Electronic control module for a tire inflation system

Abstract

An inflation control module for a tire inflation system, the module having a solenoid disposed to open and close in response to one or more pressure signals.

Description

ELECTRONIC CONTROL MODULE FOR A TIRE INFLATION SYSTEMCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to US Provisional Patent Application No. 63 / 602.250 titled, "‘Electronic Control Module For A Tire Inflation System" filed November 22, 2023. The foregoing application is fully incorporated herein by reference.FIELD

[0002] The disclosed method and apparatus generally relate to electronic control modules for tire inflation systems.BACKGROUND

[0003] There exists a need for a method and apparatus to monitor the system settings of an automatic tire inflation system (ATIS), provide operational control of the ATIS, and provide system status information to the user. Such an apparatus may7be a control module that monitors pressure in the tire(s) and system while making adjustments accordingly.

[0004] A vehicle may operate in a wide range of temperature conditions, including low temperature environments. Such conditions may adversely affect the operation of various electronic components. Thus, temperature control of an electronic control module may be required for stable operation of the electronic control module.SUMMARY

[0005] An electronic control module for a vehicle tire inflation system comprising a pressurized fluid inlet and a pressurized fluid outlet; a first electron! cally-controllable solenoid valve disposed in a first path of fluid communication between the inlet and the outlet so as to selectively open or close the first path to fluid communication; and a heating element disposed in thermal communication with the solenoid valve.

[0006] An electronic control module for a vehicle tire inflation system comprising a pressurized fluid inlet and a pressurized fluid outlet; a first electron! cally-controllable solenoid valve disposed in a first path of fluid communication between the inlet and the outlet so as to selectively open or close the first path to fluid communication; and a first check valve disposed in a second path of fluid communication between the inlet and the outlet, the first check valve being normally closed and oriented so as to open the second path for one-way fluid communication by pressurized fluid from the inlet; the first path and the second path being parallel fluid paths.

[0007] A method of operating an electronic control module for a vehicle tire inflation system comprising detecting a temperature in an electronic control module: and activating a heating element in the electronic control module if the temperature is below a threshold temperature.

[0008] A method of operating an electronic control module for a vehicle tire inflation system comprising when power from a vehicle is disconnected from a battery -equipped electronic control module mounted to a trailer, using batten’ power to open a first solenoid valve to release pressurized fluid from one or more tires of the trailer; after pressurized fluid is released, when power from the vehicle is connected to the electronic control module, detecting whether pressurized fluid is entering the electronic control module; and if no pressurized fluid is entering the electronic control module, sending an alert; and if pressurized fluid is entering the electronic control module and has a pressure below a predetermined tire pressure, opening a second solenoid valve to pass air from a vehicle pressure supply to the one or more tires of the trailer.

[0009] A method of operating an electronic control module for a vehicle tire inflation system comprising receiving pressurized fluid from a pressure source; detecting a first pressure of the pressurized fluid; passing the pressurized fluid both to a first solenoid valve and to a first normally-closed one-way check valve, the first check valve being oriented to open at a first cracking pressure in response to the pressurized fluid.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates an embodiment of an electronic control module.

[0011] FIG. 2 illustrates an exploded view of the embodiment of FIG. 1.

[0012] FIG. 3 illustrates various components of an electronic control module embodiment.

[0013] FIG. 4 illustrates a section view of the embodiment of FIG. 1.

[0014] FIG. 5 illustrates a view of an embodiment of an electronic control module housing part having components assembled thereto.

[0015] FIG. 6 illustrates a view of an embodiment of an electronic control module housing part section view having components assembled thereto.

[0016] FIG. 7 illustrates a view of an embodiment of an electronic control module housing part section view having components assembled thereto.

[0017] FIG. 8 illustrates a view of an embodiment of an electronic control module housing part section view having components assembled thereto.

[0018] FIG. 9 illustrates a fluid path diagram of an embodiment of an electronic control module.

[0019] FIG. 10 illustrates an inflation fluid path diagram of the embodiment of FIG. 9.

[0020] FIG. 11 illustrates a deflation fluid path diagram of the embodiment of FIG. 9.

[0021] FIG. 12 illustrates a state diagram of the supply or inflation solenoid valve.

[0022] FIG. 13 illustrates a vehicle with an ATIS installed.

[0023] FIG. 14 illustrates a more detailed view of an installed ATIS.DETAILED DESCRIPTION

[0024] A vehicle automatic tire inflation system or ATIS may comprise a fluid pressure source, such as a fluid compressor or tank of compressed fluid such as air, in sealed fluid communication with one or more vehicle tires through a rotary union. An ATIS is typically a constant-pressure system that constantly supplies pressurized fluid to vehicle tires during operation of the vehicle to maintain tire pressure at optimal levels. An ATIS typically provides pressurized fluid to multiple tires simultaneously. In some embodiments, a pressure booster, such as a booster pump, may be used to increase the pressure of fluid from a tank of pressurized fluid before the fluid reaches the tire. An electronic control module may be used to regulate flow of fluid between the fluid pressure source and the tires.

[0025] As illustrated in FIGS. 1-3. an inflation electronic control module (ECM) 1 may in various embodiments comprise various combinations of all or some of a housing 2, electronic control board (ECB) 4, battery 6, heating pad 8, check valves 10, 32, 34, an air or fluid filter 11, shut off valve 12, one or more drain valves 14, pin connector 16, one or more exhaust ports 18. a first solenoid valve 22. a second solenoid valve 24, a first pressure sensor 26, and a second pressure sensor 28.

