DE102013104323A1 - Vehicle e.g. hybrid electric car has control device that is provided to increase rotation speed of input unit of clutch element so that available line pressure is increased for controlling slipping of clutch element - Google Patents

Abstract

The vehicle (10) has a clutch element (20) that is connected with an electromotor. A control device is provided to increase the rotation speed of an input unit of the clutch element based on the response of the slipping of the clutch element so that available line pressure is increased for controlling the slipping of the clutch element.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Provisional Application No. 61 / 637,723, filed May 7, 2012, the disclosure of which is incorporated herein in its entirety.

Technical area

The present disclosure relates to the control of a powertrain in a hybrid electric vehicle.

State of the art

Hybrid electric vehicles (HEV) include an internal combustion engine, an electric traction motor and a traction battery. The machine can be connected to the motor in parallel or in series. A torque converter and / or a starting clutch may couple the engine and the engine to a transmission to transfer torque to the wheels. When the vehicle is under relatively high loads or on a slope, the torque required to drive the vehicle is increased.

SUMMARY

According to one embodiment, a method for controlling a vehicle is provided. A current supplied to an electric motor is changed. The electric motor is coupled with wheels via a locked clutch. The changed current changes a torque output of the electric motor. In response to slippage of the clutch due to the changed torque output, a speed at the input of the clutch is increased to increase a line pressure available to the clutch. In further response to the slip of the clutch, the line pressure is applied to control the slip of the clutch.

According to another embodiment, the vehicle has an electric motor. A clutch is configured to be coupled to the electric motor. At least one control device is provided to respond to slippage of the clutch. In response to the slippage, the controller is configured to increase a speed of an input of the clutch beyond a threshold speed such that an available line pressure for controlling the slippage of the clutch is increased.

In yet another embodiment, a method of controlling a vehicle drive system is provided. A current to an electric motor is changed, wherein the electric motor is coupled via a locked clutch with wheels. Changing the current changes a torque output of the electric motor. In response to a slip of the clutch due to the changed torque output, the engine is started to increase a line pressure available to the clutch, and the line pressure is applied to control the slip of the clutch.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 4 is a schematic illustration of a powertrain of a hybrid electric vehicle; FIG.

2 FIG. 3 is a schematic illustration of a power train and other powertrain components; FIG.

3 is a graphical representation of different torques and speeds during a locked vehicle launch, in which a starting clutch does not slip,

4 is a graphical representation of different torques and speeds during an attempted locked vehicle launch, in which a launch clutch slips,

5 is a graphical representation of different torques and speeds while allowing the launch clutch to slip and

6 FIG. 10 is a flowchart of an algorithm implemented by a control system in the vehicle.

DETAILED DESCRIPTION

Embodiments of the present invention are described below. It is to be understood, however, that the disclosed embodiments are mere examples, and that other embodiments may take various and alternative forms. The figures are not necessarily to scale, certain features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed herein should therefore not be construed as limiting, but only as a representative basis for teaching one skilled in the art the various uses of the present invention. As one of ordinary skill in the art can appreciate, various features are described with reference to any of these figures are illustrated and described, combined with features illustrated in one or more other figures to provide embodiments that are not expressly illustrated or described. The combinations of illustrated features provide representative embodiments for typical applications. However, various combinations and changes in features consistent with the teachings of this disclosure may be desirable for particular applications or implementations.

