CN113335284B

CN113335284B - Control method and control system for automobile hill start

Info

Publication number: CN113335284B
Application number: CN202110726502.2A
Authority: CN
Inventors: 吴兴强; 王亚楠; 唐梨; 任俊锋; 朱小葵
Original assignee: Dongfeng Huashen Motor Co Ltd
Current assignee: Dongfeng Huashen Motor Co Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2022-11-18
Anticipated expiration: 2041-06-29
Also published as: CN113335284A

Abstract

The application relates to a control method and a control system for automobile hill starting, wherein the control method comprises the following steps: when a starting intention exists, acquiring a current load demand torque value C; calculating a power torque value E of the engine when the load torque percentage of the engine is at a first set value D according to the current load demand torque value C; and controlling the engine to output the power torque value E to assist the starting. According to the embodiment of the application, the operation of releasing the hand brake is changed into releasing the brake pedal, and the operation of the accelerator is directly requested to be completed after the power torque value E of the engine is calculated through a relevant controller such as a vehicle controller or a vehicle body controller, and the auxiliary starting can be completed. The controller controls the vehicle to start according to the operation of a driver, the vehicle can start more stably, the situations of flameout, vehicle slipping and jerky starting cannot occur, and the operations of starting interruption, restarting and the like are easier and quicker in the starting process.

Description

Control method and control system for automobile hill start

Technical Field

The application relates to the technical field of automobile control, in particular to a control method and a control system for automobile hill starting.

Background

A vehicle provided with an automatic transmission (AMT/AT/DCT) can utilize the transmission to control the torque of an engine and the linkage state of a clutch, and the engine is ensured to increase the output torque when the vehicle starts so as to transmit reasonable power to wheels, so that the wheels can keep still or roll forwards.

Vehicles equipped with body stability systems (ESP/ESC) or electronic brake control systems (EBS) may utilize brake controllers to control brake pad clamping force, increase braking force as the wheels turn backward, and stabilize for a period of time during which the driver may take a refueling door or other action to hold the vehicle stationary or moving forward to avoid rolling.

Commercial vehicles are guided by practicality and economy, a large number of vehicles on the market are only provided with a traditional Manual Transmission (MT) and a basic anti-lock braking system (ABS), no hill starting auxiliary function is provided, and a driver usually realizes starting by loosening the clutch, the oil filling door and the hand brake after engaging gears. The mode needs to be operated by the left foot, the right foot and the right hand simultaneously, and can be successfully completed only with certain familiarity to vehicles and roads, otherwise, the mode can cause flameout, vehicle sliding and violent starting due to unreasonable operation, and traffic accidents are easily caused.

Disclosure of Invention

The embodiment of the application provides a control method and a control system for automobile hill starting, and aims to solve the problems that when the hill starting is carried out in the related art, the operations of releasing a clutch, an oil filling door and a hand brake after engaging a gear are adopted, a left foot, a right foot and a right hand are required to be operated simultaneously, and flameout, vehicle sliding and violent starting are easily caused due to unreasonable operation, so that traffic accidents are further caused.

In a first aspect, a method for controlling hill start of an automobile is provided, which includes the following steps:

when a starting intention exists, acquiring a current load demand torque value C;

calculating a power torque value E of the engine when the load torque percentage of the engine is at a first set value D according to the current load demand torque value C;

and controlling the engine to output the power torque value E to assist the starting.

In some embodiments, the control method further comprises:

judging whether the current load torque percentage A is less than or equal to a second set value or not;

if yes, the auxiliary starting is not carried out;

otherwise, the step of obtaining the current load demand torque value C is entered.

In some embodiments, the value range of the first setting value D is: d is more than or equal to 80 percent and less than or equal to 90 percent; and/or the presence of a gas in the gas,

obtaining a current load demand torque value C, comprising the steps of:

calculating a current load demand torque value C according to the current load torque percentage A and the engine reference torque value B; or, acquiring the current output torque value of the engine, and taking the current output torque value as the current load demand torque value C.

In some embodiments, after calculating the power torque value E of the engine, the control method further comprises the steps of, before controlling the engine to output the power torque value E to assist the vehicle start:

and if the calculated power torque value E of the engine is larger than the maximum output torque value of the engine, taking the maximum output torque value of the engine as the power torque value E of the engine.

In some embodiments, after controlling the engine to output the motive torque value E to assist the launch, the control method further comprises exiting the assist launch.

In some embodiments, the exit-assisted launch comprises:

judging whether a trigger condition exists, wherein the trigger condition comprises any one of the conditions that an accelerator pedal is stepped on, a clutch pedal is stepped on the lowest point, a brake pedal is stepped on the lowest point, the vehicle speed is greater than a set vehicle speed, a hand brake is in a parking state, a gear of a gearbox is in a neutral gear state, the load torque percentage of an engine is less than or equal to a second set value, and the time for the engine to continuously output a power torque value E is greater than set time;

if yes, quitting the auxiliary starting;

otherwise, the auxiliary starting is continuously executed.

In some embodiments, the set vehicle speed is 5km/h; and/or, the second set value is 15%; and/or the set time is 3s.

In some embodiments, the control method further comprises a starting intention judging step.

In some embodiments, the determining the initiative intention step includes:

judging whether the vehicle speed is 0, the hand brake is in a release state, the gear of the gearbox is in a non-neutral state, the clutch pedal leaves the lowest point and does not reach the highest point and the brake pedal leaves the lowest point at the same time;

if the two conditions are met simultaneously, a starting intention exists;

otherwise, there is no breakaway intent.

In a second aspect, a control system for hill start of a vehicle is provided, which comprises a controller, a controller and a controller, wherein the controller is used for acquiring a current load demand torque value C when a starting intention exists;

the controller is also used for calculating a power torque value E of the engine when the load torque percentage of the engine is at a first set value D according to the current load demand torque value C; and (c) a second step of,

The beneficial effect that technical scheme that this application provided brought includes:

compared with a starting mode realized by adopting the operations of releasing the clutch, the accelerator and the hand brake after engaging a gear, the embodiment of the invention changes the operation of releasing the hand brake into releasing the brake pedal, and the operation of the accelerator is directly finished by requesting the engine to finish after calculating the power torque value of the engine through a relevant controller such as a whole vehicle controller or a vehicle body controller, and the like, thereby completing the auxiliary starting. The controller controls the vehicle to start according to the operation of a driver, so that the vehicle can start more stably without flameout, sliding and jerky starting, and the operations of stopping starting, restarting and the like in the starting process are easier and quicker.

The brake pedal is controlled to control the brake force to be sensitive and easy to operate compared with a hand brake, the right hand is liberated, the steering wheel is mastered by both hands, and the emergency response is more effective. When starting, the left foot slowly releases the clutch pedal, the right foot slowly releases the brake pedal, so that the starting is interrupted or the restarting is more convenient, meanwhile, the brake pedal and the clutch pedal can only be trampled in an emergency reaction, the power output and the brake are directly interrupted, the risk of stepping on the accelerator by mistake is avoided, and traffic accidents are reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flowchart of a method for controlling hill start of an automobile according to an embodiment of the present disclosure;

fig. 2 is a flow chart of determining starting assistance provided in the embodiment of the present application;

FIG. 3 is a flowchart of exit assist launch provided by an embodiment of the present application;

fig. 4 is a flowchart of the judgment of the starting intention according to the embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

Referring to fig. 1, the method for controlling hill start of an automobile provided in the embodiment of the present application includes the following steps:

and controlling the engine to output a power torque value E to assist the starting.

The principles of the present application are illustrated below by way of an example:

if the present load torque percentage of the engine a =95% and the reference engine torque value B =2000N in the present engine speed and throttle state, the present load demand torque value C =2000N × 95% =1900N can be calculated, and the present output torque value of the engine is also 1900N.

This current load demand torque value C is the sum of the current gravitational component, frictional force, braking force, other resistance, and the like, all of which oppose the forward movement of the vehicle, and is collectively referred to as the current load demand torque value. The vehicle can proceed forward only by overcoming this resistance.

Meanwhile, the resistance is changed in real time, the largest influence factor is the opening degree of a brake pedal and a clutch pedal, the larger the opening degree of the brake pedal is, the larger the braking force is, the larger the resistance is, the smaller the opening degree of the clutch pedal is, and the larger the resistance transmission value is.

Normally, the brake pedal and the clutch pedal are slowly released to reduce the resistance when starting, when the brake pedal is completely released, C is minimized, the minimum value is the lowest starting force, and if the engine cannot provide driving force larger than the minimum value, the vehicle cannot be started.

In order to overcome the 1900N force, the engine is required to output a power torque value E, and when the hill start condition of the engine is calibrated, the load torque percentage of the engine is expected to be at the first set value D, and if D is 80%, the engine is required to output the power torque value E =1900N/80% =2375N at this time, so that the engine is required to output the output torque of 2375N instead of the current 1900N.