[0026] As illustrated in FIG. 1, an electronic control module 1 may comprise a housing 1. The housing may provide a weather-tight enclosure for electronic components. The housing may be coupled to a bracket 5 for disposition of the electronic control module on a vehicle. Pressurized fluid may be provided from a fluid pressure source (not shown) or a booster pump through a fluid conduit. Pressurized fluid may be provided to the electronic control module through a fluid conduit (not shown) coupled to the electronic control module at an inlet port 30. A shut off valve 12 may be disposed between the fluid conduit and fluid passageways in the electronic control module. The shut off valve may be, for example, a manually-operable ball valve. Pressurized fluid may be released from the electronic controlmodule to one or more vehicle tires through a delivery-side outlet port 3. The outlet port 3 may be coupled to an outlet fluid conduit (not shown) providing a path for pressurized fluid to flow to vehicle tires. As discussed in more detail below, the fluid conduit may provide fluid to one or more sealed axles, through which pressurized air may be provided to a rotary union provided at the wheel end of each axle. Pressurized fluid may flow from the rotary unions to one or more tires at the wheel ends. In other embodiments, the outlet fluid conduit may provide pressurized fluid to a booster pump, from which pressurized fluid may be provided to the one or more sealed axles.

[0027] Pressurized fluid and or condensation may be released from the electronic control module through one or more drain valves 14A and 14B. The drain valves may be manually operable or operated electronically. The drain valves can be used for maintenance purposes to drain the air tank and / or axle sides of the pneumatic system. The electronic control module may be provided with power and placed in electronic communication with other vehicle systems, such as a vehicle telematics system. In the embodiment of Fig. 1, electrical power and communication may be provided through a pin connection 16.

[0028] As illustrated in FIG. 2, a housing 2 may be provided in multiple parts that connect to one another to provide a generally sealed interior area to provide protection for electric components. In the embodiment of Fig. 2, the housing is formed of two parts 2A, 2B held together by one or more fasteners 2D, such as screws. A seal 2C may be provided at the interface of the two parts to prevent ingress of moisture into the housing. The housing may couple to a mounting bracket 5 by means of fasteners 7, such as a fastener. The bracket may then be removably mounted to a vehicle at mounting tabs 9, which may be configured to receive fasteners. In other embodiments, the bracket may be non-removably mounted to the vehicle, such as by welding or adhering the mounting tabs 9 to the vehicle.

[0029] The housing 2 may support and enclose most or all of the other components of the electronic control module 1. In some embodiments, the housing may be formed of polymer materials through common manufacturing techniques, such as injection molding, roto-molding, and additive manufacturing. In some embodiments, the housing 2 may be formed of metal, fiberglass, or other materials that can withstand vehicle travel conditions. An electrical pin connector 16 may be sealingly disposed in the housing 2 and further connected to the electronic control board. The electrical pin connector 16 may be configured to permit power and data communication with the ECM. The pin connector 16 may be, for example, an 8-pin deutsch style connector. The pin connector 16 may be a waterproof electrical connector with 8 pins: power, ground, light 1, light 2, serial 1, serial 2, extra pin 1,extra pin 2.

[0030] A supply-side drain valve 14A and a delivery-side drain valve 14B may be disposed at the housing 2. The supply-side drain valve 14A may be disposed to release or purge fluid pressure and condensate from the supply side of the ECM. The delivery -side drain valve 14B may be used to release or purge fluid pressure and condensation from the delivery side of the ECM. Delivery-side drain valve 14B may be used to deflate vehicle tires relatively rapidly from a central location. Such deflation may be desirable where some tires are over-inflated due to temperature or elevation changes. The delivery-side drain valve 14B may be opened to deflate the tires to below the desired tire pressure, then closed. Then, when the vehicle is operational, the ATIS will provide pressurized fluid to inflate the tires to the desired tire pressure.

[0031] As further illustrated in FIG. 2, disposed within the housing 2 may be an electronic control board (ECB) 4 which sen es as the central electronic circuit controlling electronic components. The ECB may be a printed circuit board having electronic components disposed on the board. The ECB may be mounted to the housing by one or more fasteners 4A. such as screws. In other embodiments, the control board may control various electronic components disposed at other parts of an automatic tire inflation system, such as at a booster pump inlet or outlet, or at a pressurized fluid supply tank. Some such components may be one or more solenoid valves, one or more pressure sensors, a telematics communication module, an accelerometer, temperature sensor, and GPS system. In some embodiments, components may be disposed at the ECB or directly connected to the ECB. For example, a battery 6 (FIG. 3) may be mounted to the ECB while the solenoid valves 22, 24 and pressure sensors 26, 28 (FIG. 8) may be in electronic communication with the ECB or directly mounted on the ECB.

[0032] The telematics communication module may allow the ECB to communicate with commercial telematics system to provide information and updates between the ECB and telematics network. The telematics communication module may communicate by any suitable wireless means, such as cellular or satellite communication. When a connection to a telematics network is not available, a vehicle fleet or maintenance yard reader may be connected to the ECB at pin connection 16 or wirelessly to upload and download data between the systems. In some embodiments, updates to the ECB software and firmware may not be implemented while the vehicle on which the ECM is installed is in motion or not parked. If the vehicle is moving (based on accelerometer signal or GPS data), then any such updates will be stored in a queue and executed when the vehicle is stopped for a determinedperiod of time.

[0033] To prevent icing of the ECM components (such as the solenoid valve) or operation of the ECM at too low a temperature, the ECM may include a heat source, such as a heating pad. In the disclosed embodiment, the heating pad provides heat to the ECM by resistance wiring. The heating pad 8 may be a silicone rubber sheet adhered to an aluminum manifold in the housing 2. A wire or wire-wound element may run through the silicone sheet in a pattern so as to provide relatively uniform heat energy throughout the housing. When provided with electrical power, the heating pad will warm the housing when a temperature sensor (not shown) in or on the ECM reads below a predetermined or selectable threshold temperature so as to maintain ECM components within operational temperature ranges. By warming the ECM. condensate in the ECM will be less likely to freeze and interfere with operation of the valves or sensors. Most commonly, moisture rushing through the solenoid when energized can rapidly form ice and prevent the solenoid from properly closing. This type of failure can be catastrophic as it may lead to the over-pressurization of tires downstream. The electronic control module uses onboard temperature sensors to control when to turn the heat pad on and off. In some embodiments, the heat pad in the electronic control module will allow safe operation down to -40deg F. Other embodiments of the heater may comprise a power resistor, ceramic heating element, or other suitable heating element.

