Gear shift control method for hybrid power system and hybrid power system

Abstract

A shift control method for a hybrid power system, comprising the following steps: a neutral step, wherein after the clutch is disengaged and the torque of the motor is reduced to zero, the transmission is controlled to be in a neutral state; a speed control step, wherein after the transmission is in a neutral state, the clutch is controlled to be engaged, and the torque of the motor is controlled so that the speed of the motor and the speed of the engine are synchronized and close to the target speed; and a gear-engaging step, wherein after the speed of the motor and the speed of the engine are approximately the same as the target speed, the transmission is controlled to complete the gear-engaging to the target gear. The above-mentioned shift control method greatly shortens the shift time, thereby reducing or even eliminating the adverse effects of the long shift time on the acceleration performance, charging efficiency and driving performance of the vehicle. A hybrid power system using the above-mentioned shift control method is also provided.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically to a shift control method for a hybrid power system and a hybrid power system using the shift control method. Background Art

[0002] Figure 1 A topological structure diagram of a hybrid power system for a vehicle is shown. The hybrid power system includes an engine ICE, an electric motor EM, a clutch C and a transmission T.

[0003] The output shaft of the engine ICE is connected to the input / output shaft of the motor EM via the clutch C. When the clutch C is engaged, the output shaft of the engine ICE is transmission-coupled with the input / output shaft of the motor EM; when the clutch C is disengaged, the output shaft of the engine ICE is transmission-coupled with the input / output shaft of the motor EM. The input / output shaft of the motor EM is directly connected to the input shaft of the transmission T in a coaxial manner, so that the input / output shaft of the motor EM is always transmission-coupled with the input shaft of the transmission T. In addition to the input shaft, the transmission T also includes necessary transmission mechanisms (such as an output shaft, a synchronizer, and multiple sets of gears). In this hybrid system, the engine ICE is transmission-coupled with the input shaft of the transmission T in a controlled manner, and the motor EM is always transmission-coupled with the input shaft of the transmission T. In this way, the above hybrid system has a so-called P2 architecture.

[0004] exist Figure 1 In the hybrid system shown, when the transmission shifts gears as required, the existing shift control method can be used to shift gears. Figure 2 1 shows a curve of the parameters of each component in the hybrid power system changing with time during the gear shifting process using the existing gear shifting control method, wherein the abscissa represents time. The above existing gear shifting control method is described below with reference to the accompanying drawings.

[0005] like Figure 2 As shown, the time point when the method is started is defined as point a (hereinafter referred to as a time point), and the time point when the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C are reduced to zero is defined as point b. In the time period from point a to point b ( Figure 2 In the step a→b), the torque of the engine ICE first gradually decreases, then the torque of the motor EM and the torque capacity of the clutch C gradually decrease, and the speed of the engine ICE and the speed of the motor EM gradually increase. At point b, the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C decrease to zero.

[0006] Furthermore, let the time point when the transmission T changes to the neutral state be point c. In the time period from point b to point c ( Figure 2b→c), the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C remain zero. The transmission control unit controls the transmission T so that the engaged synchronizer and the gear in the transmission T are disengaged, so that the transmission T is transformed into a neutral state. During this period, the speed of the engine ICE increases slightly, while the speed of the motor EM has begun to decrease.

[0007] Furthermore, the time point when the speed of the motor EM approaches the target speed and the difference between the speed of the motor EM and the target speed is reduced to a predetermined value is set as point d. In the time period from point c to point d ( Figure 2 c→d), the torque of the engine ICE and the torque capacity of the clutch C remain zero, and the speed of the motor EM is gradually approached to the target speed by controlling the torque of the motor EM ( Figure 2 ). The target speed is calculated based on the speed of the output shaft of the transmission T. At point d, the speed of the motor EM keeps approaching the target speed, and the difference between the speed of the motor EM and the target speed is reduced to a predetermined value, at which point the transmission control unit controls the transmission to start shifting gears. In addition, during the above time period, the speed of the engine ICE gradually increases and is not affected.

[0008] Furthermore, the time point when the speed of the motor EM is equal to the target speed after the transmission T is engaged is set as point e. In the time period from point d to point e ( Figure 2 In the transition from point d to point e), the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C remain zero, and the synchronizer in the transmission T engages with the corresponding gear to achieve gear engagement. In the above stages, the speed of the motor EM gradually approaches the target speed, and finally at point e, the speed of the motor EM is roughly synchronized with the target speed.

