Waste heat collecting system having expansion device
First Claim
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1. A waste heat collecting apparatus for a vehicle comprising:
- an engine cooling circuit, through which engine cooling water is circulated; and
Rankine cycle having an expansion device, a condensing device, a refrigerant pump, and a heating device, which are connected in a closed circuit so that refrigerant is circulated in the closed circuit by the operation of the refrigerant pump, wherein the heating device is disposed in the engine cooling circuit for heating the refrigerant of the Rankine cycle with the heat of the engine cooling water, so that the refrigerant is converted to high pressure and high temperature refrigerant, the heating device is connected to an inlet side of the expansion device for supplying the high pressure refrigerant to the expansion device, the condensing device is connected to an outlet side of the expansion device for cooling down and condensing the refrigerant from the expansion device through heat exchange with the ambient air, so that the pressure of the refrigerant at the outlet side of the expansion device depends on a condensing capacity of the condensing device, the expansion device is of a fixed displacement type fluid machine, and an output shaft of the expansion device is driven to rotate by expansion of the refrigerant in a working chamber thereof, the expansion of the refrigerant is performed by a pressure difference of the refrigerant between the high pressure at the inlet side and low pressure at the outlet side of the expansion device, and a volume ratio of expansion for the expansion device is selected at a value, at which proper expansion of the refrigerant is achieved when the pressure difference between the high pressure and the low pressure is minimum.
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Abstract
An object of the invention is to provide a waste heat collecting system having an expansion device, in which an over expansion of refrigerant is prevented so that a loss to be caused by the over expansion is eliminated. A volume ratio of expansion for the expansion device is selected at a value, at which proper expansion of the refrigerant is achieved when the pressure difference between the high pressure and the low pressure is minimum.
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Citations
21 Claims
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1. A waste heat collecting apparatus for a vehicle comprising:
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an engine cooling circuit, through which engine cooling water is circulated; and
Rankine cycle having an expansion device, a condensing device, a refrigerant pump, and a heating device, which are connected in a closed circuit so that refrigerant is circulated in the closed circuit by the operation of the refrigerant pump, wherein the heating device is disposed in the engine cooling circuit for heating the refrigerant of the Rankine cycle with the heat of the engine cooling water, so that the refrigerant is converted to high pressure and high temperature refrigerant, the heating device is connected to an inlet side of the expansion device for supplying the high pressure refrigerant to the expansion device, the condensing device is connected to an outlet side of the expansion device for cooling down and condensing the refrigerant from the expansion device through heat exchange with the ambient air, so that the pressure of the refrigerant at the outlet side of the expansion device depends on a condensing capacity of the condensing device, the expansion device is of a fixed displacement type fluid machine, and an output shaft of the expansion device is driven to rotate by expansion of the refrigerant in a working chamber thereof, the expansion of the refrigerant is performed by a pressure difference of the refrigerant between the high pressure at the inlet side and low pressure at the outlet side of the expansion device, and a volume ratio of expansion for the expansion device is selected at a value, at which proper expansion of the refrigerant is achieved when the pressure difference between the high pressure and the low pressure is minimum. - View Dependent Claims (2, 3)
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4. A waste heat collecting apparatus for a vehicle comprising:
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Rankine cycle having an expansion device;
a condensing device;
a refrigerant pump; and
a heating device, wherein the expansion device, the condensing device, the refrigerant pump, and the heating device are connected in a closed circuit so that refrigerant is circulated in the closed circuit by the operation of the refrigerant pump, the expansion device generating a rotational driving force by expansion of the refrigerant;
an electric power generator operatively connected to the expansion device for generating the electric power when it is driven to rotate by the rotational driving force of the expansion device;
a pressure detecting device for detecting a pressure difference of the refrigerant between a pressure at a high pressure side of the expansion device and a pressure at a low pressure side of the expansion device; and
a pressure increasing means for increasing the pressure difference when the pressure difference detected by the pressure detecting device is lower than a predetermined pressure difference, so that the pressure difference becomes closer to the predetermined pressure difference.
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5. A rotational force generating apparatus comprising:
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a high pressure generating device for generating a high pressure of working fluid;
a low pressure generating device for generating a low pressure of the working fluid;
an expansion device having a fixed displacement and rotating an output shaft by a pressure difference of the working fluid between the high pressure generated by the high pressure generating device and the low pressure generated by the low pressure generating device, wherein a volume ratio of expansion for the expansion device is selected at a value, at which proper expansion of the working fluid is achieved when the pressure difference between the high pressure and the low pressure is minimum. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A control system for an expansion device comprising:
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an expansion device for generating a rotational driving force by expansion of high pressure and high temperature working fluid;
an electric power generator driven by the rotational driving force of the expansion device;
a pressure detecting device for detecting a pressure difference of the working fluid between a pressure at a high pressure side of the expansion device and a pressure at a low pressure side of the expansion device; and
a pressure increasing means for increasing the pressure difference when the pressure difference detected by the pressure detecting device is lower than a predetermined pressure difference, so that the pressure difference becomes closer to the predetermined pressure difference. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification