DE102017004851A1 - Method for determining a drive of a vehicle tire of a vehicle - Google Patents

Abstract

The invention relates to a method for determining an abrasion of a vehicle tire of a vehicle, in which current Radumdrehungen be determined with speed sensors. In one method, the vehicle may automatically determine tire wear when an accurate tire size is input to the vehicle, from which a rolling circumference is determined to be multiplied by wheel revolutions over a traveled distance, and from the distance covered an actual engine speed is determined Abrasion of the vehicle tire is closed when the engine speed is higher than a predetermined engine speed.

Description

The invention relates to a method for determining an abrasion of a vehicle tire of a vehicle, in which current wheel revolutions are determined by means of speed sensors.

From the DE 32 36 520 A1 a device for indicating the condition of vehicle tires is known, with which in the vehicle long-term changes in the tire condition in the form of tire wear are detected. In this case, in a predefined vehicle state, the stored reference speed determined with a given driving state is compared with sensor signals as a function of the respective driving speed.

Very powerful vehicles, which already have high wheel torques in the low engine speed range, have the problem of high tire wear. Vehicles driven by electric motors in particular have the peculiarity of already applying the full engine torque at low rotational speeds, as a result of which tire wear increases greatly.

The object of the invention is to provide a method for determining an abrasion of a vehicle tire of a vehicle, in which without additional aids the tire wear is detected by the vehicle itself.

The invention results from the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims. Other features, applications and advantages of the invention will become apparent from the following description, as well as the explanation of embodiments of the invention, which are illustrated in the figures.

The object is achieved with a method in that an exact tire designation is entered into the vehicle, from which a rolling circumference is determined, which is multiplied by wheel revolutions over a traveled distance, wherein a current engine speed is determined from the distance covered and an abrasion the vehicle tire is closed when the engine speed is higher than a predetermined engine speed. The solution is based on the recognition that wear on the tire higher engine speeds caused, as this is in a fixed relationship to the decreasing tire circumference. Since all the necessary parameters for the determination of the tire wear in the vehicle are known, the abrasion can be automatically determined in the vehicle. This is particularly important for vehicles with an electric motor drive, as they have a fast tire wear.

Advantageously, when determining the current engine speed and the predetermined engine speed, the vehicle travels the same distance, wherein the predetermined engine speed is determined after shoring at least one new or used tire on the vehicle. By using the same observation distance, the accuracy in determining the tire abrasion is increased.

In one embodiment, the distance covered is averaged over the tires of a vehicle. As a result, cornering is smoothed, where the individual wheels cover different distances.

In a development, the distance traveled necessary for the calculation is determined in-vehicle or via GPS

In one embodiment, the predetermined engine speed is determined in a calibration process. Such a calibration measurement takes into account deviations of a new tire from a nominal dimension in the calculations.

In one variant, a matrix is stored in the vehicle which assigns a rolling circumference, which is characterized by a tire type, to a rolling circumference, from which the engine speed is taken into account taking account of gear information. By means of this matrix, the vehicle is informed of the rolling circumferences of the most varied tire types, wherein the vehicle, after notifying the tire type in a variant coding, can assign the correct rolling circumference to the newly installed tire set.

In a further development, from a minimum tread depth of the vehicle tire of a given tire type to a maximum predetermined engine speed is concluded, when exceeding the maximum predetermined engine speed by the current engine speed a warning signal is output. The Warning signal can be issued visually or acoustically in the vehicle itself or transmitted via the Internet directly to the vehicle workshop.

A particularly accurate conclusion to a worn tire is possible if a difference between the current and the maximum predetermined engine speed is formed, and when exceeding a difference threshold is considered by the difference of the tires as worn.

In one embodiment, the current engine speed for each tire of the vehicle is determined separately, since the tire profiles are traversed differently.

In a further embodiment, the current engine speed is determined at a mean engine torque and / or a predetermined vehicle speed range and / or at a higher gear and / or at the correct air pressure. As a result, distortions of the measurement result are prevented, for example, by larger accelerations or delays.

In a further development, a maximum speed limit of the vehicle is automatically reached when the maximum predetermined engine speed corresponding to a minimum tread depth is reached. This is particularly important for autonomous vehicles, where no driver exists, which can respond to warning signals.

The safety of the vehicle is particularly enhanced when the speed limit is selected depending on the road conditions. In particular, rain or ice as well as poor structural road conditions can be taken into account. After a tire change, the speed limit is canceled again.

Further advantages, features and details will become apparent from the following description in which at least one embodiment is described in detail. Described and / or illustrated features may form the subject of the invention itself or in any meaningful combination, optionally also independent of the claims, and in particular may also be the subject of one or more separate application / s.

For determining an abrasion of a vehicle tire of a vehicle, an accurate tire type such as 215 / 50R17 is input to a controller of the vehicle, whereby the vehicle can determine the exact tire size of the tires with which the vehicle is equipped. For this purpose, a matrix is stored in a memory of the control unit, which assigns each tire type a rolling circumference of the tire.

