Stirling engine shortcomings
1. High requirements on materials. The maximum temperature of the internal combustion engine is much higher than that of Stirling, but the internal combustion engine relies on heat dissipation to control the temperature of the cylinder to about 90 degrees, while the heater and expansion chamber of the Stirling engine need to be kept at a higher temperature for a long time. Higher requirements are placed on the material.
2. Large heat loss. Also because of the high temperature maintained for a long time, this causes a lot of heat to be lost by direct transfer and heat radiation. Therefore, a series of measures are needed to reduce heat loss, such as making the piston a hollow structure and setting up multiple "thermal barriers" inside.
3. Large volume. This is caused by a series of measures to reduce heat loss, to be insulated, and the specific power is small.
4. Slow response. These are for Stirling engines of conventional construction. Since the heat source comes from the outside, heat transfer takes time, so it takes a while for the engine to change the temperature of the cylinder. This means that it takes time to warm up before providing effective power; it cannot quickly change its power output; sealing and lubrication problems. Sealing and lubrication are contradictory to some extent. Since the working medium is limited, the sealing requirements are high, which is one of the reasons why the Stirling engine was invented earlier than the internal combustion engine but did not develop very quickly. In order to reduce the friction loss, the lubrication requirements are also higher. Since the vaporization of the lubricating oil will condense on the regenerator and cause blockage, the lubricating oil cannot be used and only dry friction can be used. Countermeasure: Piston rings made of polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK) and various fillers (bronze, graphite, etc.), with automatic formation of lubricating layer (self-lubricating) and high temperature resistance (250 °C) The characteristics of Max).