Therefore, compared with a starting mode realized by releasing the clutch, the accelerator and the hand brake after the gear is engaged, the embodiment of the application changes the operation of releasing the hand brake into releasing the brake pedal, and the operation of the accelerator is directly finished by requesting the engine to finish after a power torque value E of the engine is calculated by a relevant controller such as a whole vehicle controller or a vehicle body controller, and the like, so that the auxiliary starting can be finished. The controller controls the vehicle to start according to the operation of a driver, so that the vehicle can start more stably without flameout, sliding and jerky starting, and the operations of stopping starting, restarting and the like in the starting process are easier and quicker.

The brake pedal is controlled to control the brake force to be more sensitive than a hand brake and easy to operate, the right hand is liberated, the steering wheel is mastered by two hands, and emergency response is more effective. When starting, the left foot slowly releases the clutch pedal, the right foot slowly releases the brake pedal, so that the starting is interrupted or the restarting is more convenient, meanwhile, the brake pedal and the clutch pedal can only be trampled in an emergency reaction, the power output and the brake are directly interrupted, the risk of stepping on the accelerator by mistake is avoided, and traffic accidents are reduced.

It should be noted that the first setting value D is not changed after being set, that is, the first setting value D is usually not changed after the vehicle is off-line and the first setting value D is set, and the first setting value D can be reset according to the vehicle condition during the calibration process.

Referring to fig. 2, in a preferred embodiment, the control method further includes the following step of determining to assist the start:

if yes, the auxiliary starting is not carried out;

In this embodiment, the second setting value is set according to an actual requirement, for example, may be set to 14%, 15%, or 16%, and the current load torque percentage a and the second setting value are subjected to a size determination, so that if the current load torque percentage a is smaller, for example, the current load torque percentage a of the engine is smaller than 15%, it is considered that the vehicle is unloaded or loaded very little, and the idle output power of the engine is sufficient for the vehicle to start normally, and at this time, no start assist is required. And if the current load torque percentage A is larger, for example, the current load torque percentage A of the engine is larger than 15%, the vehicle load is considered to be larger, the idle speed output power of the engine is not enough to enable the vehicle to start normally, and auxiliary starting is needed at the moment.

In a preferred embodiment, during setting, the first setting value D cannot be too large or too small, and if D is too small, it means that the requested engine output torque is much larger than the torque required by the current load, i.e. the engine overspray, the rotation speed suddenly rises, the noise and the vibration are large, and if D is too large, the output power is made to be even with the load power, the rotation speed will drop, and finally the flameout will be caused to be suppressed, so the value range of the first setting value D is usually: d is between 80 and 90 percent.

In a preferred embodiment, there are two methods for obtaining the current load demand torque value C, one of which is to calculate the current load demand torque value C based on the current load torque percentage a and the engine reference torque value B; and secondly, acquiring a current output torque value of the engine, and taking the current output torque value as a current load demand torque value C.

The current load torque percentage A of the engine is obtained by calculation of an engine integrated sensor; the engine reference torque value B is an engine test calibration value, has a linear relation with the engine speed, and is generally preset in a memory of an engine controller, and different rotating speeds correspond to different reference torques; the current output torque value of the engine is obtained by multiplying the reference torque by the torque percentage, or is directly calculated by part of factory engines and then broadcasted to the CAN bus. Therefore, the current load torque percentage, the reference torque and the current output torque of the engine CAN be obtained on the CAN bus.

In a preferred embodiment, after calculating the motive power torque value E of the engine, and before controlling the engine to output the motive power torque value E to assist the start of the vehicle, the control method further includes the steps of:

if the calculated power torque value E of the engine is larger than the maximum output torque value of the engine, the maximum output torque value of the engine is taken as the power torque value E of the engine.

In a preferred embodiment, after controlling the engine to output the power torque value E to assist the take off, the control method further comprises exiting the assist take off.

Specifically, referring to fig. 3, exiting the assisted launch includes the steps of:

judging whether a trigger condition exists or not, wherein the trigger condition comprises any one of the conditions that an accelerator pedal is stepped on, a clutch pedal is stepped on the lowest point, a brake pedal is stepped on the lowest point, the vehicle speed is greater than a set vehicle speed, a hand brake is in a parking state, a gear of a gearbox is in a neutral gear state, the load torque percentage of an engine is less than or equal to a second set value and the time for continuously outputting a power torque value E of the engine is greater than set time;

if yes, quitting the auxiliary starting; that is, when any condition occurs in the process of stepping on an accelerator pedal, stepping on a clutch pedal to the lowest point, stepping on a brake pedal to the lowest point, stepping on the vehicle speed more than a set vehicle speed, parking a hand brake, neutral gear of a gearbox, the load torque percentage of an engine less than or equal to a second set value and the time of the continuous output power torque value E of the engine more than a set time, the auxiliary starting is exited.

Otherwise, the auxiliary starting is continuously executed.

In a preferred embodiment, the vehicle speed is set to 5km/h, the second set value is 15% and the set time is 3s.

In a preferred embodiment, the control method further includes a start intention judgment step.

Specifically, referring to fig. 4, the starting intention determining step includes:

if the two conditions are met simultaneously, a starting intention exists;

otherwise, there is no breakaway intent.

The embodiment of the application also provides a control system for automobile hill starting, which comprises a controller, wherein the controller is used for acquiring the current load demand torque value C when a starting intention exists;

the controller is also used for calculating a power torque value E of the engine when the load torque percentage of the engine is at a first set value D according to the current load demand torque value C; and the number of the first and second groups,

In a preferred embodiment, the controller is further configured to determine whether the current load torque percentage a is less than or equal to a second set value; if yes, the auxiliary starting is not carried out; otherwise, the step of obtaining the current load demand torque value C is entered.

In a preferred embodiment, the controller is further configured to use the maximum output torque value of the engine as the motive torque value E of the engine if the calculated motive torque value E of the engine is greater than the maximum output torque value of the engine.

In a preferred embodiment, the controller is further configured to determine whether a trigger condition exists, where the trigger condition includes any one of an accelerator pedal being pressed, a clutch pedal being pressed to the lowest point, a brake pedal being pressed to the lowest point, a vehicle speed being greater than a set vehicle speed, a hand brake being in a parking state, a transmission gear being in a neutral state, a load torque percentage of the engine being less than or equal to a second set value, and a time for which the engine continues to output a power torque value E being greater than a set time; if the auxiliary starting exists, the auxiliary starting is quitted; otherwise, the auxiliary starting is continuously executed.

In a preferred embodiment, the controller is further configured to determine whether the vehicle speed is 0, the hand brake is in a release state, the gearbox gear is in a non-neutral state, the clutch pedal leaves the lowest point and does not reach the highest point, and the brake pedal leaves the lowest point at the same time; if the two conditions are met simultaneously, a starting intention exists; otherwise, there is no breakaway intent.

The controller can adopt a whole vehicle controller or a vehicle body controller.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly and encompass, for example, both fixed and removable coupling as well as integral coupling; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for automobile hill start is characterized by comprising the following steps:

when a starting intention exists, calculating a current load demand torque value C according to the current load torque percentage A and the engine reference torque value B;

2. A method for controlling hill start of a vehicle according to claim 1, wherein: the control method further comprises the following steps:

if yes, not performing auxiliary starting;

3. The method for controlling hill start of a vehicle according to claim 1, wherein:

the value range of the first set value D is as follows: d is between 80 and 90 percent.

4. A method for controlling hill start of a vehicle according to claim 1, wherein:

after calculating the power torque value E of the engine and before controlling the engine to output the power torque value E to assist the start, the control method further comprises the following steps:

5. A method for controlling hill start of a vehicle according to claim 1, wherein:

after controlling the engine to output the motive torque value E to assist the take-off, the control method further includes exiting the assist take-off.

6. A method for controlling hill starts for a vehicle according to claim 5 wherein said exit-assisted start comprises:

if yes, quitting the auxiliary starting;

otherwise, the auxiliary starting is continuously executed.

7. A method for controlling hill start of a vehicle according to claim 6, wherein:

the set speed is 5km/h; and/or, the second set value is 15%; and/or the set time is 3s.

8. A method for controlling hill start of a vehicle according to claim 1, wherein:

the control method further comprises a starting intention judging step.

9. The method for controlling hill start of a vehicle according to claim 8, wherein the step of determining the intention of start includes:

if the two conditions are met, a starting intention exists;

otherwise, there is no breakaway intent.

10. A control system for automobile hill start is characterized by comprising a controller, a controller and a controller, wherein the controller is used for calculating a current load demand torque value C according to a current load torque percentage A and an engine reference torque value B when a start intention exists;