Demonstrating the Fuel Economy Benefit of Exhaust Energy Recovery

内燃机仍然是将液体燃料转化为有用功的最经济有效的装置。即使生物燃料越来越受欢迎，IC发动机才是实现其效益的实用设备。集成电路发动机的工作原理是确保新鲜空气进入发动机以支持燃烧过程。供气的过程要求以废气形式的燃烧产物被迅速除去，从而形成热废气流。正是这种热废气流提供了产生额外有用能量的潜力。从热废气中产生能量可以通过几种方式完成，并且已经尝试通过蒸汽循环和通过涡轮机进行额外膨胀。大多数方法往往会显著增加发动机的机械复杂性，并随之增加成本。热电（TE）装置利用所谓的塞贝克效应，使用不同的金属可以在冷热物体之间产生电位差。在发动机中，这种温差将在废气和外部空气温度之间产生。这是一个很大的温差，为有效的能量转换提供了潜力。热力学理论表明，使用50kW的乘用车发动机，有可能在9-12 kW范围内再生能源。使用最好的现代热电材料，只能达到0.5-1千瓦，但这已经足够考虑，例如，用这样的热电装置代替汽车交流发电机。热电装置是固态的，没有活动部件，可能比迄今为止考虑的其他方法更耐用。TE方法成功应用的主要挑战是材料的质量。目前，散装物料的输送效率较低。新材料提供了巨大的潜力，但目前尚不清楚，在有一个实际的建议之前，需要多少额外的性能的材料。该项目的主要目的是利用Skutterudites材料展示最佳的热电性能，这种材料在该应用中显示出巨大的前景。正确理解并组装成模块，这些材料可以产生与汽车交流发电机竞争的TE性能。这些模块将在台架上进行测试，然后基于计算机的模型将与实际发动机一起实时使用，以预测整个发动机系统的燃油经济性。模型将被调整以包括假设的材料特性。调查的目的是确定一组材料的性质，这将给一个强大的系统性能。拟议的工作将使用一种被称为组件在环的技术，表明一台真正的发动机正在发动机测试实验室中使用。同时，TE设备被表示为一个模型，该模型以与真实设备的物理行为相同的速率在快速计算机上运行。它的输出将反馈到发动机系统，以表示产生的电流。闭环元件是一种新兴的技术，我们提出这种新颖的应用作为次要的研究目标。有了两组结果：一组拟议的材料特性和一种可行的研究方法，该项目将为材料的详细调查奠定基础，其结果将成为一种能够实际应用的设备。

The internal combustion (IC) engine remains the most cost effective device for converting liquid fuels to useful work. Even as bio-fuels become more popular, it is the IC engine that is the practical device for realising their benefits. The IC engine works by ensuring a good flow of fresh air into the engine to support the combustion process. The process of supplying air requires that the products of combustion in the form of exhaust gas are removed quickly creating a hot exhaust gas stream.It is this hot exhaust stream that offers the potential for generating additional useful energy. Generating energy from hot exhaust gas can be done in several ways and attempts have been made with steam cycles and with additional expansion through a turbine. Most methods tend to significantly increase the mechanical complexity of the engine and with it the cost.Thermo-electric (TE) devices use the so called Seebeck effect where using dissimilar metals a potential difference can be created between hot and cold objects. In an engine that temperature difference will be created between the exhaust gases and the external air temperature. This is a large temperature difference and offers the potential for efficient energy conversion. Thermodynamic theory suggests that with a 50kW passenger car engine, there is the potential to regenerate energy in the range 9-12 kW. With the best of modern thermo-electric materials only 0.5-1 kW could be achieved, but this is already enough to consider, for example, replacing the vehicle alternator with a such a thermo-electric device. A thermo-electric device is solid state, with no moving parts and is likely to be more durable than the other methods that have been considered so far.The primary challenge for the successful application of TE methods is the quality of materials. At present, bulk materials deliver a low efficiency. Newer materials offer a great deal of potential, but it is unclear how much extra performance is needed from materials before there is a practical proposition. The primary aim of this project is to demonstrate the best thermo-electric performance using the class of materials known as Skutterudites which are showing great promise in this application. Properly understood and assembled into modules, these materials can produce TE performance competitive with a vehicle alternator. The modules will be tested on the bench then computer based models representing this performance will be used in real time alongside a practical engine to predict the fuel economy of the whole engine system. The model will be adjusted to include hypothetical material properties. The investigation will be directed to identify the set of material properties that will give a strong system performance. The proposed work will use a technique known as component-in-the-loop, signifying that a real engine is in use in an engine test laboratory. At the same time the TE device is represented as a model which is run on a fast computer at the same rate as the physical behaviour of a real device. Its output will be fed back to the engine system to represent the electrical current produced. Component in the loop is an emerging technique and we are proposing this novel application as a secondary research goal.With the two sets of results: a set of proposed material properties and a viable research methodology, this project will set the scene for a detailed investigation into materials whose result will be a device capable of practical application.