JP4427803B2 - Vehicle submersion detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle submergence detection device capable of early and securely detecting submergence of a vehicle without separately providing a sensor for submergence detection (water sensor etc.). <P>SOLUTION: In the vehicle K1 having a TPMS including a radio communication means between a vehicle body and a tire, the communication state between the vehicle body and the tire is monitored by a controller 1 (submergence determination means) of the TPMS. On the condition that the state where the communication is impossible has been continued for set time or longer or set frequencies or more, it is determined that submergence of the vehicle occurs. Thus, submergence of the vehicle can be early and securely detected. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a technique for detecting submergence of a vehicle for the purpose of, for example, realizing a function of a power window of a vehicle (particularly, a window opening operation for a passenger to escape from the vehicle) with high reliability.

2. Description of the Related Art In recent years, in a vehicle power window system, a configuration in which a submersion of a host vehicle is detected and a special submergence countermeasure is executed by a control circuit has been widespread in order to ensure the ease of occupant escape when submerged.
For example, in Patent Document 1, in order to solve the problem that the window operates freely when submerged, a sensor (such as a submergence detection gap) that detects water and detects submersion is provided in the control box of the power window system. A technique is disclosed in which, when submergence is detected, both bidirectional relays that drive the window motor in each direction are simultaneously turned on to connect both terminals of the motor coil to the power supply line.

  In Patent Document 2, a switching element (transistor) or a switch contact is provided on both sides of a relay coil in order to ensure that the window can be operated reliably (at least in the opening direction) when submerged. An apparatus is disclosed that reliably drives only a predetermined relay coil when both sides of one relay coil corresponding to the operation direction are turned on synchronously during operation. Since this device does not have a function to detect whether or not it is submerged, it can only be operated in a specified direction (for example, the opening direction of the window) when submerged, and other operations are prohibited or submerged. Inundation countermeasures such as recording are not possible. However, by providing a sensor (such as a gap for detecting submergence, a pair of electrodes, an open terminal, etc.) as described in Patent Document 1 for the apparatus disclosed in Patent Document 2, submersion is detected and a countermeasure for submergence is executed. It is possible.

Further, in Patent Documents 3 to 5, sensors (such as a pair of electrodes for detecting submergence and a float switch) that detect water and detect submergence are provided separately from the control box of the power window system. A technique for automatically opening the window by driving the motor in the window opening direction is disclosed.
Further, Patent Document 6 includes a water sensor (first detection means) for detecting water contact with the vehicle body separately from the control box of the power window system, and detects the contact state between the tire and the road surface. A second detection unit that detects that the water contact with the vehicle body is detected by the first detection unit and that the tire and the road surface are not in contact by the second detection unit; A submergence detection device that opens a window is disclosed. The second detection means detects the contact state between the tire and the road surface based on the suspension stroke, the tire air pressure, the value related to the expansion / contraction amount of the suspension shock absorber, the swing angle of the suspension link, or the coil load of the suspension. What to do is disclosed.

JP-A-11-36700 Japanese Patent Application Laid-Open No. 11-41961 JP 2000-204843 A Japanese Patent Laid-Open No. 10-292731 Japanese Patent Laid-Open No. 11-22301 JP 2000-25542 A

  However, among the conventional submergence detection techniques, in the configuration having a submergence detection means in the control box of the power window system as in Patent Document 1, after the vehicle has landed (for example, after falling into a river or the sea, Or after being involved in a flood), it was necessary for the water surface to reach the part where the control box was installed as water inundated into the car to some extent. For this reason, there has been a problem that submergence cannot always be detected sufficiently quickly. Although there is the idea that the power window will operate normally if it is not immersed in the control box, the battery will discharge rapidly due to leakage in other parts, and as a result, normal control will be performed in the control box. Even so, the actuator of the power window may fall into a state where it cannot function normally. Therefore, it is necessary to detect and respond to the abnormal situation of submergence as soon as possible, and the prior art disclosed in Patent Document 1 is not sufficient in this respect.

  Next, as described in Patent Documents 3 to 5, in the case of a configuration in which a sensor for detecting water is provided separately from the control box, the sensor is installed in the lower part of the vehicle body, thereby installing the control box. Submergence can be detected before the water surface reaches the position. However, the provision of a new sensor separately has the disadvantages of complicating the assembly, increasing the vehicle weight, and requiring a new installation space. In addition, there is a problem that the sensor may be erroneously determined to be submerged due to scattering of water during traveling during rain.

