Hvac module with anti-backflow control and method of operation

Patent metadata

Field	Value
Publication number	US-2016305676-A1
Application number	US-201514854829-A
Country	US
Kind code	A1
Filing date	Sep 15, 2015
Priority date	Apr 14, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

HVAC module has an air inlet, an evaporator downstream of the blower and a heater downstream of the evaporator, and a rear mixing zone downstream of the evaporator and the heater, wherein a control valve prevents cold air from flowing back towards the hot air by regulating the pressure of the cold air. A method is devised to control anti-backflow control valve of such an HVAC module by the steps of reading pressure and temperatures at various points in the HVAC module; setting air flow and temperature discharge targets; calculating the resistance of the control valve and a bland valve; determining corresponding control valve and blend valve positions; and moving the control valve and blend valve to those corresponding positions.

First claim

What is claimed is:

1 . An HVAC module, comprising:
a housing defining an air inlet, a front zone air outlet, and a rear zone air outlet; an evaporator disposed within the housing downstream of the air inlet; a heater disposed within the housing downstream of the evaporator; a cold air chamber downstream of the evaporator defined in the housing between the evaporator and the heater, the cold air chamber having a first pressure; a hot air chamber downstream of the heater defined in the housing between the heater and a first interior surface of the housing, the hot air chamber having a second pressure quantitatively lower than the first pressure of the cold air chamber, the hot air chamber being in fluid communication with a rear zone mixing chamber defined by the housing, the rear zone mixing chamber having a third pressure and being in fluid communication with the rear zone air outlet; a cold air stream path defined by a second interior surface of the housing and an interior partition in the housing, the cold air stream path extending from the cold air chamber to the rear zone mixing chamber; and a control valve disposed in the housing between the cold air chamber and the rear zone mixing camber, the control valve configured to selectively control a release of cold air from the cold air chamber along the cold air stream path into the rear zone mixing chamber so as to control backflow of cold air into the hot chamber.

2 . The HVAC module of claim 1 , wherein the control valve throttles cold air from the cold air chamber thereby regulating the third pressure of the rear zone mixing chamber such that the third pressure remains quantitatively lower than the second pressure of the hot air chamber.

3 . The HVAC module of claim 2 , wherein the control valve acts independently of the fluid communication of the hot air chamber to the rear zone mixing chamber, such that the control valve does not affect the cross section of the fluid communication between the hot air chamber and the rear zone mixing chamber.

4 . The HVAC module of claim 1 , further comprising a rear zone blend valve disposed at an entrance of the rear zone mixing chamber, wherein the rear zone blend valve is configured to selectively direct air flow from the cold air stream and the hot air chamber to the rear air outlet.

5 . The HVAC module of claim 1 , wherein the control valve disposed in the housing between the cold air chamber and the rear zone mixing chamber is a butterfly valve.

6 . The HVAC module of claim 1 , wherein the control valve disposed in the housing between the cold air chamber and the rear zone mixing chamber is a flap valve.

7 . The HVAC module of claim 1 , further comprising a front zone mixing chamber defined by the housing and positioned downstream of the evaporator adjacent to the cold air chamber and the hot air chamber, the front zone mixing chamber being in fluid communication with the front zone air outlet.

8 . The HVAC module of claim 7 , further comprising a front zone blend valve disposed in the front zone mixing chamber, wherein the front zone blend valve is configured to selectively direct air flow from the cold air chamber and the hot air chamber to the front zone air outlet.

9 . The HVAC module of claim 1 , further comprising no more than one blower assembly configured to induce air to flow through the housing from the inlet to at least one of the front zone air outlet and the rear zone air outlet.

10 . A method of controlling a backflow of cold air into hot air chamber in an open architecture HVAC module having an air inlet, an evaporator downstream of the air inlet, a cold air chamber downstream of the evaporator, a heater downstream of the cold air chamber, a hot air chamber downstream of the heater, a rear zone mixing chamber downstream of the cold air chamber and the hot air chamber, a rear zone air outlet, a control valve disposed between the cold air chamber and the rear mixing chamber, and a blend valve disposed in the rear zone mixing chamber, the method comprising the steps of:
reading a pressure of the cold air chamber, a temperature of the cold air chamber, a pressure of the hot air chamber, a temperature of the hot air chamber, and a pressure of the rear zone mixing chamber; setting a discharge air flow rate target and a discharge temperature target for the rear zone air outlet; calculating a resistance of the control valve; calculating a resistance of the blend valve; determining a position of the control valve corresponding to the calculated resistance of the control valve, the determination based on pre-programmed control valve calibration data; determining a position of the blend valve corresponding to the calculated resistance of the blend valve, the determination based on pre-programmed blend valve calibration data; moving the control valve to the position of the control valve determined to correspond to the resistance of the control valve calculated; moving the blend valve to the position of the blend valve determined to correspond to the resistance of the blend valve calculated.

11 . The method of claim 10 , wherein the pre-programmed control valve calibration data is a control valve look-up table.

12 . The method of claim 10 , wherein the pre-programmed blend valve calibration data is a blend valve look-up table.

13 . The method of claim 10 , further comprising reading the position of the control valve, and the position of the blend valve, determining the resistance of the control valve based on pre-programmed control valve calibration data can be looked up from the pre-calibrated tables, determining and the resistance of the rear zone blend valve based on pre-programmed blend valve calibration data, calculating a discharge air flow rate, calculating a discharge temperature, comparing the calculated discharge air flow rate and the discharge temperature to the discharge air flow rate target and the discharge temperature target, and moving at least one of the control valve and rear zone blend valve.

14 . The method of claim 10 , wherein the HVAC module has no more than one blower assembly configured to induce air to flow through the housing from the inlet to both the front zone air outlet and the rear zone air outlet

Assignees

• Mahle Int Gmbh

Inventors

• Wang Mingyu
• Xia Yanping
• Liu Wen
• Kadle Prasad S
• Kinmartin Jeffrey C

Classifications

• F24F7/08 Primary

  with separate ducts for supplied and exhausted air {with provisions for reversal of the input and output systems} · CPC title

• B60H2001/00192

  to left and right part of passenger compartment · CPC title

• B60H2001/002

  to front and rear part of passenger compartment · CPC title

• B60H1/00678 Primary

  the axis of rotation being in the door plane, e.g. butterfly doors · CPC title

• B60H2001/00135

  Deviding walls for separate air flows · CPC title