JP4237464B2 - Different diameter tire detector - Google Patents

Description

【００５７】
そして、この異径タイヤ装着判定条件の何れか一方が満足されなかった場合、条件不成立と判断して、ステップＳ９へ分岐し、前左車輪異径タイヤ装着判定タイマＦ_LＴＩＭＥをクリアして（Ｆ_LＴＩＭＥ←０）、ルーチンを抜ける。
【００５８】
一方、この異径タイヤ装着判定条件が全て満足された場合、異径タイヤ装着判定条件成立と判断して、ステップＳ１０へ進み、前左車輪異径タイヤ装着判定タイマＦ_LＴＩＭＥをインクリメントし（Ｆ_LＴＩＭＥ←Ｆ_LＴＩＭＥ＋１）、ステップＳ１１へ進み、前左車輪異径タイヤ装着判定タイマＦ_LＴＩＭＥの値と、設定時間ＴＩＭＥとを比較する。この設定時間ＴＩＭＥは、誤判定を防止するためのもので、予め実験などから求められている。
【００５９】
そして、Ｆ_LＴＩＭＥ≧ＴＩＭＥに達すると、ステップＳ１２へ分岐し、今回の対象車輪である前左車輪１０Ｌには、異径タイヤが装着されていると判断し、ステップＳ１３へ進む。又、Ｆ_LＴＩＭＥ＜ＴＩＭＥのときは、そのままステップＳ１３へ進む。
【００６０】
ステップＳ１３では、車速Ｖｓと設定車速Ｖｓｏとを比較する。この設定車速Ｖｓｏは、異径タイヤ装着状態であっても、トランスミッション２、トランスファ３、リヤデファレンシャル７等の駆動系に悪影響を及ぼさない場合には、通常タイヤ装着時と同等の制御を行なうことで走行性能を確保することのできる車速の許容値であり、予め実験などから求めて設定されている。
【００６１】
そして、Ｖｓ≦Ｖｓｏのときは、ステップＳ１４へ分岐し、通常タイヤ装着時制御を実行して、ルーチンを抜ける。又、Ｖｓ＞Ｖｓｏのときは、ステップＳ１５へ進み、異径タイヤ装着時制御を実行して、ルーチンを抜ける。
【００６２】
尚、ステップＳ１３において判定する駆動系に悪影響を及ぼさない条件としては、車速以外に、
１）トランスミッション入力エンジントルクが所定以下であること
２）スロットル開度が所定以下であること
３）トランスファ３から前後車輪側へ伝達されるトルクが所定以下であること等の条件を加えるようにしても良い。
【００６３】
ステップＳ１５で処理される異径タイヤ装着時制御が、例えば４輪駆動車の駆動力配分制御の場合、トランスファ３に設けられているトランスファクラッチ５を開放動作させて、前輪或いは後輪側へ過剰なトルクが伝達されることを防止する制御が行なわれる。
【００６４】
尚、インストルメントパネルに４輪のタイヤ表示ランプを配設し、異径タイヤを装着する車輪が検出された場合、当該車輪に対応するタイヤ表示ランプを点灯させて異径タイヤが装着されていることを運転者に報知するようにしても良い。又、タイヤ表示ランプを点灯させることで、空気圧不足を運転者に知らせることも可能となる。
【００６５】
【発明の効果】
以上、説明したように本発明によれば、異径タイヤが１つの車輪のみ成らず、２つの車輪に装着されている場合であっても、異径タイヤを特定することができるため、異径タイヤ装着の有無をより正確に検出することができる。
【図面の簡単な説明】
【図１】４輪駆動車の動力伝達系の概略構成図
【図２】シグナルロータと車輪速センサとの概略構成図
【図３】異径タイヤ検出ルーチンを示すフローチャート（その１）
【図４】異径タイヤ検出ルーチンを示すフローチャート（その２）
【符号の説明】
１０Ｌ 前左車輪
１０Ｒ 前右車輪
１１Ｌ 後左車輪
１１Ｒ 後右車輪
２７Ｌ，２７Ｒ，２８Ｌ，２８Ｒ 車輪速センサ（車輪速検出手段）
ＡＦＲＶＨ 前後車輪速比
ＡＬＲＶＨ 左右車輪速比
Ｆ_LRＶｗ，ＦＲ_LＶｗ，ＦＲ_RＶｗ，Ｒ_LRＶｗ 平均車輪速
Ｆ_RＶｗ，Ｆ_LＶｗ，Ｒ_RＶｗ，Ｒ_LＶｗ 車輪速
Ｆ_LRＶＨ 前左右車輪速比
Ｒ_LRＶＨ 後左右車輪速比
ＴＩＭＥ 設定時間
ＶＨＨｉ 車輪速比上位値
ＶＨＬｏ 車輪速比下位値[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a different diameter tire detection device that identifies a wheel on which a different diameter tire is mounted based on a wheel speed detected by a wheel speed sensor.
