阅读说明：本技术 评估特别是用于轨道车辆的路轨的污染和清洁的方法 (Method for assessing the contamination and cleaning of rails, in particular for rail vehicles ) 是由 马特奥·弗雷亚 卢卡·因贝特 于 2018-06-12 设计创作，主要内容包括：描述了一种用于评估路轨的污染的方法,所述路轨特别是用于轨道车辆,包括以下步骤：在第一受控车轴(A1)的车轮(W<Sub>1</Sub>)和路轨之间施加小于第一阈值(t<Sub>1</Sub>)的第一滑行值(δ<Sub>1</Sub>)；第一受控车轴(A<Sub>1</Sub>)为轨道车辆的前车轴；在第二受控车轴(A<Sub>2</Sub>)的车轮和路轨之间施加大于第二阈值(t<Sub>2</Sub>)的第二滑行值(δ<Sub>2</Sub>)；第二车轴(A<Sub>2</Sub>)为跟随第一车轴(A<Sub>1</Sub>)的车轴,并且第二阈值(t<Sub>2</Sub>)大于第一阈值(t<Sub>1</Sub>)；基于第一车轴(A<Sub>1</Sub>)的车轮与路轨之间的第一附着力值(μ<Sub>1</Sub>)和第二车轴(A<Sub>2</Sub>)的车轮与路轨之间的第二附着力值(μ<Sub>2</Sub>),来确定属于多个受控车轴(A<Sub>n</Sub>)的车轮(W)与路轨之间的附着力曲线的趋势。(A method is described for assessing the contamination of a rail, in particular for a rail vehicle, comprising the following steps: at the wheels (W) of the first controlled axle (A1) 1 ) And less than a first threshold (t) applied between the rails 1 ) First slip value (δ) 1 ) (ii) a First controlled axle (A) 1 ) Is a front axle of a rail vehicle; at the second controlled axle (A) 2 ) Is greater than a second threshold value (t) 2 ) Second slip value (δ) 2 ) (ii) a Second axle (A) 2 ) To follow the first axle (A) 1 ) And a second threshold value (t) 2 ) Greater than a first threshold value (t) 1 ) (ii) a Based onAn axle (A) 1 ) First adhesion value (mu) between the wheel and the rail 1 ) And a second axle (A) 2 ) Second adhesion value (mu) between the wheel and the rail 2 ) To determine the presence of a plurality of controlled axles (A) n ) A trend of an adhesion curve between the wheel (W) and the rail.)

1. Method for assessing the contamination of a rail, in particular for a rail vehicle, comprising the following steps:

-at a first controlled axle (a) of the rail vehicle₁) Wheel (W)₁) Less than a first predetermined threshold (t) with said rail₁) First slip value (δ)₁) The first controlled axle (A) being dependent on the direction of travel of the rail vehicle₁) Is a front axle of the rail vehicle;

-at the second controlled axle (a)₂) Is greater than a second predetermined threshold (t) with the rail₂) Second slip value (δ)₂) Said second axle (A) depending on the direction of travel of the train₂) To follow the first axle (A)₁) And the second predetermined threshold value (t) of₂) Greater than said first predetermined threshold value (t)₁)；

-based on said first axle (A)₁) Of the wheel and the rail (u) and a first adhesion value (mu) between the wheel and the rail₁) And the second axle (A)₂) And a second adhesion value (mu) between the wheel of (a) and the rail₂) To determine a plurality of controlled axles (A) belonging to said rail vehicle_n) A trend of an adhesion curve between the wheel (W) and the rail.

2. According toMethod for assessing the contamination of rails as claimed in claim 1, wherein a plurality of controlled axles (a) belonging to a rail vehicle are determined (a)_n) The step of trending the adhesion curve between the wheel (W) and the rail comprises the steps of:

-measuring said first axle (a)₁) Of the wheel and the rail (mu) of₁) And said second axle (A)₂) Of the wheel and the rail (mu) of₂)；

-if said second adhesion value (μ) is said₂) Greater than the first adhesion value (mu)₁) Determining a plurality of controlled axles (A) belonging to the rail vehicle_n) Has a profile of adhesion between the wheel (W) and the rail above the second predetermined threshold value (t)₂) Sliding value (delta) of_p) Has an adhesion peak value (mu)_p) The adhesion curve of the trend of (a); and

-if said second adhesion value (μ) is said₂) Less than the first adhesion value (mu)₁) Determining a plurality of controlled axles (A) belonging to the rail vehicle_n) Has a profile of adhesion between the wheel (W) and the rail of less than the first predetermined threshold value (t)₁) Sliding value (delta) of_p) Has an adhesion peak value (mu)_p) The adhesion curve of the trend (c).

