CN113386574B

CN113386574B - Monitoring method for torque direction of electric vehicle, vehicle control unit and vehicle

Info

Publication number: CN113386574B
Application number: CN202110870739.8A
Authority: CN
Inventors: 裴鹏宇; 李宗华; 严钦山; 杨官龙
Original assignee: Chongqing Changan New Energy Automobile Technology Co Ltd
Current assignee: Deep Blue Automotive Technology Co ltd
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2022-05-31
Anticipated expiration: 2041-07-30
Also published as: CN113386574A

Abstract

The scheme relates to a monitoring method for the torque direction of an electric automobile, a vehicle controller and an automobile, wherein the method comprises the following steps: collecting an accelerator pedal signal, and receiving a gear signal, a vehicle speed signal, a brake pedal signal, a torque increasing and decreasing request signal, a battery long-time discharge power signal, a motor long-time executable maximum torque signal, a motor rotating speed signal and a high-voltage accessory power consumption signal; determining the required torque of the whole vehicle according to a vehicle speed signal, an accelerator pedal signal, a battery long-time discharge power signal, a motor long-time executable maximum torque signal, a high-voltage accessory consumed power signal, a motor rotating speed signal and a torque increasing and decreasing request signal; determining the current operating condition of the whole vehicle and a corresponding required torque limit threshold value according to the vehicle speed, the gear, the brake pedal and the accelerator pedal signals; and arbitrating whether the torque direction of the finished automobile required torque is correct or not according to the finished automobile required torque and the required torque limit threshold value, and outputting the target finished automobile required torque to the motor based on an arbitration result.

Description

Monitoring method for torque direction of electric vehicle, vehicle control unit and vehicle

Technical Field

The invention relates to the technical field of pure electric vehicles, in particular to a method for monitoring the torque direction of an electric vehicle, a vehicle control unit and a vehicle.

Background

The problems of energy crisis, environmental pollution, greenhouse effect and the like are increasingly serious, so that new energy automobiles, particularly pure electric automobiles, become a necessary trend for the revolution of the automobile industry. The pure electric vehicle has the advantages of high NVH quality, simple structure, energy conservation, environmental protection, economy, strong dynamic property and the like, is widely concerned by scientific research institutions and enterprises, but the market problems of the electric vehicle are frequent, and the safety of the electric vehicle is also concerned more and more.

The pure electric vehicle uses a power battery as an energy source, a driving motor as a power source, the battery transmits energy to the driving motor through a high-voltage wire harness, and the driving motor transmits torque to wheels through a main speed reducer, a differential and a half shaft to drive the vehicle to run. Since the pure electric vehicle has no transmission, and the forward and backward movement of the vehicle are completely realized by the forward rotation and the reverse rotation of the driving motor, the correctness of the torque request direction is very important when the torque request of the vehicle is calculated. In the actual real vehicle test and road test, the phenomenon that the vehicle steps on the accelerator and goes backwards when passing a certain state occurs, and the problem is that great potential safety hazards exist if the vehicle on the market appears. In order to ensure the safety of personnel, it is important to design a method and a system for monitoring the torque direction of an electric vehicle. In the patent of electric vehicle and torque monitoring method and system thereof (application number: 201710899851.8), a torque monitoring method of an electric vehicle is disclosed, wherein an estimated torque of the vehicle is estimated through a battery voltage, a current and a rotating speed of a motor, and torque verification is performed according to the estimated torque, a required torque and a current working condition to judge whether the torque of the electric vehicle is abnormal or not. However, such monitoring has a disadvantage in the actual implementation process, and it is necessary to consider that there is an abnormality after the vehicle has been shown to be defective and the estimated torque estimated from the battery voltage, the current, and the rotational speed of the motor has been checked against the required torque, which has a certain hysteresis. In the patent "torque monitoring method and system for electric vehicle" (application number: 201410396603.8), the actual torque of the motor is calculated according to the vehicle operation signal and the vehicle state signal, whether the vehicle control system has a fault or not is judged, the torque is adjusted according to the fault, when the system is normal, the actual output torque of the motor is taken as the required torque, when the fault occurs, the torque is adjusted as the required torque, the torque limit value is calculated according to the vehicle operation signal, the state signal and the capability of the part, and the required torque is limited within the limited torque range calculated by the capability of the part. According to the description, the method can monitor the output torque so that it cannot jump or exceed reasonable limits. However, this method has a certain disadvantage that the output required torque exceeds the limited torque range of the component capability calculation, and the motor cannot be executed when receiving the required torque, which is relatively poor in effect, when the required torque changes, the required torque smoothly rises or falls according to the magnitude of the slope limit value, the slope limit value cannot affect the dynamic property of the vehicle, the torque change can change at a relatively fast rate, the effect is difficult to achieve the ideal effect, and although the output torque is monitored, the torque direction is not monitored. From the currently published patents, basically, a state signal of a finished automobile part is collected to calculate an actual execution torque to verify a required torque, or a monitoring module adopts a simplified version of a functional module to calculate a monitoring torque to verify the required torque, or the monitoring change rate, the required torque is limited according to the part capacity, and the like.

Disclosure of Invention

According to the monitoring method for the torque direction of the electric automobile, the vehicle controller and the automobile, the direction of the required torque is calculated by adopting a redundancy calculation mode while the required torque is calculated by the vehicle controller, the redundancy calculation logic is simple and effective, and is different from the required torque calculation logic, so that the situation that the vehicle runs reversely at low speed and the vehicle is unexpectedly provided with large reverse torque to drag to cause personnel injury when the vehicle runs at high speed can be avoided.

The technical scheme of the invention is as follows:

the invention provides a method for monitoring the torque direction of an electric vehicle, which is applied to a vehicle control unit and comprises the following steps:

acquiring an accelerator pedal signal, and receiving a gear signal sent by a gear controller, a vehicle speed signal, a brake pedal signal, a torque increasing and decreasing request signal, a battery long-time discharge power signal, a motor long-time executable maximum torque signal and a motor rotating speed signal, which are sent by a motor, and a high-voltage accessory power consumption signal, which is sent by a thermal management control device;

determining the required torque of the whole vehicle according to a vehicle speed signal, an accelerator pedal signal, a battery long-time discharge power signal, a motor long-time executable maximum torque signal, a high-voltage accessory consumed power signal, a motor rotating speed signal and a torque increasing and decreasing request signal;

determining the current running working condition of the whole vehicle and a required torque limit threshold value of the whole vehicle under the current running working condition according to the vehicle speed signal, the gear signal, the brake pedal signal and the accelerator pedal signal;

and arbitrating whether the torque direction of the required torque of the whole vehicle is correct or not according to the determined required torque of the whole vehicle and the required torque limit threshold value of the whole vehicle under the current operating condition, and outputting the target required torque of the whole vehicle to a motor based on an arbitration result.

Preferably, the method further comprises:

and if the CAN communication is required to be shut down when the fault is detected, shutting down the CAN communication and stopping outputting the target finished automobile required torque to the motor.

Preferably, the step of determining the required torque of the whole vehicle according to the vehicle speed signal, the accelerator pedal signal, the battery long-time discharge power signal, the motor long-time executable maximum torque signal, the high-voltage accessory consumed power signal, the motor rotating speed signal and the torque increasing and decreasing request signal comprises:

performing table look-up on the vehicle speed signal and the accelerator pedal signal according to a preset relation to obtain an initial driver required torque;

firstly, solving a power difference value between the long-time discharge power of the battery and the consumed power of the high-voltage accessory, dividing the power difference value by the rotating speed of the motor, and finally multiplying the ratio of the power difference value to the rotating speed of the motor by a preset coefficient to obtain the maximum torque of a driver which can be supported by an energy source;

taking the initial driver required torque, the driver maximum torque which can be supported by an energy source and the maximum torque which can be executed in a long time as the driver required torque;

judging whether an increasing and decreasing torsion intervention function is activated in the increasing and decreasing torsion torque request signal;

if the torque increasing and decreasing intervention function is activated, taking the requested torque in the torque increasing and decreasing request signal as the required torque of the whole vehicle;

and if the torque increasing and decreasing pre-starting function is not activated, taking the torque required by the driver as the torque required by the whole vehicle.

