Oilless Piston Engines

点击翻译按钮获取中文摘要

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.