CN110293959B

CN110293959B - Hybrid power driving mode switching control method of power split type hybrid power vehicle

Info

Publication number: CN110293959B
Application number: CN201910431972.9A
Authority: CN
Inventors: 邹永强; 钟发平; 张彤; 申辛未; 程辉军; 董恩源
Original assignee: Corun Hybrid Power Technology Co Ltd
Current assignee: Jiangxi Dingsheng New Material Technology Co ltd
Priority date: 2019-05-23
Filing date: 2019-05-23
Publication date: 2022-07-08
Anticipated expiration: 2039-05-23
Also published as: CN110293959A

Abstract

The invention provides a hybrid power driving mode switching control method of a power split type hybrid vehicle, wherein a first clutch is pre-charged, the torque of a first brake is reduced, when the torque of the first brake is smaller than A and the pre-charging of the first clutch is finished, the rotating speed of the first planet carrier is increased, the torque of the second clutch is reduced, when the difference between the engine speed and the large motor speed is greater than C and the difference between the engine speed and the first planet carrier speed is less than D, maintaining the second clutch torque, increasing the first clutch torque and increasing the first carrier rotational speed, when the difference value between the engine speed and the first planet carrier speed is less than E, the torque of the second clutch is reduced, the engine speed is controlled, and when the absolute value of the difference value between the engine speed and the first planet carrier speed is less than H, the first clutch torque is increased until the first clutch is completely closed. The method is simple and feasible, and has good driving safety and comfort.

Description

Hybrid power driving mode switching control method of power split type hybrid power vehicle

Technical Field

The invention relates to the field of control of hybrid vehicles, in particular to a hybrid power driving mode switching control method of a power split type hybrid vehicle.

Background

In the driving process of the hybrid electric vehicle, the hybrid electric vehicle can be switched between hybrid power driving modes or pure battery driving modes according to different conditions, and can also be switched from the hybrid power driving mode to the pure electric driving mode.

Disclosure of Invention

The invention aims to provide a power split hybrid power vehicle hybrid power driving mode switching control method which is simple and feasible, has smoother vehicle in the driving mode switching process and better driving safety and comfort.

The invention is realized by the following scheme:

a power split hybrid vehicle hybrid driving mode switching control method is characterized in that when the vehicle is in an HEV-2 driving mode, the vehicle speed is lower than 45Km/h, and the opening degree of an accelerator pedal is less than or equal to 30%, the vehicle is switched to the hybrid driving mode, and the method comprises the following steps:

s1: the vehicle controller pre-charges the first clutch C0, reduces the torque of the first brake B1 to 0 by a gradient Δ V1, so that the first brake B1 is opened, and executes step S2 when the first brake torque is smaller than a set threshold a and the pre-charging of the first clutch C0 is completed;

s2: increasing the rotating speed of the first planet carrier PC1 by taking the rotating speed of the engine as a target rotating speed, reducing the torque of the second clutch C1 to a value obtained by subtracting a set threshold B from the flywheel torque of the engine by a gradient delta V2, enabling a rotating speed difference to appear at two ends of the second clutch C1, and executing a step S3 when the difference value between the rotating speed of the engine and the rotating speed of the large motor E2 is larger than the set threshold C and the difference value between the rotating speed of the engine and the rotating speed of the first planet carrier PC1 is smaller than the set threshold D;

s3: maintaining the torque of the second clutch C1, increasing the torque of the first clutch C0 to a value obtained by subtracting the torque of the second clutch C1 from the flywheel torque of the engine by a gradient delta V3, increasing the rotating speed of the first planet carrier by taking the rotating speed of the engine as a target rotating speed, and executing a step S4 when the difference value between the rotating speed of the engine and the rotating speed of the first planet carrier is smaller than a set threshold value E;

s4: reducing the torque of the second clutch C1 to 0 by a gradient DeltaV 4, so that the second clutch C1 is opened, controlling the torque of the first clutch C0 by a PID algorithm by taking the maximum value of the first planet carrier rotating speed plus a set threshold value F, the rotating speed of the large motor E2 plus the set threshold value F and a set threshold value G as a target rotating speed, and executing a step S5 when the torque of the second clutch C1 is reduced to 0;

s5: controlling the engine speed by controlling the torque of the first clutch C0 through a PID algorithm with the first planet carrier speed as a target speed, and executing a step S6 when the absolute value of the difference between the engine speed and the first planet carrier speed is less than a set threshold value H;

s6: the first clutch C0 torque is increased by the gradient Δ V5 until the first clutch C0 is fully closed, at which time the vehicle hybrid drive mode is switched to HEV-4.

