CN113548035A - Vehicle power system control method and device - Google Patents

Vehicle power system control method and device Download PDF

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Publication number
CN113548035A
CN113548035A CN202110969164.5A CN202110969164A CN113548035A CN 113548035 A CN113548035 A CN 113548035A CN 202110969164 A CN202110969164 A CN 202110969164A CN 113548035 A CN113548035 A CN 113548035A
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engine
motor
hybrid
speed
rotating speed
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CN113548035B (en
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刘辉
张伟
张万年
张勋
许浩欣
徐丽丽
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Beijing Institute of Technology BIT
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Beijing Institute of Technology BIT
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W20/00—Control systems specially adapted for hybrid vehicles
    • B60W20/40—Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/02—Conjoint control of vehicle sub-units of different type or different function including control of driveline clutches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/06—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of combustion engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W20/00—Control systems specially adapted for hybrid vehicles
    • B60W20/20—Control strategies involving selection of hybrid configuration, e.g. selection between series or parallel configuration
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/62—Hybrid vehicles

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Automation & Control Theory (AREA)
  • Hybrid Electric Vehicles (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention provides a control method and a device of a vehicle power system, which are applied to the technical field of vehicles. The control method provided by the invention can complete the starting control of the engine under the condition that the pure electric drive mode needs to be switched to the hybrid drive mode, so that the engine is switched to the hybrid drive mode, and the actual application requirements are met.

Description

Vehicle power system control method and device
Technical Field
The invention belongs to the technical field of vehicles, and particularly relates to a vehicle power system control method and device.
Background
With the development of new energy automobile technology, the new energy automobile adopting the hybrid power system is widely applied because the advantages of the diesel locomotive and the pure electric vehicle can be fully exerted, and the purposes of energy saving and environmental protection are achieved under the condition of taking the endurance mileage into consideration. Fig. 1 is a schematic structural diagram of a new energy vehicle employing a hybrid power system, in which a first motor and a second motor driven by a power battery form an electric drive system, an engine serves as an internal combustion engine power system, the two realize coupling of drive power through a coupling mechanism, and finally the vehicle is driven to run through a main reducer.
Further, fig. 2 shows a basic structure of a hybrid system in the related art, which is mainly composed of an engine, a first electric machine, a second electric machine, and a coupling mechanism, wherein the coupling mechanism specifically includes a front transmission mechanism, three planetary gear rows PG1, PG2, and PG3, a main clutch CL0, a sub clutch CL1, and a brake BK. Ring gear 1 in PG1 is connected to a first motor, sun gear 2 in PG2 is connected to a second motor, planet carrier 2 in PG2 is connected to a front transmission mechanism, main clutch CL0 is connected to the engine and the front transmission mechanism, clutch CL1 is connected to planet carrier 1 in PG1 and planet carrier 3 in PG3, brake BK is used for locking ring gear 3 of PG3, planet carrier 3 of PG3 is connected to an output shaft of a coupling mechanism, and the output shaft transmits power to driving wheels through a main speed reducer so as to drive the vehicle to run.
As can be seen from fig. 1 and 2, a vehicle using a hybrid power system has multiple driving modes, and switching between different driving modes is involved in a driving process, and in various switching processes, switching from a pure electric driving mode to a hybrid driving mode is the most complicated and important switching process, and smoothness of the switching process directly impresses driving feeling of a driver, so how to provide a control method for a power system to realize smooth switching from the pure electric driving mode to the hybrid driving mode becomes one of technical problems to be solved by those skilled in the art.
Disclosure of Invention
In view of this, the present invention provides a method and a device for controlling a vehicle powertrain, which implement smooth switching from a pure electric drive mode to a hybrid drive mode, and meet the actual application requirements, and the specific scheme is as follows:
in a first aspect, the present invention provides a vehicle powertrain control method applied to a hybrid powertrain including an engine, a first electric machine, and a second electric machine, the method comprising:
under the condition that the hybrid power system is in a pure electric driving mode, judging whether a hybrid driving mode needs to be switched or not;
if the hybrid driving mode needs to be switched, controlling a main clutch in the hybrid power system to be engaged;
controlling the first motor and the second motor to drag the engine, and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed;
increasing the rotation speed of the engine to a target rotation speed, and controlling the output torques of the first motor and the second motor according to the rotation speed of the engine so as to enable the deviation of the output torque of the hybrid power system to be within a preset range;
wherein the target rotation speed is a rotation speed at which the loss of the engine is in a fuel economy region.