3. The method for assessing contamination of a rail according to claim 2, wherein:

a) if a plurality of controlled axles (A) belonging to the rail vehicle have been determined_n) Has a profile of adhesion between the wheel (W) and the rail above the second predetermined threshold value (t)₂) Has a peak adhesion value (mu) at the glide value_p) The trend of (a), the method then comprises the steps of:

-applying between the wheels of all controlled axles and the rail more than the second predetermined threshold (t)₂) A slip value (δ);

b) if a plurality of controlled axles (A) belonging to the rail vehicle have been determined_n) Has a profile of adhesion between the wheel (W) and the rail of less than the first predetermined threshold value (t)₁) Sliding value (delta) of_p) Has an adhesion peak value (mu)_p) The trend of (a), the method then comprises the steps of:

-by means of said first adhesion value (μ)₁) And the second adhesion value (mu)₂) The difference therebetween to calculate an adhesion difference value (Δ μ_slide)；

-at least one third axle (a)₃) Is greater than a second predetermined threshold (t) with the rail₂) Second slip value (δ)₂) Said third axle (A) being dependent on the direction of travel of said train₃) To follow the second axle (A)₂) The axle of (1);

-calculating said third axle (a)₃) Is benefited by the second axle (A)₂) The difference in adhesion force (Δ μ) resulting from the cleaning effect of the wheel_clean) Said difference in adhesion (Δ μ) resulting from said cleaning effect_clean) By means of said third axle (A)₃) Of the wheel and the rail (mu)₃) And the second axle (A)₂) Of the wheel and the rail (mu)₂) The difference is obtained;

-if the difference in adhesion (Δ μ) resulting from the cleaning effect of the wheel is present_clean) Relative to the difference in adhesion (Δ μ)_slide) Multiplying by an adaptation factor (F)_ad) The value of the adaptive factor is inversely proportional to the number of axles, so that all controlled axles (A)₁、...、A_n) Is greater than said second predetermined threshold value (t) and said rail₂) A slip value (δ);

-if the difference in adhesion (Δ μ) resulting from the cleaning effect of the wheel is present_clean) Relative to the difference in adhesion (Δ μ)_slide) Multiplying by an adaptation factor (F)_ad) Not dominant, the value of the adaptive factor is inversely proportional to the number of axles, then in all controlled axles (A)₁、...、A_n) Between the wheel (W) of the vehicle and the railPlus less than said first predetermined threshold (t)₁) The slip value (δ).

4. Method for assessing the contamination of rails according to claim 3, wherein if a plurality of controlled axles (A) belonging to a rail vehicle have been determined_n) Has a traction curve (T) below said first predetermined threshold (t)₁) Sliding value (delta) of_p) Has an adhesion peak value (mu)_p) The adhesion curve of (a), the method then comprising the steps of:

-at all controlled axles (A)₁、...、A_n) Is greater than said second predetermined threshold value (t) and said rail₂) Sliding value (delta) of₂) Thereafter, due to the difference in adhesion (Δ μ) resulting from the cleaning effect of the wheel_clean) Relative to the difference in adhesion (Δ μ)_slide) Multiplying by an adaptation factor (F)_ad) Not dominant, the value of the adaptation factor is inversely proportional to the number of axles if the previous axle (A)_n) Adhesion value (mu) of the wheel_n) In line with the adhesion value of the wheel of the next axle, less than said first predetermined threshold value (t) is applied between the wheel of at least one following axle and said rail₁) First slip value (δ)₁)。

5. Method for assessing the contamination of a rail according to any one of the preceding claims, wherein the method for assessing the contamination of a rail is repeated after a predetermined time interval.

6. The method for assessing contamination of a rail according to any one of claims 1 to 4, wherein the method for assessing contamination of a rail is repeated after the rail vehicle has travelled a predetermined distance.

7. Method for assessing the contamination of a rail according to any one of the preceding claims, wherein the first predetermined threshold value (t;) is₁) Has a glide value of less than 5%, anda second predetermined threshold value (t)₂) With a glide value between 15% and 25%.

8. A method for evaluating the cleanliness of a rail for a rail vehicle, comprising the steps of:

-at a first controlled axle (a) of the rail vehicle₁) Wheel (W)₁) Less than a first predetermined threshold (t) with said rail₁) First slip value (δ)₁) The first controlled axle (A) being dependent on the direction of travel of the rail vehicle₁) Is a front axle of the rail vehicle;

-at the second controlled axle (a)₂) Is greater than a second predetermined threshold (t) with the rail₂) Second slip value (δ)₂) Said second axle (A) depending on the direction of travel of the train₂) To follow the first axle (A)₁) And the second predetermined threshold value (t) of₂) Greater than said first predetermined threshold value (t)₁)；

-at a controlled third axle (a)₃) Is equal to said second value of slip (delta) is applied between the wheel and the rail₂) Third slip value (δ)₃) Said third axle (A)₃) For following the second axle (A) according to the direction of travel of the train₂) The axle of (1);

-based on said second axle (A)₂) Of the wheel and the rail (u) and a first adhesion value (mu) between the wheel and the rail₂) And the third axle (A)₃) And a second adhesion value (mu) between the wheel of (d) and the rail₃) Determining said third axle (A)₃) Advantageously by said second axle (A)₂) Sliding of the rail, resulting in a cleaning effectiveness of the rail.

