CN106114080A - Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number and method - Google Patents

Abstract

The invention discloses a kind of tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number, including: vehicle wheel rotation umber of pulse monitoring means, it is used for producing, receiving each vehicle wheel rotation umber of pulse information；Wheel pulse number computing judgement unit, for according to obtain each wheel pulse number information set up wheel standards umber of pulse as benchmark and by each take turns actual measurement umber of pulse correction after compare with respective calibration pulse number, differentiate that tire pressure is the most abnormal, and send differentiation object information to tire pressure display unit.With low cost, can differentiate that two-wheeled tire pressure is the most too low and the most too low situation of three-wheel tire pressure, four-wheel deficency situation the most in various degree can be accurately identified again；The vehicle that front and back wheel standard tire pressure is identical can be differentiated, the vehicle that front and back wheel standard tire pressure is different can be accurately identified again.

Description

Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number and method

Technical field

The present invention relates to automobile tire pressure monitoring warning system technical field, more particularly to one based on wheel pulse Number

The tire pressure monitoring early warning system of absolute relative method and method.

Background technology

Mass data shows: in use, tire monthly leak rate reaches 1%～4% to automobile, and tire can be caused long Phase is run with the situation less than normal tire pressure, makes squeegee action increase, and intensity reduces, accident of eventually blowing out, and causes tight The loss of personal property of weight；Meanwhile, tire pressure reduce, also can oversize tyre resistance to rolling, increase Fuel consumption.Therefore, right Air pressure of automobile tire is monitored in real time, finds abnormal tyre pressure and alarm, contributes to driver and maintain tire pressure to be in standard shape State, while being effectively improved vehicle driving safety, it is achieved energy-saving and cost-reducing purpose.

In prior art, tire pressure monitoring system mainly has direct-type and a big class of indirect type two: direct-type be in tire or Installing pressure transducer on valve cock additional and directly measure tire pressure, surveyed tire pressure data are wirelessly sent to receptor, Be then displayed on monitor, or shown by the form such as sound, light, have response fast, highly sensitive, tire pressure can be shown in real time Etc. feature, but mounting process is complicated, and cost is high, and sensor by vibrations, high temperature, high pressure and centrifugal action and is wirelessly transferred Data etc. affect, and functional reliability reduces, additionally still without the scheme of a preferable process waste battery, for this indirect type TPMS research receives great attention.Indirect type TPMS, by obtaining wheel speed information, is differentiated through special algorithm computing by ECU Whether tire pressure normal, do not increase because of it part, constitute simple and direct, power consumption less, with low cost, be easy to the features such as popularization, attracted each World-famous motor corporation endeavours its research.

Indirect type TPMS technology has developed into wheel speed diagnostic method, frequency spectrum diagnostic method, three kinds of methods of umber of pulse diagnostic method, its Middle wheel speed diagnostic method is only capable of identifying single-wheel tire pressure deficency situation and not can designate that deficency tire location, frequency spectrum diagnostic method by road conditions and The impact of the factor such as vehicle self-technique situation is relatively big, and be only capable of speed higher than 30km/h and less than 100km/h between work, super Going out this scope rate of false alarm higher, therefore this technology still fails to reach popularization and application；Pulse diagnostic method be by each wheel pulse number with The meansigma methods of this car wheel pulse number compares, by differentiating whether whether its difference differentiate tire pressure more than corresponding threshold value Abnormal, although the method can recognize that the position of abnormal tyre pressure tire, just can normally work when speed reaches 10Km/h, even if Speed reaches 120km/h also can keep working properly, but can not identify that under ladder tire pressure condition tire pressure is the most abnormal, can not Identify that 4 take turns deficency situation the most in various degree, the present invention is directed to these problems, use each absolute relative method of wheel pulse number perfect Umber of pulse diagnostic method indirect type TPMS technology.

Summary of the invention

The technological deficiency existed for TPMS wheel pulse number capacitive equipments, the purpose of the present invention is to propose to a kind of base In tire pressure monitoring early warning system and the method for the absolute relative method of wheel pulse number, can accurately know keeping wheel pulse diagnostic method While not going out this feature of position of abnormal tire pressure wheel, can differentiate that two-wheeled tire pressure is the most too low and three-wheel tire pressure mistake simultaneously Low situation, can accurately identify again four-wheel deficency situation the most in various degree；The car that front and back wheel standard tire pressure is identical can be differentiated , the vehicle that front and back wheel standard tire pressure is different can be accurately identified again.

