CN112849121A

CN112849121A - Gear shifting control method and vehicle

Info

Publication number: CN112849121A
Application number: CN201911174650.7A
Authority: CN
Inventors: 熊健; 贺静
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2021-05-28
Anticipated expiration: 2039-11-26
Also published as: CN112849121B

Abstract

The invention discloses a gear shifting control method and a vehicle, wherein the method comprises the following steps: the transmission control unit calculates torque reduction target torque according to the first accelerator information and the initial value of the gear shifting torque of the engine, generates an engine torque reduction request, and sends the engine torque reduction request and the torque reduction target torque to the CAN bus; the electronic control unit responds to the torque reduction request of the engine and controls the unloading torque of the engine according to the torque reduction target torque; the vehicle control unit responds to the torque reduction request of the engine, calculates the motor compensation torque, sends the motor compensation torque to the motor controller through the CAN bus, and the motor controller controls the motor to increase the torque according to the motor compensation torque; and the transmission control unit adjusts the separation position of the clutch according to the torque-reducing target torque until the clutch is separated to the maximum separation position, and controls the gear shifting mechanism to be switched to the target gear. The gear shifting control method and the vehicle can improve gear shifting smoothness, reduce gear shifting noise and pause and frustration and improve comfort.

Description

Gear shifting control method and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a gear shifting control method and a vehicle.

Background

To hybrid vehicle's the control of shifting, disclose in some schemes and calculate motor compensation moment of torsion, adopt the electricity to drive the moment of torsion and shift as power compensation during AMT, it is long to appear shifting time among the AMT gear shifting process, shifts and pause and hinder the scheduling problem. However, the motor compensation torque is calculated only according to the difference between the target torque and the actual torque of the engine, and the obtained motor compensation torque may be larger or smaller, so that the actual output torque is larger than the total required torque, or the phenomena that the engine is rapidly raised during gear shifting, the engine generates noise, or the vehicle has obvious deceleration impact and the like are easily caused, and the gear shifting is not smooth enough.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide a gear shift control method, which can effectively reduce the power interruption and impact problem during gear shifting, and improve the smoothness.

A second object of the invention is to propose a vehicle.

In order to achieve the above object, a shift control method according to an embodiment of a first aspect of the invention includes:

the transmission control unit calculates a torque reduction target torque according to first accelerator information and a gear shifting torque initial value of an engine, generates an engine torque reduction request, and sends the engine torque reduction request and the torque reduction target torque to a CAN bus; the electronic control unit responds to the engine torque reduction request and controls the engine unloading torque according to the torque reduction target torque; the vehicle control unit responds to the torque reduction request of the engine, calculates motor compensation torque, sends the motor compensation torque to a motor controller through a CAN bus, and the motor controller controls the motor to lift the torque according to the motor compensation torque; and the transmission control unit adjusts the separation position of the clutch according to the torque-reducing target torque until the clutch is separated to the maximum separation position, and controls the gear shifting mechanism to be switched to the target gear.

According to the gear shifting control method provided by the embodiment of the invention, during gear shifting, the torque reduction target torque is sent to reduce the output torque of the engine, and the torque of the motor is controlled to be increased according to the compensation torque of the motor while the torque reduction of the engine is controlled, namely, the gear shifting power compensation is realized by utilizing the quick response characteristic of the motor, so that the whole vehicle torque which cannot be provided by the engine due to the torque reduction can be compensated, the power interruption or the pause and contusion can be avoided, the separation position of the clutch is matched with the torque reduction target torque of the engine, the separation position of the clutch is adjusted according to the torque reduction target torque of the engine, the engine noise caused by the fact that the engine torque is reduced too slowly due to the excessively fast separation speed of the clutch can be avoided, the engine braking phenomenon caused by the excessively fast torque reduction of the engine due to the excessively slow.

In order to achieve the above object, a vehicle according to an embodiment of a second aspect of the present invention includes an engine, a motor, a transmission, a vehicle controller, and a CAN bus, where the CAN bus is respectively connected to the engine, the motor, the transmission, and the vehicle controller, the engine includes an electronic control unit, the motor includes a motor controller, the transmission includes a transmission control unit, the electronic control unit, the vehicle controller, and the motor controller perform information interaction through the CAN bus, so as to implement the gear shifting control method.