9. The method for assessing cleaning of a rail for a railway vehicle as claimed in claim 8, wherein the step of determining the effectiveness of the cleaning of the rail comprises the steps of:

-measuring said first adhesion value (μ)₂) And the second adhesion value (mu)₃) (ii) a And

-by applying a second adhesion value (μ) at the second adhesion value₃) And the first adhesion value (mu)₂) To determine the effectiveness of the cleaning.

Technical Field

The present invention relates to the field of methods for controlling adhesion values (adhesion values, adhesion coefficients, sticking coefficients) between wheels and rails of a rail vehicle. In particular, the invention relates to a method for assessing the contamination and cleaning of rails, in particular for rail vehicles.

Background

Electronic systems are installed on most modern rail vehicles, which generally comprise wheel anti-skid control subsystems, which are intended to intervene when the vehicle is in traction phase and in braking phase. These subsystems are referred to as anti-skid or anti-skid systems, also known as WSP (wheel protection against skidding) systems.

In figure 1 of the accompanying drawings, a system for controlling the adhesion of a wheel as an anti-skid function according to the prior art is schematically shown, which relates to a vehicle with n controlled axles a₁、A₂、...、A_nThe vehicle of (1). These axles A₁、A₂、...、A_nComprising respective axes S₁、S₂、...、S_nAnd respective wheel pairs W rotating integrally therewith₁、W₂、...、W_n。

In the drawings, only one wheel per axle is generally shown.

The WSP system of fig. 1 comprises an electronic control unit ECU, typically based on a microprocessor architecture, which derives from the detectors SS respectively associated with such axles₁、SS₂、...、SS_nReceiving and each axle A₁、A₂、...、A_nAngular velocity-related tachometer signal. The electronic control unit ECU is also connected to a torque control device TC₁、TC₂、...、TC_nEach torque control device being associated with a respective axle A₁、A₂、...、A_nAnd (4) associating.

If the wheels of one or more axles end up in a possible incipient slip condition, with the application of torque with reduced grip during traction or braking, the electronic control unit ECU may modulate the torque applied to each axle according to a predetermined algorithm. The torque adjustment is performed in such a way as to prevent the axles from being completely locked, making it possible to bring each axle into a condition of controlled coasting, with the aim of restoring the grip, and in any case for the entire duration of the reduced grip.

In fig. 2, curves 1, 2 and 3 qualitatively represent the adhesion trend according to the environmental conditions: curve 1 corresponds to the adhesion condition under dry contact conditions between the wheel and the rail, curve 2 corresponds to the adhesion condition with the presence of moisture between the wheel and the rail, and curve 3 represents the adhesion condition with the presence of a sticky substance (such as oil or rotten leaves) between the wheel and the rail (typical condition during autumn) or even rust mixed with moisture (typical condition of rail stations).

The experiment shows that the peak value a of the adhesive force₁、a₂、a₃The delta value at (a) varies with changes in the force conditions, moving along the curve as shown in fig. 2 a.

Fig. 3 is a diagram illustrating the force applied to the wheel a of the axle. From this figure it can be clearly seen that:

wherein:

F_A＝μ·m·g (3)

so that:

wherein, F_mFor the tangential force exerted on the wheel by the traction and/or braking system, R is the radius of the wheel, J is the moment of inertia of the axle, and m is the bearing against the wheel railThe mass at the point of contact is,

is the instantaneous angular acceleration of the axle.

It is clear that, at the same instantaneous angular acceleration, the maximum application force F is obtained at the maximum adhesion value μ (i.e. the point located on curve a of fig. 2)_m。

If it is decided to coast the axle under conditions such as that corresponding to point b in fig. 2, the available force F is reduced due to the reduction in the value of the adhesion force μ_mIs reduced, but an energy injection phenomenon is obtained at the point of contact of the wheel and the rail, which energy injection is related to the vehicle speed V_VAnd the tangential velocity V of the wheel_rIn proportion to the glide (difference) between and with power (energy injected per unit time):

P(δ)＝F_A(δ)·(V_v-V_r)＝μ(δ)·m·g·(V_v-V_r)＝μ(δ)·m·g·δ·V_v. (5)

expression (5) above shows how the power applied to the wheel-rail contact point is increased by increasing δ. The injection of energy causes the wheel to overheat, with consequent cleaning of the contact points, increasing the instantaneous adhesion value μ of the next wheel.

Furthermore, it is known that in the presence of moisture or rain, a significant cleaning effect is obtained, whereas in the presence of lubricants or rotten leaves, the cleaning effect is poor.

Current systems for restoring the adhesion between the wheel and the rail impose a fixed sliding value δ, generally between 0.2 and 0.3, which is calibrated in a determinate manner during the vehicle sizing tests. The chosen delta value is therefore optimized for the type of lubricant used to cause the slip condition during the test, as specified for example in "EN 15595:2009+ a1, track application-brake-wheel slide protection, paragraph 6.4.2.1", and on the other hand is not the best choice for all types of materials that may cause the slip condition during normal use of the vehicle.

