CN111572534B

CN111572534B - Power-split type hybrid power truck brake safety protection mode switching control method

Info

Publication number: CN111572534B
Application number: CN202010257184.5A
Authority: CN
Inventors: 董恩源; 钟发平; 于海生; 程辉军; 盖福祥; 邹永强; 郭明林
Original assignee: Jiangxi Dingsheng New Material Technology Co ltd
Current assignee: Jiangxi Dingsheng New Material Technology Co ltd
Priority date: 2020-04-03
Filing date: 2020-04-03
Publication date: 2022-11-04
Anticipated expiration: 2040-04-03
Also published as: CN111572534A

Abstract

The invention provides a power split type hybrid truck brake safety protection mode switching control method, which comprises the steps of pre-charging a second clutch, controlling the second clutch to slip and drag an engine when pre-charging of the second clutch is completed and the rotation speed difference between the engine and a second motor is within a set interval C, then controlling the second clutch to reduce the transmission torque of the second clutch to 0, then controlling the engine to start oil injection, increasing the rotation speed of the engine by controlling the torque required by the engine, then controlling the second clutch to transmit the torque so that the rotation speed of the engine is gradually close to the rotation speed of the second motor, then controlling the second clutch to be closed, pre-charging a first clutch, controlling the first clutch to transmit the torque so that the rotation speed of a planet carrier is gradually close to the rotation speed of the engine when pre-charging of the first clutch is completed and the absolute value of the rotation speed difference between the engine and the planet carrier is smaller than a set threshold value H, and finally controlling the first clutch to be closed by a whole vehicle controller. The method is simple and feasible, and improves the driving safety and the system reliability.

Description

Power-split type hybrid power truck brake safety protection mode switching control method

Technical Field

The invention relates to the field of control of hybrid vehicles, in particular to a power split type switching control method for a brake safety protection mode of a hybrid truck.

Background

With the progress of technology, the requirements on the economy and the emission effect of trucks are becoming more and more strict, and hybrid trucks also become a technological development direction. The hybrid power system improves the economy and the emission effect of the whole vehicle, and simultaneously, a control system of the hybrid power system is more complex than that of a traditional vehicle, mode switching between various hybrid power modes and a pure electric mode exists, and the reliability and the smoothness of the mode switching are key difficulties. The power split type hybrid power truck has large mass, has large demand on braking force when in a long downhill working condition, has weak electric braking torque under the condition of high SOC of a power battery, avoids braking by stepping on a brake for a long time, avoids the situation that the SOC of the battery can not continuously rise to a dangerous interval, needs to switch the driving mode of a hybrid power transmission system to ensure driving safety, and controls and switches the driving mode of the hybrid power transmission system to achieve a better effect, so that the power split type hybrid power truck becomes a research direction of the hybrid power truck.

Disclosure of Invention

The invention aims to provide a simple and feasible power split type hybrid power truck brake safety protection mode switching control method, and the driving safety and the system reliability are improved.

The invention is realized by the following scheme:

a power split type hybrid truck braking safety protection mode switching control method is characterized in that when a vehicle is in an EV-3 driving mode, a vehicle control unit judges whether a user needs to switch a braking safety protection mode, if yes, a first brake B1 is kept on, and the method comprises the following steps:

s1: the vehicle control unit pre-charges the second clutch C2, and executes the step S2 when the pre-charging of the second clutch C2 is completed and the rotation speed difference between the engine and the second motor EM2 is within the set interval C;

s2: the vehicle control unit controls the second clutch C2 to slide and drag the engine, and when the rotating speed of the engine exceeds a set threshold value D, the step S3 is executed;

s3: the vehicle controller controls the torque transmitted by the second clutch C2 to be reduced to 0 according to a certain gradient delta V, controls the pressure of the second clutch C2 to be reduced to a pressure value corresponding to a kisspepoint state, and executes a step S4 when the rotating speed of the engine is reduced to a set threshold value E, wherein the set threshold value E is smaller than a set threshold value D;