[0002]
[Prior art]
The tires are punctured and fitted with temporary (tempered) tires (emergency tires), tires with different diameters from the designated tires, or the tire diameter is apparently small due to insufficient tire air pressure. If a tire with a smaller diameter than a normal standard tire (hereinafter referred to as “different diameter tire”) is installed, the wheel is smaller than a wheel with a normal standard tire. The wheel speed detected by the speed sensor is detected at a speed higher than the actual speed.
[0003]
The wheel speed of each wheel detected by the wheel speed sensor is a driving force distribution control device that distributes the driving force of the four-wheel drive vehicle to the front and rear wheels, and a VDC (Vehicle Dynamic Control) device that controls the braking force for the traveling vehicle (“VSC (It is also referred to as “Vehicle Stability Control” device). However, in the driving force distribution control of a four-wheel drive vehicle, the drive wheel on which the tires of different diameter are mounted always slips. Therefore, the control for unnecessarily increasing the fastening force of the transfer clutch that sets the distribution of the driving force to the front and rear wheels is performed. Further, in the VDC control, control for applying a braking force to a wheel on which a tire having a different diameter is mounted is performed in order to ensure stable running.
[0004]
Therefore, when mounting of different diameter tires is detected, the driving force distribution control device of the four-wheel drive vehicle releases the fastening force of the transfer clutch, and the VDC device stops the brake control. .
[0005]
By the way, generally, the presence or absence of different diameter tires is determined based on the wheel speed detected by the wheel speed sensor provided corresponding to each wheel.
[0006]
For example, in Japanese Patent Application Laid-Open No. 2002-79843, a relative calculation value indicating a relative relationship between wheel speeds of front wheels and rear wheels is calculated from a speed difference between an average wheel speed of front left and right wheels and an average wheel speed of rear left and right wheels. A description is disclosed in which a diameter difference ratio is calculated from the average of the relative calculation values, and whether or not different diameter tires are mounted is determined based on the diameter difference ratio.
[0007]
[Patent Document 1]
JP 2002-79843 A
[Problems to be solved by the invention]
However, in the technology disclosed in the above-mentioned publication, only the presence / absence of tires of different diameters is detected based on the average wheel speed of the front left and right wheels and the average wheel speed of the rear left and right wheels. Since it is not specified whether or not different diameter tires are mounted on the wheels, for example, even when the tires are recognized as different diameter tires due to insufficient air pressure, the driver can be notified of the tires with insufficient air pressure. Can't do it, causing inconvenience.
