U.S. patent application number 13/350056 was filed with the patent office on 2013-07-18 for testing apparatus for preventing freezing of relays in electrical components.
This patent application is currently assigned to NISSAN NORTH AMERICA, INC.. The applicant listed for this patent is Tim Balogh, Teofil Barjuca, Jim Beach, Adrian Dobre, Ryutaro Mine, Greg Szleszynski, Adam Wehner. Invention is credited to Tim Balogh, Teofil Barjuca, Jim Beach, Adrian Dobre, Ryutaro Mine, Greg Szleszynski, Adam Wehner.
Application Number | 20130181059 13/350056 |
Document ID | / |
Family ID | 48779308 |
Filed Date | 2013-07-18 |
United States Patent
Application |
20130181059 |
Kind Code |
A1 |
Szleszynski; Greg ; et
al. |
July 18, 2013 |
TESTING APPARATUS FOR PREVENTING FREEZING OF RELAYS IN ELECTRICAL
COMPONENTS
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.
Inventors: |
Szleszynski; Greg; (Troy,
MI) ; Dobre; Adrian; (West Bloomfield, MI) ;
Barjuca; Teofil; (West Bloomfield, MI) ; Wehner;
Adam; (South Lyon, MI) ; Mine; Ryutaro;
(Farmington Hills, MI) ; Balogh; Tim; (Waterford,
MI) ; Beach; Jim; (Plymouth, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Szleszynski; Greg
Dobre; Adrian
Barjuca; Teofil
Wehner; Adam
Mine; Ryutaro
Balogh; Tim
Beach; Jim |
Troy
West Bloomfield
West Bloomfield
South Lyon
Farmington Hills
Waterford
Plymouth |
MI
MI
MI
MI
MI
MI
MI |
US
US
US
US
US
US
US |
|
|
Assignee: |
NISSAN NORTH AMERICA, INC.
Franklin
TN
|
Family ID: |
48779308 |
Appl. No.: |
13/350056 |
Filed: |
January 13, 2012 |
Current U.S.
Class: |
236/44C |
Current CPC
Class: |
B60R 16/00 20130101 |
Class at
Publication: |
236/44.C |
International
Class: |
F24F 3/14 20060101
F24F003/14 |
Claims
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.degree. 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.degree. 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.
Description
BACKGROUND
[0001] 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.
SUMMARY
[0002] 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.
[0003] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] 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:
[0005] FIG. 1 is a flow diagram of conditions within an electrical
component that can lead to the non-start condition;
[0006] FIGS. 2A and 2B are schematics of a relay in freezing
conditions;
[0007] FIG. 3 is a schematic of a test chamber for simulating
conditions to prevent freezing of relays in an electrical
component;
[0008] FIG. 4 is the schematic of the test chamber of FIG. 3 in
use;
[0009] FIG. 5 is a flow diagram of a method of preventing freezing
of relays in an electrical component;
[0010] FIG. 6 is a flow diagram of another method of preventing
freezing of relays in an electrical component;
[0011] FIG. 7 is a flow diagram of yet another method of preventing
freezing of relays in an electrical component;
[0012] FIGS. 8A and 8B depict temperature cross-over graphs;
and
[0013] FIG. 9 is a flow diagram of a pre-conditioning method that
can be used with the prevention methods disclosed herein.
DETAILED DESCRIPTION
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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 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.
[0018] 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 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.
[0019] 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.degree. C. to 110.degree. 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.
[0020] 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.
[0021] 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.
[0022] FIG. 4 is a schematic of the test chamber 30 of FIG. 3 in
operation testing an electrical component of a vehicle 5. As used
in this example, one or more relays 24 within the electrical
component 44 of a vehicle 5 are being tested. As illustrated, 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.
[0023] It is contemplated that instead of the vehicle 5, 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. It is also contemplated that the
test chamber 30 be of a sufficient size to test components while in
the vehicle 5.
[0024] 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. In step 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.
[0025] 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.
[0026] In step 58, the temperature of the internal atmosphere 34 of
the test 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.degree. C. In particular, the temperature can be
reduced to -20.degree. 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. As a
non-limiting example, the relative humidity can be 90% or
higher.
[0027] In step 62, 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. 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 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. In step
66, power is provided to the electrical component 44 for a second
time.
[0028] 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.
[0029] 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.
[0030] One example of 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. When 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.
[0031] 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.
[0032] 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. As shown in FIG. 7, 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. At the same
time, the ambient temperature within the relay 24 is monitored with
a second thermocouple in step 82. While the temperatures are being
monitored, 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.
[0033] 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. For example, the first period of time can be
approximately ten minutes.
[0034] 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.degree. C. In particular, the temperature can be reduced to
-20.degree. 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.
[0035] In 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.
[0036] In 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.
[0037] One example of 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.
[0038] If the temperature cross-over curve 104 has a crossing point
106 as in FIG. 8B, 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. When 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.
[0039] 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.
[0040] 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.
[0041] FIG. 9 illustrates pre-conditioning of the relay 24. In step
110 of pre-conditioning, 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. As a non-limiting
example, the drying can occur at about 100.degree. C. and zero or
low humidity.
[0042] After drying, 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.degree. 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. When the
sub-zero temperature is reached, 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. In particular, the sub-zero temperature can be about
-20.degree. C. or below. The fifth period of time can be about 20
hours or greater as a non-limiting example.
[0043] When pre-conditioning is complete, 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.
[0044] 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.
[0045] 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.
* * * * *