Fluid machine, rankine cycle and control method

A fluid machine comprising:

• means for compressing or expanding a working fluid which is heated to be brought into a vapor phase state after circulating in a cycle;
• means for storing lubricant oil for lubricating a sliding surface of the fluidization means;
• a lubricant oil feed passage for guiding the lubricant oil stored in the storing means to a sliding portion of the compressing or expanding means by a flow of the working fluid;
• means for adjusting a sliding surface pressure of the sliding portion;
• and
• means for controlling the operation of the pressure adjusting means to perform a first sliding surface pressure decreasing mode and a second sliding surface pressure decreasing mode which involve decreasing the sliding surface pressure of the sliding portion,
• wherein the working fluid flows inside the fluid machine with the sliding surface pressure of the sliding portion decreased as compared with that in a normal operation of the compressing or expanding means by the adjusting means, and thereafter the decreasing of the sliding surface pressure by the adjusting means is released
• wherein the controlling means performs the first sliding surface pressure decreasing mode when the number of times of actuation of the compressing or expanding means after stopping of the engine and turning on of the ignition switch is less than a predetermined number, and performs the second sliding surface pressure decreasing mode when the number of times of actuation of the compressing or expanding means reaches the predetermined number or more, the second sliding surface pressure decreasing mode involving decreasing a circulation amount of the working fluid flowing inside the fluid machine as compared with that in the first sliding surface pressure decreasing mode.

A Rankine cycle comprising:

• a pump for pressurizing and feeding a working fluid;
• a heater for heating the working fluid pressurized and fed by the pump into a vapor-phase state;
• an expansion unit for generating a driving force by expanding the working fluid flowing from the heater;
• a condenser for condensing the working fluid flowing from the expansion unit;
• means for storing lubricant oil for lubricating a sliding surface of the expansion unit ;
• a lubricant oil feed passage for guiding the lubricant oil stored in the storing means to a sliding portion of the expansion unit by a flow of the working fluid;
• means for adjusting a sliding surface pressure of the sliding portion;
• and
• means for controlling operations of the pump and the adjusting,
• wherein the controlling means operates the pump with the sliding surface pressure of the sliding portion decreased as compared with that in a normal operation of the expansion unit by the adjusting means, and then stops the decreasing of the sliding surface pressure by the adjusting means;
• and
• wherein the controlling means starts a sliding surface pressure decreasing mode which involves decreasing the sliding surface pressure of the sliding portion when a temperature of a coolant for an engine exceeds a predetermined temperature in actuation of the expansion unit.

A Rankine cycle comprising:

• a pump for pressurizing and feeding a working fluid;
• a heater for heating the working fluid pressurized and fed by the pump into a vapor-phase state;
• an expansion unit for generating a driving force by expanding the working fluid flowing from the heater;
• a condenser for condensing the working fluid flowing from the expansion unit;
• means for storing lubricant oil for lubricating a sliding surface of the expansion unit;
• a lubricant oil feed passage for guiding the lubricant oil stored in the storing means to a sliding portion of the expansion unit by a flow of the working fluid;
• means for adjusting a sliding surface pressure of the sliding portion;
• and
• means for controlling operations of the pump and the adjusting means,
• wherein the controlling means operates the pump with the sliding surface pressure of the sliding portion decreased as compared with that in a normal operation of the expansion unit by the adjusting means, and then stops the decreasing of the sliding surface pressure by the adjusting means;
• wherein the controlling means is configured to perform a first sliding surface pressure decreasing mode and a second sliding surface pressure decreasing mode which involve decreasing the sliding surface pressure of the sliding portion, and
• wherein the controlling means performs the first sliding surface pressure decreasing mode when the number of times of actuation of the expansion unit after stopping of the engine and turning on of the ignition switch is less than a predetermined number, and performs the second sliding surface pressure decreasing mode when the number of times of actuation reaches the predetermined number or more, wherein the second sliding surface pressure decreasing mode involves decreasing a circulation amount of the working fluid flowing inside the Rankine cycle as compared with that in the first sliding surface pressure decreasing mode.