[0009]
Furthermore, for example, when different diameter tires are mounted on one of the front wheels and one of the rear wheels, the difference in speed between the front and rear wheels is eliminated, so that the mounting state of the different diameter tires cannot be detected. There is.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a different diameter tire detection device that can be specified even when a different diameter tire is not only one wheel but is mounted on two wheels. And
[0013]
[Problems to be solved by the invention]
The first tire detecting device for different diameters is provided on each wheel of the vehicle and detects the wheel speed of each wheel, and the wheel speed detected by each wheel speed detecting means. The left and right wheel speed ratio based on the average value of the front and rear left wheel speeds and the average value of the front and rear right wheel speeds, and the front and rear left and right wheel speed average values and the rear left and right wheel speed average values A wheel speed ratio calculating means for calculating a wheel speed ratio, and one of the two wheel speed ratios is within a preset wheel speed ratio region when different diameter tires are mounted, and the other wheel speed ratio is 1 or 1 And a different diameter tire detecting means for identifying two wheels on which different diameter tires are mounted based on the wheel speed for calculating the one wheel speed ratio.
[0014]
In such a configuration, the left and right wheels based on the average value of the wheel speeds of the front and rear left wheels and the average value of the wheel speeds of the front and rear right wheels based on the wheel speeds detected by the wheel speed detection means provided on each wheel of the vehicle. Calculate the front / rear wheel speed ratio based on the speed ratio and the average wheel speed of the front left and right wheels and the average wheel speed of the rear left and right wheels. When one wheel speed ratio is within the wheel speed ratio region when different diameter tires are mounted and the other wheel speed ratio shows a value close to 1 or 1, Based on the four wheel speeds used when calculating one wheel speed ratio, two wheels on which different diameter tires are mounted are identified from the wheels that have detected the respective wheel speeds.
[0015]
Further, the second different diameter tire detecting device is provided on each wheel of the vehicle and detects the wheel speed of each wheel, and the wheel speed detected by each wheel speed detecting means. Based on the front left and right wheel speed ratio of the front left and right wheels, the rear left and right wheel speed ratio of the rear left and right wheels, the average wheel speed of the front left and right wheels and the average wheel speed of the rear left and right wheels Both the front left / right wheel speed ratio and the rear left / right wheel speed ratio are within a preset wheel speed ratio region when a different diameter tire is mounted and the front / rear wheel speed is calculated. When the ratio indicates 1 or a value close to 1, the front left rear right wheel or the front right rear left wheel on which different diameter tires are mounted based on the front left / right wheel speed ratio and the rear left / right wheel speed ratio. It is provided with the different diameter tire detection means which specifies two wheels.
[0016]
In such a configuration, based on the wheel speed detected by the wheel speed detecting means provided on each wheel of the vehicle, the front left and right wheel speed ratio of the front left and right wheels, the rear left and right wheel speed ratio of the rear left and right wheels, Calculate the front / rear wheel speed ratio based on the average wheel speed of the front left / right wheels and the average wheel speed of the rear left / right wheels, and both the front left / right wheel speed ratio and the rear left / right wheel speed ratio are different tires. The wheel speed ratio of both wheels is within the wheel speed ratio area when different diameter tires are mounted, and the front and rear wheel speed ratio is 1 or close to 1. The front left / right wheel speed ratio and the rear left / right wheel speed ratio are calculated based on the four wheel speeds used to calculate the respective wheel speeds before the tires with different diameters are mounted. Two wheels, the left rear right wheel or the front right rear left wheel, are specified.
[0017]
In this case, preferably, 1) the different diameter tire detecting means determines that the different diameter tire is mounted when the wheel on which the different diameter tire is mounted is specified and the state continues for a set time. And
[0018]
In the 2) above different-diameter tire detecting means checks whether or not the different-diameter tire determination permission condition can be detected correctly mounting the different-diameter tire based on the driving state of the vehicle, the different-diameter tire determination permission condition is not satisfied If not, the different diameter tire detection process is stopped.
[0019]
3) In the above different-diameter tire detection means, after determining that different diameter tires, examine the release condition of the different-diameter tire mounted state, when said cancellation condition is satisfied cancels the determination result of the different-diameter tires It is characterized by that.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a power transmission system of a four-wheel drive vehicle. In the following, transfer control for controlling the distribution of driving force to the front and rear wheels is taken as an example, and tires of different diameters are mounted based on the wheel speed detected by a wheel speed sensor which is an example of a wheel speed detection means. A case where a wheel is detected will be described.
