JPH05133831A - Tire air pressure detection device - Google Patents
Tire air pressure detection deviceInfo
- Publication number
- JPH05133831A JPH05133831A JP3294622A JP29462291A JPH05133831A JP H05133831 A JPH05133831 A JP H05133831A JP 3294622 A JP3294622 A JP 3294622A JP 29462291 A JP29462291 A JP 29462291A JP H05133831 A JPH05133831 A JP H05133831A
- Authority
- JP
- Japan
- Prior art keywords
- tire
- air pressure
- resonance frequency
- tire air
- vehicle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 26
- 230000007423 decrease Effects 0.000 claims description 9
- 239000000284 extract Substances 0.000 claims 1
- 238000000605 extraction Methods 0.000 claims 1
- 238000000034 method Methods 0.000 description 16
- 238000010586 diagram Methods 0.000 description 15
- 230000001133 acceleration Effects 0.000 description 13
- 238000012935 Averaging Methods 0.000 description 7
- 239000006096 absorbing agent Substances 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000010426 asphalt Substances 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
Landscapes
- Measuring Fluid Pressure (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、車両のタイヤの空気圧
の状態を検知するタイヤ空気圧検知装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire air pressure detecting device for detecting a tire air pressure condition of a vehicle.
【０００２】[0002]
【従来の技術】従来、タイヤの空気圧を検知する装置と
しては、タイヤの内部にタイヤ空気圧に応動する圧力応
動部材等を設け、直接的にタイヤの空気圧を検知するも
のが提案されている。しかし、直接的にタイヤの空気圧
を検知する装置では、タイヤの内部に圧力応動部材等を
設ける必要があることから構造が複雑となり、また価格
も高価となってしまうという問題があった。2. Description of the Related Art Conventionally, as a device for detecting a tire air pressure, there has been proposed a device in which a pressure responsive member which responds to a tire air pressure is provided inside a tire to directly detect the tire air pressure. However, in a device for directly detecting the tire air pressure, there is a problem that the structure becomes complicated and the price becomes expensive because it is necessary to provide a pressure responsive member or the like inside the tire.
【０００３】このため、タイヤの空気圧が低下したとき
にタイヤ半径が変化する（短くなる）ことを利用して、
各車輪の車輪速度を検出する車輪速度センサの検出信号
に基づいて、車両のタイヤの空気圧を間接的に検知する
ことが提案されている。Therefore, the fact that the tire radius changes (becomes shorter) when the tire air pressure decreases,
It has been proposed to indirectly detect the tire air pressure of a vehicle based on a detection signal of a wheel speed sensor that detects the wheel speed of each wheel.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、検出対
象であるタイヤ半径は、磨耗等による個体差があった
り、旋回，制動，発進等の走行状態の影響を受けやす
い。さらに、近年普及が著しいラジアルタイヤは、タイ
ヤ空気圧の変化によるタイヤ半径の変形量が小さい（例
えば、タイヤの空気圧が１ｋｇ／ｃｍ2低下したとき、
タイヤ半径の変形量は約１ｍｍである。）。このような
理由から、タイヤ半径の変形量からタイヤ空気圧の変化
を間接的に検知する方式は、検知精度が充分に確保でき
ないという問題がある。However, the tire radius to be detected is subject to individual differences due to wear and the like, and is easily influenced by running conditions such as turning, braking and starting. Further, radial tires, which have been widely used in recent years, have a small amount of deformation of the tire radius due to a change in tire air pressure (for example, when the tire air pressure decreases by 1 kg / cm 2 ,
The amount of deformation of the tire radius is about 1 mm. ). For this reason, the method of indirectly detecting the change in the tire air pressure from the deformation amount of the tire radius has a problem that the detection accuracy cannot be sufficiently secured.
【０００５】本発明は上記の点に鑑みてなされたもので
あり、間接的にタイヤ空気圧を検知するとともに、その
検知精度を向上することができるタイヤ空気圧検知装置
を提供することを目的とするものである。The present invention has been made in view of the above points, and an object of the present invention is to provide a tire air pressure detecting device capable of indirectly detecting a tire air pressure and improving the detection accuracy. Is.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明によるタイヤ空気圧検知装置は、車両の走行
時に、タイヤの振動周波数成分を含む信号を出力する出
力手段と、前記タイヤの振動周波数成分を含む信号から
共振周波数を抽出する抽出手段と、前記共振周波数に基
づいて、前記タイヤの空気圧の状態を検知する検知手段
とを備えることを特徴とする。In order to achieve the above object, a tire air pressure detecting device according to the present invention comprises an output means for outputting a signal including a vibration frequency component of a tire when the vehicle is running, and a vibration of the tire. It is characterized in that it is provided with an extracting means for extracting a resonance frequency from a signal including a frequency component, and a detecting means for detecting a state of air pressure of the tire based on the resonance frequency.
【０００７】[0007]
【作用】上記構成により、タイヤの振動周波数成分を含
む信号から共振周波数を抽出し、この抽出された共振周
波数に基づいて、タイヤの空気圧の状態が検知される。With the above structure, the resonance frequency is extracted from the signal including the vibration frequency component of the tire, and the tire air pressure state is detected based on the extracted resonance frequency.
【０００８】ここで、タイヤの空気圧が変化すると、そ
れによってタイヤのばね定数も変化する。このタイヤの
ばね定数の変化により、タイヤの振動周波数成分におけ
る共振周波数が変化するので、抽出した共振周波数に基
づき、タイヤの空気圧の状態を検知することができる。When the tire air pressure changes, the spring constant of the tire also changes accordingly. Since the resonance frequency in the vibration frequency component of the tire changes due to the change of the spring constant of the tire, it is possible to detect the tire air pressure state based on the extracted resonance frequency.
【０００９】[0009]
【実施例】以下、本発明の第１実施例を図面に基づいて
詳しく説明する。図１は、第１実施例の全体の構成を示
す構成図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing the overall configuration of the first embodiment.
【００１０】図１に示すように、車両の各タイヤ１ａ〜
１ｄに対応して車輪速度センサが設けられている。各車
輪速度センサは、歯車２ａ〜２ｄ及びピックアップコイ
ル３ａ〜３ｄによって構成されている。歯車２ａ〜２ｄ
は、各タイヤ１ａ〜１ｄの回転軸（図示せず）に同軸的
に取り付けられており、円盤状の磁性体より成る。ピッ
クアップコイル３ａ〜３ｄは、これらの歯車２ａ〜２ｄ
の近傍に所定の間隔を置いて取り付けられ、歯車２ａ〜
２ｄ、すなわちタイヤ１ａ〜１ｄの回転速度に応じた周
期を有する交流信号を出力する。ピックアップコイル３
ａ〜３ｄから出力される交流信号は、波形整形回路，Ｒ
ＯＭ，ＲＡＭ等よりなる公知の電子制御装置（ＥＣＵ）
４に入力され、波形整形を含む所定の信号処理が行われ
る。この信号処理の結果は表示部５に入力され、表示部
５は運転者に対して各タイヤ１ａ〜１ｄの空気圧の状態
を報知する。この表示部５は、各タイヤ１ａ〜１ｄの空
気圧の状態を独立に表示しても良いし、一つの警告ラン
プを設けて、いずれか一つのタイヤの空気圧が基準空気
圧よりも低下したときに点灯させて、それを警告するよ
うにしても良い。As shown in FIG. 1, each tire 1a of the vehicle is
A wheel speed sensor is provided corresponding to 1d. Each wheel speed sensor includes gears 2a to 2d and pickup coils 3a to 3d. Gears 2a-2d
Is coaxially attached to the rotating shafts (not shown) of the tires 1a to 1d and is made of a disk-shaped magnetic body. The pickup coils 3a to 3d have these gears 2a to 2d.