The graph of FIG. 4A qualitatively illustratesHow the peak value of the overall adhesion of a vehicle with four axles varies with the variation of δ: as shown in fig. 4A, all the axles are made to correspond to the value δ₁Because there is virtually no cleaning factor, the four adhesion curves corresponding to the four wheels substantially coincide with each other, and each axle utilizes the maximum peak adhesion value μ (δ) for each axle₁)。

On the other hand, if the axle is made to correspond to the coasting value δ as shown in fig. 4B₂The adhesive force of the cleaning agent slides, so that a higher cleaning factor can be obtained: mu corresponding to only the first axle of the vehicle₁The curve (in the direction of travel) will remain unchanged and is equivalent to that of figure 4A, whereas the adhesion value corresponding to the curve of the following axle will increase due to the cleaning effect achieved by the previous axle. Value μ (δ) per axle₂) Is actually smaller than the corresponding value mu (delta)₁)。

Qualitatively as shown in FIG. 4C, in the range δ₁≤δ≤δ₂In (1), there is a peak average bulk adhesion value

The above description is applicable by extension to a vehicle or train having n axles.

Since the curve representing the adhesion force μ as a function of the creep value δ may not be analytically mathematically formulated and may continuously vary with the conditions causing the creep, the geometry of the contact points and the external environmental conditions, it is not possible to analytically calculate the optimum creep value δ a priori.

However, an excellent adhesion control and possible recovery system should be able to analyze the instantaneous adhesion conditions in real time and verify their trend as a function of δ and determine the value of δ so that it is suitable for use in a vehicle

And (4) maximizing. This value is a value that allows the maximum adhesion force to recover in the case of slipping, and is a value that minimizes the stopping distance when braking in the case of a drop in adhesion force.

To obviate the above problem, WO 2006/113954 a describes a coasting control for a rail vehicle, which is continuously implemented over time, which requires the determination of the necessary parameters under optimal adhesion conditions, according to the required performance under subsequent slipping conditions. This approach also requires that the overall deceleration of the system be known.

Furthermore, the process of adjusting the optimum glide value requires a considerable amount of time. The adjustment process is carried out at the beginning of the slip phase, i.e. when the vehicle is travelling at high speed, the distance covered by the latter being greatly increased.

In addition, the processes and systems implemented according to the prior art are based on the assumption that the wheel adhesion curve always has an adhesion peak μ at small values of slip (e.g. about 1-2%)_pCurve (c) of (d).

In fact, the wheel adhesion curve does not always have a peak adhesion μ at small sliding values_pThe curve of (d); they may have an adhesion peak μ at higher glide values (such as values of about 20-25%)_pCurve (c) of (d).

In the second case, if the curve is mistakenly regarded as having a peak adhesion μ at a small glide value_pI.e., a small value of slip is applied between the wheel and rail to obtain peak wheel adhesion, the desired benefit is not realized. In fact, in small coasting, the curve has μ at higher values of coasting (e.g., values of about 20-25%)_pAnd thus exhibits a poor level of adhesion and poor rail cleaning (given the low glide values applied).

Thus, in the second case, the average adhesion value will not be the optimal value, considering each single adhesion value of the wheel.

Disclosure of Invention

The object of the present invention is to propose a method for assessing the soiling of a rail which allows the location of adhesion peaks to be determined along the adhesion curve of the wheels belonging to a plurality of controlled axles of a vehicle and, therefore, to obtain improved control and possible restoration of the wheel adhesion of a controlled axle of a rail vehicle, and a method for assessing rail cleaning which allows a better assessment of the cleaning effect between various successive axles of a rail vehicle.

The above and other objects and advantages are achieved according to one aspect of the present invention by a method for assessing the contamination of rails having the features defined in claim 1 and by a method for assessing the cleaning of rails having the features defined in claim 8. Preferred embodiments of the invention are defined in the dependent claims, the contents of which are intended to be an integral part of the present description.

Drawings

Other features and advantages of the invention will become apparent from the following detailed description, which is provided by way of non-limiting example only, with reference to the accompanying drawings, in which:

figure 1 is a block diagram of an anti-skid control system of the wheels of a rail vehicle;

fig. 2 is a graph qualitatively showing the trend of the traction coefficient μ of the wheel of the axle shown on the y-axis as a function of the slip value δ shown on the x-axis;

figure 3 is a schematic view illustrating the forces exerted on the wheels of the axle;

4A, 4B are graphs qualitatively showing the trend of the grip coefficient μ of the wheels of the four axles of the vehicle under two different operating conditions;

FIG. 4C shows the average adhesion curve around the peak

A trend of (a);

figure 5 is a graph showing an adhesion curve with a peak of adhesion at a glide value lower than a first predetermined threshold value;

FIG. 6 is a graph showing an adhesion curve with a peak of adhesion at a glide value greater than a second predetermined threshold value;

fig. 7 shows four adhesion curves of the wheels belonging to four consecutive axles, respectively, in this case with the cleaning effect of the rail;

fig. 8 shows four adhesion curves of the wheels belonging to four consecutive axles respectively, in which case the coasting value is applied corresponding to the adhesion peak between the wheel of the axle and the rail and therefore there is no cleaning effect of the rail;

fig. 9 shows four adhesion curves of the wheels belonging respectively to four consecutive axles, in which case the adhesion curves of the wheels belonging to a plurality of controlled axles of the rail vehicle exhibit an adhesion peak at a skid value lower than a first predetermined threshold value, and the skid value applied between the wheels of the axle and the rail is a higher skid value than a second predetermined threshold value; and

fig. 10 shows four adhesion curves of the wheels belonging to four consecutive axles respectively, in which case the adhesion curves exhibit adhesion peaks at a skid value greater than a second predetermined threshold value, and the skid value applied between the wheels of the axle and the rail is a higher skid value than the second predetermined threshold value.

