阅读说明：本技术 一种混动车型模式切换时发动机转速控制方法及控制器 (Method and controller for controlling engine rotating speed during mode switching of hybrid vehicle ) 是由 赵田芳 权卫平 李海波 田丰民 王恺 于 2021-09-06 设计创作，主要内容包括：本发明涉及汽车发动机转速控制领域,具体涉及一种混动车型模式切换时发动机转速控制方法及控制器。根据行驶过程中车辆离合器的状态,将发动机P1转速控制模式划分为了三种不同控制模式,然后综合考虑离合器两端的转速的差异以及发动机的油耗和最佳曲线,在不同控制模式下分别得出不同的发动机目标转速和转速控制请求扭矩,能够有效减少混动模式切换时车辆的顿挫感,并能够提高车辆的驾驶性和经济性；同时,采用PID控制算法,计算闭环控制模式和正负扭矩都可以模式下的发动机转速控制请求扭矩,能够有效提高发动机扭矩控制的准确性和稳定性,进一步提升了车辆高速行驶时的平稳性。(The invention relates to the field of automobile engine rotating speed control, in particular to an engine rotating speed control method and a controller during mode switching of a hybrid vehicle. According to the state of a vehicle clutch in the driving process, the control mode of the rotating speed of the engine P1 is divided into three different control modes, then the difference of the rotating speeds at two ends of the clutch and the oil consumption and the optimal curve of the engine are comprehensively considered, different target rotating speeds of the engine and different torque requested by the rotating speed control are obtained under different control modes, the suspension feeling of the vehicle during switching of the hybrid mode can be effectively reduced, and the driving performance and the economical efficiency of the vehicle can be improved; meanwhile, the PID control algorithm is adopted to calculate the engine rotating speed control request torque in a closed-loop control mode and a positive and negative torque mode, so that the accuracy and the stability of the engine torque control can be effectively improved, and the stability of the vehicle in high-speed running is further improved.)

1. A method for controlling the rotating speed of an engine during mode switching of a hybrid vehicle is characterized in that: in the running process of an engine of the hybrid electric vehicle, when the vehicle switches the hybrid mode, different engine speed control strategies are executed according to different states of a clutch, and the specific control strategies are as follows:

when the clutch is not engaged and tends to be engaged, the engine P1 speed control enters a closed loop control mode, and the target engine speed V at the moment is set₁Equal to the speed V of the motor P3_P3Then calculating the target engine speed V₁And actual engine speed V₀Differential Speed of_Diff1And calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₁；

When the clutch is completely combined, the rotating speed control of the engine P1 enters a positive torque control mode, firstly, the oil consumption and the optimal curve of the engine are obtained through the universal characteristic curve of the engine, then, the requested charging power of the engine is obtained according to the requested power of a driver and the charging state of a vehicle battery, and then, the target rotating speed V of the engine is obtained according to the requested charging power of the engine and the optimal curve of the engine₂At this time, the engine speed control requests the torque T₂Slowly rising from a negative value to 0, and finally rotating speed control request torque T in the parallel mode₂Always kept at 0 Nm;

when the clutch is completely disengaged, the engine P1 speed control enters a positive and negative torque possible mode, when the engine target speed V₃Equal to a fixed preset value M, and then calculating a target engine speed V₃Hair-making deviceActual rotational speed V of motor₀Differential Speed of_Diff3And calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₃。

2. The method for controlling the engine speed during the mode switching of the hybrid vehicle according to claim 1, comprising the steps of:

s1, judging whether the mixed mode requests to change from series connection to parallel connection, if so, executing step S2, otherwise, maintaining the original mixed mode logic;

s2, judging whether the clutch is allowed to be combined and is ready to be combined, if so, executing a step S3, and if not, maintaining the original hybrid mode logic;

s3, the P1 speed control of the engine enters a closed loop control mode, and the target speed V of the engine at the moment is calculated₁；

S4, calculating the target engine speed V₁And actual engine speed V₀Differential Speed of_Diff1；

S5, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₁；

S6, judging whether the clutch is yes, finishing the combination, if yes, executing the step S7, and if not, maintaining the original mixed mode logic;

s7, the engine P1 speed control enters a positive torque only control mode, and the engine target speed V at the moment is calculated₂；

S8, current speed control request torque T₂Slowly rises to 0Nm from a negative value and is always kept at 0 Nm;

s9, judging whether the mixed mode requests to change from parallel connection to series connection, if so, executing step S10, otherwise, maintaining the original mixed mode logic;

s10, controlling the P1 speed of the engine to enter a positive and negative torque possible mode, and calculating the target speed V of the engine at the moment₃；

S11, calculating the target engine speed V₃And actual engine speed V₀Differential Speed of_Diff3；

S12, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₃。

3. The method for controlling the engine speed during switching of the hybrid vehicle mode according to claim 1 or 2, wherein the PID control algorithm specifically includes the steps of:

s1, according to the Speed_DiffnLooking up the engine control coefficient table to determine the torque time constant lambda_nAnd intake system time constant τ_AirnAnd coefficient of rotation f_n；

S2, calculating P item parameter K controlled by PID_PnI term parameter K_InD term parameter K_DnThe concrete formula is as follows:

in the formula, J is the rotational inertia of the engine;

s3, calculating P torque T of the rotating speed control request torque_PnI term torque T_InD term torque T_DnThe concrete formula is as follows:

in the formula (d)_speednIs the rate of change of engine speed, C is a constant;

s4, calculating the rotating speed control request torque T_n＝T_Pn+T_In+T_Dn；

In the above steps, n is 1 when the P1 speed control enters the closed-loop control mode, and n is 3 when the P1 speed control enters the positive and negative torque enable mode.

4. Method for controlling the engine speed during a mode change of a hybrid vehicle according to claim 1 or 2, characterized in that the closed-loop control mode, in particular the hybrid mode, has a tendency to change from the series mode to the parallel mode, when the target engine speed V is reached₁Equal to the speed V of the motor P3_P3。

5. The method for controlling the engine speed during the mode switching of the hybrid vehicle according to claim 1 or 2, wherein the positive torque only control mode, specifically the hybrid mode, is a parallel mode, first the fuel consumption and the optimal curve of the engine are obtained according to the universal characteristic curve of the engine, then the requested charging power of the engine is obtained according to the requested power of the driver and the state of charge of the vehicle battery, and then the target engine speed V is obtained according to the requested charging power of the engine and the optimal curve of the engine₂。

6. Method for controlling the engine speed during mode switching in a hybrid vehicle according to claim 1 or 2, wherein the positive and negative torques can be switched, in particular, the hybrid mode is a series mode, when the target engine speed V is₃Equal to a fixed preset value M.

7. The method of controlling the engine speed at the time of switching of the hybrid vehicle mode according to claim 3, characterized in that: the engine control coefficient table is obtained by empirically summarizing a plurality of engine tests.

8. A vehicle controller comprising a memory, a processor and a program stored on the memory and executable on the processor, wherein the processor when executing the program implements the method of any one of claims 1 to 7.

9. A non-transitory readable storage medium on which a program is stored, characterized in that the program realizes the method according to any one of claims 1 to 7 when executed by a vehicle controller.

10. A hybrid vehicle, characterized in that: comprising the vehicle controller of claim 8.

Technical Field

The invention relates to the field of automobile engine rotating speed control, in particular to an engine rotating speed control method and a controller during mode switching of a hybrid vehicle.

Background

With the increasing popularization of new energy hybrid vehicles, the hybrid vehicles run in a unique series-parallel mode and are mutually switched in series and parallel during running, so that the requirements of hybrid vehicle types on the drivability are particularly outstanding. When a hybrid vehicle type is shifted from a series mode to a parallel mode, that is, when a clutch is about to be engaged, in order to prevent an impact of a wheel speed on an engine, the impact and the jerk are generally reduced by reducing the engine speed.

However, in the prior art, the control of firstly reducing the rotation speed of the engine and then increasing the rotation speed is usually based on the torque response capability of the engine, so that the response is relatively slow, and the control precision is low, so that the drivability problems such as vehicle bump under different speeds and different throttles are easily caused.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: provided are a method and a controller for controlling the engine speed when switching modes of a hybrid vehicle, which can keep the vehicle stable, reduce the jerking feeling, and improve the drivability and the economical efficiency of the vehicle when switching modes of the hybrid vehicle during high-speed driving.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for controlling the rotating speed of an engine during mode switching of a hybrid vehicle is characterized in that: in the running process of an engine of the hybrid electric vehicle, when the vehicle switches the hybrid mode, different engine speed control strategies are executed according to different states of a clutch, and the specific control strategies are as follows:

when the clutch is not engaged and tends to be engaged, the engine P1 speed control enters a closed loop control mode, and the target engine speed V at the moment is set₁Equal to the speed V of the motor P3_P3Then calculating the target engine speedSpeed V₁And actual engine speed V₀Differential Speed of_Diff1And calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₁；

When the clutch is completely combined, the rotating speed control of the engine P1 enters a positive torque control mode, firstly, the oil consumption and the optimal curve of the engine are obtained through the universal characteristic curve of the engine, then, the requested charging power of the engine is obtained according to the requested power of a driver and the charging state of a vehicle battery, and then, the target rotating speed V of the engine is obtained according to the requested charging power of the engine and the optimal curve of the engine₂At this time, the engine speed control requests the torque T₂Slowly rising from a negative value to 0, and finally rotating speed control request torque T in the parallel mode₂Always kept at 0 Nm;

when the clutch is completely disengaged, the engine P1 speed control enters a positive and negative torque possible mode, when the engine target speed V₃Equal to a fixed preset value M, and then calculating a target engine speed V₃And actual engine speed V₀Differential Speed of_Diff3And calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₃。

Further, the method for controlling the rotating speed of the engine during the mode switching of the hybrid vehicle specifically comprises the following steps:

s1, judging whether the mixed mode requests to change from series connection to parallel connection, if so, executing step S2, otherwise, maintaining the original mixed mode logic;

s2, judging whether the clutch is allowed to be combined and is ready to be combined, if so, executing a step S3, and if not, maintaining the original hybrid mode logic;

s3, the P1 speed control of the engine enters a closed loop control mode, and the target speed V of the engine at the moment is calculated₁；

S4, calculating the target engine speed V₁And actual engine speed V₀Differential Speed of_Diff1；

S5, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₁；

S6, judging whether the clutch is yes, finishing the combination, if yes, executing the step S7, and if not, maintaining the original mixed mode logic;

s7, the engine P1 speed control enters a positive torque only control mode, and the engine target speed V at the moment is calculated₂；

S8, current speed control request torque T₂Slowly rises to 0Nm from a negative value and is always kept at 0 Nm;

s9, judging whether the mixed mode requests to change from parallel connection to series connection, if so, executing step S10, otherwise, maintaining the original mixed mode logic;

s10, controlling the P1 speed of the engine to enter a positive and negative torque possible mode, and calculating the target speed V of the engine at the moment₃；

S11, calculating the target engine speed V₃And actual engine speed V₀Differential Speed of_Diff3；

S12, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₃。

Further, the PID control algorithm specifically includes the following steps:

s1, according to the Speed_DiffnLooking up the engine control coefficient table to determine the torque time constant lambda_nAnd intake system time constant τ_AirnAnd coefficient of rotation f_n；

S2, calculating P item parameter K controlled by PID_PnI term parameter K_InD term parameter K_DnThe concrete formula is as follows:

in the formula, J is the rotational inertia of the engine;

s3, calculating P torque T of the rotating speed control request torque_PnI term torque T_InD term torque T_DnThe concrete formula is as follows:

in the formula (d)_speednIs the rate of change of engine speed, C is a constant;

s4, calculating the rotating speed control request torque T_n＝T_Pn+T_In+T_Dn；

In the above steps, n is 1 when the P1 speed control enters the closed-loop control mode, and n is 3 when the P1 speed control enters the positive and negative torque enable mode.

Further, the closed-loop control mode, specifically the hybrid mode, tends to change from the series mode to the parallel mode when the target engine speed V is reached₁Equal to the speed V of the motor P3_P3。

Further, the positive torque only control mode, specifically the hybrid mode, is a parallel mode, firstly the oil consumption and the optimal curve of the engine are obtained through the universal characteristic curve of the engine, then the requested charging power of the engine is obtained according to the requested power of the driver and the charge state of the vehicle battery, and then the target rotating speed V of the engine is obtained according to the requested charging power of the engine and the optimal curve of the engine₂。

Further, the positive torque and the negative torque can be in a mode, specifically, the hybrid mode is a series mode, and the target rotating speed V of the engine is obtained at the moment₃Equal to a fixed preset value M.

Further, the engine control coefficient table is obtained by empirically summarizing a plurality of engine tests.

A vehicle controller comprising a memory, a processor and a program stored in the memory and executable on the processor, wherein the processor implements the method for controlling the engine speed at the time of switching the hybrid vehicle mode when executing the program.

A non-transitory readable storage medium having a program stored thereon, wherein the program, when executed by a vehicle controller, implements the above-described engine speed control method at the time of switching of the hybrid vehicle mode.

A hybrid vehicle, characterized in that: including the vehicle controller described above.

Compared with the prior art, the invention has the following main advantages:

1. according to the state of a vehicle clutch in the driving process, the control mode of the rotating speed of the engine P1 is divided into three different control modes, then the difference of the rotating speeds at two ends of the clutch and the oil consumption and the optimal curve of the engine are comprehensively considered, different target rotating speeds of the engine and different torque requested by the rotating speed control are obtained under different control modes, the suspension feeling of the vehicle during switching of the hybrid mode can be effectively reduced, and the driving performance and the economical efficiency of the vehicle can be improved;

2. by adopting a PID control algorithm, the engine rotating speed control request torque under a closed-loop control mode and a positive and negative torque available mode is calculated, the accuracy and the stability of the engine torque control can be effectively improved, and the stability of the vehicle in high-speed running is further improved.

Drawings

FIG. 1 is a schematic diagram of a main electric control drive assembly of a hybrid electric vehicle;

FIG. 2 is a flowchart illustrating a control method according to the present invention.

In the figure: 1. an engine; 2. an integrated starter/generator integrated motor (ISG); 3. a drive motor; 4. a high voltage battery; 5. a clutch.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

It should be noted that, according to the implementation requirement, each step/component described in the present application can be divided into more steps/components, and two or more steps/components or partial operations of the steps/components can be combined into new steps/components to achieve the purpose of the present invention.

The main electric control driving assembly of the hybrid electric vehicle is shown in fig. 1, and comprises an engine 1, an integrated starting/power generation integrated motor (ISG)2, a driving motor 3, a high-voltage battery 4 and a clutch 5.

The ISG is directly connected with the engine for starting, power generation and assistance; the engine and the driving motor output power together, and a clutch is arranged behind the engine and used for switching a transmission state. In a pure electric state, the engine and the ISG motor do not work, and the power battery provides electric energy to drive the motor to drive the vehicle; in a series state, the clutch is disengaged, the engine does not participate in driving the vehicle, and is only responsible for driving the ISG motor to generate power and supply the power to the driving motor to drive the vehicle, and redundant power generation is stored in the power battery; in the parallel state, the clutch is engaged and the engine is directly used to drive the vehicle.

In the process of controlling the rotating speed of P1, the ISG outputs torque due to the regulation and control of the ISG, and if the torque is a negative value, the torque can be represented as engine torque to charge the ISG; if the torque is positive, it can be characterized as engine torque requiring the ISG to electrically drive.

The invention provides an engine speed control method during hybrid vehicle mode switching, which specifically comprises three parts of division of an engine P1 speed control mode, calculation of an engine target speed and calculation of a speed control request torque.

During high-speed driving of the hybrid vehicle, when the hybrid mode is switched, the engine P1 rotational speed Control mode may be classified into a Closed Loop Control mode (Closed Loop Control), a positive torque only Control mode, and a positive/negative torque all possible mode according to the vehicle clutch state.

(1) A Closed Loop Control mode (Closed Loop Control), specifically, when the engine is running, the clutch of the hybrid electric vehicle is not combined and the clutch tends to be combined, the rotating speed of the engine P1 is controlled to enter the Closed Loop Control mode;

(2) the method comprises the steps that only a positive torque control mode is adopted, specifically, a clutch of the hybrid electric vehicle is completely combined, and when the hybrid mode enters a parallel mode, the rotating speed of an engine P1 is controlled to enter the only positive torque control mode;

(3) the positive and negative torques can be in a mode, specifically, the clutch of the hybrid electric vehicle is completely disengaged, and when the hybrid mode enters the series mode, the rotating speed of the engine P1 is controlled to enter the positive and negative torque modes.

Further, the calculation of the target engine speed is closely related to the engine speed control mode.

(1) When the P1 speed control enters the closed-loop control mode, the engine target speed V₁Equal to the speed V of the motor P3_P3The clutch is used for ensuring that the speeds of two ends of the clutch are the same when the clutch is combined, ensuring that the flywheel of an engine cannot be impacted when the clutch is combined, and avoiding pause in driving perception;

(2) when the P1 rotating speed control enters the positive torque control mode, firstly, the oil consumption and the optimal curve of the engine are obtained through the universal characteristic curve of the engine, then the requested charging power of the engine is obtained according to the requested power of a driver and the state of charge (SOC) of a vehicle battery, and then the target rotating speed V of the engine is obtained according to the requested charging power of the engine and the optimal curve of the engine₂；

(3) Engine target speed V when P1 speed control enters into both positive and negative torque enabled modes₃Equal to a fixed preset value M, 1050rpm in this embodiment.

Further, the calculation of the rotational speed control torque is also related to the engine rotational speed control mode.