Mounted at a predetermined interval in the vicinity of the gears 2a to
2d, that is, an AC signal having a cycle corresponding to the rotation speeds of the tires 1a to 1d is output. Pickup coil 3
The AC signals output from a to 3d are waveform shaping circuits, R
Known electronic control unit (ECU) including OM, RAM, etc.
4, and predetermined signal processing including waveform shaping is performed. The result of this signal processing is input to the display unit 5, and the display unit 5 notifies the driver of the air pressure state of each of the tires 1a to 1d. The display unit 5 may independently display the air pressure states of the tires 1a to 1d, or may be provided with one warning lamp and light up when the air pressure of any one of the tires is lower than the reference air pressure. You may make it warn about it.
【００１１】ここで、まず本実施例におけるタイヤ空気
圧の検知原理について説明する。車両が、例えば舗装さ
れたアスファルト路面を走行した場合、その路面表面の
微小な凹凸により上下及び前後方向の力を受け、その力
によってタイヤは上下及び前後方向に振動する。このタ
イヤ振動時の車両ばね下の加速度の周波数特性は図２に
示すようなものとなる。図２に示すように、加速度の周
波数特性は２点においてピーク値を示し、ａ点は車両の
ばね下における上下方向の共振周波数であり、ｂ点は車
両のばね下における前後方向の共振周波数である。First, the principle of tire pressure detection in this embodiment will be described. When a vehicle travels on a paved asphalt road surface, for example, fine irregularities on the surface of the road surface receive vertical and longitudinal forces, which cause the tire to vibrate vertically and longitudinally. The frequency characteristic of the acceleration under the vehicle spring when the tire vibrates is as shown in FIG. As shown in FIG. 2, the frequency characteristic of acceleration shows a peak value at two points, point a is the resonance frequency in the vertical direction under the unsprung part of the vehicle, and point b is the resonance frequency in the longitudinal direction under the unsprung part of the vehicle. is there.
【００１２】一方、タイヤの空気圧が変化すると、タイ
ヤゴム部のばね定数も変化するため、上記の上下方向及
び前後方向の共振周波数がともに変化する。例えば、図
３に示すように、タイヤの空気圧が低下した場合には、
タイヤゴム部のばね定数も低下するので、上下方向及び
前後方向の共振周波数がともに低下する。従って、タイ
ヤの振動周波数より、車両のばね下における上下方向及
び前後方向の共振周波数の少なくとも一方を抽出すれ
ば、この共振周波数に基づいてタイヤの空気圧の状態を
検知することができる。On the other hand, when the air pressure of the tire changes, the spring constant of the rubber portion of the tire also changes, so that the resonance frequencies in the vertical direction and the front-back direction both change. For example, as shown in FIG. 3, when the tire air pressure decreases,
Since the spring constant of the tire rubber portion is also reduced, both the vertical and longitudinal resonance frequencies are reduced. Therefore, by extracting at least one of the resonance frequency in the up-down direction and the front-rear direction under the spring of the vehicle from the vibration frequency of the tire, it is possible to detect the tire air pressure state based on the resonance frequency.
【００１３】そのため、本実施例では、車輪速度センサ
の検出信号から、車両のばね下における上下方向及び前
後方向の共振周波数を抽出する。これは、発明者らの詳
細な検討の結果、車輪速度センサの検出信号には、タイ
ヤの振動周波数成分が含まれていることが判明したため
である。すなわち、車輪速度センサの検出信号を周波数
解析した結果、図４に示すように２点でピーク値を示す
とともに、タイヤの空気圧が低下すると、その２点のピ
ーク値も低下することが明らかとなった。Therefore, in this embodiment, the resonance frequencies in the up-down direction and the front-rear direction of the unsprung part of the vehicle are extracted from the detection signal of the wheel speed sensor. This is because, as a result of detailed study by the inventors, it was found that the detection signal of the wheel speed sensor includes a vibration frequency component of the tire. That is, as a result of frequency analysis of the detection signal of the wheel speed sensor, it becomes clear that the peak value is shown at two points as shown in FIG. 4 and that when the tire air pressure is lowered, the peak values at those two points are also lowered. It was
【００１４】これにより、本実施例によれば、近年搭載
車両の増加しているアンチスキッド制御装置（ＡＢＳ）
を備える車両等は、既に各タイヤに車輪速度センサが装
備されているため、何ら新たなセンサ類を追加しなくと
もタイヤ空気圧の検知が可能となる。また、車両の実用
範囲では、上記共振周波数の変化量はほとんどタイヤ空
気圧の変化に起因するタイヤばね定数の変化に基づくも
のであるため、例えばタイヤの磨耗等の他の要因の影響
を受けることなく安定した空気圧検知が可能となる。As a result, according to the present embodiment, the anti-skid control device (ABS), which has been increasing in the number of vehicles equipped in recent years
A vehicle or the like equipped with is equipped with a wheel speed sensor in each tire, so that tire pressure can be detected without adding any new sensor. Further, in the practical range of the vehicle, the amount of change in the resonance frequency is almost based on the change in the tire spring constant caused by the change in tire air pressure, so that it is not affected by other factors such as tire wear. Stable air pressure detection is possible.
【００１５】図１０に、ＥＣＵ４が実行する処理内容を
表したフローチャートを示す。なお、ＥＣＵ４は各車輪
１ａ〜１ｄに対して同様の処理を行うため、図１０のフ
ローチャートは１車輪に対しての処理の流れのみを示し
ている。また、これ以後の説明において、各符号の添字
は省略する。さらに、図１０に示すフローチャートで
は、特にタイヤの空気圧が基準値以下に低下したことを
検知し、運転者に対して警告を行う例について示してい
る。FIG. 10 shows a flowchart showing the contents of processing executed by the ECU 4. Since the ECU 4 performs the same processing for each wheel 1a to 1d, the flowchart of FIG. 10 shows only the processing flow for one wheel. Further, in the following description, the subscripts of the respective reference numerals are omitted. Further, the flowchart shown in FIG. 10 shows an example in which it is detected that the tire air pressure has dropped below a reference value and a warning is given to the driver.