Further, as described in Patent Document 6, it has a separate water detection sensor (first detection means) and a second detection means for detecting the contact state between the tire and the road surface, and the first detection means is used for the vehicle body. When the contact of water is detected and the non-contact state between the tire and the road surface is detected by the second detection means, the configuration that determines that the vehicle is submerged has the following problems. In other words, since it is not determined to be submerged unless a non-contact state between the tire and the road surface is detected, it is not determined to be submerged when the tire is not completely lifted up, and submergence cannot be detected sufficiently early, or submergence cannot be detected reliably There is a problem of fear. For example, when a vehicle falls to a shallow depth such as a river, or when the water level from the road gradually increases due to flooding, it is detected that the tires are submerged without the tire rising from the road. Although there is a case that should be, there is a problem that the configuration of Patent Document 6 cannot be determined to be submerged in such a case. Moreover, since it is the structure which provides a separate sensor, there also exists a problem similar to the patent documents 3-5 mentioned above.
Therefore, the present invention has an object to provide a vehicle submergence detection device that can detect the submergence of a vehicle without providing a sensor for submergence detection, and more preferably, a vehicle submergence detection device that can detect submergence of a vehicle early and reliably. It is said.

The vehicle submergence detection device of the present application is a vehicle submergence detection device that detects submergence of a vehicle that performs wireless communication between a vehicle body and a tire,
Provided with a submergence determination means that monitors the communication state between the vehicle body and the tire and determines that the vehicle has submerged on the condition that the state in which communication is impossible continues for a set time or number of times. It is.

  Here, “submerged” means a situation in which a vehicle exists in a place where the water surface is above the road surface to such an extent that the tire does not contact the road surface (water bottom) with sufficient pressure. In contrast, a sufficiently shallow situation (a situation where the tire is in contact with the road surface with sufficient pressure) is excluded. This is because if the water depth is shallow and the tire is in contact with the road surface with a sufficient pressure, the vehicle can travel and no occupant accident will occur.

  In addition, “as a necessary condition that the state in which communication is not possible continues for a set time or number of times” means the following. That is, the condition for determining that the vehicle has been submerged includes at least the condition that the state in which communication between the vehicle body and the tire cannot be performed is continued for a set time or the number of times (hereinafter referred to as a basic condition). Means.

  That is, as an aspect of the present invention, an aspect in which it is determined that the vehicle has been submerged unconditionally if the basic condition is satisfied, and a vehicle is submerged only when another condition is satisfied in addition to the basic condition. This means that there may be a mode for determining that the operation has been performed.

  The “submergence determination unit” can be easily and inexpensively realized as a processing function of an existing control processing unit (for example, a control circuit in a controller such as TPMS or a control circuit of a power window system).

  In addition, “vehicles that perform wireless communication between a vehicle body and a tire” include, for example, a system called TPMS (a sensor that detects tire air pressure and communication means that wirelessly transmits detection data to the vehicle body side in the tire). There is a vehicle equipped with a system for monitoring tire pressure by receiving the detection data by a receiving means on the vehicle body side.

  Further, the “state incapable of communication” may be a state in which communication in one direction (for example, communication from the tire side to the vehicle body side) is impossible, or a state in which bidirectional communication is not possible (for example, from the vehicle body side). Even if transmission is performed on the tire side, a reply from the tire side cannot be normally received on the vehicle body side).

  According to the vehicle submergence detection device of the present application, the submergence of the vehicle can be detected quickly and reliably using the existing wireless communication means between the vehicle body and the tire without providing a sensor for submergence detection.

  This is because when the vehicle is submerged, the antenna of the wireless communication means (at least the antenna on the tire side) is submerged, and the radio wave is rapidly attenuated in water. It suddenly becomes impossible, and this state is maintained as long as it is submerged. On the other hand, the reason why wireless communication is disabled in situations other than submergence is a state in which communication becomes difficult (so-called null point) due to, for example, the relative positional relationship (tire rotation position) between the transmitter and the receiver, and is instantaneous. Wireless communication is only temporarily disabled. For this reason, if it is this apparatus which determines that the submergence of the vehicle has occurred when the communication disabled state continues for the set time or the number of times or more, the submergence of the vehicle can be detected early and reliably.

  The “tire” in the vehicle submersion detection device may be a part of a plurality of tires or all of the tires. That is, the submergence determining means in this case may be an aspect that determines that the vehicle is submerged when communication is impossible for some tires, or may be an embodiment that determines that it is submerged when communication is impossible for all tires. . Moreover, in a four-wheeled vehicle, it may be determined that the vehicle is submerged when communication is continuously impossible for adjacent tires or tires at diagonal positions. As described above, when the submergence is determined based on the communication states of a plurality of tires, there is a possibility that only one tire may be erroneously determined to be submerged when communication is disabled due to some factor (noise or the like). Can be resolved. Moreover, when based on the communication state of adjacent tires as described above, there is an advantage that submergence can be detected earlier even in a situation where only one side of the vehicle is submerged while preventing such erroneous determination. .

  Next, according to a preferred aspect of the present invention, the vehicle has a steering torque sensor, and the submergence determining means monitors measurement data of the steering torque sensor in addition to the communication state, and determines whether the necessary condition is satisfied and whether the steering torque is This is a mode in which it is determined that the vehicle has been submerged based on the decrease.