With reference to 1 is a schematic diagram of a vehicle 10 illustrated in accordance with an embodiment of the present invention. The vehicle 10 is a HEV. The powertrain or propulsion system of the vehicle 10 has a machine 12 , an electric motor or motor / generator (M / G) 14 and a power transmission 16 on that between the M / G 14 and the wheels 18 is arranged. A torque converter 19 can be optional between the M / G 14 and the power transmission 16 be provided. The torque converter 19 transfers torque from the M / G 14 to the power transmission 16 , The torque converter 19 may include a lock-up clutch that, when controlled, provides power from the M / G 14 transmits to the remaining downstream components of the drive system, while the torque converter 19 is bypassed. A starting clutch 20 may also be provided and may be downstream of the M / G 14 in place of the torque converter 19 be arranged. When the starting clutch 20 is disengaged, the torque and the speed of the M / G 14 not to the power transmission 16 transmitted, and when the starting clutch is at least partially engaged, torque is transmitted to the power transmission 16 transfer. An auxiliary pump 21 is provided to pump fluid and the starting clutch 20 to control. You have to understand that in place of a torque converter 19 One or more clutches may be provided to selectively torque from the M / G 14 to the power transmission 16 transferred to. Other configurations are also possible.

The M / G 14 Can function as a generator by giving torque from the machine 12 receives and AC power to an inverter 22 supplies. The inverter 22 converts the AC voltage to DC voltage to a traction battery or battery 23 charge. The M / G 14 can function as a generator by using regenerative braking to boost the braking energy of the vehicle 10 to convert into electrical energy that is in the battery 23 is stored. Alternatively, the M / G 14 Act as a motor by supplying power or power from the inverter 22 and the battery 23 receives and torque through the torque converter 19 , the power transmission 16 and finally to the wheels 18 provides. The battery 23 can also use the pump 21 supply, or the pump 21 may be from an auxiliary battery (not shown) of the vehicle 10 be supplied. A differential 24 can be provided to torque from the output of the power train 16 to the wheels 18 to distribute.

A first clutch or disengagement clutch 26 is located between the machine 12 and the M / G 14 , The disconnect clutch 26 can be fully open, partially indented or fully engaged (locked). To the engine 12 let's start the M / G 14 the machine 12 when the disengagement clutch 26 at least partially engaged. Once the machine 12 from the M / G 14 is rotated at a certain speed (for example ~ 100-200 rpm), the fuel inlet and the ignition can begin. That makes it possible for the machine 12 to "start" and torque to the M / G 14 to deliver back; the M / G 14 can the battery 23 charging and / or torque from the machine 12 to the torque converter 19 , through the power transmission 16 and finally to the wheels 18 to distribute. In another embodiment, a separate engine starter motor (not shown) may be provided.

The vehicle 10 also has a control system that in the embodiment of the 1 shown as three separate control devices: an engine control module (ECM) 28 , a power transmission control module (TCM) 30 and a vehicle system control device (VSC) 32 , The ECM 28 is directly with the machine 12 connected, and the TCM 30 can with the M / G 14 and the power transmission 16 be connected. The three control devices 28 . 30 . 32 are interconnected via a Controller Area Network (CAN) 34 connected. The VSC 32 controls the ECM 28 to the machine 12 to control, and the TCM 30 to the M / G 14 and the power transmission 16 to control. Although the control system of the vehicle 10 three separate control devices, such a control system may desirably have more or fewer than three control devices. For example, a separate engine control module can communicate directly with the M / G 14 and the other control devices in the CAN 34 get connected. Furthermore, it must be understood that in the present disclosure references to certain functions provided by the VSC 32 be executed by the ECM 28 and / or the TCM 30 can be controlled.

As described above, the M / G 14 used to the machine 12 to start. This is called engine start-up. It can be beneficial to the machine 12 start through to the M / G 14 to turn and for example the battery 23 charge. It can also be beneficial to the machine 12 to start to accept acceleration requests cover. While starting the machine, the disengagement clutch is on 26 at least partially engaged, and torque from the M / G 14 is through the disconnect clutch 26 and to the machine 12 created. Once the machine 12 is started, can increase the torque through the drive train, for example, due to sudden ignition in the machine 12 to be provided. Increasing the speed of the machine after starting can increase the speed of the M / G 14 be converted and in increased available line pressure in the pump 21 to the clutch 20 to control. Increased speed of the M / G 14 can also cause the battery 23 is charged and / or that more torque to the torque converter 19 as described above. Once the battery 23 is sufficiently charged and the vehicle 10 No machine power to drive anymore, the machine can 12 disabled or shut down.