【００１６】図１０において、ステップ１００では、ピ
ックアップコイル３から出力された交流信号（図５）を
波形整形してパルス信号とした後に、そのパルス間隔を
その間の時間で除算することにより車輪速度ｖを演算す
る。この車輪速度ｖは、図６に示すように、通常、タイ
ヤの振動周波数成分を含む多くの高周波成分を含んでい
る。ステップ１１０では、演算された車輪速度ｖの変動
幅Δｖが基準値ｖ0 を超えたか否かを判定する。このと
き、車輪速度ｖの変動幅Δｖが基準値ｖ0 を超えている
と判定されると、ステップ１２０に進む。ステップ１２
０では、車輪速度ｖの変動幅Δｖが基準値ｖ0 を超えて
いる時間ΔＴが、所定時間ｔ0 を超えたか否かを判定す
る。上記ステップ１１０，１２０での処理は、車両が走
行している路面が、本実施例の検知手法によってタイヤ
空気圧の検知が可能な路面か否かを判定するために行う
ものである。つまり、本実施例では、タイヤの空気圧の
検知を、タイヤの振動周波数成分に含まれる共振周波数
の変化に基づいて行う。このため、車輪速度ｖがある程
度変動し、かつそれが継続されなければ、上記共振周波
数を算出するための充分なデータを得ることができな
い。なお、ステップ１２０における判定では、車輪速度
ｖの変動幅Δｖが基準値ｖ0 を超えた時点で所定時間Δ
ｔが設定され、この所定時間Δｔ内に再び車輪速度ｖの
変動幅Δｖが基準値ｖ0を超えると、時間ΔＴの計測が
継続される。In FIG. 10, in step 100, after the waveform of the AC signal (FIG. 5) output from the pickup coil 3 is shaped into a pulse signal, the pulse interval is divided by the time interval between the wheel speeds v. Is calculated. As shown in FIG. 6, the wheel speed v usually includes many high frequency components including the vibration frequency component of the tire. In step 110, it is determined whether or not the calculated fluctuation width Δv of the wheel speed v exceeds the reference value v 0 . At this time, if it is determined that the variation width Δv of the wheel speed v exceeds the reference value v 0 , the process proceeds to step 120. Step 12
At 0, it is determined whether or not the time period ΔT in which the fluctuation width Δv of the wheel speed v exceeds the reference value v 0 exceeds the predetermined time t 0 . The processing in steps 110 and 120 is performed to determine whether or not the road surface on which the vehicle is traveling is a road surface on which the tire air pressure can be detected by the detection method of this embodiment. That is, in the present embodiment, the tire air pressure is detected based on the change in the resonance frequency included in the tire vibration frequency component. Therefore, if the wheel speed v fluctuates to some extent and is not continued, sufficient data for calculating the resonance frequency cannot be obtained. In the determination in step 120, when the fluctuation width Δv of the wheel speed v exceeds the reference value v 0 , the predetermined time Δ
When t is set and the fluctuation width Δv of the wheel speed v again exceeds the reference value v 0 within this predetermined time Δt, the measurement of the time ΔT is continued.
【００１７】ステップ１１０及びステップ１２０におい
て、ともに肯定判断されるとステップ１３０に進み、ど
ちらか一方において否定判断されると、ステップ１００
に戻る。ステップ１３０では、演算された車輪速度に対
して周波数解析（ＦＦＴ）演算を行うとともに、その演
算回数Ｎをカウントする。このＦＦＴ演算を行った結果
の一例を図７に示す。If both steps 110 and 120 are affirmatively determined, the process proceeds to step 130, and if either one is negatively determined, the step 100 is performed.
Return to. In step 130, frequency analysis (FFT) calculation is performed on the calculated wheel speed, and the number of times N of calculation is counted. FIG. 7 shows an example of the result of this FFT calculation.
【００１８】図７に示すように、実際に車両が一般道を
走行して得られる車輪速度に対してＦＦＴ演算を実施す
ると、非常にランダムな周波数特性となることが通常で
ある。これは、路面に存在する微小な凹凸の形状（大き
さや高さ）が全く不規則なためであり、従って車輪速度
データ毎にその周波数特性は変動することとなる。従っ
て、本実施例では、この周波数特性の変動をできるだけ
低減するために、複数回のＦＦＴ演算結果の平均値を求
める。このため、ステップ１４０では、ステップ１３０
におけるＦＦＴ演算回数Ｎが所定回数ｎ0 に達したか否
かを判定する。そして、演算回数Ｎが所定回数ｎ0 に達
っしていないときには、さらにステップ１００からステ
ップ１３０の処理を繰り返し実行する。一方、演算回数
Ｎが所定回数ｎ0 に達っしているときには、ステップ１
５０に進んで平均化処理を行う。この平均化処理は、図
８に示すように、各ＦＦＴ演算結果の平均値を求めるも
のであり、各周波数成分のゲインの平均値が算出され
る。このような平均化処理によって、路面によるＦＦＴ
演算結果の変動を低減することが可能となる。As shown in FIG. 7, when the FFT calculation is performed on the wheel speed obtained by actually traveling the vehicle on a general road, it is usual that the frequency characteristic becomes extremely random. This is because the shape (size and height) of the minute irregularities present on the road surface is completely irregular, and therefore the frequency characteristic varies for each wheel speed data. Therefore, in this embodiment, in order to reduce the variation of the frequency characteristic as much as possible, the average value of the FFT calculation results of a plurality of times is obtained. Therefore, in step 140, step 130
It is determined whether or not the number of FFT operations N has reached a predetermined number n 0 . Then, when the number of calculations N has not reached the predetermined number n 0 , the processes from step 100 to step 130 are repeated. On the other hand, when the number of calculations N has reached the predetermined number n 0 , step 1
Proceeding to 50, averaging processing is performed. In this averaging process, as shown in FIG. 8, the average value of each FFT calculation result is obtained, and the average value of the gain of each frequency component is calculated. By such an averaging process, the FFT depending on the road surface
It is possible to reduce the fluctuation of the calculation result.
【００１９】しかし、上述の平均化処理だけでは、ノイ
ズ等によって車両のばね下の上下方向及び前後方向の共
振周波数のゲインが、その近辺の周波数のゲインに比較
して必ずしも最大ピーク値になるとは限らないという問
題がある。そこで、本実施例では、上述の平均化処理に
引き続き、ステップ１６０において以下の移動平均処理
を実施する。However, with the above-mentioned averaging process alone, the gain of the resonance frequency in the vertical direction and the front-back direction of the unsprung part of the vehicle does not always reach the maximum peak value as compared with the gain of the frequencies in the vicinity thereof due to noise or the like. There is a problem that it is not limited. Therefore, in this embodiment, following the averaging process described above, the following moving average process is performed in step 160.
【００２０】この移動平均処理は、ｎ番目の周波数のゲ
インＹn を以下の演算式によって求めることにより実施
される。This moving average processing is carried out by obtaining the gain Y n of the nth frequency by the following arithmetic expression.