Here, the “vehicle having a steering torque sensor” includes, for example, an electric power steering system called EPS (a system that assists steering by outputting a steering assist force according to the output of the steering torque sensor from the electric actuator). There is a vehicle.
The “steering torque” is a torque required to operate the steering wheel (steering wheel) during steering (during steering) or a value corresponding to this torque (for example, the steering shaft during steering) This means the amount of distortion in the torsional direction that occurs or the value of the steering assist force output by the EPS electric actuator. The “steering torque sensor” is a sensor that detects “steering torque”.
Further, “based on the success / failure of the necessary condition and the decrease in the steering torque” means that the submergence is determined based on the AND condition of the success / failure of the necessary condition (whether or not the basic condition is satisfied) and the decrease in the steering torque. Means that. That is, when the necessary condition is satisfied (the above-described basic condition is satisfied), and when it is determined that the vehicle is submerged based on a decrease in the steering torque, it means that the submersion is determined to be submerged.

Further, “based on a decrease in steering torque” includes, for example, an aspect for determining that submergence has occurred when the steering torque decreases below a set threshold value, and the rate of change in the direction in which the steering torque decreases. There may be a mode in which it is determined that submersion has occurred when a set threshold value is exceeded.
In addition, in order to more reliably determine the state in which the steering torque is not reduced by the buoyancy due to submergence but the steering torque is not reduced by the steering assist force by the electric actuator, the following determination is performed, for example: It may be content. That is, when the actual steering force, which is the sum of the steering assist force and the steering torque, falls below a set threshold value, it is determined that submersion has occurred, or the actual steering force decreases in the decreasing direction. An aspect may be adopted in which it is determined that submergence has occurred when the rate of change exceeds a set threshold value.
Further, only the steering torque when the steering amount is a predetermined value or more may be used for the submergence determination.
It should be noted that the outside air temperature and the traveling speed may be taken into account in the submergence determination so that a decrease in steering torque due to a low μ road such as a frozen road surface is not erroneously determined as submergence. For example, the threshold value may be changed according to the outside air temperature or the traveling speed.
Further, the presence / absence of steering and the steering amount can be easily detected by an existing steering angle sensor.

In the above aspect, it is possible to detect the submergence of the vehicle more reliably by using an existing steering torque sensor without providing a submergence detection sensor.
This is because when the vehicle is submerged, the frictional resistance between the road surface and the tire is drastically reduced or zero due to buoyancy, and the steering torque is significantly reduced. For this reason, if it is this apparatus which determines submergence of a vehicle based on the success or failure of the said required condition and the fall of steering torque, it can detect submergence of a vehicle more reliably, without providing the sensor for submergence detection.

Next, another preferable aspect of the present invention is that the vehicle has a wheel speed sensor for the driving wheel and the driven wheel,
The submergence determination means monitors the measurement data of the wheel speed sensor in addition to the communication state, and determines that the vehicle has submerged based on the success or failure of the necessary condition and the relative decrease in the wheel speed of the driven wheel. To do.

Here, “a vehicle having wheel speed sensors for driving wheels and driven wheels” is, for example, a braking slip prevention system called ABS (when the wheel speed of each wheel is monitored to detect the start of wheel slip, There is a vehicle equipped with a system that forcibly adjusts the force to suppress slippage during braking. In recent years, ABS has become standard equipment in most passenger cars (four-wheeled vehicles).
Further, “based on the success / failure of the necessary condition and the relative decrease in the wheel speed of the driven wheel” means the relationship between the success / failure of the necessary condition (whether the above-mentioned basic condition is satisfied) and the wheel speed of the driven wheel. This means that the submergence is determined under the AND condition of the target drop. That is, when the necessary condition is satisfied (the above-mentioned basic condition is satisfied), and when it is determined that the vehicle is submerged based on the relative decrease in the wheel speed of the driven wheel, it means that the submergence is determined to be submerged. To do.
In addition, in “based on the relative decrease in the wheel speed of the driven wheel”, for example, the wheel speed of the driving wheel (or a part of the driving wheels or all of the driving wheels when there are a plurality of driving wheels) is set. When only the wheel speed of the driven wheel (or some driven wheels or all driven wheels if there are multiple driven wheels) falls below the set threshold value In addition, there may be a mode for determining that submersion has occurred, a mode for determining that submersion has occurred when the speed difference between the driving wheel and the driven wheel exceeds a set threshold value, and the like.
It should be noted that the brake operation state may be taken into consideration in the submergence determination so as not to erroneously determine that it is submerged when the wheel speed of the driven wheel is relatively decreased by the operation of the brake. For example, it may be added as an indispensable condition that it is determined that the brake is submerged.

If it is the said aspect, submergence of a vehicle can be detected more reliably using the existing wheel speed sensor, without providing the sensor for submergence detection.
This is because when the vehicle is submerged, the frictional resistance between the road surface and the tire is drastically reduced or zero, and the water resistance acts on the tire, so that the wheel speed of the driven wheel is significantly reduced. On the other hand, the drive wheels rotate as long as the engine is running and the mission is in the drive position. For this reason, if it is this apparatus which determines submergence of a vehicle based on the success or failure of the said required condition and the relative fall of the wheel speed of a driven wheel, submergence of a vehicle can be detected more reliably.

In another preferred aspect of the present invention, the vehicle has GPS and a dead reckoning function,
In addition to the communication state, the submergence determination means monitors the position information of the own vehicle obtained by the GPS and the position information of the own vehicle obtained by the dead reckoning function, and the success and failure of the necessary condition and both positions Based on the information mismatch, it is determined that the vehicle has been submerged.

Here, “GPS” is a known position measurement system used for a car navigation system or the like. In addition, the “dead reckoning function” means that a sensor (for example, a wheel speed sensor for each wheel) capable of determining a travel distance or a traveling direction is mounted on a vehicle and data measured by the sensor is continuously recorded or By summing up, it means a function of acquiring current position information with respect to position information at the time of departure (may include information on the direction of travel).
In addition, “based on the success / failure of the necessary condition and the mismatch between the two pieces of position information” means submerging the AND condition between the success / failure of the necessary condition (whether the above-mentioned basic condition is satisfied) and the mismatch between the two pieces of position information. It means to judge. That is, when the necessary condition is satisfied (the above-mentioned basic condition is satisfied) and the state where it is determined to be submerged based on the mismatch between the two pieces of position information, it means that the submergence is determined to be submerged.
In addition, “based on the mismatch between the two pieces of position information” includes, for example, a mode in which it is determined that submergence has occurred when a difference (distance) in absolute position of the vehicle obtained from each piece of position information exceeds a set threshold value. Submersion occurs when the difference in vehicle travel distance obtained from each position information (for example, the difference between the position measurement data at the time of sampling a predetermined number of times and the position measurement data at the time of sampling this time) exceeds a set threshold. A mode for determining that the vehicle has been submerged when the difference in the shape (for example, curvature) or the direction of travel (for example, the azimuth) of the travel path of the vehicle obtained from each position information exceeds a set threshold. And so on.

  It should be noted that when the vehicle is moving on a ferry, or when the vehicle is transported by truck, the position of the mission shift lever You may make it consider the operating state of a side brake. For example, it may be added as an indispensable condition that it is determined that the shift lever position is set to other than neutral or parking, or that the side brake is in an inoperative state.

In the above aspect, the submergence of the vehicle can be detected more reliably by using existing means (GPS and dead reckoning function) without providing a submergence detection sensor.
This is because when a vehicle is submerged, especially in flowing water such as a river, the vehicle moves irregularly along the water flow regardless of the driver's operation or wheel movement, and is measured by GPS. The position information changes to reflect this movement. However, in the submerged state, the change in the position information obtained by the dead reckoning function is completely unrelated to the actual change in the vehicle position, and the two pieces of position information are inconsistent with high probability. For example, in the case of a dead reckoning function for a four-wheeled vehicle that estimates position information based on the wheel speed of each wheel, the measurement result at the time of submergence is that there is no change in position information (the vehicle is in a stopped state), or the position information is the rotation of the drive wheel Accordingly, the state changes linearly (a straight vehicle traveling state at a speed corresponding to the rotational speed of the drive wheels). In the submerged state, the rotational speed (wheel speed) of the driven wheel becomes almost zero due to the resistance of water, and when the engine is stopped, the rotational speed of the driving wheel becomes almost zero, and when the engine is running, the driving wheel This is because both the left and right rotate in the same way. However, the movement of the vehicle due to the flow of water is not necessarily linear, and the movement distance is different from that measured by the dead reckoning function (for example, the movement distance based on the rotation amount of the wheel). Therefore, if the present apparatus determines that the vehicle has been submerged based on the success / failure of the necessary condition and the mismatch between the position information, the submergence of the vehicle can be detected with higher reliability.

  In addition, the function of each submergence determination in the various aspects mentioned above may combine two or more. For example, there can be a mode in which it is finally determined to be submerged if it is determined to be submerged by either one, or a mode in which it is finally determined to be submerged only when both determination results are submerged.

  According to the vehicle submergence detection device of the present invention, it is possible to detect the submergence of the vehicle using existing means without providing a sensor for submergence detection.

Hereinafter, after describing a comparative example, an embodiment of the present invention will be described based on the drawings.
(Comparative example)
First, a comparative example will be described. FIG. 1A is a diagram showing a vehicle K1 (four-wheeled vehicle equipped with a TPMS) including a vehicle submergence detection device (using a tire air pressure sensor) of a comparative example, and FIG. It is a figure which shows an example of a pneumatic pressure change.
As shown in FIG. 1A, the vehicle K1 includes a controller 1, a vehicle body side antenna 2, and a tire side sensor unit 3 as elements constituting the TPMS.

