Engine / motor torque control for torque hole filling in hybrid vehicles

Abstract

The present disclosure provides "Engine / Motor Torque Control for Torque Hole Filling in Hybrid Vehicles". A vehicle includes: a motor between an engine and a transmission; and a controller configured to control the motor and engine torque during an upshift to generate a reserve torque in a preparation phase that is applied to the transmission in a torque phase. When the available motor torque is insufficient to provide the reserve torque, the controller increases the engine torque for the reserve torque and reduces the motor torque so that the combined engine and motor torque meets the driver's demand torque without retarding the spark. A method for controlling a vehicle having a motor connected between an engine and a transmission is also disclosed.

Description

Technical Field

[0001] The present disclosure relates to controlling engine torque and electric motor torque of a hybrid vehicle to provide torque hole filling during a gear shift of an automatic transmission. Background Art

[0002] A stepped or multi-ratio automatic transmission in a vehicle powertrain utilizes various friction elements to automatically shift gears. The friction elements establish a power flow path from a torque source (such as an internal combustion engine and / or traction motor) to the vehicle's traction wheels. As the transmission shifts up through the various available gear ratios, the overall transmission ratio (i.e., the ratio of the transmission input shaft speed to the transmission output shaft speed) decreases.

[0003] In the case of a synchronous upshift, the offgoing clutch (OGC) is released while the oncoming clutch (OCC) is engaged to reduce the transmission gear ratio and change the torque flow path through the transmission. A typical upshift event is divided into a preparatory phase, a torque phase, and an inertia phase. In the preparatory phase, the OCC completes its stroke to prepare for its engagement while reducing the OGC torque holding capacity as a step before its release. During the torque phase (which may also be referred to as the torque transfer phase), the OGC torque is reduced to zero or a very small level to prepare for disengagement. At the same time, according to a conventional upshift control strategy, the OCC torque is increased from a very small level to initiate the engagement of the OCC. The timing of OCC engagement and OGC disengagement results in instantaneous activation of two torque flow paths through the transmission, which may cause torque delivery to drop momentarily at the transmission output shaft. This situation may be referred to as a "torque hole," which may occur before the OGC disengages. Vehicle occupants may perceive the "torque hole" as an undesirable shift shock. When the OCC produces sufficient torque, the OGC is released, marking the end of the torque phase and the beginning of the inertia phase. During the inertia phase, the OCC torque is adjusted to reduce its slip speed to zero. When the OCC slip speed reaches zero, the shift event is complete.

[0004] Torque hole filling is a control strategy that attempts to reduce and / or eliminate the transmission output torque hole during an upshift event. The control strategy for reducing torque disturbances includes providing an increase in the transmission input torque during the torque phase of the upshift. The increase in the transmission input torque must be synchronized with the OCC and OGC to provide a consistent shift feel. Various techniques and / or strategies can be used to increase the transmission input torque from the engine or electric motor. When torque is available, the electric motor torque can be increased almost instantly, but the engine torque is generally slower to respond due to the system dynamics of fuel and air flow. By opening the throttle and providing additional fuel, the engine torque increase can be initiated in anticipation of a transmission upshift. The throttle can be opened beyond the required degree to achieve the driver demand torque, while using spark retard to maintain the desired torque, so that the subsequent spark timing advance can be used to provide a faster torque increase during torque hole filling. This strategy creates a torque reserve so that the engine can quickly provide more transmission input torque. However, there are various limitations to using this approach, for example, external conditions (e.g., high altitude) may prevent the engine from generating the desired torque reserve, which reduces the overall effectiveness of the torque hole filling strategy. Similarly, increasing fueling to provide a torque reserve to an engine having spark retard may adversely affect fuel economy and raw gas emissions. Summary of the invention

[0005] In one or more embodiments, a vehicle includes: an engine; an electric motor selectively coupled to the engine through a first clutch; an automatic step-ratio transmission selectively coupled to the electric motor through a second clutch; and a controller configured to control the engine and the electric motor during an upshift of the automatic transmission to generate a reserve torque applied to the transmission during a torque phase of the upshift in a preparatory phase of the upshift. If the available electric motor torque is sufficient to meet the reserve torque, the controller increases the electric motor torque to provide the reserve torque. If the available electric motor torque is insufficient to meet the reserve torque, the controller increases the engine torque and reduces the electric motor torque to reduce the combined engine and electric motor torque to the driver demand torque, and only when the combined engine and electric motor torque exceeds the driver demand torque after reducing the electric motor torque to a minimum torque threshold, the spark is retarded in the preparatory phase to reduce the engine torque. The controller can control the engine and / or motor torque using an open-loop control strategy, so that no additional torque sensor is required for closed-loop control. Alternatively, a closed-loop or hybrid strategy can be adopted using an observer based on operating parameters other than engine or motor torque.

[0006] In one or more embodiments, a vehicle includes: a motor disposed between an engine and a transmission; and a controller configured to control the motor and engine torque during an upshift to generate a reserve torque applied to the transmission during a torque phase of the upshift in a preparation phase, the controller increasing the engine torque for the reserve torque when the available motor torque is insufficient, and reducing the motor torque so that the combined engine and motor torque meets the driver's required torque.

[0007] According to one or more embodiments, a method for controlling a vehicle having a motor disposed between an engine and an automatic transmission includes, in response to available motor torque being insufficient to satisfy the reserve torque, increasing engine torque for the reserve torque to be applied during a torque phase of an upshift, and reducing the engine torque by retarding spark only when the combined engine torque and motor torque exceed a driver demand torque after reducing the motor torque to a minimum threshold.

[0008] Various advantages may be provided according to embodiments of the present disclosure. For example, various embodiments coordinate engine and motor torque to provide torque hole filling during upshifts, thereby reducing torque disturbances transmitted from the powertrain to the vehicle body, which reduces or eliminates unexpected shift shock. In addition, providing motor torque priority for torque hole filling may improve overall powertrain efficiency. Similarly, spark is retarded in the preparation phase to reduce engine torque only when the combined engine and motor torque exceeds the driver demand torque after the motor torque is reduced to a minimum, which may also improve powertrain efficiency and reduce raw gas emissions. One or more embodiments may control engine and / or motor torque without the use of a torque sensor, thereby reducing the number of parts and associated costs.

[0009] The above advantages and other advantages and features will be apparent from the following detailed description when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A is a schematic diagram of a hybrid vehicle having an automatic transmission according to one or more embodiments, wherein the automatic transmission does not include a torque converter;

[0011] Figure 1B is a schematic diagram of a hybrid vehicle having an automatic transmission according to one or more embodiments, wherein the automatic transmission includes a torque converter and a bypass clutch;

[0012] Figure 2 shows control of the engine and motor torque using only the motor torque as reserve torque to provide torque hole filling during an upshift;

[0013] Figure 3shows control of the engine and motor torques using both motor torque and engine torque as reserve torque to provide torque hole filling during an upshift, wherein the motor torque is reduced to reduce the combined torque to the driver demand torque;

[0014] Figure 4 Control of the engine and motor torques using both motor torque and engine torque as reserve torque to provide torque hole filling during an upshift is shown, wherein the motor torque is reduced and spark is retarded to reduce the combined torque to the driver demand torque;

[0015] Figure 5 is a block diagram showing a control system and / or algorithm for controlling motor torque and engine torque during an upshift to generate a reserve torque to be applied to the transmission during a torque phase in a preparatory phase; and

[0016] Figure 6 is a flow chart illustrating operation of a control system or method in a hybrid vehicle for controlling motor torque and engine torque during an upshift to produce a reserve torque applied to the transmission during a torque phase. DETAILED DESCRIPTION

[0017] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show the details of specific components. Therefore, the specific structural details and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to adopt these embodiments in different ways. As will be understood by those of ordinary skill in the art, the various features shown and described with reference to any one of the figures may be combined with the features shown in one or more other figures to produce embodiments that are not explicitly shown or described. The combination of the features shown provides representative embodiments of typical applications. However, for specific applications or implementations, it may be necessary to make various combinations and modifications to these features according to the teachings of the present disclosure.

[0018] like Figure 1A and Figure 1BAs shown in the representative diagram of , a hybrid vehicle may include an electric machine or traction motor disposed between the automatic transmission and the engine. This arrangement is sometimes referred to as a modular hybrid transmission (MHT) arrangement. The engine may be selectively coupled to the traction motor and the automatic transmission via a first clutch or disconnect clutch. The disconnect clutch may allow the vehicle to operate in a pure electric mode (with the engine disconnected) with the traction motor as the primary power source, in a hybrid mode in which the vehicle is driven by both the traction motor and the engine, and / or in a pure engine mode in which the vehicle is driven only by the engine. A second clutch or launch clutch may be provided to selectively couple the traction motor to the automatic transmission.

[0019] refer to Figure 1A and Figure 1B , a schematic diagram of a vehicle 10 is shown. The engine 12 may be operably connected to a starter motor 14, which may be used to crank and start the engine 12 under certain operating conditions. An electric motor or traction motor 16 may be operably connected to a driveline 18 and positioned between the engine 12 and an automatic step-ratio gearbox or transmission 22. The engine 12 may be selectively coupled to the motor 16 and the transmission 22 via a disconnect clutch 20. The torque generated by the engine 12 and the motor 16 may be provided to the transmission 22 via the driveline 18, and the transmission 22 provides torque to drive wheels 24.

[0020] like Figure 1A As shown, the launch clutch 26A can be disposed between the transmission 22 and the engine 12 and / or the motor 16 to selectively couple the torque to the wheels 24 through the transmission 22. Figure 1B As shown, a torque converter 26B with a bypass clutch may be provided between the transmission 22 and the engine 12 and / or the motor 16 to provide torque to the wheels 24 through the transmission 22. Although the removal of the torque converter is Figure 1A The advantages of the embodiments of the present invention, but the present disclosure is also beneficial to reduce the Figure 1B Vibrations in the system of the torque converter 26B in the embodiment shown.

[0021] The vehicle may include a controller 27, such as a vehicle system controller (VSC), for controlling various vehicle systems and subsystems. The controller 27 may include various types of computer-readable storage media to implement volatile and / or permanent memory. The controller 27 communicates with one or more sensors 30 and actuators (not shown). The one or more sensors 30 may be implemented by a torque sensor positioned to measure the input torque of the transmission 22. For example, the torque sensor 30 may be implemented, for example, by a strain gauge-based system, a piezoelectric dynamometer, or a magnetoelastic torque sensor.

[0022] In one embodiment, the controller 27 is a VSC including an engine control unit (ECU) 28 and a transmission control unit (TCU) 29. The ECU 28 is electrically connected to the engine 12 for controlling the operation of the engine 12. The TCU 29 is electrically connected to and controls the motor 16 and the transmission 22. According to one or more embodiments, the ECU 28 communicates with the TCU 29 and other controllers (not shown) via a vehicle network using a common bus protocol (e.g., CAN). Although the illustrated embodiment depicts that the VSC 27 functionality for controlling the powertrain is contained within two controllers (ECU 28 and TCU 29), other embodiments of the hybrid vehicle may include a single VSC controller and / or any other combination of controllers for controlling the powertrain.

[0023] Shifting of an automatic transmission is accompanied by applying and / or releasing multiple friction elements (such as disc clutches, band brakes, etc.) that change the speed and torque relationship by changing the gear configuration. The friction elements can be actuated electrically, hydraulically, mechanically, or by other strategies using one or more associated actuators that can communicate with a microprocessor-based controller that implements a specific control strategy based on signals received from one or more sensors. The combination of achievable gear configurations determines the total number of ratio levels. Although there are various planetary gear and countershaft gear configurations in modern automatic transmissions, the basic principles of shift kinematics are similar.