【００２１】[0021]
【数１】Ｙn ＝（ｙn+1 ＋Ｙn-1 ）／２ つまり、移動平均処理では、ｎ番目の周波数のゲインＹ
n が、前回の演算結果におけるｎ＋１番目のゲインｙ
n+1 と既に演算されたｎ−１番目の周波数のゲインＹ
n-1 との平均値とされる。これにより、ＦＦＴ演算結果
は、滑らかに変化する波形を示すことになる。この移動
平均処理により求められた演算結果を図９に示す。## EQU1 ## Y n = (y n + 1 + Y n-1 ) / 2 That is, in the moving average processing, the gain Y of the nth frequency is obtained.
n is the (n + 1) th gain y in the previous calculation result
n + 1 and the gain Y of the n-1th frequency already calculated
It is an average value with n-1 . As a result, the FFT calculation result shows a waveform that changes smoothly. FIG. 9 shows the calculation result obtained by this moving average processing.
【００２２】なお、ここでの波形処理は、上記移動平均
処理に限らず、平均化処理後のＦＦＴ演算結果に対して
ローパスフィルタ処理を施しても良いし、或いは、ステ
ップ１３０のＦＦＴ演算を実施する前に、車輪速度ｖの
微分演算を行い、その微分演算結果に対してＦＦＴ演算
を実施してもよい。The waveform processing here is not limited to the moving average processing described above, but a low-pass filter processing may be performed on the FFT calculation result after the averaging processing, or the FFT calculation of step 130 is performed. Before this, the wheel speed v may be differentially calculated, and the FFT calculation may be performed on the differential calculation result.
【００２３】次に、ステップ１７０では、上記移動平均
処理によりスムージングされたＦＦＴ演算結果に基づい
て、車両のばね下の前後方向の共振周波数ｆを算出す
る。そしてステップ１８０では、予め正常なタイヤ空気
圧に対応して設定されている初期周波数ｆ0 からの低下
偏差（ｆ0 −ｆ）を求め、この低下偏差（ｆ0 −ｆ）と
所定偏差Δｆとを比較する。この所定偏差Δｆは、正常
なタイヤ空気圧に対応する初期周波数ｆ0 を基準とし
て、タイヤ空気圧の許容下限値（例えば１．４ｋｇ／ｍ
2 ）に対応して設定されている。従って、ステップ１８
０において低下偏差（ｆ0 −ｆ）が所定偏差Δｆを上回
ったと判定されると、タイヤの空気圧が許容下限値より
も低下したとみなして、ステップ１９０に進み、表示部
５によって運転者に対して警告表示を行う。Next, in step 170, the resonance frequency f in the unsprung front-rear direction of the vehicle is calculated based on the FFT calculation result smoothed by the moving average processing. Then, in step 180, a decrease deviation (f 0 −f) from the initial frequency f 0 set in advance corresponding to normal tire pressure is obtained, and this decrease deviation (f 0 −f) and the predetermined deviation Δf are calculated. Compare. This predetermined deviation Δf is based on the initial frequency f 0 corresponding to the normal tire pressure, and the lower limit of the tire pressure (for example, 1.4 kg / m 2).
It is set according to 2 ). Therefore, step 18
When it is determined that the decrease deviation (f 0 −f) exceeds the predetermined deviation Δf at 0, it is considered that the tire air pressure has decreased below the allowable lower limit value, the process proceeds to step 190, and the display unit 5 prompts the driver to inform the driver. To display a warning.
【００２４】なお、上述の例では、車両のばね下の前後
方向の共振周波数のみに基づいて、タイヤの空気圧の低
下を検知する例を示したが、これに代えて上下方向の共
振周波数のみに基づきタイヤ空気圧の低下を検知しても
良いし、前後方向及び上下方向の共振周波数の両者に基
づいて検知しても良い。In the above-described example, an example in which the decrease in tire air pressure is detected based only on the resonance frequency in the front and rear direction of the unsprung part of the vehicle is shown. Instead, only the resonance frequency in the vertical direction is detected. The decrease in tire air pressure may be detected based on the resonance frequency in the front-rear direction or the resonance frequency in the vertical direction.
【００２５】次に本発明の第２実施例について説明す
る。上述の第１実施例では、特にタイヤの空気圧が許容
下限値よりも低下したことを検知するようにしていた
が、第２実施例では、タイヤの空気圧自体を検知しよう
とするものである。Next, a second embodiment of the present invention will be described. In the first embodiment described above, it is particularly detected that the tire air pressure is lower than the allowable lower limit value, but in the second embodiment, the tire air pressure itself is detected.
【００２６】このため、第２実施例では、図１１に示す
ようなタイヤ空気圧と共振周波数との関係を各タイヤ毎
にマップとして記憶し、第１実施例と同様に共振周波数
ｆを算出して、この算出された共振周波数ｆからタイヤ
空気圧自体を直接推定する。Therefore, in the second embodiment, the relationship between the tire pressure and the resonance frequency as shown in FIG. 11 is stored as a map for each tire, and the resonance frequency f is calculated in the same manner as in the first embodiment. The tire air pressure itself is directly estimated from the calculated resonance frequency f.
【００２７】この第２実施例では、ＥＣＵ４における処
理内容の一部のみが上記第１実施例と異なり、その構成
は上記第１実施例と共通である。このため、構成の説明
は省略し、かつＥＣＵ４における処理内容の相違点のみ
を説明する。In the second embodiment, only a part of the processing contents in the ECU 4 is different from the first embodiment, and the configuration is common to the first embodiment. Therefore, the description of the configuration will be omitted, and only the difference in the processing content in the ECU 4 will be described.
【００２８】すなわち、第２実施例では、図１０に示す
第１実施例のフローチャートのステップ１８０を、図１
２に示す処理に変更する。図１２において、ステップ１
８２では、ステップ１７０において算出された車両のば
ね下の前後方向の共振周波数ｆを用いて、予め設定され
記憶されたマップに従って、対応するタイヤ空気圧Ｐを
算出する。そして、ステップ１８４において、算出され
たタイヤ空気圧Ｐと予め設定されるタイヤ空気圧の許容
下限値Ｐ0 とを比較し、算出されたタイヤ空気圧Ｐが許
容下限値Ｐ0 以下であるとき、ステップ１９０に進む。That is, in the second embodiment, step 180 of the flow chart of the first embodiment shown in FIG.
Change to the process shown in 2. In FIG. 12, step 1
At 82, the corresponding tire air pressure P is calculated according to the preset and stored map using the unsprung longitudinal resonance frequency f of the vehicle calculated at step 170. Then, in step 184, the calculated tire air pressure P is compared with a preset allowable lower limit value P 0 of the tire air pressure, and when the calculated tire air pressure P is equal to or lower than the allowable lower limit value P 0 , step 190 is performed. move on.
【００２９】なお、この第２実施例では、表示部５の表
示形態を代えて、ステップ１８２において算出したタイ
ヤ空気圧Ｐを各輪毎に直接表示するようにしても良い。
次に、本発明の第３実施例について説明する。In the second embodiment, the display form of the display unit 5 may be changed and the tire pressure P calculated in step 182 may be directly displayed for each wheel.
Next, a third embodiment of the present invention will be described.
【００３０】上述の第１実施例では、タイヤの振動周波
数成分を含む信号を出力するセンサとして車輪速度セン
サを用いていたが、第３実施例では図１３に示すように
車両のばね下部材（例えば、ロアアーム１０）に加速度
センサ１１を配置し、タイヤの振動周波数成分を含む信
号を出力するセンサとして加速度センサ１１を用いるも
のである。In the above-described first embodiment, the wheel speed sensor is used as the sensor that outputs the signal including the vibration frequency component of the tire, but in the third embodiment, as shown in FIG. 13, the unsprung member of the vehicle ( For example, the acceleration sensor 11 is arranged in the lower arm 10) and the acceleration sensor 11 is used as a sensor that outputs a signal including a vibration frequency component of the tire.
【００３１】車両のばね下の加速度を検出し、それに対
してＦＦＴ演算を実施することにより、車両のばね下の
上下方向及び前後方向の共振周波数を算出できることは
前述した通りである。しかも、加速度センサ１１を用い
る場合には、その検出信号を直接ＦＦＴ演算の対象とす
ることができるため、前述の第１実施例に比較してＥＣ
Ｕ４における演算処理を簡略化することができるという
メリットがある。As described above, the vertical and longitudinal resonance frequencies of the unsprung part of the vehicle can be calculated by detecting the acceleration of the unsprung part of the vehicle and performing the FFT calculation on the acceleration. Moreover, when the acceleration sensor 11 is used, the detection signal thereof can be directly used as the target of the FFT calculation, and therefore, the EC can be compared with the first embodiment described above.
There is an advantage that the arithmetic processing in U4 can be simplified.
【００３２】従って、この第３実施例では、図１０のフ
ローチャートのステップ１００に代えて、図１４に示す
処理を実行する。すなわち、図１４に示すように、ステ
ップ１０２において、加速度センサ１１から出力される
加速度信号の読み込みのみをを行えばよい。そして、こ
の読み込んだ加速度信号に対して、前述の第１実施例と
同様の信号処理を行う。Therefore, in the third embodiment, the process shown in FIG. 14 is executed instead of step 100 in the flowchart of FIG. That is, as shown in FIG. 14, in step 102, it is only necessary to read the acceleration signal output from the acceleration sensor 11. Then, the read acceleration signal is subjected to the same signal processing as in the first embodiment.
【００３３】次に、本発明の第４実施例について説明す
る。上述の第１実施例では、タイヤの振動周波数成分を
含む信号を出力するセンサとして車輪速度センサと用い
ていたが、第４実施例では車体（ばね上部材）とタイヤ
（ばね下部材）との相対変位を検出する車高センサ２０
を設置し、タイヤの振動周波数成分を含む信号を出力す
るセンサとして車高センサ２０を用いるものである。Next, a fourth embodiment of the present invention will be described. In the above-described first embodiment, the wheel speed sensor is used as the sensor that outputs the signal including the vibration frequency component of the tire, but in the fourth embodiment, the vehicle body (the sprung member) and the tire (the unsprung member) are combined. Vehicle height sensor 20 for detecting relative displacement
Is installed, and the vehicle height sensor 20 is used as a sensor that outputs a signal including a vibration frequency component of the tire.
【００３４】図１５に示すように、車高センサ２０を用
いる場合には、車高センサ２０の検出信号に対し、適当
なローパスフィルタ処理を施した上で、２回微分処理を
行う。これにより、車高センサ２０の検出信号は、車体
とタイヤとの相対加速度を示す信号となる。そして、こ
の相対加速度を示す信号に対して図１０のフローチャー
トのステップ１１０以降の処理を行うことで、前述の第
１実施例と同様に、タイヤ空気圧を検知することが可能
となる。As shown in FIG. 15, when the vehicle height sensor 20 is used, the detection signal of the vehicle height sensor 20 is subjected to an appropriate low-pass filter process and then subjected to twice differentiating process. As a result, the detection signal of the vehicle height sensor 20 becomes a signal indicating the relative acceleration between the vehicle body and the tire. Then, by performing the processing from step 110 onward in the flowchart of FIG. 10 for the signal indicating the relative acceleration, it becomes possible to detect the tire air pressure as in the first embodiment described above.
【００３５】次に、本発明の第５実施例について説明す
る。上述の第１実施例では、タイヤの振動周波数成分を
含む信号を出力するセンサとして車輪速度センサと用い
ていたが、第５実施例では図１６に示すように、車体
（ばね上部材）とタイヤ（ばね下部材）との間の荷重を
検出する荷重センサ３０を設置し、タイヤの振動周波数
成分を含む信号を出力するセンサとして荷重センサ３０
を用いるものである。Next, a fifth embodiment of the present invention will be described. In the above-described first embodiment, the wheel speed sensor is used as the sensor that outputs the signal including the vibration frequency component of the tire, but in the fifth embodiment, as shown in FIG. 16, the vehicle body (spring member) and the tire are used. A load sensor 30 that detects a load between the (unsprung member) and the load sensor 30 is provided as a sensor that outputs a signal including a tire vibration frequency component.
Is used.
【００３６】図１６において、荷重センサ３０は、荷重
に応じた電荷を発生する圧電素子から構成され、ショッ
クアブソーバのピストンロッドの内部に収納されてい
る。このため、荷重センサ３０は、ショックアブソーバ
の減衰力に応じた信号を出力する。この信号に対し、上
記第３実施例と同様の信号処理を施すことにより、タイ
ヤ空気圧を検知することも可能である。In FIG. 16, the load sensor 30 is composed of a piezoelectric element that generates electric charges according to the load, and is housed inside the piston rod of the shock absorber. Therefore, the load sensor 30 outputs a signal according to the damping force of the shock absorber. It is also possible to detect the tire pressure by subjecting this signal to the same signal processing as in the third embodiment.
【００３７】[0037]
【発明の効果】以上説明したように、本発明によれば、
タイヤの振動周波数成分を含む信号から共振周波数を抽
出し、この抽出された共振周波数に基づいて、タイヤの
空気圧の状態を検知する。ここで、共振周波数は、タイ
ヤのばね定数に応じて変化し、タイヤのばね定数は実質
的にタイヤの空気圧にのみ依存して変化する。従って、
本発明によれば、タイヤの空気圧を間接的に検知しなが
ら、その検知精度を向上することが可能となる。As described above, according to the present invention,
A resonance frequency is extracted from a signal including a vibration frequency component of the tire, and the tire air pressure state is detected based on the extracted resonance frequency. Here, the resonance frequency changes depending on the spring constant of the tire, and the spring constant of the tire changes substantially only depending on the air pressure of the tire. Therefore,
According to the present invention, it is possible to improve the detection accuracy while indirectly detecting the tire air pressure.
【図１】本発明の第１実施例の構成を示す構成図であ
る。FIG. 1 is a configuration diagram showing a configuration of a first embodiment of the present invention.
【図２】車両のばね下の加速度の周波数特性を示す特性
図である。FIG. 2 is a characteristic diagram showing frequency characteristics of unsprung acceleration of a vehicle.
【図３】タイヤの空気圧の変化による車両のばね下の上
下方向及び前後方向の共振周波数の変化の様子を示す特
性図である。FIG. 3 is a characteristic diagram showing how the resonance frequency of the unsprung part of the vehicle changes in the up-down direction and the front-rear direction due to changes in tire air pressure.
【図４】第１実施例のタイヤ空気圧の検知原理を示す説
明図である。FIG. 4 is an explanatory diagram showing the principle of tire pressure detection according to the first embodiment.
【図５】車輪速度センサの出力電圧波形を示す波形図で
ある。FIG. 5 is a waveform diagram showing an output voltage waveform of a wheel speed sensor.
【図６】車輪速度センサの検出信号に基づいて演算され
た車輪速度ｖの変動状態を示す波形図である。FIG. 6 is a waveform diagram showing a variation state of wheel speed v calculated based on a detection signal of a wheel speed sensor.
【図７】図６に示す波形の車輪速度ｖに対して周波数解
析演算を行った結果を示す特性図である。7 is a characteristic diagram showing a result of performing a frequency analysis calculation on the wheel speed v having the waveform shown in FIG.
【図８】第１実施例における平均処理を説明するための
説明図である。FIG. 8 is an explanatory diagram illustrating an averaging process according to the first embodiment.
【図９】第１実施例における移動平均処理を行った後の
周波数解析結果を示す特性図である。FIG. 9 is a characteristic diagram showing a frequency analysis result after performing a moving average process in the first example.
【図１０】第１実施例の電子制御装置の処理内容を示す
特性図である。FIG. 10 is a characteristic diagram showing processing contents of the electronic control unit of the first embodiment.
【図１１】本発明の第２実施例におけるタイヤ空気圧と
共振周波数との関係を示す特性図である。FIG. 11 is a characteristic diagram showing the relationship between tire pressure and resonance frequency in the second embodiment of the present invention.
【図１２】第２実施例と第１実施例との処理内容の相違
点を示すフローチャートである。FIG. 12 is a flowchart showing a difference in processing contents between the second embodiment and the first embodiment.
【図１３】本発明の第３実施例の構成を示す構成図であ
る。FIG. 13 is a configuration diagram showing a configuration of a third exemplary embodiment of the present invention.
【図１４】第３実施例と第１実施例との処理内容の相違
点を示すフローチャートである。FIG. 14 is a flowchart showing a difference in processing content between the third embodiment and the first embodiment.
【図１５】本発明の第４実施例の構成を示す構成図であ
る。FIG. 15 is a configuration diagram showing a configuration of a fourth exemplary embodiment of the present invention.
【図１６】本発明の第５実施例の構成を示す構成図であ
る。FIG. 16 is a configuration diagram showing a configuration of a fifth exemplary embodiment of the present invention.
１ タイヤ ２ 歯車 ３ ピックアップコイル ４ 電子制御装置（ＥＣＵ） ５ 表示部 1 Tire 2 Gear 3 Pickup Coil 4 Electronic Control Unit (ECU) 5 Display
Claims (6)
分を含む信号を出力する出力手段と、 前記タイヤの振動周波数成分を含む信号から共振周波数
を抽出する抽出手段と、 前記共振周波数に基づいて、前記タイヤの空気圧の状態
を検知する検知手段とを備えることを特徴とするタイヤ
空気圧検知装置。1. When the vehicle is traveling, output means for outputting a signal containing a vibration frequency component of the tire, extraction means for extracting a resonance frequency from the signal containing the vibration frequency component of the tire, and based on the resonance frequency. A tire air pressure detection device, comprising: a detection unit configured to detect an air pressure state of the tire.
た信号を出力する車輪速度センサであることを特徴とす
る請求項１記載のタイヤ空気圧検知装置。2. The tire air pressure detection device according to claim 1, wherein the output means is a wheel speed sensor that outputs a signal corresponding to the rotation speed of the wheel.
向の共振周波数と前後方向の共振周波数との少なくとも
一方を抽出することを特徴とする請求項１記載のタイヤ
空気圧検知装置。3. The tire pressure detecting device according to claim 1, wherein the extracting means extracts at least one of a vertical resonance frequency and a front-rear resonance frequency of the unsprung portion of the vehicle.
振周波数を基準共振周波数として記憶しておき、この基
準共振周波数に対する抽出された共振周波数の変化量か
ら前記タイヤの空気圧の低下を検知することを特徴とす
る請求項１記載のタイヤ空気圧検知装置。4. The detection means stores in advance a resonance frequency at normal air pressure as a reference resonance frequency, and detects a decrease in the tire air pressure from the amount of change in the extracted resonance frequency with respect to the reference resonance frequency. The tire air pressure detection device according to claim 1, wherein
圧と共振周波数との関係を記憶しておき、この記憶され
た関係に基づいて抽出された共振周波数より前記タイヤ
の空気圧を推定することを特徴とする請求項１記載のタ
イヤ空気圧検知装置。5. The detection means stores the relationship between the tire air pressure and the resonance frequency in advance, and estimates the tire air pressure from the resonance frequency extracted based on the stored relationship. The tire air pressure detection device according to claim 1, which is characterized in that.