  Here, the controller 1 is a TPMS controller provided in a predetermined control box in the vehicle body, and includes a microcomputer and a radio signal communication circuit (at least a receiving circuit). For example, the controller 1 periodically receives a radio signal transmitted from the tire-side sensor unit 3 via the vehicle body-side antenna 2 and reads the air pressure data included in the radio signal so that the tire air pressure falls below, for example, an allowable value. When it falls, the control process as TPMS which performs the control which outputs a warning (alarm by a sound, light, a character display), and notifies a driver is performed.

Next, the vehicle body side antenna 2 is provided in the vicinity of each tire (for example, in the tire house of each tire), for receiving a radio signal from the tire side sensor unit 3 of each tire and inputting it to the controller 1. Is.
Next, the tire side sensor unit 3 is provided in each tire, a tire air pressure sensor that measures the air pressure of each tire, and a communication circuit (at least a transmission circuit) that transmits the air pressure data measured by the sensor as a radio signal. Provide an antenna.
A bidirectional TPMS that transmits and receives radio signals from the vehicle body side (antenna 2) to the tire side (sensor unit 3) may also be used. For example, the controller 1 transmits a request signal to the tire side sensor unit 3 periodically or at a set timing (for example, when the engine is started), and in response to the request signal, the tire side sensor unit There may be a mode in which 3 returns an answer signal including the latest air pressure data.

In addition to the basic control process as the TPMS described above, the controller 1 executes the process shown in the flowchart of FIG. Function as.
That is, the controller 1 executes the process of FIG. 2 periodically, for example. First, in step S1, the difference between the latest tire pressure data received from the tire side sensor unit 3 and the tire pressure data received before the previous time is calculated for each tire, and the tire pressure per unit time is calculated based on the calculation result. Obtain the amount of change (pressure change rate).
Next, in step S2, it is determined whether or not the pressure change rate obtained in step S1 is equal to or higher than a preset change rate, and if affirmative, the process proceeds to step S4, and if negative, the process proceeds to step S3. In order to minimize the possibility of misjudgment as a result of a decrease in tire air pressure due to wheel-off or jack-up during inspection or a temporary increase in tire air pressure when overstepping, the determination in step S2 is as follows. It is desirable that the determination condition is that the pressure change rate of all tires (or adjacent tires) is equal to or higher than the set change rate, and that the change in tire air pressure is in a decreasing direction. .

In step S3, it is determined whether or not the value of the pressure change flag set in step S6, which will be described later, is "True". If the result is affirmative, step S7 is determined. If the result is negative, one sequence of this routine is determined. End the process and return.
On the other hand, in step S4, the difference in the tire pressure change rate in which the determination in step S2 becomes affirmative as compared with the case in which the determination in step S2 becomes affirmative in the previous (or previous) sequence, It is determined whether or not it is within the set error range (that is, whether or not the rate of change in tire air pressure is the same as before the previous time). If the result is affirmative, the process proceeds to step S5. Proceed to step S6. In addition, in order to prevent erroneous determination due to instantaneous pressure fluctuation such as overcoming a step with higher reliability, when the determination of step S2 of the same tire is not positive in the sequence a predetermined number of times before (that is, When a predetermined pressure change is not repeatedly observed with the same tire a predetermined number of times), the process may return without executing steps S5 and S6 regardless of the determination result of step S4.
Then, in step S5, it is determined that a failure such as a tire puncture has occurred, and control such as outputting an alarm (sound, light, or character display alarm) informing the driver of the occurrence of the tire failure is performed.

On the other hand, in step S6, the value of the pressure change flag is set to “True”. However, when the determination in step S2 is not affirmative in the previous sequence, the value of the pressure change flag remains the initial value and is not set to “True”.
In step S7, it is determined that submergence has occurred, a submergence detection signal is output to another control circuit (for example, a control circuit of a power window system), and the other control circuit executes control of the submersion countermeasure. Or a submergence countermeasure is executed under the control of the controller 1 itself (TPMS control circuit).

In addition, as described in the background art section, the following measures can be taken as countermeasures against submersion in the power window system. That is, there may be one that automatically opens each window to the fully open position, or one that puts the control circuit in a special state so that at least the window can be opened even when submerged. Further, a measure for outputting an alarm notifying submergence may be executed, or a process for leaving a record (for example, diagnostic data) may be executed.
Further, in the process of FIG. 2, after steps S5 to S7, the process of one sequence is finished and the process returns. Further, the value of the pressure change flag may be returned to the initial value at a timing after step S7, for example.
Further, the state (submergence mode) in which it is determined that the submergence has occurred and the countermeasure for submergence is being performed may be canceled after elapse of a predetermined time, for example.

  According to the processing described above, if a change in tire air pressure (preferably a change in a decreasing direction) exceeding the set change rate is temporarily observed, the pressure change flag is set to “True” in steps S4 and S6. After the setting, since the process proceeds from step S3 to step S7, it is determined that the vehicle has been submerged. If the change in tire air pressure continues, the process proceeds from step S4 to step S5, where it is determined as puncture or the like, and puncture or the like is identified and submerged.

