Electric vehicle (EV) system

Abstract

The disclosure relates to an electric vehicle (EV) system. An electric vehicle system includes an electric drive axle including a first electric motor configured to transfer mechanical power to a first drive wheel; a second electric motor configured to transmit mechanical power to the second drive wheel; and a motor coupling clutch configured to selectively rotationally couple the first motor to the second motor. The electric vehicle system also includes a controller configured to selectively rotationally couple the first electric machine to the second electric machine through operation of the motor coupling clutch depending on a vehicle load.

Description

Technical Field

[0001] The present disclosure relates to an electric vehicle (EV) system that includes an electric motor coupling clutch for selectively rotationally coupling an electric motor in a drive axle assembly. Background Art

[0002] Electric vehicles (EVs), such as battery electric vehicles, are becoming increasingly popular in the market due to reasons such as no tailpipe emissions. In some electric vehicle platforms, a power drive unit with multiple electric motors is used, where each electric motor is paired with a separate drive wheel, and traction performance can be improved by independent control of the electric motors. Compared with a power drive system with an electric motor remote from the drive axle assembly, an electric drive axle can be more effectively integrated into the vehicle platform and is thus used in some vehicles. However, some electric vehicles may exhibit problems of low powertrain efficiency under certain operating conditions. For example, the inventors unexpectedly found that when multiple electric motors are used in a drive axle, under certain operating conditions, especially in vehicles with a large payload variation during vehicle operation, dual-motor operation may be inefficient.

[0003] The present inventors recognized the above problems in conventional electric power systems and developed an electric vehicle system. In one example, the electric vehicle system includes an electric drive axle having a first electric motor configured to transmit mechanical power to a first drive wheel and a second electric motor configured to transmit mechanical power to a second drive wheel. The electric drive axle further includes an electric motor coupling clutch configured to selectively rotationally couple the first electric motor and the second electric motor. The electric drive axle even further includes a controller configured to selectively rotationally couple the first electric motor to the second electric motor by operating the electric motor coupling clutch according to the vehicle load. Controlling the electric motor coupling clutch according to the vehicle load can improve the efficiency of the power transmission system. In addition, when one electric motor or related electronic hardware fails, the vehicle can still continue to operate.

[0004] Further, in one example, selectively rotationally coupling the first electric motor to the second electric motor may include rotationally coupling the first electric motor to the second electric motor in response to the vehicle load decreasing below a threshold. In such an example, the controller may be further configured to operate the first electric motor to provide mechanical power to the first and second drive wheels while the second electric motor shuts down in response to the vehicle load decreasing below the threshold and the steering angle being less than a threshold angle. Thus, when the vehicle load decreases and no steering operation is required, the electric drive axle is adjusted to a more efficient configuration. In such an example, the electric drive axle may be arranged below a component (such as a bed, a cargo box, etc.) configured to receive a payload during vehicle operation.

[0005] It should be understood that the above summary is to introduce in a simplified form concepts further described in the detailed description. It is not intended to identify the key or essential features of the claimed subject matter, the scope of which is uniquely determined by the claims that follow the detailed description. Additionally, the claimed subject matter is not limited to embodiments that solve any disadvantages noted above or in any part of this disclosure. Summary of the Invention

[0006] According to one aspect of the present utility model, there is provided an electric vehicle (EV) system, comprising: an electric drive axle, including: a first motor for transmitting mechanical power to a first drive wheel; a second motor for transmitting mechanical power to a second drive wheel; a motor coupling clutch that selectively rotationally couples the first motor and the second motor; and a controller that contains instructions which, when executed, cause the controller to: selectively rotationally couple the first motor to the second motor according to the vehicle load by operation of the motor coupling clutch.

[0007] The electric vehicle system as described above, wherein selectively rotationally coupling the first motor to the second motor includes rotationally coupling the first motor to the second motor in response to the vehicle load dropping below a threshold vehicle load.

[0008] The electric vehicle system as described in any one of the above, wherein the controller further includes instructions that cause the controller to: maintain rotational decoupling between the first motor and the second motor when the vehicle steering angle exceeds a threshold angle and the vehicle load is below the threshold vehicle load.

[0009] The electric vehicle system as described in any one of the above, wherein selectively rotationally coupling the first motor to the second motor includes rotationally coupling the first motor to the second motor when the steering angle is less than the threshold angle.

[0010] The electric vehicle system as described in any one of the above, wherein the controller further includes instructions that, in response to the vehicle load dropping below the threshold vehicle load and when the steering angle is less than the threshold angle, cause the controller to: operate the first motor to provide mechanical power to the first and second drive wheels when the second motor is turned off.

[0011] The electric vehicle system as described in any one of the above, wherein the electric drive axle is a rear electric drive axle, and the electric vehicle system is included in an electric vehicle, and the position of its payload receiving assembly is adjacent to and / or above the rear electric drive axle.

[0012] The electric vehicle system as described in any one of the above, wherein the motor coupling clutch is a friction clutch.

[0013] The electric vehicle system as described in any one of the above, wherein the friction clutch is hydraulically driven by a hydraulic drive system.

[0014] The electric vehicle system as described in any one of the above, wherein the controller is a motor control unit that communicates electronically with the drive motor in the hydraulic drive system.

[0015] The electric vehicle system as described in any one of the above, wherein the first motor, the second motor, the first drive wheel, and the second drive wheel are coaxially arranged.

[0016] The electric vehicle system as described in any one of the above, wherein the motor coupling clutch is a dog clutch, and wherein the vehicle load is determined based on the torque and speed requirements of the first motor and the second motor; or the vehicle load is determined based on the power consumption of the first motor and the second motor.

[0017] The electric vehicle system as described in any one of the above, wherein the controller further includes instructions that, when the steering angle is greater than a threshold angle, cause the controller to: decouple the rotation of the first motor from the second motor through the operation of the motor coupling clutch; operate the first motor to provide mechanical power to the first drive wheel; and operate the second motor to provide mechanical power to the second drive wheel.

[0018] The electric vehicle system as described in any one of the above, wherein the motor coupling clutch is a hydraulically operated friction clutch. Description of the Drawings

[0019] Figure 1 Shows an example of an electric vehicle (EV) having multiple electric drive shafts.

[0020] Figure 2 Shows an example of a hydraulic circuit for driving a motor coupling clutch in an electric drive axle.

[0021] Figure 3 Shows an example of an electric drive axle.

[0022] Figure 4 What is shown is Figure 3 The electric drive axle shown, with the motor coupling clutch in the disengaged state.

[0023] Figure 5 What is shown is Figure 3 The electric drive axle shown, with the motor coupling clutch engaged.

[0024] Figure 6 And Figure 7 Shows examples of electric vehicles.

[0025] Figure 8 and Figure 9 shows an example of an electric vehicle drivetrain.

[0026] Figure 10 and Figure 11 shows an example of a wheel end assembly for an electric drive axle.

[0027] Figure 12 and Figure 13 shows a table corresponding to an electric powertrain control scheme.

[0028] Figure 14 and Figure 15 shows a method of operating an electric powertrain. DETAILED DESCRIPTION

[0029] This document describes an electric vehicle (EV) system that, in some examples, can change the rotational connection between motors in a drive axle based on vehicle load and steering angle. Specifically, to improve the efficiency of the powertrain, the motor coupling clutches in the drive axle are engaged to rotationally couple the traction motors in the axle and provide power to the drive wheels on both sides of the vehicle, while turning off one of the motors to save energy. The entry conditions for this mode can include the load on the drive axle being below a threshold and the steering angle being below a threshold. Conversely, the exit conditions for the single-motor mode can include the steering angle increasing above the threshold and / or the load on the drive axle increasing above the threshold. Additionally, in some examples, the configuration of the front and rear drive axles can be adjusted based on the load on a particular drive axle and the steering angle of the vehicle.

[0030] Figure 1Shows a schematic diagram of an electric vehicle (EV) 100 with a powertrain 102. The electric vehicle can be a fully electric vehicle, and compared with a hybrid electric vehicle, the complexity and potential component degradation points of a fully electric vehicle may be reduced. However, embodiments of a hybrid electric vehicle (HEV) can also be used when the vehicle includes an internal combustion engine (ICE). In addition, in one example, the vehicle may be an off-highway vehicle, and its size and / or maximum speed may prevent it from traveling on a highway. For example, the vehicle width may be greater than a highway lane, and / or the maximum vehicle speed may be less than the minimum highway speed. However, in other examples, the vehicle can be a highway vehicle such as a commercial vehicle or a passenger vehicle. More specifically, the electric vehicle can be an off-highway vehicle with an articulated frame. In a specific use case, the electric vehicle can be a mining truck (such as an earth hauler) with a dump box for transporting a payload. In another example, the electric vehicle can be a load haul dump truck equipped with a bucket for transporting and dumping a payload. Generally speaking, the electric vehicle can be a medium or heavy-duty vehicle. However, in other examples, the electric vehicle can also be a light-duty vehicle. These specific use cases of electric vehicles will be described in detail in Figure 3-11 which will be elaborated in detail. More generally, the electric vehicle may include a payload receiving assembly 103 (such as a dump box, bed, bucket, etc.), which in one example can be arranged between the electric drive axles, or in other examples, can be arranged near and / or above one of the electric drive axles.