[0021]
Reference numeral 1 in FIG. 1 denotes an engine, and a transfer 3 is integrally connected to a rear portion of a transmission 2 connected to an output shaft of the engine 1. The transfer 3 is connected to the planetary gear mechanism 4 to which the driving force from the transmission 2 is input, and the planetary gear mechanism 4 is connected to the planetary gear mechanism 4. The transfer torque is electronically controlled by a transfer control unit (TCU) 20 as an arithmetic unit described later. A center differential is constituted by the transfer clutch 5 formed of a plate clutch, and the driving force of the engine 1 is shifted to a predetermined speed by the transmission 2 and then distributed to the front wheel side and the rear wheel side via the transfer 3.
[0022]
In the present embodiment, the output side of the transmission 2 is connected to the ring gear of the planetary gear mechanism 4, and a carrier that rotatably supports a pinion that meshes with the ring gear and the sun gear is connected to the rear differential 7 via the propeller shaft 6. ing.
[0023]
The carrier of the planetary gear mechanism 4 is connected to the clutch drum of the transfer clutch 5, and the sun gear is connected to the clutch hub of the transfer clutch 5 and is also connected to the front differential 9 through the front drive shaft 8.
[0024]
The transfer clutch 5 includes a drive mechanism that presses a clutch plate, which is connected to and separated from a clutch drum and a clutch hub, via a carrier, for example, an electromagnetic drive mechanism including an electromagnetic clutch and a torque amplifying cam. The fastening torque is controlled by controlling the excitation current of the electromagnetic drive mechanism.
[0025]
The driving force input from the transmission 2 to the planetary gear mechanism 4 is transmitted from the carrier to the rear left and right wheels 11L and 11R via the rear differential 7, and the difference between the carrier and the sun gear according to the fastening force of the transfer clutch 5 is transmitted. The dynamic output is transmitted to the front left and right wheels 10L and 10R via the front differential 9. That is, when the transfer clutch 5 is in the fully engaged state, the carrier and the sun gear are integrally fixed, and the torque is evenly distributed to the front wheel side and the rear wheel side. When the transfer clutch 5 is in the released state, the torque distribution of the rear wheel is deviated. It becomes.
[0026]
The fastening torque of the transfer clutch 5 is electronically controlled by a transfer control unit (TCU) 20 that is configured around a microcomputer. The transfer control unit 20 receives signals from various sensors and switches for detecting the engine operating state and the vehicle traveling state, control signals from other control units, and the like, and instructs fastening torque based on these signals. Calculate the value.
[0027]
As shown in FIG. 1, a signal input to the TCU 20 includes a throttle opening sensor 22 that detects the opening of the throttle valve, a brake switch 23 that is turned on when the brake pedal is depressed, and a signal that is turned on when the hand brake lever is pulled. Each signal from the operating hand brake switch 24, the lateral acceleration sensor 25 for detecting the lateral acceleration of the vehicle, the ABS operation signal from the ABS control unit (ABS_ECU) 30, and the engine control unit (E / G_ECU) 31 An engine speed signal or the like is input.
[0028]
Reference numeral 26 denotes a signal rotor that rotates integrally with each of the wheels 10R, 10L, 11R, and 11L, and wheel speed sensors 27R, 27L, 28R, and 28L configured by electromagnetic pickups are close to the outer periphery of each signal rotor 26. The pulse signals from the wheel speed sensors 27R, 27L, 28R, and 28L are input to the TCU 20 respectively.
[0029]
As shown in FIG. 2, a plurality of teeth are formed on the outer periphery of each signal rotor 26 at equal intervals. In each wheel speed sensor 27R, 27L, 28R, 28L, a change in magnetic field generated when the teeth pass, etc. Is detected and a sine wave pulse signal is output to the TCU 20. In the TCU 20, after the input pulse signal is shaped into a predetermined waveform, the wheel speeds F_RVw, F_LVw, R_RVw, R_LVw of the wheels 10R, 10L, 11R, 11L are calculated based on the period of the pulse signal.
