CN-121977066-A - Gear shifting control method for two-gear pure electric commercial vehicle controlled by TCU

CN121977066ACN 121977066 ACN121977066 ACN 121977066ACN-121977066-A

Abstract

The invention relates to the field of whole vehicle control of new energy automobiles, in particular to a gear shifting control method of a two-gear pure electric commercial vehicle controlled by a TCU, which comprises the steps of S1, powering on the vehicle, waking up the vehicle VCU, TCU, MCU, BMS and various controllers, detecting whether a driver requests to drive in a D gear after high-pressure Ready is applied, S2, collecting vehicle state information in real time by the TCU, S3, identifying working conditions, identifying the intention of the driver by the TCU according to the collected accelerator pedal opening and brake pedal signals, judging the current driving working conditions according to the collected vehicle speed and vehicle load information, S4, TCU generating a target gear instruction based on a preset basic economical gear shifting curve by combining dynamic correction factors, and S5, carrying out gear shifting cooperative control, thereby solving the defects in a single-gear speed reducer scheme and a multi-gear AMT scheme at the current stage.

Inventors

LI ZHIHUA
ZENG QINGLIANG
DING LIN
DUAN JIQIANG
LIU XIANGYONG
HAN FENG
JIAO YANAN

Assignees

浙江飞碟汽车制造有限公司
山东五征集团有限公司

Dates

Publication Date: 20260505
Application Date: 20260408

Claims (8)

1. A gear shifting control method for a two-gear pure electric commercial vehicle controlled by a TCU is characterized by comprising the following specific steps: step S1, powering on the vehicle, waking up the vehicle VCU, TCU, MCU, BMS and each controller, and detecting whether a driver requests to drive in a D gear after high-voltage Ready is powered on by the TCU; step S2, the TCU acquires vehicle state information in real time, wherein the vehicle state information comprises vehicle speed, accelerator pedal opening, brake pedal signals, motor rotation speed and torque, current gear state, battery SOC and vehicle load information; step S3, carrying out working condition identification, wherein the TCU identifies the intention of a driver according to the acquired opening degree of the accelerator pedal and the brake pedal signal, and judges the current running working condition according to the acquired vehicle speed and the vehicle load information; Step S4, comprehensively shifting decisions, namely, a TCU (transmission control unit) generates a target gear instruction based on a preset basic economy shift curve and combines a dynamic correction factor, wherein the dynamic correction factor corrects the basic economy shift curve according to the intention of a driver, the load of a vehicle and the current running working condition identified in the step S3; And S5, performing gear shifting cooperative control, wherein when the target gear generated in the step S4 is inconsistent with the current gear, the TCU is used as a main controller, and the following operation steps are sequentially executed: Step S5.1, in the torque reducing stage, the TCU sends an accurate torque zeroing request to the MCU, and the MCU controls the driving motor to quickly and smoothly reduce the output torque to zero and feeds back the actual torque and the rotating speed to the TCU; S5.2, in the gear shifting stage, after the torque of the motor meets the condition, the TCU controls a gear shifting executing mechanism of the transmission to shift into a neutral gear; s5.3, the TCU controls the motor to regulate the speed, and presynchronizing with the rotating speed of the target gear; S5.4, the MCU feeds back the actual torque and the rotating speed to the TCU; Step S5.5, the TCU judges the gear-engaging speed difference and controls the execution mechanism of the speed changer to engage in a target gear; Step S5.6, in the torque recovery stage, the TCU calculates and requests a target driving torque according to the current opening of the accelerator pedal, and the MCU controls the motor torque to smoothly rise to the target value to recover power output; And S6, performing fault diagnosis and executing a safety strategy.
2. The gear shifting control method of the two-gear pure electric vehicle controlled by the TCU according to claim 1, wherein the vehicle load information in the step S2 is directly obtained through a load sensor.
3. The gear shifting control method of the two-gear pure electric vehicle controlled by the TCU according to claim 1, wherein the vehicle load information in the step S2 is obtained through estimation of the relation between the motor output torque and the vehicle acceleration.
4. The gear shifting control method of the two-gear pure electric vehicle controlled by the TCU according to claim 1, wherein the step S3 is characterized in that the step S3 is used for identifying the intention of a driver and comprises the steps of gentle acceleration, abrupt acceleration, cruising and deceleration identified according to the opening degree of an accelerator pedal and the change rate of the accelerator pedal, and the current driving working condition comprises heavy load climbing, descending and low-speed creeping.
5. The gear shifting control method of the two-gear pure electric vehicle controlled by the TCU according to claim 4, wherein the basic economical gear shifting curve in the step S4 is a preset two-parameter gear shifting Map based on the vehicle speed and the accelerator pedal opening.
6. The gear shifting control method for the two-gear pure electric vehicle controlled by the TCU according to claim 1 is characterized in that the dynamic correction factor in the step S4 is that the gear shifting is delayed when the sudden acceleration intention is identified, the gear shifting speed threshold is increased when the heavy load working condition is identified, and the gear shifting is forbidden or the gear shifting is actively reduced when the climbing working condition is identified.
7. The method for controlling gear shifting of a two-gear pure electric vehicle controlled by a TCU according to claim 1, wherein in the step S5.3, the TCU calculates a target speed regulation rotating speed according to a difference value between the current motor rotating speed and the target gear rotating speed, and sends a speed regulation command to the MCU until the rotating speed difference is smaller than a preset threshold value.
8. The gear shifting control method of the two-gear pure electric vehicle controlled by the TCU according to claim 1, wherein the fault diagnosis and execution safety strategy in the step S6 is that the TCU continuously monitors key parameters such as the position of a gear shifting actuator, the synchronous state of the rotating speed of a motor and the like, if gear shifting is overtime or abnormal, the TCU immediately interrupts the gear shifting process, tries to recover to the original gear or enter a limp home mode, records a fault code and ensures the basic running safety of the vehicle.

Description

Gear shifting control method for two-gear pure electric commercial vehicle controlled by TCU Technical Field The invention relates to the field of whole vehicle control of new energy automobiles, in particular to a gear shifting control method of a two-gear pure electric commercial vehicle controlled by a TCU. Background Currently, the motorized process of commercial vehicles, especially light trucks, is increasingly accelerated, and compared with passenger vehicles, the motorized light truck has the characteristics of heavy load, complex working conditions (frequent start and stop, climbing, large load change) and the like, which puts higher demands on the dynamic property, economy and reliability of a driving system. The single-gear speed reducer scheme is simple in structure, low in cost and high in reliability, is a mainstream configuration at present, but has the defects that in order to meet large torque requirements such as full-load climbing, peak power and torque of a motor need to be selected to be large, so that the motor works in a low-efficiency area for a long time under a common medium-high speed cruising working condition, energy consumption is high, and endurance mileage is obviously shortened, meanwhile, the high-speed running of the motor also brings noise and abrasion problems, the multi-gear AMT scheme is usually 4-gear or 6-gear, the traditional fuel vehicle gearbox technology is used for reference, the advantages are that the motor can work in a high-efficiency area through multi-gear switching, endurance and power performance are improved, the defects are that the structure is complex, the cost is high, the gear shifting control strategy is complex (a motor needs to be coordinated, a gearbox and a clutch), power interruption or impact is easy to occur in a gear shifting process, driving safety and goods are influenced, and the reliability is challenged. Therefore, a technical blank to be solved is provided between the economy of the single-gear scheme and the performance advantage of the multi-gear AMT scheme, and a two-gear speed change scheme which has the advantages of simple structure, intelligent control, moderate cost and capability of remarkably improving the working efficiency of the motor is provided. At present, a gear shifting control method for a two-gear pure electric commercial vehicle controlled by a TCU is provided to solve the problems in the background art. Disclosure of Invention The invention aims to provide a gear shifting control method for a two-gear pure electric commercial vehicle controlled by a TCU, which is used for processing vehicle state information through TCU integration, executing a set of intelligent gear shifting decisions considering driving intention, vehicle load and real-time efficiency, and coordinating a driving motor MCU to carry out accurate torque adjustment, thereby realizing quick, smooth and economic two-gear switching and effectively improving the overall performance and reliability of the vehicle. A gear shifting control method for a two-gear pure electric vehicle controlled by a TCU comprises the following specific steps: Step S1, powering on the vehicle, waking up the vehicle VCU, TCU, MCU, BMS and each controller, and detecting whether a driver requests to drive in a D gear after high-voltage Ready is powered on by the TCU; step S2, the TCU acquires vehicle state information in real time, wherein the vehicle state information comprises vehicle speed, accelerator pedal opening, brake pedal signals, motor rotation speed and torque and vehicle load information; step S3, carrying out working condition identification, wherein the TCU identifies the intention of a driver according to the acquired opening degree of the accelerator pedal and the brake pedal signal, and judges the current running working condition according to the acquired vehicle speed and the vehicle load information; Step S4, comprehensively shifting decisions, namely, a TCU (transmission control unit) generates a target gear instruction based on a preset basic economy shift curve and combines a dynamic correction factor, wherein the dynamic correction factor corrects the basic economy shift curve according to the intention of a driver, the load of a vehicle and the current running working condition identified in the step S3; And S5, performing gear shifting cooperative control, wherein when the target gear generated in the step S4 is inconsistent with the current gear, the TCU is used as a main controller, and the following operation steps are sequentially executed: Step S5.1, in the torque reducing stage, the TCU sends an accurate torque zeroing request to the MCU, and the MCU controls the driving motor to quickly and smoothly reduce the output torque to zero and feeds back the actual torque and the rotating speed to the TCU; S5.2, in the gear shifting stage, after the torque of the motor meets the condition, the TCU controls a gear shifting executing mechanism of the