[0031] In the illustrated example, the powertrain 102 includes a first electric drive axle 104 and a second electric drive axle 106. Specifically, in one example, the first electric drive axle can be a front electric drive axle, and the second electric drive axle can be a rear electric drive axle, and in other examples, vice versa. In addition, in other examples, one of the first and second drive axles can be omitted from the powertrain.

[0032] As discussed herein, the numbers associated with each drive axle and other components described herein do not represent any structural or functional hierarchy, but only represent the order in which the drive axles and components are introduced. Therefore, in other examples, the numbers of the drive axles and components can be changed.

[0033] In one example, the first and second electric drive axles 104, 106 can have similar sizes and component structures. However, in other examples, the sizes and / or types of components in the drive axles may vary from one drive axle to another. However, if the sizes of the electric drive axles and the components used are similar (such as having the same size and structure), it can simplify vehicle manufacturing.

[0034] The first electric drive axle 104 includes a first electric motor 108 (e.g., an electric motor / generator) and a second electric motor 110 (e.g., an electric motor / generator). At least some of the other electric motors described herein may also be designed as electric motor / generators to enable the powertrain to perform a regenerative function, where the operation of the electric motor can charge the battery and / or other suitable energy storage devices. The first electric motor 108 is rotationally coupled to one or more drive wheels 112 through a first wheel-end driveline 114, and the second electric motor 110 is rotationally coupled to one or more drive wheels 116 through a second wheel-end driveline 118. The wheel-end driveline system (e.g., the wheel-end driveline hub) may include a shaft, gears (e.g., planetary gear sets), etc., and can deliver mechanical power at the required speed / torque to the corresponding drive wheels. However, in other examples, the electric motor can be directly rotationally coupled to the drive wheels.

[0035] The first electric drive axle 104 further includes a first motor coupling clutch assembly 120 with a motor coupling clutch 121, which is configured to selectively rotationally couple (e.g., rotationally couple and decouple) the rotor shafts of the first and second electric motors 108, 110. Thus, when the clutch is disengaged, the electric motors can rotate independently, and when the clutch is engaged, the electric motors are locked to rotate together. The motor coupling clutch 121 can be a friction clutch, which can vary the torque transmitted through the clutch to achieve smooth engagement and disengagement. However, in other examples, the motor coupling clutch can be a synchronizer.

[0036] The second electric drive axle 106 includes a third electric motor 122, a fourth electric motor 124, a second motor coupling clutch assembly 127, a third wheel-end driveline 128, and a fourth wheel-end driveline 130. The structure and function of these components are similar to the corresponding components in the first electric drive axle 104. The second motor coupling clutch assembly 126 includes a motor coupling clutch 127.

[0037] In one example, the motor-coupled clutches 121 and 127 can be friction clutches (e.g., multi-plate friction clutches). The torque capacity of the clutch can be varied by changing the number of plates within the housing according to the expected torque and speed requirements of a particular vehicle platform. However, in other examples, the motor-coupled clutches can be cone clutches, dog clutches, and spline clutches, as well as combinations thereof, etc. Additionally, in one example, the motor-coupled clutches 121 and 127 can be hydraulically actuated. However, in other examples, the motor-coupled clutches can be mechanically actuated (e.g., by a mechanical lever), electromechanically actuated, pneumatically or vacuum actuated, etc. The electric vehicle 100 can further include an energy storage device system 132 having a high-voltage energy storage device 134 (e.g., a battery, capacitor, fuel cell, combinations thereof, etc.) and a low-voltage energy storage device 136 (e.g., a battery, capacitor, fuel cell, combinations thereof, etc.). In other examples, the electric vehicle can include fewer or more energy storage devices, which may or may not have different voltages. The high-voltage energy storage device 134 can be electrically coupled to the motors 108, 110, 122, 124 through an energy storage device management system 138. The energy storage device management system 138 can be configured to improve the efficiency of the energy storage device and protect the energy storage device from deep discharge and / or overvoltage conditions that may be caused by rapid charge and discharge currents.

[0038] In addition, the energy storage device management system 138 can further be electrically coupled to the motor control units 140, 142, 144, and 146. The motor control units can include inverters configured to convert direct current (DC) electrical energy to alternating current (AC) electrical energy and vice versa. The motor control units 140, 142, 144, and 146 are electrically coupled to the motors 108, 110, 122, and 124, respectively. Thus, the electric motors 108, 110, 122, and 124 can be polyphase AC-type motors, which in some cases are more efficient than other types of motors.

[0039] In other examples, the energy storage device management system 138 can be omitted from the electric vehicle or take other forms. Additionally, in other examples, at least a portion of the motor control unit can be integrated into one or more integrated units, or the motor control unit can be omitted from the electric vehicle. The high-voltage energy storage device 134 can further be electrically coupled to a motor 148 in a clutch drive system 150, which will be discussed in more detail herein.

[0040] The energy storage device management system 138 (e.g., a battery management system) can be configured to manage the amount of electrical energy transfer between the high-voltage energy storage device 134 and the motors 108, 110, 122, 124 (e.g., traction motors) and the motor control units 140, 142, 144, 146 in the illustrated example.

[0041] The electric vehicle 100 may also include a control system 152 that receives sensor inputs and sends control commands to the actuators of the various components of the electric vehicle. The control system 152 may include motor control units 140, 142, 144, and 146. The control system 152 may also include a vehicle control unit (VCU) 154 and a driveline control unit (DCU) 156. However, other control system configurations may also be considered, including additional or alternative control units. For example, two or more control units may be combined into one control unit that incorporates the functions of each unit. The control units described herein are generally controllers with a memory and a processor. The memory stores instructions for performing the different methods, control techniques, etc. described herein.

[0042] It will be appreciated that various electrical connections may be established in the electric powertrain 102 through suitable components such as wires, cables, busbars, combinations thereof, etc. Specifically, the low-voltage energy storage device 136 may be electrically connected to the motor control units 140, 142, 144, 146, VCU 154, DCU 156, and / or various sensors described in more detail herein (such as the steering sensor 158, wheel speed sensors 160, 162, 164, 166, etc.). The high-voltage energy storage device 134 may be electrically connected to the energy storage device management system 138, which may distribute high-voltage electrical energy to the motor control units 140, 142, 144, 146, 172. The VCU 154 may communicate electronically with the steering sensor 158. Additionally, the DCU 156 may communicate electronically with the wheel speed sensors 160, 162, 164, 166.

[0043] Sensors that communicate electronically with the DCU 156 and / or VCU 154 include the steering sensor 158 for determining the vehicle steering angle, and the wheel speed sensors 160, 162, 164, 166 respectively connected to the wheel ends of the driveline 114, 118, 128, 130. A motor speed sensor may be connected to the motor or an inverter associated with the motor. The DCU 156 may communicate electronically with the motor control units 140, 142, 144, 146, 172. Additionally, the motor control unit 172 may communicate electronically with the motor 148 and the hydraulic pump 168. Thus, the motor control unit 172 can adjust the speeds of the electric motor 148 and the hydraulic pump 168.

[0044] The clutch actuation system 150 may include the motor 148, the hydraulic pump 168, and / or the hydraulic actuator 170. The hydraulic actuator 170 is connected to the clutch assemblies 120, 126 through hydraulic lines 171 and / or other suitable components. Figure 2 An example of a clutch drive system is shown and will be discussed in more detail herein.

[0045] Figure 1 Another motor control unit 172 is also shown, which is electrically coupled to the DCU 156 and the motor 148 and can adjust the speed of the motor 148. However, other motor control architectures can also be considered. The motor control unit 172 can be included in the control system 152.