Optionally, the controlling engagement of a main clutch in the hybrid system includes:
adjusting the rotation speed of a driven end of a main clutch in the hybrid power system;
controlling the main clutch to be half-engaged when the speed difference between the driven end rotating speed and the driving end rotating speed of the main clutch is smaller than a first rotating speed threshold value;
controlling the main clutch to be completely engaged when the speed difference between the driven end rotating speed and the driving end rotating speed is smaller than a second rotating speed threshold value;
wherein the second rotational speed threshold is less than the first rotational speed threshold.
Optionally, the adjusting the rotation speed of the driven end of the main clutch in the hybrid power system includes:
acquiring a first required torque, a first angular speed of an output end of a coupling mechanism in the hybrid power system and a current angular speed of the first motor;
determining a first target angular velocity of the first motor according to the first angular velocity of the output end;
determining a first target torque of the first motor according to the current angular velocity of the first motor and the first target angular velocity;
determining a first target torque of the second electric machine according to the first required torque and a first target torque of the first electric machine;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to adjust the driven end rotating speed of a main clutch in the hybrid power system.
Optionally, the controlling the first motor and the second motor to drive the engine includes:
acquiring an input end angular velocity, an input end reference angular velocity, an output end second angular velocity and an output end reference angular velocity of a coupling mechanism in the hybrid power system;
inputting the input end angular velocity, the input end reference angular velocity, the output end second angular velocity and the output end reference angular velocity into a preset model predictive controller respectively to obtain a second target torque of the first motor and a second target torque of the second motor;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to drag the engine.
Optionally, the controlling the output torques of the first motor and the second motor according to the rotation speed of the engine includes:
acquiring a current rotating speed and a second required torque of the engine;
determining the current torque of the engine according to the current rotating speed of the engine and the target rotating speed;
determining a third target torque of the first electric machine according to the current torque of the engine;
determining a third target torque of the second electric machine according to a third target torque of the first electric machine and the second required torque;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torques.
Optionally, the determining whether to switch to the hybrid driving mode includes:
acquiring target parameters representing the running state of the vehicle;
and judging whether to switch to a hybrid driving mode or not according to the target parameter.
Optionally, the target parameters include a current vehicle speed, a current SOC value of the power battery, and a current required power.
Optionally, the determining whether to switch to the hybrid driving mode according to the target parameter includes:
and if the current vehicle speed is greater than the highest vehicle speed of the pure electric drive mode, or the current SOC value is smaller than a preset SOC threshold value, or the current required power is greater than the maximum power of the pure electric drive mode, judging that the hybrid drive mode needs to be switched.
In a second aspect, the present invention provides a vehicle powertrain control apparatus applied to a hybrid powertrain including an engine, a first motor, and a second motor, the apparatus comprising:
the judging unit is used for judging whether the hybrid power system needs to be switched to a hybrid driving mode or not under the condition that the hybrid power system is in a pure electric driving mode;
a first control unit for controlling engagement of a main clutch in the hybrid system if switching to the hybrid drive mode is required;
the second control unit is used for controlling the first motor and the second motor to drag the engine and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed;
a third control unit configured to increase a rotation speed of the engine to a target rotation speed and control output torques of the first and second motors according to the rotation speed of the engine so that a deviation of the output torque of the hybrid system is within a preset range;
wherein the target rotation speed is a rotation speed at which the loss of the engine is in a fuel economy region.
Optionally, the first control unit, when being used to control engagement of a main clutch in the hybrid system, specifically includes:
adjusting the rotation speed of a driven end of a main clutch in the hybrid power system;
controlling the main clutch to be half-engaged when the speed difference between the driven end rotating speed and the driving end rotating speed of the main clutch is smaller than a first rotating speed threshold value;
controlling the main clutch to be completely engaged when the speed difference between the driven end rotating speed and the driving end rotating speed is smaller than a second rotating speed threshold value;
wherein the second rotational speed threshold is less than the first rotational speed threshold.