Preferably, the steps of determining the current operation condition of the whole vehicle and the required torque limit threshold value of the whole vehicle under the current operation condition according to the vehicle speed signal, the gear signal, the brake pedal signal and the accelerator pedal signal include:

if the gear signal indicates that the gear is a forward gear, the vehicle speed signal indicates that the vehicle speed is lower than a first preset value, and the brake pedal signal indicates that the brake pedal is not stepped, determining that the current running working condition of the whole vehicle is a first working condition that the whole vehicle is in slow forward motion, and determining that the required torque limiting threshold value is a first threshold value, wherein the first threshold value is a negative value between a first preset negative value and a second preset negative value;

if the gear signal indicates that the gear is in reverse gear, the vehicle speed signal indicates that the vehicle speed is lower than a second preset value, and the brake pedal signal indicates that the brake pedal is not stepped on, determining that the current running working condition of the whole vehicle is a second working condition that the whole vehicle is in slow reverse, and determining that the required torque limiting threshold value is a second threshold value, wherein the second threshold value is a negative value between a third preset negative value and a fourth preset negative value;

if the gear signal indicates that the gear is a forward gear, the vehicle speed signal indicates that the vehicle speed is higher than a third preset value, the accelerator pedal signal indicates that the opening of an accelerator pedal is larger than a first preset opening, and the brake pedal signal indicates that a brake pedal is not stepped, determining that the current running working condition of the whole vehicle is a third working condition that the whole vehicle is in forward acceleration, and determining that a required torque limiting threshold value is zero; the third preset value is greater than the first preset value;

if the gear signal indicates that the gear is a reverse gear, the vehicle speed signal indicates that the vehicle speed is higher than a fourth preset value, the accelerator pedal signal indicates that the opening of an accelerator pedal is larger than a second preset opening, and the brake pedal signal indicates that a brake pedal is not stepped, determining that the current running working condition of the whole vehicle is a fourth working condition that the whole vehicle is in accelerated reverse, and determining that a required torque limiting threshold value is zero; the fourth preset value is greater than the second preset value.

Preferably, the step of arbitrating whether the torque direction of the vehicle demand torque is correct or not according to the determined vehicle demand torque and a demand torque limit threshold of the vehicle under the current operating condition, and outputting the target vehicle demand torque to the motor based on the arbitration result includes:

if the whole vehicle is currently in a first working condition, judging whether the required torque of the whole vehicle is greater than a first preset value;

if the torque direction of the finished automobile required torque is smaller than or equal to the torque direction of the finished automobile required torque, arbitrating the torque direction error of the finished automobile required torque, and outputting the target finished automobile required torque with a value of zero to a motor; if so, arbitrating that the torque direction of the finished automobile required torque is correct, determining the finished automobile required torque as the target finished automobile required torque and outputting the target finished automobile required torque to a motor;

if the whole vehicle is currently in a second working condition, judging whether the required torque of the whole vehicle is greater than a second preset value;

if the torque direction of the finished automobile required torque is smaller than or equal to the target finished automobile required torque, arbitrating that the torque direction of the finished automobile required torque is correct, and determining the finished automobile required torque as the target finished automobile required torque to be output to a motor; if the current vehicle demand torque is larger than the preset vehicle demand torque, arbitrating that the torque direction of the vehicle demand torque is wrong, and outputting the target vehicle demand torque with a value of zero to a motor;

if the whole vehicle is currently in a third working condition, judging whether the required torque of the whole vehicle is larger than zero or not;

if the torque direction of the finished automobile required torque is judged to be correct, the finished automobile required torque is determined as the target finished automobile required torque and is output to a motor; if the torque direction is smaller than zero, arbitrating the torque direction error of the finished automobile required torque, and outputting the target finished automobile required torque with the value of zero to the motor;

if the whole vehicle is in a fourth working condition currently, judging whether the required torque of the whole vehicle is smaller than zero or not;

if the torque direction of the finished automobile required torque is judged to be correct, the finished automobile required torque is determined as the target finished automobile required torque and is output to a motor; if the torque direction of the whole vehicle required torque is larger than zero, the torque direction of the whole vehicle required torque is arbitrated to be wrong, and the target whole vehicle required torque with the value of zero is output to the motor.

Preferably, the vehicle control unit receives signals through the gear controller, the chassis controller, the battery, the motor and the thermal management control device of the CAN bus, and the vehicle control unit performs CAN frame loss check, cyclic redundancy check and counting check on the signals received from the CAN bus;

the whole vehicle controller collects accelerator pedal signals through two hard-wired lines, and the whole vehicle controller conducts power supply voltage over-upper-limit diagnosis or power supply voltage over-lower-limit diagnosis, voltage over-upper-limit diagnosis or voltage over-lower-limit diagnosis and rationality check on the accelerator pedal signals collected by the two hard-wired lines.

The invention also provides a vehicle control unit, comprising:

the system comprises an input module, a main controller module and an output module;

the main controller module includes: a demand request calculation unit and a demand torque direction calculation unit connected to the input module, and a demand request direction arbitration unit connected to the demand request calculation unit and the demand torque direction calculation unit; the demand request direction arbitration unit is connected with the output module;

the input module is used for acquiring an accelerator pedal signal, receiving a gear signal sent by a gear controller, a vehicle speed signal sent by a chassis controller, a brake pedal signal, a torque increasing and decreasing request signal, a battery long-time discharge power signal sent by a battery, a motor long-time executable maximum torque signal and a motor rotating speed signal sent by a motor, and a high-voltage accessory consumed power signal sent by a thermal management control unit;

the demand request calculation unit is used for determining the demanded torque of the whole vehicle according to a vehicle speed signal, an accelerator pedal signal, a battery long-time discharge power signal, a motor long-time executable maximum torque signal, a high-voltage accessory consumed power signal, a motor rotating speed signal and a torque increasing and decreasing request signal;

the required torque direction calculation unit is used for determining the current running working condition of the whole vehicle and a required torque limit threshold value of the whole vehicle under the current running working condition according to the vehicle speed signal, the gear signal, the brake pedal signal and the accelerator pedal signal;

the demand request direction arbitration unit arbitrates whether the torque direction of the whole vehicle demand torque is correct or not according to the determined whole vehicle demand torque and the demand torque limit threshold value of the whole vehicle under the current operation working condition, and outputs the target whole vehicle demand torque to the motor through the output module based on the arbitration result.

Preferably, the vehicle control unit further comprises:

the monitoring controller module is connected with the output module;

the monitoring controller module is used for sending a CAN communication shutdown request signal to the output module when monitoring that the main controller module has a fault; the master controller module failure includes: program flow faults of the main controller module and operation logic faults of the main controller;

the output module is specifically used for shutting off CAN communication and stopping outputting the target finished automobile required torque to the motor if a CAN communication shutting-off request signal is received.

Preferably, the monitoring controller module sends a question to the main controller module at regular time in each driving cycle process, the main controller module feeds back an answer output based on the question, the monitoring controller module compares the answer output by the main controller module with a preset answer which is stored in advance and corresponds to the question, and if the comparison is not consistent, the main controller module is determined to be in fault; otherwise, determining that the main controller module has no fault.

The invention also provides an automobile comprising the vehicle control unit.

The invention has the beneficial effects that:

aiming at the situation that the direction of the required torque is calculated by the whole vehicle controller in a redundant calculation mode while the required torque is calculated, the redundant calculation logic is simple and effective, and is different from the required torque calculation, so that the situation that the vehicle runs reversely at a low speed and is unexpectedly dragged by a large reverse torque to cause personnel injury when the vehicle runs at a high speed can be avoided.

Drawings

FIG. 1 is a schematic structural diagram of a vehicle control unit;

fig. 2 is a schematic flow chart of monitoring the torque direction of the vehicle control unit.

Detailed Description

The following describes embodiments of the present invention in detail. It should be understood that the examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Referring to fig. 2, an embodiment of the present invention provides a method for monitoring a torque direction of an electric vehicle, where the method includes:

in a first step S1, the vehicle controller receives the related CAN signal and collects the related hard-wire signal. In the system, signals received by the vehicle control unit are respectively gear signals sent by the gear controller through a CAN (controller area network) line, a vehicle speed signal, a brake pedal signal and a torque increasing and decreasing request signal sent by the chassis controller through the CAN line, an accelerator pedal signal acquired by the vehicle control unit, a battery long-time discharging power signal sent by a battery through the CAN line, a motor long-time executable maximum torque signal and a motor rotating speed signal sent by the motor through the CAN line, and a high-voltage accessory power consumption signal sent by the heat management control organization through the CAN line. In the step, the vehicle control unit CAN carry out communication verification before the received CAN signal and the hard wire signal, so that the calculation error caused by the calculation of the signal with the error reception is avoided. The communication diagnosis and the diagnosis of the accelerator pedal voltage are as follows.

