An engine comprising: a sealed and rigid case containing a liquid and a work mixture of gas and steam from the liquid, a heat source able to heat the liquid, a cold source able to cool the work mixture, a movable device positioned within the case, which can move between a first position where the movable device minimize the contact between the work mixture and the cold source, and maximize the contact between the liquid and the work mixture, and a second position where the movable device maximize the contact between the work mixture and the cold source, and minimize the contact between the liquid and the work mixture, an actuator able to move the movable device from the first position to the second position and vice versa.

An expander system for recovering waste heat, a waste heat recovery system including such an expander system, a vehicle including such a waste heat recovery system and a method for manufacturing such an expander system. The expander system includes a shaft and a coupling portion including a first sealing unit and a second sealing unit. The shaft is inserted through the coupling portion to an expanding unit. The first sealing unit and the second sealing unit are arranged facing one another along the shaft. The first sealing unit and the second sealing unit are configured to seal the shaft in an axial direction relative to the shaft.

An expander system for recovering waste heat, a waste heat recovery system including such an expander system, a vehicle including such a waste heat recovery system and a method for manufacturing such an expander system. The expander system includes a shaft and a coupling portion including a first sealing unit and a second sealing unit. The shaft is inserted through the coupling portion to an expanding unit. The first sealing unit and the second sealing unit are arranged facing one another along the shaft. The first sealing unit and the second sealing unit are configured to seal the shaft in an axial direction relative to the shaft.

A near-adiabatic engine has four stages in a cycle: a means of near adiabatically expanding the working fluid during the downstroke (expansion stroke); a means of cooling the working fluid at Bottom Dead Center (BDC); a means of near adiabatically compressing that cooled fluid from the lower pressure/temperature level at BDC to the higher level at Top Dead Center (TDC); and finally, a means of passing that working fluid back into the high pressure/temperature source in a balanced condition with minimal resistance to that flow.

An engine comprising: a sealed and rigid case containing a liquid and a work mixture of gas and steam from the liquid, a heat source able to heat the liquid, a cold source able to cool the work mixture, a movable device positioned within the case, which can move between a first position where the movable device minimize the contact between the work mixture and the cold source, and maximize the contact between the liquid and the work mixture, and a second position where the movable device maximize the contact between the work mixture and the cold source, and minimize the contact between the liquid and the work mixture, an actuator able to move the movable device from the first position to the second position and vice versa.

A near-adiabatic engine has four stages in a cycle: a means of near adiabatically expanding the working fluid during the downstroke (expansion stroke); a means of cooling the working fluid at Bottom Dead Center (BDC); a means of near adiabatically compressing that cooled fluid from the lower pressure/temperature level at BDC to the higher level at Top Dead Center (TDC); and finally, a means of passing that working fluid back into the high pressure/temperature source in a balanced condition with minimal resistance to that flow.

A near adiabatic engine has four stages in a cycle: (1) a means of adiabatically expanding the working fluid during the downstroke from a high pressure/temperature level to a low level; (2) a means of cooling the working fluid at Bottom Dead Center (BDC); (3) a means of adiabatically compressing that fluid from a low pressure/temperature level at BDC to the higher level at Top Dead Center (TDC); and finally, (4) a means of passing that working fluid back to the high pressure/temperature source in a balanced pressure environment so as to minimize the resistance of that flow. This disclosure teaches the means of achieving (2) and (3) as follows: (2) a means is disclosed of BDC cooling of the expanded working fluid in the working chamber, and (3) a means is disclosed of adiabatically compressing the working fluid into the pump chamber before cycling the fluid.

A multi-stage traveling wave thermoacoustic engine is disclosed. A plurality of heat engine stages are formed as a toroidal spiral cascade of N stages inside a pressure vessel. Each stage feeds into the next stage such that all of the thermoacoustic power cycles past a common set of thermal interfaces multiple times with the single domed pressure vessel. The inventive thermoacoustic engine is simpler and cheaper to manufacture and more reliable due to the minimization of hot joints.

A multi-stage traveling wave thermoacoustic engine is disclosed. A plurality of heat engine stages are formed as a toroidal spiral cascade of N stages inside a pressure vessel. Each stage feeds into the next stage such that all of the thermoacoustic power cycles past a common set of thermal interfaces multiple times with the single domed pressure vessel. The inventive thermoacoustic engine is simpler and cheaper to manufacture and more reliable due to the minimization of hot joints.

A near adiabatic engine has four stages in a cycle: (1) a means of adiabatically expanding the working fluid during the downstroke from a high pressure/temperature level to a low level; (2) a means of cooling the working fluid at Bottom Dead Center (BDC); (3) a means of adiabatically compressing that fluid from a low pressure/temperature level at BDC to the higher level at Top Dead Center (TDC); and finally, (4) a means of passing that working fluid back to the high pressure/temperature source in a balanced pressure environment so as to minimize the resistance of that flow. This disclosure teaches the means of achieving (2) and (3) as follows: (2) a means is disclosed of BDC cooling of the expanded working fluid in the working chamber, and (3) a means is disclosed of adiabatically compressing the working fluid into the pump chamber before cycling the fluid.