[0024] During a typical synchronous upshift event from a lower gear configuration to a higher gear configuration, the gear ratio (defined as automatic transmission input shaft speed / output shaft speed) and the torque ratio (defined as automatic transmission output shaft torque / input shaft torque) are both lowered. During the upshift event, the friction element associated with the lower gear configuration (referred to as the offgoing clutch (OGC)) is disengaged, and a different friction element associated with the higher gear configuration (referred to as the oncoming clutch (OCC)) is engaged.

[0025] As described in more detail below, in one embodiment, the controller 27 controls the engine 12 and the motor 16 during an upshift of the transmission 22 to provide torque hole filling by: in response to the available motor torque from the motor 16 being insufficient to meet the reserve torque, increasing the engine torque from the engine 12 for the reserve torque to be applied during the torque phase of the upshift; and reducing the engine torque by retarding the spark only when the combined engine torque and motor torque exceed the driver demand torque after reducing the motor torque to a minimum threshold.

[0026] In various embodiments, the controller 27 is configured to control the engine 12 and the motor 16 during an upshift of the automatic transmission 22 to generate a reserve torque in a preparatory phase of the upshift that is applied to the automatic transmission 22 during a torque phase of the upshift, such as Figures 2 to 4 As shown. The controller 27 is configured to increase the motor torque from the motor 16 to provide the reserve torque if the available motor torque is sufficient to meet the reserve torque. If the available motor torque from the motor 16 is insufficient to meet the reserve torque, the controller 27 increases the engine torque from the engine 12 and reduces the motor torque from the motor 16, thereby reducing the combined engine and motor torque to the driver demand torque. Only when the combined engine and motor torque exceeds the driver demand torque after reducing the motor torque to the minimum torque threshold, the controller 27 can also retard the spark in the preparatory stage to reduce the engine torque from the engine 12.

[0027] Figures 2 to 4 Various vehicle operating parameters are shown during a representative upshift of the automatic transmission 22 according to a representative embodiment, wherein the controller 27 controls engine and motor torque to provide reserve torque in a preparatory phase for use in a torque phase, thereby providing torque hole filling. Figure 2 Control of the engine and motor torques is shown using only the motor torque as a reserve torque to provide torque hole filling during an upshift. Figure 3 Control of the engine and motor torques is shown using both motor torque and engine torque as reserve torque to provide torque hole filling during an upshift, wherein the motor torque is reduced to reduce the combined torque to the driver demand torque. Figure 4 Control of the engine and motor torques is shown using both motor torque and engine torque as reserve torque to provide torque hole filling during an upshift, wherein the motor torque is reduced and spark is retarded to reduce the combined torque to the driver demand torque.

[0028] like Figures 2 to 4 As shown, during the preparation phase, the shift clutch pressure is reduced for the off-going clutch (OGC) 202 while the clutch pressure for the on-coming clutch (OCC) 204 is increased, and this process continues throughout the torque phase and until the OCC 204 transmits all torque and the OGC has been reduced to zero torque during the inertia phase. The torque converter pump wheel speed 206 continues to increase during the preparation phase and the torque phase and decreases during the inertia phase until the shift is completed. Line 210 represents the expected maximum torque hole filling torque applied during the preparation phase and the torque phase. Lines 212 and 240 represent corresponding maximum and minimum motor torque limits or thresholds, which can be based on, for example, Figure 2 , Figure 3 and Figure 4 The representative operating conditions vary depending on the current operating conditions shown.

[0029] Continue to refer Figures 2 to 4 , line 214 represents the torque hole filling torque, wherein the torque modulation is represented by reference numeral 220. Line 216 represents the engine base torque request. Line 218 represents the engine instantaneous torque request. Line 230 represents the driver demand torque (at the impeller or transmission input). Line 232 represents the motor torque request, which is affected by the motor maximum torque limit or threshold 212 and the minimum torque limit or threshold 240.

[0030] like Figure 2 As shown, the available motor torque is sufficient to meet the reserve torque or the requested torque hole filling torque. Therefore, since the motor is able to meet the additional torque request, only the motor is used to fill the torque hole filling request. In the preparation phase of the upshift, the engine torque does not change. Since the motor torque can be increased almost instantaneously, the reserve torque in the preparation phase is simply the controller determining that the motor has sufficient available torque to provide torque hole filling during the torque phase. The motor torque is then commanded to increase during the torque phase to provide torque hole filling. The engine base torque and the instantaneous request torque will match the driver demand torque, and spark retard is not used to reduce the engine torque and the associated combined engine and motor torque.

[0031] exist Figure 3 , the controller determines that the available motor torque is insufficient to meet the requested torque hole fill or reserve torque. Thus, a combination of motor and engine torque is used to provide torque hole fill during the torque phase because the available motor torque alone cannot meet the additional torque request. The engine torque is increased during the preparation phase so that the combined engine and motor torques meet the reserve torque that will be delivered during the torque phase. The motor torque is reduced during the preparation phase to offset the increased engine torque, thereby maintaining (i.e., not exceeding) the driver demand torque (pump torque) at the transmission input. Note that no spark retard is applied and the engine instantaneous and base torques are approximately equal.

[0032] exist Figure 4 In , a combination of motor and engine torque is used to satisfy the reserve torque because the available motor torque is insufficient to satisfy the additional torque request. Figure 3The engine torque is increased during the preparation phase to meet the torque reserve that will be applied during the torque phase. The motor torque is reduced during the preparation phase in an attempt to offset the increase in engine torque so that the input torque of the transmission does not exceed the driver's demand. However, reducing the motor torque to a minimum torque limit or threshold (which may be zero) is not sufficient to achieve the desired torque reduction of the combined engine and motor torque. Therefore, the controller retards the spark to further reduce the engine torque so that the combined engine and motor torque does not exceed the driver's demand torque. The spark timing can then be advanced and / or adjusted by the controller during the torque phase to deliver the reserve torque to the transmission input to provide torque hole filling. Using spark retard only after the motor torque is reduced to a minimum limit or threshold can improve overall system efficiency and reduce feed gas emissions to the vehicle's emissions control system.

[0033] exist Figure 3 and Figure 4 In the operating situation shown, the available motor torque can partially satisfy the requested or desired reserve torque for torque hole filling. The engine base torque and the instantaneous requested torque will exceed the driver demand torque by a portion of the reserve torque that exceeds the available motor torque. In order to maintain the desired driver demand torque at the transmission input, a torque reduction from the motor is requested, such as Figure 3 If the motor torque has been reduced to a minimum motor torque limit or threshold (which may be zero) and the combined motor and engine torque still exceeds the driver demand torque, only then is spark retard used in preparation to further reduce the engine torque, as shown in FIG. Figure 4 shown.

[0034] Figure 5 5 is a block diagram showing a control system and / or algorithm 500 for controlling motor torque and engine torque during upshifting, for generating a reserve torque to be applied to the transmission during the torque phase in the preparation phase. The transmission control device 502 communicates with the vehicle control device 504 to provide a desired torque hole filling (THF) torque reserve 510. At 512, the actual motor torque is compared with the current maximum motor torque (which may vary based on operating conditions such as battery state of charge) or subtracted from the current maximum motor torque, and at 512514, the resulting torque is subtracted from the reserve torque to determine the available motor torque. At 516, a lower limit of zero is applied to the available motor torque. Then, at 518, the available motor torque is added to the driver demand torque. Also as shown at 518, the shift energy management torque can be subtracted. The shift energy management torque can be applied to reduce the shift shock under vehicle and environmental operating conditions. Then, after being limited by the maximum and minimum engine torque limits or thresholds at 520, the resulting torque is used to provide the requested base engine torque.

[0035] At 530, the actual engine torque is subtracted from the driver demand torque, the result of which is limited by the maximum and minimum motor torque limits or thresholds at 532, and the result becomes the requested motor torque for the motor 16. At 534, the torque from 532 is subtracted from the difference between the driver demand torque and the actual engine torque, the difference being limited to a minimum value of zero at 536. The available motor torque is added to the engine torque at 540 and limited by the minimum instantaneous engine torque threshold at 542 to determine the requested instantaneous engine torque from the engine 12.

[0036] like Figure 5 As shown in the diagram of , the control strategy controls the engine and motor torque to provide reserve torque in the preparation phase for torque hole filling in the torque phase. The strategy prioritizes torque from the motor to provide reserve torque. The algorithm also ensures that when the engine is used to generate part of the reserve in the preparation phase of the upshift, no spark retard is applied to meet the expected driver demand.

[0037] As described above, the desired reserve torque for torque hole filling is calculated by the transmission controller using any of a number of known strategies. Based on the current motor torque and the maximum motor torque limit for the current operating conditions, the available motor torque reserve is given 512 by the following equation:

[0038]

[0039] The controller then determines the engine portion of the reserve torque at 514, 516 according to the following equation:

[0040]

[0041] If the available motor torque could satisfy the entire desired reserve torque, the engine portion of the reserve torque would be zero.

[0042] The desired engine base torque is calculated at 518 based on the driver requested torque and the additional desired reserve torque according to the following equation:

[0043]

[0044] in is the desired base engine torque, and is the driver requested torque at the transmission input (the impeller torque for a transmission with a torque converter). The desired driver demand in equation (3) includes any torque modifications from the transmission controller 510. The desired engine base torque is further clipped or limited by the engine maximum and minimum base torque limits or thresholds at 520 to provide the requested engine base torque from the engine 12 In equation (3), it is assumed that the shift energy management torque τ 能量管理 is zero. Under some operating conditions, shift energy management torque may be desired and may be incorporated at 518 according to the following equation:

[0045]

[0046] The desired motor torque is calculated at 530 from the actual engine torque and the desired driver demand according to the following equation:

[0047]

[0048] in is the desired motor torque, and is the actual engine torque. The desired motor torque is further clipped or limited by the maximum and minimum motor torque limits at 532 to calculate the requested motor torque These constraints may include motor considerations (such as maximum current, temperature, speed, etc.) and battery considerations (such as current state of charge, minimum state of charge, battery current limit, etc.).

[0049] The additional torque reduction required by the engine is calculated based on the desired motor torque and the requested motor torque, as shown at 534. This additional torque reduction is clipped to zero at 536, as it is only used to meet the further torque reduction required by the engine according to the following equation:

[0050]

[0051] The desired instantaneous engine torque is calculated at 540 based on the requested base engine torque and the additional torque reduction calculated above according to the following equation:

[0052]

[0053] By limiting the desired torque by the maximum and minimum instantaneous engine torque limits, the controller calculates the requested instantaneous engine torque at 542

[0054] Figure 6is a flow chart illustrating the operation or method of a control system in a hybrid vehicle for controlling motor torque and engine torque during an upshift to produce a reserve torque applied to the transmission during a torque phase. Step 600 determines whether an upshift has been requested. If an upshift has been requested, step 602 determines the desired reserve torque for torque hole filling. The controller determines the available motor torque based on the current motor torque and the motor torque limit or threshold at step 604, wherein the motor torque limit or threshold may change based on current operating conditions (such as motor temperature, battery state of charge, motor current, etc.). If the available motor torque is determined to be sufficient to meet the reserve torque at 606, the controller increases the motor torque to provide the reserve torque during the torque phase of the shift, as shown at 608. If the available motor torque is insufficient to meet the reserve torque as shown at 606, the controller calculates the engine torque required to meet the reserve torque as shown at 610. As shown at 612, the controller increases the engine torque and decreases the motor torque to reduce the combined engine and motor torque to the driver demand torque. As shown at 614, if the combined engine and motor torque exceeds the driver demand torque after reducing the motor torque to the minimum torque threshold, the controller retards the spark in preparation to reduce the engine torque, as shown at 618, and the resulting combined torque is used for the reserve torque at 620. Otherwise, no spark retard is used to reduce the engine torque, and the combined torque is used as shown at 620.

[0055] The process, method or algorithm disclosed herein may be transmitted to or implemented by a processing device, a controller or a computer, which may include any existing programmable electronic control unit or a dedicated electronic control unit. Similarly, the process, method or algorithm may be stored in a variety of forms as data and instructions that can be executed by a controller or a computer, including but not limited to information permanently stored on a non-writable storage medium (such as a ROM device) and information that can be modified and stored on a writable storage medium (such as a floppy disk, a tape, a CD, a RAM device, and other magnetic and optical media). The process, method or algorithm may also be implemented as a software executable object. Alternatively, the process, method or algorithm may be implemented in whole or in part using a suitable hardware component (such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a state machine, a controller or other hardware component or device) or a combination of hardware, software and firmware components.

[0056] Embodiments according to the present disclosure provide torque hole filling to reduce torque disturbances transmitted from the powertrain to the vehicle body during upshifts, thereby reducing or eliminating undesirable shift shock. Limiting the use of engine spark retard can improve overall system efficiency and reduce feed gas emissions to the vehicle emission control system. Coordinating the control of motor and engine torque in a synchronous manner during upshifts, as disclosed and claimed, can also improve shift quality and consistency.

[0057] Although representative embodiments are described above, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive words rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As mentioned above, the features of various embodiments can be combined to form other embodiments that may not be clearly described or illustrated. Although various embodiments may have been described as providing advantages over other embodiments or prior art implementations in terms of one or more desired characteristics or being preferred over other embodiments or prior art implementations, it is recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties, which depend on the specific application and implementation. These properties may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, for any embodiment described as being inferior to other embodiments or prior art implementations in terms of one or more characteristics, these embodiments are not outside the scope of the present disclosure or claims, and can be expected to be used for specific applications.

[0058] According to the present invention, a vehicle is provided, which has: an engine; an electric motor selectively connected to the engine through a first clutch; an automatic transmission selectively connected to the electric motor through a second clutch; and a controller, the controller being configured to control the engine and the electric motor during an upshift of the automatic transmission to generate a reserve torque applied to the automatic transmission during a torque phase of the upshift in a preparation phase of the upshift, wherein if the available electric motor torque is sufficient to meet the reserve torque, the controller increases the electric motor torque to provide the reserve torque; if the available electric motor torque is insufficient to meet the reserve torque, the controller increases the engine torque and reduces the electric motor torque to reduce the combined engine and electric motor torque to the driver's required torque; and only when the combined engine and electric motor torque exceeds the driver's required torque after the electric motor torque is reduced to a minimum torque threshold, the controller retards the spark in the preparation phase to reduce the engine torque.

[0059] According to one embodiment, the invention further features a battery coupled to the electric machine, wherein the minimum torque threshold is based on a state of charge of the battery.

[0060] According to one embodiment, said minimum torque threshold is zero.

[0061] According to one embodiment, the automatic transmission comprises a stepped ratio transmission.

[0062] According to one embodiment, said increasing the engine torque comprises increasing the engine torque to said reserve torque minus a shift energy management torque.

[0063] According to one embodiment, the second clutch comprises a torque converter bypass clutch disposed within a torque converter of the automatic transmission.

[0064] According to one embodiment, the invention also features a starter motor coupled to the engine and configured to crank the engine during starting.

[0065] According to the present invention, a vehicle is provided, which has: a motor arranged between an engine and a transmission; and a controller, wherein the controller is configured to control the motor and the engine torque during an upshift to generate a reserve torque applied to the transmission during a torque phase of the upshift in a preparation stage, the controller increasing the engine torque for the reserve torque when the available motor torque is insufficient, and reducing the motor torque so that the combined engine and motor torque meets the torque required by the driver.

[0066] According to one embodiment, the controller is further configured to reduce engine torque using spark retard during the preparation phase only if the combined engine and motor torque exceeds the driver demand torque after reducing the motor torque to a minimum motor torque.

[0067] According to one embodiment, the controller is further configured to reduce the engine torque during the torque phase to shift energy management torque.

[0068] According to one embodiment, the controller is further configured to increase engine torque for the reserve torque only if the available motor torque is insufficient to satisfy the reserve torque.