[0046] The VCU 154 can be configured to manage traction drive operations, such as acceleration, braking, steering, etc. in forward and reverse drive modes. In addition, Figure 1 the control units shown in can be used to implement the methods and control techniques for adjusting the drive shaft configuration and the motors associated therewith described in more detail herein. The VCU 154 can receive various inputs from the input device 174 (e.g., accelerator pedal, brake pedal, drive mode selector (such as a gear selector), combinations thereof, etc.), with which the operator can interact to control the vehicle. In addition, the VCU 154 can send instructions to the DCU 156 based on the operator's interaction with the VCU. In addition, the DCU 156 can also control the power input to the motor control units 140, 142, 144, 146, 172. The motor control units 140, 142, 144, 146 can determine the rotational speed and direction of rotation of the motors corresponding to the control units based on the inputs from the DCU 156, thereby implementing the forward, reverse, stop, and steering functions of the electric vehicle. The electric motors 108, 110, 122, and 124 can convert electrical energy into mechanical energy and input it into the respective wheel end drive systems 114, 118, 128, and 130. The wheel end drive systems can transfer the mechanical energy to the drive wheels. In addition, speed sensors connected to the wheel end drive systems can be configured to provide speed signals (e.g., instantaneous speed signals) to the DCU 156 for verifying vehicle functions. The steering sensor 158 can be connected to the articulated frame and configured to generate a steering signal (e.g., instantaneous steering signal) for the DCU 156, which is used to verify the steering function.

[0047] Figure 1 and Figure 2-11 An axis system is included for reference. In one example, the Z-axis can be the vertical axis (e.g., parallel to the axis of gravity), the Y-axis can be the longitudinal axis (e.g., the horizontal axis), and / or the X-axis can be the transverse axis. However, in other examples, these axes may have other orientations.

[0048] Figure 2 An example of a clutch drive system 200 is shown. It can be understood that the clutch actuation system 200 is Figure 1 an example of the clutch actuation system 150 described in. However, in other examples, other clutch actuation techniques can also be used, such as pneumatic actuation systems, electromechanical actuation systems, combinations thereof, etc.

[0049] In the example, the clutch drive system 200 includes a motor control unit 202, which is electrically connected to a motor 204. The electric motor 204 is rotationally coupled to a pump 206, and the pump 206 includes an inlet 208 that is fluidly connected to an oil sump 210 for a working fluid (such as engine oil). Additionally, a filter 212 can be provided in the fluid line 214. The outlet 216 of the pump 206 is fluidly connected to a first flow control valve 218 and a second flow control valve 220. The first and second flow control valves 218, 220 can be electric valves that allow or inhibit fluid flow to the clutch actuators 222, 224. For example, the flow control valves can be electromagnetic flow control valves. Additionally, the hydraulic flow control valves 218, 220 can be designed to drain fluid into the oil sump when closed. The hydraulic flow control valves 218, 220 allow fluid to flow to the actuators 222, 224 when open and inhibit fluid flow to the actuators when closed.

[0050] Furthermore, a pressure sensor 226 can also be connected to fluid lines 228, 230, which are respectively connected to the flow control valves 218, 220 and the actuators 222, 224. Additionally, a relief valve 232 can be connected to fluid lines 234, 236 that connect the flow control valves 218, 220 and the pump 206. The function of the relief valve 232 is to allow fluid to flow into the chassis 210 when the pressure in the fluid line exceeds a threshold pressure.

[0051] The actuators 222, 224 can respectively include a piston 238 and a shaft 240, and the shaft 240 is connected to a clutch pack in a drive axle clutch (such as Figure 1 the clutch assemblies 120 and 126 shown). The actuators 222, 224 also include springs 242 connected to the pistons. When the pressure in the actuators increases above a threshold related to the spring constant, the clutch assemblies engage. Thus, the fluid pressure supplied to the actuators 222, 224 can be adjusted to cause clutch engagement and disengagement.

[0052] The arrows marked "ON" (open) and "OFF" (closed) in the hydraulic circuit generally indicate the direction of fluid flow in the circuit when the circuit is configured to respectively induce clutch engagement and clutch disengagement of each motor coupling clutch. It can be understood that the hydraulic circuit can adopt a variety of different configurations. For example, the hydraulic circuit can disengage or engage both clutches, or engage one clutch while disengaging the other. The clutch control strategy will be elaborated in Figure 12-15 detail.

[0053] Figure 3Shows an example of an electric drive axle 300 with a motor-coupled clutch assembly 302, the assembly having a motor-coupled clutch 303 configured to rotationally couple and decouple a first motor 304 and a second motor 306 (e.g., rotor shafts in the first and second motors).

[0054] The clutch assembly 302 may include a clutch housing 308, a clutch cover 310, a control valve body 312, a control valve cover 314, a hydraulic supply port 316, a pressure check port-regulator 318, a control valve pressure sensor 320, a flow control valve 322 (e.g., an electromagnetic flow control valve), a clutch pressure check port 324, a fluid inlet 326, a fluid outlet 328, fasteners 330 and 331, a housing-side sleeve 332, and / or a cover-side sleeve 334.

[0055] The control valve body 312 and the control valve cover 314 may be fixedly secured to the clutch housing 308 by means of fasteners 330. The housing and cover-side sleeves 332 and 334 may be connected to the motors 304 and 306 respectively by spline connections. The hydraulic supply port 316 may supply a fluid (e.g., oil) at a relatively high pressure to the clutch. The electromagnetic flow control valve 322 may receive instructions from the DCU to open or close the hydraulic supply to the clutch. The pressure check port-regulator 318, the control valve pressure sensor 320, and the clutch pressure check port 324 may use various sensors to assist in monitoring the fluid (such as oil) pressure at their respective locations. It can be understood that other electric drive axles in the electric vehicles described herein may have clutch assemblies with a similar layout. Figure 3 A cutting plane A-A' is provided, which plane corresponds to Figure 4 and Figure 5 the cross-sectional views described in

[0056] Figure 4 Shows a cross-sectional view of the electric drive axle 300 with the clutch assembly 302, particularly the motor-coupled clutch 303 in a disengaged state. Figure 4 An enlarged view 480 of the clutch assembly 302 is provided.

[0057] Figure 4The motor shafts 400 and 402 in motors 304 and 306 are described. The clutch housing 308 and the housing side sleeve 332 are again depicted in the figure. The clutch assembly 302 may further include ball bearings 404, rotary oil seals 406, snap rings 408, housing side clutch shaft 410, ball bearings 412 and 415, snap ring 414, cover side clutch shaft 416, clutch drum 418, clutch piston 421, piston seal 422, pressure plate 424, friction plates 426, clutch support plate 428, snap ring 430, clutch seal ring 432, spring retainers 420 and 434, piston return spring 436, snap ring 438, ball bearing 440, clutch cover 310, piston ring 444, O-ring seal 446, plug 448, cover side sleeve 450, rotary oil seal 452, ball bearing 454, snap ring 456, control valve body 312, control valve cover 314, control valve gasket 462, fasteners 464, control valve pressure sensor 466, electromagnetic flow control valve 322 and / or pressure relief valve 470.

[0058] The motor coupling clutch housing side sleeve 332 is connected to the motor shaft 400 on one side and to the housing side clutch shaft 410 by spline connection on the other side. The ball bearing 404 and the rotary oil seal 406 are mounted on the outer housing side sleeve 332. The snap ring 408 can be used to hold the ball bearing 404 and the rotary oil seal 406 in good condition with the clutch housing 308. The ball bearing 412 can be mounted on the outer housing side clutch shaft 410. The snap ring 414 (such as a spare snap ring) is used to hold the ball bearing 412 in good connection with the clutch housing 308. The ball bearing 415 is mounted between the outer housing side clutch shaft 410 and the cover side clutch shaft 416. The snap ring 414 can be used to hold the ball bearing 415 in good condition with the outer and cover side clutch shafts 410 and 416. The ball bearing 440 is mounted on the cover side clutch shaft 416 and is fixed within the clutch cover 310. The clutch drum 418 can be fixed to the cover side clutch shaft 416 by welding or other suitable connection techniques.

[0059] The clutch piston 421 is installed inside the cover-side clutch shaft 416 and can slide freely axially. The piston seal 422 can be installed on the clutch piston 421 to help reduce the leakage of the high-pressure oil for clutch actuation. The pressure plate 424 can be slidably interlocked with the outer diameter of the clutch drum 418 by means of a spline connection. The friction plate 426 can be slidably interlocked with the inner diameter of the housing-side clutch shaft 410 by means of a spline connection. The friction plate 426 can have friction linings installed on the opposite shaft sides. The friction plate 426 and the pressure plate 424 can be assembled alternately in sequence inside the clutch assembly. The clutch support plate 428 can be interlocked with the clutch drum 418 on the outer diameter by means of a spline connection. The snap ring 430 can be used to lock the sliding movement of the clutch support plate 428. The clutch seal ring 432 is installed between the housing-side clutch shaft 410 and the clutch support plate 428. The snap ring 420 can be fixed on the cover-side clutch shaft 416. The snap ring 438 can be used to keep one of the snap rings 434 intact with the cover-side clutch shaft 416. In addition, the snap ring 420 can be installed on the cover-side clutch shaft 416 and can slide freely axially together with the clutch piston 421. The piston return spring 436 can be installed between the spring holders 420 and 434. The piston ring 444 can be installed in the groove of the cover-side clutch shaft 416, and the groove is provided on both sides of the hydraulic supply port.

[0060] The piston ring 444 can reduce the leakage of the hydraulic oil pressure through the clearance of the cover-side clutch shaft assembly. The O-ring seal 446 can be installed in the groove of the cover-side clutch shaft to reduce the leakage of the high-pressure oil through the joint. The plug 448 can be used to close the ends of the oil holes in the clutch cover 310 and the cover-side clutch shaft 416. The ball bearing 454 and the rotary oil seal 452 can be installed on the cover-side sleeve 450. The snap ring 456 can be used to keep the ball bearing 454 and the rotary oil seal 452 intact with the clutch cover 310. One side of the motor-coupled clutch cover-side sleeve 450 can be connected to the cover-side clutch shaft 416, and the other side is connected to the motor shaft 402 by means of a spline connection. The control valve body 312 and the control valve cover 314 can be fixed to each other or fixed to the clutch housing 308 by means of the fasteners 464. The control valve gasket 462 can be used between the control valve body 312 and the clutch housing 308. The pressure relief valve 470 can be installed inside the control valve body 312. The pressure relief valve uses the mechanical force of the spring to keep the hydraulic oil pressure below the target value.

[0061] The rotating shaft 490 of the motor-coupled clutch 303 provides a reference together with the rotating shafts 492 of the motors 304, 306. In the illustration, these rotating shafts are coaxial. Additionally, the rotating shaft of the wheel-end drive system can also be arranged coaxially with the motors and the motor-coupled clutch. In this way, the compactness of the drive axle can be improved compared to the arrangement of non-coaxial drive axle components. However, in other examples, the rotating shafts of the motors and the clutch can be arranged non-coaxially. For example, in other examples, a gear reducer can be arranged between the clutch and the motor.

[0062] The motor shafts 400 and 402 are extensions of the motor rotor shafts and can be directly connected to the motor rotor shafts at the inner side 494 of the motors. The shafts 400 and 402 are rotationally coupled (e.g., splined, welded, crimped, combinations thereof, etc.) to the clutch shafts on opposite sides of the motor-coupled clutch 303.

[0063] Figure 5 An electric drive axle 300 is shown with the clutch assembly 302 in the engaged state, which enables torque to be transmitted between the rotor shafts of the motors 304 and 306. Figure 3-5 The component numbers in the electric drive axle 300 shown in are similar, and for the sake of brevity, the redundant descriptions of the components shown in are omitted. However, it can be understood that the clutch assembly 302 is in a disengaged configuration in, Figure 5 and in an engaged configuration in. Figure 4 Figure 5 Figure 5 An enlarged view 580 of the clutch assembly 302 is provided.

[0064] As Figure 5 shown, in the engaged configuration of the clutch assembly 302, the flow control valve 322 is in the open position. To place the flow control valve in the open position, the DCU or other suitable controller can issue an instruction to the flow control valve 322 to place the valve in the open position allowing fluid to be delivered to the clutch actuator. In this way, oil or other suitable fluid can flow from the oil sump to the pump, from the pump to the electromagnetic flow control valve 322, and then from the electromagnetic flow control valve to the clutch piston 421. The hydraulic fluid can flow through channels in the control valve body, the clutch housing, the clutch cover, and / or the cover-side clutch shaft. Specifically, the sequence of hydraulic fluid flow inside the clutch assembly 302 can be the control valve body 312, the clutch housing 308, the clutch cover 310, the cover-side clutch shaft 416, and the clutch piston 421.

[0065] The flow path of the hydraulic fluid is as Figure 5 ​​As shown by arrow 500. Pressurized hydraulic oil applies a force to the clutch piston 421, causing the clutch piston to move and apply a force to the separately rotating pressure plate 424 and friction plate 426. Then, the clutch piston 421 moves to axially press the alternately assembled pressure plate 424 and friction plate 426 against the stationary clutch support plate 428. The frictional resistance between the alternating pressure plates 424 and friction plates 426 binds the housing-side clutch shaft 410 and the cover-side clutch shaft 416 interlocked with these clutch plates together. Since the housing-side clutch shaft 410 and the cover-side clutch shaft 416 are connected to the two motor shafts 400 and 402, the driving forces of the two motor shafts are also combined. Thus, power can flow from either end motor to the other end motor. When the drive system control unit (DCU) issues a control command to adjust the flow control valve 322 to the release or "closed" position, the hydraulic oil can return from the motor coupling clutch assembly to the oil pan. In addition, the force acting on the clutch piston 421 is eliminated. The elastic force of the compression piston return spring 436 pushes the clutch piston 421 back to its initial position. The pressure plate 424 and the friction plate 426 start to rotate separately again. In this way, the motor coupling clutch disengages and separates the drives of the two end motors. However, in other examples, other clutch drive strategies can also be used for the clutch assembly. For example, the clutch assembly can be pneumatically driven, or the clutch assembly can be a synchronizer driven by a shift fork or other appropriate mechanism.

[0066] Figure 6 An example of an electric vehicle in the form of a mining truck 600 is shown. The mining truck 600 includes a front electric drive axle 602, a rear electric drive axle 604, and a dump box 606 or other suitable payload receiving assembly, the structure of which can receive a payload during operation. The electric drive axle can be referred to as an electric drive wheel system. The dump box 606 is specifically vertically disposed above the rear electric drive axle 604. However, in other examples, the dump box can also be disposed above the front drive axle or between the drive axles. The front electric drive axle and the rear electric drive axle can have a structure and / or function similar to any of the electric drive axles described herein.

[0067] Figure 7 Another example of an electric vehicle in the form of a load-haul-dump truck 700 is shown. The truck 700 also includes a front electric drive axle 702 and a rear electric drive axle 704. Similarly, the front electric drive axle and the rear electric drive axle can have a structure and / or function similar to any of the electric drive axles described herein. The truck 700 further includes a loader bucket 706 or other suitable payload receiving component located at the front of the vehicle.

[0068] Figure 6 and Figure 7The electric vehicle shown may have different payloads during use. Therefore, during operation, the configuration of the drive axle may vary. However, due to the different weight distributions of the vehicle, the drive axle control schemes may also be different. The method of changing the electric drive axle configuration will be described in detail in Figure 12-15 as follows.

[0069] Figure 8 Figure 6 shows an example of an electric vehicle 800 with a powertrain 801. The electric vehicle 800 also includes a first electric drive axle 802 (e.g., a front electric drive axle) and a second electric drive axle 804 (e.g., a rear electric drive axle). The electric vehicle 800 in the illustrated example includes an articulated frame 806 that can rotate about an axis 808. Figure 8 An enlarged view 850 of a portion of the first electric drive axle 802 and an enlarged cross-sectional view 852 of the steering sensor assembly at the steering pivot point between various parts of the chassis body of the electric vehicle 800 are provided in

[0070] The electric vehicle 800 may include different sub-assemblies and components, which may include a front chassis body 810, a rear chassis body 812, a steering sensor assembly 814, a high-voltage battery 816, a motor control unit (MCU) 818, a motor 820, a phase cable 822, a DC cable 824, a motor coupling clutch assembly 826, a wheel-end powertrain assembly 828, a rim 830, a wheel 832, fasteners 834, and bushings 836. Therefore, the electric vehicle 800 includes a powertrain 837 configured with an all-wheel drive function. In the illustrated example, the wheel-end powertrain assembly 828 and the motor control unit 818 are respectively fixed to the front and rear chassis bodies 810 and 812 of the vehicle.

[0071] The rear chassis body 812 may have a dump box pivotally connected thereto at portion 854. Therefore, the dump box may be disposed above or near the electric drive axle 804 (e.g., the rear electric drive axle). It can be understood that the motor coupling clutch can be adjusted according to the payload on the drive axle to improve the efficiency of the power transmission system. The motor coupling clutch control technology will be described in detail in Figure 12-15 as follows.

[0072] Each of the electric drive axles 802 and 804 includes two motors and a clutch assembly, similar to the electric drive axle described above in Figure 1-7 more generally, the electric drive axles 802 and 804 at least include some structural and / or functional features that overlap with the previously described electric drive axle. Therefore, for the sake of brevity, redundant descriptions are omitted.