The technical scheme is that

A kind of tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number, it is characterised in that including:

One vehicle wheel rotation umber of pulse monitoring means, is used for producing, receiving each vehicle wheel rotation umber of pulse information；

One wheel pulse number computing judgement unit, for setting up wheel standards arteries and veins according to each wheel pulse number information obtained Strokes per minute as benchmark and by each take turns actual measurement umber of pulse correction after compare with respective calibration pulse number, it determines whether tire pressure Abnormal, and send differentiation object information to tire pressure display unit.

Preferably, described wheel pulse number computing judgement unit includes:

Calibration pulse base standard sets up unit, and the calibration pulse base setting up each wheel is accurate, for the actual measurement arteries and veins of each wheel Strokes per minute compares with respective calibration pulse number；

Wheel pulse number amending unit, is modified each wheel actual measurement umber of pulse, makes corresponding to revised umber of pulse Wheel rolling distance be equal or approximately equal with the wheel rolling distance corresponding to calibration pulse number；

Tire pressure condition discrimination alarm unit, by the difference of relatively each wheel corrected impulse number with calibration pulse number, it determines Tire pressure Status Level and the position of abnormal tyre pressure wheel, send wheel pulse number to tire pressure display unit and differentiate result letter Breath.

Preferably, described wheel pulse number computing judgement unit also includes self study unit, for working as vehicle wheel roll radius During sudden change, carry out self study, update each wheel standards umber of pulse benchmark.Vehicle wheel roll radius sudden change includes tire rotation, tire Updating, tire maintenance QI invigorating and four-wheel aligner etc., in this learning process, vehicle is steady with middling speed on the straight road of good road conditions Traveling is carried out, insensitive to speed size requirements.

Preferably, when Vehicular turn, described wheel pulse number amending unit is to axle wheel pulse number phase when turning to Revise mutually, revise the product that afterpulse number is actual measurement umber of pulse and correction factor.

Preferably, after receiving vehicle brake signal or wheel slip signal, reject in braking procedure or car Each wheel pulse number of statistics in slipping.

Preferably, described tire pressure display unit is the instrumental panel or separate display screens coupled with vehicle-mounted CAN system, The position of display abnormal tyre pressure wheel and tire pressure height low degree.

The invention also discloses a kind of tire pressure monitoring method for early warning based on the absolute relative method of wheel pulse number, its feature exists In, comprise the following steps:

S01: travel certain distance with certain speed and to record the umber of pulse of vehicle wheel rotation be this wheel at standard tire pressure Calibration pulse number

S02: seek meansigma methods N of four wheel standards umber of pulses respectively₀With each wheel standards umber of pulseRatioCar Each monitoring cycle of wheel umber of pulse surveys umber of pulse N with each wheel_iWithProduct in minima reach calibration pulse number Meansigma methods N₀Till；

S03: seek the difference Δ N of each wheel actual measurement umber of pulse and corresponding calibration pulse number_iAnd to this difference DELTA N_iArrange by size Sequence, is modified, to wheel pulse number correction value each wheel actual measurement umber of pulseFit to about Δ N_iFunction f (Δ N_i), the wheel rolling distance corresponding to revised umber of pulse and the wheel rolling corresponding to calibration pulse number apart from equal or Approximately equal；

S04: the difference that revised each wheel pulse number is definitely compared with respective calibration pulse numberWith corresponding High tire pressure threshold value Δ_HWith low tire pressure threshold value Δ_LCompare, ifAndThen it is judged to this tire Press through height；IfAndThen judge that this wheel tyre pressure is too low.

Preferably, in described step S01, when vehicle wheel roll radius suddenlys change, carry out self study, update each wheel standards arteries and veins Strokes per minute benchmark.

Preferably, in described step S02, function f (Δ N_i) by approximating solution by iterative method or using fitting process and change Jointly solve for method.

Preferably, tire pressure step display is also included:

Use green LED lamppost represent tire pressure in 115%～85% standard tire pressure scope, green when tire pressure is standard tire pressure Coloured light post is the highest, and column of green light shortens expression tire pressure and changes, but also at normal operating range；

When 85% that tire pressure is standard tire pressure, column of green light shortens to zero and becomes column of red light, the highest expression of column of red light Leaking gas the most serious, when tire pressure drops to the 60% of standard tire pressure, while column of red light flashes, buzzer is also reported to the police ring；

Use orange-yellow lamppost to represent the degree that tire pressure is too high, when tire pressure is increased to the 115% of standard tire pressure, become orange Yellow light beam, when tire pressure is increased to the 140% of standard tire pressure, while orange-yellow light beam flashes, buzzer is also reported to the police ring Ring.