Detailed Description

Before explaining several embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology are for the purpose of description and should not be regarded as limiting. The use of "including" and "comprising" and variations thereof is understood to encompass the elements described below and equivalents thereof, as well as additional elements and equivalents thereof.

As will be more apparent from the following, the method according to the invention allows determining the position of the adhesion peak along the adhesion curve of the wheels belonging to a plurality of controlled axles of the vehicle and thus obtaining an improved control and possible restoration of the adhesion of the wheels of the controlled axles of the rail vehicle.

Referring first to an adhesion curve such as that in FIG. 5, additional adhesion is obtained for smaller glide values of about 1-2%Peak value of force application mu_p。

Will delta_pDefined as obtaining the peak adhesion μ_pThe glide value of (d), obviously:

if the axle is brought close to δ_p(small glide value) glide, the peak value mu is adopted_pThe local adhesion is negligible.

Conversely, if the axle is made to coast at a higher value of glide δ, the local adhesion beneficial to the possible cleaning effect of the following axle will be lost. This effect will be more or less effective depending on the type and amount of contaminants present. The effectiveness of the cleaning is a priori unknown data.

Therefore, in order to maximize the average adhesion of the axle, selecting a coast point for the axle to operate generally must take into account two factors:

1. the benefit of cleaning the following axle (increased with increased local glide); and

2. local adhesion values (decreasing with increasing glide).

In contrast, in the case of the adhesion curve shown in fig. 6, the trend of the adhesion curve, as seen from literature and from experimental test results on rolling stock, depends on a number of factors, including: the type of pollutant, the amount of pollutant, and the weight of the vehicle. As shown in FIG. 5, for small glide values, not all adhesion curves must exhibit an adhesion peak μ_p. There is a sliding value (delta) for higher_p20%) to obtain the adhesion peak mu_pAs shown by the curves in fig. 6.

In this case:

if the axle is made to coast at a small value of coasting (e.g. δ -1-2%), the cleaning effect will be practically zero and the local adhesion will be reduced with respect to the peak.

Conversely, if the axle is made to coast at a higher value δ (δ ≈ 20%, for example), it will be beneficial both for the local adhesion and for the possible cleaning effect of the following axle.

Thus, for the adhesion curve shown in FIG. 6, regardless of whether it is clearHow effective the cleaning is, the most suitable choice is to have a large value of slip for all axles (δ ≈ 20% ≈ δ)_p) To maximize the local adhesion and possible cleaning effect.

Based on the above concept, a method for assessing the contamination of a rail, in particular for a rail vehicle, comprises the following steps:

-at a first controlled axle a of the rail vehicle₁Wheel W of₁Less than a first predetermined threshold t applied to the rail₁First slip value δ₁First controlled axle A, according to the direction of travel of the rail vehicle₁Is a front axle of a rail vehicle;

at the second controlled axle A₂Is greater than a second predetermined threshold t₂Second slip value δ₂The second axle A according to the running direction of the train₂To follow the first axle A₁And a second predetermined threshold t₂Greater than said first predetermined threshold t₁；

Based on the first axle A₁First adhesion value mu between wheel and rail₁And the second axle A₂Second adhesion value mu between wheel and rail₂To determine a plurality of controlled axles A belonging to the rail vehicle_nThe tendency of the adhesion curve between the wheel W and the rail.

Determining a plurality of controlled axles A belonging to a rail vehicle_nThe step of trending the adhesion curve between the wheel W and the rail may further comprise the steps of: measuring the first axle A₁First adhesion value mu between wheel and rail₁And the second axle A₂Second adhesion value mu between wheel and rail₂；

If the second adhesion value mu₂Greater than the first adhesion value mu₁Determining a plurality of controlled axles A belonging to the rail vehicle_nHas a profile of adhesion between the wheel W and the rail greater than a second predetermined threshold t₂Sliding value delta of_pHas a peak value of adhesive force mu_pAttached to the trend ofAn impact curve; and

if the second adhesion value mu₂Less than the first adhesion value mu₁Determining a plurality of controlled axles A belonging to the rail vehicle_nHas a profile of adhesion between the wheel W and the rail of less than said first predetermined threshold t₁Sliding value delta of_pHas a peak value of adhesive force mu_pThe adhesion curve of the trend (c).

For example, the first predetermined threshold t₁May correspond to a coasting value of about 5% and at the first controlled axle a₁A first slip value delta between the wheel and the rail of less than a first predetermined threshold value₁May be about 1-2%. Second predetermined threshold t₂May correspond to a coasting value of between about 15% and 25%, and at the at least one second controlled axle a₂A second slip value delta between the wheel and the rail greater than a second predetermined threshold value₂And may be about 20% to about 25%.