Further, the set threshold A is 5-10 Nm, the set threshold B is 30-60 Nm, the set threshold C is 50-100 rpm, the set threshold D is 1500-2500 rpm, the set threshold E is 500-1000 rpm, the set threshold F is 30-100 rpm, the set threshold G is 1000-1300 rpm, and the set threshold H is 30-80 rpm.

Further, the gradient delta V1 is 800-1000 Nm/s, the gradient delta V2 is 500-800 Nm/s, the gradient delta V3 is 300-600 Nm/s, the gradient delta V4 is 600-900 Nm/s, and the gradient delta V5 is 1000-1500 Nm/s.

The power split hybrid vehicle hybrid power driving mode switching control method is simple and feasible, the first clutch C0, the second clutch C1 and the first brake B1 are respectively and correspondingly controlled under different conditions in the driving mode switching process, so that the vehicle is smoothly switched from the HEV-2 driving mode to the HEV-4 driving mode, the vehicle deceleration requirement and the economic requirement are met, the mode switching process is compact and continuous, and the mode switching time is shortened.

Drawings

FIG. 1 is a schematic block diagram of a hybrid powertrain system for use with the present invention;

FIG. 2 is an equivalent lever diagram of the HEV-4 drive mode of the hybrid powertrain for use with the present invention;

FIG. 3 is an equivalent lever diagram of the HEV-2 drive mode of the hybrid powertrain for use with the present invention;

fig. 4 is a control flowchart of a hybrid drive mode switching control method of the power split hybrid vehicle in embodiment 1.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the description of the examples.

The structure of the hybrid transmission system used in the present invention is schematically shown in fig. 1, and its main components include a small electric machine E1, a large electric machine E2, a first brake B1, a first clutch C0, a second clutch C1, a planetary gear coupling mechanism composed of a first single planetary row PG1 and a second single planetary row PG2, and a third single planetary row PG3, the first single planetary row PG1 includes a first planet carrier PC1, a first planet carrier P1, a first sun gear S1, and a first ring gear R1, the second single planetary row PG1 includes a second planet carrier PC1, a second planet carrier P1, a second sun gear S1, and a second ring gear R1, the first sun gear S1 of the first single planetary row PG1 is connected to the first rotor shaft 2 of the small electric machine E4, the second sun gear S1 of the second single planetary row PG1 is connected to the first sun gear S1 of the small electric machine E1, the third sun gear S1 of the second single row PG1 is connected to the third planet carrier P1, the third sun gear S1, the third planet carrier P1, the input shaft 1 is connected with an output shaft of an engine ICE, one end of a first clutch C0 is connected with a first planet carrier PC1, and the other end of the first clutch C0 is connected with the input shaft 1; one end of a second clutch C1 is connected to the second rotor shaft 3 of the large electric machine E2, the other end of the second clutch C1 is connected to the input shaft 1, one end of a first brake B1 is connected to the first carrier PC1, and one end of a second brake B2 is connected to the first rotor shaft 2 of the small electric machine E1. The structure of the hybrid power transmission system used in the present invention has been disclosed in a transmission for a front-engine hybrid vehicle (publication No. CN 108105358A).

The hybrid power transmission system used in the present invention has a plurality of operating modes, and the control relationship between the operating modes and the shift elements is shown in table 1, wherein good represents the open state and ● represents the closed state.