For this reason, according to the vehicle submergence detection device of the present embodiment, the submergence of the vehicle can be detected early and reliably using an existing tire air pressure sensor without providing a sensor for submergence detection.
This is because, when the submergence occurs, the vehicle weight is not applied to the tire more than usual due to the buoyancy of water, so that the tire air pressure is temporarily reduced, for example, as shown in FIG. For this reason, if it is this apparatus, if the change rate etc. used as the reference | standard of determination in said step S2 are set to an appropriate value by experiment etc. previously, a submerged state can be detected.
Further, if the air pressure is reduced due to puncture or the like, for example, as shown in FIG. However, if the air pressure decreases due to submergence, the air pressure decreases rapidly and then the decreased air pressure is maintained, or in the process where the vehicle gradually sinks due to water immersion, the air pressure once decreased due to external water pressure Conversely, it rises gradually. Therefore, if the present apparatus determines that it is submerged due to a temporary change in tire air pressure, it is possible to reliably detect submersion as distinguished from a change in tire air pressure due to puncture or the like. In addition, since this device does not necessarily have a problem with the contact state between the tire and the road surface, even if the tire does not leave the road surface, it is configured to determine that it is submerged if the tire air pressure changes by a predetermined change rate or more. And it can be detected with high reliability.

(First embodiment)
Next, a first embodiment of the present invention will be described. This example is a vehicle submergence detection device that uses wireless communication means between a vehicle body and a tire in the vehicle K1 (four-wheeled vehicle equipped with TPMS) shown in FIG. 1A, and the system configuration is a comparative example ( It may be the same as in FIG. However, bidirectional communication is possible between the controller 1 and the tire side sensor unit 3.

In this case, the controller 1 functions as a submergence determination unit of the vehicle submergence detection device by executing the process shown in the flowchart of FIG. 3 in addition to the basic control process as the TPMS.
That is, the controller 1 executes the process of FIG. 3 periodically, for example. First, in step S11, the value of the communication error counter is set to zero. Next, in step S12, it is determined whether or not the processing of steps S15 to S18 has been completed for all tires. If affirmative, the process proceeds to step S19, and if negative, the process proceeds to step S15.

  In step S15, a request signal is transmitted to the tire side sensor unit 3 to request measurement and return of the tire pressure. Next, in step S16, it is determined whether or not an answer signal from the tire side sensor unit 3 has been received. If the answer is affirmative, the process proceeds to step S17, and if not, the process proceeds to step S18. In step S17, normal processing is executed. The normal process is a basic control process as the above-described TPMS. For example, the tire pressure data included in the received answer signal is read, and if this is below the allowable value, an alarm is output as a tire pressure abnormality. Etc. are executed. In step S18, the value of the communication error counter is counted up.

On the other hand, in step S19, it is determined whether or not the value of the communication error counter matches the number of tires (in this case, 4). If the result is affirmative, the process proceeds to step S20, and if negative, the process proceeds to step S21. Then, in step S20, after counting up the submergence flag, the processing of one sequence is terminated and the process returns. In step S21, the value of the submergence flag is set to zero, and then the process returns.
Although not shown in the figure, in this case, the controller 1 reads the value of the submergence flag after step S20 or S21, determines whether this value is equal to or greater than the set value, and if it is equal to or greater than the set value. Execute processing to determine that it is submerged.

  According to the processing described above, TPMS wireless communication is executed for all tires, and for tires for which the answer signal has been normally received, normal processing is executed for tires that have not received the answer signal (there is a communication error). For the tire, the value of the communication error counter is counted up accordingly (steps S12, S15 to S18). When the value of the communication error counter is equal to the value of four tires (that is, when there is a communication error for all tires), step S20 is executed through step S19, and the value of the submergence flag is counted up. Is done. Then, when the incommunicable state continues for a set number of times for all tires in this way, it is determined that the submergence has occurred because the value of the submergence flag is greater than or equal to the set value.

For this reason, according to the vehicle submergence detection device of the present embodiment, the submergence of the vehicle can be detected quickly and reliably using the existing wireless communication means between the vehicle body and the tire without providing a sensor for submergence detection. .
This is because when the vehicle is submerged, the antenna of the TPMS (at least the antenna of the tire side sensor unit 3) is also submerged, and the radio wave is rapidly attenuated in water. It suddenly becomes impossible, and this state is maintained as long as it is submerged. On the other hand, the wireless communication is not possible in situations other than submergence, for example, when communication is difficult due to the relative positional relationship (tire rotation position) of the vehicle body antenna 2 and the tire sensor unit 3 (so-called null point). That is why wireless communication is temporarily disabled. For this reason, if the present apparatus determines that the vehicle has been submerged when the incommunicable state continues for the set number of times or more, the submergence of the vehicle can be detected early and reliably.