[0069] According to one embodiment, the present invention is also characterized by a first clutch disposed between the engine and the motor and a second clutch disposed between the motor and the transmission.

[0070] According to one embodiment, the transmission comprises a torque converter and the second clutch comprises a torque converter bypass clutch.

[0071] According to one embodiment, the invention further features a battery, wherein the available motor torque is based on a state of charge of the battery.

[0072] A method for controlling a vehicle having a motor connected between an engine and a transmission includes, by a controller: in response to available motor torque being insufficient to meet the reserve torque, increasing engine torque for the reserve torque to be applied during a torque phase of an upshift, and reducing engine torque by retarding spark only when the combined engine torque and motor torque exceed a driver demand torque after reducing the motor torque to a minimum threshold.

[0073] According to one embodiment, the minimum threshold is zero.

[0074] According to one embodiment, the invention is further characterized by reducing the engine torque during the torque phase to shift energy management torque.

[0075] According to one embodiment, the available motor torque corresponds to the battery state of charge.

[0076] According to one embodiment, the controller increases the engine torque for the reserve torque based on the available motor torque.

[0077] According to one embodiment, the available motor torque corresponds to the maximum available motor torque minus the currently commanded motor torque.

Claims

1. A vehicle comprising: engine; an electric machine selectively coupled to the engine via a first clutch; an automatic transmission selectively coupled to the electric machine via a second clutch; and a controller configured to control the engine and the motor during an upshift of the automatic transmission to generate a reserve torque applied to the automatic transmission during a torque phase of the upshift in a preparation phase of the upshift, the controller: If the available motor torque is sufficient to satisfy the reserve torque, increasing the motor torque to provide the reserve torque; and If the available motor torque is insufficient to meet the reserve torque: then increasing the engine torque and reducing the motor torque to reduce the combined engine and motor torque to the driver demand torque; and Spark is retarded to reduce engine torque during the preparatory phase only when the combined engine and electric machine torque exceeds the driver demand torque after the electric machine torque is reduced to a minimum torque threshold. 2 . The vehicle of claim 1 , further comprising a battery coupled to the electric machine, wherein the minimum torque threshold is based on a state of charge of the battery.

3. The vehicle of claim 1, wherein the minimum torque threshold is zero.

4. The vehicle of claim 1 wherein the automatic transmission comprises a stepped ratio transmission. 5 . The vehicle of claim 1 , wherein said increasing engine torque comprises increasing engine torque to said reserve torque minus a shift energy management torque.

6. The vehicle of claim 1, wherein the second clutch comprises a torque converter bypass clutch disposed within a torque converter of the automatic transmission.

7. The vehicle of claim 1 further comprising a starter motor coupled to the engine and configured to crank the engine during starting.

8. A vehicle comprising: A motor disposed between the engine and the transmission; and A controller configured to control the motor and engine torque during an upshift to generate a reserve torque applied to the transmission during a torque phase of the upshift in a preparatory phase, increase the engine torque for the reserve torque when the available motor torque is insufficient, and reduce the motor torque so that the combined engine and motor torque meets the driver's demand torque.

9. The vehicle of claim 8 wherein the controller is further configured to use spark retard to reduce engine torque during the preparation phase only if the combined engine and motor torque exceeds the driver demand torque after reducing the motor torque to a minimum motor torque. 10 . The vehicle of claim 8 , wherein the controller is further configured to reduce the engine torque during the torque phase to shift energy management torque.

11. The vehicle of claim 8, wherein the controller is further configured to increase engine torque for the reserve torque only when the available motor torque is insufficient to satisfy the reserve torque.

12. The vehicle of claim 8, further comprising a first clutch disposed between the engine and the motor and a second clutch disposed between the motor and the transmission.

13. The vehicle of claim 12, wherein the transmission includes a torque converter and the second clutch includes a torque converter bypass clutch.

14. The vehicle of claim 8 further comprising a battery, wherein the available motor torque is based on a state of charge of the battery.

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