Wheel pulse number correction valueBoth vehicle wheel roll radius can be caused to change cartwheel roll with the change of modifying factor speed The impact of dynamic distance, it is also possible to the change of modifying factor tire pressure causes the vehicle rolling radius change impact on wheel rolling distance, also It can be the impact of the wheel rolling distance change caused because of other factors.

Compared with prior art, the invention have the advantage that

1, the wheel pulse number absolute relative method monitoring tire pressure technology of the present invention, can not only be not normal to single wheel tyre pressure It is monitored early warning, it is also possible to take turns 2,3 take turns and 4 take turns that tire pressure is simultaneously abnormal is monitored early warning, additionally it is possible to having ladder Four wheels of tire pressure are monitored early warning.

2, the present invention can not only be monitored early warning to the vehicle that front and back wheel standard tire pressure is identical, moreover it is possible to front and back wheel The different vehicle of standard tire pressure is monitored early warning.

3, abnormal conditions various to wheel tyre pressure early warning be can not only be monitored, anomalous wheel position, Er Qieben identified Technological invention make for various tire technology situations carry out self study process become the simplest and the most direct feasible.

4, rapid air leakage of tyre can be automatically formed positive feedback, shorten tire pressure and differentiate the time, effectively reduce False Rate and Misdetection rate, this technology also has the features such as low cost, reliability is high, installation maintenance is simple and convenient simultaneously.

Accompanying drawing explanation

Below in conjunction with the accompanying drawings and embodiment the invention will be further described:

Fig. 1 is the structured flowchart of tire pressure monitoring early warning system of the present invention；

Fig. 2 is the flow chart of tire pressure monitoring method for early warning of the present invention.

Detailed description of the invention

For making the object, technical solutions and advantages of the present invention of greater clarity, below in conjunction with detailed description of the invention and join According to accompanying drawing, the present invention is described in more detail.It should be understood that these describe the most exemplary, and it is not intended to limit this Bright scope.Additionally, in the following description, eliminate the description to known features and technology, to avoid unnecessarily obscuring this The concept of invention.

Embodiment:

Tire pressure monitoring early warning system of the present invention includes the wheel speed sensor being arranged on four wheels of vehicle, receiving area The wheel pulse number of the pulse signal of reason wheel speed sensor output receives processing unit, and pulse signal is stored in wheel In umber of pulse computing judgement unit, computing judgement unit is provided that a certain amount of information storage function and can carry out respective rule Algorithm computing, to differentiate that tire pressure is the most abnormal, and will differentiate that object information exports tire pressure display unit or the letter specified In breath receptor, such as: CAN system or display screen etc..

Certain vehicle vehicle is with standard tire pressure P₀With a certain stabilizing speed V₀Travel certain distance S₀, record each wheel standards arteries and veins Strokes per minuteBeing respectively as follows: the near front wheel isOff-front wheel isLeft rear wheel isOff hind wheel isFour wheel standards umber of pulses Meansigma methods be N₀, N₀With each wheel standards umber of pulseRatio be

This vehicle is in a certain monitoring time period t, with tire pressure P_i, vehicle velocity V travels, wheel is surveyed umber of pulse N_iWithTake advantage of Long-pending referred to as umber of pulse count value, the minima counted to each wheel pulse counting number value from beginning registration of vehicle pulse reaches standard Meansigma methods N of umber of pulse₀Time till, record each wheel actual measurement umber of pulseBeing respectively as follows: the near front wheel isOff-front wheel is Left rear wheel isOff hind wheel isN₀The revolution of the wheel rolling that individual wheel pulse number is corresponding should be not less than 60 turns and be not higher than 120 turns, make the monitoring cycle both will not occur that rate of false alarm was too high because the monitoring cycle is the shortest, also will not drop because the monitoring cycle is oversize Low tire pressure monitoring sensitivity.

Calculating each wheel actual measurement umber of pulse with the difference of corresponding calibration pulse number is:And it is rightPress Sort from small to large, be respectively as follows:Corresponding wheel standards umber of pulse is respectively as follows: Corresponding each wheel actual measurement umber of pulse is respectively as follows:Corresponding wheel is respectively as follows: No. 1 wheel, No. 2 Wheel, No. 3 wheels, No. 4 wheels.