気圧が下限空気圧よりも低下したことが検知されたと
き、運転者に対して警報を行う警報手段を備えることを
特徴とする請求項１記載のタイヤ空気圧検知装置。6. The alarm means according to claim 1, further comprising an alarm means for issuing an alarm to a driver when the air pressure of the tire is detected to be lower than a lower limit air pressure by the detection means. Tire pressure detection device.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29462291A JP2836652B2 (en) | 1991-11-11 | 1991-11-11 | Tire pressure detector |
| DE1992633018 DE69233018T2 (en) | 1991-11-11 | 1992-11-10 | Tire air pressure detection device using a resonance frequency and wheel speed sensor |
| EP97103562A EP0783982B1 (en) | 1991-11-11 | 1992-11-10 | Tire air pressure detecting device using a resonance frequency and wheel speed sensor |
| DE69226175T DE69226175T2 (en) | 1991-11-11 | 1992-11-10 | Tire pressure meter with the resonance frequency of the tire |
| PCT/JP1992/001457 WO1993010431A1 (en) | 1991-11-11 | 1992-11-10 | Tire pneumatic pressure sensor |
| EP92923005A EP0578826B1 (en) | 1991-11-11 | 1992-11-10 | Tire air pressure detecting device using a resonance frequency |
| US08/133,440 US5497657A (en) | 1991-11-11 | 1993-10-08 | Tire air pressure detecting device |
| US08/168,093 US5553491A (en) | 1991-11-11 | 1993-12-17 | Tire air pressure detecting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29462291A JP2836652B2 (en) | 1991-11-11 | 1991-11-11 | Tire pressure detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05133831A true JPH05133831A (en) | 1993-05-28 |
| JP2836652B2 JP2836652B2 (en) | 1998-12-14 |
Family
ID=17810140
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29462291A Expired - Fee Related JP2836652B2 (en) | 1991-11-11 | 1991-11-11 | Tire pressure detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2836652B2 (en) |
Cited By (35)
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| JPH0625743U (en) * | 1992-08-31 | 1994-04-08 | 日産ディーゼル工業株式会社 | Tire pressure detection device |
| EP0695653A1 (en) | 1994-08-04 | 1996-02-07 | Nippondenso Co., Ltd. | Tire resonance frequency detecting apparatus |
| EP0699546A1 (en) | 1994-06-06 | 1996-03-06 | Toyota Jidosha Kabushiki Kaisha | Wheel information estimating apparatus |
| US5531110A (en) * | 1993-07-30 | 1996-07-02 | Toyota Jidosha Kabushiki Kaisha | Method and apparatus for estimating disturbance acting on vehicle tired wheel based on wheel angular velocity and equation of state |
| EP0756951A1 (en) | 1995-08-04 | 1997-02-05 | Nippondenso Co., Ltd. | Tyre pneumatic pressure estimating apparatus |
| US5606122A (en) * | 1994-09-09 | 1997-02-25 | Nippondenso Co., Ltd. | Tire pneumatic pressure detector |
| DE19643879A1 (en) * | 1995-10-31 | 1997-05-07 | Aisin Seiki | Determining tyre inflation pressure of vehicle tyre using number of steps |
| US5662393A (en) * | 1994-11-02 | 1997-09-02 | Nippondenso Co., Ltd. | Braking force control device and method thereof |
| EP0895880A2 (en) | 1997-08-08 | 1999-02-10 | Denso Corporation | Apparatus for estimating tire air pressure |
| EP0897815A2 (en) | 1997-08-12 | 1999-02-24 | Sumitomo Rubber Industries Ltd. | Tyre air-pressure abnormality alarm device and method thereof |
| US5913241A (en) * | 1996-05-23 | 1999-06-15 | Toyota Jidosha Kabushiki Kaisha | Apparatus for estimating vehicle tire air pressure from not only tired wheel motion but also tire temperature |
| EP0925960A2 (en) | 1997-12-15 | 1999-06-30 | Denso Corporation | Tyre air pressure estimating apparatus |
| US6109099A (en) * | 1997-12-22 | 2000-08-29 | Aisin Seiki Kabushiki Kaisha | Method and apparatus for detecting air pressure in a tire using a basic wavelet function localized in time |
| EP1080952A2 (en) | 1999-08-30 | 2001-03-07 | Denso Corporation | Tire pressure warning device |
| EP1086834A2 (en) | 1999-09-21 | 2001-03-28 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Device for estimating tire air pressure state, and device for detecting wheel speed signal frequency |
| JP2005300254A (en) * | 2004-04-08 | 2005-10-27 | Advics:Kk | Wheel load estimating device and wheel load estimation method |
| US7203612B2 (en) | 2003-07-08 | 2007-04-10 | Continental Teves Ag & Co., Ohg | Method for determining internal pressure of a vehicle tire |
| US7205886B2 (en) | 2003-06-19 | 2007-04-17 | Honda Motor Co., Ltd. | Tire pressure monitoring system |
| US7263458B2 (en) * | 2003-07-07 | 2007-08-28 | Nira Dynamics Ab | Tire pressure estimation |
| US7301444B2 (en) | 2002-09-10 | 2007-11-27 | Sumitomo Rubber Industries, Ltd. | Method and apparatus for alarming decrease in tire air-pressure and threshold changing program |
| JP2010091396A (en) * | 2008-10-08 | 2010-04-22 | Sumitomo Rubber Ind Ltd | Device and method for detecting decrease in tire air pressure, and program for detecting decrease in tire air pressure |
| JP2010120621A (en) * | 2008-10-20 | 2010-06-03 | Sumitomo Rubber Ind Ltd | Device and method of detecting tire pressure drop, and tire pressure drop detection program |
| JP2011102074A (en) * | 2009-11-10 | 2011-05-26 | Sumitomo Rubber Ind Ltd | Pressure reduction sensitivity estimating device and method of resonance frequency of tire and pressure reduction sensitivity estimating program of resonance frequency of tire |
| WO2011099579A1 (en) * | 2010-02-12 | 2011-08-18 | トヨタ自動車株式会社 | Tire state determination device |
| JP2012132873A (en) * | 2010-12-24 | 2012-07-12 | Nagoya Electric Works Co Ltd | Tire determination device, tire determination method and tire determination program |
| US8494704B2 (en) | 2007-03-16 | 2013-07-23 | Nira Dynamics Ab | Tire pressure classification based tire pressure monitoring |
| US8554498B2 (en) | 2007-03-16 | 2013-10-08 | Nira Dynamics Ab | Method, system and computer program for estimation of the pressure |
| JP2014193667A (en) * | 2013-03-28 | 2014-10-09 | Jtekt Corp | Vehicle steering device |
| US20140372006A1 (en) * | 2013-06-17 | 2014-12-18 | Infineon Technologies Ag | Indirect tire pressure monitoring systems and methods using multidimensional resonance frequency analysis |
| US9016116B1 (en) | 2013-10-07 | 2015-04-28 | Infineon Technologies Ag | Extraction of tire characteristics combining direct TPMS and tire resonance analysis |
| US9079462B2 (en) | 2007-03-16 | 2015-07-14 | Nira Dynamics Ab | System, method and computer program of estimating tire pressure deviations |
| CN105437880A (en) * | 2015-12-23 | 2016-03-30 | 安徽安凯汽车股份有限公司 | Tire pressure monitoring system and method |
| KR20200043193A (en) * | 2018-10-17 | 2020-04-27 | 현대자동차주식회사 | Apparatus and method for monitoring tire pressure of vehicle |
| JP2020183180A (en) * | 2019-05-08 | 2020-11-12 | トヨタ自動車株式会社 | Vehicle gradient estimation device |
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| JP3362522B2 (en) | 1994-09-07 | 2003-01-07 | 株式会社デンソー | Tire pressure detector |
| JP3769459B2 (en) | 2000-10-13 | 2006-04-26 | 株式会社豊田中央研究所 | Tire burst prediction device |
| JP3657876B2 (en) | 2000-11-27 | 2005-06-08 | アイシン精機株式会社 | Tire pressure estimation device |