[0030]
The TCU 20 controls the fastening force of the transfer clutch 5 based on each input signal. When the fastening force of the transfer clutch 5 is increased, the differential lock state is established, and when the fastening force of the transfer clutch 5 is released, the driving force is distributed to the front and rear wheels according to the distribution ratio set by the planetary gear mechanism 4.
[0031]
Further, the TCU 20 checks whether or not different diameter tires are mounted based on pulse signals output from the wheel speed sensors 27R, 27L, 28R, and 28L.
[0032]
This different diameter tire detection process is performed according to the different diameter tire detection routine shown in FIGS. In the following description, for the sake of convenience, the front left wheel 10L will be described as a representative of the wheels for detecting the mounting of different-diameter tires, and description of the other wheels 10R, 11L, and 11R will be omitted.
[0033]
This routine is executed every predetermined time. First, in step S1, each wheel 10L is based on a pulse signal from the wheel speed sensors 27L, 27R, 28L, 28R provided in the wheels 10L, 10R, 11L, 11R. , 10R, 11L, 11R wheel speeds F_LVw, F_RVw, R_LVw, R_RVw are calculated, and in the subsequent step S2, the wheel speeds F_LVw, R_LVw of the left and right front and rear wheels 10L, R_LVw are average wheel speeds FR_LVw (FR_LVw ← (F_LVw + R_LVw / R2 ) And the average wheel speeds FR_RVw (FR_RVw ← (F_RVw + R_RVw) / 2) of the wheel speeds F_RVw and R_RVw of the right and left front wheels 10R and 11R, and in step S3, the wheel speeds F_LVw, F_RVw average wheel speed F_LRVw (F_LRVw ← (F_LVw + F_RVw) / 2) and rear left and right wheels 11L, 11R wheel speed R_LVw, average wheel speed R_LRVw (R_LRVw ← (R_LVw + R_RVw) / 2) of R_RVw are calculated.
[0034]
In step S4, based on the wheel speeds calculated in steps S2 and S3, the front left / right wheel speed ratio F_LRVH, the rear left / right wheel speed ratio R_LRVH, the left / right wheel speed ratio ALRVH, and the front / rear wheel speed ratio AFRVH are calculate.
[0035]
F_LRVH ← F_LVw / F_RVw
R_LRVH ← R_LVw / R_RVw
ALRVH ← FR_LVw / FR_RVw
AFRVH ← F_LRVw / R_LRVw
[0036]
Next, in step S5, it is checked whether or not it is determined that the front left wheel 10L is in the “different diameter tire wearing state” at the time of the previous routine execution. It is checked whether or not the “mounting state” release condition is satisfied. The condition for canceling the "different diameter tire wearing state" is to cancel the "different diameter tire wearing state" as long as it does not interfere with running even if the different tire mounting is actually installed. By shifting to the control at the time of tire mounting, the driving performance is to be ensured. The conditions for canceling the “different tire mounted state” in the present embodiment are as follows.
[0037]
1) No acceleration driving 2) No deceleration driving or no stopping 3) ABS or other traction control system is inactive 4) No turning 5) Sensors / switches to detect these 6) Each wheel speed F_RVw, F_LVw, R_RVw, R_LVw shows almost the same value 7) The vehicle speed is equal to or higher than the vehicle speed at which no slip occurs when starting,
[0038]
1) Whether the vehicle is accelerating or not is determined based on the throttle opening detected by the throttle opening sensor 22, and if the throttle opening is equal to or less than the set opening, it is determined that the vehicle is not accelerating.
[0039]
2) Whether or not the vehicle is decelerating is determined based on the state of the brake switch 23. If the brake switch 23 is in the brake-released state, it is determined that the vehicle is not decelerating. Whether or not the vehicle is stopped is determined based on the state of the handbrake switch 24. If the handbrake switch 24 is in the OFF state of the handbrake, it is determined that the vehicle is not stopped.
[0040]
3) Whether or not ABS and other traction control systems are inactive is determined based on the operation signal of each control system.
[0041]
4) Whether or not the vehicle is turning is determined based on, for example, the lateral acceleration detected by the lateral acceleration sensor 25 or the yaw rate detected by the yaw rate sensor (not shown) when the inner ring is likely to slip. .
[0042]
5) Whether the operation of the sensors / switches is normal is determined based on a signal from another failure diagnosis control unit.
[0043]
6) Whether or not the wheel speeds F_RVw, F_LVw, R_RVw, and R_LVw indicate substantially the same value is determined based on the wheel speed ratios F_LRVH, R_LRVH, ALRVH, and AFRVH calculated in step S4. , It is determined that the wheel speeds F_RVw, F_LVw, R_RVw, and R_LVw indicate substantially the same value.
[0044]
7) Whether or not a start-time slip has occurred is determined based on the wheel speeds of the other wheels 10L, 11R, and 11L or the vehicle speed detected by the vehicle speed sensor, and each wheel speed or vehicle speed is set to a set vehicle speed (for example, 10 [Km / h]) or more, it is determined that no slip has occurred when starting.
[0045]
If at least one of the release conditions described above is not satisfied, the process jumps to step S15 and the control at the time of mounting the different-diameter tire is continued. On the other hand, if all of the cancellation conditions are satisfied, the process jumps to step S14, the control at the time of mounting the different diameter tire is canceled, and the control at the time of normal tire mounting is executed.
[0046]
As described above, in the present embodiment, even after it is determined that the tire is in a different diameter tire mounting state, when the release condition is satisfied during the subsequent routine execution, the control for different diameter tire mounting is canceled, Since the control is shifted to the normal tire mounting control, the running performance when the different diameter tire is mounted can be improved and the erroneous determination of the “different diameter tire mounting state” can be prevented.
[0047]
Even if the release condition is satisfied, if the state has not continued for a predetermined time, it may be determined that the different diameter tire release condition is not satisfied, and the process may jump to step S15. By providing a delay time, it is possible to detect the mounted state of the different-diameter tire with higher accuracy.
[0048]
On the other hand, in step S5, when the “different tire mounting state” of the front left wheel 10L is not detected during the previous routine execution, that is, when it is determined that a normal tire is mounted on the front left wheel 10L. Advances to step S7 and checks whether or not the different diameter tire determination permission condition is satisfied. This different diameter tire determination permission condition is the same as the above-mentioned “different diameter tire mounted state” cancellation conditions 1) to 5). If all of these conditions are satisfied, the process proceeds to step S8, and at least If one is not satisfied, the process proceeds to step S9, the front left wheel different diameter tire wearing determination timer F_LTIME is cleared (F_LTIME ← 0), and the routine is exited.
[0049]
On the other hand, if it progresses to step S8, it will be investigated whether the different diameter tire is mounted | worn with the front left wheel 10L according to the different diameter tire mounting determination conditions shown below.
[0050]
1) VHHi (Wheel speed ratio determination upper value) ≧ F_LRVH ≧ VHLo (Wheel speed ratio determination lower value)
2) About 1.1 ≧ R_LRVH ≧ about 0.9
[0051]
Condition 1) is that the front left / right wheel speed ratio F_LRVH is a wheel speed ratio (differential rotation) detected when a normal tire is mounted because the wheel speed of the target front left wheel 10L is faster than the wheel speed of the front right wheel 10R. The wheel speed ratio upper value VHHi is an abnormal left / right wheel speed ratio detected when one of the left and right wheels slips or slips, or a normal tire is mounted. Thus, the value is slightly smaller than the left / right wheel speed ratio generated during high speed traveling on a straight road, and is set in advance based on experiments and the like. Also, the wheel speed ratio lower value VHLo is set in advance based on experiments and the like, slightly smaller than the left and right wheel speed ratio that does not adversely affect the drive system of the transmission 2, the transfer 3, the rear differential 7, and the like. ing.
