Work vehicle and control system for providing multi-stage braking and deceleration

Abstract

The present disclosure relates to a work vehicle and a control system for providing multi-stage braking and deceleration. A control system for implementing multi-stage braking and deceleration in a work vehicle is provided, the work vehicle including a hybrid electric drive system having an engine and one or more electric machines. The control system includes a braking and deceleration system that dissipates energy generated by motion of the work vehicle, wherein the braking and deceleration system includes a braking resistor, an engine brake, and a transmission operable to provide transmission braking. A controller receives inputs regarding a braking torque demand and operating parameters of the hybrid electric drive system and the braking and deceleration system, determines an amount of energy absorption necessary to satisfy the braking torque demand, and allocates the energy to be absorbed within the braking and deceleration system according to a tiered energy allocation scheme based on the energy to be absorbed and the operating parameters of the hybrid electric drive system and the braking and deceleration system.

Description

Technical Field

[0001] This disclosure generally relates to braking systems for work vehicles, and more specifically, to multi-stage braking and deceleration systems for work vehicles. Background Technology

[0002] Large work vehicles such as articulated dump trucks and semi-trailers often require significant braking power to control their speed, especially when descending steep slopes or carrying heavy loads. Therefore, these vehicles are typically equipped with at least two types of braking systems, employing both friction braking and deceleration systems. Friction braking effectively slows the vehicle, but it wears down easily and requires maintenance or replacement if used too frequently. Deceleration systems can include devices such as engine brakes and fluid decelerators, which, for example, reduce vehicle speed by controlling the engine or transmission. Engine brakes utilize pressure generated within the engine (including by selectively operating exhaust valves to control or alter the compression stroke) to slow the vehicle. Fluid decelerators can be incorporated into the transmission to absorb some of the momentum associated with the vehicle, where viscous resistance is induced in the fluid drawn through the decelerator, thereby absorbing energy through the drive shaft and slowing the vehicle. Summary of the Invention

[0003] A control system is provided for providing multi-stage braking and deceleration in a work vehicle, the work vehicle including a hybrid electric drive system having an engine and one or more electric motors. The control system includes a braking and deceleration system configured to dissipate energy generated by the motion of the work vehicle, wherein the braking and deceleration system further includes a braking resistor, an engine brake, and a transmission operable to provide transmission braking. The control system also includes a controller including a processor and memory architecture, the controller being operatively connected to the hybrid electric drive system and the braking and deceleration system. The controller is configured to: receive multiple inputs, including braking torque requirements from an operator and operating parameters of the hybrid electric drive system and the braking and deceleration system; determine the amount of energy absorbed in the work vehicle necessary to meet the braking torque requirements; and distribute the energy to be absorbed within the braking and deceleration system according to a tiered energy distribution scheme, wherein the energy is distributed based on the determined energy absorption amount and the operating parameters of the hybrid electric drive system and the braking and deceleration system.

[0004] In another implementation, a work vehicle includes a drivetrain comprising an engine, one or more electric motors, and a transmission for selectively transmitting power from at least one of the engine and the one or more electric motors to an output shaft. The work vehicle also includes a braking and deceleration system configured to dissipate energy generated by the movement of the work vehicle, wherein the braking and deceleration system has a braking resistor, an engine brake, and transmission braking provided by the transmission. The work vehicle also includes a controller comprising a processor and memory architecture, the controller communicating with the drivetrain and the braking and deceleration system. The controller is configured to: receive multiple inputs, including braking torque requirements from an operator and operating parameters of the drivetrain and the braking and deceleration system; determine the amount of energy absorbed in the work vehicle necessary to meet the braking torque requirements; and distribute the energy to be absorbed within the braking and deceleration system according to a tiered energy distribution scheme, wherein the energy is distributed based on the determined energy absorption amount and the operating parameters of the hybrid electric drive system and the braking and deceleration system.

[0005] Details of one or more embodiments are set forth in the accompanying drawings and the following description. Other features and advantages will become apparent from the specification, drawings, and claims. Attached Figure Description

[0006] At least one example of this disclosure will be described below with reference to the following figures:

[0007] Figure 1 An example work vehicle comprising a control system providing multi-stage braking and deceleration, according to an embodiment, is illustrated;

[0008] Figure 2 yes Figure 1 A schematic diagram of a hybrid electric drive system for a work vehicle, including an example continuously variable transmission (CVT).

[0009] Figure 3 It provides targeted Figure 1 A block diagram of the inputs and components of a multi-stage braking and deceleration control system for work vehicles; and

[0010] Figure 4 It is a flowchart used to provide a multi-stage braking and deceleration control scheme for work vehicles.

[0011] In the various figures, similar reference numerals indicate similar elements. For the sake of simplicity and clarity, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the following detailed description. It should be further understood that, unless otherwise stated, features or elements appearing in the figures are not necessarily drawn to scale. Detailed Implementation

[0012] Embodiments of the present disclosure are illustrated in the accompanying drawings, which are briefly described above. Those skilled in the art will anticipate various modifications to the exemplary embodiments without departing from the scope of the invention as set forth in the appended claims.

[0013] Overview

[0014] As previously mentioned, operational vehicles such as dump trucks and semi-trailers often utilize reduction gear systems to provide braking power when descending steep slopes or carrying heavy payloads. In operational vehicles with conventional transmissions, the reduction gear system can utilize a dedicated fluid reducer or an existing torque converter operating as a fluid reducer to provide deceleration by absorbing a portion of the momentum associated with the vehicle. The fluid reducer can be directly mounted to the transmission, with its blades attached to the transmission driveshaft between the clutch and the drive wheels. The blades are enclosed in a static chamber with minimal clearance to the chamber walls, which are also bladed. When the fluid reducer is actuated, compressed air draws fluid (e.g., standard transmission fluid (gear oil), a separate oil supply, or water) into the chamber, which has a stator on one side and a rotor on the other. The rotational motion of the rotor accelerates the fluid and generates a torque that pulls the rotor via helical gears. The stator returns the fluid to the rotor, an action that generates a braking torque or viscous resistance that decelerates the rotor, thereby transmitting braking power to the vehicle's drive wheels. During operation, the fluid reducer can dissipate a large amount of energy generated by the vehicle, making it an effective mechanism for providing braking power.

[0015] While fluid reducers effectively provide braking power in work vehicles, it should be recognized that including a fluid reducer in some work vehicles and their transmission systems may be impractical. For example, in work vehicles with hybrid electric transmissions (or electric continuously variable transmissions (eIVTs)), torque converters or dedicated fluid reducers are typically not included, and the addition of such a fluid reducer can be costly and cumbersome to mount on the vehicle. However, excluding fluid reducers from work vehicles can result in a significant amount of residual vehicle energy that must be dissipated through other braking and deceleration mechanisms.

[0016] To provide energy dissipation in work vehicles without using a fluid reducer, a control system is provided for work vehicles with a hybrid electric drivetrain, which implements multi-stage braking and deceleration schemes within the vehicle. This control system utilizes various energy storage and dissipation devices to absorb energy from the vehicle, including battery storage devices, braking resistors, engine brakes, axle brakes, engine friction, cooling fans, and other engine accessories. The control system can be implemented in conjunction with an eIVT system, where the control system operates the eIVT as an additional means of providing transmission braking for energy absorption.

[0017] In this implementation, the control system employs a closed-loop control scheme to apply multi-stage braking and deceleration control to the work vehicle. When implementing the control scheme, the controller in the control system receives operator commands related to the braking torque requested for the work vehicle. The controller calculates the kinetic force that will need to be absorbed in the vehicle to accommodate the braking torque and compares the calculated kinetic force with multiple vehicle operating parameters monitored in the work vehicle to determine an appropriate scheme for distributing power among energy storage and dissipation devices in the work vehicle. The controller then distributes the power among the energy storage and dissipation devices in the vehicle using a multi-stage hierarchical method to optimally distribute the power. According to an example, the controller provides an ordered deceleration power distribution that optimizes the use and dissipation of the power. First, power can be directed to one or more energy storage devices (e.g., battery packs) in the work vehicle to store as much power as possible. Then, the remaining power is distributed among other accessories on the work vehicle that may consume power and to non-wearing components of the work vehicle that can dissipate significant amounts of power. As another means of dissipating power, wearing components on the vehicle can be engaged to further dissipate power in the work vehicle.

[0018] In one implementation, if the required power absorbed in connection with the operator's command is too high to be suitable for use in the vehicle, the controller can also modify the braking torque requested in the operator's command. The controller can issue a reverse command to reduce the braking torque requested for the work vehicle, thereby reducing the amount of power that must be absorbed in the vehicle. By using the reverse command, combined with the power distribution among the vehicle's energy storage and dissipation devices as described above, the control system provides protection for various components of the work vehicle, including, for example, the engine, brakes, and transmission clutch.

[0019] According to this disclosure, Figures 1 to 4The present invention provides an example implementation of a work vehicle having a hybrid electric transmission and a control system that implements a multi-stage braking and deceleration scheme within the vehicle. While the following example is provided, other types of work vehicles and other configurations of hybrid electric transmission systems will also benefit from the multi-stage braking and deceleration schemes of the invention incorporated herein. Therefore, it should be understood that aspects of the invention are not intended to be limited to the specific embodiments described herein.

[0020] Example implementation of a multi-stage braking and deceleration system for work vehicles

[0021] Initially, refer to Figure 1 The illustration shows a work vehicle 10 that can implement embodiments of the invention. In the illustrated example, the work vehicle 10 is an articulated dump truck, but it should be understood that other vehicle configurations may be possible, including configurations of the work vehicle 10 as different types of off-highway vehicles. The work vehicle 10 includes a chassis or frame 12, a cab section 14, and a trailer section 16 mounted on the chassis or frame 12. The cab section 14 includes a cab 18 in which an operator can sit during operation of the vehicle 10. A front wheel assembly 20 supports the cab section 14 and is operatively coupled to the frame 12. The trailer section 16 includes a tilting body or cargo box 22 supported by the frame 12, wherein the cargo box 22 defines a container capable of receiving a payload. One or more actuators, such as hydraulic cylinders 24, may be coupled to the cargo box 22 to lift the cargo box 22 at an angle relative to the frame 12. The rear wheel assembly 26 supports the trailer section 16 and is operatively connected to the frame 12, wherein the rear wheel assembly 26 includes two sets of wheels 28, 30.

[0022] The work vehicle includes a controller 32 (or multiple controllers) to control the operation of various aspects of the work vehicle 10. Typically, the controller 32 (or other controller) can be configured as a computing system with an associated processor device 32A and memory architecture 32B, a hard-wired computing circuit (or multiple hard-wired computing circuits), programmable circuitry, a hydraulic, electrical, or electro-hydraulic controller, or others. Thus, the controller 32 can be configured to perform various computational and control functions relative to the work vehicle 10. In some embodiments, the controller 32 can be configured to receive input signals of various formats (e.g., hydraulic signals, voltage signals, current signals, etc.) and output command signals of various formats (e.g., hydraulic signals, voltage signals, current signals, mechanical movement, etc.).

[0023] The controller 32 can communicate electronically, hydraulically, mechanically, or otherwise with various other systems or devices within the work vehicle 10. For example, the controller 32 can communicate electronically or hydraulically with various actuators, sensors, and other devices (including those described below) inside (or outside) the work vehicle 10. The controller 32 can communicate with other systems or devices (including other controllers) in various known ways, including via the work vehicle 10's CAN bus (not shown), via wireless communication devices, hydraulic connections, or others. Figure 1 The example location of controller 32 is depicted; however, it is possible to understand other locations on the work vehicle 10.

[0024] In some embodiments, the controller 32 may be configured to receive input commands and interact with the operator via a human-vehicle interface 34, which may be located within the cab 18 of the work vehicle 10 for easy operator access. The human-vehicle interface 34 can be configured in various ways. In some embodiments, the human-vehicle interface 34 may include an input device 36 having one or more joysticks, various switches or levers, one or more buttons, a touchscreen interface that can be overlaid on a display, a keyboard, or various other human-machine interface devices.

[0025] As described in more detail below, as part of the operation of the control system 40 that implements a multi-stage braking and deceleration scheme in vehicle 10, controller 32 facilitates: inputting various types of operator commands; and collecting various types of vehicle operating parameter data associated with the work vehicle 10, wherein the control system 40 is understood to include controller 32 and multiple energy storage and dissipation devices in the work vehicle 10, and wherein aspects of the control system 40 are implemented on / by controller 32. As indicated above, operator commands can be input to controller 32 via human-vehicle interface 34, and vehicle operating parameter data can be in the form of raw data from applicable sensors (or other sources) described below, or undergo some processing in controller 32 to extract desired characteristics. The inputs and data received by controller 32 are utilized by control system 40 to provide braking and deceleration control in work vehicle 10 via various energy storage and dissipation devices in work vehicle 10, further details of which will be provided below.

[0026] The work vehicle 10 includes a propulsion source, which, in an example embodiment, is provided as a hybrid electric drive system comprising an engine 42 and one or more electric motors 47, 49. The engine 42 and the electric motors 47, 49 can supply power to the transmission 44.

[0027] In one example, engine 42 is an internal combustion engine such as a diesel engine, which is controlled by controller 32 to, for example, allow engine 42 to start, allow engine 42 to shut down, disable engine 42, and / or modify some aspect of the operation of engine 42 or associated systems, based on input received from human-vehicle interface 34. The work vehicle 10 may include an engine speed sensor 46 configured to determine the speed of engine 42 during operation.

[0028] In one example, motors 47 and 49 are AC motors such as permanent magnet AC motors or induction motors. In one implementation, and as will be... Figure 2 As described in more detail, the first motor 47 can receive mechanical power from the engine 42 and convert that power into electricity, wherein the electricity from the first motor 47 is then provided to the second motor 49. This electricity can then be converted again by the second motor 49 for mechanical output. The motors 47 and 49 can be controlled by the controller 32 to control their speed and operating mode, wherein the motors 47 and 49 can operate both in "electric motor mode" to convert electrical energy into mechanical energy and in "regenerative mode" to convert mechanical energy into electrical energy.

[0029] The transmission 44 transmits power from the engine 42 and / or the electric motors 47, 49 to a suitable drivetrain (not shown) coupled to the driven wheels of the work vehicle 10 to enable the work vehicle 10 to move. These driven wheels may include a front wheel assembly 20 and / or a rear wheel assembly 26. See below for reference. Figure 2 As described in more detail below, the transmission 44 can be configured as a hybrid electric transmission or eIVT, which combines the outputs of both the engine 42 and the motors 47, 49 to provide the final power transmission (e.g., to the vehicle axles), further details of which will be provided below. The transmission 44 may include sensors 48 that measure one or more characteristics of the transmission 44, such as transmission output speed, transmission gear ratio, and transmission fluid temperature. In one example, as part of a multi-stage braking and deceleration scheme implemented by the control system 40, the controller 32 controls the transmission 44 to allow or prohibit movement of the work vehicle 10, for example, based on input received from the human-vehicle interface 34.

[0030] The work vehicle 10 may also include a lubrication system 50 associated with the engine 42 and / or other parts of the work vehicle 10. The lubrication system 50 can be controlled based on signals from the controller 32 to circulate a liquid lubricant (e.g., oil) around the engine 42 (e.g., pistons, cylinders, bearings) and / or to circulate a liquid lubricant (e.g., oil) to other components of the work vehicle 10, such as the axle 52 of the vehicle 10. Although not shown in detail, the lubrication system 50 may include components such as oil tanks, conduits, and pumps to circulate lubricant in and out of the engine 42 and other applicable components. In one example, the lubrication system 50 may include one or more sensors 54 to measure one or more lubrication system characteristics. In one example, the sensor 54 may include a temperature sensor to measure the temperature of the lubricant at one or more locations within the lubrication system 50, such as the oil temperature at the axle 52. In one embodiment, the controller 32 may receive temperature readings from the sensor 54 and may control the lubrication system 50 and / or modify the operation of the control system 40 based on these temperature readings.

[0031] The work vehicle 10 may also include an energy storage device 56 electrically connected to other electrical components in the vehicle via a DC bus 58. The energy storage device 56 may be configured as a high-voltage or high-power energy storage device, and according to one example, may be a battery or battery pack, such that the energy storage device will hereinafter be referred to as "battery assembly 56". The battery assembly 56 can supply power to various components of the work vehicle 10 and may also receive recharge power, for example, from components such as motors 47, 49. The battery assembly 56 can be considered to have a state of charge (SOC) representing the amount of power that the battery assembly 56 can provide at a given time. The SOC can be affected by a variety of factors, including battery usage and temperature. Typically, the battery assembly 56 is recharged when the engine 42 is operating. At a given time, the SOC can be measured or otherwise determined by a battery sensor 60, which provides appropriate signals to the controller 32 of the control system 40. The controller 32 can control the battery assembly 56 based on commands from the operator via the human-vehicle interface 34 and / or based on readings acquired by the battery sensor 60.

[0032] The work vehicle 10 also includes additional braking and deceleration components that operate upon actuation / start to absorb and dissipate energy to slow the work vehicle 10. As an example, the work vehicle may include an axle service brake 64 and an engine brake 66 (e.g., an exhaust brake, a Jake brake) that can be used to slow the work vehicle 10. A braking resistor 68 (and associated chopper 69) may also be provided in the work vehicle 10 to provide deceleration, wherein the chopper 69 is turned off to switch braking energy to the braking resistor 68, which then functions to convert the braking energy into heat, thereby dissipating the energy and slowing the movement of the work vehicle 10. For example, the braking and deceleration components indicated above can be actuated by commands from the controller 32 based on inputs received from the human-vehicle interface 34 and from various sensors in the work vehicle 10. In one example, the axle service brake 64, the engine brake 66, and / or the braking resistor 68 can be activated by a braking torque command from the controller 32. One or more brake sensors 70 can be set to collect information associated with the axle brake 64, such as the temperature of the axle brake 64.

[0033] The work vehicle 10 may also include other components that can draw power from the vehicle. As a non-limiting example, these components may include a vehicle cooling fan 72 and engine accessories, generally indicated by 74, such as an alternator and an HVAC compressor. The vehicle cooling fan 72 and engine accessory 74 may be operated based on signals from the controller 32 and / or the control system 40.

[0034] Additional sensors can be provided to observe various conditions associated with the work vehicle 10. For example, a cooling fan sensor 76 can be positioned above or near the vehicle's cooling fan 72 to measure its operating parameters, such as the cooling fan speed. Additionally, various sensors 78 can be used to monitor the condition of the aforementioned engine accessory 74. Furthermore, the work vehicle 10 may include one or more voltage sensors 80 to measure the current (i.e., the inverter DC bus voltage) on the work vehicle 10's DC bus.

[0035] Based on the various components and features of the work vehicle 10 as described above, a multi-stage braking and deceleration scheme can be implemented in the work vehicle 10. The control system 40 can be operated to selectively store and dissipate energy generated by the movement of the work vehicle 10 during operation (especially during vehicle deceleration and / or when the vehicle is descending a steep slope). According to the graded or prioritized energy distribution scheme implemented by the controller 32, energy is distributed among the multiple energy storage, braking, and deceleration components (described above) in the work vehicle to maximize the use of the energy and minimize component wear that may result from braking and deceleration actions. In the work vehicle, braking and deceleration are achieved by using a control system 40 instead of a fluid reducer to distribute energy from the work vehicle among multiple energy-absorbing components in a braking and deceleration system 82. The braking and deceleration system 82 is characterized by including various energy storage, braking, and deceleration components, such as a battery pack 56, a braking resistor 68, an engine brake 66, an axle brake 64, a vehicle cooling fan 72, engine accessories 74 (alternator, HVAC compressor, etc.), transmission braking via a transmission 44, and / or engine friction within the engine 42. The control system 40 employs a multi-stage braking and deceleration scheme to slow the movement of the work vehicle 10 in response to a braking torque command requested by the operator, wherein the control system 40 selectively distributes energy to various energy-absorbing components within the work vehicle.

[0036] Reference Figure 2 An example of a hybrid electric drive system or transmission 84 included in a work vehicle 10 is illustrated, providing a more detailed discussion of the structure and arrangement of the engine 42, motors 47, 49, and transmission 44 of the work vehicle 10, and how the transmission 44 operates. The transmission 44 can be operated to provide transmission braking to dissipate energy (as part of a multi-stage braking and deceleration scheme implemented by the control system 40) to dissipate vehicle energy during dynamic events (such as when the work vehicle 10 is traveling downhill) so that the vehicle's engine slows down at a desired rate. According to the disclosure below, the transmission 44 can be operated to engage a "4-squaring" clutch to dissipate energy in the work vehicle 10, where this energy is consumed by existing transmission hardware. The operation of the transmission 44 and the entire transmission system 84 providing transmission clutch braking is more fully disclosed in U.S. Publication No. 2020 / 0309258, which is jointly owned by the assignees of this application and incorporated herein by reference. However, it should be recognized that... Figure 2 The transmission system 84 illustrated herein and described below is merely an example, and transmission braking can be provided by transmissions with different arrangements or configurations, and the particular transmission 44 described below does not limit the implementation of the invention in this respect.

[0037] In the illustrated embodiment, the drivetrain 84 includes a motor 42, a first motor 47, and a second motor 49. The first motor 47 and the second motor 49 can be connected via an electrical conduit 90. A power inverter 92 may be included, and the power inverter 92 may be operatively connected to the first motor 47 and / or the second motor 49. In some embodiments, the power inverter 92 may supply energy to and / or receive energy from the battery assembly 56. Additionally, the power inverter 92 may supply energy to and / or receive energy from the drivetrain 84. Furthermore, in some embodiments, the power inverter 92 may supply power to an external ground for machinery and / or another external energy device (not shown).

[0038] The transmission 44 transmits power from the engine 42, the first motor 47, and / or the second motor 49 to the output shaft 94. As described below, the transmission 44 includes multiple gear assemblies, clutches, and control components to appropriately drive the output shaft 94 at different speeds in multiple directions. Typically, in one example, the transmission 44 of the drivetrain 84 can be any type of electric continuously variable transmission (eIVT) arrangement, where it is recognized that… Figure 2 An alternative to the transmission illustrated herein may be included in the transmission system 84.

[0039] Engine 42 can, based on desired operation and commands from controller 32, provide rotational power to engine shaft 96 via engine output elements (such as a flywheel). Shaft 96 can be configured to provide rotational power to gear 98. Gear 98 can mesh with gear 100, which can be supported on (e.g., fixed to) shaft 102. Shaft 102 can be substantially parallel to and spaced from engine shaft 96. Shaft 102 can support various components of drivetrain 84, as will be discussed in detail.

[0040] Gear 98 can also mesh with gear 104, which is supported on (e.g., fixed to) shaft 106. Shaft 106 can be substantially parallel to engine shaft 96 and separated from engine shaft 130, and shaft 106 can be connected to first motor 47. Therefore, mechanical power from the engine (i.e., engine power) can be transmitted via engine shaft 96 to the meshing gears 98 and 104, to shaft 106, and to first motor 47. First motor 47 can convert this power into electricity for transmission through conduit 90 to second motor 49. This converted power can then be converted again by second motor 49 for mechanical output along shaft 108. Various known control devices (not shown) can be provided to regulate this conversion, transmission, and re-conversion, etc. Additionally, in some embodiments, shaft 108 can support gear 110 (or other similar components). Gear 110 can mesh with gear 112 and can transmit power to gear 112. Gear 110 can also mesh with gear 114 and can transmit power to gear 114. Therefore, the power from the second motor 49 (i.e., CVP power) can be distributed between gear 112 and gear 114 to transmit to other components, as will be discussed in more detail below.

[0041] The drivetrain 84 may also include a converter 116, which represents an example of an arrangement enabling continuously variable power transmission between the engine 42 and the motors 47, 49 and the output shaft 94. As discussed below, this arrangement also enables the transmission 44 to perform transmission clutch braking, in which excess energy is dissipated through a combination of transferring at least a portion of the energy back to the engine 42 and transferring a portion to the clutch brake. However, other arrangements of the converter 116, engine 42, and motors 47, 49 may be provided.

[0042] In some embodiments, the transducer 116 may include at least two planetary gear sets. In some embodiments, the planetary gear sets may be interconnected and supported on a common shaft such as shaft 102, and the planetary gear sets may be substantially concentric. In other embodiments, different planetary gear sets may be supported on separate, respective non-concentric shafts. The arrangement of the planetary gear sets can be configured based on the available space within the vehicle 10 for enclosing the drivetrain 84.

[0043] like Figure 2As shown in the embodiment, the transducer 116 may include a first planetary gear set (i.e., a "low" planetary gear set) having a first sun gear 118, a first planetary gear, an associated carrier 120, and a first ring gear 122. Furthermore, the transducer 116 may include a second planetary gear set (i.e., a "high" planetary gear set) having a second sun gear 124, a second planetary gear, an associated carrier 126, and a second ring gear 128. The second planetary gear and carrier 126 may be directly attached to the first ring gear 122. Additionally, the second planetary gear and carrier 126 may be directly attached to a shaft 130, on which a gear 132 is fixed. Furthermore, the second ring gear 128 may be directly attached to a gear 134. As shown, the shaft 130, gear 132, and gear 134 may each receive a shaft 102 and may be substantially concentric with the shaft 102. Although not specifically shown, it should be understood that the transmission system 84 may include various bearings for concentrically supporting these components. Specifically, shaft 130 can be rotatably attached to shaft 102 via a bearing, and gear 134 can be rotatably attached to shaft 130 via another bearing.

[0044] On the opposite side of converter 116 ( Figure 2 On the shaft 102 (from left to right), gear 114 can be mounted (e.g., fixed) on shaft 136, which also supports a first sun gear 118 and a second sun gear 124. In some embodiments, shaft 136 may be hollow and may receive shaft 102. Bearings (not shown) may rotatably support shaft 136 on shaft 102 in a substantially concentric manner.

[0045] Furthermore, the first planetary gear and associated bracket 120 can be attached to gear 138. Gear 138 can mesh with gear 140 fixed to shaft 142. Shaft 142 can be substantially parallel to and separated from shaft 102.

[0046] As described above, the drivetrain 84 can be configured to transmit power (from the engine 42, the first motor 47, and / or the second motor 49) via the transmission 44 to the output shaft 94. The output shaft 94 can be configured to transmit the received power to the wheels of the vehicle 10.

[0047] The drivetrain 84 can have multiple selectable modes, such as direct drive mode, split mode, and series mode. In direct drive mode, power from engine 42 can be transmitted to output shaft 94, and power from second motor 49 can be prevented from being transmitted to output shaft 94. In split mode, power from engine 4 and power from second motor 49 can be added by converter 116, and the added or combined power can be transmitted to output shaft 94. Furthermore, in series mode, power from second motor 49 can be transmitted to output shaft 94, and power from engine 42 can be prevented from being transmitted to output shaft 94. The drivetrain 84 can also have different speed modes in one or more of the direct drive, split, and series modes, and these different speed modes can provide different angular velocity ranges for output shaft 94. The drivetrain 84 can switch between multiple modes to maintain appropriate operating efficiency. In addition, the drivetrain 84 can have one or more forward modes for moving vehicle 10 in a forward orientation and one or more reverse modes for moving vehicle 10 in a reverse orientation.

[0048] The drivetrain 84 can be switched between different modes, for example, using a control assembly 144. The control assembly 144 may include one or more selectable transmission components. The selectable transmission components may have a first position (engaged position), in which corresponding means transmit power from an input component to an output component. The selectable transmission components may also have a second position (disengaged position), in which means prevent power transmission from the input to the output component. The selectable transmission components of the control assembly 144 may include one or more wet clutches, dry clutches, ring gear clutches, brakes, synchronizers, or other similar means. The control assembly 144 may also include actuators for actuating the selectable transmission components between the first and second positions.

[0049] like Figure 2As shown, control assembly 144 may include a first clutch 146, a second clutch 148, a third clutch 150, a fourth clutch 152, and a fifth clutch 154. Additionally, control assembly 144 may include a forward-oriented clutch 156 and a reverse-oriented clutch 158. In some embodiments, the first clutch 146 may be mounted and supported on shaft 160. Furthermore, in the engaged position, the first clutch 146 may engage gear 112 with shaft 160 for rotation as a unit. In the disengaged position, the first clutch 146 may allow gear 112 to rotate relative to shaft 160. Additionally, gear 162 may be fixed to shaft 160, and gear 162 may mesh with gear 132 fixed to shaft 130. The reverse-oriented clutch 158 may be supported on shaft 160 (i.e., supported on shaft 160 together with the first clutch 146). The reverse-oriented clutch 158 may engage gears 162 and 164, and alternatively disengage gears 162 and 164. Gear 164 can mesh with idler gear 166, and idler gear 166 can mesh with gear 168. A forward-oriented clutch 156 can be supported on gear 168 (gear 168 in turn is supported on shaft 102) to selectively engage shafts 130 and 102. Therefore, the forward-oriented clutch 156 can be concentric with both shafts 130 and 102. A second clutch 148 can be supported on shaft 142. The second clutch 148 can engage shaft 142 and gear 170, and alternatively disengage shaft 180 and gear 208. Gear 170 can mesh with gear 172. Gear 172 can be fixed to and mounted on a countershaft 174. The countershaft 174 can also support gear 176. Gear 176 can mesh with gear 178 fixed to output shaft 94.

[0050] The third clutch 150 can be supported on shaft 180. Shaft 180 can be substantially parallel to shaft 142 and separated from shaft 142 by a certain distance. Additionally, gear 182 can be fixed to and supported by shaft 180. Gear 182 can mesh with gear 134, as shown. The third clutch 150 can engage gears 182 and 184, and alternatively disengage gears 182 and 184. Gear 184 can mesh with gear 172. The fourth clutch 152 can be supported on shaft 142 (commonly with the second clutch 148). The fourth clutch 152 can engage shaft 142 and gear 186, and alternatively disengage shaft 142 and gear 186. Gear 186 can mesh with gear 188 mounted and fixed to shaft 174. Additionally, the fifth clutch 154 can be supported on shaft 180 (commonly and concentrically with the third clutch 150). The fifth clutch 154 can engage shaft 180 and gear 190, and alternatively disengage shaft 180 and gear 190. Gear 190 can mesh with gear 188.

[0051] As previously indicated, based on the selective operation of the transmission, the drivetrain 84 can operate in multiple modes, including at least one split mode, a direct drive mode, and a series mode. In the split mode, power from engine 42 and power from one or more of motors 47, 49 are combined. In the direct drive mode, power is supplied only from engine 42. In the series mode, power is supplied only from motors 47, 49. As described above, controller 32 is coupled to control assembly 144 to control one or more actuators, resulting in control of the movement of one or more selective transmission components within transmission 44, including a first clutch 146, a second clutch 148, a third clutch 150, a fourth clutch 152, a fifth clutch 154, a forward-directing clutch 156, and a reverse clutch 158. Typically, controller 32 operates control assembly 144, as well as engine 42 and motors 47, 49, to achieve desired functions, such as providing the requested torque at output shaft 94 for overall control of work vehicle 10. This includes vehicle acceleration, stopping, starting, gear ratio changes, and direction changes.

[0052] In situations where it is desired to dissipate the energy of the work vehicle 10, the transmission 44 can also provide transmission braking (transmission clutch braking) during various aspects of operation. Specifically, during dynamic events, such as when the work vehicle 10 is descending a steep slope and thus experiences excessive energy, transmission braking can be utilized, and it is desired that the transmission braking applies negative torque to maintain or reduce vehicle speed, resulting in excess energy at the engine. As described in more detail below, transmission braking allows at least a portion of this energy to be applied via the directional clutches 156, 158 of the transmission 44 to reverse-drive the engine 42 at the flywheel, allowing internal losses (e.g., heat and friction) to dissipate at least a portion of the excess energy. However, if this energy causes the engine 42 to otherwise exceed a predetermined speed threshold, the controller 32 can command the engagement of the opposite directional clutches 158, 156 to further dissipate the energy via friction and heat losses at the directional clutches 158, 156. In practice, a “4-square” clutch arrangement can be selectively implemented based on engine speed to further slow the engine output shaft. The combination of engine reverse drive and engagement of the opposite-direction clutch can achieve sufficient energy dissipation without utilizing output-side clutch braking and / or in a manner independent of wheel braking.

[0053] During dynamic events, such as when the work vehicle 10 is descending a slope and the drivetrain 84 is in the forward-oriented mode or direct drive mode as described above, power from the engine 42 is transmitted from the engine shaft 96 via the forward-oriented clutch 156 and ultimately to the output shaft 94 via the described arrangement. Therefore, when the forward-oriented clutch 156 engages in these modes while the reverse-oriented clutch 158 engages, the reverse-oriented clutch 158 is operated to apply a counter-torque to slow the engine shaft 96. In other words, the reverse-oriented clutch 158 acts as a clutch brake within the drivetrain 84 on the engine shaft 96. In one example, the reverse-oriented clutch 158 functions as a clutch brake in these modes because the gear 164 on one side of the reverse-oriented clutch 158 is moving in the opposite direction to the gear 162 on the other side, and the engagement of the clutch elements of the reverse-oriented clutch 158 generates frictional resistance during rotation, which is then transmitted via the shaft 102 to the shaft 96 at the engine 42.

[0054] The controller 32 is used to selectively control the actuation of the forward-oriented clutch 156 and the reverse-oriented clutch 158 during different orientation modes of the operating vehicle to provide transmission braking. The controller 32 can generate commands for implementing transmission braking based on inputs from the engine speed sensor 46 and from a plurality of additional transmission sensors 192, 194, 196. Sensor 192 is operably associated with the input device 36 to receive selection of gear or operating mode from the input device 36, while sensor 194 is operably associated with the forward-oriented clutch 156 to identify the engagement state of clutch 156, and sensor 196 is operably associated with the reverse-oriented clutch 158 to identify the engagement state of clutch 158.

[0055] Now refer to Figure 3 The block diagram illustrates the operation of the control system 40 in implementing a multi-stage braking and deceleration scheme in the work vehicle 10, including the inputs to the control system 40 and the illustration of the components of the control system 40. Embodiments of the control system 40 according to this disclosure may include various inputs to the controller 32, various sub-modules or algorithms within the controller 32, and the activation of various energy-absorbing components within the work vehicle 10.

[0056] The inputs provided to the controller 32 can generally be divided into operator commands 200 and closed-loop control parameters 202. For example, operator commands 200 can be provided to the controller 32 via the human-vehicle interface 34 and input device 36 on the work vehicle 10. The operator commands 200 provided to the controller 32 may include an operator-requested braking torque 204 and an associated operator-requested deceleration rate 206. The operator provides the controller 32 with commands regarding the desired amount of braking torque and deceleration for slowing down and / or maintaining the vehicle speed when the work vehicle 10 is traveling downhill.

[0057] Closed-loop control parameters 202 can be provided to controller 32 via various sensors 46, 48, 54, 60, 70, 76, 78, 80, 192, 194, and 196 included in the work vehicle, as described above relative to... Figure 1 The description describes a system where sensors acquire readings or measurements of various operating parameters of the work vehicle 10 during operation. Control parameters 202 may include, but are not limited to, engine speed 208, vehicle cooling fan speed 210, axle oil temperature 212, transmission oil temperature 214, inverter DC bus voltage 216, engine accessory status 218, battery state of charge 220, transmission output speed 222, and transmission gear ratio 224. Therefore, control parameters 202 indicate the current state of various energy-absorbing components in the vehicle drivetrain 84 and the work vehicle 10, wherein the controller 32 analyzes control parameters 202 to determine the optimal way to distribute energy among those energy-absorbing components in the braking and deceleration system 82.

[0058] like Figure 3 As illustrated, controller 32 may include multiple submodules or algorithms that determine the optimal way to distribute energy among components in the braking and deceleration system 82 of the work vehicle 10. Controller 32 includes a submodule 226 that acts as a motion observer for the vehicle and transmission system, wherein submodule 226 observes the operation of transmission 44, including, for example, the speed of output shaft 94, in response to torque commands from an operator. For example, closed-loop control parameter inputs regarding engine speed 208, transmission gear ratio 224, and transmission output speed 222 may be provided to submodule 226.

[0059] The controller 32 also includes an engine protection submodule 228, which identifies the current operating state of the engine 42 and provides appropriate braking and deceleration within the work vehicle 10 to protect the engine. Closed-loop control parameter inputs regarding the engine speed 208 can be provided to the engine protection submodule 228 to monitor the current operating speed of the engine 42. The engine protection submodule 228 can then control the engine speed by selectively dissipating energy via desired components in the braking and deceleration system 82 of the work vehicle 10 to prevent engine overspeeding.

[0060] The controller 32 also includes an axle brake protection submodule 230, which monitors the temperature of the axle brake 64 and provides appropriate operational control schemes for the axle brake 64 to protect it. Closed-loop control parameter inputs regarding the axle oil temperature 212 and / or other aspects of the axle brake 64 can be provided to the axle brake protection submodule 230 to monitor the axle temperature. The axle brake protection submodule 230 can then prevent overheating of the axle brake 64 by selectively dissipating energy via desired components in the braking and deceleration system 82 of the work vehicle 10 (rather than the axle brake 64), and otherwise protect the axle brake 64.

[0061] The controller 32 also includes a transmission clutch protection submodule 232, which monitors the temperature of transmission clutches 156 and 158 and provides appropriate operational control schemes for the transmission 44 to protect the transmission clutches 156 and 158. Closed-loop control parameter inputs regarding transmission fluid temperature 214 and / or other aspects of the transmission 44 can be provided to the transmission clutch protection submodule 232 to monitor the temperature of the transmission clutches 156 and 158. The transmission clutch protection submodule 232 can then prevent overheating of the transmission clutches 156 and 158 by selectively dissipating energy via desired components in the braking and deceleration system 82 of the work vehicle 10 (rather than the transmission 64), and otherwise protect the transmission.

[0062] The controller 32 also includes a submodule 234 for energy absorption priority control, namely, a priority control submodule 234. Specifically, the priority control submodule 234 determines a hierarchy, based on which the energy generated by the operating vehicle 10 is allocated or divided among components in the braking and deceleration system 82. In determining the graded energy allocation scheme, the priority control submodule 234 receives various closed-loop control parameters 202 (such as those measured by associated sensors) and operator commands 200, and communicates with other submodules in the controller 32. The priority control submodule 234 evaluates these inputs and communications and identifies an energy allocation among the components in the braking and deceleration system 82 that will adequately absorb vehicle energy and in a manner that optimizes energy capture / storage and minimizes the use of worn components in the braking and deceleration system 82. The priority control submodule 234 outputs commands to various components in the braking and deceleration system 82 to direct energy to said components or otherwise actuate said components to absorb energy.

[0063] Now refer to Figure 4 According to this disclosure, a flowchart of a method 236 for providing multi-stage braking and deceleration in a work vehicle 10 is provided, such as a method that can be executed by a controller 32. Typically, method 236 is implemented during operation of the work vehicle 10 when braking or deceleration is required, for example, while the vehicle is advancing down a steep slope. As will be described in detail below, method 236 implements a graded energy distribution scheme for distributing energy when braking and deceleration are performed in the work vehicle 10, wherein energy is first distributed to energy storage devices in the work vehicle 10, then distributed to other energy-consuming accessories and non-wearing components on the work vehicle 10, and subsequently used by wearing components to dissipate remaining energy. Method 236 provides an example of a graded energy distribution scheme that can be implemented, but it should be recognized that other similar graded energy distribution schemes can be implemented to provide multi-stage braking and deceleration in the work vehicle 10, wherein different stages can be provided and / or wherein certain different combinations of energy-absorbing components in the work vehicle 10 are utilized.

[0064] Method 236 begins at step 238, in which the operator requests a braking torque for the work vehicle 10 to slow its movement. The requested braking torque may vary with the speed at which the work vehicle 10 is traveling, the weight of the vehicle (i.e., the weight of the payload carried by the vehicle), and / or the gradient of the slope the vehicle is traveling downhill, as these parameters will at least partially determine the amount of braking torque required.

[0065] In response to the required braking torque, in step 240, the controller 32 calculates the amount of deceleration power or energy that must be requested from various energy absorption components in the work vehicle 10 to satisfy the required braking torque; that is, the amount of energy that must be absorbed by the work vehicle 10 to satisfy the braking torque requirement. Additionally, in step 240, and in conjunction with calculating the amount of requested deceleration power, the controller 32 also sets initial torque commands for the motors 47 and 49 included in the work vehicle 10 to control the operation of the motors 47 and 49 during braking and deceleration in the work vehicle 10. The initial torque commands provided to the motors 47 and 49 are used to control the amount of power supplied back to the DC bus in the work vehicle 10 during braking and deceleration.

[0066] In the illustrated example, method 236 then proceeds to step 242, where it is determined whether any available charging capacity exists in battery assembly 56. Controller 32 may receive input from battery sensor 60 regarding the state of charge of battery assembly 56 to determine whether any charging capacity is available in battery assembly 56. If it is determined that charging capacity is available in battery assembly 56, method 236 proceeds to step 244, where battery power extraction is performed. In step 246, the amount of power extracted by battery assembly 56 is subtracted from the requested total deceleration power previously calculated in step 240 to output the remaining deceleration power that must still be absorbed by the braking and deceleration system 82 in the work vehicle 10, a value which is stored by controller 32 as method 236 continues.

[0067] While potential power extraction from battery assembly 56 is occurring, method 236 continues along a parallel track, wherein in step 248, it is determined whether the voltage on DC bus 58 is at a high level, where a high level of DC bus voltage is considered to indicate the presence of energy that needs to be further absorbed or slowed down by control system 40. In performing step 248, controller 32 may receive input from voltage sensor 80 regarding the DC bus voltage level, wherein, for example, the measured DC bus voltage is compared with a predetermined DC bus voltage threshold to determine whether the DC bus voltage is at a high level. If it is determined that the voltage on DC bus 58 is at a high level, further power is dissipated from DC bus 58 via the operation of braking resistor 68 (and braking chopper). That is, the braking chopper is first turned off in step 250, and then turned off in step 252, thereby causing power to be subsequently supplied to braking resistor 68. In step 252, the amount of power consumed by the braking resistor 68 is subtracted from the (remaining) deceleration power to be absorbed calculated in step 246 to output a modified amount of remaining deceleration power that must still be absorbed by the braking and deceleration system 82 in the work vehicle 10, wherein the modified value is stored by the controller 32 as method 236 continues.

[0068] After the power consumption provided by the braking resistor 68 in step 252, method 236 continues in step 254 to further determine whether the voltage on the DC bus 58 is still at a high level. Similarly, during step 254, the controller 32 can receive input from the voltage sensor 80 regarding the DC bus voltage level. If it is determined in step 254 that the voltage on the DC bus 58 is still at a high level, the controller 32 can be used to issue a reverse command, thereby reducing the braking torque requested for the work vehicle 10 by modifying the initial torque command provided to the motors 47, 49. The reverse command is used to reduce the amount of power that must be absorbed in the work vehicle 10 by reducing the amount of power provided to the DC bus 58 during the deceleration of the work vehicle 10. Therefore, in step 256, a torque reduction command is provided to motors 47 and 49, and in step 258, the power reduction associated with the torque reduction command is quantified and subtracted from the (remaining) deceleration power to be absorbed calculated previously in step 252, to output a modified amount of remaining deceleration power that must still be absorbed by the braking and deceleration system 82 in the work vehicle 10, wherein the modified value is stored by the controller 32 as method 236 continues.

[0069] While the DC voltage is monitored in step 254 and potentially modified via power reduction in steps 256 and 258, method 236 continues along a parallel track, wherein in step 260 it is determined whether the speed of engine 42 is at a high level, where a high level of engine speed is considered to be a speed that can be characterized as an overspeed condition or near an overspeed condition. During the execution of step 260, controller 32 can receive input regarding engine speed from engine speed sensor 46. If it is determined that the engine speed is at a high level, power is further dissipated in step 262 by modifying the operation of vehicle cooling fan 72 and / or directing additional energy to one or more engine attachments 74 on the work vehicle 10. That is, controller 32 may cause vehicle cooling fan 72 to operate at maximum speed to dissipate additional power and / or cause engine attachments 74 to draw additional power (e.g., cause HVAC compressor to draw increased power to provide additional vehicle cooling). During step 262, the controller 32 may receive input from sensors 76, 78 regarding the cooling fan speed and engine accessory status to determine the appropriate power consumption for the vehicle cooling fan 72 and engine accessory 74. In step 264, the amount of power consumed by the vehicle cooling fan 72 and / or engine accessory 74 is subtracted from the (residual) deceleration power to be absorbed previously calculated in step 258 to output a modified amount of residual deceleration power that must still be absorbed by the braking and deceleration system 82 in the work vehicle 10, wherein this modified value is stored by the controller 32 as method 236 continues.

[0070] As method 236 continues, in step 266 it is determined whether additional power still needs to be absorbed to meet the braking power required by the operator (i.e., whether the requested total deceleration power has been absorbed by the energy absorption components in the work vehicle 10).

[0071] If it is determined in step 266 that there is no remaining power requiring further braking and deceleration via control system 40, method 236 proceeds to step 268, where controller 32 provides final commands to motors 47 and 49 to control their operation. After step 268 is completed, method 236 is repeated in a subsequent program loop, in which controller 32 again checks or receives braking torque requests from the operator, calculates the requested deceleration power for the braking torque requests, and continues with the graded energy distribution scheme (steps 238-266) to distribute energy absorption among the multiple braking and deceleration components in the work vehicle 10.

[0072] If it is determined in step 266 that there is remaining power requiring further braking and deceleration via control system 40, method 236 proceeds to step 269, in which one or more of the engine brake 66 (e.g., exhaust brake, Jake brake) and axle brake 64 are activated or applied. The engine brake 66 and axle brake 64 may be applied as a function of the remaining power to be decelerated in the work vehicle 10, and particularly for the axle brake 64, also as a function of the heat capacity or temperature of the axle brake 64 (e.g., axle oil temperature measured by sensor 70). In one implementation, the application of the engine brake 66 may be preferred over the axle brake 64 because, compared to the axle brake 64, the engine brake 66 is identified as a non-wearing component that does not deteriorate in response to increased use. In step 270, the amount of power dissipated by the engine brake 66 and / or the axle brake 64 is subtracted from the (remaining) deceleration power to be absorbed calculated in step 264 to output a modified amount of remaining deceleration power that must still be absorbed by the braking and deceleration system 82 in the work vehicle 10, wherein the modified value is stored by the controller 32 as method 236 continues.

[0073] Method 236 proceeds to step 272, where it is determined whether additional power still needs to be absorbed to meet the braking power required by the operator (i.e., whether the requested total deceleration power has already been absorbed by the energy absorption components in the work vehicle 10). If there is no remaining power required for further braking and acceleration via control system 40, method 236 proceeds by performing step 268 as previously described. Conversely, if it is determined in step 272 that there is remaining power required for further braking and deceleration via control system 40, method 236 proceeds to step 274, where transmission braking can be performed via selective actuation of clutches 156, 158 in transmission 44, as previously described relative to... Figure 2 Described. Transmission braking can be applied as a function of the remaining power to be decelerated in the work vehicle 10 and as a function of the heat capacity in the transmission (e.g., the transmission oil temperature measured by sensor 48).

[0074] After performing any necessary transmission braking, method 236 can further determine in step 276 whether the speed of engine 42 is still at a high level, i.e., at or near overspeed. During step 276, controller 32 can receive input regarding engine speed from sensor 46. If the engine speed is at an acceptable level, method 236 proceeds by performing step 268 as previously described. Conversely, if it is determined that the engine speed is still at a high level, controller 32 can be used to issue another reverse command in step 278, thereby reducing the braking torque requested by the work vehicle 10 by further modifying the torque commands provided to motors 47, 49, thereby reducing the amount of power that must be absorbed in the work vehicle 10.

[0075] After further reducing the torque command provided to motors 47 and 49 in step 278, method 236 proceeds to step 268, where the command modified in step 278 is provided to motors 47 and 49 as the final command. As previously described, after step 268 is completed, method 236 will be repeated in a subsequent program loop in which controller 32 will again check or receive the braking torque request from the operator, calculate the requested deceleration power for the braking torque request, and continue the graded energy distribution scheme (steps 238-268 or 238-278) to distribute energy absorption among the multiple braking and deceleration components in the work vehicle 10.

[0076] Therefore, this control system 40 provides an efficient method for providing braking and deceleration in the work vehicle 10 according to a graded energy distribution scheme. In one example, the control system 40 may sequentially distribute energy to the battery assembly 56, braking resistor 68, vehicle cooling fan 72 (and engine accessory 74), engine brake 66, axle brake 64, and transmission clutches 156, 158 to store and dissipate excess energy in the work vehicle 10, such as when on steep slopes or carrying heavy payloads. Individually, and particularly in combination, these aspects of the control system 40 can eliminate the need for a fluid reducer in work vehicles with hybrid electric drive systems and minimize the use of axle brakes for slowing down the work vehicle 10.

[0077] Listed examples

[0078] The following examples are provided and numbered for easy reference.

[0079] 1. A control system is provided for providing multi-stage braking and deceleration in a work vehicle, the work vehicle including a hybrid electric drive system having an engine and one or more electric motors. The control system includes a braking and deceleration system configured to dissipate energy generated by the motion of the work vehicle, wherein the braking and deceleration system further includes a braking resistor, an engine brake, and a transmission operable to provide transmission braking. The control system also includes a controller including a processor and memory architecture, the controller being operatively connected to the hybrid electric drive system and the braking and deceleration system. The controller is configured to: receive a plurality of inputs, the plurality of inputs including a braking torque requirement from an operator and operating parameters of the hybrid electric drive system and the braking and deceleration system; determine the amount of energy absorbed in the work vehicle necessary to meet the braking torque requirement; and distribute the energy to be absorbed within the braking and deceleration system according to a graded energy distribution scheme, wherein the energy is distributed based on the determined energy absorption amount and the operating parameters of the hybrid electric drive system and the braking and deceleration system.

[0080] 2. The control system according to Example 1, wherein the braking and deceleration system further includes an energy storage device that can be charged by the energy generated by the movement of the working vehicle.

[0081] 3. The control system according to Example 2, wherein when allocating the energy according to the graded energy allocation scheme, the controller is configured to: perform a first energy deduction by supplying charging energy to the energy storage device, and after performing the first energy deduction, perform a second energy deduction by supplying energy to the braking resistor.

[0082] 4. The control system according to Example 3, wherein the controller is configured to: after performing the first energy reduction and the second energy reduction, measure the voltage on the DC bus connected to the braking resistor and the energy storage device; determine whether the voltage is higher than a DC bus voltage threshold; and when the voltage is higher than the DC bus voltage threshold, reduce the level of the braking torque requirement.

[0083] 5. The control system according to Example 3, wherein the braking and deceleration system further includes axle brakes and vehicle and engine accessories, the vehicle and engine accessories including one or more of an alternator, an HVAC compressor, and a vehicle cooling fan.

[0084] 6. The control system according to Example 5, wherein, when allocating the energy according to the graded energy distribution scheme, the controller is configured to: perform a third energy reduction by supplying energy to the vehicle and engine accessories after performing the second energy reduction; and perform a fourth energy reduction by dissipating actuation energy via the engine brake and the axle brake after performing the third energy reduction.

[0085] 7. The control system according to Example 6, wherein, when allocating the energy according to the graded energy allocation scheme, the controller is configured to perform a fifth energy reduction by controlling the transmission to perform transmission braking after performing the fourth energy reduction.

[0086] 8. The control system according to Example 7, wherein the transmission includes a continuously variable transmission (CVT) configured to selectively transmit power from one or both of the engine and the one or more electric motors to the output shaft, and wherein the CVT performs transmission braking by selectively engaging a plurality of clutches in the CVT.

[0087] 9. The control system according to Example 3, wherein the controller is configured to: determine whether the energy storage device has any available charging capacity; when available charging capacity exists, perform the first energy deduction by providing charging energy to the energy storage device; and if no available charging capacity exists, skip the first energy deduction.

[0088] 10. The control system according to Example 2, wherein the operating parameters include at least some of engine speed, axle oil temperature, transmission oil temperature, DC bus voltage, state of charge of energy storage device, transmission output speed, transmission gear ratio, engine accessory status, and cooling fan speed.

[0089] 11. The control system according to Example 1, wherein allocating the energy to be absorbed according to the graded energy distribution scheme provides overspeed protection for the engine.

[0090] 12. The control system according to Example 1, wherein the hierarchical energy allocation scheme is an iterative control scheme, wherein the controller executes multiple program loops.

[0091] 13. A work vehicle includes a drivetrain comprising an engine, one or more electric motors, and a transmission, the transmission being configured to selectively transmit power from at least one of the engine and the one or more electric motors to an output shaft. The work vehicle further includes a braking and deceleration system configured to dissipate energy generated by the motion of the work vehicle, wherein the braking and deceleration system has a braking resistor, an engine brake, and transmission braking provided by the transmission. The work vehicle also includes a controller comprising a processor and a memory architecture, the controller communicating with the drivetrain and the braking and deceleration system. The controller is configured to: receive a plurality of inputs, the plurality of inputs including a braking torque requirement from an operator and operating parameters of the drivetrain and the braking and deceleration system; determine the amount of energy absorbed in the work vehicle necessary to meet the braking torque requirement; and distribute the energy to be absorbed within the braking and deceleration system according to a tiered energy distribution scheme, wherein the energy is distributed based on the determined energy absorption amount and the operating parameters of the drivetrain and the braking and deceleration system.

[0092] 14. The work vehicle according to Example 13, wherein the braking and deceleration system further includes an energy storage device configured to draw power as part of the tiered energy storage scheme.

[0093] 15. The work vehicle according to Example 14, wherein, when allocating the energy according to the graded energy allocation scheme, the controller is configured to assign the highest priority to the stored energy and the second highest priority to the non-wearing components engaging the braking and deceleration system to dissipate the energy.

[0094] in conclusion

[0095] Therefore, the above provides a control system for providing multi-stage braking and deceleration in a work vehicle including a hybrid electric drive system. This control system implements a graded energy distribution scheme to selectively store and dissipate energy generated by the motion of the work vehicle. The control system distributes energy among multiple energy storage, braking, and deceleration components within the work vehicle. The graded energy distribution scheme prioritizes energy allocation among energy storage, braking, and deceleration components to maximize energy utilization and minimize component wear that may result from braking and deceleration actions. Instead of using a fluid decelerator, braking and deceleration are achieved in the work vehicle using a control system that distributes energy from the work vehicle among multiple energy-absorbing components while also dissipating energy via engine friction and transmission braking. These energy-absorbing components may include battery packs, braking resistors, engine brakes, axle brakes, cooling fans, and other engine accessories.

[0096] As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprise” and / or “comprising” specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0097] The description of this disclosure has been shown for illustrative and descriptive purposes, but it is not intended to be exclusive or limited to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments explicitly referenced herein have been selected and described in order to best explain the principles of this disclosure and its practical application, and to enable others skilled in the art to understand this disclosure and identify alternatives, modifications, and variations of the described examples. Therefore, various embodiments and implementations other than those explicitly described are within the scope of the following claims.

Claims

1. A control system (40) for providing multi-stage braking and deceleration in a work vehicle (10), the work vehicle (10) comprising a hybrid electric drive system (84) having an engine (42) and one or more electric motors (47, 49), the control system (40) comprising: A braking and deceleration system (82) configured to dissipate energy generated by the motion of the work vehicle (10), the braking and deceleration system (82) including a braking resistor (68), an engine brake (66), and transmission braking provided by the transmission (44) of the work vehicle (10); and A controller (32), comprising a processor (32A) and a memory architecture (32B), is operatively connected to the hybrid electric drive system (84) and the braking and deceleration system (82), and is configured to: Receive multiple inputs, including braking torque requirements from the operator and operating parameters of the hybrid electric drive system (84) and the braking and deceleration system (82); Determine the amount of energy absorbed by the work vehicle (10) necessary to meet the braking torque requirement; and The energy to be absorbed is distributed within the braking and deceleration system (82) according to a graded energy distribution scheme, wherein the energy is distributed based on the determined energy absorption amount and the operating parameters of the hybrid electric drive system (84) and the braking and deceleration system (82). The braking and deceleration system (82) further includes an energy storage device (56), which can be charged by the energy generated by the movement of the work vehicle (10). When allocating energy according to the graded energy allocation scheme, the controller (32) is configured as follows: The first energy deduction is performed by supplying charging energy to the energy storage device (56); and After performing the first energy reduction, a second energy reduction is performed by supplying energy to the braking resistor (68), and The controller (32) is configured as follows: After performing the first energy reduction and the second energy reduction, the voltage on the DC bus (58) in the work vehicle (10) is measured, the DC bus (58) being electrically connected to the braking resistor (68) and the energy storage device (56). Determine whether the voltage is higher than the DC bus voltage threshold; and When the voltage is higher than the DC bus voltage threshold, the level of the braking torque requirement is reduced.

2. The control system (40) according to claim 1, wherein, The braking and deceleration system (82) also includes axle brakes (64) and engine accessories (74), the engine accessories (74) including one or more of an alternator, an HVAC compressor and a vehicle cooling fan.

3. The control system (40) according to claim 2, wherein, When allocating the energy according to the graded energy allocation scheme, the controller (32) is configured to: After performing the second energy reduction, a third energy reduction is performed by supplying energy to the engine accessory (74); and After the third energy reduction is performed, the fourth energy reduction is performed by dissipating the energy via the actuation of the engine brake (66) and the axle brake (64).

4. The control system (40) according to claim 3, wherein, When allocating energy according to the graded energy allocation scheme, the controller (32) is configured to perform a fifth energy reduction by controlling the transmission (44) to perform transmission braking after the fourth energy reduction is performed.

5. The control system (40) according to claim 4, wherein, The transmission (44) includes a continuously variable transmission (CVT) configured to selectively transmit power from one or both of the engine (42) and the one or more electric motors (47, 49) to the output shaft (94), and wherein the CVT performs transmission braking by selectively engaging a plurality of clutches in the CVT.

6. The control system (40) according to claim 1, wherein, The controller (32) is configured to determine whether the energy storage device (56) has any available charging capacity; When available charging capacity is available, the first energy subtraction is performed by supplying charging energy to the energy storage device (56); and If no available charging capacity is available, skip the first energy deduction.

7. The control system (40) according to claim 1, wherein, The operating parameters include at least some of the following: engine speed, axle oil temperature, transmission oil temperature, DC bus voltage, state of charge of energy storage device, transmission output speed, transmission gear ratio, engine accessory status, and cooling fan speed.

8. The control system (40) according to claim 1, wherein, The energy to be absorbed is allocated according to the graded energy distribution scheme to provide overspeed protection for the engine (42).

9. The control system (40) according to claim 1, wherein, The graded energy allocation scheme is an iterative control scheme, wherein the controller (32) executes multiple program loops.

10. A work vehicle (10), said work vehicle (10) comprising: A drivetrain (84) comprising an engine (42), one or more electric motors (47, 49), and a transmission (44) for selectively transmitting power from at least one of the engine (42) and the one or more electric motors (47, 49) to an output shaft (94); and The control system (40) according to any one of claims 1 to 9.

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