof. Graham
The turbulent flame propagation research, providing the under-pinning
validation data for LES model development for gas engine combustion
prediction [3.6], led to on-going collaborations with Dr. V. Di Sarli at
Naples University and Prof. H. Kawanabe at Kyoto University [L1].
The research provided a unique data-set for methane and methane/hydrogen
combustion that has been used for fundamental model development [L2].
L1. Invited Lecture, Prof. G. K. Hargrave — University of Kyoto, "Optical
diagnostics for natural gas engine research," 2010.
L2. Dr. E. Long, "Turbulent premixed flame propagation in methane/air
mixtures," won best paper in Institute of Physics Young Researchers
Details of the impact
In this section we present evidence that the research cited in s2 and s3
has had the following three major impacts:
- economic benefit (reduced running costs) in the haulage industry
- environmental benefit (reduced emissions) nationally and
- change in approach to new fuel systems in industrial production.
Impact 1: Economic benefits to haulage sector
The optical diagnostics applied by Hargrave in the period from 2006-2010
and the theory developed by Clarke from 2001 [3.3, 3.4] allowed
Hardstaff to introduce their innovative new Oil-Ignition-Gas-Injection
(OIGI®) system in 2008. The research allowed the average Diesel
substitution rate (by energy) to be increased from about 45% to a natural
gas content of about 60%. The immediate impact of this was reduced running
costs for the Hardstaff haulage business that operates a fleet of more
than 100 heavy goods vehicles in the UK. At current pricing the increased
substitution rate offers a saving of £406k p.a. and compared to a similar
sized fleet operating on 100% Diesel fuel a saving of £1.6M p.a. [5.1].
The application of the theory developed by Clarke [3.3, 3.4] has
allowed the OIGI® system to be reconfigured for other engines and has
reduced the experimental time necessary to re-map the control system from
around two weeks to one day [5.1]. This has created a further
revenue stream. The Hardstaff Group is now an approved Mercedes-Benz
Dealer that supplies the OIGI® system as an approved retro-fit or OEM
system on all Axor and Actros long haul trucks in the UK. In 2012 this
business was worth approximately £2.8M and with current orders is expected
to double in 2013 [5.1]. In addition a Scandinavian subsidiary,
Hardstaff AB, located in Göteborg Sweden, was opened in 2010 to provide
OIGI® systems for Volvo FL and FE trucks. This business was worth
approximately £1.3M in 2013 [5.1].
Impact 2: Environmental benefits
The precise control that is afforded by the OIGI® system means that it can
be optimised to reduce emissions and adjusted to run on carbon neutral
biogas and other biofuels [5.1, 5.2]. The £694k
Hardstaff/Loughborough University full scale test facility funded by East
Midlands Development Agency was commissioned in 2009 and allowed the
environmental impact of dual fuel technology to be assessed particularly
under transient loads. Relative to a comparable Diesel engine, dual fuel
offers a 15% reduction in carbon dioxide and at least 30% reduction in
harmful nitrogen oxides, smoke and particulate emissions [5.1].
The environmental impact of dual fuel technology is considerable in the
UK, Europe and beyond and resulted in Hardstaff and Loughborough
University winning the prestigious Lord Stafford Award in 2010 for
"Innovation for Sustainability" [5.3] and Hardstaff Group being
runner-up in the industry's Low Carbon Champions Awards hosted by the
Institute of Mechanical Engineers [5.4].
Impact 3: Changing approaches in industry
As a result of the work of Johnson and Clarke and work conducted under the
TSB/EPSRC Grant "High Speed Dual Fuel Direct Injection Engines with
Advanced EGR and Injection Strategies to Reduce Carbon Dioxide Emissions"
a state-of-the-art computer model of the dual fuel combustion process has
been developed [G3.4]. It has been shown that with multiple Diesel
injection events, it is possible to increase the substitution rates in
small, high speed engines. This work paves the way for the exploitation of
dual fuel systems in passenger cars and small/medium commercial vehicles.
Sources to corroborate the impact
The following sources can be made available at request:
5.1 Letter from Hardstaff
5.2 The Hardstaff dual fuel technology is detailed in the company
5.3 Hardstaff Group and Loughborough University winner of the Lord
Stafford Award 2010 for "Innovation for Sustainability", http://www.hardstaffgroup.co.uk/site/awards/lordstaffordaward
5.4 Hardstaff Group runner-up in the Low Carbon Heavy Duty Vehicle
Manufacturer of the Year 2011, http://www.lowcvp.org.uk/lowcarbonchampions/results.asp