[0034] As shown in FIG. 4, ECM may be provided with a plurality of fluid passageways for controllable communication of pressurized fluid from a fluid pressure source to one or more vehicle tires. Pressurized fluid may flow into the ECM at the fluid pressure supply port 30, and flow7into a main fluid channel 30A. A fluid filter 11 may be provided downstream of the inlet port 30 to filter out any contaminants that may have been carried to the ECM in the fluid flow from the pressurized fluid supply. In some embodiments, a normally-closed one way check valve 10 may be disposed in the main fluid channel. Check valve 10 wall open under pressure of fluid entering the main fluid channel. The check valve 10 is oriented to open under pressure of fluid entering port 30. If the fluid pressure supply loses pressure and the solenoid 22 is stuck open for some reason, the check valve 10 will close and prevent depressurization of the ECM, thereby preventing unintentional tire deflation.

[0035] The flow of fluid through the main fluid channel is controlled primarily by a supply solenoid valve 22. When open, the supply solenoid valve 22 will permit fluid flow7from the supply side port 30 to the delivery side port 3. A normally closed one way check valve 32 may be disposed in the main fluid channel and onented in the main fluid channel inthe same way as the check valve 10. When the supply solenoid valve 22 opens, pressurized fluid may flow toward the delivery side port 3. The check valve 32 will open under pressure of fluid flow from the supply side port 30.

[0036] As further shown in Figs. 2 and 4, the ECM may include one or both of the exhaust ports 18A, 18B. Each exhaust port may comprise an orifice with a normally-closed check valve and fine screen filter. A first exhaust port 18B may comprise an orifice containing a check valve 18D and fine screen filter 13B in fluid communication with the deflation segment of the air circuit thus permitting AT1S system or tire pressure to vent to atmosphere when solenoid valve 24 is opened. A second exhaust port 18A may comprise an orifice containing a check valve 18C and fine screen filter 13 A permitting fluid communication between the housing 2 interior and atmosphere to prevent pressure buildup in the housing, such as may occur due to leaks through the solenoids or sensor ports. Such fluid communication of the second exhaust port may allow depressurization of the housing 2 interior in the event of air leaks or other undesired pressure events inside of the housing. The check valves at the exhaust ports may be, for example, duckbill valves. In the disclosed embodiment, the exhaust ports 18 A. 18B may release pressurized fluid to exhaust channels 38, 39 formed in one part 2B of the housing. In other embodiments, the mounting bracket 5 may be provided with openings 5 A to correspond to the exhaust ports 18A, 18B so as to permit pressurized fluid to pass to atmosphere.

[0037] In some embodiments, such as shown in the embodiment of Fig. 4, the inflow of air may be regulated by a check valve 10 with the fluid filter 11 being disposed in the air channel as illustrated in FIG. 4. As shown in the embodiment of Fig. 8, the filter may be urged toward the inlet port 30 by a spring 15. In other embodiments, such as shown in the embodiment of Fig. 6, the filter may be configured as a check valve 10 and biased against opening except under fluid pressure and flow conditions by the spring 15.

[0038] As may be further seen in the embodiment of FIGS. 2 and 4, an exhaust solenoid valve 24 may be provided to control deflation of tires. The exhaust solenoid valve may control flow of pressurized fluid through an exhaust channel 40 in fluid communication with the main fluid channel. As may be seen in the embodiment of FIG. 4, the exhaust channel may have a normally closed one way check valve 34 disposed therein. The check valve may be oriented in the exhaust channel 40 to open under pressure from the ATIS air circuit extending from the outlet port 3 to the tires (not shown). Pressurized fluid from the tires may be communicated back toward the outlet port 3, and so into the main fluid channel. The check valve 32 and closed solenoid valve 22 will prevent pressurized fluid from the tiresfrom flowing back toward the pressurized fluid supply. Check valve 34 will open under pressure from fluid from the tires. However, the exhaust solenoid valve 24 will remain closed to prevent escape of pressurized fluid to atmosphere until opened. The exhaust solenoid valve will control flow of pressurized fluid from the exhaust channel to the exhaust port 18B. When the exhaust solenoid valve opens, then pressurized fluid may escape to atmosphere through the exhaust port 18B, thereby deflating the vehicle tires having pressure controlled by the ECM. Deflation may be desired, for example, to correct temperature- or elevation-induced overinflation.

[0039] As may be seen in the embodiment of Fig. 5, one part 2B of the housing may be provided with orifices 45, 46 that permit fluid communication between the main fluid channel 30A and pressure sensors 26, 28. The part 2B of the housing may be further provided with orifices 47, 48 between the main fluid channel 30A and the solenoid 22. The part 2B of the housing may be further provided with orifice 49 between the exhaust channel 40 and the solenoid 24, and orifice 50 between the solenoid 24 and the exhaust port 18B. The part 2B of the housing may be further provided with orifice 51 between interior of the housing and the exhaust port 18A.

[0040] As may be seen in the embodiment of Fig. 6, the check valve 32 may be positioned in the main fluid channel 30A between orifice 47 and orifice 48. That is, the ATIS air circuit through the ECM provides parallel fluid paths, with one fluid path being provided through the check valve 32 and the parallel second fluid path being provided through the solenoid valve 22. The term ‘parallel’ does not necessarily mean that the fluid channels for the fluid paths are physically parallel to each other; rather, the term is intended to make clear that the first and second fluid paths are not in series or sequential, i.e., fluid may flow through either or both fluid paths to reach a common point. Thus, when the solenoid valve 22 is closed, pressurized fluid may flow from inlet port 30 to outlet port 3 through the check valve 32. When the solenoid valve 22 is open, pressurized fluid may flow from inlet port 30 to outlet port 3 through the check valve 32 and through the solenoid valve 22.

