POWER TRANSMISSION SYSTEM HAVING DELIBERATE DRIVE TORQUE PROVISION

Abstract

A transmission system for a vehicle including a drive, at least one wheel and at least one brake having an ABS system. The drive is configured to drive the at least one wheel and the at least one brake is configured to brake the at least one wheel. The power transmission system is configured to also drive the at least one wheel braked by the at least one brake during a braking process, which enters a control range of the ABS system, at the same time using a drive torque.

Claims

1. A power transmission system for a vehicle comprising a drive, at least one wheel and at least one brake having an ABS system, wherein the drive is configured to drive the at least one wheel and the at least one brake is configured to brake the at least one wheel, wherein the power transmission system is configured to also drive the at least one wheel braked by the at least one brake during a braking process, which enters a control range of the ABS system, at the same time using a drive torque.

2. The power transmission system as claimed in claim 1, wherein the power transmission system is configured to overcompensate for the drive torque during the braking process.

3. The power transmission system as claimed in claim 1, wherein the power transmission system comprises an acquisition unit which is configured to acquire a power transmission or a slip of the at least one wheel on a roadway.

4. The power transmission system as claimed in claim 1, wherein the power transmission system comprises an ascertainment unit which is configured to ascertain a need to provide a drive torque.

5. The power transmission system as claimed in claim 1, wherein the power transmission system comprises at least one additional sensor which configured to acquire at least one further measured value, wherein the power transmission system comprises a determination unit, which is configured to compare a speed of the at least one wheel in consideration of the at least one further measured value.

6. The power transmission system as claimed in claim 1, wherein the determination unit is configured to carry out the respective comparison of the speed of the at least one wheel in conjunction with modeling of an optimum speed of the wheel determined from the currently expected slip.

7. A method for maximizing a power transmission from a wheel to a roadway using a power transmission system as claimed claim 3, comprising the steps: determining a speed of the at least one wheel; determining a vehicle speed from the determined speed and a deviation of the present speed from an optimal speed or an optimal slip for the respective situation; and applying a torque to the wheel in order to adjust the speed or get out of the non-optimal slip again.

8. The method as claimed in claim 7, wherein a comparison of the speed of the at least one wheel is carried out in conjunction with additional sensors, wherein it is ascertained from a current velocity and the speed of the wheel whether the respective wheel has the currently optimal speed.

9. The method as claimed in claim 7, wherein the comparison of the speed of the at least one wheel is carried out in conjunction with a modeling of an optimal speed determined from the currently expected slip.

10. The method as claimed in claim 7, wherein a locked wheel is subjected to a torque during an active ABS system.

11. The power transmission system as claimed in claim 2, wherein the power transmission system comprises an acquisition unit which is configured to acquire a power transmission or a slip of the at least one wheel on a roadway.

12. The power transmission system as claimed in claim 2, wherein the power transmission system comprises an ascertainment unit which is configured to ascertain a need to provide a drive torque.

13. The power transmission system as claimed in claim 3, wherein the power transmission system comprises an ascertainment unit which is configured to ascertain a need to provide a drive torque.

14. The power transmission system as claimed in claim 2, wherein the power transmission system comprises at least one additional sensor which configured to acquire at least one further measured value, wherein the power transmission system comprises a determination unit, which is configured to compare a speed of the at least one wheel in consideration of the at least one further measured value.

15. The power transmission system as claimed in claim 3, wherein the power transmission system comprises at least one additional sensor which configured to acquire at least one further measured value, wherein the power transmission system comprises a determination unit, which is configured to compare a speed of the at least one wheel in consideration of the at least one further measured value.

16. The power transmission system as claimed in claim 4, wherein the power transmission system comprises at least one additional sensor which configured to acquire at least one further measured value, wherein the power transmission system comprises a determination unit, which is configured to compare a speed of the at least one wheel in consideration of the at least one further measured value.

17. The power transmission system as claimed in claim 2, wherein the determination unit is configured to carry out the respective comparison of the speed of the at least one wheel in conjunction with modeling of an optimum speed of the wheel determined from the currently expected slip.

18. The power transmission system as claimed in claim 3, wherein the determination unit is configured to carry out the respective comparison of the speed of the at least one wheel in conjunction with modeling of an optimum speed of the wheel determined from the currently expected slip.