[0009] Furthermore, the time point when the speed of the engine ICE approaches the target speed and the difference between the speed of the engine ICE and the target speed is reduced to a predetermined value is defined as point f. In the time period from point e to point f ( Figure 2 e→f), the clutch is in a slipping state, the torque of the motor EM increases to a certain value and then remains unchanged, the torque of the engine ICE remains zero, and the speed of the engine driven by the motor EM gradually approaches the target speed. During the above time period, the speed of the motor EM is synchronized with the target speed and gradually increases.

[0010] Furthermore, let the time point when the speed of the engine ICE is synchronized with the target speed and the clutch is turned into the engaged state be point g. In the time period from point f to point g ( Figure 2f→g), the clutch C is in a slipping state, the torque of the motor EM remains unchanged, and the torque of the engine ICE remains zero. The motor EM drives the engine ICE, so that the speed of the engine ICE gradually approaches the speed of the motor EM and the two are finally synchronized, and the clutch C finally changes from the slipping state to the engaged state. During the above time period, the speed of the motor EM is synchronized with the target speed and gradually increases.

[0011] Furthermore, let the time point when the torque of the engine ICE increases to a predetermined value be point h. Figure 2 In the above time period, the speed of the motor EM and the speed of the engine ICE are synchronized with the target speed and gradually increase.

[0012] In the above-mentioned shift control method, since the speed of the motor EM and the speed of the engine ICE approach the target speed in time sequence, the long shift time may cause multiple problems. First, the acceleration performance of the vehicle may be greatly affected during the shift process; second, the interval between two shifts may be very short in the case of continuous shifting, resulting in frequent shifting, which may have an adverse effect on the driving performance of the vehicle; third, when the hybrid system is in parallel driving mode, it may have an adverse effect on the efficiency of battery charging, resulting in insufficient battery power; finally, if the hybrid system has no other additional power source, a long power interruption phenomenon will occur during the shift process, which will have an adverse effect on the driving performance of the vehicle.

[0013] Application Contents

[0014] This application is made based on the defects of the above-mentioned prior art. One purpose of this application is to provide a shift control method for a hybrid power system, which can significantly shorten the shift time compared with the shift control method described in the background technology. Another purpose of this application is to provide a hybrid power system using the above-mentioned shift control method.

[0015] In order to achieve the above application objectives, this application adopts the following technical solutions.

[0016] The present application provides a shift control method for a hybrid power system as follows, wherein the hybrid power system includes an engine, a motor, a clutch and a transmission, wherein the engine is controllably transmission-connected to an input shaft of the transmission via the clutch, and the motor is always transmission-connected to the input shaft of the transmission, and the shift control method includes the following steps:

[0017] a neutral step, wherein after the clutch is disengaged and the torque of the motor is reduced to zero, the transmission is controlled so that the transmission is in a neutral state;

[0018] a speed control step, wherein after the transmission is in the neutral state, the clutch is controlled to be engaged, and the torque of the motor is controlled so that the speed of the motor and the speed of the engine are synchronized and close to a target speed; and

[0019] A gear shifting step, wherein after the speed of the motor and the speed of the engine are substantially the same as the target speed, the transmission is controlled to complete the gear shifting to the target gear.

[0020] In an optional solution, during the execution of the speed control step, the torque of the motor is controlled so that at any time point the torque of the motor is equal to the sum of the first feedforward torque T1, the second feedforward torque T2 and the feedback torque T3,

[0021] Among them, the first feedforward torque T1 is the torque used to drive the engine at the current time point so that the speed of the engine is close to the speed of the motor, the second feedforward torque T2 is the torque used to make both the speed of the engine and the speed of the motor close to the target speed at the current time point, and the feedback torque T3 is the feedback torque calculated using the PID control method based on the difference between the target speed and the speed of the motor at the current time point.

[0022] In another optional solution, the first feedforward torque T1 satisfies T1=Tc, wherein Tc is equal to the torque capacity of the clutch at the current time point,

[0023] The second feedforward torque T2 satisfies T2=J×W / T, wherein J is the sum of the moment of inertia of the motor and the moment of inertia of the engine, W is the difference between the speed of the motor at the current time point and the target speed, T is the target synchronization time,

[0024] The feedback torque T3 satisfies T3=Kp×Δw(t)+Ki×∫Δw(t)dt+Kd×dΔw(t) / dt, wherein Δw(t) is a function of the difference between the target speed and the speed of the motor changing with time t, ∫Δw(t)dt is the integral value of the function Δw(t) within a predetermined time range, dΔw(t) / dt is the differential of the function Δw(t) with respect to time t, Kp is the proportional coefficient of the PID control, Ki is the integral coefficient of the PID control, and Kd is the differential coefficient of the PID control.

[0025] In another optional solution, after the speed of the engine is substantially synchronized with the speed of the motor, the torque of the motor is controlled so that the first feed-forward torque T1 is reduced to zero.

[0026] In another optional solution, after the speed of the engine and the speed of the motor are synchronized and the difference between the speed of the engine and the target speed is less than a predetermined value, the torque of the motor is controlled so that the second feed-forward torque T2 is reduced to zero.

[0027] In another optional solution, before the transmission completes shifting into the target gear, the feedback torque T3 always exists, so that the speed of the motor and the speed of the engine are always close to the target speed.

[0028] In another optional solution, during the execution of the neutral step, before reducing the torque capacity of the clutch, the engine is first controlled to gradually reduce the torque of the engine, so that the torque capacity of the clutch is always greater than the torque of the engine until the clutch is disengaged.

[0029] In another optional solution, the target speed is calculated based on the speed of the output shaft of the transmission.

[0030] In another optional scheme, after the gear shifting step is completed, the gear shifting control method further includes a torque control step, wherein the motor and the engine are controlled so that the torque of the motor and the torque of the engine are increased.

[0031] The present application also provides a hybrid power system as follows, the hybrid power system includes an engine, a motor, a clutch and a transmission, the engine is controllably transmission-connected to an input shaft of the transmission via the clutch, the motor is always transmission-connected to the input shaft of the transmission, the hybrid power system also includes a control device, the control device includes an engine control unit, a motor control unit, an auxiliary control unit and a transmission control unit,

[0032] The control device sends a control instruction to the corresponding control unit to implement the following steps: after the auxiliary control unit disengages the clutch and the motor control unit controls the torque of the motor to be reduced to zero, the transmission control unit controls the transmission to be in a neutral state; after the transmission is in the neutral state, the auxiliary control unit controls the clutch to engage the clutch, and the motor control unit controls the torque of the motor so that the speed of the motor and the speed of the engine are synchronized and close to the target speed; and after the speed of the motor and the speed of the engine are approximately the same as the target speed, the transmission control unit controls the transmission to complete the shifting of the transmission to the target gear.

[0033] In an optional solution, in the process in which the motor control unit controls the torque of the motor so that the speed of the motor and the speed of the engine are synchronized and close to the target speed, the motor control unit controls the torque of the motor so that at any time point the torque of the motor is equal to the sum of the first feedforward torque T1, the second feedforward torque T2 and the feedback torque T3,

[0034] Among them, the first feedforward torque T1 is the torque used to drive the engine at the current time point so that the speed of the engine is close to the speed of the motor, the second feedforward torque T2 is the torque used to make both the speed of the engine and the speed of the motor close to the target speed at the current time point, and the feedback torque T3 is the feedback torque calculated using the PID control method based on the difference between the target speed and the speed of the motor at the current time point.

[0035] In another optional solution, after the speed of the engine is substantially synchronized with the speed of the motor, the motor control unit controls the torque of the motor so that the first feed-forward torque T1 is reduced to zero.

[0036] In another optional solution, after the speed of the engine and the speed of the motor are synchronized and the difference between the speed of the engine and the target speed is less than a predetermined value, the motor control unit controls the torque of the motor so that the second feedforward torque T2 is reduced to zero.

[0037] In another optional solution, before the transmission completes shifting into the target gear, the motor control unit controls the torque of the motor so that the feedback torque T3 always exists, so that both the speed of the motor and the speed of the engine are always close to the target speed.

[0038] In another optional solution, before the auxiliary control unit reduces the torque capacity of the clutch, the engine control unit first controls the engine to gradually reduce the torque of the engine, so that the torque capacity of the clutch is always greater than the torque of the engine until the clutch is disengaged.

[0039] In another optional solution, after the transmission control unit controls the transmission to shift into the target gear, the motor control unit controls the motor and the engine control unit controls the engine, so that the torque of the motor and the torque of the engine increase.

[0040] In another optional solution, the hybrid power system further includes an additional motor, and the additional motor is arranged downstream of the transmission on the transmission path of the driving torque of the hybrid power system.

[0041] By adopting the above technical solution, the present application provides a shift control method for a hybrid power system and a hybrid power system adopting the above shift control method. The hybrid power system includes an engine, a motor, a clutch and a transmission, the engine is controlled to be transmission-connected with the input shaft of the transmission via the clutch, and the motor is always transmission-connected with the input shaft of the transmission. Further, for the above hybrid power system, the shift control method according to the present application includes a neutral step, a speed control step and a gear-engaging step. In the neutral step, after the clutch is disengaged and the torque of the motor is reduced to zero, the transmission is controlled to be in a neutral state. In the speed control step, after the transmission is in a neutral state, the clutch is engaged and the torque of the motor is controlled so that the speed of the motor and the speed of the engine are synchronized and close to the target speed. In the gear-engaging step, after the difference between the speed of the motor and the speed of the engine and the target speed reaches a predetermined value, the transmission is controlled to achieve gear-engaging to the target gear.

[0042] As described above, in the existing shift control method described in the background technology, the speed of the motor is synchronized with the target speed and the speed of the engine is synchronized with the target speed in different time periods. In contrast, in the shift control method according to the present application, by controlling the torque of the motor, the speed of the motor can be made close to the target speed while the speed of the engine is also made close to the target speed, and finally the speed of the motor and the speed of the engine are synchronized with the target speed at substantially the same time. In this way, the shift time of the hybrid system is greatly shortened, thereby reducing or even eliminating the adverse effects of the long shift time on the acceleration performance, charging efficiency and driving performance of the vehicle in the background technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1Schematic diagram showing the topological structure of a hybrid power system with a P2 architecture.

[0044] Figure 2 It shows Figure 1 A schematic diagram of a curve showing changes in parameters of various components over time during a gear shifting process in a hybrid power system using an existing gear shifting control method, wherein the abscissa in the figure represents time.

[0045] Figure 3 It shows Figure 1 A schematic diagram of a curve showing changes in parameters of various components over time during a gear shifting process of a hybrid power system using a gear shifting control method according to an embodiment of the present application, wherein the abscissa in the figure represents time.

[0046] Figure 4 It shows Figure 1 A schematic diagram of a curve showing changes in some parameters over time during a gear shifting process of a hybrid power system using a gear shifting control method according to an embodiment of the present application is shown, wherein the curve showing changes in some parameters over time during the time limit for executing a speed control step is mainly shown, and the horizontal axis in the figure represents time.

[0047] Figure 5 1 is a schematic diagram showing the structure of a control device of a shift control system that implements a shift control method according to an embodiment of the present invention.

[0048] Description of Reference Numerals

[0049] ICE engine C clutch EM motor T transmission,

[0050] ECU engine control unit PEU motor control unit TCU transmission control unit HCU hybrid control unit ACU auxiliary control unit. DETAILED DESCRIPTION

[0051] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all feasible methods of the present application, nor to limit the scope of the present application.

[0052] In this application, unless otherwise specified, "transmission connection" refers to a connection between two components that can transmit driving force / torque. The two components can be directly connected or indirectly connected via other mechanisms to transmit driving force / torque between the two.

[0053] In this application, unless otherwise specified, all “points” refer to time points.

[0054] In this application, unless otherwise specified, "speed" refers to the rotational speed. For example, the speed of an engine refers to the rotational speed of the engine, and the speed of a motor refers to the rotational speed of the motor.

[0055] In the present application, as specifically indicated in the figures, “gradually” means that a parameter changes continuously and approximately linearly.

[0056] Specifically, in Figure 1 In the hybrid system with the P2 architecture shown, the engine ICE is controllably transmission-coupled to the input shaft of the transmission T via the clutch C, and the motor EM is transmission-coupled to the input shaft of the transmission T at all times.

[0057] exist Figure 1 In the hybrid system shown, when the transmission shifts gears as required, the shift control method according to an embodiment of the present application may be used to shift gears. Figure 3 and Figure 4 The curve of the parameters of each component in the hybrid system changing with time during the process of using the method is shown in FIG. 1 , wherein the horizontal axis represents time. The shift control method of the present application is described below with reference to the accompanying drawings. In general, the shift control method according to an embodiment of the present application includes a neutral step ( Figure 3 a→c), speed control step ( Figure 3 c→d) and gear shifting steps ( Figure 3 d) and torque control steps ( Figure 3 (d→e).

[0058] like Figure 3 As shown, the time point when the shift control method according to an embodiment of the present application is started is set as point a (hereinafter referred to as a time point), and the time point when the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C are reduced to zero is set as point b. In the time period from point a to point b ( Figure 3 In the above time period, the torque of the engine ICE first gradually decreases, and then the torque of the motor EM and the torque capacity of the clutch C gradually decrease. At point b, the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C decrease to zero. During the above time period, the clutch C changes from the engaged state to the slipping state and finally achieves separation, and in this process, the torque of the engine ICE is always smaller than the torque capacity of the clutch C, thereby preventing the excessive torque of the engine ICE from causing the speed of the engine ICE itself to increase undesirably. During the above time period, the speed of the engine ICE and the speed of the motor EM gradually increase.