Preferably, the second slip value δ₂A limit glide value delta not exceeding or equal to about 25%_limit。

If a plurality of controlled axles A belonging to the rail vehicle have been determined_nHas a profile of adhesion between the wheel W and the rail greater than a second predetermined threshold t₂Shows a peak value mu of adhesion at the glide value_pThe adhesion curve of the trend, the method for evaluating the contamination of the rail may comprise the following steps:

-applying between the wheels and the rails of all controlled axles a value greater than a second predetermined threshold t₂The glide value δ.

On the other hand, if it has been determined that a plurality of controlled axles A belong to a rail vehicle_nHas a profile of adhesion between the wheel W and the rail of less than a first predetermined threshold t₁Sliding value delta of_pHas a peak value of adhesive force mu_pThe adhesion curve of the trend, the method for evaluating the contamination of the rail may comprise the following steps:

by means of a first adhesion value mu₁And a second adhesion value mu₂The difference therebetween to calculate an adhesion difference Δ μ_slide；

At least one third axle A₃Is greater than a second predetermined threshold t₂Second slip value δ₂According to the direction of travel of the train, the third axle A₃To follow the second axle A₂The axle of (1);

calculating the third axle A₃Is benefited by the second axle A₂The difference of adhesion force delta mu generated by the cleaning effect of the wheel_cleanThe difference in adhesion Δ μ resulting from the cleaning effect_cleanBy means of a third axle A₃Of the wheel and rail of₃And a second axle A₂Of the wheel and rail of₂The difference is obtained;

if the difference in adhesion Δ μ results from the cleaning effect of the wheel_cleanRelative to the difference in adhesion Δ μ_slideMultiplication by an adaptation factor F_ad(the value of the adaptive factor is inversely proportional to the number of axles) predominates, then in all controlled axles A₁、...、A_nIs greater than a second predetermined threshold t₂The glide value δ of;

if the difference in adhesion Δ μ results from the cleaning effect of the wheel_cleanRelative to the difference in adhesion Δ μ_slideMultiplication by an adaptation factor F_ad(the value of the adaptive factor is inversely proportional to the number of axles) is not dominant, then all controlled axles A are₁、...、A_nIs less than a first predetermined threshold t₁The glide value δ.

If a plurality of controlled axles A belonging to the rail vehicle have been determined_nHas a traction curve with a traction curve smaller than a first predetermined threshold t₁Sliding value delta of_pHas a peak value of adhesive force mu_pThe adhesion curve of (a), the method for evaluating the contamination of a rail may comprise the steps of:

at all controlled axles A₁、...、A₀Is greater than a second predetermined threshold t₂Sliding value delta of₂Thereafter, the difference in adhesion Δ μ due to the cleaning effect of the wheel_cleanRelative to the difference in adhesion Δ μ_slideMultiplication by an adaptation factor F_ad(the value of the adaptive factor is inversely proportional to the number of axles) is less dominant if the previous axle A_nAdhesion value mu of the wheel_nWith the next axle A_n+1Adhesion value mu of the wheel_n+1In agreement, then on at least one following axle A_n+1、A_n+2Between the wheel and the rail of less than a first predetermined threshold t₁First slip value δ₁。

It is noted that, thanks to the last step described above, the cleaning effect of the rails exhibited on the first axle according to the direction of travel is no longer related to the increase in adhesion of the following axle (for example, because the rails are now completely clean), and therefore it is appropriate to impose on the following axle a value of slippages corresponding to the peak of adhesion, instead of the value of slippages useful for cleaning the rails.

For example, consider the second axle as the previous axle A_nAnd the third axle is regarded as the following axle a_n+1Greater than a second predetermined threshold t is imposed between the wheels and the rails of all the controlled axles₂Sliding value delta of₂Thereafter, the difference in adhesion Δ μ due to the cleaning effect of the wheel_cleanRelative to the difference in adhesion Δ μ_slideMultiplication by an adaptation factor F_adNot predominating, therefore if the second axle A₂(front axle A)_n) Adhesion value mu of the wheel₂And a third axle (follower axle A)_n+1) Adhesion value mu of the wheel₃In agreement, then less than the first predetermined threshold t is imposed between the wheel and the rail following the axle of the third axle₁First slip value δ₁。

For example, the method of assessing rail contamination may be repeated after a predetermined time interval (e.g., every 30 seconds), or may be repeated after the rail vehicle has traveled a predetermined distance.

Furthermore, the invention comprises a method for evaluating the cleanliness of a rail for a rail vehicle, comprising the steps of:

-at a first controlled axle a of the rail vehicle₁Wheel W of₁Less than a first predetermined threshold t applied to the rail₁First slip value δ₁(ii) a According to the direction of travel of the rail vehicle, a first controlled axle A₁Is a front axle of a rail vehicle;

at the second controlled axle A₂Is greater than a second predetermined threshold t₂Second slip value δ₂The second axle A according to the running direction of the train₂To follow the first axle A₁And the second predetermined threshold t₂Greater than said first predetermined threshold t₁；

At a controlled third axle A₃Is equal to said second slip value delta₂Third slip value δ₃Third axle A₃To follow the second axle A according to the driving direction of the train₂The axle of (1);

based on the second axle A₂First adhesion value mu between wheel and rail₂And the third axle A₃And a second adhesion value mu between the wheel and the rail₃Determining a third axle A₃Beneficially by said second axle a₂The sliding of (a) results in a cleaning effectiveness of the rails.

