Oilless Piston Engines

活塞发动机中的润滑油保护接触部件，但导致碳氢化合物排放，催化剂中毒，频繁维护和主要热损失，因为衬套必须保持足够冷以防止过度油耗。许多作者讨论了解决这个问题的必要性，特别是在20世纪80年代和90年代开发所谓的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理想的，因为它们将实现低排放和高效率。以前不成功的尝试清楚地表明，要实现这一技术突破，仍然需要解决一些根本问题。活塞的无接触密封似乎是一个很有前途的选择，当结合到一个低压回热热力循环。这个发现补助金的目标是调查关键的多尺度的挑战，必须解决之前，一个持久的无油发动机的发展。该研究计划的创新方法是基于扭转传统思维。代替设计密封环以适应发动机配置约束，所提出的方法包括围绕关键密封系统重新思考发动机。这将通过以下步骤实现：（1）重新考虑热力学循环以降低汽缸压力，并因此降低泄漏，同时通过包括回热器来保持高效率，（2）研究活塞-衬套界面的流体动力学行为以产生升力，以便在密封燃烧室的同时避免界面处的任何接触，（3）通过使用高温陶瓷和适应的先进几何形状，研究活塞与衬套相适应的结构和材料;（4）研究消除活塞侧向载荷的传动机构。该计划的最后一个里程碑是提出一种无油发动机概念，该概念将通过建模、模拟和实验来优化，以实现高效率和高耐用性。最终，该计划将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，增加了发动机寿命，允许减少热损失，减少发动机排放，并允许实质上减小后处理系统的尺寸。这将降低发电的资本和运营成本，从而提高加拿大工业的竞争力，同时减少加拿大的环境足迹。该计划将培训5名高素质人员（HQP），并将产生新的知识，这将有助于清洁能源和运输部门。

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.