Monitor the time period at t, order: No. 1 wheel is rotatingAfter individual pulse, also need to be rotated further byIndividual pulse, it is rolled Dynamic distance could be with distance S of this wheel rolling under standard state₀Equal；For the correction for No. 1 wheel actual measurement umber of pulse Value, revised umber of pulse isWith corresponding calibration pulse numberDifference DELTA₁For:

Due toIt is worth less, now it is believed that No. i-th wheel is rotatingAfter individual pulse, it is rotated further byIndividual pulse, its institute Distance S of distance also No. i-th wheel rolling lower with standard state rolled₀Approximately equal；

Solve the method example one of wheel pulse number correction value:

Owing to wheel rolling is apart from equal, according to the relation of speed Yu vehicle wheel roll radius: r=k_v(v-v₀)+r₀And tire pressure Relation with vehicle wheel roll radius: r=k_p(p-p₀)+r₀, and the relation of radius of wheel r, umber of pulse N and rolling distance S: r= ZS/ (2 π N), can derive No. 1 and take turns revised umber of pulse N₁With corresponding calibration pulse numberDifference DELTA₁For:

${\mathrm{\Δ}}_1=N_1-N_1^0=k_0{k}_v(v_0-v)+k_0{k}_p(p_0-p)={\mathrm{\ΔN}}_{v1}^t+{\mathrm{\ΔN}}_{p1}^t---\left(1\right)$

In formula (1): k_vFor speed and radius of wheel variation coefficient, k_pFor tire pressure and radius of wheel variation coefficient；k₀=N₀/ (2r₀), wheel rolling radius in normal conditions is r₀, rolling distance is S₀Time corresponding average pulse number be N₀；

In formula (1): No. 1 wheel causes the variable quantity of umber of pulse the t monitoring time period due to speed changeBy The variable quantity of umber of pulse is caused in tire pressure changeIt is respectively as follows:

${\mathrm{\ΔN}}_{v1}^t=k_0{k}_v(v_0-v)---\left(2\right)$

${\mathrm{\ΔN}}_{p1}^t=k_0{k}_p(p_0-p)---\left(3\right)$

Obtained by (1) formula:

${\mathrm{\ΔN}}_{p1}^t=N_1-N_1^0-{\mathrm{\ΔN}}_{v1}^t=N_1^t+{\mathrm{\ΔN}}_1^0-N_1^0-{\mathrm{\ΔN}}_{v1}^t={\mathrm{\ΔN}}_1^t+{\mathrm{\ΔN}}_1^0-{\mathrm{\ΔN}}_{v1}^t---\left(4\right)$

According to (4) formula, can derive to any wheel, No. 2 wheels are had:

${\mathrm{\ΔN}}_{p2}^t=N_2^t+{\mathrm{\ΔN}}_1^0-N_2^0-{\mathrm{\ΔN}}_{v2}^t={\mathrm{\ΔN}}_2^t+{\mathrm{\ΔN}}_1^0-{\mathrm{\ΔN}}_{v2}^t---\left(5\right)$

Because each wheel average linear velocity on same car of same time period can be approximately considered identical, then vehicle is monitored at t The umber of pulse variation meansigma methods that time period each wheel produces because of speed changeFor: Due toThen have:Might as well make:Wherein:For when monitoring for the t Between section Δ N_p1With Δ N_p2Variation relation coefficient, andSubstituted into (4) formula and (5) formula simultaneous solution, can be obtained:

${\mathrm{\ΔN}}_1^0={\mathrm{\ΔN}}_v^t+(\frac{k_1^t}{1-k_1^t}{\mathrm{\ΔN}}_2^t-\frac{1}{1-k_1^t}{\mathrm{\ΔN}}_1^t)---\left(6\right)$

In like manner, can obtain:

${\mathrm{\ΔN}}_2^0={\mathrm{\ΔN}}_v^t+(\frac{k_2^t}{1-k_2^t}{\mathrm{\ΔN}}_3^t-\frac{1}{1-k_2^t}{\mathrm{\ΔN}}_2^t)---\left(7\right)$

${\mathrm{\ΔN}}_3^0={\mathrm{\ΔN}}_v^t+(\frac{k_3^t}{1-k_3^t}{\mathrm{\ΔN}}_4^t-\frac{1}{1-k_3^t}{\mathrm{\ΔN}}_3^t)---\left(8\right)$

In above-mentioned (7) (8) formula,It is respectively the correction value for No. 2 and No. 3 wheel actual measurement umber of pulses, it may be assumed that the 2nd Number wheel is rotatingAfter individual pulse, also need to be rotated further byIndividual pulse, its distance rolled could No. 2 cars lower with standard state Distance s that wheel rolls₀Equal；No. 3 wheel is rotatingAfter individual pulse, also need to be rotated further byIndividual pulse, No. 3 wheels are rolled Distance could be with distance s of this wheel rolling under standard state₀Equal；And have And

Can obtain from above-mentioned analysis:That is: t monitors Time period each wheel is rotatingAfter individual pulse, also need to be rotated further by the N number of pulse of Δ, distance that it is rolled could and standard state Under distance s of each wheel rolling₀Equal；Δ N is the common correction value for each wheel actual measurement umber of pulse.That is:

$N_1=N_1^t+\mathrm{\Δ}N---\left(9\right)$

$N_2=N_2^t+\mathrm{\Δ}N---\left(10\right)$

$N_3=N_3^t+\mathrm{\Δ}N---\left(11\right)$

$N_4=N_4^t+\mathrm{\Δ}N---\left(12\right)$

Again due to:And No. 4 wheel is the fastest wheel that leaks gas, it could even be possible to be Prick the wheel of tire,Numerical stability is in descending order:Therefore take three's factor of influence to divide Not Wei α=0.6, β=0.3, γ=0.1, therefore have

$\mathrm{\Δ}N=0.6{\mathrm{\ΔN}}_1^0+0.3{\mathrm{\ΔN}}_2^0+0.1{\mathrm{\ΔN}}_3^0---\left(13\right)$

By (9) formula substitution (4) Shi Ke get:

${\mathrm{\ΔN}}_{p1}^t=N_1-N_1^0-{\mathrm{\ΔN}}_{v1}^t=N_1^t+\mathrm{\Δ}N-N_1^0-{\mathrm{\ΔN}}_{v1}^t={\mathrm{\ΔN}}_1^t+\mathrm{\Δ}N-{\mathrm{\ΔN}}_v^t---\left(14\right)$

In like manner, can be derived to other each wheels by (14) formula in conjunction with (10) (11) (12), therefore have:

${\mathrm{\ΔN}}_{p2}^t={\mathrm{\ΔN}}_2^t+\mathrm{\Δ}N-{\mathrm{\ΔN}}_v---\left(15\right)$

${\mathrm{\ΔN}}_{p3}^t={\mathrm{\ΔN}}_3^t+\mathrm{\Δ}N-{\mathrm{\ΔN}}_v---\left(16\right)$

${\mathrm{\ΔN}}_{p4}^t={\mathrm{\ΔN}}_4^t+\mathrm{\Δ}N-{\mathrm{\ΔN}}_v---\left(17\right)$

By (6) (7) (8) formula and (13) (14) formula simultaneous solution,

Can obtain:

${\mathrm{\ΔN}}_{p1}^t={\mathrm{\ΔN}}_1^t+\[0.6\frac{k_1^t{\mathrm{\ΔN}}_2^t-{\mathrm{\ΔN}}_1^t}{1-k_1^t}+0.3\frac{k_2^t{\mathrm{\ΔN}}_3^t-{\mathrm{\ΔN}}_2^t}{1-k_2^t}+0.1\frac{k_3^t{\mathrm{\ΔN}}_4^t-{\mathrm{\ΔN}}_3^t}{1-k_3^t}\]---\left(18\right)$

In like manner can derive:

${\mathrm{\ΔN}}_{p2}^t={\mathrm{\ΔN}}_2^t+\[0.6\frac{k_1^t{\mathrm{\ΔN}}_2^t-{\mathrm{\ΔN}}_1^t}{1-k_1^t}+0.3\frac{k_2^t{\mathrm{\ΔN}}_3^t-{\mathrm{\ΔN}}_2^t}{1-k_2^t}+0.1\frac{k_3^t{\mathrm{\ΔN}}_4^t-{\mathrm{\ΔN}}_3^t}{1-k_3^t}\]---\left(19\right)$

${\mathrm{\ΔN}}_{p3}^t={\mathrm{\ΔN}}_3^t+\[0.6\frac{k_1^t{\mathrm{\ΔN}}_2^t-{\mathrm{\ΔN}}_1^t}{1-k_1^t}+0.3\frac{k_2^t{\mathrm{\ΔN}}_3^t-{\mathrm{\ΔN}}_2^t}{1-k_2^t}+0.1\frac{k_3^t{\mathrm{\ΔN}}_4^t-{\mathrm{\ΔN}}_3^t}{1-k_3^t}\]---\left(20\right)$

${\mathrm{\ΔN}}_{p4}^t={\mathrm{\ΔN}}_4^t+\[0.6\frac{k_1^t{\mathrm{\ΔN}}_2^t-{\mathrm{\ΔN}}_1^t}{1-k_1^t}+0.3\frac{k_2^t{\mathrm{\ΔN}}_3^t-{\mathrm{\ΔN}}_2^t}{1-k_2^t}+0.1\frac{k_3^t{\mathrm{\ΔN}}_4^t-{\mathrm{\ΔN}}_3^t}{1-k_3^t}\]---\left(21\right)$

WhenBy sequence from small to large identical with previous monitoring period of time time, in (18) (19) (20) (21) formula,And as t=1, WhenTime,

WhenBy sequence from small to large different from previous monitoring period of time time, in (18) (19) (20) (21) formula,

When radius of wheel sudden change meets self study condition, system carries out self study, re-establishes new each wheel standards Umber of pulse benchmark；After each self study of system, monitoring period of time ordinal number t restarts counting；

Therefore, according to measured each wheel pulse number, obtain revised each wheel pulse number and respective calibration pulse The difference that number definitely comparesThe umber of pulse changing value that the most each wheel pulse number produces because of tire pressure change, with corresponding high tire Pressure gate limit Δ_HWith low tire pressure threshold value Δ_LCompare, ifAndThen it is judged to that this tire presses through High；IfAndThen judge that this wheel tyre pressure is too low.

When Vehicular turn, according to steering wheel angle size and rotation direction, first the umber of pulse of corresponding wheel is repaiied Just so that it is can compare with wheel pulse number during straight-line travelling；

When turning to, axle wheel pulse number is mutually revised, and revises afterpulse number for actual measurement umber of pulse N and correction factor k Product；Each wheel pulse number correction factor is:

$k_{FL}=\frac{N_{RL}+N_{RR}}{2N_{RL}};k_{FR}=\frac{N_{RL}+N_{RR}}{2N_{RR}};$

$k_{RL}=\frac{N_{FL}+N_{FR}}{2N_{FL}};k_{RR}=\frac{N_{FL}+N_{FR}}{2N_{FR}}---\left(22\right)$

In (22) formula, k_FLFor front revolver correction factor, N_FLUmber of pulse, k is surveyed for front revolver_FRFor front right wheel correction system Number, N_FRUmber of pulse, k is surveyed for front right wheel_RLFor rear revolver correction factor, N_RLUmber of pulse, k is surveyed for rear revolver_RRRepair for rear right wheel Positive coefficient, N_RRUmber of pulse is surveyed for rear right wheel.

When car braking, after receiving brake signal, each car that native system will be added up in automatic rejection braking procedure Wheel umber of pulse, in order to avoid erroneous judgement tire pressure.

When vehicle generation sliding, after receiving wheel slip signal, native system is by this section of driving process of automatic rejection Middle added up each wheel pulse number, in order to avoid erroneous judgement tire pressure.

Solve the example two of method of actual measurement wheel pulse number correction value:

Employing fitting process solves；(6) (7) (8) are substituted into (13) formula, in the common correction value of each wheel pulse number of gained In Δ N expression formula, it is believed thatThere is the coefficient of different constant, therefore, can make:

$\mathrm{\Δ}N={\mathrm{\ΔN}}_v^t+{\mathrm{\α}}_1{\mathrm{\ΔN}}_1^t+{\mathrm{\α}}_2{\mathrm{\ΔN}}_2^t+{\mathrm{\α}}_3{\mathrm{\ΔN}}_3^t+{\mathrm{\α}}_4{\mathrm{\ΔN}}_4^t+{\mathrm{\α}}_0---\left(23\right)$

In (23) formula, α₀, α₁, α₂, α₃, α₄For constant, select 5 kinds of different facts for (23) formula, take an entrance examination mutually Test, corresponding coefficient can be obtained according to test data, simulate each common correction value of wheel pulse number.