For CAN line signals received by the whole vehicle controller, the following verification is carried out: firstly, CAN frame loss verification is carried out, after initialization of each controller is completed, when the state of the whole vehicle controller when the whole vehicle controller does not receive other control sent messages is larger than a certain multiple of a message period, a CAN frame loss fault is considered; secondly, Cyclic Redundancy Check (CRC), wherein a CRC parameter calculated by the vehicle controller according to corresponding source data is inconsistent with a CRC code transmitted along a source data frame, and a time period is greater than a message period of a certain multiple, and the vehicle controller determines that the CRC code fails; thirdly, counting and checking, wherein when the difference between the continuous and adjacent counting values of the frames where the controller receives the CAN signals is not equal to a certain value and the duration is greater than a certain multiple of the message period or the count value is unchanged and the duration is greater than a certain multiple of the message period, the counting and checking fault is considered. The fault processing comprises the steps of replacing the effective value at the last moment in the fault confirmation period, calculating the vehicle speed by using the motor rotating speed after the vehicle speed signal is lost after the fault confirmation period, continuously using the effective value at the last moment for the gear signal, enabling the brake pedal to be default and not to be stepped on, replacing the battery capacity signal by using half of the effective value at the last moment, replacing the motor capacity by using 0, and replacing the energy consumption power of the accessory by using a certain fixed value.

And acquiring accelerator pedal hard line signals acquired by the whole vehicle controller by adopting two independent acquisition circuits and diagnosing as follows. Firstly, two paths of pedal power supply voltages are diagnosed to exceed an upper limit or a lower limit, one path has problems, the other path is adopted to acquire the voltage of the accelerator pedal for calculation, the two paths have problems, and the opening degree of the accelerator pedal is calculated according to 0. And secondly, diagnosing that the two paths of accelerator pedal voltages exceed the upper limit or the lower limit, wherein one path has problems, calculating the other path of acquired accelerator pedal voltage, calculating the two paths of accelerator pedal voltages, calculating the opening degree of the accelerator pedal according to 0, checking the rationality of the third path of accelerator pedal voltage, and calculating the opening degree of the accelerator pedal by using the smaller path of voltage when the difference value of the two paths of accelerator pedal voltages exceeds a certain value.

And step S2, the vehicle controller simultaneously calculates the vehicle demand torque and determines the vehicle demand torque limit threshold value of the vehicle under the current working condition, and arbitrates the output. As shown in fig. 1, in the calculation process of the vehicle control unit, the demand request calculation unit 12 and the demand torque direction calculation unit 13 calculate at the same time, and output the result to the demand request direction arbitration unit 14. In the process of calculating the main controller module 1 of the vehicle control unit, the monitoring controller module 2 performs algorithm calculation check and program flow monitoring on part of the storage area (specifically, a storage area where the required torque direction calculating unit 13 and the required request direction arbitrating unit 14 are located) of the main controller module 1.

The demand request calculation unit 12 calculates a demand torque of the entire vehicle according to the signal received by the entire vehicle controller and the accelerator pedal signal acquired by the vehicle controller. The module firstly obtains the initial driver required torque by looking up different tables according to a vehicle speed signal and an accelerator pedal signal under different gears, then subtracts the consumed power of a high-voltage accessory according to the long-term generated power of a battery, then divides the power by the rotating speed of a motor, and finally multiplies a coefficient to obtain the driver maximum torque which can be supported by an energy source, wherein the driver maximum torque which can be supported by the energy source, the executable maximum torque of the motor and the driver required torque are reduced to be used as the driver required torque. When the increasing and decreasing torsion trunk of the chassis is activated in advance, the increasing and decreasing torsion trunk torque of the chassis is used as the required torque of the whole vehicle, and when the increasing and decreasing torsion trunk pre-activating function of the chassis is not activated, the required torque of a driver is used as the required torque of the whole vehicle. In order to ensure driving comfort, when the chassis torque increasing and decreasing function is not activated, certain gradient limitation should be performed on the torque required by a driver, particularly when the torque is changed from a positive value to a negative value or from a negative value to a positive value, when the chassis torque increasing and decreasing function is activated, in order to ensure safety, the gradient limitation should not be performed, and the chassis request torque should be directly output after considering capacity limitation.

