Control unit in vehicle for adjusting torque during wheel slip

Abstract

The invention relates to a control unit in a vehicle for adjusting torque during wheel slip. A control unit (10) detects a wheel (11) slip based on a change in a vehicle parameter and activates a traction control module (14) to calculate and reduce a demand torque during a wheel slip moment. A control unit (10) calculates a target torque from a plurality of vehicle parameters and, after comparing the target torque with a demand torque, supplies it as a desired torque from an inverter unit (16). The control unit (10) adjusts the desired torque in sequential steps by controlling the desired phase current generated by the inverter unit (16).

Description

Technical Field

[0001] The invention relates to a control unit in a vehicle for regulating torque during wheel slip. Background Art

[0002] In some electric motorcycles used for on- and off-road use, hazards such as loss of traction and unintended vehicle acceleration and deceleration are assessed at ASIL (Automotive Safety Integrity Level) levels according to the ISO 26262 functional safety standard. Monitoring the torque delivered to the wheels is necessary to mitigate these hazards. The current concept simplifies traction control torque monitoring by monitoring its maximum and minimum values, as well as its gradient. This prevents unintended vehicle acceleration and deceleration when traction control is engaged.

[0003] Patent application US20090132123 discloses a vehicle wheel slip control device, which reduces engine torque to prevent wheel slip when wheel slip is determined to have occurred, including: detecting driving control information and information about the vehicle state, and determining whether basic conditions required to perform engine torque limit control to prevent wheel slip are met; when the basic conditions are met, calculating speed change and speed gradient value, and comparing the speed gradient value with a predetermined speed gradient value to determine whether slip has occurred; when slip is determined to have occurred, performing engine torque limit control using a torque gradient map set according to the current engine torque; and when the vehicle speed is reduced by the engine torque limit control and the cancellation condition is met, canceling the engine torque limit control and returning to normal control. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 A control unit for regulating torque during wheel slip in a vehicle according to one embodiment of the present invention is illustrated; and

[0005] Figure 2 A flow chart of a method for regulating torque according to the present invention is illustrated. DETAILED DESCRIPTION

[0006] Figure 1 The diagram illustrates a control unit for performing component-related tasks according to one embodiment of the present invention. The control unit 10 detects wheel 11 slip based on changes in vehicle parameters and activates the traction control module 14 to calculate and reduce the required torque during moments of wheel slip. The control unit 10 calculates a target torque based on multiple vehicle parameters and, after comparing the target torque with the required torque, provides the target torque as a desired torque from the inverter unit 16. The control unit 10 adjusts the desired torque in sequential steps by controlling the required phase currents generated by the inverter unit 16.

[0007] In addition, the construction of the control unit 10 and the components associated with the control unit 10 are explained in detail. The control unit 10 is a logic circuit and software program implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits and / or any components that operate on signals based on operating instructions. The vehicle parameters are selected from a group of vehicle parameters including the electric motor speed gradient (RPM / second), throttle grip position, motor speed (RPM), and RPM gradient. However, it should be understood that the vehicle parameters can be any other parameters known in the prior art. The control unit 10 includes a memory 22 that stores multiple target torques mapped to corresponding multiple rider demand torques. In real time, the control unit 10 provides the desired torque from the inverter unit 16 by selecting any rider demand torque mapped to the calculated target torque.

[0008] The inverter unit 16 supplies the required phase current to the electric motor 18 of the vehicle 12 to generate the desired torque. The control unit 10 continuously monitors the gradual increase in the desired torque and maintains the desired torque within predetermined limits. During a fault, the control unit 10 identifies the fault when it senses that the desired torque exceeds the predetermined limit. The torque limit module 20 of the control unit 10 is activated upon detecting the fault to maintain a safe torque limit.

[0009] Figure 2 A flowchart of a method for adjusting torque according to the present invention is shown. In step S1, wheel 11 slip is detected based on changes in vehicle parameters. In step S2, the traction control module 14 is activated to calculate and reduce the required torque during the moment of wheel 11 slip. In step S3, a target torque is calculated based on multiple vehicle parameters, and after comparing this target torque with the required torque, it is provided as the desired torque from the inverter unit 16. In step S4, the desired torque is adjusted in sequential steps by controlling the required phase current generated by the inverter unit 16.

[0010] The method is explained in detail. The control unit 10 activates the traction control module 14 when it detects a change in any vehicle parameter that results in a wheel slip condition. One such parameter in the present invention is the electric motor speed gradient (RPM per second). When the traction control module 14 is activated, the rider demands a torque reduction to prevent the wheels 11 from slipping. The traction control module 14 calculates a target torque to be reduced. When the traction control module 14 is activated, the control unit 10 monitors the target torque reduction by monitoring its torque gradient (Nm per second) and its minimum value. The target torque reduction is always lower than the rider demand torque and the minimum value. A faster target torque reduction that exceeds the minimum value will result in an unintended deceleration of the vehicle 12.

[0011] This target torque is coordinated with the rider's requested torque, and the request is sent to the inverter unit. The requested torque, known as the desired torque, is the output of the inverter unit. The desired torque is derived from the rider's requested torque and the target torque, and the inverter unit generates the necessary phase currents to the electric motor to produce the desired torque consistent with the rider's requested torque. When the traction control module is deactivated, the target torque is ramped up to the rider's requested torque, and a faster ramp up, exceeding the rider's requested torque, would result in uncontrollable acceleration.

[0012] The control unit 10 monitors the desired torque and maintains a sequential increase in torque rather than a sudden increase in the desired torque. The control unit 10 detects a fault in at least one component of the vehicle 12 and senses the sudden torque jump caused by the fault. Upon detecting the fault, the control unit 10 requests the inverter unit 16 to maintain a safe torque (in this case, the desired torque). The control unit 10 calculates the permitted torque based on an independent and redundant calculation of the rider's demand torque with an added tolerance.

[0013] It should be understood that the embodiments explained in the above description are merely illustrative and do not limit the scope of the present invention. Many such embodiments and other modifications and variations of the embodiments explained in the description are contemplated. The scope of the present invention is limited only by the scope of the claims.

Claims

1. A control unit (10) for regulating torque during wheel (11) slip in a vehicle (12), the control unit (10) being adapted to: - detecting wheel (11) slip based on changes in vehicle parameters; - activating a traction control module (14) to calculate a required torque during the wheel slip moment and to reduce the required torque; - calculating a target torque based on a plurality of vehicle parameters and providing the target torque as a desired torque from an inverter unit (16) after comparing the target torque with the required torque; - regulating the desired torque in sequential steps by controlling the required phase currents generated by the inverter unit (16).

2. The control unit (10) according to claim 1, wherein The vehicle parameter is selected from a group of vehicle parameters including electric motor speed gradient (RPM / second), throttle grip position, motor speed (RPM), and RPM gradient.

3. The control unit (10) according to claim 1, wherein The calculated target torque is mapped to the rider demand torque, and the calculated target torque is provided as a desired torque from the inverter unit (16).

4. The control unit (10) according to claim 1, wherein The inverter unit (16) is adapted to provide the required phase current to the electric motor (18) of the vehicle to generate the desired torque.

5. The control unit (10) according to claim 1, wherein the control unit (10) continuously monitors the gradual increase of the desired torque and maintains the desired torque within predetermined limits.

6. The control unit (10) according to claim 1, wherein The control unit (10) is adapted to detect a fault upon sensing that the desired torque exceeds the predetermined limit.

7. The control unit (10) according to claim 6, wherein When a fault is detected, the torque limit module (20) is enabled to maintain a safe limit torque.

8. A method of regulating torque during wheel (11) slip in a vehicle (12), the method comprising: - detecting wheel (11) slip by a control unit (10) based on changes in vehicle parameters; - activating a traction control module (14) to calculate a required torque during the wheel slip moment and to reduce the required torque; - calculating a target torque based on a plurality of vehicle parameters and providing the target torque as a desired torque from an inverter unit (16) after comparing the target torque with the required torque; - regulating the desired torque in sequential steps by controlling the required phase currents generated by the inverter unit (16).

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