CN109094553B

CN109094553B - Hybrid electric vehicle and engine starting control method thereof

Info

Publication number: CN109094553B
Application number: CN201811039607.5A
Authority: CN
Inventors: 罗荣华; 翟钧; 蒲斌; 熊忠林; 林富
Original assignee: Chongqing Changan Automobile Co Ltd
Current assignee: Chongqing Changan Automobile Co Ltd
Priority date: 2018-09-06
Filing date: 2018-09-06
Publication date: 2020-07-10
Anticipated expiration: 2038-09-06
Also published as: CN109094553A

Abstract

The invention provides an engine starting control method of a hybrid electric vehicle, the hybrid electric vehicle works in a pure electric mode, when an engine needs to be started to provide power due to external environment or insufficient power and a double-clutch gearbox needs to be shifted, the action sequence of the engine starting process and the action sequence of the engine shifting process are simultaneously coordinated and controlled, the characteristic that a motor is in a sliding friction state when being closed to a preset position through an engine clutch is utilized, and when the gear of the double-clutch gearbox is switched, a first clutch and a second clutch in the double-clutch gearbox are in the sliding friction state when being switched, and the engine clutch and the double-clutch gearbox simultaneously slide and rub to absorb impact, so that the impact problem in the power switching process of the hybrid electric vehicle is solved. The invention also provides a hybrid electric vehicle.

Description

Hybrid electric vehicle and engine starting control method thereof

Technical Field

The invention relates to the technical field of hybrid electric vehicles, in particular to a hybrid electric vehicle and an engine starting control method thereof.

Background

With the exhaustion of renewable resources, in order to reduce energy consumption and reduce pollution, the design and development of new energy vehicles such as energy-saving plug-in hybrid vehicles and the like are more and more concerned by various automobile manufacturers in the world.

The double-clutch transmission has the characteristics of rapid gear shifting, no power interruption, high power transmission efficiency and the like, and is widely applied to hybrid electric vehicles. When the vehicle needs to be switched from the pure electric driving mode to the hybrid driving mode in the running process, the engine needs to be started quickly, and power impact can be generated at the moment of starting the engine. There is also a slight power shock to the vehicle when shifting gears in the transmission. And the processes of starting the engine and shifting the gear of the gearbox are controlled quite complicated, particularly the control on the clutch is complicated, and the engine and the gearbox cannot be simultaneously controlled. Therefore, the ride control of the parallel hybrid vehicle equipped with the double clutch transmission is extremely difficult.

Therefore, how to solve the impact problem in the power switching process of the hybrid electric vehicle is a problem to be urgently solved by those skilled in the art.

Disclosure of Invention

In view of this, the present invention provides an engine start control method for a hybrid electric vehicle to solve the impact problem during the power switching process of the hybrid electric vehicle.

In order to achieve the purpose, the invention provides the following technical scheme:

an engine starting control method of a hybrid electric vehicle is used for switching a pure electric working condition of a power system driven by a motor to a hybrid working condition of synchronous driving of the motor and an engine and simultaneously carrying out gear shifting of a double-clutch gearbox, and comprises the following steps:

step 1) judging whether the rotating speed synchronization of the double-clutch gearbox and the motor is prior to the torque switching between an original gear and a target gear of the double-clutch gearbox;

step 2) if not, controlling the torque switching of the original gear and the target gear of the double-clutch gearbox, and entering step 3);

step 3) if yes, controlling the engine to start, and controlling the started engine to be synchronous with the rotating speed of the motor;

step 4) controlling the rotation speed of the motor to be synchronous with the rotation speed of a target shaft of a target gear of the double-clutch gearbox after the rotation speeds of the engine and the motor are synchronous;

step 5) judging whether the torque exchange between the original gear and the target gear of the double-clutch gearbox is finished or not, if so, finishing; and if not, controlling the torque switching of the original gear and the target gear of the double-clutch gearbox, and ending.

Preferably, in the engine start control method, the step 2) is specifically to control a reduction of a first clutch clamping force corresponding to an original gear of the dual clutch transmission, and control an increase of a second clutch clamping force corresponding to a target gear of the dual clutch transmission, and when the first clutch clamping force corresponding to the original gear is lower than a first preset threshold value and the second clutch clamping force corresponding to the target gear is greater than a second preset threshold value, the torque exchange of the dual clutch transmission is completed.

Preferably, in the engine start control method described above, the step 3) includes:

step 31) the engine clutch controller controls the engine clutch to move towards the closing direction according to a preset slope until the engine clutch moves to the starting rotating speed for dragging the engine to achieve oil injection and ignition;

step 32) when the engine management system monitors that the rotating speed of the engine reaches the rotating speed threshold value of the starting rotating speed, controlling the engine to perform oil injection and ignition, and sending ignition success information;

and step 33) after the vehicle control unit receives the information that the ignition of the engine is successful, controlling the engine clutch to rapidly move to a closed position, and completing the rotation speed synchronization of the engine and the motor.

Preferably, in the engine start control method, the step 31) further includes, after the vehicle control unit receives the rotation speed synchronization information sent by the dual clutch transmission controller, sending a control instruction of rotation speed synchronization to the engine clutch controller.

Preferably, in the engine start control method of the hybrid vehicle, the step 4) further includes:

step 41) the double-clutch transmission controller receives information of engine starting completion and judges the rotation speed difference between the motor and the target shaft;

step 42) when the rotating speed of the motor is lower than that of the target shaft, the double-clutch transmission controller sends a power source torque increasing request to the whole vehicle controller to realize the active increase of the rotating speed of the motor end;

and 43) when the rotating speed of the motor is higher than that of the target shaft, the double-clutch transmission controller sends a power source torque reduction request to the whole vehicle controller to realize the active reduction of the rotating speed of the motor end and complete the synchronization of the rotating speed of the motor and the rotating speed of the double-clutch transmission.

Preferably, in the engine start control method, the step 1) is preceded by:

step 01), the vehicle controller judges whether the engine needs to be started to be switched from the pure electric driving mode to the hybrid power driving mode according to the state of the vehicle power system;

step 02), after the vehicle control unit judges that the engine needs to be started, the vehicle control unit and a dual-clutch transmission controller confirm whether the dual-clutch transmission is arranged for gear shifting;

and 03) if yes, the double-clutch gearbox controller moves a gear shifting fork to a gear pair corresponding to the target gear and locks the gear shifting fork.

Preferably, in the engine start control method, the shift confirmation information of the dual clutch transmission controller includes a current gear of the dual clutch transmission, motor speed information, and accelerator pedal opening information.

Preferably, in the engine start control method, the criterion of the step 1) is information on an opening degree of the accelerator pedal, and the method includes:

when the opening degree of the accelerator pedal is higher than a preset pedal threshold value and the gear is to be shifted up, firstly carrying out torque exchange of the double-clutch gearbox;

when the opening degree of the accelerator pedal is higher than the preset threshold value of the pedal and the gear is to be shifted down, firstly synchronizing the rotating speed;

when the opening degree of the accelerator pedal is lower than the preset pedal threshold value and the gear is to be shifted up, firstly carrying out rotation speed synchronization;

and when the opening degree of the accelerator pedal is lower than the preset threshold value of the pedal and the gear is to be downshifted, firstly carrying out torque exchange of the double-clutch gearbox.

Preferably, in the engine start control method, after the step 31), a motor output torque protection mechanism is further provided, and the method includes:

step 310), the engine clutch controller detects the current actual stroke of the engine clutch in real time, converts the actual stroke into a real-time torque in the starting process of the engine, and feeds back the real-time torque signal to the vehicle control unit;

and 311), the vehicle control unit receives the real-time torque signal and controls the motor to additionally output a compensation torque for dragging the engine to act until the engine reaches the starting rotating speed.

A hybrid electric vehicle comprises an engine and a motor which are arranged in parallel, and a double-clutch gearbox for gear shifting control, and is characterized in that when the double-clutch gearbox is shifted, and the engine and the motor are switched from pure electric to hybrid drive, the engine starting control method is adopted.

The invention provides an engine starting control method of a hybrid electric vehicle, which is used for switching a pure electric working condition of a power system driven by a motor to a hybrid working condition driven by the motor and the engine synchronously and needing to shift gears of a double-clutch gearbox, and comprises the following control steps:

step 1) judging whether the rotating speed synchronization of the double-clutch gearbox and the motor is prior to the torque switching between the original gear and the target gear of the double-clutch gearbox;

step 5) judging whether the torque exchange between the original gear and the target gear of the double-clutch gearbox is finished or not, and if so, finishing; and if not, controlling the torque switching of the original gear and the target gear of the double clutch, and ending. The hybrid electric vehicle works in a pure electric mode, when an engine needs to be started to provide power due to external environment or insufficient power and the dual-clutch gearbox needs to be shifted, in order to avoid the impact of the engine starting process and the shifting process, the action sequence of the engine starting process and the shifting process is coordinated and controlled, the characteristic that a motor is closed to a preset position through an engine clutch and is in a sliding state is utilized, and when the gears of the dual-clutch gearbox are switched, a first clutch and a second clutch inside the dual-clutch gearbox are in the sliding state during switching, and the impact in the shifting process is absorbed by the engine clutch and the dual-clutch gearbox through simultaneous sliding, so that the impact problem in the power switching process of the hybrid electric vehicle is solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a power system layout structure of an engine start control method for a hybrid electric vehicle according to the present invention;

FIG. 2 is a control flow chart of the rotation speed synchronization and the torque exchange in the engine starting control method of the new energy automobile provided by the invention;

FIG. 3 is a control flow diagram of the engine and motor speed synchronization of FIG. 2;

FIG. 4 is a control flow chart illustrating the rotational speed synchronization between the motor and the dual clutch transmission of FIG. 2;

FIG. 5 is a flow chart illustrating the transition confirmation from pure electric to hybrid in FIG. 2;

fig. 6 is a system control flowchart of an engine start control method of a new energy vehicle according to the present invention.

Detailed Description

The invention discloses an engine starting control method of a hybrid electric vehicle, which solves the impact problem in the power switching process of the hybrid electric vehicle.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, fig. 1 is a schematic diagram of a layout structure of a powertrain of an engine start control method for a hybrid electric vehicle according to the present invention; fig. 2 is a control flowchart of the rotation speed synchronization and the torque exchange in the engine start control method of the new energy automobile provided by the invention.

Hybrid vehicles with a parallel configuration generally include, as powertrain components, an internal combustion engine 1, an engine Management System 5 (EMS, Energy Management System), an engine clutch 2, an engine clutch controller 6 (ACU, Actuator Control Unit, also known as coupling mechanism controller, which is called engine clutch controller for characterizing its function), an electric machine 3, an electric machine controller 7 (IPU, Intelligent Power Unit, which is called motor controller in general, a dual clutch transmission 4, a dual clutch transmission controller 8 (TCU, TransmissionControl Unit) and a Vehicle controller 9 (VCU, Vehicle Control Unit)

The embodiment provides an engine starting control method of a hybrid electric vehicle, when an engine 1 needs to be started and a double-clutch gearbox 4 needs to be shifted, the engine 1 is used for starting and the double-clutch gearbox 4 is used for shifting simultaneously, and the impact generated by the engine 1 and the double-clutch gearbox 4 is absorbed by the sliding state of the engine clutch 4 in the starting process of the engine 1. The gear shifting process of the double-clutch transmission 4 comprises two parts, namely torque exchange in the gear shifting process of the double-clutch transmission, and synchronization of the rotating speed of the motor 3 and the rotating speed of a target shaft of the double-clutch transmission 4 after the double-clutch transmission is shifted to a target gear, wherein the torque exchange and the rotation speed synchronization can be adjusted according to action time sequences of a working condition state and a working condition state of the hybrid electric vehicle, the following introduction of specific control steps is used for explaining the control process, and the control time sequences can be exchanged:

step 1) judging whether the rotating speed synchronization of the double-clutch gearbox and the motor is prior to the torque switching between the original gear and the target gear of the double-clutch gearbox.

After the engine 1 is started and confirmed, the double-clutch gearbox controller 8 confirms whether the running state of the whole vehicle can meet the running requirement of the whole vehicle or not according to the running state of the whole vehicle, if the running state meets the requirement, the engine is started to provide enough power, and gear shifting is not needed. When the requirement is not met, the torque output by the whole vehicle is insufficient, the double-clutch transmission 4 is required to perform gear shifting operation to provide enough torque in the running process of the vehicle, the starting work of the engine 1 and the gear shifting work of the double-clutch transmission 4 are performed simultaneously, and the impact problem of synchronous action of the engine 1 and the double-clutch transmission needs to be solved. No matter the torque exchange or the rotating speed synchronization sequence, the torque exchange or the rotating speed synchronization sequence needs to be informed to a VCU (vehicle control unit) through a TCU (transmission control unit) of the double-clutch gearbox, the rotating speeds of the double-clutch gearbox 4 and the motor 3 are controlled to be synchronized, and the vehicle control unit starts to control the rotating speeds synchronously.

After the double-clutch transmission 4 confirms that the gear shifting operation is needed, the working time sequence of synchronous rotation speed and torque exchange under the current working condition is judged, and the matching of the output torque of the double-clutch transmission 4 and the output torque of the motor 3 is carried out to ensure that the running condition of the vehicle is met through the adaptation of the torques when the vehicle needs to improve the torque or reduce the torque.

And 2) if not, controlling the torque switching of the original gear and the target gear of the double-clutch gearbox, and entering the step 3).

If not, the running state of the vehicle is described, the condition that the vehicle is prior to the rotating speed synchronization is not met, the torque is switched from the original gear to the target gear through the double-clutch gearbox, and then the rotating speed synchronization work is carried out.

And 3) if yes, controlling the engine to start, and controlling the started engine to be synchronous with the rotating speed of the motor.

Otherwise, the rotation speed of the engine and the motor can be synchronized, and after the hybrid electric vehicle is switched from the pure electric mode to the hybrid driving mode, the gear shifting driving of the double-clutch gearbox is carried out.

And 4) after the rotating speeds of the engine and the motor are synchronous, controlling the rotating speed of the motor to be synchronous with the rotating speed of a target shaft of a target gear of the double-clutch gearbox.

The rotating speed synchronization of the engine and the motor comprises a starting process of the engine, after the engine is started, the synchronous action of the engine and the motor is used for power output, and the output synchronization is carried out on a target shaft correspondingly through the target shaft of the double-clutch gearbox and a target gear of gear shifting of the double-clutch gearbox, so that the rotating speed synchronization and the power output are carried out.

Step 5) judging whether the torque exchange between the original gear and the target gear of the double-clutch gearbox is finished or not, and if so, finishing; and if not, controlling the torque switching of the original gear and the target gear of the double-clutch gearbox, and ending.

Because the rotating speeds of the engine and the motor act synchronously, whether the double-clutch gearbox shifts gears first or not needs to be judged and selected in advance, and therefore secondary judgment is carried out on torque switching after the rotating speeds are synchronous, and synchronous completion of the rotating speed synchronization of the engine and the motor and the torque switching of the double-clutch gearbox is guaranteed.

The hybrid electric vehicle works in the pure electric mode, when an engine needs to be started to provide power due to external environment or insufficient power and the dual-clutch gearbox needs to be shifted, in order to avoid the impact of the engine starting process and the shifting process, the action sequence of the engine starting process and the shifting process is coordinated and controlled, the characteristic that the motor is closed to a preset position through an engine clutch and is in a sliding friction state is utilized, and when the gears of the dual-clutch gearbox are switched, a first clutch and a second clutch inside the dual-clutch gearbox are in the sliding friction state when being switched, and the impact in the shifting process is absorbed by the engine clutch and the dual-clutch gearbox in a sliding friction mode simultaneously, so that the impact problem in the power switching process of the hybrid electric vehicle is solved.

In a specific embodiment of the present disclosure, the step 2) is specifically to control a reduction of a first clutch clamping force corresponding to an original gear of the dual clutch transmission, and control an increase of a second clutch clamping force corresponding to a target gear of the dual clutch transmission, and when the first clutch clamping force corresponding to the original gear is lower than a first preset threshold value and the second clutch clamping force corresponding to the target gear is greater than a second preset threshold value, the torque exchange of the dual clutch transmission is completed.

When the double-clutch gearbox 4 needs to shift gears, the double-clutch gearbox 4 is switched to a target gear from an original gear, the process of gear switching corresponds to the transmission torque of different gears, and finally the exchange of the transmission torque is completed. The double-clutch gearbox 4 is corresponding to a first clutch to transmit torque in an original gear, a second clutch corresponding to a target gear is controlled to be closed during gear shifting, meanwhile, the first clutch is controlled to be opened, the clamping force of the first clutch is gradually reduced in the gear shifting process, and the clamping force of the corresponding second clutch is gradually increased.

And when the clamping force of the first clutch and the clamping force of the second clutch meet the threshold requirement in the torque exchange process of the double-clutch transmission 4, the double clutches are determined to finish gear shifting, namely the torque exchange of the double-clutch transmission is finished.

The engine 1 carries out the output of hybrid vehicle power jointly through engine clutch 2 and the motor 3 of parallel arrangement after the start, because the output torque of motor 3 changes in the process of shifting, the increase or reduce change can appear in the torque output after shifting, correspondingly, can exert an influence to motor 3 rotational speed, consequently according to the actual conditions of torque change, judge whether motor 3 needs in advance with the rotational speed synchronization of target axle, avoid the torque change to arouse the problem that power is not enough or assault greatly.

As shown in fig. 3, fig. 3 is a control flow chart of the engine and motor speed synchronization in fig. 2.

In an embodiment of the present disclosure, the step 3) includes:

and step 31) the engine clutch controller controls the engine clutch to move towards the closing direction according to the preset slope until the engine clutch moves to the starting rotating speed for dragging the engine to reach the oil injection ignition.

In the process of starting the engine 1, the engine 1 is dragged to a certain rotating speed in advance and then oil injection and ignition are carried out, so that the starting difficulty of the engine 1 from a static state to a working state is reduced. The dragging of the rotating speed of the engine 1 is powered by the motor 3, and the engine 1 is driven to rotate by transmitting torque through the closing of the engine clutch 2. In the process that the engine clutch 2 is gradually closed, the motor 3 drags the engine 1 to reach the starting rotating speed, the closing of the engine clutch 2 is gradually closed according to a certain slope, and the difficulty of the motor 3 dragging the engine 1 is reduced

And step 32) when the engine management system monitors that the rotating speed of the engine reaches the rotating speed threshold value of the starting rotating speed, controlling the engine to perform oil injection and ignition, and sending ignition success information.

And step 33) after the vehicle control unit receives the information that the ignition of the engine is successful, controlling the clutch of the engine to rapidly move to a closed position, and completing the rotation speed synchronization of the engine and the motor.

The engine management system 5 monitors ignition success information of the engine 1 and sends the information to the vehicle control unit 9, and after receiving the ignition success information, the vehicle control unit 9 sends an instruction to the engine clutch controller 6 to request the engine clutch controller to quickly close the engine clutch 2. The engine management system (VCU)5 monitors the ignition success information of the engine 1, which may be set as a rotational speed threshold to be reached when the engine 1 can ignite smoothly, within which the engine can ignite smoothly with minimum ignition shock. The working state of the engine 1 is monitored by an engine management system 5, the engine 1 is started and finishes transmitting working power through an engine clutch 2, so that the engine clutch 2 needs to be completely closed to reduce abrasion and energy loss of the engine clutch 2, the process is monitored by the engine management system 5 in real time, and the engine management system and a vehicle controller 9 cooperate to realize starting control of the engine 1.

In a specific embodiment of the present disclosure, the step 31) further includes sending a control instruction of rotating speed synchronization to the engine clutch controller after the vehicle controller receives the rotating speed synchronization information sent by the dual clutch transmission controller.

The TCU informs the VCU of the vehicle control unit, the VCU controls the speed of the double-clutch gearbox 4 to be synchronous with the motor 3, and the VCU starts to control the speed to be synchronous.

As shown in fig. 4, fig. 4 is a control flow chart of the motor and the dual clutch transmission in fig. 2 for synchronizing the rotation speed.

In an embodiment of the present disclosure, the step 4) further includes:

and step 41) the double-clutch transmission controller receives the information of the completion of the starting of the engine and judges the rotating speed difference between the motor and the target shaft.

Step 42) when the rotating speed of the motor is lower than that of the target shaft, the double-clutch gearbox controller sends a power source torque increasing request to the whole vehicle controller to realize the active increase of the rotating speed of the motor end;

and 43) when the rotating speed of the motor is higher than that of the target shaft, the double-clutch gearbox controller sends a power source torque reduction request to the whole vehicle controller to realize the active reduction of the rotating speed of the motor end and complete the synchronization of the rotating speed of the motor and the rotating speed of the double-clutch gearbox.

After the engine 1 is completely started, the output power drives the hybrid electric vehicle to act through the dual-clutch transmission 4, the engine clutch controller 6 monitors the working state of the engine clutch 2 and feeds back closing information to the vehicle control unit 9, and the vehicle control unit 9 controls the dual-clutch transmission 4 in time according to the working states of the engine 1 and the engine clutch 2 at the moment, so that the normal output of the power is ensured.

After receiving the information of the completion of the engine starting, the controller of the dual-clutch transmission 4 sends a power source torque-increasing request to the vehicle control unit to realize the active increase of the rotating speed of the motor end, or sends a power source torque-decreasing request to the vehicle control unit to realize the active decrease of the rotating speed of the motor end, so that the synchronization of the rotating speed of the motor and the rotating speed of the dual-clutch transmission is completed.

After the engine is started, the engine outputs the working power of the whole vehicle, the engine outputs the power through the engine clutch and the double-clutch gearbox, the engine and the motor work simultaneously in the hybrid vehicle with the parallel structure, and the power output by the engine is transmitted to the double-clutch gearbox through the motor, so that the motor and the double-clutch gearbox are required to rotate synchronously to output the power.

The engine is started according to the power requirement of the whole vehicle, the engine and the motor are mixed to output power, the double-clutch gearbox is shifted according to the working condition of the whole vehicle, the double-clutch gearbox comprises two conditions of downshifting or upshifting, and correspondingly, the rotating speed of the motor comprises two conditions of rotating speed increase or rotating speed increase. When the vehicle controller judges the change of the vehicle working condition according to the working condition, the gear shifting condition of the double-clutch gearbox, when the target shaft rotating speed of the double-clutch gearbox is lower than the rotating speed of the original gear shaft, the vehicle controller sends a power source torque reduction request, the rotating speed of the driving motor end is actively reduced, otherwise, a power source torque increase request is sent, and the rotating speed of the driving motor end is actively increased, so that the rotating speeds of the motor and the double-clutch gearbox are actively controlled to be synchronous.

As shown in fig. 5, fig. 5 is a flow chart of confirmation of transition from pure electric to hybrid in fig. 2.

In an embodiment of the present disclosure, before the step 1), the method further includes:

and step 01), the vehicle controller judges whether the engine needs to be started to be switched from the pure electric driving mode to the hybrid power driving mode according to the state of the vehicle power system.

The working condition of the hybrid electric vehicle is monitored by the vehicle control unit 9, and when the hybrid electric vehicle works in the pure electric mode, the motor 3 provides working power. When the working condition of the whole vehicle changes, the vehicle control unit 9 judges that the engine 1 needs to be started to provide power, so that the hybrid electric vehicle is switched from the pure electric mode to the hybrid power driving mode.

And step 02), after the vehicle control unit judges that the engine needs to be started, the vehicle control unit and the dual-clutch transmission controller confirm whether the dual-clutch transmission is arranged for gear shifting.

After the engine 1 is started and confirmed, the double-clutch gearbox controller 8 confirms whether the running state of the whole vehicle can meet the running requirement of the whole vehicle or not according to the running state of the whole vehicle, if the running state meets the requirement, the engine is started to provide enough power, and gear shifting is not needed. When the requirement is not met, which indicates that the torque output by the whole vehicle is insufficient at the moment, the double-clutch transmission 4 is required to perform gear shifting operation so as to provide enough torque during the running process of the vehicle.

Adapt to the work structure of two separation and reunion gearboxes 4, when needs shift gears, the shift fork of shifting moves in advance to the gear pair that the target gear corresponds to lock, in order to reduce the impact of shifting gears.

In an embodiment of the present disclosure, the shift confirmation information of the dual clutch transmission controller includes a current gear of the dual clutch transmission, information of a rotational speed of the motor, and information of an opening degree of an accelerator pedal.

In an embodiment of the present disclosure, the determining principle in step 1) is that the opening information of the accelerator pedal includes:

when the opening degree of an accelerator pedal is higher than a preset threshold value of the pedal and the gear is to be shifted up, firstly carrying out torque exchange of the double-clutch transmission;

when the opening degree of an accelerator pedal is higher than a preset threshold value of the pedal and the downshift is to be carried out, firstly carrying out rotation speed synchronization;

when the opening degree of an accelerator pedal is lower than a preset pedal threshold value and an upshift is to be carried out, firstly carrying out rotation speed synchronization;

and when the opening degree of an accelerator pedal is lower than a preset threshold value of the pedal and the gear is to be downshifted, firstly carrying out torque exchange of the double-clutch gearbox.

The opening information of the accelerator pedal is used as a control principle of torque exchange and synchronous time sequence of rotating speed, the pedal preset threshold value of the pedal preset position where the accelerator pedal is located is used as a judgment basis for carrying out different working conditions, so that the actual running state of the whole vehicle and the vehicle are combined by pure electric switching to hybrid power, the control logic of the hybrid electric vehicle is optimized, the impact caused by asynchronous vehicle state switching is further avoided, and the comfort is improved.

In an embodiment of the present disclosure, after step 31), a motor output torque protection mechanism is further provided, including:

step 310), the engine clutch controller detects the actual stroke of the current engine clutch in real time, converts the actual stroke into real-time torque in the starting process of the engine, and feeds back a real-time torque signal to the vehicle control unit;

and 310), the vehicle control unit receives the real-time torque signal and controls the motor to additionally output a compensation torque for dragging the engine to act until the engine reaches the starting rotating speed.

As shown in fig. 6, fig. 6 is a system control flowchart of an engine start control method of a new energy vehicle according to the present invention. The control flow charts of fig. 2-5 together form a system control flow chart for switching the pure electric drive to the hybrid drive of the hybrid electric vehicle.

In the process that the engine is dragged by the motor to reach the starting rotating speed, the motor needs to provide certain torque of the engine in real time, so that the torque output from the motor to the engine does not influence the normal power output of the hybrid electric vehicle, and a torque protection mechanism is arranged in the dragging process of the engine to ensure that the motor provides enough torque output.

The torque protection mechanism comprises torque confirmation for dragging an engine to act, a closing stroke of the engine clutch 2 is detected in real time by the engine clutch controller 6 and actual stroke information is fed back to the vehicle control unit 9, the vehicle control unit 9 coordinates with the motor controller 7 to control the motor 3 to output extra compensation torque, the compensation torque is extra torque of the motor under the condition that the normal operation of the vehicle is guaranteed, the engine clutch 2 is detected in the closing actual stroke, the actual stroke is converted into the real-time torque of the engine, and the aim of achieving the starting rotating speed of the engine by using the lowest motor power and reducing the starting difficulty is achieved through cooperation with the motor compensation torque.

When the motor drags the engine to operate, the normal output of the power of the whole vehicle needs to be ensured at the same time, the output torque is increased, the parameter of the compensation torque is set to be Tq _ cl, and the working torque parameter when the motor 3 drives the whole vehicle to maintain normal running is set to be Tq _ drv, so that the total torque output by the motor 3 is Tqem in the process that the engine 1 is dragged to the starting rotating speed, and the Tqem is Tq _ cl + Tq _ drv.

In an embodiment of the present disclosure, the engine clutch controller 6 converts the actual stroke into a real-time torque and outputs a torque signal, and the vehicle controller 9 receives the real-time torque signal and controls the motor 3 to output a compensation torque for dragging the engine 1 to a predetermined rotation speed. The actual stroke of the engine clutch 2 in the closing process corresponds to the transmission of different torque amounts, the engine clutch controller 6 converts the actual stroke into a real-time torque signal, the vehicle control unit 9 receives the real-time torque signal, outputs a control instruction to the motor controller 7, and outputs a compensation torque by the motor 3, so that the engine 1 can be dragged to the enough compensation torque of the preset rotating speed

Based on the engine starting control method for the hybrid electric vehicle, the invention also provides the hybrid electric vehicle which comprises the engine and the motor which are arranged in parallel and the double-clutch gearbox for gear shifting control, wherein when the double-clutch gearbox is used for gear shifting and the engine and the motor are switched from pure electric to hybrid drive, the engine starting control method is adopted.

The hybrid electric vehicle provided by the invention adopts the engine start control method of the hybrid electric vehicle provided by the embodiment, so that the beneficial effects brought by the engine start control method of the hybrid electric vehicle are shown in the embodiment.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An engine starting control method of a hybrid electric vehicle is used for switching a pure electric working condition of a power system driven by a motor to a hybrid working condition of synchronous driving of the motor and an engine and simultaneously carrying out gear shifting of a double-clutch gearbox, and is characterized by comprising the following steps of:

step 1) judging whether the rotating speed synchronization of the double-clutch gearbox and the motor is prior to the torque exchange between the original gear and the target gear of the double-clutch gearbox;

step 2) if not, controlling the torque exchange between the original gear and the target gear of the double-clutch gearbox, and entering step 3);

step 4) after the rotating speeds of the engine and the motor are synchronous, controlling the rotating speed of the motor to be synchronous with the rotating speed of a target shaft of the double-clutch transmission to a target gear;

step 5) judging whether the torque exchange between the original gear and the target gear of the double-clutch gearbox is finished or not, if so, finishing; and if not, controlling the torque exchange between the original gear and the target gear of the double-clutch gearbox, and ending.

2. The engine start control method according to claim 1, wherein the step 2) is specifically to control the first clutch clamping force corresponding to an original gear of the dual clutch transmission to decrease, and control the second clutch clamping force corresponding to a target gear of the dual clutch transmission to increase, and when the first clutch clamping force corresponding to the original gear is lower than a first preset threshold value and the second clutch clamping force corresponding to the target gear is greater than a second preset threshold value, the torque exchange of the dual clutch transmission is completed.

3. The engine start control method of a hybrid vehicle according to claim 1, wherein the step 3) includes:

4. The engine start control method according to claim 3, wherein the step 31) further comprises sending a control command of rotating speed synchronization to the engine clutch controller after the vehicle controller receives the rotating speed synchronization information sent by the dual clutch transmission controller.

5. The engine start control method of a hybrid vehicle according to claim 2, wherein the step 4) further includes:

step 42) when the rotating speed of the motor is lower than that of the target shaft, the double-clutch transmission controller sends a power source torque increasing request to a vehicle control unit to realize the active increase of the rotating speed of the motor;

when the rotating speed of the motor is higher than that of the target shaft, the double-clutch gearbox controller sends a power source torque reduction request to the whole vehicle controller to realize the active reduction of the rotating speed of the motor and complete the synchronization of the rotating speed of the motor and the rotating speed of the double-clutch gearbox.

6. The engine start control method according to claim 1, characterized by further comprising, before the step 1): step 01), the vehicle controller judges whether the engine needs to be started to be switched from the pure electric driving mode to the hybrid power driving mode according to the state of the vehicle power system;

7. The engine start control method according to claim 6, wherein the shift confirmation information of the dual clutch transmission controller includes a current gear of the dual clutch transmission, motor speed information, and accelerator pedal opening information.

8. The engine start control method according to claim 7, wherein the judgment rule of step 1) is information on an opening degree of the accelerator pedal, and includes:

when the opening degree of the accelerator pedal is higher than the preset threshold value of the pedal and the gear is to be shifted down, firstly synchronizing the rotating speed; when the opening degree of the accelerator pedal is lower than the preset pedal threshold value and the gear is to be shifted up, firstly carrying out rotation speed synchronization;

9. The engine start control method according to claim 3, wherein a motor output torque protection mechanism is further provided after the step 31), and comprises:

step 310), the engine clutch controller detects the current actual stroke of the engine clutch in real time, converts the actual stroke into a real-time torque in the starting process of the engine, and feeds back a real-time torque signal to the vehicle control unit;

10. A hybrid vehicle comprising an engine and an electric machine arranged in parallel, and a shift-controlled dual clutch transmission, characterized in that the engine start control method of the hybrid vehicle according to any one of claims 1 to 9 is employed when the dual clutch transmission is shifted and the engine and the electric machine are switched from purely electric to hybrid drive.