19. The power transmission system as claimed in claim 4, wherein the determination unit is configured to carry out the respective comparison of the speed of the at least one wheel in conjunction with modeling of an optimum speed of the wheel determined from the currently expected slip.

20. The power transmission system as claimed in claim 5, wherein the determination unit is configured to carry out the respective comparison of the speed of the at least one wheel in conjunction with modeling of an optimum speed of the wheel determined from the currently expected slip.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0040] The invention is schematically illustrated in the drawings with the aid of embodiments and is described further with reference to the drawings, wherein the same components are identified by the same reference numerals. In the figures:

[0041] FIG. 1 shows a typical power transmission from a wheel to the roadway,

[0042] FIG. 2 shows a schematic sequence of one embodiment of the method according to the invention for maximizing a power transmission from a wheel to a roadway using one embodiment of a power transmission system according to the invention.

DETAILED DESCRIPTION

[0043] FIG. 1 shows a typical power transmission from a tire or wheel to a roadway. A line diagram of the power transmission is shown. The transmitted power is shown on the Y-axis and the slip is shown in percent on the X-axis.

[0044] A curve profile of the transmittable power or the power transmission as a function of the slip is shown. The curve profile has three subsections A, B, C. During the first subsection there is an increase in the transmittable power with a slight increase in the slip.

[0045] In the event of heavy braking, depending on the braking force and roadway conditions, one or more wheels can temporarily lock or the range of optimal power transmission can be exceeded. In FIG. 1, the subsection B shows the exceeding of the optimal power transmission.

[0046] In order to leave the range of excessive slip with nonoptimal power transmission, the tire or the wheel has to gain rotational velocity. For this purpose, a high energy input is required due to the typically high moment of inertia of the wheel.

[0047] This energy input usually takes place, after the ABS system has opened the brake, due to the friction of the tire on the roadway moving at a higher velocity in relation to the tread or from a drive train or a differential. The component of the friction is low depending on roadway conditions, for example when wet. The available drive torque is thus random to a certain extent.

[0048] Subsection C shows how a drive torque can be deliberately provided. Modern drive concepts, for example hybrid, electric, or electrified vehicles, enable extremely fast provision of a drive torque. In this way, in the event of a heavy braking process, a drive torque can be provided deliberately at the locked or potentially locking wheels, whereby the slip is reduced and an active maximization or increase of the power transmitted by the tire is achieved.

[0049] FIG. 2 shows a schematic sequence of one embodiment of the method according to the invention for maximizing a power transmission from a wheel to a roadway using one embodiment of the power transmission system 10 according to the invention.

[0050] In the method according to the invention, a speed of the at least one wheel is determined in a first step a. In general, the power transmission system comprises at least one sensor which is configured to acquire a speed. In general, a slip of the at least one wheel is determined at the same time.

[0051] In a further step b, a deviation of the present speed from an optimal speed for the respective situation is determined from the determined speed. Alternatively, a deviation of the present slip from an optimal slip for the respective situation is determined. For this purpose, the power transmission system generally has a determination unit which is configured to compare a speed and/or a slip of the at least one wheel.

[0052] In general, the power transmission system comprises at least one additional sensor, wherein the sensor acquires at least one further measured value, for example the vehicle velocity. The determination unit can generally compare the speed of the at least one wheel in consideration of the at least one further measured value, for example the vehicle velocity. The comparison of a respective speed of the respective wheel can alternatively be carried out in conjunction with modeling of an optimal speed determined from the currently expected slip.

[0053] In a further step c, a torque is applied to the wheel in order to adapt the speed or to get out of the non-optimal slip. In one embodiment, the wheel is locked, for example, and has to have a torque applied or has to be accelerated. In an alternative embodiment, a torque is generally applied to the wheel in the event of heavy braking, so that the wheel is automatically acted upon or accelerated as needed by releasing the brake.

[0054] Overall, a torque is thus applied by the power transmission system to a locked wheel during an ABS intervention or an active ABS system. Optionally, the power introduced as torque causes an acceleration. An acceleration is, in this case, a rotation of the wheel resulting from the application of a torque to the wheel. Therefore, in the event of a strong braking process, a drive torque is provided deliberately in the locked or potentially locking wheels, whereby the slip is reduced and an active maximization or increase of the power transmittable by the tire is achieved.

LIST OF REFERENCE NUMERALS

[0055] A first subsection [0056] B further subsection [0057] C further subsection [0058] a first step [0059] b further step [0060] c further step [0061] d further step