s4: the vehicle control unit controls the engine to start oil injection, increases the rotating speed of the engine by controlling the torque required by the engine, and executes the step S5 when the rotating speed difference between the engine and the second motor EM2 is larger than a set threshold value F;

s5: the vehicle control unit controls the second clutch C2 to transmit torque so that the rotating speed of the engine is gradually close to the rotating speed of the second motor EM2, and when the absolute value of the rotating speed difference between the engine and the second motor EM2 is smaller than a set threshold value G, the step S6 is executed;

s6: the vehicle control unit controls the second clutch C2 to be closed, pre-charges the first clutch C1, simultaneously adjusts the rotating speed of the first planet carrier through the first motor and the second motor together, and executes the step S7 when the pre-charging of the first clutch C1 is completed and the absolute value of the rotating speed difference between the engine and the first planet carrier is smaller than a set threshold value H;

s7: the vehicle controller controls the first clutch C1 to transmit torque so that the rotating speed of the first planet carrier gradually approaches the rotating speed of the engine, and controls the first clutch C1 to be closed when the absolute value of the rotating speed difference between the engine and the first planet carrier is smaller than a set threshold value K, and the vehicle is switched from an EV-3 driving mode to an HEV-6 driving mode at the moment.

The set interval C is 0-1500 rpm, the set threshold D is 500-800 rpm, the set threshold E is 400-500 rpm, the set threshold F is-200 to-100 rpm, the set threshold G is 30-80 rpm, the set threshold H is 0-1000 rpm, and the set threshold K is 30-80 rpm.

The gradient delta V is 200-1000 Nm/s.

If the current accelerator pedal opening of the vehicle received by the vehicle controller is 0, the power battery charge retention SOC is greater than a set threshold A, the rotating speed of the outer gear ring is greater than a set threshold B, the set threshold A is 80% -95%, and the set threshold B is 900-1400 rpm, the vehicle controller judges that a user needs to switch the braking safety protection mode.

The power split type hybrid power truck braking safety protection mode switching control method is simple and feasible, and in the driving mode switching process, the first brake B1, the first clutch C1 and the second clutch C2 are correspondingly controlled, so that the vehicle is smoothly switched from the EV-3 driving mode to the HEV-6 driving mode, the vehicle can provide braking force in the continuous downhill process of high SOC, the electric quantity of a battery is protected to be controllable, and the driving safety and the system reliability are improved. According to the power split type hybrid power truck braking safety protection mode switching control method, the first clutch C1, the second clutch C2, the engine rotating speed and the lever posture are separately controlled in the mode switching process, the whole mode switching process is connected in series through a plurality of key conditions, the mode switching process is compact and continuous, the mode switching reliability is improved, and the mode switching time is shortened.

Drawings

FIG. 1 is a schematic structural view of a hybrid transmission used in the present invention;

fig. 2 is a control flowchart of a brake safeguard mode switching control method of the power split hybrid truck 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 structural schematic diagram of the hybrid power transmission device used in the invention is shown in fig. 1, and the main components of the hybrid power transmission device comprise a first motor EM1, a second motor EM2, an input shaft 1, a first brake B1, a second brake B2, a first clutch C1, a second clutch C2 and a planetary gear coupling mechanism 5, wherein the planetary gear coupling mechanism 5 comprises a single planetary row PG1 and a double planetary row PG2, the single planetary row PG1 comprises a first sun gear S1, a first planet gear P1, a first planet carrier PC1 and a first gear ring R1, the first planet gear P1 is mounted on the first planet carrier PC1, and the first planet gear P1 is respectively meshed with the first sun gear S1 and the first gear ring R1; the double-planet-row PG2 comprises a second sun gear S2, a second inner planet gear IP2, a second outer planet gear OP2, a second planet carrier PC2 and a second ring gear R2, the second inner planet gear IP2 and the second outer planet gear OP2 are both mounted on the second planet carrier PC2, the second inner planet gear IP2 is meshed with the second outer planet gear OP2, the second sun gear S2 is meshed with the second inner planet gear IP2, and the second ring gear R2 is meshed with the second outer planet gear OP 2; the second sun gear S2 is connected with a second rotor shaft 8 of a second motor EM2 through a first intermediate shaft 2 with a hollow inner part, the first sun gear S1 is connected with a first rotor shaft 7 on the first motor EM1 through a second intermediate shaft 3 with a hollow inner part, the first intermediate shaft 2 passes through the second intermediate shaft 3, a first planet carrier PC1 and a second planet carrier PC2 are connected to form a central shaft 4 with a hollow inner part, a first gear ring R1 and a second gear ring R2 are connected to form an output shaft 6, the input shaft 1 sequentially passes through the first intermediate shaft 2 and the central shaft 4, the input shaft 1 is connected with an output shaft of an engine ICE through a flywheel damper FW, one ends of a first brake B1 and a first clutch C1 are respectively connected with the central shaft 4, the other end of the first brake B1 is fixed on a gearbox shell 9, the other end of the first clutch C1 is connected with the input shaft 1, one end of the second clutch C2 is connected with the second rotor shaft 8 of the second motor EM2, the other end of the second clutch C2 is connected with the input shaft 1, one end of the second brake B2 is fixed on the gearbox shell 9. The structure of the hybrid transmission used in the present invention has been disclosed in a transmission for a rear-drive hybrid vehicle (publication No. CN 108099576A).

The hybrid transmission used in the present invention has a plurality of operating modes, and the control relationship between each operating mode and the shift element is shown in table 1, wherein good device indicates an open state, \ 9679and indicates a closed state.

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

Mode of operation	B1	B2	C1	C2
					EV-1	●	〇	〇	〇
EV-2	〇	●	〇	〇
					EV-3	〇	〇	〇	〇
HEV-1	〇	〇	●	〇
					HEV-2	●	〇	〇	●
HEV-3	〇	●	●	〇
					HEV-4	〇	●	〇	●
HEV-5	〇	〇	〇	●
					HEV-6	〇	〇	●	●
Parking charging-1	〇	〇	〇	●
					Parking charging-2	〇	〇	●	〇
Braking energy recovery mode	〇	〇	〇	〇
					Car reversing dieFormula (II)	●	〇	〇	〇

Example 1

A power split type hybrid truck braking safety protection mode switching control method is characterized in that a control flow chart is shown in fig. 2, when a vehicle is in an EV-3 driving mode, if the current accelerator pedal opening degree, namely the accelerator pedal opening degree, of the vehicle received by a vehicle controller is 0, the power battery charge keeping SOC is larger than a set threshold value A, the outer gear ring rotating speed is larger than a set threshold value B, the set threshold value A is 85%, the set threshold value B is 900rpm, the vehicle controller judges that a user needs to switch the braking safety protection mode, a first brake B1 is kept on, and the method is carried out according to the following steps:

s1: the vehicle control unit pre-charges the second clutch C2, sets the interval C to be 0-1500 rpm when the pre-charging of the second clutch C2 is completed and the rotating speed difference between the engine and the second motor EM2 is within the set interval C, and executes the step S2;

s2: the vehicle control unit controls the second clutch C2 to slide and drag the engine, when the rotating speed of the engine exceeds a set threshold D, the set threshold D is 500rpm, and step S3 is executed;

s3: the finished vehicle controller controls the transmission torque of the second clutch C2 to be reduced to 0 according to a certain gradient delta V, the gradient delta V is 600Nm/S, the pressure of the second clutch C2 is controlled to be reduced to a pressure value corresponding to a kisspeint state, when the rotating speed of the engine is reduced to a set threshold value E, the set threshold value E is smaller than a set threshold value D, the set threshold value E is 400rpm, and the step S4 is executed;

