Advanced fuel and propulsion technologies for low-carbon future transport

今天，世界上80%以上的能源是由燃烧化石燃料的热电系统提供的。根据2019年BP能源展望报告，由于液体燃料具有更高的能源密度和广泛的供应基础设施，至少在未来几十年内，液体燃料仍将是交通运输的主要能源。为了使运输部门脱碳，政府间气候变化专门委员会强调了生物燃料以及氢和电子燃料等其他替代燃料的重要作用，在某些情况下，到2050年可提供50%以上的运输能源。可再生运输燃料的重要性也得到了英国政府2018年4月发布的修订后的可再生运输燃料义务的承认，该义务规定了到2032年将生物燃料的目标数量增加到常规泵送燃料的12.4%。在实践中，有几个障碍阻碍了低碳和零碳燃料的应用。作为一种零碳燃料，氢气可以被生产出来，并作为太阳能和风电场的有效储能和能源载体。但是，由于建立多种燃料供应基础设施和车载加油系统的复杂性和高昂的成本，它的存储和运输仍然是在发动机中广泛使用的一个重大挑战。虽然低碳可再生液体燃料，如由氢气和二氧化碳生产的乙醇和甲醇，可以与现有的燃料供应系统一起使用，但其能量密度明显较低，约为汽油/柴油的一半，不利于直接应用于现有发动机的各种应用(如汽车、飞行汽车、轻型飞机、重型车辆等)。对功率密度要求很高。在推动电气化以满足碳排放减少的同时，创新开发先进的混合动力和发动机动力总成，为未来的低碳交通提供更多选择是至关重要的。本研究旨在对涵盖燃料和推进系统的三项创新技术进行开创性研究：纳米气泡燃料和纳米聚变系统、燃料柔性BUSDICE和DFFEG系统。无论是孤立的还是混合的技术，都有可能在解决运输部门脱碳的挑战方面做出重大贡献。首先，我将探索如何将纳米气泡燃料(纳米燃料)的概念用作可再生气体燃料的载体，以纳米气泡的形式存在于液体燃料中。该技术的实施只需对燃烧发动机进行最小限度的新开发，因此有可能通过提高发动机效率和增加可再生能源的使用，对减少二氧化碳排放产生立竿见影的影响。其次，将系统研究一种新型的二冲程燃料柔性BUSDICE(Boost Uniflow Screvened Direct Inputation Engine)概念，该概念将涉及开发工作，以适应传统化石燃料和低碳可再生燃料(如乙醇和甲醇)的使用，同时实现优越的动力性能和超低排放。最后，基于开发的BUSDICE概念，将通过集成线性发电机和气体弹簧室来进一步开发专用燃料柔性发动机发电机(DeFFEG)，从而为包括汽车、航空和船舶工业在内的一系列应用实现先进的电气化和混合动力。这项研究不仅具有带来新的和富有成效的学术研究领域的巨大潜力，而且将有助于开发下一代燃料和推进技术，以实现政府关于未来低碳和零碳交通的雄心勃勃的目标。

More than 80% of world energy today is provided by thermal power systems through combustion of fossil fuels. Because of their higher energy density and the extensive infrastructure for their supply, liquid fuels will remain the dominant energy source for transport for at least next few decades according to 2019 BP Energy Outlook report. In order to decarbonise the transport sector, the Intergovernmental Panel on Climate Change highlights the important role that biofuels and other alternative fuels such as hydrogen and e-fuels could, in some scenarios provide over 50% of transport energy by 2050. The importance of the renewable transport fuel is also recognized by the UK Government's revised Renewable Transport Fuel Obligation published in April 2018 which sets out the targeted amount of biofuels to 12.4% to be added to regular pump fuel by 2032.In practice, there are several obstacles which hinder the application of low-carbon and zero-carbon fuels. As a zero-carbon fuel, hydrogen can be produced and used as an effective energy storage and energy carrier at solar and wind farms. But its storage and transport remain a significant challenge for its wider usage in engines due to the complexity and substantial cost of setting up multiple fuel supply infrastructure and on-board fuelling systems. Although the low-carbon renewable liquid fuels, such as ethanol and methanol produced from hydrogen and CO2, can be used with the existing fuel supply systems, the significantly lower energy density, which is about half of that of gasoline/diesel, makes them unfavourable to be directly applied in the existing engines for various applications (e.g. automotive, flying cars, light aircraft, heavy duty vehicles, etc.) with high requirements on power density. Whilst there is a drive to move towards electrification to meet the reduction of the carbon emissions, it is vital to innovate developments in advanced hybrid electrical and engine powertrain to provide additional options for future low-carbon transport.This research aims to carry out ground-breaking research on three innovative technologies covering both fuels and propulsion systems: nanobubble fuels and Nano-FUGEN system, fuel-flexible BUSDICE and DeFFEG system. The technologies either in isolation or as a hybrid have the potential to make a major contribution in addressing the challenge of decarbonising the transport sector.At first, I will explore how the nanobubble fuel (nano-fuel) concept can be used as a carrier for renewable gas fuels in liquid fuels in the form of nanobubbles. The technology can be implemented with minimal new development to the combustions engines and hence has the potential to make immediate impact on reducing CO2 emissions through better engine efficiency and increased usage of renewable energy. Secondly, a novel 2-stroke fuel-flexible BUSDICE (Boosted Uniflow Scavenged Direct Injection Combustion Engine) concept will be systematically researched and will involve development work for adapting to be used with both conventional fossil fuels and low-carbon renewable fuels (e.g. ethanol and methanol) and simultaneously achieve superior power performance and ultra-low emissions. At last, based on the developed BUSDICE concept, a Dedicated Fuel-Flexible Engine Generator (DeFFEG) will be further developed by integrating a linear generator and a gas spring chamber, therefore enabling advanced electrification and hybridisation for a range of applications, including automotive, aviation and marine industries.Overall, the proposed project is an ambitious and innovative study on the fundamentals and applications of the proposed fuel and propulsion technologies. The research not only has great potential to bring about new and fruitful academic research areas, but also will help to develop next-generation fuel and propulsion technologies towards meeting Government ambitions targets for the future low-carbon and zero-carbon transport.