CN115257750A

CN115257750A - Plug-in hybrid vehicle starting control method and system

Info

Publication number: CN115257750A
Application number: CN202210884517.6A
Authority: CN
Inventors: 韦永恒
Original assignee: Lianlu Intelligent Transportation Technology Shanghai Co ltd
Current assignee: Lianlu Intelligent Transportation Technology Shanghai Co ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2022-11-01

Abstract

The invention provides a starting control method and a starting control system for a plug-in hybrid vehicle, which comprise the following steps: step S1: acquiring running conditions and vehicle information, determining the combination oil pressure of a wet clutch, and determining the running required torque; step S2: judging the driving intention and the type, controlling the torque change of power sources of the engine and the driving motor based on the maximum torque change rate limited by the impact degree, and enabling the torque fluctuation of the engine and the driving motor from the speed change mechanism to the wheel end to be within a preset range, thereby carrying out the torque distribution required by the whole vehicle; and step S3: performing power source torque coordination control based on PID feedback control; step S4; and based on the operation intention of the driver, performing coordinated control on the vehicle starting dynamic process through the operation intention controller of the driver and the oil pressure controller of the wet clutch. The invention can improve the smoothness and the comfort of drivers and passengers in the starting dynamic process of the plug-in hybrid electric vehicle while meeting the requirements of the dynamic property and the economical efficiency of the plug-in hybrid electric vehicle.

Description

Plug-in hybrid vehicle starting control method and system

Technical Field

The invention relates to the technical field of vehicle starting dynamic process control, in particular to a plug-in hybrid vehicle starting control method and system, and more particularly to a plug-in hybrid vehicle dual-power source combined starting dynamic process coordination control method and system.

Background

In the dynamic starting process, different vehicle running conditions can be formed by random combination of factors such as the load size of the whole vehicle, the gradient type and size, the SOC state and the like, and the operation judgment of a driver can be influenced to a certain extent.

The driver expresses his driving will mainly by the depth and speed of pedaling, and reflects the degree of opening of the pedal and the change of the change rate of the pedal opening. How to combine different running conditions with various starting types of hybrid electric vehicles more effectively is very important.

When the torque demand of the whole vehicle is large, the upper limit of the transferable torque of the double-clutch input shaft and the service life of a clutch plate are considered, the engine is driven by utilizing the advantage of quick response of the driving motor, the engine is helped to span a low rotating speed area, and the ignition is directly carried out near the idle rotating speed. The significance of effectively solving the problems of serious oil consumption and emission in a low-rotating-speed area of an engine, upper limit of transmission torque of a clutch, service life and the like is obvious.

Patent document CN112677958A (application number: CN 202110025858.3) discloses a vehicle starting control method, system and vehicle, wherein when a starting requirement of the vehicle is detected, a power control unit PCU of the whole vehicle controls power source torque and clutch torque slope, clutch reference torque and clutch offset torque jointly act, clutch target transmission torque is finely adjusted in real time according to actual rotating speed of the power source, and rotating speed of a power source end is guided to rise to a target rotating speed along with guiding rotating speed until the rotating speed of the power source and rotating speed of an input shaft of a gearbox are synchronous. However, the influence of different starting working conditions on the starting judgment of a driver is formed by random combination of factors such as the load size, the gradient type and the size of the whole vehicle and the SOC state is not considered in the patent.

Patent document CN110615000A (application number: CN 201910966436.9) discloses a working control mode of a plug-in hybrid electric vehicle, which selects a starting mode condition according to a control module, where the current mode switch of the plug-in hybrid electric vehicle is determined, the starting mode includes a first starting condition and a second starting condition, and two starting condition determination conditions are provided. The mode switch of the plug-in hybrid electric vehicle comprises two driving modes, namely a pure electric driving economic mode and a hybrid driving economic mode, and whether the driving speed information of the hybrid electric vehicle meets the starting speed range and the low-speed cruising range of the hybrid electric vehicle is judged according to the acquired driving speed information, wherein the specific working modes comprise a rear motor driving working mode, a driving charging working mode and an engine independent working mode; and further, judging whether the running vehicle speed information of the hybrid power system meets the high-speed cruising range of the hybrid power system, wherein the specific working mode comprises a motor full-drive working mode and a running drive working mode. However, in the starting dynamic process, the influence of different running working conditions on the operation judgment of a driver is formed by the random combination of factors such as the load size, the gradient type and the size of the whole vehicle, the SOC state and the like.

Disclosure of Invention

The invention aims to provide a starting control method and a starting control system for a plug-in hybrid vehicle, aiming at the defects in the prior art.

According to the invention, the plug-in hybrid vehicle starting control method comprises the following steps:

step S1: acquiring running conditions and vehicle information, determining the combination oil pressure of a wet clutch, and determining the required running torque;

step S2: judging the driving intention and the type, controlling the torque change of power sources of the engine and the driving motor based on the maximum torque change rate limited by the impact degree, enabling the torque fluctuation of the engine and the driving motor from the speed change mechanism to the wheel end to be within a preset range, and distributing the required torque of the whole vehicle;

and step S3: performing power source torque coordination control based on PID feedback control;

step S4; and based on the operation intention of the driver, performing coordinated control on the vehicle starting dynamic process through the operation intention controller of the driver and the oil pressure controller of the wet clutch.

Preferably, the driving condition and the vehicle information are acquired, wherein the driving condition and the vehicle information comprise the operation intention of a driver, the power demand of the whole vehicle and the SOC state of a battery pack;

whether a starting condition is met or not is judged by reading the vehicle speed, the pedal opening degree and the change rate thereof, the current SOC and the current running mode of the vehicle, the combination oil pressure of a wet clutch is determined, the running required torque is determined, the actual torque is controlled and output by a driving motor controller and an engine controller, and a dynamic equation is expressed as follows:

in the formula: t is _dtar Is power source torque; t is _mtar 、T _etar The torque required by the next target driving motor and the engine respectively; t is _e 、T _m Actual torques of the current engine and the current driving motor are respectively; x and Y are torque change rates of the engine and the driving motor respectively.

Preferably, in the step S3:

the target torque of the engine is converted into the opening degree of an accelerator pedal through a PID algorithm, the maximum impact degree of the whole vehicle is limited as a control target, increment compensation is carried out on the control target, and the output torque of the control target is directly controlled through a torque command.

Preferably, in the step S4:

the driver operation intention controller: the method comprises the steps of taking the opening degree and the change rate of an accelerator pedal as input, taking the operation intention of a driver as output, enabling the operation intention of the driver to correspond to different vehicle running torque requirements through the opening degree and the change rate of the accelerator pedal, and formulating a fuzzy control rule according to input of a driver operation intention fuzzy controller and a fuzzy subset membership function of an output variable to obtain a driver operation intention fuzzy control curved surface.

Preferably, in the step S4:

the wet clutch oil pressure controller: according to the operation intention of a driver and the running condition of a vehicle, a double-layer fuzzy control strategy is adopted, in a second-layer fuzzy controller, the operation intention of the driver, the rotating speed of an engine and the difference between the rotating speed of a main engine and the rotating speed of a slave engine of a clutch are used as input, the combination or separation of the oil pressure of the clutch is used as output, and a fuzzy control rule is established according to the combination of the membership function of a fuzzy subset of input and output variables of the fuzzy controller combined with the change rate of the oil pressure, so that a fuzzy control curved surface combined with the change rate of the oil pressure is obtained.

According to the invention, the plug-in hybrid vehicle starting control system comprises:

a module M1: acquiring running conditions and vehicle information, determining the combination oil pressure of a wet clutch, and determining the running required torque;

a module M2: judging the driving intention and the type, controlling the torque change of power sources of the engine and the driving motor based on the maximum torque change rate limited by the impact degree, enabling the torque fluctuation of the engine and the driving motor from the speed change mechanism to the wheel end to be within a preset range, and distributing the required torque of the whole vehicle;

a module M3: performing power source torque coordination control based on PID feedback control;

a module M4; and based on the operation intention of the driver, performing coordinated control on the vehicle starting dynamic process through the operation intention controller of the driver and the oil pressure controller of the wet clutch.

whether a starting condition is met or not is judged by reading the vehicle speed, the pedal opening and the change rate thereof, the current SOC and the current running mode of the vehicle, the combination oil pressure of a wet clutch is determined, the running required torque is determined, the actual torque is controlled and output by a driving motor controller and an engine controller, and the dynamic equation is expressed as:

in the formula: t is _dtar Is power source torque; t is _mtar 、T _etar The torque required by the next target driving motor and the engine respectively; t is a unit of _e 、T _m Actual torques of the current engine and the current driving motor are respectively; x and Y are respectively the torque change rates of the engine and the driving motor.

Preferably, in said module M3:

Preferably, in said module M4:

the driver operation intention controller: the method comprises the steps of taking the opening degree and the change rate of an accelerator pedal as input, taking the operation intention of a driver as output, enabling the operation intention of the driver to correspond to different vehicle running torque requirements through the opening degree and the change rate of the accelerator pedal, and formulating a fuzzy control rule according to the input of a driver operation intention fuzzy controller and a fuzzy subset membership function of an output variable to obtain a driver operation intention fuzzy control curved surface.

Preferably, in said module M4:

Compared with the prior art, the invention has the following beneficial effects:

1. the invention considers that in the dynamic starting process, the random combination of factors such as load size, gradient type and size of the whole vehicle, SOC state and the like can form different driving working conditions to influence the operation judgment of a driver, the factors are designed into the vehicle driving torque demand condition, when the whole vehicle torque demand is larger, the upper limit of transferable torque of a double-clutch input shaft and the service life of a clutch plate are considered, the engine is driven by utilizing the advantage of quick response of a driving motor, the engine is helped to span a low-rotating-speed area, and the ignition is directly carried out from the vicinity of an idle rotating speed, so that the problems of serious oil consumption and emission of the low-rotating-speed area of the engine, the upper limit of the transferred torque of the clutch, the service life and the like can be effectively solved while the current whole vehicle state and the driver demand can be accurately detected;

2. the invention can improve the smoothness and the comfort of drivers and passengers in the starting dynamic process of the plug-in hybrid electric vehicle while meeting the requirements of the dynamic property and the economical efficiency of the plug-in hybrid electric vehicle.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a logic diagram of control of a dual-power source combined starting process of a plug-in hybrid vehicle;

FIG. 2 is a driver operational intention recognition fuzzy controller;

FIG. 3 is a wet clutch engagement oil pressure rate of change fuzzy controller.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1:

as shown in fig. 1 to 3, the start control method for a plug-in hybrid vehicle according to the present invention includes:

step S1: acquiring running conditions and vehicle information, determining the combination oil pressure of a wet clutch, and determining the running required torque;

specifically, in the step S3:

Specifically, in the step S4:

the wet clutch oil pressure controller: according to the operation intention of a driver and the running condition of a vehicle, a double-layer fuzzy control strategy is adopted, in a second-layer fuzzy controller, the operation intention of the driver, the engine rotating speed and the difference between the rotating speeds of a master engine and a slave engine of a clutch are used as input, the combination or separation oil pressure of the clutch is used as output, and a fuzzy control rule is formulated according to the combination of the input of a combination oil pressure change rate fuzzy controller and the membership function of a fuzzy subset of an output variable to obtain a combination oil pressure change rate fuzzy control curved surface.

Specifically, the method comprises the steps of acquiring running conditions and vehicle information, wherein the running conditions and the vehicle information comprise a driver operation intention, a whole vehicle power demand and a battery pack SOC state;

in the formula: t is _dtar Is power source torque; t is _mtar 、T _etar The torque required by the next target driving motor and the engine respectively; t is _e 、T _m Actual torques of the current engine and the driving motor are respectively; x and Y are torque change rates of the engine and the driving motor respectively.

in particular, in said module M3:

Specifically, in the module M4:

In particular, in said module M4:

in the formula: t is _dtar Is power source torque; t is a unit of _mtar 、T _etar The torque required by the next target driving motor and the engine is respectively; t is a unit of _e 、T _m Actual torques of the current engine and the driving motor are respectively; x and Y are torque change rates of the engine and the driving motor respectively.

Example 2:

example 2 is a preferred example of example 1, and the present invention will be described in more detail.

The key and difficulty of starting dynamic process control are how to process the key problems of identification of driving intention, high and low speed of clutch combined oil pressure, torque distribution required by the whole vehicle, power source torque coordination control and the like in a short time. As shown in fig. 1, a control logic diagram of a dual-power source combined starting process of a plug-in hybrid vehicle is mainly divided into three major parts, which are respectively:

(1) Identifying a starting intention in consideration of a driver's operation;

(2) A maximum torque rate control based on a jerk limit;

(3) And controlling the power source and the clutch oil pressure.

Breakaway intent recognition taking into account driver operation:

a driver judges whether starting related conditions are met or not by reading information such as vehicle speed, pedal opening and change rate thereof, current SOC (state of charge), current running mode of the vehicle and the like, determines running required torque, and controls and outputs actual torque through a driving motor controller and an engine controller.

The idea of dynamic coordination control of the power source torque is to make the torque of two power sources (engine and driving motor) change in a process, so that the torque fluctuation from the two power sources to the wheel end through the speed change mechanism is relatively small. The kinetic equation can be expressed as:

in the formula: t is _dtar ，T _mtar ，T _etar The torque required by the next target driving motor and the engine respectively; t is _e ，T _m Actual torques of the current engine and the current driving motor are respectively; x and Y are respectively the torque change rates of the engine and the driving motor.

Maximum torque rate control based on jerk limit:

the torque response characteristics of different types of power sources have difference, the response of an engine is delayed, and the torque control of the power sources is difficult to directly carry out. In order to enable the engine to effectively follow the target torque change, the PID algorithm is used for converting the target torque of the engine into the opening degree of an accelerator pedal, and increment compensation is carried out on the opening degree. Drive motor with torque/speed capabilityWith the advantage of response, its output torque can be controlled directly by the torque command. Limiting j by the maximum impact of the whole vehicle _max The rate and magnitude of change of clutch engagement oil pressure can be obtained for control purposes. Meanwhile, the influence of the sudden change of the output torque of the engine on the smoothness of the vehicle starting process needs to be considered. Therefore, with the magnitude of the vehicle longitudinal shock as a target, limiting the engine maximum output torque and its rate of change can be expressed as:

in the formula: m is the load of the whole vehicle; r is the wheel radius; delta is a rotation mass conversion coefficient; i all right angle _m ·i ₂ Three-stage reduction ratio for driving the motor to the first input shaft; i.e. i _g Is the transmission speed ratio; i.e. i _m The speed ratio from the P2.5 driving motor to the output end of the main reducer is obtained; i.e. i _o1 The speed ratio of the main speed reducer 1 is obtained; t is _e 、T _m The actual torques of the engine and the P2.5 driving motor in the current mode are respectively.

Power source and clutch oil pressure control:

according to a control logic diagram of a dual-power source combined starting process of a plug-in hybrid electric vehicle, two fuzzy controllers designed in the text are respectively as follows: the driver operates the intention controller and the wet clutch oil pressure controller.

Driver operation intention controller: based on the opening degree alpha of the accelerator pedal and the change rate thereof

For input, the driver operation intention I is output. The operation intention of the driver is corresponding to different vehicle running torque demands through the opening degree of the accelerator pedal and the change rate of the opening degree.

