Towards In-Combustion-Event Feedback (ICEF) Control by Laser Ignition

The project seeks to explore the science of laser ignition (LI) based control & sensing of combustion, leading towards In-Combustion-Event Feedback (ICEF) control in future internal combustion (IC) engines. The main objectives are to pursue optimisation of LI & sensing for next generation engine configurations, to provide knowledge to extend the stratified GDI combustion envelope by cycle-to-cycle variation reduction, to enhance fuel efficiency by up to 20% & progress towards large-scale engine NOX & HC emissions reduction. The work will explore dynamically varying temporal & spatial multi-point LI, rapid real-time optical sensing of combustion signatures and robust feedback control strategies for multi-point ICEF. It is widely accepted that the IC engine will continue to be the main vehicle power plant over the next 10-15 years, before significant displacement by other technologies (such as fuel cell based plant) takes place. To meet environmental legislation requirements, automotive manufactures continue to address two critical aspects of engine performance: fuel economy & exhaust gas emissions. New engines are becoming increasingly complex, with advanced combustion mechanisms that burn an increasing range of fuels to meet future goals on performance, fuel economy and emissions. In the spark-ignition (SI) engine, the spark plug has remained largely unchanged since its invention and limits the potential for improving efficiency due to its poor ability to ignite highly dilute air-fuel mixtures. Also vital to optimising engine performance is the sensing & diagnostics for high speed feedback control, but accurate real-time in-cylinder sensing is currently prohibitively expensive. LI offers several potential solutions, including the ability to ignite highly dilute air-fuel mixtures. Due to recent laser technology advances, the range of combustion control parameters can now be widened to include laser wavelength, pulse duration, spatial & temporal optical energy distribution, single & multiple ignition events. The opportunity now exists to explore how the dynamic selection of these variables can be optimised for more efficient and cleaner combustion over the widest range of engine operating conditions. The holistic systems approach will include making use of a self-cleaned optical pathway for both LI & feedback sensing purposes, to allow information-rich monitoring and control of combustion to be explored. An extensive programme is needed to establish basic engineering science for highly optimised combustion control by LI to suit specific engine configurations, operating conditions and fuel types. The key research hypothesis is that LI is a viable route to active feedback control of combustion, both cycle-by-cycle & ultimately within the combustion event, by multi-point / event actuation & delay-free self-cleaning laser optic virtual sensing. As well as progress towards the goal of full ICEF control, it will provide shorter term exploitation potential for in cycle-by-cycle combustion feedback control. The research methods to be adopted comprise novel work in: a/ the study of LI mechanisms for combustion control by high-speed ICEF, derived from laser wavelength tuning & spatially & temporally varied energy delivery in multiple foci to suit injection mode, absorption & combustion properties of fuel mixtures; b/ simultaneous use of a self-cleaned optical pathway for real-time in-event light signature capture from LI; c/ the use of sensor data & LI mechanisms for robust optimised ICEF control; d/the use of SLMs as a means to multipoint LI; e/ the optimisation of combustion control using Direct Numerical Simulation (DNS) studies. Use of the team's existing engine control facilities & liaison with FMC will allow study of rapid feedback control & its associated computer control issues, conducted through instrumented powertrain control experiments, with control strategies optimised via computational combustion research.

The principal beneficiaries of the research will be the academic and industrial partners of the project. The Laser Group and Powertrain Engineering Group in the School of Engineering at the University of Liverpool (UoL) are currently partnered on laser ignition (LI) research together with Ford Motor Company (FMC). FMC is a global developer and manufacturer of automotive vehicles and has leading internal combustion (IC) engine and associated powertrain technology development at its sites in the UK (Dunton), Germany and the United States. External industry beneficiaries will include, in powertrain engineering, a number of existing UK and Europe based developers of IC engines and related components, sub-systems and test equipment. In photonics, several UK and international laser manufacturers are currently developing solid state pulsed lasers as part of their product range. UK laser systems integrators have expertise in combining laser and optics technology with high precision machinery and computer control. Many leading developers of laser optics for delivery, modulation and sensing are currently collaborating with the Laser Group on materials processing applications. Further potential beneficiaries exist in the powertrain technology value chain. External academic beneficiaries will include UK research groups currently researching IC engine combustion and fuel systems including those at Loughborough University (led by Prof R Stobart), University of Nottingham (led by Prof P Shayler) and University College London (Prof N Ladommatos et al). Many international groups will benefit from dissemination of the research into the wider academic community, including the MIT Sloan Automotive Laboratory (led by Prof J Heywood) in the US, which is supported by FMC.How they will benefit from this research:The LI research team at the UoL will benefit from the opportunity to pursue new research in combustion control, enabled by the proposed project funds to enhance and make full use of the experimental facilities currently established with the support of FMC, together with the research staff and student resource. LI is an interesting research area with potential for interdisciplinary study and will lead to several high quality academic publications. The project will establish new research in laser applications, through the use of specially modulated pulsed lasers to explore laser ignition mechanisms and optical sensing for combustion control. FMC will benefit from access to a new pool of knowledge aimed at controlled combustion by LI, for competitive advantage by improved engine performance and emissions. Both parties would benefit from any successful joint patent applications, to be exploited through future licensing and industrial scaling projects. The successful outcome of the project will result in a significant global market for R&D and production level LI systems in the future, together with associated laser device and optics. Externally, the project will benefit the powertrain engineering sector by informing their work on future design of engines and associated components and sub-systems, including feedback control through sensor development and computer control strategies. Laser source and system developers will benefit from the application of high energy pulsed lasers in a new engineering research area and gain knowledge of the future capabilities required for their products. Laser system integrators will be well-placed to leverage knowledge gained from the research and translate this into prototype LI system development in the future. The UK will then have capability to build LI systems, through industrial scaling and device miniaturization. The project, if successful, will have significant socio-economic impact for the wider community, including: lower fuel consumption and reduced noxious emissions in IC engines; helping UK government to reduce/meet UK carbon footprint targets; job creation in a range of UK engineering sectors.