[0073] The motor coupling clutch assembly 826 is mounted on the front and rear electric drive axles. Specifically, the motor coupling clutch assembly 826 is fixed to the front chassis main body 810 and the rear chassis main body 812 respectively. Both ends of the motor coupling clutch assembly 826 can be fixed to the chassis main bodies 810 and 812 by means of fasteners 834. The other end of the motor coupling clutch assembly can be supported on the chassis main bodies 810 and 812 by means of bushings 836. One end of each motor 820 can be connected to the corresponding wheel-end drive system assembly, and the other end can be connected to the corresponding motor coupling clutch assembly by splines and / or other suitable mechanical connection means. Each power input terminal of the electric motor 820 can be connected to the corresponding motor control unit through phase lines and / or other suitable electrical connections. The high-voltage battery 816 (such as a battery pack) can serve as the main power source for the motor and can be fixed to the rear chassis main body 812. The motor control unit 818 can be connected to the high-voltage battery 816 through a DC cable 824 and / or other suitable electrical connections. The steering arms are mounted on the rear chassis body 810 and the front chassis body 812. These arms are pivotally connected so that the rear chassis body 810 and the front chassis body 812 can pivot relative to each other about an axis 808, facilitating vehicle steering. The steering sensor assembly 814 can be firmly fixed within the pivot connection arms 840 and 842 provided separately. The rotation of the steering sensor assembly shaft 843 relative to the reference position will generate a signal indicating the magnitude of the vehicle steering angle. In a specific use case, an electric vehicle power system may use eight wheels (such as rims and tires). However, we have also envisioned electric vehicle power systems with other numbers of wheels. The electric vehicle can be steered by the coordinated operation of at least two motors on one of the drive shafts.

[0074] Figure 9 A top view of the electric vehicle 800 is shown. The high-voltage battery 816 (such as a battery pack) can provide DC power to the MCU 818 through a DC cable 824 and / or other suitable mechanical connections. The MCU 818 is configured to convert DC power to AC power and vice versa. The motor control unit 818 supplies AC power to the motor 820 through a phase line cable 822. In the illustrated example, the motor 820 converts AC power into mechanical power and transmits it to the wheel 832 through the wheel-end drive system assembly 828. Figure 9 The motor coupling clutch assembly 826 is further illustrated. As previously mentioned, each motor coupling clutch assembly 826 is configured to engage and disengage to rotationally couple and decouple the motors in the corresponding drive axles. Figure 9 The steering assembly 950 (such as a hydraulic cylinder) is further shown, which is coupled to the articulated frame to enable the electric vehicle to exhibit the desired steering characteristics.

[0075] Figure 10Shows an example of a wheel end assembly 1000, which may be included in any of the electric drive axles described herein. Specifically, the electric drive axle may include Figure 10 the two wheel end assemblies shown in and a motor coupling clutch. The wheel end assembly 1000 includes a motor 1002, which is rotationally coupled to a wheel end drive system 1004, and the wheel end drive system 1004 is rotationally coupled to a wheel hub 1006. The wheel end assembly 1000 may further include a motor control unit 1008, which is electrically coupled to the motor 1002. It can be understood that when the wheel end assembly is mounted on the drive shaft, the motor 1002 may include a shaft axially extending from the inner side 1010. Figure 10 Further shows a brake assembly 1011 (e.g., spring applied, hydraulically released brake assembly). The cutting plane B-B' defines Figure 11 the cross-sectional view described in.

[0076] Figure 11 Again shows the wheel end assembly 1000 with the motor 1002, the wheel end drive system 1004, the wheel hub 1006, and the brake assembly 1011. In the illustrated example, the wheel end drive system 1004 includes a planetary gear set 1100, which includes a sun gear 1102 that is rotationally coupled to the motor 1002 through a shaft 1104, and the shaft 1104 is coupled to the motor shaft 1106 (e.g., splined, crimped, welded, combinations thereof, etc.). The planetary gear set 1100 also includes a carrier 1108 rotationally coupled to a shaft 1110, and the shaft 1110 is connected to the wheel hub 1006. The planetary gear set 1100 also includes a ring gear 1112 and planetary gears 1114. Thus, the planetary gear set may be a simple planetary gear set. The brake assembly 1011 in the illustrated example includes a brake mechanism 1116 with friction plates 1118, an actuator 1120, etc. However, in other examples, the wheel end drive system may have various suitable structures. For example, the planetary gear set may take other forms or may include one or more pairs of gears to form a gear reduction stage. Additionally, in other examples, other suitable types of brakes may be used in the wheel end assembly.

[0077] Figure 12-13 Shows tables 1200 and 1300 corresponding to the control schemes of an electric vehicle power system 102, other electric vehicle power systems described herein, combinations of the power systems described herein, or other suitable electric vehicle power systems.

[0078] Table 1200 may correspond to an electric vehicle power system with a bed located above or near the rear electric drive axle, such as Figure 6 the EV 600 shown. Table 1300 may correspond to an electric vehicle power system with a loader bucket located near or above the front electric drive axle, such asFigure 7 The EV 700 shown. In addition, the columns in the table include the operating state of the electric vehicle, the configuration of the motors in the front and rear drive axles ("on" or "off"), and the configuration of the motor coupling clutches in the front and rear drive axles ("engaged" or "disengaged"). The "on" state of the motor indicates that the motor is generating torque, and the "off" state of the motor indicates that the motor is turned off and not generating torque. For details, Figure 1 The configurations of the motors 108, 110, 122, 124 and the motor coupling clutch assemblies 120, 126 shown in Figure 12-13 are as shown. However, it can be understood that the control schemes represented in Tables 1200 and 1300 can be used to control other suitable motors and / or clutches in other suitable electric drive axles. However, it can be understood that the motors 108, 110 and the motor coupling clutch assembly 120 are associated with the first electric drive axle (e.g., the front electric drive axle), and the motors 122, 124 and the motor coupling clutch assembly 126 are associated with the second electric drive axle (e.g., the rear electric drive axle). In addition, it can be understood that the control schemes represented in Tables 1200, 1300 can be executed by one or more controllers as instructions stored in a memory and executable by a processor. For example, the controller can determine the operating conditions and use the controller instructions to convert the motors and clutches to different configurations. The operating conditions include "low load / going straight", "high load / going straight", "turning", and "motor (122) and / or electronic hardware failure" related to the motor. The "low load / going straight" state corresponds to the state of the electric vehicle when the load on the drive axle is less than the threshold vehicle load and the steering angle is less than the threshold angle, indicating that the vehicle is going straight. On the other hand, the "higher load / going straight" operating condition corresponds to the operating condition of the electric vehicle when the load on the drive axle is greater than the threshold load and the steering angle is less than the threshold angle indicating that the vehicle is going straight. The "turning" state corresponds to the state of the electric vehicle when the steering angle is greater than the threshold angle, indicating that the vehicle is turning. The "motor (122) and / or electronic hardware failure" electric vehicle operating condition refers to the operating condition where the motor 122 cannot generate torque or the MCU electrically coupled to the motor cannot send power or otherwise operate the motor 122.

[0079] As Figure 12 shown in Table 1200 in, under the "low load / going straight" condition, the motors 108, 110 and 124 are in the "on" state, and the motor 122 is in the "off" state. In addition, the clutch assembly 120 is in the disengaged state, and the clutch assembly 126 is in the engaged state. In this way, compared with the situation where all motors are in the operating state and the clutch assemblies of each drive axle are in the disengaged state, the operating efficiency of the electric vehicle is higher. Therefore, the efficiency of the electric vehicle is improved.

[0080] In the "high load / going straight" state, motors 108, 110, 122, and 124 are in the "on" state, and clutch assemblies 120 and 126 are in the disengaged state. In this way, the electric vehicle can carry a higher payload. Similarly, in the "turning" state, motors 108, 110, 122, and 124 are in the "on" state, and clutch assemblies 120 and 126 are in the disengaged state.

[0081] In the "motor (122) and / or electronic hardware failure" state, motors 108, 110, and 124 are in the "on" state, and motor 122 is in the "off" state. In addition, clutch assembly 120 is in the disengaged state, and clutch assembly 126 is in the engaged state. In this way, the electric vehicle can operate normally when the motor fails.

[0082] As Figure 13 shown in Table 1300 in

[0083] In the "high load / going straight" state, motors 108, 110, and 124 are in the "on" state, motor 122 is in the "off" state, clutch assembly 120 is in the disengaged state, and clutch assembly 126 is in the engaged state. In this way, the electric vehicle can carry a larger payload more effectively.

[0084] In the "turning" state, motors 108, 110, 122, and 124 are in the "on" state, and clutch assemblies 120 and 126 are in the disengaged state.

[0085] In the "motor (122) and / or electronic hardware failure" state, motors 108, 110, and 124 are in the "on" state, motor 122 is in the "off" state. In addition, clutch assembly 120 is in the disengaged state, and clutch assembly 126 is in the engaged state. In this way, the electric vehicle can operate normally when the motor fails.

[0086] Figure 14 and Figure 15 show the operation methods 1400 and 1500 of the electric vehicle system. In one example, methods 1400 and 1500 can be passed as described above for Figure 1-11performed by any electric vehicle powertrain, system, etc. discussed, or a combination of powertrains, systems, etc. In particular, method 1400 can be implemented by an electric vehicle powertrain having a bed located above or adjacent to a rear electric drive axle, such as Figure 6 the electric vehicle 600 shown. Method 1500 can be implemented by an electric vehicle powertrain with a loader bucket located near or above a front electric drive axle, such as Figure 7 the EV 700 shown. However, in other examples, methods 1400 and 1500 can be implemented by other suitable powertrains, systems, etc. Instructions for performing methods 1400 and 1500 can be implemented by a controller or multiple controllers (such as VCU, DCU, MCU, etc.) by executing instructions stored in the controller memory and in combination with signals received from sensors on the controller. The controller can use actuators in different system components to perform the method steps described below.

[0087] Figure 14 The method 1400 shown can specifically correspond to a control strategy related to an electric drive axle (e.g., a rear electric drive axle). Method 1400 includes determining operating conditions at 1402. The operating conditions can be determined through sensor inputs and / or modeling.

[0088] Determining the operating conditions can include steps 1404 - 1410. At 1404, the method includes determining the wheel speeds of the drive wheels in the drive axles (e.g., front drive axle and rear drive axle). For example, the controller can receive inputs from wheel speed sensors coupled to the wheel end components in each drive axle.

[0089] At 1406, the method includes determining the steering angle. For example, the controller can receive inputs from a steering angle sensor, which can be included in an articulated frame. For example, the wheel steering angle and the steering sensor output can be calibrated in step 1406.

[0090] At 1408, the method includes determining the electrical energy delivered to the motor. For example, the electrical energy allocated to the motor can be determined by sensors in the MCU (such as an inverter).

[0091] At 1410, the method includes determining the total drive axle load. For example, the power delivered to the motor can be used to determine the vehicle load, particularly the load on the drive axle. For example, the vehicle load and the relative power consumption of the motor need to be calibrated or tested. During the calibration process, various loads on the vehicle and / or drive axle can be tested. Additionally, the motor power consumption at different drive axle load values can be recorded. This will provide a correlation between power consumption and drive axle load. Based on the motor power consumption read by the controller under actual operating conditions, the same correlation can be used to determine the drive axle load.

[0092] At 1412, the method includes determining whether the vehicle load (e.g., drive axle load) is less than a threshold vehicle load (e.g., a non - zero value). The vehicle threshold vehicle load value can be determined by calibrating or testing the vehicle. The motor power consumption for various drive axle load values can be recorded. This will provide a correlation between power consumption and drive axle load. Under actual operating conditions, based on the motor power consumption read by the controller, the same correlation can be used to determine the axle load. The threshold vehicle load value may be a relatively low axle load value during unloaded driving, in which case only one motor can carry the load. Thus, the vehicle threshold vehicle load value can be determined by testing at which a single motor can push the two wheels of the drive axle at the required speed and the motor efficiency is also improved. Then, the vehicle DCU can be programmed based on a threshold set for the equivalent motor power consumption parameter to control the operation of the motor coupling clutch. If it is determined that the vehicle load is not less than the threshold (NO at 1412), the method proceeds to 1414, where the method includes keeping the motor coupling clutch disengaged. Next, at 1416, the method includes maintaining the operation of the two motors in the electric drive axle.

[0093] If it is determined that the vehicle load is less than the threshold ("Yes" at 1412), the method proceeds to 1418. At 1418, the method includes determining whether the steering angle is greater than a threshold angle. The threshold angle can be determined by testing at which the vehicle can turn slightly without tire resistance. Then, the vehicle DCU can be programmed to control the operation of the motor coupling clutch based on constraints set for the equivalent steering sensor output parameter. If it is determined that the steering angle is greater than the threshold angle ("Yes" at 1418), the method proceeds to 1414. Conversely, if it is determined that the steering angle is not greater than the threshold angle (NO at 1418), the method proceeds to 1420. At 1420, the method includes suppressing the operation of one motor in the drive axle. In this way, the power of the drive axle is protected. More specifically, the efficiency loss of the motor is reduced, so that the operating resources can be reduced and a smooth speed and operation can be achieved within the required range, while reducing noise, vibration, and harshness (NVH). In addition, since the power consumption of the relevant electronic circuits during vehicle operation is reduced, turning off the operation of one of the motors can extend the service life of the motor and the relevant electronic hardware components.

[0094] Next, at 1422, the method includes engaging the motor coupling clutch to the electric drive axle. In this way, when one of the motors is turned off to improve the efficiency of the drive axle, the drive axle can push the vehicle in the required direction.

[0095] At 14:24, the method includes maintaining vehicle movement. For example, a running electric motor can continue to operate to propel the vehicle in a desired direction. Method 1400 can be applied to any electric drive axle in an electric vehicle. More specifically, method 1400 can be applied to an electric drive axle that receives a vehicle payload.

[0096] Figure 15 The illustrated method 1500 includes determining operating conditions at 1502. The operating conditions can likewise be determined through sensor inputs and / or modeling.

[0097] Determining the operating conditions can include steps 1504 - 1510. Steps 1504 and 1506 are similar (e.g., identical) to steps 1406 and 1408. Thus, for the sake of brevity, redundant descriptions are omitted.

[0098] At 1508, the method includes determining the electrical energy delivered to the motors in each drive axle. For example, the electrical energy allocated to the motors can be determined by sensors in an MCU (such as an inverter).

[0099] At 1510, the method includes determining the total load at the front and rear of the vehicle. For example, the power delivered to the motors can be used to determine the vehicle load, particularly the load on each drive axle. For example, the vehicle load and the relative power consumption of the motors can be calibrated or tested. During calibration, various loads on the vehicle, front drive axle, and rear drive axle can be tested. The motor power consumption will be recorded for various front and rear axle load values. This will provide a correlation between power consumption and front / rear axle load. Based on the motor power consumption read by the controller in the actual operating state, the same correlation can be used to determine the front axle or rear axle load.

[0100] Next, at 1512, the method includes determining whether the load on the front drive axle is less than a threshold value (e.g., a non-zero value). The vehicle threshold vehicle load value can be determined by calibrating or testing the vehicle. The motor power consumption for various front and rear axle load values can be recorded. This can provide a correlation between power consumption and front / rear axle load. Based on the motor power consumption read by the controller under actual operating conditions, the same correlation can be used to determine the front and rear axle loads. The threshold vehicle load value may be a low value of the front or rear axle load, in which case only one motor can carry the load. Therefore, the vehicle threshold vehicle load can be determined through testing, at which value a single motor can drive the two wheels of the front / rear drive axle at the required speed and the motor efficiency is also improved. Then, the vehicle DCU can be programmed to control the operation of the motor coupling clutch based on the threshold set for the equivalent motor power consumption parameter. If it is determined that the front axle load is not less than the threshold (NO at 1512), the method proceeds to 1514, where the method includes disengaging or continuously disengaging the motor coupling clutch. Next, at 1516, the method includes maintaining the operation of the two motors in the front electric drive axle.

[0101] If it is determined that the front axle load is less than the threshold ("Yes" at 1512), the method proceeds to 1518. At 1518, the method includes determining whether the steering angle is greater than a threshold angle. The threshold angle can be determined by testing the vehicle while steering slightly without tire resistance. Then, the vehicle DCU can be programmed to control the operation of the motor coupling clutch based on the constraints set for the equivalent steering sensor output parameter. If it is determined that the steering angle is greater than the threshold angle ("Yes" at 1518), the method proceeds to 1514. Conversely, if it is determined that the steering angle is not greater than the threshold angle (NO at 1518), the method proceeds to 1520. At 1520, the method includes suppressing the operation of one electric motor in the front electric drive axle. In this way, power is saved on the front drive axle. Next, at 1522, the method includes engaging the motor coupling clutch in the front electric drive axle. In this way, the front drive axle can push the vehicle in the required direction while one of the electric motors is turned off to improve the drive axle efficiency.