With reference to 2 is the power transmission 16 shown in detail. You have to understand that 2 just a configuration of a power transmission 16 exemplified. In a vehicle 10 that the exemplary configuration of 2 used, a torque converter may not be required in the vehicle due to the multiple clutches and planetary gear sets within the transmission. When a torque converter is not used in a configuration, references to a "lock-up clutch" or "start-up clutch" include any clutch in the transmission that transmits the wheels 18 at least partially from the M / G 14 can isolate. One must therefore understand that a simplified version of the power transmission 16 combined with a torque converter 19 can be used with fewer clutches and planetary gear sets within the power train 16 required are. Several other embodiments are contemplated with different configurations of the clutches and / or planetary gear sets with or without the use of a torque converter as known in the art.

The power transmission 16 of the 2 has an input shaft 40 on, the torque from the machine 12 and from the M / G 14 either separately or in combination receives. The input shaft 40 is operational with a second clutch 42 and a third clutch 44 connected. Part of the second clutch 42 and the third clutch 44 is with a first planetary gear set (PG) 46 connected to a second planetary gear set (PG) 48 connected is. A reverse clutch or fourth clutch 49 and a slow & reverse brake or fifth clutch 50 can also use the PG 48 get connected. The second PG 48 drives a belt or a chain 52 to power to a third planetary gear set (PG) 54 transferred to. Each of the planetary gear sets 46 . 48 . 54 may include a sun gear, a ring gear and a planet carrier to different gear ratios in the power transmission 16 provided. The third PG 52 provides a final gear ratio to torque from the power train 16 to the differential 24 transferred to.

A main pump 56 provides pressure to each of the clutches to engage / disengage each clutch, as from the TCM 30 required. It is understood that one or more of the couplings 42 . 44 . 49 . 50 can be controlled to be engaged (locked), partially engaged or fully engaged, similar to the operation of the starting clutch 20 and the disconnect clutch 26 , If the second clutch 42 and / or the third clutch 44 For example, the power transmission can be disengaged 16 from the M / G 14 be isolated, so no torque over the power transmission 16 and to the wheels 18 is transmitted. It is also stressed that, although the couplings 42 . 44 as part of the power transmission 16 are illustrated, one or more clutches separated between the M / G 14 and the power transmission 16 can be used instead of in the power transmission 16 to be installed.

With reference to the 1 and 2 , a "locked electric start" or "locked start" is an acceleration (or attempted acceleration) of the vehicle 10 defined while the starting clutch 20 Is blocked. During a locked startup, the M / G increases 14 the speed to the speed of a turbine in the torque converter 19 increase accordingly. This increase in the speed of the turbine adds torque to the wheels accordingly 18 to drive the vehicle 10 added. The machine 12 can over the M / G 14 be started while the start clutch 20 locked during a locked startup. Every torque from the machine 12 and / or the M / G 14 becomes the power transmission 16 transferred while the starting clutch 20 Is blocked.

With reference to the 1 and 3 is a locked startup exemplified while the vehicle 10 operated under normal conditions without a relatively large tensile load or a relatively large slope. Clutch torque capacity is defined by the pressure applied to the starting clutch 20 is available while coming from the auxiliary pump 21 and / or the main pump 56 is operated. The required torque capacity is defined as a torque required to drive the torque converter 19 to accelerate and therefore the vehicle 10 from standstill too accelerate. In 3 can the M / G 14 because there are no large external loads, for example the torque required to accelerate the vehicle 10 deploy as desired. Since the clutch torque capacity exceeds the required torque capacity, power is from the engine 12 not required to cover the acceleration requests. While the starting clutch 20 is locked during acceleration, the speed of an input shaft to the clutch 20 to the speed of the output of the clutch 20 proportionately.