| JP3872367B2 (en) | 2002-03-26 | 2007-01-24 | トヨタ自動車株式会社 | Tire quantity estimation device |
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1991
- 1991-11-11 JP JP29462291A patent/JP2836652B2/en not_active Expired - Fee Related
Cited By (47)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0625743U (en) * | 1992-08-31 | 1994-04-08 | 日産ディーゼル工業株式会社 | Tire pressure detection device |
| US5531110A (en) * | 1993-07-30 | 1996-07-02 | Toyota Jidosha Kabushiki Kaisha | Method and apparatus for estimating disturbance acting on vehicle tired wheel based on wheel angular velocity and equation of state |
| US6142026A (en) * | 1994-06-06 | 2000-11-07 | Toyota Jidosha Kabushiki Kaisha | Wheel information estimating apparatus |
| EP0699546A1 (en) | 1994-06-06 | 1996-03-06 | Toyota Jidosha Kabushiki Kaisha | Wheel information estimating apparatus |
| EP0695653A1 (en) | 1994-08-04 | 1996-02-07 | Nippondenso Co., Ltd. | Tire resonance frequency detecting apparatus |
| US5596141A (en) * | 1994-08-04 | 1997-01-21 | Nippondenso Co., Ltd. | Tire resonance frequency detecting system having inter-wheel noise elimination and method for the same |
| US5606122A (en) * | 1994-09-09 | 1997-02-25 | Nippondenso Co., Ltd. | Tire pneumatic pressure detector |
| US5662393A (en) * | 1994-11-02 | 1997-09-02 | Nippondenso Co., Ltd. | Braking force control device and method thereof |
| US5753809A (en) * | 1995-08-04 | 1998-05-19 | Nippondenso Co., Ltd. | Tire pneumatic pressure estimating apparatus |
| EP0756951A1 (en) | 1995-08-04 | 1997-02-05 | Nippondenso Co., Ltd. | Tyre pneumatic pressure estimating apparatus |
| DE19643879A1 (en) * | 1995-10-31 | 1997-05-07 | Aisin Seiki | Determining tyre inflation pressure of vehicle tyre using number of steps |
| US5801305A (en) * | 1995-10-31 | 1998-09-01 | Aisin Seiki Kabushiki Kaisha | Method and apparatus for detecting a tire inflation pressure |
| US5913241A (en) * | 1996-05-23 | 1999-06-15 | Toyota Jidosha Kabushiki Kaisha | Apparatus for estimating vehicle tire air pressure from not only tired wheel motion but also tire temperature |
| EP0895880A2 (en) | 1997-08-08 | 1999-02-10 | Denso Corporation | Apparatus for estimating tire air pressure |
| EP0897815A2 (en) | 1997-08-12 | 1999-02-24 | Sumitomo Rubber Industries Ltd. | Tyre air-pressure abnormality alarm device and method thereof |
| US6323765B1 (en) | 1997-08-12 | 2001-11-27 | Sumitomo Rubber Industries, Ltd. | Tire air-pressure abnormality alarming device and method thereof |
| EP0925960A2 (en) | 1997-12-15 | 1999-06-30 | Denso Corporation | Tyre air pressure estimating apparatus |
| EP0925960A3 (en) * | 1997-12-15 | 2004-06-09 | Denso Corporation | Tyre air pressure estimating apparatus |
| US6109099A (en) * | 1997-12-22 | 2000-08-29 | Aisin Seiki Kabushiki Kaisha | Method and apparatus for detecting air pressure in a tire using a basic wavelet function localized in time |
| EP1080952A2 (en) | 1999-08-30 | 2001-03-07 | Denso Corporation | Tire pressure warning device |
| EP1086834A2 (en) | 1999-09-21 | 2001-03-28 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Device for estimating tire air pressure state, and device for detecting wheel speed signal frequency |
| US7301444B2 (en) | 2002-09-10 | 2007-11-27 | Sumitomo Rubber Industries, Ltd. | Method and apparatus for alarming decrease in tire air-pressure and threshold changing program |
| US7205886B2 (en) | 2003-06-19 | 2007-04-17 | Honda Motor Co., Ltd. | Tire pressure monitoring system |
| US7263458B2 (en) * | 2003-07-07 | 2007-08-28 | Nira Dynamics Ab | Tire pressure estimation |
| US7203612B2 (en) | 2003-07-08 | 2007-04-10 | Continental Teves Ag & Co., Ohg | Method for determining internal pressure of a vehicle tire |
| JP2005300254A (en) * | 2004-04-08 | 2005-10-27 | Advics:Kk | Wheel load estimating device and wheel load estimation method |
| US8554498B2 (en) | 2007-03-16 | 2013-10-08 | Nira Dynamics Ab | Method, system and computer program for estimation of the pressure |
| US9145033B2 (en) | 2007-03-16 | 2015-09-29 | Nira Dynamics Ab | Tire pressure classification based tire pressure monitoring |
| US9079462B2 (en) | 2007-03-16 | 2015-07-14 | Nira Dynamics Ab | System, method and computer program of estimating tire pressure deviations |
| US8494704B2 (en) | 2007-03-16 | 2013-07-23 | Nira Dynamics Ab | Tire pressure classification based tire pressure monitoring |
| JP2010091396A (en) * | 2008-10-08 | 2010-04-22 | Sumitomo Rubber Ind Ltd | Device and method for detecting decrease in tire air pressure, and program for detecting decrease in tire air pressure |
| JP2010120621A (en) * | 2008-10-20 | 2010-06-03 | Sumitomo Rubber Ind Ltd | Device and method of detecting tire pressure drop, and tire pressure drop detection program |
| JP2011102074A (en) * | 2009-11-10 | 2011-05-26 | Sumitomo Rubber Ind Ltd | Pressure reduction sensitivity estimating device and method of resonance frequency of tire and pressure reduction sensitivity estimating program of resonance frequency of tire |
| US9409453B2 (en) | 2010-02-12 | 2016-08-09 | Toyota Jidosha Kabushiski Kaisha | Tire state judging device |
| JP2011162138A (en) * | 2010-02-12 | 2011-08-25 | Toyota Motor Corp | Tire-state determination device |
| WO2011099579A1 (en) * | 2010-02-12 | 2011-08-18 | トヨタ自動車株式会社 | Tire state determination device |
| JP2012132873A (en) * | 2010-12-24 | 2012-07-12 | Nagoya Electric Works Co Ltd | Tire determination device, tire determination method and tire determination program |
| JP2014193667A (en) * | 2013-03-28 | 2014-10-09 | Jtekt Corp | Vehicle steering device |
| US20140372006A1 (en) * | 2013-06-17 | 2014-12-18 | Infineon Technologies Ag | Indirect tire pressure monitoring systems and methods using multidimensional resonance frequency analysis |
| US9527352B2 (en) * | 2013-06-17 | 2016-12-27 | Infineon Technologies Ag | Indirect tire pressure monitoring systems and methods using multidimensional resonance frequency analysis |
| US9016116B1 (en) | 2013-10-07 | 2015-04-28 | Infineon Technologies Ag | Extraction of tire characteristics combining direct TPMS and tire resonance analysis |
| US9841359B2 (en) | 2013-10-07 | 2017-12-12 | Infineon Technologies Ag | Extraction of tire characteristics combining direct TPMS and tire resonance analysis |
| CN105437880A (en) * | 2015-12-23 | 2016-03-30 | 安徽安凯汽车股份有限公司 | Tire pressure monitoring system and method |
| KR20200043193A (en) * | 2018-10-17 | 2020-04-27 | 현대자동차주식회사 | Apparatus and method for monitoring tire pressure of vehicle |
| JP2020183180A (en) * | 2019-05-08 | 2020-11-12 | トヨタ自動車株式会社 | Vehicle gradient estimation device |
| US20220292892A1 (en) * | 2021-03-12 | 2022-09-15 | Hyundai Motor Company | Control apparatus of vehicle, and operating method of the same, vehicle |
| US12333871B2 (en) * | 2021-03-12 | 2025-06-17 | Hyudai Motor Company | Control apparatus of vehicle, and operating method of the same, vehicle |
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