The required torque direction calculating unit 13 is used for obtaining four working conditions according to the combination of the brake pedal signal, the vehicle speed signal, the gear signal and the acquired accelerator pedal signal received by the vehicle controller, and outputting an activation flag bit of each working condition and a threshold value of the required torque of the vehicle under each working condition through logic judgment. Four operating conditions are calculated as follows: in a first working condition (slow-forward working condition), when the gear is a forward gear, the vehicle speed is lower than a first preset value, and the brake is not stepped on, the activation flag bit of the first working condition is activated, and the torque threshold value is a value A (the value A is generally a small negative value) which is larger than a preset negative value; a second working condition, when the gear is a reverse gear, the vehicle speed is lower than a second preset value, and the brake is not stepped on, the activation zone bit of the second working condition is activated, and the torque threshold value is a value B (the value is generally a smaller positive value) which is larger than a preset positive value; in the third working condition, when the gear is a forward gear, the vehicle speed is higher than a third preset value, the opening degree of an accelerator pedal is larger than the first preset opening degree, and when the brake is not stepped on, the activation flag bit of the third working condition is activated, and the torque threshold value is zero; and under a fourth working condition, when the gear is a reverse gear, the vehicle speed is higher than a fourth preset value, the opening degree of an accelerator pedal is larger than a second preset opening degree, and when the brake is not stepped on, the activation flag bit of the fourth working condition is activated, and the torque threshold value is zero. The module outputs the activation flag bits and corresponding thresholds for four operating conditions. Even when the functions of energy recovery, single pedal and the like are considered, the torque required by the driver should meet the working condition when the vehicle runs normally.

The demand direction arbitration unit 14 arbitrates the vehicle demand torque output by the demand request calculation unit 12 and the four operating condition activation flag bits and corresponding threshold signals output by the demand torque direction calculation unit 13. When the first working condition is activated, the whole vehicle required torque output by the module 12 is compared with the value A, when the value of the whole vehicle required torque is smaller than or equal to the value A, the driver required torque is arbitrated to be output to be 0, when the second working condition is activated, the whole vehicle required torque output by the module 12 is compared with the value B, when the value of the whole vehicle required torque is larger than or equal to the value B, the driver required torque is arbitrated to be output to be 0, when the third working condition is activated, the driver required torque output by the module 12 is compared with 0, when the value of the whole vehicle required torque is smaller than 0, the driver required torque output by the module 12 is arbitrated to be output to be 0, when the four working conditions are activated, the driver required torque output by the module 12 is compared with 0, and when the value of the whole vehicle required torque is larger than 0, the driver required torque is arbitrated to be output to be 0.

The two modules of the demand torque direction calculating unit 13 and the demand request direction arbitrating unit 14 are completely independent from the code storage and running space of the demand request calculating unit 12, and the calculation is not influenced mutually, so as to ensure that the mutual influence is not influenced. The storage areas and the operation space sections where the two module codes of the torque calculation module and the demand request direction arbitration unit are located need to be subjected to bit reversal verification, and when the times of occurrence in a period of time reach a certain value, the controller is restarted, so that data are prevented from being modified unexpectedly. The codes of the two modules can be mirrored, input and output are preset, the codes are executed at intervals in the running process of the controller, and when the output result is different from the preset result, the controller is restarted, so that the code operation execution error of the controller is avoided.

The main controller monitoring unit 16 is implemented by a monitoring chip independent of the main chip, and monitors the program flow of the main controller chip through a question-answer checking mechanism. The specific implementation method is that a communication mechanism is established between a main controller module chip and a monitoring unit chip, the monitoring unit chip sends a problem to the main controller module chip at regular time in each driving cycle process, the main controller module chip selects a determined answer according to the problem and sends the determined answer to the monitoring unit chip, the monitoring unit chip compares the answer sent by the main controller module chip with a correct answer, when the answer is found to be inconsistent, the main controller module 1 is considered to have the problem and controls the main controller module to reinitialize and start, and meanwhile, a closing request of CAN communication is sent to an output module 15.

In a third step S3, the vehicle controller controls to output the driver-requested torque request according to the driver-requested torque request output from the request direction arbitration unit 14 and the CAN communication shutdown enable output from the main controller monitoring unit 16. Specifically, the output module 15 receives the driver demand torque request output by the demand request direction arbitration unit 14 and the CAN communication off enable of the main controller monitoring unit 16, when the CAN communication off enable signal is disabled, the output module 15 outputs the driver demand torque request output by the demand request direction arbitration unit 14, and when the CAN communication off enable signal is enabled, the output module 15 turns off the CAN communication, and the CAN communication is not transmitted or received.

The invention also provides an automobile comprising the vehicle control unit.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A monitoring method of an electric vehicle torque direction is applied to a vehicle control unit, and is characterized by comprising the following steps:

acquiring an accelerator pedal signal, and receiving a gear signal sent by a gear controller, a vehicle speed signal sent by a chassis controller, a brake pedal signal, a torque increasing and decreasing request signal, a battery long-time discharge power signal sent by a battery, a motor long-time executable maximum torque signal and a motor rotating speed signal sent by a motor, and a high-voltage accessory consumed power signal sent by a thermal management control device;

arbitrating whether the torque direction of the required torque of the whole vehicle is correct or not according to the determined required torque of the whole vehicle and a required torque limit threshold value of the whole vehicle under the current operating condition, and outputting the target required torque of the whole vehicle to a motor based on an arbitration result;

the steps of determining the required torque of the whole vehicle according to the vehicle speed signal, the accelerator pedal signal, the battery long-time discharge power signal, the motor long-time executable maximum torque signal, the high-voltage accessory consumed power signal, the motor rotating speed signal and the torque increasing and decreasing request signal comprise:

2. The method of claim 1, further comprising:

3. The method according to claim 1, wherein the step of determining the current operating condition of the whole vehicle according to the vehicle speed signal, the gear signal, the brake pedal signal and the accelerator pedal signal, and the required torque limit threshold value of the whole vehicle under the current operating condition comprises the following steps:

4. The method according to claim 3, wherein the step of arbitrating whether the torque direction of the vehicle required torque is correct or not according to the determined vehicle required torque and the required torque limit threshold of the vehicle under the current operating condition, and outputting the target vehicle required torque to the motor based on the arbitration result comprises:

if the torque direction of the finished automobile required torque is smaller than or equal to the target finished automobile required torque, arbitrating that the torque direction of the finished automobile required torque is correct, and determining the finished automobile required torque as the target finished automobile required torque to be output to a motor; if so, arbitrating the torque direction error of the finished automobile required torque, and outputting the target finished automobile required torque with the value of zero to the motor;

if the whole vehicle is currently in a third working condition, judging whether the required torque of the whole vehicle is larger than zero;

5. The method of claim 1, wherein a vehicle control unit receives signals through a CAN bus from the gear controller, the chassis controller, the battery, the motor and the thermal management control device, and performs CAN frame loss check, cyclic redundancy check and counting check on the signals received from the CAN bus;

6. A vehicle control unit, comprising:

the demand request direction arbitration unit arbitrates whether the torque direction of the whole vehicle demand torque is correct or not according to the determined whole vehicle demand torque and a demand torque limit threshold value of the whole vehicle under the current operation working condition, and outputs the target whole vehicle demand torque to the motor through the output module based on the arbitration result;

the demand request calculation unit is specifically configured to:

performing table look-up on the vehicle speed signal and the accelerator pedal signal according to a preset relationship to obtain an initial driver required torque;

7. The vehicle control unit according to claim 6, further comprising:

the monitoring controller module is connected with the output module;

8. The vehicle control unit according to claim 7, wherein the monitoring controller module sends a question to the main controller module at regular time during each driving cycle, the main controller module feeds back an answer based on the question output, the monitoring controller module compares the answer output by the main controller module with a preset answer stored in advance and corresponding to the question, and if the comparison is not consistent, a main controller module fault is determined; otherwise, determining that the main controller module has no fault.

9. An automobile, characterized by comprising the vehicle control unit of claims 6 to 8.