Assume that the fuzzy language of accelerator pedal opening α is: { Very Small (VS), small (S), medium (M), large (B), very large (VB) }, basic discourse field ∈: [0,1](ii) a Rate of change of accelerator pedal opening

Is blurredThe language is: { negative large (NB), negative Medium (NM), negative Small (NS), zero (Z), positive Small (PS), positive Medium (PM), positive large (PB) }, basic domain of discourse e: [ -1,1](ii) a The fuzzy language of the driver's operational intention (I) is: { Very Small (VS), small (S), medium (M), large (B), very large (VB) }, basic discourse field ∈: [0,1]。

And (3) obtaining a fuzzy control curved surface of the operation intention of the driver according to the fuzzy subset membership function of the input and output variables of the fuzzy controller of the operation intention of the driver and by combining formulated fuzzy control rules, as shown in fig. 2.

Wet clutch oil pressure controller: taking the starting intention and the starting condition into consideration, adopting a double-layer fuzzy control strategy, taking the operation intention I of a driver as the input variable of a fuzzy controller of a second layer, and taking the driving intention I and the engine rotating speed omega of the second layer _e The rotating speed difference delta omega between the clutch main and the engine _e For input, the clutch engages or disengages oil pressure as output.

Assume that the fuzzy language of the driver's operation intention (I) is: { Very Small (VS), small (S), medium (M), large (B), very large (VB) }, basic discourse field ∈: [ -1,1]; the fuzzy language of the rotating speed difference | delta omega | of the clutch driving disk and the clutch driven disk is as follows: { Very Small (VS), small (S), medium (M), large (B), very large (VB) }, basic discourse field ∈: [0,1]; the fuzzy language of the clutch engagement or disengagement oil pressure (P) is: { negative large (VS), negative medium (S), negative small (MS), zero (S), positive small (MB), medium (B), positive large (VB) }, basic domain of discourse is in the middle: [0,1].

And (3) obtaining a fuzzy control curved surface combined with the oil pressure change rate according to the fuzzy subset membership function combined with the input and output variables of the fuzzy controller combined with the oil pressure change rate and the formulated fuzzy control rule, as shown in figure 3.

It is known to those skilled in the art that, in addition to implementing the system, apparatus and its various modules provided by the present invention in pure computer readable program code, the system, apparatus and its various modules provided by the present invention can be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like by completely programming the method steps. Therefore, the system, the device and the modules thereof provided by the present invention can be considered as a hardware component, and the modules included in the system, the device and the modules thereof for implementing various programs can also be considered as structures in the hardware component; modules for performing various functions may also be considered to be both software programs for performing the methods and structures within hardware components.

The foregoing description has described specific embodiments of the present invention. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims

1. A plug-in hybrid vehicle launch control method, comprising:

2. The plug-in hybrid vehicle launch control method according to claim 1, characterized in that:

acquiring running conditions and vehicle information, including a driver operation intention, a whole vehicle power demand and a battery pack SOC state;

in the formula: t is a unit of _dtar Is power source torque; t is _mtar 、T _etar The torque required by the next target driving motor and the engine respectively; t is _e 、T _m Actual torques of the current engine and the current driving motor are respectively; x and Y are respectively the torque change rates of the engine and the driving motor.

3. The plug-in hybrid vehicle startup control method according to claim 1, characterized in that in step S3:

4. The plug-in hybrid vehicle startup control method according to claim 1, characterized in that in step S4:

5. The plug-in hybrid vehicle startup control method according to claim 1, characterized in that in step S4:

6. A plug-in hybrid vehicle launch control system, comprising:

7. The plug-in hybrid vehicle launch control system of claim 1, characterized in that:

in the formula: t is a unit of _dtar Is power source torque; t is a unit of _mtar 、T _etar The torque required by the next target driving motor and the engine is respectively; t is _e 、T _m Actual torques of the current engine and the current driving motor are respectively; x and Y are respectively the torque change rates of the engine and the driving motor.

8. The plug-in hybrid vehicle launch control system of claim 1, wherein in the module M3:

9. The plug-in hybrid vehicle launch control system of claim 1, wherein in the module M4:

10. The plug-in hybrid vehicle launch control system of claim 1, wherein in the module M4: