CONTROL OF TRANSITIONS BETWEEN GEARBOX STATES

Abstract

System for controlling a transmission state of a vehicle (10), comprising: a control unit (52) connected to a first drive system (20) and a first transmission, wherein the first drive system (20) comprises an electric motor (22), and the first transmission comprises a gear system, a first clutch (112) and a second clutch (114); a carrier (104) rotatably coupled to the electric motor (22), and comprising a plurality of planet gears (106), a sun gear (108) and a ring gear (110), wherein the ring gear (110) is rotatably coupled to an output of the transmission, and wherein the first clutch (112) can be actuated to immobilize the sun gear (108), and the second clutch (114) can be actuated to rotatably couple the electric motor (22) and the carrier (104) to the ring gear (110); wherein the control unit (52) is configured to perform: Receiving a request to change from an initial transmission state to a target transmission state when a drive torque is applied to the vehicle (10), wherein one is a moving-away clutch from the first clutch (112) and the second clutch (114) that is engaged with the gear system in the initial transmission state, and another is a moving-away clutch from the first clutch (112) and the second clutch (114) that is disengaged from the gear system in the initial transmission state; Distributing the drive torque so that the entire drive torque is supplied by a second drive system (30), and the first drive system (20) does not provide any drive torque for the vehicle (10); Complete release of the outgoing coupling from the gear system; Controlling engine speed based on a speed ratio of the target transmission state to reduce slippage speed of the approaching clutch; and Full engagement of the approaching clutch to bring the first drive system (20) into the target transmission state.

Description

INTRODUCTION

[0001] The subject matter of the disclosure relates to vehicles and, more particularly, to systems, devices, and methods for controlling vehicle transmissions.

[0002] Vehicles, including gasoline- and diesel-powered vehicles, as well as electric and hybrid electric vehicles, have battery storage to power electric motors, electronics, and other vehicle subsystems. Electric vehicles can be equipped with single-drive systems or multiple-drive systems that include two or more electric motors for torque transfer. For example, some vehicles include one drive system to control the torque applied to the rear wheels and another drive system to control the torque applied to the front wheels.

[0003] DE 10 2021 122 301 A1 discloses a method for operating a vehicle, comprising: shifting a first axle from a lower gear range to a high gear range while meeting a driver demand torque via a second axle, wherein the shifting comprises ramping down the torque of an electric machine of the first axle to a first positive threshold torque, disengaging the low gear range, setting the torque of the electric machine of the first axle to a negative torque in a predetermined period of time after the electric machine of the first axle reaches the first positive threshold torque, wherein the torque of the first electric machine of the first axle sets a slip speed of a clutch of the high gear range of the first axle, engaging a synchronizer in response thereto,that the slip speed of the high range clutch is within a threshold of zero slip, closing the high range clutch and increasing the torque of the electric machine after the high range clutch is closed., SUMMARY

[0004] In an exemplary embodiment, a system for controlling a transmission state of a vehicle includes a controller connected to a first drive system and a first transmission connected to the first drive system. The first drive system includes an electric motor, the first transmission includes a gear system, a first clutch, and a second clutch. The system further includes a carrier rotatably coupled to the electric motor and a plurality of planetary gears, a sun gear, and a ring gear, the ring gear rotatably coupled to an output of the transmission, and the first clutch operable to immobilize the sun gear and the second clutch operable to rotatably couple the electric motor and the carrier to the ring gear.The controller is configured to receive a request to change from an initial transmission state to a target transmission state when drive torque is applied to the vehicle, wherein one of the first clutch and the second clutch is an off-going clutch engaged with the gear system in the initial transmission state, and another of the first clutch and the second clutch is an on-coming clutch disengaged from the gear system in the initial transmission state.The controller is configured to distribute drive torque so that all drive torque is applied by a second drive system and the first drive system provides no drive torque to the vehicle, fully disengage an off-going clutch from the gear system, control an engine speed based on a speed relationship of the target transmission state to reduce a slip speed of the off-going clutch, and fully engage an on-coming clutch to place the first drive system in the target transmission state.

[0005] In addition to one or more of the features described herein, the controller is further configured to redistribute drive torque such that at least a portion of the drive torque is applied by the first drive system.

