Method of preventing or reducing water ingress into a tire inflation system

A method and system of preventing or reducing water ingress into a tire inflation system is provided.

BACKGROUND AND SUMMARY

The present application relates to a method of preventing or reducing water ingress into a tire inflation system. Tire inflation systems are utilized to adjust the tire pressure of one or more tires on a vehicle to provide the vehicle with versatility for differing terrain types or to reduce maintenance requirements. For example, a tire pressure can be decreased by a tire inflation system to provide additional traction for the vehicle and may be increased to reduce a rolling resistance of the vehicle. Further, utilizing a tire inflation system may eliminate the need to manually check the tire pressure of each tire and/or manually adjust the tire pressure when needed.

Modern tire inflation systems typically include a control unit. The control unit is provided to control the flow of air through the tire inflation system. The control unit may include a housing, which protects an electronic control portion, valves, and conduits. The control unit can be mounted on a vehicle in a location that exposes it to being submerged when the vehicle is fording a body of water such as, for example, a stream, river, or lake.

Exposure to water can damage the components of the tire inflation system located within the housing. The inventors herein have recognized the above issue as well as that it may be desirable to provide a method that prevents or reduces the chance or degree that the components of the control unit from being exposed to water when the vehicle is fording.

DETAILED DESCRIPTION

It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and methods illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise. Also, although they may not be, like elements in various embodiments may be commonly referred to with like reference numerals within this section of the application.

Referring now toFIG. 1, the method is utilized to prevent or reduce the ingress of water into a tire inflation system10. Advantageously, the method can be utilized with existing tire inflation systems. Further, the method may have applications to commercial and off-highway vehicles. Also, it would be understood by one of ordinary skill in the art that the embodiments described herein could also have industrial, locomotive, military, and aerospace applications.

Preferably, the tire inflation system10is of the central tire inflation system (CTIS) variety. The tire inflation system10can be utilized to increase or decrease the tire pressure of a tire12. As used herein, “tire pressure” refers to a pressure of air or another fluid contained within the tire. Although the tire inflation system is illustrated with only one tire12inFIG. 1, it should be appreciated that the tire inflation system10can be utilized to increase or decrease the tire pressure of a plurality of tires (not depicted), simultaneously or not.

The tire inflation system10comprises a control unit14. The control unit14includes a housing16. The housing16may be unitarily formed or comprise two or more separately formed portions. When the housing16is not unitarily formed, a seal may be provided between separately formed portions to help prevent water, dirt, and debris from entering the housing16. The housing16is utilized to protect one or more valve assemblies18,30,34,36,38,42, a pressure transducer20, and an electronic control portion22located therein. The housing16also defines a first cavity24.

The one or more valve assemblies include a first valve assembly18(hereinafter referred to as “control valve assembly”). The control valve assembly18may be of the three-way variety. Also, it is preferred that the control valve assembly18is of the solenoid variety. However, it should be understood that the control valve assembly18may be another type of valve assembly. The control valve assembly18is in fluid communication with a first fluid conduit26(hereinafter referred to as “control conduit”). The control valve assembly18can be energized and placed in an energized position by the electronic control portion22. In the energized position, the control valve assembly18facilitates fluid communication between the control conduit26and a second fluid conduit28(hereinafter referred to as “supply conduit”).

The supply conduit28is in fluid communication with the control valve assembly18and a second valve assembly30(hereinafter referred to as “supply valve assembly”). The supply conduit28is also in fluid communication with a pressurized air supply32. Preferably, the supply valve assembly30is of the solenoid variety. However, it should be appreciated that the supply valve assembly30may each be another type of valve assembly. The supply valve assembly30is in fluid communication with the pressurized air supply32and the control conduit26. The pressurized air supply32may comprise an air compressor (not depicted) and other components known in the art and is preferably attached to the vehicle.

The control conduit26is attached to and in fluid communication with the control valve assembly18, pressure transducer20, supply valve assembly 3D, and another valve assembly34(hereinafter referred to as “channel valve assembly”). The control conduit26is also attached to and in fluid communication with a deflate valve assembly36.

Preferably, the deflate valve assembly36is of the solenoid variety. However, it should be appreciated that the deflate valve assembly36may be of another type of valve assembly. The deflate valve assembly36is in fluid communication with the control conduit26and a pressure relief valve assembly38. When energized and placed in an energized position by the electronic control portion22, the deflate valve assembly36facilitates fluid communication between the control line26and the pressure relief valve assembly38.