(Second embodiment)
Next, a second embodiment will be described. This example is a vehicle submergence detection device that detects submergence of a vehicle having an EPS including a steering torque sensor, and FIG. 4 is a diagram illustrating the EPS (electric power steering system).
In FIG. 4, reference numeral 11 denotes a handle (steering wheel), reference numeral 11a denotes a steering shaft, reference numeral 12 denotes a pinion gear connected to the handle via the steering shaft 11a, reference numeral 13 denotes a rack shaft corresponding to the pinion gear 12, reference numeral 14 Is a tire (wheel). As elements constituting the EPS, a steering torque sensor 15 that detects a steering torque applied to the handle 11, a motor 16 that generates a steering assist force, and an auxiliary drive mechanism 17 that transmits the steering assist force to the rack shaft 13; A controller (control device) 18 is provided for controlling the energization amount (output of the motor 16) to the motor 16 in accordance with the detected steering torque. The controller 18 receives a vehicle speed signal from the vehicle speed sensor 19 and is supplied with power from the battery 20.

In this case, the controller 18 functions as a submergence determination unit of the vehicle submergence detection device by executing the following process in addition to the basic control process as the EPS.
That is, the measurement data of the steering torque sensor 15 is monitored, and it is determined that the vehicle has been submerged based on the decrease in the steering torque. Specifically, for example, an aspect that determines that submergence has occurred when the steering torque drops below a set threshold value, or the rate of change in the steering torque reduction direction exceeds a set threshold value. There may be a mode in which it is sometimes determined that submergence has occurred. It should be noted that the outside air temperature and the traveling speed may be considered in the submergence determination so that a decrease in steering torque due to a low μ road such as a frozen road surface is not erroneously determined as submergence. For example, the threshold value may be changed according to the outside air temperature or the traveling speed (vehicle speed signal from the vehicle speed sensor 19).

According to the vehicle submergence detection device of this embodiment, it is possible to detect the submergence of the vehicle using an existing steering torque sensor without providing a sensor for submergence detection.
This is because when the vehicle is submerged, the frictional resistance between the road surface and the tire is drastically reduced or zero, and the steering torque is significantly reduced. For this reason, if it is this apparatus which determines submergence of a vehicle based on the fall of steering torque, submergence of a vehicle can be detected.

(Third embodiment)
Next, a third embodiment will be described. The present embodiment is a vehicle submergence detection device that detects submergence of a vehicle having an ABS. For example, measurement data of an ABS wheel speed sensor (not shown) is monitored by an ABS controller (not shown). It is determined that the vehicle has been submerged based on the relative decrease in the wheel speed of the driving wheel.

Specifically, in the state where the wheel speed of the drive wheel (or a part of the drive wheels or all the drive wheels when there are a plurality of drive wheels) exceeds a set threshold value, the driven wheel (driven wheel) When there are a plurality of wheel drives, some of the driven wheels or all the driven wheels) determine that submergence has occurred when only the wheel speed falls below a set threshold, and the drive wheels and driven wheels. There may be a mode in which it is determined that submergence has occurred when the speed difference exceeds a set threshold value.
It should be noted that the brake operation state may be taken into consideration in the submergence determination so as not to erroneously determine that it is submerged when the wheel speed of the driven wheel is relatively decreased by the operation of the brake. For example, it may be added as an indispensable condition that it is determined that the brake is submerged.

According to the vehicle submergence detection device of the present embodiment, the submergence of the vehicle can be detected early and reliably using an existing wheel speed sensor without providing a sensor for submergence detection.
This is because when the vehicle is submerged, the frictional resistance between the road surface and the tire is drastically reduced or zero, and the water resistance acts on the tire, so that the wheel speed of the driven wheel is significantly reduced. On the other hand, the drive wheels rotate as long as the engine is running and the mission is in the drive position. That is, in the normal state where no submergence occurs, for example, as shown in FIG. 5A, all signals indicating the rotation state of each tire (tires 1 to 4) repeat high and low at substantially the same cycle. However, when submerged in the running state, the rotation of the driven wheel will stop soon, so the signal indicating the rotation of the driven wheel (tires 1 and 2) does not change as shown in FIG. 5B, for example. Since the drive wheels (tires 3 to 4) are continuously rotated, a signal indicating the rotation is continued. For this reason, if it is this apparatus which determines submergence of a vehicle based on the relative fall of the wheel speed of a driven wheel, submergence of a vehicle can be detected.

  In the case of this embodiment, there is a concern about erroneous determination due to wheel removal. However, when one of the drive wheels of a four-wheeled vehicle is removed, the other drive wheel is grounded and stopped, so that all the drive wheels are rotating is a necessary condition for submergence determination. In this case, it is possible to prevent erroneous determination as being submerged due to this wheel removal. In addition, when all of the driving wheels are derailed (for example, when a front wheel drive type four-wheeled vehicle falls from the quay and the two front wheels derail), it is determined that the vehicle is submerged and measures against submersion ( Even if the window is automatically opened, etc., it is a state that requires ease of escape as in the case of actual submergence.