s4: the vehicle control unit controls the engine to start oil injection, increases the rotating speed of the engine by controlling the torque required by the engine, sets the threshold F to be-100 rpm when the rotating speed difference between the engine and the second motor EM2 is larger than the set threshold F, and executes the step S5;

s5: the vehicle control unit controls the second clutch C2 to transmit torque so that the rotating speed of the engine is gradually close to the rotating speed of the second motor EM2, when the absolute value of the difference between the rotating speeds of the engine and the second motor EM2 is smaller than a set threshold G, the set threshold G is 50rpm, and step S6 is executed;

s6: the vehicle control unit controls the second clutch C2 to be closed, pre-charges the first clutch C1, simultaneously adjusts the rotating speed of the first planet carrier PC1 through the first motor EM1 and the second motor EM2 together, sets the threshold H to be 1000rpm when the pre-charging of the first clutch C1 is completed and the absolute value of the rotating speed difference between the engine and the first planet carrier is smaller than the set threshold H, and executes the step S7;

s7: the vehicle control unit controls the first clutch C1 to transmit torque so that the rotating speed of the first planet carrier PC1 gradually approaches the rotating speed of the engine, when the absolute value of the difference between the rotating speeds of the engine and the first planet carrier PC1 is smaller than a set threshold K, the set threshold K is 50rpm, the vehicle control unit controls the first clutch C1 to be closed, and at the moment, the vehicle is switched from the EV-3 driving mode to the HEV-6 driving mode.

Example 2

A power split hybrid truck brake safety protection mode switching control method, the steps of which are substantially the same as those of the power split hybrid truck brake safety protection mode switching control method in embodiment 1, the difference being that: the threshold A was set at 80%, the threshold B was set at 1200rpm, the threshold D was set at 800rpm, the threshold E was set at 500rpm, the threshold F was set at-200 rpm, the threshold G was set at 80rpm, the threshold H was set at 200rpm, the threshold K was set at 80rpm, and the gradient DeltaV was 200Nm/s.

Example 3

A power split type hybrid truck brake safety protection mode switching control method, which has the steps basically the same as those of the power split type hybrid truck brake safety protection mode switching control method in embodiment 1, and is different in that: the threshold A was set at 95%, the threshold B was set at 1400rpm, the threshold D was set at 700rpm, the threshold E was set at 450rpm, the threshold F was set at-150 rpm, the threshold G was set at 30rpm, the threshold H was set at 500rpm, the threshold K was set at 30rpm, and the gradient DeltaV was 1000Nm/s.

Claims

1. A power split type hybrid power truck brake safety protection mode switching control method is characterized by comprising the following steps: the hybrid power transmission device comprises a first electric machine (EM 1), a second electric machine (EM 2), an input shaft, a first brake (B1), a second brake (B2), a first clutch (C1) and a second clutch (C2)

The single planet row comprises a first sun gear, a first planet carrier and a first gear ring, the first planet gear is arranged on the first planet carrier, and the first planet gear is respectively meshed with the first sun gear and the first gear ring; the double planet row comprises a second sun wheel, a second inner planet wheel, a second outer planet wheel, a second planet carrier and a second gear ring, the second inner planet wheel and the second outer planet wheel are both arranged on the second planet carrier and meshed with each other, the second sun wheel is meshed with the second inner planet wheel, and the second gear ring is meshed with the second outer planet wheel; the second sun gear is connected with a second rotor shaft of a second motor (EM 2) through a first intermediate shaft with a hollow inner part, the first sun gear is connected with a first rotor shaft on the first motor (EM 1) through the second intermediate shaft with the hollow inner part, the first intermediate shaft passes through the second intermediate shaft, a first planet carrier and a second planet carrier are connected to form a central shaft with the hollow inner part, a first gear ring and a second gear ring are connected to form an output shaft, the input shaft sequentially passes through the first intermediate shaft and the central shaft, the input shaft is connected with an output shaft of an engine through a flywheel vibration damper, a first brake (B1) and one end of a first clutch (C1) are respectively connected to the central shaft, the other end of the first brake (B1) is fixed on a gearbox shell, the other end of the first clutch (C1) is connected to the input shaft, one end of a second clutch (C2) is connected to a second rotor shaft of the second motor (EM 2), the other end of the second clutch (C2) is connected to the input shaft, one end of the second brake (B2) is connected to the gearbox shell, and the other end of the second brake (B2) is fixed on the gearbox shell; when the first brake (B1), the second brake (B2), the first clutch (C1) and the second clutch (C2)