With reference to the 1 and 4 is an attempted start of the vehicle 10 illustrates when the vehicle 10 under relatively heavy towing or driving on a relatively steep slope. Due to the large load or the slope remains the starting clutch 20 while the vehicle is stopped, locked. While accelerating the vehicle 10 is controlled, the speed and torque increase in the M / G 14 in a trial, the turbine of the torque converter 19 to turn. The torque capacity of the starting clutch 20 is due to the lower available line pressure from the auxiliary pump 21 reduced. Because the required torque capacity to accelerate the vehicle 10 greater than the clutch torque capacity, the starting clutch begins 20 to slip, in the entrance of the clutch 20 rotates while the output of the clutch 20 generally remains motionless. That from the M / G 14 to the starting clutch 20 transmitted torque is less than the required amount to the power transmission 16 and finally the wheels 18 to turn. The combination of the available pressure from the pumps 21 . 56 and the performance of the M / G 14 can the required torque capacity for driving the vehicle 10 do not cover. Therefore, the vehicle is moving 10 not and the startup clutch 20 slips on. The VSC 32 continues to control the M / G 14 to torque to the starting clutch 20 to provide, but the load and / or the slope, which the vehicle 10 is subject to, is too big, and the M / G 14 Therefore, the power transmission 16 do not supply enough to the wheels 18 to turn.

With reference to the 1 and 5 , a controlled "skip start" is illustrated. The vehicle 10 is again under heavy loads or on a relatively steep slope. A locked startup begins. The M / G 14 and the pressure coming from the auxiliary pump 21 is initially not enough to exceed the required torque capacity and the vehicle 10 drive. Since the required torque capacity exceeds the clutch torque capacity, the starting clutch begins 20 to slide. This causes the input shaft of the clutch 20 to rotate while the output of the clutch 20 generally remains motionless. The VSC 32 detects the slippage of the clutch. Instead of the M / G 14 To continue to try to provide enough torque to propel the vehicle, it allows the VSC 32 the starting clutch 20 to slip (or controls the starting clutch 20 to continue slipping) by reducing the pressure in the starting clutch. In response to the slipping of the starting clutch 20 , controls the VSC 32 the M / G 14 , the machine 12 start, or, if already started, controls the machine 12 to increase their output power. An increase in torque to the clutch 20 (or to the torque converter 19 ) can therefore thanks to the torque increase of the machine 12 to be provided. Once the speed of the input of the clutch 20 was increased beyond a threshold speed, the speed ranges to the available line pressure in the pump 21 to generate to control the slippage of the clutch. Once the threshold speed has been reached and the skid can be controlled, the VSC 32 the coupling 20 control, continue to slip while the machine 12 Provides power. The increase in torque from the machine 12 can the required torque capacity for driving the vehicle 10 cover. This can be referred to as "sliding start" instead of locked start. The VSC 32 For example, slip starting may be controlled based on the torque output from the M / G 14 is insufficient, as from the detected slip of the starting clutch 20 displayed.

Once the machine 12 has increased its torque output, the disengagement clutch 26 be locked so that the machine 12 more torque to the torque converter 19 provides. The clutch torque capacity therefore increases beyond the required torque capacity to the vehicle 10 drive. The turbine speed starts to increase and transmits torque through the power train 16 and to the wheels 18 ,

It is understood that the references to detecting the slippage of the clutch 20 comparing a speed of the input and the output of the clutch 20 may include. Adjacent to the M / G 14 or to the input of the clutch 20 Sensors can be provided to adjust the speed of the input of the clutch 20 capture. Similarly, speed sensors may be near the output of the clutch 20 be provided. Slippage can be detected when the clutch input speed is lower than the clutch output speed. Furthermore, it is necessary to understand that slipping from the VSC 32 can be detected by the pressure in the clutch 20 is detected and by the pressure with the estimated pressure, which locks the clutch 20 required is compared. Numerous other configurations in which the slip in the clutch 20 can be provided can be provided.