The pressure relief valve assembly38comprises a relief valve in communication with the deflate valve assembly36and the atmosphere. The pressure relief valve assembly38is configured to be placed in an open position when a pressure in a conduit40provided between the deflate valve assembly36and the pressure relief valve assembly38is greater than a predetermined pressure. When placed in the open position, the pressure relief valve assembly38facilitates fluid communication between the control line26and the atmosphere when the deflate valve assembly36is in the energized position.

Preferably, the channel valve assembly34is of the solenoid variety. Also, it is preferred that the channel valve assembly34is of the three-way variety. However, it should be understood that the channel valve assembly34may be another type of valve assembly.

The channel valve assembly34is in fluid communication with the control valve assembly18, pressure transducer20, supply valve assembly30, and deflate valve assembly36via the control conduit26. The channel valve assembly34is also selectively in fluid communication with the tire12via a relief valve assembly42and a wheel valve44.

It should also be noted that the tire inflation system10illustrated inFIG. 1comprises only one channel valve assembly34. However, in other embodiments (not depicted), the tire inflation system may include a plurality of channel valve assemblies. In these embodiments, each channel valve assembly is in fluid communication with the control valve assembly18, pressure transducer20, supply valve assembly30, and deflate valve assembly36via the control conduit26as described above. Also, each channel valve assembly may be selectively in fluid communication with a tire or a series of tires via a relief valve assembly and one or more wheel valves.

Referring back toFIG. 1, when energized and placed in an energized position by the electronic control portion22, the channel valve assembly34facilitates fluid communication between the control conduit26and a channel conduit46. When the channel valve assembly34is in the energized position, the channel conduit46is in fluid communication with the control valve assembly18via the channel valve assembly34and the control conduit26. The channel conduit46is also in fluid communication with the relief valve assembly42. Thus, when energized, the channel valve assembly34enables fluid communication between the control valve assembly18and the relief valve assembly42. When the channel valve assembly34is de-energized and placed in a de-energized position, fluid communication between the control conduit26and a channel conduit46, which is attached to and in fluid communication with the relief valve assembly42and the channel valve assembly34, is prohibited. However, when the channel valve assembly34is de-energized and in the closed position, the channel conduit46is in fluid communication with the first cavity24via an opening48in the channel valve assembly34.

The relief valve assembly42facilitates the tire inflation system10in measuring the tire pressure, increasing the tire pressure, and decreasing the tire pressure. Also, the relief valve assembly42decreases an amount of fluid turbulence in the tire inflation system10, provides greater flexibility in configuring the tire inflation system10, and facilitates accurate control of the tire pressure of the tire12.

The relief valve assembly42is in fluid communication with the channel valve assembly34, the tire12, and the atmosphere. The relief valve assembly42is in fluid communication with the channel valve assembly34through the channel conduit46. The relief valve assembly42is in fluid communication with the tire12through an outlet conduit50and the wheel valve44. The relief valve assembly42is in fluid communication with the atmosphere through an exhaust conduit52. When the channel valve assembly34is de-energized, the exhaust conduit52is in fluid communication with the first cavity24via the channel valve assembly34, channel conduit46, and relief valve assembly42.

The pressurized air supply32is utilized to open the wheel valve44. The wheel valve44is movable from an open position to a closed position and vice versa. The wheel valve44allows the tire12to selectively communicate with the tire inflation system10via the outlet conduit50.

The electronic control portion22communicates with the control valve assembly18, pressure transducer20, supply valve assembly30, channel valve assembly34, and deflate valve assembly36. The electronic control portion22operates the tire inflation system10in response to a set of predetermined instructions, which may also be referred to as software, or in response to an instruction from an operator of the vehicle. The electronic control portion22may receive input signals from the pressure transducer20, a power supply (not depicted) and one or more additional sensors (not depicted) such as, for example, a load sensor and a speed sensor. The electronic control portion22may also receive input signals from an operator control device (not depicted). The electronic control portion22may include a microprocessor (not depicted) and a non-transitory memory (not depicted) in which programming instructions are stored. The memory can also store identification codes, tire pressure records and/or user inputs over a period of time.

The electronic control portion22outputs signals to the valve assemblies18,30,34,36. The output signals may be electrical current. Electrical current can be received by a selected valve assembly18,30,34,36to energize the valve assembly and place the valve assembly18,30,34,36into an energized position. Similarly, electrical current can be removed from a valve assembly18,30,34,36to de-energize the valve assembly and place the valve assembly18,30,34,36into a de-energized position. The electronic control portion22may also output signals to a display device (not depicted). The display device may be included as a part of the operator control device or a freestanding device.

The pressure transducer20is in fluid communication with and monitors a fluid pressure within the control conduit26. The pressure transducer20is also configured to communicate a signal relaying information about the fluid pressure within the control conduit26to the electronic control portion22.

When the control valve assembly18is energized, the pressurized air supply32is in fluid communication with the control conduit26. When the control valve assembly18is de-energized, the control conduit26is in fluid communication with the first cavity24via an opening54in the control valve assembly18. In certain embodiments when the control valve assembly18is energized, the control valve assembly18is utilized to introduce a bleed of air from the pressurized air supply32into the control conduit26. When the control valve assembly18is placed in an energized position by the electronic control portion22, the bleed of air is introduced into the control conduit26. Thus, the control valve assembly18facilitates fluid communication between the pressurized air supply32and the control conduit26. When de-energized, the control valve assembly18facilitates fluid communication between the control conduit26and the first cavity24. In this embodiment, pressurized air in the control conduit26can be directed through the control valve assembly18and into the first cavity24.

Before the vehicle fords a body of water, a fording mode can be selected for the tire inflation system10. The fording mode can be selected by a vehicle operator or another party. Selecting a fording mode, activates a fording protocol. After selecting the fording mode, the pressure in the first cavity is measured. Preferably, the pressure in the first cavity24is equal to atmospheric pressure. However, under certain conditions, such as, for example, when the vehicle is fording a body of water, the pressure in the first cavity24will be greater than atmospheric pressure.

Before measuring the pressure of the air in the first cavity, one or more pulses of air are directed to the first cavity24. Preferably, two pulses of air are directed to the first cavity24. Each pulse of air can be provided by directing pressurized air to the control conduit26. Preferably, pressurized air is directed to the control conduit by energizing the control valve assembly18. Energizing the control valve assembly18enables fluid communication between the pressurized air supply32and the control conduit26. To provide a pulse of air, it is preferred that pressurized air is directed to the control conduit26until the control conduit26reaches a predetermined pressure. In other embodiments, the control valve assembly18can be energized for a predetermined time to direct pressurized air to the control conduit26. For example, the control valve assembly18can be energized for 10 seconds. However, in other embodiments, the control valve assembly18can be energized for another predetermined period of time.

In an embodiment, the predetermined pressure is 25-50 psi. Preferably, the predetermined pressure is about 40 psi. To determine if the control conduit26has reached the predetermined pressure, the pressure in the control conduit26can be measured by the pressure transducer20. Once the air in the control conduit26is at the predetermined pressure, the control valve assembly18is de-energized. When the control valve assembly is de-energized, fluid communication between the control conduit26and the pressurized air supply32is prevented. However, de-energizing the control valve assembly18enables fluid communication between the control conduit26and the first cavity24. Once the control valve assembly is de-energized, the pressurized air in the control conduit26can be directed to the first cavity24via the opening54in the control valve assembly18. It should be noted that when providing one or more pulses of air to the first cavity24, it is preferred that the supply valve assembly30, deflate valve assembly36, and channel valve assembly34are each de-energized.

After directing the one or more pulses of air to the first cavity24, the pressure of the air in the first cavity24is measured. When the vehicle is fording a body of water, the one or more pulses of air directed to the first cavity24will increase the pressure in the first cavity24. Preferably, the one or more pulses of air increase the pressure in the first cavity24at least 0.1 psi above a recorded atmospheric pressure.

Preferably, atmospheric pressure is measured periodically by the tire inflation system10. For example, in an embodiment, atmospheric pressure may be measured every 15 minutes. After measuring the atmospheric pressure, the pressure measured is recorded. The atmospheric pressure can be measured utilizing the pressure transducer20. The pressure transducer20is in fluid communication with the atmosphere via the control conduit26, control valve assembly18, first cavity24, and the exhaust conduit52and/or a vent conduit56. It should be noted that in order to measure the atmospheric pressure, the control valve assembly18is de-energized so that the control conduit26is in fluid communication with the first cavity24.

As noted above, after directing one or more pulses of air to the first cavity24, the pressure of the air in the first cavity24is measured. In order to measure the pressure in the first cavity24, the control valve assembly18is de-energized so that the control conduit26is in fluid communication with the first cavity24. When the control valve assembly18is de-energized, the pressure transducer20can measure the pressure of the air in the first cavity24via the control conduit26and the control valve assembly18.

After measuring the pressure of the air in the first cavity24, it is determined if the pressure in the first cavity24is greater than the recorded atmospheric pressure. When the vehicle is fording, the pressure in the first cavity24increases above atmospheric pressure. For example, in certain embodiments, the pressure in the first cavity24may be 0.1-1.6 psi above atmospheric pressure. However, it should be appreciated that the pressure in the first cavity24may be another amount above atmospheric pressure. Thus, if the pressure in the first cavity24is greater than the recorded atmospheric pressure, then it is assumed that the vehicle is fording. When the vehicle is not fording, the pressure of the first cavity24may be equal to the recorded atmospheric pressure. In this embodiment, the pressurized air from the one or more pulses of air does not increase the pressure of the first cavity24because the pressurized air escapes to the atmosphere via the exhaust conduit52and/or the vent conduit56.

Unfortunately, when the vehicle is fording, water may attempt to enter the housing16via the exhaust conduit52or the vent conduit56. Advantageously, pressurized air from the one or more pulses of air can pressurize the first cavity24, exhaust conduit52, and vent conduit56to prevent or reduce water ingress into the first cavity24through the exhaust conduit52or the vent conduit56. Preferably, the pressure of the air in the first cavity24is equal to the head pressure of the water attempting to enter the housing14. It should be appreciated that when the pressure of the air in the first cavity24is equal to the head pressure of the water attempting to enter the housing14, the interface between the water and the air in the exhaust conduit52or the vent conduit56will not change. Therefore, under these conditions, water ingress into the first cavity24through the exhaust conduit52or the vent conduit56is prevented or reduced.

In embodiments where the head pressure of the water increases because, for example, the depth of the water that the vehicle is fording increases, the pressure of the air in the first cavity24will increase to be equal to the increased head pressure as additional pressurized air from the one or more pulses of air are added to the first cavity24. Increases in the pressure of the air in the first cavity24when the head pressure of the water increases enable the air to impede the movement of water into the first cavity24. In embodiments where the pressure in the first cavity24is greater than the head pressure of the water attempting to enter the housing16, the pressure of the air in the first cavity24will force any water in the exhaust conduit52and the vent conduit56out of each conduit52,56and will decrease to be equal to the head pressure of the water.

While the fording protocol is active, additional pulses of air can be provided to the first cavity24as described above. Providing additional pulses of air replaces any pressurized air that escapes during fording or adds the pressurized air to the first cavity24when the head pressure of the water increases. Additional pulses of air can be provided at predetermined time intervals. For example, a pulse of air can be provided every 15 seconds or at a different interval while the fording protocol is active. Additional pulses of air may continue to be provided even if the vehicle is turned off if the fording protocol was active when the vehicle was turned off.

In certain embodiments where the vehicle has been turned off, the fording protocol may remain active as long as the pressurized air supply is above a predetermined pressure. For example, the fording protocol may remain active as long as the pressurized air supply32is at 10 psi or more. Additionally, the fording protocol may remain active as long as the power supply has a voltage that is greater than a predetermined value. For example, the fording protocol may remain active as long as the power supply is at 20 volts or more. To end the fording protocol, the fording mode can be unselected by the vehicle operator or another party. Alternatively, the fording protocol may be terminated when the pressurized air supply is below a predetermined pressure or the power supply has a voltage that is less than a predetermined value.

Referring now toFIG. 2, an example routine is described that may be used with the system ofFIG. 1. At208, the routine determines vehicle and/or system operating conditions, which may include updating atmospheric pressure. The operating conditions may include reading the pressure sensor as described with regard toFIG. 1, which in one example may be the only pressure sensor used to determine tire pressures, atmospheric pressure, and whether increased enclosure pressure is detected as described herein. In an example, as described herein with regard toFIG. 2, the system ofFIG. 1may be put into a valve condition where the pressure sensor senses atmospheric pressure (such as all valves deactivated), and a last measured atmospheric pressure may be determined upon selection of fording mode, below, to be used as an atmospheric reference during fording for comparison against the measured enclosure pressure for control of additional air injection into the enclosure to expel water and/or reduce or eliminate water ingress into the enclosure. Further, in an example, the operating conditions determined may include a tire pressure of each tire at the current instant, such as by appropriate control of valve states as described with regard toFIG. 1. The sensed tire pressure may be adjusted based on ambient conditions, such as ambient temperature and/or ambient pressure.