[0102] Steps 1524 - 1534 are similar to steps 1512 - 1522, and for the sake of brevity, the redundant description is omitted. However, it can be understood that steps 1512 - 1522 apply to the front electric drive axle, while steps 1524 - 1534 apply to the rear electric drive axle. Additionally, in one example, the threshold vehicle loads for steps 1512 and 1524 may be similar. However, in other examples, the threshold loads for different drive axles may be different. In some examples, this threshold load difference may be due to the use of different sized motors for the front and rear drive axles. However, as described above, in other examples, the motors for each drive axle may be similar in size, but the loads on the axles may be different.

[0103] At 1536, the method includes maintaining vehicle motion. For example, the motor may be continuously operated to propel the vehicle in a desired direction. Methods 1400 and 1500 allow adjustment of the motor coupling clutches in one or more drive axles based on the drive axle load to improve the efficiency of the powertrain. Thus, the driving range of the electric vehicle can be increased, thereby enhancing the attractiveness to customers.

[0104] The technical effect of the electric vehicle operation method described herein is to improve the efficiency of the powertrain under a wider range of operating conditions that the vehicle may experience, such as different degrees of load that may occur during vehicle operation. The electric vehicle operation method described herein can further improve the reliability of the electric vehicle, even if one of the traction motors fails to operate.

[0105] Figure 3-5 and Figure 8-11 Except for the components schematically depicted, they are drawn approximately to scale. However, in other embodiments, these components may have other relative dimensions.

[0106] Figure 1-11 Configuration examples showing the relative positioning of various components are presented. If the elements shown in the figure are in direct contact or directly coupled to each other, then in at least one example, these elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements shown as being contiguous or adjacent to each other may be contiguous or adjacent to each other, respectively. For example, elements in face-to-face contact with each other may be referred to as face-to-face contact elements. Another example is that in at least one example, elements that are placed separately from each other with only space in between and no other elements may be referred to as being placed separately from each other. Also, for example, elements shown above / below each other, on opposite sides of each other, or on the left / right side of each other relative to each other may be referred to as such elements. Additionally, as shown in the figure, in at least one example, the topmost element or element point may be referred to as the "top" of the element, and the bottommost element or element point may be referred to as the "bottom" of the element. The top / bottom, upper / lower, above / below used herein may be relative to the vertical axis in the figure and are used to describe the positioning of the various elements in the figure relative to each other. Thus, in one example, an element shown above other elements is vertically positioned above the other elements. Again, for example, the shapes of the elements depicted in the figure may be referred to as having these shapes (such as circular, straight, planar, curved, rounded, chamfered, beveled, or similar shapes). Additionally, in one example, elements that are coaxial with each other may be referred to as coaxial elements. Furthermore, in at least one example, elements shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Additionally, in one example, an element shown inside another element or shown outside another element may be referred to as an intersecting element. In other examples, elements that are offset from each other may also be referred to as "elements". Elements arranged parallel or perpendicular to other elements may also be referred to as "elements".

[0107] The present disclosure will be further described below. In one aspect, there is provided an electric vehicle (EV) system including an electric drive axle including a first electric motor configured to transfer mechanical power to a first drive wheel; a second electric motor configured to transfer mechanical power to a second drive wheel; an electric motor coupling clutch configured to selectively rotationally couple the first electric motor to the second electric motor; and a controller including instructions that, when executed, cause the controller to selectively rotationally couple the first electric motor to the second electric motor according to a vehicle load by operating the electric motor coupling clutch.

[0108] In another aspect, there is provided a method of operating an electric vehicle (EV) system, the method including decoupling a motor coupling clutch to rotationally decouple a first motor and a second motor included in an electric drive axle according to a vehicle load and a steering angle of the electric vehicle system, wherein the electric drive axle includes a first motor configured to transfer mechanical power to a first drive wheel and a second motor configured to transfer mechanical power to a second drive wheel.

[0109] In yet another aspect, there is provided an electric vehicle (EV) system including a first motor configured to transfer mechanical power to a first drive wheel, a second motor configured to transfer mechanical power to a second drive wheel, an electric motor coupling clutch configured to selectively rotationally couple the first motor to the second motor, and a controller including instructions that, when executed, cause the controller to rotationally couple the first motor to the second motor by operating the electric motor coupling clutch, cause the controller to rotationally couple the first motor to the second motor by operating the electric motor coupling clutch when the steering angle is less than a threshold angle and the vehicle load is greater than a threshold vehicle load, and operate the first motor to provide mechanical power to the first and second drive wheels when the second motor is turned off.

[0110] In any of the above aspects or combinations of aspects, selectively rotationally coupling the first motor to the second motor may include rotationally coupling the first motor to the second motor in response to the vehicle load dropping below a threshold.

[0111] In any of the above aspects or combinations of aspects, the controller may further include instructions that, when executed, cause the controller to maintain rotational decoupling between the first motor and the second motor when the vehicle steering angle exceeds a threshold angle and the vehicle load is below a threshold vehicle load.

[0112] In any of the above aspects or combinations of aspects, selectively rotationally coupling the first motor to the second motor may include rotationally coupling the first motor to the second motor when the steering angle is less than a threshold angle.

[0113] In any of the above aspects or combinations of aspects, the controller may further include instructions that, when executed, in response to the vehicle load decreasing below a threshold and when the steering angle is less than a threshold angle, cause the controller to operate the first motor to provide mechanical power to the first and second drive wheels while the second motor is shut off.

[0114] In any of the above aspects or combinations of aspects, the electric drive axle may be a rear electric drive axle, and the electric vehicle system may be included in an electric vehicle with the payload receiving assembly positioned adjacent to and / or above the rear electric drive axle.

[0115] In any of the above aspects or combinations of aspects, the motor coupling clutch may be a friction clutch.

[0116] In any of the above aspects or combinations of aspects, the friction clutch may be hydraulically actuated by a hydraulic drive system.

[0117] In any of the above aspects or combinations of aspects, the controller may be a motor control unit that communicates electronically with a drive motor in the hydraulic drive system.

[0118] In any of the above aspects or combinations of aspects, the first motor, the second motor, the first drive wheel, and the second drive wheel may be coaxially arranged.

[0119] In any of the above aspects or combinations of aspects, the vehicle load may be determined based on the torque demands of the first and second motors.

[0120] In any of the above aspects or combinations of aspects, the motor coupling clutch may be engaged when the vehicle load drops below a threshold.

[0121] In any of the above aspects or combinations of aspects, the method may further include disengaging the motor coupling clutch when the steering angle exceeds a threshold and / or the vehicle load exceeds a threshold.

[0122] In any of the above aspects or combinations of aspects, the controller may further include instructions that, when the steering angle is greater than a threshold angle, execution of which causes the controller to rotate the first motor out of phase with the second motor by operating the motor coupling clutch; operate the first motor to provide mechanical power to the first drive wheel; and operate the second motor to provide mechanical power to the second drive wheel.

[0123] In any of the above aspects or combinations of aspects, the motor coupling clutch may be a hydraulically operated friction clutch.

[0124] In any of the above aspects or combinations of aspects, the electric vehicle system may be included in an off - highway vehicle.

[0125] In the above aspects or combinations of aspects, the vehicle load may be determined based on the power consumption of the first motor and the second motor.

[0126] In one aspect, an electric vehicle (EV) system is provided that includes a first electric drive axle including a first pair of electric motors configured to respectively transfer mechanical power to a first drive wheel and a second drive wheel; and a first motor coupling clutch configured to selectively rotationally couple the first pair of electric motors to each other; and a second electric drive axle including a second pair of electric motors configured to respectively transfer mechanical power to a third drive wheel and a fourth drive wheel; and a second motor coupling clutch configured to selectively rotationally couple the second pair of electric motors to each other; and a controller configured to selectively engage the first and / or second motor coupling clutches based on the vehicle load.

[0127] In another aspect, a method of operating an electric vehicle system is provided that includes selectively engaging a first motor coupling clutch and a second motor coupling clutch on a first electric drive axle and a second electric drive axle based on the vehicle load and the steering angle; wherein the first electric drive axle includes electric motors located on opposite sides of the drive axle that are rotationally coupled to the first motor coupling clutch; and the second electric drive axle includes electric motors located on opposite sides of the drive axle that are rotationally coupled to the second motor coupling clutch.

[0128] In another aspect, an electric vehicle (EV) system is provided that includes a first electric drive axle including a first pair of electric motors configured to respectively transfer mechanical power to a first drive wheel and a second drive wheel; a first motor coupling clutch configured to selectively rotationally couple the first pair of electric motors to each other; and a second electric drive axle including a second pair of electric motors configured to respectively transfer mechanical power to a third drive wheel and a fourth drive wheel; a second motor coupling clutch configured to selectively rotationally couple the second pair of electric motors to each other; and a controller including instructions stored in a memory that, when executed when the steering angle is below a threshold, cause the controller to engage the first motor coupling clutch when the load on the first electric drive axle is below a threshold.