The method for controlling the vehicle power system is applied to a hybrid power system comprising an engine, a first motor and a second motor, and comprises the steps of controlling a main clutch in the hybrid power system to be engaged under the condition that the pure electric drive mode needs to be switched to the hybrid drive mode, then controlling the first motor and the second motor to drag the engine, controlling the engine to ignite and start under the condition that the rotating speed of the engine reaches the preset ignition rotating speed, actively controlling the engine after the engine is started, increasing the rotating speed of the engine to the target rotating speed which enables the loss of the engine to be in a fuel economy area, and controlling the output torques of the first motor and the second motor according to the rotating speed of the engine so as to enable the deviation of the output torque of the hybrid power system to be in the preset range. The control method provided by the invention can complete the starting control of the engine under the condition that the pure electric drive mode needs to be switched to the hybrid drive mode, so that the engine is switched to the hybrid drive mode, and the actual application requirements are met.
Furthermore, in the process of switching the driving modes, the output torque of the driving motor is adjusted according to the rotating speed of the engine, the influence of the rotating speed of the engine on the output torque between the first motor and the second motor is considered, the deviation of the output torque of the hybrid power system is ensured to be within a preset range, the torque fluctuation caused by the fact that the torque of the engine is connected into the power system after the engine is started can be effectively reduced, the longitudinal impact of the whole vehicle is avoided, and the driving feeling is improved.
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 introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a new energy vehicle employing a hybrid power system in the prior art;
FIG. 2 is a schematic block diagram of a prior art hybrid powertrain;
FIG. 3 is a flow chart of a method for controlling a powertrain of a vehicle in accordance with an embodiment of the present invention;
FIG. 4 is a control block diagram of a master clutch engagement process provided by an embodiment of the present invention;
FIG. 5 is a control block diagram of a process for motoring the engine back provided by an embodiment of the present invention;
FIG. 6 is a control block diagram of a process for adjusting output torque of an electric machine based on engine speed, provided by an embodiment of the present invention;
fig. 7 is a block diagram of a vehicle powertrain control device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In combination with the foregoing, a new energy vehicle adopting a hybrid system has a plurality of driving modes, which roughly include a pure electric driving mode, a mechanical driving mode, a driving power generation mode, a parking power generation mode, and a hybrid driving mode, wherein the mechanical driving mode refers to a mode in which the vehicle is driven by an engine to run. In the actual use process of the new energy vehicle, the vehicle can be switched among different driving modes according to different specific vehicle conditions and different driving working conditions, so that the performance of the vehicle is fully exerted. The control method provided by the invention is mainly used for solving the problems existing in the switching process from the pure electric driving mode to the hybrid driving mode and ensuring the smoothness of the switching process.
Based on the above, the embodiment of the invention provides a control method for a vehicle power system, which may be applied to a controller of the vehicle power system, or may also be applied to a vehicle controller, or of course, may also be applied to a controller that is arranged on a vehicle and is capable of acquiring corresponding data and executing a preset control program.
Optionally, referring to fig. 3, fig. 3 is a flowchart of a vehicle powertrain control method according to an embodiment of the present invention, where the flowchart of the vehicle powertrain control method according to the embodiment may include:
s100, judging whether the hybrid driving mode needs to be switched or not, and if so, executing S110.
As described above, the embodiment of the present invention mainly provides a control method for switching a power system from an electric drive mode to a hybrid drive mode, and therefore, the precondition for executing this step is that the hybrid power system is in the electric drive mode. If it is necessary to switch to the hybrid driving mode, S110 is performed, and conversely, if it is not necessary to switch to the hybrid driving mode, the current driving state of the vehicle may be maintained.
Optionally, in the process of determining whether to switch to the hybrid driving mode, first, target parameters representing the vehicle operating state, such as the current vehicle speed of the vehicle, the current SOC value of the power battery, the current required power, and the like, need to be obtained, and then, whether to switch to the hybrid driving mode is determined according to the target parameters.
Specifically, if the current vehicle speed is greater than the highest vehicle speed of the pure electric drive mode, or the current SOC value is smaller than a preset SOC threshold value, or the current required power is greater than the maximum power of the pure electric drive mode, it is determined that the hybrid drive mode needs to be switched to.
It should be noted that, for setting the preset SOC threshold, the setting may be based on specific parameters of the vehicle and the power battery, and the specific value of the preset SOC threshold is not limited in the present invention. The acquisition of the current required power can be calculated based on a driver calculation model in the prior art, and is not expanded here.
And S110, controlling the engagement of a main clutch in the hybrid power system.
If it is determined that a mode switch is required, the master clutch engagement in the hybrid system is first controlled.
Specifically, the first motor in the structural schematic diagram shown in fig. 2 is used to eliminate the speed difference between the driving end and the driven end of the main clutch, so as to reduce the idle speed at the input end of the coupling mechanism and ensure that the main clutch is combined at a low speed difference.
Firstly, the rotation speed of a driven end of a main clutch in a hybrid power system is regulated, when the speed difference between the rotation speed of the driven end and the rotation speed of a driving end of the main clutch is smaller than a first rotation speed threshold value, the main clutch is controlled to be half engaged, and then, when the speed difference between the rotation speed of the driven end and the rotation speed of the driving end is smaller than a second rotation speed threshold value, the main clutch is controlled to be completely engaged.
It should be noted that, according to the basic operation principle of the clutch, during the engagement process of the clutch, the rotation speed difference between the driving end and the driven end of the clutch is gradually reduced until the rotation speeds are consistent, and the engagement is completed, so that the second rotation speed threshold mentioned in this embodiment is smaller than the first rotation speed threshold, for example, in practical application, the first rotation speed threshold is 50r/min, and the second rotation speed threshold may be 0 r/min.
Further, according to the angular velocity coupling relation, the angular velocity at the input end of the coupling mechanism is made zero, and the first target angular velocity of the first motor in this step can be obtained:
Figure BDA0003224994260000071
wherein,
Figure BDA0003224994260000072
representing a first target angular velocity of the first motor;
ωorepresenting a first angular velocity at an output of the coupling mechanism;
k1、k2、k3characteristic parameters of the planetary gear mechanisms PG1, PG2, and PG3, that is, the ratios of the number of teeth of the ring gear to the number of teeth of the sun gear in the configuration of the hybrid system shown in fig. 2 are respectively shown.
Based on the above, it can be seen that in practical applications, k is the number k for certain hybrid systems1、k2、k3It is known that, therefore, a first angular velocity at the output end of a coupling mechanism in a hybrid system needs to be obtained, and a first target angular velocity of a first electric machine can be determined according to the first angular velocity at the output end according to formula (1).
The torque of the first electric machine is controlled by the PID controller on the basis of the first target angular velocity, because a change in the torque of the first electric machine affects the output torque of the coupling mechanism due to the presence of the torque coupling relation (2).
Figure BDA0003224994260000081
Wherein, ToRepresenting the output torque of the coupling mechanism;
TArepresenting a torque of the first electric machine;
TBrepresenting the torque of the second electrical machine.
It can be seen that the torques of the first and second electric machines together affect the output torque of the coupling mechanism and should be taken into account in the control of the first and second electric machines. In the case where the first target angular velocity of the first electric machine has been obtained through the foregoing steps, it is further necessary to obtain a first required torque, which is calculated by a driver model in the prior art based on parameters such as an accelerator pedal opening degree, and a current angular velocity of the first electric machine, and details of this are not described here.
And then, determining a first target torque of the first motor according to the current angular speed of the first motor and the first target angular speed obtained by the calculation, and simultaneously determining a first target torque of the second motor according to the first required torque and the first target torque of the first motor, so that after the target torques of the first motor and the second motor are obtained, the first motor and the second motor can be respectively controlled to operate according to the corresponding target torques, the rotating speed of a driven end of a main clutch in the hybrid power system is adjusted, and the engagement of the main clutch is finally realized.
The calculation process can be seen in the control block diagram of the main clutch engagement process shown in fig. 4. In the pure electric driving mode, the main clutch is separated, the auxiliary clutch is separated, the brake is engaged, the engine and the first motor are in a non-operating state, and the second motor is used for driving the vehicle to run independently. At this time, the input end of the coupling mechanism is a port connected with the second motor, and the output end of the coupling mechanism is connected with the output shaft to drive the wheels through the speed reducer.
In the hybrid driving mode, the main clutch is combined, the auxiliary clutch is separated, the brake is combined, the engine is in a working state, the first motor is in a power generation state, the second motor is in an electric state, and the engine and the second motor jointly drive the vehicle to run. At this time, the input end of the coupling mechanism is respectively a port connected with the second motor and the front transmission mechanism, and the output end of the coupling mechanism is respectively a port connected with the output shaft and the first motor.
And S120, controlling the first motor and the second motor to drag the engine, and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed.
After the main clutch is engaged, the engine is back-towed using the first and second electric machines to increase the engine speed to the preset ignition speed, according to the control scheme shown in fig. 5.
As shown in fig. 5, in a specific implementation, an input end angular velocity, an input end reference angular velocity, an output end second angular velocity, and an output end reference angular velocity of a coupling mechanism in a hybrid system need to be obtained, then the obtained input end angular velocity, the obtained input end reference angular velocity, the obtained output end second angular velocity, and the obtained output end reference angular velocity are respectively input to a preset model prediction controller, and finally a second target torque of a first motor and a second target torque of a second motor are obtained, and the first motor and the second motor are respectively controlled to operate according to the corresponding target torques, so as to drag an engine to reach a preset ignition rotational speed, and then the engine is controlled to ignite and start.
The preset model predictive controller can be implemented based on the prior art, and the specific content and implementation manner of the controller are not limited in the invention.
In the process of controlling the first motor and the second motor to drive the engine, the stability of the output torque of the coupling mechanism can be measured according to the following formula:
Figure BDA0003224994260000091
wherein j represents the impact degree of the whole vehicle;
r represents a wheel radius;
irrepresenting the final drive ratio;
ω1representing a second angular velocity at the output of the coupling mechanism.
It should be noted that, during the process of dragging the engine by the first motor and the second motor, the output torque fluctuates due to the variation of the engine torque. Before ignition, engine torque is expressed as a drag torque and can change along with the change of the crank angle and the rotating speed of the engine; after ignition, the engine torque is expressed as a driving torque. In the stage that the motor reversely drags the engine, before ignition, the torque of the engine is expressed as resistance torque, at the moment, the torque output by the first motor is changed from the negative torque in the original power generation state to the positive torque in the electric state, after ignition, the engine outputs driving torque, and the first motor is changed into the power generation state again to output the negative torque outwards; the second motor torque also adjusts its output torque value in order to maintain the output torque stable due to the change of the first motor torque.
And S130, increasing the rotating speed of the engine to a target rotating speed, and controlling the output torques of the first motor and the second motor according to the rotating speed of the engine so as to enable the deviation of the output torque of the hybrid power system to be in a preset range.
After the engine is ignited and started, namely, the engine enters the stage of active speed regulation, the target rotating speed mentioned in the embodiment is the rotating speed which enables the loss of the engine to be in a fuel economy area. For a certain hybrid power system, the fuel economy zone of the engine is known, the corresponding target rotating speed can be set based on the fuel economy zone, and the specific value of the target rotating speed is not limited by the invention.
In the process of controlling the output torques of the first motor and the second motor in accordance with the rotation speed of the engine so that the deviation of the output torques of the hybrid system is within the preset range, it can be realized in conjunction with the control block diagram shown in fig. 6.
Specifically, after the current rotation speed and the second required torque of the engine are obtained, the current torque of the engine is determined according to the current rotation speed and the target rotation speed of the engine, then the third target torque of the first motor is determined according to the current torque of the engine, the third target torque of the second motor is determined according to the third target torque of the first motor and the second required torque, and finally the first motor and the second motor are respectively controlled to operate according to the corresponding target torques.
In summary, the control method provided by the invention can complete the starting control of the engine when the pure electric drive mode needs to be switched to the hybrid drive mode, so as to switch to the hybrid drive mode, thereby meeting the actual application requirements.
Furthermore, in the process of switching the driving modes, the output torque of the driving motor is adjusted according to the rotating speed of the engine, the influence of the rotating speed of the engine on the output torque between the first motor and the second motor is considered, the deviation of the output torque of the hybrid power system is ensured to be within a preset range, the torque fluctuation caused by the fact that the torque of the engine is connected into the power system after the engine is started can be effectively reduced, the longitudinal impact of the whole vehicle is avoided, and the driving feeling is improved.
The following describes a vehicle powertrain control apparatus according to an embodiment of the present invention, where the vehicle powertrain control apparatus described below may be regarded as a functional module architecture that needs to be installed in a central device to implement the vehicle powertrain control method according to the embodiment of the present invention; the following description may be cross-referenced with the above.
Referring to fig. 7, fig. 7 is a block diagram of a vehicle powertrain control device according to an embodiment of the present invention, which is applied to a hybrid powertrain including an engine, a first motor, and a second motor, and includes:
the hybrid power system comprises a judging unit 10, a control unit and a control unit, wherein the judging unit is used for judging whether to switch to a hybrid driving mode or not under the condition that the hybrid power system is in a pure electric driving mode;
a first control unit 20 for controlling engagement of a main clutch in the hybrid system if a shift to a hybrid driving mode is required;
the second control unit 30 is used for controlling the first motor and the second motor to drag the engine and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed;
a third control unit 40 for raising the rotational speed of the engine to a target rotational speed and controlling the output torques of the first and second motors according to the rotational speed of the engine so that a deviation of the output torques of the hybrid system is within a preset range;
wherein the target rotation speed is a rotation speed at which the loss of the engine is in a fuel economy region.
Optionally, the first control unit 20, when controlling the engagement of the main clutch in the hybrid system, specifically includes:
adjusting the rotation speed of a driven end of a main clutch in a hybrid power system;
when the speed difference between the rotating speed of the driven end and the rotating speed of the driving end of the main clutch is smaller than a first rotating speed threshold value, controlling the main clutch to be half-engaged;
when the speed difference between the rotating speed of the driven end and the rotating speed of the driving end is smaller than a second rotating speed threshold value, the main clutch is controlled to be completely engaged;
wherein the second rotational speed threshold is less than the first rotational speed threshold.
Optionally, the first control unit 20, when being configured to adjust the driven end rotation speed of the main clutch in the hybrid system, specifically includes:
acquiring a first required torque, a first angular speed of an output end of a coupling mechanism in a hybrid power system and a current angular speed of a first motor;
determining a first target angular speed of the first motor according to the first angular speed of the output end;
determining a first target torque of the first motor according to the current angular speed and the first target angular speed of the first motor;
determining a first target torque of the second electric machine according to the first required torque and the first target torque of the first electric machine;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to adjust the rotation speed of a driven end of a main clutch in the hybrid power system.
The second control unit 30 is configured to control the first motor and the second motor to drive the engine, and specifically includes:
acquiring an input end angular velocity, an input end reference angular velocity, an output end second angular velocity and an output end reference angular velocity of a coupling mechanism in a hybrid power system;
inputting the input end angular velocity, the input end reference angular velocity, the output end second angular velocity and the output end reference angular velocity into a preset model prediction controller respectively to obtain a second target torque of the first motor and a second target torque of the second motor;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to drag the engine.
Optionally, the third control unit 40 is configured to control the output torques of the first electric machine and the second electric machine according to the rotation speed of the engine, and specifically includes:
acquiring the current rotating speed and the second required torque of the engine;
determining the current torque of the engine according to the current rotating speed and the target rotating speed of the engine;
determining a third target torque of the first motor according to the current torque of the engine;
determining a third target torque of the second electric machine according to the third target torque of the first electric machine and the second required torque;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque.
The determining unit 10 is configured to determine whether to switch to the hybrid driving mode, and specifically includes:
acquiring target parameters representing the running state of the vehicle;
and judging whether to switch to the hybrid driving mode or not according to the target parameters.
Optionally, the target parameters include a current vehicle speed, a current SOC value of the power battery, and a current required power.
The determining unit 10 is configured to determine whether to switch to the hybrid driving mode according to the target parameter, and specifically includes:
and if the current vehicle speed is greater than the highest vehicle speed of the pure electric drive mode, or the current SOC value is smaller than a preset SOC threshold value, or the current required power is greater than the maximum power of the pure electric drive mode, judging that the hybrid drive mode needs to be switched.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
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 (10)

1. A vehicle powertrain control method applied to a hybrid powertrain including an engine, a first motor, and a second motor, the method comprising:
under the condition that the hybrid power system is in a pure electric driving mode, judging whether a hybrid driving mode needs to be switched or not;
if the hybrid driving mode needs to be switched, controlling a main clutch in the hybrid power system to be engaged;
controlling the first motor and the second motor to drag the engine, and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed;
increasing the rotation speed of the engine to a target rotation speed, and controlling the output torques of the first motor and the second motor according to the rotation speed of the engine so as to enable the deviation of the output torque of the hybrid power system to be within a preset range;
wherein the target rotation speed is a rotation speed at which the loss of the engine is in a fuel economy region.
2. The vehicle powertrain control method of claim 1, wherein the controlling engagement of a main clutch in the hybrid powertrain includes:
adjusting the rotation speed of a driven end of a main clutch in the hybrid power system;
controlling the main clutch to be half-engaged when the speed difference between the driven end rotating speed and the driving end rotating speed of the main clutch is smaller than a first rotating speed threshold value;
controlling the main clutch to be completely engaged when the speed difference between the driven end rotating speed and the driving end rotating speed is smaller than a second rotating speed threshold value;
wherein the second rotational speed threshold is less than the first rotational speed threshold.
3. The vehicle powertrain control method of claim 2, wherein the adjusting the driven-end rotational speed of a master clutch in the hybrid powertrain system includes:
acquiring a first required torque, a first angular speed of an output end of a coupling mechanism in the hybrid power system and a current angular speed of the first motor;
determining a first target angular velocity of the first motor according to the first angular velocity of the output end;
determining a first target torque of the first motor according to the current angular velocity of the first motor and the first target angular velocity;
determining a first target torque of the second electric machine according to the first required torque and a first target torque of the first electric machine;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to adjust the driven end rotating speed of a main clutch in the hybrid power system.
4. The vehicle powertrain control method of claim 1, wherein the controlling the first and second electric machines to tow the engine comprises:
acquiring an input end angular velocity, an input end reference angular velocity, an output end second angular velocity and an output end reference angular velocity of a coupling mechanism in the hybrid power system;
inputting the input end angular velocity, the input end reference angular velocity, the output end second angular velocity and the output end reference angular velocity into a preset model predictive controller respectively to obtain a second target torque of the first motor and a second target torque of the second motor;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torque so as to drag the engine.
5. The vehicle powertrain control method of claim 1, wherein the controlling the output torques of the first and second electric machines according to the rotational speed of the engine includes:
acquiring a current rotating speed and a second required torque of the engine;
determining the current torque of the engine according to the current rotating speed of the engine and the target rotating speed;
determining a third target torque of the first electric machine according to the current torque of the engine;
determining a third target torque of the second electric machine according to a third target torque of the first electric machine and the second required torque;
and respectively controlling the first motor and the second motor to operate according to the corresponding target torques.
6. The vehicle powertrain control method of any one of claims 1-5, wherein the determining whether a switch to a hybrid drive mode is required includes:
acquiring target parameters representing the running state of the vehicle;
and judging whether to switch to a hybrid driving mode or not according to the target parameter.
7. The vehicle powertrain control method of claim 6, wherein the target parameters include a current vehicle speed, a current SOC value of a power battery, and a current required power.
8. The vehicle powertrain control method of claim 7, wherein the determining whether a switch to a hybrid drive mode is required based on the target parameter includes:
and if the current vehicle speed is greater than the highest vehicle speed of the pure electric drive mode, or the current SOC value is smaller than a preset SOC threshold value, or the current required power is greater than the maximum power of the pure electric drive mode, judging that the hybrid drive mode needs to be switched.
9. A vehicular power system control apparatus, characterized by being applied to a hybrid power system including an engine, a first electric machine, and a second electric machine, the apparatus comprising:
the judging unit is used for judging whether the hybrid power system needs to be switched to a hybrid driving mode or not under the condition that the hybrid power system is in a pure electric driving mode;
a first control unit for controlling engagement of a main clutch in the hybrid system if switching to the hybrid drive mode is required;
the second control unit is used for controlling the first motor and the second motor to drag the engine and controlling the engine to ignite and start when the rotating speed of the engine reaches a preset ignition rotating speed;
a third control unit configured to increase a rotation speed of the engine to a target rotation speed and control output torques of the first and second motors according to the rotation speed of the engine so that a deviation of the output torque of the hybrid system is within a preset range;
wherein the target rotation speed is a rotation speed at which the loss of the engine is in a fuel economy region.
10. The vehicle powertrain control device according to claim 9, wherein the first control unit is configured to control engagement of a main clutch in the hybrid powertrain, and specifically includes:
adjusting the rotation speed of a driven end of a main clutch in the hybrid power system;
controlling the main clutch to be half-engaged when the speed difference between the driven end rotating speed and the driving end rotating speed of the main clutch is smaller than a first rotating speed threshold value;
controlling the main clutch to be completely engaged when the speed difference between the driven end rotating speed and the driving end rotating speed is smaller than a second rotating speed threshold value;
wherein the second rotational speed threshold is less than the first rotational speed threshold.
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