TABLE 1 control relationship between the respective operating modes and the shifting elements

Mode of operation	C0	C1	B1	B2
					EV-1	〇	〇	●	〇
EV-2	〇	〇	〇	●
					EV-3	〇	〇	〇	〇
EV-1RD	〇	〇	●	〇
					HEV-1	〇	●	〇	〇
HEV-2	〇	●	●	〇
					HEV-3	〇	●	〇	●
HEV-4	●	〇	〇	〇
					HEV-5	●	〇	〇	●
HEV-6	●	●	〇	〇

Fig. 2 shows an equivalent lever diagram of the fourth-gear hybrid drive mode (HEV-4 drive mode), fig. 3 shows an equivalent lever diagram of the second-gear hybrid drive mode (HEV-2 drive mode), fig. 2 and 3 show a left ordinate indicating a rotational speed, nS1 indicating a first sun gear rotational speed, nS2 indicating a second sun gear rotational speed, nPC1 indicating a first carrier rotational speed, and nR1 indicating a first ring gear rotational speed.

Example 1

s1: the vehicle control unit pre-charges the first clutch C0, reduces the torque of the first brake B1 to 0 by a gradient delta V1, and takes a value in 800-1000 Nm/S for the gradient delta V1, so that the first brake B1 is opened, and when the torque of the first brake is smaller than a set threshold A and the pre-charging of the first clutch C0 is completed, the value of the set threshold A is taken in 5-10 Nm, and the step S2 is executed;

s2: the method comprises the steps that the rotating speed of a first planet carrier PC1 is increased by taking the rotating speed of an engine as a target rotating speed, the torque of a second clutch C1 is reduced to a value obtained by subtracting a set threshold B from the torque of an engine flywheel by a gradient delta V2, the value of the gradient delta V2 is 500-800 Nm/S, the value of the set threshold B is 30-60 Nm, so that a rotating speed difference occurs between two ends of a second clutch C1, when the difference value between the rotating speed of the engine and the rotating speed of a large motor E2 is larger than the set threshold C and the difference value between the rotating speed of the engine and the rotating speed of the first planet carrier PC1 is smaller than a set threshold D, the value of the set threshold C is 50-100 rpm, the value of the set threshold D is taken at 1500-2500 rpm, and a step S3 is executed;

s3: maintaining the torque of the second clutch C1, increasing the torque of the first clutch C0 to a value obtained by subtracting the torque of the second clutch C1 from the flywheel torque of the engine by a gradient delta V3, taking a value of the gradient delta V3 in 300-600 Nm/S, increasing the rotating speed of the first planet carrier by taking the rotating speed of the engine as a target rotating speed, taking a value of a set threshold E in 500-1000 rpm when the difference value between the rotating speed of the engine and the rotating speed of the first planet carrier is smaller than the set threshold E, and executing a step S4;

s4: reducing the torque of a second clutch C1 to 0 by a gradient delta V4, and taking a value of the gradient delta V4 in 600-900 Nm/S to open the second clutch C1, controlling the torque of a first clutch C0 by a PID algorithm by taking the maximum value of the first carrier rotating speed plus a set threshold F, the rotating speed of a large motor E2 plus the set threshold F and a set threshold G as a target rotating speed, wherein the set threshold F takes a value in 30-100 rpm, the set threshold G takes a value in 1000-1300 rpm, and when the torque of the second clutch C1 is reduced to 0, executing a step S5;

s5: controlling the torque of a first clutch C0 by taking the rotating speed of a first planet carrier as a target rotating speed through a PID algorithm to control the rotating speed of an engine, and when the absolute value of the difference value between the rotating speed of the engine and the rotating speed of the first planet carrier is smaller than a set threshold value H, taking the value of the set threshold value H in 30-80 rpm, and executing a step S6;

s6: and increasing the torque of the first clutch C0 by a gradient delta V5 until the first clutch C0 is completely closed, wherein the gradient delta V5 is taken in a range of 1000-1500 Nm/s, and the hybrid driving mode of the vehicle is switched to the HEV-4.

