US20130181059A1 - Testing apparatus for preventing freezing of relays in electrical components - Google Patents
Testing apparatus for preventing freezing of relays in electrical components Download PDFInfo
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- US20130181059A1 US20130181059A1 US13/350,056 US201213350056A US2013181059A1 US 20130181059 A1 US20130181059 A1 US 20130181059A1 US 201213350056 A US201213350056 A US 201213350056A US 2013181059 A1 US2013181059 A1 US 2013181059A1
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- internal atmosphere
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
Definitions
- vehicles can have a global market, vehicles are manufactured to operate under most weather conditions, including extreme heat and extreme cold. Because vehicles are made from a multitude of components provided by a multitude of suppliers, these components must also be made to operate under the same weather conditions. Different areas of the world present different weather challenges, and until a vehicle is operated in a particular area with severe and unusual weather conditions, vehicle component operating problems may not be anticipated until the actual weather condition is experienced. Testing components under these severe and unusual weather challenges would enable prevention of the potential problems caused by such weather.
- testing apparatus used to prevent freezing of relays in electrical components, particularly electrical components used in vehicles.
- One embodiment of a testing apparatus comprises a chamber with temperature control configured to control a temperature of an internal atmosphere of the chamber and a humidifier in fluid communication with the internal atmosphere of the chamber configured to supply humidified air to the internal atmosphere.
- a sealable opening in a wall of the chamber is configured to pass a wire harness from external the chamber to inside the chamber while maintaining a sealed environment within the chamber.
- the temperature control is configured to maintain a sub-zero temperature in the internal atmosphere while the humidifier maintains a saturated internal atmosphere.
- test chamber for simulating low temperature and high humidity atmospheric conditions comprises a sealable chamber having a first sealable opening configured to receive humidified air and a second sealable opening configured to receive a wire harness, a temperature controller configured to control a temperature of an internal atmosphere of the chamber and a humidity controller configured to control a relative humidity of the internal atmosphere of the chamber.
- the temperature controller is configured to maintain a sub-zero temperature in the internal atmosphere while the humidity controller is configured to maintain a saturated internal atmosphere.
- FIG. 1 is a flow diagram of conditions within an electrical component that can lead to the non-start condition
- FIGS. 2A and 2B are schematics of a relay in freezing conditions
- FIG. 3 is a schematic of a test chamber for simulating conditions to prevent freezing of relays in an electrical component
- FIG. 4 is the schematic of the test chamber of FIG. 3 in use
- FIG. 5 is a flow diagram of a method of preventing freezing of relays in an electrical component
- FIG. 6 is a flow diagram of another method of preventing freezing of relays in an electrical component
- FIG. 7 is a flow diagram of yet another method of preventing freezing of relays in an electrical component
- FIGS. 8A and 8B depict temperature cross-over graphs
- FIG. 9 is a flow diagram of a pre-conditioning method that can be used with the prevention methods disclosed herein.
- FIG. 1 is a flow diagram of the conditions within the power distribution module that can lead to the non-start condition.
- FIG. 1 when the vehicle is operated ( 10 ), the temperature of the power distribution module rises and moisture vapor is formed ( 12 ). When the vehicle is turned off ( 14 ), the temperature within the power distribution module drops ( 16 ). As the temperature drops, the moisture condenses and freezes ( 18 ). One of the places that the condensed moisture freezes is on the relays, and in particular, on the relay contacts.
- FIG. 2 A is a schematic of a relay 24 for use in an electrical component with the moisture vapor condensing at the low points of the relay and freezing. If the temperature of the contact 26 drops below the ambient air temperature, moisture in the air condenses and forms ice on the contacts, and the contacts are prevented from closing ( 20 ). When a user attempts to start the vehicle again, the electrical component fails to operate as the ice on the relays is preventing the contacts from closing ( 22 ).
- FIG. 2B is a schematic of ice built up on the contact 26 within the relay 24 .
- FIG. 3 is a schematic of a test chamber 30 to simulate low temperature and high humidity atmospheric conditions.
- the test chamber 30 has a temperature control 32 configured to control the temperature of an internal atmosphere 34 of the test chamber 30 .
- a humidifier 36 is in fluid communication with the internal atmosphere 34 of the test chamber 30 and is configured to selectively supply humidified air 38 to the internal atmosphere 34 .
- a sealable opening 40 in a wall 42 of the test chamber 30 is configured to pass a wire harness (shown in FIG. 4 ) from external the test chamber 30 to within the internal atmosphere 34 of the test chamber 30 while maintaining a sealed environment within the test chamber 30 .
- the temperature control 32 is configured to maintain the internal atmosphere 34 at a sub-zero temperature while the humidifier 36 maintains a saturated internal atmosphere 34 .
- the temperature control 32 is configured to selectively maintain the set temperature of the internal atmosphere 34 .
- the set temperature of the internal atmosphere can range from about ⁇ 30° C. to 110° C. as a non-limiting example.
- the humidity controller 37 for the humidifier 36 is configured to selectively produce relative humidity up to 90% or higher while the set temperature is maintained.