Next, at210, the routine determines the vehicle operating mode. The mode may be based on current operating conditions, such as GPS navigation, or other sensors indicating whether the vehicle is currently traversing a water feature. In an example, the vehicle operator may select such a mode through a user interface of the vehicle and or a knob or other selector. Further, audio commands from the operator may also be utilized by the system to identify the operating mode of the vehicle. Various modes may be used, such as a fording mode, a non-fording mode, as well as other modes such as off-road, on-road, etc. When a mode is selected that indicates traversal of a water feature, such as fording mode, the routine carries out adjustments that may decrease potential for electronic and/or electromechanical component degradation in a system housing, such as with regard to the tire inflation system as noted herein. The adjustments may include valve adjustments, which may include open/closing one or more of the valves ofFIG. 1and/or adjusting a degree of valve opening in a range that is between fully open and fully closed, including multiple valve openings therebetween. Otherwise, when a non-fording mode is selected, the routine continues to214.

From210in the non-fording mode, the routine continues to carry out automatic tire inflation and/or deflation control. The tire pressure control may adjust the tire pressure system described inFIG. 1to maintain a desired tire pressure. The desired tire pressure may be set by predetermined values depending on a vehicle mode, which may be set by a user.

Next at214, the routine determine whether one or more of the monitored tire pressures should be adjusted based on its respective desired tire pressure, as an example. As described with regard toFIG. 1, the system may adjust valves to inflate and/or deflate one or more, or each, tire to its desired pressure at216. In this operating mode, the valves of the system ofFIG. 1are adjusted to provide desired tire pressure, such as relative to the atmospheric pressure currently sensed at208. Here, the operation of the tire inflation and/or deflation provides for movement of air through the valve and tubes as described inFIG. 1, such that potential water condensate or other water in the enclosure is cycled out of the system through the tire pressure adjustment operation, without additional air delivery to the enclosure, as compared with the fording mode discussed below.

In this way, before entering fording operation where internal pressure inside the enclosure may increase due to water pressure and water leaking into the enclosure, the system can identify a baseline atmospheric pressure for later comparison (see below).

At220, during fording operation, the system determines whether pressure in the enclosure is greater than a threshold above atmospheric pressure. The atmospheric pressure may be identified as noted above from a last measured atmospheric pressure before or upon entering fording operation. In an alternative embodiment, atmospheric pressure may be sensed from a vehicle atmospheric pressure sensor or determined from atmospheric pressure data from a navigation system, as an example. The threshold may be a fixed value or may be adjust depending on vehicle operating conditions. In an example, the pressure in the enclosure is determined in the same way atmospheric pressure is measured, but during fording the measurement is determined to indicate enclosure pressure and is compared with the last measured non-fording atmospheric pressure value to detect and reduce/eliminate water ingress.

If the answer to220is yes, the routine continues to222to adjust the valves to increase enclosure pressure. In an example, a pulse of air is provided after a predetermined time duration until such operation is discontinued, such as when exit conditions are present at224and/or the fording mode is ended by user selection of a non-fording mode.

In one example, fixed duration pulses of air may be provided. In an example, monitored conditions may decrease pulse frequency, for example in stages depending on a degree of degradation. The degradation may be indicated via a dropping battery voltage below a threshold, supply pressure dropping below a threshold, termination of engine ignition, etc. The reduced battery voltage may decrease an ability to confirm valve position control. In an example, multiple stages of reduction can be provided, such as first, highest pulse frequency upon entering the fording mode and detecting potential water ingress, then upon battery voltage and/or supply pressure dropping to first thresholds, reducing to a second, lower, pulse frequency and then upon battery voltage and/or supply pressure dropping to second thresholds, reducing to a third, lowest, pulse frequency, and then upon exit conditions stopping the pulsing of air to the enclosure altogether.

Continuing to224, the exit conditions may include one or more of the first cavity pressure returns to within a threshold of atmospheric pressure, battery voltage of the vehicle battery reaches a lower threshold, a supply pressure falls below a minimum threshold, and/or a user di sables fording operation.

Once exit conditions are met, the routine at226discontinues increasing enclosure pressure.

In an example, a method of operating an automatic tire inflation system of a vehicle, comprising: during a non-fording mode, adjusting a valve of the automatic tire inflation system to provide increase or decrease air pressure within a tire of the vehicle; and during as user-selected fording mode, providing one or more pulses of air into a control unit housing space housing valves and electronics of the automatic tire inflation system in response to a cavity pressure of the housing above a threshold. Providing pulses of air into the control unit may include adjusting a valve within the housing and the threshold may be atmospheric pressure.

From the foregoing detailed description, it will be apparent that various modifications, additions, and other alternative embodiments are possible without departing from the true scope and spirit. The embodiments discussed herein were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to use the invention in various embodiments and with various modifications as are suited to the particular use contemplated. As should be appreciated, all such modifications and variations are within the scope of the invention.