The step of determining the effectiveness of the cleaning of the rail may comprise the steps of:

-measuring a first adhesion value μ₂And a second adhesion value mu₃(ii) a And

by applying a second adhesion value mu₃And a first adhesion value mu₂To determine the effectiveness of the cleaning.

An exemplary case in which the total number of axles of the rail vehicle is four is reported below by way of example.

Considering fig. 7, the adhesion of the four axles that make up the rail vehicle can be evaluated.

Can be used for the first vehicleAxis A₁Adhesive force mu of₁Unaffected by cleaning, the axle that first encounters the rail. Adhesion force mu₁Only on the condition of the rail, i.e. the environmental/contamination condition which will be indicated below with "amb".

Thus, the adhesion force μ engaged by the first axle₁Will be a partial coasting delta of the first axle on the rail₁Function of (c):

μ₁＝f(μ_max,δ₁)＝f(amb，δ₁)

in contrast, the adhesion force μ available for the second axle₂Dependent on the cleaning (Δ μ) produced by the preceding first axle₁₂)。

μ_2，max＝μ_max+Δμ₁₂

Facilitating cleaning of the second axle by the first axle₁₂Is the value delta of the first axle's glide on the rail₁And the typical cleaning characteristics of the contaminants (contaminants are more or less easily removed with the same glide) which are indicated hereinafter by the term "cleaning".

μ_2，max＝μ_max+ f (clean, δ₁)

Thus, the adhesion force μ engaged by the second axle₂Will be a partial coasting delta of the second axle on the rail₂As a function of (c).

μ₂＝f(μ_2，max,δ₂)＝f(amb，δ₁Cleaning, delta₂)

Likewise, the adhesion force μ engaged by the third axle₃Dependent on the local slip value delta₃And those generated by the front axle, and is therefore dependent on delta₁、δ₂And cleaning.

Likewise, the adhesion force μ engaged by the fourth axle₄Dependent on the local slip value delta₄And those generated by the front axle, and is therefore dependent on delta₁、δ₂、δ₃And cleaning.

In light of these considerations:

in the case of the adhesion curve shown in fig. 5, and with the peak of adhesion μ applied on all the axles_pIn the case of corresponding coasting, it is assumed (see fig. 8) that all axles are controlled to the adhesion peak μ_pAbove, i.e. at δ_pA small value of glide near this will not produce rail cleaning.

Δμ₁₂＝Δμ₂₃＝Δμ₃₄＝0

Therefore, the temperature of the molten metal is controlled,

μ_2，max＝μ_3，max＝μ_4，max＝μ_1，max

all axles have the same adhesion as the front axle (first axle in the direction of travel) because none of the axles clean the rails.

So that:

μ_average＝μ_1，max

in the case of the adhesion curve as shown in fig. 5, in which the creep value δ is imposed on all the axles>>δ_pIt is possible to obtain a cleaning effect (this effect is of course not a priori, but depends on the effectiveness of the cleaning-related contaminants: a parameter previously defined as "cleaning").

Referring to fig. 9:

Δμ₁₂＝Δμ₂₃＝Δμ₂₃＝Δμ_clean

thus:

μ_2，max＝μ_1，max+Δμ_clean

μ_3，max＝μ_2，max+Δμ_clean＝μ_1，max+2*Δμ_clean

μ_4，max＝μ_3，max+Δμ_clean＝μ_1，max+3*Δμ_clean

at the same time, to be away from the peak value delta_pWill not benefit each axle of delta coastAll locally available adhesion forces μ are used.

Referring to fig. 9:

μ₁＝μ_1，max-Δμ_slide

μ₂＝μ_2，max-Δμ_slide＝μ_1，max+Δμ_clean-Δμ_slide

μ₃＝μ_3，max-Δμ_slide＝μ_1，max+2*Δμ_clean-Δμ_slide

μ₄＝μ_4，max-Δμ_slide＝μ_1，max+3*Δμ_clean-Δμ_slide

calculating the average adhesion of the vehicle:

comparison of the case of the adhesion curves shown in fig. 5, the case of applying a creep value corresponding to the adhesion peak on all the axles, and the case of applying a creep value δ on all the axles>>δ_pThe average adhesion obtained in the case of (1), wherein it is noted that:

if is

Then by delta>>δ_pControl the axle at a value greater than a second predetermined threshold t₂Is suitable for controlling the axle.

If is

Then with a reduced glide value δ_pI.e. to be less than a first predetermined threshold t₁The coasting value of (c) controls the axle, which is appropriate.

In the example given above, the adaptation factor is equal to 2/3. For example, in the case of five axles, the adaptation factor is equal to 1/2.