[0041] As may be further understood from the embodiment of Fig. 6, when solenoid valve 24 is closed, pressurized fluid may not flow from the orifice 49 to the orifice 50. When solenoid valve 24 is open, pressurized fluid may flow from the orifice 49 to the orifice 50, and so to the exhaust port 18B.

[0042] As may be seen in the embodiment of Fig. 7. the solenoid valves 22, 24 may be connected to the ECB circuitry through pin connections 22A, 24A.

[0043] As shown in FIG. 8, a first supply-side pressure sensor 26 may monitorsupply-side air pressure while a second delivery-side pressure sensor 28 monitors axle or tire pressure (depending on the style of ATIS). The ECM may use data or signals from the pressure sensors 26, 28 to control the opening and closing of a first and second solenoid valves 22, 24.

[0044] During inflation operation, the ECM may provide two inflation pathways so as to protect operation of solenoid 22. The first path may be through first check valve 32 in parallel with a second path through the first solenoid valve 22. The check valve 32 may have a predetermined or adjustable cracking pressure, and will open at specific or selected pressure differential between pressure supply and outlet port 3. For example, if the cracking pressure is about 70psi and the pressure supply provides pressurized fluid at 120psi, then the pressure supply may provide pressurized fluid through the check valve 32 if the outlet port 3 pressure is below 50psi (which outlet port 3 pressure should be approximately the same as axle or tire pressure, depending on the style of ATIS). Check valve 32 actuation or opening allows the downstream components (an axle, tire, or other pressure vessel) to pressurize until the fluid pressure at the check valve 32 inlet and the fluid pressure at the check valve 32 outlet are both within the operating pressure range of the inflation solenoid valve 22. For example, if supply pressure is at 120psi and the check valve opens at 70psi (cracking pressure of 70psi), then said check valve will pressurize the downstream target until it reaches 50psi and thus the solenoid valve will not need to operate at a pressure differential greater than 70psi or whatever the pressure differential is across the check valve 32. The inflation fluid circuit may be operate in a completely unpowered state so that tire pressure will not fall below a certain level even if all vehicle power is lost. That is, inflation operation may be entirely mechanical by permitting pressurized fluid to flow' through the check valve 32 if the ECM loses electrical power. If an electronic failure occurs, the ECM is still able to provide automatic tire inflation capabilities at a reduced performance.

[0045] If the pressure differential exceeds the threshold pressure of the check valve 32 fluid circuit, then ECM may open the first solenoid valve 22 to increase the flow' volume. That is. if the check valve 32 is open but not filling the tires quickly enough, then the solenoid valve 22 may open to provide fluid flow through the solenoid valve fluid path simultaneously with fluid flow- through the check valve 32 fluid path. If the check valve 32 is closed because the pressure differential between the fluid pressure at the check valve 32 inlet and the fluid pressure at the check valve 32 outlet is below' the cracking or opening pressure of the check valve 32, then the ECM control circuitry (ECB controller) may send an open signal to the open the solenoid 22, thereby allowing pressurized fluid to flow from thepressure supply to the tires until the tire pressure approximately equals the supply pressure.

[0046] During all inflation operations, the second exhaust solenoid valve 24 will remain in the closed position to isolate the pressurized fluid circuits from the atmosphere. In some embodiments, the deflation or exhaust solenoid valve 24 may only open when there is a particular pressure differential between the system and atmosphere. Thus the axle / tire side may never be deflated lower than the opening or cracking pressure of the check valve 34 even if the second solenoid 24 were to fail or stick in the open position. In some embodiments, the check valve 34 may have a cracking pressure set at 3-10 psi higher than the supply pressure to prevent tire pressure from falling below optimal tire pressures. In other embodiments, the check valve 34 may have a cracking pressure at or below the supply pressure, thus allowing the solenoid 24 to better control deflation so as to reduce tire over-pressurization risk.

[0047] During deflation operations, the supply solenoid valve 22 is in the closed position while fluid flow from outlet port 3 to inlet port 30 is stopped in the main fluid channel 30A by the first check valve 32. The exhaust solenoid valve 24 may open to atmosphere and vent over-pressurization of the axle / tire end of the circuit. The second check valve 34 may be in series with and upstream the second solenoid valve 24 so as to ensure that there is only air flow out of the ATIS system and no backflow from the atmosphere or vehicle environment into the ATIS. Deflation may occur when the ECB reads a tire / axle pressure at a threshold value above the desired pressure. Such a threshold may be, for example, 10% above desired pressure. Desired pressure and the threshold value may be adjusted through the telematics system or a yard reader.

[0048] A battery 6 may allow for electronic signals, such as those to communicate alerts and data, to be sent when there is no vehicle power available. The batter 6 may be, for example, a CR123 battery. A lack of power may include disconnection of the ECM from the vehicle power (such as when a trailer to which the ECM is mounted is disconnected from a truck) or a power failure of the power-supplying vehicle. In some embodiments, the battery may provide sufficient power to deflate axle pressure using the deflation solenoid 24 after trailer has stopped moving and AUX power has been disconnected from ECM for a period of time. In some embodiments, the battery may provide power sufficient to periodically send ECM information to a telematics gateway when unhooked from main power source. In some embodiments, the battery may provide power sufficient to send a “no AUX power” alert if the trailer is moving (based on accelerometer signal or GPS data) and no AUX power is detected by the ECM. In some embodiments, the battery may provide power sufficient to send a “AUX power short” alert if the trailer is moving and an AUX power short is sensed bythe ECM.

[0049] Fig. 9 illustrates an embodiment of the ECM fluid circuit. The fluid path starts at the power supply, passes through an optional manual shut-off valve 12, communicates with a supply-side pressure sensor 26, then branches into parallel fluid paths at junction 30X, one being a path through the solenoid valve 22 and the other being a path through the check valve 32. The parallel fluid paths then re-join at junction 30Y and branch again at junction 30Z. One branch of the path is exhaust channel 40, and the other branch of the path communicates with delivery-side pressure sensor 28 and continues to a pressurized axle or tires.

[0050] Fig. 10 shows the ECM fluid circuit during inflation. During inflation, as indicated by the arrow and heavier lines, fluid may flow from the supply into the ECM through the shut-off valve 12, pass through either or both of the solenoid valve 22 and check valve 32. The fluid may pass into the exhaust channel 40, depending on the placement and cracking pressure of the check valve 34, and stop at the closed solenoid valve 24. The fluid may also continue to the tires.

[0051] Fig. 11 shows the ECM fluid circuit during deflation. During deflation, as indicated by the arrow and heavier lines, fluid may flow from the tires into the ECM. The fluid is stopped by closed solenoid valve 22 and check valve 32. Solenoid valve 24 is open to permit fluid to flow to atmosphere. In some embodiments, the check valve 34 opens when the difference between axle and atmosphere is greater than 70psi. This valve acts as a safety valve and will only allow a deflation solenoid that fails in the energized state to remove enough air to drop the axle pressure to 70psi.

[0052] Fig. 12 provides a state diagram of the inflation and deflation circuits. In some embodiments, when the ECM first powers on, the solenoid valves 22, 24 are closed. The solenoid valve 22 will not open unless the voltage to the ECM is equal to or greater than a set minimum voltage, e.g., 10V; the temperature inside the ECM must be equal to or greater than a set minimum threshold temperature; the tire / axle pressure must be lower than the desired or set tire pressure and lower than the supply pressure; and deflation solenoid valve 24 is closed. In some embodiments, the solenoid valve 22 will remain open while these conditions are satisfied and will close at the failure of any one of the said conditions. In some embodiments, the desired tire pressure may be the same as the supply pressure. That is, the desired tire pressure may not be programmed into the ECM, but set at the pressure supply, such as by an adjustable pressure regulator at a pressure tank or booster pump output pressure setting.

[0053] The control algorithm of the ECM may utilize a corrected pressure valueduring operations rather than constantly opening and closing the air flow to take spot readings on the tire pressure. Corrections may be required to account for any back pressure generated or other such fluid dynamic phenomena that may occur in the fluid transfer. In some embodiments, the pressure sensors 26, 28 may most accurately measure fluid pressure when the fluid is static or moving slowly. When the fluid moves more quickly, such as during an inflation event, the pressure sensors 26, 28 may not correctly indicate pressure in the main fluid channel 30A due to the configuration of the fluid channels (e.g.. varying diameters, lengths and branching). The correction formula may be normalized for the particular physical characteristics of the fluid transfer channels deployed between components of the ATIS in use.

[0054] Thus, for example, when air is moving across the pressure sensor 28 in a dynamic fashion, it can distort the pressure reading. The length and diameter (such as 14” DOT) of the tubing that is plumbed in between the ECB and the axle also can cause a skewed sensor reading. As air is moving through the system and out through the tubing (such as 14” DOT tubing), back pressure is created because of the smaller inside diameter of the DOT tubing compared to the diameter of the main fluid channel 30A. This back pressure can cause the pressure sensor on the ECB to read higher than the actual pressure inside the axle during inflation. Once inflation stops, the pressure sensor 28 on the ECB can accurately reads the pressure of the axle.

[0055] A corrected pressure value may be obtained using the following equation:PA= PD - 0.32(PS-PD)-0.4 where PA = actual pressure, Ps = supply pressure (air tank or booster pump), PD = deliver}' pressure (axle or tire).

[0056] This equation is normalized to work with 15ft of !4” DOT tubing in between the ECB and the axle. The equation may be normalized to work with other tubing lengths and fluid channel configurations, and the ECB programmed accordingly.

[0057] The ECM may utilize a dynamic control algorithm wherein if the ECM determines inflation is not occurring at a satisfactory' rate, then the fill rate may be adjusted. Fill rates may be calculated using the following equations: a. VA = (PA + 14.7)*( VAA / 14.7) b. VD = (PDE + 14.7)*( VAA / 14.7) c. (VD- VA) / (Ps - PA)*C = TPs = supply pressure T = timePA = axle pressure C = constantPDE = desired pressure VA = pressurized axle volumeVAA = atmospheric axle volume VD = desired pressurized axle volume 14.7psi = atmospheric pressure

[0058] In other embodiments the ECM may use a static algorithm to determine inflation rates and times in which the algorithm is optimized for the smallest axle in current use. A static algorithm optimized for the smallest commercial axles will work with all other larger axle configurations, but fill times will not be as efficient. Alternatively, the static algorithm may be a unique algorithm for particular vehicle setups, such a certain brand of axle deployed in a particular configuration (single, tandem, tri, etc). In some embodiments, these static algorithms may be modified by an operator through the telematics system or a yard reader.

[0059] Furthermore, the ECM may determine whether a tire is leaking based on the change in pressure seen on the delivery side over a period of time. For example:

[0060] Scenario 1: Delivery side sensor sees value 10% below the desired pressure. However, all of the tires are at the proper desired pressure. This means that only the axle volume is below the desired pressure. Based on the algorithm, the ECM will determine the length of time to open the solenoid to properly pressurize the axle; say 10 seconds. After the solenoid is opened for 10 seconds, the delivery side sensor now reads the proper desired pressure, and the axle and tires are all properly pressurized.

[0061] Scenario 2: Delivery side sensor sees value 10% below the desired pressure. In this case, one tire is 10% under pressure along with the axle that is directly coupled to it. Based on the algorithm, the ECB will determine the length of time to open the solenoid to properly pressurize the axle; say 10 seconds. After the solenoid is opened for 10 seconds, the delivery' side sensor only shows an increase of 2%. Since opening the solenoid for 10 seconds did not bring the delivery’ side sensor reading close to the desired pressure, the ECB is able to determine that a tire is also low in pressure. The ECB will now adjust its fill times to run a "tire fill" routine.

