Patent ID: 12187254

DETAILED DESCRIPTION OF THE DRAWINGS

FIG.1illustrates a system diagram according to an embodiment of the present invention. The system ofFIG.1is a stand-alone implementation of the electronic trailer hand control apparatus called a Trailer Control electronic (TCe)20, in which signals from the TCe20are supplied directly to the valve controller called a Global Scalable Air Treatment (GSAT)16via a LIN bus, CAN bus, or the like. Upon receipt of the signals from the TCe20, the GSAT16converts the received signal (e.g., voltage) into an amount of air pressure to be applied to the trailer service brakes. Based on the signals from the TCe20and additional signals described below, the GSAT16determines whether to apply the brakes and, if so, how much to apply them.

The tractor-trailer braking system10according toFIG.1includes a tractor portion and a trailer portion.FIG.1primarily illustrates the tractor portion of the system, but includes elements of the trailer portion and interfaces thereto, such as the TCe20and the glad hands36. The tractor and trailer portions are pneumatically coupled to each other through the glad hands36, and the tractor and trailer communicate electronically via power line carrier communications (PLC). As illustrated inFIG.1, the system also includes various relays and modulators (“Mod”). The tractor-trailer braking system10includes reservoirs42and44that contain pressurized air for use in braking the tractor. Likewise, the trailer portion of the braking system includes one or more reservoirs that contain pressurized air for use in braking the trailer. For simplicity, this and other elements of the trailer portion of the braking system (e.g., brakes, pressure sensors, controllers, and the like) are not illustrated.

The tractor-trailer braking system10includes a foot brake valve (FBV)22, which is a mechanical valve controlled by the driver foot brake and communicates pneumatically with the reservoirs42and44. The driver depresses the FBV22when he intends to apply the service brakes of the tractor-trailer braking system10. Air from the reservoirs42and44is delivered to various braking components (e.g., brakes50-55) in order to slow down and stop the vehicle. Actuation of the FBV22will apply the service brakes on the tractor portion and the trailer portion of the tractor-trailer braking system10.

The tractor-trailer braking system10includes pressure sensors (not illustrated), which may be coupled to the FBV22to measure the pressure delivered by the FBV22when the FBV22is actuated. The pressure sensors transmit signals indicative of a foot brake application.

As described above, the tractor-trailer braking system10includes the TCe20. The driver manually actuates the TCe20when he intends to apply the service brakes of only the trailer portion of the braking system. The TCe20translates analog motion to a digital signal. The range of motion of the TCe20may be about ninety (90) degrees to allow for different gradations of braking to be requested. If only light braking is requested, the TCe20may be moved about ten (10) degrees. If full braking of the trailer service brakes is requested, the TCe20may be moved the full ninety (90) degrees. The trailer portion of the brake system may be applied via the TCe20, for example, to hold the trailer when the trailer is being coupled to the tractor and to assist preventing the vehicle from rolling backwards when stopped on a hill. In general, operation of the trailer service brakes only via the TCe20should be limited to zero or low speed maneuvers.

The tractor-trailer braking system10also includes a tractor protection valve (TPV)30that receives pressure from the FBV22or a signal from the GSAT16and transmits the service brake control pressure to the trailer portion of the braking system. The TPV30is normally mounted at the rear of the cab. The TPV30is used to protect the tractor air brake system in the event of a trailer breakaway or severe air leak. The TPV30is also used shut off air to the trailer before disconnecting the air lines.

The tractor-trailer braking system10optionally includes a display device32to communicate the status of the tractor and trailer portions of the braking system to the driver as well as any warnings related thereto. The display device32may be a lamp, indicator, audible device or a display screen in the cab of the tractor. The display device32may also communicate vehicle information to a remote location via wireless communication, such that a fleet manager will receive information about the status of the tractor-trailer braking system10. The GSAT16may include an output to control the display device32or may communicate with the display via a serial communications bus such as a LIN bus, a CAN bus or the like. Additionally, a haptic device may be coupled to the seat or steering wheel to provide the driver with haptic feedback when there is a problem with the tractor or trailer braking system.

The GSAT16includes at least one input (e.g., via CAN) to receive signals indicative of a foot brake application. The GSAT16also includes an input to receive an electronic signal from the TCe20. The signal may represent the degree of actuation and duration of actuation desired for the trailer service brakes. The GSAT16includes an air cleaning portion with a purge valve and desiccant cartridge that cleans the air, and an air distribution portion, including relay valves, pressure protection valves, switches and an ECU, which takes the clean treated air and sends it to various circuits.

The GSAT16may also include an input to receive signals from a stop lamp device (e.g., via CAN). In another example, the GSAT16may also include an input for receiving signals indicative of automated brake applications, such as from a yaw rate sensor, accelerometer (YAS), and/or driver requested brake applications.

The GSAT16includes an output to supply the TPV30. The GSAT16will supply or evacuate air in response to signals from the driver or the vehicle automated braking system.

The GSAT16includes a processor programmed to execute the functions of the GSAT described herein. The processor, which may include control logic, is programmed to receive signals from, e.g., the pressure sensors, the YAS, the stop lamp switch and the TCe20in order to control and monitor the trailer portion of the brake system. The processor may include volatile, non-volatile memory, solid state memory, flash memory, random-access memory (RAM), read-only memory (ROM), electronic erasable programmable read-only memory (EEPROM), variants of the foregoing memory types, combinations thereof, and/or any other type(s) of memory suitable for providing the described functionality and/or storing computer-executable instructions for execution by the processor. The GSAT16may control the anti-lock braking and automated braking features, such as electronic stability control and advanced cruise control with braking, of the tractor portion of the braking system.