In one embodiment, the VSC detects 32 a slip in the starting clutch 20 after an attempted locked electric start. In response to slippage of the coupling 20 , controls the VSC 32 an increase in the speed of the input of the clutch 20 to give a line pressure leading to the clutch 20 is available to increase. The increased speed of the input of the clutch 20 can by increasing a torque output of the machine 12 be realized or by reducing the clutch pressure in the clutch 20 (Allow more slides). The increase in the speed of the input of the clutch 20 increases a speed of the pump 21 so that the available line pressure is increased. As a further reaction to the slippage of the coupling 20 , puts the VSC 32 the increased line pressure also to slip the clutch 20 to control emphatically.

With reference to 1 and 6 For example, there is provided a method of providing sufficient torque to propel a vehicle subject to high loads or steep travel 100 illustrated. During operation 102 For example, a requested acceleration or deceleration is detected by, for example, detecting that a vehicle occupant presses the accelerator pedal or the brake pedal. During operation 104 in response to the required traction, a locked start is attempted, in which the flow leading to the M / G 14 is changed to the torque output of the M / G 14 and therefore the torque delivered to a clutch, such as to the starting clutch 20 , During operation 106 will slip in the starting clutch 20 recorded using the procedures explained above. During operation 108 The VSC controls a slip start, in which the starting clutch 20 , The machine 12 is started by the speed of the input of the starting clutch 20 to increase. Shortly thereafter, the torque capacity in the starting clutch exceeds 20 to drive the vehicle 10 required torque capacity. During operation 110 as soon as sufficient torque to the starting clutch 20 is provided, the VSC 32 the locking of the starting clutch 20 control what increases the torque, that to the power transmission 16 and to the wheels 18 provided.

The processes, methods, or algorithms disclosed herein may be delivered to / implemented by a processing device, controller, or computer that may include any existing programmable electronic control unit or dedicated electronic control unit. Similarly, the processes, methods, or algorithms may be stored as data and instructions executable by a controller or computer in many forms, including, but not limited to, data permanently stored on non-writable storage media, such as ROM devices and data stored variably on recordable media such as floppy disks, magnetic tapes, CDs, RAM devices and other magnetic and optical media. The processes, methods or algorithms may also be implemented in software executable object code. Alternatively, the processes, methods, or algorithms may be implemented in part or in total using appropriate hardware components, such as Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), state machines, control devices or other hardware components or devices, or a combination of Hardware, software and firmware components.

Although exemplary embodiments have been described above, it is not intended that these embodiments describe all possible forms including the claims. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. As described above, the features of various embodiments may be combined to form further embodiments of the invention that are not explicitly described or illustrated. Although various embodiments have been described as providing advantages or preferred over other embodiments or prior art implementations with respect to one or more desired features, one of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes depend on the specific application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life-cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, and so forth. Thus, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more features are not outside the scope of the disclosure and may be desirable for particular applications.

Claims (6)

Vehicle comprising: an electric motor, a clutch configured to be coupled to the electric motor, and at least one control device configured to increase a speed of an input of the clutch in excess of a threshold speed in response to the slip of the clutch, such that an available line pressure for controlling the slippage of the clutch is increased. The vehicle of claim 1, further comprising a torque converter including the clutch. The vehicle of claim 1 or claim 2, wherein the at least one controller is further configured to increase a torque input to the clutch to increase the speed of input of the clutch. The vehicle of claim 3, further comprising a machine coupled to the input of the clutch, the at least one controller further configured to start the engine to increase the torque input to the clutch. Vehicle according to one of claims 1 to 4, wherein the at least one control device is further configured to reduce a clutch pressure in response to the slip of the clutch to further control the slippage of the clutch. The vehicle of claim 1, further comprising a pump configured to provide the available line pressure, wherein the speed of input of the clutch beyond the threshold speed results in a speed of the pump sufficient to reach the available one To generate line pressure to control the slip of the clutch.

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