[0062] For all static and dy namic algorithms, the ECM will fill up axle / tires when the delivery' side sensor reads below the desired pressure. Supply side pressure sensor must read higher than the delivery side sensor or else the inflation solenoid valve 22 will remain closed.

[0063] In some embodiments, the ECM starts by running a “conservative” static algorithm. If the ECM detects from the change in pressure that the tires are not filling as quickly as desired or intended, the ECM may dynamically adjust its equation to better fit its paired trailer.

[0064] The ECM is equipped with the technology to perform a startup diagnostic testensuring proper ATIS functionality every time the trailer hits the road. To run this test, the trailer must initially start in a state of needing to inflate the tires or pressurize the axles, depending on ATIS type. If the ECM sees that the axle or tires needs to be pressurized inflated, it will open the inflation solenoid valve 22 to add air. If no air is detected as being added (e.g., insufficient or no pressure from the inlet port 30, then the ECM detects that it is not working properly. One example of such failure could be that the manual ball valve is closed. The ECM will then notify the driver through the trailer’s mounted warning light and through a telematic alert. To ensure the trailer is always initially in a state of needing to inflate the axle, a deflation solenoid, accelerometer, and on-board battery7are provided. For example, the ECM detects when the vehicle is driving dow n the road by signal from the accelerometer and determines that it is receiving approximately 12V from the tractor. The ECM determines when the trailer on which it is mounted has been parked and unhooked from the tractor because the accelerometer shows no movement, and the ECM determines that tractor power has been removed. After the prerequisites are met, the ECM will utilize the onboard battery7to pow er the deflation solenoid 24 which will then remove a controlled amount of air from the axle or tires(depressurizing by approximately 5-10psi). When the trailer is hooked back up, the ECM will see that the axle is below the desired pressure and attempt to fill, thus performing the diagnostic test.

[0065] The ECM may also enable a diagnostic test to be performed before moving the vehicle. Through the accelerometer, the ECM may determine if the vehicle is in motion. The motion state combined with whether the ATIS and ECM are being pow ered by vehicle or local pow er (the battery ) allows the ECM to determine a parked state versus a stop in travel. The ECM may require the vehicle to start in a slightly deflated state so as to ensure the system has an inflation event to monitor at start up. Thus, the ECM may open the deflation circuit upon parked state conditions being met and bleed a small amount of pressure from the tire / axle. Upon non-parked state conditions being met, the ECM will attempt an inflation event and if such an event does not occur then the ECM can alert the user.

[0066] An alert feature may include a visual alert and a telematic alert. Other communicative methods may also be employed such as aural signals. Visual alerts may be provided by a signal lamp disposed such the driver may see the lamp without interfering with safe driving practices. For example, a lamp may be disposed on the driver’s side of a trailer such that the lamp is visible in the driver’s mirror at all times. Other locations for a lamp may also be suitable, such as in the cab of a tractor. A lamp may be dual colored so as to easilyclassify the type of problem being communicated. For example, white light may indicate an ATIS operational alert while amber light may indicate a system error such loss of connectivity or other component related error. Other alerts pertaining to the ATIS operation are also possible, including lack of proper function by the ATIS / ECM components.

[0067] An ATIS alert may be signaled through white light on the lamp to indicate issues such the tire / axle pressure being below a threshold value for a set period of time while the vehicle is motion. The ECM would trigger this white light signal for a specified time limit. This alert may be repeated at a set cycle rate until the issue is resolved or other intervention is employed. Another alert might be that the inflation solenoid has been open for an extended period of time and thus a serious leak in the tire is present.

[0068] During startup, the ECM may transmit a series of codes through the lamp to indicate system status. For example, a solid amber light may illuminate upon startup. This indicates both solenoid valves are closed, and the initialization test mentioned prior is being performed. The amber light may stay illuminated as the test is completed and if the expected conditions and actions are not found during initialization. That is. the amber light will remain on until supply side pressure sensor reads at or above desired pressure. If supply side pressure sensor never detects a value above the desired pressure, then the ECM concludes that the manual shut off valve is closed, or there is an issue with the pressure supply. If supply side pressure sensor detects a value above the desired pressure, and the axle pressure is lower than the desired pressure, a short fill time test will be run to determine if the inlet manual shut off valve is opened. If inlet manual shut off valve is closed, then the amber light will remain on. If the initialization test is completed and passed, then the amber light may blink three times and turn off to indicate a successful test and startup.

[0069] Generally, for some embodiments of warning light operation, the warning light will remain off unless the following conditions are met: the vehicle is driving and delivery pressure reads a value at least 10% below" the desired pressure for X period of time (light to remain on a minimum of X minutes); if the inflation solenoid has been opened for X amount of time over the past X amount of minutes; and the ECM determines that solenoids are not firing properly and / or pressure sensors are not reading properly.

[0070] Generally, for some embodiments of deflation solenoid operation, the solenoid valve 24 on the delivery side can open and exhaust excess delivery pressure to atmosphere; the deflation solenoid 24 open when the delivery' side sensor reads a value at least 10% above the desired pressure; the deflation solenoid acts in conjunction with the accelerometer and rechargeable battery to drain axle pressure once trailer has stopped and been uncoupled frompower. This will ensure that the ECM can run a functional "start up” test as described above.

[0071] As may be seen in FIG. 13. a vehicle 900 may comprise a truck 902 and a trailer 904. The truck 902 may include one or more drive axles 906 as part of the vehicle's powertrain. The truck 902 may further include a steer axle (not shown in detail) having pivotable spindles that may provide steering capability for the vehicle 900. The trailer 904 may include one or more fixed axles (not shown). Each axle may have one or more wheels 908 mounted thereto. A pneumatic tire 910 may be mounted to each wheel 908. Each axle may have two or more tires attached at each end of the axle, such as the set of two tires 910 (dual tires) on each end of the trailer axle and drive axle 906 show n in FIG. 13.

