After a successful meeting with Lotus Powertrain and a representative from Toyota Research Laboratories, I loaded the van up with the free piston engine, and brought it back to Lincoln, where it will be installed in one of the experimental test cells when we move into the new building.
The next stage in the development will be for Control Techniques to recommission the electrical drive and position controller for the rotary machine.
The free-piston engine in the laboratory ready for re-commissioning
This engine is absolutely unique, as it is able to function as a conventional single cylinder research engine, or as a free-piston engine by disconnecting the connecting rod from the crankshaft.
Presently the engine is set up in conventional operating mode, as a single cylinder research engine. It is novel in this operating mode, as the crankshaft is connected to a low inertia, high torque electrical servo-motor, which allows us to not only apply dynamic loads to the engine, but also control the shape and phase of piston trajectories, particularly through top-dead-centre.
This has allowed us to achieve the first dynamic examination of Quasi-Constant-Volume-Combustion, by reducing the piston velocity through the combustion phase of the cycle through top-dead-centre. This activity resulted in the paper
The next research steps over the forthcoming year will be the investigation of the thermodynamic cycle using advanced control techniques, none of which are achievable on any currently produced engine configurations. We will be reporting on the research outputs in due course.
Prof Stewart at Lotus Headquarters in Hethel, hoping they'll let him take the Evora around the test track
Many thanks must go to the Lotus team for fitting the new linear motor/generator which we designed and built. In particular to Jim Young, who has been responsible for most of the modifications to this engine, which have been in many cases outlandish and seemingly impossible. Well done Jim!
Staying over in Norwich tonight before the big event tomorrow, picking up the Free Piston Engine from Lotus Cars after its most recent modifications, fitting the new linear motor/generator.
I’m also meeting a representative from Toyota in Japan with Jamie Turner, Chief Engineer from Lotus, to discuss our free piston work.
I’m going to take the engine over to the ThinkTank in Lincoln tomorrow, where it will be stored in the interim until the move into an engine test cell in August.
Control Techniques, who supplied the electrical drives, will be re-commissioning the experimental rig.
Sandpits are an increasingly popular choice for the distribution of Research funding by RCUK. I have just been part of an EPSRC evaluation exercise on Sandpits, so I thought I would dig some photos out of the archive and give an idea of what goes on, which I hope is helpful to those unfamiliar to this process.
PIC1: Participants at the 'Low Carbon Airports' Sandpit putting together the mind map at the end of day 1
I’ll deal with the application process in another blog, as it requires a different approach to conventional grant applications. My experience is with EPSRC sandpits, which are held in country hotels with large function facilities.
PIC1 illustrates the state of play towards the end of day 1 of the EPSRC ‘LowCarbon Airports’ Sandpit which was held towards the end of 2008. At this point, we had checked in, completed some ice-breakers, and in groups had started to brainstorm the issues associated with the theme. The yellow cards on the floor are the outputs of this process which are now being moved around and coalescing into challenges (PIC2).
PIC2: Part of the mind map relating to environmental issues
The process is one of the most intensive and tiring experiences. Starting at 9.00, the activities run generally until 18.00, however that’s when the hard work really starts, with clusters working long into the night. Actually in some cases, all night!.
Be prepared to do a lot of presenting! The ideas, as they coalesce are repeatedly presented by their champions and honed by criticism (both positive and negative) from the floor. It’s at these points that clear projects and project groupings start to emerge (PIC3).
Who’s there?
PIC3: A project definition and grouping starting to emerge at the Sandpit
There are generally three groups of attendees:
Academics who are the focus of the Sandpit
Facilitators – a professional team which runs the Sandpit and guides the process through its stages to fruition
Stakeholders – Industry and commercial interest groups are represented to maintain the applicability of the outcomes
Interestingly, in the background of PIC3 is a poster which I put up with points which are highly salient golden rules for Sandpit participants on all sides:
Stakeholders – ‘suspend disbelief’ in impracticalities
Issues – problems rather than solutions
Academics – ‘forget’ initial preferences and objectives – think outside the box
PIC4: L-R Prof Qing-Chang Zhong, Prof Edmund Burke and Prof Paul Stewart present on 'Integrating and Automating Airport Operations' which was successfully funded
All of which is intended to facilitate the creative process. By day 3, a number of projects have started to emerge, with a core set of champions, loose ‘memberships’ and plenty of ‘floating voters’. Essentially, there is a fixed budget for each sandpit, and open competition for funding, so the process is both collaborative and highly competitive. In this case, there was a budget of £3.4M, with 10 strong contenders emerging….
Roger Gardner, Sandpit Director and Director of the Omega Partnership addresses a project presentation session
Now the strategic ‘haggling’ between individuals and groups begins, as the competition increases to produce credible,fundable projects, and also to maximise individual involvement. A word of caution here is credibility. There is no difference between this part of the process and any other proposal procedure. Not only is a well thought out project plan with credible partnerships an absolute necessity, but also the crucial aspects of adventure, risk and most importantly ‘risk mitigation strategies’.
Unique to this process is that funding is allocated on the final day of the Sandpit, so all potential projects must be fully costed, with finalised members, objectives and project plans.
Prof Paul Stewart presenting the costed version of 'Airport Energy Technologies Network' which was successfully funded
There is no limit to the number of projects which you can propose, or the number of projects in which you can be involved. However there is generally a strong steer from the Stakeholders as to the preferred projects and groupings as they develop. Finally, the projects are ranked in preferential order, and a steer is given as to what adjustments need to be made to costings on the individual projects.
Roger Gardner, Sandpit director, giving out the good and bad news
In this Sandpit, 10 projects were proposed, with 7 being funded to a total of £3.4M. Three of the projects are currently running here at the University of Lincoln in the School of Engineering.
Most importantly, 19 out of the 22 participants came away with something to show for all the effort, ranging from studentships up to PI of large multi-centre projects.
Winners and losers: 7 successful and 3 unsuccessful proposals
All in all a very positive experience on the whole. In particular, the sandpit sparked multi-disciplinary, inter university collaboration which has acted as gearing for subsequent collaborative projects. all that’s left to do after the event is to make sure you get your full proposal in through the JeS system in time!
You can find out more about the funded projects via the Airport Energy Technologies Network (AETN) which is hosted in the School of Engineering at the University of Lincoln:
Simon Wilson setting up the motor control system in the engine test cells
Simon Wilson was in one of my 4th year MEng project groups at Sheffield Uni, and stayed on to read for a PhD with me on Temperature Estimation for Permanent Magnet AC Motors. Simon received an Industrial CASE award from Rolls-Royce Derby for the duration of his study. He can be seen here setting up the DSpace controller which supervises data acquisition and control for the engine.
Simon has subsequently joined EA Technology at Capenhurst as a consultant on new renewables technology.
Ed Winward setting up the control desk Labview front end
Next up is Ed Winward, who was working for Professor Rui Chen at Loughborough University. Ed designed and implemented the entire front-end for the free piston project in Labview (see picture left) which allowed us to start experimentation in earnest.
The best tribute to his part in this project is a YouTube video he made which documents an early run of the Free-Piston Engine
Close up of the Free-Piston Engine, showing timing belt, cam boxes, cylinder head and combustion chamber
After delivery to the engine test cells at Loughborough University AAE dept., it took a significant amount of time to put together the control system instrumentation, and the control architectures necessary to run the engine under Labview, and DSpace.
This part of the story is the people behind developing this part of the project.
First up is Dr Ben Taylor, who at the time was one of my Post-Doctoral researchers at the University of Sheffield Department of Electronic and Electrical Engineering, and is currently a Research Fellow there in the Department of Automatic Control and Systems Engineering. Ben designed and built the 100kW four-quadrant power converter which in the early stages of the project drove the permanent magnet servo-motor attached to the end of the tethering crankshaft. This arrangement allowed us to make the initial development happen relatively safely, without the danger of losing control and blowing up the engine. Later developments are untethered from the crankshaft and truly ‘Free-Piston’
Dr Ben Taylor connecting the 3-phase cables from the power converter to the PMAC servo-motor
Ben also designed the control system for the servo-motor, based around a TI Digital Signal Processor (DSP) which allowed accurate, real-time control of the motor currents, and position/velocity control of the motor, interfaced to a DSpace real-time controller.
Ben subsequently moved on to work for myself and Prof Chris Bingham on a RDA funded project on intelligent heating controls and methods for domestic houses.
The power converter which Ben designed and built is now in use driving the linear electrical machine embedded in the engine, whilst the drive of the crankshaft servo-motor has been take over by a custom designed four-quadrant inverter designed and installed by Control Techniques
Stage 1 development of the free-piston engine: engine and power converter.
Dr Ben Taylor with the control/data acquisition system