- the test chamber 30 can have a window 43 , shown in broken line, through which one can monitor the internal atmosphere 34 of the test chamber 30 .
- the window 43 can be a second door which seals closed to the test chamber 30 or can be a sealed transparent opening in a wall.
- Monitoring the internal atmosphere 34 may be desirable to protect the equipment from damage due to freezing as the sub-zero temperature and high humidity conditions can lead to snow and ice build-up in the equipment.
- the test chamber 30 can also include one or more sealable apertures 45 , also shown in broken line, that allow a user to reach into the internal atmosphere 34 without disturbing the conditions of the atmosphere and manipulate an electrical component that is being tested.
- FIG. 4 is a schematic of the test chamber 30 of FIG. 3 in operation testing an electrical component of a vehicle 5 .
- one or more relays 24 within the electrical component 44 of a vehicle 5 are being tested.
- a wire harness 46 is passed through the sealable opening 40 in the wall 42 of the test chamber 30 and connects the vehicle 5 to the electrical component 44 to power the electrical component 44 .
- the electrical component 44 is sealed in the test chamber 30 so that the internal atmosphere 34 of the test chamber 30 can be efficiently manipulated to replicate the desired temperature and humidity conditions.
- a power generator can be attached to the wire harness 46 to supply power to the electrical component 44 in the test chamber 30 .
- the entry for the humidifier 36 and the sealable opening 40 for the wire harness 46 are shown in wall 42 as a non-liming example.
- the entry for the humidifier 36 and the sealable opening 40 can be in any wall and do not have to be on the same wall.
- the test chamber 30 be of a sufficient size to test components while in the vehicle 5 .
- FIG. 5 is a flow diagram of a method that utilizes the test chamber 30 disclosed herein.
- the method of FIG. 5 prevents freezing of relays 24 in an electrical component 44 of a vehicle 5 .
- the method comprises the step 50 of simulating operation of the electrical component in a sub-zero temperature and high humidity condition.
- step 52 the electrical component is allowed to cool down in an un-powered state in the sub-zero temperature and high humidity condition.
- the freeze potential of the relay is determined.
- FIG. 6 is a flow diagram of another method that utilizes the test chamber 30 disclosed herein.
- the method of FIG. 6 prevents freezing of relays 24 in an electrical component 44 of a vehicle 5 .
- the method comprises the step 56 of sealing the electrical component 44 having the relay 24 within the test chamber 30 .
- the test chamber 30 has a temperature control 32 that is configured to control a temperature of an internal atmosphere 34 of the test chamber 30 .
- the electrical component 44 is connected to the wire harness 46 while in the test chamber 30 to receive power from a power source.
- the test chamber 30 should be sealed to improve and make regulation of the atmospheric condition within the test chamber 30 more reliable and repeatable.
- the temperature of the internal atmosphere 34 of the test chamber 30 is reduced to a sub-zero temperature.
- the temperature can be reduced to below zero to as low as ⁇ 30° C. In particular, the temperature can be reduced to ⁇ 20° C. or below.
- the internal atmosphere 34 of the test chamber 30 is then humidified with saturated air supplied from the humidifier 36 in step 60 , which is in fluid communication with the internal atmosphere 34 .
- the relative humidity of the internal chamber 34 can be as saturated as possible without producing snow in the internal chamber 34 . Some snow can be produced, but the amount of snow should be limited so that it does not infiltrate the controls of the chamber 30 and cause them to freeze over and disrupt operation of the chamber 30 .
- the relative humidity can be 90% or higher.
- the electrical component 44 is provided with power from the power source for a first period of time, simulating operation of the electrical component 44 by idling the power source in a sub-zero temperature atmosphere with humidity.
- the first period of time can be any length of time.
- the first period of time is a sufficient time that heats the power distribution module to operating temperature while maintaining an efficient test schedule, such as approximately ten minutes.
- the power source is then shut down in step 64 and the electrical component 44 is left un-powered for a second period of time in the same sub-zero temperature atmosphere with humidity.
- the second period of time can be any length of time that allows the power distribution module sufficient time to cool to atmospheric temperature, such as approximately sixty minutes.
- the second period of time is typically longer than the first period of time.
- power is provided to the electrical component 44 for a second time.
- a freeze potential of the relay 24 is determined in step 68 .
- a low freeze potential is determined in step 72 if the electrical component 44 starts up in step 70 when power is provided for the second time to the electrical component 44 .
- a high freeze potential is determined in step 76 if the electrical component 44 does not start up in step 74 when power is provided for the second time to the electrical component 44 .
- the method in FIG. 6 can further include modification in step 78 . If the high freeze potential is determined, a modification is made in step 78 to the relay 24 and/or the electrical component 44 configured to decrease the high freeze potential. The modified relay 24 and/or electrical component 44 can be retested to confirm that the freeze potential has been reduce to a low freeze potential.
- an electrical component 44 having relays 24 that are tested by the methods disclosed herein is a power distribution module.
- the relays 24 within the power distribution module can freeze in humid sub-zero temperature conditions. Ice builds up on the contacts 26 of the relays 24 when the moisture vapor condenses and freezes. The ice buildup prevents closure of the contacts 26 , which prevents current flow and renders the vehicle 5 inoperable as the engine will not start.
- the power distribution module is the electrical component 44 being tested, and the problem occurs, one or both of the relays 24 and the power distribution module can be modified to prevent the ice build-up on the contacts 26 .
- the modification can include one or more of removing existing heat dissipaters from the power distribution module; adding ventilation to one or both of the power distribution module and the relay; moving the relay to a different location within the power distribution module; and moving the power distribution module to a different location within an engine compartment of the vehicle.
- FIG. 7 Another method of preventing freezing of relays in electrical components is disclosed herein with regard to FIG. 7 .
- the method shown in FIG. 7 also utilizes the test chamber 30 disclosed herein.
- the method comprises monitoring a temperature of a contact 26 in a relay 24 with a first thermocouple located on the contact 26 in step 80 .
- the ambient temperature within the relay 24 is monitored with a second thermocouple in step 82 .
- operation of the electrical component 44 within which the relay 24 resides is simulated in step 84 in an atmosphere with a sub-zero temperature and high humidity condition.
- Simulating operation of the electrical component in step 84 can include placing the electrical component 44 in a test chamber 30 as disclosed herein with temperature control 32 configured to control a temperature of an internal atmosphere 34 of the test chamber 30 .
- the temperature of the internal atmosphere 34 of the test chamber 30 is reduced to a sub-zero temperature and the internal atmosphere 34 is humidified with saturated air supplied from a humidifier 36 in fluid communication with the internal atmosphere 34 .
- Power is provided to the electrical component 44 for a first period of time.
- the first period of time can be any time sufficient to bring the electrical component 44 up to operating temperature.
- the first period of time can be approximately ten minutes.
- the humid, sub-zero temperature atmosphere can be produced in the test chamber 30 disclosed herein.
- the temperature can be reduced to below zero to as low as ⁇ 30° C. In particular, the temperature can be reduced to ⁇ 20° C. or below.
- the internal atmosphere 34 of the test chamber 30 is then humidified with saturated air supplied from the humidifier 36 to produce the humidity.
- the relative humidity of the internal chamber 34 can be as saturated as possible without producing snow in the internal chamber 34 . As a non-limiting example, the relative humidity can be 90% or higher.
- step 86 power to the electrical component 44 is stopped and the electrical component cools down in the atmosphere with a sub-zero temperature and high humidity condition. Monitoring of the contact temperature and ambient temperature continues to be monitored during the cool down period.
- step 88 the contact temperature 100 and the ambient temperature 102 are plotted as shown in FIGS. 8A and 8B .
- the freeze potential of the relay 24 is determined in step 90 by the temperature cross-over curve 104 produced from plotting the contact temperature 100 and the ambient temperature 102 against time. If the contact temperature 100 drops faster than the ambient temperature 102 , and the drop is fast enough that the contact temperature 100 and the ambient temperature 102 have a crossing point 106 on the temperature cross-over curve 104 , as shown in FIG. 8B , a high freeze potential of the relay 24 is determined. If the contact temperature 100 and the ambient temperature 102 do not cross on the temperature cross-over curve 104 , as shown in FIG. 8A , a low freeze potential of the relay 24 is determined. If the relay 24 is determined to have a high freeze potential, one or both of the relay 24 and the electrical component 44 can be modified in step 92 to decrease the high freeze potential.
- an electrical component 44 having relays 24 that are tested by the methods disclosed herein is a power distribution module.
- the power distribution module is sealed within the test chamber 30 and connected to a vehicle 5 with a wire harness 46 to power the power distribution module.
- the vehicle 5 is started and idled for a first period of time, simulating operation of the electrical component 44 in a sub-zero temperature atmosphere with humidity.
- the first period of time can be any length of time.
- a non-limiting example the first period of time is a sufficient time that heats the power distribution module to operating temperature while maintaining an efficient test schedule, such as approximately ten minutes.
- the vehicle 5 is then turned off and the power distribution module is left un-powered to cool down for a second period of time in the same sub-zero temperature atmosphere with humidity.
- the second period of time can be any length of time that allows the power distribution module sufficient time to cool to atmospheric temperature, such as approximately sixty minutes.
- the second period of time is typically longer than the first period of time.
- the relays 24 within the power distribution module can freeze in humid sub-zero temperature conditions. Ice builds up on the contacts 26 of the relays 24 when the moisture vapor condenses and freezes. The ice buildup prevents closure of the contacts 26 , which prevents current flow and renders the vehicle 5 inoperable as the engine will not start.
- the power distribution module is the electrical component 44 being tested, and the problem occurs, one or both of the relays 24 and the power distribution module can be modified to prevent the ice build-up on the contacts 26 .
- the modification can include one or more of removing existing heat dissipaters from the power distribution module; adding ventilation to one or both of the power distribution module and the relay; moving the relay to a different location within the power distribution module; and moving the power distribution module to a different location within an engine compartment of the vehicle.
- any of the methods herein can include pre-conditioning the relay prior to simulating operation of the electrical component.
- the pre-conditioning can occur before temperature monitoring in the second disclosed method, but the temperatures can also be monitored during pre-conditioning.
- FIG. 9 illustrates pre-conditioning of the relay 24 .
- the relay 24 is dried for a third period of time.
- the drying in step 110 can comprise operating the electrical component 44 in a high heat and low humidity condition in step 112 and holding the electrical component 44 in the high heat and low humidity condition in a power-off state in step 114 .
- the drying step can take place at sufficient temperature to remove moisture from the electrical component 44 .
- the drying can occur at about 100° C. and zero or low humidity.
- the relay 24 is soaked in a high temperature and high humidity condition for a fourth period of time in step 116 .
- the high temperature and high humidity condition can occur at a temperature of about 80° C. or higher and a humidity of about 90% relative humidity or higher as a non-limiting example.
- the fourth period of time can be any sufficient amount of time known to those skilled in the art. As a non-limiting example, the fourth period of time is about 90 hours or greater.
- the relay 24 is sealed in a sealable container within the test chamber 30 and is then cooled from the high temperature, to room temperature, and then to a sub-zero temperature in step 118 .
- the electrical component 44 can be disconnected from the wire harness 46 for this step and to achieve a tight seal within the container.
- the relay 24 is held at the sub-zero temperature for a fifth period of time in step 120 .
- the sub-zero temperature can be as low as allowed by the test chamber 30 .
- the sub-zero temperature can be about ⁇ 20° C. or below.
- the fifth period of time can be about 20 hours or greater as a non-limiting example.
- the electrical component 44 can be removed from the sealed container and reattached to the wire harness 46 . Simulation of operation of the electrical component 44 can then be initiated as disclosed in the methods herein.
- Different relays may have different temperature cross-over profiles depending on the electrical component in which the respective relay is located. When the temperature cross-over profile is created for a relay in an electrical component, the temperature cross-over profile can be used to easily test different manufacturers and different modifications to confirm a low freeze potential of the relay.
Abstract
Disclosed herein are embodiments of testing apparatus used to prevent freezing of relays in electrical components, particularly electrical components used in vehicles. One embodiment of a testing apparatus comprises a chamber with temperature control configured to control a temperature of an internal atmosphere of the chamber and a humidifier in fluid communication with the internal atmosphere of the chamber configured to supply humidified air to the internal atmosphere. A sealable opening in a wall of the chamber is configured to pass a wire harness from external the chamber to inside the chamber while maintaining a sealed environment within the chamber. The temperature control is configured to maintain a sub-zero temperature in the internal atmosphere while the humidifier maintains a saturated internal atmosphere.
Description
- Because vehicles can have a global market, vehicles are manufactured to operate under most weather conditions, including extreme heat and extreme cold. Because vehicles are made from a multitude of components provided by a multitude of suppliers, these components must also be made to operate under the same weather conditions. Different areas of the world present different weather challenges, and until a vehicle is operated in a particular area with severe and unusual weather conditions, vehicle component operating problems may not be anticipated until the actual weather condition is experienced. Testing components under these severe and unusual weather challenges would enable prevention of the potential problems caused by such weather.
- Disclosed herein are embodiments of testing apparatus used to prevent freezing of relays in electrical components, particularly electrical components used in vehicles. One embodiment of a testing apparatus comprises a chamber with temperature control configured to control a temperature of an internal atmosphere of the chamber and a humidifier in fluid communication with the internal atmosphere of the chamber configured to supply humidified air to the internal atmosphere. A sealable opening in a wall of the chamber is configured to pass a wire harness from external the chamber to inside the chamber while maintaining a sealed environment within the chamber. The temperature control is configured to maintain a sub-zero temperature in the internal atmosphere while the humidifier maintains a saturated internal atmosphere.
- Another embodiment of a test chamber for simulating low temperature and high humidity atmospheric conditions disclosed herein comprises a sealable chamber having a first sealable opening configured to receive humidified air and a second sealable opening configured to receive a wire harness, a temperature controller configured to control a temperature of an internal atmosphere of the chamber and a humidity controller configured to control a relative humidity of the internal atmosphere of the chamber. The temperature controller is configured to maintain a sub-zero temperature in the internal atmosphere while the humidity controller is configured to maintain a saturated internal atmosphere.
- The various features, advantages and other uses of the present apparatus will become more apparent by referring to the following detailed description and drawing in which:
-
FIG. 1 is a flow diagram of conditions within an electrical component that can lead to the non-start condition; -
FIGS. 2A and 2B are schematics of a relay in freezing conditions; -
FIG. 3 is a schematic of a test chamber for simulating conditions to prevent freezing of relays in an electrical component; -
FIG. 4 is the schematic of the test chamber ofFIG. 3 in use; -
FIG. 5 is a flow diagram of a method of preventing freezing of relays in an electrical component; -
FIG. 6 is a flow diagram of another method of preventing freezing of relays in an electrical component; -
FIG. 7 is a flow diagram of yet another method of preventing freezing of relays in an electrical component; -
FIGS. 8A and 8B depict temperature cross-over graphs; and -
FIG. 9 is a flow diagram of a pre-conditioning method that can be used with the prevention methods disclosed herein. - Some areas of the world experience sub-zero weather conditions on a routine basis. Vehicles are designed to operate in these sub-zero temperatures by simulating such conditions and finding solutions when operating issues arise under the simulated conditions. However, certain weather conditions have been difficult to simulate and, as a result, are often not simulated, resulting in operating issues arising during operation of the vehicle by a customer when these certain weather conditions occur.
- One of the weather conditions that have been difficult and costly to simulate is severe cold coupled with humidity. Although severe cold has been simulated, the resulting atmosphere typically has low or no humidity. The combination of the severe cold with humidity presents unique challenges to some vehicle components that could be addressed if the vehicle or vehicle components could be tested in such a simulated atmosphere prior to being sold.
- One non-limiting example of a problem arising from the combination of severe cold and humidity occurs with the relay or relays within an electrical component of a vehicle. As a non-limiting example, relays within the power distribution module of the vehicle that supply current to the starter circuit during start-up of the vehicle can be affected. Under certain conditions, these relays could potentially freeze and prevent the vehicle from starting. The inventors discovered the cause of the problem.
FIG. 1 is a flow diagram of the conditions within the power distribution module that can lead to the non-start condition. - As shown in
FIG. 1 , when the vehicle is operated (10), the temperature of the power distribution module rises and moisture vapor is formed (12). When the vehicle is turned off (14), the temperature within the power distribution module drops (16). As the temperature drops, the moisture condenses and freezes (18). One of the places that the condensed moisture freezes is on the relays, and in particular, on the relay contacts.FIG. 2 A is a schematic of arelay 24 for use in an electrical component with the moisture vapor condensing at the low points of the relay and freezing. If the temperature of thecontact 26 drops below the ambient air temperature, moisture in the air condenses and forms ice on the contacts, and the contacts are prevented from closing (20). When a user attempts to start the vehicle again, the electrical component fails to operate as the ice on the relays is preventing the contacts from closing (22).FIG. 2B is a schematic of ice built up on thecontact 26 within therelay 24. - In order to solve this problem, the inventors developed an apparatus for replicating the conditions in which the problem occurs.
FIG. 3 is a schematic of atest chamber 30 to simulate low temperature and high humidity atmospheric conditions. Thetest chamber 30 has atemperature control 32 configured to control the temperature of aninternal atmosphere 34 of thetest chamber 30. A humidifier 36 is in fluid communication with theinternal atmosphere 34 of thetest chamber 30 and is configured to selectively supplyhumidified air 38 to theinternal atmosphere 34. Asealable opening 40 in awall 42 of thetest chamber 30 is configured to pass a wire harness (shown inFIG. 4 ) from external thetest chamber 30 to within theinternal atmosphere 34 of thetest chamber 30 while maintaining a sealed environment within thetest chamber 30. Thetemperature control 32 is configured to maintain theinternal atmosphere 34 at a sub-zero temperature while the humidifier 36 maintains a saturatedinternal atmosphere 34. - The
temperature control 32 is configured to selectively maintain the set temperature of theinternal atmosphere 34. The set temperature of the internal atmosphere can range from about −30° C. to 110° C. as a non-limiting example. Thehumidity controller 37 for the humidifier 36 is configured to selectively produce relative humidity up to 90% or higher while the set temperature is maintained. - The
test chamber 30 can have awindow 43, shown in broken line, through which one can monitor theinternal atmosphere 34 of thetest chamber 30. Thewindow 43 can be a second door which seals closed to thetest chamber 30 or can be a sealed transparent opening in a wall. Monitoring theinternal atmosphere 34 may be desirable to protect the equipment from damage due to freezing as the sub-zero temperature and high humidity conditions can lead to snow and ice build-up in the equipment. - The
test chamber 30 can also include one or moresealable apertures 45, also shown in broken line, that allow a user to reach into theinternal atmosphere 34 without disturbing the conditions of the atmosphere and manipulate an electrical component that is being tested. -
FIG. 4 is a schematic of thetest chamber 30 ofFIG. 3 in operation testing an electrical component of a vehicle 5. As used in this example, one ormore relays 24 within theelectrical component 44 of a vehicle 5 are being tested. As illustrated, awire harness 46 is passed through thesealable opening 40 in thewall 42 of thetest chamber 30 and connects the vehicle 5 to theelectrical component 44 to power theelectrical component 44. Theelectrical component 44 is sealed in thetest chamber 30 so that theinternal atmosphere 34 of thetest chamber 30 can be efficiently manipulated to replicate the desired temperature and humidity conditions. - It is contemplated that instead of the vehicle 5, a power generator can be attached to the
wire harness 46 to supply power to theelectrical component 44 in thetest chamber 30. The entry for the humidifier 36 and thesealable opening 40 for thewire harness 46 are shown inwall 42 as a non-liming example. The entry for the humidifier 36 and thesealable opening 40 can be in any wall and do not have to be on the same wall. It is also contemplated that thetest chamber 30 be of a sufficient size to test components while in the vehicle 5. -
FIG. 5 is a flow diagram of a method that utilizes thetest chamber 30 disclosed herein. The method ofFIG. 5 prevents freezing ofrelays 24 in anelectrical component 44 of a vehicle 5. The method comprises thestep 50 of simulating operation of the electrical component in a sub-zero temperature and high humidity condition. Instep 52, the electrical component is allowed to cool down in an un-powered state in the sub-zero temperature and high humidity condition. In step 54, the freeze potential of the relay is determined. -
FIG. 6 is a flow diagram of another method that utilizes thetest chamber 30 disclosed herein. The method ofFIG. 6 prevents freezing ofrelays 24 in anelectrical component 44 of a vehicle 5. The method comprises thestep 56 of sealing theelectrical component 44 having therelay 24 within thetest chamber 30. Thetest chamber 30 has atemperature control 32 that is configured to control a temperature of aninternal atmosphere 34 of thetest chamber 30. Theelectrical component 44 is connected to thewire harness 46 while in thetest chamber 30 to receive power from a power source. Thetest chamber 30 should be sealed to improve and make regulation of the atmospheric condition within thetest chamber 30 more reliable and repeatable. - In
step 58, the temperature of theinternal atmosphere 34 of thetest chamber 30 is reduced to a sub-zero temperature. As a non-limiting example, the temperature can be reduced to below zero to as low as −30° C. In particular, the temperature can be reduced to −20° C. or below. Theinternal atmosphere 34 of thetest chamber 30 is then humidified with saturated air supplied from the humidifier 36 instep 60, which is in fluid communication with theinternal atmosphere 34. The relative humidity of theinternal chamber 34 can be as saturated as possible without producing snow in theinternal chamber 34. Some snow can be produced, but the amount of snow should be limited so that it does not infiltrate the controls of thechamber 30 and cause them to freeze over and disrupt operation of thechamber 30. As a non-limiting example, the relative humidity can be 90% or higher. - In
step 62, theelectrical component 44 is provided with power from the power source for a first period of time, simulating operation of theelectrical component 44 by idling the power source in a sub-zero temperature atmosphere with humidity. The first period of time can be any length of time. A non-limiting example the first period of time is a sufficient time that heats the power distribution module to operating temperature while maintaining an efficient test schedule, such as approximately ten minutes. The power source is then shut down instep 64 and theelectrical component 44 is left un-powered for a second period of time in the same sub-zero temperature atmosphere with humidity. The second period of time can be any length of time that allows the power distribution module sufficient time to cool to atmospheric temperature, such as approximately sixty minutes. The second period of time is typically longer than the first period of time. Instep 66, power is provided to theelectrical component 44 for a second time. - A freeze potential of the
relay 24 is determined instep 68. A low freeze potential is determined instep 72 if theelectrical component 44 starts up instep 70 when power is provided for the second time to theelectrical component 44. A high freeze potential is determined instep 76 if theelectrical component 44 does not start up instep 74 when power is provided for the second time to theelectrical component 44. - The method in
FIG. 6 can further include modification in step 78. If the high freeze potential is determined, a modification is made in step 78 to therelay 24 and/or theelectrical component 44 configured to decrease the high freeze potential. The modifiedrelay 24 and/orelectrical component 44 can be retested to confirm that the freeze potential has been reduce to a low freeze potential. - One example of an
electrical component 44 havingrelays 24 that are tested by the methods disclosed herein is a power distribution module. Therelays 24 within the power distribution module can freeze in humid sub-zero temperature conditions. Ice builds up on thecontacts 26 of therelays 24 when the moisture vapor condenses and freezes. The ice buildup prevents closure of thecontacts 26, which prevents current flow and renders the vehicle 5 inoperable as the engine will not start. When the power distribution module is theelectrical component 44 being tested, and the problem occurs, one or both of therelays 24 and the power distribution module can be modified to prevent the ice build-up on thecontacts 26. - The modification can include one or more of removing existing heat dissipaters from the power distribution module; adding ventilation to one or both of the power distribution module and the relay; moving the relay to a different location within the power distribution module; and moving the power distribution module to a different location within an engine compartment of the vehicle. These modifications are provided as non-limiting examples. Any modification known to those skilled in the art that would achieve the desired results is contemplated herein.
- Another method of preventing freezing of relays in electrical components is disclosed herein with regard to
FIG. 7 . The method shown inFIG. 7 also utilizes thetest chamber 30 disclosed herein. As shown inFIG. 7 , the method comprises monitoring a temperature of acontact 26 in arelay 24 with a first thermocouple located on thecontact 26 in step 80. At the same time, the ambient temperature within therelay 24 is monitored with a second thermocouple instep 82. While the temperatures are being monitored, operation of theelectrical component 44 within which therelay 24 resides is simulated instep 84 in an atmosphere with a sub-zero temperature and high humidity condition. - Simulating operation of the electrical component in
step 84 can include placing theelectrical component 44 in atest chamber 30 as disclosed herein withtemperature control 32 configured to control a temperature of aninternal atmosphere 34 of thetest chamber 30. The temperature of theinternal atmosphere 34 of thetest chamber 30 is reduced to a sub-zero temperature and theinternal atmosphere 34 is humidified with saturated air supplied from a humidifier 36 in fluid communication with theinternal atmosphere 34. Power is provided to theelectrical component 44 for a first period of time. The first period of time can be any time sufficient to bring theelectrical component 44 up to operating temperature. For example, the first period of time can be approximately ten minutes. - The humid, sub-zero temperature atmosphere can be produced in the
test chamber 30 disclosed herein. As a non-limiting example, the temperature can be reduced to below zero to as low as −30° C. In particular, the temperature can be reduced to −20° C. or below. Theinternal atmosphere 34 of thetest chamber 30 is then humidified with saturated air supplied from the humidifier 36 to produce the humidity. The relative humidity of theinternal chamber 34 can be as saturated as possible without producing snow in theinternal chamber 34. As a non-limiting example, the relative humidity can be 90% or higher. - In
step 86, power to theelectrical component 44 is stopped and the electrical component cools down in the atmosphere with a sub-zero temperature and high humidity condition. Monitoring of the contact temperature and ambient temperature continues to be monitored during the cool down period. - In
step 88, thecontact temperature 100 and theambient temperature 102 are plotted as shown inFIGS. 8A and 8B . The freeze potential of therelay 24 is determined instep 90 by thetemperature cross-over curve 104 produced from plotting thecontact temperature 100 and theambient temperature 102 against time. If thecontact temperature 100 drops faster than theambient temperature 102, and the drop is fast enough that thecontact temperature 100 and theambient temperature 102 have acrossing point 106 on thetemperature cross-over curve 104, as shown inFIG. 8B , a high freeze potential of therelay 24 is determined. If thecontact temperature 100 and theambient temperature 102 do not cross on thetemperature cross-over curve 104, as shown inFIG. 8A , a low freeze potential of therelay 24 is determined. If therelay 24 is determined to have a high freeze potential, one or both of therelay 24 and theelectrical component 44 can be modified instep 92 to decrease the high freeze potential. - One example of an
electrical component 44 havingrelays 24 that are tested by the methods disclosed herein is a power distribution module. The power distribution module is sealed within thetest chamber 30 and connected to a vehicle 5 with awire harness 46 to power the power distribution module. The vehicle 5 is started and idled for a first period of time, simulating operation of theelectrical component 44 in a sub-zero temperature atmosphere with humidity. The first period of time can be any length of time. A non-limiting example the first period of time is a sufficient time that heats the power distribution module to operating temperature while maintaining an efficient test schedule, such as approximately ten minutes. The vehicle 5 is then turned off and the power distribution module is left un-powered to cool down for a second period of time in the same sub-zero temperature atmosphere with humidity. The second period of time can be any length of time that allows the power distribution module sufficient time to cool to atmospheric temperature, such as approximately sixty minutes. The second period of time is typically longer than the first period of time. - If the
temperature cross-over curve 104 has acrossing point 106 as inFIG. 8B , therelays 24 within the power distribution module can freeze in humid sub-zero temperature conditions. Ice builds up on thecontacts 26 of therelays 24 when the moisture vapor condenses and freezes. The ice buildup prevents closure of thecontacts 26, which prevents current flow and renders the vehicle 5 inoperable as the engine will not start. When the power distribution module is theelectrical component 44 being tested, and the problem occurs, one or both of therelays 24 and the power distribution module can be modified to prevent the ice build-up on thecontacts 26. - The modification can include one or more of removing existing heat dissipaters from the power distribution module; adding ventilation to one or both of the power distribution module and the relay; moving the relay to a different location within the power distribution module; and moving the power distribution module to a different location within an engine compartment of the vehicle. These modifications are provided as non-limiting examples. Any modification known to those skilled in the art that would achieve the desired results is contemplated herein.
- Any of the methods herein can include pre-conditioning the relay prior to simulating operation of the electrical component. The pre-conditioning can occur before temperature monitoring in the second disclosed method, but the temperatures can also be monitored during pre-conditioning.
-
FIG. 9 illustrates pre-conditioning of therelay 24. Instep 110 of pre-conditioning, therelay 24 is dried for a third period of time. The drying instep 110 can comprise operating theelectrical component 44 in a high heat and low humidity condition instep 112 and holding theelectrical component 44 in the high heat and low humidity condition in a power-off state instep 114. The drying step can take place at sufficient temperature to remove moisture from theelectrical component 44. As a non-limiting example, the drying can occur at about 100° C. and zero or low humidity. - After drying, the
relay 24 is soaked in a high temperature and high humidity condition for a fourth period of time instep 116. The high temperature and high humidity condition can occur at a temperature of about 80° C. or higher and a humidity of about 90% relative humidity or higher as a non-limiting example. The fourth period of time can be any sufficient amount of time known to those skilled in the art. As a non-limiting example, the fourth period of time is about 90 hours or greater. Therelay 24 is sealed in a sealable container within thetest chamber 30 and is then cooled from the high temperature, to room temperature, and then to a sub-zero temperature instep 118. Theelectrical component 44 can be disconnected from thewire harness 46 for this step and to achieve a tight seal within the container. When the sub-zero temperature is reached, therelay 24 is held at the sub-zero temperature for a fifth period of time in step 120. The sub-zero temperature can be as low as allowed by thetest chamber 30. In particular, the sub-zero temperature can be about −20° C. or below. The fifth period of time can be about 20 hours or greater as a non-limiting example. - When pre-conditioning is complete, the
electrical component 44 can be removed from the sealed container and reattached to thewire harness 46. Simulation of operation of theelectrical component 44 can then be initiated as disclosed in the methods herein. - The examples provided test one electrical component at a time. However, it is contemplated that a plurality of electrical components are tested at the same time, limited only by the area within the
test chamber 30. Different relays may have different temperature cross-over profiles depending on the electrical component in which the respective relay is located. When the temperature cross-over profile is created for a relay in an electrical component, the temperature cross-over profile can be used to easily test different manufacturers and different modifications to confirm a low freeze potential of the relay. - While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
Claims (15)
1. A test chamber for simulating low temperature and high humidity atmospheric conditions comprising:
a chamber with temperature control configured to control a temperature of an internal atmosphere of the chamber;
a humidifier in fluid communication with the internal atmosphere of the chamber configured to supply humidified air to the internal atmosphere; and
a sealable opening in a wall of the chamber and configured to pass a wire harness from external the chamber to inside the chamber while maintaining a sealed environment within the chamber, wherein the temperature control is configured to maintain a sub-zero temperature in the internal atmosphere while the humidifier maintains a saturated internal atmosphere.
2. The test chamber of claim 1 , wherein the temperature control is configured to produce a temperature of −20° C. or below.
3. The test chamber of claim 1 , wherein the humidifier has a controller configured to selectively control a relative humidity within the internal atmosphere.
4. The test chamber of claim 3 , wherein the controller is configured to maintain the relative humidity of the internal atmosphere at 90% or higher.
5. The test chamber of claim 1 , wherein the wire harness is connected to a power supply external to the chamber.
6. The test chamber of claim 6 , wherein the power supply is a battery of a vehicle.
7. The test chamber of claim 1 further comprising a window through which the internal atmosphere can be viewed while maintaining a sealed environment.
8. The test chamber of claim 1 further comprising sealable access ports configured to allow manipulation of an electrical component being tested within the internal atmosphere of the chamber.
9. A test chamber for simulating low temperature and high humidity atmospheric conditions comprising:
a sealable chamber having a first sealable opening configured to receive humidified air and a second sealable opening configured to receive a wire harness;
a temperature controller configured to control a temperature of an internal atmosphere of the chamber; and
a humidity controller configured to control a relative humidity of the internal atmosphere of the chamber, wherein the temperature controller is configured to maintain a sub-zero temperature in the internal atmosphere while the humidity controller is configured to maintain a saturated internal atmosphere.
10. The test chamber of claim 9 , wherein the sub-zero temperature is −20° C. or below.
11. The test chamber of claim 9 , wherein the humidity controller is configured to maintain the relative humidity of the internal atmosphere at 90% or higher.
12. The test chamber of claim 9 , wherein the wire harness is connected to a power supply external to the chamber.
13. The test chamber of claim 12 , wherein the power supply is a battery of a vehicle.
14. The test chamber of claim 9 further comprising a window through which the internal atmosphere can be viewed while maintaining a sealed environment.
15. The test chamber of claim 9 further comprising a third sealable opening configured to allow manipulation of an electrical component being tested within the internal atmosphere of the chamber.
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US13/350,056 US20130181059A1 (en) | 2012-01-13 | 2012-01-13 | Testing apparatus for preventing freezing of relays in electrical components |
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US13/350,056 US20130181059A1 (en) | 2012-01-13 | 2012-01-13 | Testing apparatus for preventing freezing of relays in electrical components |
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US13/350,056 Abandoned US20130181059A1 (en) | 2012-01-13 | 2012-01-13 | Testing apparatus for preventing freezing of relays in electrical components |
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Cited By (2)
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CN109012766A (en) * | 2018-05-17 | 2018-12-18 | 杭州伊弗欧质量检测有限公司 | High-low temperature test chamber |
CN117398901A (en) * | 2023-12-14 | 2024-01-16 | 中科赛凌(中山)科技有限公司 | Regulating and controlling protection unit for humidifying high-low temperature damp-heat test box |
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