Description:TORQUE STEER COMPENSATION IN FRONT-WHEEL DRIVE VEHICLES

TECHNICAL FIELD
[0001] The present disclosure relates to a torque steer compensation method using an Electronic Stability Control (ESC) system in front-wheel drive vehicles.

BACKGROUND
[0002] Front-wheel drive (FWD) vehicles are popular for their cost-effectiveness and efficient use of space, making them a common choice for many car manufacturers. However, one of the challenges associated with FWD vehicles, especially high-performance ones, is torque steer. Torque steer is a phenomenon where the vehicle pulls to one side during acceleration, primarily due to the unequal length of the drive shafts. This can lead to a less stable driving experience and requires constant steering corrections by the driver, which can be particularly problematic in high-performance scenarios where precision and control are paramount.

[0003] To address these challenges, automotive engineers have been exploring various methods to mitigate torque steer. Traditional solutions often involve mechanical adjustments or enhancements to the steering system, e.g. additional torque steer compensation feature in EPAS system, and using equal-length drive shafts or modifying the suspension geometry. However, these solutions can be costly and may not be feasible for all vehicle designs. As a result, there is a growing interest in leveraging electronic systems, such as Electronic Stability Control (ESC), to provide a more adaptable and cost-effective solution. ESC systems are already widely used in vehicles to enhance safety by preventing skids and maintaining vehicle stability, making them a promising platform for implementing torque steer compensation strategies.

SUMMARY
[0004] The method may involve compensating for torque steer in a front-wheel drive vehicle by detecting and counteracting torque steer using an Electronic Stability Control (ESC) system. The ESC system can determine a torque transfer delay in a longer drive shaft of the vehicle. The method may further include selectively applying braking at a shorter shaft wheel for a predetermined time, calculated based on the determined torque transfer delay, to counteract the torque steer.

[0005] Some examples of the method may involve calculating the predetermined time using a Torque Transfer Delay Calculation unit. This unit can determine an angular twist of the longer drive shaft and divide the angular twist by an angular velocity of the longer drive shaft.

[0006] In some examples, the Torque Transfer Delay Calculation unit may use a torsion equation to calculate the angular twist of the longer drive shaft. The torsion equation can be expressed as θ = TL / JG, where T is an applied torque, L is a length of the longer drive shaft, J is a polar moment of inertia, and G is a modulus of rigidity.

[0007] The ESC system may maintain a straight-line trajectory of the vehicle during initial acceleration by selectively applying the braking at the shorter shaft wheel.

[0008] The method can be utilized with a manual rack and pinion steering system.

[0009] The ESC system may comprise a Delay Calculation Unit that calculates the torque transfer delay using angular twist and angular velocity of the longer drive shaft.

[0010] The Delay Calculation Unit can determine a selective braking time for the shorter shaft wheel based on the calculated torque transfer delay.

[0011] Torque steer compensation may be achieved by the ESC system without modifying an existing steering system of the vehicle.

Brief Description Of Drawings
FIG. 1 The diagram shows a torque steer compensation system using an ESC unit in a front-wheel drive vehicle, highlighting key components like the brakes, drive shafts, and steering wheel.

FIG. 2 is a block diagram showing a torque steer compensation method using an ESC system, highlighting components like drive shafts, torque transfer delay, and selective wheel braking signal.

FIG. 3 illustrates a method for counteracting torque steer using an ESC system without modifying the vehicle's steering.

DETAILED DESCRIPTION
[0012] The disclosure provides a method for compensating torque steer in front-wheel drive vehicles using an Electronic Stability Control (ESC) system. The ESC system may detect and counteract torque steer caused by uneven drive shaft lengths. The method can involve selectively applying braking at the shorter shaft wheel for a predetermined time, calculated based on the torque transfer delay in the longer drive shaft. This delay may be determined using a Torque Transfer Delay Calculation unit, which can calculate the angular twist of the longer drive shaft and divide it by the angular velocity of the shaft. The ESC system may maintain a straight-line trajectory of the vehicle during initial acceleration by applying wheel-level braking at shorter shaft wheel. The method can be utilized with manual rack and pinion steering systems, providing a solution without modifying existing steering systems. Unlike conventional EPAS-based compensation, which lacks high accuracy due to the inherent rigidity of the steering system, this approach enhances steering precision by compensating for torque steer at the wheel level through controlled braking. This makes it a more effective and precise alternative for mitigating torque steer in vehicles.

[0013] The block diagram in FIG. 1 illustrates a torque steer compensation system for a front-wheel drive vehicle, utilizing an Electronic Stability Control (ESC) unit. This system is designed to detect and counteract torque steer, a common issue in front-wheel drive vehicles caused by uneven drive shaft lengths. The diagram highlights key components such as the Left-Hand (LH) Brake(1) and Right-Hand (RH) Brake (2), which are connected to the Longer Shaft (3) and Shorter Shaft (4) respectively. These components are integral to the vehicle's drive system (7), with the longer shaft typically experiencing a torque transfer delay due to its length.

[0014] Central to the system is the ESC Unit (9), which processes inputs from various sources, including the Left-Hand (LH) Wheel Speed Sensor (5), Right-Hand (RH) Wheel Speed Sensor (6), Steering Wheel (8), the Acceleration Signal (11), and Motor Control Unit (10). The ESC unit is responsible for calculating torque delay transfer and applying selective braking to counteract torque steer. The Wheel Speed Sensors (WSS) (5,6) provide real-time feedback to the ESC unit, allowing it to make precise adjustments to maintain a straight-line trajectory during initial acceleration. This is achieved by selectively applying braking at the wheel connected to the shorter shaft, compensating for the torque transfer delay experienced by the wheel on the longer shaft, calculated using the Torque Transfer Delay Calculation method.

[0015] The system's functionality is further enhanced by the integration of a Torque Transfer Delay Calculation unit, which determines the angular twist of the longer drive shaft. This calculation is crucial for determining the predetermined braking time, ensuring that the ESC system can effectively counteract torque steer without modifying the existing steering system. The torsion equation, expressed as θ = TL / JG, is used to calculate the angular twist, which is then divided by the shaft's angular velocity to determine the delay time. This precise calculation allows the ESC system to apply wheel-level braking with enhanced precision, overcoming the limitations of traditional EPAS-based compensation methods.

[0016] In summary, the diagram provides an overview of a torque steer compensation system that leverages the capabilities of an ESC unit to maintain vehicle stability and control. By utilizing real-time data from wheel speed sensors and applying calculated braking forces, the system effectively mitigates the effects of torque steer, ensuring a smoother and more controlled driving experience.

[0017] The block diagram in FIG. 2 illustrates a method for compensating torque steer in a front-wheel drive vehicle using an Electronic Stability Control (ESC) system. This diagram is central to understanding how the ESC system can effectively manage torque steer by utilizing various components and calculations. The physical properties such as length, diameter, and material of Longer Drive Shaft (100) and Shorter Drive Shaft (102) are depicted as key elements in determining the Torque Transfer Delay (104) in longer shaft. The ESC System (106) is the core component that enables Selective Braking (108) at the shorter shaft wheel, which is crucial for counteracting torque steer. This selective braking is applied for a predetermined time, calculated based on the torque transfer delay, ensuring precise compensation.

[0018] The Angular Twist (110) and Torque Transfer Delay Calculation (112) are essential for determining the delay time. The Torque Transfer Delay Calculation involves using a torsion equation to calculate the angular twist of the longer drive shaft. This twist is then divided by the shaft's angular velocity to determine the delay time, which is critical for the ESC system to apply the correct amount of braking at the shorter shaft wheel. The method described in the diagram emphasizes the use of the ESC system to maintain a straight-line trajectory during initial acceleration by compensating for torque steer without modifying the existing steering system.

[0019] The structural relationships among the components are clearly defined. The Longer Drive Shaft (100) and Shorter Drive Shaft (102) are positioned to highlight their roles in the torque transfer process. The ESC System (106) is interconnected with these shafts to facilitate the selective braking mechanism. The Torque Transfer Delay (104) and its calculation (112) are integrated into the system to ensure that the braking is applied accurately and effectively. This interaction between components allows the ESC system to achieve the desired torque steer compensation, enhancing the vehicle's performance and stability.

