Method and system of controlling a thermodynamic system in a vehicle

Patent metadata

Field	Value
Publication number	US-2016201520-A1
Application number	US-201514596528-A
Country	US
Kind code	A1
Filing date	Jan 14, 2015
Priority date	Jan 14, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A vehicle has a vehicle system with a waste heat fluid. An expander, a condenser, a pump, and an evaporator are provided in sequential fluid communication in a thermodynamic cycle containing a working fluid. The evaporator is configured to transfer heat from the waste heat fluid to the working fluid. At least one valve adjacent to the pump is controlled to control fluid flow through at least one chamber to maintain a pressure of the fluid at a pump inlet at a threshold pressure above a saturated vapor pressure associated with a temperature at a condenser outlet when ambient temperature varies.

First claim

1 . A vehicle comprising:
a vehicle system having a waste heat fluid; an expander, a condenser, a pump, and an evaporator in sequential fluid communication in a thermodynamic cycle containing a working fluid, the evaporator configured to transfer heat from the waste heat fluid to the working fluid; a chamber connected to an inlet of the pump by an upstream valve, and connected to an outlet of the pump by a downstream valve; and a controller configured to control the upstream valve and the downstream valve such that a pressure of the working fluid at the inlet to the pump is at a threshold pressure, the threshold pressure being a saturated vapor pressure of the working fluid plus a pressure offset, the saturated vapor pressure a function of a temperature of the working fluid at an outlet of the condenser, the temperature and the saturated vapor pressure varying with ambient temperature.

2 . The vehicle of claim 1 further comprising a pressure sensor in fluid communication with the inlet to the pump;
wherein the controller is further configured to receive a signal from the pressure sensor indicative of the pressure of the working fluid at the inlet to the pump.

3 . The vehicle of claim 2 wherein the controller is further configured to control the upstream valve and the downstream valve by commanding the upstream valve to open and commanding the downstream valve to close in response to the pressure of the working fluid at the inlet being below the threshold pressure, the upstream valve configured to provide pressurized fluid from the chamber to the inlet to increase the pressure of the working fluid.

4 . The vehicle of claim 2 wherein the controller is further configured to control the upstream valve and the downstream valve by commanding the upstream valve to close and commanding the downstream valve to open in response to the pressure of the working fluid at the inlet being above the threshold pressure, the downstream valve configured to provide pressurized fluid from an outlet of the pump to the chamber and reduce the pressure of the working fluid.

5 . A vehicle comprising:
a vehicle system having a waste heat fluid; an expander, a condenser, a pump, and an evaporator in sequential fluid communication in a thermodynamic cycle containing a working fluid, the evaporator configured to transfer heat from the waste heat fluid to the working fluid; a plurality of chambers arranged in parallel fluid connection and positioned between the condenser and the pump; at least one valve in fluid communication with the plurality of chambers and configured to selectively control flow of the working fluid between the plurality of chambers; and a controller configured to control the at least one valve to vary a volume of the cycle such that a pressure of the working fluid at an inlet to the pump is at a threshold pressure, the threshold pressure being a saturated vapor pressure of the working fluid plus a pressure offset, the saturated vapor pressure a function of a temperature of the working fluid at an outlet of the condenser, the temperature and the saturated vapor pressure varying with ambient temperature.

6 . The vehicle of claim 5 wherein a first chamber of the plurality of chambers has a first volume, and a second chamber of the plurality of chambers has a second volume greater than the first volume.

7 . The vehicle of claim 6 further comprising a pressure sensor in fluid communication with the inlet to the pump;
wherein the controller is further configured to receive a signal from the pressure sensor indicative of the pressure of the working fluid at the inlet to the pump, and control the at least one valve to provide flow of the working fluid through the first chamber when the pressure is less than the threshold pressure to decrease the volume of the cycle and provide an increase in pressure at the inlet to the pump.

8 . The vehicle of claim 6 further comprising a pressure sensor in fluid communication with the inlet to the pump;
wherein the controller is further configured to receive a signal from the pressure sensor indicative of the pressure of the working fluid at the inlet to the pump, and control the at least one valve to provide flow of the working fluid through the second chamber when the pressure is greater than the threshold pressure to increase the volume of the cycle and provide an decrease in pressure at the inlet to the pump.

9 . The vehicle of claim 6 wherein a third chamber of the plurality of chambers has a third volume greater than the second volume; and
wherein the at least one valve comprises a valve associated with each chamber of the plurality of chambers.

10 . A method comprising:
controlling a pump, an evaporator, an expander, and a condenser in a closed loop in a vehicle for energy recovery using a mixed phase working fluid; and controlling at least one valve to a chamber adjacent to the pump to maintain a pressure of the fluid at a pump inlet at a threshold pressure above a saturated vapor pressure associated with a temperature at a condenser outlet when ambient temperature varies.

11 . The method of claim 10 wherein the threshold pressure is maintained at a pressure offset above the saturated vapor pressure.

12 . The method of claim 10 wherein the temperature of the condenser outlet is at an offset above ambient temperature; and
wherein the saturated vapor pressure increases with a temperature increase of the fluid at the condenser outlet.

13 . The method of claim 10 further comprising transferring heat to the fluid in the evaporator from a waste heat fluid in the vehicle thereby providing a vapor phase of the fluid;
rotating the expander using the vapor phase of the fluid to generate power;
transferring heat from the fluid in the condenser to ambient air thereby providing a liquid phase of the fluid; and
pumping the liquid phase of the fluid using the pump.

14 . The method of claim 10 wherein the at least one valve is an upstream valve fluidly connected to the pump inlet and to a chamber, the method further comprising:
controlling a downstream valve to maintain the pressure of the fluid at the pump inlet at the threshold pressure when ambient temperature varies, the downstream valve adjacent to the pump and fluidly connected to a pump outlet and to the chamber, wherein the chamber is in parallel fluid connection with the pump.

15 . The method of claim 14 further comprising:
receiving a signal from a pressure sensor in fluid communication with the pump inlet that the pressure is less than the threshold pressure; and
opening the upstream valve and closing the downstream valve to increase pressure at the pump inlet by providing pressurized fluid from the chamber to the pump inlet.

16 . The method of claim 14 further comprising:
receiving a signal from a pressure sensor in fluid communication with the pump inlet that the pressure is greater than the threshold pressure; and
closing the upstream valve and opening the downstream valve to lower pressure at the pump inlet by providing pressurized fluid from the pump outlet into the chamber.

17 . The method of claim 10 wherein the at least one valve is a first valve controlling flow through a first chamber positioned between the first valve and the pump inlet, the method further comprising:
controlling a second valve to maintain the pressure of the fluid at the pump inlet at the threshold pressure when ambient temperature varies, the second valve adjacent to the pump and controlling flow through a second chamber positioned between the second valve and the pu

Assignees

• Ford Global Tech Llc

Inventors

• Zhou Shiguang

Classifications

• F01K23/101 Primary

  Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence) · CPC title

• B60H1/004

  for vehicles having a combustion engine and electric drive means, e.g. hybrid electric vehicles · CPC title

• F01N5/02

  the devices using heat · CPC title

• Y10S903/904

  Component specially adapted for hev · CPC title

• B60R16/08

  fluid · CPC title