[0006] In addition to one or more of the features described herein, the controller is further configured to redistribute drive torque such that the second drive system does not provide drive torque to the vehicle, the second drive system is connected to a second transmission, and changes a transmission state of the second transmission from a first transmission state to a second transmission state.

[0007] In addition to one or more of the features described herein, the first transmission has a low gear state in which the first clutch is the off-going clutch and the second clutch is the on-coming clutch, and a high gear state in which the first clutch is the on-coming clutch and the second clutch is the off-going clutch.

[0008] In addition to one or more of the features described herein, the initial transmission state is the low gear state, and the target transmission state is the high gear state, and controlling the engine speed includes reducing the engine speed to match the engine speed with a speed of the ring gear.

[0009] In addition to one or more of the features described herein, the initial transmission state is the high gear state and the target transmission state is the low gear state, and controlling the engine speed includes increasing the engine speed based on the speed relationship of the low gear state.

[0010] In addition to one or more of the features described herein, the controller includes a first controller configured to control the speed of the electric motor and a second controller configured to control operation of the first transmission.

[0011] In addition to one or more of the features described herein, the system is configured to control the transmission state based on coordination between the first controller and the second controller.

[0012] In another exemplary embodiment, a method for controlling a transmission state of a vehicle includes receiving a request in a controller to change from an initial transmission state to a target transmission state when drive torque is applied to a vehicle, the controller is connected to a first drive system and a first transmission, the first drive system includes an electric motor, and the first transmission includes a gear system, a first clutch, and a second clutch.One of the first clutch and the second clutch is an off-going clutch that engages the gear system in the initial transmission state, and another of the first clutch and the second clutch is an on-coming clutch that disengages the gear system in the initial transmission state, wherein the gear system carries a carrier rotatably coupled to the electric motor and a plurality of planetary gears, a sun gear, and a ring gear rotatably coupled to an output of the transmission, and wherein the first clutch is operable to immobilize the sun gear and the second clutch is operable to rotatably couple the electric motor and the carrier to the ring gear.The method also includes distributing the drive torque so that all the drive torque is applied by a second drive system and the first drive system provides no drive torque to the vehicle, fully disengaging the off-going clutch from the gear system, controlling an engine speed based on a speed relationship of the target transmission state to reduce a slip speed of the on-coming clutch, and fully disengaging the on-coming clutch to place the first drive system in the target transmission state.

[0013] In addition to one or more of the features described herein, the method further comprises redistributing the drive torque such that at least a portion of the drive torque is applied by the first drive system.

[0014] In addition to one or more of the features described herein, the method further comprises redistributing drive torque such that the second drive system does not provide drive torque to the vehicle, the second drive system being connected to a second transmission, and changing a transmission state of the second transmission from a first transmission state to a second transmission state.

[0015] In addition to one or more of the features described herein, the first transmission has a low gear state in which the first clutch is the off-going clutch and the second clutch is the on-coming clutch, and a high gear state in which the first clutch is the on-coming clutch and the second clutch is the off-going clutch.

[0016] In addition to one or more of the features described herein, the initial transmission state is the low gear state, and the target transmission state is the high gear state, and controlling the engine speed includes reducing the engine speed to match the engine speed with a speed of the ring gear.

[0017] In addition to one or more of the features described herein, the initial transmission state is the high gear state and the target transmission state is the low gear state, and controlling the engine speed includes increasing the engine speed based on the speed relationship of the low gear state.

[0018] The above features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further features, advantages and details are listed only as examples in the following detailed description, which refers to the drawings, where: Fig. 1 is a plan view of a motor vehicle including a multiple propulsion system according to an exemplary embodiment; Fig. 2 shows an electric motor and a transmission system of a vehicle, the transmission system including a gear system and control devices for controlling the transmission system, according to an exemplary embodiment; Fig. 3 is a flowchart illustrating aspects of a method for controlling vehicle propulsion and controlling transitions between transmission states, according to an exemplary embodiment; Fig. 4A-4C schematically illustrate an electric motor and components of a transmission system and aspects of an application example for the method of Fig. 3 to shift up from a low gear state to a high gear state; Fig. 5A-5C schematically illustrate an electric motor and components of a transmission system and aspects of an application example for the method of Fig. 3 to downshift from a high gear state to a low gear state; and Fig. 6 shows a computer system according to an exemplary embodiment. DETAILED DESCRIPTION

[0020] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference characters designate like or corresponding parts and features.

[0021] According to exemplary embodiments, methods, apparatus, and systems are provided for controlling one or more transmission systems (i.e., transmissions) in a vehicle, such as an electric vehicle or hybrid vehicle. One embodiment of a method includes receiving a request to shift between transmission states (e.g., a low gear state and a high gear state) in a first propulsion system of a vehicle having multiple propulsion systems. Prior to the shift, drive torque (i.e., torque applied to propel the vehicle) is distributed to one or more other propulsion systems such that the first propulsion system provides no torque to the vehicle and the shift can be completed with zero or minimum torque.

[0022] After the torque is distributed, the shift is initiated by opening an engaged clutch (an "off-going clutch"), for example, by fully releasing or "dumping" the off-going clutch. Once the off-going clutch is fully disengaged, a speed matching process is performed in which the speed of an engine ("engine speed") in the driveline is controlled until the engine speed is matched to the transmission output speed, and a clutch to be engaged (an "on-coming clutch") has zero slip speed. The on-coming clutch is then fully engaged to place the first driveline in the desired transmission state.

[0023] In one embodiment, the method is repeated for each other drive system if the transmission state of the one or more other drive systems is to be changed by distributing torque away from a shifting drive system and performing a shift as described above. Other embodiments include performing the method by coordinating operations of various control units in a vehicle so that shifts can be completed quickly, efficiently, and smoothly.

[0024] The embodiments described herein offer numerous advantages and technical effects. The embodiments enable precise, coordinated clutch and motor control to increase efficiency and ride quality (e.g., smooth shifting). Furthermore, the embodiments simplify hardware designs, thus improving reliability. Further advantages include reductions in clutch wear.

[0025] The embodiments are not limited to use with a particular vehicle and may be applicable in various contexts. For example, the embodiments may be used in automobiles, trucks, aircraft, construction equipment, agricultural equipment, automated factory equipment, and / or any other device or system that includes a transmission. Although the embodiments are described in connection with a vehicle having two drive systems, they are also applicable to vehicles having a single electric drive system or having any number of drive systems.

[0026] Fig. 1 illustrates an embodiment of a motor vehicle 10 including a vehicle body 12 that at least partially defines a passenger compartment 14. The vehicle body 12 also supports various subsystems of the vehicle, including a propulsion system 16 and other subsystems for supporting functions of the propulsion system 16 and other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, and, if the vehicle is a hybrid electric vehicle, a fuel injection subsystem, an exhaust subsystem, and the like.

[0027] The vehicle 10 may be an electric vehicle (EV), a hybrid vehicle, or any other vehicle that has multiple electric motors or propulsion systems. In one embodiment, the vehicle 10 is an electric vehicle that includes multiple motors and / or propulsion systems. For example, the propulsion system 16 is a multiple propulsion system that includes a first propulsion system 20 and a second propulsion system 30. The first propulsion system 20 includes a first electric motor 22 (which may be embodied as a motor-generator unit, or MGU) and a first inverter 24, as well as other components such as a cooling system. The first propulsion system 20 may include one or more controllers, such as a motor control module 25 (also referred to as a motor control processor, or MCP 25).

[0028] The first drive system 20 is connected to a transmission system 26, which includes a gearbox 70 for controlling the transmission of torque from the first engine 22 to a drive shaft 28. The drive shaft is connected to the front wheels 29. The transmission system 26 may include one or more control modules, such as a transmission control module (TCM) 74.

[0029] The second drive system 30 includes a second electric motor 32 and a second inverter 34, as well as other components such as a cooling system. The second drive system 30 may include one or more controllers, such as an MCP 35. The second drive system 30 is connected to a transmission system 36, which includes a gearbox 72 for controlling the transmission of torque from the second motor 32 to the rear wheels 39 via a driveshaft 38. The transmission system 36 may also include one or more control units, such as a TCM 76.

[0030] The inverters 24 and 34 (e.g., traction inverters or TPIMs) each convert direct current (DC) from a high voltage (HV) battery pack 44 into multi-phase (e.g., two-phase, three-phase, six-phase, etc.) alternating current (AC) to drive the motors 22 and 32.

[0031] As in Fig. 1, the drive systems 20 and 30 are configured such that the first electric motor 22 drives the front wheels 29 and the second electric motor 32 drives the rear wheels 39. However, the embodiments are not so limited, as there may be any number of drive systems and / or motors in different locations (e.g., one motor for each wheel, two motors per axle, etc.). Furthermore, the embodiments are not limited to a dual drive system, as the embodiments may be used with a vehicle having any number of motors and / or inverters.

[0032] The drive system 20 and the drive system 30 are electrically connected to a battery system 40 and may also be electrically connected to other components such as the vehicle's electronics (e.g., via an auxiliary power module or APM 42). The battery system 40 may be configured as a rechargeable energy storage system (RESS).

[0033] In one embodiment, battery system 40 includes a battery assembly such as battery pack 44. Battery pack 44 includes a plurality of battery modules 46, each battery module 46 including a number of individual cells (not shown). Battery system 40 may also include a monitoring unit 48 configured to receive measurements from sensors 50. Each sensor 50 may be an assembly or system including one or more sensors for measuring various battery and environmental parameters, such as temperature, current, and voltages.

[0034] Any of various processing devices or control units may be used to control the drive and transmission systems. A control unit includes any suitable processing device or unit and may be a dedicated control unit, such as control unit 52.

[0035] In one embodiment, the methods described herein are performed by one or more existing controllers associated with each powertrain system. For example, aspects of shifting transmission system 26 may be performed by MCP 25 in coordination with TCM 74, and aspects of shifting transmission system 36 may be performed by MCP 35 in coordination with TCM 76.

[0036] The vehicle 10 also includes a computer system 62 that includes one or more processing devices 64 and a user interface 66. The computer system 62 may, for example, communicate with the controller 52 and / or other processor(s) to provide them with commands in response to user input. The various processing devices, modules, and units may communicate with each other via a communication device or system, such as a Controller Area Network (CAN) or Transmission Control Protocol (TCP) bus.

[0037] Fig. Figure 2 shows an example of the drive system 20 and the transmission system 26. In this example, the transmission system 26 includes a gear system configured to provide two gears or transmission states. Although only the drive system 20 and the transmission system 26 are illustrated, it should be understood that the drive system 30 (rear-wheel drive system) and the transmission system 36 include a similar gear system.

[0038] The embodiments are not limited to the Fig. 1 shown number of drive systems or the Fig. 2. For example, the vehicle 10 may have any number of drive systems and associated transmissions. Furthermore, the transmission systems are not limited to the transmission shown in Fig. 2, since the transmission systems may have more than two gear states and / or use any other suitable type of gear system or transmission (e.g. a dual clutch transmission (DCT) or another type of stepped transmission).

[0039] The motor 22 is connected to a motor shaft 80 and a motor shaft gear 82. The motor shaft gear 82 engages a transmission gear 84, which is connected to a transmission shaft 86. The torque of the motor 22 is transmitted to the transmission 26 via a clutch shaft 88, and the output torque of the transmission 26 is supplied to a transmission gear 90 and a drive gear 92 of the drive shaft 28.

[0040] The transmission 26 includes a planetary gear set 100 and a clutch system 102. The planetary gear set 100 includes a carrier 104 connected to the planetary gears 106, a sun gear 108, and a ring gear 110.

[0041] The clutch system 102 includes a first clutch 112 and a second clutch 114. It should be noted that although the transmission system of Fig. 2 is illustrated as having two clutches, the embodiments are not so limited and may have any number of clutches.

[0042] In this embodiment, clutches 112 and 114 are torque-transmitting clutches, which may be frictional clutches (e.g., hydraulically or electromechanically controlled) or mechanical clutches such as jaw clutches and / or selectable one-way clutches (SOWC). It should be noted that clutches 112 and 114 may each be of any suitable type.

[0043] The first clutch 112 (C1) controls a connection between the sun gear 108 and a fixed or immobile state. The first clutch 112 can transmit torque in only one direction (a "positive" direction) when a SOWC is used, or it can transmit torque in two directions (i.e., the positive direction and an opposite negative direction). During positive direction rotation, if the speed of the motor 22 is reduced or brought to zero, the first clutch 112 can continue to rotate, thus storing the rotational energy transmitted by the motor. The second clutch 114 engages or disengages the ring gear 110 with the carrier 104.

[0044] Planetary gear set 100 can operate to provide a range of gear ratios. In one embodiment, the gear set can operate between a first gear state having a first gear ratio and a second gear state having a second gear ratio.

[0045] For example, the first gear ratio is a non-uniform gear ratio (e.g., a "low gear ratio" of less than 1:1), while the second gear ratio is uniform (e.g., a "high gear ratio" of 1:1). The first gear ratio is established by engaging (closing) the first clutch 112 to ground the sun gear member 108, thereby immobilizing the sun gear member 108. The second clutch 114 is disengaged (open). The torque of the engine 22 is transmitted via the clutch shaft 88 to the carrier member 104 and then via the planetary gear members 106 to the ring gear member 110. The rotation of the ring gear member 110 is then transmitted to the transfer gear member 90 and the drive gear member 92. The torque is thus transmitted to the drive shaft 28.

[0046] To establish the second gear ratio, the first clutch 112 is opened (or held in an open position) and the second clutch 114 is engaged to lock the carrier 104 to the ring gear 110. The torque of the engine 22 is provided via the clutch shaft 88 to the carrier 104, from the carrier 104 to the ring gear 110, and then to the transfer gear 90 and the drive gear 92 to rotate the drive shaft and the wheels 29.

[0047] The drive system 20 and / or the transmission system 26 may include various sensors. For example, sensors may be used by the controller 52 (or controllers 25 and 74) to determine various operating parameters. Such sensors include, but are not limited to, a resolver 94 for determining engine position and / or engine speed, wheel speed sensors 96, and various torque and / or speed sensors 98 for estimating the speeds of components such as the ring gear 110, the clutch 112, and / or the clutch 114.

[0048] Fig. 3 illustrates embodiments of a method 120 for controlling a drive or drive system and for controlling transitions between transmission states of a drive system. Aspects of method 120 may be performed by one or more processors located within a vehicle, such as controller 52, or a combination of processors. For example, the method may be performed by MCP 25 in coordination with TCM 74.

[0049] The method 120 is used in connection with the vehicle 10 of Fig. 1 and the drive and transmission systems of Fig. 2. However, the method 120 is not so limited and may be used with any suitable vehicle having any number of drive systems and transmissions. Although the method is described as being initiated at the first drive system 20, the method 120 may also be initiated at the second drive system 30.

[0050] The method 120 includes a series of steps or stages represented by blocks 121-125. The method 120 is not limited in the number or order of the steps therein, as some of the steps represented by blocks 121-125 may be performed in a different order than described below, or fewer than all of the steps may be performed.

[0051] At block 121, a vehicle receives a request to transition a transmission connected to a first drive system, such as drive system 20, from an initial transmission state to a target transmission state (e.g., between a first and a second gear ratio). For example, a request is received at TCM 74 (e.g., from a vehicle control module) to shift the first transmission system 26 from a first gear to a second gear. The request may be an upshift command requesting the transmission system 26 to shift from a low gear to a high gear, or a downshift command requesting the transmission system 26 to shift from a high gear to the low gear.

[0052] In block 122, the entire drive torque load is distributed to one or more other drive systems such that the electric motor 22 in the first drive system 20 is in a torque-free mode in which the motor 22 does not provide drive torque to the vehicle. For example, the MCP 25 receives a request from the TCM 74 and treats the TCM request with the highest priority. The MCP 25 immediately (or as quickly as possible) coordinates with the second drive system 30 to distribute the drive torque from the first drive system 20 to the second drive system 30 such that the second drive system 30 provides all the drive torque and the electric motor 22 of the first drive system 20 provides no torque to the vehicle 10.

[0053] In block 123, the electric motor 22 of the first drive system 20 is placed in a torque-free mode and subsequently disengaged from the transmission (placed in a neutral state). A "zero torque" mode is a mode in which the requested or commanded torque is zero (i.e., a request or command has been sent to an engine controller or engine control unit to cause the engine to apply zero torque).

[0054] To place the engine 22 into the neutral state, an initially engaged clutch (the "off-going clutch") is disengaged. For example, if the initial transmission state is a low gear state in which the first clutch 112 is engaged and the second clutch 114 is disengaged, the first clutch 112 is the off-going clutch and is quickly and completely released ("dumped") so that both clutches are disengaged. If the initial transmission state is a high gear state in which the first clutch 112 is disengaged and the second clutch 114 is engaged, the second clutch 114 is the off-going clutch and is dumped.

[0055] In block 124, a speed matching process is performed by controlling the speed of the engine 22 (engine speed) to match the engine speed with an output speed of the transmission system 26. The engine speed is matched based on a speed relationship between the components of the transmission system 26 associated with the target transmission state. The engine speed may be controlled in steps to provide a smooth transition.

[0056] For example, when the target transmission state is the low gear state, the engine speed of the engine 22 is increased according to a speed relationship between the carrier 104, the ring gear 110 (and the output speed of the transmission 26), and the sun gear 108 associated with the low gear state. When the target transmission state is the high gear state, the engine speed is decreased to match the engine speed with the speed of the ring gear 110 (ring gear speed) such that the engine speed is equal to the ring gear speed or within a selected range of the ring gear speed.

[0057] In block 125, an initially disengaged clutch (i.e., the clutch that was disengaged in the initial transmission state, also referred to as an "on-coming clutch") is engaged to bring the transmission system 26 into the target transmission state. The on-coming clutch is engaged by applying a force until the clutch slip speed is zero.

[0058] In one embodiment, vehicle 10 includes an energy recovery system or is otherwise configured to return torque to the driveline (as negative torque). Energy recovery and / or braking torque can be used to reduce engine speed either before engaging the oncoming clutch or during engagement (when force is applied to the clutch).

[0059] After the oncoming clutch is engaged and the transmission is in the target transmission state, drive torque may be redistributed so that the transmission of the first drive system 20 again transmits torque to the vehicle 10. In one embodiment, the transmission(s) of one or more other drive systems may be shifted as described above by distributing torque away from another drive system and shifting as described in blocks 123-125.

[0060] As noted herein, method 120 is not limited to use with transmissions having two clutches, as the method may be applied to systems having any number of clutches. For example, a transmission with more than two clutches may have multiple off-going clutches and / or multiple on-coming clutches.

[0061] Fig. 4A-4C illustrate aspects of an example in which the transmission 70 is upshifted, or shifted from a low gear state having a lower gear ratio (1:x, where x is less than one) to a high gear state having a higher gear ratio (e.g., 1:1). Fig. 5A-5C show aspects of an example in which the transmission 70 is downshifted or shifted from the high gear state to the low gear state.

[0062] In these examples, speed relationships between the components of the drive unit 20 and the transmission 70 are schematically represented by a speed diagram 170. A lever 172 corresponds to the arrangement of the components in Fig. 2, and mathematically indicates the relationships between the rotational speeds of the components of the transmission system 26. One component is shown vertically along the lever 172 to indicate the spatial locations of the components relative to one another. The engine 22, the first clutch 112 (C1), and the second clutch 114 (C2) are also schematically shown.

[0063] A fulcrum 174 represents the speed of the ring gear 110 and the output speed, a fulcrum 176 represents the engine speed (i.e., the speed of the engine 22) and the carrier speed (speed of the carrier 104), and a fulcrum 178 represents the speed of the sun gear 108 and the speed of the first clutch 112 (i.e., the speed of the clutch disc, referred to as the “first clutch speed”).

[0064] The speeds can be graphically displayed by tilting the lever 172 to show the relative speeds of each component. When the lever 172 is vertical (i.e., extending toward a zero-speed axis Z that is perpendicular to an axis A), the engine speed, the output speed, and the first clutch speed are all zero. When the lever 172 is tilted, at least two components have a non-zero speed, and the speeds of the components are defined by a speed relationship. A non-zero speed of a particular component corresponds to a horizontal distance along axis A from the zero-speed axis Z. The tilt of the lever 172 is represented by a speed line 180. The engine speed is also represented by an engine speed line 182.

[0065] Fig. 4A illustrates the drive unit 20 when the transmission 70 is in the low gear state. The first clutch 112 (C1) is engaged (closed), so the sun gear 108 is stationary, and the second clutch 114 (C2) is disengaged (open). In this state, the engine speed (referred to as "MGU-spd / MGU speed") is higher than the output speed (referred to as "output"), and the first clutch speed is zero. This is illustrated by the speed line 180 forming an acute angle with the zero speed axis Z.

[0066] When an upshift request is received, torque is transmitted to the drive unit 30, and then the first clutch 112 (C1) is opened so that the engine 22 does not provide torque to the vehicle wheels.

[0067] During the shifting process, the speed of the first clutch and the speed of the sun gear 108 begin to increase, as shown in Fig. 4B. The engine speed is reduced so that it is equal to the output speed, which is represented by the intersection of speed lines 180 and 182. At this time, the clutch speed (relative speeds of the flywheel and clutch disc) of the second clutch 114 (C2) is zero. The second clutch 114 (C2) may then be engaged, and the transmission 26 is in the high gear state (engine speed and output speed are equal), as shown in Fig. 4C.

[0068] Fig. Figure 5A illustrates the drive unit 20 when the transmission 26 is in the high gear state. The first clutch 112 (C1) is open, and the second clutch 114 (C2) is engaged, locking the ring gear 110 to the carrier 104. In this state, the engine speed (MGU-spd / MGU-speed) is equal to the output speed (output). The speeds of the sun gear 108 (and clutch disc C1), the ring gear 110, and the carrier 104 are equal to the engine speed, and the second clutch speed (relative speeds of the clutch disc and flywheel) is zero.

[0069] When a downshift request is received, torque is transmitted to the drive unit 30, and then the second clutch 112 (C2) is opened so that the engine 22 does not provide torque to the vehicle wheels.

[0070] During the gear shift, the engine speed increases. Fig. Figure 5B illustrates the engine speed during acceleration of the engine 22, illustrating an intermediate speed that exceeds the output speed. The engine speed is increased until the engine speed corresponds to the speed ratio of the low gear condition, as indicated by the speed line 180 in Fig. 5C.

[0071] Fig. Figure 6 illustrates aspects of one embodiment of a computer system 140 that can perform various aspects of the embodiments described herein. Computer system 140 includes at least one processing device 142, generally including one or more processors for performing aspects of the image acquisition and analysis methods described herein.

[0072] Components of computer system 140 include processing device 142 (such as one or more processors or processing units), memory 144, and a bus 146 that connects various system components, including system memory 144, to processing device 142. System memory 144 may be a non-transitory, computer-readable medium and may include a plurality of computer-readable media. These media may be any available media accessible by processing device 142, including both volatile and non-volatile media, as well as removable and non-removable media.

[0073] System memory 144 includes, for example, non-volatile memory 148, such as a hard disk, and may also include volatile memory 150, such as random access memory (RAM) and / or cache memory. Computer system 140 may also include other removable / non-removable, volatile / non-volatile storage media of the computer system.

[0074] System memory 144 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments described herein. For example, system memory 144 stores various program modules that generally perform the functions and / or methods of the embodiments described herein. A module 152 may be included for performing functions related to receiving requests and controlling transmission components, and a module 154 may be included for performing functions related to controlling engine speed, as described herein. System 140 is not so limited, as other modules may be included.As used herein, the term "module" refers to a processing circuit, which may include an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and memory executing one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0075] Processing device 142 may also communicate with one or more external devices 156, such as a keyboard, a pointing device, and / or other devices (e.g., a network card, a modem, etc.) that enable processing device 142 to communicate with one or more other computing devices. Communication with various devices may occur via input / output (I / O) interfaces 164 and 165.

[0076] Processing device 142 may also communicate with one or more networks 166, such as a local area network (LAN), a general purpose wide area network (WAN), a bus network, and / or a public network (e.g., the Internet), via a network adapter 168. It should be understood that other hardware and / or software components may also be used in connection with computer system 40, even if not shown. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external hard disk arrays, RAID systems, data archiving systems, etc.

[0077] The terms "a" and "an" do not imply a limitation of quantity, but denote the presence of at least one of the recited items. The term "or" means "and / or" unless the context clearly indicates otherwise. References to "an aspect" throughout this specification mean that a particular element (e.g., a feature, structure, step, or property) described in connection with the aspect is included in at least one of the aspects described herein and may or may not be present in other aspects. Additionally, it is understood that the described elements in the various aspects may be combined in any suitable manner.

[0078] When an element such as a layer, film, region, or substrate is described as lying "on" another element, it may lie directly on top of the other element, or there may be intervening elements. In contrast, when an element is described as lying "directly on" another element, there are no intervening elements.

[0079] Unless otherwise stated herein, all examination standards are the most recent standard in effect on the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the examination standard appears.

[0080] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0081] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalent elements may be substituted without departing from its scope. Additionally, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, the present disclosure is not intended to be limited to the particular embodiments disclosed, but is intended to include all embodiments falling within its scope.

Claims

[1] A system for controlling a transmission state of a vehicle (10), comprising: a control unit (52) connected to a first drive system (20) and a first transmission, wherein the first drive system (20) comprises an electric motor (22), the first transmission comprises a gear system, a first clutch (112) and a second clutch (114); a carrier (104) rotatably coupled to the electric motor (22) and comprising a plurality of planetary gears (106), a sun gear (108) and a ring gear (110), wherein the ring gear (110) is rotatably coupled to an output of the transmission, and wherein the first clutch (112) is operable to immobilize the sun gear (108) and the second clutch (114) is operable to rotatably couple the electric motor (22) and the carrier (104) to the ring gear (110); wherein the control device (52) is configured to perform: Receiving a request to change from an initial transmission state to a target transmission state when drive torque is applied to the vehicle (10), wherein one of the first clutch (112) and the second clutch (114) is an off-going clutch engaged with the gear system in the initial transmission state, and another of the first clutch (112) and the second clutch (114) is an on-coming clutch disengaged from the gear system in the initial transmission state; Distributing the drive torque so that all of the drive torque is provided by a second drive system (30) and the first drive system (20) does not provide any drive torque to the vehicle (10); Completely disengage the outgoing clutch from the gear system; Controlling an engine speed based on a speed relationship of the target transmission state to reduce a slip speed of the oncoming clutch; and fully engaging the oncoming clutch to place the first drive system (20) in the target transmission state. [2] The system of claim 1, wherein the controller (52) is further configured to perform: redistributing the drive torque such that at least a portion of the drive torque is applied by the first drive system (20). [3] The system of claim 1, wherein the controller (52) is further configured to perform: Redistributing the drive torque so that the second drive system (30) does not provide drive torque to the vehicle (10), the second drive system (30) is connected to a second transmission; and Changing a transmission state of the second transmission from the first transmission state to the second transmission state. [4] The system of claim 1, wherein the first transmission has a low gear condition in which the first clutch (112) is the off-going clutch and the second clutch (114) is the on-coming clutch, and a high gear condition in which the first clutch (112) is the on-coming clutch and the second clutch (114) is the off-going clutch. [5] The system of claim 4, wherein the initial transmission state is the low gear state and the target transmission state is the high gear state, and controlling the engine speed comprises reducing the engine speed to match the engine speed with a speed of the ring gear. [6] The system of claim 4, wherein the initial transmission state is the high gear state and the target transmission state is the low gear state, and controlling the engine speed comprises increasing the engine speed based on the speed relationship of the low gear state. [7] A method for controlling a transmission state of a vehicle (10), comprising: Receiving a request at a controller (52) to change from an initial transmission state to a target transmission state when drive torque is applied to the vehicle (10), wherein the controller (52) is connected to a first drive system (20) and a first transmission, the first drive system (20) comprising an electric motor (22), the first transmission comprising a gear system, a first clutch (112), and a second clutch (114), wherein one of the first clutch (112) and the second clutch (112) is an off-going clutch engaged with the gear system in the initial transmission state, and another of the first clutch (112) and the second clutch (114) is an on-coming clutch disengaged from the gear system in the initial transmission state, the gear system comprising a carrier (104) rotatably coupled to the electric motor (22) and a plurality of planetary gears (106),a sun gear (108) and a ring gear (110) rotatably coupled to an output of the transmission, and wherein the first clutch (112) is operable to immobilize the sun gear (108) and the second clutch (114) is operable to rotatably couple the electric motor (22) and the carrier (104) to the ring gear (110); Distributing the drive torque so that all of the drive torque is provided by a second drive system (30) and the first drive system (20) does not provide any drive torque to the vehicle (10); Completely disengage the outgoing clutch from the gear system; Controlling an engine speed based on a speed relationship of the target transmission state to reduce a slip speed of the oncoming clutch; and fully engaging the oncoming clutch to place the first drive system (20) in the target transmission state. [8] The method of claim 7, further comprising: Redistributing the drive torque so that the second drive system does not provide drive torque to the vehicle (10), the second drive system is connected to a second transmission; and Changing a transmission state of the second transmission from the first transmission state to the second transmission state.

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