Solve the example three of method of actual measurement wheel pulse number correction value:

Use fitting process to solve (6) (7) (8) formula the most respectively, obtainAfter, then substitute into (13) formula Obtain the common correction value Δ N of each wheel pulse number.

UtilizeWhen solving the common correction value Δ N of each wheel pulse number, available In any two value be fitted solving Δ N.

Tire pressure discriminant information display example four:

Tire pressure differentiating, object information couples with vehicle-mounted CAN system show on instrumental panel, can be shown by LCD screen The position of abnormal tyre pressure wheel, it is possible to whether normal by single display lamp display tire pressure, and pass through voice prompt alarm；

Tire pressure discriminant information display example five:

Tire pressure is differentiated, and object information is connected with independent display screen, shows the position of abnormal tyre pressure wheel on a display screen Put, and the height of the light beam lighted by ELD on screen shows the degree that tire pressure is high or low.

Wheel tyre pressure monitoring and pre-alarming method example six:

Fig. 2 is wheel tyre pressure monitoring and pre-alarming method program circuit, wherein, sets up or updates each wheel pulse number benchmark For one of subprogram in this program, it is to set up or update each wheel standards umber of pulse for tire technology changed condition, with As for the purpose of the benchmark that each wheel pulse number definitely compares.The change of wheel technology status includes tire rotation, and tire is more Newly, tire maintenance QI invigorating and four-wheel aligner etc. can make the situation that vehicle wheel roll radius suddenlys change,

Calculating umber of pulse correction value is the another subprogram in this program, is to utilize (13) formula or (23) formula or other calculations Method, calculates wheel pulse number correction value, to realize the correction to each wheel actual measurement umber of pulse, makes the revised pulse of each wheel Number can compare with each wheel standards umber of pulse.

Calculating each wheel because of the umber of pulse changing value of tire pressure change generation is the another subprogram in this program, is basis (18) after formula etc. reject non-tire pressure influence factor, the difference that each wheel pulse number definitely compares with respective calibration pulse number

Differentiate that each wheel tyre pressure state is the another subprogram in this program, measure the cycle according to continuous 3 or 5 Umber of pulse computingCross high threshold with tire pressure or cross threshold ones result of the comparison with tire pressure, by small sample diagnostic method or Differentiate, by the size of its meansigma methods, the degree that tire pressure is too high or too low, and determine the need for carrying out abnormal tyre pressure warning.

Show that each wheel tyre pressure information is the another subprogram in this program, represent that tire pressure is 115% with green LED lamppost ～85% standard tire pressure scope, when tire pressure is standard tire pressure, column of green light is the highest, and column of green light shortens and represents that tire pressure changes, But also at normal operating range；When 85% that tire pressure is standard tire pressure, column of green light shortens to zero and becomes column of red light, red Light beam the highest represent gas leakage the most serious, when 60% that tire pressure is standard tire pressure or less than 60% time column of red light the highest, work as tire pressure When dropping to the 75% of standard tire pressure, column of red light flicker and light beam height are the half of height overall, when tire pressure drops to standard tire Pressure 60% time, while column of red light flashes, buzzer is also reported to the police ring；Orange-yellow lamppost represents the degree that tire pressure is too high, When 140% that tire pressure is standard tire pressure or higher than 140% time, orange-yellow lamppost is the highest, when tire pressure is increased to standard tire pressure When 125%, the flicker of orange-yellow light beam and light beam height are the half of height overall, when tire pressure is increased to the 140% of standard tire pressure, While the flicker of orange-yellow light beam, buzzer is also reported to the police ring.

It should be appreciated that the above-mentioned detailed description of the invention of the present invention is used only for exemplary illustration or explains the present invention's Principle, and be not construed as limiting the invention.Therefore, that is done in the case of without departing from the spirit and scope of the present invention is any Amendment, equivalent, improvement etc., should be included within the scope of the present invention.Additionally, claims purport of the present invention Whole within containing the equivalents falling into scope and border or this scope and border change and repair Change example.

Claims (10)

1. a tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number, it is characterised in that including:

One vehicle wheel rotation umber of pulse monitoring means, is used for producing, receiving each vehicle wheel rotation umber of pulse information；

One wheel pulse number computing judgement unit, for setting up wheel standards umber of pulse according to each wheel pulse number information obtained As benchmark and by each take turns actual measurement umber of pulse correction after compare with respective calibration pulse number, it determines tire pressure is the most different Often, and to tire pressure display unit send and differentiate object information.

Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number the most according to claim 1, its feature exists In, described wheel pulse number computing judgement unit includes:

Calibration pulse base standard sets up unit, and the calibration pulse base setting up each wheel is accurate, for the actual measurement umber of pulse of each wheel Compare with respective calibration pulse number；

Wheel pulse number amending unit, is modified each wheel actual measurement umber of pulse, makes the car corresponding to revised umber of pulse Wheel rolling distance is equal or approximately equal with the wheel rolling distance corresponding to calibration pulse number；

Tire pressure condition discrimination alarm unit, by the difference of relatively each wheel corrected impulse number with calibration pulse number, it determines tire pressure Status Level and the position of abnormal tyre pressure wheel, send wheel pulse number to tire pressure display unit and differentiate object information.

Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number the most according to claim 2, its feature exists In, described wheel pulse number computing judgement unit also includes self study unit, for when vehicle wheel roll radius suddenlys change, carries out certainly Study, updates each wheel standards umber of pulse benchmark.

Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number the most according to claim 2, its feature exists In, when Vehicular turn, axle wheel pulse number when turning to mutually is revised by described wheel pulse number amending unit, revises Afterpulse number is the product of actual measurement umber of pulse and correction factor.

Tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number the most according to claim 2, its feature exists In, after receiving vehicle brake signal or wheel slip signal, reject in braking procedure or during vehicle slip Each wheel pulse number of statistics.

6. according to the tire pressure monitoring early warning system based on the absolute relative method of wheel pulse number described in any one of claim 1-5, It is characterized in that, described tire pressure display unit is the instrumental panel or separate display screens coupled with vehicle-mounted CAN system, display The position of abnormal tyre pressure wheel and tire pressure height low degree.

7. a tire pressure monitoring method for early warning based on the absolute relative method of wheel pulse number, it is characterised in that comprise the following steps:

S01: travel certain distance with certain speed at standard tire pressure and record the standard that umber of pulse is this wheel of vehicle wheel rotation Umber of pulse

S02: seek meansigma methods N of four wheel standards umber of pulses respectively₀With each wheel standards umber of pulseRatioWheel arteries and veins Each monitoring cycle of strokes per minute surveys umber of pulse N with each wheel_iWithProduct in minima reach the flat of calibration pulse number Average N₀Till；

S03: seek the difference Δ N of each wheel actual measurement umber of pulse and corresponding calibration pulse number_iAnd to this difference DELTA N_iSort by size, Each wheel actual measurement umber of pulse is modified, to wheel pulse number correction valueFit to about Δ N_iFunction f (Δ N_i), Wheel rolling distance corresponding to revised umber of pulse and the wheel rolling corresponding to calibration pulse number are apart from equal or approximation Equal；

S04: the difference that revised each wheel pulse number is definitely compared with respective calibration pulse numberWith corresponding high tire Pressure gate limit Δ_HWith low tire pressure threshold value Δ_LCompare, ifAndThen it is judged to that this tire presses through High；IfAndThen judge that this wheel tyre pressure is too low.

Tire pressure monitoring method for early warning based on the absolute relative method of wheel pulse number the most according to claim 7, its feature exists In, in described step S01, when vehicle wheel roll radius suddenlys change, carry out self study, update each wheel standards umber of pulse benchmark.

Tire pressure monitoring method for early warning based on the absolute relative method of wheel pulse number the most according to claim 7, its feature exists In, in described step S02, function f (Δ N_i) jointly solved by approximation solution by iterative method or employing fitting process and iterative method.

Tire pressure monitoring method for early warning based on the absolute relative method of wheel pulse number the most according to claim 7, its feature exists In, also include tire pressure step display:

Green LED lamppost is used to represent that tire pressure is in 115%～85% standard tire pressure scope, the green light when tire pressure is standard tire pressure Post is the highest, and column of green light shortens expression tire pressure and changes, but also at normal operating range；

When 85% that tire pressure is standard tire pressure, column of green light shortens to zero and becomes column of red light, and column of red light is the highest represents gas leakage The most serious, when tire pressure drops to the 60% of standard tire pressure, while column of red light flashes, buzzer is also reported to the police ring；

Use orange-yellow lamppost to represent the degree that tire pressure is too high, when tire pressure is increased to the 115% of standard tire pressure, become orange-yellow Light beam, when tire pressure is increased to the 140% of standard tire pressure, while orange-yellow light beam flashes, buzzer is also reported to the police ring.