KR-102962204-B1 - PARKING BRAKE FAIL SAFETY CONTROL SYSTEM FOR VEHICLE HAVING ELECTRIC-AXLE AND METHOD THEREOF

KR102962204B1KR 102962204 B1KR102962204 B1KR 102962204B1KR-102962204-B1

Abstract

The present invention aims to provide a parking brake fail safety control system and method for a commercial vehicle having an electrified axle, wherein, in the event of a parking brake failure, the torque of a first motor included in a first rear electrified axle and the torque of a second motor included in a second rear electrified axle are controlled to be equal in magnitude and in opposite directions, and the torque of the first motor or the second motor is controlled to increase or decrease according to changes in wheel speed, thereby enabling safe parking braking on flat roads and slopes.

Inventors

오준

Assignees

현대자동차주식회사
기아 주식회사

Dates

Publication Date: 20260508
Application Date: 20210316

Claims (14)

A parking brake switch for a commercial vehicle to be turned on by the driver; A wheel speed sensor for detecting changes in wheel speed of the above commercial vehicle; A first motor included in the first rear-wheel electrified axle of the above commercial vehicle; A second motor included in the second electric axle of the rear wheel of the above commercial vehicle; and A controller that, after receiving an ON signal from the parking brake switch, receives a signal from the wheel speed sensor and, if it is confirmed that there is a change in wheel speed, determines that the parking brake has failed and controls the torque of the first motor and the torque of the second motor in opposite directions with equal magnitudes; A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized by being composed including
In claim 1, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized by further including a door open detection sensor to determine whether the parking brake has failed in the controller above.
In claim 2, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized in that the controller is configured to receive an opening signal from the door opening detection sensor, and then receive a signal from the wheel speed sensor and, if it is confirmed that there is a change in wheel speed, determine that the parking brake has failed, and control the torque of the first motor and the torque of the second motor in opposite directions with equal magnitudes.
In claim 1, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized by further including a longitudinal acceleration sensor for determining whether the vehicle is on an uphill road with a (+) slope or a downhill road with a (-) slope after the torque of the first motor and the torque of the second motor are controlled in opposite directions and of equal magnitude in the controller above, and if the wheel speed change continues.
In claim 4, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized in that the controller is configured to receive a signal from the longitudinal acceleration sensor and, when it is confirmed to be an uphill road, to control the torque of the first motor to decrease until the wheel speed becomes zero if the wheel speed is greater than zero, and to control the torque of the first motor to increase until the wheel speed becomes zero if the wheel speed is less than zero.
In claim 4, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized in that the controller is configured to receive a signal from the longitudinal acceleration sensor and, when it is confirmed to be a downhill slope, to control the torque of the second motor to increase until the wheel speed becomes zero if the wheel speed is greater than zero, and to control the torque of the second motor to decrease until the wheel speed becomes zero if the wheel speed is less than zero.
In claim 4, A parking brake fail safety control system for a commercial vehicle having an electrified axle, characterized in that the controller is configured to receive a signal from the longitudinal acceleration sensor and, even though it is confirmed that the vehicle is not on an uphill or downhill slope, to control the torque of the first motor until the wheel speed becomes zero when the wheel speed is greater than zero, and to control the torque of the second motor until the wheel speed becomes zero when the wheel speed is less than zero.
ON stage of the parking brake switch of a commercial vehicle by driver operation; A step of determining whether the parking brake of the above commercial vehicle has failed; If it is determined that the above parking brake has failed, the controller controls the torque of the first motor included in the first rear-wheel electrified axle of the commercial vehicle and the torque of the second motor included in the second rear-wheel electrified axle in opposite directions and of equal magnitude; A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized by including
In claim 8, The step of determining whether the above parking brake has failed is: A step for detecting wheel speed by a wheel speed sensor; A step of checking whether there is a change in wheel speed based on the detection signal of the wheel speed sensor after receiving the ON signal of the parking brake switch in the controller; A step of determining that the parking brake has failed if there is a change in the wheel speed mentioned above; Parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized by comprising
In claim 8, The step of determining whether the above parking brake has failed is: A step of detecting whether the door is open using a door open detection sensor; A step for detecting wheel speed by a wheel speed sensor; A step of receiving a door opening signal from the door opening detection sensor in the controller, and then checking whether there is a change in wheel speed based on the detection signal of the wheel speed sensor; A step of determining that the parking brake has failed if there is a change in the wheel speed mentioned above; A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized by being composed of
In claim 8, A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized by further including the step of, after controlling the torque of the first motor and the torque of the second motor in the above controller to be equal in magnitude and opposite to each other, determining whether the vehicle is on an uphill road with a (+) slope or a downhill road with a (-) slope if the wheel speed change continues.
In claim 11, A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized in that when it is confirmed that the vehicle is on an uphill road, if the wheel speed is greater than 0, control is performed to reduce the torque of the first motor until the wheel speed becomes zero, and if the wheel speed is less than 0, control is performed to increase the torque of the first motor until the wheel speed becomes zero.
In claim 11, A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized in that when it is confirmed that the vehicle is on a downhill slope, if the wheel speed is greater than 0, control is performed to increase the torque of the second motor until the wheel speed becomes zero, and if the wheel speed is less than 0, control is performed to decrease the torque of the second motor until the wheel speed becomes zero.
In claim 11, A parking brake fail safety control method for a commercial vehicle having an electrified axle, characterized in that, even though it is confirmed that the road is not an uphill or downhill, control is performed to reduce the torque of the first motor until the wheel speed becomes zero when the wheel speed is greater than zero, and control is performed to reduce the torque of the second motor until the wheel speed becomes zero when the wheel speed is less than zero.

Description

Parking Brake Failure Safety Control System and Method for Commercial Vehicle Having an Electric Axle The present invention relates to a parking brake fail safety control system and method for a commercial vehicle having an electrified axle, and more specifically, to a parking brake fail safety control system and method for a commercial vehicle having an electrified axle that enables safe parking braking through motor torque control of the electrified axle in the event of a parking brake failure. With the launch of eco-friendly passenger vehicles such as electric vehicles and hydrogen fuel cell vehicles, pure electric trucks or hydrogen fuel cell trucks equipped with electric axle assemblies are being developed as a type of eco-friendly commercial vehicle. It is desirable that commercial vehicles equipped with such electrified axles be developed to a level that meets both the driving and braking performance standards of existing commercial vehicles equipped with diesel engines. For example, existing diesel engine trucks have a unique feature called Parking Brake Fail Safety, which allows the vehicle's movement to be restricted as if the parking brake were engaged in the event of a failure; this Parking Brake Fail Safety feature must also be included in commercial vehicles equipped with electrified axles. The parking brake fail safety function of the above-mentioned diesel engine truck is one of the functions of the automatic transmission, and refers to a function that, in the event that the parking brake of the diesel engine truck fails or unintentional vehicle rollback is detected while the gear is in N, restrains each preset component of a plurality of planetary gear sets included in the automatic transmission with clutch and brake elements, thereby making the speed of the output shaft of the automatic transmission zero (0) so that the vehicle does not move. While the parking brake fail safety function of such diesel engine trucks can be implemented through the presence of an automatic transmission mounted on the engine's output shaft, commercial vehicles with electrified axles require a parking brake fail safety function that can be implemented in a different way due to the use of motor and reduction gear power. To elaborate, considering that commercial vehicles equipped with electrified axles must be developed to meet the driving and braking performance requirements of commercial vehicles equipped with conventional diesel engines, parking brake fail safety features must also be included in commercial vehicles equipped with electrified axles. FIG. 1 is a schematic diagram illustrating the powertrain of a hydrogen fuel cell truck among commercial vehicles having an electrified axle. FIG. 2 is a configuration diagram illustrating a parking brake fail safety control system for a commercial vehicle having an electrified axle according to the present invention. FIG. 3 is a graph illustrating an example of motor torque control for parking brake fail safety of a commercial vehicle having an electrified axle according to the present invention. FIGS. 4 and 5 are flowcharts illustrating a parking brake fail safety control method for a commercial vehicle having an electrified axle according to the present invention. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 attached is a schematic diagram illustrating the powertrain of a hydrogen fuel cell truck among commercial vehicles having an electrified axle. As illustrated in FIG. 1, a hydrogen fuel cell truck among commercial vehicles having an electrified axle includes a fuel cell (30) that generates electric energy and a battery (40) in which the electric energy generated from the fuel cell (30) is charged. In addition, the hydrogen fuel cell truck has a structure in which, in addition to the front wheel positioned at the front, a pair of rear wheels serving as driving wheels are arranged at the rear, and among the pair of rear wheels, a first electrified axle (10) is mounted on the front rear wheel and a second electrified axle (20) is mounted on the rear rear wheel. The above-mentioned rear first electric axle (10) may be configured to include an axle housing, a first motor (11) mounted within the axle housing and driven by electrical energy from a fuel cell (30) or a battery (40), a first axle shaft (12) connected to the output shaft of the first motor (11), and a first wheel (13) mounted on both ends of the first axle shaft (12). The above-mentioned second electric axle (20) may also be configured to include an axle housing, a second motor (21) mounted within the axle housing and driven by electrical energy from a fuel cell (30) or a battery (40), a second axle shaft (22) connected to the output shaft of the second motor (21), and second wheels (23) mounted on both ends of the second axle shaft (22). At this time, a reduction gear (not shown) may be connected to the out