For the adhesion curve as shown in fig. 6Line, whatever the effectiveness of the cleaning, the most suitable choice is to have all the axles with a large value of creep, i.e. greater than a second predetermined threshold t₂(δ≈20％≈δ_p) Thus maximizing the local adhesion and possible cleaning effect.

From this management of the sliding points (see fig. 10), we have:

μ₁＝μ_1，max

μ₂＝μ_1，max+Δμ_clean

μ₃＝μ_1，max+2*Δμ_clean

μ₄＝μ_1，max+3*Δμ_clean

thus, the average vehicle horizontal adhesion is:

from an analysis of the previous case, (as in the case of the adhesion curve shown in fig. 5, and in which the coasting value corresponding to the adhesion peak is applied on all the axles, for the case of the adhesion curve shown in fig. 5, in which δ is applied on all the axles>>δ_pAnd for the case of the adhesion curve as shown in fig. 6), it is noted that the choice of the optimal sliding point (the choice of maximizing the average adhesion of the vehicle) must be evaluated by three main factors:

factor 1: type of adhesion curve: i.e. whether for small glide values (fig. 5) (i.e. for values smaller than a first predetermined threshold t)₁For a slip value) or for a large slip value (fig. 6) (i.e. for values greater than a second predetermined threshold value t)₂Sliding value of, close to delta_limit) Obtaining the adhesion peak value;

factor 2: Δ μ_slide(parameters defined only for the curves shown in fig. 5), i.e. the difference in adhesion between the peak of the curve and the adhesion engaged with the glide value close to the limit glide (see fig. 9).

Factor 3:Δμ_cleani.e. when the axle n is made to be greater than a second predetermined threshold t₂Is close to delta_limitThe effectiveness of the cleaning effect that axle (n +1) benefits from when coasting.

In the case of a rail vehicle running on a rail, the evaluation of these three factors and the consequent selection of the slip point must be carried out in real time during the braking of the vehicle, according to the criteria described above, in order to maximize the average adhesion force of the vehicle engagement, to maximize the deceleration of the vehicle and to minimize the stopping distance of the vehicle.

In order to evaluate the effectiveness of the cleaning (factor 3), it is therefore necessary to impose an effective glide value on the axle n, i.e. greater than a second predetermined threshold t₂Sliding value of (delta ≈ delta)_limit) And the potential adhesion gain on the axle (n +1) is verified.

At the same time, by making the axle greater than a second predetermined threshold t₂Sliding value of (approximately delta)_limit) Coasting, modifying the rail conditions for the following axles, and failing to evaluate the value with respect to small coasting (i.e. less than the first predetermined threshold t)₁(δ<5%) slip value). Therefore, factors 1 and 2 cannot be evaluated.

The object of the invention is to manage the coasting of the axles as follows:

a first axle: delta₁≈1-2％

A second axle: delta₂≈20％

A third axle: delta₃＝δ₂≈20％

A fourth axle: optionally

The first axle and the front axle are controlled with a small coasting value. Thus, by measuring the adhesion force engaging the first axle, an adhesion force value relative to a small slip value may be obtained

μ₁＝μ(1-2％)

But without producing cleaning, i.e. without changing the rail properties of the following axle.

On the other hand, the second axle is controlled with an effective creep value, i.e. with a value greater than a second predetermined threshold value t₂Is not too muchThe row value is controlled. Thus, by measuring the adhesion force engaging the second axle, an adhesion force value relative to a large slip value may be obtained

μ₂＝μ(20％)

Resulting in a possible cleaning of the trailing axle, which depends on the nature of the contamination (cleaning factor 3).

The third axle is controlled with the same creep value applied to the second axle.

Thus, by measuring the adhesion force engaging the third axle, the cleaning factor may be calculated.

To evaluate the effectiveness of the cleaning:

Δμ_clean＝μ₃-μ₂

furthermore, by comparing the measured adhesion forces of the first and second axle, the type of adhesion curve (factor 1) can be determined and it is possible to calculate Δ μ_slide(factor 2).

If (mu)₂>μ₁) This is the case for an adhesion curve of the type shown in fig. 6.

Therefore, the most suitable choice is to have all axles with a large amount of slippage, i.e. greater than the second predetermined threshold t₂Sliding quantity of (delta ≈ 20% ≈ delta)_limit)；

If (mu)₂>μ₁) This is the case for an adhesion curve of the type shown in fig. 5, and it can be calculated:

Δμ_slide＝μ₁-μ₂

at this point, it is noted that for all factors, the optimal glide point can be selected:

if it is not

Therefore, the most suitable choice is to have all axles with a large value of creep, i.e. greater than the second predetermined threshold t₂Sliding value of (delta ≈ 20% ≈ delta)_limit)；

If it is not

The most suitable option is to control the axle at the adhesion peak, i.e. at less than a first predetermined threshold t₁Sliding value (delta) of<5%) slide.

Naturally, without altering the principle of the invention, the embodiments and the implementation details may vary widely with respect to those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the present invention as defined in the appended claims. Further, it is to be understood that each embodiment may be combined with any other embodiment.