[0072] In some embodiments, the vehicle 900 may be provided with tire pressure equalization system that maintains each set of dual tires 910 at a substantially equal air pressure. The tire pressure equalization system may be used to equalize air pressure between each tire of the dual tire set 910. As shown in FIG. 13, the tire pressure equalization system may include air hoses 912 in fluid communication with each tire of the set 910 for communicating air between the tires of the dual tire set 910. Such systems may equalize tire pressure, via a set of tire pressure equalization valves mounted at the wheel end.

[0073] In some embodiments, the vehicle 900 may be further provided with an automatic tire inflation system (ATIS) that uses pressurized air from the vehicle's air brake system or some other source of pressurized air to maintain the tires 910 at a desired air pressure. The automatic tire inflation system may be used to control air pressure in one or more of the tires 910 mounted to the steer axle (not shown), drive axle 906 or trailer axles (not shown). As shown in FIG. 13, the automatic tire inflation system may include one or more air hoses 912 in fluid communication with each tire 910 for communicating air from an air pressure source 914 to and from one or more of the tires 910. Such systems may supply pressurized air, via a rotary union mounted on or in the wheel-end assembly, to the tires 910 so as to pressurize the tires 910. Such systems may route air through hoses positioned external to the vehicle, or route air through a sealed or unsealed axle. Such systems may be used to inflate trailer tires 910. and / or tires 910 mounted to the steer axles or drive axles 906 of a heavy truck. As described in more detail below, a tire pressure equalization system may be used with or without an automatic tire inflation system.

[0074] FIG. 14 illustrates an embodiment of an automatic tire inflation system that may be used with a tire pressure equalization system. A trailer 904 may include two axles 702 and 204. Dual tires 206 and 208 are mounted at each end of the axles 702 and 204. In some embodiments, a single tire may be mounted at the end of each axle 702, 204, instead ofdual tires. The automatic tire inflation system may generally include an ECM 214 and one or more rotary’ air connections or rotary air connections 216 and 218 mounted in or near the axle ends. The ECM 214 may receive pressurized air from an air pressure source 914 through a conduit 712. The air pressure source 914 may comprise, for example, a vehicle air brake system air supply, or a step-up or booster pump. The ECM 214 may control or reduce (such as by a pressure regulator) the air pressure from the air pressure source 914 to an air pressure level suitable for inflating the tires 206, 208, 910, such as, for example, at 110 or 120 psi. Pressurized air may flow from the ECM 214 through air conduits 222 and 228 to the axles 702 and 204.

[0075] The axles 702 and 204 may be wholly or partially solid or hollow and may be configured in a variety of ways. For illustration purposes only, axles 702 and 204 are shown as hollow and sealed to contain pressurized fluid, such as air or nitrogen. For example, in some embodiments, an axle may comprise a solid beam having a spindle attached to each end (not shown). The axle spindles may be configured to allow mounting of wheel bearings upon which a hub may be rotatably mounted (not shown). In other embodiments, an axle may comprise a hollow tube having a spindle attached to each end. The spindles may be hollow, resulting in a hollow axle that is open at each end. Alternatively, the spindles may be wholly or partially solid, resulting in a hollow axle that is closed at each end.

[0076] If the axle is open at the end, the axle may be sealed so as to allow the hollow axle to hold pressurized air and to support air conduits or rotary air connections (or components thereof). The open end may also be provided with a plug or cap that may serve more to support air conduits or rotary air connections (or components thereof) than to seal the hollow axle to hold pressurized air.

[0077] In the embodiment of FIG. 14, axles 702 and 204 may be hollow sealed axles. In one embodiment, axle 204 may be hollow and may be sealed to serve as part of the conduit 222 for pressurized air. The air conduit 222 may be sealingly connected to the axle 204 to allow pressurized air to flow from the ECM 214 to the axle 204. The pressurized air may flow through the axle 204 to a rotary air connection 216 mounted in or near the spindle end as described in more detail below. An air hose 912 may connect to the rotary air connection 216 to a valve stem 221 of the wheel 209 to which the first tire 208 is mounted, thus allowing pressurized air to flow to and / or from the tire 208. Another air hose may connect to the rotary air connection 216 to a valve stem of an adjacent wheel (not shown) to which a second tire is mounted, thus allowing pressurized air to flow to and / or from the tire 208.

[0078] In some embodiments, the air conduit 222 may be sealingly connected to a tee226 to allow pressurized air to flow both to axle 702 and to axle 204. An air conduit 228 may, for example, allow pressurized air to flow from the tee 226 to a conduit 230 disposed in axle 702. Axle 702 may carry an air conduit 230 to communicate pressurized air to rotary air connection 218. Air hoses 912, 232 may connect the rotary air connection 218 to the valve stems 219 of the wheels to which tires 206 and 208 are mounted, thus allowing pressurized air to flow to and / or from the tires 206 and 208. In other embodiments, if the axle 702 is solid, then a channel may be bored in axle 702 to permit positioning of all or part of conduit 230 inside the axle 702.

[0079] In some embodiments, the ECM may be provided in multiple housings, e.g, the inflation fluid circuit of solenoid 22 and check valve 32 may be provided in one ECM housing, and the deflation fluid circuit of deflation solenoid 24 may be provided in a separate ECM housing remote from the inflation fluid circuit. In some embodiments, an ECM may comprise only an inflation solenoid valve 22 and check valve 32 provided in parallel fluid paths. In some embodiments, an ECM may comprise only an inflation solenoid and check valve provided in parallel fluid paths, and a pressure sensor. In some embodiments, an ECM may comprise a solenoid valve and a heating element disposed so as to control the temperature of the solenoid valve.