(1) When the P1 speed control enters a positive and negative torque available mode or a closed loop control mode, the clutch of the hybrid electric vehicle is in the process of disengaging or disengaging to engaging, in order to maintain the engine speed as the target speed, a PID control algorithm is adopted, and the target speed V of the engine is used_n(n＝1、3)And actual engine speed V₀Differential Speed of_Diffn(n is 1 or 3) as a control target, calculates a parameter of the PID, and then calculates the rotational speed control request torque T based on the parameter of the PID_n(n＝1、3)。

The method for calculating the rotating speed control request torque by adopting the PID control algorithm comprises the following specific steps:

s1, according to the Speed_DiffnLooking up an empirically summarized table of engine control coefficients to determine the torque time constant λ_nAnd intake system time constant τ_AirnAnd coefficient of rotation f_n；

S2, calculating P item parameter K controlled by PID_PnI term parameter K_InD term parameter K_DnThe concrete formula is as follows:

in the formula, J is the rotational inertia of the engine;

s3, calculating P torque T of the rotating speed control request torque_PnI term torque T_InD term torque T_DnThe concrete formula is as follows:

in the formula (d)_speednIs the rate of change of engine speed, C is a constant;

s4, calculating the rotating speed control request torque T_n＝T_Pn+T_In+T_Dn；

In the above steps, n is 1 when the P1 speed control enters the closed-loop control mode, and n is 3 when the P1 speed control enters the positive and negative torque enable mode.

The engine control coefficient table is obtained by summarizing multiple engine test experiences, is input into a vehicle controller in advance, and is inquired and read when an algorithm program runs; the requested torque is obtained by requesting the torque of the motor P1 and adjusting the engine speed by charging and discharging to maintain the engine speed near an optimum speed.

(2) When P1 speed control enters into positive torque control mode only, the clutch of the hybrid electric vehicle is completely combined, the hybrid mode enters into parallel mode, and the engine speed control requests torque T₂Slowly rising from a negative value to 0, and finally rotating speed control request torque T in the parallel mode₂Always at 0 Nm.

The invention provides a method for controlling the rotating speed of an engine during mode switching of a hybrid vehicle, which comprises the following steps:

s1, judging whether the mixed mode requests to change from series connection to parallel connection, if so, executing step S2, otherwise, maintaining the original mixed mode logic;

s2, judging whether the clutch is allowed to be combined and is ready to be combined, if so, executing a step S3, and if not, maintaining the original hybrid mode logic;

s3, the P1 speed control of the engine enters a closed loop control mode, and the target speed V of the engine at the moment is calculated₁；

S4, calculating the target engine speed V₁And actual engine speed V₀Differential Speed of_Diff1；

S5, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₁；

S6, judging whether the clutch is yes, finishing the combination, if yes, executing the step S7, and if not, maintaining the original mixed mode logic;

s7, the engine P1 speed control enters a positive torque only control mode, and the engine target speed V at the moment is calculated₂；

S8, current rotationSpeed control requested torque T₂Slowly rises to 0Nm from a negative value and is always kept at 0 Nm;

s9, judging whether the mixed mode requests to change from parallel connection to series connection, if so, executing step S10, otherwise, maintaining the original mixed mode logic;

s10, controlling the P1 speed of the engine to enter a positive and negative torque possible mode, and calculating the target speed V of the engine at the moment₃；

S11, calculating the target engine speed V₃And actual engine speed V₀Differential Speed of_Diff3；

S12, calculating the torque T requested by the engine speed control at the moment by adopting a PID control algorithm₃。

By adopting the method for controlling the engine speed during switching the hybrid vehicle modes, the control mode of the engine P1 speed is divided into three different control modes according to the state of a vehicle clutch in the driving process, then the difference of the speeds at two ends of the clutch and the oil consumption and the optimal curve of the engine are comprehensively considered, different target engine speeds and different control request torques of the speed are respectively obtained under different control modes, the suspension feeling of the vehicle during switching the hybrid mode can be effectively reduced, and the driving performance and the economical efficiency of the vehicle can be improved.

Meanwhile, the PID control algorithm is adopted to calculate the engine rotating speed control request torque in a closed-loop control mode and a positive and negative torque mode, so that the accuracy and the stability of the engine torque control can be effectively improved, and the stability of the vehicle in high-speed running is further improved.

Based on the method, the invention also provides:

a vehicle controller comprising a memory, a processor and a program stored on the memory and executable on the processor, the processor implementing the method when executing the program.

A non-transitory readable storage medium having stored thereon a program that, when executed by a vehicle controller, implements the above-described engine speed control method at the time of switching of the hybrid vehicle mode.

A hybrid electric vehicle includes the vehicle controller.

The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.