System and procedure for emptying a blocked HVAC drain pipe

Abstract

Method for emptying a drain pipe (46) configured to provide an outlet for condensate collected within a plenum (12) of a vehicle, comprising the following: by a control (50), Blocking passages between the plenum (12) and a cabin channel; and Activating a blower (28) of a ventilation arrangement (31) to create pressure within the plenum (12) and a drain channel (44) that bypasses the plenum (12) and connects the drain pipe (46) and the ventilation arrangement (31) to drain the drain pipe (46) which is connected to the plenum (12).

Description

TECHNICAL AREA

[0001] This disclosure relates to heating, ventilation and air conditioning (HVAC) systems for motor vehicles and methods for operating them. GENERAL STATE OF THE ART

[0002] Most vehicles are equipped with a cabin HVAC unit designed to transfer heat from the refrigerant and heated coolant into the air and blow that air into the vehicle cabin. The HVAC unit may include a heater core, an evaporator core, a plenum, and a plenum fan. The plenum may contain numerous deflector flaps and ducts that direct air to numerous vents located within the vehicle cabin. As the flaps within the plenum open or close, air flowing through the plenum is distributed from one vent system to another. As the heated air passes through the heater core and evaporator core, water vapor in the air surrounding the cores may condense and collect at the bottom of the plenum. The plenum may include a drain pipe used to remove the condensed liquid.Occasionally the drain pipe may become clogged and unable to drain the condensed liquid from the plenum.

[0003] US 5 983 659 A discloses a vehicle heating, ventilation and air conditioning system with a condensate drain, in which an additional cleaning channel opens at a first end into a downstream chamber of the unit between the evaporator and the radiator and connects at a second end to the outside of the vehicle. SUMMARY

[0004] According to one embodiment of this disclosure, a method for draining a pipe is provided to provide an outlet for condensate collected within a plenum inside a vehicle. The method can be carried out by a controller and may involve blocking passages between the plenum and a cabin duct, activating a blower of a ventilation arrangement to create pressure within the plenum and a drain duct that bypasses the plenum and connects the pipe and the arrangement, in order to drain the plenum drain pipe connected to the plenum.

[0005] The procedure can be initiated in response to a predetermined number of engine starts.

[0006] Blocking may involve closing a de-icing flap located between the plenum and the cabin duct.

[0007] The procedure may also involve, prior to activation, opening a fresh air circulation flap connected to the ventilation manifold assembly to draw air into the plenum and the drain duct located outside the vehicle.

[0008] The procedure may also include closing the fresh air circulation flap after activation to block a passage between the ventilation manifold assembly and the air inlet duct in order to build up pressure within the drain duct and plenum.

[0009] The procedure may also involve closing a mode flap located between the plenum and the cabin duct to prevent air from flowing out of the plenum in order to build up pressure within the plenum.

[0010] The procedure may also include closing a drain channel flap located inside the drain channel to prevent air from flowing through the drain channel and pipe after the cleaning step.

[0011] According to one embodiment of this disclosure, a vehicle HVAC device is disclosed. The device may include a pipe, a drain channel, and a blower. The pipe may be configured to provide an outlet for condensate that has collected within a plenum connecting a cabin duct to a ventilation manifold assembly. The drain channel may bypass the plenum and connect the pipe and the assembly. The blower of the assembly may be configured to build up pressure within the plenum and the drain channel to empty the pipe.

[0012] The device may include a de-icer valve. The de-icer valve may be connected between the plenum and the cabin duct. The de-icer valve can be operated from an open position to a closed position to facilitate pressure build-up within the plenum and the drain duct and to facilitate the emptying of the pipe.

[0013] The device may include a mode valve. The mode valve may be connected between the plenum and the cabin duct. The mode valve can be operated from an open position to a closed position. When the mode valve is closed, this can facilitate the accumulation of pressure for emptying the pipe within the plenum and the drain duct.

[0014] The device may include a fresh air damper that can be connected to the ventilation manifold assembly. The fresh air duct can be opened to facilitate a flow of air from the ventilation manifold assembly to the plenum and the exhaust duct.

[0015] The device may include a fresh air recirculation damper. The fresh air recirculation damper may be closed to block a passage between the ventilation manifold assembly and the air inlet duct, in order to build up pressure within the exhaust duct and plenum after the blower is activated.

[0016] According to yet another embodiment of this disclosure, a vehicle system is disclosed. The vehicle system may include a pipe configured to provide an outlet for condensate that has collected within a plenum connecting a cabin duct to a ventilation manifold assembly. The vehicle system may also include a drain duct bypassing the plenum and connecting the pipe and the assembly, and a control unit that may be configured to block passages between the plenum and the cabin duct and to activate a blower of the assembly to create pressure within the plenum and drain duct in order to empty the pipe. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic illustration of a vehicle HVAC system according to one embodiment of this disclosure. Fig. Figure 2 is a schematic illustration of a control system for a motor vehicle HVAC system. Fig. Figure 3 is a flowchart for the device, illustrating a method for operating the motor vehicle HVAC system. DETAILED DESCRIPTION

[0017] Detailed embodiments of the present invention are disclosed herein as required; however, it is understood that the disclosed embodiments are merely examples of the invention, which may be implemented in various and alternative forms. The figures are not necessarily to scale; some features may be enlarged or reduced to show details of certain components. Accordingly, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis to teach those skilled in the art the diverse uses of the present invention.

[0018] With reference to Fig. Figure 1 illustrates a vehicle HVAC system. The vehicle HVAC system 10 can include a plenum 12, which may contain or enclose a heating core or air conditioning evaporator core 14, or both, capable of receiving heated refrigerant from an engine or auxiliary heat source, including, but not limited to, coolant, electricity, etc. An air mixing flap 16 may be arranged between the evaporator core 18 and may be actuated by one or more vents to change its position, thereby controlling the amount of hot and cold air within the plenum 12 to achieve a desired temperature within the vehicle cabin. A de-icer or de-fog flap 20 and a mode flap 22 are operationally connected to the plenum 12. The de-icer or de-fog flap 20 is arranged between the plenum 12 and a de-icer nozzle 42. The mode flap 22 is arranged between the plenum 12 and a number of outlet vents 40.In particular, the de-icer or de-fog flap 20 is operationally connected between the plenum 12 and the outlet vents 40, which are located within a vehicle dashboard near the vehicle windshield. When open, the de-icer or de-fog flap 20 allows a flow of heated or cooled air from the plenum 12 to the outlet vents 40. The mode flap 22 is operable to open or close a path for various heating or cooling settings. For example, if an occupant wishes to defrost the windshield, the de-icer setting can be selected, and the de-icer or de-fog flap 20 can be actuated to allow a flow of heated air from the plenum 12 through the de-icer or de-fog flap 20 to the outlet vents 40.

[0019] As air flows through the heating and air conditioning evaporator core 14, water vapor in the surrounding air can condense and collect at the bottom of the plenum 12. This collected fluid can slosh and slosh within the plenum 12 as the vehicle moves. This movement can cause an unpleasant and disturbing noise for the cabin occupants. Additionally, if the fluid remains in the plenum 12 for an extended period, it can cause a musty, stale, or damp odor within the vehicle cabin, further disturbing the customers. The plenum 12 may include a drain pipe 46, which is used to drain the condensed fluid and prevent the noise and odor associated with the collected water within the plenum 12.Sometimes foreign objects, including but not limited to leaves, cobwebs, screws or other components, can accumulate within a vehicle HVAC system 10 inside the drain pipe 46 and cause a blockage or obstruction.

[0020] A ventilation manifold 24 connects the plenum 12 to a ventilation assembly or blower assembly 31, which consists of a blower coil 30, a fan 28, and a fan motor 26. The fan 28 can be driven by a fan motor 26. The fan motor 26 can receive an electrical signal for switching on and off from a controller 50 ( Fig. 2) received. Furthermore, the speed of the fan 28 can be set to various rates between minimum and maximum settings. The fan 28 can be operationally connected to an air inlet duct 36. A blower coil 30 and a filter 32 can be arranged between the air inlet duct 36 and the fan 28. However, the filter 32 can be arranged within the ventilation arrangement or blower arrangement 31 at a location other than the one described. The blower coil 30 can increase the energy in the air within the HVAC unit. A fresh air inlet damper 34 can be arranged within the air inlet duct 36. The fresh air inlet damper 34 can be positioned from an open to a closed position and any adjustable position in between.When open, the fresh air inlet flap 34 allows airflow from the fresh air opening 38 through the air inlet duct 36 via the fan 28.

[0021] A blockage-releasing channel or drain channel 44 can be arranged between the ventilation elbow 24 and the drain pipe 46. In the event of a blockage or obstruction in the drain pipe 46, the drain channel 44 can allow a flow of air, generated by the fan 28, from the air inlet channel 36 to the drain pipe 46 to clear the blockage. A drain channel flap 45 can be arranged within the drain channel 44. The drain channel flap 45 can be kept closed to prevent air from escaping through the drain channel 44 as it flows from the air inlet channel 36 to the plenum 12. In the event of a blockage in the drain pipe 46, or at a specific time interval, the drain channel flap 45 can be opened to drain the blocked or obstructed drain pipe 46. The drain channel flap 45 can be opened as soon as a blockage is detected or at a predetermined interval.

[0022] The ventilation manifold 24, the outlet vents 40, the ducts and de-icing nozzles 42, the unblocking duct or drain duct 44, the drain pipe 46, and the air inlet duct 36 can be made of various materials, including, but not limited to, ABS resins, polypropylene, and SMA resins. The components can be manufactured using various processes, such as blow molding or injection molding, to produce their complex shape and design. Alternatively, the components can be produced using other rapid manufacturing processes, such as 3D printing or other additive manufacturing techniques.

[0023] With reference to Fig. Figure 2 illustrates a vehicle HVAC control system. The control system may include a controller 50, which is electrically connected to numerous components of the vehicle HVAC system 10. The controller 50 can be a variety of controllers that can communicate via a serial bus (e.g., Controller Area Network (CAN), FlexRay, Ethernet, etc.) or via dedicated electrical lines. The controller generally includes any number of microprocessors, microcontrollers, ASICs, ICs, volatile (e.g., RAM, DRAM, SRAM, etc.) and non-volatile memory (e.g., FLASH, ROM, EPROM, EEPROM, MRAM, etc.), and software code to work together to perform a range of operations. The controller may also include predefined data or "lookup tables" based on calculations and test data, which are stored in the memory.The controller can communicate with other vehicle systems and controllers via one or more wired or wireless vehicle connections using common bus protocols (e.g., CAN, LIN, Ethernet, etc.). In the context of this text, a reference to "a controller" refers to one or more controllers.

[0024] The control unit 50 includes a data input 54 for receiving data corresponding to the status of the vehicle's ignition system. The data input 54 can receive data indicating the engine speed, measured in revolutions per minute, that powers the vehicle. Occupancy status, including but not limited to the status of the vehicle door locks, seat belt sensors, seat occupancy sensors, and other suitable sensors capable of monitoring the presence of vehicle occupants, can be received by the data input 54. In addition to the vehicle occupancy status, the vehicle occupant can select a specific heating or cooling setting, including but not limited to defrosting, defogging, air conditioning, and heating. The exhaust vents 40, floor vents, and rear vents 48 ( Fig. 1) can be opened to supply air to the cabin for the numerous heating and cooling settings. The heating and cooling settings can also be received from the data input 54. The number of on or off events can also be received by the controller 50 from the keyless entry device 52. The controller can calculate or determine the number of on or off events that are executed and compare this number to a predetermined value indicating a blocked drain pipe. Furthermore, the number of engine starts and stops can be compared to a predetermined value indicating a blocked drain. Finally, the data input 54 can receive data from an automotive mechanic to clear or empty the blocked drain pipe 46.

[0025] As further in Fig. As illustrated in Figure 2, the control unit 50 is operationally connected to the air mixing flap 16, the de-icer flap 20, the mode flap 22, and the fresh air intake flap 34 and their associated actuators (not shown). The actuators may include a small motor and one or more gear sets, each operationally connected to one of the aforementioned flaps. The control unit 50 is configured to adjust the air mixing flap 16, the de-icer flap 20, the mode flap 22, and the fresh air intake flap 34 between the open and closed positions.

[0026] With reference to Fig. Figure 3 illustrates a flowchart 100 for a procedure for operating the vehicle's HVAC system 10. In step 102, the control system branches to determine whether a trigger condition exists for draining the blocked drain. If so, the control system branches to step 104. In step 104, the air mixing flap 16, the de-icing flap 20, the mode flap 22, and the fresh air intake flap 34 can be closed after receiving a signal from the control system 50. Following step 104, the fresh air intake flap 34 is opened in step 106. When the air intake flap 34 is opened, fresh air can be drawn in by the fan 28 as soon as it is driven. In step 108, the air mixing flap 16 is set to full cooling mode. In full cooling mode, the fresh air intake flap 34 is closed. Closing the fresh air inlet flap 34 can increase the pressure inside the plenum 12.In step 109, the drain duct flap 45 can be opened to facilitate airflow through the drain duct 44. In step 110, the fan motor 26 and fan 28 can be set to maximum speed. At maximum speed, the fan 28 pushes air from the air inlet duct 36 through the drain duct 44 and through the drain pipe 46 to clear any blockage within the drain pipe 46.

[0027] It goes without saying that the flowchart in Fig. 3 serves only for illustrative purposes and that the procedure is not based on flowchart 100 in Fig. 3. It should be interpreted in a limited way. Some steps of the procedure may be rearranged, while others may be omitted entirely.

[0028] While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used in the description are descriptive and not limiting, and it is understood that various modifications can be made without deviating from the spirit and scope of the invention. Furthermore, the features of different implemented embodiments can be combined to form further embodiments of the invention.

Claims

[1] Method for emptying a drain pipe (46) configured to provide an outlet for condensate collected within a plenum (12) of a vehicle comprising: by a control (50), Blocking passages between the plenum (12) and a cabin channel; and Activating a blower (28) of a ventilation arrangement (31) to create pressure within the plenum (12) and a drain channel (44) that bypasses the plenum (12) and connects the drain pipe (46) and the ventilation arrangement (31) to drain the drain pipe (46) which is connected to the plenum (12). [2] Method according to claim 1, wherein the blocking is initiated in response to a predetermined number of engine starts. [3] Method according to claim 1, wherein the blocking includes closing a de-icing flap (20) arranged between the plenum (12) and the cabin duct. [4] Method according to claim 1, further comprising, prior to activation, opening a fresh air inlet flap (34) connected to a ventilation manifold (24) to draw air into the plenum (12) and the drain channel (44) located outside the vehicle. [5] Method according to claim 1, further comprising, after activation, closing the fresh air inlet flap (34) to block a passage between the ventilation manifold (24) and an air inlet duct (36) in order to further build up pressure within the drain duct (44) and the plenum (12). [6] Method according to claim 1, further comprising closing a mode flap (22) arranged between the plenum (12) and the cabin duct to prevent air from flowing out of the plenum (12) in order to further build up pressure inside the plenum. [7] Method according to claim 1, further comprising, after activation, closing a drain channel flap arranged inside the drain channel (44) to prevent air from flowing through the drain channel (44) and the drain pipe (46). [8] Vehicle HVAC system comprising the following: a drain pipe (46) configured to provide an outlet for condensate that has collected within a plenum (12) connecting a cabin duct to a ventilation manifold assembly (24); a drain channel (44) that bypasses the plenum (12) and connects the drain pipe (46) and the ventilation elbow assembly (24); and a blower (28) of the ventilation manifold assembly (24) configured to build up pressure within the plenum (12) and the drain channel (44) in order to empty the drain pipe (46). [9] Vehicle HVAC device according to claim 8, further comprising a de-icing flap (20) connected between the plenum (12) and the cabin duct and movable between an open position and a closed position to facilitate an accumulation of pressure within the plenum (12) and drain duct (44) for emptying the drain pipe (46). [10] Vehicle HVAC device according to claim 8, further comprising a mode flap (22) connected between the plenum (12) and the cabin duct and movable between an open position and a closed position to facilitate an accumulation of pressure within the plenum (12) and drain duct (44) for emptying the drain pipe (46). [11] Vehicle HVAC device according to claim 8, further comprising a fresh air inlet flap (34) connected to the ventilation manifold assembly (24) and configured to facilitate a flow of air from the ventilation manifold assembly (24) to the plenum (12) and the drain channel (44) when open. [12] Vehicle HVAC device according to claim 11, wherein the fresh air inlet flap (34) is further configured to block a passage between the ventilation manifold assembly (24) and an air inlet duct (36) when closed, in order to further build up pressure within the drain duct (44) and plenum (12). [13] Vehicle HVAC device according to claim 8, further comprising a drain channel flap (45) arranged inside the drain channel (44) to prevent air from flowing through the drain channel (44) and the drain pipe (46). [14] Vehicle system comprising the following: a drain pipe (46) configured to provide an outlet for condensate that has collected within a plenum (12) connecting a cabin duct to a ventilation manifold assembly (24); a drain channel (44) that bypasses the plenum (12) and connects the drain pipe (46) and the ventilation elbow assembly (24); and a control (50) configured to block passages between the plenum (12) and the cabin duct and to activate a blower (28) of a ventilation arrangement (31) to build up pressure within the plenum (12) and the drain duct (44) in order to empty the drain pipe (46). [15] Vehicle system according to claim 14, wherein the controller (50) is further configured to perform the blocking and activation in response to the occurrence of a number of activation events.

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