[0080] In some embodiments, ECM housings or components may be placed at the inlet or outlet of a booster pump. For example, a booster pump may be disposed in a fluid path between a pressure source and inflation solenoid so as to receive pressurized fluid from the pressure source and provide fluid at a higher pressure to the inflation solenoid. In some embodiments, a booster pump may be disposed in a fluid path between an inflation solenoid and a tire so as to receive pressurized fluid from the inflation solenoid and provide fluid at a higher pressure to the tire. For example, a booster pump may be disposed in a fluid path between a pressure source and normally-closed one-way check valve so as to receive pressurized fluid from the pressure source and provide fluid at a higher pressure to the normally-closed one-way check valve. In some embodiments, a booster pump may be disposed in a fluid path between an normally-closed one-way check valve and a tire so as to receive pressurized fluid from the normally-closed one-way check valve and provide fluid at a higher pressure to the tire. For example, a booster pump may be disposed in a fluid path between a pressure source, and an inflation solenoid and normally-closed one-way check valve, so as to receive pressurized fluid from the pressure source and provide fluid at a higher pressure simultaneously to the inflation solenoid and normally-closed one-way check valve. In some embodiments, a booster pump may be disposed in a fluid path between an inflationsolenoid and normally-closed one-way check valve, and a tire so as to receive pressurized fluid from the inflation solenoid or normally-closed one-way check valve, or simultaneously from both, and provide fluid at a higher pressure to the tire.

[0081] Although the disclosed subject matter and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims. Moreover, the scope of the claimed subject matter is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition, or matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods or steps.

Claims

CLAIMSWhat is claimed is:

1. An electronic control module for a vehicle tire inflation system comprising: a pressurized fluid inlet and a pressurized fluid outlet; a first electronically-controllable solenoid valve disposed in a first path of fluid communication between the inlet and the outlet so as to selectively open or close the first path to fluid communication; and a heating element disposed in thermal communication with the solenoid valve.

2. The electronic control module of claim 1, further comprising a first pressure sensor disposed so as to detect a first pressure of fluid at the inlet and provide a first pressure signal for control of the first solenoid valve.

3. The electronic control module of claim 2, further comprising a first check valve disposed in a second path of fluid communication between the inlet and the outlet, the first check valve being normally closed and oriented so as to open the second path for one-way fluid communication from the inlet to the outlet; the first path and the second path being parallel fluid paths.

4. The electronic control module of claim 3, further comprising a second electronically-controllable solenoid valve disposed in a third path of fluid communication so as to selectively open or close the third path to fluid communication between the first solenoid valve and atmosphere, and between the first check valve and atmosphere.

5. The electronic control module of claim 4, further comprising a second pressure sensor disposed so as to detect a second pressure of fluid at the outlet and provide a second pressure signal for control of the first solenoid valve and / or the second solenoid valve.

6. The electronic control module of claim 5, further comprising a second check valve disposed in the third path of fluid communication between first solenoid valve and the second solenoid valve, the second check valve being normally closed and oriented so as to open the third path for one-way fluid communication to the second solenoid valve.

7. An electronic control module for a vehicle tire inflation system comprising: a pressurized fluid inlet and a pressurized fluid outlet; a first electronically-controllable solenoid valve disposed in a first path of fluidcommunication between the inlet and the outlet so as to selectively open or close the first path to fluid communication; and a first check valve disposed in a second path of fluid communication between the inlet and the outlet, the first check valve being normally closed and oriented so as to open the second path for one-way fluid communication by pressurized fluid from the inlet; the first path and the second path being parallel fluid paths.

8. The electronic control module of claim 7, further comprising a first pressure sensor disposed so as to detect a first pressure of fluid at the inlet and provide a first pressure signal for control of the first solenoid valve.

9. The electronic control module of claim 8, further comprising a second electronically-controllable solenoid valve disposed in a third path of fluid communication so as to selectively open or close the third path to fluid communication between the first solenoid valve and atmosphere, and between the first check valve and atmosphere.

10. The electronic control module of claim 9, further comprising a second pressure sensor disposed so as to detect a second pressure of fluid at the outlet and provide a second pressure signal for control of the first solenoid valve and / or the second solenoid valve.

11. The electronic control module of claim 10. further comprising a second check valve disposed in the third path of fluid communication between first solenoid valve and the second solenoid valve, the second check valve being normally closed and oriented so as to open the third path for one-way fluid communication to the second solenoid valve.

12. A method of operating an electronic control module for a vehicle tire inflation system comprising: detecting a temperature in an electronic control module; and activating a heating element in the electronic control module if the temperature is below a threshold temperature.

13. A method of operating an electronic control module for a vehicle tire inflation system comprising: when power from a vehicle is disconnected from a battery -equipped electronic control module mounted to a trailer, using battery power to open a first solenoid valve to release pressurized fluid from one or more tires of the trailer;after pressurized fluid is released, when power from the vehicle is connected to the electronic control module, detecting whether pressurized fluid is entering the electronic control module; and if no pressurized fluid is entering the electronic control module, sending an alert; and if pressurized fluid is entering the electronic control module and has a pressure below a predetermined tire pressure, opening a second solenoid valve to pass air from a vehicle pressure supply to the one or more tires of the trailer.

14. A method of operating an electronic control module for a vehicle tire inflation system comprising: receiving pressurized fluid from a pressure source; detecting a first pressure of the pressurized fluid; passing the pressurized fluid both to a first solenoid valve and to a first normally- closed one-way check valve, the first check valve being oriented to open at a first cracking pressure in response to the pressurized fluid.

15. The method of claim 14, further comprising: passing the pressurized fluid through the first check valve if the pressure difference across the first check valve is greater than the first cracking pressure; detecting a second pressure of fluid passed through the first check valve; and opening the first solenoid valve if the second pressure is equal to or more than the first cracking pressure and the second pressure is less than a predetermined tire pressure.

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