[0052]
Therefore, even when a different diameter tire is mounted on the front left wheel 10L, when VHLo> F_LRVH, the same control as when the normal tire is mounted is performed to perform the normal tire mounting control to ensure the running performance. .
[0053]
The front left / right wheel speed ratio F_LRVH is F_LRVH ← F_LVw (front left wheel) / F_RVw (front right wheel speed). The front left / right wheel speed ratio F_LRVH is F_LRVH ← F_RVw (front right wheel) / In the case of F_LVw (front left wheel speed), condition 1) is
1) 1 / VHLo (wheel speed ratio lower value) ≧ F_LRVH ≧ 1 / VHHi (wheel speed ratio upper value)
It becomes.
[0054]
On the other hand, the condition 2) is to check whether or not a wheel speed difference has occurred between the rear left and right wheels 11L and 11R. When the wheel speed difference has not occurred, a value approximate to 1 is shown. In this embodiment, the area is set to about 1.1 to 0.9, but this area can be changed as appropriate.
[0055]
In the present embodiment, the detection target of the different-diameter tire is the front left wheel 10L, but the detection target is the same even if the front right wheel 10R, the rear left wheel 11L, and the rear right wheel 11R. In this embodiment, whether the tires with different diameters are mounted on the two wheels, the front left and right wheels 10L and 10R, the rear left and right wheels 11L and 11R, the front left rear right wheels 10L and 11R, and the front right rear left wheels 10R and 11L. Whether or not can also be detected. The different diameter tire mounting determination conditions in this case are as shown in Table 1.
[0056]
[Table 1]

[0057]
If any one of the different diameter tire mounting determination conditions is not satisfied, it is determined that the condition is not satisfied, and the process branches to step S9 to clear the front left wheel different diameter tire mounting determination timer F_LTIME (F_LTIME ← 0) Exit the routine.
[0058]
On the other hand, if all the different diameter tire mounting determination conditions are satisfied, it is determined that the different diameter tire mounting determination conditions are satisfied, the process proceeds to step S10, and the front left wheel different diameter tire mounting determination timer F_LTIME is incremented (F_LTIME ← F_LTIME + 1). ), The process proceeds to step S11, and the value of the front left wheel different diameter tire wearing determination timer F_LTIME is compared with the set time TIME. The set time TIME is for preventing erroneous determination, and is obtained in advance from experiments or the like.
[0059]
When F_LTIME ≧ TIME is reached, the process branches to step S12, where it is determined that a different diameter tire is attached to the front left wheel 10L that is the current target wheel, and the process proceeds to step S13. If F_LTIME <TIME, the process proceeds to step S13.
[0060]
In step S13, the vehicle speed Vs is compared with the set vehicle speed Vso. This set vehicle speed Vso can be controlled by performing the same control as that for normal tires when the drive system such as the transmission 2, the transfer 3, the rear differential 7 and the like is not adversely affected even when different diameter tires are mounted. It is an allowable value of the vehicle speed that can ensure the running performance, and is set in advance by experiments.
[0061]
Then, when Vs ≦ Vso, the process branches to step S14, the normal tire wearing control is executed, and the routine is exited. Further, when Vs> Vso, the process proceeds to step S15 to execute the control at the time of mounting the different-diameter tire, and the routine is exited.
[0062]
As a condition that does not adversely affect the drive system determined in step S13, in addition to the vehicle speed,
1) The transmission input engine torque must be less than the predetermined value 2) The throttle opening must be less than the predetermined value 3) The torque transmitted from the transfer 3 to the front and rear wheels should be less than the predetermined value. Also good.
[0063]
If the control at the time of mounting the different-diameter tire processed in step S15 is, for example, driving force distribution control of a four-wheel drive vehicle, the transfer clutch 5 provided in the transfer 3 is opened and excessively moved to the front wheel or rear wheel side. Control is performed to prevent transmission of a large torque.
[0064]
When four wheels are indicated on the instrument panel and a wheel to which a different diameter tire is attached is detected, the tire indication lamp corresponding to the wheel is turned on and the different diameter tire is attached. You may make it alert | report to a driver | operator. In addition, it is possible to notify the driver of insufficient air pressure by turning on the tire display lamp.
[0065]
【The invention's effect】
As described above, according to the present invention, since the different-diameter tire can be specified even if the different-diameter tire is not only one wheel but is attached to two wheels, the different-diameter tire can be specified. The presence / absence of tire wearing can be detected more accurately.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a power transmission system of a four-wheel drive vehicle. FIG. 2 is a schematic configuration diagram of a signal rotor and a wheel speed sensor. FIG. 3 is a flowchart showing a different diameter tire detection routine (part 1).
FIG. 4 is a flowchart showing a different diameter tire detection routine (part 2).
[Explanation of symbols]
10L Front left wheel 10R Front right wheel 11L Rear left wheel 11R Rear right wheel 27L, 27R, 28L, 28R Wheel speed sensor (wheel speed detection means)
AFRVH Front / Rear Wheel Speed Ratio ALRVH Left / Right Wheel Speed Ratio F_LRVw, FR_LVV, FR_RVw, R_LRVw Average Wheel Speed F_RVw, F_LVw, R_RVw, R_LVw Wheel Speed F_LRVH Front Left / Right Wheel Speed Ratio R_LRVH Rear Left / Right Wheel Speed Ratio TIME VHLo Wheel speed ratio lower value

Claims (5)

Wheel speed detecting means provided on each wheel of the vehicle for detecting the wheel speed of each wheel;
Based on the wheel speed detected by each wheel speed detecting means, the left and right wheel speed ratio between the average wheel speed of the front and rear left wheels and the average wheel speed of the front and rear right wheels and the average value of the wheel speeds of the front left and right wheels And a wheel speed ratio calculating means for calculating a front and rear wheel speed ratio based on an average value of wheel speeds of the rear left and right wheels,
When one of the two wheel speed ratios is within a preset wheel speed ratio region when different diameter tires are mounted and the other wheel speed ratio indicates 1 or a value close to 1, the one wheel speed Different diameter tire detection means for identifying two wheels on which different diameter tires are mounted based on the wheel speed for calculating the ratio;
A different diameter tire detection apparatus comprising: Wheel speed detecting means provided on each wheel of the vehicle for detecting the wheel speed of each wheel;
Based on the wheel speed detected by each wheel speed detecting means, the front left / right wheel speed ratio of the front left / right wheels, the rear left / right wheel speed ratio of the rear left / right wheels, the average wheel speed of the front left / right wheels, and the rear left / right wheels Wheel speed ratio calculating means for calculating a front and rear wheel speed ratio based on an average value of wheel speeds of
Both the front left / right wheel speed ratio and the rear left / right wheel speed ratio are within a preset wheel speed ratio region when different diameter tires are mounted, and the front / rear wheel speed ratio is 1 or a value close to 1. Different diameter tire detection that identifies two wheels, a front left rear right wheel or a front right rear left wheel on which a different diameter tire is mounted based on the front left / right wheel speed ratio and the rear left / right wheel speed ratio Means,
A different diameter tire detection apparatus comprising: Above the different-diameter tire detecting means, when specifying the wheel which the different-diameter tire is mounted, according to claim 1 or 2, wherein determining that the different-diameter tires mounted and where this state continues for a set time Different diameter tire detection device. In the different-diameter tire detecting means checks whether or not the different-diameter tire determination permission condition can be detected correctly mounting the different-diameter tire based on the operating state of the vehicle, when the different-diameter tire determination permission condition is not satisfied the different-diameter tire detecting apparatus according to any one of claim 1 3, characterized in that to cancel the different-diameter tire detection processing. In the different-diameter tire detection means, after determining that different diameter tires, examine the release condition of the different-diameter tire mounted state, when said release condition is satisfied to cancel the judgment result of the different-diameter tires The different-diameter tire detection device according to claim 3 or 4 , characterized by the above.

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