Claims

1. A power split hybrid vehicle hybrid drive mode switching control method is characterized in that: the hybrid power transmission system comprises a small motor, a large motor, a first brake (B1), a first clutch (C0), a second clutch (C1), a planetary gear coupling mechanism consisting of a first single planetary row and a second single planetary row, and a third single planetary row, wherein the first single planetary row comprises a first planet carrier (PC1), a first planet gear, a first sun gear and a first gear ring, the second single planetary row comprises a second planet carrier, a second planet gear, a second sun gear and a second gear ring, the first sun gear of the first single planetary row is connected with a first rotor shaft of the small motor, the second sun gear of the second single planetary row is connected with a second rotor shaft of the large motor, the third single planetary row comprises a third planet carrier, a third planet gear, a third sun gear and a third gear ring, an input shaft is connected with an output shaft of an engine, one end of the first clutch (C0) is connected with a first planet carrier (PC1), the other end of the first clutch (C0) is connected to the input shaft; one end of a second clutch (C1) is connected to a second rotor shaft of the large motor, the other end of the second clutch (C1) is connected to the input shaft, one end of a first brake (B1) is connected to a first planet carrier (PC1), and one end of a second brake (B2) is connected to a first rotor shaft of the small motor; when the first clutch (C0) and the second brake (B2) are in an open state and the second clutch (C1) and the first brake (B1) are in a closed state, the vehicle is in an HEV-2 drive mode; when the first clutch (C0) is in the closed state and the second clutch (C1), the first brake (B1) and the second brake (B2) are in the open state, the vehicle is in an HEV-4 drive mode; when the vehicle is in an HEV-2 driving mode, the vehicle speed is lower than 45Km/h, and the opening degree of an accelerator pedal is less than or equal to 30%, the vehicle is switched to the hybrid driving mode, and the method comprises the following steps:

s1: the vehicle controller pre-charges the first clutch (C0), reduces the torque of the first brake (B1) to 0 by a gradient delta V1, and executes step S2 when the torque of the first brake is smaller than a set threshold A and the pre-charging of the first clutch (C0) is completed;

s2: increasing the rotation speed of the first planet carrier (PC1) by taking the engine rotation speed as a target rotation speed, reducing the torque of the second clutch (C1) to a value obtained by subtracting a set threshold B from the engine flywheel torque by a gradient delta V2, and executing a step S3 when the difference value between the engine rotation speed and the rotation speed of the large motor (E2) is larger than the set threshold C and the difference value between the engine rotation speed and the rotation speed of the first planet carrier (PC1) is smaller than a set threshold D;

s3: maintaining the torque of the second clutch (C1), increasing the torque of the first clutch (C0) to a value obtained by subtracting the torque of the second clutch (C1) from the engine flywheel torque by a gradient DeltaV 3, increasing the first carrier rotating speed by taking the engine rotating speed as a target rotating speed, and executing a step S4 when the difference value between the engine rotating speed and the first carrier rotating speed is less than a set threshold value E;

s4: reducing the torque of the second clutch (C1) to 0 by using the gradient delta V4, controlling the torque of the first clutch (C0) by a PID algorithm to control the engine speed by taking the maximum value of the first planet carrier speed plus a set threshold value F, the speed of the large motor (E2) plus the set threshold value F and the set threshold value G as a target speed, and executing step S5 when the torque of the second clutch (C1) is reduced to 0;

s5: controlling the engine speed by controlling the torque of the first clutch (C0) through a PID algorithm with the first planet carrier speed as a target speed, and executing step S6 when the absolute value of the difference between the engine speed and the first planet carrier speed is less than a set threshold value H;

s6: the first clutch (C0) torque is increased with the gradient Δ V5 until the first clutch (C0) is fully closed, at which time the vehicle hybrid drive mode is switched to HEV-4.

2. The power split hybrid vehicle hybrid drive mode switching control method according to claim 1, characterized in that: the set threshold A is 5-10 Nm, the set threshold B is 30-60 Nm, the set threshold C is 50-100 rpm, the set threshold D is 1500-2500 rpm, the set threshold E is 500-1000 rpm, the set threshold F is 30-100 rpm, the set threshold G is 1000-1300 rpm, and the set threshold H is 30-80 rpm.

3. The power split hybrid vehicle hybrid driving mode switching control method according to claim 1 or 2, characterized in that: the gradient delta V1 is 800-1000 Nm/s, the gradient delta V2 is 500-800 Nm/s, the gradient delta V3 is 300-600 Nm/s, the gradient delta V4 is 600-900 Nm/s, and the gradient delta V5 is 1000-1500 Nm/s.