According to the vehicle provided by the embodiment of the invention, the controller executes the gear shifting control method of the embodiment, so that the smoothness during gear shifting can be improved, the gear shifting noise and the pause feeling can be reduced, and the comfort can be improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of a shift control method according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of signal flow for various controllers of a shift process according to one embodiment of the present invention;

FIG. 3 is a graphical illustration of the variation of various parameters during a shift in accordance with an embodiment of the present invention;

FIG. 4 is a flowchart of a shift control method according to one embodiment of the present invention;

FIG. 5 is a block diagram of a vehicle according to one embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

A shift control method according to an embodiment of the invention is described below with reference to fig. 1 to 4.

Fig. 1 is a flowchart of a shift control method according to an embodiment of the invention, which includes at least steps S1-S4, as shown in fig. 1.

And S1, the transmission control unit calculates the torque reduction target torque according to the first accelerator information and the initial value of the gear shifting torque of the engine, generates an engine torque reduction request, and sends the engine torque reduction request and the torque reduction target torque to the CAN bus.

S2, the electronic control unit responds to the engine torque-down request and controls the engine unloading torque according to the torque-down target torque.

S3, the vehicle control unit responds to the torque reduction request of the engine, calculates the motor compensation torque, sends the motor compensation torque to the motor controller through the CAN bus, and the motor controller controls the motor to lift the torque according to the motor compensation torque.

And S4, the transmission control unit adjusts the separation position of the clutch according to the torque reduction target torque until the clutch is separated to the maximum separation position, and controls the gear shifting mechanism to be switched to the target gear.

According to the gear shifting control method provided by the embodiment of the invention, during gear shifting, a torque reduction target torque is sent to reduce the output torque of an engine, and the torque is increased by controlling the torque reduction of the engine according to the compensation torque of the motor, namely, the gear shifting power compensation is realized by utilizing the quick response characteristic of the motor, so that the whole vehicle torque which cannot be provided by the engine due to the torque reduction can be compensated, the power interruption or the pause and contusion can be avoided, the separation position of the clutch is matched with the torque reduction control of the engine, the separation position of the clutch is adjusted according to the output torque of the engine, the engine noise caused by the over-high separation speed of the clutch and the over-low reduction of the torque of the engine can be avoided, the engine braking phenomenon caused by the over-low separation speed of the clutch and the over-high torque reduction of the engine can.

In some embodiments, the transmission control unit calculating the torque down target torque based on the first throttle information and a shift torque initial value of the engine comprises: the transmission control unit calculates a first torque reduction rate and a second torque reduction rate according to the first throttle information and a gear shifting torque initial value of the engine, wherein the first torque reduction rate is smaller than the second torque reduction rate; the transmission control unit determines a torque-down target torque according to the first torque-down rate, and determines the torque-down target torque according to the second torque-down rate until the engine torque falls to the shift torque threshold when the engine torque falls to the first torque threshold. The method comprises the steps of firstly controlling the engine to slowly reduce torque, and when a first torque threshold value is reached, controlling the engine to quickly reduce torque.

Wherein, in some embodiments, the transmission control unit calculating the first torque down rate and the second torque down rate according to the first throttle information and the initial value of the shift torque of the engine comprises: the transmission control unit obtains a first torque reduction time and a second torque reduction time according to the accelerator opening, wherein the first accelerator information comprises the accelerator opening and accelerator opening change information, for example, a first torque reduction time table of a slow torque reduction stage and a second torque reduction time table of a fast torque reduction stage corresponding to each accelerator opening interval are determined according to a bench test, and the corresponding first torque reduction time and the corresponding second torque reduction time are obtained by looking up a table according to the accelerator opening; the transmission control unit calculates a first torque down rate from the initial value of the shift torque and the first down time, e.g. the first torque down rate is equal to the initial value of the shift torque divided by the first down time; the transmission control unit corrects the second torque reduction time according to the accelerator opening change information to obtain second torque reduction correction time; the transmission control unit calculates a second torque down rate based on the shift torque initial value and the second torque down correction time, e.g., the second torque down rate is equal to the shift torque initial value divided by the second torque down correction time.

Further, the transmission control unit corrects the second torque down time according to the accelerator opening degree change information to obtain a second torque down correction time, including: when the accelerator opening is increased, namely when the accelerator change rate is a positive value, the transmission control unit reduces the second torque reduction time by a preset time period to obtain second torque reduction correction time, so that the gear shifting process can be accelerated; alternatively, the transmission control unit sets the second torque down time as the second torque down correction time when the accelerator opening degree is constant or small, that is, when the accelerator change rate is a non-positive value.

Specifically, referring to fig. 2, a TCU (transmission Control Unit) determines whether the vehicle satisfies a shift condition according to a vehicle speed and an accelerator opening degree at which the vehicle is running, and when the shift condition is not satisfied, an engine torque down request flag is reset and an invalid value 0 is transmitted; when the gear shifting is started, an engine torque-down request mark effective value 1 is sent. If the gear shifting condition is met, namely a gear shifting signal is detected, a torque value of the engine at the gear shifting starting time, namely a gear shifting torque initial value, is recorded, the torque value is a torque reduction target torque initially sent by the TCU, the torque reduction target torque sent by the TCU is shown by referring to a third curve S203 of FIG. 3, a first curve S201 is a first accelerator information change curve, and the TCU sends the initial value of the torque reduction target torque of the engine at a time point t 1.

For example, with reference to an initial value of the torque down target torque transmitted by the TCU, a slow torque down phase is performed until the torque down target torque drops from the initial value to 70% of the initial value with 70% of the torque down target torque as a boundary, and a fast torque down phase is performed until the torque down target torque drops from 70% of the initial value to a shift torque threshold value that allows the clutch to be completely disengaged. The shifting torque threshold value for allowing the clutch to be completely separated is a constant value obtained by a test and is slightly higher than the idle torque of the engine.

Further, with 10% of accelerator opening as one section and 10 sections from 0% of accelerator opening to 100% of accelerator opening, determining a first torque reduction time table of a slow torque reduction stage and a second torque reduction time table of a fast torque reduction stage corresponding to each accelerator section according to a bench test. And acquiring and calculating the percentage of the opening degree of the accelerator, and respectively confirming the first torque reduction time of the slow torque reduction stage and the second torque reduction time of the fast torque reduction stage according to a table look-up method. During the slow torque-down phase, the first torque-down rate is equal to the initial shift torque value divided by the first torque-down time. In the rapid torque reduction stage, the second torque reduction time obtained by a table look-up method is used as the basic torque reduction time, and correction is required according to the change information of the opening degree of the accelerator.

The throttle opening degree is increased in the torque reduction process, the throttle change rate is a positive value, and the final rapid torque reduction time, namely the second torque reduction correction time, is reduced on the basis of the torque reduction time, so that the gear shifting process is accelerated. If the throttle opening degree is kept unchanged or has a decreasing trend in the torque reduction process, the throttle change rate is a non-positive value, and the final rapid torque reduction time, namely the second torque reduction correction time, adopts the basic torque reduction time. In the fast torque-down stage, the second torque-down rate is equal to the initial value of the shifting torque divided by the final fast torque-down time, i.e. the second torque-down correction time.

Further, after determining the torque droop rate, the TCU reduces the torque droop target torque sent from the initial shift torque value at the torque droop rate. Referring to the third curve S203 in fig. 3, the torque-down target torque transmitted by the TCU is decreased at the above-mentioned calculated torque-down rate in the time period from the time point t1 to the time point t2, wherein, in the former period of t1-t2, the slope of the curve changes more gradually, i.e., the torque-down rate is smaller, which is in the slow torque-down period, and in the latter period of t1-t2, the slope of the curve increases, i.e., the torque-down rate is increased, which is in the fast torque-down period. When the torque-down target torque is reduced to a shift torque threshold that allows the clutch to be fully disengaged, and is no longer reduced, the TCU remains delivering a torque-down target torque equal to the shift torque threshold, as shown by the third curve S203 in FIG. 3, the curve is nearly flat during the time period t2-t4, i.e., the TCU remains delivering a torque-down target torque equal to the torque threshold.

As shown in fig. 2, after receiving the engine torque down request flag sent by the TCU as the valid value 1 and the torque down target torque, the ECU (Electronic Control Unit) preferentially responds to the torque down request and controls the engine off-load torque with reference to the torque down target torque sent by the TCU. As shown in fig. 3, wherein the fourth curve S204 is an engine torque variation curve, the ECU controls the engine to output a torque close to the torque-down target torque sent by the TCU from a time point t1 to a time point t2, wherein, during a former period of time t1-t2, the slope of the curve changes less, i.e., the engine torque decreases more slowly, while during a slow torque-down period, and during a latter period of time t1-t2, the slope of the curve changes more, i.e., the engine torque decreases more rapidly, while during a fast torque-down period.

Further, as shown in fig. 2, after receiving that the engine torque reduction request flag sent by the TCU is a valid value 1, the VCU (Vehicle Control Unit) starts calculating the motor compensation torque. In the case where the engine output torque is considered to match the clutch torque without considering the vehicle resistance, the motor compensation torque is calculated by: calculating a torque difference value between the required torque of the whole vehicle and the torque reduction target torque; calculating a quotient of the torque difference value and the gear speed ratio of the motor to obtain the torque required by the motor; and calculating the difference value of the torque required by the motor and the current torque of the motor to obtain the motor compensation torque.

The VCU sends the calculated Motor compensation torque to an MCU (Motor control Unit) through a CAN (Controller Area Network) bus, and simultaneously the VCU sends a torque required by the Motor to the MCU, and the MCU adds the current torque of the Motor and the Motor compensation torque to control and output the total torque required by the Motor. As shown in FIG. 3, wherein the fourth curve S204 is the engine torque variation curve and the fifth curve S205 is the motor torque variation curve, for example, referring to the fourth curve S204 and the fifth curve S205 in FIG. 3, during the period from t1 to t2, when the engine torque decreases, the motor torque increases, and the torque reduced by the vehicle when the engine torque decreases is compensated in real time, so as to ensure the smoothness of the gear shifting.

Further, in the embodiment, the TCU controls the clutch to be disengaged in real time according to the torque reduction target torque, so that the clutch is disengaged to match the torque reduction target torque, and the impact or jerk feeling caused by too fast or too slow clutch disengagement is avoided, and the clutch can be specifically controlled to be disengaged in two steps. The method comprises the following steps that firstly, the clutch is separated to a target separation position corresponding to a torque reduction target torque, wherein the target separation position is calculated according to the torque reduction target torque and a clutch torque transmission characteristic table, and the transmission characteristic table is obtained through calibration of a bench test. As shown in FIG. 3, wherein the sixth curve S206 is the clutch position variation curve, during the time period t1-t3, the clutch is matched with the engine torque and is disengaged, and wherein during the time period t1-t2, the slope variation of the curve is small, namely, the clutch follows the torque-reducing target torque and is disengaged. In the second step, when the torque-down target torque reaches a shift torque threshold, such as when the TCU determines that the engine torque has dropped below a shift torque threshold that allows the clutch to be fully disengaged, the clutch is quickly disengaged to a maximum disengaged position. As shown in FIG. 3, the sixth curve S206, during time t2-t3, when the engine torque drops to the shift torque threshold at time t2, controls the clutch to quickly disengage to the maximum position, i.e., time t2-t3 is the clutch quick disengage phase.

The TCU collects the position of the clutch in real time, when the position of the clutch is judged to be at the maximum separation position, the engaging gear executing mechanism is controlled to remove the gear before gear shifting, and engage the target gear of gear shifting, as shown in fig. 3, in the time period from t3 to t4, the TCU controls the gear shifting executing mechanism to execute the actions of gear disengaging and engaging, and the gear shifting is switched to the target gear, parameters represented by all curves are in a stable stage, the vehicle runs stably in the gear shifting stage, and the smoothness of gear shifting is improved.

Further, in an embodiment, the shift control method of the embodiment of the invention further includes: after the target gear is put into gear, the transmission control unit controls the clutch to be combined to a preset grinding position, when the clutch is combined to the preset grinding position, the transmission control unit calculates a recovery target torque and generates a torque reduction recovery request, and the transmission control unit sends the torque reduction recovery request and the recovery target torque to the CAN bus and controls the clutch to be combined according to the recovery target torque. The electronic control unit receives the torque reduction recovery request, determines the output torque of the engine, and controls the lifting torque of the engine according to the output torque of the engine, wherein the output torque of the engine is the smaller one of the recovery target torque and the engine torque value obtained according to the second accelerator information and a preset accelerator torque curve; the vehicle controller responds to the torque reduction recovery request, calculates the recovery motor compensation torque according to the vehicle demand torque and the engine output torque, and sends the recovery motor compensation torque to the CAN bus; the motor controller reduces the motor compensation torque according to the motor compensation torque recovery until the motor compensation torque is 0, so that the engine recovery is realized, and the smoothness during gear shifting can be improved.

When the torque of the engine is controlled to be recovered, the gearbox control unit acquires second accelerator information and obtains a torque recovery rate according to the second accelerator information and a preset torque recovery speed table, wherein the torque recovery rate can be calibrated through a rack, a two-dimensional table of the torque recovery rate is determined according to accelerator opening and accelerator opening change rate, the torque recovery rate is obtained through a table look-up method, and the recovery target torque of the engine is gradually increased according to the torque recovery rate so as to improve the output torque of the engine and enable the output torque of the engine to be recovered to the torque before gear shifting.

Specifically, as shown in fig. 2, when the TCU determines that the target gear engagement is completed, the TCU transmits a recovery target torque to the ECU through the CAN bus, and the TCU transmits the recovery target torque to limit acceleration shock caused by too fast rise of the engine torque. And after the target gear is engaged, the TCU acquires second accelerator information and obtains the torque recovery rate of torque reduction through a table look-up method, and the recovery target torque sent by the TCU is increased according to the torque recovery rate on the basis of the torque at the previous moment. When the recovery target torque is greater than the maximum allowable torque value of the engine allowed output, the TCU transmits the torque down recovery flag invalid value of 0 and keeps the transmitted value equal to the maximum allowable torque value of the engine. As shown in fig. 3, the second curve S202 is a transmission actual gear change curve showing the actual gear of the engine after the gear shift at time point t4, and as shown in the third curve S203, during the engine recovery torque phase, the recovery target torque delivered by the TCU is gradually increased to the maximum allowable torque value of the engine at the target gear during the period t4-t 5.

The engine ECU compares the received recovery target torque with the engine torque value obtained by the second accelerator information and the preset accelerator torque curve, takes the smaller value of the two as the engine output torque, and smoothes the engine output torque at the time before and after the engine, as shown in fig. 3, where the engine torque smoothly rises during the time period t4-t5 of the fourth curve S204.

And when the TCU sends the recovery target torque, the VCU controls the motor compensation torque value to be reduced along with the increase of the output torque of the engine until the motor compensation torque is 0, and the VCU terminates the motor torque compensation. As shown in fig. 3, in the fifth curve S205, during the time period t4-t5, the motor compensation torque gradually decreases, the total motor torque slowly decreases until the engine recovery torque, the motor compensation torque is 0, the motor operates at the target motor torque in the current gear, and the motor torque is smooth.

The TCU commands clutch engagement while sending the recovery target torque. The clutch is quickly combined to a preset sliding position, and then is gradually combined to a target combination position corresponding to the recovery target torque, the target position is calculated according to the recovery target torque calibrated by the rack and a clutch torque transmission characteristic table, and the clutch is controlled to be combined to the target combination position from the preset grinding position until the clutch is completely combined. As shown in FIG. 3, in a sixth curve S206, during the time period t4-t5, the clutch position curve rises quickly and then rises slowly, i.e., the clutch is engaged quickly and then engaged slowly, the engine torque is matched with the clutch engagement position until the clutch is fully engaged, and the shift control is finished.

Based on the shift control process of the above embodiment, fig. 4 is a flowchart of a shift control method according to an embodiment of the present invention, including the following steps.

S10, the TCU determines that the vehicle satisfies the shift condition.

And S11, the TCU calculates the torque reduction target torque according to the first accelerator information and the initial value of the gear shifting torque of the engine, and sends the torque reduction request of the engine and the torque reduction target torque.

S12, the ECU and VCU judge whether receiving the engine torque-down request, if yes, executing step S13, if no, continuing the step S12.

And S13, the ECU controls the unloading torque of the engine according to the torque reduction target torque, the VCU responds to the torque reduction request of the engine to calculate the motor compensation torque, and the motor controller controls the motor lifting torque according to the motor compensation torque.

And S14, the TCU calculates a target separation position according to the torque reduction target torque and controls the clutch to be separated to the target separation position.

S15, the TCU judges whether the torque-reducing target torque reaches the gear-shifting torque threshold value, if yes, the step S16 is executed, and if not, the step S14 is continued.

S16, the TCU controls the clutch to quickly disengage to a maximum disengaged position.

And S17, when the clutch is separated to the maximum separation position, the gear shifting mechanism is switched to the target gear.

And S18, the TCU detects that the target gear is completely engaged, and controls the clutch to be combined to a preset sliding friction position.

S19, after the clutch is engaged to the preset slip position, the TCU calculates a recovery target torque and generates a torque-down recovery request.

S20, the TCU sends a recovery target torque and a torque reduction recovery request to the CAN bus, and controls the clutch to be combined according to the recovery target torque.

And S21, the ECU receives the torque reduction and recovery request, determines the output torque of the engine, and controls the lifting torque of the engine according to the output torque of the engine, wherein the output torque of the engine is the smaller one of the recovery target torque and the engine torque value obtained according to the second accelerator information and a preset accelerator torque curve.

And S22, the vehicle controller responds to the torque reduction recovery request, calculates the recovery motor compensation torque according to the vehicle demand torque and the engine output torque, and sends the recovery motor compensation torque to the CAN bus.

And S23, the motor controller reduces the motor compensation torque according to the recovered motor compensation torque until the motor compensation torque is 0.

And S24, finishing the gear shifting process.

In summary, the gear shifting control method provided by the embodiment of the invention is suitable for a hybrid driving mode in which an engine and a motor participate in driving at the same time, and the transmission, the motor and the engine are dynamically and jointly controlled based on the CAN bus. After the transmission control unit TCU judges that the vehicle meets the gear shifting condition, the gear shifting control can be carried out in a clutch separation stage and a clutch combination stage.

In the clutch separation stage, in order to enable the output torque of the engine to be matched with the transmission torque of the clutch, the TCU sends an engine torque reduction request mark and a torque reduction target torque to the CAN bus. And according to the definition of the CAN message, transmitting a numerical value 1 when the torque reduction request mark is effective, and transmitting a numerical value 0 when the torque reduction request mark is ineffective. The ECU responds to a torque reduction request of the TCU when receiving a torque reduction request flag of 1, the unloading torque of the engine is controlled according to a torque reduction target torque, the VCU calculates a motor compensation torque when receiving the torque reduction request flag of 1, the motor compensation torque is sent to the motor controller MCU, and the gear shifting power compensation is realized by utilizing the quick response characteristic of the motor.

And, the clutch control and engine control strategy may be divided into two steps. Firstly, the TCU receives torque-down target torque sent to the CAN bus by the ECU in real time, and the clutch is separated to a target separation position corresponding to the current torque-down target torque. Secondly, when the TCU receives that the torque-reducing target torque is reduced to be smaller than a gear-shifting torque threshold value for allowing the clutch to be completely separated, the TCU controls the clutch to be rapidly separated to a maximum separation position. When the clutch is separated to the maximum separation position, the TCU controls the gear before the gear engaging executing mechanism is removed, and the gear shifting target gear is engaged.

In the clutch combination stage, the process that the TCU requests engine torque to recover and controls the clutch to combine is included, specifically, after the TCU judges that the transmission is connected with a gear shifting target gear, the TCU sends recovery target torque to the ECU through the CAN bus, and the ECU controls the engine torque to rise. And the TCU controls the clutch to be combined to a target combination position corresponding to the current recovery target torque, so that the recovery target torque is matched with the clutch transmission torque, the motor compensation torque requested by the VCU is gradually reduced until the motor compensation torque is 0, the power compensation is finished, and the gear shifting is finished.

In summary, the shift control method according to the embodiment of the present invention implements coordination strategy and algorithm control of the transmission, the motor, and the engine based on the CAN bus. Engine torque is actively controlled by a transmission control unit TCU by sending a torque down request and a torque down recovery request during a shift. And the motor is adopted to compensate the reduced torque of the engine by utilizing the quick response characteristic of the motor. And the TCU controls the clutch to be matched with the engine torque according to the target torque, so that the noise of the rapid rise of the engine rotating speed in the gear shifting process can be avoided, the phenomenon of engine braking can be prevented, the impact degree in the gear shifting process of the AMT is effectively reduced, and the gear shifting quality and smoothness of the vehicle are improved.

Based on the method of the above embodiment, the second aspect embodiment of the invention also proposes a vehicle, and as shown in fig. 5, the vehicle 1 of the embodiment of the invention includes an engine 10, an electric machine 20, a transmission 30, a vehicle controller 40, and a CAN bus 50. The CAN bus 50 is connected to the engine 10, the motor 20, the transmission 30, and the vehicle controller 40, respectively.

In the embodiment, the engine 10 includes the electronic control unit 11, the motor 20 includes the motor controller 21, the transmission 30 includes the transmission control unit 31, and the transmission control unit 31, the electronic control unit 11, the vehicle controller 40, and the motor controller 21 perform information interaction through the CAN bus 50 to implement the gear shifting control method of the above embodiment, and the specific control process may refer to the description of the above embodiment.

According to the vehicle 1 provided by the embodiment of the invention, the information interaction is carried out through the transmission control unit 31, the electronic control unit 11, the vehicle control unit 40 and the motor controller 21 through the CAN bus 50, so that the gear shifting control method provided by the embodiment CAN be realized, the smoothness during gear shifting CAN be improved, the gear shifting noise and the pause and contusion CAN be reduced, and the comfort is improved.

In the description of this specification, any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of custom logic functions or processes, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A shift control method characterized by comprising:

the transmission control unit calculates a torque reduction target torque according to first accelerator information and a gear shifting torque initial value of an engine, generates an engine torque reduction request, and sends the engine torque reduction request and the torque reduction target torque to a CAN bus;

the electronic control unit responds to the engine torque reduction request and controls the engine unloading torque according to the torque reduction target torque;

the vehicle control unit responds to the torque reduction request of the engine, calculates motor compensation torque, sends the motor compensation torque to a motor controller through a CAN bus, and the motor controller controls the motor to lift the torque according to the motor compensation torque; and

and the transmission control unit adjusts the separation position of the clutch according to the torque-reducing target torque until the clutch is separated to the maximum separation position, and controls the gear shifting mechanism to be switched to the target gear.

2. The shift control method according to claim 1, wherein the transmission control unit calculating a torque down target torque from the first throttle information and a shift torque initial value of the engine includes:

the transmission control unit calculating a first torque down rate and a second torque down rate according to the first throttle information and a shift torque initial value of the engine, wherein the first torque down rate is smaller than the second torque down rate;

the transmission control unit determines the torque-down target torque according to the first torque-down rate, and determines the torque-down target torque according to the second torque-down rate when the torque-down target torque falls to a first torque threshold until the torque-down target torque falls to a shift torque threshold.

3. The shift control method of claim 2, wherein the transmission control unit calculating a first torque down rate and a second torque down rate from the first throttle information and a shift torque initial value of the engine comprises:

the transmission control unit obtains a first torque reduction time and a second torque reduction time according to the opening degree of an accelerator, wherein the first accelerator information comprises the opening degree of the accelerator and the change information of the opening degree of the accelerator;

the transmission control unit calculating the first torque down rate from the initial value of the shift torque and the first down time;

the transmission control unit corrects the second torque reduction time according to the accelerator opening change information to obtain second torque reduction correction time;

the transmission control unit calculates the second torque down rate based on the initial value of the shift torque and the second torque down correction time.

4. The shift control method according to claim 3, wherein the transmission control unit corrects the second torque down time according to accelerator opening degree change information to obtain a second torque down correction time, including:

the transmission control unit reduces the second torque reduction time by a preset time period when the accelerator opening is increased so as to obtain a second torque reduction correction time;

alternatively, the transmission control unit may set the second torque down time as the second torque down correction time when the accelerator opening degree is constant or decreased.

5. The shift control method of claim 1, wherein the vehicle control unit calculating a motor compensation torque comprises:

the vehicle controller calculates a torque difference value between the vehicle demand torque and the torque reduction target torque;

the vehicle control unit calculates a quotient of the torque difference value and a gear speed ratio of the motor to obtain torque required by the motor;

and the vehicle control unit calculates the difference value between the torque required by the motor and the current torque of the motor so as to obtain the motor compensation torque.

6. The shift control method according to claim 1, wherein the transmission control unit adjusts the disengagement position of the clutch according to the torque-down target torque until the clutch is disengaged to the maximum disengagement position, including:

the gearbox control unit calculates and obtains a target separation position according to the torque reduction target torque and the clutch torque transmission characteristic table;

the gearbox control unit controls the clutch to be separated to the target separation position;

and when the torque reduction target torque reaches a gear shifting torque threshold value, the gearbox control unit is used for separating the clutch to a maximum separation position.

7. The shift control method according to claim 1, characterized by further comprising:

when the target gear is completely engaged, the transmission control unit controls the clutch to be combined to a preset sliding position, and after the clutch is combined to the preset sliding position, the transmission control unit calculates a recovery target torque and generates a torque reduction recovery request;

the transmission control unit sends the torque reduction recovery request and a recovery target torque to the CAN bus and controls the clutch to be combined according to the recovery target torque;

the electronic control unit receives the torque reduction recovery request, determines an engine output torque, and controls an engine to raise the torque according to the engine output torque, wherein the engine output torque is the smaller one of the recovery target torque and an engine torque value obtained according to the second accelerator information and a preset accelerator torque curve;

the vehicle controller responds to the torque reduction recovery request, calculates the recovery motor compensation torque according to the vehicle required torque and the engine output torque, and sends the recovery motor compensation torque to the CAN bus;

and the motor controller reduces the motor compensation torque according to the recovered motor compensation torque until the motor compensation torque is 0.

8. The shift control method according to claim 7, wherein the transmission control unit calculating a recovery target torque includes:

the transmission control unit acquires second accelerator information, acquires a torque recovery rate according to the second accelerator information and a preset torque recovery rate table, and calculates a recovery target torque according to the current engine torque and the torque recovery rate.

9. The shift control method according to claim 7, wherein the transmission control unit controlling the clutch engagement according to the recovery target torque includes:

and the transmission control unit calculates and obtains a target combination position according to the recovery target torque and the clutch torque transmission characteristic table, and controls the clutch to be combined from the preset sliding position to the target combination position until the clutch is completely combined.

10. A vehicle is characterized by comprising an engine, a motor, a transmission, a vehicle control unit and a CAN bus, wherein the CAN bus is respectively connected with the engine, the motor, the transmission and the vehicle control unit, the engine comprises an electronic control unit, the motor comprises a motor controller, the transmission comprises a transmission control unit, and the transmission control unit, the electronic control unit, the vehicle control unit and the motor controller perform information interaction through the CAN bus so as to realize the gear shifting control method according to any one of claims 1 to 9.