Oilless Piston Engines

活塞式发动机中的润滑油保护了接触部件，但会导致碳氢化合物排放、催化剂中毒、频繁维护和重大热损失，因为衬套必须保持足够的温度以防止过度消耗机油。解决这个问题的必要性已经被许多作者讨论过，特别是在20世纪80年代和90年代开发所谓绝热发动机的计划期间。然而，从环境角度来看，无油发动机仍然是非常可取的，因为它们将实现低排放和高效率。之前失败的尝试清楚地表明，要实现这一技术突破，仍需解决根本问题。活塞的无接触密封在与低压恢复热力循环相结合时似乎是一种很有前途的选择。*这项发现基金的目标是研究在开发耐用的无油发动机之前必须解决的关键的多尺度挑战。研究方案的创新方法是在扭转传统思维的基础上进行的。所提出的方法不是设计密封圈来适应发动机的结构约束，而是围绕关键密封系统重新考虑发动机。这将通过以下步骤实现：(1)重新考虑热力学循环，以降低气缸压力，从而降低泄漏，同时通过包括再生器保持高效率，(2)研究活塞-气缸套界面的流体动力学行为，以产生升力，以避免在密封燃烧室时在界面处发生任何接触，(3)研究活塞的结构和材料，以使其与气缸套保持一致，通过使用高温陶瓷和采用先进的几何形状，以及(4)研究传动机构，以消除活塞侧负荷。该计划的最后一个里程碑是提出一种无油发动机的概念，该概念将经过优化，以实现建模、模拟和实验所支持的高效率和高耐用性。*最终，该计划可能通过打破发动机设计中最大的限制之一来改变活塞发动机。去除润滑油消除了维护的需要，延长了发动机寿命，减少了热损失，减少了发动机排放，并大幅减小了后处理系统的尺寸。这将转化为发电资本和运营成本的降低，从而提高加拿大的工业竞争力，同时减少加拿大的环境足迹。该计划将培训5名高素质人才(HQP)，并将产生有助于清洁能源和交通行业的新知识。

Lubricating oil in piston engines protects the contacting parts, but leads to hydrocarbon emissions, catalyst poisoning, frequent maintenance, and major heat losses as the liner must be kept cool enough to prevent excessive oil consumption. The need to address this problem has been discussed by many authors, especially during the programs to develop the so-called adiabatic engines in the 1980s and 1990s. However, oilless engines remains highly desirable from an environmental perspective as they would achieve low emissions and high efficiencies. Previous unsuccessful attempts clearly indicates that fundamental issues still have to be resolved to achieve this technological breakthrough. Contact-free sealing of the piston appears to be a promising option when combined to a low-pressure recuperated thermodynamic cycle.***The goal of this Discovery Grant is to investigate key multiscale challenges that must be addressed previous to the development of a durable oilless engine. The innovative approach of the research program is based on reversing traditional thinking. Instead of designing the sealing rings to adapt to engine configuration constraints, the proposed approach consists of rethinking the engine around the critical sealing system. This will be achieved through the following steps: (1) rethink the thermodynamic cycle to lower the cylinder pressure, and thus leakage, while keeping a high efficiency by including a regenerator, (2) study the fluid dynamics behavior of the piston-liner interface to generate lift in order to avoid any contact at the interface while sealing the combustion chamber, (3) study the structure and materials for the piston to conform to the liner by using high-temperature ceramics and adapted advanced geometries, and (4) study the transmission mechanisms to eliminate piston side loads. The final milestone of the program is to propose an oilless engine concept that will be optimized to achieve high efficiencies and high durability supported by modeling, simulations, and experiments.***Ultimately, this program could transform piston engines by shattering one of the greatest constraint in the design of engines. Removing lubricating oil eliminates the need for maintenance, increases engine life, allows reducing heat losses, reduces engine emissions, and allow decreasing substantially the size of the after treatment systems. This would translate in decreased capital and operational costs of power generation which could boost Canadian industry competitiveness while reducing Canada environmental footprint. This program will train 5 Highly Qualified Personel (HQPs) and will generate new knowledge that will contribute to the clean energy and transportation sectors.