(Fourth embodiment)
Next, a fourth embodiment will be described. The present embodiment is a vehicle submergence detection device that detects submergence of a vehicle having GPS and a dead reckoning function. For example, the GPS controller obtains the position information of the host vehicle obtained by GPS and the self-subject obtained by the dead reckoning function. The position information of the vehicle is monitored, and it is determined that the vehicle has been submerged based on the mismatch between the position information.

  Specifically, a mode for determining that submergence has occurred when the difference (distance) of the absolute position of the vehicle obtained from each position information exceeds a set threshold value, and the moving distance of the vehicle obtained from each position information ( For example, a mode of determining that submersion has occurred when the difference between the position measurement data at the time of sampling a predetermined number of times and the position measurement data at the time of sampling this time exceeds a set threshold, and the vehicle obtained from each position information There may be a mode in which it is determined that submergence has occurred when a difference in the shape (for example, curvature) of the traveling path or the traveling direction (for example, azimuth) exceeds a set threshold value.

  It should be noted that when the vehicle is moving on a ferry, or when the vehicle is transported by truck, the position of the mission shift lever You may make it consider the operating state of a side brake. For example, it may be added as an indispensable condition that it is determined that the shift lever position is set to a position other than neutral or parking, or that the side brake brake is inactive.

According to the vehicle submergence detection device of this embodiment, the submergence of the vehicle can be detected by using existing means (GPS and dead reckoning function) without providing a sensor for submergence detection.
This is because when a vehicle is submerged, especially in flowing water such as a river, the vehicle moves irregularly along the water flow regardless of the driver's operation or wheel movement, and is measured by GPS. The position information changes to reflect this movement. However, in the submerged state, the change in the position information obtained by the dead reckoning function is completely unrelated to the actual change in the vehicle position, and the two pieces of position information are inconsistent with high probability. For example, in the case of a dead reckoning function for a four-wheeled vehicle that estimates position information based on the wheel speed of each wheel, the measurement result at the time of submergence is that there is no change in position information (the vehicle is in a stopped state), or the position information is the rotation of the drive wheel Accordingly, the state changes linearly (a straight vehicle traveling state at a speed corresponding to the rotational speed of the drive wheels). In the submerged state, the rotational speed (wheel speed) of the driven wheel becomes almost zero due to the resistance of water, and when the engine is stopped, the rotational speed of the driving wheel becomes almost zero, and when the engine is running, the driving wheel This is because both the left and right rotate in the same way. However, the movement of the vehicle due to the flow of water is not necessarily linear, and the movement distance is different from that measured by the dead reckoning function (for example, the movement distance based on the rotation amount of the wheel). Therefore, if the present apparatus determines that the vehicle has been submerged based on the mismatch between the position information, the submergence of the vehicle can be detected.

The present invention is not limited to the above-described embodiments, and various modifications and applications are possible.
For example, the submergence determination means may be configured as a processing function of another controller (for example, a controller of a power window system).
Moreover, the structure which performs combining any two or more of the submergence determination of each form mentioned above, and performs the final determination of submergence based on these several determination results may be sufficient.

It is a figure explaining a vehicle submergence detection apparatus (comparative example). It is a flowchart which shows the process of submergence determination (comparative example). It is a flowchart which shows the process of submergence determination (1st form example). It is a figure which shows EPS. It is a figure explaining the rotation state of the wheel at the time of submergence.

Explanation of symbols

1, 18 Controller (submergence judging means)
K1 vehicle

Claims (4)

A vehicle submergence detection device that detects submergence of a vehicle that performs wireless communication between a vehicle body and a tire,
Provided with a submergence determination means for monitoring the communication state between the vehicle body and the tire, and determining that the vehicle has been submerged on the condition that the state in which communication is impossible continues for a set time or number of times. A vehicle submergence detection device. The vehicle has a steering torque sensor,
The submergence determining means monitors the measurement data of the steering torque sensor in addition to the communication state, and determines that the submergence of the vehicle has occurred based on success or failure of the necessary condition and a decrease in steering torque. The vehicle submergence detection device according to claim 1. The vehicle has wheel speed sensors for driving wheels and driven wheels,
The submergence determination means monitors the measurement data of the wheel speed sensor in addition to the communication state, and determines that the submergence of the vehicle has occurred based on the success or failure of the necessary condition and the relative decrease in the wheel speed of the driven wheel. The vehicle submergence detection device according to claim 1. The vehicle has GPS and dead reckoning function,
The submergence determining means monitors, in addition to the communication state, the position information of the own vehicle obtained by the GPS and the position information of the own vehicle obtained by the dead reckoning function, and the success or failure of the necessary condition and both positions The vehicle submersion detection device according to claim 1, wherein it is determined that the submergence of the vehicle has occurred based on the information mismatch.

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