The processor may further include a timer, which may be used for timing the length of the application of the TCe20. The processor is capable of determining and recording trailer brake applications by comparing the requests for braking of the trailer with the actual braking of the tractor. The processor will also compare the requested braking of the trailer to predetermined time periods.

In the standalone system illustrated inFIG.1, the GSAT16receives signals via CAN or LIN interface from the TCe20, processing messages from the standalone system, and thus it is less affected by outside interference, such as electromagnetic noise. Also, the GSAT16and the TCe20operate independently from the ePBC40in the standalone system. Thus, if the ePBC40is not operating correctly, the TCe20would still have the functionality to control the trailer brakes. Accordingly, the standalone system provides a lower system cost since an ePBC is not required, improved communication, and faster system response.

FIG.2illustrates a partial system diagram according to a modified version of the embodiment of the present invention illustrated inFIG.1. The arrangement inFIG.2is called a hosted implementation, in which a host electronic control unit (ECU) reads the differential signals from the TCe, interprets them, and sends the information on the serial communication bus to an ECU that has control of the air pressure system of the trailer.

The electronic signals from the TCe20are supplied to an electronic park brake controller (ePBC)40that processes the signals and subsequently provides its outputs indicating driver intent via a LIN bus, CAN bus or the like to the GSAT16for processing. The GSAT16controls the delivery and exhaust of the tractor and trailer air based, in part on the outputs received from the ePBC40. The GSAT16is used to park the tractor, the trailer, or both. Other portions of the system ofFIG.2correspond to those ofFIG.1described above, and thus are not illustrated inFIG.2or described again here. In the hosted system, a controller needs to be present in the ePBC40to interpret the signals coming from the TCe20, which saves cost on the TCe20side.

The systems according to the present invention provide low-cost solutions to detect the position of the trailer brake controller. According to one embodiment of the invention, two potentiometers70and71that change in opposite resistance values—one goes up in value while one goes down in value—are used to detect and ensure a change in position of the TCe20is correct since the two signals from the potentiometers are set up as a differential. SeeFIG.3. For example, one potentiometer can vary between 0 VDC and 5 VDC, which the other potentiometer varies from 5 VDC to 0 VDC over the range of movement of the TCe20. Alternatively, a low frequency signal (e.g., 5 kHz) and a high frequency signal (e.g., 10 kHz or 15 kHz), or signals having different duty cycles (e.g., 20% or 100%) can be used instead of the voltage to provide the differential signal for controlling the trailer service braking.

As illustrated inFIG.3, the TCe20may include the two potentiometers70and71arranged to operate in a differential configuration. The potentiometers70and71are attached to a shaft72that rotates when the handle of the TCe is moved, such that their resistances and voltages vary in a differential manner over the range of movement of the TCe20.

If additional safety is required, there can be an offset in the resistance value for one of the potentiometers. If both potentiometers are the same resistance value and have the number of turns to execute a full sweep of resistance, there will be a point in the handle position where both potentiometers read the same value. In order to correct this, one of the potentiometers can have a different resistor paired with it creating a different voltage division ratio. The microcontroller measuring the voltage will be aware of the offset and remove this value in software, thereby ensuring that both hardware signals, although different, are still related.

Diagnostics will be able to determine if the handle is shorted. When ADC=0V, the potentiometers are not connected; when ADC=VCC, and with a plausibility check, both potentiometers are operating correctly. As potentiometers are metal on metal sweeps to change resistance, it is possible a “dead zone” might occur if the TCe20is held at a constant position for elongated periods of time. If, during a TCe movement, the voltage read by the ADC is erroneous only in certain positions, it will log these and trigger a maintenance warning for a new TCe.

In an alternative embodiment, the potentiometers are replaced by a Hall effect sensing device with two magnets placed on the TCe20and two sensors placed on the opposing PCB which will track the position of the TCe20. The detected magnetic signals are used to determine the amount of movement of the TCe20in a manner corresponding to that for the two potentiometers. Alternatively, the sensing of the movement of the TCe may be performed using inductive sensing or other sensing methods.

FIG.4illustrates a method according to the present invention for ensuring proper functioning of the TCe20. The method begins in step S62with a system initialization.

In step S63, a determination is made of whether the TCe20includes a voltage offset feature. If so, step S64ensures that the offset is used properly as described above. In step S65, an initial measurement of both potentiometers70and71is taken.

In step S66, it is determined whether the measurements are correct. If the measurements are correct, then in step S67normal operation of the TCe is implemented. During normal operation, a determination is made of whether a “dead zone” is detected in step S68. If a “dead zone” is detected, the handle location of the “dead zone” is recorded and replacement of the TCe20is recommended in step S69. On the other hand, if no “dead zone” is detected, then in step S70the voltage signal is graphed to ensure that the spring return of the TCe is functioning correctly.

If in step S66it is determined that the measurements of the potentiometers are not correct, then a determination is made of whether the measured voltage is VCC. If the voltage is VCC, then the user is instructed to ensure that the TCe is connected. If the voltage is not VCC, the it is determined in step S73whether the voltage is 0V. If so, then the user is instructed in step S74to ensure that no short to ground is present.

In the case that the measured voltage is determined not to be 0V in step S73, then in step S75it is determined whether there is a mismatch on the expected voltage. If there is a mismatch, then in step S76the user is instructed to ensure that the TCe is connected properly. Also, if there is a mismatch on the expected voltage, then in step S77the user is advised to replace the TCe.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.