[0129] In any of the above aspects or combinations of aspects, selectively engaging the first and / or second motor coupling clutches may include engaging one of the motor coupling clutches while disengaging the other motor coupling clutch.

[0130] In any of the above aspects or combinations of aspects, selectively engaging the first and / or second motor coupling clutches may include engaging the first motor coupling clutch when the load on the first electric drive axle decreases below a threshold and the steering angle is below a threshold.

[0131] In any of the above aspects or combinations of aspects, selectively engaging the first and / or second motor coupling clutches may include disengaging the first motor coupling clutch when the load on the first electric drive axle increases above a threshold and / or the steering angle exceeds a threshold.

[0132] In any of the above aspects or combinations of aspects, the controller may further be configured to turn off one of the motors in the first pair of electric motors when the other motor is operating.

[0133] In any of the above aspects or combinations of aspects, selectively engaging the first and / or second motor coupling clutches may include engaging the second motor coupling clutch when the load on the second electric drive axle decreases below a threshold and the steering angle is below a threshold.

[0134] In any of the above aspects or combinations of aspects, selectively engaging the first and / or second motor coupling clutches may include disengaging the second motor coupling clutch when the load on the second electric drive axle increases above a threshold and / or the steering angle exceeds a threshold.

[0135] In any of the above aspects or combinations of aspects, the controller may further be configured to turn off one of the motors in the second pair of electric motors when the other motor is operating.

[0136] In any of the above aspects or combinations of aspects, the electric vehicle system may further include axle end assemblies located between each electric motor and the drive wheels in the first and second electric drive axles.

[0137] In any of the above aspects or combinations of aspects, the first and second motor coupling clutches may be friction clutches.

[0138] In any of the above aspects or combinations of aspects, the electric vehicle system may further include an articulated frame.

[0139] In any of the above aspects or combinations of aspects, the electric vehicle system may be included in a heavy-duty off-highway vehicle.

[0140] In any of the above aspects or combinations of aspects, the first pair of electric motors may be coaxially positioned with the first motor coupling clutch; the second pair of electric motors may be coaxially positioned with the second motor coupling clutch.

[0141] In any of the above aspects or combinations of aspects, selectively engaging the first motor coupling clutch and the second motor coupling clutch may include engaging the first motor coupling clutch in response to the load on the first electric drive axle decreasing below a threshold, and disengaging the second motor coupling clutch in response to the load on the second electric drive axle increasing above a threshold; and the method may further include turning off one of the motors in the first electric drive axle while maintaining the operation of the other motor in the first electric drive axle.

[0142] In any of the above aspects or combinations of aspects, the controller may further include instructions stored in a memory that, when executed when the steering angle is below a threshold, cause the controller to engage a second motor coupling clutch when the load on the second electric drive axle is below a threshold.

[0143] In any of the above aspects or combinations of aspects, the controller may further include instructions stored in a memory that, when executed when the steering angle is below a threshold, cause the controller to turn off one motor of a second pair of motors while the other motor of the second pair of motors is powered on when the load on the second electric drive axle is below a threshold.

[0144] In any of the above aspects or combinations of aspects, the controller may further include instructions stored in a memory that, when executed when the steering angle is below a threshold, cause the controller to turn off one motor of a first pair of motors while the other motor of the first pair of motors is operating when the load on the first electric drive axle is below a threshold.

[0145] In any of the above aspects or combinations of aspects, the electric vehicle system may further include an articulated frame, and the steering angle may be measured by a sensor coupled to a pivot of the articulated frame.

[0146] In any of the above aspects or combinations of aspects, the motor coupling clutch may be a dog clutch.

[0147] In another representation, an electric vehicle system is provided that includes a plurality of drive axles, each drive axle including a traction motor that is rotationally coupled to wheels on opposite sides of the drive axle and coupled to an articulated frame, wherein each drive axle includes a clutch configured to temporarily rotationally connect the traction motor in accordance with a vehicle load.

[0148] Note that the control and estimation routine examples included herein may be used with a variety of powertrains, electric drive units, and / or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in a non-transitory memory and may be executed by a control system that includes a variety of sensors, actuators, and other driveline and / or vehicle hardware in combination with an electronic controller. Accordingly, the actions, operations, and / or functions described may be graphically represented as code programmed into the non-transitory memory of a computer-readable storage medium of a vehicle and / or driveline control system. The various operations, runs, and / or functions illustrated may be executed in the order illustrated, may be executed in parallel, or in some cases may be omitted. Similarly, the order of processing is not necessarily required to implement the features and advantages of the examples described herein, but is provided for ease of illustration and description. One or more of the actions, operations, and / or functions illustrated may be repeated in accordance with a particular strategy employed. One or more method steps described herein may be omitted if desired.

[0149] Although the various embodiments have been described above, it should be understood that these embodiments are merely examples and not limitations. It will be apparent to those skilled in the relevant art that the disclosed subject matter can be embodied in other specific forms without departing from the spirit of the subject matter. Accordingly, the embodiments described above should be considered illustrative in all respects and not restrictive. Thus, the configurations and routines disclosed herein are exemplary in nature, and these specific examples should not be considered restrictive as there can be many variations. For example, the above techniques can be applied to power systems incorporating different types of propulsion sources, including different types of electric motors, internal combustion engines, and / or drive units. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions, and / or characteristics disclosed herein.

[0150] The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. These claims are to be understood as including one or more such elements, neither requiring nor precluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or characteristics may be claimed by modifying this claim or presenting new claims in this application or a related application. These claims, whether broader, narrower, the same, or different in scope from the original claims, are also regarded as included in the subject matter of the present disclosure.

Claims

1. An electric vehicle (EV) system, characterized in that: The electric vehicle (EV) system comprises: Electric drive axle, including: a first motor for transmitting mechanical power to a first drive wheel; a second motor for transmitting mechanical power to a second drive wheel; a motor coupling clutch that selectively rotationally couples the first motor and the second motor; and A controller, which contains instructions that, when executed, cause the controller to: The first electric machine is selectively rotationally coupled to the second electric machine by operation of the electric machine coupling clutch according to a vehicle load. 2 . The electric vehicle system of claim 1 , wherein selectively rotationally coupling the first electric machine to the second electric machine comprises rotationally coupling the first electric machine to the second electric machine in response to the vehicle load decreasing below a threshold vehicle load.

3. The electric vehicle system of claim 2, wherein the controller further includes instructions that, when the vehicle steering angle exceeds a threshold angle and the vehicle load is below a threshold vehicle load, cause the controller to: Rotational decoupling between the first electric machine and the second electric machine is maintained. 4 . The electric vehicle system of claim 2 , wherein selectively rotationally coupling the first motor to the second motor comprises rotationally coupling the first motor to the second motor when a steering angle is less than a threshold angle.

5. The electric vehicle system of claim 2, wherein the controller further includes instructions that, in response to the vehicle load dropping below a threshold vehicle load and when the steering angle is less than a threshold angle, cause the controller to: The first motor is operated to provide mechanical power to the first and second drive wheels when the second motor is turned off.

6. The electric vehicle system of claim 1, wherein the electric drive axle is a rear electric drive axle, and the electric vehicle system is included in an electric vehicle with a payload receiving assembly positioned adjacent to and / or above the rear electric drive axle.

7. The electric vehicle system of claim 1, wherein the motor coupling clutch is a friction clutch.

8. The electric vehicle system according to claim 7, wherein the friction clutch is hydraulically driven by a hydraulic drive system.

9. The electric vehicle system of claim 8, wherein the controller is a motor control unit in electronic communication with a drive motor in the hydraulic drive system. 10 . The electric vehicle system according to claim 1 , wherein the first motor, the second motor, the first drive wheel, and the second drive wheel are coaxially arranged.

11. The electric vehicle system of claim 1, wherein the motor coupling clutch is a dog clutch, and wherein determining the vehicle load based on torque and speed requirements of the first motor and the second motor; or The vehicle load is determined according to power consumption of the first motor and the second motor.

12. The electric vehicle system of claim 1, wherein the controller further comprises instructions that, when the steering angle is greater than a threshold angle, cause the controller to: Decoupling the rotation of the first motor and the second motor by operating the motor coupling clutch; as well as operating the first motor to provide mechanical power to the first driving wheel; as well as The second motor is operated to provide mechanical power to the second drive wheel.

13. The electric vehicle system of claim 1, wherein the motor coupling clutch is a hydraulically operated friction clutch.

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