[0059] Furthermore, let the time point when the transmission T changes to the neutral state be point c. In the time period from point b to point c ( Figure 3b→c), the torque of the engine ICE, the torque of the motor EM and the torque capacity of the clutch C remain zero. The transmission control unit controls the transmission T to disengage the engaged synchronizer and the gear in the transmission T, so that the transmission T achieves a neutral state. In this stage, the speed of the engine ICE and the speed of the motor EM have begun to gradually decrease.

[0060] Furthermore, it is assumed that the speed of the engine ICE and the speed of the motor EM are synchronized and close to the target speed ( Figure 3 The time point when the difference between the speed of the engine ICE and the speed of the motor EM and the target speed is reduced to a predetermined value (e.g., substantially zero) is point d. During the time period from point c to point d ( Figure 3 c→d), the torque of the engine ICE remains zero; the gradual engagement of the clutch C gradually increases the torque capacity, and finally it is in the engaged state and remains in the engaged state; by controlling the torque of the motor EM (special torque control logic), the speed of the engine ICE and the speed of the motor EM are gradually synchronized and the two gradually approach the target speed. The target speed is calculated based on the speed of the output shaft of the transmission T. At point d, the speed of the engine ICE and the speed of the motor EM have been synchronized, and both are basically synchronized with the target speed. At this time, the transmission control unit controls the transmission T to carry out and complete the gear shifting.

[0061] For the special torque control logic mentioned above, refer to Figure 4 Provide explanation. Figure 4 The higher resolution Figure 3 The curve diagram of each parameter changing with time from point b to point d. Figure 4 In the figure, point a' basically corresponds to Figure 3 Point b in the figure corresponds to point e' Figure 3 Point d in .

[0062] like Figure 4 As shown, point b' is assumed to be the time point at which the special torque control logic starts to be executed after the transmission T changes to the neutral state. In the time period from point a' to point b' ( Figure 4 In the example of the step a'→b'), the transmission T is moved to achieve neutral gear. At point b', the transmission T has been changed to neutral gear. After that, the speed of the engine ICE and the speed of the motor EM need to be synchronized and both are roughly synchronized with the target speed. The torque of the motor EM is controlled by a special torque control logic to achieve this speed synchronization. Specifically, in the time period from point b' to point e', at any time point, the torque of the motor EM is made equal to the sum of the first feedforward torque T1, the second feedforward torque T2 and the feedback torque T3 by using the special torque control logic.

[0063] The first feedforward torque T1 is a torque used to drive the engine ICE so that the speed of the engine ICE approaches the speed of the motor EM at the current time point. The first feedforward torque T1 satisfies T1=Tc, where Tc is equal to the torque capacity of the clutch C at the current time point. As the speed of the engine ICE gradually approaches the speed of the motor EM, at the time point when the speed of the engine ICE is roughly synchronized with the speed of the motor EM, that is, point c', the torque of the motor EM is controlled so that the first feedforward torque T1 becomes zero.

[0064] The second feed-forward torque T2 is the torque used to make the speed of the engine ICE and the speed of the motor EM close to the target speed at the current time point. The second feed-forward torque T2 satisfies T2=J×W / T, where J is the sum of the rotational inertia of the motor EM and the rotational inertia of the engine ICE, W is the difference between the speed of the motor EM and the target speed at the current time point, and T is the target synchronization time (T is a time period, an empirical value obtained from experiments, and the size of T may be different when shifting to different gears). After the speed of the engine ICE and the speed of the motor EM are synchronized and the difference between the two and the target speed is less than a predetermined value, that is, point d', the torque of the motor EM is controlled so that the second feed-forward torque T2 becomes zero. In fact, in the time period from point b' to point d' ( Figure 4 b'→d'), since the speed of the motor EM gradually approaches the target speed, the second feedforward torque T2 is gradually decreasing.

[0065] The feedback torque T3 is the feedback torque calculated based on the difference between the target speed and the speed of the motor EM at the current time point using the PID control method (proportional integral differential control method). Feedback torque T3 = Kp × Δw(t) + Ki × ∫Δw(t)dt + Kd × dΔw(t) / dt, where Δw(t) is a function of the difference between the target speed and the speed of the motor EM changing with time t, ∫Δw(t)dt is the integral value of the function Δw(t) within a predetermined time range (generally the time range from the time point when the PID control is started to the current time point), dΔw(t) / dt is the differential of the function Δw(t) relative to time t, Kp is the proportional coefficient of the PID control, Ki is the integral coefficient of the PID control, and Kd is the differential coefficient of the PID control. The above-mentioned proportional coefficient, integral coefficient and differential coefficient can be obtained by experiment in a sample system of a hybrid power system or can also be obtained by simulation experiments. Before the transmission T is shifted to the target gear, there is always feedback torque to keep the speed of the motor EM and the speed of the engine ICE close to the target speed. In this way, the shifting process is smooth without unexpected impact.

[0066] Furthermore, let the time point when the torque of the engine ICE and the torque of the motor EM increase to the predetermined value be point e. During the time period from point d to point e ( Figure 3 d→e), the clutch C is in the engaged state, the torque of the motor EM gradually increases to a predetermined value and then remains unchanged, and the torque of the engine ICE also gradually increases to a predetermined value. In the above stages, the speed of the motor EM and the speed of the engine ICE are synchronized with the target speed and gradually increase.

[0067] In this way, during the above-mentioned shifting process, the speed of the engine ICE and the speed of the motor EM are adjusted simultaneously by controlling the torque of the motor EM, thereby reducing the time required to synchronize the speed of the engine ICE, the speed of the motor EM and the target speed, thereby greatly shortening the shifting time. In summary, by adopting the above-mentioned technical solution, the shifting control method of the hybrid system according to the present application shortens the power interruption time during the shifting, improves the driving performance and weakens the vibration caused by the shifting.

[0068] The shift control method of the hybrid system according to the present invention is described in detail above, and a hybrid control system using the shift control method will be described below.

[0069] The present application also provides a hybrid power system using the above-mentioned shift control method, and the hybrid power system may include: Figure 1 By adopting the above-mentioned shift control method, the hybrid power system according to the present application can achieve the same effect.

[0070] Furthermore, the hybrid power system also includes a control device for implementing the above-mentioned shift control method. Figure 5 As shown, the control device includes an engine control unit ECU, a motor control unit PEU, an auxiliary control unit ACU, a transmission control unit TCU and a hybrid power control unit HCU. The engine control unit ECU, the transmission control unit TCU, the auxiliary control unit ACU and the motor control unit PEU are all in bidirectional data communication with the hybrid power control unit HCU, so that the engine control unit ECU, the transmission control unit TCU, the auxiliary control unit ACU and the motor control unit PEU can send corresponding parameters to the hybrid power control unit HCU, and the hybrid power control unit HCU can send control instructions to the engine control unit ECU, the transmission control unit TCU, the auxiliary control unit ACU and the motor control unit PEU, so as to control the engine control unit ECU, the transmission control unit TCU, the auxiliary control unit ACU and the motor control unit PEU to operate.

[0071] In this embodiment, the transmission control unit TCU can control Figure 1The gear of the transmission T of the hybrid system in the embodiment is engaged and disengaged with the corresponding synchronous meshing mechanism of the transmission T. Thus, in the neutral step and the gear-engaging step of the above-mentioned shift control method, the transmission control unit TCU can control the gear to engage and disengage with the corresponding synchronous meshing mechanism.

[0072] In this embodiment, the motor control unit PEU can control Figure 1 The motor EM of the hybrid system in the gear shift control method performs torque regulation and speed regulation. For example, in the speed control step of the gear shift control method, the motor control unit PEU can control the motor EM to perform torque regulation so that the speed of the motor EM and the speed of the engine ICE are synchronized and close to the target speed; in the torque control step of the gear shift control method, the motor control unit PEU can control the motor EM to perform torque regulation so that the torque of the motor EM is increased.

[0073] In the present embodiment, the assist control unit ACU can control the change in the torque capacity of the clutch C and the engagement / release of the clutch C.

[0074] In this embodiment, the engine control unit ECU can control Figure 1 The engine ICE of the hybrid system in the gear shift control method performs torque regulation and speed regulation. For example, in the neutral step of the above gear shift control method, the engine control unit ECU can control the engine ICE to perform torque regulation so that the torque of the engine ICE is always less than the torque capacity of the clutch C; in the torque control step of the above gear shift control method, the engine control unit ECU can control the engine ICE to perform torque regulation so that the torque of the engine ICE increases.

[0075] Thus, the structure of the hybrid power system according to the present invention can be summarized as follows. The hybrid power system includes: Figure 1The engine ICE, motor EM, clutch C and transmission T are shown. The engine ICE is controlled to be transmission-connected with the input shaft of the transmission T via the clutch C, and the motor EM is always transmission-connected with the input shaft of the transmission T. The hybrid system also includes a control device, which includes an engine control unit ECU, a motor control unit PEU, an auxiliary control unit ACU and a transmission control unit TCU. The control device (such as a hybrid control unit HCU) sends a control instruction to the corresponding control unit to implement the following steps: after the auxiliary control unit ACU disengages the clutch C and the motor control unit PEU controls the torque of the motor EM to be reduced to zero, the transmission control unit TCU controls the transmission T to put the transmission T in a neutral state; after the transmission T is in a neutral state, the auxiliary control unit ACU controls the clutch C to engage the clutch C, and the motor control unit PEU controls the torque of the motor EM to synchronize the speed of the motor EM with the speed of the engine ICE and approach the target speed; and after the speed of the motor EM and the speed of the engine ICE are substantially the same as the target speed, the transmission control unit TCU controls the transmission T to complete the gear shifting to the target gear. In addition, in more specific steps of implementing the above-mentioned shift control method, each control unit performs specific operations as described in the shift control method on the corresponding object under the control of the control device to implement the above-mentioned shift control method.

[0076] The specific implementation methods of the present application have been described in detail in the above content, and supplementary explanations are given below.

[0077] i. In the process of executing the shift control method of the present application, the torque of the motor is controlled by a special torque control logic, so that the speed of the motor and the speed of the engine are close to the target speed at the same time and synchronized with the target speed at the same time. In this way, the shift time can be greatly shortened.

[0078] ii. The hybrid system that can adopt the shift control method according to the present application is not limited to Figure 1The hybrid power system with a P2 architecture shown in the figure may also be other hybrid power systems. For example, the shift control method according to the present application may be applied to hybrid power systems with P2 and P3 architectures, and may also be applied to hybrid power systems with P2 and P4 architectures. In the hybrid power systems with P2 and P3 architectures, in addition to the above-mentioned motor EM, there is also an additional motor that can be always connected to the input shaft of the transmission T via an intermediate gear. In the hybrid power systems with P2 and P4 architectures, in addition to the above-mentioned motor EM, there is also an additional motor such as a hub motor. That is to say, in the transmission path of the driving torque for driving the wheels to rotate in the hybrid power system according to the present application, the additional motor is arranged downstream of the transmission. In this way, the additional motor can provide driving torque during the shifting process, thereby avoiding the phenomenon of power interruption.

[0079] iii. The device for implementing the above-mentioned shift control method is not limited to the control device described in the above-mentioned specific implementation manner. An independent shift control device can be separately provided to complete the shift control method.

Claims

1. A shift control method for a hybrid power system, the hybrid power system comprising an engine, a motor, a clutch and a transmission, the engine being controllably transmission-connected to an input shaft of the transmission via the clutch, the motor being transmission-connected to the input shaft of the transmission at all times, the shift control method comprising the following steps: a neutral step, wherein after the clutch is disengaged and the torque of the motor is reduced to zero, the transmission is controlled so that the transmission is in a neutral state; a speed control step, wherein after the transmission is in the neutral state, the clutch is controlled to be engaged, and the torque of the motor is controlled so that the speed of the motor and the speed of the engine are synchronized and close to a target speed; as well as A gear shifting step, wherein after the speed of the motor and the speed of the engine are substantially the same as the target speed, the transmission is controlled to complete the gear shifting to the target gear.

2. The shift control method of the hybrid power system according to claim 1, characterized in that: During the speed control step, the torque of the motor is controlled so that at any time point the torque of the motor is equal to the sum of the first feedforward torque T1, the second feedforward torque T2 and the feedback torque T3, Among them, the first feedforward torque T1 is the torque used to drive the engine at the current time point so that the speed of the engine is close to the speed of the motor, the second feedforward torque T2 is the torque used to make both the speed of the engine and the speed of the motor close to the target speed at the current time point, and the feedback torque T3 is the feedback torque calculated using the PID control method based on the difference between the target speed and the speed of the motor at the current time point.

3. The shift control method of the hybrid power system according to claim 2, characterized in that: The first feedforward torque T1 satisfies T1=Tc, where Tc is equal to the torque capacity of the clutch at the current time point, The second feedforward torque T2 satisfies T2=J×W / T, wherein J is the sum of the moment of inertia of the motor and the moment of inertia of the engine, W is the difference between the speed of the motor at the current time point and the target speed, T is the target synchronization time, The feedback torque T3 satisfies T3=Kp×Δw(t)+Ki×∫Δw(t)dt+Kd×dΔw(t) / dt, wherein Δw(t) is a function of the difference between the target speed and the speed of the motor changing with time t, ∫Δw(t)dt is the integral value of the function Δw(t) within a predetermined time range, dΔw(t) / dt is the differential of the function Δw(t) with respect to time t, Kp is the proportional coefficient of the PID control, Ki is the integral coefficient of the PID control, and Kd is the differential coefficient of the PID control.

4. The shift control method of the hybrid power system according to claim 2 or 3, characterized in that: After the speed of the engine is substantially synchronized with the speed of the motor, the torque of the motor is controlled so that the first feed-forward torque T1 is reduced to zero.

5. The shift control method of the hybrid power system according to claim 2 or 3, characterized in that: After the speed of the engine and the speed of the motor are synchronized and the difference between the speed of the engine and the target speed is less than a predetermined value, the torque of the motor is controlled so that the second feed-forward torque T2 is reduced to zero.

6. The shift control method of the hybrid power system according to claim 2 or 3, characterized in that: Before the transmission has completed shifting into the target gear, the feedback torque T3 always exists so that the speed of the motor and the speed of the engine are always close to the target speed.

7. The shift control method of a hybrid power system according to any one of claims 1 to 3, characterized in that: During the neutral step, before reducing the torque capacity of the clutch, the engine is controlled to gradually reduce the torque of the engine, so that the torque capacity of the clutch is always greater than the torque of the engine until the clutch is released.

8. The shift control method of a hybrid power system according to any one of claims 1 to 3, characterized in that: The target speed is calculated based on the speed of the output shaft of the transmission.

9. The shift control method of a hybrid power system according to any one of claims 1 to 3, characterized in that: After the gear engaging step is completed, the gear shift control method further includes a torque control step, in which the motor and the engine are controlled so that the torque of the motor and the torque of the engine are increased.

10. A hybrid power system, comprising an engine, a motor, a clutch and a transmission, wherein the engine is controllably transmission-coupled to an input shaft of the transmission via the clutch, the motor is always transmission-coupled to the input shaft of the transmission, the hybrid power system further comprises a control device, the control device comprises an engine control unit (ECU), a motor control unit (PEU), an auxiliary control unit (ACU) and a transmission control unit (TCU), The control device sends a control instruction to the corresponding control unit to implement the following steps: after the auxiliary control unit (ACU) disengages the clutch and the motor control unit (PEU) controls the torque of the motor to be reduced to zero, the transmission control unit (TCU) controls the transmission to put the transmission in a neutral state; after the transmission is in the neutral state, the auxiliary control unit (ACU) controls the clutch to engage the clutch, and the motor control unit (PEU) controls the torque of the motor so that the speed of the motor and the speed of the engine are synchronized and close to the target speed; and after the speed of the motor and the speed of the engine are approximately the same as the target speed, the transmission control unit (TCU) controls the transmission to complete the shifting of the transmission to the target gear.

11. The hybrid power system according to claim 10, characterized in that: In the process in which the motor control unit (PEU) controls the torque of the motor so that the speed of the motor and the speed of the engine are synchronized and close to the target speed, the motor control unit (PEU) controls the torque of the motor so that the torque of the motor is equal to the sum of the first feedforward torque T1, the second feedforward torque T2 and the feedback torque T3 at any time point, Among them, the first feedforward torque T1 is the torque used to drive the engine at the current time point so that the speed of the engine is close to the speed of the motor, the second feedforward torque T2 is the torque used to make both the speed of the engine and the speed of the motor close to the target speed at the current time point, and the feedback torque T3 is the feedback torque calculated using the PID control method based on the difference between the target speed and the speed of the motor at the current time point.

12. The hybrid power system according to claim 11, characterized in that: After the speed of the engine is substantially synchronized with the speed of the motor, the motor control unit (PEU) controls the torque of the motor so that the first feed-forward torque T1 is reduced to zero.

13. The hybrid power system according to claim 11, characterized in that: After the speeds of the engine and the motor are synchronized and the difference between the speeds of the engine and the motor and the target speed is less than a predetermined value, the motor control unit (PEU) controls the torque of the motor so that the second feed-forward torque T2 is reduced to zero.

14. The hybrid power system according to claim 11, characterized in that: Before the transmission completes shifting to the target gear, the motor control unit (PEU) controls the torque of the motor so that the feedback torque T3 always exists, so that both the speed of the motor and the speed of the engine are always close to the target speed.

15. The hybrid power system according to any one of claims 10 to 14, characterized in that: Before the auxiliary control unit (ACU) reduces the torque capacity of the clutch, the engine control unit (ECU) first controls the engine to gradually reduce the torque of the engine, so that the torque capacity of the clutch is always greater than the torque of the engine until the clutch is disengaged.

16. The hybrid power system according to any one of claims 10 to 14, characterized in that: After the transmission control unit (TCU) controls the transmission to shift into the target gear, the motor control unit (PEU) controls the motor and the engine control unit (ECU) controls the engine, so that the torque of the motor and the torque of the engine increase.

17. The hybrid power system according to any one of claims 10 to 14, characterized in that: The hybrid system further includes an additional electric machine, which is disposed downstream of the transmission on a transmission path of the driving torque of the hybrid system.

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