[0020] FIG. 3 is a flowchart illustrating a method in step 300 for compensating torque steer in a front-wheel drive vehicle using an Electronic Stability Control (ESC) system, according to an embodiment. At step 300, the ESC system may be employed to detect and counteract torque steer, which can be caused by uneven drive shaft lengths. The ESC system may determine a torque transfer delay in the longer drive shaft, which may be crucial for calculating the appropriate braking time. The method may involve selectively applying braking at the shorter shaft wheel for a predetermined time to counteract the torque steer. This predetermined time may be calculated based on the determined torque transfer delay, which may involve the use of a Torque Transfer Delay Calculation unit. This unit may determine the angular twist of the longer drive shaft and divide it by the angular velocity of the shaft to calculate the delay. The torsion equation may be used to calculate the angular twist, expressed as θ = TL / JG, where T is the applied torque, L is the length of the shaft, J is the polar moment of inertia, and G is the modulus of rigidity. The ESC system may maintain a straight-line trajectory of the vehicle during initial acceleration by applying the calculated braking at the shorter shaft wheel for a predetermined time. The method may be utilized with a manual rack and pinion steering system, ensuring compatibility with existing systems without requiring modifications. The ESC system may achieve torque steer compensation by applying wheel-level braking, which may enhance precision and maintain a straight-line trajectory during initial acceleration.

[0021] At step 302, the determination of a torque transfer delay in a longer drive shaft of the vehicle may be executed using the Electronic Stability Control (ESC) system. This process may involve the ESC system identifying the time it takes for torque to transfer along the longer drive shaft, which can be crucial for compensating torque steer. The ESC system may utilize a Torque Transfer Delay Calculation unit to ascertain this delay. The calculation may involve determining the angular twist of the longer drive shaft and dividing this twist by the angular velocity of the shaft. The torsion equation, expressed as θ = TL / JG, where T represents the applied torque, L is the length of the longer drive shaft, J is the polar moment of inertia, and G is the modulus of rigidity, may be employed to calculate the angular twist. This calculated angular twist may then be divided by the shaft's angular velocity to determine the torque transfer delay time. This delay time may be essential for the ESC system to apply selective braking at the shorter shaft wheel, ensuring that the torque steer is effectively counteracted. The ESC system's ability to determine and utilize the torque transfer delay may enhance the vehicle's stability and control, particularly during initial acceleration.

[0022] In step 304, the process may involve the selective application of braking at the shorter shaft wheel for a predetermined time using the Electronic Stability Control (ESC) system to counteract torque steer. This action may be crucial in managing the torque steer that can occur in front-wheel drive vehicles due to uneven drive shaft lengths. The predetermined time for braking may be calculated based on the determined torque transfer delay in longer shaft, which is a critical factor in ensuring effective torque steer compensation. The Torque Transfer Delay Calculation unit may play a pivotal role in this process by determining the angular twist of the longer drive shaft and dividing this angular twist by the angular velocity of the longer drive shaft. This calculation may provide the necessary data to establish the appropriate braking time. The torsion equation, expressed as θ = TL / JG, where T is the applied torque, L is the length of the longer drive shaft, J is the polar moment of inertia, and G is the modulus of rigidity, may be utilized by the Torque Transfer Delay Calculation unit to calculate the angular twist of the longer drive shaft. This calculated angular twist may then be divided by the shaft's angular velocity to determine the torque transfer delay time. The ESC system may use this delay time to apply braking at the shorter shaft wheel until the torque effectively reaches the longer shaft wheel, thereby counteracting the torque steer. This method may enhance the vehicle's ability to maintain a straight-line trajectory during initial acceleration, providing a more stable and controlled driving experience. The integration of the Torque Transfer Delay Calculation unit within the ESC system may allow for precise and timely braking interventions, which may be essential for the effective compensation of torque steer without the need for modifications to the existing steering system.

[0023] In step 306, the focus is on the potential role of the Electronic Stability Control (ESC) system in maintaining a straight-line trajectory of a front-wheel drive vehicle during initial acceleration. This may be achieved by selectively applying braking at the shorter shaft wheel. The ESC system may be designed to detect any deviation from the intended path and apply corrective measures to ensure the vehicle remains on course. The selective braking at the shorter shaft wheel may be an action in counteracting the effects of torque steer, which can cause the vehicle to veer off its intended path. The ESC system may utilize data from various sensors to determine the appropriate timing and intensity of the braking action to maintain stability and control. This process may involve calculating the torque transfer delay, which is the time it takes for torque to be transferred from the engine to the wheels, and using this information to time the braking action precisely. The ESC system may also consider factors such as the angular twist of the longer drive shaft and its angular velocity to optimize the braking strategy. By doing so, the ESC system may enhance the vehicle's ability to maintain a straight-line trajectory, thereby improving safety and performance during acceleration. This approach may offer a more precise and effective solution compared to traditional methods, which may rely on modifications to the steering system. The use of the ESC system in this manner may provide a seamless integration with existing vehicle systems, allowing for torque steer compensation without the need for extensive modifications.

[0024] The method may be utilized with a manual rack and pinion steering system. The ESC system may comprise a Delay Calculation Unit that calculates the torque transfer delay using the angular twist and angular velocity of the longer drive shaft. The Delay Calculation Unit may determine a selective braking time for the shorter shaft wheel based on the calculated torque transfer delay. The manual rack and pinion steering system may be compatible with the method, providing a solution without requiring modifications to the existing steering system. The ESC system may enhance the vehicle's ability to maintain a straight-line trajectory during initial acceleration by applying wheel-level braking via the ESC unit. The torque transfer delay may be crucial for compensating torque steer, and the selective braking at the shorter shaft wheel may counteract torque steer caused by uneven drive shaft lengths. The method may overcome the accuracy limitations of EPAS-based compensation, enhancing precision in steering. The ESC system may stabilize the vehicle during acceleration, ensuring compatibility with existing systems and providing a comprehensive solution for torque steer compensation in front-wheel drive vehicles.

[0025] The torque steer compensation may be achieved by the Electronic Stability Control (ESC) system without necessitating modifications to the existing steering system of the vehicle. This process may involve the ESC system detecting and counteracting torque steer, which can be a result of uneven drive shaft lengths in a front-wheel drive vehicle. The ESC system may selectively apply braking at the shorter shaft wheel for a predetermined time, calculated based on the torque transfer delay. This delay may be determined by the Torque Transfer Delay Calculation unit, which may calculate the angular twist of the longer drive shaft and divide it by the angular velocity of the shaft. The torsion equation may be employed to calculate the angular twist, expressed as θ = TL / JG, where T represents the applied torque, L is the length of the shaft, J is the polar moment of inertia, and G is the modulus of rigidity. The calculated torque transfer delay may then inform the selective braking time for the shorter shaft wheel, ensuring that the torque steer is effectively counteracted. This method may allow the vehicle to maintain a straight-line trajectory during initial acceleration, enhancing the precision of the steering without altering the existing steering system. The ESC system's ability to achieve torque steer compensation without modifying the steering system may provide compatibility with existing systems, offering a solution for front-wheel drive vehicles. , Claims:I/We CLAIM:
1. A method for compensating torque steer in a front-wheel drive vehicle, the method comprising:
detecting and counteracting torque steer using an Electronic Stability Control (ESC) system,
determining a torque transfer delay in a longer drive shaft of the vehicle using the ESC system,
characterized in that the method further comprises:
selectively applying braking at a shorter shaft wheel for a predetermined time using the ESC system to counteract the torque steer, wherein the predetermined time is calculated based on the determined torque transfer delay.
2. The method according to claim 1, wherein the predetermined time is calculated using a Torque Transfer Delay Calculation unit that determines an angular twist of the longer drive shaft and divides the angular twist by an angular velocity of the longer drive shaft.

3. The method according to claim 2, wherein the Torque Transfer Delay Calculation unit uses a torsion equation to calculate the angular twist of the longer drive shaft, the torsion equation expressed as: θ = TL / JG, where T is an applied torque, L is a length of the longer drive shaft, J is a polar moment of inertia, and G is a modulus of rigidity.

4. The method according to claim 1, wherein the ESC system maintains a straight-line trajectory of the vehicle during initial acceleration by selectively applying the braking at the shorter shaft wheel.
5. The method according to claim 1, wherein the method is utilized with a manual rack and pinion steering system.

6. The method according to claim 1, wherein the ESC system comprises a Delay Calculation Unit that calculates the torque transfer delay using angular twist, and angular velocity of the longer drive shaft.

7. The method according to claim 6, wherein the Delay Calculation Unit determines a selective braking time for the shorter shaft wheel based on the calculated torque transfer delay.

8. The method according to claim 1, wherein the torque steer compensation is achieved by the ESC system without modifying an existing steering system of the vehicle.