The matrix is shown in excerpts in Table 1. Table 1 Rolling circumference Series 80 Series 70 ... Series 30 1550 125R12 145 / 70R12 1560 155 / 70R12 1580 135 / 70R12 1590 135R12 , , 1970 165R15 185 / 70R15 215 / 50R17 , , 2250 295 / 30R22 2290 265 / 70R15

For this purpose, a variant coding is entered into the engine control unit designed as a control unit, it being distinguished whether it is new tires or used tires. From the tire size results in a rolling circumference. After multiplication with the wheel revolutions, which are determined by wheel speed sensors present in the vehicle. If there is a covered distance of the vehicle. This route can alternatively be determined via GPS. This distance is now compared with an engine speed and a gear information. The gear information contains the overall ratio of the gear, taking into account the axle drive. A new type 215 / 50R17 tire, as shown in Table 1, has a rolling circumference of 1970 mm, which corresponds to a tire diameter of a new 627 mm tire. In a 5th gear, the engine speed is 2000 rpm, with the vehicle driving exactly at a speed of 150 km / h.

A new profile height of the tire is, for example, 8 mm. The limit abrasion is achieved, for example, at 3 mm. This means that the tire diameter decreases by 10 mm to 617 mm after the maximum abrasion. The rolling circumference of the tire is reduced to 1938 mm. The wear on the tire at a vehicle speed of 150 km / h in 5th gear higher engine speeds, as these are in a fixed ratio to the decreasing tire circumference. The changes in the circumference of a new tire to a worn tire and thus an engine speed change is set over a predetermined observation distance of, for example, 2000 m. If the engine speed reaches a higher engine speed than 2000 rpm at a speed of 150 km / h in 5th gear, the difference to the higher engine speed is determined. This difference is compared with a difference threshold. If the difference exceeds the difference threshold value of the engine speed, the tire is considered worn.

The observation distance is averaged between the wheels to smooth cornering. The test is carried out at a mean engine torque and in a speed window of the vehicle, for example 70-100 km / h. It should be resorted to the 4th, 5th or 6th gear. The calculation is done separately for each tire, since they run their profiles differently.

If a wear of the tire is detected, a warning signal is issued to the driver in the vehicle. The warning signal can also be transmitted via the Internet directly to the workshop of the vehicle.

Since no vehicle driver drives in the vehicle when the vehicle is traveling autonomously, the maximum vehicle speed is automatically limited when the tire is detected. This limit is canceled after a tire change.

To allow possible deviations from the nominal size of a new tire within the tolerances to be included in the calculations, a calibration measurement is carried out before the actual measurement. In the case of used tires, the matrix (Table 1) is used and wear is determined on the basis of the matrix.

Due to the monitoring of the engine speed over a predetermined distance and at a specified gear, the vehicle can automatically close to a tire wear.

Although the invention has been further illustrated and explained in detail by way of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. It is therefore clear that a multitude of possible variations exists. It is also to be understood that exemplified embodiments are really only examples that are not to be construed in any way as limiting the scope, applicability, or configuration of the invention. Rather, the foregoing description and description of the figures enable one skilled in the art to practice the exemplary embodiments, and those of skill in the knowledge of the disclosed inventive concept may make various changes, for example, to the operation or arrangement of particular elements recited in an exemplary embodiment, without Protected area, which is defined by the claims and their legal equivalents, such as further explanation in the description.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3236520 A1 [0002]

Claims (10)

A method for determining an abrasion of a vehicle tire of a vehicle, in which current wheel revolutions are determined with speed sensors, characterized in that an accurate tire size is input to the vehicle, from which a rolling circumference is determined, which is multiplied by wheel revolutions over a traveled distance, from the distance traveled, a current engine speed is determined and is closed to abrasion of the vehicle tire, when the engine speed is higher than a predetermined engine speed. A method according to claim 1, characterized in that when determining the current engine speed and the predetermined engine speed, the vehicle travels the same distance and the predetermined engine speed is determined after shoring at least one new or used tire on the vehicle. A method according to claim 2, characterized in that the distance traveled over the tires of a vehicle is averaged. A method according to claim 1, 2 or 3, characterized in that the predetermined engine speed is determined in a calibration process. Method according to at least one of the preceding claims, characterized in that a matrix is stored in the vehicle, which assigns a tire size characterized by a tire type a rolling circumference, from which, taking into account a gear information on the engine speed is concluded. The method of claim 1, 2 or 3, characterized in that it is concluded from a minimum profile depth of the vehicle tire of a given tire type to a maximum predetermined engine speed, wherein when exceeding the maximum predetermined engine speed, a warning signal is output. Method according to at least one of the preceding claims, characterized in that a difference between the current and the maximum predetermined engine speed is formed, wherein when exceeding a difference threshold value is considered by the difference of the tires as worn. Method according to at least one of the preceding claims, characterized in that the current engine speed is determined separately for each individual tire of the vehicle. Method according to at least one of the preceding claims, characterized in that the current engine speed at an average engine torque and / or a predetermined vehicle speed range and / or at a higher gear and / or a correct air pressure is determined. Method according to at least one of the preceding claims, characterized in that upon reaching the maximum, corresponding to a minimum tread depth predetermined engine speed is automatically a speed limit of the vehicle.