When the vehicle is in the open state, the vehicle is in an EV-3 driving mode; the vehicle is in the HEV-6 drive mode when the first brake (B1) and the second brake (B2) are in the open state and the first clutch (C1) and the second clutch (C2) are in the closed state; when the vehicle is in an EV-3 driving mode, the vehicle control unit judges whether a user needs to switch a braking safety protection mode, if so, the vehicle control unit keeps a first brake (B1) open and carries out the following steps:

s1: the vehicle control unit pre-charges the second clutch (C2), and executes the step S2 when the pre-charging of the second clutch (C2) is completed and the rotating speed difference between the engine and the second motor (EM 2) is within the set interval C;

s2: the vehicle control unit controls a second clutch (C2) to slip and drag the engine, and when the rotating speed of the engine exceeds a set threshold value D, a step S3 is executed;

s3: the vehicle control unit controls the transmission torque of the second clutch (C2) to be reduced to 0 according to a certain gradient delta V, controls the pressure of the second clutch (C2) to be reduced to a pressure value corresponding to a kisspepoint state, and executes a step S4 when the rotating speed of the engine is reduced to a set threshold value E, wherein the set threshold value E is smaller than a set threshold value D;

s4: the vehicle control unit controls the engine to start oil injection, increases the rotating speed of the engine by controlling the torque required by the engine, and executes the step S5 when the rotating speed difference between the engine and a second motor (EM 2) is larger than a set threshold value F;

s5: the vehicle control unit controls the second clutch (C2) to transmit torque so that the rotating speed of the engine gradually approaches to the rotating speed of the second motor (EM 2), and when the absolute value of the difference between the rotating speeds of the engine and the second motor (EM 2) is smaller than a set threshold value G, the step S6 is executed;

s6: the vehicle controller controls the second clutch (C2) to be closed, pre-charges the first clutch (C1), simultaneously adjusts the rotating speed of the first planet carrier through the first motor and the second motor together, and executes the step S7 when the pre-charging of the first clutch (C1) is completed and the absolute value of the rotating speed difference between the engine and the first planet carrier is smaller than a set threshold value H;

s7: the vehicle control unit controls the first clutch (C1) to transmit torque so that the rotating speed of the first planet carrier gradually approaches the rotating speed of the engine, and controls the first clutch (C1) to be closed when the absolute value of the rotating speed difference between the engine and the first planet carrier is smaller than a set threshold value K, and the vehicle is switched from an EV-3 driving mode to an HEV-6 driving mode at the moment.

2. The power split hybrid truck brake safeguard mode switch control method of claim 1, characterized by: the set interval C is 0-1500 rpm, the set threshold D is 500-800 rpm, the set threshold E is 400-500 rpm, the set threshold F is-200 to-100 rpm, the set threshold G is 30-80 rpm, the set threshold H is 0-1000 rpm, and the set threshold K is 30-80 rpm.

3. The power-split hybrid truck brake safeguard mode switch control method of claim 1, characterized in that: the gradient delta V is 200-1000 Nm/s.

4. The power split hybrid truck brake safeguard mode switch control method according to any one of claims 1 to 3, characterized by: if the current accelerator pedal opening of the vehicle received by the vehicle controller is 0, the power battery charge retention SOC is greater than a set threshold A, the rotating speed of the outer gear ring is greater than a set threshold B, the set threshold A is 80% -95%, and the set threshold B is 900-1400 rpm, the vehicle controller judges that a user needs to switch the braking safety protection mode.