Patent CA-2731299-A1 (CA)
Inventor: FERNANDES LUIZ CLAUDIO VIEIRA
IPC: F16J15/40
Filed: 2011-02-09
Abstract: This invention mainly consists of a geometric novel system that can be mainly used as 1) an efficient internally heated combustion engine that can perform a high-efficient 2-stroke clean Otto or Diesel cycle 2) a simpler externally heated steam engine with no boiler requirement 3) an improved stirling engine system operating under two-phase flow conditions with high heat transfer rates from the heat source to the working gas. The new proposed geometry uses a novel concept system established between piston and cylinder that uses incompressible fluid like water as a medium to facilitate the sealing operation of the working fluid, gases for internal combustion engine configuration, steam for the steam engine or a gas/vapour to the stirling engine. The new sealing system totally avoids hot gases/ steam to escape from the cylinder during the combustion and expansion processes of the engine thermodynamic cycle. It also can eliminate the need of special lubricants in the cylinder walls as typically occurs in convention internal and external heated piston engines. This sealing concept allows injection of large amounts of water inside the cylinder that can be used in two different ways: a) for internal combustion engine configuration the water can be easily injected at the end of the expansion stroke to capture sensible heat from the gases producing steam that provides extra positive work in the expansion phase; b) for external heated steam engine, the water can be injected during the end of the compression phase against a hot surface producing steam necessary during the expansion phase. At the beginning of the compression phase water is injected against the steam reducing the cylinder pressure and the compression work; c) for the stirling engine liquid can be injected in the hot section by the displacer movement when located in the cold region.. Another extreme advantage is that for internal combustion engine applications, the geometry allows the use of an efficient simple scavenging pump outside the engine crankshaft area, allowing excellent scavenging process. This fact favors low-emissions production associated with possibility of achieving high amounts of work per cycle. Additionally the geometry favours the use of an efficient uniflow type scavenging procedure that can also uniquely use valves in both cylinder and piston that can favor engine cycle optimization. The possibility of using these valves allows the engine to easily perform operations close to Atkinson cycle. Alternatively, as an external heated steam engine, the use of valves or not can be adopted, depending on how complex and efficient the steam engine system is desired. Both these internal and external heated configurations are also very suitable as a cogeneration unit since water can be directly heated by the combustion gases and cylinder cooling walls without the need of complicated heat exchangers. The low-temperature of the sealing components, the absence of high-temperature lubrication, the possibility of not having valves can also make this design very suitable as a low-maintenance engine that can be used, as said above, for residential cogenaration systems or for third-world rural area power applications. For the stirling two-phase flow system can solve some of the problems associated with stirling engines in terms of the difficulties in transferring heat from the outside heat source and the working fluid. A liquid being injected against the hot surfaces of the stirling engine parts can easily remove heat and transfer it to the gas as part of the working fluid. This can simplify the heat exchanger components of this engine.